Kuraray Co., Ltd.

Takuma Kaneshima

Keisuke Morikawa

Yusuke Amano

Ghebrehiwet Ghebremeskel

Naoki Fujiwara

Yosuke Kumaki

Katsuji Ujita

Kensuke Nagashima

Amanda Reneau

Disclosed are particulate compositions comprising particles of a blend of one or more polyvinyl alcohol polymers with one or more aliphatic polyester polymers, wherein such particulate compositions are useful, for example, as plugging agents for treatments applied to a subterranean formation traversed by the borehole of an oil or gas well.

Polyvinyl alcohol-based particulate compositions

A particulate compacted copolymer polyvinyl alcohol-based composition that can be used as a plugging agent for minimizing or eliminating loss of circulation of fluids during the process of well drilling, workover, completion and cementing in the production of oil and gas.

Particulate plugging agent based on hydrophobically-modified vinyl alcohol polymers

The present invention provides an industrially advantageous method for producing vinyl alcohol polymers having a low degree of polymerization using a chain transfer agent having an aliphatic hydrocarbon group having 6 to 12 carbon atoms, the method being capable of producing a vinyl alcohol polymer whose aqueous solution has excellent viscosity stability. The present invention relates to a method for producing vinyl alcohol polymers, including: polymerizing a vinyl ester monomer (a) in the presence of a polymerization initiator (B) and a chain transfer agent (C) having an aliphatic hydrocarbon group having 6 to 12 carbon atoms to obtain a vinyl ester polymer (A); and saponifying the vinyl ester polymer (A) at a concentration of 40 mass % or more and 75 mass % or less in the presence of an acidic catalyst (D) to obtain a vinyl alcohol polymer, wherein the vinyl alcohol polymer has a viscosity-average degree of polymerization of 160 or more and 400 or less.

Method for producing vinyl alcohol polymers

Provided is a crude oil dispersion stabilizer containing a vinyl alcohol-based polymer, wherein a degree of saponification of the vinyl alcohol-based polymer is greater than 70 mol % and 82 mol % or less, and the total content of carboxyl groups and lactone rings is 0.02 to 1 mol % relative to all structural units of the vinyl alcohol-based polymer. According to this, there is provided a crude oil dispersion stabilizer capable of dispersing or emulsifying a highly viscous crude oil, thereby reducing the viscosity and allowing the resulting crude oil dispersion liquid or emulsion to be present stably for a long time.

Crude oil dispersion stabilizer

Provided are (1) a vinyl alcohol graft copolymer grafting polymerizable unsaturated monomers as a graft chain onto a side-chain mercapto group-containing vinyl alcohol polymer backbone, the graft chain being attached to the polymer backbone at a mercapto group, and the backbone including: a vinyl alcohol unit and a unit represented by the following formula (I): wherein Ris a hydrogen atom or a carboxyl group; Ris a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group; and X is a divalent Cgroup which contains a carbon atom and a hydrogen atom and may contain a nitrogen atom and/or an oxygen atom; and (2) an ion-exchange membrane having controlled swelling in water and excellent flex resistance, the membrane including a vinyl alcohol graft copolymer as described above.

Vinyl alcohol-based graft polymer, method for producing same, and ion-exchange membrane using same

The present invention provides a vinyl alcohol polymer having a mercapto group and having excellent reactivity. The present invention is a side-chain mercapto group-containing vinyl alcohol polymer including vinyl alcohol units and structural units represented by the following formula (I) (the characters in the formula are as defined in the description): 

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Kurashiki, Japan

Takuma Kaneshima