JPH0248991A - Optical recording medium - Google Patents

Abstract

PURPOSE:To enhance sensitivity to light in a near infrared region and enhance improve durability by providing an organic thin film comprising a naphthalocyanine compound of a specified general formula as a main constituent on a base, thereby producing an optical recording medium. CONSTITUTION:A naphthalocyanine compound of formula I [M is two hydrogen atoms or a Ia, IIa, IIIa, IVa or Va group element, each of Y1 and Y2 is a halogen, hydroxyl or the like, at least one of R1, R2, R3, R4, R5, R6, R7 and R8 is an aminoalkoxyl of formula II (Q is a 1-18C alkyl, each of R9 and R10 is hydrogen, a 1-10C alkenyl, cycloalkenyl or the like), X is hydrogen, a halogen or the like, and n is an integer of 0-4] is dissolved in an organic solvent to prepare a coating liquid. The coating liquid is applied to a base, followed by drying to produce an optical recording medium having an organic thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical recording medium, particularly an optical recording medium having an organic recording layer for a semiconductor laser having absorption in the near-infrared region.

(Prior Art) In recent years, the development of conductor lasers has been remarkable, and small and stable oscillators have become available at low cost and have begun to be used as light sources for various recording devices. However, the wavelengths of these semiconductor lasers are limited to relatively long wavelengths, and semiconductor lasers capable of oscillating short wavelength light have problems in terms of lifespan, output, etc.

Therefore, as a recording medium for semiconductor lasers, it is essential to use a material that absorbs in the near-infrared region as a thin film layer.
Materials with a maximum absorption wavelength of 750p or less are unsuitable.

Conventionally, in this type of recording medium, there is one in which a thin film formed on a substrate is irradiated with laser light to form pits, and recorded information is read out based on the difference in reflectance between pits and non-pit areas. The structure of the recording layer for recording and reproduction (reading) consists of two layers: a recording thin film forming layer and a reflective film.
Although there are some with a layer length of L, a 4T type has only a recording thin film layer and has both of the above functions. In the case of a single-layer film for this recording thin film layer, it is essential that the material of the recording thin film layer itself has a high reflectance in order to obtain a high CZN ratio. As this type of recording medium, inorganic ones using a low melting point metal such as To or its alloy are known, and organic ones using cyanine dyes and phthalocyanine compounds are known.

(Problem M to be solved by the invention) Inorganic optical recording media using Te-based alloys have relatively high sensitivity, but they have problems with monolithicity, and the film formation method uses sputtering, etc., so equipment costs are high. However, they suffer from the disadvantages of high productivity and low productivity. Organic thin-film optical recording media using cyanine dyes have the advantage of being able to be produced using relatively inexpensive methods such as the spin-coding method, but they are not as good in terms of performance, such as storage stability (durability). The current situation is that it has not reached its potential. Furthermore, in the case of naphthoquinone and anthraquinone, they have poor solubility in solvents and have storage stability problems such as the formation of agglomerated structures. Furthermore, in the case of phthalocyanine compounds, solvent solubility, conductor laser matching properties, and retention were insufficient due to changes in the crystals inside.

(Means for solving the problem) For recording and reproducing optical recording media that are highly sensitive to light in the near-infrared region, have high solvent solubility, high reflectance, and are nontoxic (and have excellent durability). In order to provide a thin film material and thereby provide an excellent optical recording medium, the present invention has been arrived at as a result of intensive studies.That is, the present invention is based on the L component of a naphthalocyanine compound represented by the following general formula [1]. This is an optical recording medium characterized by forming an organic thin film on a substrate.

(where M is two hydrogen atoms or IasIIaxII[
allVax Va1VIax■a1■, Ib, IIb
.

mb, ■b1vb, vxb, ■represents a b group element, y
, , Y2 is a halogen atom, hydroxy group, or oxygen, R,, R2, R,, R,, R5, R,, R7, R8
is at least one of the general formula / 0-Q-N \ (wherein, Q represents a straight chain or branched alkyl group having 1 to 18 carbon atoms, N Rn and Rto may be the same or different, Hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, a cycloalkenyl group having 1 to 10 carbon atoms, an allyl group, an aralkyl group, or R
9 and RIO are bonded through a carbon atom or a heterogen f to form a 3- to 7-membered heterocycle with the nitrogen atom in the general formula), and other The substituents may be the same or different;
(n represents an integer of 0 to 4) The optical recording medium in which the specific naphthalocyanine compound of the present invention is formed as a thin film on the substrate 1- is capable of titrating sensitivity, reflectance, and durability in the near-infrared region. It is useful as a recording medium for iIT students using various types of media such as optical discs, optical cards, and tapes.

As long as the object of the present invention is not impaired, the naphthalocyanine compound may be used in combination with a stabilizer, a lubricant, an antistatic IL agent, a polymer compound as a binder, other dyes, and a sensitizer. The substrate material used in the present invention may be either transparent or opaque to the laser beam used, but if old recording is to be performed using the laser beam from the substrate side, it must be transparent to the laser beam.

Examples of these substrate materials include glass, acrylic resin, methacrylic resin, polyester resin, nitrocellulose resin, polyamide resin, polycarbonate resin, polymethylpentene-1 resin, epoxy resin, vinyl chloride resin, polyvaraphenylene resin, etc. . These resins are shaped into sheets, films, disks, etc., and these shaped objects may be coated with a coating layer or a layer coated with a specific metal as required. You can.

This will be explained in more detail below using the F1 embodiment.

In addition, the measurement and evaluation of the characteristics in the examples were performed in accordance with the description given below.

A spectral naphthalocyanine compound was dissolved in ethanol to a concentration of 1.5%, and a 70 nm thin film was formed on a glass substrate using a spin coater. The absorption and reflection spectra of this were measured using a UV-VIS spectrometer (Shimadzu UV21 OA). From this, the reflectance of 830nT11 (R%
) was sought.

The recording medium obtained by aEJkJLJL was irradiated with an 830+ym semiconductor laser at an optical power of 7 mW and a lens diameter narrowed to IP to write in the concave portions of the tracks.

Next, the same laser light source (0.5 mW) was used as a readout light, and the cut-in light pulse width at which the C/N ratio of the reflected light was 50 dB or more was measured, and the reciprocal of the sensitivity was calculated.

The reflectance and C/N ratio were measured after irradiating a 1U recording medium at 63° C. for 300 hours using a Cyshine carbon arc fade meter, and the deterioration was found to be 118%.

The reflectance and C/N ratio were measured when the recording medium obtained in Example 11 was stored at 70° C. and 90% RH for 3 months.

1.5 g of naphthalocyanine compound was placed in a test tube with a single stopper, ethanol was added, and after the stopper was tightly closed, ultrasonic waves were applied for 30 minutes at 60°C to dissolve.Then, the mixture was brought to room temperature for 1 hour. After standing, it was filtered and the soluble content was measured to determine the solubility.

(Example) A naphthalocyanine compound corresponding to each experiment described in F was dissolved in ethanol and coated onto a glass substrate [-] to a solid content thickness of 70 nm using a spin coater. f
Various properties and performance of each sample were evaluated. The Song Dynasty is shown in Table-■.

No.

〔Example〕

No.

〔Example〕

■, O(CH2)2N(C4H9)2H3 No.

〔Example〕

■, -〇-+CH2)2N(C2H5)2No.

〔Example〕

■ 10-+CH2)6N(CH3)2 No.

[Comparative example]

No.

[Comparative example]

■-8O□NH-(CH2)jiOC2□H45■-〇
(CH2)N(CH3)2 ■ NHCO 2H5 No.

[Comparative example]

(Effects of the Invention) An optical recording medium in which a thin film containing a specific naphthalocyanine compound as a main component of the present invention is formed on a substrate has a good balance, and furthermore, the medium has excellent durability. On the other hand, even if it is a similar natsutaloncyanine compound, if it is not represented by the general formula of the present invention, it will meet the requirements in L and various properties as an optical recording medium. , it was found that either one of them was inferior and that it was of little practical use.

Special client: Toyobo Co., Ltd. Tokugibo Seto Hongri Pharmaceutical Co., Ltd. 1 Kizuna Shiki Shokusha

Claims (1)

[Claims] (1) An optical recording medium characterized in that an organic thin film containing a naphthalocyanine compound represented by the following general formula [1] as a main component is formed on a substrate. [1] Formula, ▲Mathematical formula, chemical formula, table, etc.▼ (In the formula, M is 2 hydrogen atoms or Ia, IIa, IIIa,
IVa, Va, VIa, VIIa, VIII, I b, IIb, IIIb
, represents an element of group IVb, Vb, VIb, VIIb, Y_1,
Y_2 is a halogen atom, hydroxy group, or oxygen,
R_1, R_2, R_3, R_4, R_5, R_6, R
At least one of _7 and R_8 is a general formula, ▲a mathematical formula, a chemical formula, a table, etc.▼(In the formula, Q is a straight or branched alkyl group having 1 to 18 carbon atoms, and R_9 and R_1_0 are the same or different. may be different, hydrogen atom, carbon number 1 to 1
0 alkyl group, cycloalkyl group having 1 to 10 carbon atoms, alkenyl group having 1 to 10 carbon atoms, cycloalkenyl group having 1 to 10 carbon atoms, allyl group, aralkyl group, or R_9 and R_1_0 are carbon atoms or hetero atoms , and together with the nitrogen atom in the general formula, 3
represents an aminoalkoxy group represented by (indicating that it forms a 7-membered heterocycle); other substituents may be the same or different; (represents a straight-chain or branched alkoxy group, X represents an elementary atom, a halogen atom, a nitro atom, and n represents an integer from 0 to 4)