Dai-ichi Kogyo Seiyaku Co., Ltd.

Takashi Sano

Hirohisa Maki

Hidehiro Uchikata

Yoji Miya

Kazuo Kawabata

Misao Yamamoto

The invention relates to a polyether polyol, a water-curable polyurethane prepolymer prepared by using the polyether polyol, and a composition containing the prepolymer. The above polyether polyol is obtainable by subjecting an active hydrogen compound to addition polymerization reaction with ethylene oxide and an alkylene oxide of 3 to 4 carbon atoms in a specified ratio. The above water-curable polyurethane prepolymer is obtainable by reacting the polyether polyol with a polyisocyanate compound. The above composition comprises a mixture of the water-curable polyurethane prepolymer and the polyisocyanate. The above water-curable polyurethane prepolymer and composition provide a foam of fine and uniform cell structure with improved strength on curing with water.

Polyether polyols, water-curable polyurethane prepolymers based thereon,

A urethane prepolymer composition useful as sealant is disclosed. The composition comprises a reaction product of an organic polyisocyanate and a polyether polyol mixture at an NCO/OH equivalent ratio from 1.6 to 2.5. The polyether polyol mixture contains (a) from 75 to 95 % by weight of the mixture of a polyoxyalkylenediol having an average MW from 400 to 1,000 and an oxyethlene unit content greater than 50 % by weight, and (b) the balance of the mixture of a polyoxyalkylenetriol having an average MW from 5,000 to 10,000 and an oxyethylene unit content greater than 50 % by weight. An equivalent composition is produced by reacting the polyoxyalkylenediol and polyoxyalkylenetriol with the organic polyisocyanate separately and mixing together after the reaction.

Hydrophilic urethane prepolymer composition

A method of forming a coating on a polyolefin substrate comprising the steps of applying a primer coating onto the substrate and then applying a finish coating is disclosed. The method is characterized in that the primer coating consists essentially of a polyurethane prepolymer derived from a polypropylene glycol having a molecular weight from about 400 to about 2,000 and an excess of diphenylmethane diisocyanate.

Method of forming a coating on polyolefin substrate

An anti-corrosive polyurethane coating composition which has excellent anti-corrosive property, water resistance, adhesive property to metals and impact resistance and can be coated thick in one coating operation, comprising (1) a polyol mixture of castor oil or a polyol derived from castor oil and an amine polyol produced by addition reaction of an alkylene oxide to a nitrogen-containing compound having at least 2 active hydrogen atoms such as ammonia, an aliphatic amine or an aromatic amine, the amine polyol having at least 2 hydroxyl groups and a hydroxyl value of at least 150 mgKOH/g, (2) a polyisocyanate compound, and optionally coal tar, an aromatic hydrocarbon oil or resin, or usual paint additives.

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Otsu, Japan

Takashi Sano