JPH02160582A - New optical recording material - Google Patents

Abstract

PURPOSE:To increase preservable stability at high temperature and humidity and ensure adequate use even under severe use conditions such as bending by providing a metal glossy layer and a metal supply layer formed by heating a specific composition and as metals with specific melting point, coefficient of heat transfer and specific particle diameter. CONSTITUTION:The subject material consists of a metal glossy layer and a metal supply layer formed by heating an optical recording material composition containing an organic metal salt oxidizer and a reducing agent and also a hydrophobic organic polymer compound as a binder. The metal used is one at a melting point of 200 deg.C or more and 1,800 deg.C or less and with a coefficient of heat transfer of 1W.m<-1>.K<-1> or more and 450W.m<-1>.K<-1> or less at 0 deg.C. The diameter of metal particles in the metal glossy layer is 5nm or more and 100nm or less, and the combined film thickness of the metal glossy layer and the metal supply layer is 1mum or more and 50mum or less. That is, the metal glossy layer is formed on the surface by adding an organic metal salt oxidizer to an organic polymer compound and controlling the particle diameter, shape and reduction rate of metals to be reduced during heating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides a novel digital recording material suitable for writing and reading mainly with laser light.

[Conventional technology]

BACKGROUND ART In recent years, laser-related technology has made remarkable progress, information has been digitized, and various new optical recording materials necessary for this have been proposed.

A typical digital recording material is an optical disc. Separately, high-density optical card materials have been proposed that can be easily handled and carried around at all times. As an example of this, JP-A-59-5021
The optical card developed by Drexler, which is described in Japanese Patent Application Laid-Open No. 58-188346 and others, is famous. Furthermore, optical card materials are being developed by various companies using materials similar to those used for optical disks.

On the other hand, optical tape has been proposed as a material that is more compact than optical disks and can record a large amount of information.

Although several systems and materials have been proposed, there are problems with writing sensitivity, storage stability of recording materials, recording density,
The characteristics necessary for recording materials, such as error rate, are still insufficient.

For example, Drexler has proposed that a reflective film be formed on the surface of a wet silver salt photographic material through special treatment, and used in optical cards. Because it uses gelatin, it has been pointed out that it cannot be stored for long periods at high temperatures and high humidity. Furthermore, since optical tapes and optical cards are expected to be used under harsher conditions than optical disks, such as bending, existing metal thin film materials may crack, so new materials are being sought after. Ta.

[Problem to be solved by the invention]

The present invention provides an optical recording material that has excellent storage stability under high temperature and high humidity conditions and can be satisfactorily used as an optical recording material even under severe usage conditions such as bending.

Furthermore, the present invention attempts to provide a low-cost recording material that can be continuously produced. That is, very common industrial production means such as continuous coating with a roll coater and continuous heating with a hot roll can be selected, thereby making it possible to reduce the cost of the recording material.

[Means to solve the problem]

The present invention relates to a completely new optical recording material that utilizes the fact that an organometallic salt oxidizing agent and a reducing agent in a hydrophobic organic polymer compound undergo a redox reaction by applying heat. That is, the key point of the present invention is that the particle size, grain shape, and reduction rate of the metal reduced by heating are controlled to form a metallic luster layer on the surface layer of this recording material.

The metallic luster layer and the metal supply layer in this optical recording sensitive material may be formed by providing two separate layers, or by providing two layers at the same time.

As the second layer, a composition in which an organometallic salt oxidizing agent and a reducing agent are dispersed or dissolved in a hydrophobic organic polymer compound is applied.
The usual method is to dry it.

Furthermore, the second layer may be coated with a metal catalyst core or a composition containing a metal catalyst core, or
By treating the surface layer of the -th layer, metal catalyst nuclei may be formed in the surface layer.

The layer structure of the optical recording material produced in this way may be such that the metallic luster layer and the metal supply layer are two layers with a clear boundary, or even if there is no such layer, it is not important for the optical material. Alternatively, the boundary between the two layers may not be distinguishable at all and may be regarded as one layer.

That is, by containing an organometallic salt oxidizing agent and a suitable reducing agent in an organic polymer compound, the organometallic oxidizing agent is reduced mainly to the metal catalyst nuclei in the surface layer during heating.
It has a metallic luster layer. The discovery that it is possible to form a metal thin film layer with high reflectance in this way is due to
This is completely new.

The optical material of the present invention can be defined as follows. That is: At least a metallic luster layer and a metal supply layer are formed by heating an optical recording material composition containing at least an organometallic salt oxidizing agent and a reducing agent, and whose binder is a hydrophobic organic polymer compound. In optical recording materials with
(a) The metal has a melting point of 200°C or higher and 1800°C.
and (ff) thermal conductivity is 1- at 0°C.
・It is a metal of "1.K-1 or more and 450-.s-1 or less, and (c) the metal particle size in the metallic luster layer is 5n
An object of the present invention is to provide an optical recording material having a film thickness of 1 μm or more and 1100 nm or less, and (d) a combined thickness of the metallic luster layer and metal supply layer of 1 μm or more and 50 μm or less.

The metallic luster layer is a layer that has luster due to fine metal particles, and the metal supply layer is a layer that supplies metal to the metallic luster layer by heating.

An important point in the present invention is that there is only one layer containing metal particles, regardless of the form.

These metal species have melting points of 200℃ or higher and 1800℃ or higher.
℃ or less, and has a thermal conductivity of 1 - 1 - 1 or more and 450 - 2 -1 1 [-1 or less at 0 ℃. Specifically, silver, gold, copper, tellurium, bismuth,
Examples include palladium, cobalt, nickel, lead, chromium, and titanium. Very preferably the metal species is silver. Metals with a melting point of 200° C. or lower tend to have poor stability of the metallic luster layer, while those with a melting point of 1800° C. or higher result in extremely poor sensitivity when recording with a laser or the like.

In addition, if the thermal conductivity is less than -1 in 1-11 at 0°C, the shape of the recording pit will be distorted when recording with a laser, etc., resulting in a high error rate, making it difficult to put it into practical use. If the value is less than 1 in 450-1, the sensitivity becomes very poor.

The metal particle size in the metallic luster layer is 5 nm or more and 100 nm or less, and there is no obvious reason why a metallic luster layer is currently formed, but as a result of electron microscopy observation, particles with particle diameters outside this range are not formed. Moreover, the particle size distribution of these metal particles is very uniform, with more than 90% of the metal particles having a size of 15 nm or more and 40 nm or less. Since the metal particle diameters are uniform in this way, it is a good optical recording material with uniform sensitivity on the micron order and a low error rate. Furthermore, according to observation using an electron microscope, the distance between metal particles existing within a thickness of 0.2μ steel in the depth direction of the metallic luster layer from the surface of the metallic luster layer is such that most of the metal particles are not in contact with each other. The average interval is 30 or more1
Optical recording materials that have a very closely packed morphology in which the average spacing between metal particles is less than 31 nm, with very few metal particles being separated by more than 25 nm, tend to have poor sensitivity.

In addition, the combined film thickness of the metallic luster layer and the metal supply layer is 1 μm.
If it is below, the reflectance of the metallic luster layer will be insufficient due to insufficient metal supply, resulting in a high error rate. Also,
If it is 50 μm or more, it is not preferred in terms of cost in practical terms, and more preferably it is not less than ltI and not more than 25 μm.

As the organic silver salt oxidizing agent, long-chain fatty acids, metal salts of various carboxylic acids, metal salts of saccharic acid and benzotriazole, etc. can be used. Among the various metals, the most preferred are It is silver and contains long chain fatty acids, and silver salts of various carboxylic acids, silver saccharinate and silver salts of benzotriazole can be used.
Among these, silver behenate, silver stearate, and the like are particularly useful.

The reducing agent for the organic metal salt oxidizing agent may be any substance as long as it can reduce the organic metal salt oxidizing agent.In particular, as the reducing agent for the organic metal salt oxidizing agent, ordinary thermal development Selected from hindered phenols that have a sterically bulky group attached to the carbon adjacent to the carbon to which the phenolic hydroxyl group is attached, sterically inhibiting the hydroxyl group used in type dry silver salt sensitive materials. can.

For example, 2,6-di-t, butyl-4-methylphenol, 2,2'-methylenebis-(4-methyl-5-t-
butylphenol), 2,2'-methylenebis-(4
-ethyl-6t-)-1-ruphenol), 2,4.
4-ToIJ methylpentylbis-(2-hydroxy-
3,5-dimethylphenyl)methane, 2,5-di[-
Butyl-4-methoxyphenol and the like can be mentioned. In addition, reducing agents for silver salts such as hydroquinone, 2.5-dimethylhydroquinone, chlorohydroquinone, p-aminophenol, methylhydronaphthalene, phenidone, methyl gallate, P-phenyldenol, bisphenol A, 2.4- Dihydroxybenzoic acid, p-methoxyphenol can also be used. The amount of reducing agent varies depending on the type of reducing agent, etc., but for boat fishing, approximately 0.01 mmole per 1 mole of organic silver salt oxidizing agent is used.
0 mole, preferably about 0.1 mole to about 3 mole.

The organic silver salt oxidizing agent and reducing agent are mixed and dispersed in a solvent and a hydrophobic polymer compound in advance to prepare a uniform coating solution. Here, the selection of a hydrophobic organic polymer compound as a binder is not only important for creating a stable coating solution, but also for the storage stability of the optical recording material obtained after coating, drying and heat development. This is extremely important as it has a large impact. Especially in optical recording materials for applications that require storage conditions of high temperature and high humidity, bland and sweet binders such as gelatin and polyvinyl alcohol should be avoided.

In the present invention, a more preferable binder is appropriately selected from a wide range of hydrophobic organic polymer compounds such as polymethyl methacrylate, polyvinyl formal, polyvinyl butyral, vinyl chloride vinyl acetate copolymer, cellulose acetate, and polystyrene. Can be done. This hydrophobic binder is selected in various ways depending on the organometallic salt oxidizing agent and metal species, so it cannot be generalized, but for example, in the case of an organic silver salt oxidizing agent, the weight ratio is about 10:1 to 1. There are approximately 1 to 10.

Moreover, a hydrophobic organic solvent is used as a more preferable solvent. A hydrophobic organic solvent is an organic solvent containing at least one organic solvent in which the solubility of water in the solvent is 25% by weight or less at 20°C. Examples of organic solvents in which the solubility of water in the solvent is 25% by weight or less at 20°C include methyl ethyl ketone, methyl propyl ketone, cyclohexane, methyl subtyl ketone, isopropyl ether, ethyl-nm7” ethyl ether, ethyl formate, ethyl acetate, and acetic acid. Methyl, nm butyl alcohol, isobutyl alcohol, toluene, hexane, ethylbenzene, chloroform, etc. can be mentioned. Therefore, the term "hydrophobic organic solvent" as used in the present application refers to a solvent containing a small amount (or at least one) of the above-mentioned organic solvent. It is an organic solvent, for example, a mixture of toluene, methyl ethyl ketone, and ethanol may be used.

The reflective metallic luster layer of the present invention is manufactured as follows. That is, minute catalyst nuclei are formed on a layer (optical recording material composition layer) containing an organometallic salt oxidizing agent, reducing agent, etc. that has been coated in advance, and further under suitable heating conditions, for example, at a temperature of at least 70°C. When heated for several seconds to several minutes, a recording material layer with metallic luster is formed on the surface layer. As a catalyst,
Naturally, it depends on the type of metal used, and it is possible to think of a metal catalyst suitable for that type of metal, but it is easy to use the metal itself or a metal type that is more responsible than the metal used in the surface layer. These metal nuclei, which may be formed, do not need to be a single metal species, but may be a composite system, a sulfide, or the like.

In addition, as a catalyst nucleation method, a method of dispersing these minute catalyst nuclei in a solvent containing an appropriate binder and coating it on the surface, or a method of depositing a minute amount of catalyst nuclei on the surface under vapor phase conditions such as vapor deposition. It is also possible to take a method of forming the pores.

In addition, by covering the surface of the organometallic salt oxide layer with a strong reducing agent or by exposing the surface to a reducing gas such as hydrogen gas for a short period of time, a catalyst nucleus consisting of the metal species itself can be formed on the surface. For example, as a typical example, a method for manufacturing a silver metallic luster layer is an electroless method in which palladium metal nuclei are applied to the surface layer by sequentially immersing it in an aqueous solution of stannous chloride and an aqueous solution of palladium chloride. Methods include applying metal nuclei by plating, vacuum-depositing metals such as platinum, gold, silver, and palladium onto the surface, and dispersing these minute catalyst nuclei in a solvent containing an appropriate binder and coating it on the surface. Alternatively, a stronger reducing agent such as ascorbic acid may be used to cover the surface of the organic silver salt oxidizing agent layer. Furthermore, a compound that forms silver sulfide nuclei such as sulfide-soda may be placed on the surface layer, or silver metal development nuclei may be formed on the surface by exposing the surface to a reducing gas such as hydrogen gas for a short time. It may be provided.

Suitable heating conditions for this optical recording material are at least 70
Heating is performed for several seconds to several minutes at a temperature of 0.degree. C. or higher, preferably for about 2 to 100 seconds at 90 to 160.degree.

Further, this metallic silver luster layer incorporates an extremely small amount of metal development nuclei more harmful than silver, and silver or a metal species more harmful than silver is essential for the development of this lustrous layer. Examples of metals more responsible than vA include palladium, platinum, gold, rhodium, ruthenium, thallium, and mercury. As described above, these metal cores may be a single metal species, or may be a composite thread, a sulfide, or the like.

The optical recording material of the present invention can contain various additive components to enhance the intended performance of the material. For example, compounds can be introduced to control the size of metal grains in the metallic luster layer. . In the case of silver, for example, toning agents such as phthalazinone used in dry silver salt sensitive materials can be cited. Furthermore, if necessary, antifogging agents, aggravating agents, silver halide or silver halide forming components, etc. can be added.

Furthermore, among the side reaction products formed by the reaction between the organic silver salt oxidizing agent and the reducing agent, organic compounds such as fatty acids formed from silver salts of long-chain fatty acids are present in the binder and play a role as a plasticizer. You can control the writing sensitivity.

The optical recording material of the present invention is provided with a transparent protective layer for the purpose of protecting the recording layer. This protective layer is selected from highly transparent organic polymer compounds such as polycarbonate, polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, and polyethylene terephthalate.

Furthermore, even if the back side of the optical recording material layer is composed only of a base film on which the optical recording layer is applied,
A reinforcing layer against bending etc. may be present on the back surface. Additionally, the surface of the transparent protective layer is usually treated to prevent scratches and the like.

The optical recording material of the present invention is generally card-shaped, but may be disc-shaped or tape-shaped.

The optical recording material of the present invention can be recorded with various laser light sources having appropriate power, typical examples of which are He-Ne laser and semiconductor laser.
For example, using a semiconductor laser of about 10+wW, 2
With a beam diameter of ~3μ, writing can be performed at a speed of several tens of cm 1' sec.

The optical recording material of the present invention can be used as a so-called write-once type recording material, and the user can write on it as needed.Once written, it cannot be erased, so it can be used in applications where evidence is required. can also be used. Also, if you write information in advance and read-only RO? It can also be used as an l card.

EXAMPLES Next, the present invention will be described in detail with reference to Examples, but these Examples are not intended to limit the scope of the present invention in any way.

Example 1 Phenyldiazosulfonic acid salts of Cr"", Go" and Cu" were prepared by reacting phenyldiazosulfonic acid with metals (Cr, Co and Cu).

A suspension consisting of the following components was prepared using each phenyldiazosulfonate.

Each phenyldi7zosulphosphate
14g polyisobutylene
7g methylcyclohexane
62g1-phenyl-3-pyrazolidone
16g i.e.
These suspensions were homogenized using a ball mill for about 15 hours for all of the above three components, and then passed through a filter with an average pore size of 1.5 μm to remove undispersed matter.

After drying these suspensions with a small applicator, the slint was selected to be 9.5 μm and 100
It was applied uniformly onto a polyester film with a thickness of μm and dried under conditions of a temperature of 22° C. and a humidity of 50% R)I.

Thereafter, silver was deposited on the surface of each dry composition and heated at 135° C. for 10 seconds using a heater block. Then, a metallic luster layer was formed on each surface layer.

The reflectance (wavelength 830 ns) is 38% when phenyldiazosulfonate with Cr"°9 is used, and the reflectance is 38% when CO'4
In the case of phenyldiazosulfonate, it is 43χ, and C
In the case of phenyldiazosulfonate of u'', it was 39%.

Further, the cross sections of these three types of optical recording materials were observed using a transmission electron microscope. The particle size of the metal particles in the metallic luster layer is 5 nm or more and 40 nm or less, and 15 of the metal particles are
Metal particles with a particle size smaller than nm have a total Cr”-
5.8 when phenyldiazosulfonate is used.
%, in the case of the phenyldiazosulfonate of Co" was 6.2%, and in the case of the phenyldiazosulfonate of Cu L" it was 6.5%.

Furthermore, the average distance between metal particles in the surface layer of the metallic luster layer is 3
For each type of optical recording material, the average spacing was calculated by measuring 100 average spacings, and the value was within 50-Qnw. Further, no metal particles having a particle size of 5 nm or more were present in layers other than the metallic luster layer.

Example 2 Instead of the 1W fluorinated 3-pyrazolidone used in Example 1, an appropriate amount of hydroquinone was added to prepare three types of suspensions. All three suspensions were homogenized using a ball mill for about 15 hours, and then passed through a filter with an average pore size of 1.5 μm to remove undispersed matter.

After drying these suspensions with a small applicator, select a slit to be 9.5μ■, and apply 100μμ
It was applied uniformly onto a polyester film having a thickness of m and dried under conditions of a temperature of 22° C. and a humidity of 50% RH. and,
Silver was deposited on the surface of each glossy recording material composition in the same manner as in Example 1. This film was then heated at 135° C. for 10 seconds. Then, a metallic luster layer was formed on the surface layer.

In addition, the cross sections of these glossy recording materials were observed using a transmission electron microscope. Then, the particle size of the metal particles in the metallic luster layer was greater than or equal to fanm and less than or equal to 74 nm.

Furthermore, among the metal particles, metal particles with a particle size larger than 40 nm account for 8.6% of the total C,144 phenyldiazosulfonate, and (, *e phenyldiazosulfonate). In the case of the sulfonate, it was 7.4%, and in the case of the Cu'' phenyldiazosulfonate, it was 5.2%.

Furthermore, the average distance between metal particles in the surface layer of the metallic luster layer is 3
For each type of optical recording material, the distance between 100 particles was measured and the average distance was calculated, and the value was within 5nIl to 7nm.

Further, as a result of a writing experiment using a semiconductor laser (830 nm) of 20 mW, it was possible to record on each optical recording material with the laser.

Example 3 P consisting of the following ingredients! A suspension was created.

Behen FIIim 20g polyvinyl butylar road
18g8g Phthalazine
4g2.2-methylenebis(4-
ethyl-6-t-butylphenol)
9g 2-butanone 240g
60 g of toluene This suspension was homogenized by a ball mill for about 12 hours, and then passed through a filter with an average pore size of 1.5 μm to remove undispersed matter.

This suspension is applied after drying with a small applicator.
Select a slit so that it is μ ■, apply it uniformly on a 100 μm thick polyester film, and apply it at a temperature of 22°C.
, and dried under a red safety light at a humidity of 30% RH. (
The obtained sample is designated as sample No. 1. ) Sample No. 1 was then sequentially immersed in the following aqueous solutions for 10 seconds each, then washed with water and air-dried. (Sample No.
, 2) (Aqueous solution 1) Stannous chloride 7g distilled water
200 m concentrated hydrochloric acid
4a! (Aqueous solution 2) Palladium chloride 0.1 g Distilled water 200 adm Concentrated hydrochloric acid 5 m Each of the obtained samples was heated at 130° C. for 10 seconds.

Sample No. 1 turned black, whereas sample No.

No. 2 had a glossy layer with silver precipitated on the surface layer.

A cross section of the optical recording material of Sample No. 2 was observed using a transmission electron microscope. Then, the particle size of the silver particles in the metallic luster layer was 15 nm or more and 35 nm or less. Further, the average spacing between metal particles in the surface layer of the metallic luster layer was calculated by measuring the spacing between 100 particles, and the average spacing was 6 nm.

Example 4 A suspension consisting of the following components was prepared.

Silver behenate 20g polyvinyl butyral
18g8g Phthalazine
4 g 2-tert-butyl-6-(3-t-butyl-2-hyphenyl) 4-methylphenyl 7-acrylate 8 g Methyl ethyl ketone 185 g Toluene 55 g Sodium bromide 0.3 g This suspension contains approx.
After homogenization by ball milling for an hour, the average pore size is 1.5
Undispersed substances were removed through a μm filter.

Thereafter, it was applied and dried under the same conditions as in Example 3. However, the coating was applied so that the film thickness after drying was 11 μm, and the coating was dried under a red safety light. This sensitive material was immersed in an aqueous tin chloride solution and an aqueous palladium chloride solution in the same manner as in Example 3, so that palladium was adsorbed onto the surface of the sensitive material. Then, when heated with a block heater at 150°C for 10 seconds, silver precipitates on the surface.
A metallic luster layer was formed.

According to transmission electron microscopy, the particle size of the silver particles in the metallic luster layer was 15 nm or more and 50 nm or less. Also, 4
Silver particles having a particle size larger than Onm accounted for 3% or less of the total.

Moreover, the average number of metal particles in the surface layer of the metallic luster layer is 10
The average spacing was calculated by measuring the spacing between zero particles, and the value was 7 nm.

FIG. 1 shows a transmission electron micrograph.

In FIG. 1, A is an adhesive layer, B is a metallic luster layer, and C is a metal supply layer.

The method for preparing a sample for an electron microscope is as follows;
6/4) and an ultramicrotome (LKB-V).
) Ultrathin sections were prepared. After attaching the collodion support film, the section was placed on a mesh and subjected to carbon evaporation treatment to prepare a sample for microscopy.

Electron microscope: Hitachi H~500 Accelerating voltage: 75kV Observation method 2 Transmission electron microscopy (TIliM)
Example 5 A suspension consisting of the following components was prepared.

4 behenic acids 20g polyvinyl butyral
18g8g Phthalazine
4g2-t-Butyl-6-(3-t-butyl-2-7Foxy5-methylbesidyl)-4-methylphenyl 7-acrylate
8g methyl ethyl ketone
185g toluene
55゜Sodium Bromide 0.3
g1.1.1', l'-tetrabromo-〇-xylene:/
0.2゜This suspension had an average pore size of 1 after being homogenized by a ball mill for about 12 hours.
．． Undispersed matter was removed through a 5μ filter.

This suspension was coated using a small blade coater.

This was dried at 50°C for 10 minutes, and then 22°C, 550% R
It was stored under H conditions. The coating and drying was performed under safe light. Thereafter, in the same manner as in Example 3, physical development nuclei (palladium) were adsorbed onto the surface.

Then, it was heated at 140° C. for 110 seconds using a roll heater. Laser recording was performed on this sample using a 1(e-Ne laser beam (beam diameter 3μ, emission output 3IIM) having an emission wavelength of 633n+*.A pit of 3μ stiffness was formed in the n source. According to transmission electron microscopy, the particle size of the silver particles in the metallic luster layer was 100,000 yen.
It was 38 nm or less.

Further, silver particles having a particle size larger than 15 nm accounted for 6% or less of the total. Further, the average spacing between metal particles in the surface layer of the metallic luster layer was calculated by measuring the spacing between 100 particles, and the average spacing was 5 nm.

The results of Examples 1-5 show that the present invention is effective.

(Effects of the Invention) According to the present invention, a flexible and stable digital recording material that can be laser recorded can be provided.

[Brief explanation of the drawing]

FIG. 1 shows a transmission electron micrograph of the recording material obtained according to Example 4. A: Adhesive layer B: Metallic luster layer C: Metal supply layer (and 1 other person) Procedure dispute correction 11 (Method) % formula % Case indication Patent application No. 63-313681, Title of invention: New optical recording material/Amendment Relationship with the case of a person who does the following Patent applicant (003) Asahi Kasei Corporation

Claims (3)

[Claims] (1) Contains at least an organometallic salt oxidizing agent and a reducing agent,
In an optical recording material having at least a metallic luster layer and a metal supply layer, which is formed by heating an optical recording material composition in which the binder is a hydrophobic organic polymer compound, the metal has a melting point of 200° C. or higher. 1800℃
The thermal conductivity is 1W・m^- at 0℃.
^1・K^-^1 or more 450W・m^-^1・K^-^
1 or less, and the combined thickness of the metallic luster layer and the metal supply layer is 1 μm or more and 50 μm or less. (2) The metal particle size in the metallic luster layer is 5 nm or more and 100 nm
m or less, and 90% or more of the metal particles are 15n
The optical recording material according to claim 1, which has a particle size of m or more and 40 nm or less. (3) 0 in the depth direction of the metallic glossy layer from the surface of the metallic glossy layer.
．． The optical recording material according to claim 2, wherein the average distance between metal particles within 2 μm is 3 nm or more and 15 nm or less.