Patent ID: 6376572
Filing Date: 2002-04-23
Classification: C08F,C08G,C08L,C09D

Abstract:
Composition for preparing by radical polymerization polymeric films having a refractive index lower than 1.400, said composition comprising:a) a perfluoropolyether of the following formula: Tâ€²â€”RfTâ€ƒâ€ƒ(Ia) â€ƒwherein: T and Tâ€², equal to or different from each other, are selected from the group consisting of: â€”CF2â€”CH2â€”Oâ€”COâ€”CR&boxH;CH2, â€ƒand â€”CF2â€”CH2â€”Oâ€”COâ€”RIâ€”CR&boxH;CH2 â€ƒwherein: R=H, CH3; RI=â€”NHâ€”CH2â€”CH2â€”Oâ€”COâ€” or NHâ€”RIIâ€”NHCOOâ€”CH2â€”CH2â€”OCOâ€”RII being an aliphatic C3-C10, C5-C14 cycloaliphatic or alkylcycloaliphatic, C6-C14 aromatic or alkylaromatic radical; Rf is a fluoropolyether having an number average molecular weight from 400 to 5,000, and is selected from those having one or more of the following units statistically distributed along the chain: (C3F6O), (CFYO) wherein Y is F or CF3, (C2F4O), (CR4R5CF2CF2O) wherein R4 and R5 are equal to or different from each other and are H or Cl, and one fluorine atom of the perfluoromethylene unit can be substituted with H, Cl, or perfluoroalkyl having from 1 to 4 carbon atoms; b) from 0.1 to 10% by weight, of a perfluoropolyether having the following formula: â€ƒTâ€”Rfâ€”CH2OHâ€ƒâ€ƒ(Ib)wherein T and Rf are as above defined; c) from 0 to 30% by weight of compounds selected from the group consisting of: (c1) compounds not containing fluorine: c1a) mono-, bi-, polyfunctional non fluorinated (meth)acrylic esters, obtained by reaction of (meth)acrylic acid with the following hydroxylated compounds: aliphatic oligoethers having the hydroxyl group at one or both the terminations, formed by (CtH2tO)nx units wherein t is 2 or 3 and nx ranges from 2 to 5; mono-, polyhydroxylated aliphatic alcohols, with a number of hydroxyl functions from 1 to 4, linear or branched, with a number of carbon atoms between 2 and 18; cyclo- or polycycloalipathic alcohols having with a number of carbon atoms for each ring between 3 and 6, wherein the ring can optionally be substituted with one or more alkyl groups C1-C3; or c1b) vinyl monomers, copolymerizable with the (meth)acrylic esters c1a); â€ƒand c2) compounds containing fluorine, selected from the group consisting of: c2a) mono (meth)acrylate perfluoropolyethers having the formula: YACF2ORfâ€³CFXpCH2(OCH2CH2)pOCOCR&boxH;CH2â€ƒâ€ƒ(Ic2a) â€ƒwherein YA=F, Cl, CF3, C2F5, C3F7, C4F9; and Xp=F, CF3; R as above defined wherein p is zero or an integer from 1 to 5; Rfâ€³to represents a radical having a perfluoropolyether structure with an number average molecular weight in the range 400-3,000, said radical formed of sequences of alkylene oxyfluoro structures, chosen from the following units: â€”CF2Oâ€”, â€”CF2CF2Oâ€”, â€”CF2CF2CF2Oâ€”, â€”CF2(CF3)â€”CFOâ€”, â€”(CF3)CFOâ€”, â€”CF2CF2CH2Oâ€”, â€ƒand c2b) perfluoroalkyl mono(meth)acrylates of formula: (RfI)pIQOCOCH&boxH;CH2â€ƒâ€ƒ(Ic2b) â€ƒwherein RfI is a fluoroalkyl radical having C3-C30, or a perfofluoropolyether radical (PFPE) containing in the chain the units mentioned in c2a) and having a number of carbon atoms from 5 to 30; pI is 1 or 2; Q is an aliphatic C1-C12 or aromatic C6-C12 divalent linking bridge; Q optionally contains heteroatoms N, O, S, or carbonylimino, sulphonylimino or carbonyl groups; Q is unsubstituted or is linked to substituents selected from halogen atoms, hydroxyl groups, or alkyl radicals C1-C6; d) from 0.1 to 10% by weight of photoinitiator and/or radical initiators, the amount of component a) being the complement to 100% of the composition, with the proviso that defining B0 as the mole number of the â€”CF2CH2OH terminals and B1 as the sum of the moles of the (meth)acrylic end groups, obtained by the sum of T+Tâ€² of the components a) and b), the (B0+B1)/B1 ratio is in the range 1.50-1.01.