Dispersing stabilizer
AssigneeNippon Gohsei Kagaku Kogyo Kabushiki Kaisha
InventorsMotokazu Maruhashi, Kizo Ohnishi
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Abstract
A dispersing stabilizer including (A) a polyvinyl alcohol resin containing oxyalkylene groups and having a surface tension of 35 to 55 dyne/cm at 20.degree. C. as a 1% by weight aqueous solution, or said resin and (B) a water-soluble polymer or a polyvinyl alcohol resin having a low degree of hydrolysis and a low degree of polymerization. When using the dispersing stabilizer of the present invention, both of a porosity and a bulk density of a polyvinyl resin particle can be improved at the same time, and, in addition, a distribution of particle size and a uniformity of porosity can be further improved.
Claims2
A process for preparing a water-soluble copolymer having a dispersion stabilizing property, which comprises copolymerizing vinyl acetate and at least one unsaturated monomer containing 2 to 300 oxyalkylene groups to obtain a random copolymer and hydrolyzing the copolymer, wherein the content of oxyalkylene groups in the copolymer is 3 to 40% by weight based on the whole copolymer,
- and wherein the unsaturated monomer is at least one monomer selected from the group consisting of a monomer represented by the formula (I):
- ##STR7## wherein R is hydrogen or methyl, A is an alkylene group of 1 to 10 carbon atoms, a substituted alkylene group of 1 to 10 carbon atoms, R.sup.1 and R.sup.2 are hydrogen or an alkyl group of 1 to 10 carbon atoms, m is 0 or an integer of 1 or more and n is an integer of 1 to 300;
- a monomer represented by the formula (II):
- ##STR8## wherein R.sup.3 is hydrogen, an alkyl group of 1 to 10 carbon atoms, or ##STR9## H, and A, R, R.sup.1, R.sup.2, m, and n are as defined above;
- a monomer represented by the formula (III):
- ##STR10## wherein R, R.sup.1, R.sup.2, and n are as defined above;
- and a monomer represented by the formula (IV):
- ##STR11## wherein A, R.sup.1,R.sup.2, m, and n are as defined above.
Dependencies are inferred from the claim text.