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. 12, 1994
Filed:
Oct. 14, 1992
Akira Ibi, Chiba, JP;
Toshimi Ogata, Chiba, JP;
Yoshihiro Nodate, Chiba, JP;
Takayuki Kageyama, Chiba, JP;
Mitsui Toatsu Chemicals, Inc., Tokyo, JP;
Abstract
A purification process of crude methacrylamide by recrystallization from an aqueous methacrylamide solution, comprising the steps of conducting crystallization by adjusting the hydrogen ion concentration of the aqueous methacrylamide solution to pH 8 or more, separating a methacrylamide crystal, adjusting 5% by weight or more of resulting mother liquor to pH 5 or less, separating precipitated insoluble matter, and reusing thus-treated mother liquor, is provided. The high quality methacrylamide crystal thus obtained is excellent in Hazen number, purity and transparency of a methanol solution and suitable for uses such as windshield glasses.