Method for the Production of Polyvinyl Acetals
Polyvinyl acetals with a high degree of acetalization and low solution viscosity are prepared by acetalizing partly or fully hydrolyzed polyvinyl ester polymers dissolved or slurried in aldehyde.
1 .- 12 . (canceled)
13 . A process for the preparation of polyvinyl acetals, comprising acetalizing partly hydrolysed or fully hydrolysed vinyl ester polymers with at least one aldehyde having 1 to 15 carbon atoms, wherein the vinyl esters comprise unbranched or branched C 1-15 alkylcarboxylic acids and the vinyl ester polymers have ≧50 mol % of vinyl alcohol units, wherein the partly hydrolysed or fully hydrolysed vinyl ester polymers are dissolved or slurried in the aldehyde used for acetalizing.
14 . The process of claim 13 , wherein the vinyl ester polymers contain polymerized vinyl esters selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, vinyl pivalate and vinyl esters of a-branched monocarboxylic acids having 5 to 11 carbon atoms.
15 . The process of claim 13 , wherein at least one aldehyde is selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde.
16 . The process of claim 14 , wherein at least one aldehyde is selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde.
17 . The process of claim 13 , wherein the degree of hydrolysis of the partly hydrolysed or fully hydrolysed vinyl ester polymers is ≧50 mol %.
18 . The process of claim 17 , wherein the degree of hydrolysis of partly hydrolysed polyvinyl esters is 70 to 90 mol % and the degree of hydrolysis of fully hydrolysed polyvinyl esters is ≧96 mol %.
19 . The process of claim 13 , wherein acetalizing is carried out until products having an OH number of 4 to 12 are obtained.
20 . The process of claim 13 , further comprising forming a film of said polyvinyl acetal and employing said film as a film in safety glass or as an acoustic film.
21 . The process of claim 15 , further comprising formulating said polyvinyl acetal as a binder in a printing ink, primer or corrosion protectant.
22 . The process of claim 13 , further comprising adding said polyvinyl metal to a ceramic composition as a binder.
23 . The process of claim 13 , further comprising adding to said polyvinyl acetal at least one powder selected from ceramic powders and metal powders.
24 . The process of claim 13 , further comprising applying said polyvinyl acetal to the inside of a can with a crosslinker, and crosslinking to form an interior coating on the can.
25 . The process of claim 13 , further comprising adding said polyvinyl acetal to glass fibers as a binder.