Verfahren zur Herstellung von fuer Beschichtungszwecke geeigneten haertbaren Polymeren

摘要

A storage-stable and internally catalyzed heat-hardenable organic solvent-soluble nongelled interpolymer of an amide of an ethylenically unsaturated carboxylic acid and a poly-unsaturated carboxyl - terminated polyester resin, the carboxyl termination consisting essentially of saturated polycarboxylic acid incorporated in the polyester resin, amido hydrogen atoms of the interpolymer being replaced by the structure where R represents hydrogen, furyl or a saturated lower aliphatic hydrocarbon radical containing up to 10 carbon atoms and R1 represents hydrogen or an alkyl, alkoxyalkyl or aryl radical containing up to 10 carbon atoms, and the carboxyl-terminated polyester resin providing the interpolymer with an acid value of from44 to 30, is prepared by heating the amide and the unsaturated polyester resin in the presence of an aldehyde or aldehyde-yielding substance, and, if employed, other monoethylenically unsaturated monomers, in an organic solvent in the presence of an alkaline catalyst and a free-radical generating polymerization catalyst. At least 0.1% of alkaline catalyst is used, based on the weight of the monomers being copolymerized, the preferred alkaline catalysts being tertiary amines. The preferred amide comonomer is acrylamide and it is preferably used in an amount to give 5 to 45% by weight of amide component in the interpolymer. Lists of amide comonomers, unsaturated polyester resins, saturated polycarboxylic acids, aldehydes and aldehyde-yielding substances, ethylenically unsaturated comonomers and catalysts are given. In the examples the polyester resins used are prepared by reacting crotonic acid, dehydrated castor oil fatty acids, isophthalic acid, glycerine, a resinous polyol which is 1,11-isopropylidene bis-(p-phenyleneoxy) - di - 2 - propanol phthalic anhydride, azelaic acid and optionally trimellitic anhydride, and the interpolymers are formed by reacting them with a mixture of acrylamide, styrene, methyl methacrylate, ethyl acrylate and 2-ethylhexyl acrylate in the presence of a 40% formaldehyde solution in n-butanol. The interpolymers may be blended with titanium dioxide or titanium dioxide plus talc, silica and pigments.