LUBRICANT FOR WARM MOLDING AND POWDER MIXTURE FOR WARM MOLDING METHOD FOR WARM MOLDING OF POWDER MIXTURE

摘要

PROBLEM TO BE SOLVED: To obtain high-density moldings in a warm molding region by using a lubricant for warm molding contg. polymer powder having a softening point lower than the max. value of a set preheating temp. and a solid lubricant and specifying the melt viscosity of the polymer powder in the max. value of preheating temp. ;SOLUTION: For example, the max. value of the preheating temp. is set at 150°C and polyethylene oxide of ≥1,000 centipoises in the melt viscosity at this temp. and lithium stearate as a solid lubricant capable of maintaining a solid phase at this temp. or above are selected, thereby constituting the lubricant for warm molding. The lubricant for warm molding is composed by using such polymer and lubricant. If the warm molding is executed at 150°C by using the resultant lubricant, the preheating temp. and the warm molding temp. may be made the same. The melt viscosity does not sharply drop with this polymer powder even if the temp. exceeds the softening point and, therefore, the setting of the preheating temp. within this range is possible. In addition, the sharp degradation of the lubricity does not arise even if the warm molding temp. is set by providing the temp. with a large difference to some extent.;COPYRIGHT: (C)1998,JPO