GB1141272A - Process for the preparation of ionogenic copolymers - Google Patents

Abstract

1,141,272. lonogenic copolymers. STAMICARBON N.V. 9 Sept., 1966 [14 Sept., 1965], No. 40469/66. Heading C3P. Ionogenic copolymers are prepared by reacting ethylene and a salt of an α,#-olefinically unsaturated mono- or dicarboxylic acid at a pressure of over 1200 atmospheres and at a temperature between 150‹ and 300‹ C. in the presence of a source of free radicals, the reaction conditions being such that at least a part of said salt forms a homogeneous phase with the ethylene. The ionogenic copolymers are defined as copolymers derived from at least 50 mole per cent of ethylene and from 0.2 to 25 mole per cent of an α,#-olefinically unsaturated carboxylic acid having one or two carboxyl groups, and possibly also from one or more other polymerizable unsaturated monomers, the said copolymers containing one or more metal ions, the valency of which is 1, 2 or 3 if the acid is monobasic or 1 if the acid is dibasic, the proportion of the metal ion present being sufficiently large to neutralize at least 10% of the carboxylic acid. The process is preferably carried out in a solvent for the salt, the solvent also completely or partially dissolving in the ethylene when containing the salt dissolved in it. Preferred solvents are oxygen-containing compounds, e.g. alcohols, ketones, ethers and esters. Particularly preferred are esters containing 2 to 8 carbon atoms per molecule and derived from saturated aliphatic carboxylic acids and saturated aliphatic alcohols, e.g. ethyl acetate. Water may be used if the polymerization is carried out at very high pressure, e.g. greater than 2000 atmospheres. The reaction mixture may also contain the corresponding acid or another unsaturated acid. In the examples sodium acrylate and sodium acrylate/ acrylic acid are used. Capryloyl peroxide is used as the free radical source and propane as a chaintransfer agent.