Asahi Kasei Kogyo Kabushiki Kaisha

Kazuki Ban

Masatoshi Tanouchi

Hiroshi Takeuchi

Tetsuya Miyake

Yoshiyuki Asahina

Tatsushi Saeki

Norio Oyabu

A urethane prepolymer composition is provided comprising (a) a terminal isocyanate group-containing urethane prepolymer derived from a polytetramethylene glycol having a specific molecular weight of 700 to 1500 and an aliphatic and/or alicyclic diisocyanate and (b) a terminal isocyanate group-containing urethane prepolymer derived from a polycaprolactone diol and/or polyol having a specific molecular weight of 500 to 1500 and an aliphatic and/or alicyclic diisocyanate, the weight ratio of (a) to (b) being in the range of 80/20 to 20/80. This composition has excellent compatibility with a diol compound and/or a polyol compound, and can be formulated together with the diol compound and/or the polyol compound into a polyurethane coating composition system which forms a coating film having not only excellent weathering resistance, elastic recovery and transparency but also excellent low-temperature physical properties such as mechanical strength, flexibility and impact resistance at low temperatures, e.g., -30.degree. C. The composition system is useful for protecting and providing a good appearance to resin products, such as polyurethane bumpers and facing materials for buildings.

Urethane prepolymer composition and a polyurethane coating composition

A process for recovering heavy metal ions or heavy metal ions and halogen values from a solution comprising a lower aliphatic monocarboxylic acid, which comprises the steps of:

Process for recovering heavy metal ions or heavy metal ions and halogen

This invention relates to an improved process for recovering highly pure terephthalic acid crystals from a suspension containing terephthalic acid product obtained by the liquid phase oxidation of para-substituted aromatic compounds in the presence of oxidizing catalyst. The improvement comprises bringing said suspension into continuous countercurrent contact with ascending hot acetic acid containing water in a single tower under the conditions of specified temperature, specified ascending rate of the acetic acid containing water and specified residence time of the suspension, to replace the mother liquor of the suspension with said acetic acid, and recovering the mother liquor as an overflow, while recovering terephthalic acid as an underflow in the form of suspension of highly purified crystals and, if necessary, allowing the suspension to stay in a stirring tank.

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Nobeoka, Japan

Kazuki Ban