Fluorine-containing hydrogel-forming polymeric materials

Claim 1

A contact lens consisting essentially of a copolymer and at least 63% by weight water wherein the copolymer is a crosslinked fluorine-containing polymeric material suitable for use in biomedical applications, containing units derived either by simultaneous copolymerisation and crosslinking or by copolymerisation and subsequent crosslinking of the following monomers: (1) to 40 mole % of an amide of acrylic or methacrylic acid; (2) 25 to 55 mole % of an N-vinyl lactam of the N-vinyl pyrrolidone type; (3) 5 to 20 mole % of a hydroxyalkyl ester of acrylic or methacrylic acid; (4) 1 to 10 mole % of acrylic or methacrylic acid; and (5) at least about 5 up to about 10 mole % of a hydrophobic monomer component comprising two monomer types a) and b) as follows: (a) a fluorine-containing olefine, or fluorine-containing unsaturated alcohol, carboxylic acid or ester or a non-fluorine-containing unsaturated alcohol which, after copolymerisation of monomer (1) to (5), is esterified using a fluorine-containing aliphatic carboxylic acid or derivative thereof; and (b) a non-fluorine-containing polymerisable hydrophobic vinyl monomer which is at least one monomer selected from vinyl aromatic hydrocarbons of the styrene type and hydrophobic esters of acrylic or methacrylic acid; the monomers (1) to (5) totalling 100 mole %, the crosslinking having been effected with crosslinking amounts of a crosslinking agent, which, in the case of simultaneous copolymerisation and crosslinking, is an ester of a diol and acrylic or methacrylic acid or is divinylbenzene, or, in the case of crosslinking subsequent to copolymerisation, is a latent crosslinking agent which is a diamide of an unsaturated aliphatic carboxylic acid, an anhydride of an aliphatic or aromatic carboxylic acid, a diepoxide or dicumyl peroxide, the crosslinking agent having been used in an amount of up to 5 weight % based on the total weight of monomers (1) to (5).