Mitsui Toatsu Chemicals, Incorporated

Mitsui Chemicals, Inc.

Seiichi Masuko

Ichisaburo Nakamura

Yasuyuki Hatakeyama

Keiichi Fukuda

Akihiro Yamaguchi

Akira Yamamoto

Keizaburo Yamaguchi

Hiroshi Okada

Yoshimatsu Naka

Akihiko Takahashi

Hideaki Takahara

Katsuhito Kohketsu

Yoshihiro Umeda

Kuniyuki Gotoh

Takehiko Mogi

Takehiko Kano

Hideyuki Itagaki

In a novel method of homo- or copolymerization of vinyl chloride, a specified coating agent is applied on the surfaces of the portions which will become into contact with the vinyl chloride monomer during the polymerization process. The coating agent is in a form of an aqueous solution of a modified condensation product of phenol and aldehyde, the pH of the solution being adjusted in a range that the product is dissolved at an ambient temperature upon coating of the solution and separates out of the solution upon being heated on the surfaces. The wall surface of the polymerization tank and the like is then coated with a thin film of the coating agent having a uniform thickness and being strongly adhered to the wall surface, thereby providing an excellent effect of preventing adhesion of the product polymer to the wall surface.

Method of preventing scale adhesion to the surfaces of a polymerization tank

A process is provided for the polymerization of vinyl chloride in a closed mode. According to the process, oxygen is caused to exist in a polymerizer, which is coated with an anti-fouling agent, during an operation in which the polymerization is repeated. The process according to this invention has made it possible to fully exhibit effects of the anti-fouling. This has in turn made it possible to achieve polymerization of vinyl chloride in the closed mode, leading to an improvement in productivity.

Polymerization process of vinyl chloride in the presence of oxygen

Method of preventing scale adhesion to the surfaces of a polymerization

Method of preventing scale adhesion to surfaces of polymerization tank

A heat resistant polyvinyl chloride copolymer or a heat and impact resistant polyvinyl chloride copolymer is prepared by conducting graft copolymerization of N-substituted maleimide on a vinyl chloride resin or a rubber containing vinyl chloride resin. The graft copolymerization reaction is carried out in the presence of a radical polymerizable monomer which is (1) liquid at the polymerization temperature, (2) capable of dissolving the N-substituted maleimide at the temperature, (3) 70.degree. C. or more in glass transition temperature of the polymer thereof, and (4) used in an amount sufficient to dissolve the N-substituted maleimide.

Heat resistant polyvinyl chloride copolymer and preparation process of

A method for polymerizing vinyl chloride comprises polymerizing vinyl chloride in an aqueous medium or bulk-polymerizing vinyl chloride, wherein the inner wall of a polymerizer and parts of devices which come in contact with the monomer during the polymerization are coated, prior to the polymerization, with a reaction product having a molecular weight ranging from 500 to 100,000, obtained by condensing a polyhydric phenol and sulfur dichloride in the presence of a Lewis acid as a catalyst. The amount of the polymer adhered to the polymerizer during polymerization of vinyl chloride is substantially lowered and the adhered polymer can be easily washed away through simple water washing according to the foregoing method. Moreover, the method does not adversely affect the reaction time and the quality of the resulting product at all.

Method for polymerizing vinyl chloride while inhibiting adhesion to the

Disclosed herein is a stripping tower adapted to remove unreacted vinyl chloride from a suspension or emulsion of a vinyl chloride resin after its polymerization reaction. The tower is a packed tower filled with a packing such as Tellerette packing. A condenser is provided in direct attachment to a top portion of the packed tower so that steam, which is discharged together with stripped monomeric vinyl chloride gas, is condensed in the condenser, separated from the monomeric vinyl chloride gas and then recirculated to the packed tower. Use of a packed tower as a stripping tower and steam as a stripping medium enjoys good removal efficiency of monomeric vinyl chloride but is accompanied by occurrence of a large volume of foams of a polyvinyl chloride slurry in the tower. Foams of the slurry eventually overflow from the top of the tower and do not permit any further continuation of the operation. Provision of the condenser in direct attachment to the top portion of the tower was found to be effective in suppressing the occurrence of foams, thereby permitting efficient removal of monomeric vinyl chloride.

Monomeric vinyl chloride stripping tower

In the polymerization of vinyl chloride, the adhesion of the resulting polymer to the walls can be prevented by previously applying a specific chemical to the inner walls of the polymerization tank and parts of the device to be contacted with the monomer during the polymerization. This specific chemical is a copolycondensate obtained by reacting a resol type phenol/formaldehyde precondensate with a nitrogen-containing compound selected from the group consisting of nitrophenols, nitrobenzoic acids, nitrobenzenesulfonic acids, aminophenols, aminobenzoic acids and aminobenzenesulfonic acids.

Polymerizing vinyl chloride in reactor treated with condensates

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Osaka, Japan

Seiichi Masuko