Nippon Shokubai Co., Ltd.

Other

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Nippon Shokubai Kagaku, Co., Ltd.

Masazumi Sasabe

Kenji Kadonaga

Kozo Nogi

Katsuhiko Sakamoto

Hirotama Fujimaru

Akiko Mitsuhashi

Kazutomo Takahashi

Yorimichi Dairoku

Shigeru Sakamoto

Kenji Tada

Teruaki Fujiwara

Masuji Izubayashi

Seiji Kato

Yoshio Irie

Hiroshi Yamazaki

Kinya Nagasuna

Motohiro Imura

Kenji Minami

Koichi Yonemura

Motohiro Arakawa

Shobu Shioji

Koji Miyake

Yasuhiro Fujita

Yoshifumi Adachi

Masatoshi Yoshida

Hiroki Inoue

Yoshihiko Masuda

Hiroko Ueda

Sumio Okuda

Keiichiro Mizuta

Tsunemasa Ueno

Akihiko Fukada

Atsushi Tachibana

Shigeru Oka

Kaoru Iwasaki

Shuji Kanzaki

Hiroaki Hattori

Akihiro Morita

Yoshihiro Kita

Shigeyasu Morihiro

The present invention is a method for producing a water absorbent resin which method is a method for producing surface cross-linked water absorbent resin particles, the method including the successive steps of: (a) adding a surface cross-linking agent and water to a particulate water absorbent resin in a mixer; and (b) reacting the resulting water absorbent resin mixture taken out from the mixer with the surface cross-linking agent in a reactor by heating or active energy ray irradiation, water vapor being used as part or all of the water added in the mixer. This makes it possible to provide a method for producing a water absorbent resin in which method a surface cross-linked water absorbent resin that has excellent properties can be obtained efficiently at low cost with high productivity.

Method for producing water absorbent resin

Aqueous liquid and moisture vapor are added to water absorbent resin powder so that particles of the water absorbent resin powder are bound. Supplying the aqueous liquid and moisture vapor to the water absorbent resin powder reduces the amount of particles that remain unbound (ungranulated) and increases the concentration of the water absorbent resin bound particles to provide improved drying efficiency and to obtain particulate water absorbent resin having excellent properties even when the bound particles are highly concentrated. The present invention provides (i) a method for binding water absorbent resin and (ii) a method for producing particulate water absorbent resin including the step of binding particles of water absorbent resin powder.

Binding method of water absorbent resin

An object of the present invention is to provide a waste solution solidifying agent which can solidify a waste solution, particularly, a waste solution containing blood or body fluid at a low cost, uniformly, and in a short time; in particular, to provide a waste solution solidifying agent which can solidify a waste solution uniformly and in a short time in a vertically oriented waste solution equipment. As a means of achieving this object, a waste solution solidifying agent of the present invention is a particulate treating agent used in a method of treating a waste solution which solidifies a waste solution into a gel by placing a treating agent in a waste solution, and is characterized in that said agent contains, as an essential component, a water-absorbent resin having a crosslinked structure obtained by polymerizing a water-soluble ethylenic unsaturated monomer and, when flowing-placed at once into a 0.90 mass % aqueous sodium chloride solution, 20 to 95 mass % of the agent is floated, and 80 to 5 mass % is settled. And a process for preparing a waste solution solidifying agent of the present invention is a process for preparing a particulate waste solution solidifying agent containing, as an essential component, a water-absorbent resin having a crosslinked structure obtained by polymerizing a water-soluble ethylenic unsaturated monomer, and comprises a step of mixing a hydrophobic substance having a methanol index of 20 or more after polymerization.

Waste solution solidifying agent, process for preparing the same and use of the same

A production method of a water-absorbent resin includes the steps of: obtaining a hydrogel by supplying monomer liquid to a reaction device so that the monomer liquid is polymerized; and detaching the hydrogel from the reaction device, wherein the reaction device's surface in contact with the monomer liquid at a position where polymerization occurs is made of a fluororesin having a melt viscosity of less than 1&#xd7;10poise at 380&#xb0; C. On this account, it is possible to obtain a water-absorbent resin having less amounts of an extractable content with high productivity and it is possible to carry out continuous production for an extended period of time.

Production method of water-absorbent resin

A homogeneously surface cross-linked water absorbent resin and a method for the production thereof are provided. The water absorbent material is formed of a surface cross-linked water absorbent resin resulting from granular irregularly pulverized shaped surface cross-linking the product of partial neutralization or whole neutralization of a water absorbent resin having acrylic acid or a metal salt thereof as a main component, which water absorbent material shows a metal atom concentration on the surface of the water absorbent material in the range of 0-10% within 0 second of polishing and 2-35% at 10 seconds value of polishing as determined by subjecting the water absorbent material to Ar ion discharge polishing under a voltage of 500 &#x212b;. The surface cross-linked water absorbent resin to be used herein can be produced by surface cross-linking a water absorbent resin having a specific particle diameter with a surface cross-linking agent having a water concentration in a specific range.

Water absorbent material, method for production of surface cross-linked water absorbent resin, and method for evaluation of water absorbent material

An object of the present invention is to make it possible that: a high-concentration hydrogel sheet, which is suitable for production of high-performance water-absorbent resin particles, is cut efficiently without involving the adhesion to such as cutting-blades; and the subsequent disintegration operation is also successfully carried out; and hydrogel particles excellent in the quality and performances are efficiently produced. As a means of achieving this object, the process according to the present invention for production of hydrogel particles is a process for production of the hydrogel particlesfrom a high-concentration hydrogel sheetand comprises: a step (a) of cutting a continuous sheetof a crosslinked high-concentration hydrogel polymer of 50 to 80 weight % in solid component concentration every 10 to 100 cm lengthwise of the continuous sheetwhile running it lengthwise, thereby obtaining cut pieces; and a step (b) of continuously supplying the cut pieces(obtained from the step (a)) to a continuous disintegratorto continuously carry out disintegration and discharge under conditions where the supply amount of the cut piecesand the disintegrating and discharging abilities of the continuous disintegratorsatisfy (supply amount)&#x2266;(disintegrating and discharging abilities), thereby obtaining the hydrogel particles

Process for production of hydrogel particles and process for cutting of high-concentration hydrogel sheet

A method for mixing a water-absorbent resin and a surface cross-linking agent-containing solution to repress aggregates is equipped. The water-absorbent resin and the surface cross-linking agent-containing solution is mixed with a plow-shaped mixing device which is equipped with an inner wall formed of material manifesting an interfacial contact angle of not less than 60&#xb0; to water and possessing a temperature of heat distortion of not lower than 70&#xb0; C., a plow-shaped stirring vane and a disintegrating blade.

Method for production of water-absorbent resin and plow-shaped mixing device

A method directed to manufacturing porous products by supplying a water-in-oil type high internal phase emulsion into mold elements, shaping and polymerizing the emulsion. It is characterized by a moving shaping unit provided with a lower mold element on one side having a smooth mold face furnished with a depressed part and an upper mold element on the other side having a smooth mold face furnished with a corresponding depressed part forming a cavity of a stereoscopic shape together with the depressed part of the lower mold element. Prior to the union of the two mold elements continuously supplying the emulsion into the two mold elements, transferring the shaping unit into a polymerizing device subsequent to the union of the mold elements, and shaping and polymerizing the emulsion therein.

Method for manufacture of porous product from molded high internal phase emulsion

A method for dehydrating a porous cross-linked polymer conveniently to a low final water content is provided. A porous cross-linked polymer sheet is produced by a method which comprises causing a porous cross-linked polymer obtained by forming and polymerizing a water-in-oil type higher internal phase emulsion to be dehydrated by the use of non-woven fabric rolls furnished with an aspiration mechanism. Properly in this case, the porous cross-linked polymer is subjected to preliminary squeezing. In accordance with the present invention, a porous cross-linked polymer abounding in a water absorbing property to be dehydrated to a low final water content with a small number of rolls.

Method for production of porous cross-linked polymer sheet

Method for production of porous cross-linked polymer

A method for the production of a porous cross-linked polymer material by the polymerization of an HIPE containing a cross-linking agent, characterized by the fact at least one species of the cross-linking agent is a compound having a double bond equivalent f not less than 120 g/mol. The cross-linking agent is preferred to be a compound possessed of an alkylene oxide moiety or a vinyl polymer containing not less than two polymerizing double bonds in the molecular unit. Thus, it is made possible to produce a porous cross-linked polymer material excellent in absorbency and flexibility, permit the HIPE to be polymerized in a short time, and therefore improve the efficiency of production.

Method for production of porous cross-linked polymer material

A method for producing a porous cross-linked polymer sheet capable of slicing quickly is provided. This method comprises a step for obtaining a porous cross-linked polymer by forming and polymerizing an HIPE, a step for dehydrating the porous cross-linked polymer, and a step for subsequently slicing the dehydrated porous cross-linked polymer. According to this invention, by performing the step of dehydration prior to the conventional step of slicing, it is made possible to prevent the porous cross-linked polymer from adhering to the blade and the guides provided for a slicer, and allow the slicing to be attained quickly. By removing the salt from the polymer, it is further made possible to prevent a production device from gathering rust and the porous cross-linked polymer from permitting adhesion of rust thereto.

Method of manufacturing porous cross-linked polymer sheet

An object of this invention is to provide a method for the production of a porous cross-linked polymer, which permits the polymerization (curing) of a water in oil type high internal phase emulsion (HIPE) in such an exceptionally brief time as not more than 30 minutes, preferably not more than 10 minutes without impairing the stability of the HIPE. The object of this invention mentioned above can be accomplished by a method for the production of a porous cross-linked polymer which comprises steps of mixing an oil phase containing a polymerizing monomer, a cross-linking monomer, and a surfactant as essential components with a water phase containing water as an essential component thereby obtaining a water in oil type high internal phase emulsion and heating said emulsion to a prescribed curing temperature thereby polymerizing the emulsion, wherein said emulsion is formed in a thickness of not more than 50 mm and the temperature-increasing rate of the emulsion is not less than 5&deg; C./minute.

Method for production of porous cross-linked poymer

An object of this invention is to provide a method for the production of a porous material by polymerizing a water-in-oil type high internal phase emulsion in a briefer time than a conventional technique without impairing the stability of the emulsion. The object of this invention can be accomplished by a method for the production of a porous material comprising a step of polymerizing a water-in-oil type high internal phase emulsion containing a polymerization initiator, wherein the polymerization initiator is a redox type initiator combining a water-soluble oxidizing agent and a reducing agent, the reducing agent is preparatorily added to form the emulsion, and thereafter the water-soluble oxidizing agent is added to the emulsion to polymerize the added emulsion.

Method for production of porous material

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Kakogawa, Japan

Masazumi Sasabe