Mitsubishi Petrochemical Company Limited

Mitsubishi Chemical Corporation

Unicharm Corporation

Kiichi Itoh

Takeshi Shibano

Yoshiaki Mori

Kenji Yoshinaga

Shuhei Yada

Shunichi Himori

Taisuke Ishii

Yasunari Sugyo

Kouji Katoh

Hiroyoshi Tsuchiya

Toshiko Nakamura

Shinji Tsunoi

Kohji Kato

Seiichiro Iida

Noriaki Fujitani

Masayuki Yamashita

Disclosed is a water-absorbent polymer composite and composition thereof comprising a water-absorbent polymer particle and two or more fibers, wherein said polymer particle has a substantially spherical shape, at least one of said two or more fibers is partially wrapped in the polymer particle and partially exposed to outside the particle, and at least one of said two or more fibers is unwrapped in the polymer particle and partially adhered to a surface of the polymer particle. This water-absorbent polymer composite is characterized in that the fibers are stably fixed to the water-absorbent polymer not only in dry but also in wet through water absorption for swelling, the water-absorbent polymer content can be enlarged relative to the fibers, the polymer can be uniformly fixed to the fibers, the composite is flexible and can be thinned, opened and mixed with any other material uniformly.

Water-absorbent polymer composite comprising two or more fibers, and composition thereof

Disclosed is a method for preparing a water-absorbent polymer composite comprising the steps of contacting a droplet containing a solvent and said polymerizable monomer before polymerization and/or under polymerization with first fibers fed through a first supply port of said reactor in a gas phase, proceeding with polymerization of said polymerizable monomer, contacting the resultant droplet containing said solvent, the polymerizable monomer under polymerization and said first fibers with second fibers fed through a second supply port of said reactor in a gas phase, and proceeding with further polymerization of said polymerizable monomer to form said water-absorbent polymer composite. The water-absorbent polymer composite prepared by the method is characterized in that the fibers are stably fixed to the water-absorbent polymer not only in dry but also in wet through water absorption for swelling, the water-absorbent polymer content can be enlarged relative to the fibers, the polymer can be uniformly fixed to the fibers, the composite is flexible and can be thinned, and it can be opened by itself and can be uniformly mixed with any other material.

Method for preparing water-absorbent polymer composite and accumulated material thereof

A polymerization method in which a first liquid and a second liquid are mixed in a gas phase and polymerized in the form of droplets is disclosed, wherein a polymerizable monomer and a polymerization initiator are each contained in at least one of the first liquid and the second liquid, and at least one of the first liquid and the second liquid is injected in a spatially expanding film shape. By employing the polymerization method of this invention, high-quality polymer can be efficiently produced in large quantity by the droplet polymerization even using a polymerizable monomer with a rapid reaction rate.

Method of polymerization and nozzle employed in same

This invention discloses a continuous production method of water-absorbing composite which comprises a complexation step for producing a particle-substrate composite by dropwisely supplying an aqueous solution of polymerizable monomers consisting mainly of an unsaturated carboxylic acid where 20% or more of the carboxyl groups in the unsaturated acid is neutralized, while allowing polymerization to proceed in the droplets, onto a fibrous substrate fed to the drop point to allow the incompletely polymerized polymer particles to adhere thereon, and by completing the polymerization thereafter; and a surface crosslinking step for reacting the composite with a crosslinking agent, having two or more functional groups capable of reacting with carboxyl group and/or carboxylate group, in the presence of 1 to 100 weight parts of water per 100 weight parts of polymer particles derived from the polymerizable monomer contained in the composite. Such continuous production method is successful in producing, in a continuous and efficient manner, a water-absorbing composite excellent in water absorption property and water retention property.

Continuous production method of water-absorbing composite

Water-absorbing composites, preparation processes thereof and water-absorbing articles

There is provided a water-absorptive composite comprising a fibrous substrate bearing water-absorptive polymer particles. A process for producing the water-absorptive composite comprises the steps of: allowing an aqueous monomer solution containing a polymerizable monomer capable of providing a water-absorptive polymer to initiate polymerization by the use of a redox polymerization initiator; applying the resultant reaction mixture, which is in the course of polymerization, dropwise onto a fibrous substrate; and allowing the polymerization to proceed and finish on the substrate.

Water-absorptive composite and process for producing the same

A method of preparing a water-soluble resin, which comprises the steps of: subjecting an aqueous solution of a first water-soluble ethylenically unsaturated monomer to a first-stage water-in-oil type of reverse-phase suspension polymerization using a water-soluble radical polymerization initiator in a hydrophobic organic solvent in the presence of an emulsifier and optionally a crosslinking agent, thereby forming a slurry containing hydrous polymer gel particles; adding to said slurry a nonionic or anionic surface active agent having an HLB of at least 7 and higher than that of said emulsifier and an aqueous solution of a second water-soluble ethylenically unsaturated monomer so as to absorb the aqueous solution of the second monomer in said hydrous polymer gel particles; and carrying out a second-stage polymerization of said second monomer.

Method of preparing water-absorbing resin

A process for producing a highly water absorptive polymer by polymerizing a water-soluble, ethylenically unsaturated monomer in a water-in-oil type of dispersion consisting of the dispersion phase of an aqueous monomer solution comprising the water-soluble, ethylenically unsaturated monomer, water, a water-soluble polymerization initiator and an optional water-soluble crosslinking agent and the continuous phase of an organic solvent containing a dispersant, characterized in that the aqueous monomer solution is added to the organic solvent at such a temperature as to form an oil-in-water type of dispersion, and the oil-in-water type of dispersion is then heated at least to a phase reversal temperature at which it is transformed into the water-in-oil type of dispersion.

Process for the production of highly water absorptive polymers

There is provided a process for producing a substantially water-insoluble, highly water-absorptive polymer which comprises subjecting an aqueous solution of a monomer comprising as a main component acrylic acid and/or its alkali metal salt to polymerization in the presence of a hypophosphorous acid compound.

Process for producing highly water-absortive polymers

There is provided a process for producing a highly water absorptive polymer, which comprises making up a mixture (A) comprising an aqueous solution of (a) a partially neutralized product of acrylic acid with 20% or more of carboxylic groups being neutralized to an alkali metal salt or ammonium salt, (b) a crosslinking agent having two or more copolymerizable vinyl groups in one molecule, (c) a basic vinyl monomer in a quantity of 20 mol % or less based on said partially neutralized product of acrylic acid, (d) a nonionic surfactant with HLB of 7 or more and (e) an oxidative radical polymerization initiator, said mixture (A) being maintained at a temperature of 50.degree. C. or lower, and a mixture (B) comprising an amine or a reducing agent dissolved in water or in said mixture (A) from which at least the component (e) is removed, and mixing both the mixtures to cause polymerization.

Process for producing highly water absorptive polymer

A water penetration preventive cable comprising an assembly of linear elements comprising a core wire in various forms and an optional linear tensile strength element, the assembly being covered with a sheath, characterized in that the linear elements and/or the sheath are wound with a water absorptive tape, and/or in that the gap between the linear elements and/or between the linear element and the sheath is filled with a linear water absorptive linear elements, wherein the water absorptive tape and water absorptive linear elements are made of a water absorptive polymer supported on a tape-like or linear support.

Water penetration preventive cable

A process for the preparation of water absorptive resins which comprises supplying a solution containing at least 20% by weight of a water soluble ethylenically unsaturated monomer as a main component to a polymerization vessel accommodating a vapor phase comprising steam or a mixture of steam with at least one gas substantially inert with respect to polymerization, and polymerizing the monomer in the vapor phase under the relative humidity conditions in the vapor phase of 30% or more.

Process for the preparation of water absorptive resin

A process for producing a highly water adsorptive polymer, which comprises subjecting an aqueous solution of partially neutralized sodium acrylate wherein 20 to 50% or less of the carboxyl group has been neutralized to its sodium salt, the concentration of the partially neutralized sodium acrylate in the aqueous solution being 45 to 80% by weight, to solution polymerization in the presence of a crosslinking agent and optionally not exceeding 20 mol % based on the partially neutralized sodium acrylate of at least one basic vinyl monomer selected from the group consisting of (meth)acrylamide, N,N-dimethyl(meth)acrylamide, dimethylaminoethyl(meth)acrylamide, 2-vinylpyridine, and 4-vinylpyridine with the use of a water soluble radical polymerization initiator.

There is provided a process for preparing a water absorptive composite, which comprises the combination of the steps of (A) applying an aqueous solution containing (a) a polymerizable monomer comprising as a main component acrylic acid, of which 20% or more of the carboxyl groups have been neutralized to its alkali metal salt or ammonium salt, (b) a crosslinking agent, (c) a polyoxyethylene acyl ester with HLB of 7 or more and (d) an oxidative radical polymerization initiator to a prefabricated fibrous substrate and (B) polymerizing the polymerizable monomer applied to the fibrous substrate with addition of a reducing agent to form a composite of a polymer derived from the polymerizable monomer and the fibrous substrate.

Process for preparation of water absorptive composite

There is provided a process for preparing a water absorptive composite material, which comprises the combination of the following steps:

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Yokkaichi, Japan

Kiichi Itoh