JPH039881A - Optical data recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical data recording medium good in productivity and having high recording reproduction sensitivity and good storage stability by providing a recording layer containing a specific compound. CONSTITUTION:The recording layer of an optical data recording medium may be provided to both surfaces of a substrate or only to the single surface thereof. A compound represented by formula (1) (wherein each of R1, R2, R3, R4, R5, R6, R7 and R8 is a hydrogen atom or an alkyl group and the total number of carbon atoms of R1 to R8 is 4 or more. M is 2H, a metal, metal oxide or metal halide) is dissolved in an org. solvent and applied to the substrate to form the recording layer and contained in the recording layer usually in an amount of 10-100%, pref., 50-100%. The recording on the recording layer is performed by applying laser beam, pref., semiconductor laser beam converged to about 1mum to the recording layer to generate thermal deformation due to decomposition, evaporation, sublimination or melting in the recording layer by the absorption of laser energy. The reproduction of recording can be performed by reading the change of reflectivity in a part generating thermal deformation by laser beam and a non-deformed part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical information recording medium. More specifically, the present invention relates to an optical information recording medium on which recording and reproduction can be performed by causing a state change using a laser, particularly a semiconductor laser.

[Prior Art] Conventionally, optical information recording media have been known which are provided with an information recording layer made of a phthalocyanine compound as an optical information recording medium. (For example, JP-A-58-56892 and JP-A-64-4390) [Problems to be solved by the invention] However, an optical information recording medium with good productivity, high recording/reproduction sensitivity, and good storage stability has not yet been developed. It has not been.

[Means for Solving the Problems] The present inventor has arrived at the present invention as a result of intensive studies on optical information recording media that have good productivity, high recording/reproduction sensitivity, and good storage stability.

That is, the present invention is based on the general formula (In the formula, Rt, R2, R3, R4, R5+R6.

R? , R8 is a hydrogen atom or an alkyl group, R1
t R2t R31R41R51R6t R71R8
The total number of carbon atoms is 4 or more. M is a 2H1 metal, metal oxide or metal halide. ) is an optical information recording medium characterized by having a recording layer containing a compound represented by:

- R,, R2, R3, R4 at maximum (1).

The alkyl group represented by R6, R6, R, and R8 includes a tertiary carbon-containing alkyl group (t-butyl, t-amyl, t-hexyl, 2,2-dimethylpropyl group, etc.)
and other alkyl groups, such as primary or secondary carbon-containing alkyl groups having 1 to 18 carbon atoms (methyl, ethyl, isopropyl, n-butyl, i-butyl, S-butyl, n-
amyl, i-amyl, S-amyl, n-hexyl, i-
hexyl, n-heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, octadecyl, etc.)
can be given.

Preferably at least one of R1, R2, R3, R4, Rs, R6, R7 and R8 is a tertiary carbon-containing alkyl group, and particularly preferably four are tertiary carbon-containing alkyl groups.

A preferred tertiary carbon-containing alkyl group is a t-butyl group.

R=, Rx, R3, R4, Rs, Rb,
The total number of carbon atoms in R7 and R8 is preferably 12 to 2.
It is 4.

M metals (including metalloids) are elements of groups ■ to ■ of the periodic table of elements, such as group I (Cu, Ag, Au, etc.),
Group ■ (Mg, Zn, etc.), Group ■ (AI, In, lanthanum series elements, actinium series elements, etc.), Group ■ (Ti,
Sn, Pb, etc.), V group (V, Nb etc.), ■ group (Mo
, W, etc.), ■ group (Mn, Tc etc.) and ■ group (Fe
,C.

, Ni, Pd, Pt, etc.).

As the metal oxide, oxides of the above metals, such as Ti
Examples include O and ■0. Examples of metal halides include chlorides (AICI, TiCl2, etc.) and bromides (AIBr, TiBr2, etc.) of the above metals.

Among M, preferable ones are Mg, AI, Ti, V, C01
These are metals such as Cu, In, Sn, and Pb, and their oxides and chlorides.

Examples of the compound of general formula (1) include compounds having groups as shown in Table 1.

Table 1 *Bu; Butyl group Am Niamyl group-a Two or more compounds of formula (1) can also be used in combination.

The compound of general formula (1) is obtained by obtaining an alkylated 6,7-dibromoquinoquinol compound from 4,5-dibromo-O-phenylenediamine and a glyoxyl or dicthone compound, and reacting it with cupric cyanide. The alkylated 6,7-dicyatoquinoxaline compound obtained by this method can be used to synthesize a phthalocyanine compound from phthalonitrile and a metal or a metal compound.

The compound of general formula (1) may contain other dyes, such as phthalocyanine-based, anthraquinone-based, cyanine-based, squarylium-based, azulene-based, tetrahydrocholine-based, triphenylmethane-based, biryllium-based, dioxazine-based dyes, or metals or metal compounds. etc., for example Te, Bi,
Al, Se, In, Sn, As, Cd, TeO2, Sn
It may be mixed and dispersed or laminated with O or the like.

- The maximum compound (1) can form a recording layer by dissolving it in an organic solvent.

Solvents for dissolution include general organic solvents such as ether, halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride, dichloroethane, etc.), ketones (acetone, methyl ethyl ketone, cyclohexanone, etc.)
, nitriles (acetonitrile, benzonitrile, etc.),
Esters (ethyl acetate, isopropyl acetate, etc.), aromatic hydrocarbons (toluene, xylene, etc.), aliphatic hydrocarbons (n-hexane, n-octane, etc.), alcohols (
Methanol, ethanol, impropatol, butanol, amyl alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, acetol, etc.) and mixed solvents of two or more of these can be used.

This solvent is preferably a solvent that does not attack the substrate material used in the recording medium described later.

It is also possible to optionally add binders such as polystyrene, polyvinyl acetate, polyvinyl alcohol or polyvinylpyrrolidone.

Furthermore, it can be used as an additive for stabilizers, dispersants, adhesives, lubricants, antistatic agents, surfactants, plasticizers, flame retardants, etc. for the purpose of improving properties.

Examples of these formulations are shown below.

Compound 3-20% Solvent 80-97% Binder (11-3% Additive 0.1-3%) The recording medium is obtained by applying the formulation to the substrate material.

Examples of substrate materials used for recording media include glass and plastics. Examples of plastics include acrylic resin, methacrylic resin, polycarbonate resin, vinyl chloride resin, vinyl acetate resin, polyester resin, polyethylene resin, polypropylene resin, polyamide resin, polystyrene resin, and epoxy resin.

Application methods include coating methods.

Specifically, there are a method in which the above-mentioned mixed solution is brought into contact with a substrate that has been made normal in advance, and then the substrate is rotated to remove excess solution, and a method in which the mixed solution is allowed to flow down while rotating the substrate.

The solvent of the solution can be dried by air drying or by heating.

In addition to coating, methods such as vacuum evaporation, sputtering, and ion blating can also be used, but these methods require complicated operations and are inferior in terms of productivity, so so-called coating methods are preferred. .

The recording layer of the optical information recording medium of the present invention may be provided on both sides of the substrate, or only on one side, and a protective layer may be provided if necessary.

Alternatively, an air sandwich structure may be used in which two recording media (one of which may only be a substrate) are sealed with the recording layer inside, or a close-contact sandwich structure in which two recording media are bonded with a protective layer interposed therebetween.

The amount of the compound of general formula (1) in the recording layer is usually 10 to 100.
%, preferably 50 to 100%.

The thickness of the recording layer is usually 300 to 1 μm, preferably
The number ranges from 500 to 3000 people.

To record on the recording layer, laser light focused to about 1 μm, preferably semiconductor laser light, is applied to the recording layer, and thermal deformation of the recording layer such as decomposition, evaporation, sublimation, and melting is caused by absorption of laser energy. To do this.

Recording can be reproduced by reading changes in reflectance between areas where thermal deformation has occurred and areas where thermal deformation has not occurred using laser light.

Various lasers such as a He-Ne laser, an Ar laser, and a semiconductor laser can be used as the light source, but
Semiconductor lasers are preferred in terms of cost and size.

[Examples] The present invention will be further described below with reference to Examples, but the present invention is not limited thereto.

In the examples, % is by weight.

Example 1 A 0.5% ethyl cellosolve solution of the No. 1 compound in Table 1 was coated on an acrylic resin substrate by a spinner coating method, and then dried at 90°C for 1 hour to produce optical information having a recording layer of 800 layers. Obtained a recording medium.

The maximum absorption wavelength measured by the spectrophotometer was 790 nm, and the shape of the spectrum was wide.

The optical information recording medium created in this way was mounted on a turntable, and the turntable was rotated at 1800 rpm by a motor.
5 mV and 8 MHz Ga-Al-As
Recording was performed by focusing a semiconductor laser onto the surface of the recording layer with a spot size of 1.0 μm and irradiating it in the form of a track.

When the recorded surface was observed using a scanning electron microscope, clear bits were observed.

Furthermore, when a low-power semiconductor laser was applied to the substrate on which this bit was formed and the reflected light was detected, the S/N ratio was 53 dB, indicating that good signal writing and reading could be performed.

In addition, this recording medium was placed in indoor light at a temperature of 60°C and a humidity of 9°C.
After standing for one month under 0% conditions, the maximum absorption wavelength was measured with a spectrophotometer and was found to be 790 ryn, showing very good storage stability with no change at all.

Example 2 A 0.5% ethyl cellosolve solution of compound No. 4 in Table 1 was coated on an acrylic resin substrate by a spinner coating method, and then dried at 90°C for 1 hour to form an optical fiber having a recording layer of 850 people. Obtained an information recording medium.

When laser light was irradiated in exactly the same manner as in Example 1, the S/N ratio was 52 dB, and good signal writing and reading could be performed.

Moreover, the storage stability was also extremely good.

Comparative Example 1 Vacuum degree 10 on a polycarbonate resin substrate with a thickness of 1 mm
The hexadecafluorophthalocyanine steel compound was then heated to 300 to 4000 C, and a thin film having a thickness of 840 mm was deposited by vacuum evaporation to obtain an optical information recording medium.

The maximum absorption wavelength measured by a spectroscopic altimeter was 820 nm, and the spectral shape was wide.

Recording was performed on the recording medium thus obtained in the same manner as in Example 1, and the reflected light was detected in the same manner.
/N ratio was 52 dB, and good signal writing and reading were possible.

Moreover, the storage stability was also extremely good.

Comparative Example 2 A 1% ethyl cellosolve solution of tetra-t-butyl phthalocyanine pb compound was coated on an acrylic resin substrate by a spinner colting method, and then dried at 90°C for 1 hour to produce optical information having a recording layer of 900 layers. Obtained a recording medium.

The maximum absorption wavelength measured by the spectrophotometer was 800 nm, and the shape of the spectrum was wide.

Recording was performed on the recording medium thus obtained in the same manner as in Example 1, and the reflected light was detected in the same manner.
The ratio was 46 dB.

Moreover, the storage stability was also extremely good.

[Effects of the Invention] The optical information recording medium of the present invention has the following effects: (1) good solubility in solvents;

Therefore, a thin film can be easily formed by the coating method, resulting in good productivity.

(2) High recording and reproducing sensitivity.

(3) Good storage stability over a long period of time.

Conventional media using cyanine, squarylium, naphthoquinone, etc. have poor stability and are difficult to store for long periods of time, but the present invention does not have these problems.

(4) Good stability against heat.

Organic dye compounds generally used in optical information recording media are unstable to heat. The material of the present invention is stable against heat, so there is no such problem.

(5) Good water resistance (humidity resistance).

(6) Good resistance to oxidation.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the formula, R_1, R_2, R_3, R_4, R_5, R_
6, R_7, R_8 are hydrogen atoms or alkyl groups, R_1, R_2, R_3, R_4, R_5, R_6,
The total number of carbon atoms in R_7 and R_8 is 4 or more. M is 2
H, metal, metal oxide, or metal halide. ) An optical information recording medium comprising a recording layer containing a compound represented by: