Hitachi Chemical Company, Ltd.

Susumu Konii

Masatoshi Yoshida

Yukio Yoshimura

Ken Nanaumi

Shigeo Sase

Takeshi Yoshida

Tzong Jeng Chu

Kohei Yasuzawa

Shoei Kuroda

Toyotaro Shinko

Takeshi Sumi

Takehiko Ishibashi

Shizuo Sakamoto

A novel process for preparing foundry cores or molds and binder materials used therefor are provided. The binder materials comprise (a) an alcohol-soluble phenolic resin, (b) a polyvalent metal hydroxide and/or oxide, (c) water, (d) an organic solvent, and (e) an alkali metal hydroxide. They are admixed with refractory particles, such as sand, and cured with carbon dioxide to form shaped foundry cores or molds. The process and materials of the invention bring about such advantages that curing may be performed with safe carbon dioxide, that shaped foundry cores or molds may be taken out from pattern immediately after curing, and that the products have a superior collapsibility after pouring a molten metal.

Process for preparing foundry cores or molds and binder materials used

Internally plasticized phenolic resins suitable for use in preparing laminates and the like excellent in electrical properties, heat resistance, solvent resistance as well as punchability are produced by reacting a compound of the formula: ##STR1## wherein R.sub.1 is an alkylene residue having 1 to 3 carbon atoms; and R.sub.2 and R.sub.3 are independently hydrogen or a saturated or unsaturated hydrocarbon group having 1 to 3 carbon atoms, with an epoxidized vegetable oil with heating in the presence of one or more secondary and/or tertiary amines, and adding formaldehyde or one or more phenols and formaldehyde to the reaction system to further proceed the reaction.

Process for producing phenolic resins

Internally plasticized phenolic resins suitable for use in preparing laminates and the like excellent in electrical properties, heat resistance, solvent resistance as well as punchability are produced by reacting a phenol-formaldehyde resin containing less than 4% by weight of unreacted free monohydric phenol or phenols with an epoxidized vegetable oil, and if required with formaldehyde, with heating preferably in the presence of one or more secondary and/or tertiary amines.

Process for producing internally plasticized phenolic resins

Resol type phenol resins containing scarcely or no phenol mononucleus compounds (monomers) and phenol dinuclei compounds (dimers) and their methylolated derivatives and scarcely containing molecules having an apparent molecular weight of more than 2500 are produced by reacting phenol with formaldehyde in the presence of an alkaline catalyst in a molar ratio of 3.0 to 6.0 moles of formaldehyde and 0.05 to 2.0 moles of the alkaline catalyst per mole of phenol, neutralizing the reaction solution with an acid to pH 4.5 to 6.5 and precipitating the resulting product for separation.

Process for producing neutralized phenol resins

A novel thermosetting resin, the thermoset resin obtained therefrom having such a thermal resistance that the temperature at which the thermoset resin is caused to show a weight loss of 6% by heating at a temperature elevation rate of 10.degree. C. per minute is at least 400.degree. C., is prepared by reacting a specific phenolic resin with a member selected from the group consisting of a silicic acid ester of the formula Si(OR).sub.4 wherein R represents alkyl or aryl and a mixture of a silicic acid ester of the formula as defined above and a titanic acid ester of the formula Ti(OR).sub.4 wherein R has the same meaning as defined above in the presence of an alkaline catalyst while keeping the reaction system in a molten state, to an extent that 20- 70 mole %, based on the phenol present in the starting system to be reacted with said member, of phenolic hydroxyl groups in terms of the amount of phenol, remain unreacted. The thus obtained novel resins of the present invention can be easily set or hardened in accordance with the ordinary manner; namely by mixing with a thermohardening agent such as hexamethylenetetramine and then heating, to give thermoset resins having a superior thermal resistance as compared with the conventional phenolic resins. In addition, the thermoset resins obtained from the novel resins of this invention are excellent in mechanical strength, electrical properties and luster of molded articles.

Novel thermosetting resins and process for preparing the same

A novel thermosetting resin, the thermoset resin obtained therefrom having such a thermal resistance that the temperature at which the thermoset resin is caused to show a weight loss of 6% by heating at a temperature elevation rate of 10.degree.C. per minute is at least 400.degree.C., is prepared by reacting a specific phenolic resin with a member selected from the group consisting of a silicic acid ester of the formula Si(OR).sub.4 wherein R represents alkyl or aryl, a titanic acid ester of the formula Ti(OR).sub.4 wherein R has the same meaning as defined above and a mixture thereof in the presence of an alkaline catalyst while keeping the reaction system in a molten state, to an extent that 20 - 70 mole %, based on the phenol present in the starting system to be reacted with said member, of phenolic hydroxyl groups in terms of the amount of phenol, remain unreacted. The thus obtained novel resins of the present invention can be easily set or hardened in accordance with the ordinary manner; namely by mixing with a thermohardening agent such as hexamethylenetetramine and then heating, to give thermoset resins having a superior thermal resistance as compared with the conventional phenolic resins. In addition, the thermoset resins obtained from the novel resins of this invention are excellent in mechanical strength, electrical properties and luster of molded articles.

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Tokyo, Japan

Susumu Konii