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:
Dec. 26, 1978
Filed:
Jan. 18, 1977
Guido Dessauer, Duesseldorf-Gerresheim, DE;
Kurt Ramlow, Schafflund, DE;
Kurt Riecke, Kempen, DE;
Franz Wirnitzer, Flensburg, DE;
Feldmuhle Aktiengesellschaft, Dusseldorf-Oberkassel, DE;
Abstract
A recording sheet consisting mainly of fibrous material is capable of displaying a colored image when contacted under pressure with substantially colorless crystal violet lactone and similar dye precursors if at least 3% of the fibrous material is constituted by uniformly distributed asbestos fibers. Sheets having adequate strength for carbonless copying should not contain more than 30% asbestos fibers. Stronger colors are obtained if the sheet further contains a mixture of .gamma.-alumina and .gamma.-alumina precursors in an amount of 2% to 20% of the weight of the fibrous material, the mixture containing 1% to 30% water volatile at 1000.degree. C, and being converted substantially entirely to .gamma.-alumina when heated from 300.degree. to 1000.degree. C.