Mitsubishi Chemical Corporation

The Nippon Synthetic Chemical Industry Co., Ltd.

Chizuko Furo

Takahiro Saka

Shusaku Mandai

Ryosuke Taniguchi

Yasuhiro Hirano

Tomoya Fujita

Norihito Sakai

Taiji Kanda

Kazutoshi Tsuji

Takeshi Kuroda

Hirofumi Takeuchi

Ken Sato

Ayaka Kobayashi

Kenji Shinohara

Yuya Kanamori

Kenji Furui

Koji Hara

Pankaj Hanumantrao Jadhav

Yoshiko Takeuchi

Pradeep Ratilal Vavia

Jasmin Dhirajlal Monpara

A diverting agent is provided which does not completely dissolve in water and seawater in an ultra-low temperature to low temperature range (5° C. to 30° C.) for a certain period of time (about 5 minutes to 3 hours), and is quickly dissolved and removed after a certain period of time in an excavation method using a hydraulic fracturing method. Also provided is a diverting agent containing a polyvinyl alcohol-based resin having 2.3 mol % to 15 mol % of a hydrophilic modifying group in a molecular structure thereof.

Diverting agent and method of filling fracture in well using same

An object of the present invention is to provide a diverting agent that can exhibit sufficient filling properties against a fracture in a well in an excavation method using a hydraulic fracturing method, and that is excellent in solubility after a predetermined period of time has passed. The diverting agent of the present invention contains a polyvinyl alcohol-based resin having an average polymerization degree of 1000 or more.

A problem to be solved of the present invention is to provide a diverting agent which gradually dissolves in water. The present invention relates to a diverting agent containing a polyvinyl alcohol-based resin and a method of filling a fracture using the diverting agent.

Diverting agent and method of filling fracture in well using the same

A diverting agent is provided that exhibits sufficient filling properties against a fracture in a well because of swelling without complete dissolution for a certain period of time (about 30 minutes to 5 hours), and that quickly dissolves and can be removed even at a low temperature of 40° C. to 60° C. after a certain period of time has passed. Also provided is a diverting agent that contains a modified polyvinyl alcohol-based resin.

A diverting agent which has performance to release filling due to biodegradability, can be quickly removed after a certain period of time, and has an excellent filling property with respect to a fracture in a well is provided. The diverting agent contains particles having a particle diameter of 1,700 μm or more in an amount of 10 to 70 mass %, particles having a particle diameter of 500 μm or more and less than 1,700 μm in an amount of 20 to 80 mass %, and particles having a particle diameter of less than 250 μm in an amount of 5 to 40 mass %, and the diverting agent contains a biodegradable resin in an amount of 10 mass % or more.

A diverting agent is provided which has solubility in water that can be controlled excellently and which does not easily dissolve at an early stage of filling of fractures in a well in excavation method using a hydraulic fracturing method and dissolves in water and can be easily removed after filling is no longer needed. The diverting agent contains powdery polyvinyl alcohol-based resins having an average particle diameter of 800 to 2000 μm.

A diverting agent of the present invention contains a polyvinyl alcohol-based resin, wherein when the diverting agent is added to a 0.48 mass % aqueous solution of guar gum to prepare a mixed solution having a concentration of 12 mass %, a dispersion liquid obtained by dispersing the mixed solution at 30&#xb0; C. for 60 minutes is pressurized and dehydrated at a pressure of 1 MPa using a pressure dehydration device including a drainage part having a slit having a width of 2 mm, and a regression line represented by an equation (A): y=ax+b (in the equation (A), y is a cumulative dehydration amount (g), x is a square root of a time (minutes) elapsed from start of pressurization, a and b are a slope and an intercept of the regression line, respectively, and 0&#x3c;x&#x2264;2) is calculated by a least squares method from a scatter diagram plotted on a graph in which the square root x of the time is plotted on a horizontal axis and the cumulative dehydration amount y is plotted on a vertical axis, a slope a of the equation (A) satisfies a condition (B): a&#x2264;80.

An object of the present invention is to provide a pharmaceutical tablet having high tensile strength and excellent in immediate disintegrability. The pharmaceutical tablet of the present invention is obtained by a direct compression method, and contains an active ingredient, a polyvinyl alcohol resin, and a plasticizer other than water, wherein a content of the plasticizer is 1 to 8 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin.

Pharmaceutical tablet and production method thereof

The diverting agent of the present invention contains resin particles of polyvinyl alcohol-based resin. The resin particles of polyvinyl alcohol-based resin are a particle mixture containing two or more types of resin particles having different particle diameters, and the diverting agent contains resin particles A of polyvinyl alcohol-based resin having a particle diameter of 1,700 &#x3bc;m or more in a range of 5 mass % to 95 mass % and resin particles B of polyvinyl alcohol-based resin having a particle diameter of 250 &#x3bc;m to 1,000 &#x3bc;m in a range of 5 mass % to 95 mass %.

Provided is a liquid spray agent for agricultural use, including a polyvinyl alcohol-based resin having a saponification degree of from 30 mol %, to 60 mol %. With this, a liquid spray agent for agricultural use, which is used in agricultural and horticultural fields and has high fixation ability and excellent sprayability, can be provided.

Liquid spray agent for agricultural use

A cement admixture includes a crosslinked product of a modified polyvinyl alcohol-based resin, wherein the dissolution rate of 1 g of the crosslinked product of a modified polyvinyl alcohol-based resin for 1 liter of water at 70&#xb0; C. is 50% or less.

Cement admixture

Disclosed is a dispersing agent for agrochemicals, said dispersing agent which comprises a modified polyvinyl alcohol-based resin containing a structural unit having a nonionic hydrophilicity group in side chain, and having a saponification degree of 95 mol % or more. The dispersing agent for agrochemicals can provide a dispersion in which a hardly water-soluble agrochemical active ingredient employed for a dispersoid is dispersed in a stable state even in the case where the dispersoid has a relatively large particle size.

Dispersing agent for agrochemicals and fluid dispersion using the same

Provided herein is a polyvinyl alcohol fine particle suitable for a pharmaceutical binder for obtaining a pharmaceutical tablet of properties including good sustained release, high hardness, and excellent friability. The polyvinyl alcohol fine particle of the present invention contains 25 mol % or more of a gauche structure in polyvinyl alcohol molecules within a 0.8-nm region inside the particle from the particle surface.

Polyvinyl alcohol particles, pharmaceutical binder using same, pharmaceutical tablet, sustained-release pharmaceutical tablet, and method for producing polyvinyl alcohol particles

An object of the invention is to provide a crosslinking agent with which a crosslinked polymer that suffers little coloring with the lapse of time and shows excellent viscosity stability is obtained. The crosslinking agent of the invention includes a compound which contains two or more alkylhydrazide groups represented by the following general formula (1). (In formula (1), Rrepresents an alkyl group having 1-10 carbon atoms, and symbol * is a linking bond.)

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Osaka, Japan

Chizuko Furo