Method for producing transparent plastic molded articles
 This invention provides a simple and advantageous method for producing plastic moldings with good surface gloss, very excellent transparency and high stiffness from crystalline polypropylene sheets manufactured by a generally employed industrial method without adversely affecting mechanical strength, shape retention at high temperatures and other properties according to a thermoforming process. This invention, more specifically, concerns a method for producing transparent polypropylene molded articles, characterized by heating a polypropyleneretention at high temperatures and other properties according to a thermoforming process. This invention, more specifically, concerns a method for producing transparent polypropylene molded articles, characterized by heating a polypropylene sheet at a temperature higher than the melting point thereof, stretching it by more than 5%, rapidly cooling it to a temperature of not more than 120.degree. C, and then subjecting the thus treated sheet to thermoforming at a temperature below the melting point of the sheet. 
Sumitomo Bakelite Company Limited
B B
B29C B29C
inventional inventional
Kyosuke Masahiro
Miki Takeuchi