| 摘要 |
A process for the production of an abrasion resistant layer on a transparent cellulosic sheet material comprises applying to the sheet material a thin layer of a mixture of a bis (methacrylic) ester of a polyalkylene glycol and alpha-naphthoyl peroxide as polymerization catalyst and subjecting the product to polymerization conditions to polymerize the layer. Application and polymerization of the mixture may be effected continuously, polymerization being effected either by maintaining the layer in contact with a heated surface, or in an air-free atmosphere. The transparent cellulosic sheet material may take the form of optical elements and devices, e.g. lenses, filters, sun-glasses and visors, or such elements may be cut or stamped from the coated material. The sheet material may be coated with nitrocellulose prior to the application of the mixture. The viscosity of the mixture may be increased by addition thereto of cellulose nitrate. Examples of bis (methacrylic) esters of polyalkylene glycols are di, tri, tetra, and penta ethylene glycol dimethacrylates. The abrasion resistant layer may be formed on the surfaces of a light polarizer consisting of a molecularly oriented layer of polyvinylalcohol, containing a dichroic dye or stain, between layers of a cellulosic material, e.g. cellulose acetate or acetatebutyrate.ALSO:A mixture, suitable for application to a transparent cellulosic sheet material and polymerization thereon to produce an abrasion resistant layer, comprises a bis(methacrylic) ester of a polyalkylene glycol and alpha-naphthoyl peroxide as polymerization catalyst. Application and polymerization of the mixture may be effected continuously, polymerization being effected either by maintaining the layer in contact with a heated surface, or in an airfree atmosphere. The viscosity of the mixture may be increased by addition thereto of cellulose nitrate. Examples of bis(methacrylic) esters of polyalkylene glycols are di-, tri-, tetra- and penta-ethylene glycol dimethacrylates.
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