FLUORINATED POLYESTERS

Abstract: New polyesters comprising polyoxyfluoroalkylene blocks are prepared by polycondensation of diols with dicarboxylic acids or with derivatives thereof, said fluorinated polyesters being characterized by such improved surface properties that any subsequent treatments of the surface of the articles obtained therefrom are needless.

Description: Fluorinated Polyesters BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to fluorinated polyesters of the thβr ■oplaβtic or theraoelaatoseric type. 2. The Prior Art There are known thermoplastic polyesters, which are widely utilized as files, fibres, supports for magnetic tapes, structural materials in fields such as the electronic or the biomedical. They are gene= rally prepared by polycondensation of aromatic diacidβ or their dβ_ riratiTeβ with diols. Typical examples are polyethyleneterephthala ^ te and polybutyleneterephthalate, which are obtained by sation of terephthalic acid or of a derivative thereof, for example a diester, with ethylene glycol or butaadiol, respectively. There are also known thermoβlaβtomeric polyesters obtained by cons densatioa of a diacid or a derivative thereof, such as e.g. a dieβter, with a low molecular weight glycol and with a polyglycol, generally a polyoxyalkylene glycol having a molecular weight from 1000 to 3000. The thermoplastic and thermoelastoneric polyesters are character! , zed by high mechanical and electrical characteristics, a good βtabi= lity to solvents and to hydrolysis. For a plurality of uses such as films, supports for magnetic tapes, fibres, in various sectors of goods, they exhibit however consider rable drawbacks, as they have a low oil.and water-repellency, a low resistance to soiling and low free flowing properties, character!= zed by a high friction coefficient, so that a subsequent finishing treatment of such articles is absolutely necessary. In particular, as regards the use for magnetic recording tapes, where the material flows on metal or plastic surfaces, a surface treatment of said surface with a lubricant iβ required in order to reduce friction and to secure the eliding of the tape and preβerve it as much as possible from the wearing. For theβe uses, very thin o layers on the substrate surface, generally from 50 to 1,000 A, -are sufficient. For other uses, for example in particular in the biomedical field, the conventional hydrogenated polyesters, although exhibitin -in comparison with other utilizable materials - improved impermeabili, ty and mechanical properties, do not exhibit good bioeoapatibility and antithrombogenicity. With a view to overcoming these drawbacks, the hydrogenated poly= esters are therefore subjected to finishing processes or surface treatments. Theβe finiβhing processes or these surface treatments are gene= rally carried out, for example, with a fluorinated oil or with a solution or a dispersion of a fluorinated plastic polymer, such as, for example, a polytetrafluoroethylene dispersion, depending on the type of application. However, theβe fluorinated coatings exhibit the drawback of not sufficiently adhering to the subβtra te, owing to the surface properties which are typical of the flu£ rinated polymer and which interfere with the adhesion. By conβ£ quence, since it is not possible to maintain the fluorinated layer adherent to the article for a sufficiently long period of time, a degradation of the surface properties occurs, such as resistance to chemical agents, oil- and water-repellency, resistance to βoi= ling, free flowing which, conversely, are indispensable for a plu= rality of uses. An alternative method of increasing the duration of the aboveβaid surface properties consists in chemically binding a fluorinated monomer to the polymeric substrate by grafting. Thiβ proceββ can be carried out, for example, by uβing radiation or electric diβ= charge. With such method, however, the obtainmeat of a uniform layer iβ strictly related to the substrate nature. In fact, on substrates having an irregular shape no uniform layer of fluorinated coating can be obtained. According to another method of obtaining fluorinated coatings on non-fluorinated polyesters, a non-fluorinated polyester iβ coex= truded with a fluorinated copolymer, for example a ethylene/hexafluoropropene polymer. This method, however, besides requiring a particularly complex technology, can be rarely used, as it can be applied only for particular types of articles, for example fibres. By consequence, there was the requirement of having available rea. dily proceβsable polyesters which permit to overcome the abovβs said problems of finishing or of surface treatment, and at the βa me time having the above-cited characteristics of chemical inertia, mechanical properties, oil- and water-repelleney, biocompatibility. THE PBESENT INVENTION It haβ now surprisingly been found that polyesters compriβing fluoropolyoxyalkylene units represent a novel technological so= lution which permits to overcome the above-cited limitations as they permit to avoid all surface treatments or finishing opera= tions. Thus, the object of the present invention iβ a polyester charac terized by a block βtructure and comprising, with reβpect to the total number of moles constituting the polyester, amounts not hi gher than k5% by moles of at least one fluoropolyoxyalkylene com priβing the repeating fluoropolyoxyalkylene units selected from the following classes: I (C^O), (CF 2 0), said unite being randomly distributed along the fluoropolyoxyalkylene chain; II (C 3 6 0), (C^O), (CFXO) where X = -F or -C J βaid units being randomly distributed along the perfluoropolyoxyalkylene chain; III -CH 2 -CF 2 -CF 2 -0- said units being linked to one another inside the fluoropoly= oxyalkylene chain as shown by the following structural formu= la: -(0-CF2_-CF2_-CH2-)'p-0-B « f--0-(CH2,-CF2_-CF2.-0)'q- where R'f_ is a fluoroalkylene group, preferably containing 1 to 8 carbon atoms, p and q are integers, +q is at least 2 and, preferably, up to 200; βaid unite being linked to one another inside the fluoropoly= oxyalkylene chain as shown by the following structural formu= 8 carbon atoms, x is 0 or 1, a and b are integers and a+b is at least 2 and, preferably, up to 30; V (CF 2 CF " 2 0) ' ; VI (CF 2 CF 2 CF 2 0). The fluorinated polyesters of the invention are prepared by directly carrying out a polycondensation of fluoropolyoxyalkyl= ones compriβing the aboveβaid repeating unite with the cited diolβ or carboxylic diacidβ or derivatives thereof. Such fluoropolyoxyalkyle 1 ->* having functional groups at both ends contain hydroxy end groups or carboxylic end groups and have an average molecular weight of from about ^00 to 10,000, the minimum value depending on the type of repeating structure, so that polyesters having a molecular weight equal to at least 20,000 are obtained. The polymers so obtained, besides retaining the excellent pro= perties of the polyesters, particularly mechanical and electri , cal properties, . chemical inertia to common solvents, exhibit also improved surface characteristics, such aβ oil- and water- -repellency, low friction coefficient, chemical inertia to ag= greβsive agents βuch aβ hydrocarbon fluids or chlorinated sol= vents, so avoiding the difficulties connected with the prepa= ration and the carrying out of the fluorinated βurface treatment needed for the conventional polyesters. These materials are therefore particularly suitable for a wide variety of uses such aβ e.g. oil- and water-repellent filmβ and fibres, βubβtrates for magnetic tapes, biocompatible structural materials for bio= medical uses. For the preparation of the polyesters of the invention the fol= lowing compounds are utilized: 1) a hydrogenated diacid or dieβter or diacylchloride having the following general formula: wherein T and ϊ' , equal or different one another, are ha= logon or Ofi« , wherein R* iβ H or an alkyl radical contai= ning from 1 to 8 carbon atomβ or an aryl radical having from 6 to 10 carbon atoms; fi 2 iβ a divalent radical having from 2 to 30 carbon atoms such aβ, for example: a) an alkylene radical of the type: CH, CH, ~ ~ -(CH 2 ) B , - - CCHH - - OOHH - ¬ (CH 2 ) a , wherein m* is an integer from 2 to 20; b) a fluorinated or non-fluorinated arylene radical such as for example para- or aeta-phenylene, para- or meta-xylene; c) a cycloaliphatic or polycyclic, fluorinated or non-fluori. nated, divalent radical, such as for example 1, -cyclohe-β xylene, 1 ,3-cyclohexylene, 2«methyl-l, i f-eyclohexylβne, 2-mβthyl- ,3-cyclohexylene, diarylenmethane, etc. Particularly suitable for the purposes of the invention are the aromatic diearboxylic acids, such aβ for example the tereph= thalic, phthalic and iβophthalic acids and their derivatives; 2) a hydrogenated diol containing an alkylene radical having from 2 to ' ** ■ carbon atoms, such as ethylene, propylene, tetramethyl ene, hexamethylene, dodecamethylene, cyclohexylene, 2,2-dimβ= thyltrimethylene or cyclohexanrdimethylene; 3) a difunctional derivative having an average molecular weight from about ^00 to 10,000, preferably from 500 to 5,000, com= prising the fluoropolyoxyalkylene units described above in classes I, II, III, IV, V and VI and having end groups of the following type: - (CH 2 ) y -(0CH 2 CH 2 ) a -A wherein v and z are integers or zero, preferably v is 0 or 1, and z is 0 or an integer up to 3; A is OH, in βu-:h case v being at least 1, or COT, T being the same as defined before. Difunctional derivativeβ having end groupβ aβ described before and belonging to class I are particularly βelected from those comprised in the following general formula..: A - (CH 2 CH 2 0) z - (CH 2 τ - CF 2 0 - (C^O)^ - (CF.,0) n - -CF 2 -(CH 2 ) v -(0CH 2 CH 2 ) a -A wherein v, z and A have the meaning defined hereinbefore and m and n are positive integers such that the molecular weight falls within the indicated range. One can prepare theβe fluoropolyoxyalkylene derivativeβ according to known methods, aβ described for example in patents US 3,810,87^ and US 3,8^7,978. Difunctional derivativeβ having the above described end groupβ and belonging to class II are particularly selected from those comprised in following general formula: A-CH 2 -CF 2 -(C 3 F 6 0) (C^O) fl (CFX0) t -CF 2 -CH 2 -A wherein X is -F or -CF,, indexes r, s, t are positive gers such that the molecular weight is as above indicated, and A is as defined hereinbefore. One can prepare such compounds by photo-oxidation of C,Fg and C^ mixtures, as described in US patent 3,665,0 1, and by successively converting -C0F end groups into groupβ containing the end group A, βuch conversion being accompli ^ shed according to known methods as described for example in patentβ US 3,8^7,978 and US 3,810,87 . Difunctional derivativeβ having the above described end groupβ and belonging to class III are particularly selected from the compounds having general formula: A-C 2 CH 2 (0C 2 CF 2 CH 2 ) -CR» f 0-(CH 2 C 2 CF 2 0) CH 2 C 2 -A wherein p, q, A and H' are the same aβ defined hereinabove. Theβe compounds are described in published European patent application 148,482, and the end groups containing -COF can be converted so as to have end groups A, as is described in patents US 3,84?,978 and US 3,810,874. Difunctional derivativeβ having the above cited end groups and belonging to class IV are particularly selected from the compounds having general formula: where a, b, A, R., x have the meaning defined hereinbefore, n is a positive integer. Such compounds are described in published European patent application 151,877 and the end groups containing -COF are converted in order to have end groups A aβ is described in patents US 3,847,978 and US 3,810,874. Difunctional derivatives having end groups as described be= fore and belonging to classes V and VI, are prepared by the processes described respectively in US patent 4,523,039 and European patent application 148,482, both succeββively fol= lowed by the treatments described in Italian patent applica_ tion 22920 A/85; 4) a hydrogenated polyoxyalkylene glycol having an average mo= lecular weight from about 400 to 4,000 and preferably from 1,000 to 2,000, having the following general formula: H0(C d H 2d 0) g H where d = 1-4 and g = 6-70, C d H 2d being linear or having side-chains. Representative examples of such rlaββ of compounds are: polyethylene glycol, polypropylene glycol, polytetraaethyl ^ ene glycol. The fluorinated polyester of the present invention are prepared by properly mixing the above-specified compounds in such way that at least one of them iβ a fluoropolyoxyalkylene derivative and the molecular weight of the final polyester is not lower than 20,000. According to the present invention, the fluorinated polyesters comprising the fluoropolyoxyalkylene derivative in amounts not exceeding ~% by moles, preferably from 0.1 to # by moles with respect to the total number of moles constituting the polyester are particularly suitable for substrates for magnetic tapes, oil- and water-repellent films and fibres. The polyesters of the invention having a content of fluoropoly= oxyalkylene units higher than % by moles are particularly utili= zable in the biomedical field due to their high biocompatibility. By properly varying the components from 1) to 4), it is possible to obtain thermoplastic or thersoelaβtomeric materials. The thermoelaβtomeric materials contain a rubber-like phase which may consist either of fluoropolyoxyalkylene or of polyoxyalkylene glycol or of mixtures thereof. Generally, in the presence of high fluoropolyoxyalkylene contents, for example of by moles, the polyester iβ thermoelaβtomeric; in caβe of lower amounts, ^ 5% by moleβ, it iβ neceββary to add polyoxyalkylene glycol β . One can prepare the polyesters of the invention by conventional polycondensation techniques, such as for example, in bulk, in solution, in emulsion, interface polycondensation. Always according to the known polyester synthesis methods, the polycondensation can be carried out starting from diearboxylic acids and diols, or by transeβterification βtarting from dieβterβ and diols, or from diacylchlorideβ and diols. Particularly βuitable for the purposes of the present invention is the transeβterification and bulk-polycondensation proceββ βtarting from mixtures of dieβterβ and diols. Such process is accomplished by first heating the mixture of rea= gents dieβterβ and diols, in proper molar ratios, in the presence of a catalyst, to a temperature from about 200 to 24θ*C; in this step, the distillation of the by-products (alcohols) generated during the transeβterification takes place. The reaction is carried out in an inert atmosphere, under vigorous stirring and for a time sufficient for the complete removal of the by-products. The operation time depends on the monomer type, the temperature, the catalyst and the excess of diol employed. This process step leads to a low molecular weight prepolyner which is converted to a polymer having a molecular weight suitable for high temperature (250-300*C) polycondensation under βtirring and at a reβidual pressure lower than 1 torr, in order to remove the excess of low molecular weight diol. The polycondensation time, which is a function of the operative conditions, generally ranges from 0.3 to 10 hours. It iβ possible to use different types of catalysts, such as, for example, βaltβ of divalent and trivalent metals, such as calcium, manganese, iron, magnesium, aluminium, zinc; oxides of germanium, lead and antimony; alkaline metals (sodium, potassium) alkoxideβ, titanium alkoxides (isopropylate, butylate). Both process steps, i.e. transeβterification and polycondensation, are generally effected in the absence of solvents: the materials are in the molten state. The polycondensation can be also carried out in solution, using diacylchlorides and diols. The fluorinated polyeβterβ of the preβent invention, aβ mentioned above, permit to obtain, by βuitably varying the βtarting compo= sition of the mixture, both plastic-type and elaβtomeric-type ma= terialβ, each type being characterized by excellent mechanical properties. Those skilled in the art will have no difficulty in determining the best compositions for the various utilizations. The mechanical properties of theβe fluorinated polyesters, however, can be modified, according to the requirements and the desired ap= pliances, by adding various inorganic additives known in the art, such as carbon black, silica gel, alumina and glass fibres. For a few uses, in particular, it is advisable to incorporate stabili= zers to heat and to ultraviolet radiations, well known in the art. Furthermore, it is possible to obtain polyeβterβ with a different fluorine content by properly varying the initial molar ratio of the fluoropolyoxyalkylene derivative to the other reagents. The fluorinated polyesters obtained according to the present in= vention have the same fields of use as the analogous non-fluorina= ted polyesters with the advantage that the articles prepared from said fluorinated polyesters, for example, by injection molding or compression molding processes, exhibit, aβ compared with the known products, improved properties as regardβ oil- and water-repellency, self-lubrication, free flowing and biocompatibility. This properties improvement occurs also for very low amounts, even of . ~ % by moles, of fluoropolyoxyalkylene compound with respect to the final polyester. A further advantage of the polyesters of the preβent invention iβ the possibility of mixing a thermoplastic or thermoelastomeric po= l ester having a high fluorine content, according to the invention, with other fluorinated or non-fluorinated polymeric materials, and of treating the resulting mixture according to a βuitable convert βion technology. In this way it is possible to have available a wide range of materialβ endowed with improved properties in compa= rison with those obtained from the individual components of the mixtures. The polyesters of the invention were characterized by- determining: Melting point: thermal differential analysis at a heating rate of 20»C/ainute. Technological properties: modulus tenβile βtrβngth -, ASTM D 638 and D 412 elongation at break Shore hardness -ASTM D 2240 contact angle: determination by means of a 40 X grazing light microscope friction coefficient ASTM D 189^-73 water absorption ASTM D 570 - 24 hours. The test-pieces were prepared by compression molding, operating at temperatures higher by 30-4θ β C than the polymer melting point, the polymer having been previously dried at 100°C under vacuum. The following examples are given for merely illustrative purpo= βes and are not to be considered aβ limitative of the invention. EXAMPLE 1 120.6 g (0.62 mols) of dimethyl terephthalatβ (DMT), 89.4 g (0.99 mols) of 1,4-butandiol and 1.2 1θ" 5 mols of titanium tetraisopropylate (in an iβopropanol solution) were charged into a tree-neck flask having a 0.5-liter volume, equipped with a stirrer, a dropping funnel and a column for the diβtillation of the reaction by-prodvcts. Into the dropping funnel there were introduced 62 g (0.031 mols) of o t CJU-bis-hydroxy-polyoxyper luoroalkylene having an average molecular weight equal to 2000 (formula deβcribed at point 3), belonging to class I with A = OH; V = 1; Z = 1). The flask was repeatedly subjected to vacuum and nitrogen-fil_ ling cycles and was subsequently dipped into an oil bath pre= viously heated to 200*C. The reaction was conducted under stirring and in a nitrogen atmosphere, and the methanol distillation begun directly after melting of the mass. After 30 minutes, when the distillation of the theoretical amount of methanol was concluded, the polyoxyper luoroalkylene diol waβ added and the whole was allowed to react for 1 hour at 210 β C. The bath temperature waβ then brought to 250°C while the sure was gradually lowered to 0.1 torr. Polycondensation waβ carried out for 2 hours, where-after it was cooled to room temperature while simultaneously introducing nitrogen into the reaction flask until the atmospheric pressure was reached. The fluorinated polyester, having the appearance of a light maaβ, exhibited the following characteristics: melting point: 22θ e C Fluorine content: 8 by weight Shore hardness D: 72 tensile strength: 54θ kg/cm elongation at break: 310%. The oil- and water-repellency properties and the friction coeffi= cient of the fluorinated polyester were compared with those of a polybutyleneterephthalate sample (check A). Fluorinated Check A polyester contact angle with H.,0 104 55 Q contact angle with ligroin 20 complete wetting contact angle with nitromethane 55 36 dynamic friction coefficient («) 5 on steel 0.15 0.33 H 2 0 absorption (% by weight) 0.08 0.65 EXAMPLE 2 Using the apparatus and the modalities described in example 1, a fluorinated thermoelastomeric polyester waβ prepared, which con= sisted of a rigid crystalline phase, a rubber-like amorphous hy= 5 drogenated phase, an amorphous fluorinated phase having a very low Tg. The reacting mass consisted of DMT (48.5 g, equal to 0.25 mols), 1,4-butandiol (36 g, equal to 0.4 mole), polyoxytetramethylene 0 glycol having an average molecular weight equal to 1000 (100 g equal to 0.1 mole) and Irganox IO98 IR) (1 g) as antioxidant. In the second step there waβ added fluoroalkylene having an average molecular weight equal to 2000 and having the formula deβcribed at point 3), belonging to class 5 I with A = OH; v = 1; Z * 1 (12.5 g corresponding to O.OO625 moles). The catalyst is titanium tβtraiβopropylate (0.1% by moles referred to DMT ). After a 2-hourβ polycondensation, a high molecular weight fluorina= ted copolyester was obtained, which exhibited the following propers ties: melting point: 1 4 β C Fluorine content: 4.6% by weight Shore hardness D: 52 tensile yield strength (25% modulus) : 13 kg/cm tensile βtrength: 490 kg cm elongation at break: 48θ%. Analogously with the preceding example, the fluorinated polymer properties were compared with those of a thermoelaβtomeric copoly= ether-eβter not containing fluorine (check B). Fluorinated Check B thermoelastomeric polyester ______ contact angle with H 2 0 110 62 contact angle with ligroin 15 complete wetting contact angle with nitromethane 59 39 dynamic friction coefficient (M) on steel 0.20 0.45 EXAMPLE 3 776 g (* mols) of dimethylterephthalatβ, 744 g (12 mole) of ethylene glycol, 0.7 g of manganese acetate (II) and 0.7 g of antimony oxide (III) were charged into a glaβs reactor ha= ving a 3 1 volume, equipped with a stirrer, a dropping funnel and a column for the distillation of the reaction by-products. Into the dropping funnel there were introduced 80 g (0.04 mols) of c , JJ -biβ-(methylcarboxylate)-polyoxyperfluoroalkylene ha= ving an average molecular weight equal to 2000 (formula deecr_ bed at point 3) belonging to class I, with A = COOCH , v = z = = 0). The reactor was repeatedly subjected to vacuum cycles and was βubβequently dipped into an oil bath heated to l8θ β C. The mixture waβ stirred for 2 hours, during which the distilla= tion of methanol took place; after this period of time, the fluorinated diester was added and the whole was allowed to further react for 1 hour. The bath temperature was then brought to 28θ°C, while siaultane= ouβly and progresβively reducing the prββsurβ to 0.1 mm Hg. After a 2-hour polycondensation, during which the distillation of the ethylene glycol in excess occurred, it was cooled to room temperature. The fluorinated polyester (m.p. = 25θ°C, Fluorine content = 5% by weight), after grinding in a rotary ball mill, was extruded at 290°C by means of a laboratory flat-head extruder, was cooled to 25 β C, longitudinally stretched at 95 # C to 300%, transversally stretched at 120 β C to 300% and βubβequently treated at 215 β C for a few seconds to give a biaxially oriented film having a thick= ness of 100 /urn. The fluorinated polyeβter film exhibited improved surface proper= ties with respect to a conventional polyethyleneterephthalate film. In fact, the values of the contact angle with H 2 0 and of the dy= namic friction coefficient on steel were equal to 103° and to 0.25, respectively, in comparison with 70° and O.55 of a poly= ethyleneterephthalate film not containing fluorine.

Claims: , . 10 CLAIMS: 1. A polyββter having a block βtructure and comprising , with re= βpect to the total number of moles constituting the polyester, not more than 45 mole % of at least one -fluoropo¬ lyoxyalkylene compriβing the repeating fluoropolyoxyalkylene units selected from the following classes: I (CJF^O), (CF 2 0) , βaid unite being randomly diβtributed along the fluoropolyoxyalkylene chain; II CjF 6 0), (C 2 F 0), (CFXO) with X = -F or -CF j , βaid unite being randomly diβtributed along the fluoropolyoxyalkylene chain; III -CH 2 -CF 2 -CF 2 -0- said units being linked to one another inside the fluoropo= lyoxyalkylene chain as shown by the following structural formula: -(0-CF2--CF2--CH2.)p-0-R»f-0-(CH2.CF2-.CF2,-0)q- where R 1 . is a fluoroalkylene group, p and q are integers, p+q iβ at least 2; said units being linked to one another inside the fluoro= polyoxyalkylene chain as shown by the following structural are integers and a+b is at least 2; (CF 2 CF 2 0) VI CF 2 CF 2 CF 2 0 . The polyester according to claim 1 prepared by using the follo= wing compounds: 1) a hydrogenated diacid or diester or diacylchloride having the following general formula: wherein T and Y», equal or different one another, are halo= gen or OR' , wherein R' is H, or an alkyl radical containing from 1 to 8 carbon atoms, or an aryl radical having from 6 0 to 10 carbon atoms; R 2 is a divalent radical having from 2 to 30 carbon atoms, selected from: a) an alkylene radical; b) a fluorinated or non-fluorinated arylene radical; -5 c) a cycloaliphatic or polycyclic, fluorinated or non-flu£ rinated divalent radical t' 2) a hydrogenated diol containing an alkylene radical having from 2 to 1 carbon atoms; 0 3) a difunctional derivative having an average molecular weight from about 4oo to 10,000, comprising the fluoropolyoxyalkyl ene units of classes I, II, III, IV, V and VI of claim 1), and having end groups of the following type: 5 - (CH 2 ) τ -(0CH 2 CH 2 ) a -A wherein v and z are integers or zero, A iβ OH, in such case v being at least 1, or COT, T being as defined hereinbefore at point 1); 0 ) a hydrogenated polyoxyalkylene glycol having an average molecular weight from about 400 to 4,000, having the fol= lowing general formula: H0(C d H 2d 0) g H where d = 1-4 and g = 6-70, C d H 2d being linear or having 5 side chains. 3* The polyester according to claim 2, wherein the alkylene ra= dical of point a) is selected from: ? H 3 -<CH 2 al - - CH,) c -(CH,). I CH, !H, CH, I 3 I 3 and -<CH 2 Bf - CH - CH - CH^, - , wherein m* is an integer from 2 to 20. 4. The polyester according to claim 2, wherein the arylene ra= dical of point b) is selected from para-phenylene, meta-phe= nylene, para-xylene and meta-xylene. 5 * The polyester according to claim 2, wherein the divalent ra= dical of point c) is selected from 1,4-cyclohexylβne, 1»3- -cyclohexylene, 2-methyl-1,4-cyclohexylβnβ, 2-methyl-1,3- -cyclohexylene and diarylenmethane. 6. The polyester according to claim 2, wherein the compound 3) has an average molecular weight from 500 to 5*000. 7 * The polyester according to claim 2, wherein the compound 4) has an average molecular weight from 1,000 to 2,000. 8. The polyester according to claim 2, wherein v iβ zero or 1 and z is zero or an integer from 1 to 3. 9. The polyester according to claim 2, wherein the compound 1) iβ an aromatic diearboxylic acid. 10. The polyester according to claim 2, wherein the compound 3) has the following general formula: A - (CH 2 CH 2 0) z - (CH 2 ) v - CF 2 0 - (C^O^ - (CF_0) a - -CF.-(CH-) -(0CH-CH.) -A 2 2 y 2 2 z wherein v, z and A have the sam<* meaning as defined in claim 2 and m and n are positive integers such that the molecular weight falls within the range indicated in claim 2 at point 3 ) 11. The polyester according to claim 2, wherein the compound 3) has the following general formula: A-CH 2 -CF 2 _(C 3 F 6 0) r (C 2 F | 0) s (CFX0) t -CF 2 CH 2 -A where X is -F or —CF, the indexes r, s, t are positive inte= gers such that the molecular weight is that indicated in claim 2, point 3), and A is the same as defined in claim 2. 12. The polyester according to claim 2, wherein the compound 3) has the following general formula: A-CF 2 CH 2 (0CF 2 CF 2 CH 2 ) -0R» 0-(CH 2 CF 2 CF 2 0) OH 2 -CF 2 -A where p, q and R' are as defined under class III) of claim 1 and A is the same as defined in claim 2. 13. The polyester according to claim 2, wherein the compound 3) has the following general formula: where 1, n is a positive integer and A is the same as defined in claim 2. 14. The polyester according to claim 1, wherein the amount of the fluoropolyoxyalkylene compound ranges from 0.1 to 5% by mole with reβpect to the final polyester. 15. Use of the polyester of claim 1 in the biomedical field.

Inventors: CAPORICCIO GERARDO, DE GIORGI MARCO, RE ALBERTO, CAPORICCIO, GERARDO, DE GIORGI, MARCO, RE, ALBERTO
Applicants: AUSIMONT SPA, AUSIMONT S.P.A.
Application year: 1986
Main classification: C08G63
IPC codes: A61L27, A61L33, C08G63