Sumitomo Rubber Industries Limited

Kao Corporation

Nitto-denko Corporation

Fuji Latex Co., Ltd.

Higashi Kagaku Co., Ltd.

Eiji Kanamaru

Masaharu Hayashi

Yasuyuki Tanaka

Toshiaki Sakaki

Kazuhiko Shibata

Atsuko Kawasaki

Shinichi Nakade

Akihito Kuga

Kenichi Ikeda

Yoshiaki Miyamoto

Atsuko Ochi

Yuji Nishida

Kazuhiro Sekiguchi

Jitladda Tangpakdee

Tadashi Mihara

A method of producing a particulate natural rubber, which comprises adding an inorganic salt to a serum obtained by centrifugal separation of a natural rubber latex in the amount enough to cause separation of a particulate natural rubber component in the serum, thereby to isolate the particulate natural rubber component as a cream component.

Method of producing particulate natural rubber

Process for preparing deproteinized natural rubber latex molding and

Described is a process for the production of depolymerized natural rubber, which makes it possible to obtain, at high reaction efficiency, of depolymerized natural rubber in the liquid form and having a narrow molecular weight distribution; and also a process for the production of depolymerized natural rubber which is free from odor or coloring peculiar to natural rubber and is also free from the danger of immediate allergy derived from protein. The process according to the present invention comprises adding a carbonyl compound to a natural rubber latex, and then subjecting the resulting natural rubber to air oxidation in the presence of a radical forming agent or adding a carbonyl compound to the latex of deproteinized natural rubber and then subjecting the deproteinized natural rubber to air oxidation optionally in the presence of a radical forming agent.

Production process of depolymerized natural rubber

A depolymerized natural rubber having a number-average molecular weight of from 2,000 to 50,000 obtained by the depolymerization of a deproteinized natural rubber. A process for the preparation of a depolymerized natural rubber comprises dissolving a deproteinized natural rubber into an organic solvent so as to give a concentration of from 1 to 30% by weight and then carrying out air oxidation of the resulting solution in the presence of a metallic catalyst. The depolymerized natural rubber can provide the same physical properties as ordinary vulcanized rubbers, exhibits no odor or color characteristic to natural rubbers and causes no immediate allergy induced by protein.

Depolymerized natural rubber and process for preparation thereof

There are provided a deproteinized natural rubber latex which comprises a purified product of proteolytically treated natural rubber latex and contains fine particles of natural rubber latex, a deproteinized natural rubber which comprises a dehydrated product of the deproteinized natural rubber latex, and a process for the production of deproteinized natural rubber latex which comprises subjecting a latex solution prepared by (1) adding water and/or a surfactant to a natural rubber latex and then proteolytically treating the resulting latex solution or (2) proteolytically treating a natural rubber latex and then adding water and/or a surfactant to the treated natural rubber latex, to purification using a rotary plate membrane separation apparatus. The deproteinized natural rubber latex contains substantially no protein, is excellent in film-forming property, and provides a raw rubber film having excellent green strength, and the process can produce the deproteinized natural rubber latex in a high yield with high production efficiency.

Deproteinized natural rubber latex and its production process

Growing community of inventors

Tokyo, Japan

Eiji Kanamaru