The Japan Steel Works, Ltd.

Nagase Co., Ltd.

Tadamoto Sakai

Shigeki Inoue

Kazuyuki Nakamura

Fumiaki Tsuda

Mitsuo Nagai

Kunihiko Koyanagi

Yukihiro Sumihiro

Noriaki Hashimoto

Rika Miyoshi

Kayoko Yokota

Hiroyuki Tokushige

Keiichiro Hirao

Akira Kosaki

A process for producing polylactic acid includes the steps of polycondensing lactic acid to a lactic acid prepolymer having a weight-average molecular weight of 10,000-50,000 in a batch-type polymerization reactor, and polycondensing the lactic acid prepolymer to lactic acid polymer having a weight-average molecular weight of at least 100,000 by means of a screw-type extruder.

Process for producing lactic acid polymers and a process for the direct

A method of reclaiming a plastic product having a paint film, including the steps of: obtaining crushed particles by crushing a plastic product having a paint film into particles of a predetermined size; supplying the crushed particles to a screw-type extruder; kneading and fusing the crushed particles while supplying water thereto; and obtaining a plastic by discharging a gas produced by decomposing the paint film and vaporized water.

Method of reclaiming plastic product with paint film

A method of producing fiber reinforced plastic moldings. The method includes the steps of: supplying a thermosetting resin component and a thermoplastic resin component into a twin screw extruder; kneading the thermosetting resin component and the thermoplastic resin component into each other in the extruder to produce a fused material in which fine particles of the thermoplastic resin component are micro-dispersed in a matrix of the thermosetting resin component; suppling a liquid monomer into the extruder so that the liquid monomer is mixed with the fused material so as to adjust the viscosity of the fused material to be low; suppling a reaction initiator into the extruder so that the reactive initiator is mixed with the fused material at a temperature not higher than a reaction initiation temperature so as to produce a reactive kneaded material; continuously discharging the reactive kneaded material from a die of the extruder so as to apply the reactive kneaded material onto a long fiber mat; simultaneously pressing and cooling the mat coated with the reactive kneaded material to shape the mat into a sheet; cutting the sheet into pieces having a predetermined length; shaping and curing the thus cut pieces into moldings of a desired form by means of a press molding machine.

Method of producing fiber reinforced plastic moldings

A method of forming a composite material involves feeding materials to a kneader, kneading the materials, and injecting them from the kneader into a mold. The kneader is formed by a screw-type extruder having an ejection outlet at one end for extrusion into the mold. Various input ports are located axially along the extruder. Materials are fed into the kneader beginning at the inlet port most remote from the outlet end and proceeding successively to the inlet port nearest the outlet end. The materials are fed in successive order from those with the highest viscosity and lowest reactivity relative to the materials with the highest reactivity and lowest viscosity. For example, thermoplastic is fed to the inlet most remote from the outlet, and thermosetting resin is fed to the inlet nearest the outlet. In another aspect of the invention, in which thermoplastic and thermosetting resins are employed in roughly comparable amounts, an 'island-in-sea' structure is desired. This structure is achieved by agglomerating thermoplastic material having a particle diameter of 0.05-0.5 .mu.m into particles of 10-1000 .mu.m diameter prior to kneading, then introducing the thermoplastic material into the kneader. The thermoset material is then added from least reactive and most viscous to most reactive and least viscous.

Method of producing molded resin article

Synthetic macro-molecule materials are continuously supplied into the cylinder of an extruder so that said synthetic macro-molecule materials are internally heated by the shearing as well as kneading action of the screw to which they are subjected and externally heated by the heat transmitted through the wall of the cylinder of said extruder from an outside heat source so that said synthetic macro-molecule materials are continuously thermally decomposed within said cylinder, thereby vapourized thermally decomposed products are fed to the condensing means through one or more discharge orifices provided in said cylinder to be recovered there as thermally decomposed products having low molecular weights.

Method for continuously thermally decomposing synthetic macro-molecule

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Hiroshima, Japan

Tadamoto Sakai