Kureha Corporation

Fuminori Kobayashi

Hiroyuki Sato

Fumio Akutsu

Kazuyuki Yamane

Hikaru Saijo

Yuki Hokari

Takeo Takahashi

Takuma Kobayashi

Yasushi Okada

Katsushi Momose

Yoshinori Suzuki

Takahiro Watanabe

Yukichika Kawakami

Takashi Sato

Masayuki Okura

Toshihiko Ono

Tatsuaki Miyashita

Yoshikazu Amano

Takenori Tose

Mizuki Saito

Motoharu Shoda

Hiroaki Yoshida

To provide a downhole tool that can maintain a high degradation rate even in high-temperature environments and a method for well drilling using the downhole tool. A downhole tool including: a component containing a reactive metal; and a component containing a degradable resin composition promoting degradation of the reactive metal, the degradable resin composition containing a degradable resin producing an acid by degradation, wherein a molar ratio of a maximum amount of the acid which the degradable resin composition is capable of producing to a content of the reactive metal is 1.0 or higher.

Downhole tool and well-drilling method

A downhole tool that has a high initial compressive strength, can maintain compressive strength for a certain period of time, and is rapidly degradable after use. The downhole tool is formed from a degradable resin composition containing a polyamide resin and a carboxylic acid anhydride, and the carboxylic acid anhydride is a compound satisfying the following melting point condition:melting point of polyamide resin&#x2264;5% weight reduction temperature of carboxylic acid anhydride.

Downhole tool

A rubber composition for downhole tools having excellent degradability and storability is provided. The rubber composition for downhole tools includes degradable rubber, a degradation accelerator, and a degradation inhibitor. The degradation accelerator is at least one type of the compound represented by Formula (I) or Formula (II) below. The degradation inhibitor is at least one type selected from the group consisting of carbodiimide compounds, oxazoline compounds, oxazine compounds, and epoxy compounds. The content of the degradation accelerator is from 0.1 to 20 parts by mass relative to 100 parts by mass of the degradable rubber. The content of the degradation inhibitor is from 0.1 to 3 parts by mass relative to 100 parts by mass of the degradable rubber.

Rubber composition for downhole tools and member for downhole tools

A composition for downhill tool, a degradable rubber member for a downhole tool, a downhole tool, and a method for well drilling are provided which contribute to cost reduction and process shortening and can contribute to improvement of production efficiency. A degradable rubber and a degradation accelerator comprising at least one type of compounds represented by a general formula (I) below at the ratio from 0.1 to 20 parts by mass to 100 parts by mass of the degradable rubber, containing the composition for a down hole tool, i.e. degradable rubber member for a down hole tool, and a method for well drilling using them. (In Formula (I), Rand Rare each individually alkyl groups having from 1 to 5 carbons or phenyl groups).

Composition, composition for downhole tools, degradable rubber member for downhole, downhole tool, and method for well drilling

A composition for downhill tool, a degradable rubber member for downhole tool, a downhole tool, and a well drilling method are provided which contribute to cost reduction and process shortening and can contribute to improvement of production efficiency. The composition comprises a degradable rubber and a decomposition accelerator and comprises 0.1 to 20 parts by mass of at least one type of compound represented by the following general formula (I) per 100 parts by mass of the degradable rubber, the composition for a down hole tool includes the same, the degradable rubber member for down hole tool includes the same, and a well drilling method using the same. (In formula (I), R is an alkyl group having from 2 to 6 carbons).

Provided is a molded article comprising an aliphatic polyester. The aliphatic polyester is at least one selected from the group consisting of polyglycolic acid and a copolymer of a glycolic acid monomer and a monomer other than the glycolic acid monomer. The molded article has a uniaxial compressive strength at a temperature of 23&#xb0; C. of greater than 250 MPa and not greater than 350 MPa.

Molded article and use of same

A stock shape for a downhole tool component includes a magnesium alloy including a phase containing 70 to 95 wt. % of magnesium in which 0 wt. % or more and less than 0.3 wt. % of a rare earth metal, a metal material other than the magnesium and the rare earth metal, and 0.1 to 20 wt. % of a degradation accelerator are distributed, and the stock shape has an average particle size of the metal material of 1 to 300 &#x3bc;m, tensile strength of 200 to 500 MPa, and a degradation rate in a 2% potassium chloride aqueous solution at 93&#xb0; C. of not less than 20 mg/cmand not greater than 20000 mg/cmper day. Accordingly, a downhole tool having high strength and being readily degradable is established.

Stock shape for downhole tool component, downhole tool component, and downhole tool

The polyglycolic acid having a content of low molecular weight substance of less than 1% by weight; and a molded article thereof having a thickness of 2 mm or greater, the time at which immersion of the molded article in water at 66&#xb0; C. is started to the time at which the polyglycolic acid decomposed by the water starts to elute being 1 hour or longer by 30 hours or shorter, and a rate of embrittlement, at which embrittlement proceeds due to the elution of the polyglycolic acid, being 0.025 mm/h or greater.

Polyglycolic acid molded article, component for downhole tool, and method of producing polyglycolic acid molded article

A method to efficiently produce an aliphatic polyester and to improve the thermal stability of the resulting aliphatic polyester. A sulfonic acid compound is used as a co-catalyst at the time of a ring-opening bulk polymerization of a cyclic ester using a tin compound catalyst.

Production method for aliphatic polyester

In the production of an aliphatic polyester by ring-opening polymerization of a cyclic ester, at least a latter period of polymerization is proceeded with by way of solid-phase polymerization, and the resultant aliphatic polyester is subjected to removal of residual cyclic ester. As a result, an aliphatic polyester with a minimized content of residual monomer is obtained.

Process for producing aliphatic polyester reduced in residual cyclic ester content

A polyglycolic acid resin composition having improved moisture resistance is obtained by adding a carboxyl group-capping agent and a polymerization catalyst-deactivation agent to a polyglycolic acid resin.

Polyglycolic acid resin composition

A method of controlling a moisture resistance of polyglycolic acid resin, by controlling a total carboxyl group-source concentration including a contribution of residual glycolide. As a result, a moisture resistance governing the change of strength with time of the polyglycolic acid resin is controlled at a good accuracy.

Method for controlling water resistance of polyglycolic acid resin

A particulate polyglycolic acid resin composition, comprising: a blend of a first particulate polyglycolic acid resin and a second particulate polyglycolic acid resin each having a moisture content of at most 110 ppm and providing a ratio of melt-viscosity (as measured at 270&#xb0; C. and a shear rate of 121 sec; the same as hereinafter) therebetween of above 1 and at most 10. After the polymerization, the first and second particulate polyglycolic acid resins can cause change in properties before the forming (e.g., during storage); or during the forming process. However, by adequately determining the blending ratio between the resins while taking the melt-viscosities thereof into account, it becomes possible to provide a particulate polyglycolic acid resin composition showing a stable melt-formability and suitable as a starting material for various forming processes.

Polyglycolic acid resin particle composition and process for production thereof

An aromatic polyester resin composition, including: a melt-kneaded product of 99-70 wt. parts of an aromatic polyester resin and 1-30 wt. parts (providing a total of 100 wt. parts together with the aromatic polyester resin) of a polyglycolic acid resin, wherein the aromatic polyester resin is an aromatic polyester resin polymerized with a germanium compound (catalyst), and the polyglycolic acid resin is a polyglycolic acid resin obtained by ring-opening polymerization of glycolide. As a result, gas generation during the melt-processing of a composition obtained by adding a relatively small amount of polyglycolic acid resin to an aromatic polyester resin is effectively suppressed to provide an aromatic polyester resin composition with a good gas-barrier property.

Aromatic polyester resin composition

An aromatic polyester resin composition, comprising: a melt-kneaded product of 99-70 weight parts of an aromatic polyester resin and 1-30 wt. parts (providing a total of 100 wt. parts together with the aromatic polyester resin) of a polyglycolic acid resin, wherein the composition is characterized by a transesterification rate C(%) of 20-60% determined by formula (1) below based on a peak integration ratio of methylene group in polyglycolic acid appearing at &#x3c3;4.87 ppm with reference to tetramethylsilane according toH-NMR measurement:(%)=(1&#x2212;()/())&#xd7;100&#x2003;&#x2003;(1),wherein I (A): a peak integration ratio of the methylene group of the polyglycolic acid main chain with respect to the alkylene group of the aromatic polyester main chain calculated from the components weight ratio; and I (B): a peak integration ratio of the methylene group of polyglycolic acid main chain to the alkylene group of the aromatic polyester main chain in the resin composition. As a result, the aromatic polyester resin composition obtained by adding a relatively small amount of polyglycolic acid resin is provided with a good harmony of gas-barrier property and transparency.

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Tokyo, Japan

Fuminori Kobayashi