Toyo Seikan Group Holdings, Ltd.

Toyo Seikan Kaisha, Ltd.

Kureha Corporation

Tsutaki Katayama

Seishi Yoshikawa

Masahito Kogure

Toshiki Yamada

Kazuyuki Yamane

Koki Shibata

Kouki Shibata

Yoshikawa Seishi

A polylactic acid solid composition includes: a polylactic acid having a weight average molecular weight of not more than 40,000, which is measured in terms of polystyrene standard by GPC; and a basic compound of an alkali metal or an alkaline earth metal, which is a residue of a molecular weight reduction accelerator. The basic compound is contained in an amount in a range of 0.5 to 20 mass %.

Polylactic acid solid composition and method for producing the same

A method of extracting underground resources including a step of mixing hydrolysable particles and a proppant to an aqueous dispersion fluid, and introducing the fluid with pressure into an ore chute formed under the ground, wherein as the hydrolysable particles, use is made of spherical particles that include a hydrolysable resin of a weight average molecular weight (Mw) of not less than 5,000 and, specifically, not less than 10,000, and that have an average particle size (D) in a range of 300 to 1,000 &#x3bc;m, and a circularity of a short diameter/long diameter ratio of not less than 0.8. The spherical particles have a hyrolysable capability, a circularity and a particle size adapted to the hydraulic fracturing.

Method of extracting underground resources by using hydrolysable particles

A polylactic acid composition of a dispersion structure using, as a matrix, a lowly crystalline or amorphous polylactic acid having a crystallinity of not more than 40%, the matrix containing, as a pulverization promotor dispersed therein, an organically modified polysaccharide or a lamellar silicate that is swollen or that is treated to be swollen. The polylactic acid composition has excellent hydrolysable capability and property of being mechanically pulverized.

Polylactic acid composition

A method of extracting the underground resources by pressurizing a fluid filled in an ore chute in which cracks are formed and by, further, forming or growing the cracks, the underground resources being extracted through the cracks, wherein a hydrolysis-blocking agent is introduced with pressure into the fluid to block a diverting agent that works to temporarily close the cracks.

Method of extracting underground resources and hydrolysis-blocking agent for use in the method

A powder comprising hydrolyzable resin particle, containing particles which do not pass through a sieve having an opening size of 500 &#x3bc;m in an amount of 50 mass % or more and having a repose angle of 51&#xb0; or more. This powder is preferably used as an additive for drilling to enhance the drilling properties of a drilling fluid and improve the retentivity of a fracture extending from a winze.

Powder comprising hydrolyzable resin particles

A dispersion solution for drilling obtained by dispersing, in an aqueous medium, a hydrolysable resin material that contains a resin that is hydrolysable but sparingly and a hydrolysable resin that accelerates the decomposition of esters. The dispersion solution for drilling exhibits a highly hydrolysable capability despite of using an inexpensive hydrolysable resin material, and can be favorably used for extracting resources relying on a well drilling method such as hydraulic fracturing method, rotary drilling method or riserless drilling method.

Dispersion solution for drilling and method of extracting underground resources using the dispersion solution

An object of the present invention is to provide a method for efficiently degrading a biodegradable resin. In particular, the present invention relates to a method for degrading a biodegradable resin, the method comprising degrading the biodegradable resin in a buffer solution containing a biodegradable resin-degrading enzyme having an optimum pH of 7.5 or higher, wherein no anion derived from a buffer component is present on one side of an equilibrium equation of buffering of the buffer solution, and a pH of the buffer solution is adjusted within a pH range which gives conditions for shifting the equilibrium towards the side on which no anion is present. Further, the present invention relates to a method for degrading a biodegradable resin, the method comprising degrading the biodegradable resin in an enzymatic reaction liquid containing a biodegradable resin-degrading enzyme having an optimum concentration, wherein the degradation is conducted in a reaction liquid having an enzyme concentration which gives a biodegradable resin degradation ratio of 60% or higher, where a biodegradable resin degradation ratio at said optimum concentration is referred to as 100%.

Method for degrading biodegradable resin

A method for degrading a readily degradable resin composition comprising an aliphatic polyester (A) which is biodegradable, and an aliphatic polyester (B') which releases an acid upon hydrolysis and which is biodegradable at a higher degradation rate than that of the aliphatic polyester (A), the method comprising degrading the readily degradable resin composition in an enzyme reaction liquid containing a degradation enzyme, and an acid neutralizing agent incompatible with the enzyme reaction liquid.

Method for degrading a readily-degradable resin composition

An object of the present invention is to provide a method for efficiently producing an oligomer or a monomer by degrading a biodegradable resin using an enzyme, so that the oligomer or the monomer can be recovered. The present invention provides a method for producing an oligomer and/or a monomer by degrading a biodegradable resin in a degradation liquid containing a biodegradation enzyme, a buffer agent, an organic solvent, and water. In this method, the SP value of the organic solvent is less than 8.5 or more than 11.5, and the percentage content of the organic solvent (by volume) in the degradation liquid is higher than 1% and lower than 15%. In the method for producing an oligomer or a monomer, the degradation percentage of the biodegradable resin is low, and deposits of aggregates of the oligomer and/or the monomer are few, so that the recovery percentage is high.

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Yokohama, Japan

Tsutaki Katayama