Shin-etsu Chemical Co., Ltd.

Masaki Tabata

Mitsuo Narita

Hiroshi Umezawa

Atsushi Yoshida

Shuhei Ueda

Yukio Shibano

Atsushi Watabe

Satoru Miharada

Kazuhisa Hayakawa

Tsutomu Yamakawa

Yoshiaki Sasage

Shuji Tanaka

The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, the invention is a method for preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution in a bucket conveyor type contactor to generate a contact mixture, and draining the contact mixture; a method for preparing a cellulose ether comprising use of the alkali cellulose thus prepared; and an apparatus for preparing alkali cellulose comprising a bucket conveyor contactor comprising at least one inlet port for introducing pulp and an alkali metal hydroxide solution at one end and at least one outlet port for discharging a contact mixture wherein the pulp and the alkali metal hydroxide solution can be moved from one end to the other end while bringing them into contact with each other to generate the contact mixture; and a drainer for separating a cake from the contact mixture discharged from the outlet port.

Methods for preparing alkali cellulose and cellulose ether

The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, pulp and an excess alkali metal hydroxide solution are introduced continuously in a screw conveyor type contactor and brought into contact with each other in the screw conveyor type reactor. By changing at least one factor selected from the group consisting of a rotation speed of the screw conveyor, a screw pitch and a length of immersion zone, a ratio of an alkali to cellulose in the alkali cellulose obtained by draining is controlled. The alkali cellulose thus obtained is etherified into the corresponding cellulose ether.

The invention is an efficient method for preparing alkali cellulose having the low water content and a uniform alkali distribution therein. More specifically, the invention is a method for continuously preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution to generate a contact mixture and then draining the contact mixture by a centrifugal separator. The invention also includes a method for preparing cellulose ether comprising a step of etherifying the alkali cellulose.

A mixture containing methyldichlorosilane, tetrachlorosilane, and trichlorosilane is distilled to fractionate a fraction with a higher content of methyldichlorosilane than the mixture before distillation. Subsequently, the fraction thus fractionated is heated to disproportionate chlorine between methyldichlorosilane and tetrachlorosilane to disproportionate methyldichlorosilane into methyltrichlorosilane. Subsequently, the fraction after disproportionation containing methyltrichlorosilane is purified by distillation to separate high-purity trichlorosilane. Having a close boiling point to that of trichlorosilane (32&#xb0; C.), which is a target product to be purified by distillation, removal of methyldichlorosilane (boiling point of 41&#xb0; C.) has been difficult. The present invention removes methyldichlorosilane more easily by converting it into methyltrichlorosilane (boiling point of 66&#xb0; C.) through disproportionation of chlorine between methyldichlorosilane and tetrachlorosilane.

Method for producing trichlorosilane

The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, the invention is a method for preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution in a rotary feeder type contactor to generate a contact mixture, and draining the contact mixture; and a method for preparing cellulose ether comprising use of the alkali cellulose thus prepared; an apparatus for preparing alkali cellulose, comprising a rotary feeder comprising a cyclic housing comprising an inlet port and an outlet port, a cyclic contact drum being circularly rotatable along the housing in the housing and comprising a plurality of filter cells arranged in a circumferential direction, and a filtrate-discharging tube being disposed in a diameter direction inside of the cyclic contact drum and collecting the filtrate which has passed the filter, and a drainer for draining a cake discharged from the contactor.

The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, the invention is a method for preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution in a pipe type contactor to generate a contact mixture and draining the contact mixture; a method for preparing cellulose ether comprising use of the alkali cellulose; and an apparatus for preparing alkali cellulose, comprising a pipe type contactor having at least one inlet port at one end thereof for introducing pulp and an alkali metal hydroxide solution, and an outlet port at the other end for discharging a contact mixture, wherein the pulp and the alkali metal hydroxide solution are moved from one end to the other end while bringing them into contact with each other, and a drainer for separating a cake from the contact mixture discharged from the contactor.

A large-sized substrate having a diagonal length of not less than 500 mm and a ratio of flatness/diagonal length of not more than 6&#xd7;10is disclosed. By use of the large-sized substrate for exposure of the present invention, the exposure accuracy, particularly the register accuracy and resolution are enhanced, so that it is possible to achieve high-precision exposure of a large-sized panel. With the processing method according to the present invention, it is possible to stably obtain a large-sized photomask substrate with a high flatness, and since the CD accuracy (dimensional accuracy) at the time of exposure of the panel is enhanced, it is possible to perform exposure of a fine pattern, leading to a higher yield of the panel. Furthermore, by applying the processing method according to the present invention, it is also possible to create an arbitrary surface shape.

Large-sized glass substrate

A large-sized substrate having a diagonal length of not less than 500 mm and a ratio of flatness/diagonal length of not more than 6.0&#xd7;10is disclosed. By use of the large-sized substrate for exposure of the present invention, the exposure accuracy, particularly the register accuracy and resolution are enhanced, so that it is possible to achieve high-precision exposure of a large-sized panel. With the processing method according to the present invention, it is possible to stably obtain a large-sized photomask substrate with a high flatness, and since the CD accuracy (dimensional accuracy) at the time of exposure of the panel is enhanced, it is possible to perform exposure of a fine pattern, leading to a higher yield of the panel. Furthermore, by applying the processing method according to the present invention, it is also possible to create an arbitrary surface shape.

Large-sized substrate and method of producing the same

The present invention is to solve the problems caused by a conventional method for producing a zinc chloride-loaded support wherein zinc chloride is adsorbed on a solid support in an aqueous solution of zinc chloride. The problems include environmental destruction caused by the treatment of a used aqueous solution of zinc chloride, corrosion to a reactor, a threat to health for workers, deterioration of zinc chloride due to deliquescence thereof, and reduction of specific surface area.

Zinc chloride-loaded support and method for producing the same

A binder for hydraulic compositions comprises a water-soluble cellulose ether and a long-chain alkylbenzene-sulfonic acid or a neutralization salt thereof. The presence of the long-chain alkylbenzenesulfonic acid compound as a binder component provides hydraulic compositions with a better plasticity at a lower water-soluble cellulose ether content than when the cellulose ether is used alone as the binder.

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Joetsu, Japan

Masaki Tabata