Optical disc and material for substrate thereof
AssigneesSanyo Electric Co., Ltd., Mitsui Chemicals, Inc.
InventorsMinoru Ono, Tadahiro Miyazaki, Masahiro Higuchi, Yoshiaki Maeno, Takashi Arai, Masahiro Sugi
Life of this patent
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Abstract
An optical disc 10 includes a substrate. The substrate is formed by mixing polymethyl methacrylate and a polylactic acid-based resin composition. The polylactic acid-based resin composition contains polylactic acid-based resin in which the content of lactide is reduced to 1,000 ppm or less, and a mold release agent of 0.16 to 0.32 phr. The weight ratio of the polylactic acid-based resin to the polymethyl methacrylate is 70:30 to 50:50.
Claims16
An optical disc comprising:
- a substrate with a signal recording surface formed on one side and made of polylactic acid-based resin composition having polylactic acid-based resin with a mold release agent added,
- wherein the content of lactide in said polylactic acid-based resin is 1,000 ppm or less and the amount of said added mold release agent is 0.16 to 0.32 phr, and
- wherein a thickness of the substrate with a refractive index n meets (1.58/n)×1.2.
An optical disc comprising:
- a substrate with a signal recording surface formed on one side and made of transparent resin having an alloy of polylactic acid-based resin and alkyl (meth)acrylate-based resin,
- wherein the weight ratio of said polylactic acid-based resin to said alkyl (meth)acrylate-based resin is 70:30 to 50:50, and
- wherein the difference in refractive index between the alkyl(meth)acrylate-based resin and the polylactic acid-based resin to be alloyed is 0.05 or less.
An optical disc comprising:
- two substrates with a signal recording surface formed on one side and made of transparent plant-derived resin, said two substrates having said signal recording surfaces opposed to each other, at least one of said two substrates being formed by transparent resin in which polylactic acid-based resin and alkyl (meth)acrylate-based resin are alloyed;
- and reflective films formed on said signal recording surfaces of said two substrates by either a plant-derived material or a material existing in nature, wherein a thickness of the substrate with a refractive index n meets (1.58/n)×1.2.
An optical disc comprising:
- a first substrate with a signal recording surface formed on one side and made of transparent plant-derived resin;
- a semipermeable reflective film formed on said signal recording surface of said first substrate by either a plant-derived material or a material existing in nature;
- an adhesive layer formed by transparent resin on said semipermeable reflective film;
- a second substrate with a signal recording surface formed on one side and made of plant-derived resin on said adhesive layer;
- and
- a reflective film formed on said signal recording surface of said second substrate by either a plant-derived material or a material existing in nature,
- wherein at least one of said first substrate and said second substrate is formed by transparent resin in which polylactic acid-based resin and alkyl (meth)acrylate-based resin are alloyed, and
- wherein the difference in refractive index between the alkyl(meth)acrylate-based resin and the polylactic acid-based resin to be alloyed is 0.05 or less.
A material for a substrate of an optical disc with a signal recording surface formed on one side, the material being made of a polylactic acid-based resin composition in which a mold release agent is added to polylactic acid-based resin, wherein the content of lactide in said polylactic acid-based resin is set at 1,000 ppm or less and the amount of said added mold release agent is set at 0.16 to 0.32 phr, and wherein a thickness of the substrate with a refractive index n meets (1.58/n)×1.2.
Dependencies are inferred from the claim text.