Moisture curable balloon materials
View Patent ↗The present invention relates to a catheter device having a dilatation balloon formed from a polymeric material crosslinked by moisture through —Si—O—Si— linkages, and to a method of making the same. The polymeric material is formed by reacting at least one organofunctional hydrolyzable silane with at least one polymer. The crosslinked polymeric structure is ideal for forming more resilient and durable catheter balloons. In particular, the catheter balloons have excellent abrasion resistance.
1. A method of forming a catheter balloon comprising the steps of:
a) providing at least one polymeric material at or above its melt temperature;
b) providing at least one organofunctional hydrolyzable silane compound;
c) extruding a) and b) into a tubular preform at a temperature wherein a) and b) react;
d) forming said tubular preform into a balloon preform;
e) blowing said balloon preform into a balloon; and
f) exposing said balloon or balloon preform to water;
wherein said a) and b) react to form a polymeric material having hydrolyzable groups on said silane wherein said hydrolyzable groups crosslink upon exposure to water and form —Si—O—Si— linkages.
2. The method of claim 1 wherein said at least one organofunctional hydrolyzable silane has the following general structure:
where X is a monovalent non-hydrolyzable organic moiety comprising at least one functional group W which is reactive with said polymeric material with the proviso that an Si—C bond is present between Si and W; Y is a hydrolyzable group, Z is a monovalent hydrocarbon group, and m is an integer from 1 to 3.
3. The method of claim 1 wherein said at least one hydrolyzable silane has the following general structure:
where R′ is a hydrogen atom or lower C 1 to C 4 alkyl; x and y are 0 or 1 with the proviso that when x is 1, y is 1; n is an integer from 1 to 12 inclusive, preferably 1 to 4, and each R independently is a hydrolyzable organic group such as an alkoxy group having from 1 to 12 carbon atoms, aryloxy group, araloxy group, aliphatic acyloxy group having from 1 to 12 carbon atoms, amino or substituted amino groups, or a lower alkyl group having 1 to 6 carbon atoms inclusive, with the proviso that not more than one of the three R groups is an alkyl.
4. The method of claim 3 wherein said hydrolyzable silane is selected from vinyltrimethoxysilane, vinyltriethoxysilane, allytrimethoxysilane, and γ-(meth)acryloxypropyltrimethoxysilane.
5. The method of claim 2 wherein W is selected from (meth)acrylamido, (meth)acryloxy, carboxyl, epoxy, amino, ureido, isocyanato, thiocyanato, mercapto, styryl, vinyl, allyl, haloalkyl, acid anhydride, sulfonyl azide, carboxylic acid esters of aromatic alcohols, and mixtures thereof.
6. The method of claim 2 wherein X is selected from epoxycyclohexyl, glycidoxypropyl, isocyanatopropyl, vinyl, and allyl.
7. The method of claim 2 wherein Y is alkoxy of C 1 to C 4 .
8. The method of claim 2 wherein said hydrolyzable silane is selected form isocyanatopropyltriethoxysilane, glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.
9. The method of claim 1 wherein said polymeric material is amino functional.
10. The method of claim 1 wherein said exposure to water is accomplished in a water bath.
11. The method of claim 1 wherein in during said blowing step, said balloon is further axially stretched.