THICKENABLE ALKYL ACRYLATE LATICES

摘要

1355686 Alkyl acrylate polymer latexes B F GOODRICH CO 21 July 1971 [22 July 1970] 34119/71 Headings C3P and C3G Aqueous acrylate polymer latexes are prepared by first polymerizing in an aqueous medium at a pH of less than 7 a mixture of 50-99À8% (based on the weight of total monomers used) of at least one C 1 -C 8 -alkyl acrylate or methacrylate and 0À1-10% of a glycidyl ester of an ethylenically unsaturated carboxylic acid or a glyidyl ether containing olefinic unsaturation until at least about 50% by weight of the monomers have been polymerized to form a base polymer, and then overpolymerizing (graft polymerizing) with 0À1-10% (based on total monomers) of an olefinically unsaturated carboxylic acid (or anhydride thereof) containing an olefinic bond in anα,#-position with respect to the carboxyl group or containing a terminal methylene grouping. The glycidyl monomer may be, for example, glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, glycidyl abietate, glycidyl vinyl ether, glycidyl allyl ether, glycidyl isopropenyl ether, glycidyl methallyl ether or glycidyl butenyl ether. The monomer mixture in the first stage may also contain one or more other monomers, e.g. conjugated dienes, alpha-olefins, vinyl and vinylidene halides, vinyl esters, vinyl aromatic compounds, alkyl vinyl ethers, acrylic, methacrylic or ethacrylic acid and nitriles, amides and N-alkyl amides thereof. Specified acid monomers for overpolymerization are acrylic acid and itsα-methyl,α-ethyl,α-chloro andα-cyano derivatives, crotonic acid, # - acryloxy - propionic acid, hydrosorbic acid, sorbic acid,α-chlorosorbic acid, cinnamic acid, #-styryl-acrylic acid, hydromuconic acid, itaconic acid, citraconic acid, fumaric acid, mesaconic acid, muconic acid, glutaconic acid, aconitic acid and maleic anhydride; monomers as used in the first stage may also be added in the overpolymerization step as well as cross-linking monomers such as methylene - bis - acrylamide, ethylene glycol dimethacrylate, diethylene glycol diacrylate, pentaerythritol tetraallyl ether and divinylbenzene. Polymerization can be initiated with conventional peroxide, nitrile and redox catalysts, and may be effected in the presence of an emulsifier, preferably an anionic or nonionic emulsifier. The viscosity of the latexes is considerably increased, simply by raising the pH of the latexes by addition of a base, e.g. an alkali hydroxide, ammonia or an amine. The thickened latexes are useful in impregnating, coating and laminating applications.