PURPOSE: To obtain a PVC article, especially, rigid one, having a high softening point and good physical properties by blending a specified polyketone with PVC.

CONSTITUTION: A composition is made by blending (A) a polyketone being a linear polymer having an alternating structure of units derived from CO and units derived from an olefinically unsaturated compound with (B) a vinyl chloride resin in an extruder or the like. Component A is not a propylene/CO copolymer having a molecular weight of below 1,000 but an ethylene/propylene/ CO terpolymer having a molecular weight of 4×104 to 100×104, desirably, 6×104 to 15×104 and desirably having a propylene content in the range of 5-8 wt.%. Component B is desirably applied to a composition being especially an unplasticized (rigid) PVC (called UPVC). The A/B weight ratio is in the range of 1/10 to 10/1, desirably, 1/1.5 to 1.5/1. Component A is represented by the general formula (wherein R is H or a hydrocarbyl; and n is a large integer).