Hitachi Chemical Company, Ltd.

Masatoshi Yoshida

Susumu Konii

Yasuo Miyadera

Shigeo Sase

Shoei Kuroda

Takeshi Sumi

Masami Yusa

Katsuji Shibata

Mitsumasa Kojima

Hidetaka Satou

Yukio Yoshimura

Toshihiko Kato

Takehiko Ishibashi

Shizuo Sakamoto

Disclosed herein are processes for the preparation of polyimide-isoindroquinazolinediones and precursor thereof. These polymers are useful as heat-resistant electric insulation materials, surface coating films for electronic instrument parts and especially suitable for manufacturing a photoresist. The above precursor is produced by reacting a an alkylenebistrimellitate dianhydride, a diaminoamide compound and the other amine. The precursor is readily dehydrated and ring-closed to produce polyimide-isoindroquinazolinedione, which is often conveniently conducted by producing a varnish of the precursor, applying it onto adequate substrates such as silicon wafers, glass plates, metal plates, etc. and then subjecting the coated film to dehydration. The resulting films have excellent physical properties such as good adherence, high tensile strength, low elasticity, etc.

Processes for preparation of polyimide-isoindroquinazolinedione and

A transparent and homogeneous polyimide resin solution produced by a process in which a tetracarboxylic acid component and an aromatic diamine component are subjected to polymerization and imidization by one step at 100.degree. to 200.degree. C. by use of a halogenated phenolic compound as a solvent, permits the formation of a polyimide film excellent in mechanical properties.

Process for producing a polyimide solution

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

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

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Shimodate, Japan

Masatoshi Yoshida