| 摘要 |
PURPOSE:To prevent generation of flaws and contamination from the outside and to prevent generation of pitting in a recording layer at and under a high temp. and high humidity or under the conditions equiv. thereto by using a protective layer consisting of a specific UV curing type compd. CONSTITUTION:This recording medium has the protective layer 5 consisting of the UV curing type compd. having <=0.1 (KOHmg/g) acid value. The protective layer consisting of the UV curing type compd. such as acrylic acid or acrylates having <=0.1 (KOHmg/g) acid value and contg. free acid components at the lower ratio is used as the protective layer 5 in such a manner and, therefore, the pitting of the recording layer by the deterioration in which the transition metal of the rare earth-transition metal in the recording layer 3 is ionized and dissolved by the acrylic acid and acrylates remaining in the UV curing type compd. is suppressed in the cased of using an amorphous magnetic recording layer as the recording layer 3 in particular. The increase in the bit error rate (BER) after the environmental durability test of the optical recording medium is thus prevented. |
