Shin-etsu Chemical Co., Ltd.

Shin-etsu Bio., Inc.

The Institute of Physical and Chemical Research

Kaname Inoue

Richard W Armentrout

Motohide Yamazaki

Kanji Murofushi

Tadashi Amano

Shigehiro Nagura

Jun Watanabe

Hajime Kitamura

Isao Endo

Makoto Ooura

Tohru Yokota

Masakuni Yamamoto

Shoji Ichinohe

Kenichi Isobe

Tamaki Iida

Takeji Yanagisawa

Ryozo Tanizawa

Hideyuki Asou

In a process for producing vinyl chloride polymers including polymerization of vinyl chloride or a monomer mixture containing it in an aqueous medium using a polymerization initiator, the polymerization is carried out in the presence of a chelating agent. The chelating agent is capable of chelating iron (II) and iron (III). This process makes it possible to prevent polymer scales from adhering to, e.g. baffle surfaces facing inner walls of the polymerization vessel, which has been hitherto difficult to do so, and less cause initial discoloration of polymer products to improve quality. It is more effective to use a polymerization vessel previously provided with coating films of a polymer scale preventive agent on the inner walls of the polymerization vessel and the other portions with which monomers come into contact in the course of polymerization.

Process for producing vinyl chloride polymer in the presence of a chelating agent

In a process for producing vinyl chloride polymers including polymerization of vinyl chloride or a monomer mixture containing it in an aqueous medium using a polymerization initiator, the polymerization is carried out in the presence of a chelating agent, The chelating agent is capable of chelating iron (II) and iron (III). This process makes it possible to prevent polymer scales from adhering to, e.g. baffle surfaces facing inner walls of the polymerization vessel, which has been hitherto difficult to do so, and less cause initial discoloration of polymer products to improve quality. It is more effective to use a polymerization vessel previously provided with coating films of a polymer scale preventive agent on the inner walls of the polymerization vessel and the other portions with which monomers come into contact in the course of polymerization.

Process for producing vinyl chloride polymer, with iron chelates in

Disclosed is a method for selecting a mutant strain belonging to the genus Streptomyces which is a hyper-producer of Streptovaricin C superior to those know heretofore. This is accomplished by first subjecting a natural strain of Streptomyces spectabilis to conditions so as to isolate organisms which are streptovaricin resistant. The streptovaricin resistant organisms thus isolated are then subjected to mutagenesis and then cultured. The colonies which are asporogenous are individually cultured in fermentation batches such that the strains take the form of pellets of varying sizes and colors. From the batch having the most heterogeneous mixture of pellets, the smallest pellet or the pellet(s) having the deepest color (usually deep red or crimson) is isolated. We have discovered that the strain of this pellet has a high likelihood of being a hyperproducer of streptovaricin. The strain of this pellet may then be subjected to fermentation conditions to produce streptovaricin. The nutrient broth containing fumaric acid or water-soluble salts thereof, and adsorbent polymer beads and the streptovaricin produced are recovered in the usual manner. In another embodiment, the fermentation may be carried out in a nutrient broth wherein fumaric acid or its water-soluble salts are deliberately excluded to achieve even higher productivity.

Streptomyces spectabilis strains employed for producing streptovaricin C

A method for separation and recovery of polymeric beads from an antibiotic fermentation broth comprising suspending a mixture of the beads and any inherent mold from the fermentation in an aqueous solution having a specific gravity which is effective to cause the beads to form a discrete layer at or on the surface of the solution, separate and apart from the mold. The separate layer of the beads may then be easily removed from the liquid by a conventional physical methods.

Process for producing antibiotics

A method for producing streptovaricin by culturing a streptovaricin producing strain in the presence of a nonionic adsorbent. This procedure substantially increases the production efficiency of the streptovaricin. A second embodiment wherein the streptovaricin producing strain is produced in the presence of fumaric acid or its water soluble salts to provide improvements in production efficiency is also disclosed.

Process for preparation of streptovaricin

Process for preparing and selecting hyperproducing microorganism strains

Process for producing streptovaricin C

Process for producing antibiotic streptovaricin

A method for selecting hyper-producing strains of streptovaricin C by culturing streptomyces spectabilis and separating the asporogenous colonies. The asporogenous colonies are then separately cultured and tested for streptovaricin productivity. Those colonies having the highest productivity may then be easily selected.

Microorganism employed for producing streptovaricin

A method for selecting hyper-producing strains of streptovaricin C by culturing Streptomyces spectabilis and separating the asporogenous colonies. The asporogenous colonies are then separately cultured and tested for streptovaricin productivity. Those colonies having the highest productivity may then be easily selected.

Process for producing streptovaricin

A composite polymeric material having a high permeability to oxygen is proposed comprising a vinyl chloride moiety, an organosilicon moiety and, optionally, a third polymeric moiety. Such a composite polymeric material can be prepared in several ways including copolymerization of vinyl chloride monomer, a polymerizable organosilicon compound and, optionally, a third monomer, graft-polymerization of a polymerizable organosilicon compound on to a polyvinyl chloride resin, graft-polymerization of vinyl chloride on to an organopolysiloxane, graft-copolymerization of vinyl chloride and a polymerizable organosilicon compound on to a third polymer and blending of the respective polymeric components.

Composite polymeric material comprising vinyl chloride and organosilicon

The invention provides a formulation of a vinyl chloride resin-based composition suitable for preparing floppy disc jackets having high heat resistance with a Clash-Berg temperature of 75.degree. C. or higher comprising, as the essential components, (A) a copolymer of viny chloride with a N-substituted maleimide as the comonomer, optionally in combination with a homopolymeric polyvinyl chloride resin, (B) an impact-strength improving agent which is preferably a vulcanizable synthetic rubber and (C) carbon black.

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Kawasaki, Japan

Kaname Inoue