JPH0796335B2 - Optical recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is an optical recording medium using an infrared absorbing compound.

In particular, the present invention relates to an infrared absorbing compound and an optical recording medium that improve durability and light resistance in repeated reproduction in an optical disc or an optical card.

[Conventional technology]

In general, an optical disc and an optical card have a small (for example, about 1 μm) optically detectable pit formed on a thin recording layer provided on a base, and are formed into a spiral or circular and linear track shape to have a high height. Density information can be stored. To write information to such a disk,
A focused laser is scanned on the surface of the laser-sensitive layer and only the surface irradiated with this laser beam forms pits, which are formed in the form of spirals or circles and linear tracks. The laser sensitive layer can absorb laser energy to form an optically detectable pit. For example, in the heat mode recording method, the laser-sensitive layer absorbs thermal energy, and a small recess (pit) can be formed at that portion by evaporation or melting. Further, in another heat mode recording method, a pit having an optically detectable density difference can be formed at the position by absorbing the irradiated laser energy.

Here, by using an organic dye thin film as the recording layer having a high reflectance, the optical contrast of the recording pit can be set high. For example, as an organic dye thin film,
When polymethine dyes, azulene dyes, cyanine dyes, pyrylium dyes, etc. that have high light absorption for laser light are used, a light absorbing / reflecting film exhibiting a metallic luster (reflectance of 10 to 50%) can be obtained, and laser recording can be performed. It becomes an optical recording medium which can be read out by reflection. Especially as a laser light source
The use of a semiconductor laser of 700 to 900 nm has the advantage that the device can be downsized and the cost can be reduced. However, the organic dye thin film generally has a problem that the recording and reproducing characteristics and the storage stability, that is, the repeated reproducing durability and the light resistance are deteriorated due to the fact that the substance is easily changed by heat and light.

[Problems to be solved by the invention]

An object of the present invention is to provide an optical recording medium having repeated reproduction durability and light resistance.

[Means for solving problems]

The above object of the present invention is to provide a recording layer comprising an organic dye thin film with a compound selected from the following general formulas (1) and (2) in an amount of 1 to 60% by weight based on the total solid content of the recording layer.
It is achieved by an optical recording medium characterized by including.

(A in the formula isAnd B isIndicates Indicates an anion. R₁To R₈Is from 1 carbon
Up to 8 substituted or unsubstituted alkyl groups, substituted or not
Is an unsubstituted alkenyl group, or a substituted or unsubstituted
Aralkyl group or alkynyl group, and R₁And R₂, R₃And R
_Four, R_FiveAnd R₆, And R₇And R₈Replace with N in combination
Or an unsubstituted 5-membered ring, a substituted or unsubstituted 6-membered ring
A ring or a substituted or unsubstituted 7-membered ring may be formed. R₁
To R₈May have the same or different substituents
Good. ) In addition, the central aromatic ring is a lower alkyl group or halogen.
It may be substituted with a group.

X Is chloride ion, bromide ion, iodide ion
Ion, perchlorate ion, nitrate ion, benzenesulfo
Phosphate ion, P-toluenesulfonate ion, methyl
Sulfate, ethyl sulfate, propyl sulfate
Ion, tetrafluoroborate ion, tetraphenyl
Ruborate ion, hexafluorophosphate ion,
Nenselsulfate ion, acetate ion, triflu
Oroacetate ion, propionate ion, benzoate
Ion, oxalate ion, succinate ion, malon
Salt ion, oleate ion, stearate ion
Ion, citrate ion, monohydrogen diphosphate ion, diwater
Elemental monophosphate ion, pentachlorostannate ion,
Lorosulfonate ion, fluorosulfonate ion
Ion, trifluoromethanesulfonate ion, hexaf
Luoro arsenate ion, hexafluoroantimonate a
On, molybdate ion, tungstate ion
Anions such as titanium, titanate ions, and zirconate ions.
Indicates ON.

The production methods of the present compounds (1) and (2) are described in US Patent Specification No. 3251881, US Patent Specification No. 3575871, US Patent Specification No.
The methods described in 3484467 and JP-A-61-69991 can be used. For example, it can be manufactured by the following process.

That is, the final product can be obtained by selectively alkylating, alkenylating, aralkylating, or alkynylating the amino compound obtained by the Ullmann reaction and reduction reaction, and then performing the oxidation reaction.

R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are alkyl groups such as methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group. , sec-butyl group, iso-butyl group, t-butyl group, n-amyl group, t-amyl group, n-hexyl group, n-octyl group, t-oltyl group and the like, further alkyl group, For example, as the substituted alkyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, 4-hydroxybutyl group, 2-acetoxyethyl group, carboxymethyl group, 2-carboxyethyl group, 3-carboxypropyl group, methoxyethyl group, Examples of alkenyl groups such as ethoxyethyl group and methoxypropyl group include vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group and octenyl group, and examples of aralkyl groups include benzyl group and p-chlorobenzyl group. , p Methylbenzyl group, 2-phenylmethyl group, 2-phenylpropyl group, 3-
Examples of alkynyl groups such as phenylpropyl group, α-naphthylmethyl group and β-naphthylethyl group are, for example, propargyl group, butynyl group, pentynyl group, hexynyl group, etc. As the substituted or unsubstituted 6-membered ring, for example, piperidine ring, morpholine ring, tetrahydropyridine ring and the like, and as the substituted or unsubstituted 7-membered ring, cyclohexylamine ring and the like. Further, when R ₁ to R ₈ are asymmetrical, it is necessary to carry out the alkylation in multiple stages, and it is preferable in terms of cost that R ₁ to R ₈ are the same.

Next, specific examples of the compounds used in the general formulas (1) and (2)
Here's an example. For simplification, the compound represented by the formula 1)
A, X, (R₁R₂) (R₃R_Four) (R_FiveR₆) (R₇R₈), In equation (2)
The compound represented by B, X, (R₁R₂) (R₃R_Four) (R_FiveR₆) (R₇
R₈). For example, in equation (1), A isX Is ClO_Four And R₁To R₈Is C₃H₇If it is, ClO_Four , (C₃H₇C₃H₇)_FourIt is written as. Also, in equation (2), B
But X Is ClO_Four And R₁To R₂Forms a piperidine ring, R₃
To R₈Is an n-butyl group,ClO_Four , (C_FourH₉C_FourH₉)_Three(CH₂CH₂CH₂CH₂CH₂)
It

Such an aluminum salt compound or diimonium salt compound has a maximum absorption wavelength of 900 nm or more and an absorption coefficient having a large absorption peak of about tens of thousands to hundreds of thousands.

Such compounds are used not only as materials for optical recording media but also as heat insulating films and sunglasses.

As the near-infrared absorbing dye used in combination with these compounds as an optical recording medium, commonly known dyes are used, for example, cyanine dyes, merocyanine dyes, croconium dyes, squarylium dyes, azurenium. Dyes, polymethine dyes, naphthoquinone dyes, pyrylium dyes, phthalocyanine dyes, etc.

The amount of the aminium salt compound of the general formula (1) or the diimonium salt compound of the general formula (2) added to these dyes is 1 to 60% by weight, preferably 1 to 60% by weight, based on the total solid content of the recording layer. 5-40% by weight, more preferably 10-30
Weight percent is suitable.

In addition to these compounds, a binder may be contained in the recording layer. Examples of the binder include nitrocellulose, cellulose phosphate, cellulose sulfate, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose myristate, cellulose parimitate, and acetic acid.
Cellulose esters such as cellulose propionate and cellulose acetate / butyrate, cellulose ethers such as methyl cellulose, ethyl cellulose, propyl cellulose and butyl cellulose, polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyvinyl pyrrolidone. Such as vinyl resins, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, copolymer resins such as vinyl chloride-vinyl acetate copolymer, polymethylene methacrylate, polymethyl acrylate,
Acrylic resins such as polybutyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide and polyacrylonitrile, polyesters such as polyethylene terephthalate, poly (4,4'-isopropylidene diphenylene-co-1,4-cyclohexene) Cilendimethylene carbonate), poly (ethylenedioxy-3,3'-phenylene thiocarbonate), poly (4,4'-isopropylidene diphenylene carbonate-co-terephthalate), poly (4,4'-isopropyiene) Polyarylate resins such as poly (4,4'-sec-butylidene diphenylene carbonate), poly (4,4'-isopropylidene diphenylene carbonate-block-oxyethylene), or Polyamides, polyimides, epoxy resins, Enol resins, may be used polyethylene, polypropylene, and the like polyolefins such as chlorinated polyethylene.

Further, the recording layer may contain a surfactant, an antistatic agent, a stabilizer, a dispersible flame retardant, a lubricant, a plasticizer and the like.

Further, a protective layer may be provided between the recording layer and the substrate in the form of an undercoat layer or a recording layer.

As the undercoat layer, the protective layer may be scratched or scratched in order to impart solvent resistance, improve reflectance, or improve repeated reproduction.
It is used for protection from dust and dirt, and for environmental stability of the recording layer. The materials used for these are mainly inorganic compounds, metals or organic polymer compounds. Examples of the inorganic compound include SiO ₂ , MgF ₂ , SiO, TiO ₂ and Z.
Examples of metals such as nO, TiN, and SiN are Zn, Cu, Ni, Al, Cr, and G.
As the organic polymer compound such as e, Se, Cd, ionomer resin, polyamide resin, vinyl resin, natural polymer, epoxy resin, silane coupling agent, etc. can be used.

As the substrate, polyester, polycarbonate, acrylic resin, polyolefin resin, phenol resin, epoxy resin, polyamide, polyimide or other plastic, glass or metals can be used.

The organic solvent that can be used during coating should be in a dispersed state,
Or, depending on whether it is dissolved or not, it is generally alcohols such as methanol, ethanol, isopropanol, diacetone alcohol, acetone, methyl ethyl ketone, ketones such as cyclohexano, N, N-dimethylformamide, N, N-dimethylacetamide, etc. Amides, sulfoxides such as dimethyl sulfoxide, tetrahydrofuran, dioxane, ethers such as ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate, butyl acetate, chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, Aliphatic halogenated hydrocarbons such as trichloroethylene, benzene, toluene, xylene, monochlorobenzene, dichlorobenzene aromatics or n-hexane, cyclohexanoligroin What aliphatic hydrocarbons or the like can be used.

The coating can be carried out using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method or a curtain coating method.

The recording layer formed using such a solvent has a winding pressure of 50Å
-100 μm, preferably 200Å-1 μm.

〔Example〕

 Next, examples of the present invention will be described in detail.

<Synthesis Example 1> 1,5-diaminonaphthalene 0.1 mol, P-nitrochrome benzene 0.43 mol, anhydrous potassium carbonate 0.21 mol, copper powder 2
Parts (weight) in 120 parts of dimethylformamide with stirring,
Reflux was carried out for 4 days. After the reaction, the reaction mixture was filtered, and the filtered material was washed well with dimethylformamide, water and acetone and then dried to obtain 30 parts of reddish brown tetrakis (P-nitrophenyl) -1,5-diaminonaphthalene.

23 parts of the compound obtained above was added to an autoclave together with 90 parts of dimethylformamide palladium-carbon hydrogenation catalyst of 90 parts, and hydrogen gas was charged to 5.0 Kg / cm ² at 90 ° C to 100 ° C.
Stir underneath until hydrogen absorption ceases.

After the reaction, the reaction solution was filtered, the residue was washed with dimethylformamide, and the filtrate was poured into 350 parts of ice water. After stirring for a while, the precipitate was collected by filtration. Recrystallization was performed with an ethanol dimethylformamide mixed solvent to obtain 10 parts of tetrakis (P-aminophenyl) -1,5-diaminonaphthalene. Purity 98.9 by high performance liquid chromatography
%Met.

The results of infrared absorption analysis are shown in FIG.

<Synthesis of 1-16> The above amino compound (3 parts) was heated and stirred together with 18 parts of dimethylformamide, 0.7 parts of anhydrous sodium hydrogen carbonate and 3.9 parts of n-butyl bromide at 100 ° C to 130 ° C. After reacting for 36 hours, the reaction solution was poured into 100 parts of ice water and extracted with ethyl acetate. After drying, it was purified with a silica gel column. Acquisition amount 3.4
Part infrared absorption analysis confirmed the disappearance of absorption due to NH stretching vibration of amino group. (See FIG. 2) 0.5 part of this compound was dispersed in 20 parts of acetone, and equimolar silver perchlorate was added under stirring. After reacting for 1 hour at room temperature, the precipitated silver was filtered off, the filtrate was diluted with isopropyl ether and allowed to stand, and the precipitated crystals were collected by filtration. Acquisition amount 0.
It was 7 copies.

1-16 thus synthesized has a maximum absorption wavelength of 1120n.
The compound had a large absorption region in the infrared region with m and an extinction coefficient of 40,000.

<Synthesis of 2-16> 0.5 parts of tetrakis (p-dibutylaminophenyl) -1,5-diaminonaphthalene used in the synthesis of 1-16 was replaced with acetone.
It was dispersed in 10 parts, and 2 times mol of silver perchlorate was added with stirring. After reacting at room temperature for 1 hour, the precipitated silver was filtered off and the filtrate was diluted with isopropyl ether. 0.55 parts of precipitated crystals were collected by filtration.

The example explained above is the case where the anion is perchloric acid,
When another anion is used, the intended compound can be easily obtained by using a silver salt corresponding thereto. For _{example, AgSbF 6, AgBF 4, AgSO} 4, AgNO 3, AgSO 3 C 6 H 4 CH 3,
A silver salt such as AgSO ₃ CF ₃ can be used. In addition to this, it can also be obtained by electrolytic oxidation.

<Synthesis Example 2> 1,5-diaminonaphthalene used in Synthesis Example 1
The reaction was performed in the same manner as in Synthesis Example 1 except that 1,4-diaminonaphthalene was used, and tetrakis (p-aminophenyl)-
12 parts of 1,4-diaminonaphthalene was obtained.

<Synthesis of 1-13> 2 parts of the amino compound obtained in Synthesis Example 2 was replaced with dimethylformamide 12
Parts, 0.5 parts of anhydrous sodium hydrogen carbonate, and 2.7 parts of 2-ethoxyethyl bromide were heated and stirred at 100 ° C to 130 ° C. After reacting for 36 hours, the reaction solution was poured into 100 parts of ice water and extracted with ethyl acetate. After drying, it was purified with a silica gel column. It was confirmed that the absorption of amino group due to NH stretching vibration disappeared by infrared spectrophotometry with the obtained amount of 2,4 parts.

1 part of this compound was dispersed in 20 parts of acetone and stirred,
An equimolar amount of silver hexafluoride antimonate was added. After reacting at room temperature for 1 hour, the precipitated silver was filtered off, the filtrate was diluted with isopropyl ether and allowed to stand, and the precipitated crystals were collected by filtration.
The amount acquired was 0.8 part, and the maximum absorption wavelength was 1118 nm.

<Synthesis of 2-13> Tetrakis (p-dipropylaminophenyl) -1,4-diaminonaphthalene 1.0 obtained during the synthesis of 1-3
While 20 parts of acetone was dispersed and stirred, 2 times mole of silver perchlorate was added at room temperature and stirred for 1 hour. After the reaction, the precipitated silver was filtered off and washed well with acetone. Acetone was distilled off from the filtrate, washed with water, and then dried under reduced pressure. Yield
It was an infrared absorbing compound having a maximum peak at 0.65 parts and 1130 nm.

Next, examples in which the infrared absorbing compounds represented by the general formulas (1) and (2) are used as an optical recording material will be described.

<Example 1> A 50 μm pregroup was provided on a PMMA substrate having a diameter of 130 mmφ and a thickness of 1.2 mm, and a polymethine dye (Nippon Kayaku IR-
A liquid in which the organic dye of 820) and the infrared absorbing compound No. 1-16 were dissolved in 1,2-dichloroethane at a weight ratio of 90:10 was spin-coated to form a recording layer of 800 liters. Spacers of 0.3 mm were sandwiched on the inner and outer peripheries of the medium thus obtained and bonded to another PMMA substrate with an ultraviolet adhesive to obtain an optical recording medium having an air-sanding structure.

This was rotated at 1800 rpm, and writing was performed with a recording power of 6 mW and a recording frequency of 2 MHz from a substrate side using a semiconductor laser of 830 nm with a spot diameter of 1.5 μmφ. Next, reproduction was performed at a read power of 0.9 mW, and the C / N ratio was measured by spectrum analysis. Then, the C / N ratio was measured after 100,000 times of reading (repeated repetition).

Further, the recording medium prepared under the above conditions was irradiated with 1 KW / m ² of xenon lamp light for 100 hours to perform a light stability test, and the reflectance and C / N ratio were measured.

The results are shown in Table-1.

<Example 2> On the same substrate as in Example 1, in the same manner as in Example 1,
A recording layer was provided with a solution of 1-guaiazulenyl-5- (6'-t-butylazulenyl) -2,4-pentadienol perchlorate infrared absorbing compound No. 1-16 in a weight ratio of 90:10.

The same test as in Example 1 was conducted on the thus obtained optical recording medium. The results are shown in Table-2.

<Examples 3 to 7> An optical recording medium having the composition shown in Table 3 was prepared in the same manner as in Example 1, and the same test as in Example 1 was performed. The results are shown in Table-4.
Shown in.

<Comparative Examples 1 to 3> Optical recording media were prepared and evaluated in the same manner as in Examples 2 and 5, except that the infrared absorbing compounds used in Examples 1, 2 and 5 were excluded. The results are shown in Table-4.

<Examples 8 to 11> 0.4 mm thick card-sized polycarbonate (hereinafter referred to as "P
Abbreviated as "C") A pregroup is formed on a substrate by a hot pressing method, and a liquid prepared by mixing an organic dye and an infrared absorbing compound shown in Table 5 below in diacetone alcohol is applied thereon by a bar coating method. After that, it was dried to obtain a recording layer of 850Å. Furthermore, an optical recording medium having a contact structure was produced by a 0.3 mm thick PC substrate having a card size and a heat roll method through an ethylene-vinyl acetate film.

The optical recording medium of the example thus prepared was mounted on a stage driven in the XY directions, and a spot size of 3.0 μmφ was applied to the organic thin film recording layer from the side of the PC substrate having a thickness of 0.4 mm using a semiconductor laser having an oscillation wavelength of 830 nm. , Write power of 4.0mW with write pulse of 80μsec, write information in Y-axis direction and read with read power of 0.4mW, contrast ratio (A → unrecorded signal intensity, B → recorded signal intensity) were measured.

Further, the same recording medium manufactured under the above conditions was subjected to a light stability test under the same conditions as in Example 1, and thereafter the reflectance and the contrast ratio were measured. The results are shown in Table-6.

<Comparative Examples 5 to 6> Example 8 except that the infrared absorbing compound was removed in Examples 8 and 10.
An optical recording medium was prepared and evaluated by the same method as described in (10) and (10). The results are shown in Table-6.

[Advantages of the Invention] As described above, the compounds represented by the general formulas (1) and (2) have a large absorption region in the infrared region, and when used as an optical recording medium, the durability in repeated reproduction is high. Also, it is possible to provide a medium in which light stability is significantly increased.

[Brief description of drawings]

1 and 2 are infrared absorption spectra of the compound obtained in Synthesis Example 1 and the compound obtained in the synthesis of 1-16, respectively.

Claims (1)

[Claims] 1. A recording layer comprising an organic dye thin film, wherein
A compound selected from the general formulas (1) and (2) is added to the total solid content.
Based on 1 to 60% by weight of the recording layer.
Optical recording medium to be recorded. (A in the formula isOrIndicates X Indicates an anion. R₁To R₂Is 1 carbon
Up to 8 substituted or unsubstituted alkyl groups, substituted
Or an unsubstituted alkenyl group, or a substituted or unsubstituted
An aralkyl group or an alkynyl group, and R₁And R₂, R₃
And R_Four, R_FiveAnd R₆, And R₇And R₈Together with N
Substituted or unsubstituted 5-membered ring, substituted or unsubstituted 6
A membered ring or a substituted or unsubstituted 7-membered ring may be formed.
R₁To R₈The substituents of
May be. )