Abstract:
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.
Abstract:
Pulverulent ethylene-vinyl alcohol copolymers may be produced in highly pure form, in particular containing no surfactant residues, by hydrolyzing an ethylene-vinylester copolymer in alcoholic solution and precipitating the copolymer in particulate form employing a cooling temperature gradient, optionally with addition of water.
Abstract:
Silane-containing polymers are prepared by the polymerization of one or more ethylenically unsaturated monomers in the presence of a silane-containing aldehyde, hemiacetal, or acetal as a regulator, optionally with further regulators as well. The silane-containing regulators produce polymers with superior properties and with improved polymerization parameters as compared to the conventional mercaptosilane regulators.
Abstract:
Organosilicone and vinyl ester copolymers free from phase separation are prepared by copolymerizing at least one vinyl ester monomer with organosilicones containing difunctional silicone monomers and optionally a minor amount of monofunctional silicone monomers, in a non-aqueous solvent mixture containing at least one solvent with a transfer coefficient greater than 20·10−4 relative to vinyl acetate.
Abstract:
Low molecular weight polyvinyl acetals have a solution viscosity of from 2 to 12 mPas and a degree of polymerization Pw less than 200, and are obtained by hydrolyzing a vinyl ester polymer having a solution viscosity of from 1.0 to 1.6 mPas until the content of vinyl alcohol units is ≧50 mol %, to produce a polyvinyl alcohol whose solution viscosity is from 1.0 to 2.0 mPas, and then acetalizing the resultant polyvinyl alcohol. The products may be used as binders and films of increased adhesion to substrates.
Abstract:
Semiconductor wafers are glued onto a carrier foil which is stretched across a frame. Instead of restretching the carrier foil directly at a processing machine, the foil is restretched on an adapter frame which can be stored and then later manipulated in the processing machine. The adapter frame includes a clamping ring, a base ring, and a threaded ring which secures the carrier foil.
Abstract:
Polyvinyl acetals which contain acetal moieties derived by acetalizing polyvinyl alcohol with both aliphatic aldehydes or their derivatives and with amino- and/or ammonium-substituted aldehydes display exceptional substrate adhesion when used in printing ink as binders, allowing inks without adhesion promoters to be produced.
Abstract:
The invention relates to a method for producing thin layers (3) of a silicon that can be subjected to plastic treatment, whereby the silicon layer (3) is extruded, and to the thin silicon layer produced by said method.
Abstract:
Polyvinyl acetals are obtained in a cost-effective and environmentally advantageous manner by employing as at least a portion of the aqueous acetalization medium, the mother liquor from a previous acetalization reaction.
Abstract:
Low shear-thinning polyvinyl acetals having a solution viscosity in 30 % strength by weight solution in methyl ethyl ketone which changes by not more than 10% in a shear rate range from 1 to 100 s−1. The preparation of the low shear-thinning polyvinyl acetals involves acetalation of partly hydrolyzed or completely hydrolyzed vinyl ester polymers comprising ≧50 mol % of vinyl alcohol units with one or more aldehydes, optionally in the form of the hydrates, hemiacetals or full acetals, wherein from 0 to 60% by weight of the aldehyde, based on the total amount of the aldehyde, is initially introduced over the course of the first one to ten minutes of the acetalation and is prereacted over the course of from 1 to 30 minutes, and the remaining proportion is then metered in continuously over the course of at least 20 minutes.