Process for producing plastic information-recording medium and resin composition used therefor

Claim 2

A process for producing a plastic information-recording medium, characterized by casting a light- or radiation-curable resin composition into a cavity formed by a stamper having an information pattern forming surface thereon and a releasable plate having a smooth surface thereon, at least one of the stamper and the releasable plate being transparent, irradiating a light or radiation through at least one of transparent stamper and transparent releasable plate to cure the resin composition, and removing the stamper and the releasable plate.

Claim 3

A process according to Claim 1, wherein both the stamper and the releasable plate are transparent and the irradiation of a light or radiation is conducted from both sides at the same time.

Claim 4

A process according to Claim 2, wherein the light- or radiation-curable resin composition comprises (i) a compound (I) having 4 or more acryl or methacryl groups in one molecule and a viscosity of 3000 cps or less at 25°C, (ii) a compound (II) represented by the formula: wherein R 1 is hydrogen or a methyl group; R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, or a group of the formula: or (̵-E-CH2)̵ m in which m is an integer of 3 to 10, (iii) a compound (III) of the formula: wherein R 1 is as defined above; and R 4 is a hydrocarbon group having 6 to 16 carbon atoms, and (iv) a photopolymerization initiator in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of the compounds (I), (II) and (III), and the compounds (I), (II) and (III) being used in amounts in the closed area of lines A-B-C-D-E-A in the triangular diagram of Fig. 1, wherein individual points A, B, C, D and E have the following values in parcents by weight:

Claim 5

A process according to Claim 1, wherein the irradiation of the light or radiation is conducted from one side through the transparent stamper or the transparent releasable plate and the light-or radiation-curable resin composition comprises (i) a compound (I) having 4 or more acryl or methacryl groups in one molecule and a viscosity of 3000 cps or less at 25°C, (ii) a compound (II) represented by the formula: wherein R 1 is hydrogen or a methyl group; R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, or a group of the formula: (̵CH 2 )̵ m in which m is an integer of 3 to 1 0 , (iii) a compound (III) of the formula: wherein R 1 is as defined above; and R 4 is a hydrocarbon group having 6 to 16 carbon atoms, and (iv) a photopolymerization intiator in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of the compounds (I), (II) and (III), and the compounds (I)', (II) and (III) being used in amounts in the closed area of lines A-B-C-D-E-A in the triangular diagram of Fig. 1, wherein individual points A, B, C, D and E have the following values in percents by weight:

Claim 6

A process according to Claim 1, 2, or 4, wherein the light or radiation is ultraviolet light.

Claim 7

A process according to Claim 3 or 4, wherein the compound (I) is at least one member selected from the group consisting of pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, dipentaerythitol derivative hexaacrylate and dipentaerythitol derivative hexamethacrylate.

Claim 8

A process according to Claim 3 or 4, wherein the compound (II) is at least one member selected from the group consisting of a reaction product of 1 mole of l,l'-methylene- bis(4-isocyanatobenzene) and 2 moles of 2-hydroxyethyl acrylate, a reaction product of 1 mole of l,l'-methylene- bis(4-isocyanatobenzene) and 2 moles of 2-hydroxyethyl methacrylate, a reaction product of 1 mole of l,l'-methylene- bis(4-isocyanatocyclohexane} and 2 moles of 2-hydroxyethyl acrylate, a reaction product of 1 mole of 1, 1'-methylene- bis(4-isocyanatocyclohexane) and 2 moles of 2-hydroxyethyl methacrylate, a reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxyethyl acrylate, a reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxyethyl methacrylate, a reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxypropyl acrylate, a reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxypropyl methacrylate, a reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxybutyl acrylate, a reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxybutyl methacrylate, a reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxy-3-phenoxypropyl acrylate, and a reaction product of 1 mole of isophorone diisocyanate and 2 moles of 2-hydroxy-3-phenoxypropyl methacrylate.

Claim 9

A process accrding to Claim 3, or 4, wherein the compound (III) is at least one member selected from the group consisting of cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, tricyclodecanyl acrylate and tricyclodecanyl methacrylate.

Claim 10

A light- or radiation-curable resin composition for producing a plastic information-recording medium comprising a resin component and a photopolymerization initiator, characterized in that said resin component comprises (i) a compound (I) having 4 or more acryl or methacryl groups in one molecule and a viscosity of 3000 cps or less at 25°C, (ii) a compound (II) represented by the formula: wherein R 1 is hydrogen or a methyl group; R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, or a group of the formula: or (̵ CH 2 )̵ m in which m is an integer of 3 to 10, (iii) a compound (III) of the formula: wherein R 1 is as defined above; and R 4 is a hydrocarbon group having 6 to 16 carbon atoms, and (iv) a photopolymerization initiator in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of the compounds (I), (II) and (III), and the compounds (I), (II) and (III) being used in amounts in the closed area of lines A-B-C-D-E-A in the triangular diagram of Fig. 1, wherein individual points A, B, C, D and E have the following values in percents by weight:

Claim 11

A light- or radiation-curable resin composition for producing a plastic information-recording medium comprising a resin component and a photopolymerization initiator, characterized in that said resin component comprises (i) a compound (I) having 4 or more acryl or methacryl groups in one molecule and a viscosity of 3000 cps or less at 25°C, (ii) a compound (II) represented by the formula: wherein R 1 is hydrogen or a methyl group; R 2 is hydrogen, an alkyl group having 1 to 5 carbon atoms, or a group of the formula: or (̵ CH 2 )̵ m in which m is an integer of 3 to 10, (iii) a compound (III) of the formula: wherein R 1 is as defined above; and R 4 is a hydrocarbon group having 6 to 16 carbon atoms, and (iv) a photopolymerization initiator in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of the compounds (I), (II) and (III), and the compounds (I), (II) and (III) being used in amounts in the closed area of lines A-B-C-D-E-A in the triangular diagram of Fig. 1, wherein individual points A, B, C, D and E have the following values in percents by weight:

Claim 12

A plastic information-recording medium (3-3) produced by the process of Claim 1.