Shin-Etsu Chemical Co., Ltd.

Takashi Kobayashi

Tadashi Amano

Hideshi Kurihara

Yoshitaka Okuno

Toshio Shinohara

Manabu Furudate

Tomohiro Inoue

Yoshitsugu Eguchi

Tohru Nishikawa

Yasuhiro Takahashi

Ryuichi Saito

Genji Noguki

Tomohisa Suzuki

Yoshinori Nakahara

Fumiaki Adachi

Hitoshi Nakajima

Ichiro Hara

Tadaaki Kurokawa

Fujio Sato

The present invention relates to a dispersion liquid of titanium oxide-tungsten oxide composite photocatalytic fine particles that is characterized by having two types of photocatalytic fine particles dispersed in an aqueous dispersion medium, the fine particles including i) fine particles of titanium oxide that contain a peroxotitanium component and a copper component and ii) fine particles of tungsten oxide. The present invention can provide a dispersion liquid and the like that can be used to conveniently manufacture a photocatalytic thin film that demonstrates photocatalytic activity even within visible light (400-800 nm) only, exhibits high antibacterial performance, is highly durable, and wherein the state of copper coordination is stable against exposure to heat and ultraviolet rays and is not easily modified. The dispersion liquid is a dispersion liquid of titanium oxide-tungsten oxide composite photocatalytic fine particles that contains copper-containing titanium oxide fine particles.

Dispersion liquid of titanium oxide-tungsten oxide composite photocatalytic fine particles, production method for same, and member having photocatalytic thin film on surface thereof

It is possible to obtain a visible light-responsive photocatalytic nanoparticle dispersion liquid containing copper-containing titanium oxide nanoparticles by subjecting an aqueous peroxotitanic acid solution containing a copper compound to hydrothermal reaction for crystallizing the aqueous solution by means of heat under high pressure. The visible light-responsive photocatalytic nanoparticle dispersion liquid thus obtained exhibits excellent dispersion stability of titanium oxide nanoparticles within a water-based dispersion medium even when left in a cold and dark indoor area for a long period of time, expresses photocatalytic activity even in visible light (400 to 800 nm) alone, and can easily create a photocatalytic thin film which is extremely transparent and exhibits excellent durability, and in which the state of copper coordination when exposed to heat or ultraviolet rays is stable and cannot be easily modified.

Visible light-responsive photocatalytic nanoparticle dispersion liquid, method for producing same, and member having photocatalytic thin film on surface

A process for producing a vinyl chloride polymer, including the steps of (a) subjecting a vinyl chloride monomer alone or a monomer mixture containing a vinyl chloride, to suspension polymerization in water; (b) subjecting the resultant vinyl chloride polymer slurry to stripping to remove an unreacted monomer remaining therein; and (c) dehydrating the polymer slurry having been subjected to stripping. In the polymerization step (a), the ratio of water/monomer is set in a weight ratio of from 0.80 to 1.50, and the viscosity at 20&deg; C. of the polymer slurry to be fed to the stripping step is previously kept adjusted to 0.30 Pa&middot;s or lower. In the stripping step (c), the residual unreacted monomer in the polymer slurry can efficiently be removed using steam in a smaller quantity, thus the vinyl chloride polymer can be produced at a high productivity.

Process for producing vinyl chloride polymer with low residual monomer

A process for regenerating unreacted vinyl chloride monomers is provided which has the step of compressing by means of an compressor an unreacted vinyl chloride monomer recovered from a process of vinyl chloride polymer production; compressing the same in contact with a lubricating oil fed into the compressor. In this process, the lubricating oil contains a polymerization inhibitor. Hence, even when this lubricating oil is circulated and reused as a lubricating oil after its separation from the unreacted vinyl chloride monomer, any vinyl chloride monomer remaining in the lubricating oil can effectively be kept from polymerizing in lubricating-oil circulation lines.

Process for regenerating unreacted vinyl chloride monomers recovered

Process for producing vinyl chloride polymer

The present invention provides a method of producing vinyl chloride polymers, including the steps of subjecting vinyl chloride monomer or a mixture of monomers containing vinyl chloride monomer to suspension polymerization reaction in an aqueous medium within a polymerization vessel equipped with a reflux condenser, and subsequently, after the completion of the polymerization reaction, recovering any unreacted monomer, wherein foam generated on the surface of the liquid phase inside the polymerization vessel is eliminated by discharging a high pressure water having a pressure of 20 kg/cm.sup.2 or more substantially linearly to the surface of the liquid phase. The high pressure water discharging is carried out at the polymerization step, particularly from the time when operation of the reflux condenser begins, and/or at the recovery step. A vinyl chloride polymer is thus obtained without the splashing of foam over the gaseous phase section of the polymerization vessel, regardless of whether the heat removal rate of the reflux condenser, or the recovery rate per unit time for the unreacted monomer are increased.

Method of removing foam during polymerization of vinyl chloride polymers

Novel 1,1,2,2-tetramethylpropylperoxy esters are provided. They are useful as a polymerization initiator in polymerizing vinyl chloride, vinylidene chloride and vinyl acetate monomers, with the advantage of completing polymerization within a short time.

1,1,2,2-tetramethylpropylperoxy esters and method for preparing vinyl

A vinyl chloride polymer is prepared through suspension polymerization of a vinyl chloride monomer in the presence of a polymerization initiator in a reactor. The reactor is charged with up to 4/5 of the overall monomer charge to initiate polymerization. Polymerization is carried out under a certain saturated vapor pressure of P1 kgf/cm.sup.2 at a preset polymerization temperature. When the internal pressure of the reactor declines to P2 kgf/cm.sup.2, the remainder of the overall monomer charge is continuously fed to the reactor so as to maintain the internal pressure within the range of (P1-.DELTA.P) wherein .DELTA.P=P1-P2 ranges from 0.1 to 2.0 kgf/cm.sup.2. A vinyl chloride polymer having a high degree of polymerization is efficiently produced while alleviating the load of heat removal.

Process for preparing vinyl chloride polymer under specified vapor

Silicon-containing peroxyester compounds, for example, represented by the following formula: ##STR1## useful as a polymerization initiator, which compounds can produce vinyl chloride polymers having a high quality in a high yield and in a short reaction time.

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Kamisu, Japan

Takashi Kobayashi