JP3328838B2 - Optical information recording medium - Google Patents

Description

The present invention relates to an improved optical information recording medium that can be used in the optical recording field.

[Problems to be solved by conventional technology and invention]

Providing a recording layer by spinner coating in an organic dye-based optical disk is a well-known technique. Usually, the two recording media thus obtained are laminated to form an air sandwich structure. At this time, a light-curing adhesive is used as the adhesive because of high productivity. As a problem at this time, there is a deterioration in the recording material during storage due to the uncured monomer due to a decrease in the adhesive strength due to the dye applied to the adhesive portion and a decrease in the degree of curing of the adhesive.

In order to solve the above problem, a method of wiping a dye adhered to an adhesive portion has been proposed (JP-A-63-47194). In order to improve the above problem, a dye having a high dye solubility has been proposed. Use of an adhesive (JP-A-60-185234,
61-142545, 61-190736, 61-190738, 62
No. 141141) has been proposed.

However, in the former method, productivity is impaired,
At present, the latter method has not been developed to achieve both the effect on the adhesive strength and the effect on the storage stability.

The present invention solves the drawbacks of the prior art described above, and does not require a dye wiping step, maintains high productivity of sealing with a light-curable adhesive, and cures the adhesive even when the dye is attached. It is an object of the present invention to provide an optical information recording medium capable of increasing the degree of adhesion and consequently improving the adhesive strength and the storage stability of the recording material at the same time.

[Means for solving the problem]

The above object is achieved by including at least one compound of the following general formula (I) in a recording layer of an optical information recording medium.

"General formula (I): (In the above formula, R ₁ and R ₂ both represent a substituted or unsubstituted alkyl group, aralkyl group or alkenyl group. Z ₁ and
Z ₂ represents a group of atoms necessary to complete a substituted or unsubstituted heterocyclic ring. R ₄ and R ₅ represent a hydrogen atom, a halogen atom, a hydroxy group, a carboxyl group, an alkyl group, a substituted or unsubstituted aryl group or an acyloxy group. R ₆ is
It represents a substituted or unsubstituted aryl group. R ₇ represents an alkyl group having 1 to 18 carbon atoms. l, m and n are 0 or 1
It is. The dye represented by the general formula (I) has optical characteristics (m, k) as a recording material for an optical information recording medium, and at the same time, is a highly sensitive initiator (sensitizer) for a radical polymerization type photopolymer. But also. The reaction process is shown below.

[In the above, R. is a radical polymerization initiator.

¹ Dye ^* : excited singlet dye, Dy: dye radical, → (R ₁ ) ₃ R ₂ : radical, R ₂ .: Alkyl radical. It is known that by counter-ionizing the borate-based initiator and the cationic dye in this way, it has the function of a highly sensitive initiator and at the same time exhibits excellent properties as a dye for laser recording as a cationic dye. The object of the present invention is achieved by using a cyanine dye which is used.

The optical information recording medium of the present invention is basically constituted by providing a recording layer containing a dye represented by the above general formula on at least a part of a recording material on a substrate. An undercoat layer may be provided between the recording layer and the recording layer, or a protective layer may be provided on the recording layer. Further, the pair of recording media thus configured may be formed into an air sandwich structure in which the recording layer is inwardly sealed with another substrate through a space, or an adhesive sandwich bonded through a protective layer (lamination). ) It may be structured.

Next, the material constituting the optical information recording medium of the present invention and the required characteristics of each layer will be specifically described.

(1) Substrate The required characteristics of the substrate are that it must be transparent to the laser beam used only when recording / reproducing from the substrate side.
When performed from the recording side, it is not necessary to be transparent. As the substrate material, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, glass, ceramic, metal or the like can be used.

Note that a preformat of an address signal or a pregroove of a guide groove may be formed on the surface of the substrate.

(2) Recording Layer The recording layer is capable of causing some optical change by laser beam irradiation and recording information by the change. At least a part of the recording layer contains at least one dye of the compound of the formula (I). ing.

In the recording layer of the recording medium of the present invention, for improving recording characteristics and stability, if necessary, other dyes, for example,
Phthalocyanine-based, tetrahydrocholine-based, dioxazine-based, triphenothiazine-based, phenanthrene-based, anthraquinone (indanthrene) -based, xanthene-based, triphenylmethane-based, triphenylamine-based, azulene-based dye, metal or metal compound, for example, In, Sn, Te, Bi, A
l, Se, TeO ₂ , SnO, Ag, Cu and the like may be mixed and dispersed, or may be laminated. In addition, the recording layer may contain a polymer material or a low molecular material, a storage stabilizer (metal complex, phenolic compound), a dispersant, a flame retardant, a lubricant, a plasticizer, and the like. The thickness of the recording layer is 100 to 10 μm, preferably 200 to 2 μm. As a method for forming the recording layer, a solvent coating method such as dip coating, spray coating, spinner coating, blade coating, roller coating, curtain coating and the like can be used in addition to vapor deposition, CVD, and sputtering.

(3) Undercoat layer The undercoat layer comprises (a) an improvement in adhesiveness, (b) a barrier against water or gas, (c) an improvement in storage stability of the recording layer, and (d) an improvement in reflectance, and (e). ) Protection of the substrate from solvents,
(F) It is used for the purpose of forming a pre-groove. For the purpose of (a), polymer materials, for example, various polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents are used. For the purposes of (b) and (c), inorganic compounds other than the above-mentioned polymer materials, for example, SiO ₂ , MgF ₂ , SiO, TiO ₂ , Zn
Metals or metalloids such as O, TiN, SiN, for example, Zn, Cu, S, N
i, Cr, Ge, Se, Au, Ag, Al and the like can be used. Further, for the purpose of (d), a metal, for example, Al, Ag or the like, or an organic thin film having a metallic luster, for example, methine dye,
A xanthene dye or the like can be used, and for the purposes of (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used.

(4) Protective layer The protective layer (a) protects the recording layer from scratches, dust, dirt, etc., (b) improves the storage stability of the recording layer, and (c)
It is used for the purpose of improving the reflectance. For these purposes, the materials shown in the undercoat layer can be used.

(5) Sealing adhesive A photo-curing adhesive is used as the sealing adhesive. Examples of such an adhesive include (a) polyester acrylate, (b) epoxy acrylate, and (c) A composition comprising a photopolymerizable polymer classified as polyurethane acrylate, (d) polyether acrylate, a photopolymerizable monomer for adapting to the use of the cured product, and a photoinitiator for initiating polymerization is used. .

In the present invention, the undercoat layer and the protective layer may contain a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like, as in the case of the recording layer. . Further, the compound represented by the general formula (I) can be contained in the undercoat layer or the protective layer.

Next, specific examples of the compounds that can be preferably used in the present invention will be shown.

Compound example [Examples] Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited to only these Examples.

(Example 1) On a substrate provided with a spiral guide groove having a depth of 900 mm, a half-value width of 0.4 µm, and a pitch of 1.6 µm on a 1.2-mm-thick polymethyl methacrylate (PMMA) plate (130 mm in diameter) using an acrylic photopolymer. Then, a 1,2-dichloroethane solution of the compound No. 2 was spin-coated to form a recording layer having a thickness of 800 mm, and then two substrates with a recording layer were separated by a spacer without wiping the outer peripheral dye. (Thickness 5mm, inner diameter 11m
m, inner diameter 30 mm, outer diameter 125 mm, outer diameter 130 mm) with adhesive (spirourethane / 1,6-hexanediol diacrylate / caprolactone-modified 2-hydroxyethyl acrylate = 4/3/3 + initiator benzyl dimethyl) Ketal 3
wt%) to form a recording medium.

(Example 2) A recording medium was obtained in the same manner as in Example 1, except that Compound No. 5 was used instead of Compound No. 2.

(Example 3) A recording medium was obtained in the same manner as in Example 1, except that Compound No. 7 was used instead of Compound No. 2.

(Example 4) In Example 1, the following dye (I) was added to Compound No. 2 described above.
Were mixed in the same manner except that 1 was mixed at a weight ratio of 1: 1.

(Example 5) In Example 2, the following dye (II) was added to Compound No. 5 described above.
Were mixed in the same manner except that the mixture was mixed at a weight ratio of 2: 1.

(Example 6) In Example 3, the following compound (II)
A recording medium was obtained in the same manner except that I) was mixed at a weight ratio of 100: 15.

(Example 7) A recording medium was obtained in the same manner as in Example 6, except that the above compound (III) was changed to the following compound (IV).

Comparative Example 1 A recording medium was obtained in the same manner as in Example 1, except that ClO ₄ was used as the counter ion.

Comparative Example 2 A recording medium was obtained in the same manner as in Example 3, except that ClO ₄ was used as the counter ion.

Each recording medium prepared as described above was subjected to an adhesive strength test and a storage test. The results are shown in Table-6. The storage test was performed at 60 ° C.-90% for 2000 hours.

As can be seen from Table 6, it was confirmed that the recording medium according to each example of the present invention was significantly superior in all of the adhesive strength, the optical density change, and the jitter change as compared with the comparative example.

[Effects of the Invention] According to the present invention, since the above-mentioned compound is used in the recording layer, the degree of curing of the adhesive is promoted even in the state where the dye is adhered, and the adhesive strength and storage stability can be improved.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-47590 (JP, A) JP-A-1-208191 (JP, A) JP-A-2-572 (JP, A) JP-A-2-47 147286 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/26 G11B 7/24 516

Claims (1)

(57) [Claims] 1. An optical information recording medium comprising a recording layer containing an organic dye provided directly or via an undercoat layer on a substrate, and a protective layer provided thereon if necessary. An optical information recording medium comprising at least one compound of the following general formula (I). General formula (I): (In the above formula, .Z ₁ and Z ₂ indicate the R ₁ and R ₂ are both a substituted or unsubstituted alkyl group, .R ₄ and represents an atomic group necessary for forming a heterocyclic ring substituted or unsubstituted R ₅ represents a hydrogen atom, a halogen atom, a hydroxy group, a carboxyl group, an alkyl group, a substituted or unsubstituted aryl group or an acyloxy group, R ₆ represents a substituted or unsubstituted aryl group, and R ₇ represents And represents an alkyl group having 1 to 18 carbon atoms.
l, m and n are 0 or 1. )