Nippon Shokubai Co., Ltd.

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Kunihiko Ishizaki

Kozo Nogi

Shinichi Fujino

Satoshi Matsumoto

Yorimichi Dairoku

Yoshio Irie

Katsuyuki Wada

Nobuyuki Harada

Katsuhiro Kajikawa

Takumi Hatsuda

Hirotama Fujimaru

Kinya Nagasuna

Shigeru Sakamoto

Sumio Okuda

Syuji Kanzaki

Kazuki Kimura

Masatoshi Nakamura

Shin-Ichi Fujino

Yoshihiro Motono

Koji Matsumoto

Kazushi Torii

Koji Miyake

Teruyuki Kanto

Sei Nakahara

Yasuhiro Fujita

Yoshifumi Adachi

Motohiro Imura

Yusuke Watanabe

Ryota Wakabayashi

Reiko Nakatsuru

Kazuhisa Hitomi

Koji Honda

Takashi Azumi

Yukihiro Matsumoto

Hiroyuki Ikeuchi

Sayaka Machida

Yoshihiko Masuda

Hiroko Ueda

Toshimasa Kitayama

Yasuhisa Nakashima

Takahiro Kitano

Makoto Nagasawa

Kazumasa Konishi

Yoshihiro Shobo

Mai Sato

Shin-ya Katsube

Soichi Yamada

Hisanobu Obara

Kazuhiko Sakamoto

Tadao Shimomura

Yoshiro Mitsukami

Hirofumi Shibata

Tokio Shuto

Toru Nishioka

Hiroyasu Watabe

Yuki Kabeya

Kenji Kadonaga

Kazumasa Kimura

Hiroki Inoue

Yoshitake Ishii

Teruaki Fujiwara

Takeshi Takayama

Akito Yano

Toyofumi Sakai

Takaaki Kawano

Toru Yanase

Naoko Takahashi

Tsuyoshi Yorino

Takashi Miyamoto

Yoko Shirai

Tomoyuki Arake

Noriaki Mizutani

Masafumi Inoue

Sachie Kitabata

Atsushi Motoyama

Hiroki Hayashi

Naoki Katakura

Yoshiki Katada

Takanori Murakami

Kaoru Iwasaki

Sumito Kumagai

Eri Nagasawa

Teruhisa Nagashima

Eri Goto

Kanako Tsuru

Takashi Nishigaki

Jiro Sano

Sachio Fujita

Yoshiniko Masuda

Shin-ichi Fujino

Provided is an additive for concrete in which viscosity of a cement composition is low and fluidity is high at an initial stage of casting even when the additive is added, and long-term strength of concrete or the like improves by the addition. A cement additive comprising a water-absorbent resin, wherein the water-absorbent resin is formed by polymerizing a monomer mixture containing no less than 50 mol % of a nonionic non-crosslinkable monomer and no less than 0.1 mol % of a nonionic crosslinkable monomer, and a content of an anionic monomer in the monomer mixture is no more than 20 mol %.

Cement additive, cement admixture, cement composition, molded body, and method for improving strength of molded body

A production method includes a surface-crosslinking step of heating a mixture of a surface-crosslinking agent and a particulate dried polymer obtained with an acid group-containing unsaturated monomer as a main component. A moisture content of the particulate dried polymer is not greater than 15% by mass. A heating device including a rotary container and a plurality of heating tubes that are located within the rotary container, extend in an axial direction of the rotary container, and rotate together with the rotary container, is used in the surface-crosslinking step. The heating device includes a means for introducing and discharging a gas into and from the rotary container.

Method for producing water-absorbent resin particles

The present invention addresses the problem of reducing the undried residue when recycling a fine powder of water-absorbing resin. The present invention is a method for producing a water-absorbing resin, wherein: a fine powder recycling step includes vi-1) a granulation step for obtaining a granulated gel, vi-2) a granulated gel addition step, and vi-3) a gel mixing step; the solids content of the granulated gel in the granulated gel addition step is 50-90% by mass; and the temperature of the granulated gel and the temperature of the water-containing gel-like crosslinked polymer is 50-100° C.

Method for producing water-absorbent resin

An object of the present invention is to provide a water absorbent resin powder for a heat-generating element composition, which suppresses the generation of the aggregates derived from the water absorbent resin and the adhesion of the water absorbent resin in the production of a heat-generating element composition. A present inventive water absorbent resin powder for a heat-generating element composition includes polyacrylic acid (salt)-based water absorbent resin powder which have a bulk specific gravity (specified by JIS K3362) of 0.630 g/cmor less, fluid retention capacity without load (CRC) for a 0.9% by weight aqueous solution of sodium chloride (specified by ERT441.01-2) of 32.0 g/g or less, a weight-average particle diameter (specified by sieve classification) of 250 μm or more, and an amount of a residual glycidyl-based crosslinking agent of 10 ppm or less.

Water absorbent resin powder for heat-generating element composition, and heat-generating element composition

The production method includes a drying step of drying a particulate crosslinked hydrogel polymer obtained by polymerizing a monomer, which is a material of a water-absorbent resin, using a heating device to obtain dried particles. The heating device includes: a rotary container that contains the particulate crosslinked hydrogel polymer therein and rotates; and a plurality of heating tubes that are located within the rotary container, extend in an axial direction of the rotary container, and rotate together with the rotary container. A gel temperature of the particulate crosslinked hydrogel polymer to be subjected to the drying step, the gel temperature being measured by a contact thermometer, is not lower than 50&#xb0; C.

Method for producing water-absorbent resin powder, and drying device and drying method for particulate hydrous gel

The production method includes: a gel-crushing step of grinding a crosslinked hydrogel polymer to obtain a particulate crosslinked hydrogel polymer; a heating drying step of obtaining dried particles from the particulate crosslinked hydrogel polymer by using a continuous stirring drying machine; a post-crosslinking step of post-crosslinking the particulate crosslinked hydrogel polymer or the dried particles; and a sizing step of adjusting a particle size of the dried particles or the post-crosslinked dried particles to obtain water-absorbent resin powder. The particulate crosslinked hydrogel polymer contains a gel fluidizer. A gel temperature of the particulate crosslinked hydrogel polymer containing the gel fluidizer, the gel temperature being measured by a contact thermometer, is not lower than 50&#xb0; C. In the production method, the dried particles or the post-crosslinked dried particles is forcedly cooled before the sizing step.

Method for producing water-absorbent resin powder and production apparatus therefor

A polyacrylic acid (salt), or a polyacrylic acid (salt)-based water-absorbing resin, contains a tracer for detecting various troubles in the water-absorbing resin during the period from the production of the water-absorbing resin to the use and discard thereof by a consumer. The polyacrylic acid (salt)-based water-absorbing resin has a stable carbon isotope ratio, as determined by accelerator mass spectrometry, of less than &#x2212;20&#x2030; and a radioactive carbon content of 1.0&#xd7;10or more. The polyacrylic acid (salt)-based water-absorbing resin has: a CRC of 10 [g/g] or more; an AAP of 20 [g/g] or more; an Ext of 35 wt. % or less; a content of residual monomers of 1,000 ppm or less; a PSD in which the proportion of particles having a particle diameter of 150 &#x3bc;m or larger but less than 850 &#x3bc;m is 90 wt. % or more; and an FSR of 0.15 [g/g/s] or more.

Polyacrylic acid (salt), polyacrylic acid (salt)-based water-absorbing resin, and process for producing same

Disclosed are a polyacrylate (salt) and a polyacrylate (salt) water-absorbent resin containing a tracer which can be verified back to the manufacturing process of the water-absorbent resin when dealing with various problems with the water-absorbent resin which can occur from the manufacturing process of the water-resistant resin, during the use thereof by a consumer, up until the disposal thereof. The disclosed polyacrylate (salt) and the polyacrylate (salt) water-absorbent resin have a carbon stable isotope ratio (&#x3b4;C) of at least &#x2212;20&#x2030; when measured by accelerator mass spectrometry.

Provided is a method for producing a particulate water absorbing agent, the method including the steps of: a polymerization step of polymerizing an acrylic acid (salt)-based aqueous monomer solution so as to obtain a crosslinked hydrogel polymer; a drying step of drying the crosslinked hydrogel polymer so as to obtain a dried polymer; a classification step of classifying a polymer subjected to classification so as to obtain a water-absorbing resin powder having a specific particle size; and a surface-crosslinking step of surface-crosslinking the water-absorbing resin powder that is not surface crosslinked, wherein the classification step is carried out at least either or both of before and/or after the surface-crosslinking step but after said drying step, and wherein a hole shape of a classification sieve used in the classification step is an irregular polygonal or non-circular.

Method for producing particulate water-absorbing agent

From a view pint of decreasing an out of spec product after surface crosslinking, particularly, when an alkylene carbonate compound is used as a surface crosslinking agent, influence due to an air temperature is great, and it is necessary to reduce ethylene glycol which is produced as a byproduct. There is provided a process for producing a polyacrylic acid (salt)-based water absorbent resin powder, comprising storing a non-polymerized organic compound being a raw material (modified raw material) of a water absorbent resin powder in a heated state, thereafter, mixing the non-polymerized organic compound with other compound at a predetermined ratio and, further, mixing the mixture into a water absorbent resin powder.

Method for producing polyacrylic acid (salt)-based water absorbent resin powder

A method according to the present invention for producing water absorbent resin powder is a method for producing water absorbent resin having a surface cross-linked structure, and includes: a polymerization step in which an unsaturated monomer aqueous solution is polymerized; a drying step in which a hydrogel cross-linked polymer obtained in the polymerization step is dried; a surface treatment step in which the hydrogel cross-linked polymer or a dried hydrogel cross-linked polymer is subjected to a surface treatment; and a sorting step, carried out after the drying step, in which a foreign matter included in a water absorbent resin is color-sorted from the water absorbent resin entirely or partially. As a result, it is possible to obtain a water absorbent resin which has high properties and is less likely to be colored. In this way, there is provided the water absorbent resin powder production method in which the color sorting technique is used to remove foreign matters from the water absorbent resin.

Package of water absorbent resin powder

The disclosed process for continuously producing a water-absorbing resin comprising a plurality of joined continuous steps; a polymerization step of polymerizing an aqueous unsaturated monomer solution, a drying step of drying a particulated water-containing gel-like crosslinked polymer obtained in a finely crushing step during the polymerization or after the polymerization, a pulverizing step after the drying, a classification step after the drying, and a surface treatment step for the water-absorbing resin powder after the classification step. In the process, with some of the above steps kept running, the other steps are interrupted, and subsequently all the steps are restarted.

Process for producing water-absorbing resin

Production method of water absorbent resin powder and package of water absorbent resin powder

A method for producing a polyacrylic acid (salt)-based water absorbent resin, sequentially including the steps of: storing or producing acrylic acid; mixing acrylic acid containing a polymerization inhibitor with water, a crosslinking agent, and optionally, a basic composition, and/or neutralizing them, to prepare an aqueous monomer solution; polymerizing the aqueous monomer solution; drying an obtained water-containing gel-like crosslinked polymer; and optionally carrying out surface crosslinking, wherein the acrylic acid containing the polymerization inhibitor has a water content of not higher than 1,000 ppm (by mass; the same applies hereinafter), and/or the aqueous monomer solution has a formic acid content of 1 to 700 ppm, relative to the monomer.

Polyacrylic acid (salt)-based water absorbent resin and method for producing same

Provided is a process for producing a water-absorbing resin powder which contains a given amount of water added thereto, has a low dust content, and has high material properties. When a water-absorbing resin powder which has undergone surface crosslinking is produced on an industrial scale, various problems concerning production are eliminated and a long-term stable operation is possible without causing a deterioration in the material properties of the resin. Even when the process is continued over a long period, the material properties are stabilized (decrease in standard deviation) or improved (improvement in AAP). The process for producing a water-absorbing resin comprises, in the following order, a first classification step for classifying a water-absorbing resin, a surface crosslinking step after the classification, a water addition step for adding water to the water-absorbing resin powder after or during the surface crosslinking, a second classification step, and a conveying step.

Process for producing water-absorbing resin powder

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Suita, Japan

Kunihiko Ishizaki