| 摘要 |
<p>1. A copolymer which consists essentially of polymerized units of a) from 67 to 98% by weight of one or more esters of acrylic acid or methacrylic acid with a straight-chain or branched monoalkanol of 1 to 14 carbon atoms, b) from 2 to 20% by weight of one or more copolymerizable olefinically unsaturated compounds containing 3 to 10 carbon atoms and one or more carboxyl or carboxylic acid anhydride groups, c) from 0 to 31% by weight of a vinyl-aromatic, and d) from 0 to 5% by weight of other alpha,beta-ethylenically unsaturated compounds, not mentioned under a) to c), with the proviso that the sum of their percentages mentioned under a) to d) is 100, which copolymer has K value, according to DIN 53,726, of from 18 to 60 and contains components a), b), c) and d) as polymerized units in such a ratio that the copolymer has an A value of from 180 to 220, which value can be calculated according to the following equation see diagramm : EP0043911,P10,F2 where SZ is the acid number in mg of KOH/g of copolymer and see diagramm : EP0043911,P10,F4 is the sum of the corrected contents E1 -En , each in percent by weight based on the copolymer, of COO groups in the particular alkyl (meth)acrylate comonomers a)1-a)n, these contents in percent by weight being corrected by multiplying them by a factor of 0.7 for esters of alpha-branched alkanols and by a factor of 0.8 for esters of beta-branched alkanols.</p> |
