Environmentally protected optical recording media

摘要

An optical recording medium comprising a transparent substrate having an information-bearing surface, a specularly reflective layer on the information-bearing surface, and a protective layer covering the other side of the reflective layer has been improved by using a new type of protective layer which comprises a polymeric network containing phosphoric acid moieties. Examples of the compounds which are cured into the protective layer in order to obtain better adhesion to aluminum protective layers are: 2-methacryloyloxyethyl phosphate, and the phosphonate ester triacrylate having the formula <IMAGE> wherein m may be 1-5. These phosphorous-containing organic compounds are radiation curable, and they are mixed with other radiation curable polymers to form the protective layer which is preferably radiation cured. Phosphorous atoms account for between about 0.05 and 0.5 weight-percent of the polymeric network within the protective layer. The improved protective layer has been found to avoid corrosion and provide better adhesion than previously known protective layers for optical recording disks such as compact audio disks and video disks.