Optical recording medium
AssigneeTeijin Limited
InventorsEiichi Hashimoto, Tetsuo Sato, Kiyoshi Chiba
Life of this patent
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Abstract
An optical recording medium, particularly a magneto-optical recording medium, resistant to oxidation deterioration even in a hot and humid atmosphere, is provided by forming an organic protecting adhesive layer of a UV-curved resin having (1) an acid value of not more than 1.5; and (2) a softening point of not less than 50.degree. C. The UV-curved resin layer comprises 15 to 85% by weight of acrylate and/or methacrylate having at least three functionalities; 15 to 70% by weight of a compound having a linear structure and having a molecular weight of at least 300, the compound preferably having at least one ethylenically unsaturated bond and a molecular weight of at least 150 per ethylenically unsaturated bond; and (3) a photopolymerization initiator.
Claims22
An optical recording medium, comprising:
- a hard plastic substrate;
- an optical recording film formed over said hard plastic substrate;
- and
- a UV-cured resin layer formed over said optical recording film, said UV-cured resin being formed by curing a UV-curable resin composition which comprises:
- a) 15 to 85% by weight of a first ingredient of an acrylate and/or a methacrylate having at least three functionalities;
- b) 15 to 70% by weight of a second ingredient of a compound having a linear structure and a molecular weight of at least 300 and a molecular weight of at least 150 per ethlenically unsaturated bond;
- c) at least 0.3% by weight of a photopolymerization initiator;
- and
- d) not more than 40% by weight of a third ingredient of an acrylate and/or methacrylate having two functionalities;
- said UV-curable resin composition containing as an ingredient substantially no acrylate or methacrylate having one functionality, wherein said UV-cured resin layer has an acid value of not more than 1.5 and a softening point not lower than 50.degree. C.
A process for manufacturing an optical recording medium, said process comprising the steps of:
- forming an optical recording film over a hard plastic substrate;
- coating a UV-curable resin composition over said optical recording film to form a UV-curable resin layer, said UV-curable resin composition comprising;
- a) 15 to 85% by weight of a first ingredient of an acrylate and/or a methacrylate having at least three functionalities;
- b) 15 to 70% by weight of a second ingredient of a compound having a linear structure and a molecular weight of at least 300 and a molecular weight of at least 150 per ethlenically unsaturated bond;
- c) at least 0.3% by weight of a photopolymerization initiator;
- and
- d) not more than 40% by weight of a third ingredient of an acrylate and/or methacrylate having two functionalities;
- said UV-curable resin composition containing as an ingredient substantially no acrylate or methacrylate having one functionality, said UV-curable resin composition having an acid value of not more than 1.5 and a viscosity of 10 to 5,000 cps at 25.degree. C.;
- and irradiating said UV-curable resin layer with UV rays to form said UV-cured resin layer.
Dependencies are inferred from the claim text.