JPS60226035A - Additional recording type optical recording medium - Google Patents

Abstract

PURPOSE:To enable recording with low energy and to prolong the shelf life by forming a recording layer consisting of coloring matter having a specified structure and polyvinyl butyral resin. CONSTITUTION:The recording layer consisting of coloring matter having a structure represented by the formula and polyvinyl butyral resin is formed. In the formula, Y is -H, -SO3<->, -SO3H, -SO3Na or -SO3K, l is an integer of 1-4, Y' is -H, -SO3H, -SO3Na or -SO3K, n is an integer of 1-4, m is 3 or 4, X<-> is a halogen ion or a univalent anion represented by ClO4 or BF4, and when Y is -SO3<->, X<-> is not present. An additional recording type optical recording medium having the formed recording layer enables recording with semiconductor laser having <=5mW low output, and degeneration in a wet environment can be considerably reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat mode recordable optical recording medium ζ2 in which a portion irradiated with a laser beam is ablated to write a recording signal.

[Background technology]

In recent years, with advances in laser technology62, optical recording systems that record and reproduce information using laser light have been in the spotlight.

Optical recording systems can record information at high density (2), retrieve recorded information at any high speed (2), and read out information without contact, making the recording medium highly durable. It has been cited as having advantages over conventional magnetic recording C, such as:

The optical recording system C2 is a playback-only type that has already been put into practical use as a video disc and digital audio disc, a write-once type that allows the user to record and play back any information, and a write-once type that allows the user to record and play back any information. However, there are rewritable types that can record other information, but the present invention relates to the write-once type optical recording system 62, which is a recording medium such as a document file or a computer external memory.

As a recording method in a write-once optical recording system, a laser beam is focused and applied to a recording layer on a recording medium.
;How to form minute irregularities and bubbles, and light transmittance9
There are methods such as changing the reflectance, etc., and various optical recording media have been proposed from the viewpoints of higher recording sensitivity, lower noise, longer storage life, etc.

Currently proposed recording media are broadly divided into (a) those having an inorganic thin film typified by a low melting point metal such as tellurium as a recording layer, and (b) those having an organic dye as a recording layer.

However, in any case, there is a current situation C2 in which improvement is desired from the viewpoint of an optical recording medium that can be recorded with high sensitivity, that is, with low energy, and has a sufficiently long shelf life.

[Disclosure of the invention]

As a result of intensive studies to satisfy these demands, the inventors of the present invention have found that by using a recording layer made of a specific organic dye and a specific binder, recording with high sensitivity, that is, low energy, and a long shelf life can be achieved. C2 has been developed to invent a new and improved write-once optical recording medium.

That is, the write-once optical recording medium according to the present invention has the following formula: (4) General formula (1) [In formula (I), Y bar H, -8058-8O5H, -
8O5Na Matah-8OIIK, t is an integer from 1 to 4, Y' is -H% -8O'H1SO3Na or -8O5K, n is 1 and P does not exist]
It has a recording layer made of a dye having the structure and (B) polyvinyl butyral resin.

[Best mode for carrying out the invention]

Examples of the dyes used in the present invention include dyes having the following structural formulas, and are not limited to these, and are not limited to the above-mentioned general formula (I). The dyes may be used in different colors, or two or more of these dyes may be used in combination.

The dye (4) above has a wavelength range C of 700 to 11,000 nm, which corresponds to the oscillation wavelength of a semiconductor laser; it has strong absorption, and when irradiated with laser light, it generates heat, causing the laser irradiated part of the recording layer to melt or Decomposition occurs and unevenness is formed.

The polyvinyl butyral resin (B) above is a resin having a cyclic ether structure on the side nl2 obtained by the reaction C2 of polyvinyl alcohol and n-butyraldehyde or isobutyraldehyde, and has a strong recording layer film with no stickiness. It is a binder for the above-mentioned pigment to form.

The above dye (4) has good absorption of laser light and is suitable for increasing the sensitivity of recording media. However, it has poor durability (C2) under humidity-resistant conditions (2), and therefore has a major drawback in terms of long-term storage. However, by using the polyvinyl butyral resin of CB) above as a binder component 6: Therefore, the durability under humidity-resistant conditions has been significantly improved. Since the recording layer has good properties, it also has the characteristic that no aggregates of the C di-dye are formed in the recording layer.

A part of the polyvinyl butyral resin (B) above, which is a binder component, is mixed with other resin binders that are compatible with the polyvinyl butyral resin, such as nitrocellulose, polyvinyl formal, polyvinyl alcohol, alkyd resins, etc., and dioctyl phthalate, dibutyl separate, etc. It is also possible to use it in place of a plasticizer such as , tricresyl phosphate, etc., but the binder component 5
It is preferable that 0% by weight or more, especially 70% by weight or more, be polyvinyl butyral.

The mixing ratio of the dye (a) and the binder component in the recording layer is such that the dye accounts for 5 to 80% by weight in the recording layer, and the remaining portion is a binder component whose main component is polyvinyl butyral (a). If the amount of the dye (4) is less than 5% by weight, the recording sensitivity will not be sufficient, and if it is more than 80% by weight, the durability in a humidity-resistant environment C will be greatly reduced.

In particular, it is preferable that the dye content in the recording layer is 10 to 60% by weight.

The binder component mainly composed of the above-mentioned dye and the polyvinyl butyral resin of 03) is dissolved in an organic solvent that dissolves both and removes insoluble matter by filtration according to the necessary C2, and then A recording layer is formed by coating by a method such as varnish spin coating.

Examples of organic solvents that dissolve both of them include methanol, alcohol, ethylene glycol monomethyl ether,
One type or a mixture of two or more of dimethylformamide, dimethylacetamide, cedarime, etc. is used, but other solvents may be mixed and used as long as the solubility of the solvents is not inhibited.

As the recording medium substrate on which the recording layer is applied, for example, methacrylic resin, polycarbonate resin, polyester resin,
A sheet or film made of gelastec such as polyvinyl chloride resin or styrene copolymer resin, an inorganic material such as glass, or a metal plate with a mirror surface is used, and even if a reflective layer is formed in advance on the substrate, it is also possible to Grooves and recording position indicating signals may be formed in advance.

The thickness of the recording layer is usually 0.2 to 5 μm, and 0.5 to 2 μm.
m is preferred. Also, if the above substrate is transparent,
Further, metal vapor deposition such as 6 Ni aluminum may be applied on the recording layer. The write once optical recording medium of the present invention obtained as above is
A spot beam of 1 μm or less, such as a semiconductor laser beam, with an oscillation wavelength in the range of 700 to 11,000 nm (2) is focused and irradiated onto the recording layer, melting and decomposing the recording layer to write a concave-convex signal, and a weaker laser beam is used. The above-mentioned unevenness signal is read out by picking up the unevenness signal, and the image, audio, etc. are converted and reproduced according to the IJs.

〔Effect of the invention〕

The write-once optical recording medium of the present invention is capable of recording using a low-output semiconductor laser of 5 mW or less, and is capable of recording in a moisture-resistant environment (
I was able to improve the alterations in the two by a large margin (two).

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 Dye 10f and polyvinyl butyral resin 40? After dissolving 4502 in methanol and filtering it through a cartridge type filter, the P solution was applied to a polycarbonate resin substrate C with a thickness of 1.2 m and a diameter of 120 pieces with aluminum vapor deposition on one side using the varnish bottle coating method, and dried to a thickness of 0. .4μm
An optical recording medium of the present invention was obtained by forming a recording layer.

As a result of writing and reading signals using an optical head with an automatic focus control mechanism equipped with a semiconductor laser with an output of 15 mW that emits an oscillation wavelength of 830 nm,
It was possible to write and read signals at a position with a radius of 50 ropes and a rotational speed of 1800 rpm.

After leaving the recording medium on which the above signals were written in a constant temperature chamber at 50°C and 90% relative humidity for 500 hours,
I then read out the signal and was able to get the same signal output as before the humidity test.

Example 2 Exactly the same except that the width of the polyvinyl butyral resin 40f used in Example 1 was replaced by 30F of polyvinyl butyral resin and 10f of nitrocellulose. 1 of the signal under similar conditions
I was able to read and write data. Also, Example 1
I read out the signal after the humidity test in the same way as above, but
The same signal output as before the humidity test was obtained.

Example 6 In place of the dye used in Example 1, a dye having 15F, 30 tons of polyvinyl butyral & fat, 5 tons of nitrocellulose, and 200 ml of ethanol were added. , Methyl Cellosolve 250f (250f) was dissolved, filtered through a cartridge type filter, and the filtrate was used in the same manner as in Example 1 to obtain an optical recording medium of the present invention having a recording layer of 0.3 μm.

Signals could be written and read under the same conditions as in Example 1. Further, when the signal was read out after the humidity test using C2 in the same manner, the same signal output as before the humidity test was obtained.

Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. (A) General formula (1) [In formula (1), Y is -H, -805, -8O5H, -8
O5Na or -8O3, t is an integer of 1 to 4, Y is -H% -8O5H, -8O5Na or -8O5, n is an integer of 1 to 4, m is 3 or 4 is an integer, and 0 is a halide ion, C/J
)4 or BF4, is a monovalent anion represented by O, and when Y or -S06..., Xo does not exist. A write-once optical recording medium having a recording layer made of a dye having the structure: and (B) a polyvinyl butyral resin.