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:
Oct. 23, 2001
Filed:
Jun. 02, 2000
Optische Werke G. Rodenstock, Munich, DE;
Abstract
The invention relates to photochromic plastic objects comprising a plastic material and at least two photochromic pyran derivatives, which are introduced therein and, in each case, have an aryl group, which is linked to the carbon atom adjacent to the pyran oxygen atom and is substituted with at least one group containing at least one nitrogen atom, the longest wavelength absorption maximum of the light-stimulated form of the one pyran derivative lying above 550 nm and the longest wavelength absorption of the light-stimulated form of the other pyran derivative lying below 550 nm and the pyran derivative, absorbing at the shorter wavelength, being selected from 3[H]-naphtho[2,1-b]pyrans and the pyran derivative, absorbing at the longer wavelength, being selected from indeno[2,1-f]naphtho[1,2-b]pyrans or spiro-9-fluoreno[1,2-b]pyrans. The photochromic plastic objects of the present invention are distinguished particularly by a long service life, a good decolorization rate, by the absence of yellowing as well as by a neutral perceived color, it being possible to dispense largely or completely with the use of stabilizers and the like in the inventive plastic objects.