PURPOSE: To obtain a composition for injection molding which can form molded items being nearly free of deformation and having excellent mechanical strength, by adding mica powder and a silicic acid filler to a thermoplastic polyurethane obtained from polybutylene terephthalate and a polyisocyanate.

CONSTITUTION: A polybutylene terephthalate having an inherent viscosity of 0.2W 0.6 and a hydroxy group at its terminal, and a polyisocyanate are reacted, for example, in a high-viscosity reactor to obtain a thermplastic polyurethane. 100pts.wt. Above-mentioned polyurethane is blended with 10W100pts.wt. mica powder having a particle size of 100 mesh or less and 10W100pts.wt. silicic acid filler selected from among nonalkali glass beads, nonalkali glass powder, milled glass, etc. having an average particle size of 200μ or less, and the blended composition is heated and milled to obtain the titled composition.

EFFECT: The thus-obtained composition can form molded items having excellent heat resistance, surface condition, and paintability and undergoing little reduction in the strength of a welded part. It has also only a small contraction ratio when molded.