Nippon Shokubai Co., Ltd.

Other

Nobuhiro Kobayashi

Masatoshi Yoshida

Hiroaki Hasegawa

Akio Ito

Toshiya Takagi

Toshiya Iida

Atsushi Okada

Toshimi Aoyama

Satoshi Ishida

Takako Ishii

Koji Kahara

A method of producing a copolymer of the present invention is a method of producing a specific copolymer and includes: a pure water production step of producing pure water having an electric conductivity of from 0.1 &#x3bc;S/cm to 100 &#x3bc;S/cm; a pure water transfer step of introducing the pure water into a reaction kettle for producing the copolymer through a transfer pipe using, as a material therefor, a resin or a substance forming a passive state in water; and a polymerization step of performing polymerization of the monomer (a), the monomer (b), and the monomer (c) in the reaction kettle, the pure water transfer step including setting the electric conductivity of the pure water at a site where the pure water is introduced from the transfer pipe toward the reaction kettle within a range of from 0.1 &#x3bc;S/cm to 100 &#x3bc;S/cm.

Method for producing copolymer

A borate for a near-infrared ray absorption material, having an anion represented by the formula (1): [BRR](wherein Rrepresents an aryl group having an electron withdrawing group; Rrepresents an organic group, a halogen group or a hydroxyl group; and m is an integer in the range of 1 to 4) is provided. The borate of the present invention enables to improve durability, in particular, heat resistance and moisture resistance of a near-infrared ray absorbing dye.

Borate and near-infrared ray absorption material

The present invention provides a new star-shaped block copolymer and a production process therefor, wherein the new star-shaped block copolymer has high heat resistance despite having a low viscosity. It has been found that a new star-shaped block copolymer has high heat resistance wherein the new star-shaped block copolymer comprises a plurality of star-shaped structures,in which at least three chain polymer segments,are radially extended from a central polyvalent mercaptan segment,, wherein the star-shaped structures,are bonded to each other through a bonding structure,at their chain polymer segments. In addition, in a production process for a star-shaped block copolymer comprising the multistep radical polymerization in the presence of a polyvalent mercaptan wherein the elementary steps of the multistep radical polymerization differ in polymerizable monomers as used therein, the improvement according to the present invention is characterized in that at least one of the elementary steps of the multistep radical polymerization involves the joint use of a polyfunctional monomer with the polymerizable monomer.

Star-shaped block copolymer and production process therefor

The present invention provides a photosensitive resin composition which comprises an urethane resin obtained by reacting (A) a carboxyl group-containing polymer having an acid value of 30 mg KOH/g or more and a glass transition temperature of 30&deg; C. or more, (B) a compound having two isocyanate groups in one molecule, (C) a compound having two hydroxyl groups in one molecule and (D) a photopolymerizable unsaturated monomer having one hydroxyl group in one molecule, and a photopolymerization initiator, and a resin plate for flexography using the photosensitive resin composition, whereby the photosensitive resin composition having water developing properties, high in sensitivity and impact resilience, and excellent in water resistance, ink resistance and press life of a hardened portion forming a line pattern area of a printing plate material and the resin plate for flexography prepared by the use of the photosensitive resin composition can be provided.

Photosensitive resin composition and flexographic resin plate

The invention provides a thermally reversible crosslinked matter, which displays a sufficiently low melt viscosity during heating and is also excellent in the stability of the melt viscosity, and further provides a hot melt resin comprising this crosslinked matter. The thermally reversible crosslinked matter comprises a compound (A)-based moiety and a compound (B)-based moiety, wherein both moieties are bonded to each other through a crosslinked structure, which is characterized in that: the crosslinked structure includes a structure making steric hindrance, and breaks due to heating and then reverts due to cooling; and when the crosslinked structure breaks due to heating, the melt viscosity of the thermally reversible crosslinked matter decreases to not higher than twice the melt viscosity of compound (A) alone or the melt viscosity of compound (B) alone, whichever is higher, as heated at the same temperature that the thermally reversible crosslinked matter is heated at.

Thermally reversible crosslinked matter and its use

An inexpensive block polymer which is effectively available in various uses with regard to hot-melt resin compositions, pressure sensitive adhesives, carriers for pressure sensitive adhesives, and the like. This block polymer has a structure including a polyvalent mercaptan segment at its center from which two or more polymer segments are radially extended. The number-average molecular weight of this polymer is in a range of 2,000 to 1,000,000, and the two or more polymer segments have two or more different compositions. This block polymer is obtainable by a process including two or more steps of radical polymerization of polymerizable monomer components having different compositions using a polyvalent mercaptan as a polymerization initiator.

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Osaka, Japan

Nobuhiro Kobayashi