RESIN MOLDING MATERIAL AND THE MOLDING METHOD THEREOF AS WELL AS ROTARY-HEAD DRUM DEVICE MANUFACTURED BY USING THE MOLDING MATERIAL

摘要

A RESIN MOLDING MATERIAL CONTAINS A PPS RESIN AS A BASE MATERIAL AND A FILLING MATERIAL FOR IMPROVING THE SLIDING PROPERTY OF A MOLDED PRODUCT. THE AVERAGE MOLECULAR WEIGHT OF THE PPS RESIN IS SET TO NOT MORE THAN 20000, AND THE VISCOSITY AT 300° OF THE PPS RESIN TO WHICH THE FILLING MATERIAL HAS BEEN ADDED IS SET IN THE RANGE OF 500 POISE TO 2000 POISE. DRUMS, WHICH HAS SURFACES ON WHICH THE MAGNETIC TAPE SLIDES, ARE INJECTION-MOLDED BY USING SUCH A RESIN MOLDING MATERIAL. THIS MAKES IT POSSIBLE TO EASILY EXPOSE THE FILLING MATERIAL ON THE MOLDED SURFACE. THEREFORE, IT BECOMES POSSIBLE TO PROVIDE A DRUM THAT IS SUPERIOR IN THE PRECISION, DIMENSION STABILITY AND SLIDING PROPERTY, WITHOUT THE NEED FOR SECONDARY MACHINING PROCESSES SUCH AS POLISHING.