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. 03, 1979
Filed:
Jan. 09, 1978
Hans Baumann, Wachenheim, DE;
Andreas Oberlinner, Ludwigshafen, DE;
BASF Aktiengesellschaft, Rheinland-Pfalz, DE;
Abstract
A pressure-sensitive recording material which comprises a substrate bearing a dye-forming component and a binder. The dye-forming component is a spirodipyran of the formula ##STR1## where A is the radical of a fused benzene or naphthalene ring (which rings may or may not be substituted), R.sup.1 is alkyl of 1 to 16 carbon atoms, substituted or unsubstituted phenyl or phenalkyl of 7 to 10 carbon atoms, R.sup.2 is H or together with R.sup.1 is a trimethylene or tetramethylene bridge which is unsubstituted or substituted by from 1 to 3 alkyl, R.sup.3 is benzyl or .beta.-phenylethyl and R.sup.4 is benzyl, .beta.-phenylethyl or substituted or unsubstituted phenyl, or R.sup.3 is alkyl of 1 to 4 carbon atoms and R.sup.4 is substituted or unsubstituted phenyl or R.sup.3 is benzyl and R.sup.4 is .beta.-cyanoethyl. The recording materials give violet to bluish green colorations (copies) only on paper coated with an electron acceptor.