Kanegafuchi Kagaku Kogyo Kabushiki Kaisha

Toshinobu Nakata

Hidenari Tsunemi

Shigeki Hamaguchi

Hiroshi Ando

Koyoyuki Namura

The present invention provides a powder coating having an excellent curability which can be baked without evaporation of a blocking agent as compared with the conventional powder coating to provide a coat having an excellent yellowing resistance an improved smoothness and weather resistance. A novel powder coating containing, as a main component, a polyester resin composition is provided, comprising (A) an alkenyl group-containing polyester resin with a number-average molecular weight of from 500 to 100,000 having at least 1.2 alkenyl groups on the average per molecule, (B) a Si--H group-containing curing agent having at least two Si--H groups per molecule, and (C) a catalyst active in hydrosilylation.

Powder coating comprising novel curable polyester composition

Dislcosed is a curable composition of a partially trimerized prepolymer of the dicyanate ester of the formula ##STR1## wherein R.sub.1 and R.sub.2 are the same or different and each is alkyl, perfluoroalkyl, aryl or halogen; and A is a bridge selected from the group consisting of a direct bond, methylene optionally mono- or disubstituted by alkyl, perfluoroalkyl and/or aryl, a five or six membered cycloalkylene, sulfonyl, thio, oxy, carbonyl, phenylene, and xylylene optionally substituted by alkyl at on or both methylene carbon atoms is useful in the manufacture of electrical laminates having excellent dielectric properties in the GHz region.

Bifunctional aromatic cyanates, prepolymers and electrical laminates

A novel dicyanate ester of the formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different and each is hydrogen, alkyl, perfluoroalkyl, aryl or halogen; A is a bridge selected from the group consisting of direct bond, methylene optionally mono- or di-substituted by alkyl, perfluoroalkyl and/or aryl, a five or six membered cycloalkylene, sulfonyl, thio, oxy, carbonyl, phenylene, and xylylene optionally substituted by alkyl at one or both methylene carbon atoms; with the proviso that when the cyanato group is at the para-position relative to the bridge A, both R.sub.1 and R.sub.2 are not hydrogen, and its prepolymer are useful in the manufacture of electrical laminates having excellent dielectric properties in GHz region.

A flame-retarded thermosetting resin composition is provided by blending about 5 to 45 mole % of a phenylcyanate having at least one halogen substituent at the ortho or para position relative to the cyanato group, and about 55 to 95 mole % of a halogen-free bis-4-phenylcyanate. A flame retardancy of V-O grade of UL94 is achieved in the thermoset resin of the composition without compromising dielectric, heat resistance, moisture absorption and other properties.

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Otsu, Japan

Toshinobu Nakata