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US 4,362,895 AGranted
Ultraviolet absorbing copolymers
AssigneeCalifornia Institute of Technology
InventorsAmitava Gupta, Andre H. Yavrouian
Life of this patent
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Abstract
Photostable and weather stable absorping copolymers have been prepared from acrylic esters such as methyl methacrylate containing 0.1 to 5% of an 2-hydroxy-allyl benzophenone, preferably the 4,4' dimethoxy derivative thereof. The pendant benzophenone chromophores protect the acrylic backbone and when photoexcited do not degrade the ester side chain, nor abstract hydrogen from the backbone.
Claims6
A coated article comprising a photolabile substrate containing a coating of an addition polymerized copolymer of a monomer mixture comprising:
- an acrylic ester of the formula:
- ##STR3## where R.sup.1 is hydrogen, alkyl of 1 to 6 carbon atoms and R.sup.2 is alkyl of 1 to 6 carbon atoms;
- and
- 0. 1 to 5% of hydroxy-benzophenone of the formula ##STR4## where R.sup.3, R.sup.4, R.sup.5, R.sup.3', R.sup.4', R.sup.5' are individually selected from H, OR.sup.6 or Z where R.sup.6 is methyl, ethyl or propyl and Z is --CH.sub.2).sub.m --CH.dbd.CH.sub.2 where m is 1 or 2 and at least one but no more than two of R.sup.3, R.sup.4, R.sup.5, R.sup.3', R.sup.4' or R.sup.5' are Z.
1 more element
Dependencies are inferred from the claim text.