Sanyo Chemical Industries, Ltd.

Kenjiro Tsubota

Keiji Tanaka

Masashi Date

Tsuyoshi Yuki

Satoshi Tamabuchi

Masanori Koike

Masahisa Fujita

An anti-bacterial water absorbing agent having excellent water absorption, anti-bacterial activity, and powder flow properties. The agent is useful in the manufacture of absorbent materials particularly for absorbing urine, blood, and body fluids and the like. The agent comprises a water absorbing resin (A) having pendant acid groups, at least on acid group being in the form of a quaternary ammonium salt having the general formula (1). ##STR1## wherein --X.sup.- is an anionic pendant group covalently bonded to backbone in the water absorbing resin (A) and R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are organic groups. In embodiments, at least one of the organic groups on the ammonium ion is an aliphatic alkyl group having 5 to 20 carbons. At least one of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is a C.sub.5 to C.sub.20 aliphatic alkyl group. The resin has a quaternary nitrogen atom content of about 2.times.10.sup.-4 % to about 0.8% by weight.

Anti-bacterial water absorbing agent and anti-bacterial water absorbent

A method for producing a water absorbent resin by polymerizing a water-soluble monomer having a polymerizable unsaturated group (A) and a crosslinking agent (B) as the essential components by radical polymerization in the presence of water or, polymerizing a water-soluble monomer having an unsaturated group (A) and a crosslinking agent (B) by radical-graft copolymerization with a water-soluble polymer (C) as the backbone polymer in the presence of water, wherein a water-based solid material capable of being endothermally fused or dissolved into water (D) is added when initiating the polymerization, with at least a part of the water-based solid material (D) in a solid state. By the method of the present invention, a water absorbent resin having a high molecular weight and a high absorption capacity with little water-soluble component can be obtained with ease.

Method for preparing water absorbent resin

A method for producing a water absorbent resin comprising the step of radically polymerizing a water-soluble radically polymerizable monomer having an acid group or a group of the salt thereof and optionally a polysaccharide in the presence of water using a crosslinking agent (C), wherein 0.0001 to 1 weight % of a thiol compound (D) having a radically polymerizable double bond, based on the above mentioned water-soluble radically polymerizable monomer (A), is used as the copolymerizing component to provide a water absorbent resin having a high absorbency and a good gel stability after absorbing body fluid, and a water absorbent comprising the water absorbent resin produced thereby.

Method for producing water absorbent resin and water absorbent

A method for preparing water-absorbent resins (D) by radically polymerizing a water soluble monomer (A), or a water-soluble monomer (A) and a polysaccharide (B) in the presence of a crosslinking agent (C) and water, wherein the polymerization is conducted under the existence of a thiol compound (E). Water-absorbent resins obtained in the method of the present invention provide high absorption while providing safety with very little amount of a water-soluble component.

Water-absorbing resin compositions obtained by adding a water-soluble thiol compound in the process of drying or pulverizing a hydrogel of a water-absorbing resin which is obtained by polymerizing a water-soluble monomer having a polymerizable unsaturated group optionally with a polysaccharide, in the presence of a crosslinking agent and water. Composition of the present invention are highly efficient in water absorption and safe for having extremely low amounts of residual monomer and water-soluble component.

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Kyoto-fu, Japan

Kenjiro Tsubota