LOW-MOLECULAR WEIGHT (METH)ACRYLIC ACID (SALT)-BASED POLYMER, METHOD FOR PRODUCING THE SAME AND APPLICATION THEREOF

摘要

PROBLEM TO BE SOLVED: To obtain a low-molecular weight (meth)acrylic acid (salt)-based polymer having an excellent color tone and to provide a method for producing the same and its application. SOLUTION: This method comprises polymerizing a monomer component composed of 100-95 mol% of a monoethylenic unsaturated monomer of a 3-6C monocarboxylic acid (salt) (a) and 0-5 mol% of a monoethylenic unsaturated monomer (b) copolymerizable with the monomer (a) (the total of the components (a) and (b) is 100 mol%) in the presence of an alkali substance in a highly concentrated aqueous solution. Both a sulfate and hydrogen peroxide are used as polymerization catalysts. The total amount of the alkali substance used is S99 mol% of the amount required for neutralizing the whole acid groups of the monomer component. The drip of hydrogen peroxide is finished within ten minutes or more earlier than the time when the drip of the monomer is finished and/or the amount of hydrogen peroxide dripped before the start of the drip of the monomer component is controlled to <=10% the whole amount of hydrogen peroxide added. The application of the polymer is for a detergent composition, a water treatment agent, a pigment dispersant, or the like.