JPS613793A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To enable the regeneration of recording by long wavelength light and to make it possible to obtain high recording density excellent in preservability and reduced in regenerative deterioration, by providing a recording layer containing a double salt consisting of a color cation and a metal complex anion. CONSTITUTION:A recording layer 2 containing a double salt is provided onto a substrate 1. The formation of the recording layer 2 is performed by applying the solution containing the double salt to the substrate 1. As the org. solvent for dissolving the double salt, alcohols such as methanol, ethanol or isopropanol are used and, as the substrate, glass, polyester or polyamide is used. The double salt is formed by mixing a solution containing a compound of a color cation and the counter ion thereof with a solution containing a metal complex anion and the counter ion thereof. Recording can be performed with high sensitivity even if long wavelength laser is used and a pit is formed in a good shape while a high C/N ratio is obtained and the high stability and excellent preservability against heat and light is imparted and regenerative deterioration is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical information recording medium having a recording layer containing a specific double salt. More specifically, the present invention relates to an original information recording medium used in a method of directly recording and reproducing information using a laser beam.

[Prior art]

2. Description of the Related Art Conventionally, five information recording and reproducing apparatuses have been known that record and reproduce information by irradiating a rotating disc-shaped information recording medium with a laser beam. As a recording layer of an information recording medium used in this type of information recording device, a recording layer using a low melting point metal or a low melting point metal and a dielectric material has been proposed.

However, these have drawbacks such as poor storage stability, low resolution, low recording density, and high cost. Also,
Recently, it has been proposed to use an organic dye thin film whose physical properties can be changed by light having a relatively long wavelength as a recording layer. Although this organic dye thin film eliminates the above-mentioned drawbacks, organic dyes that generally have absorption characteristics on the long wavelength side have problems such as low stability against heat and light. Therefore, it has been proposed to include a metal complex in the organic thin film recording layer.

However, the current situation is that sufficient recording and reproducing characteristics cannot be obtained simply by mixing an organic dye and a metal complex in this way.

〔the purpose〕

The present invention has been made in view of the above-mentioned current situation, and its purpose is to provide an optical information recording medium that is capable of recording and reproducing using long wavelength light such as a semiconductor laser, has excellent storage stability, has little reproduction deterioration, and has a high recording density. It is to be.

〔composition〕

The present inventor conducted extensive research to achieve the above object and found that a double salt consisting of a dye cation and a metal complex anion is useful as a stable loading material, leading to the completion of the present invention.

That is, the invention is characterized by having a recording layer containing a double salt consisting of a dye cation and a metal complex anion,
An object of the present invention is to provide an optical information recording medium.

The double salt of the present invention is a new substance, and the following method can be mentioned as a general method for producing it.

1. Method using solubility difference a) Crystallization of a double salt A solution of a compound consisting of a dye cation and its counter ion and a solution of a compound consisting of a metal complex anion and its counter ion are mixed to form a dye cation. The desired double salt with the complex anion is crystallized. At this time, the mixed solution may be concentrated and cooled if necessary. As the counter ion, it is preferable to use one with high solubility. As the solvent, a single solvent, a poor solvent for double salts, and a good solvent for counter ions can be used. Further, for the purpose of promoting crystallization, other salts may be added for salting out.

b) Crystallization of counter ions Contrary to the case of a) above, counter ions can be crystallized to obtain a desired double salt of a dye cation and a complex anion as a precipitate.

In this case, a single solvent, a good solvent for double salts, and a poor solvent for counter ions can be used6.
Further, for the purpose of promoting crystallization of counter ions, other salts may be added for salting out.

2. Method using ion exchange resin 8) Production using cation exchange resin A double salt can be obtained by adsorbing dye cations using a cation exchange resin and then ion-exchanging the metal complex solution.

b) I! Formation using ion exchange resin 1≠A double salt can be obtained by ion-exchanging a recoloring IA solution in which metal complex anions have been adsorbed using an ion exchange resin.

For producing the double salt of the present invention by the method described above, one ion source is a compound consisting of a dye cation and its counter ion, and the other ion source is a metal complex anion and its counter ion. It is necessary to use a compound that Representative examples of the above dye cations include those represented by formulas (0 to (xm)) below.

1) Polymethine dye (IT) However, in the above formulas (1) to (b), A, BSD and E represent substituted or unsubstituted aryl groups.
% 82% "5
Indicates a divalent residue having the atomic group necessary to complete a membered ring, and 9 and R9 may be the same or different and each represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group or alkenyl group,
zl and Z2 represent a 0K6bt'fk atomic group that completes a substituted or unsubstituted bicyclic ring, z5 represents an atomic group necessary to complete a substituted or unsubstituted 5-membered ring or 6-membered ring, and The 5-membered ring or 6-membered ring may be fused with an aromatic ring. represents a group, an alkyl group, a substituted or unsubstituted aryl group or an acyloxy group, and l, m and n are 0 or 1.

2) Triarylmethane dye Ar5 Thin viscosity However, in the above formulas (7) and (b), Rj, R2
and Rs may be the same or different and each represents a hydrogen atom, hydroxy, a halogen atom, 01 to C2Q
represents an alkyl group or -N(C1-CIQ alkyl)2, lSm and n represent 0 or 1-9, Ar1,
Ar2 and Ar5 may be the same or different and each represents a substituted or unsubstituted aryl group, 8,
t and U indicate 0 or 1 to 3, and s+t+u=
It is 3.

3) Beryllium dye (VW) However, in the above formulas (2) and (2), x, xl and R2 represent a sulfur atom, oxygen atom or selenium atom, and 2 and zl are optionally substituted biryllium, thiopyrylium , Selenapyrilium, Benzobyrylium,
Indicates a hydrocarbon group consisting of the atomic group necessary to complete penzothiopyrilicum, benzoselenapyrylium, naphthopyrylium, naphthothiopyrylium or natutoselenapyrylium, and Z2 may be substituted. Piran,
Indicates a hydrocarbon group consisting of the atomic group necessary to complete thiopyran, selenapyran, (nzopyran, inzothiopyran, penzoselenapyran, naphthopyran, naphthothiopyran or naphthoselenapyran, R1, R2, R8
and ``denote'' represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, R5,
R4 and R7 are hydrogen atoms, halogen atoms, substituted or unsubstituted alkyl groups, and substitutions are also 1. < represents an unsubstituted aryl group or a substituted or unsubstituted aralkyl group, m and I represent 1 or 2, and n represents 0.1 or 2.

4) Phenanthrene dye However, in the above formula (phantom and α), R1 and R2
represents an alkyl group, R3, R4 and R5 are hydrogen atom, hydroxyl, hydrogen atom, substituted or unsubstituted alkyl, aryl, aralkyl, n is 0 or 1-6
shows.

5) Tetrahydrocholine dye, where R is alkyl, carbalkoxy, e.g. COO
C2H5, etc., R1 represents hydrogen, alkyl, etc., and [M is H% Ni (M), Co (1),
Represents Co (III), etc.

6) Triarylamine dye, however, R1-R in the above formulas (b) and (xm)
3,! , m1nSAr1 to Ar3, s, t, and U have the same meanings as described for formula (7) and (v) above.

Examples of counter ions for the above dye cations include chloride ion, bromide ion, iodide ion, perchlorate ion, benzenesulfonate ion, p-toluenesulfonate ion, methyl sulfate ion, and ethyl sulfate ion. , acid anions such as propyl sulfate ion.

There is a

Here, the table below shows representative examples of compounds consisting of the above-mentioned dye cation and counter ion, which serve as one of the ion sources (dye cations) used in the production of uninvented double salts. is not limited.

Formula (It)-1 HHHHHLJ cito4 # # # # C7l#
## #HLJl1 ##CJ#
p y p 14 L,,l #11
1111 LJ # # # I BrINI
INSU SO3 building H3 # # I # C71R,
< R7 zspzz H'fl p tt p z z @g Cl0a
R? R10j p CH3HOI C4H5+ C1y ClCH3H
l 02H5# # ICl3 C2H5H30B+H5 CH3Br # 804-CH3C4H
? C4H? H804-C2H50M30H
5HH1r C2H5C2H5N Cl CH3CH! l # 05H703H7 C4Hq C4Hq #
ttCH3CH3I I 11
NBOs ((Anti-CM! I C2H5C2H5 C3H7C3H71C2H5-804 CH5' CH5Cj # CH38
04s OClO4 In addition, as an example of the above metal complex anion, the following formula (Xf
Examples include those represented by f) to formula (XXfv), but the present invention is not limited to these.

■ 1g However, in the above formulas (xyv) to (xx), M represents a transition metal such as Ni, COlMn, Cu, Pd, and pt, and R1 to R1 may be the same or different (each may be substituted or unused). Represents a substituted argyl, aryl or amino group, R5 to R12 may be the same or different and each represents a hydrogen atom, a hydrogen atom, or a substituted or unsubstituted alkyl, acyl, alkoxy, acyloxy, aryl, alkenyl or represents an amino group, R15 represents a substituted or unsubstituted amino group, 1, m5nXpXQ and r represent ol or 1-4, and U and V represent 0 or 1-2.

represents a transition metal such as Co, Mn, Cu, Pt, or Pd, R1 represents hydrogen, an alkyl group, a phenyl group, or a naphthyl group, and the phenyl group and the naphthyl group represent an alkyl group, an alkoxy group, an amino group, an alkylcarbonyl group. , a phenylcarbonyl group or a halogen, R2 represents hydrogen or an alkyl group, and R represents hydrogen, an alkyl group, an alkoxy group, a halogen or an amino group.

However, in the formula, M represents a transition metal such as N1, Co, Mn, CuSPt or Pd, and A represents N or =CH
-CH=N-, X is hydrogen, halogen, c1-C
6 represents an alkyl group or an amino group, Yl and Y2
may be the same or different and each is hydrogen, halogen, alkyl group, 2) "a, C1-C6 alkoxysulfonyl &, c1-C6 alkylsulfonyl group, carbamoyl group, c2-C6 furkylcarpamoyl i, c'2-c6 alkoxycarbamoyl group, 07-C
11 Allylcarbamoyl group or 07-C11 allyloxycarbonyl group.

The counter ion for the above metal complex anion is a cation such as a quaternary ammonium ion, and in order to provide the ion source (metal complex anion) for the production of the #1 salt of the present invention, for example, the following The compounds shown in can be used.

N (CxH7) 2 Among the metal complex anions mentioned above, those having an absorption ability in a longer wavelength region than the maximum absorption wavelength of the dye cation are preferable. This is because it is thought that the quenching effect that promotes the deactivation process of the excited triplet state of the dye and the excited singlet state of oxygen is particularly large.

The recording layer in the present invention is capable of causing some optical change by irradiation with laser light and recording information based on the change, and the above-mentioned double salt of the present invention must be contained in the recording layer. . Further, in forming the recording layer, the above-mentioned double salts may be used alone or in combination of two or more. Further, the double salt of the present invention can be mixed and dispersed in various materials such as polymeric materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones, and liquid rubbers, or silane coupling agents. It may be used together with stabilizers, dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, etc. for the purpose of improving properties.

In addition, in forming the recording layer, the double salt of the present invention can also be used in combination with a metal complex having a metal complex anion of formula (XIV) to formula (XXIV) listed above.

The thickness of the recording layer is in the range of 100X to 1 μm, preferably 200X to 2000X, when not used in combination with a binder (for example, the above-mentioned polymeric material), and in the range of 100X to 5 μm, preferably 200A to 1 μm, when used in combination with a binder. be. Further, it is desirable for the recording layer to have a reflectance of at least 15% from the substrate side for recording and reproduction.

Next, the structure of the optical information recording medium according to the present invention will be explained with reference to one drawing.

As shown in FIG. #r1, the optical information recording medium of the present invention basically has a recording layer 2 containing the double salt of the present invention provided on a substrate 1. Further, the recording layer can also have a two-layer structure in which a light-reflecting layer and a light-absorbing layer are combined in any order.

The recording layer is preferably formed by coating a double salt solution on the substrate. Solution application is carried out by conventional coating methods such as spraying, four-color coating, dipping and spinning. Organic solvents for dissolving double salts generally include alcohols such as methanol, ethanol, and isozolopanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and N
Amides such as N-dimethylformamide and NUN-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, Aliphatic halogenated hydrocarbons such as dichloroethane, carbon tetrachloride, trichloroethane, etc., or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used. Furthermore, vapor deposition, snootling, cVD, etc. can also be used to form the recording layer.

When writing and recording from the substrate side, the substrate 1 must be transparent to the laser beam used, and must be transparent to the laser beam used.
! The S combination made from t fllll need not be transparent. Substrates include glass, polyester, polyamide,
Plastics such as polyolefin, polycarbonate, epoxy, polyimide, polymethyl methacrylate,
Metals and ceramics are usually used, but any other material used for recording media may be used.

Furthermore, as shown in FIGS. 2 to 4, the structure shown in FIG. 1 may be further provided with an undercoat layer 3 and/or a protection layer 4.

At this time, the 9 salt of the present invention may be contained in the undercoat layer crucible and/or the protective layer. In addition, the subbing layer or the protective layer contains stabilizers, dispersants, flame retardants, etc. Other additives such as an antistatic agent, an active agent, a plasticizer, etc. may also be present.

The subbing layer 3 has the following functions: (a) improving adhesiveness, (b) acting as a barrier against water or gas, (C) improving storage stability of the recording layer, and (d)
) It is used for the purpose of improving the reflectance, (protecting the substrate from the 81f # agent, and (f) forming a pregroove. Various substances can be used (
For purposes b) and (c), inorganic compounds such as 8102, MgF2.81 (IXTi0
2. Metals or metalloids such as ZnO1TiN, 81N, etc. such as ZnSCu, S, Ni, Cr, Ge, 8
e.

Cd, AgXAJ, etc. can be used. (d)
For this purpose, metals such as A/, AFS etc. or organic thin films with metallic luster such as methane dyes, medium nandene dyes etc. can be used and <6), <f)
For this purpose, ultraviolet curing resins, thermosetting resins, thermoplastic resins, etc. can be used.
．． A suitable range is 1 to 30 μm, preferably α2 to 10 μm. The protective layer 4 is provided for the purpose of protecting the recording layer from scratches, dust, dirt, etc. and improving the chemical stability of the recording layer, and the same material as the undercoat layer can be used for the protective layer 4. The thickness of the protective layer I7 is suitably 0.1 μm or more, preferably 50 μm or more.8 Furthermore, as another configuration of the optical information recording medium according to the present invention, two sheets having the same configuration as shown in FIGS. 1 to 4 are used. It is also possible to use a so-called air sandwich structure in which a recording medium (sacrificial layer 2 is used as the substrate) and the recording layer 2 is placed inside and sealed, or a so-called close contact structure in which the recording layer 2 is placed inside and sealed. A sandwich structure (mother-in-law structure) may also be used.

Note that if a semiconductor laser with a wavelength of 750 to 850 nm is used as the laser light source, the device can be made smaller.

〔Example〕

The present invention will be further explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Production Example Production of Double Salt A solution was prepared by dissolving compound 11 of the following formula (1) in a 1-5% mixed solvent of acetone and ethyl alcohol. Next, 1.4g of the compound of formula (2) below was added to 11g of acetone.
00t/ to prepare an acetone solution, and this solution was gradually poured into the acetone-ethyl alcohol solution without stirring.The mixture was then concentrated in an evaporator, and then cooled in a refrigerator to precipitate crystals. I let it happen. The crystals were washed several times with a 1:4 mixed solvent of acetone and ethyl alcohol to obtain a pure double salt.

When the double salt obtained as described above was subjected to thin layer chromatography, R
Only a single spot with f value was detected. The visible and ultraviolet absorption spectrum of a 1,2-dichloroethane solution of the obtained double salt crystal is shown in FIG. The absorption spectra of the compounds of formula (1) and formula (2) are shown in FIG. Comparing Figures 5 and 6, it is clear that the generated crystals exhibit absorption unique to the double salt, and when considered together with the results of the I1 layer chromatography described above, it is clear that the produced crystals exhibit absorption unique to the double salt. It was identified as a double salt.

Examples 1 to 12 A 0.75% 1,2-dichloroethane solution of each double salt consisting of a dye cation and a metal complex anion shown in the table below was prepared. Next, each solution was spin-coated onto a polymethyl methacrylate (hereinafter abbreviated as "PMMA") substrate with a thickness of 1.2 mm to form each recording layer with a thickness of about 500 mm, thereby producing each recording medium.

Examples 13 to 15 Each recording medium was produced by providing a silver vapor deposited film with a thickness of 1 oou on a PMMA substrate with a thickness of 1.2 fins, and further providing each recording layer thereon in the same manner as in Examples 1 to 3. .

Comparative Examples 1 to 4 Dye cations and counter anions shown in the table below
O,75
9g 1,2-dichloroethane solution was added to vI4ML.

Next, each solution was spin-coated onto a PMMA substrate with a thickness of 1.2 mm to form each recording layer with a thickness of about 5 mm, thereby producing each recording medium.

Each recording medium produced in the above Examples and Comparative Examples had a wavelength of 7.
Using a 90 nm semiconductor laser beam, the writing power was 2.25 mW from the substrate side, the recording frequency was 0, 5 MH2,
Information is written and reproduced at a linear velocity of 1.5 m/sea, and its speed is analyzed using vector analysis (scanning filter, bandwidth 30 m/sea).
KHz) was performed to measure c/N.

Next, the reflectance and C/N were measured after irradiating the same recording medium with 54,000 lux tungsten light for 50 hours. Note that the reflectance was measured from the substrate side. The results are summarized in the table below.

Next, when the recording layer contains a pre-formed double salt as in the present invention (hereinafter referred to as "double salt system"), and when the dye compound and the metal complex are contained separately! The effect of containing it in e-recording waste (hereinafter referred to as "mixed system") was further investigated.

A sample of the present invention was prepared by spin-coating a solution of 75wt% of the double salt produced in the above production example dissolved in 1.2-') chloroethane onto a PMMA substrate to form a thin film with a thickness of 600X. . On the other hand, for the purpose of comparison, the formula (
A 1,+-:) chloroethane solution prepared by mixing the compound of 1) and the compound of formula (2) at an iti ratio of 1=1 was spin-coated onto a PM substrate to form a thin film with a thickness of 600^, and a comparative sample was prepared. was created. Visible absorption spectrum analysis was performed on each of the samples thus prepared, and it was found that the sample made from the double salt system of the present invention had both absorption and reflection at a wavelength of 790 nm about 10% higher than the comparative sample made from a mixed system.

Furthermore, when the recording properties of a recording medium using the above-mentioned double salt recording layer and a recording medium using the above mixed-system recording layer of the present invention were examined, the following results were obtained.

Double salt system 27.1 55 22.8 46
21.7 49 Mixed system 25.1 51 20
．． 5 42 1 & 8 42 From the above results, it is clear that the double salt system of the present invention has improved raw storage stability and regeneration stability compared to the mixed system. This is because in the double salt system of the present invention, the interaction between the dye cation and the metal complex anion in the film forming state is greatly stabilized compared to the mixed system, and compared to the mixed system, the interaction between the dye cation and the metal complex anion is greatly stabilized. This is thought to be because there are no counter ions in the recording layer.

〔effect〕

The optical information recording medium of the present invention configured as described above can have the following effects.

1. Even if a long wavelength laser (semiconductor laser) is used, recording can be performed with high sensitivity.

2. Able to form bits with good shape and high C
/N is obtained.

3. High stability against stress and light (, excellent storage stability,
A recording medium with little reproduction deterioration can be obtained.

[Brief explanation of drawings]

1 to 4 are cross-sectional views showing the structure of the original information recording medium of the present invention, and FIGS. 5 and 6 are absorption vectors for identifying double salts according to the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Recording layer, 3... Undercoat layer, 4
...protective layer.

Claims (1)

[Claims] An optical information recording medium characterized by having a recording layer containing a double salt consisting of a dye cation and a metal complex anion.