| 摘要 |
PURPOSE:To enable a molding excellent in crank resistance to be produced by molding a thermoplastic resin A with high crystallinity index and a thermoplastic resin B having low crystallinity index and the larger viscosity value in molten state at molding temperature than that of the resin A, at a specified strain rate of molten resins when they pass through the mold gate. CONSTITUTION:Since crystalline thermoplastic resin A provides the higher crack- resistance and excellent appearance of a molding with the increase of crystallinity index of said resin A, the crystallinity index of crystalline thermoplastic resin is made to be 20% or more. The compounding rate of crystalline thermoplastic resin A into molding material for obtaining the thermoplastic resin molding with crack resistance is made to be 2-45wt%. On one hand, as thermoplastic resin B, for example the resin composition of aromatic vinyl-vinyl cyanide type having 20% or less crystallinity index is used. The compounded amount of the resin B is made to be in the range of 98wt%-55wt%. The viscosity of molten resin B is made to be larger than that of the molten resin A at the molding temperature. In normal injection molding, for the mixture of the resin A with the resin B, the strain rate at the time when the molten resins pass through the mold gate at the molding temperature of a molding machine is made to be 1X10<5>sec<-1> or more to form the crystalline plastic. Compound layer on the surface of a molding.
|
