JPS5962188A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium favorable in film coating property, having a high S/N ratio when reading accompanied by little reproduction deterioration, provided with a recording layer consisting of a polymer having a phthalocyanine residue in a side chain. CONSTITUTION:The objective optical recording medium comprises the recording layer consisting of a polymer having a phthalocyanine residue in a side chain, wherein the benzene ring of phthalocyanine is bonded to the benzene ring of a styrene unit in the skeleton of the polymer, preferably a styrene polymer, through a connecting group such as -CO-. EFFECT:Phase separation, migration of a coloring material and bleeding are prevented from occurring, concentration of the coloring material can be enhanced, and writing sensitivity and recording rate are enhanced.

Description

[Detailed description of the invention] ■ Background of the invention Technical field The present invention relates to a heat mode optical recording medium.

Prior art and its problems Optical recording media have the characteristics that the recording medium does not deteriorate due to wear and tear because there is no contact between the medium and the writing or reading head.For this reason, research and development of various optical recording media has been carried out. ing.

Among such optical recording media, heat mode optical recording media are being actively developed because they do not require image processing in a darkroom.

Such a heat mode optical recording medium is an optical recording medium that uses recording light as heat, and a part of the medium is melted or removed using laser recording light to form small holes called pits. However, there are devices that record information using these pits and detect the presence or absence of these pits using readout light.

As an example of such pit-forming media,
It is known that a recording layer made of a thermoplastic resin and a dye as a light absorber is coated, and the resin is melted to form pits.

In addition, such a medium has the following features according to the present invention: [According to research, it is possible to erase once formed bits with erasing light or heat to flatten the entire or part of the surface of the recording layer and write again. has been confirmed.

By the way, such conventional media have a recording layer of a thermoplastic resin and a dye that are compatible with each other or pre-filled yarns. Therefore, phase separation, pigment migration, bleeding, reagglomeration, etc. are likely to occur in the recording layer.

These problems occur because the dye concentration is high (which is likely to occur), so it is not possible to increase the dye concentration in the recording layer, resulting in a low recording rate, low writing sensitivity, and low reading S/N ratio. There are drawbacks.

In order to overcome these drawbacks, research by Inventor et al. has revealed that it is sufficient to form the recording layer using a thermoplastic resin carrying a dye, and we have previously described this point. However, 1. One of the pigments that is stable against heat, light, etc.
As one example, phthalo/anine dyes such as Golden Maple Phthalocyania are known.

Therefore, if a recording layer is formed using a thermoplastic resin containing a phthalocyanine dye, it is expected that an optical recording medium with extremely good characteristics will be realized.

However, for example, j(, 1 jin 5choch, Jr et
al.

J, Amer, Chern, Soc, 101.7071
．． (1979), Meyer et al.
, Makromor, Cbem, .

176, 1919 (1975) and J, B, 1)a
vison etal, Makromolecule
Polymers containing metal phthalocyanine, such as those described in es*II +186+ (1978), have poor coating properties and low readout S/N ratios, which vary depending on location, and the S/N ratio due to repeated irradiation with readout light. There is a drawback that the reproduction deterioration of the N ratio is also large.

■ Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and its main purpose is to provide good film properties and readout S
An object of the present invention is to provide an optical recording medium having a recording layer made of a polymer containing a phthalo/anine dye, which has a high /N ratio and little reproduction deterioration.

Such objects are achieved by the invention described below.

That is, the present invention is an optical recording medium characterized by having a recording layer formed from a polymer having a phthalocyanine residue in a side chain.

■Specific 4R composition of invention EMBODIMENT OF THE INVENTION Hereinafter, the specific structure of this invention will be explained in detail.

In the present invention, the polymer has a phthalocyanine residue in its side chain.

1. C, that is, a phthalocyanine residue is bonded from the main chain or side chain of the polymer to the side chain, if necessary, via a linking group.

In this case, there are no restrictions on the polymer skeleton, linking groups, etc.
Although various materials such as polyamide, polyurethane, polyester, and silicone may be used, the polymer skeleton is preferably a vinyl polymer having one vinyl monomer unit from the viewpoint of ease of synthesis. In particular, if a styrene/styrene copolymer having styrene units, that is, a styrene polymer is used as a backbone, it is easy to synthesize, has high reflectance, high solubility, and has chemical and physical properties. It has the advantages of high physical stability, low cost, non-toxicity, and good moisture resistance and microbial resistance.

Similarly, when the skeleton is a styrene polymer, the phthalocyanine residue is preferably bonded to the be/zene ring of the styrene unit via a suitable linking group.

In such a case, it is preferable that the bond of the phthalocyanine residue be present in the base/base of the phthalocyanine ring.

In addition, it is preferable to form the linking group 2 by bonding a functional group that has been introduced in advance to the notarocyanino residue in the styrene base, so 'i'5'
vc, in that it uses the Freechill-Crafts reaction -
C (preferably a J- group. /, C, and other linking groups include -Nl-1-, -0-, -C(X)
-, -C0N) -1-isomoaJ, &, 6゜On the other hand, there are no particular restrictions on the center of phthalocyanine,
Even in the case of H, P, 1-, and notarocyrnia are usually preferably gold J/13notalonfine from the point of view of absorption wavelength, and the central metal atom is l, i
, Na, K, Be.

84S' + (-;l + L)I
' + ) J, + l SC, Y
+La r i'l +Zr,
IH, V, Nb, 'I'a, Cr, Mo
, W, Mn.

'I''c, ['Le, Fe, I(u,
Us, Co, I: Lh, Ir.

Ni, I)b; PI, Cu, Aj,
Au, Cd, Hy.

At, (3a, In, Tt, Si,
Ge, Sn, Sb.

Te, Ce, Nd, Sm, Eu,
Gd, Tb, Ho.

It may be. Further, other ligands may be further coordinated to the central metal atom from above and below the phthalocyanide/ring.

In addition to the above-mentioned linking groups, the benozene ring of phthalocyanide) also includes a nitro group, a carboxylic acid group, a halogen atom, an amine group to which an alkyl group or an aryl group may be bonded, an alkyl or arylcarbamoyl group, An alkyl or aryloxycarbonyl group, an acid chloride group, etc. may be bonded.

Approximately 0 to 7 such substituents are contained in the molecule.

Examples of polymers include copolymers of styrene and 2-vinylpyridine, 4-vinylpyridine, acrylic esters, methacrylic esters, acrylonitrile, butadiene, vinyl acetate, and the like.

In addition, when the skeleton is a styrene copolymer, there is no particular restriction on the copolymerization ratio, and usually JO
The copolymerization ratio is set to about less than molar. Further, the copolymer may be a random polymer or a block or graft polymer. Furthermore, there is no limit to the average number of repeating units in the styrene polymer.

Furthermore, the content of 7-thalocyanine residues in the polymer is usually about 0.1 to 100 mol% of the number of repeating units.

Such polymers of the present invention may be polymerized after bonding a metal phthalocyanide to one monomer unit, but usually, after forming a polymer skeleton, polymerization is carried out according to a conventional method as necessary. A phthalocyanine is bonded to the skeleton via a linking group.A specific synthesis method when using a styrene polymer as the polymer skeleton is 1Malcromol.

Chen, 180 2073-2084 1.979
Ya, Polymer Preprints, Ja
It is described in Pan 30 14801981 etc.

Next, specific examples of polymers will be given, but the present invention is not limited to these.

In addition, in the following, M represents the central metal atom of phthalocyanine, and 1( represents a substituent bonded to the pen/zene ring of 7 thalocyanine/ring.

The recording layer in the present invention is thus formed commercially from a polymer.

In order to form such a recording layer, it is generally sufficient to form a film according to a conventional method, and the thickness thereof is generally 0.01 to 10
It is said to be about μrn.

In addition, such a recording layer may contain other polymers or oligomers, various plasticizers, surfactants, antistatic agents, lubricants, flame retardants, stabilizers, dispersants, leveling agents, antibleeding agents, visible Light absorber, ultraviolet absorber, infrared scarlet absorber, antioxidant, water repellent, solubility improver, emulsifier, antifoaming agent, polishing agent, anti-slip agent, softener, slagging improver, pinhole prevention agent It may also contain agents such as Yuzu bile duct inhibitor, antimicrobial agent, etc.

On the other hand, the substrate for supporting such a recording layer is not particularly limited, and various materials can be used for the substrate.

However, in terms of thermal conductivity, surface properties, mechanical strength, hygroscopicity, adhesiveness, etc., various types of glass, various types of tempered glass, various types of ceramics, polymethacrylic resin, polyacrylic resin, polycarbonate resin, phenolic resin, and epoxy resin are generally used. resin, diallylphthale) [4 resins, polyester resin, polyimide resin, polyether zulfone, polyether keto/, methyl pente/polymer, polyester resin, polyolefin, polyphenylene/sulfide, nylon, fluorine resin, etc. It is preferable to use

Further, the shape and dimensions of the base body can be various depending on the intended use, such as a disk, tapered belt, or drum tube.

In this case, the medium of the present invention may have the above-mentioned recording layer on one surface of such a substrate, or may have recording layers on both surfaces thereof. In addition, two recording layers are coated on one side of the substrate, and the recording layers are made to face each other with a natural gap between them, which is then sealed tightly to prevent dust and scratches. You can also do it like this.

In addition, in the above-mentioned medium, a subbing layer such as a metal reflective layer or various resin layers is provided on the substrate as necessary, and this subbing layer -
A recording layer can also be provided on L. As other subbing layers, coating layers of various thermoplastic resins, thermosetting resins, ultraviolet rays or electron beam curable resins, etc. can also be used.

Furthermore, a reflective layer, a subbing layer, and a recording layer can be formed in this order on the substrate.

Further, it is also possible to design the recording layer to be thick and non-reflective.

In addition, a guide groove may be provided in the substrate, and a recording layer may be provided on the protrusion and/or in the recess of this groove.

Furthermore, a reflective layer, an anti-transmissive film layer, a protective layer, etc. can be provided on the recording layer, if necessary.

(2) Specific Effects of the Invention The medium of the present invention is generally irradiated with recording light that is focused in a predetermined manner in a pulsed manner while the medium is running. At this time, due to heat generated by the phthalocyanine residue in the light-absorbing polymer in the recording layer, the polymer itself melts and deforms, forming pits.

The pits formed in this manner are read out by detecting the reflected or transmitted light of the readout light while the medium is running.

On the other hand, the pits formed in this manner can be erased and rewritten after forming bits.

In such a case, erasing may be carried out by heating the whole or a part of the medium, or by irradiating the whole or a part of the medium with erasing light. It is also possible to perform line erasing by scanning the erasing light while the medium is running.

By such irradiation with erasing light and heating, the recording layer in the pit-formed portion is melted and flattened, and writing can be performed again.

Such erasing and rewriting can be repeated many times.

■Specific Effects of the Invention Since the recording layer of the present invention is composed of the above-mentioned polymer, phase separation, migration/bleeding of the dye does not occur, the dye concentration can be increased, and the writing sensitivity and Recording rate improves.

In addition, there is little playback deterioration at °C.

Also, there is no scattering of pigment.

Furthermore, it has high shelf life and archival properties.

In addition, compared to the case of using other phthalocyanino polymers as mentioned above, the coating properties are good, so the readout S/N ratio is high and there is less variation depending on the location of the S/N ratio. , regeneration deterioration is also reduced.

And, because it contains phthalocyanino dye residues, it is heat resistant,
Light resistance is crystalline.

(2) Specific Examples of the Invention Hereinafter, specific examples of the present invention will be shown and the present invention will be explained in more detail.

Examples The above-mentioned exemplified light-absorbing polymers/161-10 were prepared using Makr
omol=, Chem, 180 2073-2084
Synthesized according to.

That is, the corresponding metal phthalocyanine carboxylic acid was used as an acid chloride, a Friedel-Crafts reaction was performed with the corresponding backbone polymer, phthalocyanine was introduced into the styrene unit, and the predetermined reaction was performed to synthesize it.

Number average molecular weight in polymers and stability
The co-M plateau (comonomer/methyleno) and the phthalocyanide/content (Mo/I-%) are shown in Table IVC.

These structures were identified using infrared and visible absorption spectra and chemical analysis.

Each polymer obtained in this way was
, I) soaked in MSO, etc., and coated on a 30σφQ) glass substrate to a thickness of O,f]μf, and each filtrate
A medium was prepared.

Separately, due to its relative softness, a phthalo 7 anino borimer 11- containing -Pc'-0- as a repeating unit was used to prepare a medium with a 1W value in the same manner. In this case, the PC
' is an unsubstituted iron cap V cyanine residue, and each medium of i+ thus obtained in which Fe has two connecting hands under -L of the ring is concentrated in a 1μ rinsing diameter with a He-Ne laser. A pulse train was irradiated with a light converging unit output xomW).

By changing the pulse width, bits are formed on the surface of the recording layer.
The reciprocal of the 5-bit sensitivity (μs
ec). The results are shown in Table 1 below.

Next, fix the pulse rl+ to lμSec and write %I
l p; komigin,, (/Q, lie -Ne L/-
-Lee rJe, protrusion y.

When condensing the light into 1 μl φ, the condensing part output is 1 mW), 3
0011SeC, (pulse irradiation was performed at a repetition frequency of 100 Hz. Then, this reflected light was detected with a photodiode, and the S/N ratio (dB) of the signal was measured.

The results are shown in Table 1. Note that the noise is lLMs
The value (effective value) was used.

Furthermore, after writing, this readout light was irradiated for 1 minute, and the S/N ratio thereafter was measured to evaluate reproduction deterioration.
Table 1 shows a case where there was a change in the S/N ratio after 1 minute with a mark of ×, and a case where there was no change with a mark of ○.

Separately, after writing, the medium was stored for one week at 400 °C and relative humidity of 80%, and the S/N ratio after storage was measured to evaluate the recording stability. The results are shown in Table 1 with 0 indicating no change at all, △ indicating a slight change, and × indicating significant deterioration.

From the results shown in Table 1, the effects of the present invention are clear.

Note that the medium of the present invention, 16 J-10, is
It has been confirmed that it can be erased and re-entered several times, so stay with it.

Applicant Tokyo Tunkei Kagaku T Gyo Co., Ltd. Agent Patent Attorney Yo Ishii -

Claims (1)

[Scope of Claims] (1) An optical recording medium comprising a recording layer formed of a polymer having side chain pressure of phthalocyanine residues. 2. The optical recording medium according to claim 1, wherein the polymer skeleton is a stereopolymer. 3. Styrene polymer styrene: y unit (1) be/
3. The optical recording medium according to claim 2, wherein a phthalocyanino be/xeno ring is bonded to the c/ring via -CO-.