Showing papers by "Fujiwara Naoki published in 1997"

Heat sensitive recording material

Abstract: PROBLEM TO BE SOLVED: To provide a heat-sensitive recording material, which is excellent in the preserving properties of a developed color portion, in which the color of base material is not recognized, which has so excellent color developing sensitivity as to fully allow to cope with high speed printing and further a coating layer, by employing with which a little wear of a heat-sensitive head results. SOLUTION: In this heat-sensitive recording material, a coating layer prepared by blending 0.003-1 pts.wt. alkali metal ion B to 100 pts.wt. modified polyvinyl alcohol A containing 3-15mol.% ethylene unit is provided on the surface of a base material. Since the modified PVA used is suitable for the binder for a heat-sensitive developed color layer, a surface protective layer and a bottom layer, this heat-sensitive recording material is excellent in preserving properties such as color developing sensitivity, water resistance, oil resistance, plasticizer resistance and resistance to poly vinyl chloride film. Further, since this heat- sensitive recording material is excellent in high speed printing properties and the resolution of an image, this heat-sensitive recording material is suitably used in a field, in which high speed printing such as a facsimile or the like is necessary.

Production of polymer

Abstract: PROBLEM TO BE SOLVED: To facilitate the production of a polymer comprising a combination of various polymers (graft, block, branched, and three-dimensionally crosslinked polymers) which is unobtainable by any conventional technique for copolymerization SOLUTION: An epoxidized polymer of at least one member selected from among vinyl monomers, diene monomers, and oxyalkylene monomers is reacted with a polymer having a thiol group (optionally protected) or a thioester group at one end only

Production of vinyl alcohol polymer

Abstract: PROBLEM TO BE SOLVED: To obtain a vinyl alcohol polymer having various functional groups which has not been obtained by any conventional method, by reacting a vinyl ester polymer having thioester or thiol groups with an epoxy compound and saponifying the resultant polymer. SOLUTION: A vinyl ester polymer having thioester or thiol groups is reacted with an epoxy compound and then saponified to produce a vinyl alcohol polymer. This method can give modified PVA's having various functional groups and block and graft polymers containing a PVA polymer as a component and having various functional groups. These polymers cannot be obtained by any conventional method. Thus, by selecting the kind of functional groups, a modified vinyl alcohol polymer can be obtained which is excellent in, e.g. reactivity, cross-linkability, ionic interaction, water solubility, interfacial properties or low-temp. flexibility.

Resin for melt molding

Abstract: PROBLEM TO BE SOLVED: To obtain the subject resin composed of a vinyl alcohol polymer having hydroxyalkyl group on the side chain, exhibiting remarkably excellent heat stability, especially melt-moldability at a temperature exceeding 200 deg.C and giving a molded article having excellent heat stability, impact resistance, etc. SOLUTION: This melt-molding resin is composed of a vinyl alcohol polymer containing preferably 0.1-30mol% of a 2-20C hydroxyalkyl group on the side chain. The polymer preferably has a saponification degree of >=80mol% and a viscosity-average polymerization degree of 300-5,000. The polymer is produced e.g. by copolymerizing a vinyl ester and an olefin having hydroxyalkyl group at -30 to +150 deg.C and saponifying the product in methyl alcohol at 20-60 deg.C. The vinyl ester is preferably vinyl acetate and the hydroxyalkyl-containing olefin is preferably 3-buten-1-of, etc. The resin can be incorporated with a plasticizer such as ethylene glycol to further improving the melt-moldability of the polymer.

Production of mercapto-terminated polymer

Abstract: PURPOSE: To produce industrially easily a mercapto-terminated polymer having a relatively high content of terminal mercapto groups, not undergoing oxidative insolubilization and used extensively for the production of functional polymers such as graft polymers and block polymers, the modification of polymers by various polymeric reactions and uses as a reactive dispersion stabilizer. CONSTITUTION: A radical-polymerizable ethylenically unsaturated monomer is radical-polymerized in the presence of a thiocarboxylic acid (A) and an acid (B) having an acid dissociation constant (pKa) defined by the following formula and being other than the acid A, and the obtained polymer is treated with an alkali or an acid. As for the acids (A) and (B), 1<=pKa value of the acid B other than the acid A <= pKa value of the acid A is satisfied.

High polymer based-porous body

Abstract: PROBLEM TO BE SOLVED: To obtain a polymer-based porous body having good hand feeling, flexibility and elasticity in a moist condition and capable of rapidly getting wet and softening even after once drying by acting an aldehyde and an acid to a specific water soluble modified polyvinyl alcohol SOLUTION: This polymer-based porous material is obtained by bringing to act (B) an aldehyde (eg; formaldehyde) and (C) an acid (eg; hydrochloric acid) on (A) a modified polyvinyl alcohol containing 1-24mol% ethylene unit and having >=70% saponification degree The viscosity average polymerization degree of the component A is preferably 500-2,000 The component A can be obtained by saponifying an ethylene-vinyl acetate copolymer The objective porous body can be usually obtained by adding aqueous solutions or aqueous dispersions of the components A and B to the aqueous solution of the component A in the presence of a pore forming assistant at 30-80 degC for 5-50hours 80-300mol% component B and 50-200mol% component C can be used based on one mol of component A The degree of acetalization of the objective porous body is preferably 55-80mol%