Kuraray Co., Ltd.

Koyo Sangyo Co., Ltd.

Asahi Co., Ltd.

Kurara Co., Ltd.

Makoto Shiraishi

Tohei Moritani

Koichi Kajitani

Junnosuke Yamauchi

Hitoshi Maruyama

Takeshi Moritani

Yoshinari Tanaka

Taisei Inoue

Hiroshi Uchida

Tatsuaki Hattori

Masao Oura

Yasuaki Miyazaki

Seiichi Sakurada

Koji Moritani

Akira Saito

Sigetaka Iwata

Yoshinori Koizumi

This invention relates to a method of coating paper to improve the surface strength and printability thereof comprising applying to the paper a silicon-containing modified polyvinyl alcohol agent or its saponification product. This method gives outstanding results for printing purposes when coated onto paper objects. This invention also relates to a paper having a silicon-containing polyvinyl alcohol agents coated thereon.

Paper coating agent

A water-soluble cationic copolymer and methods for producing the same is disclosed which comprises comonomer units respectively represented by the formulae: ##STR1## wherein R.sup.1 is H or lower alkyl; B is ##STR2## R.sup.2, R.sup.3 and R.sup.4 are each independently lower alkyl or lower alkyl which contain a substituent; X is an anion capable of forming a salt with the ammonium nitrogen; and A is a group which links the nitrogen atom in B to the amide nitrogen atom. These copolymers are used in preparing paper strength additives.

Vinyl alcohol copolymers containing cationic groups

Cationic emulsions are obtained by the emulsion polymerization or copolymerization of ethylenically unsaturated monomers such as vinyl acetate, etc. in the presence of a cationic group-modified polyvinyl alcohol (PVA). Typical cationic group-modified PVA are the modified PVA's which contain a copolymeric unit having one of the following formulas: ##STR1## wherein R.sup.1 is H or lower alkyl; B is ##STR2## R.sup.2, R.sup.3 and R.sup.4 are each lower alkyl (substituted or unsubstituted) and X is an anion forming a salt with the ammonium N; and A is an inert bivalent organic group linking the N atom in B to the N atom in the amide group; ##STR3## wherein, in formulas (II) and (III), R.sup.5, R.sup.6 and R.sup.7 are each H, lower alkyl or phenyl; R.sup.8 is lower alkyl; and Y is an anion forming a salt with the imidazolinium N atom. Particularly desirable are the cationic group-modified PVA's containing the copolymeric unit (I) wherein A is ##STR4## R.sup.2, R.sup.3 and R.sup.4 each is methyl and X is chlorine, or wherein R.sup.1 is methyl, A is --CH.sub.2 --CH.sub.2 --CH.sub.2 --, R.sup.2, R.sup.3 and R.sup.4 in B are each methyl and X is chlorine, and cationic group-modified PVA's containing the copolymeric unit (II) or (III) wherein R.sup.5 and R.sup.8 are each methyl and R.sup.6 and R.sup.7 are each hydrogen. The polymers of these cationic emulsion have superior binding properties to substrates such as pulp fibers, textile fibers, glass, and the like.

Cationic polymer emulsion

Microcapsules having walls formed from polyvinyl alcohol are prepared by dispersing a substantially water insoluble nuclear material in an aqueous solution of a polyvinyl alcohol polymer, which solution has a cloud point, phase separating and depositing a concentrated aqueous solution of the polyvinyl alcohol polymer as a separated phase around said nuclear material from the bulk continuous phase by maintaining the temperature of the system above the cloud point of the aqueous polyvinyl alcohol polymer solution, and subjecting the phase separated solution to conditions which substantially solidify or gel said polyvinyl alcohol polymer in said concentrated aqueous solution of said separated phase around said nuclear material but which do not substantially solidify or gel the polyvinyl alcohol in the diluted aqueous solution of the continuous phase.

Microencapsulation process and resulting microcapsules

A method for suspension polymerizing vinyl chloride monomer, or a mixture thereof with copolymerizable monomers, employs as a suspension stabilizer a partially saponified polyvinyl alcohol having a degree of saponification between about 60 and about 90 mol percent, and a solubility-in-methanol index at 55.degree. C. in a range of up to about 60 percent.

Method for producing vinyl chloride resins

A size for textile fiber which comprises a modified polyvinyl alcohol type resin obtainable by the alkali saponification of a copolymer comprising a vinyl ester and an ethylenically unsaturated dicarboxylic acid substantially free from the monoester, diester and anhydride as essential and predominant copolymeric units. The size has excellent adhesive and cohesive strengths with respect to textile fibers as well as superior desizing properties and workability.

Sizes for textile fibers

Shaped articles of polyvinyl alcohol are prepared by saponifying a liquid feed of polyvinyl ester as it cascades downwardly along the walls of a cylindrical reactor, and by taking-up from the reactor outlet the fibrous, shaped article of oriented, solid polyvinyl alcohol thus formed at a rate of at least 50 cm/minute. Advantageously, the thus formed shaped article is next divided into sliver, stretched and cut into fibers and, optionally, beaten, which fibers are useful in the manufacture of paper-like sheet materials.

Process for preparing fibrous polyvinyl alcohol

An adhesive composition is provided comprising (1) a member selected from the group consisting of an aqueous solution of polyvinylalcohol, an aqueous emulsion of vinyl acetate polymer and an aqueous latex of butadiene polymer and (2) a hydrophobic solution of an isocyanate compound or polymer.

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Kurashiki, Japan

Makoto Shiraishi