Resin composition based on crystalline polypropylene

Abstract

Present invention provides a resin composition bases on crystalline polypropylene which does not suffer from occurrence of flow mark and rashes caused from polymer gel upon molding and, thus, can produce molded articles exhibiting superior appearance and having excellent mechanical strength, such as flexural modulus and so on, together with better flowability upon the molding and which can be obtained at a lower cost by choosing starting materials of high productivity. The resin composition based on crystalline polypropylene according to the present invention comprises (a) 3-65% by weight of a component soluble in paraxylene of 23° C. (b) 35-97% by weight of a component soluble in paraxylene of 135° C. and insoluble in paraxylene of 23° C. and (c) 0-30% by weight of a component insoluble in paraxylene of 135° C., wherein the component (a) soluble in paraxylene of 23° C. is composed substantially of an elastomeric constituent (a1) having a content of styrene or its derivative in the range of 0-35% by weight and an intrinsic viscosity [η] determined in decalin at 135° C. in the range of 0.1-5 dl/g, the component (b) soluble in paraxylene of 135° C. and insoluble in paraxylene of 23° C. is composed substantially of a crystalline polypropylene constituent (b1) having an isotactic pentad proportion (mmmm) of 97% or higher, a molecular weight distribution expressed by weight-average molecular weight/number-average molecular weight (Mw/Mn), determined by gel permeation chromatography (GPC), of 6 or higher and a molecular weight distribution expressed by z-average molecular weight/weight-average molecular weight (Mz/Mw) of 6 or higher and the component (c) insoluble in paraxylene of 135° C. is composed substantially of a filler (c1).

Dependencies are inferred from the claim text.