ORGANIC COMPOUNDS

Abstract: The invention relates to novel crosslinkable copolymers of formula (1) wherein the variables are as defined in the claims. The copolymers of the invention are especially useful for the manufacture of biomedical moldings, for example ophthalmic moldings such as in particular contact lenses.

Description: Organic Compounds The present invention relates to novel crosslinkable copolymers, to a process for the preparation thereof and to the use thereof for the manufacture of moldings, especially ophthalmic moldings. U.S patents Nrs. 5,760,100 or 5,807,944 disclose crosslinkable amphiphilic block copolymers comprising a hydrophobic middle block to which are linked two or more hydrophilic blocks. While the materials disclosed therein have proven to be very effective as bulk material for the manufacture of biomedical articles, in particular ophthalmic moldings, their surface properties, in particular the wettability characteristics, are in general not sufficient to use them as a biomedical device without previously applying a suitable coating on their surface. Therefore, there is a need to provide polymeric materials which may be used for the manufacture of biomedical articles such as ophthalmic moldings per se without a subsequent surface modication. Surprisingly, it now has been found that articles, particularly biomedical devices such as contact lenses, with an improved wettability may be obtained from novel amphiphilic block copolymers comprising a hydrophobic segment to which are covalently attached moieties comprising a crosslinkable ethylenically unsaturated group as well as surface-modifying hydrophilic segments. The present invention therefore relates to an amphiphilic block copolymer of formula wherein A is a hydrophobic polysiloxane or perfluoroalkyl polyether segment; B is a surface-modifying hydrophilic segment having a weight average molecular weight of >100 that is devoid of a crosslinkable group; Q is a moiety comprising at least one crosslinkable ethylenically unsaturated group; (alk) is C 2 -C 2 o-alkylene which is unsubstituted or substituted by hydroxy; LL l_2 and L 3 are each independently of the other a linking group; p1 and q1 are each independently of the other an integer from 1 to 12; and either t is 0 and p and q are each independently of the other an integer from 1 to 25; or t is an integer from 1 to 8 and p and q are each 0. In case that t is 0, p and q are each independently of the other preferably an integer from 2 to 20, more preferably 2 to 15 and in particular 2 to 10. In case that p and q are each 0, t is preferably an integer from 1 to 6, more preferably 1 to 4 and in particular 2. p1 is preferably an integer from 1 to 6, more preferably 1 to 4 and in particular 1 or 2. q1 is preferably an integer from 1 to 10, more preferably 1 to 8, and in particular 1 to 4. One group of suitable block copolymers of the invention conforms to the formula wherein A, B, Li, L 2 , L 3 , Q, (alk), p1 and q1 are each as defined above. Another group of suitable block copolymers of the invention conforms to formula (B - L • 2 2)'q ■ 0-1 - Q)p (1b), wherein A, B, L 1f L 2 and Q are each as defined above, and p and q are each independently of the other an integer from 1 to 25, preferably 2 to 20, more preferably 2 to 15 and in particular 2 to 10. In one embodiment of the invention A is a polysiloxane segment of formula wherein (alk') is alkylene having 1 to 20 carbon atoms which may be interrupted by -O-; x is 0 or 1 ; 80 to 100 % of the radicals R 1t FV, Ri", R 2 , R 2 ', R 2 ", R 3 and R 4 , independently of one another, are Cι-C 8 -alkyl, and 0-20% of the radicals R 1f Ri', Ri", R 2 , R 2 ', R 2 ", R 3 and R 4 , independently of one another, are unsubstituted or CrC 4 alky!- or d-C - alkoxy-substituted phenyl, fluoro(Cι-Cι 8 -alkyl) or cyano(Cι-Cι 2 -alkyl), Si is an integer from 5 to 700; s 2 is the sum of (p+q+t-2) if x is 0, and is the sum of (p+q+t) if x is 1 ; wherein p, q and t are as defined above, and the sum (Si+5 2 ) is from 5 to 700. In a preferred meaning of the polysiloxanes of formula (2), the sum (Sι+s 2 ) is an integer from 10 to 500, more preferably 10 to 300, even more preferably 20 to 150 and in particular preferably 50 to 140. (alk') is preferably C 2 -C 8 -alkylene, which may be interrupted by -O- and more preferably C 2 -C 6 -alkylene which may be interrupted by -O-. Examples of particular preferred radicals (alk') are linear or branched C 2 -C 6 alkylene or a radical -(CH2) 1 .3-O-(CH 2 )ι-3-, especially C 2 -C 4 -alkylene or a radical -(CH 2 )2-3-O-(CI--2)2-3-. Preferably the radicals R 1f R R R 2 , R 2 \ R 2 ", R 3 and R 4 are each independently of one another Cι-C β -alkyl, more preferably each CrC 4 -alkyl, more preferably each Cι-C 2 -alkyl and in particular each methyl. One embodiment of suitable polysiloxane hydrophobic blocks (A) emcompasses a radical of the above formula (2), wherein x is 0, s2 is 0, s1 is an integer from 5 to 700, preferably 10 to 500, more preferably 10 to 300, even more preferably 20 to 150 and in particular preferably 50 to 140, R L R^, R R 2 , R 2 ', R 2 " and R 3 are each independently of one another d-C 6 - alkyl, and for (alk') the above given meanings and preferences apply. In this case, either t in formula (1 ) is 0 and p and q are each 1 , or, preferably, p and q are each 0 and t is 2. Another embodiment of suitable polysiloxane hydrophobic blocks (A) emcompasses a radical of the above formula (2), wherein x is 0, s 2 is the sum of (p+q+t-2), and for R ( R^, Ri", R 2 , R 2 ', R 2 ", R 3 ,(alk'), p, q and t the above-given meanings and preferences each apply. Still another embodiment of suitable polysiloxane hydrophobic blocks (A) emcompasses a radical of the above formula (2), wherein x is 1 , s 2 is the sum of (p+q+t), and for R 1 ( R R R2. R2'. R2", R3, R , p, q and t the above-given meanings and preferences each apply. ln another embodiment of the invention, A is a perfluoroalkyl polyether segment of formula -(E) k -Z-CF 2 -(OCF 2 ) y1 -(OCF 2 CF 2 ) y2 -OCF 2 -Z-(E) k - (3), in which y1 + y2 is a number in the range from 10 to 100; each Z, independently of the other, is a divalent radical having up to 12 carbon atoms or a bond; each E, independently of the others, is alkoxy, e.g. -(OCH 2 CH 2 ) r -. where r has a value of from 0 to 2 as a statistical average, and where the link -Z-E- represents the sequence -Z-(OCH 2 CH 2 ) r -; and k is 0 or 1 ; Z is preferably a bond, Cι-C 8 -alkylene or -CONH-phenylene, in which the -CO- moiety is linked to a CF 2 group. Z is particularly preferably Crd-alkylene, in particular methylene. The perfluoroalkoxy units OCF 2 and OCF 2 CF 2 having the indices y1 and y2 in Formula (3) can have a random distribution. The sum of the indices y1+v2 is preferably a number in the range from 10 to 50, particularly preferably from 10 to 30. The ratio y1 :y2 is preferably in the range from 0.5 to 1.5, in particular in the range from 0.8 to 1.2. In one embodiment of the invention, the segment A may comprise one of the polymers illustrated above. According to another embodiment, the polymer in segment A may comprise more than one kind of polymers as illustrated above, e.g., may comprise polysiloxane subsegments of formula (2) and perfluoroalkylene polyether units of formula (3). Preferably, segment A is a polysiloxane of formula (2). Segments A of the prepolymers of the invention have a mean molecular weight of for example in the range from about 1 ,000 to about 50,000, preferably in the range from about 1 ,500 to about 30000 and particularly preferably in the range from about 2,000 to about 20,000. Li, L 2 and L 3 are each independently of the other, for example, a bivalent linking group of formula - Xi - C(O) -NH - R 10 - NH - C(O) - X 2 - (4a), - X - C(O) - R 10 - C(O) - X 2 - (4b), - C(O) - X 2 - (4d), or wherein Xi and X 2 are each independently of the other a group -O-, -S- or -NR 0 -, Ro is hydrogen or C C -alkyl, and Rι 0 is linear or branched Cι-C 18 -alkylene or unsubstituted or C C 4 -alkyl- or C C 4 -alkoxy-substituted C 6 -C 10 -arylene, C 7 -C 18 -aralkylene, C 6 -Cι 0 -arylene- Cι-C 2 -alkylene-C 6 -Cιo-arylene, C 3 -C 8 -cycloalkylene, C 3 -C 8 -cycloalkylene-Cι-C 6 -all<ylene, Cs-Cβ-cycloalkylene-Ci^-alkylene-Cs-Cβ-cycloalkylene or CrCe-alkylene-Cs-Cs- cycloalkylene-Cι-C 6 -alkylene. The linking groups Li and L 2 of formulae (4a) - (4e) are to be understood that the left bond is in each case directed to A or (alk) and the right bond is directed to Q or B. The linking group l_3 of formulae (4a) - (4e) is to be understood that the left bond is directed to A and the right bond is directed to (alk). If Xi or X 2 is a group -NR 0 -, Ro is preferably methyl, ethyl or in particular hydrogen. In formulae (4a)-(4e) Xi and X 2 are each independently of the other preferably a group -O- or -NRo- and more preferably -O- or -NH-. In formula (4e) Xi is most preferably -O- or -NH- and X 2 is -NH-. Rio as alkylene in formulae (4b) is preferably linear or branched Cι-Ci 2 -alkylene, more preferably Cι-C 6 -alkylene and most preferably C C 4 -alkylene. Rio as alkylene in formula (4a) is preferably a linear or branched C 3 -Cι 4 alkylene radical, more preferably a linear or branched C -Cι alkylene radical and most preferably a linear or branched C 6 -Cιoalkylene radical. When Rio is arylene, it is, for example, naphthylene or especially phenylene, each of which may be substituted, for example, by Cι-C 4 -alkyl or by C C 4 -alkoxy. Preferably, Rι 0 as arylene is 1 ,3- or 1 ,4-phenylene that is unsubstituted or substituted by d-d-alkyl or by d- C 4 -alkoxy in the ortho-position to at least one linkage site. R 10 as aralkylene is preferably naphthylalkylene and most preferably phenylalkylene. The alkylene group in aralkylene contains preferably from 1 to 12, more preferably from 1 to 6 and most preferably from 1 to 4 carbon atoms. Most preferably, the alkylene group in aralkylene is methylene or ethylene. When R 10 is cycloalkylene, it is preferably C 5 -C 6 cycloalkyiene and most preferably cyclo- hexylene that is unsubstituted or substituted by methyl. When R 10 is cycloalkyiene-alkylene, it is preferably cyclopentylene-Cι-C -alkylene and especially cyclohexylene-d-C 4 -alkylene, each unsubstituted or mono- or poly-substituted by Cι-C -alkyl, especially methyl. More preferably, the group cycloalkyiene-alkylene is cyclo- hexylene-ethylene and, most preferably, cyclohexylene-methylene, each unsubstituted or substituted in the cyclohexylene radical by from 1 to 3 methyl groups. When Rio is alkylene-cycloalkylene-alkylene, it is preferably Cι-C 4 -alkylene-cyclopentylene- d-C 4 -alkylene and especially Cι-C -alkylene-cyclohexylene-C C 4 -alkylene, each unsubstituted or mono- or poly-substituted by d-C 4 -alkyl, especially methyl. More preferably, the group alkylene-cycloalkylene-alkylene is ethylene-cyclohexylene-ethylene and, most preferably, is methylene-cyclohexylene-methylene, each unsubstituted or substituted in the cyclohexylene radical by from 1 to 3 methyl groups. R 10 as C 3 -C 8 -cycloalkylene-CrC 2 -alkylene-C 3 -C 8 -cycloalkylene or Ce-do-arylene-d^- alkylene-C-e-do-arylene is preferably Cs-Cβ-cycloalkylene-methylene-Cs-Ce-cycloalkylene or phenylene-methylene-phenylene, each of which may be unsubstituted or substituted in the cycloalkyl or phenyl ring by one or more methyl groups. The radical R 10 in formula (4a) has a symmetrical or, preferably, an asymmetrical structure. A preferred group of linking groups U or L 2 comprises those of formula (4a), wherein R 10 is linear or branched C 6 -Cι 0 alkylene; cyclohexylene-methylene or cyclohexylene-methylene- cyclohexylene each unsubstituted or substituted in the cyclohexyl moiety by from 1 to 3 methyl groups; or phenylene or phenylene-methylene-phenylene each unsubstituted or substituted in the phenyl moiety by methyl. The bivalent radical Rio in formula (4a) is derived preferably from a diisocyanate and most preferably from a diisocyanate selected from the group isophorone diisocyanate (IPDI), toluylene-2,4-diisocyanate (TDI), 4,4'-methylenebis(cyclohexyl isocyanate), 1 ,6- diisocyanato-2,2,4-trimethyl-n-hexane (TMDI), methylenebis henyl isocyanate), methylenebis(cyclohexyl-4-isocyanate) and hexamethylene diisocyanate (HMDI). Another preferred group of linking groups Li or L 2 comprises those of formula (4b), wherein R 10 is d-Ce-alkylene or 1 ,3- or 1 ,4-phenylene. Further preferred linking groups Li or L 2 comprise -O(O)C-, -C(O)O-, -HNC(O)-, -C(O)NH-, -OC(O)NH-, -NHC(O)O- or -HNC(O)NH-. Li is most preferably a radical of formula (4a), (4c) or in particular (4e). L 2 is most preferably a radical of formula (4c), (4d) or in particular (4a). A preferred group of linking groups L 3 comprises those of formula (4a), (4c) or (4d), in particular (4c), wherein the above meanings and preferences apply. Suitable hydrophilic segments B are for example: (i) non-ionic segments, for example a polyoxyalkylene, polysaccharid, polypeptide, poly(vinylpyrrolidone), polyhydroxyalkylacrylate or -methacrylate, polyacyl alkylene imine, polyacryl amide, polyvinyl alcohol, polyvinyl ether or polyol; (ii) polyionic segments, for example a polycationic segment such as a polyallylammonium, polyethyleneimine, polyvinylbenzyltrimethylammonium, polyaniline, sulfonated polyaniline, polypyrrole or polypyridinium segment, or a polyanionic segment such as a poiyacrylic or polymethacrylic acid, a polythiophene-acetic acid, a polystyrenesulfonic acid, or a zwitterionic segment; or (iii) telomer segments which may be non-ionic, anionic, cationic or zwitterionic. Polyionic segments in each case encompass the free amine, imine or acid or a suitable salt thereof. Some examples of preferred hydrophilic segments B are a polyoxyalkylene, such as a polyethylene glycol or polypropylene glycol or a block copolymer thereof, a poly(vinylpyrroli- done), poly(hydroxyethylacrylate), poly(hydroxyethylmethacrylate), polyacrylamide, poly(N,N-dimethylacrylamide), poiyacrylic or polymethacrylic acid, a polyacyl alkylene imine or a copolymeric mixture of two or more of the above-mentioned polymers. B as a polyoxyalkylene radical may correspond, for example, to formula R 5 -[(O-CHR 7 -CHR 6 ) b -(O-CH 2 -CH 2 ) a ]-(O-(alk")) c - (5) wherein R 5 is hydrogen, d-C 2 -alkyl, Cι-C 24 -alkanoyl or a radical -(alk")-NH 2 , one of the radicals R 6 and R 7 is hydrogen and the other is methyl, (alk") is d-C 6 -alkylene, c is the number 0 or 1 , and each of a and b independently of the other is a number from 0 to 100, the sum of (a+b) being from 2 to 100. In formula (5), R 5 is preferably hydrogen, Cι-C 4 -alkyl or d-C -alkanoyl, more preferably hydrogen or CrC 2 -alkyl and in particular hydrogen, (alk") is preferably C 2 -C 4 -alkylene and in particular 1 ,2-ethylene or 1 ,2- or 1 ,3-propylene. The variable c preferably is an integer of 0. Each of a and b independently of the others is preferably a number from 0 to 80, the sum of (a+b) being from 3 to 80. Most preferably, each of a and b independently of the others is a number from 0 to 50, the sum of (a+b) being from 4 to 50 and especially from 8 to 50. A preferred embodiment relates to polyoxyalkylene segments of formula (5) wherein b and c are each 0, R 5 is hydrogen, C C -alkyl or Cι-C -alkanoyl, and for the variable a the above- mentioned meanings and preferences apply. B as a polyacyl alkylene imine may correspond, for example, to a segment of formula wherein R 8 is hydrogen; C r Cι 2 -alkyl unsubstituted or substituted by hydroxy or fluoro and/or uninterrupted or interrupted by oxygen; C 5 -C 8 -cycloalkyl; phenyl; or benzyl, R 9 is, for example, d-Cι 2 -alkyl, benzyl, C 2 -C 4 -alkanoyl, benzoyl or phenyl, preferably Cι-C 6 -alkyl, acetyl or benzyl and in particular Cι-C 4 -alkyl, and z is an integer from 2 to 150. R 8 is preferably Cι-C 8 -alkyl which is unsubstituted or substituted by hydroxy or fluorine and/or is uninterrupted or interrupted by -O-; or is C 3 -C 8 -alkenyl. R 8 is more preferably d- C -alkyl, hydroxy-Cι-C 4 -alkyl or trifluoromethyl and most preferably methyl, z is preferably an integer from 4 to 100, more preferably 4 to 50 and especially 5 to 20. B as a telomer may correspond, for example, to a segment of formula wherein (Alk") is C 2 -Cι 2 -alkylene, T is a monovalent group that is suitable to act as a polymerization chain-reaction terminator, m and n are each independently of another an integer from 0 to 250, wherein the total of (m+n) is an integer from 2 to 250, R 20 and R 20 ' are each independently of the other hydrogen or Cι-C 4 -alkyl, preferably hydrogen or methyl, R 21 is a hydrophilic non-ionic, anionic, cationic or zwitterionic substituent; and R 21 ' independently has the meaning of R 21 or, in case of m>n, may also be a hydrophobic substituent. Accordingly, the telomer chain of formula (19) may be a charged chain containing anionic, cationic and/or zwitterionic groups or may be an uncharged chain. In addition, the telomer chain may comprise a copolymeric mixture of uncharged and charged units. The distribution of the charges within the telomer, if present, may be random or blockwise. In one preferrred embodiment of the invention, the telomer segment of formula (19) is composed solely of non-ionic monomer units. In another preferred embodiment of the invention, the telomer radical of formula (19) is composed solely of ionic monomer units, for example solely of cationic monomer units or solely of anionic monomer units. Still another preferred embodiment of the invention is directed to telomer segments of formula (19) comprising nonionic units and ionic units. Suitable non-ionic substituents R 21 and R 21 ' include for example a radical C C 6 -alkyl which is substituted by one or more same or different substituents selected from the group consisting of -OH, Cι-C 4 -alkoxy and -NR22R2 2 '. wherein R 22 and R 22 ' are each independently of another hydrogen or unsubstituted or hydroxy-substituted d-Cβ-alkyl or phenyl; phenyl which is substituted by hydroxy, Cι-C 4 -alkoxy or -NR 22 R 22 '. wherein R 22 and R 2 ' are as defined above; a radical -COOU, wherein U is d-C 2 -alkyl which is unsubstituted or substituted, for example, by hydroxy, C C 4 -alkoxy, -O-Si(CH 3 ) 3 , -NR 22 R 22 ' wherein R 2 and R 2 2' are as defined above, a radical -O-(CH 2 CH 2 O)ι. 2 -Eι wherein E 1 is hydrogen or d-C 6 - alkyl, or a radical -NH-C(O)-O-G, wherein -O-G is the radical of a saccharide with 1 to 8 sugar units or is a radical -O-(CH 2 CH 2 O)ι. 2 -Eι, wherein Ei is as defined above, or U is C 5 - C 8 -cycloalkyl which is unsubstituted or substituted by Cι-C -alkyl or Cι-C -alkoxy, or is unsubstituted or C C -alkyl- or d-C -alkoxy-substituted phenyl or C 7 -Cι 2 -aralkyl; -CONUιU 2 wherein Ui and U are each independently hydrogen, d-d ∑ -alkyl, which is unsubstituted or substituted for example by hydroxy, d-C 4 -alkoxy or a radical -O-(CH 2 CH 2 O)ι- 24 -Eι wherein Ei is as defined above, or Ui and U 2 together with the adjacent N-atom form a five- or six- membered heterocyclic ring having no additional heteroatom or one additional oxygen or nitrogen atom; a radical -OU 3 , wherein U 3 is hydrogen; or d-C 12 -alkyl which is unsubstituted or substituted by -NR 22 R 22 '; or is a radical -C(O)-Cι-C 4 -alkyl; and wherein R 22 and R 22 ' are as defined above; or a five- to seven-membered heterocyclic radical having at least one N- atom and being bound in each case via said nitrogen atom. Suitable anionic substituents R 21 and R 2 ι' include for example d-C 6 -alkyl which is substituted by -SO 3 H, -OSO 3 H, -OPO 3 H 2 and -COOH; phenyl which is substituted by one or more same or different substituents selected from the group consisting of -SO 3 H, -COOH, - OH and -CH 2 -SO 3 H; -COOH; a radical -COOU 4 , wherein U 4 is d-C 24 -alkyl which is substituted for example by -COOH, -SO 3 H, -OSO 3 H, -OPO 3 H 2 or by a radical -NH-C(O)-O- G' wherein G' is the radical of an anionic carbohydrate; a radical -CONU 5 U 6 wherein U 5 is Cι-C 24 -alkyl which is substituted by -COOH, -SO 3 H, -OSO 3 H, or -OPO 3 H 2 and U 6 independently has the meaning of U 5 or is hydrogen or d-Cι 2 -alkyl; or -SO 3 H; or a salt thereof, for example a sodium, potassium, ammonium or the like salt thereof. Suitable cationic substituents R 2 ι and R 2 ι' include Cι-Ci 2 -alkyl which is substituted by a radical -NR 22 R 22 'R 22 " + An " , wherein R 22 , R 22 ' and R 22 " are each independently of another hydrogen or unsubstituted or hydroxy-substituted d-C 6 -alkyl or phenyl, and An " is an anion; or a radical -C(O)OU 7 , wherein U 7 is d-C 24 -alkyl which is substituted by -NR 22 R 22 'R 22 " + An " and is further unsubstituted or substituted for example by hydroxy, wherein R^, R 22 ', R 22 " and An " are as defined above. Suitable zwitterionic substituents R 2i and R 21 ' include a radical -R 23 -Zw, wherein R 23 is a direct bond or a functional group, for example a carbonyl, carbonate, amide, ester, dicarboanhydride, dicarboimide, urea or urethane group; and Zw is an aliphatic moiety comprising one anionic and one cationic group each. The following preferences apply to the hydrophilic substituents R 21 and R 2 ι': (i) non-ionic substituents: Preferred alkyl substituents R 2 ι and R 2 ι' are d-C 4 -alkyl, in particular d-C 2 -alkyl, which is substituted by one or more substituents selected from the group consisting of -OH and -NR 22 R 22 ', wherein R 22 and R 22 ' are each independently of another hydrogen or d-C 4 -alkyl, preferably hydrogen, methyl or ethyl and particularly preferably hydrogen or methyl, for example -CH 2 -NH 2 , -CH 2 -N(CH 3 ) 2 . Preferred phenyl substituents R 21 and R 21 ' are phenyl which is substituted by -NH 2 or N(Cι-C 2 -alkyl) 2 , for example o-, m- or p-aminophenyl. In case that the hydrophilic substituent R 21 or R 2 ' is a radical -COOU, U as optionally substituted alkyl is preferably Cι-C 12 -alkyl, more preferably d-Cβ-alkyl, even more preferably Cι-C 4 -alkyl and particularly preferably d-C 2 -alkyl, each of which being unsubstituted or substituted as mentioned above. In case that the alkyl radical U is substituted by -NR 22 R 22 ', the above-given meanings and preferences apply for R 22 and R 22 '. Examples of suitable saccharide substituents -O-G of the alkyl radical U that is substituted by -NH-C(O)-O-G are the radical of a mono- or disaccharide, for example glucose, acetyl glucose, methyl glucose, glucosamine, N-acetyl glucosamine, glucono lactone, mannose, galactose, galactosamine, N-acetyl galactosamine, fructose, maltose, lactose, fucose, saccharose or trehalose, the radical of an anhydrosaccharide such as levoglucosan, the radical of a glucosid such as octylglucosid, the radical of a sugar alcohol such as sorbitol, the radical of a sugar acid derivative such as lactobionic acid amide, or the radical of an oligosaccharide with a maximum of 8 sugar units, for example fragments of a cyclodextrin, starch, chitosan, maltotriose or maltohexaose. The radical -O-G preferably denotes the radical of a mono- or disaccharide or the radical of a cyclodextrin fragment with a maximum of 8 sugar units. Particular preferred saccharide radicals -O-G are the radical of trehalose or the radical of a cyclodextrin fragment. In case that the alkyl radical U is substituted by a radical -O-(CH 2 CH 2 O)ι. 24 -Eι or -NH-C(O)-O-G wherein -O-G is -O- CH Z CH ∑ O^-E L the number of (CH 2 CH 2 O) units is preferably from 1 to 12 in each case and more preferably from 2 to 8. Ei is preferably hydrogen or d-C 2 -alkyl. U as C 5 -C 8 -cycloalkyl is for example cyclopentyl or preferably cyclohexyl, each of which being unsubstituted or substituted for example by 1 to 3 d-C -alkyl groups. U as C 7 -Cι 2 - aralkyl is for example benzyl. Preferred nonionic radicals -COOU are those wherein U is d-C 6 -alkyl; or C 2 -C 6 -alkyl which is substituted by one or two substituents selected from the group consisting of hydroxy; ; d- C 2 -alkoxy; -O-Si(CH 3 ) 3 ; and -NR 22 R 22 ' wherein R 22 and R 22 ' are each independently of another hydrogen or Cι-C 4 -alkyl; or U is a radical -CH 2 CH 2 -O-(CH 2 CH 2 O) M2 -E I wherein Ei is hydrogen or Cι-C 2 -alkyl; or is a radical -C 2 -C 4 -alkylene-NH-C(O)-O-G, wherein -O-G is the radical of a saccharide. More preferred non-ionic radicals -COOU are those wherein U is Cι-C -alkyl; or C 2 -C 4 -alkyl which is substituted by one or two substituents selected from the group consisting of -OH and -NR 22 R 22 ' wherein R 22 and R 22 ' are each independently of another hydrogen or d-C 2 - aikyl; or a radical -CH 2 CH 2 -O-(CH 2 CH 2 O) M2 -E I wherein Ei is hydrogen or d-C 2 -alkyl; or is a radical -C 2 -C 4 -alkylene-NH-C(O)-O-G wherein -O-G is the radical of a saccharide. Particularly preferred radicals -COOU comprise those wherein U is d-C 2 -alkyl, particularly methyl; or C 2 -C 3 -alkyl, which is unsubstituted or substituted by hydroxy or N,N-di-d-C 2 - alkylamino, or is a radical -C 2 -C 3 -alkylene-NH-C(O)-O-G wherein -O-G is the radical of trehalose or the radical of a cyclodextrin fragment with a maximum of 8 sugar units. Preferred non-ionic substituents -C(O)-NUιU 2 are those wherein Ui and U 2 are each independently of the other hydrogen or C C 6 -alkyl which is unsubstituted or substituted by hydroxy; or Ui and U 2 together with the adjacent N-atom form a heterocyclic 6-membered ring having no further heteroatom or having one further N- or O-atom. Even more preferred meanings of Ui and U 2 , independently of each other, are hydrogen or C C -alkyl which is unsubstituted or substituted by hydroxy; or Ui and U 2 together with the adjacent N-atom form a N-Cι-C 2 -alkylpiperazino or morpholino ring. Particularly preferred non-ionic radicals -C(O)-NYιY 2 are those wherein Y and Y 2 are each independently of the other hydrogen, Cι-C 2 -alkyl or hydroxy-C 1 -C 2 -alkyl; or Yi and Y 2 together with the adjacent N-atom form a morpholino ring. Preferred non-ionic substituents -OU 3 are those wherein U 3 is hydrogen, d-C -alkyl which is unsubstituted or substituted by -NH 2 or -N(Cι-C 2 -alkyl) 2 , or is a group -C(O)C C 2 -alkyl. U 3 is particularly preferred hydrogen or acetyl. Preferred non-ionic heterocyclic substituents R 2 ι and R 2 ι' are a 5- or 6-membered heteroaromatic or heteroaliphatic radical having one N-atom and in addition no further heteroatom or an additional N- or O- heteroatom, or is a 5 to 7-membered lactame. Examples of such heterocyclic radicals are N-pyrrolidonyl, 2- or 4-pyridinyl, 2-methyl pyridin- 5-yl, 2-, 3- Oder 4-hydroxypyridinyl, N-ε-caprolactamyl, N-imidazolyl, 2-methyiimidazol-1-yl, N-morpholiny! or 4-N-methylpiperazin-1-yl, particularly N-morpholinyl or N-pyrrolidonyl. A group of preferred non-ionic substituents R 2 ι and R 2 ι' comprises Cι-C 2 -alkyl, which is unsubstituted or substituted by -OH or -NR 22 R 22 ', wherein R 22 and R 22 ' are each independently of the other hydrogen or Cι-C 2 -alkyl; a radical -COOU wherein U is C C 4 -alkyl; C 2 -C 4 - alkyl which is substituted by -OH, -NR 22 R 22 ' wherein R 22 and R 22 ' are each independently of another hydrogen or Cι-C 2 -alkyl, or U is a radical -C 2 -C 4 -alkylene-NH-C(O)-O-G wherein -O-G is the radical of a saccharide; a radical -C(O)-NUιU 2 , wherein Ui and U 2 are each independently of the other hydrogen or d-C 6 -alkyl which is unsubstituted or substituted by hydroxy, or Ui and U 2 together with the adjacent N-atom form a heterocyclic 6-membered ring having no further heteroatom or having one further N- or O-atom; a radical -OU 3 , wherein U 3 is hydrogen, d-C 4 -alkyl which is unsubstituted or substituted by -NH 2 or -N(Cι-C 2 -alkyl) 2 . or is a group -C(O)d-C 2 -alkyl; or a 5- or 6-membered heteroaromatic or heteroaliphatic radical having one N-atom and in addition no further heteroatom or an additional N-, O- or S-heteroatom, or a 5 to 7-membered lactame. A group of more preferred non-ionic substituents R 21 and R 2 ι' comprises a radical -COOU, wherein U is Cι-C 2 -alkyl, C 2 -C 3 -alkyl, which is substituted by hydroxy, amino or N,N-di-C C 2 - alkylamino, or is a radical -C 2 -C 4 -alkylene-NH-C(O)-O-G wherein -O-G is the radical of trehalose or a cyclodextrin fragment with a maximum of 8 sugar units; a radical -CO-NUιU 2 , wherein Ui and U 2 are each independently of the other hydrogen or C C 4 -alkyl which is unsubstituted or substituted by hydroxy, or Ui and U 2 together with the adjacent N-atom form a N-d-C 2 -alkylpiperazino or morpholino ring; or a heterocyclic radical selected from the group consisting of N-pyrrolidonyl, 2- or 4-pyridinyl, 2-methylpyridin-5-yl, 2-, 3- oder 4- hydroxypyridinyl, N-ε-caprolactamyl, N-imidazolyl, 2-methylimidazol-1 -yl, N-morpholinyl and 4-N-methylpiperazin-1 -yl. A particularly preferred group of non-ionic substituents R 21 and R21' comprises the radicals -COO-Cι-C 2 -alkyi. -COO-(CH 2 ) 2 - 4 -OH, -CONH 2 , -CON(CH 3 ) 2 , -CONH-(CH 2 ) 2 -OH, and -COO(CH 2 ) 2 . 4 -NHC(O)-O-G wherein -O-G is the radical of trehalose. (ii) anionic substituents: Preferred anionic substituents R 2 and R 2 ι' are Cι-C 4 -alkyl, in particular Cι-C 2 -alkyl, which is substituted by one or more substituents selected from the group consisting of -SO 3 H and -OPO 3 H 2 , for example -CH 2 -SO 3 H; phenyl which is substituted by -SO 3 H or sulfomethyl, for example o-, m- or p-sulfophenyl or o-, m- or p-sulfomethylphenyl; -COOH; a radical - COOY 4> wherein U 4 is C 2 -C 6 -alkyl which is substituted by -COOH, -SO 3 H, -OSO 3 H, -OPO 3 H 2 , or by a radical -NH-C(O)-O-G' wherein G' is the radical of lactobionic acid, hyaluronic acid or sialic acid, in particular C 2 -C 4 -alkyl which is substituted by -SO 3 H or - OSO 3 H; a radical -CONU 5 U 6 wherein U 5 is Cι-C 6 -alkyl substituted by sulfo, in particular C 2 - C -alkyl substituted by sulfo, and U 6 is hydrogen, for example the radical -C(O)-NH-C(CH 3 ) 2 -CH 2 -SO 3 H; or -SO 3 H; or a suitable salt thereof. Particular preferred anionic substituents R 2 ι and R 2 ι' are -COOH, -SO 3 H, o-, m- or p-sulfophenyl, o-, m- or p- sulfomethylphenyl or a radical -CONU 5 U 6 wherein U 5 is C 2 -C 4 -alkyl substituted by sulfo, and U 6 is hydrogen. (iii) cationic substituents: Preferred cationic substituents R 2 ι and R 2 ι' are CrC 4 -alkyl, in particular Cι-C 2 -alkyl, which is in each case substituted by -NR R^'R^An " ; or a radical -C(O)OU wherein U 7 is C 2 -C 6 - alkyl, in particular C 2 -C 4 -alkyl, which is in each case substituted by -NR 22 R 22 'R 22 ,,+ An " and is further unsubstituted or substituted by hydroxy. R^, R 22 ' and R^" are each independently of another preferably hydrogen or Cι-C 4 -alkyl, more preferably methyl or ethyl and particularly preferably methyl. Examples of suitable anions An ' are Hal " , wherein Hal is halogen, for example Br " , F, J " or particularly CT, furthermore HCO 3 ' , CO 3 2" , H 2 PO 3 " , HPO 3 2" , PO 3 3' , HSO 4 " , SO 4 2' or the radical of an organic acid such as OCOCH 3 " and the like. A particularly preferred cationic substituent R 2 ι and R 2 ι' is a radical -C(O)OU 7 wherein U 7 is C 2 -C -alkyl, which is substituted by -N(d-C 2 -alkyl) 3 + An ' and is further substituted by hydroxy, and An ' is an anion, for example the radical -C(O)O-CH 2 -CH(OH)-CH 2 -N(CH 3 ) 3 + An " . (iv) zwitterionic substituents -R 23 -Zw: R 23 is a preferably a carbonyl, ester or amide functional group and more preferably an ester group -C(O)-O-. Suitable anionic groups of the moiety Zw are for example -COO " , -SO 3 ' , -OSO 3 " , -OPO 3 H " or bivalent -O-PO 2 ~ - or -O-PO 2 " -O-, preferably a group -COO " or -SO 3 " or a bivalent group -O-PO 2 " -, and in particular a group -SO 3 " . Suitable cationic groups of the moiety Zw are for example a group -NR 22 R 22 'R 22 " + or a bivalent group -NR^R^-, wherein R 22) R 22 ' and R^" are as defined above, and are each independently of the other, preferably hydrogen or Cι-C 6 -alkyl, preferably hydrogen or C C 4 -alkyl and most preferably each methyl or ethyl. The moiety Zw is for example C 2 -C 30 -alkyl, preferably C 2 -Cι 2 -alkyl, and more preferably C 3 - C 8 -alkyl, which is in each case uninterrupted or interrupted by -O- and substituted or interrupted by one of the above-mentioned anionic and cationic groups each, and, in addition, is further unsubstituted or substituted by a radical -OU 8 , wherein U 8 is hydrogen or the acyl radical of a carboxylic acid. U 8 is preferably hydrogen or the acyl radical of a higher fatty acid. Zw is preferably C 2 -Cι 2 -alkyl and even more preferably C 3 -C 8 -alkyl which is substituted or interrupted by one of the above-mentioned anionic and cationic groups each, and in addition may be further substituted by a radical -OU 8 . A preferred group of zwitter-ionic substituents -R 23 -Z corresponds to the formula -C(O)O-(alk"')-N(R 22 ) 2 + -(alk°)-An " or -C(O)O-(alk"")-O-PO 2 " -(O)o.i-(alk"')-N(R 22 ) 3 + wherein R 22 is hydrogen or d-C 6 -alkyl; An " is an anionic group -COO " , -SO 3 \ -OSO 3 " or -OPO3H " , preferably -COO " or -SO 3 ' and most preferably -SO 3 ' , alk 0 is Cι-Cι 2 -alkylene, (alk"") is C 2 -C 24 -alkylene which is unsubstituted or substituted by a radical -OU 8 , U 8 is hydrogen or the acyl radical of a carboxylic acid, and (alk'") is C 2 -C 8 -alkylene. (alk°) is preferably C 2 -C 8 -alkylene, more preferably C 2 -C 6 -alkylene and most preferably C 2 - C 4 -alkylene. (alk"") is preferably C 2 -Cι 2 -alkylene, more preferably C 2 -C 6 -alkylene and particularly preferably C 2 -C 3 -alkylene which is in each case unsubstituted or substituted by hydroxy or by a radical -OU 8 . (alk"') is preferably C 2 -C 4 -alkylene and more preferably C 2 -C 3 - alkylene. R 22 is hydrogen or Cι-C -alkyl, more preferably methyl or ethyl and particularly preferably methyl. A preferred zwitterionic substituent R 2 ι and R 2 is of formula -C(O)O-CH 2 -CH(OU 8 )-CH 2 -O-PO 2 ' -(CH 2 ) 2 -N(CH 3 )3 + , wherein U 8 is hydrogen or the acyl radical of a higher fatty acid. In one embodiment of the invention R 2 ι' may also be a hydrophobic substituent which includes especially those customarily used in the manufacture of contact lenses. Suitable hydrophobic substituents include, without the list being exhaustive -CN, -Cl, C 2 -d 8 -alkyl, d-Cι 8 -haloalkyl, phenyl, Cι-C 6 -alkylphenyl, C 2 -Cι 0 -perfluoroalkyloxycarbonyl or correspondingly partially fluorinated radicals, C 2 -Cι 2 -alkenyl, mono-, di- or poly(alkylsiloxyl), carbazolyl and the like. Examples of underlying hydrophobic vinylic comonomers include acrylonitrile, methacrylonitrile, styrene, chloroprene, vinyl chloride, vinylidene chloride, 1-butene, butadiene, vinyltoluene, trifluoroethyl methacrylate, hexafluoroisopropyl methacrylate, hexafluorobutyl methacrylate, tris-trimethylsilyloxy-silyl-propyl methacrylate, 3-methacryloxy- propylpentamethyldisiloxane and bis(methacryloxypropyl)tetramethyldisiloxane. (Alk") is preferably C 2 -C 8 -alkylene, more preferably C 2 -C 6 -alkylene, even more preferably C 2 -C 4 -alkylene and particularly preferably 1 ,2-ethylene. The alkylene radical (Alk") may be a branched or preferably a linear alkylene radical. T is for example hydrogen or a radical of the chain transfer agent being used for the preparation of the telomer. The total of (m+n) is preferably an integer from 2 to 150, more preferably from 5 to 100, even more preferably from 5 to 75 and particularly preferably from 10 to 50. In a preferred embodiment of the invention n is 0 and m is an integer from 2 to 250, preferably from 2 to 150, more preferably from 5 to 100, even more preferably from 5 to 75 and particularly preferably from 10 to 50. A preferred group of telomer segments of formula (19) are those wherein (Alk") is C 2 -C 6 - alkylene, T is a monovalent group that is suitable to act as a polymerization chain-reaction terminator, m and n are each an integer of from 0 to 100 and the total of (m+n) is from 5 to 100, R 20 and R 20 ' are each independently of the other hydrogen or methyl, and for R 2 ι and R 22 ' each independently of the other the meanings and preferences given before apply. A more preferred group of suitable hydrophilic telomers are those segments of formula (19), wherein (Alk") is C 2 -C 4 -alkylene, T is a monovalent group that is suitable to act as a polymerization chain-reaction terminator, m is an integer from 5 to 100, n is 0, R 20 is hydrogen or methyl, and for R 21 the above given meanings and preferences apply. A particularly preferred embodiment of the invention relates to telomer segments of the formula (19) wherein (Alk") is C 2 -C 4 -alkylene, T is as defined before, R 20 is hydrogen or methyl, n is 0, m is an integer of 5 to 50, and R 21 is a radical -COO-Cι-C 2 -alkyl, -COO- (CH 2 ) M -OH, -CONH 2 , -CON(CH 3 ) 2 , -CONH-(CH 2 ) 2 -OH, , — or -COO(CH 2 ) 2 . 4 -NHC(O)-O-G wherein -O-G is the radical of trehalose. The mean weight average molecular weight of the hydrophilic blocks B may vary within wide limits. A preferred embodiment of the invention relates to prepolymers, particularly to prepolymers for ophthalmic uses, wherein segments B have a mean molecular weight in the range from about 200 to about 10,000, preferably in the range from about 350 to about 5000 and particularly preferably in the range from about 500 to about 1 ,500. Q is, for example, a crosslinkable or polymerizable group Qι or a hydrophilic segment comprising a crosslinkable or polymerizable group such as Q^ Q as a group Qi is, for example, a radical of formula wherein (Alk) is linear or branched Cι-Cι 2 -alkylene, X is -O- or -NH-, Rn is an olefinically unsaturated copolymerisable radical having from 2 to 24 carbon atoms which may be further substituted, and w is the number 0 or 1. Suitable substituents on the olefinic C 2 -C 24 radical Rn are, for example, Cι-C alkoxy, halogen, phenyl or carboxy. Rn is, for example, a radical of formula wherein I is the number 0 or 1 , Rι 2 is hydrogen, Cι-C -alkyl or halogen, each of Rι 3 and Rι independently of the other is hydrogen, d-C -alkyl, phenyl, carboxy or halogen, and Rι 5 is linear or branched Cι-Cι 2 -alkylene or unsubstituted or C C 4 -alkyl- or Cι-C -alkoxy-substitu- ted phenylene or C 7 -Cι 2 -aralkylene. When R 15 is a phenylene radical, it is, for example, unsubstituted or methyl- or methoxy- substituted 1 ,2-, 1 ,3- or 1 ,4-phenylene. Preferably, Rι 5 as a phenylene radical is 1 ,3- or 1 ,4-phenylene. When R 15 is an aralkylene radical, it is, for example, unsubstituted or methyl- or methoxy- substituted benzylene, wherein the methylene group is bonded to the amine nitrogen in each case. Preferably, R 1 5 as an aralkylene radical is the 1 ,3- or 1 ,4-phenylenemethylene radical. R 1 5 is preferably unsubstituted or methyl- or methoxy-substituted phenylene or phenylene- methylene or Cι-Cι 2 alkylene, more preferably 1 ,3- or 1 ,4-phenylene or d-C 6 alkylene, especially Cι-C 2 alkylene and most preferably methylene. I is the number 1 or, preferably, the number 0. Rι 2 is preferably hydrogen, methyl or chlorine and most preferably hydrogen or methyl. Each of R 13 and R M independently of the other is preferably hydrogen, carboxy, chlorine, methyl or phenyl. In a preferred embodiment of the invention, R i3 is hydrogen, chlorine, methyl or phenyl and Rι 4 is hydrogen or carboxy. Most preferably, R13 and Ru are each hydrogen. Examples of suitable radicals Rn are vinyl, 1-methylvinyl, 2-propenyl, allyl, 2-butenyl, o-, m- or p-vinylphenyl, styryl, 2-carboxyvinyl, 2-chloro-2-carboxyvinyl, 1 ,2-dichloro-2-carboxyvinyl, 1 ,2-dimethyl-2-carboxyvinyl and 2-methyl-2-carboxyvinyl. Especially preferred radicals Rn correspond to formula (8) wherein I is 0, Rι 2 is hydrogen or methyl, R 13 is hydrogen, methyl, chlorine or phenyl, in particular hydrogen, and R 14 is carboxy or particularly hydrogen. Other especially preferred radicals R correspond to the above formula (8) wherein I is 1 , Ri 5 is 1 ,3- or 1 ,4-phenylene or d-C 6 -alkylene, especially d-C 2 -alkylene, Rι 2 is hydrogen or methyl and R 13 and R 1 are each hydrogen. (Alk) is preferably Cι-C 4 -alkylene, especially methylene or 1 ,1-dimethylmethylene. One group of suitable radicals L Qι are those wherein Li is a radical of formula (4c) wherein Xi is -NH- or in particular -O-, Qι corresponds to a radical of the above formula (7) wherein w is 0, and for R the above given meanings and preferences apply. A second group of suitable radicals L 1 -Q 1 are those wherein is a radical of formula (4c) wherein Xi is -NH- or in particular -O-, Qι corresponds to a radical of the above formula (7) wherein w is 1 , and for Rn the above given meanings and preferences apply. Still another group of suitable radicals L 1 -Q 1 are those wherein is a radical of formula (4e) wherein Xi is -NH- or in particular -O-, X 2 is -NH-, Q^ corresponds to a radical of the above formula (7) wherein w is 1 , and for Rn the above given meanings and preferences apply. Especially preferred radicals -L 1 -Q 1 correspond to formula or wherein Xi is -O- or -NH-, in particular -O-. Q as a hydrophilic segment comprising a crosslinkable or polymerizable C-C double bond group is, for example a polyoxyalkylene, such as a polyethylene glycol or polypropylene glycol or a block copolymer thereof, a poly(vinylpyrrolidone), poly(hydroxyethylacrylate), poly(hydroxyethylmethacrylate), polyacrylamide, poly(N,N-dimethylacrylamide), poiyacrylic or polymethacrylic acid, a polyacyl alkylene imine, a hydrophilic telomer or a copolymeric mixture of two or more of the above-mentioned polymers which in each case comprises one or more, preferably 1 , ethylenically unsaturated bond and has a weight average molecular weight of, for example, >100. C-C double bond containing hydrophilic segments Q advantageously have a mean molecular weight in the range from about 200 to about 10,000, preferably in the range from about 350 to about 5000 and particularly preferably in the range from about 500 to about 1 ,500. Examples of suitable C-C double bond containing hydrophilic segments Q are a radical of formula -((alk")-O) c -[(CH 2 -CH 2 -O) a -(CHR 6 -CHR 7 -O) b ]-(alk")-L 1 '-Q 2 (5a), C (6a), ■ CH— CH — N R n \ C I (6b), or ■ CH— CH — N- wherein for Li' and Q 2 each the meanings and preferences given above for Li and Qi apply, Q 3 is C 3 -Cι 2 -alkenyl or a radical -(CH 2 )ι. 4 -O-Rι 6 wherein Rι 6 is acryloyl, methacryloyl or a group -C(O)-NH-(CH 2 ) 2 ^-O-C(O)-C(Rι 7 )=CH 2 and R 7 is hydrogen or methyl, Q is a radical of formula O II R— X— (Alk')-X 3 — C— C=CH 2 (9b), H, CH 3 O " R 18 C *3 9 CH 2 (9c), or H, CH 3 O -C=CH, (9d), H, CH, wherein X 3 is -O- or -NR, R is hydrogen or Cι-C 4 -alkyl, X 4 is a group -C(O)-O-, -O-C(O)-NH- or -NH-C(O)-O-, (Alk') is Cι-C 8 -alkylene, e is an integer of 0 or 1 , R 18 is Cι-Cι 2 -alkylene, phenylene or C 7 -Cι 2 -phenylenealkylene, X 5 is -O-, -NH- or -N(Cι-C 4 -alkyl)-, n1 is an integer from 1 to 4, preferably froml to 2, R 20 " independently has the meaning of R 20 , and for R 6 , R 7 , R 8 , R 9 , R 20 , R 20 ', R 2 ι, R 2 ι', T, (alk"), (Alk"), a, b, c, m, n and z each the above-given meanings and preferences apply. Q 3 in formula (6a) is preferably a radical -(CH 2 ) 2 . -O-Rι 6 wherein Rι 6 is acryloyl, methacryloyl or a group -C(O)-NH-(CH 2 ) 2 -O-C(O)-C(Rι 7 )=CH 2 , and R 17 is hydrogen or methyl. Preferred meanings of the variables contained in formulae (9a)-(9d) are: R is preferably methyl, ethyl or, in particular, hydrogen. X 3 in formula (9a) is preferably -O- or -NH-. X 3 in formula (9b) is preferably -NH-. X 3 in formula (9c) is preferably -O-. X is preferably the radical -NH-C(O)-O-. Rι 8 is preferably d-C 6 -alkylene or benzyl and more preferably C C 4 -alkylene or benzyl, and most preferably methyl, ethyl or benzyl. (Alk') is preferably C 2 -C 6 -alkylene and in particular C 2 -C -alkylene. e is preferably the number 1. Some examples of suitable radicals Q are o-, m- or p-vinylbenzyl, allyl, acryloyl-CrC 4 -alkyl, in particular acryloylethyl, methacryloyl-C C 4 -alkyl, in particular methacryloylethyl, acrylamido-Cι-C -alkyl, in particular acryiamidoethyl, methacrylamido-Cι-C 4 -alkyl, in particular methacrylamidoethyl, vinyloxycarbonyl-d-C 4 -alkyl, in particular vinyloxycarbonylmethyl or vinyloxycarbonylethyl, and vinylcarbonyl. Q as a hydrophilic block comprising an ethylenically unsaturated group is preferably linked to A or (alk) by a linking group Li of formula (4a). (alk) is preferably C 2 -Cι 2 -alkylene, more preferably C 3 -Cι 0 -alkylene and most preferably C - C 8 -alkylene, which is in each case unsubstituted or substituted by hydroxy. (alk) is preferably linked to A by a linking group L 3 of formula (4a) or (4c). The amphiphilic block copolymers of the invention wherein t is 0 and Li and L 2 are each a linking group of formula (4a) or (4b) may be prepared , for example, by reacting in any order a compound of formula A - (XιH) p+q (10), about (p+q) molar equivalents of a compound of formula about p molar equivalents of a compound of formula Q - X 2 H (12), and about q molar equivalents of a compound of formula B - X 2 'H (13), each, wherein Y is a group -N=C=O or carboxy or a suitable derivative thereof, for example a group -C(O)OH, -C(O)ORι 9 or -C(O)-OHal wherein R1 9 is, for example, C C 4 -alkyl, phenyl or benzyl and Hal is halogen, in particular bromine or chlorine, X 2 ' independently has the meaning of X 2 , and A, B, Xi, X 2 , p and q are as defined above. For example, the compounds of formulae (12) and (13) may be first reacted with about one molar equivalent of a compound of formula (11) each, and the intermediates obtained are then reacted with the compound of formula (10). Another synthetic route comprises first reacting a compound of formula (10) with a compound of formula (11), and the intermediate obtained is then reacted with a mixture of the compounds of formulae (12) and (13). Where the compound of formula (11) is a carboxylic acid or a derivative thereof, e.g. a carboxylic acid halide, the reaction thereof with the components of formulae (10), (12) and (13), respectively, can be carried out under the conditions that are customary for ester, thioester, or amide formation, for example at temperatures of, for example, from -40 to 80°C, preferably from 0 to 50°C and most preferably from 0 to 25°C, in a dipolar aprotic solvent, e.g. tetrahydrofuran, dioxane, DMSO or an aprotic solvent as mentioned below, or in a mixture of water and one of the mentioned solvents, in the presence of a base, e.g. an alkali metal hydroxide, and, where applicable, in the presence of a stabiliser. Suitable stabilisers are, for example, 2,6-dialkylphenols, hydroquinone derivatives, e.g. hydroquinone or hydroquinone monoalkyl ethers, or N-oxides, e.g. 4-hydroxy-2,2,6,6- tetramethyl-piperidin-1-yl. The reaction times may vary within wide limits, a period of, for example, from 30 minutes to 12 hours, preferably from 1 to 6 hours and especially from 2 to 3 hours, generally having been found practicable. Where the compound of formula (11) is an isocyanate, the reaction thereof with the components of formulae (10), (12) and (13), respectively, can be carried out under the conditions that are customary for the formation of urethanes or ureas. In case of urethane formation it is advantageously to perform the reaction in an inert solvent. Amines of the formula (10), (12) and (13) may be reacted with the diisocyanate of formula (11) also in an aqueous medium. It is especially advantageous to use diisocyanates having isocyanate groups of differing reactivity since the formation of isomers and diadducts can thereby be substantially suppressed. The differing reactivity can be brought about, for example, by steric hindrance. Suitable inert solvents for the reaction of the compounds of formulae (10), (12) or (13) with a compound of formula (11 ) are aprotic, preferably polar, solvents, for example hydrocarbons (petroleum ether, methylcyclohexane, benzene, toluene, xylene), halogenated hydrocarbons (chloroform, methylene chloride, trichloroethane, tetrachloroethane, chlorobenzene), ethers (diethyl ether, dibutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dioxane), ketones (acetone, dibutyl ketone, methyl ethyl ketone, methyl isobutyl ketone), carboxylic acid esters and lactones (ethyl acetate, butyrolactone, valerolactone), alkylated carboxylic acid amides (N,N-dimethylacetamide, N-methylpyrrolidone), nitriles (acetonitrile), sulfones and sulfoxides (dimethyl sulfoxide, tetramethylenesulfone). Polar solvents are preferably used. The reaction temperature may be, for example, from -40 to 200°C. When catalysts are used, the temperatures may advantageously be in the range of from 0 to 50°C, preferably at room temperature. Suitable catalysts are, for example, metal salts, such as ferric chloride or alkali metal salts of carboxylic acids, tertiary amines, for example (Cι-C 6 alkyl) 3 N (tri- ethylamine, tri-n-butylamine), N-methylpyrrolidine, N-methylmorpholine, N,N-dimethylpi- peridine, pyridine and 1 ,4-diaza-bicyclooctane. Tin salts have been found to be especially effective, especially alkyltin salts of carboxylic acids, for example dibutyltin dilaurate and tin dioctoate. The isolation and purification of the compounds prepared is carried out according to known methods, for example by means of extraction, crystallisation, recrystallisation or chromatographic purification methods. The amphiphilic block copolymers of the invention wherein t is 0 and Li and L 2 are each a linking group of formulae (4c), (4d) or (4e) may be prepared , for example, by reacting a compound of the formula A - (Y) P+q (10a) with about p molar equivalents of a compound of the above formula (12) and q molar equivalents of a compound of formula (13), or by reacting a compound of the above formula (10) with about p molar equivalents of a compound of formula Q - Y (12a) and about q molar equivalents of a compound of formula B - Y (13a), wherein A, B, Q, Y, p and q each have the above-mentioned meaning. The reaction of the components of formulae (10a) and (12) and (13) or (10) and (12a) and (13a), respectively, can be carried out under the conditions that are customary for ester, thioester, amide, urethane or urea formation, for example as outlined above. The amphiphilic block copolymers of the invention wherein p and q are each 0 and Li and L 2 are each a linking group of formula (4a), (4b), (4c) or (4e) may be prepared , for example, by reacting a compound of formula ■ L g — (alk) (X.H), P 1+q1 (14) J t with (i) about p1 molar equivalents of a compound of formula (12a) or the reaction product of a compound of formula (11) and (12); and (ii) about q1 molar equivalents of a compound of formula (13a) or the reaction product of a compound of formula (11) and (13), wherein A, L 3 , X^ (alk), p1 and q1 are each as defined above. The reactions can be carried out under the conditions that are customary for ester, thioester, amide, urethane or urea formation, for example as outlined above. A linking group Li or L 2 of formula (4d) in the above amphiphilic block copolymers may be obtained, for example, by reacting a compound which is analogous to the compound of formula (14) but contains a carboxy group or an above-mentioned derivative thereof with a compound of formula (12) or (13). The amphiphilic block copolymers of the invention wherein p and q are each 0, Li is a linking group of formula (4c) or (4e), L 2 is a linking group of formula (4d) and L 3 is a linking group of formula (4c) may be prepared , for example, by reacting a dilactone, for example a bis-β-lactone, bis-γ-lactone or bis-δ-lactone such as glucaro-1 ,4:3,6-dilactone or mannaro- 1 ,4:3,6-dilactone, in any order with a compound of formulae (10), (12a) and (13) each. The compounds of formula (10), (10a), (11), (12), (12a), (13) and (13a) are known or may be prepared according to processes known in the art. For example, the compounds of formula (13) or (13a), wherein B is a telomer segment are known from WO99/57581. The compounds of formula (14) are known or may be prepared according to processes known in the art, for example by reacting a compound A-(XiH), with a compound YrfalkMXi'HJpi+qi or wherein Xi' independently has the meaning of Xi, Yi is carboxy or an above-mentioned derivative thereof, and Xi, (alk), p1 und q1 each have the above-mentioned meaning. The molecular weight of the copolymers of the invention is, within wide limits, not critical. Preferably, however, the prepolymer has a weight average molecular weight of from approximately 1400 to 200000, preferably from 2000 to 100000 and more preferably from 2500 to 50000 and most preferably from 3000 to 25000. The amphiphilic block copolymers of formula (1) are crosslinkable, but are uncrosslinked or, at least, substantially uncrosslinked; in addition, they are stable, that is to say spontaneous crosslinking as a result of homopolymerisation does not take place. The amphiphilic block copolymers of formula (1) according to the invention are crosslinkable in a controlled and extremely effective manner, especially by photo-crosslinking. The present invention further relates, therefore, to a polymer that can be obtained by photo- crosslinking of a amphiphilic block copolymers of formula (1), in the presence or, preferably, in the absence of an additional vinyl comonomer. These crosslinked polymers are water- insoluble. In the photo-crosslinking, a photoinitiator capable of initiating free-radical crosslinking is suitably added. Examples thereof will be familiar to the person skilled in the art, suitable photoinitiators that may specifically be mentioned being benzoin methyl ether, 1-hydroxy- cyclohexylphenyl ketone, Darocure 1173 or Irgacure types. The crosslinking can then be brought about by actinic radiation, e.g. UV light, or ionising radiation, e.g. gamma rays or X-rays. The amount of photoinitiator may be selected within wide limits, an amount of up to 0.05 g/g of polymer and especially of up to 0.01 g/g of polymer having proved beneficial. The amphiphilic block copolymers of formula (1 ) is introduced into the crosslinking process preferably in pure form, particularly substantially free from undesired constituents, such as, for example, free from monomeric, oligomeric or polymeric starting compounds used for the preparation of the copolymer, and/or free from secondary products formed during the preparation of the copolymer. Said copolymers in pure form are obtained advantageously by previously purifying them in a manner known per se, for example by precipitation with a suitable solvent, filtration and washing, extraction in a suitable solvent, dialysis, reverse osmoses (RO) or ultrafiltration, reverse osmoses and ultrafiltration being especially preferred. The preferred purification processes for the copolymers of the invention, reverse osmoses and ultrafiltration, can be carried out in a manner known p_er se. It is possible for the ultrafiltration and reverse osmoses to be carried out repeatedly, for example from two to ten times. Alternatively, the ultrafiltration and reverse osmoses can be carried out continuously until the selected degree of purity is attained. The selected degree of purity can in principle be as high as desired. The copolymers of formula (1 ) may be crosslinked, for example, in form of a solution or a mesophase. One embodiment of the invention relates to the photo-polymerisation of the block copolymers of the invention in solution, preferably in one or more different organic solvents. Suitable solvents are in principle all solvents that dissolve the polymers according to the invention and an optional vinyl comonomer which may be additionally used, e.g. alcohols, such as C C 6 - alkanols, e.g. n- or iso-propanol, ethanol or methanol, carboxylic acid amides, such as dimethylformamide, or dimethyl sulfoxide, and mixtures of suitable solvents, e.g. mixtures of water with an alcohol, e.g. a water/propanol, water/ethanol or a water/methanol mixture. According to this embodiment of the invention, the photo-crosslinking is preferably effected from a solution comprising (i) one or more prepolymers according to the invention which can be obtained as a result of the preferred purification step, ultrafiltration, (ii) one or more solvents selected from the group consisting of a C C 6 - alkanol, a carboxylic acid amide, dimethyl sulfoxide and water, and optionally (Hi) an additional vinyl comonomer. For example, photo-crosslinking of the block copolymers is carried out in ethanol or n- or iso- propanol. The vinyl comonomer that can additionally be used according to the invention in the photo- crosslinking may be hydrophilic or hydrophobic or may be a mixture of a hydrophobic and a hydrophilic vinyl monomer, or may be a crosslinker. Suitable vinyl monomers include especially those which are customarily used in the manufacture of contact lenses. The expression "hydrophilic vinyl monomer" is understood to mean a monomer that typically produces as homopolymer a polymer that is water-soluble or capable of absorbing at least 10 % by weight water. Analogously, the expression "hydrophobic vinyl monomer" is understood to mean a monomer that typically produces as homopolymer a polymer that is water-insoluble or capable of absorbing less than 10 % by weight water. The proportion of vinyl comonomers, if used, is preferably from 0.5 to 80 units per copolymer of formula (1 ), especially from 1 to 30 units of vinyl comonomer per copolymer unit of formula (1) and most preferably from 5 to 20 units per copolymer of formula (1). It is also preferred to use a hydrophobic vinyl comonomer or a mixture of a hydrophobic vinyl comonomer with a hydrophilic vinyl comonomer, the mixture containing at least 50 % by weight of a hydrophobic vinyl comonomer. In that manner, the mechanical properties of the polymer can be improved without the water content being appreciably reduced. In principle, however, both conventional hydrophobic vinyl comonomers and conventional hydrophilic vinyl comonomers are suitable for copolymerisation with a prepolymer of formula (1). Suitable hydrophobic vinyl comonomers include, without the following being an exhaustive list, Cι-Cι 8 alkyl acrylates and methacrylates, C 3 -d 8 alkylacrylamides and -methacrylamides, acrylonitrile, methacrylonitrile, vinyl-C Cι 8 alkanoates, C 2 -Cι 8 alkenes, C 2 -Cι 8 haloalkenes, styrene, d-C 6 alkylstyrene, vinyl alkyl ethers in which the alkyl moiety has from 1 to 6 carbon atoms, C 2 -Cι 0 perfluoroalkyl acrylates and methacrylates or correspondingly partially fluorinated acrylates and methacrylates, C 3 -C 12 perfluoroalkyl-ethyl-thiocarbonylaminoethyl acrylates and methacrylates, acryloxy- and methacryloxy-alkylsiloxanes, N-vinylcarbazole, Cι-Cι 2 alkyl esters of maleic acid, fumaric acid, itaconic acid, mesaconic acid and the like. Preferred are, for example, d-C 4 alkyl esters of vinylically unsaturated carboxylic acids having from 3 to 5 carbon atoms or vinyl esters of carboxylic acids having up to 5 carbon atoms. Examples of suitable hydrophobic vinyl comonomers include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, styrene, chloroprene, vinyl chloride, vinylidene chloride, acrylonitrile, 1-butene, butadiene, methacrylonitrile, vinyltoluene, vinyl ethyl ether, perfluorohexylethyl- thiocarbonylaminoethyl methacrylate, isobomyl methacrylate, trifluoroethyl methacrylate, hexafluoroisopropyl methacrylate, hexafluorobutyl methacrylate, tris-trimethylsilyloxy-silyl- propyl methacrylate, 3-methacryloxypropylpentamethyldisiloxane and bis(methacryloxypro- pyl)tetramethyldisiloxane . Suitable hydrophilic vinyl comonomers include, without the following being an exhaustive list, hydroxy-substituted lower alkyl acrylates and methacrylates, acrylamide, methacryl- amide, lower alkylacrylamide and -methacrylamide, ethoxylated acrylates and methacrylates, hydroxy-substituted lower alkylacrylamides and methacrylamides, hydroxy-substituted lower alkyl vinyl ethers, sodium ethylenesulfonate, sodium styrenesulfonate, 2-acrylamido- 2-methylpropanesulfonic acid, N-vinylpyrrole, N-vinylsuccinimide, N-vinylpyrrolidone, 2- or 4- vinylpyridine, acrylic acid, methacrylic acid, amino- (the term "amino" also including quaternary ammonium), mono-lower alkylamino- or di-lower alkylamino-lower alkyl acrylates and methacrylates, allyl alcohol and the like. Preferred are, for example, hydroxy-substituted C 2 -C 4 alkyl (meth)acrylates, five- to seven-membered N-vinyl lactams, N,N-di-Cι-C alkyl- (meth)acrylamides and vinylically unsaturated carboxylic acids having a total of from 3 to 5 carbon atoms. Examples of suitable hydrophilic vinyl comonomers include hydroxyethyl methacrylate, hydroxyethyl acrylate, acrylamide, methacrylamide, dimethylacrylamide, allyl alcohol, vinyl- pyridine, vinylpyrrolidine, glycerol methacrylate, N-(1 ,1-dimethyl-3-oxobutyl)-acrylamide and the like. Preferred hydrophobic vinyl comonomers are methyl methacrylate and vinyl acetate. Preferred hydrophilic vinyl comonomers are 2-hydroxyethyl methacylate, N-vinylpyrrolidone and acrylamide. Most preferably, the crosslinking of the copolymers of formula (1) is carried out in the absence of a vinylic comonomer. According to another embodiment of the invention, the copolymers of formula (1) are previously converted into an aqueous mesophase, for example into a liquid crystalline phase, which is at least partly bicontinuous, and the mesophase is then subjected to photocrosslinking. The preparation and crosslinking of a suitable mesophase composition may be carried out as disclosed in PCT patent application WO 99/12059. The solutions or mesophases comprising a block copolymer of formula (1 ) may be processed in a manner known perse to form moldings, especially contact lenses, for example by carrying out the photo-crosslinking of the copolymers of the invention in a suitable mold, in particular a contact lens mold. For example, the solution or mesophase is introduced into an opthalmic mold in a manner known per se, such as, especially, by conventional metering in, for example by dropwise introduction or by extrusion. Suitable molds are generally customary contact lens molds as known in the state of the art. Thus, the contact lenses according to the invention can be manufactured, for example, in a manner known per se, for example in a conventional "spin-casting mold", as described, for example, in US-A-3408 429, or by the so-called Full-Mould process in a static mold, as described, for example, in US-A-4347198. Appropriate molds are made, for example, from polypropylene. Quartz, sapphire glass and metals, for example, are suitable materials for re-usable molds. The crosslinking can be triggered in the mold, for example by actinic radiation, such as, for example, UV light, or by ionising radiation, such as, for example, gamma radiation, electron radiation or X radiation. The crosslinking can where appropriate also be triggered thermally or electrochemically. Attention is drawn to the fact that the photocrosslinking can be carried out in a very short time, for example in < 60 minutes, preferably < 20 minutes, more preferably < 5 minutes even more preferably in < 1 minute, especially in up to 30 seconds, especially preferably, as disclosed in the examples. The opening of the mold such that the molding can be removed from the mold can be carried out in a manner known per se. The moldings obtainable from the block copolymers of formula (1) are preferably at least partly bicontinuous, that is to say the moldings have at least two partly bicontinuous phases, for example an oxygen-permeable and an ion-permeable phase, which are intermingled. A "phase", as used herein, refers to a region of substantially uniform composition which is a distinct and physically separate portion of a heterogeneous polymeric material. However, the term "phase" does not imply that the material described is a chemically pure substance, but merely that certain bulk properties differ significantly from the properties of another phase within the material. Thus, with respect to the polymeric components of an ophthalmic molding such as a lens, an ion-permeable phase refers to a region composed of essentially only ion-permeable polymer (and water, when hydrated), while an oxygen-permeable phase refers to a region composed of essentially only oxygen-permeable polymer (and perhaps a small amount of water, when hydrated). "Bicontinuous phases" , as used herein, refers to at least two regions, each of substantially uniform composition which differs from the other, and each of which exhibiting its individual properties. With respect to ophthalmic moldings such as contact lenses it has been found that it is highly desirable to have bicontinuous phases of an oxygen-permeable polymer and an ion-permeable polymer which provide the lens with two continuous pathways or sets of continuous pathways extending from the inner surface of the lens to the outer surface of the lens. Said at least two continuous pathways ensure that the lens material has both a high oxygen transmissibility and ion or water permeability. The invention further relates, therefore, to moldings that comprise or, preferably, substantially consist of a crosslinked block copolymer of formula (1 ). Further examples of moldings of the invention, apart from contact lenses, are biomedical or special ophthalmic moldings, e.g. intraocular lenses, artificial cornea, eye dressings, moldings for use in surgery, such as heart valves, artificial arteries or the like, and films or membranes, e.g. membranes for controlling diffusion, photo-structurable films for information storage, or photoresist materials, e.g. membranes or moldings for etch resists or screen print resists. If the molding manufactured according to the invention is a contact lens and the latter has been manufactured under solventless conditions from a previously purified prepolymer of the invention, then it is normally unnecessary for the removal of the molding to be followed by purification steps, e.g. extraction, because the prepolymers used do not contain any undesired low-molecular-weight constituents; consequently, the crosslinked product also is free or substantially free of such constituents and subsequent extraction can be dispensed with. The contact lens can accordingly be converted into a ready-for-use contact lens directly in conventional manner by hydration. Suitable forms of hydration capable of producing ready-for-use contact lenses with a wide variety of water contents are known to the person skilled in the art. The contact lens is swelled, for example, in water, in an aqueous salt solution, especially in an aqueous salt solution having an osmolarity of approximately from 200 to 450 milliosmol in 1000 ml (unit: mosm/l), preferably approximately from 250 to 350 mosm/l and especially approximately 300 mosm/l, or in a mixture of water or an aqueous salt solution with a physiologically tolerable polar organic solvent, for example glycerol. Swelling of the prepolymer in water or in aqueous salt solutions is preferred. The aqueous salt solutions used for the hydration are advantageously solutions of physiologically tolerable salts, such as buffer salts customary in the field of contact lens care, e.g. phosphate salts, or isotonising agents customary in the field of contact lens care, such as, especially, alkali metal halides, e.g. sodium chloride, or solutions of mixtures thereof. An example of an especially suitable salt solution is a synthetic, preferably buffered, lachrymal fluid that has been matched to natural lachrymal fluid with regard to pH value and osmolarity, e.g. an unbuffered or preferably buffered, for example phosphate buffer-buffered, sodium chloride solution the osmolarity and pH value of which correspond to the osmolarity and pH value of human lachrymal fluid. The hydration fluids defined above are preferably pure, that is to say free or substantially free of undesired constituents. Most preferably, the hydration fluid is pure water or a synthetic lachrymal fluid as described above. If the molding manufactured according to the invention is a contact lens and the latter has been manufactured from an aqueous mesophase of a previously purified copolymer of the invention, the crosslinked product also will not contain any troublesome impurities. There is normally no need, therefore, for subsequent extraction. Since the crosslinking is carried out in an aqueous medium, there is also no need for subsequent hydration. In accordance with an advantageous embodiment, therefore, the contact lenses obtainable by this process are distinguished by the fact that they are suitable for use as intended without extraction or hydration. The expression "use as intended" is understood in this context to mean especially that the contact lenses can be inserted into the human eye. The copolymers of the invention are especially suitable for the manufacture of mass- produced articles, such as, for example, contact lenses that are worn for a short time, for example for a month, a week or just one day, and are then replaced by new lenses. This is in particular because contact lenses prepared from a mesophase of the copolymers can be used for their intended use without subsequent treatment steps, such as extraction or hydration. The copolymers of the invention are further useful for the manufacture of biomedical devices of all kinds, for example ophthalmic moldings such as intraocular lenses or artificial cornea, wound healing dressings, eye bandages, materials for the sustained release of an active compound such as a drug delivery patch, moldings that can be used in surgery, such as heart valves, vascular grafts, catheters, artificial organs, encapsulated biologic implants, e.g. pancreatic islets, materials for prostheses such as bone substitutes, or moldings for diagnostics, membranes or biomedical instruments or apparatus. In addition, biomedical devices, for example ophthalmic moldings such as in particular contact lenses obtainable according to the invention have a range of unusual and extremely advantageous properties and are therefore suited to extended periods of wear (true extended wear, i.e., seven days or more). Among these properties are, for example, their excellent compatibility with the human cornea and with tear fluid, which is based on a balanced ratio between water content, oxygen permeability, ion permeability and mechanical and absorptive properties. In particular, moldings obtainable from a block copolymer of the invention do have a high surface wettability which can be demonstrated by their contact angles, their water retention and their water-film break up time or tear film break up time (TBUT). The TBUT plays an particularly important role in the field of ophthalmic devices such as contact lenses. Thus the facile movement of an eyelid over a contact lens has proven important for the comfort of the wearer; this sliding motion is facilitated by the presence of a continuous layer of tear fluid on the contact lens, a layer which lubricates the tissue/lens interface. An increased wettability of the surface furthermore contributes substantially to low microbial adhesion and resistance to deposit formation. The above outlined properties of the novel copolymers impart a high comfort and the absence of irritation and allergenic effects to biomedical moldings derived therefrom. Owing to their favourable permeability properties with respect to gases (CO 2 and O 2 ), various salts, nutrients, water and diverse other components of tear fluid, the contact lenses prepared according to the process of the invention have no effect, or virtually no effect, on the natural metabolic processes in the cornea. Furthermore, the contact lenses obtainable according to the process are optical clear and transparent, have a high shelf life and good mechanical properties, for example concerning the modulus of elasticity, elongation at break or dimensional stability. All of the advantages mentioned above, in particular those concerning the surface wettability, apply to moldings derived from an amphiphilic block copolymer of the invention per se, that is to say without any subsequent surface treatment, e.g. coating. The block copolymers of the invention thus may be processed directly to biomedical moldings, in particular ophthalmic moldings, without any subsequent surface treatment, e.g. coating, whereas known polymeric materials in general have to be coated with an hydrophilic coating in order to be useful as a biomedical molding that comes in direct contact with the human body. The above-mentioned advantages apply, of course, not only to ophthalmic moldings such as contact lenses but also to other moldings of the invention. The sum of the various advantageous aspects in the manufacture of the moldings of the invention results in the moldings of the invention being especially suitable as mass-produced articles, such as, for example, contact lenses that are worn for a short period and then replaced by new lenses. In the Examples which follow, amounts are by weight, unless specified otherwise, and temperatures are given in degrees Celsius. Dynamic contact angle measurements are obtained using the dynamic Wilhelmy plate method, that is the wetting force on the solid is measured as the solid is immersed in or withdrawn from a liquid of known surface tension. Example 1 : a) 11.8g (15.5 mmol) poly(ethyleneglycol) mono-methyl ether, M n 750(PEG750) are dissolved in 13.8g anhydrous dichloroethane (DCE) in a round-bottomed flask. The PEG750 is dried by refluxing the water/DCE azeotrope through molecular sieves in a Soxhlet funnel. After drying, the contents of the flask is cooled, and 10.2g (45.8 mmol) isophoronediisocyante (IPDI) are then added to the flask, along with 100 mg dibutyltin dilaurate (DBTDL). The contents are mixed overnight at room temperature. The solution is poured into a separatory funnel and the excess IPDI extracted with anhydrous hexane. The waxy-liquid PEG(750)-IPDI product is drained into a RBF and solvent removed under vacuum. The product is stored under vacuum over a weekend, then under nitrogen. (b) In a three-necked round-bottomed flask are dissolved 8.0g (1.4 mmol) of the compound of formula wherein Q * is a radical -O-C(O)-NH-(CH 2 ) 2 -O-C(O)-C(CH 3 )=CH 2 (synthesis see PCT application WO 96/36890) in 30g anhydrous dichloroethane. To this solution are added 4.1 g (4.1 mmol) of the PEG(750)-IPDI. The flask is equipped with a condenser, a thermometer, stir bar, and heating mantle. The mixture is stirred and heated to 45°C. DBTDL catalyst is added, and dry air is infused through the system. After 7 days, no isocyanate peak is visible in the IR, and the solution is then cooled. The solvent is removed via rotary evaporation to yield 10.2g of a product corresponding to the above formula (15), wherein 3 hydroxy groups have been substituted by a radical of formula c) 0.8109g of the product obtained according to step b) are mixed with 0.2g water containing 0.01 % of a photoinitiator (Darocur ® 2959). This mixture is centrifuged, refrigerated overnight, mixed, and recentrifuged until the formulation looks homogeneous and transparent. This formulation is cast on quartz plates that had been soaked overnight in KOH/isopropanol,, rinsed with ethanol, then rinsed with purified water and air dried. The films are cured for 90 seconds under a UV lamp, and extracted with an isopropanol/water mixture. Dynamic contact angle measurements are obtained which indicate a high surface wettability of the films. Example 2 : a) 15.0g (7.8 mol) poly(ethyleneglycol) mono-methyl ether, M n 1900 (PEG1900) is dissolved in 20g anhydrous dichloromethane in a round-bottomed flask. The PEG1900 is dried by refluxing the water/ dichloromethane azeotrope through molecular sieves in a Soxhlet funnel. After drying, the contents of the flask are cooled, and 5.3g (24.0 mmol) isophoronediisocyante (IPDI) are added to the flask, along with 100 mg dibutyltin dilaurate (DBTDL). The contents are mixed over the weekend at room temperature. The solution is poured into a separatory funnel and the excess IPDI extracted with anhydrous hexane. The PEG-IPDI product is drained into a RBF and solvent removed under vacuum. The product is stored under vacuum. b) In a round-bottomed flask are dissolved 5.03g (0.13 mmol) of a compound of formula in 10.4g anhydrous dichloroethane (DCE). To this solution are added 1.9g (1.9 mmol) of the PEG(1900)-IPDI product according to step a) dissolved in 10.2g anhydrous DCE. The mixture is stirred at room temperature under nitrogen for 3.5 hours. Then 0.26g (1.7 mmol) of isocyanatoethyl methacrylate are added to the mixture, which is stirred under infused dry air a few hours, until the isocyanate peak is no longer visible in the IR. The solvent is then removed via rotary evaporation to yield a product of the above formula (17), wherein about 35 % of the amino groups are substituted by a radical of formula and the remaining amino groups are substituted by a radical -O-C(O)-NH-(CH 2 ) 2 -O-C(O)-C(CH 3 )=CH 2 . c) 1.51 g of the product obtained according to step b) are mixed with 1.51 g ethanol and 7.5 mg of a photoinitiator (Darocur ® 1 173). This mixture is stirred to dissolve, degassed, and cast in a dry box on quartz plates that has been soaked overnight in KOH/isopropanol,, rinsed with ethanol, then rinsed with purified water and air dried. The flats are cured for 15 minutes under a UV lamp, and extracted with an isopropanol/water mixture. Dynamic contact angle measurements are obtained which indicate a high surface wettability of the flats. Example 3 : (a)11.8g (15.5 mmol) poly(ethyleneglycol) mono-methyl ether (PEG750) are dissolved in 13.8g anhydrous dichloroethane (DCE) in a round-bottomed flask. The PEG750 is dried by refluxing the water/DCE azeotrope through molecular sieves in a Soxhlet funnel. After drying, the contents of the flask are cooled, and 10.2g (45.8 mmol) isophoronediisocyanate (IPDI) are added to the flask, along with 100 mg dibutyltin dilaurate (DBTDL). The contents are mixed overnight at room temperature. The solution is poured into a separatory funnel and the excess IPDI extracted with anhydrous hexane. The waxy-liquid PEG(750)-IPDI product is drained into a RBF and solvent removed under vacuum. The product is stored under vacuum over a weekend, then under nitrogen. b) To a three-necked round-bottomed flask are added 0.87g (4.88 mmol) D(+) gluconic acid-δ-lactone, and 21 ml anhydrous tetrahydrofuran. The flask is equipped with a condenser, a thermometer, stir bar, and heating mantle. An addition funnel containing 10.00g (0.26 mmol) of the compound of formula (17) according to Example 2 is also attached, and dry nitrogen is infused through the system. The contents of the flask are heated to 38°C. The solution of the compound of formula (17) is added dropwise to the stirring gluconolactone solution. The reaction is stirred at 38°C overnight. The mixture is then cooled and stirred at room temperature over the weekend. The solvent is removed under vacuum. There are obtained 10.59g of a product according to formula (17) wherein the amino groups are each substituted by a radical of formula -NH-C(O)-CH(OH)-CH(OH)- CH(OH)-CH(OH)-CH 2 -OH. c) 4.00g (0.094 mmol) of the product obtained according to step (b) are weighted into a three-necked round-bottomed flask , along with 25.59g tetrahydrofuran. Next, 1.30g (1.32 mmol) PEG(750)-IPDI obtained according to step a) and 0.07g (0.45 mmol) isocyanatoethyl methacrylate are added to the flask, and the mixture stirred. The flask is placed atop a stir plate and equipped with heating mantle, condenser, and thermometer. Dry air is infused throught the system. The reactants are brought to 41 °C, and 100 mg dibutyltin dilaurate are added to the reaction mixture. The mixture is stirred at 41 °C over the weekend. The mixture is then cooled and the solvent removed under reduced pressure. 5.30g of a clear, crystalline compound corresponding to formula (17) wherein the amino groups are each substituted by a radical of formula -NH-C(O)-CH(OH)-CH(OH)-CH(OH)-CH(OH)-CH 2 -OH and about 13 % of the hydroxy groups are substituted by a radical of formula and about 4 % of the hydroxy groups are substituted by a radical of formula 9 o O-C — NH-(CH 2 ) 2 -O— C— C=CH 2 CH 3 are recovered. d) 1.1g of the product obtained according to step c) are mixed with 1.1g ethanol and 9.4mg of a photoinitiator (Darocur ® 1173). This formulation is cast on quartz plates that have been soaked overnight in KOH/isopropanol„ rinsed with ethanol, then rinsed with purified water and air dried. The films are cured for 90 seconds under a UV lamp, and extracted with an isopropanol/water mixture. Dynamic contact angle measurements are obtained which indicate a high wettability of the films obtained. Example 4: A 50 ml addition funnel containing 1.Og of the compound of formula (M w ~1500, synthesis from HO-(CH 2 CH 2 N[C(O)CH 3 ])p-CH 2 -C 6 H 5 -CH=CH 2 ) prepared according to S. Kobayashi et al., Polymer Bulletin 13, p 447-451 (1985) and isophorone diisocyanate) and and 1.Og of the compound of formula (Mw~1300, synthesis from isophorone diisocyanate and HO-(CH 2 CH 2 N[C(O)CH 3 ]) p -CH 3 in 10.1 g dry methylene chloride is placed atop a 100 ml round-bottomed flask, equipped with a stir bar and containing 3.0g of the distilled compound of formula H 3 C H 3 C CH, CH, H 3 C— Si-hO— Si- -O-Si- -O-Si — CH, (17a), H 3 C H 3 C CH, (CH 2 ) 3 NH, Mw about 10000, and 10.2g dry methylene chloride. The flask is placed atop a stir plate, and a septum placed in the add-funnel neck. Stirring is started and addition of the polymethyl oxazoline materials starts. The addition takes 40 minutes, after which the mixture is stirred an additional 4 hours at room temperature. One drop of DBTDL is added to the reaction mixture, which is stired an additional hour. The solvent is then removed via rotary evaporation. The macromer obtained above is formulated 68.62% in water containing 0.5% of a photoinitiator (Irgacure ® 2959). It is centrifuged and stirred. The formulation is cast on quartz plates, and cured for 60 seconds. Thereafter the flats are pealed off the quartz plates, placed in water and autoclaved. Dynamic contact angle measurements are obtained which indicate a high wettability of the films obtained. Comparative Example: The manufacture of the molding above is repeated but using 2g of the compound of formula (18a) instead of the mixture of 1 g each of a compound of formula (18a) and (18b). Dynamic contact angle measurements are obtained which indicate a considerable decrease in wettability compared to the molding obtained with the mixture of compounds (18a) and (18b). Example 5: (5.1) Synthesis of a bis-gluconamido-functional polydimethylsiloxane. A 1 liter three-necked round bottom flask equipped with a magnetic stir bar, internal thermometer, and a Soxhlet-extractor filled with molecular sieves (4 angstroms pore width) and a drying tube filled with Drierite™ is charged with 200 g (0.43 mEq/g NH 2 -groups) aminopropyl-terminated polydimethylsiloxane and 300 mL THF. The solution is heated to 65°C overnight, eliminating traces of water by passing the solvent repeatedly through the bed of molecular sieves. After cooling to room temperature the next morning, Karl-Fischer titration indicates 50 ppm residual water. 15.3 g (86 mmol) D-(+)-gluconic acid-delta-lactone are suspended in 100 mL dry THF and the suspension is added to the amino-PDMS solution. The mixture was heated to 40°C for two days. The turbid suspension gradually transforms to a clear solution. The course of the reaction can be controlled by thin layer chromatography. After completion the solution is filtered through a G-3 glass filter funnel. THF is subsequently evaporated in vacuum using a rotary evaporator starting with 15 Torr and 40°C. Under a blanket of dry nitrogen the viscous mixture is transfered to a round bottom flask (brown glass) equipped with a nitrogen inlet. Total removal of THF is achieved by continued evaporation at 25°C/0.01 mbar for approximately two days. A clear colourless rubbery material is obtained. Titration with HCIO4 in glacial acetic acid confirms that almost total conversion of amino groups is achieved (0,01 mEq/g NH2). Hydroxyl-group titration indicates 1.88 mEq/g. (5.2) Synthesis of carboxy-terminated acryloyl morpholine telomer. Under an inert atmosphere, a 1500 mL five-necked glass reactor equipped with glass propeller stirrer, internal thermometer, intensive cooler is charged with 488 mg (1.8 mmol) a,a'-azo-diisobutyramidin dihydrochloride (, 100 mL degassed deionized water and 27.7 g (0.3 mol) thioglyclic acid. A solution of 127.1 g (0.9 mol) 4-acryloyl morpholine in 300 mL degassed deionized water is added. The mixture is stirred at 60°C for four hours. After cooling to room temperature, the solution is adjusted to pH = 5 by addition of 30% KOH- solution. The mixture is diluted with distilled water to 1000 mL total volume. Salts and low molecular weight residues such as unreacted chain transfer agent are removed by reverse osmosis using a Millipore Proscale system equipped with a Millipore Helicon RO-4 Nanomax 50 membrane operating at a pressure of 10 bar. The retentate is adjusted to pH = 3 by addition of 4n HCI-solution. The product is isolated from the obtained retentate by freeze- drying. Endgroup titration indicates 1.45 mEq/g COOH-groups. Elemental analysis indicates sulfur content 4.32%. (5.3) Coupling of carboxy-terminated hydrophilic telomer of Example (5.2) to multi-hydroxy- functional PDMS of Example (5.1). In a 750 mL five-necked glass reactor equipped with a glass anchor stirrer, intensive cooler, Drierite™-f illed drying tube, and an internal thermometer, 14.3 g bis-gluconamido-functional polydimethylsiloxane product obtained according to (5.1) and 8.0 g carboxy-terminated acryloyl morpholine telomer obtained according to (5.2) are dissolved in 40 mL dry THF. A clear solution is formed. A solution of 2.4 g (11.8 mmol) dicyclohexyl carbodiimid and 145 mg (1.18 mmol) 4-dimethylamino pyridine in 10 mL dry THF is added. Formation of a white precipitate is observed immediately. The mixture is stirred overnight at 60°C. The next morning a few drops of water are added to convert excess carbodiimid and stirring at 60°C is continued for one more hour. After cooling to room temperature, the precipitate is filtered off and the solvent removed. The obtained solid is dissolved in 75 mL ethyl acetate and residual insoluble dicyclohexyl urea is removed by filtration. Endgroup analysis indicates 0.73 mEq/g hydroxyl-groups and 0.02 mEq/g unconverted carboxylic acid groups. (5.4) Reaction of isocyanatoethyl methacrylate (IEM) with hydroxyl-groups of the triblock copolymer obtained according to (5.3). A 100 mL three-necked round bottom flask equipped with a magnetic stir bar, internal thermometer, intensive cooler and a Drierite™-filled drying tube is charged with 5 g product obtained according to (5.3) dissolved in 10 mL chloroform. 375 mg (2.42 mmol) distilled IEM is added, as well as 16 mg dibutyltin dilaurate and 12 mg triphenyl bismut. After stirring overnight at room temperature, infrared spectroscopy indicates complete conversion of the isocyanato-groups (absence of an absorption at 2270 cm "1 ). The solvent is evaporated and the product dried under high vacuum (0.01 mbar). (5.5) Formulation of a photocrosslinkable macromer solution and casting and curing of contact lenses. A centrifugation tube is charged with 4.15 g of product obtained according to (5.4) and 1.04 g n-propanol containing 1.2 weight percent of photoinitiator Darocur 2959. The components are thoroughly mixed until a homogeneous viscous solution is formed. The formulation is centrifuged at 5000 rpm for 10 minutes to remove air bubbles. Portions of the formulation are filled into contact lens molds (PP-molds or quartz glass molds) and cured by UV-irradiation for 30 seconds with a UV intensity of 1.9 mW/cm 2 (Macam-lamp). After mold opening perfectly clear and colorless contact lenses are obtained having a high oxygen permeability and good mechanical properties (E-modulus, elongation at break). Example 6: (6.1) Reaction of δ-gluconolactone with IEM. A 200 ml five-necked reaction flask equipped with reflux condenser,nitrogen inlet tube, stirrer and dropping funnel is charged with 9,97 g (56,1 mmols) of carefully dried dried δ- gluconolactone and 100 ml of dry 1 ,3-dioxane. The suspension formed is purged with dry nitrogen gas, and a solution of 17,4 g (112,2 mmols) of IEM and 20 mg of dibutyltin dilaurate (DBTDL) in 50 ml of dry THF is added from the dropping funnel at a temperature of 10 °C over a period of 60 minutes. The reaction mixture is kept under nitrogen and stirred at 25 °C for 8 hrs. Subsequently the reaction is completed by heating the mixture to 50 °C for another 4 hrs. until no NCO-absorption can be detected in the FTIR spectrum of the reaction mixture. The solvents are then removed by evaporation under reduced pressure. After dissolution of the residue in 500ml of dry 1 ,3-dioxane, filtration through a glas filter funnel, freeze drying and subsequent drying at 0,002 mbar a white powder is obtained which is kept in a refrigerator. The structure of the product is confirmed as the bis-IEM adduct of gluconolactone by NMR as well as by titration of the lactone group. The tris-IEM- and tetrakis-IEM-adducts of gluconolactone are obtained by reacting 3 and with 4 moles of IEM with δ-gluconolactone as described above. For complete conversion 8 or 14 hrs. at 50 °C are needed as confirmed by FTIR of the reaction mixtures. The products obtained in 92 and 76 % yield are white powders The presence of the lactone group and the content of acrylic groups is confirmed by titration and by NMR. (6.2) Preparation of bis- and tris- adducts of glucaro-1 ,3;4,6-dilactone with IEM. According to the method described under (6.1) 3,0 g (17,33 mmols) of glucaro-1 ,3;4,6- dilactone are reacted with a) 2,67 g (17,23 mmols), or b) 5,34 g (34,5 mmols) of IEM and 3 mg of DBTDL in 30 ml of dry THF. Reaction times of a) 18 and b) 42 hrs at 40-50 °C are used to achieve complete conversion of the isocyanate as controlled by FTIR. The structure and composition of white powdery products obtained is confirmed by NMR and titration. (6.3) Monoamino terminated N,N-dimethylacrylamide telomer. A carefully degassed solution of 293,3g (3,0 mols) freshly distilled N.N-dimethyl-acrylamide, 37,2 g (0,327 mols) of cysteamine hydrochloride and 4,08 g of a,a-azodiisobutyramidine dihydrochloride in 600 ml of HPLC-grade water (pH adjusted to 3 using 10N HCl)) is slowly dropped into a 1000 reaction flask kept at 60 °C and purged with nitrogen. In order to keep the exothermic reaction under control the addition of the solution to the reaction flask occurs via a horizontal glas tube 60 cm in length and 1 cm wide which is heated to 60°C. The dropwise addititon takes overall 90 minutes. Subsequently the reaction mixture is stirred under nitrogen at 60°C for 4 hrs. The pH of the mixture is adjusted to 10.5 by addition of 1 molar sodium hydroxide solution and diluted to a total volume of 1200 mL. Salts and low molecular weight residues such as unreacted chain transfer agent are removed by reverse osmosis using a Millipore Proscale system equipped with a Millipore Helicon RO-4 Nanomax 50 membrane operating at a pressure of 15 bar. The product is isolated from the obtained retentate by freeze-drying. A white powdery product with an amine content of 0,734 mVal/g and a sulfur content of 2,15 % are obtained. The M n values found are 1360 Da (H 2 N- titration) or 1490 Da (S-content). (6.4-6.8) Following the procedure outlined under (6.3) analogous N.N-dimethylacrylamide telomers of various molecular weights are prepared. The amounts of reagents used as well as the weight average molecular weights obtained are listed in Table 1 : Table 1 1 ) Calculation via GPC using PEG -standard calibration. 2 ) Calculation from S-content. (6.9) Reaction of a DMA telomer with the bis-IEM adduct of glucaro-1 ,3;4,6-dilactone. 11 10g ( 6,8 mmols) of the monoamino N,N-dimethylacrylamide telomer (6.5) are reacted in THF with 3,29 g (6,8 mmols) of the bis IEM adduct of glucaro-1 ,3;4,6-dilactone prepared under (6.2). The glucaro dilactone terminated N,N-dimethylacrylamide telomer with two polymerizable acrylic substituents at the lactone head group is isolated by freeze drying from dioxane and kept refrigerated after drying under vacuum. GPC in THF shows a monomodal molecular weight distribution and confirms that the white solid product obtained does not contain any low molecular components. Titration of the terminal lactone group results in a value of 0,503 mVal /g (theoretical value 0,511 mVal/g). (6.10) Triblock Copolymer with 4 polymerizable groups. 7,07g (3,56 mmoles) of the glucaramido-lactone terminated and bis lEM-substituted telomer prepared under (6.9) are dissolved in 100 ml of dry THF. To the solution is then slowly dropped a solution of 20g (1 ,78 mmoles) of a bis aminopropyl terminated polydimethyl-siloxane (M ~ 11 000) over a period of 90 minutes. After addition of 20 mg of tetrakis-isopropoxi-titanium the reaction mixture is stirred at room temperature for 48 hrs., until the amine titration of the reaction mixture reaches a value of 0,001 mVal/g. After complete removal of the solvent at 25 - 40 °C and 2 - 0,001 mbar 26,6 g (98 %) a highly viscous material is obtained. Titration of the product confirms the absence of residual NH2 and lactone groups. NMR spectroscopy shows that the 4 methacrylic groups have remained unaffected during the coupling reaction. The triblock copolymer contains 19,5 % w/w of hydrophilic PDMA. Example 7: (7.1) Triblock copolymer from N,N-dimethylacrylamide telomer (H2N-PDMA), bis-aminopropyl terminated poly-dimethylsiloxane and glucaro-1 ,3;4,6-dilactone. In a 100 ml 5-necked reaction flask a mixture of 0,62 g (3,56 mmols) glucaro-dilactone, 10 mg of tetrakis-isopropoxy-titanium and 20 ml dry THF is prepared, carefully degassed and purged with dry nitrogen and cooled to 0 °C. Under constant cooling with ice a solution of 20,0 g (1 ,78 mmols) of a bis- aminopropyl terminated polydimethylsiloxane (M ~ 11 000; 0,178 m Val NH2 /g) in 80 ml of dry THF is slowly added over a time period of 120 minutes. By warming up to room temperature and stirring at 25 °C for 50 hrs. the reaction is brought to completion. From the clear colourless solution formed the solvent is completely removed by evaporation at 25 - 50 °C and 2 - 0,002 mbar. The viscous oil obtained (20,6 g) shows a lactone content of 0,17 mVal /g. 9 g (1 ,509 mmols lactone) of the bis- (glucaramido-lactone) terminated PDMS are dissolved in 50 ml of dry THF. To the carefully degassed solution a solution of 3,77 g ( 1 ,509 mmols NH2) of the monoamino terminated NN-dimethylacrylamide telomer prepared under Example (6.7) in 20 ml of dry THF is added, and the mixture is stirred under dry nitrogen for 72 hrs at 30 °C. After removal of the solvent at 40 °C and 2 - 0,002 mbar 12,7 g of a highly viscous, slightly opalescent colourless product are obtained. Titration of the content in residual amine groups (0,001 mVal/g) confirmed that the coupling of the PDMS and the PDMA segments has come to completion. (7.2-7.3) Further triblock copolymers PDMA-glucarodiamide-PDMS-glucarodiamide-PDMA. Following the procedure outlined under (7.1) two additional triblock copolymers are prepared. The amounts and specifications of the startings materials used and of the final products are summarized in Table2 . Table 2 1 ) from Example (6.7); 2 ) from example (6.8) (7.4-7.9) Triblock copolymers PDMA-glucarodiamide-PDMS-glucarodiamide-PDMA with different grades of IEM substitution and various molecular weights. As outlined in Example (5.4) the following triblock copolymers with IEM substituents are prepared by reaction of the glucarodiamide-linked, amphiphilic triblock copolymers prepared in Examples (7.1), (7.2) and (7.3) by reaction with various amounts of IEM in THF. Dibutyltin dilaurate is used as a catalyst. Specifications of the products thus obtained are summarized in Table 3. Table 3 Example 8: (8.1) Carboxy terminated telomer from methacryloyloxy- polyethyleneglycolmethylether. A 100 ml three-necked round bottom flask is charged with a solution of 50,0 g (100 mmoles) of methacryloyloxy-polyethyleneglycolmethylether (Blemer PME 400, n~9), 400,5 mg (4,35 mmoles) of thioglycolic acid, 64,7 mg (0,2 mmoles) of initiator 2,2 Azo-bis-(N,N- dimethyleneisobutyro-amidine)-dihydro-chloride and 200 ml of water (HPLC quality). To the clear solution formed 2 drops of 0,2 N aqueous HCl solution are added. Dissolved oxygen is removed from the solution by 3 repeat cycles of evacuation at 10 Torr and 5 minutes of nitrogen bubbling through the solution. The mixture is then kept under a nitrogen blanket and heated under stirring to 45 °C for two hrs., followed by 4 hrs. at 40 °C. The clear solution is then purified from low molecular weight components by 24 hrs of dialysis against distilled water using a dialysis tube with a cut-off limit of 1000 Da. The distilled water is renewed 3-times during the 24 hrs period. The clear viscous solution is then lyophilized to obtain a 32,3g (64,1 % yield) of a slightly yellowish powder. Titration of carboxy end groups give 0,07 mVal COOH / g which corresponds to an average molecular weight of 1400 Da. (8.1a) Preparation of the N-hydroxy-succinimide (NHS) ester derivative of a monocarboxy- terminated Polyethyleneglycol-meth-acrylate derived bottle-brush-telomer. 2g of the monocarboxy-terminated PEG-methacrylate telomer of Example (8.1) are dissolved in 20 ml of water (HPLC quality). 87 mg N-(3-dimethylaminopropyl)-N'- ethylcarbodiimide (EDC), dissolved in 1 ml HPLC water, and 60 mg of N- hydroxysuccinimide (NHS), dissolved in 1 ml HPLC water, are added to the solution, and the pH of the mixture is adjusted to 4.5 with 0.1 M HCl. The mixture is then stirred at RT for 15 minutes and filtered through 0.22 μm filter. The solution obtained after filtration is ready for a further chemical reaction. (8.2) Triblock copolymer composed of PEG-methacrylate bottle brush segments and a bis-gluconamidoalkyl terminated central PDMS segment. Following the procedure outlined in Example (5.3) 2 segments (M -1400 Da ) of the monocarboxy terminated PEG-methacrylate bottle brush telomer prepared in Example (8.1) or (8.1a) are coupled to one segment of the bis gluconamidoalkyl terminated polydimethylsiloxane (M ~ 5000 Da) prepared in Example (5.1). The triblock copolymer thus prepared is then reacted with 4 molecules of IEM following the method described in Example (5.4) to synthesize a crosslinkable triblock macromonomer. The product thus obtained has a molecular weight of M ~ 8500 Da and contains 33,1 % w/w of PEG segments. Example 9: (9.1) Preparation of a gluconamido terminated N,N-dimethylacryl-amide telomer A solution of 10 g (3,67 mmols) of the monoamino terminated N,N-dimethylacrylamide telomer ( ~ 1360 Da) prepared under Example (6.3) in 50 ml of dry THF is added to a suspension of 1 ,303 g (7,34 mmols) of gluconolactone in 30 ml of dry THF The reaction mixture is stirred for 48 hrs. until a clear solution is formed. After filtration through a glas filter funnel the solvent is evaporated from the solution at 0,1 - 0,002 mbar. The residue is dissolved in 250 ml distilled water and then freeze dried. After careful drying of the residue at 0,002 mbar a white powdery product is obtained. Titration of the product confirms the absence of unconverted lactone and amine groups. (9.2) Synthesis of polydimethylsiloxane with terminal isocyanate functions. Under an inert atmosphere, a 750 mL five-necked glass reactor equipped with a glass anchor stirrer, interior thermometer, intensive cooler and a dropping funnel is charged with 8.03 g (36 mmol) distilled isophorone diisocyanate, 80 mg dibutyl tin dilaurate, and 100 mL dry THF. The homogeneous solution is cooled to -10°C. Hydroxyalkyl-terminated polydimethylsiloxane (Shin-Etsu KF-6003, OH-titration: 0.36 mEq/g) is degassed and dried under vacuum (0.01 mbar) at 70°C for 30 minutes. After cooling to room temperature, 100 g (36 mmol OH-groups) KF-6003 is filled into the dropping funnel and added dropwise to the diisocyanate solution during 90 minutes, maintaining the solution temperature at -10°C. The solution is stirred at 0°C for another 90 minutes. The solvent is removed on a rotary evaporator at 35°C. Residual solvent is removed under high vacuum (0.002 mbar) and a clear, colorless and viscous liquid is obtained. NCO-titration: 0.31 mEq/g (theory 0.33 mEq/g). Hydroxyl-content below detection limit. (9.3) Triblock copolymer from HO-PDMS-OH, IPDI and gluconamido-propyl terminated PDMA The isocyanato terminated PDMS compound according to (9.2) is dissolved in 30 ml of dry THF and a solution of 7,43 g (7,75 mmoles) of the gluconamido terminated PDMA telomer prepared in Example (9.1) in 50 ml dry THF is added. After stirring for 10 minutes at 25 °C 20 mg of dibutyltin dilaurate are added. The reaction is brought to completion by stirring at room temperature for 12 hrs., until no OCN absorbance can be detected in the FTIR spectrum of the reaction mixture. Then the solvent is completely removed under vacuum at 25 - 40 °C and 2 - 0,01 mbar and a white solid is obtained. (9.4) Synthesis of a reactive macromer by reaction of IEM with the copolymer of (9.3) The triblock copolymer of Example (9.3) is converted to a reactive macromer by reacting it with IEM in the manner as outlined in Example (5.4). ExamplelO: Contact Lenses from amphiphilic triblock copolymers. Following the procedure outlined in Example (5.5) amphiphilic triblock macromonomers are used to prepare contact lenses. Ethanol is used as a solvent for lens casting. Properties of the lenses obtained are determined in the fully hydrated state after autoclaving. Table 4 summarizes data on surface wettability (dynamic contact angles: advancing/ receding/hysteresis). Table 4 : 1 ) Determination with the dynamic Wilhelmy method using a Krϋss K-12 instrument (Krϋss GmbH, Hamburg, Germany). Wetting force on the solid is measured as the solid is immersed in or withdrawn from a liquid of known surface tension. Example 11 : (11.1) Contact lenses from a copolymer network of an amphiphilic PDMA-PDMS-PDMA triblock macromonomer and a PDMS crosslinker. Following the procedure described in Examples (10.1) to (10.5) 1 ,46 g of the triblock macro- monomer prepared in Example (7.7) and 0,625 g of the polysiloxane of formula (15) according to Example 1 are dissolved in ethanol to form a clear solution with a content of 60 % w/w solids. With regard to the mixture of polymerizable components thus formed the overall content in hydrophilic components is ~ 35 % w/w. Contact lenses cast from this formulation show dynamic contact angles (Adv./Rec./Hyst.) 79/46/34 as well as a high oxygen permeability and good mechanical properties. (11.2-11.3) Contact lenses from further PDMA-PDMS-PDMA triblock macromonomers and a PDMS crosslinker. In anlogy to Example (11.1) contact lenses are cast and photo-cured from the triblock macromonomers prepared in Examples (7.6) and (7.9) using the multivinyl PDMS component of Example 3 as a crosslinker. The composition of the fomulations and contact angles of the lenses obtained are summarized in Table 5. Table 5 1 ) Determination see Example 10

Claims: What is claimed is: 1. An amphiphilic block copolymer of formula wherein A is a hydrophobic polysiloxane or perfluoroalkyl polyether segment; B is a surface-modifying hydrophilic segment having a weight average molecular weight of >100 that is devoid of a crosslinkable group; Q is a moiety comprising at least one crosslinkable ethylenically unsaturated group; (alk) is C 2 -C 20 -alkylene which is unsubstituted or substituted by hydroxy; Li, L 2 and L 3 are each independently of the other a linking group; p1 and q1 are each independently of the other an integer from 1 to 12; and either t is 0 and p and q are each independently of the other an integer from 1 to 25; or t is an integer from 1 to 8 and p and q are each 0. 2. An amphiphilic block copolymer according to claim 1 of formula (Q " ^(alk) — L, A— Ur- (alk)" - 1 " Q)p1 (1a), wherein A, B, Li, L 2 , L 3 , Q, (alk), p1 and q1 are each as defined in claim 1. 3. An amphiphilic block copolymer according to claim 1 of formula (B - L 2 ) q A (L. - Q), (1b), wherein A, B, Li, L 2 and Q are each as defined in claim 1 , and p and q are each independently of the other an integer from 2 to 20. 4. An amphiphilic block copolymer according to claim 1 , wherein A is a polysiloxane segment of formula wherein (alk') is alkylene having 1 to 20 carbon atoms which may be interrupted by -O-; x is 0 or 1 ; 80 to 100 % of the radicals R 1 ( Ri', Ri", R 2 , R 2 ', R 2 ", R 3 and R 4 , independently of one another, are Cι-C 8 -alkyl, and 0-20% of the radicals Ri, R Ri", R 2 , R 2 ', R 2 ", R 3 and R 4 , independently of one another, are unsubstituted or C C alkyl- or C C - alkoxy-substituted phenyl, fluoro(Cι-Cι 8 -alkyl) or cyano(Cι-Cι 2 -alkyl), Si is an integer from 5 to 700; s 2 is the sum of (p+q+t-2) if x is 0, and is the sum of (p+q+t) if x is 1 ; wherein p, q and t are as defined in claim 1 , and the sum (Sι+s 2 ) is from 5 to 700. 5. An amphiphilic block copolymer according to claim 1 , wherein Li, L 2 and L 3 are each independently of the other a bivalent linking group of formula - Xi - C(O) -NH - Rio - NH - C(O) - X 2 - (4a), - Xi - C(O) - R 10 - C(O) - X 2 - (4b), - Xι - C(O) - (4c), - C(O) - X 2 - (4d), or wherein Xi and X 2 are each independently of the other a group -O-, -S- or -NR 0 -, Ro is hydrogen or Cι-C -alkyl, and Rio is linear or branched Cι-C 8 -alkylene or unsubstituted or Cι-C -alkyl- or Cι-C 4 -alkoxy-substituted C 6 -Cι 0 -arylene, C 7 -Cι 8 -aralkylene, C 6 -C 10 -arylene- Cι-C 2 -alkylene-C 6 -Cιo-arylene, C 3 -C 8 -cycloalkylene, C 3 -C 8 -cycloalkylene-d-C 6 -alkylene, C 3 -C 8 -cycloalkylene-Cι-C 2 -alkylene-C 3 -C 8 -cycloalkylene or Cι-C 6 -alkylene-C 3 -C 8 - cycloalkylene-Cι-C 6 -alkylene. 6. An amphiphilic block copolymer according to claim 5, wherein Li is a linking group of formula (4a), (4c) or (4e), L 2 is a linking group of formula (4a), and L 3 is a linking group of formula (4c). 7. An amphiphilic block copolymer according to claim 1 , wherein B is a non-ionic segment selected from the group consisting of a polyoxyalkylene, polysaccharid, polypeptide, poly(vinylpyrrolidone), polyalkylacrylate or -methacrylate, polyhydroxyalkylacrylate or -methacrylate, polyacyl alkylene imine, polyacryl amide, polyvinyl alcohol, polyvinyl ether and a polyol, or is a polyionic segment selected from the group consisting of a polyallylammonium. polyethyleneimine, polyvinylbenzyltrimethylammonium, polyaniline, sulfonated polyaniline, polypyrrole and polypyridinium segment, and a poiyacrylic and polymethacrylic acid, a polythiophene-acetic acid, a polystyrenesulfonic acid and a zwitterionic segment, or a suitable salt thereof. 8. An amphiphilic block copolymer according to claim 1 , wherein B is a telomer segment of formula wherein (Alk") is C 2 -Cι 2 -alkylene, T is a monovalent group that is suitable to act as a polymerization chain-reaction terminator, m and n are each independently of another an integer from 0 to 250, wherein the total of (m+n) is an integer from 2 to 250, R 20 and R 20 ' are each independently of the other hydrogen or Cι-C 4 -alkyl; R 2 ι is a hydrophilic non-ionic, anionic, cationic or zwitterionic substituent; and R 2 ι' independently has the meaning of R 2 ι. 9. An amphiphilic block copolymer according to claim 8, wherein R 2i and R 21 ' are each independently of the other a radical -COO-Cι-C 2 -alkyl, -COO-(CH 2 ) 2 . -OH, -CONH 2 , -CON(CH 3 ) 2 , -CONH-(CH 2 ) 2 -OH, -COO(CH 2 ) M -NHC(O)-O-G wherein -O-G is the radical of trehalose 10. An amphiphilic block copolymer according to claim 1 , wherein Q is a radical Qi of formula wherein (Alk) is linear or branched Cι-Cι 2 -alkylene, X is -O- or -NH-, Rn is an olefinically unsaturated copolymerisable radical having from 2 to 24 carbon atoms which is unsubstituted or further substituted by Cι-C alkoxy, halogen, phenyl or carboxy, and w is the number 0 or 1. 11. An amphiphilic block copolymer according to claim 1 , wherein Q is a polyoxyalkylene, poly(vinyipyrrolidone), poly(hydroxyethylacrylate), poly(hydroxyethylmethacrylate), polyacrylamide, poly(N,N-dimethylacrylamide), poiyacrylic acid, polymethacrylic acid, polyacyl alkylene imine, a hydrophilic telomer or a copolymeric mixture of two or more of the above-mentioned polymers which in each case comprises one or more ethylenically unsaturated bond and has a weight average molecular weight of, for example, >100. 12. An amphiphilic block copolymer according to claim 11 , wherein Q is a hydrophilic segment of formula -((alk")-O) c -[(CH 2 -CH 2 -O) a -(CHR 6 -CHR 7 -O) b ]-(alk")-Lι'-Q 2 (5a) wherein L ' is a bivalent linking group of formula - X, - C(O) -NH - R.o - NH - C(O) - X 2 (4a), - Xi - C(O) - R 10 - C(O) - X 2 - (4b), - C(O) - X 2 - (4d), or - X 1 - C(O) - X 2 - (4e), wherein Xi and X 2 are each independently of the other a group -O-, -S- or -NR 0 -, Ro is hydrogen or C C 4 -alkyl, and Rio is linear or branched Cι-Cι 8 -alkylene or unsubstituted or d-C 4 -alkyl- or d-C -alkoxy-substituted C 6 -Cι 0 -arylene, C 7 -Cι 8 -aralkylene, C 6 -Cι 0 -arylene- Cι-C 2 -alkylene-C 6 -Cι 0 -apylene, C 3 -C 8 -cycloalkylene, C 3 -C 8 -cycloalkylene-Cι-C 6 -alkylene, C 3 -C 8 -cycloalkylene-Cι-C 2 -alkylene-C 3 -C 8 -cycloalkylene or Cι-C 6 -alkylene-C 3 -C 8 - cycloalkylene-CrC 6 -alkylene, Q 2 is a radical of formula wherein (Alk) is linear or branched Cι-Cι 2 -alkylene, X is -O- or -NH-, Rn is an olefinically unsaturated copolymerisable radical having from 2 to 24 carbon atoms which is unsubstituted or further substituted by Cι-C 4 alkoxy, halogen, phenyl or carboxy, and w is the number 0 or 1 , Q 3 is C 3 -Cι 2 -alkenyl or a radical -(CH 2 )ι. 4 -O-Rι 6 wherein Rι 6 is acryloyl, methacryloyl or a group -C(O)-NH-(CH 2 ) 2 ^,-O-C(O)-C(Rι 7 )=CH 2 and Rι 7 is hydrogen or methyl, Q is a radical of formula 'R 18 9, Xi 9 CH 2 (9c), or H, CH, -C C=CH, (9d), H, CH, wherein X 3 is -O- or -NR, R is hydrogen or C r C 4 -alkyl, X 4 is a group -C(O)-O-, -O-C(O)-NH- or -NH-C(O)-O-, (Alk') is Cι-C 8 -alkylene, e is an integer of 0 or 1 , and Rι 8 is Cι-Cι 2 -alkylene, phenylene or C 7 -Cι 2 -phenylenealkylene, one of the radicals R 6 and R 7 is hydrogen and the other is methyl, (alk") is Cι-C 6 -alkylene, c is the number 0 or 1 , and each of a and b independently of the other is a number from 0 to 100, the sum of (a+b) being from 2 to 100, R 8 is hydrogen; Cι-Cι 2 -alkyl unsubstituted or substituted by hydroxy or fluoro and/or uninterrupted or interrupted by oxygen; C 5 -C 8 -cycloalkyl; phenyl; or benzyl, R 9 is d-Cι 2 -alkyl, benzyl, C 2 -C 4 -alkanoyl, benzoyl or phenyl, (Alk") is C 2 -C 12 -alkylene, T is a monovalent group that is suitable to act as a polymerization chain-reaction terminator, m and n are each independently of another an integer from 0 to 250, wherein the total of (m+n) is an integer from 2 to 250, n1 is an integer from 1 to 4, R 20 . R 20 ' and R 20 " are each independently of the other hydrogen or Cι-C 4 -alkyl; R 2 ι and R 2 ι' are each independently of the other a hydrophilic non-ionic, anionic, cationic or zwitterionic substituent; X 5 is -O-, -NH- or -N(d-C 4 -alkyl)- and z is an integer from 2 to 150. 13. An amphiphilic block copolymer according to claim 2 of formula (1a), wherein A is a polysiloxane segment of formula wherein x and s 2 are each 0, and Ri, R Ri", R 2 , R 2 ', R 2 ", R 3 and R 4 are each independently of one another Cι-C -alkyl, B is a polyoxyalkylene, poly(vinylpyrrolidone), poly(hydroxyethylacrylate), poly(hydroxyethylmethacrylate), polyacrylamide, poly(N,N- dimethylacrylamide), poiyacrylic acid, polymethacrylic acid, polyacyl alkylene imine, hydrophilic telomer or a copolymeric mixture of two or more of the above-mentioned polymers, Li is a linking group of formula L 2 is a linking group of the formula - Xi - C(O) -NH - R 10 - NH - C(O) - X 2 - (4a), and L 3 is a linking group of the above formula (4c), wherein Xi and X 2 are each independently of the other a group -O-, -S- or -NR 0 -, R 0 is hydrogen or Cι-C -alkyl, and Rι 0 is linear or branched Cι-Cι 8 -alkylene or unsubstituted or Cι-C 4 -alkyl- or Cι-C 4 -alkoxy-substituted C 6 -Cι 0 -arylene, C 7 -C 18 -aralkylene, C 6 -Cι 0 -arylene- C C 2 -alkylene-C 6 -Cιo-arylene, C 3 -C 8 -cycloalkylene, C 3 -C 8 -cycloalkylene-d-C 6 -alkylene, C 3 -C 8 -cycloalkylene-Cι-C 2 -alkylene-C 3 -C 8 -cycloalkylene or d-C 6 -alkylene-C 3 -C 8 - cycloalkylene-Cι-C 6 -alkylene, Q is a radical Qi of formula wherein (Alk) is linear or branched Cι-Cι 2 -alkylene, X is -O- or -NH-, Rn is an olefinically unsaturated copolymerisable radical having from 2 to 24 carbon atoms which is unsubstituted or further substituted by C -C 4 alkoxy, halogen, phenyl or carboxy, and w is the number 0 or 1 , or Q is a polyoxyalkylene, poly(vinylpyrrolidone), poly(hydroxyethyl- acrylate), poly(hydroxyethylmethacrylate), polyacrylamide, poly(N,N-dimethylacrylamide), poiyacrylic acid, polymethacrylic acid, polyacyl alkylene imine, hydrophilic telomer or a copolymeric mixture of two or more of the above-mentioned polymers which in each case comprises one or more ethylenically unsaturated bond and has a weight average molecular weight of, for example, >100, and p1 is an integer from 1 to 6, and q1 is an integer from 1 to 8. 14. An amphiphilic block copolymer according to claim 3 of formula (1b), wherein A, B, Li, L 2 and Q are as defined in claim 13, and p and q are each independently of the other an integer 2 to 15. 15. A process for the manufacture of a molding, which comprises crosslinking an amphiphilic block copolymer of formula (1 ) according to claim 1 in a mold. 16. A process according to claim 15 wherein the molding is an ophthalmic molding and wherein the block copolymer is photo-crosslinked in an ophthalmic mold using actinic radiation. 17. A molding obtainable by a process according to claim 15. 18. A molding according to claim 17, which is an ophthalmic molding, in particular a contact lens, intraocular lens or an artificial cornea.

Inventors: HIRT THOMAS, HOLLAND TROY VERNON, LOHMANN DIETER, SCHREMMER JACALYN MARY, HIRT, THOMAS, HOLLAND, TROY, VERNON, LOHMANN, DIETER, SCHREMMER, JACALYN, MARY
Applicants: HIRT THOMAS, HOLLAND TROY VERNON, LOHMANN DIETER, NOVARTIS AG, NOVARTIS ERFIND VERWALT GMBH, SCHREMMER JACALYN MARY, HIRT, THOMAS, HOLLAND, TROY, VERNON, LOHMANN, DIETER, NOVARTIS-ERFINDUNGEN VERWALTUNGSGESELLSCHAFT M.B., SCHREMMER, JACALYN, MARY
Application year: 2000
Main classification: C08F290
IPC codes: A61L27, C08G18, C08G77, C08G81, G02B1