Patent EP-2336254-A1 (EP)
Title: Polymer dispersions
Inventor: HARTIG JENS
IPC: C09J133/06
Filed: 2009-12-18
Abstract: Coating composition comprises at least one polymer dispersion obtainable by at least two-stage emulsion polymerization comprising: a first stage, which includes reaction of e.g. (a1) at least one alkyl (meth)acrylate, (b1) optionally at least one vinyl aromatic, (c1) at least one hydroxyalkyl (meth)acrylate with an alkyl group, (d1) optionally at least one radically polymerizable compound including ethylenically unsaturated nitriles, vinyl esters of carboxylic acids, vinyl halides, and vinyl ethers of alcohols; and second stage which includes a radical polymerization. Coating composition comprises at least one polymer dispersion obtainable by at least two-stage emulsion polymerization comprising: a first stage, which includes reaction of (a1) at least one alkyl (meth)acrylate, (b1) optionally at least one vinyl aromatic having up to 20 carbon atoms, (c1) at least one hydroxyalkyl (meth)acrylate with an alkyl group comprising 1-10 carbon atoms, (d1) optionally at least one radically polymerizable compound including ethylenically unsaturated nitriles having up to 20 carbon atoms, vinyl esters of carboxylic acids containing up to 20 carbon atoms, vinyl halides having up to 10 carbon atoms, and vinyl ethers of alcohols having 1-10 carbon atoms, (e1) optionally at least one alpha ,beta -ethylenically unsaturated carboxylic acid, (f1) optionally at least one cross-linker, (g1) optionally at least one compound including 2-(2-oxoimidazolidine-1-yl) ethyl meth(acrylate) (ureidoethyl (meth)acrylate), acetoacetoxyethyl acrylate, acetoacetoxypropyl methacrylate, acetoacetoxybutyl methacrylate, 2-(acetoacetoxy)ethyl methacrylate, diacetone acrylamide (DAAM), and diacetone methacrylamide, (h1) optionally at least one compound having a (meth)acrylate group and an epoxy group, and (i1) optionally at least one alpha ,beta -ethylenically unsaturated carboxamide, in the presence of at least one initiator and optionally in the presence of at least one emulsifier and also, optionally in the presence of at least one regulator. The copolymer obtained from the first stage exhibits an acid number of not > 10 mg potassium hydroxide/g polymer according to DIN EN ISO 3682(potentiometric), a hydroxyl number of 2-100 mg potassium hydroxide/g polymer according to DIN 53240-2(potentiometrically at a acetylation of 20 minutes), a particle size of 20-80, preferably 30-60 nm, and a weight-average molecular weight of 5000-50000 g/mol, which is determined by a size exclusion chromatography with tetrahydrofuran containing 0.1 wt.% of trifluoroacetic acid as an eluent at a flow rate of 1 ml/minute and column temperature of 35[deg] C, and the sum of the monomers (c1) and (i1) is from 0.5-20 wt.%; and second stage in the presence of the copolymer prepared in the first stage, which includes a radical polymerization of (a2) at least one alkyl (meth)acrylate, (b2) optionally at least one vinyl aromatic having up to 20 carbon atoms, (c2) optionally at least one hydroxyalkyl (meth)acrylate with an alkyl group comprising 1-10 carbon atoms, (d2) optionally at least one radically polymerizable compound including ethylenically unsaturated nitriles having up to 20 carbon atoms, vinyl esters of carboxylic acids containing up to 20 carbon atoms, vinyl halides having up to 10 carbon atoms, and vinyl ethers of alcohols containing 1-10 carbon atoms, (e2) optionally at least one alpha ,beta -ethylenically unsaturated carboxylic acid, (f2) optionally at least one cross-linker, and (g2) optionally at least one compound including 2-(2-oxoimidazolidine-1-yl)ethyl meth(acrylate) (ureidoethyl (meth)acrylate), acetoacetoxyethyl acrylate, acetoacetoxypropyl methacrylate, acetoacetoxybutyl methacrylate, 2-(acetoacetoxy)ethyl methacrylate, DAAM, and diacetone methacrylamide, (h2) optionally at least one compound having a (meth)acrylate group and an epoxy group, and (i2) optionally at least one alpha ,beta -ethylenically unsaturated carboxamide, optionally followed by at least one further stage of a radical polymerization of at least one monomer. The amount of the optional at least one emulsifier is 0.1-3.5 wt.%, based on the total amount of the radically polymerizable monomers metered into the radical polymerization in all the stages, where the weight ratio of the sum of the monomers of the first stage (a1) to (i1) to the sum of the monomers of the subsequent stages (a2) to (i2) is 5:95-70:30, the particle size of product obtained from the last stage is 50-500 nm, the acid number of the product of the last stage is not more than the acid number of the product of the first stage, and the hydroxyl number of the product of the last stage is not more than the hydroxyl number of the product of the first stage.