Acrylic Acid → Vinyl acetate methylacrylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 6240 parts water, 30 parts potassium persulfate, 18 parts sodium pyrophosphate, 30 parts 2-acrylamido-2-methyl-propane sulfonic acid and 48 parts sodium vinyl sulfonate was placed in a polymerization vessel. The mixture was heated to a temperature from 80° C. to 83° C. Beginning at 78° C., a mixture of 2685 parts methylacrylate, 2985 parts vinyl acetate, 309.3 parts of acrylic acid and 30 parts of t-dodecylmercaptan (1) and a solution of 60 parts potassium persulfate in 2940 parts of water (2) were fed into the vessel from separate containers. Feed 1 was added to the polymerization vessel in 2 hours and feed 2 was introduced into the polymerization vessel in 2.5 hours. After feed was completed, the temperature of the reaction mixture was increased to 90° C. and the mixture was maintained at 90° C. for 1.5 hours. The result was an aqueous dispersion of a copolymer having a K-value of 20. The dispersion was allowed to cool to 30° C. and a solution of 270 parts sodium hydroxide in 15,942 parts of water, fed into the vessel within a period of 1 hour. Following this, the mixture was allowed to react for 1 hour. A 20 percent aqueous solution of a partially saponified vinyl acetate-methylacrylate copolymer was obtained which had a pH value of 8.25 and a viscosity of approximately 24 mPa.s.

Herkunft & Nachweise