JPH0612579B2 - Optical information recording medium - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical information recording medium in which a curing undercoat layer of a photocurable resin is provided on a substrate.

[Prior art]

Conventionally, the injection method and the photopolymerization method have been used as the method for forming the uneven information track on the substrate.
(See Philips tech. Rev. 40, pp. 298-309 (1982)). However, the optical memory disk substrate manufactured by the injection method has a large amount of birefringence, and the light fluctuates to cause a lot of noise. Further, since the solvent resistance is not good, the pregroup may be lost when the reflective layer, the recording layer and the protective layer are formed on the information track by the wet coating method. In addition, when a recording material using metallic reflection of dye is used, there is a drawback in that the reflectance decreases due to penetration even before the pregroup disappears, which imposes a heavy load on focusing, tracking, and signal reading of the recording / reproducing apparatus. is there.

On the other hand, the formation of a pregroup by a photopolymerization method using a base polymer, a diluent, a photoinitiator, etc. improves the above-mentioned birefringence and solvent resistance but does not affect the storage stability of the recording material thin film. give. In particular, there are drawbacks such that pinholes are generated due to photodegradation, heat degradation, etc., and reflectance and light absorption are reduced.

〔Purpose〕

The present invention has been made in view of the above-mentioned conventional technique, and its object is to eliminate the drawbacks of the conventional technique and to have a large adhesive force to a substrate, and to manufacture the concave-convex pattern forming mold (stamper) by accurate transfer. Alternatively, the uneven pattern formed on the surface of the undercoat layer has good solvent resistance, and even after the dye thin film is formed thereon, there are effective unevenness, and the light having high reflectance and good storage stability. It is to provide an information recording medium.

〔Constitution〕

The feature of the present invention is that the formula on the substrate (In the formula, R ₁ represents hydrogen or a methyl group, and R ₂ represents C ₂
-C ₄ represents an alkylene group and n is provided with a subbing layer formed by curing with actinic radiation of 2-functional acrylate or methacrylate monomer represented by the number of 1 to 20 with an average value of the number of moles) At the same time, a pre-group or pre-format (hereinafter collectively referred to as "concave pattern" for convenience) made of the above-mentioned monomer is formed on the surface of the undercoat layer, and then a recording layer is provided thereon.

The concavo-convex pattern is an accurate transfer of the original shape existing in the pattern forming die (stamper), and usually has a structure in which convex portions located at a high level and concave portions located at a low level are alternately present. The height of the unevenness is usually λ / 10 to λ
It has been adjusted to / 4.

The subbing layer in the present invention comprises an acrylate or methacrylate monomer of the above formula and a photopolymerization initiator, and if necessary, further cures a photocurable composition containing other components such as a sensitizer and a storage stabilizer by irradiation with actinic rays. Can be formed. Representative examples of the above monomers include ethylene glycol diacrylate, neopentyl glycol diacrylate, isopropylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, and the corresponding dimethacrylate. However, other than these diacrylates and dimethacrylates, other monoacrylates, monomethacrylates, diacrylates, dimethacrylates, triacrylates, trimethacrylates, mothraacrylates, tetramethacrylates, etc. may be mixed and used. As the photopolymerization initiator, conventionally known ones can be preferably used, and typical examples thereof are as follows.

Acetophenone, 2,2-diethoxyacetophenone,
p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, p, p'-dichlorobenzophenone,
p, p'-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, denzoin isopropyl ether, benzoin n-propyl ether, benzoin isobutyl ether, benzoin n-butyl ether, benzyl methyl ketal, tetramethyl Thiuram monosulfide, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, azobisisobutyronitrile, benzoin peroxide, di-tert.
-Butyl peroxide, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxy-isobutylphenone, dibenzosuberone, diethylthioxanthone.

These photopolymerization initiators are used in the range of 0.05 to 10 parts by weight with respect to 100 parts by weight of the above-mentioned monomer, but preferably,
It is in the range of 0.2 to 5 parts by weight.

Further, as the sensitizer, an amine compound, a urea compound, a sulfur compound, a titryl compound, a phosphorus compound and a nitrogen compound can be used. These sensitizers are preferably contained in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the above monomers. Storage stabilizers include quaternary ammonium chloride, diethylhydroxyamine, cyclic amides, nitrile compounds, substituted urea, benzothiazole, 4-amino-2,2,6,6-tetramethylpiperidine, bis- (1,2,2 2,6,6-pentamethyl-4
-Piperidine) sebacate, organic acids such as lactic acid, oxalic acid, citric acid, tartaric acid, benzoic acid, and hadroquinone can be used, and the amount is 0.0001 to 2 parts by weight relative to 100 parts by weight of the above monomer. preferable.

The recording layer in the present invention comprises a cyanine dye or a merocyanine dye having the formula shown below, and may further contain a binder, a stabilizer (transition metal complex, etc.) and the like, if necessary.

Cyanine dyeOrHowever, R₁And R₂Is a substituted or unsubstituted alkyl
Group, substituted or unsubstituted aralkyl group or alkene group
Represents a nyl group, Z₁And Z₂Is a substituted or unsubstituted complex
A group of atoms required to complete the ring is shown as Z₃Is a replacement
Is an atom required to complete an unsubstituted 5- or 6-membered ring
And a 5-membered ring or a 6-membered ring is an aromatic ring
R may be condensed.₃Is hydrogen atom or halogen atom
Indicates a child, R_FourAnd R_FiveIs a hydrogen atom, a halogen atom,
Droxy, carboxyl, alkyl, substituted or
Represents an unsubstituted aryl group or an acyloxy group, X
Represents an acid anion, and m and n are 0 or
Is 1.

Merocyanine dye However, And the benzene ring and naphthyl ring of the above formula may be substituted, Is And n represents 1 or 2.

The recording layer is preferably formed by applying a solution in which a predetermined dye is dissolved in a suitable organic solvent such as dichloroethane, onto the undercoat layer. Of course, it can also be formed by vapor deposition, sputtering or the like. The thickness of the recording layer is 10 to 1000 nm, preferably 20 to 70 nm. The thickness of the undercoat layer is in the range of 1 to 200 μm, preferably 10 to 100 μm.

The substrate used in the present invention generally needs to be one that transmits actinic rays (for example, ultraviolet rays, light, etc.) that cure the photocurable composition. Specifically, a glass plate, a plastic plate or the like can be used. As the material of the plastic plate, acrylic resin, polystyrene resin, polycarbonate resin, cellulose resin, cellulose triacetate, polystyrene terephthalate, and mixtures and copolymers thereof are used. Among these, a desirable substrate is preferably a substrate containing polymethacrylate resin or polycarbonate resin as a main component.

Next, a method for transferring an uneven pattern onto the undercoat layer using the photocurable composition of the present invention will be described with reference to the drawings.

First, as shown in FIG. 1, a mold (stamper) 2 having an uneven pattern 1 to be transferred on its surface is prepared.
The material of this mold is nickel, chromium or alloys thereof, and the surface is hardened if necessary.
Next, as shown in FIG. 2, a layer 3 of the photocurable composition is applied onto the mold 2, a substrate 4 is superposed on the layer 3, and then an actinic ray is irradiated to cure the photopolymerizable layer 3. Let As a light source of actinic rays, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a cannon lamp, a metal halide lamp, a carbon arc, an ultraviolet fluorescent lamp, etc. are used. After irradiation with actinic rays, the mold 2 is peeled off as shown in FIG. 3, and the photo-curable layer 3 ′ (undercoat layer) to which the concave-convex pattern 1 of the mold 2 has been accurately transferred remains on the substrate 4. Such a transfer method is achieved by using the photopolymerizable composition of the present invention, and the adhesive force A between the photocurable composition and the substrate and the adhesive force B between the photocurable composition and the mold are A> This is because it becomes B. Further, in order to further improve the relationship of the adhesive force as described above, surface treatment, for example, coating an undercoat layer on the substrate (for example, a precoat layer such as a silane coupling agent, an acrylic hard coat layer, etc.), a corona discharge treatment, Flame treatment, ultraviolet treatment, high-frequency irradiation treatment, glow discharge irradiation treatment, active plasma irradiation treatment, laser beam irradiation treatment and the like can be performed.

〔Example〕

Hereinafter, the present invention will be further described with reference to examples together with comparative examples, but the present invention is not limited to these examples. The composition ratios in each example are all parts by weight unless otherwise specified.

Example 1 Tripropylene glycol 100 parts Diacrylate 2,2-dimethoxy-2-f 3 parts Enylacetophenone The above components were mixed well to prepare a photopolymerizable liquid. This solution was dropped on a nickel stamper having an uneven pattern on the surface, and a polymethylmethacrylate substrate (with a cured film formed on it-Acrylite AR made by Mitsubishi Rayon) was overlaid and then a high-pressure mercury lamp with an intensity of 80 W / cm was used. UV light for 1 minute. Then, when the substrate was peeled from the nickel stamper, the concavo-convex pattern was accurately transferred onto the substrate. At this time, the force required for peeling is 0.2 kg / cm ^2, whereas adhesion to the substrate of the photocurable layer was 1.1 kg / cm ^2. The recording medium thus prepared was immersed in isopropyl alcohol for 15 minutes and then dried, but the unevenness transferred from the stamper did not change, and the recording medium was dried with 2,2-dichloroethane at 30%.
After soaking for a second and then dried, no change was observed in the unevenness.

Furthermore, the expression on the uneven pattern Of a 0.7% 2,2-dichloroethane solution of the above dye at 1000 rpm
The results are shown in the table below, after spin-coating with, drying, and testing under tungsten light at 150 ° C. and 54,000 lux.

Example 2 100 parts of ethylene glycol diacrylate 0.5 parts of diethyl thioxanthone 0.5 parts A recording medium was prepared and evaluated in the same manner as in Example 1 except that the above components were well mixed to prepare a photopolymerizable liquid.

Example 3 Triethylene glycol 100 parts Diacrylate Chlorthioxanthone 0.5 part A recording medium was prepared and evaluated in the same manner as in Example 1 except that the above components were well mixed to prepare a photopolymerizable liquid.

Comparative Example 1 Bis (acryloxyetoki 100 parts ci) Bisphenol A 2,2-dimethoxy-2-phenyl 3 parts phenylacetophenone Using a photopolymerizable liquid prepared by thoroughly mixing the above components, in the same manner as in Example 1. A recording medium was produced by transfer and evaluated. The peeling takes the force of 0.3 kg / cm ^2, adhesion to the substrate of the photocurable layer was 1.4 kg / cm ^2. The solvent resistance was the same as that of Example 1, but the deterioration test showed accelerated deterioration as shown in the table below.

Comparative example 2 Using a photopolymerizable liquid prepared by thoroughly mixing the above components, an attempt was made to perform transfer in the same manner as in Example 1, but cohesive peeling occurred and transfer could not be performed.

[Effect] According to the present invention, the use of the photocurable composition improves the releasability from the stamper of the substrate on which the uneven pattern is formed, so that the uneven pattern is accurately transferred to the undercoat layer,
Further, the uneven pattern formed on the surface of the undercoat layer has good solvent resistance, and since effective unevenness exists even after the dye thin film is formed thereon, the reflectance is high and the groove signal is not deteriorated. It is possible to provide an optical information recording medium that is suppressed and has good storage stability.

[Brief description of drawings]

1 to 3 are schematic views for explaining the method of manufacturing the optical information recording medium of the present invention. 1 ... uneven pattern, 2 ... type, 3 ... photocurable composition layer, 3 '... photocurable layer (undercoat layer), 4 ... substrate.

Claims (1)

[Claims] 1. An information recording medium comprising a substrate on which an undercoating layer having a concavo-convex pattern is provided, and a recording layer is formed on the undercoating layer. (In the formula, R ₁ represents hydrogen or a methyl group, and R ₂ represents C ₂
-C ₄ represents an alkylene group and n is formed by curing with actinic radiation of difunctional acrylates or wound Tari rate monomers represented by the average value of the molar number of addition represents the number of 1 to 20) and said recording layer Contains an cyanine dye or a merocyanine dye.