Patent GB-856318-A (GB)
Title: Improvements in and relating to polyurethane compositions
IPC: C08K5/00
Filed: 1959-01-13
Abstract: A polyurethane composition, having greater resistance to photo-degradation caused by ultraviolet light than the constituent polyurethane, comprises at least one polyurethane, at least one 2, 21-dihydroxybenzophenone which has the property of absorbing strongly all wave-lengths of ultraviolet light between 3,500 and 4,000   and at least one promoter of the following formulae: <FORM:0856318/IV(a)/1> wherein R is a hydrogen atom or a lower alkyl radical (i.e. 1 to 8 carbons) and Y is a lower alkyl radical or a phenyl radical:  <FORM:0856318/IV(a)/2> wherein E is a lower alkyl radical, G is a -S-radical or an alkylene radical <FORM:0856318/IV(a)/3> and R1 is a hydrogen atom or an alkyl radical containing not more than 2 carbon atoms:  <FORM:0856318/IV(a)/4> wherein J is a lower alkyl radical, a phenyl radical or a lower alkyl-substituted phenyl radical:  <FORM:0856318/IV(a)/5> wherein L is a phenyl radical, or lower alkyl substituted phenyl radical or a-C(E)3 radical E being as defined above:  <FORM:0856318/IV(a)/6> wherein X is a benzyl radical or a -CR2R3R4 group wherein R2, R3 and R4 are each hydrogen or a lower alkyl group or R2, and R3 may be alkylene radicals joined to form a 5- or 6-membered ring; T is a phenyl radical or an alkyl radical containing not more than two carbon atoms and M is a benzyl radical or <FORM:0856318/IV(a)/7> wherein R5 and R6 are each a hydrogen or a lower alkyl radical with the proviso that R3, R4 and R5 cannot all be hydrogen in the same compound:  <FORM:0856318/IV(a)/8> where R is as defined above: <FORM:0856318/IV(a)/9> <FORM:0856318/IV(a)/100> wherein Q is a hydrogen atom or a <FORM:0856318/IV(a)/111> radical; the total amount of the 2,21-dihydroxybenzophenone constituent and of the promoter constituent being 0,1 to 3% and 0,1 to 2% of the weight of polyurethane constituent.  The compositions may take the form of films or fibres.  The dihydroxybenzophenones preferably have the structure <FORM:0856318/IV(a)/122> <FORM:0856318/IV(a)/133> wherein Z and Z1 are each hydrogen or lower alkyl and Z11 is a lower alkyl radical.  The compositions can be prepared by reaction of a polyol with excess polyisocyanate, addition of the promoter and dihydroxybenzophenone to the product, and chain extension with water, an aliphatic polyol, an arylene diamine or hydrazine.  Alternatively the promoter and dihydroxybenzophenone can be incorporated into the already chain extender polyurethane by milling in or in solution; in for example, xylene, toluene, methyl ethyl ketone and ethyl acetate. As organic polyols for the preparation of the polyurethane there may be used polyesters (straight or branched, including lactone polyesters), polyalkylene-ether glycols, polyalkyleneether-thioether glycols, and polyalkylene-aryleneether glycols.  Specified promoters are 2, 21-methylene-bis (6-tert-butyl), 4-methyl or 4-ethyl or 4-phenyl-phenol), 2, 21-methylene-bis[-methyl-6 (1, 1, 3, 3-tetramethylbutyl) phenol], 4, 41-butylidene-bis (6-tert butyl-m-cresol); 4, 41-bis (6-tert-butyl-m-cresol) sulphide; 2, 21-methylene-bis (2, 4-dimethyl-phenol); 2-tert-butyl-4-(4-tert-butyl phenol); 2-tertbutyl-4-phenylphenol; 2, 6-dibenzyl-4- methylphenol; 2-benzyl-4-methylphenol; 2-benzyl-6-tert-butyl-4-methylphenol; 2, 6-dibenzyl-4-methyl-phenol; 2-benzyl-4-methylphenol; 2-benzyl-6-tert-butyl-4 methylphenol; 2-benzyl-6-tert-butyl-4-ethylphenol; 2, 4-dimethyl-6-(1-methyl-1-cyclohexyl) phenol; 2, 6-diisopropyl-4-methylphenol; 2, 4-bis (1,1-dimethylpropyl)-phenol; 2, 4-dimethyl-6-isopropyl phenol; 2, 4-dimethyl-6-tert-butyl phenol; 2, 5-di-tert-butyl hydroquinone; phenothiazine; N, N1-di(b -naphthyl)-p-phenylenediamine and N-phenyl-b -naphthyl-amine. Specified chain-extenders include 4, 41-methylene bis (2-chloro-, or 2-methyl or 2-methoxy aniline), mesitylene diamine, 1, 5, naphthalenediamine, m-phenylene diamine, 1, 4-butanediol, 1, 5-pentanediol, ethylene glycol, 1, 2, 6-hexanetriol, trimethylolethane or propane, or ethylene oxide-modified trimethylol propane or pentacrythritol. 2, 21-dihydroxy-4, 41-dimethoxybenzophenone or, 2, 2,4,41-tetra-hydroxybenzophenone are employed in examples, polyurethanes have incorporated varions of the specified promoters.  In control experiments one or other of the promoter or benzophenone compound is omitted and the results are given.