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:
Aug. 29, 1989
Filed:
Jun. 03, 1987
Clive Trundle, Towcester, GB;
The Plessey Company plc., , GB;
Abstract
The invention relates to a photochromic gamma butyrolactone having the general formula (I): ##STR1## in which X represents >CH.sub.2 or >C(CH.sub.3).sub.2 ; R.sub.1, R.sub.2 and R.sub.4 independently represent a group selected from hydrogen, alkyl or aryl (including substituted aryl), with the proviso that one of R.sub.1 and R.sub.2 is always hydrogen, and R.sub.3 is a 3-thienyl, 3-furyl, 3-benzothienyl or 3-benzofuryl group in which the 2-position is substituted with an alkyl, aralkyl or aryl group (including substituted aryl). The lactones are useful in photolithography and in the production of security inks and markings and in the production of data recording materials.