Kuraray Co., Ltd.

Yamaguchi University

Atsushi Jikihara

Naoki Fujiwara

Kenichi Kobayashi

Mitsuru Higa

Toshiaki Sato

Masato Nakamae

Takeshi Kusudou

Misa Watanabe

Takahiro Nakashima

Takashi Wakui

Toshiyuki Akasawa

Sadahiko Shiraga

Somemiya Kazuyuki

Naoki Fujuwara

Koji Hori

Kazuki Nakagawa

Provided is an ion exchange membrane including an ionic vinyl alcohol polymer having a cation exchange group or an anion exchange group. The ion exchange membraneincludes a porous supportand the ionic vinyl alcohol polymer. The porous support is provided, in a thickness direction from one surface thereof, with an impregnated layerat least a part of which is impregnated with the ionic vinyl alcohol polymer. The ionic vinyl alcohol polymer includes an ionic vinyl alcohol polymer having an ion exchange group selected from a cation exchange group or an anion exchange group. The ion exchange membrane has a zeta potential value (&#x3b6;1) at one surface and a zeta potential value (&#x3b6;2) at the other surface, which are represented by the formula (1).(|&#x3b6;1|)&#x2212;|&#x3b6;2|)/|&#x3b6;1|&#x3c;0.5 (|&#x3b6;1|)&#x2265;|&#x3b6;2|)&#x2003;&#x2003;(1)

Ion exchange membrane, method for producing same, and electrodialyzer

Provided is a cation exchange membrane having a stable ion exchange performance during usage, being excellent in basic properties such as membrane resistance and ion transportation as well as strength, and useful for electrodialysis and a method for producing the same. The cation exchange membrane is composed of a polyvinyl alcohol copolymer including an anionic group-containing anionic polymer segment and a vinyl alcohol polymer segment, and having a microphase separation structure having a domain size (X) in a range from 0 nm&#x3c;X&#x2266;150 nm. The method is composed of forming a membrane from a polyvinyl alcohol copolymer which is adjusted to contain salts in a proportion that the salt weight (C) relative to the polyvinyl alcohol copolymer weight (P) is [(C)/(P)] of 4.5/95.5 or lower.

Cation exchange membrane and method for producing same

There is provided a multilayered charge-mosaic membrane having a porous supporting layer (A), a porous intermediate layer (B) and a charge-mosaic layer (C), wherein the porous supporting layer (A), the porous intermediate layer (B) and the charge-mosaic layer (C) are located in this order; the porous supporting layer (A) and/or the porous intermediate layer (B) are made of a fiber layer containing hydrophilic fibers; a thickness of the porous intermediate layer (B) is 0.1 to 100 &#x3bc;m; a porosity of the porous supporting layer (A) is larger than a porosity of the porous intermediate layer (B); the cationic and/or the anionic polymers constituting the charge-mosaic layer (C) is a polyvinyl alcohol having an ionic group. Thus, there is provided a multilayered charge-mosaic membrane having a large salt permeation flux and excellent mechanical strength.

Multilayered charge-mosaic membrane and manufacturing method therefor

There is provided an anion exchange membrane comprising, as a main element, a block copolymer having a vinyl alcohol polymer block and a cationic-group containing polymer block as components and which is subjected to a crosslinking treatment. An anion exchange membrane is produced by heating a film obtained from a solution of the block copolymer at a temperature of 100&#xb0; C. or more, crosslinking the film with a dialdehyde compound in water, an alcohol or a mixture of these under an acidic condition and then washing the film with water. Thus, there can be provided an anion exchange membrane in which organic fouling can be prevented and which exhibiting excellent basic properties such as a membrane resistance and an ionic transport number and excellent membrane strength.

Anion exchange membrane and method for producing same

There is provided an ion-exchange membrane comprising an ion-exchange layer made of a cationic polymer and/or an anionic polymer and a supporting layer, wherein the ion-exchange layer is formed on the supporting layer by printing. Such an ion-exchange membrane exhibits excellent anti-organic fouling and low membrane resistance, thereby high efficient and long-time stable electrodialysis can be achieved. Formation of the ion-exchange layer as a charge-mosaic layer consisting of the cationic polymer domains and the anionic polymer domains provides a charge-mosaic membrane exhibiting excellent electrolyte permselectivity and mechanical strength.

Ion-exchange membrane and method for producing same

In the present invention, a dispersion that has excellent dispersion efficiency, shows hardly any premature graying, and exhibits excellent dispersion stability and storage stability when heated is prepared, and the thermal recording material excellent in color developing sensitivity and whiteness of the background is provided. The present invention provides a thermal recording material including a support and a thermosensitive coloring layer that is provided on the support and contains an electron-donating colorless dye and an electron-accepting compound, wherein the thermosensitive coloring layer contains a polyvinyl alcohol-based resin (A) containing a carboxyl group that has been produced by saponification of polyvinyl ester obtained by the polymerization in the presence of aldehydes or ketones and that has an absorbance at 280 nm of 0.20 to 0.85 obtained from an ultraviolet absorption spectrum of a 0.1 wt % aqueous solution thereof.

Thermal recording material

A vinyl alcohol polymer is provided that is particularly useful for efficiently producing an inkjet recording material having an ink-receiving layer which is not cracked on its surface, which is highly glossy, which can absorb ink well and which is highly transparent, wherein the vinyl alcohol polymer has specific polyoxyalkylene group-containing monomer units and where the product of the viscosity-average degree of polymerization, P, of the vinyl alcohol polymer and the content, S (mol %), of polyoxyalkylene group-containing monomer units, P&#xd7;S, and the number, n, of the oxyalkylene repeating units in the polyoxyalkylene group-containing monomer unit satisfy specific relational formulae.

Vinyl alcohol polymer

A polyvinyl alcohol having hydrolyzed silyl group functionalized monomer units. The polyvinyl alcohol satisfies the following formulae (I) and (II) and the pH of an aqueous 4% solution of the polyvinyl alcohol is between 4 and 8:20&#x3c;&#x2003;&#x2003;(I) wherein P is the viscosity-average degree of polymerization of the polyvinyl alcohol, and S is the content of the silyl group functionalized monomer units in the polyvinyl alcohol,0.1/100&#x2266;()/()&#x2266;50/100&#x2003;&#x2003;(II) wherein A is the silicon atom content of the polyvinyl alcohol, B is the silicon atom content of the polyvinyl alcohol that has been washed with sodium hydroxide-containing methanol and then washed through Soxhlet extraction with methanol. The polyvinyl alcohol may be readily dissolved in water in the absence of sodium hydroxide or an acid; the aqueous solution has good viscosity stability; the binding force with inorganic substances is high; and a film formed of its mixture with an inorganic substance is excellent in resistance to water. The polyvinyl alcohol is favorable for coating agents for inkjet recording materials and thermal recording materials.

Vinyl alcohol polymer and process for producing vinyl alcohol polymer

Provided are a water resistant composition comprising a uniform mixture of (A) at least one of modified polyvinyl alcohol containing either from 1 to 20 mol % of &agr;-olefin units with not more than 4 carbon atoms, from 0.01 to 1 mol % of silyl groups, or from 1 to 20 mol % of &agr;-olefin units with not more than 4 carbon atoms and from 0.01 to 1 mol % of silyl groups and (B) an organotitanium compound having a chelating ligand, in a blend ratio of component (A) to the component (B) between 99.99/0.01 and 60/40 by weight; a coating agent comprising the composition; a thermal recording material having a coat layer of the composition; and an ink-jet recording material having an ink-absorbing layer of the composition.

Water resistant composition, coating agent, and recording material

According to the present invention, there are provided a process for producing a vinyl alcohol polymer comprising reaction of a vinyl ester polymer (A) having an epoxy group with a compound (B) having a thiol or thioester group and hydrolysis thereof, said hydrolysis being conducted during or after said reaction; and a process for producing a vinyl alcohol polymer comprising reaction of a vinyl ester polymer (C) having a thiol or thioester group with a compound (D) having an epoxy group and hydrolysis thereof, said hydrolysis being conducted during or after said reaction. According to the present invention, it is possible to efficiently introduce into PVA various functional groups having excellent reactivity, crosslinkability, ionic interactivity, water-solubility, interfacial physical properties, low-temperature flexibility, etc., under relatively mild reaction conditions. According to the present invention, in addition, it is possible to introduce into PVA such various functional groups, which could not be obtained by conventional methods.

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Kurashiki, Japan

Atsushi Jikihara