The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 15, 1980
Filed:
Mar. 20, 1979
Nagao Ariga, Chiba, JP;
Minoru Yamamoto, Ichihara, JP;
Katsuji Takahashi, Chiba, JP;
Takehisa Mizuno, Ichihara, JP;
Dainippon Ink & Chemicals, Inc., Tokyo, JP;
Abstract
A process is provided for isomerizing (1) cis-3-methyl-.DELTA..sup.4 -tetrahydro-cis,cis-phthalic anhydride into (2) trans-3-methyl-.DELTA..sup.4 -tetrahydro-cis,cis-phthalic anhydride, which is its stereoisomer, by heating the compound (1) preferably at a temperature of 100.degree. to 250.degree. C. in the presence of an alkali metal compound such as lithium hydroxide, sodium hydroxide or sodium acetate. A mixture of said compounds (1) and (2) in a ratio by weight of 7:3 to 2:8 obtained by the isomerization reaction is liquid at room temperature and can be used advantageously as a curing agent for epoxy resins.