| 摘要 |
In the free radical polymerisation of monomers derived from (substd.) (meth)acrylic acid or esters, where 20-40% of the monomer is a hydroxyalkyl (meth)acrylate, at 90-200 deg.C, in presence of a solvent suitable for high solids coating appln., with a solvent: monomer ratio of 3-0.1:1, in presence of 0.5-10 wt.%, w.r.t. monomer, of an at least 5C tert. alkyl hydroperoxide and/or deriv. (peroxy ketal, dialkyl peroxide, peroxyester or monoperoxy-carbonate), with 1 h half-life temp. of 50-190 deg.C, the initiator and monomer, alone or in combination, are added at a programmed rate so that the rate of addn. corresponds to the rate of decomposition of monomer and initiator during at least 3 h, at the end of the addn the monomer conversion is at least 90-95%, and the polymer prod. has Mn not above 4000, Mw/Mn ratio 1.5-3.0, Mz/Mn ratio 2-5, and at least 60% solids content.
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