High impact two-component polystyrene blends

Claim 1

A COMPOSITION CHARACTERIZED BY EXHIBITING EXCELLENT PROPERTIES SUCH AS IMPACT STRENGTH LOW TEMPERATURES AS WELL AS ROOM TEMPERATURES, SAID COMPOSITION CONSISTING ESSENTALLY OF A BLEND OF A. A MATRIX OF POLYMERS PREPARED FROM AT LEAST 90 WEIGHT PERCENT STYRENE MONOMER, ANY OTHER MONOMERS BEING OTHER ETHYLENICALLY UNSATURATED MONOMERS, POLYMERS HAVING A NUMBER AVERAGE MOLECULAR WEIGHT OF FROM ABOUT 50,000 TO 500,000: AND B. GRADED BLOCK COPOLYMERS OF THE TYPE AB IN WHICH A REPRESENTS ESSENTIALLY POLYMERIZED STYRENE, THE BALANCE OF SAID SEGMENT BEING POLYMERIZED BUTADIENE, AND B REPRESENTS ESSENTIALLY POLYMERIZED BUTADIENE, THE BALANCE OF SAID SEGMENT BEING POLYMERIZED STYENE THE WEIGHT RATIO OF TOTAL STYRENE TO TOTAL BUTADIENE IN A AND B BEING IN THE RANGE OF 15:85 TO 45:55, THE NUMBER AVERAGE MOLECULAR WEIGHT OF SAID BLOCK COPOLYMERS BEING FROM 100,000 TO 500,000, SAID GRATED BLOCK COPOLYMERS HAVING A PRINCIPAL GLASS TRANSITION TEMPERATURE OF ABOUT -94*C, 6*C,: COMPONENT (B) BEING DISPERSED IN COMPONENT (A) AS A DISCONTINUOUS PHASE OF PARTICLES OF WHICH AT LEAST 70 WEIGHT PERCENT HAVE DIAMETERS IN THE RANGE OF 0.2 TO 5 MICRONS AND THE TOTAL STYRENE UNITS IN COMPONENTS (A) AND (B) BEING FROM 75 TO 90 WEIGHT PERCENT OF THE TOTAL UNITS IN SAID COMPONENTS.

Claim 6

A method of making resins having excellent impact strengths, flexural moduli and heat distortion characteristics, particularly at low temperatures, comprising blending a mixture consisting essentially of A. a matrix of polymers prepared from at least 90 weight percent vinyl aryl monomers, any other monomers being other ethylenically unsaturated monomers, said polymers having a number average molecular weight of from about 50,000 to 500, 000; and B. graded block copolymers of the type AB in which A represents essentially polymerized styrene, the balance of said segment being polymerized butadiene, and B represents essentially polymerized butadiene, the balance of said segment being polymerized styrene, the weight ratio of total styrene to total butadiene in A and B being in the range of 15:85 to 45:55, the number average molecular weight of said block copolymers being from 100,000 to 500,000, said graded block copolymers having a principal glass transition temperature of about -94*C. + or -6*C.; component (B) being dispersed in component (A) as a discontinuous phase of particles of which at least 70 weight percent have diameters in the range of 0.2 to 5 microns and the total styrene units in components (A) and (B) being from 75 to 90 weight percent of the total units in said components.

Claim 7

A method of making resins having excellent impact strengths, flexural moduli and heat distortion characteristics, particularly at low temperatures, comprising blending a mixture consisting essentially of A. a matrix of polymers prepared from at least 90 weight percent vinyl aryl monomers, any other monomers being other ethylenically unsaturated monomers, said polymers having a number average molecular weight of from about 50,000 to 500, 000; and B. graded block copolymers of the type AB in which A represents essentially polymerized styrene, the balance of said segment being polymerized butadiene, and B represents essentially polymerized butadiene, the balance of said segment being polymerized styrene, the weight ratio of total styrene to total butadiene in A and B being in the range of 15:85 to 45:55, the number average molecular weight of said block copolymers being from 100,000 to 500,000, said graded block copolymers having a principal glass transition temperature of about -94*C. + or -6*C.; component (B) being dispersed in component (A) as a discontinuous phase of particles of which at least 70 weight percent have diameters in the range of 0.2 to 5 microns and the total styrene units in components (A) and (B) being from 75 to 90 weight percent of the total units in said components.