JPH03121889A - Infrared absorbing compound and optical recording medium using the same - Google Patents

Abstract

PURPOSE:To increase the durability and light-resistant stability in repeated reproduction by containing a specific infrared absorbing compound having a large absorbing region in an infrared part and good solubility. CONSTITUTION:An optical recording medium has an org. dye membrane containing an infrared absorbing compound represented by formula [I] wherein R1-R8 are a hydrogen atom, a halogen atom or a monovalent org. group and may be respectively different or same and R1 and R2, R3 and R4, R5 and R6 and R7 and R8 may be combined to form a 5-, 6- or 7-membered ring and X<e> is an anion). As a near infrared absorbing dye forming the org. dye membrane used together with the infrared absorbing compound, for example, there are a cyanine dye, a melocyanine dye or phthalocyanine dye. A proper load of the infrared absorbing compound composed of an aluminum salt compound represented by the formula I to the dye is pref. 10-30wt.% of a recording layer on a total solid basis.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an infrared absorbing compound and an optical recording medium using the same. This invention relates to an external absorption compound and an optical recording medium using the same.

[Prior Art] In general, optical disks and optical cards have optically detectable small bits (for example, about 1 μm) formed on a thin recording layer provided on the second side of a substrate in a spiral, circular, and linear shape. High density information can be stored in the form of tracks. To write information on such optical discs and optical cards, a focused laser is scanned over the surface of the laser sensitive layer, and bits are formed only on the surface irradiated with the laser beam, and these pits are shaped into spirals, circles, and straight lines. Formed in the form of a shaped track. The laser sensitive layer absorbs laser energy to form optically detectable pits. For example, in the heat mode recording method, the laser sensitive layer absorbs thermal energy and forms small pits at the locations due to evaporation or melting. In another heat mode recording method, absorption of irradiated laser energy can form pits having an optically detectable density difference at that location.

Here, by using an organic dye thin film as a recording layer with high reflectance, it is possible to set the optical contrast of the recording pits to be high. For example, as an organic dye thin film,
By using polymethine-based dyes, azulene-based dyes, cyanine-based dyes, biryllium-based dyes, etc. that have high light absorption against laser light, a light-absorbing and reflective film exhibiting metallic luster (reflectance of 10 to 50%) can be obtained, making laser recording possible. This makes the optical recording medium capable of reflective reading. In particular, when a semiconductor laser with an oscillation wavelength of 600 to 900 nm is used as a laser light source,
This has the advantage that the device can be made smaller and lower in cost. However, organic dye thin films generally have a problem in that their recording and reproducing characteristics and storage stability deteriorate because of their tendency to undergo material changes when exposed to heat and light.

[Problem to be solved by the invention] The present invention has been made in view of the prior art as described above, and its purpose is to provide a material that has a large absorption region in the infrared region and has good solubility. The purpose of the present invention is to provide an infrared-absorbing compound.

Another object of the present invention is to provide an optical recording medium which, when the novel infrared absorbing compound of the present invention is used in the optical recording medium, has significantly increased durability and light resistance stability during repeated reproduction.

[Means for Solving the Problem] and [Operation] That is, the present invention contains an infrared absorbing compound represented by the following general formula [I] and an infrared absorbing compound represented by the above general formula [1]. An optical recording medium characterized by having an organic dye thin film.

Q (In the formula, R1-R8 represent a hydrogen atom, a halogen group, or a monovalent organic residue. R1-R8 may be different or the same. Also, R+ and R2, R3 and R4
, a combination of R5 and R6 and R7 and Ra, a 5-membered ring,
A 6-membered ring or a 7-membered ring may be formed. xo represents an anion. ) In the above general formula [I], R1-R8 are hydrogen atoms,
Indicates a halogen group or a monovalent organic residue.

Examples of halogen groups include fluorine and chlorine.

Indicates bromine, iodine, etc. Monovalent organic residues include, for example, alkyl groups such as methyl, ethyl,
n-propyl group, 1so-propyl group, n-butyl group, 5ec-methyl group, 1so-butyl group, t-butyl group, n-amyl group, t-amyl group, n-hexyl group,
Indicates n-octyl group, t-octyl group, and other alkyl groups, such as substituted alkyl groups, such as 2-hydroxyethyl group, 3-hydroxypropyl group,
Examples of alkenyl groups include 4-hydroxybutyl group, 2-acetoxyethyl group, carboxymethyl group, 2-carboxyethyl group, 3-carboxypropyl group, methoxyedyl group, ethoxyethyl group, methoxypropyl group, etc., and examples of alkenyl groups include vinyl group and propenyl group. , butenyl group, pentenyl group, heptenyl group.

Aralkyl groups such as heptenyl group and octenyl group include benzyl group, p-chloropentyl group, p-methylbenzyl group, 2-phenylmethyl group, 2-phenylpropyl group, 3-phenylpropyl group, α-naphthylmethyl group, etc. Examples of the alkynyl group include a propargyl group, a butynyl group, a pentynyl group, and a hexyl group.

R1-R8 may be different or the same.

Also, R2 and R,, R3 and R4,) Is and I6 and R
2 and R8 in combination, a substituted or unsubstituted 5-membered ring,
A 6-membered ring or a 7-membered ring may be formed; the 5-membered ring is a pyrrolidine ring, and the 6-membered ring is a piperidine ring.

Examples of the morpholine ring, detrahydropyricine ring, and 7-membered ring include a cyclohexylamine ring. These rings may be turned or different.

xo is a chloride ion, a bromide ion, an iodine ion, a perchlorate ion, a nitrate ion, a benzenesulfonate ion, a p-toluenesulfonate ion, a methyl sulfate ion, an ethyl sulfate ion, a propyl sulfate ion,
Tetrafluoroborate ion, tetraphenylborate ion, hexafluorophosphate ion, benzenesulfinate ion, acetate ion, trifluoroacetate ion, propionacetate ion, benzoate ion, oxalate ion, succinate ion, malonate ion, oleate ion, stearate ion, citrate ion, -hydrogen diphosphate ion, dihydrogen-phosphate ion, pentachlorostannate ion, Chlorosulfonate ion, fluorosulfonate ion, trifluoromethanesulfonate ion, hexafluoroarsenate ion, hexafluoroantimonate ion, molybdate ion, tungstate ion, titanate ion, zirconate Represents anions such as salt ions.

Further, the central naphthalene ring in general formula [1] may be substituted with a lower alkyl group, an alkoxy group, a halogen group, a hydroxyl group, or the like.

The method for producing an infrared absorbing compound of the present invention is described in US Pat. No. 3,251,881, US Pat. No. 3,575,871,
U.S. Patent No. 3,484,467 and Japanese Unexamined Patent Publication No. 61-61
The method described in No. 9991 etc. can be used. For example, it can be manufactured by the following process.

112N-■-NH2+ 4 x+No2-1 → [NO
□(y TON-■-1(SawaNO□)2---→[u2N(
ytN-■-N+NH2]2 The amino compound obtained by the above Ullmann reaction and reduction reaction is substituted by selective substitution, for example, by alkylation, alkenylation, aralkylation, or alkynylation, and then the final product is obtained by oxidation reaction. I can get things.

If R3 to R8 are asymmetric, this alkylation etc. needs to be carried out in multiple stages, and from the viewpoint of cost it is preferable that R1 to R8 are the same.

Next, specific examples of the infrared absorbing compound represented by the general formula [I] according to the present invention will be given. For simplicity, X”ka CI
! 0<. Te, R1, R2, R: l, R4 are ethyl groups,
In the case of R5, R6, R7, R8 or a methyl group, CI! 0
4. C2H5, C2H5C2H5, C2H3C1 (
3, CH3CH3, CH3.

Also, xo or Brθ, R, and R2, R: l and R,, R
, and R6゜When R7 and R8 are combined to form a 5-membered ring, Br, CH2CH2CH2C++2 CH
□C1(□cH2GHz CH2Cl2CH2Cl1
It is expressed as 2C)12C)I2CH2C112.

In addition, in the present invention, R1-R8 are R1, R2, R
3, R4, R5, Re, R7 and R8 are not shown.

0 Compound ￥’p) No.

X R, R2 3R4 R,,R6 yRa [1]-(+1 [I]-(2) [I]-(3) cpo.

CI! 04 C1+3. C11゜C2115,C2H5 5bFa 0C2115,0(:2+15CH,
, CH13 C2H5, C2H5 0C2115, 0C211,.

OH3, CH3 C2H,,,C2H5 OC2H5, OC2+15 C13, CH:1 C2H5, C2H.

0(:2H5,0C2115 [I]-(5) [I]-(B6 [I]-(7) [I]-(B8 [I]-(9) [I]-(In) [I]- (u) [I]-(+12 [I]-(+13 [I]-(+14 [I]-(+15 [I]-(+16 C104n-C-A7.n-C3117SbFs
, 1so-C:+I17+ 1so-C:ti171
0C:4H9,0C4119CA'04C
L to 1'12cH', C:1bC1+=C)12Sb
Ft, C2H, CH=CH2, C2H4Cl=C
1l.

CIO4n-Cj(,,n-C,l+9c113%of
f n-ClJ2s, n (:+J2sCj)0.
C2H, C11=CI+2. C2H, CH=CH1
2cpo4 cH20cH3, CH□0CH3Sb
F6CJ1. +0C)I:+,C2H40CII:+N
O,0C21(S,OC2+15 sbF6 cu2c02c112cH□n-C3H
7,n-C3t17 iso-C,ll,, 1so-C:+ll70C4H
9, QC<ll5 C11□C=CH2, CH□[:H2C82CH2nl
=CH2,C211,CI(±CCH21-C4t(,
n-CJt9 n-CI2H2'i+n Cl2H25C2H4CH=
C82, C2H4CH=(:H2ell□QC)+3
, CH20CHsCJnOCH:+, CJ40Cib n-C:iH,, n-C:+1(7 CH2CH2(J12C11□ CIl,, CH3 n-CJ7.n-CJ7 iso-C, B7, 1so-C:+L QC, H9, OC, H9 011□C1(=CH(2,C11□C=CH2[:2
H4C: H=CI+2. C2H4CH=CH2n-C,
ll9. n-C,1(9 n-C2H40+1 C,2H25 C2tLCH=CHz, CJLCt(=(:l12CH
20CH,,CH20CH.

[:2H40(:B3.C2H,0CH30C2H5,
OC2+15 (:H2CH2CH2C112 CH,,CH3 n-C;3117.n-(:,1I7 i3o-C,tl,, 1SoJ::+1170Ci1
1. ,．． 0C4119 CH2CH=CH2,C+2H□s:H2CJ,CH=
CH□, C21'l<CH=CH2n-C,, B9. n
-C<ll9 n-C+2H□s, n C+2L,.

C2++4C11=C)1□, (:21L(:l1=C
I(□CH□OCH3, Cl□OCI+3 C21140CIlff, C2H, +0CH3n-C,
lIt, n-CJ7 CH2(:H2C82CH2 ■ Compound No.

R, R2 3R4 R1, R6 7RII [I]-(ll8 CI!, O.

[I]-(+19 NO.

[I]-(+20 5bF6 C112CH□0CI(2CH2 CH2C1bCH2Ct12C:l+2CH=C((:
H,)CH2C(CIll)2CH2CLCLOCLC
L CB2CH2CH2CH2CH2 CI=C(CH3)CH2C((:B3)2CH2C)
'l 2 C1120CH2CH2(:H2CLCH2
CLCH2 (:1(=C(CH3)(:82G((:B3)20H
2CH□C1l□OGH□CH2 CH=CH□(JI2CLCI(2 CH-C: (CH,)ell□C(CIL+)tcH2
[I]-(+22 [I]-(+23 CIO.

■ C2H40+1. C21(40H C21(5・C5H7 C6H4Cρ, CJ<0f(:2H5,C:1H7 n-CsH+ I +n-C3HI IC21+ 40
H, C2H40H C2H5,C,H.

n-C:sH++, n-C5! (++C2H4OH,
C2H4011 C211,, CIll7 n-Csl'l+ l, n-C,, ■, +n-(:
5tl+l, n-CJ(,.

[I]-(+26 [I]-(+27 [I]-(+28 [1]-(+29 [I]-(+30 CIO4 bF6 cpo4 5F6 C11□C=CI(, Cll2C:C11(:, H6C
=CI+, (:3H6CmiCHn-C31b, n-03
H7 C6H, CA, C6H4CII CJ5. (:211s CH2(:3CH, C112C3CH 031-1sc=cH, C11C=CHn-CJt, n
-C:+H2 C6114CI! , C6H, CjI C2+15. C2H5 [:112(,:(:H,CH2C:=CHC,H6C
=CHIC3H,C:CH n-C3H,,n-C31(7 06H4Cj',Ca1lnCj' C2H1,C2H9 C112C=CH,CH2C:Cl1 C386C=C11,C31+,C:CHn-C,H,
, n-C3H7 06)1. CP,, C6H4Cρ C211s, CJ (s 678- Compound No.

R, R2 R, R4 R9R6 R2H.

[I]-(32) [I]-(33) F4 n-C3117,n-C:+117 n-C311,n-C:+L Br C2H4CI! , (:J4C1) Cl4(J!, CJJI! [I]-(35) (:RO< [I]-(36) 5bF6 Ct+=C(CH3)CH2C(Cth)2(:l12
Br, Br (:HC(CI-13)CH2C(CI+3)2CH
2n-Cl7. n-C: +H7 n-Cl7. n-C:+[(7 C2H<Cll, C2H<Cll CH3CH3 CIC112CH2CH2CH Ctl=C(Ctl:1) CH2C:(CH:+)2c
t12n-Cl7. n-cJt C11□CH□Ctl. C11□ C21(J:f, (:21+4Cjl'+1.)I CH=C(CH3)CI2(:((:113)2CH2
n-C3H7,n-C3t(y3) The aminium salt compound exemplified in the second paragraph has a maximum absorption wavelength of 90 Or++s or more, and has a large absorption peak with an extinction coefficient ranging from several tens of thousands to about 1000 degrees.

In addition to being used as materials for optical recording media, such infrared absorbing compounds are also used for heat insulating films, sunglasses, and the like.

Further, the infrared absorbing compound of the present invention can be used by being included in an organic dye thin film of an optical recording medium.

Near-infrared absorbing dyes that form organic dye thin films used in combination with these infrared absorbing compounds as optical recording media include -
Pigments known for boat fishing are used, such as cyanine pigments, merocyanine pigments, croconium pigments, and squalium pigments.

These include azulenium pigments, polymethine pigments, naphthoquinone pigments, biryllium pigments, and phthalocyanine pigments.

The amount of the infrared absorbing compound made of the aminium salt compound of the general formula [I] added to these dyes is 1 to 60% by weight, preferably 5 to 40% by weight, based on the total solid content of the recording layer. %, more preferably 10 to 30% by weight.

In addition to these compounds, a binder may be contained in the recording layer consisting of an organic dye thin film. Examples of the binder include cellulose esters such as cellulose dichloromethane, cellulose phosphate, cellulose sulfate, cellulose acetate, cellulose propionate, cellulose acetate, cellulose myristate, cellulose parimitate, cellulose acetate/propionate, and cellulose acetate/acetate. class, methylcellulose, ethylcellulose, propylcellulose,
Cellulose ethers such as butyl cellulose, polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, vinyl resins such as polyvinylpyrrolidone, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene- Acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer,
copolymer resins such as polymethyl methacrylate, polymethyl acrylate, polymethyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyacrylonitrile, polyesters such as polyethylene terephthalate,
Poly(4,4'-isobropylidene phenylene co-)
1,4-cyclohexylene dimethylene carbonate),
Poly(ethylene dioxy-3,3'-phenylene thiocarbonate), poly(4,4'-isobropylidene diphenylene carbonate coated terephthalate), poly(
4,4'-isopropylidene diphenylene carbonate), poly(4,4'-5ec-butylidene diphenylene carbonate), poly(4,4'-isopropylidene diphenylene carbonate-block-oxyethylene)
Polyarylate resins such as polyamides,
Polyimides, epoxy resins, phenol resins, polyolefins such as polyethylene, polypropylene, and chlorinated polyethylene can be used.

Further, the recording layer may contain surfactants, antistatic agents, stabilizers, dispersible flame retardants, lubricants, plasticizers, and the like.

Further, an undercoat layer may be provided between the recording layer and the substrate, and a protective layer may be provided on the recording layer.

As an undercoat layer, solvent resistance is 1! The protective layer is used to protect the recording layer from scratches, dust, dirt, etc., and to provide environmental stability to the recording layer.

The materials used for these are mainly inorganic compounds, metals, or organic polymer compounds. Examples of inorganic compounds include 5i02. MgF2. Sin, TiO2
Examples of metals include Zn, such as ZnO, TiN, and SiN.

Cu, Ni, Ai', Cr, Ge, Se,
Cd etc. can be used, and organic polymer compounds such as ionomer resins, polyamide resins, vinyl resins, natural polymers, epoxy resins, and silane coupling agents can be used.

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

Organic solvents that can be used during coating should be in a dispersed state or
Alternatively, depending on whether it is in a dissolved state, alcohols such as methanol, ethanol, isopropanol, and diacetone alcohol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, N, N
Amides such as dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate, butyl acetate,
Aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene, and benzene.

Aromatics such as toluene, xylene, monochlorobenzene, dichlorobenzene, and aliphatic hydrocarbons such as n-hexane and cyclohexanoligroin can be used.

Coating can be performed using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bee 1 coating method, a wire bar coating method, a plate coating method, a roller coating method, or a curtain coating method.

The thickness of the recording layer formed using such a solvent is 50
Approximately 1100 people, preferably 200 people to 1 ILal.

[Example] Next, examples of the present invention will be described.

Synthesis Example 1. 0.1 mol of 8-diaminonaphthalene, 0.44 mol of P-nitrochlorobenzene, 0.24 mol of anhydrous potassium carbonate
2 parts (by weight) of copper powder was stirred and refluxed for 4 days in 130 parts of dimethylformamide. After the reaction, the reaction mixture was filtered, and the resin was thoroughly washed with dimethylformamide, water, and acetone, and then dried.

Reddish brown tetrakis (P-nitrophenyl)-8 9 27 parts of 1,8-diaminonaphthalene were obtained.

1-25 parts of the compound obtained as described above were added into an autoclave together with 95 parts of dimethylformamide palladium-carbon hydrogenation catalyst and 2 parts, and hydrogen gas was applied at 5.0 kg/cm2 at 90°C to 100°C to absorb hydrogen or IF. The whole mixture was stirred.

After the reaction, the reaction solution was filtered and the furnace material was poured with dimethylformamide 1
After washing it, it was placed in 34 parts of iced water. After stirring for a while, the precipitate was poured into a furnace. Recrystallization was performed using an ethanol dimethylformamide mixed solvent to obtain 10 parts of tetrakis(p-aminophenyl)-1,8-diaminonaphthalene. Purity was measured by high performance liquid chromatography and found to be 98.5%.

3 parts of the amino compound described above were heated and stirred at 100°C to 130°C with 18 parts of dimethylformamide, 0.6 parts of anhydrous sodium bicarbonate, and 3.8 parts of n-propyl bromide. After 36 hours of reaction, the reaction solution was poured into 1.00 parts of ice water,
Extracted with ethyl acetate. After drying, it was purified using a silica gel column. The amount acquired was 3.2 copies. Disappearance of absorption due to NH stretching vibration of the amino group was confirmed by infrared absorption analysis.

One part of this compound was dispersed in 20 parts of acetone, and the equimolar amount of silver perchlorate was added while stirring. After reacting at room temperature for 1 hour, the precipitated silver was separated in a furnace, the furnace solution was diluted with isopropyl ether and allowed to stand, and the precipitated crystals were taken out on a furnace plate. The amount obtained is 0
．． There were 7 copies.

Compound 5iIRNo, [IF(5
) is absorption maximum wavelength 1060 n Il + extinction coefficient 37,
It was a compound with a large absorption region in the infrared region of 0.000.

In the example explained above, the anion is perchloric acid, but if another anion is used, the desired compound can be easily obtained by using the corresponding silver salt. For example, Ag5bF.

AgBFn, Ag5O<, AgNO3, Ag5O,
, Cs11. Silver salts such as Cl-13 and Ag5036F:+ can be used. In addition, it can also be obtained by electrolytic oxidation.

Compound No. “Synthesis of [I]-(17)” 1214
4 parts of 7 bodies were heated and stirred at 100°C to 130°C with 240 1 parts of dimethylformamide, 1.0 part of anhydrous sodium bicarbonate, and 4.0 parts of 2,5-dibromohexane. After reacting for 37 hours, the reaction solution was poured into 120 parts of ice water and extracted with ethyl acetate. After drying, it was purified using a silica gel column. The amount obtained was 3.7 copies. Disappearance of absorption due to NH stretching vibration of the amino group was confirmed by infrared absorption analysis.

0.8 parts of this compound was dispersed in 15 parts of acetone, and the equimolar amount of silver hexafluoroantimonate was added while stirring. After reacting at room temperature for 1 hour, the precipitated silver was separated in a furnace, the furnace solution was diluted with isopropyl ether and allowed to stand, and the precipitated crystals were collected. The amount obtained was 0.5 part. Moreover, the maximum absorption wavelength was 11070n.

Next, an example will be described in which an infrared absorbing compound represented by the general formula [IF is used as an optical recording material.

Example 1 Diameter 1. : 1Om+sφ, thickness 1.2+sl polymethyl methacrylate (hereinafter referred to as PMMA) substrate with a 50p pregroove (IR-820 manufactured by Nippon Kayaku) organic dye and the infrared absorbing compound No. [I]-(5) was dissolved in 1,2 dichloroethane at a weight ratio of 80:20 to form a recording layer of 900 layers by spin coating. The medium thus obtained has an O. : A 1 mm spacer was sandwiched between the substrate and another PMMA substrate was bonded with an ultraviolet curable resin adhesive to obtain an optical recording medium having an air sandwich structure.

This was rotated at 1.800 rpm, and using a semiconductor laser with a wavelength of 830 nm, the recording power was 6 mW from the substrate side.
, recording frequency 2MH7. I wrote this. Next, reproduction was performed with a read power of 0.8 mW, and the C/N ratio was measured by spectrum analysis. Subsequently, the C/N ratio was measured after 100,000 readings and reproductions.

Furthermore, the optical recording medium prepared under the above conditions has an I KW/m
A tip stability test was conducted by irradiating the sample with xenon lamp light of No. 2 for 100 hours, and the reflectance and C/N ratio were measured. The results are shown in Table-1.

2 3 Table-1 Table-2 Example 2 l-guaiazulenyl-5-(6'-tbutylazulenyl)-2,4-pentageno A recording layer was formed using a liquid containing -J perchlorate and the infrared absorbing compound No. [I]-(17) in a weight ratio of 90:10.

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

Examples 3 to 7 In the same manner as in Example 1, optical recording media having the compositions shown in Table 3 were prepared, and the same tests as in Example 1 were conducted. The results are shown in Table 4.

4 5 Table-3 Real 1,5-diguaiazulenyl-2,4-pentagenol perchlorate-8 90:10 (p-dimethylaminophenyl)-(p-ethoxyphenyl)methylene-1 -cyclopent-2-2-3-(p-dibutylaminophenyl)-(p-ethoxyphenyl)carbonium perchlorate 85:15 1.5-bis(dimethylaminophenyl)-1,5-diphenyl-2, 4-Pentagenol perchlorate -14 80:20 6 1.1'-dimethoxyethyl-I -2575:
253.3.3',3'-tetramethyl-2,2'-indotricarbocyanine perchlorate 7 NK-1414 (Japanese photosensitive dye type) I-31
70: 30 Comparative Examples 1 to 3 Optical recording media were prepared and evaluated in the same manner as in Examples 1, 2, and 5 except that the infrared absorbing compound used in Examples 1, 2, and 5 was omitted. The results are shown in Table 4.

Table-4 27,6 25,3 25,8 35,5 32,1 21,8 22,3 21,4 30,1 21,9 25,1 7 1 13,1 5 27,5 7 0 14,2 4 26, 2 4 8 12, 9 2 Example 8 - A pre-croup was formed on one OLED-sized polycarbonate (hereinafter abbreviated as rPcJ) substrate with a thickness of 0.4 mm by a heat press method, and then A solution prepared by mixing an organic dye and an infrared absorbing compound shown in Coating 5 below in diacetone alcohol was coated by the Harney 1~ method and dried to obtain a recording layer of 850 people. Furthermore, that'
Second, an optical recording medium having a close contact structure was prepared by bonding a two-dimensional 0.3 mm thick PC substrate with an ethylene-acetate Vitri film by a hot roll method.

The optical recording medium of each example produced in this way was mounted on a stage driven in the X-Y direction, and a semiconductor laser with an oscillation wavelength of 830 nm was used to deposit the organic thin film recording layer from the PC board side with a thickness of 0.4 cm. Information was written in the Y-axis direction with a recording power of 4.0 mm and a recording pulse of 80 g, 5 ec, and reproduced with a read power of 0.4 mm, and the signal strength (B→signal strength of the recording part) was measured.

Furthermore, the same optical recording medium produced under the above conditions was used in Example 1.
A light resistance stability test was conducted under the same conditions as above, and the reflectance and contrast ratio were then measured. The results are shown in Table-6.

Table-5 IR-820 (manufactured by Nippon Kayaku) -6 85:15 (p-dimethylaminophenyl)-(p-ethoxyphenyl)methylene-1-cyclopenten-2-yl-3-(p-dimethylaminophenyl) -(p ethoxyphenyl) carbonium perchlorate ■ 2 90:1.0 0 1.5-bis(dipropylaminophenyl)-] , ]5-diphenyl-2,4-pentacyenol perchlorate ■ -28 85: 1.5 1 1-guaiazulenyl-5,5-bis(dimethylaminophenyl)-2,4-pentadienol perchlorate -35 70:30 8 9 Comparative Examples 5, 6 Infrared absorption in Examples 8 and 10 Optical recording media were prepared and evaluated in the same manner as in Examples 8 and 10, except that the compound was omitted. The results are shown in Table-6.

Table 6 After the initial light resistance test, when the above-mentioned infrared absorbing compound is contained in the organic dye thin film and used as an optical recording medium, the optical recording medium has significantly increased durability and light resistance stability during repeated reproduction. It became possible to obtain.

Claims (2)

[Claims] (1) An infrared absorbing compound represented by the following general formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (In the formula, R_1 to R_8 represent a hydrogen atom, a halogen group, or a monovalent organic residue. R_1 to R_8 may be different or the same. Also, R_1 and R_2
, R_3 and R_4, R_5 and R_6 and R_7 and R_
A combination of 8 may form a 5-membered ring, a 6-membered ring, or a 7-membered ring. X^■ indicates an anion. ) (2) An optical recording medium comprising an organic dye thin film containing an infrared absorbing compound represented by the general formula [I] according to claim 1.