Polyvinyl alcohols and polyvinyl acetals containing silane
View Patent ↗The invention relates to polyvinyl alcohols and polyvinyl acetals which contain silane and can be obtained by means of a) radical polymerization of at least one vinyl ester of unbranched or branched alkyl carboxylic acids comprising between 1 and 18 C atoms, in the presence of aldehydes containing silane or the hemiacetals or full acetals thereof, b) saponification of the vinyl ester polymers obtained thereby, and optionally c) acetalation of the partially saponified or fully saponified vinyl ester polymers.
1. A process for preparing silane-containing polyvinyl alcohols and polyvinyl acetals by:
a) free-radically polymerizing one or more vinyl esters of unbranched or branched alkylcarboxylic acids having from 1 to 18 carbon atoms in the presence of silane-containing aldehydes or hemiacetals or full acetals thereof to produce a vinyl ester polymer,
b) hydrolyzing the vinyl ester polymers to form a partly hydrolyzed or fully hydrolyzed vinyl ester polymer, and
c) optionally acetalizing of the partly hydrolyzed or fully hydrolyzed vinyl ester polymer.
2. The process of claim 1 , wherein free-radically polymerizing is carried out by means of bulk polymerization, suspension polymerization or by polymerization in organic solvents.
3. The process of claim 1 , wherein hydrolyzing of the vinyl ester polymers takes place in alkaline or acidic media.
4. The process of claim 1 , wherein acetalizing is effected by reacting the partly or fully hydrolyzed vinyl ester polymer with aliphatic or aromatic aldehydes having from 1 to 15 carbon atoms optionally substituted by one or more substituents selected from the group consisting of hydroxyl, carboxyl, sulfonate, ammonium, and aldehyde radicals.
5. The process of claim 1 , wherein further silane-containing compounds or aldehyde-containing compounds or mixtures thereof are additionally used as regulators in the polymerization.
6. The process of claim 1 , wherein the silane-containing aldehydes and hemiacetals and full acetals thereof are selected from the group consisting of compounds of the structural formulae
I) R 3 Si—[OSiR 2 ] y —(CH 2 ) x —CH═O,
II) R 3 Si—[OSiR 2 ] y —(CH 2 ) x —CH(OR 1 ) 2 ,
III) R 3 Si—[OSiR 2 ] y —(CH 2 ) z —Ar—(CH 2 ) z —CH═O,
IV) R 3 Si—[OSiR 2 ] y —(CH 2 ) z —Ar—(CH 2 ) z —CH(OR 1 ) 2 ,
V) O═CH—(CH 2 ) x —Si(R) 2 —O—Si(R) 2 —(CH 2 ) x —CH═O,
VI) [SiO(R)—(CH 2 ) z —CH═O] 3-4 ,
where R individually is halogen; is an unbranched or branched, saturated or unsaturated, optionally substituted alkyl or alkoxy radical having from 1 to 12 carbon atoms; is an acyl radical having from 2 to 12 carbon atoms, where R may optionally be interrupted by one or more non-adjacent heteroatoms selected from the group consisting of N, O, S; is an optionally substituted aryl or aryloxy radical having 3 to 20 carbon atoms, where the aryl radical may also contain one or more heteroatoms selected from the group consisting of N, O, S, and
R 1 individually is H, an unbranched or branched, saturated or unsaturated, optionally substituted alkyl radical having from 1 to 12 carbon atoms which may optionally be interrupted by non-adjacent heteroatoms selected from the group consisting of N, O, S; Ar is an aromatic group which may optionally contain one or more heteroatoms selected from the group consisting of N, O, S, and
x is from 2 to 40, y is from 0 to 100, and z is from 0 to 20.
7. The process of claim 1 , wherein the silane-containing aldehydes are used in an amount of from 0.0001 to 5.0% by weight, based on the total weight of the monomers.
8. The process of claim 1 , wherein ethylenically unsaturated, silane-containing monomers are copolymerized.