Patent ID: 8153036

Claim:
A process for producing a thermoplastic polymer powder, the process comprising subjecting an acrylic block copolymer (I) to an underwater cutting process to obtain a thermoplastic polymer powder, wherein the acrylic block copolymer is a triblock copolymer (B)(A)(B) wherein block (A) comprises structural units originating from an acrylic ester; and each block (B) comprises structural units originating from a methacrylic ester, wherein the thermoplastic polymer powder has a complex dynamic viscosity η*(5) of 5.0×10 3 Pa·s or less, the viscosity η*(5) being measured under conditions of a temperature of 250° C. and an angular frequency of 5 rad/sec; wherein the thermoplastic polymer powder has a Newtonian viscosity index n of 0.50 or less, the Newtonian viscosity index n being represented by the following equation (1): n =log η*(5)−log η*(50) (1) wherein n represents the Newtonian viscosity index, η*(5) represents the complex dynamic viscosity (unit: Pa·s) measured under conditions of a temperature of 250° C. and an angular frequency of 5 rad/sec, and η*(50) represents the complex dynamic viscosity (unit: Pa·s) measured under conditions of a temperature of 250° C. and an angular frequency of 50 rad/sec; and wherein the thermoplastic polymer powder has an average particle diameter of 1 mm or less.