| 摘要 |
Light polarizing film materials comprise a molecularly oriented layer formed from a high molecular weight, hydroxyl group containing vinyl polymer, a high molecular weight basic nitrogen-containing polymer, a cross linking agent selected from dimethylol urea, boric acid, glyoxal and diphenyl diisocyanate, and at least one dichroic direct cotton dye containing acidic or phenolic groups. The preferred hydroxyl group containing polymer is polyvinyl alcohol. Specified nitrogen-containing polymers are polyvinyl acetals of amino aldehydes, deacetylated chitin, beta-diethylaminoethyl methacrylate polymers and polyvinyl pyridine quaternary ammonium salts. The nitrogen-containing polymer and cross-linking agent may be added to casting solutions of the hydroxyl-containing polymer or imbibed into the cast films. Alternatively the nitrogen-containing polymer may be prepared in situ by acetalizing polyvinyl alcohol with an amino aldehyde. The dye may be applied uniformly or differentially by imbibition, printing or transfer to produce polarizing sheets or images, e.g. stereoscopic pairs of monochromatic or coloured images.
|
