Production of ophthalmic devices based on photo-induced step growth polymerization

A method for producing hydrogel contact lenses, comprising the steps of:

• (1) obtaining a fluid composition, wherein the composition comprises at least one first prepolymer having multiple first propagating groups and a step-growth-propagating agent having two or more second propagating groups, wherein the first propagating groups are ene-containing groups which are mono-valent or divalent radicals each containing a carbon-carbon double bond which is not direactly linked to a carbonyl group (—CO—), a benzene ring, a nitrogen atom, or an oxygen atom, wherein the second propagating groups are thiol groups each co-reactive with one of the first propagating group in a photo-induced step-growth polymerization to form a hydrogel material;
• (2) introducing the fluid composition into a cavity formed by a mold, wherein the mold has a first mold half with a first molding surface defining the anterior surface of a contact lens and a second mold half with a second molding surface defining the posterior surface of the contact lens, wherein said first and second mold halves are configured to receive each other such that a cavity is formed between said first and second molding surfaces;
• and
• (3) photo-inducing step-growth polymerization of the composition in the mold to crosslink said at least one first prepolymer in the presence of the step-growth propagating agent to form the hydrogel contact lens,
• wherein said the first propagating groups are ene-containing groups of formula (I), (II), or (III)
• in which R1 is hydrogen, or C1-C10 alkyl;
• R2 and R3 independent of each other are hydrogen, C1-C10 alkene divalent radical, C1-C10 alkyl, or —(R18)a—(X1)b—R19 in which R18 is C1-C10 alkene divalent radical, X1 is an ether linkage (—O—), a urethane linkage (—N), a urea linkage, an ester linkage, an amid linkage, or carbonyl, R19 is hydrogen, a single bond, amino group, carboxylic group, hydroxyl group, carbonyl group, C1-C12 aminoalkyl group, C1-C18 alkylaminoalkyl group, C1-C18 carboxyalkyl group, C1-C18 hydroxyalkyl group, C1-C18 alkylalkoxy group, C1-C12 aminoalkoxy group, C1-C18 alkylaminoalkoxy group, C1-C18 carboxyalkoxy group, or C1-C18 hydroxyalkoxy group, a and b independent of each other is zero or 1, provided that only one of R2 and R3 is a divalent radical;
• R4-R9, independent of each other, are hydrogen, C1-C10 alkene divalent radical, C1-C10 alkyl, or —(R18)a—(X1)b—R19, optionally R4 and R9 are linked through an alkene divalent radical to form a cyclic ring, provided that at least one of R4-R9 are divalent radicals;
• n and m independent of each other are integer number from 0 to 9, provided that the sum of n and m is an integer number from 2 to 9;
• R10-R17, independent of each other, are hydrogen, C1-C10 alkene divalent radical, C1-C10 alkyl, or —(R18)a—(X1)b—R19, p is an integer number from 1 to 3, provided that only one or two of R10-R17 are divalent radicals,
• wherein said at least one first prepolymer is obtained from a copolymer with pendant or terminal functional groups by covalently attaching the ene-containing groups to the pendant or terminal functional groups of the copolymer, wherein the first prepolymer is capable of forming a hydrogel material, and
• wherein the copolymer with the pendant or terminal functional groups comprises siloxane units.