Process for terpolymer polyblends having high gloss and ductility

#It is known to graft diene rubber particles in an aqueous latex with alkenyl aromatic and alkenyl nitrile monomers to form conventional ABS polyblends.

#Such polyblends have used grafted rubber particles ranging from about 0.01 to 0.25 microns to obtain high gloss in formed articles. Polyblends having these small particles have not had high levels of toughness or high elongation at fail. U.S. Pat. No. 3,509,237 has taught that these deficiencies can be overcome by adding up to 30% by weight of grafted large rubber particles, based on total grafted rubber content of polyblend. Said particles having a size of about 0.8 to 2.0 microns or larger.

#The use of small and large grafted rubber particles or broad distributions of grafted rubber particles does improve toughness, however, gloss is lowered in proportion to the amounts of large particles used to gain toughness.

#The following examples are illustrative of the present process and are not meant to limit the scope or spirit of the invention.

#To a 250.0 parts of a latex of butadiene/acrylonitrile copolymer (93:7) containing 50.0 percent solids and with a gel content of about 75% approximately 1.0 part of rubber reserve soap as an emulsifier were added 70.0 parts water, 1.0 part rubber reserve soap and 1.0 part potassium persulfate.

#This emulsion was heated to 65.degree. centigrade with stirring and then there were added thereto over a period of about six hours 140.0 parts styrene, 60.0 parts acrylonitrile and 3.0 parts of terpinolene. The emulsion was held at temperature for one hour thereafter with stirring, cooled, coagulated by the addition of magnesium sulfate and the coagulant was then washed and dried. The resulting graft copolymer has a superstrate to substrate ratio of about 0.9:1.0 and a rubber particle size of about 0.25 micron.