Kureha Corporation | Date: 2015-01-30
The present invention relates to a process for producing a vinylidene fluoride polymer solution, which involves dissolving heat-treated vinylidene fluoride polymer powder into an aprotic polar solvent. The heat-treated vinylidene fluoride polymer powder is obtained by heat treating raw vinylidene fluoride polymer powder at such a temperature that the temperature of the vinylidene fluoride polymer powder is not less than 125 C. to less than a crystal melting temperature (Tm) of the polymer.
Kureha Corporation | Date: 2014-05-30
A fiber formed from a resin that degrades in treatment fluid for hydrocarbon resource recovery, an oligomer component content of a resin forming an outer surface of the fiber being not greater than 1 mass %, and a birefringence of the fiber being not less than 0.02; a method for manufacturing a degradable fiber for use in well treatment fluid, the oligomer component content of a resin that forms an outer surface of an undrawn yarn obtained in a spinning step being not greater than 1 mass %, and a birefringence of a drawn yarn before heat treatment in a drawing step being not less than 0.02; and a well treatment method using the well treatment fluid containing the degradable fiber for use in well treatment fluid and a proppant.
Kureha Corporation | Date: 2014-02-24
An object of the present invention is to provide spherical activated carbon exhibiting excellent adsorption ability for uremic substances in the body, and particularly for -aminoisobutyric acid. Accordingly, provided is an orally administered adsorbent comprising spherical activated carbon containing not less than 0.5 wt % of nitrogen atoms, having a specific surface area determined by the Brunauer-Emmett-Teller (BET) method of 700 m
Kureha Corporation | Date: 2014-11-12
A dispersion liquid for supporting oil drilling, including: an aqueous medium and a particulate solid polyglycolic acid resin dispersed in the aqueous medium; wherein the particulate polyglycolic acid resin has a weight-average molecular weight of at least 70,000 and at most 500,000, and exhibits weight retentivities in water at 80 C. of at least 85% after 12 hours, at most 80% after 72 hours, and at most 45% after 168 hours. The particulate solid polyglycolic acid resin included in the above-mentioned dispersion liquid for supporting oil drilling, functions as a fluidity control material exhibiting ideal degradation charateristics in the drilling operation for expansion of oil production capacity, demanded for suppressing the liquid permeability in the early stage and recovery of the liquid permeability after completion of the operation of the formation around the oil well.
Kureha Corporation | Date: 2015-12-28
A rubber member for downhole tools, preferably a seal member, ball sealer, ball seat, or protecting member, of which a decrease rate of 50% strain compressive stress after immersion for 24 hours in 150 C. water relative to 50% strain compressive stress before immersion is not less than 5%, and preferably not less than 50%; a downhole tool comprising the rubber member; and a method for recovering a hydrocarbon resource using the downhole tool.