JPH11105443A - Display forming method to optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly form a highly accurate display by providing an image- receiving layer formed separably on one surface of a base material and an intermedium layer containing a binder and filler between the base material and the image-receiving layer at the time of transferring a display on a heat transfer sheet to the outermost layer of an optical recording medium. SOLUTION: An image-forming layer provided separably on one surface of a base material is formed by a composition containing at least dyeing resin and a releasing agent, and polyvinyl acetal resin is preferably employed for the dyeing resin. Also, an intermediate layer formed between the base material and the image-receiving layer is constituted of a composition containing a binder and a filler, and polyurethane resin or the like is given for the binder, and titanium oxide is given to the filler in inorganic particles, and silicone resin or the like is given thereto in organic particles. A rate of the binder relative to a total quantity of the binder and filler is preferably in a range of 60-80 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a display on an optical recording medium, and more particularly, to a method for forming a display such as characters, figures, symbols, and patterns on the outermost layer of an optical recording medium.

[0002]

2. Description of the Related Art An optical recording medium (optical disk) on which information can be written and / or read by a laser has a larger recording capacity and a random access than conventional recording media. It is used as a recording medium in fields such as computer software, game software, and electronic publishing. In particular, a write-once compact disc ("CD-WO" or "CD-
R "), which has the same reflectance as a read-only compact disc, has the characteristic that it can be reproduced by a read-only compact disc player or drive after recording.

Further, at least one metal reflection layer formed on a surface of a transparent resin substrate along a concave / convex pattern based on the first recording signal and a concave / convex pattern based on the second recording signal. Numerous two-layer optical recording media having a structure in which a formed high-reflectance metal reflective layer is sequentially formed have been proposed (for example, JP-A-8-203125, JP-A-8-249726, and JP-A-8-249726). Nos. 9-50649, 9-54981, and 9-81975). In the above recording medium, the signal recording capacity is physically increased by forming the recording pit surface on the transparent resin substrate into two layers.

In the above-described optical recording medium, for example, when patent information is written, it is desired to print the year of the information on the surface of the optical recording medium. In order to enhance the design of optical recording media, figures,
It is desired to form symbols, patterns, and the like in full color. Such display itself can be easily achieved by, for example, a thermal transfer method using a thermal head or an ink jet method.

However, in the case of the sublimation type thermal transfer system, a high temperature (usually 300 to 300) is required for sublimation of the sublimable dye.
400 ° C.)
There is a problem of damage to the optical recording medium including warpage of the transparent resin substrate. Such a problem is important not only from the viewpoint of the stability of the recording layer but also the stability of the recorded information in the case of an optical recording medium in which the recording layer is composed of an organic dye.

That is, the above-mentioned display is often performed by a user after writing information on the optical recording medium. However, since the above-mentioned recording is originally a heat mode recording by thermal decomposition of a dye, The sublimation-type thermal transfer method in which heat is applied to the recording medium is inappropriate from the viewpoint of the stability of recorded information.

On the other hand, in the case of the ink jet system, there is no problem of damage to the optical recording medium due to heat as described above.
There is a problem such as ink bleeding, and it is difficult to perform high-definition display.

Japanese Patent Application Laid-Open No. 8-203128 proposes an optical disc characterized by including an image portion provided by transferring an image formed on a intermediate transfer medium by a thermal transfer method. In this case, the image forming method (intermediate transfer medium method) is as follows. First, an image is formed by a thermal transfer method on an intermediate transfer medium (heat transfer sheet) having a peelable image receiving layer provided on one surface of a substrate. Then, an image (image receiving layer) on the heat transfer sheet is transferred to an optical recording medium, and the method overcomes the above-mentioned problems in the case of the sublimation type thermal transfer method and the ink jet method.

In the above-described display forming method using an intermediate transfer medium, the following points must be considered in order to form a high-definition display. That is, the image receiving layer does not deviate from the surface of the base material when forming a display on the heat transfer sheet, and the image (image receiving layer) is smoothly peeled off when transferring the display onto the optical recording medium. It is necessary to ensure good transfer.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is a method for forming a display on an optical recording medium using an intermediate transfer medium (sheet to be thermally transferred) so that a high-definition display can be smoothly formed. It is another object of the present invention to provide an improved method for forming a display on an optical recording medium.

[0011]

As a result of various studies, the present inventor has found that the above object can be easily achieved by using a specific intermediate transfer medium (sheet to be thermally transferred). Was.

The present invention has been completed on the basis of the above findings, and the gist of the present invention is that characters and characters are provided on the outermost layer of an optical recording medium.
A method of forming a display of a figure, a symbol, a pattern, or the like,
First, the above-described display is formed on the heat transfer sheet by a thermal transfer method, and then, when the display on the heat transfer sheet is transferred to the outermost layer of the optical recording medium, a peelable image receiving layer is provided on one surface of the base material. A method of forming a display on an optical recording medium, characterized by using a heat transfer sheet provided with an intermediate layer containing at least a binder and a filler between a substrate and an image receiving layer.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present invention, the structure of the optical recording medium is not particularly limited as long as a transparent resin is used for the substrate. Examples of the structure of the optical recording medium include (1) a normal optical recording medium in which at least a recording layer, a metal reflective layer, and a protective layer are sequentially laminated on a transparent resin substrate, and (2) at least one surface of the transparent resin substrate. At least, a low-reflectance metal reflective layer formed along the concave-convex pattern surface based on the first recording signal and a high-reflective metal reflective layer formed along the concave-convex pattern based on the second recording signal Examples include a two-layer type optical recording medium which is sequentially laminated.

As the transparent resin substrate, for example, polycarbonate resin, acrylic resin, polystyrene resin, vinyl chloride resin, epoxy resin, polyester resin, amorphous polyolefin and the like are used. In particular, a polycarbonate resin is preferable because of its high light transmittance and low optical anisotropy.

In the case of a normal optical recording medium, a guide groove, a pit, etc. (groove information, etc.) indicating a recording position are usually formed on the surface of the transparent resin substrate. Groove information and the like are usually given when a substrate is made by injection molding or casting. However, a laser cutting method or a 2P method (Photo-P
(olimer method). In the case of a normal optical recording medium, the thickness of the recording layer is usually 10 to 5000 nm.
The type is not particularly limited as long as it can be recorded by laser light irradiation, and may be either a recording layer made of an inorganic substance or a recording layer made of an organic substance.

In the recording layer made of an inorganic material, for example, Tb-Fe-Co or Dy-F for performing recording by the photothermal magnetic effect is used.
A rare earth transition metal alloy such as e.Co is used. Also,
Chalcogen-based alloys such as Ge.Te and Ge.Sb.Te that change phases may also be used.

In the recording layer made of an organic substance, an organic dye is mainly used. Such organic dyes include macrocyclic azaannulene dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), polymethine dyes (cyanine dyes, merocyanine dyes, squalilium dyes, etc.), anthraquinone dyes, azurenium dyes, and metal-containing dyes. Examples include azo dyes and metal-containing indoaniline dyes. In particular, metal-containing azo dyes are preferable because of their excellent durability and light resistance.

The dye-containing recording layer is usually formed by spin coating,
The film is formed by a coating method such as spray coating, dip coating, and roll coating. In this case, the solvent may be a ketone alcohol solvent such as diacetone alcohol or 3-hydroxy-3-methyl-2-butanone, a cellosolve solvent such as methyl cellosolve or ethyl cellosolve, or a perfluoro solvent such as tetrofluoropropanol or octafluoropentanol. Alkyl alcohol solvents, hydroxyethyl solvents such as methyl lactate and methyl isobutyrate are preferably used.

In the case of a normal optical recording medium, the thickness of the metal reflection layer is usually 50 to 200 nm, and the material is Au,
Ag, Al and the like can be mentioned, but Ag or an alloy thereof is particularly preferable. As an additive element used in the Ag alloy, T
i, Rh, Cu, Ta, Pd, Ni, V, Co, Cr,
Examples include Si, C, B, Sn, P, Zn, Sb, and Mo. These are usually added to Ag at a ratio of 3 atomic% or less. The metal reflection layer is formed by a vapor deposition method, a sputtering method, or an ion plating method. In order to improve the adhesion between the metal reflective layer and the recording layer,
Alternatively, an intermediate layer may be provided for the purpose of increasing the reflectance.

The two-layer type optical recording medium is prepared according to a known method.
For example, after forming an uneven pattern surface based on a first recording signal on one surface of a transparent resin substrate, a low-reflectance metal reflective layer is formed on the uneven pattern surface, and an ultraviolet curable resin is formed on the upper surface of the metal reflective layer. Forming a light-transmissive layer made of a material such as the above, forming an uneven pattern surface based on a second recording signal on the upper surface of the light-transmissive layer, and forming a metal reflective layer having a high reflectivity on the uneven pattern surface; It can be obtained by forming a transparent protective layer made of an ultraviolet curable resin or the like on the upper surface of the reflective layer.

However, a so-called laminating method is recommended in which an irregular pattern surface based on a recording signal and a metal reflective layer are sequentially formed on one surface of a separate transparent resin substrate, and then the two are joined with a transparent adhesive. In this case, the thickness of the metal reflective layer is usually 5 to 1000 nm, and the thickness of the transparent adhesive layer is usually in the range of 2 to 600 nm.

The uneven pattern based on the above recording signal is
Usually, it is provided by a stamper when a transparent resin substrate is produced by injection molding or casting, but may be produced by a laser cutting method or a 2P method (Photo-Polymer method). The dimension of the concavo-convex pattern depends on the wavelength of the laser beam used for reproduction, but is preferably as small as possible.

The material of each of the above-mentioned metal reflective layers can be appropriately selected. However, in the case where a laser beam having a wavelength of 530 nm or less is used for information reproduction to achieve a higher density, a high reflectivity is required. Is preferably formed of Ag or an alloy thereof, and the metal reflective layer (semi-transparent layer) having a low reflectance is preferably formed of Au.

In the case of a normal optical recording medium, recording and reproduction of information are performed by irradiating a laser beam from the transparent resin substrate side to the reflection layer side. Therefore, the outermost layer that forms a display of characters, figures, symbols, patterns, and the like is a protective layer laminated on the metal reflective layer.

On the other hand, in the case of a two-layer type optical recording medium, the recorded information is reproduced by irradiating a laser beam from the low-reflectance metal reflection layer to the high-reflectance metal reflection layer. . Therefore, the outermost layer for forming the display of characters, figures, symbols, patterns, etc., is formed on the non-laser-irradiated surface of the transparent resin substrate (in the case of a two-layer optical recording medium by a bonding method, a metal reflective layer having a high reflectivity). (A transparent resin substrate surface), but it is preferable that the outermost layer be formed by a protective layer separately provided on the surface.

The above protective layer may have two or more layers as necessary. When the number of protective layers is one, the protective layer is the outermost layer. And the above outermost layer (protective layer)
Contains at least an organic filler and / or an inorganic filler, a hydrophilic monomer, and a polymer soluble in the hydrophilic monomer, and the polymer is (meth)
UV curable resin compositions that are homopolymers or copolymers formed from one or more monomers selected from the group of alkyl esters of acrylic acid and N-alkyl substituents of (meth) acrylic amide Preferably, it is formed. By using such a specific composition, the display of characters, figures, symbols, patterns, and the like can be formed with higher definition.

As the organic filler, a water-absorbing and / or oil-absorbing filler is used. For example, acrylic resin, polyacrylate, polymethacrylate, styrene resin, polyester, polycarbonate, modified melamine resin fine particles, polyvinyl alcohol,
In addition to fine particles such as polyacrylamide, polyvinylpyrrolidone, and rubber, crosslinked fine particles of these polymers, as well as lignin, protein, cellulose, and silk powders can be mentioned. In particular, lignin, protein, cellulose, or silk powder is preferable because of high water absorption and oil absorption.

As the above-mentioned inorganic filler, a water-absorbing and / or oil-absorbing filler is used, for example, synthetic silica, talc, clay, calcium carbonate, calcium silicate, barium sulfate, mica, diatomaceous earth silica, aluminum hydroxide, Examples include alumina, zirconium oxide, and zirconium hydroxide.

Examples of the hydrophilic monomer include tetrahydrofurfuryl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, and phenoxyhydroxypropyl (meth). Acrylate, chlorohydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate , Glycerin mono (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol tri ( Data) acrylate, phenyl glycidyl ether (meth) acrylate, dipentaerythritol penta (meth) acrylate, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, acryloyl morpholine, N- vinylpyrrolidone, 2
-Ethoxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, glycidyl (meth) acrylate,
In addition to 1,6-hexanediol acrylate, monomers having a hydroxyl group or an ether group in the molecule, such as di (meth) acrylate of bisphenol A epoxy resin, and the like can be mentioned.

Meanwhile, in the printable optical recording medium described in JP-A-7-169100, homopolymers and copolymers of polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide and the like are used. Such hydrophilic polymers are used. However, in order to appropriately adjust the affinity with the sublimable dye (hydrophobic) described later, it is preferable to use a polymer having a higher hydrophobicity than the above-mentioned polymer.

The above-mentioned highly hydrophobic polymer includes:
Examples include homopolymers or copolymers formed from one or more monomers selected from the group consisting of alkyl esters of (meth) acrylic acid and N-alkyl substituents of (meth) acrylamide. In addition, the N-alkyl substituent of the above-mentioned acrylamide includes a monoalkyl substituent and a dialkyl substituent. Then, specific examples of the above-mentioned polymers include the following polymers (1) to (5).

(1) Homopolymer of alkyl ester of (meth) acrylic acid (2) Copolymer of two or more alkyl esters of (meth) acrylic acid (3) N-alkyl-substituted (meth) acrylamide (4) Copolymer of two or more N-alkyl-substituted (meth) acrylamides (5) Alkyl ester of (meth) acrylic acid and N-alkyl-substituted (meth) acrylamide Copolymer of

The starting monomer for the homopolymer of the above (1) may be a methyl ester of (meth) acrylic acid. From the viewpoint of increasing the hydrophobicity, the (meth) acrylic acid having an alkyl group having 2 or more carbon atoms may be used. ) Acrylic acid alkyl esters are preferred.

As the raw material monomer for the copolymer (2), a combination of two or more alkyl esters of (meth) acrylic acid having a total carbon number of each alkyl group of 4 or more is preferable.

As the starting monomer for the homopolymer of the above (3), an N-alkyl-substituted (meth) acrylamide having a (substituted) alkyl group having 2 or more carbon atoms is preferable. In the case of a dialkyl-substituted product, the number of carbon atoms in the above alkyl group means the total number of carbon atoms in two alkyl groups.

The starting monomer for the copolymer (4) is preferably a combination of two or more N-alkyl-substituted (meth) acrylamides each having a total carbon number of 4 or more in each alkyl group.

As the raw material monomers for the copolymer (5), alkyl esters of (meth) acrylic acid and N-alkyl-substituted (meth) acrylic amides in which the total number of carbon atoms in each alkyl group is 4 or more are used. Is preferred.

The upper limit of the number of carbon atoms is determined by the solubility of the polymer in the hydrophilic monomer.
Therefore, it is appropriately determined in consideration of the molecular weight of the polymer, the type of the hydrophilic monomer, and the amount of use (dissolution) of the polymer.
Among the above polymers, (1) a copolymer of two or more alkyl esters of (meth) acrylic acid, wherein the total number of carbon atoms of each alkyl group is 4 or more; N of the above (meth) acrylamide
Particularly preferred is an alkyl-substituted copolymer in which the total number of carbon atoms in each alkyl group is 4 or more.

Specific examples of the above polymers include methyl methacrylate: propyl methacrylate copolymer, methyl methacrylate: butyl methacrylate copolymer, ethyl methacrylate: propyl methacrylate copolymer, and ethyl methacrylate: butyl methacrylate copolymer. Polymer, N-ethyl methacrylamide: N-butyl methacrylamide copolymer, N, N-dimethyl methacrylamide:
N, N-dipropyl methacrylamide copolymer and the like.

A crosslinking monomer may be added to the UV-curable resin composition in order to improve the crosslinking density (coating film hardness) of the protective layer. Such crosslinkable monomers include trimethylolpropane tri (meth) acrylate, acrylated isocyanurate, 1,4 butanediol di (meth) acrylate, 1,6 hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate. ) Acrylate, dicyclopentadienyl di (meth) acrylate,
Pentaerythritol tetra (meth) acrylate, cyclodecane triacrylate and the like can be mentioned.

Examples of the radical initiator used in the UV-curable resin composition include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-diethoxyacetophenone, An acetophenone-based radical initiator such as 4'-phenoxy-2,2-dichloroacetophenone, a propiophenone-based radical initiator such as 2-hydroxy-2-methylpropiophenone, and an anthraquinone-based radical initiator such as 2-chloroanthraquinone And thioxanthone-based radical initiators such as 2,4-diethylthioxanthone.

In the UV-curable resin composition, the hydrophilic monomer is used in an amount of usually 20 to 85 parts by weight, preferably 30 to 60 parts by weight.
Parts by weight, the polymer is usually 1 to 80 parts by weight, preferably 5 to 40 parts by weight, the crosslinkable monomer is usually 0 to 40 parts by weight, preferably 1 to 20 parts by weight, and the radical initiator is usually 0.1 to 0.1 parts by weight. The filler is used in an amount of usually from 5 to 70 parts by weight, preferably from 20 to 50 parts by weight, based on 100 parts by weight of the UV curable resin. You.

The outermost layer (protective layer) is formed by a method such as a bar coating method, a blade coating method, an air knife coating method, a roll coating method, and a screen printing method.
UV irradiation is performed after the application of the cured resin composition. As the UV lamp, a mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, or the like is used. The irradiation energy amount is usually 150 to 200.
0 mJ / cm ² , preferably 250 to 1000 mJ / c
selected from the range of m ^2.

When there are two or more protective layers, the type of resin of the lower protective layer is not particularly limited, but a UV-curable resin is preferable as in the case of the outermost protective layer. In this case, the lower protective layer is formed by applying a UV curable resin by a method such as spin coating, dip coating, bar coating, or screen printing, and then performing UV irradiation. When there are two or more protective layers, the outermost layer formed of the above-described UV-curable resin composition may be formed only in a region where characters, figures, symbols, patterns, and the like are displayed.

In the present invention, the display of characters, figures, symbols, patterns, etc. is formed on the outermost layer of the optical recording medium as described above. That is, first, the above-described display is formed on the heat transfer sheet by a thermal transfer method, and then the display on the heat transfer sheet is transferred to the outermost layer of the optical recording medium. At that time, in the present invention, a heat transfer sheet is used in which a peelable image receiving layer is provided on one side of a substrate and an intermediate layer containing at least a binder and a filler is provided between the substrate and the image receiving layer. The main point is to do.

By using the specific heat transfer sheet as described above, when forming a display on the heat transfer sheet, the image receiving layer is prevented from being displaced from the surface of the substrate, and the display on the optical recording medium is prevented. When the image is transferred, the image (image receiving layer) is peeled off smoothly and good transfer is performed. As a result, high-definition display can be formed.

First, the heat transfer sheet will be described. Examples of the base material of the heat transfer sheet include unfoamed films such as polypropylene, polyethylene terephthalate, and polycarbonate, foamed films made of polypropylene, polyethylene terephthalate, and the like, synthetic papers, unfoamed films, and laminated sheets of foamed film and cellulose paper. No. In particular, a laminated sheet of a foamed film or a synthetic paper and a cellulose paper has a small occurrence of curl due to heat shrinkage and can form a high-density display when a display is formed on a heat-transferred sheet by a thermal transfer method. Preferred.

The releasable image receiving layer provided on one side of the substrate is composed of a composition containing at least a dyeing resin and a release agent. Examples of the dyeable resin include a polyvinyl acetal resin, a polyester resin, a polycarbonate resin, a cellulose resin, and a vinyl chloride-vinyl acetate copolymer. In particular, polyvinyl acetal-based resin is preferable because the adhesiveness to an intermediate layer described below is appropriate. Examples of the release agent include silicone oil, a fluorine compound, a higher fatty acid, and a wax.
Particularly, silicone oil is preferable. In the image receiving layer, a sensitizer, a curing agent (crosslinking agent), an ultraviolet absorber, a light stabilizer, an antioxidant, a fluorescent brightener, an antistatic agent, a crosslinking accelerator and the like can be appropriately contained.

One example of a particularly preferred image receiving layer is a polyvinyl acetal resin containing a polyvinyl acetal resin, a modified silicone oil and a polyfunctional isocyanate.
0.2 to 1 part by weight of the modified silicone oil
The image receiving layer is composed of a composition containing 0 parts by weight and 1 to 10 parts by weight of a polyfunctional isocyanate.

The intermediate layer provided between the substrate and the image receiving layer is composed of a composition containing a binder and a filler. As the binder, a resin having good adhesion to the image receiving layer is used, and specific examples thereof include a polyurethane resin, a polyacrylate resin, a polyester resin, a polyamide resin, and an ethylene / vinyl acetate resin. In particular, a polyurethane resin is preferable because it can stably disperse the filler and can exhibit appropriate adhesiveness at the interface between the image receiving layer and the intermediate layer.

As the filler, inorganic or organic particles are used. Examples of the inorganic particles include titanium oxide, calcium carbonate, clay and the like, and titanium oxide is particularly preferable. Examples of the organic particles include a silicone resin, an acrylic resin, and a fluororesin, and a silicone resin is particularly preferable. Particles include crushed particles and spherical particles, and spherical particles are preferred.

The ratio of the binder to the total amount of the binder and the filler is preferably in the range of 60 to 80% by weight. When the ratio of the binder is more than 80% by weight, the adhesion between the intermediate layer and the image receiving layer is too low, so that the image receiving layer is not sufficiently prevented from being displaced from the substrate surface when forming a display on the heat transfer sheet. Sometimes. When the proportion of the binder is less than 60% by weight, the adhesion between the intermediate layer and the image receiving layer is too high, so that the image (image receiving layer) may not be peeled off smoothly when transferring the display on the optical recording medium. is there.

The formation of the above-mentioned intermediate layer and the above-mentioned image-receiving layer is carried out by applying a coating solution prepared by dissolving or dispersing the constituents in a suitable solvent, followed by drying. Specifically, the coating solution for the intermediate layer is applied to the surface of the base material and then dried, the coating solution for the image receiving layer is applied to the surface of the formed intermediate layer, and then dried, and if necessary, by heating. Perform aging. The aging is performed to promote the release agent in the image receiving layer to bleed out to the surface and, when a curing agent is used in the intermediate layer or the image receiving layer, to promote a crosslinking reaction thereof.

Examples of the solvent for preparing the coating liquid include alcohol solvents such as methanol, ethanol and isopropanol, aromatic solvents such as benzene, toluene and xylene, and ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. Solvents include ester solvents such as ethyl acetate and butyl acetate, and ether solvents such as tetrahydrofuran and dioxane.
As the coating device, a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, or the like can be used.

The thickness of the intermediate layer is usually from 0.2 to 5 μm, preferably from 0.5 to 3 μm as a dry coating film, and the thickness of the image receiving layer is usually from 0.5 to 0.5 μm as the dry coating film. ~ 2
0 μm, preferably 1 to 10 μm.

Next, a method of forming a display on the outermost layer of the optical recording medium will be described. In the present invention, first, a display is formed on the heat transfer sheet by a thermal transfer method, and then the display on the heat transfer sheet is transferred to the outermost layer of the optical recording medium.

Specifically, first, the ink-coated surface of the color sheet and the image receiving layer of the heat transfer sheet are overlapped, and recording is performed using, for example, a thin-film type line thermal head. The sublimable dye for preparing the ink is not particularly limited,
Various known sublimable dyes, that is, non-azo, anthraquinone, nitro, styryl, naphthoquinone, quinophthalone, azomethine, coumarin, tricyanovinyl, indoaniline, condensed polycyclic, etc. Ionic sublimable dyes can be used.

Next, the image receiving layer on which the display of the heat transfer sheet is formed is superimposed on the outermost layer (UV curable resin composition layer) of the optical recording medium and passed through a laminator. The intermediate layer and the base material are peeled off while leaving the image receiving layer.

As described above, the display is often formed by the user after writing information on the optical recording medium, as described above. However, according to the above-described intermediate transfer medium method, high-temperature heat is not applied to the optical recording medium as in the case of the sublimation-type thermal transfer method, so that recorded information is stably stored.

In the case of a normal optical recording medium, writing (recording) and / or reading (reproduction) of information is performed by a laser beam converged to about 1 μm. That is, recording is performed by melting, evaporation, sublimation, deformation, denaturation, or the like occurring in the laser beam irradiated portion (recording portion) of the recording layer. Reproduction is performed by reading the difference in reflectance between the laser light irradiated part and the non-irradiated part by using the laser light. As the above laser light, a semiconductor laser light is preferably used.

On the other hand, in the case of a two-layer type optical recording medium, the recorded information is reproduced from the low-reflectivity metal reflective layer toward the high-reflective metal reflective layer in the same manner as in the conventional method. This is performed by irradiating light. That is, when reproducing the first recorded signal, the focused laser beam is applied to the metal reflective layer having a low reflectivity, and the reflected light is received. When reproducing the second recording signal, a laser beam focused on the metal reflective layer having high reflectivity is irradiated to receive the reflected light.

[0062]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

Example 1 <Preparation of Optical Recording Medium> Depth: 1600 °, width: 0.45 μm
A solution of a metal-containing azo dye is dropped on an injection-molded polycarbonate resin substrate (5 inches in diameter) having a groove (groove), and is applied by a spin coating method at a rotation speed of 500 rpm, and then dried at 100 ° C. for 30 minutes. A recording layer was formed.

Then, a silver film having a thickness of 800 ° (80 nm) was formed on the recording layer by sputtering to form a reflective layer. Then, a UV curable resin was spin-coated on the entire surface of the reflective layer, and then cured by irradiating UV rays to form a 5 μm protective layer. Then, a UV curable resin composition having a composition shown in the following table was applied to the entire surface of the protective layer so as to have a thickness of 14 μm, and then cured by irradiating ultraviolet rays to obtain an optical recording medium.

[0065]

(1) Methyl methacrylate: butyl methacrylate copolymer (copolymerization ratio = 1: 1): 15 parts by weight (2) Tetrahydrofurfuryl acrylate: 20 parts by weight (3) 1,6-hexanediol di Acrylate: 13 parts by weight (4) Cyclodecane triacrylate: 7 parts by weight (5) 2-hydroxy-2-methyl-1-phenyl-propan-1-one (radical initiator): 5 parts by weight (6) Silk fine Powder: 40 parts by weight

<Preparation of Color Sheet> An ink having the following composition was applied to a 6-μm-thick biaxially stretched polyethylene terephthalate film having a heat-resistant lubricated rear surface and dried to prepare a color sheet. The dry thickness of the colorant layer of the color sheet was about 1 μm.

[0067]

(1) Magenta-based sublimation dye represented by the following structural formula (A): 5 parts by weight (2) AS resin (“Decan AS-S” manufactured by Denki Kagaku Kogyo Co., Ltd.): 10 parts by weight (3) Toluene: 85 parts by weight (4) Cyclohexanone: 10 parts by weight

[0068]

Embedded image

<Preparation of Heat Transfer Sheet>
A coating liquid for an intermediate layer having the following composition was applied to the surface of a synthetic paper made of polypropylene having a thickness of 0 μm with a wire bar, and then dried to form an intermediate layer having a dry thickness of about 2 μm. Next, a coating solution for an image receiving layer having the following composition was applied to the surface of the intermediate layer with a wire bar, and then dried to form an image receiving layer having a dry thickness of about 4 μm. Thereafter, the sheet was subjected to a heat treatment in a 100 ° C. oven for 12 hours to prepare a heat transfer sheet.

[0070]

(Table 3) (Coating solution for intermediate layer) (1) Polyurethane varnish (manufactured by Mitsubishi Chemical Corporation, solid content concentration: 40% by weight): 65 parts by weight (2) Titanium oxide ("Taipek" manufactured by Ishihara Sangyo Co., Ltd.) ): 35 parts by weight (3) Toluene: 5 parts by weight (4) Methyl ethyl ketone: 10 parts by weight (5) Isopropyl alcohol: 5 parts by weight

[0071]

(Table 4) (Coating solution for image receiving layer) (1) Polyvinyl phenyl acetal resin: 70 parts by weight (2) Vinyl chloride-vinyl acetate copolymer resin (“Solvine A” manufactured by Sekisui Chemical Co., Ltd.): 30 parts by weight (3) Modification silicone varnish (“TSR-160” manufactured by Toshiba Silicon Co., Ltd., solid content concentration 60% by weight): 60 parts by weight (4) Amino-modified silicone varnish (“KF-393” manufactured by Shin-Etsu Chemical Co., Ltd.) )): 2.5 parts by weight (5) Polyfunctional isocyanate compound (“Mitec NY-710A” manufactured by Mitsubishi Chemical Corporation, solid content concentration: 75% by weight): 5 parts by weight (6) Toluene: 300 parts by weight ( 7) Methyl ethyl ketone: 300 parts by weight

The polyvinyl phenyl acetal resin in the above table is obtained by acetalizing polyvinyl alcohol (degree of saponification: 99 mol%, degree of polymerization: 1700) with phenylacetaldehyde.

First, a semiconductor laser beam having a center wavelength of 780 nm was irradiated at a recording power of 10.5 mW while rotating the optical recording medium at 5.6 m / s to record an EFM signal.

Next, the ink-coated surface of the color sheet and the image-receiving layer of the heat-receiving sheet are overlapped, and a thin-film type line thermal head having a heating resistor density of 8 dots / mm is used. Recording was performed under the conditions of 8 lines / mm, the applied power of the thermal head: 0.4 W / dot, and the applied pulse width of the thermal head: 5 msec. At that time, there was no problem such as displacement of the image receiving layer of the heat transfer sheet. Then, a high-definition display with a color density of 1.82 was obtained.

Next, the image receiving layer on which the display of the heat transfer sheet is formed is superimposed on the outermost layer (UV curable resin composition layer) of the optical recording medium, and the roll temperature is 150 ° C., and the roll pressing pressure is 2 kg / m ^2. , Feed rate: 70 cm / min. Under the conditions described above. Thereafter, the intermediate layer and the substrate were separated from the optical recording medium while leaving the image-receiving layer of the heat transfer sheet. The peeling operation was performed smoothly, and as a result, the inverted image was successfully transferred to the outermost layer of the optical recording medium.

The recorded portion of the optical recording medium was reproduced by a CD player equipped with a semiconductor laser having the same wavelength as that described above. As a result, a good reproduced signal was obtained. In addition, as a result of measuring the mechanical characteristics (warpage angle) of the optical recording medium, there was almost no change compared to before the image formation, and the result was good.

Example 2 In Example 1, a UV-curable resin composition having the composition shown in Table 2 was used, the coating film thickness was changed to 15 μm, and the following structural formula (B) was used when a color sheet was prepared. Except for using the yellow sublimable dye represented in the same manner as in Example 1, preparation of a color sheet and a heat transfer sheet, recording, and yellow image formation (image formation on a heat transfer sheet and on an optical recording medium) Image transfer) and reproduction. As a result, the image quality, recording / reproducing signal characteristics, and mechanical characteristics were all good.

[0078]

(5) (1) Methyl methacrylate: butyl methacrylate copolymer (copolymerization ratio = 3: 1) (Rohm &: manufactured by Haus “Paraloid 60”): 15 parts by weight (2) Tetrahydrofurfuryl acrylate: 40 Parts by weight (3) 2-hydroxy-2-methyl-1-phenyl-propan-1-one (radical initiator): 5 parts by weight (4) silk fine powder: 40 parts by weight

[0079]

Embedded image

Example 3 In the same manner as in Example 1 except that the UV curable resin composition having the composition shown in Table 3 was used and the coating film thickness was changed to 15 μm, the color sheet and the thermal transfer were performed in the same manner as in Example 1. Preparation, recording, red image formation, and reproduction of a sheet were performed. As a result, the image quality, recording / reproducing signal characteristics, and mechanical characteristics were all good.

[0081]

(6) (1) Ethyl methacrylate: butyl methacrylate copolymer (copolymerization ratio = 1: 1) (Rohm &: manufactured by Haus Co., Ltd., “Paraloid 66”): 15 parts by weight (2) Tetrahydrofurfuryl acrylate: 20 Parts by weight (3) 1,6-hexanediol diacrylate: 15 parts by weight (4) cyclodecane triacrylate: 7 parts by weight (5) 2-hydroxy-2-methyl-1-phenyl-propan-1-one (radical (Initiator): 5 parts by weight (6) Silk fine powder: 38 parts by weight

Example 4 In the same manner as in Example 1 except that the UV-curable resin composition having the composition shown in Table 4 was used and the coating film thickness was changed to 15 μm, the color sheet and the thermal transfer were performed in the same manner as in Example 1. Preparation, recording, red image formation, and reproduction of a sheet were performed. As a result, the image quality, recording / reproducing signal characteristics, and mechanical characteristics were all good.

[0083]

(1) N-ethyl methacrylamide: N-butyl methacrylamide copolymer (copolymerization ratio = 1: 1): 15 parts by weight (2) tetrahydrofurfuryl acrylate: 40 parts by weight (3) 2-hydroxy -2-methyl-1-phenyl-propan-1-one (radical initiator): 5 parts by weight (4) fine silk powder: 40 parts by weight

Example 5 In the same manner as in Example 1 except that the UV curable resin composition having the composition shown in Table 5 was used and the coating film thickness was changed to 15 μm, the color sheet and the thermal transfer were performed in the same manner as in Example 1. Preparation, recording, red image formation, and reproduction of a sheet were performed. As a result, the image quality, recording / reproducing signal characteristics, and mechanical characteristics were all good.

[0085]

(1) N, N-dimethylmethacrylamide: N, N-dipropylmethacrylamide amide copolymer (copolymerization ratio = 1: 1): 15 parts by weight (2) Tetrahydrofurfuryl acrylate: 20 parts by weight (3) 1,6-hexanediol diacrylate: 15 parts by weight (4) cyclodecane triacrylate: 7 parts by weight (5) 2-hydroxy-2-methyl-1-phenyl-propan-1-one (radical initiator ): 4 parts by weight (6) Silk fine powder: 39 parts by weight

Example 6 First, an irregular pattern surface based on a first recording signal was formed on one surface of a polycarbonate resin substrate (diameter: 5 inches) by a stamper method, and an Ag film having a thickness of 800 ° (80 nm) was formed on the surface by a sputtering method. A first layer was formed by forming a reflective layer. Similarly, a concavo-convex pattern surface based on the second recording signal is formed on one surface of a polycarbonate substrate by a stamper method, and an Au reflection layer having a thickness of 800 ° (80 nm) is formed on the surface by a sputtering method to form a second element. . Next, after applying an ultraviolet curable resin in a thickness of 40 μm to the surface of the Ag reflection layer of the first element by a spin coating method, the Au reflection layer of the second element is superimposed on the applied surface, and ultraviolet rays are applied. Irradiated and cured, the two were joined.

Then, a UV curable resin composition having the same composition as that used in Example 1 was applied to the entire surface of the polycarbonate resin substrate of the first element in a film thickness of 14 μm, and then cured by irradiating ultraviolet rays. Thereafter, the same operation as in Example 1 was performed to obtain an optical recording medium in which a red image was formed on the outermost layer (UV curable resin composition layer). Both the image quality and the mechanical characteristics (warpage angle) were good.

The above-mentioned two-layer type optical recording medium has a center wavelength of 515.
A blue-green semiconductor laser beam having a wavelength of 20 mW and a beam spot diameter of 0.48 μm is irradiated from the Au reflection layer side,
As a result of reproducing the first recording signal and the second recording signal, both of them were successfully reproduced. In addition, 5
The reflectivity of the Ag reflection layer at 15 nm is 75%,
The reflectivity of the Au reflection layer was 25%.

Also, as a result of irradiating the above-mentioned two-layer type optical recording medium with a semiconductor laser beam having a center wavelength of 430 nm from the side of the Au reflection layer and reproducing the first recording signal and the second recording signal, both of them were obtained. , And could be reproduced well. The laser body used was composed of a solid-state laser excited by a semiconductor laser manufactured by HMG Photonics: LiSrAlF6 crystal doped with Cr (fundamental oscillation wavelength 860 nm), and its wavelength was 430 (n), which was a harmonic of the solid-state laser.
m). The reflectivity of the Ag reflective layer at 430 nm was 65%, and the reflectivity of the Au reflective layer was 20%.
%Met.

Comparative Example 1 A color sheet and a heat transfer sheet were prepared in the same manner as in Example 1 except that the intermediate layer was omitted and the heat transfer sheet without the intermediate layer was used when the heat transfer sheet was prepared. Creation, recording, red image formation, and reproduction were attempted. As a result, when the image was transferred onto the optical recording medium, the transfer operation was not smoothly performed, and the transfer target paper was torn.

Comparative Example 2 The procedure of Example 1 was repeated, except that the use of titanium oxide in the intermediate layer was stopped during the preparation of the heat transfer sheet, and that the heat transfer sheet having an intermediate layer containing no filler was used. , Recording, red image formation and reproduction of a color sheet and a heat transfer sheet were attempted. As a result, when an image was formed on the heat transfer sheet, a shift occurred between the base material of the heat transfer sheet and the image receiving layer, and a high-definition display could not be obtained.

Comparative Example 3 In Example 1, a display forming method by a heating / contact method using a thermal head using a commercially available sublimation type thermal transfer printer was used instead of the display forming method used in Example 1. In the same manner as in Example 1, recording, red image formation, and reproduction were performed. As a result, the image quality was good, but due to the thermal damage, the recording / reproducing signal characteristics were remarkably inferior, and the mechanical characteristics (warpage angle) deteriorated.

Comparative Example 4 In Example 1, a display forming method by a heating / contact method using a thermal head using a commercially available fusion-type thermal transfer printer was employed instead of the display forming method used in Example 1. In the same manner as in Example 1, recording, red image formation, and reproduction were performed. As a result, the image quality was reduced in Example 1
The recording / reproducing signal characteristics and the mechanical characteristics were deteriorated.

Comparative Example 5 Recording, red image formation and reproduction were performed in the same manner as in Example 1 except that a commercially available ink jet printer was used instead of the display forming method used in Example 1. Was. As a result, the recording / reproducing signal characteristics and the mechanical characteristics were good, but the image quality was poor. In particular, the image quality under high humidity was extremely poor.

Table 9 below summarizes the results of the above Examples and Comparative Examples. The meanings of the symbols in Table 9 are as follows. ◎: remarkably good, ○: good, Δ: poor, ×: remarkably poor

[0096]

[Table 9]

[0097]

According to the present invention described above, there is provided a method for forming a display on an optical recording medium using an intermediate transfer medium (heat transfer sheet) so that a high-definition display can be smoothly formed. An improved method for forming a display on an optical recording medium is provided.

Claims (6)

[Claims] 1. A method for forming a display such as a character, a figure, a symbol, and a pattern on an outermost layer of an optical recording medium, wherein the display is first formed on a heat transfer sheet by a thermal transfer method. When transferring the display on the heat transfer sheet to the outermost layer of the optical recording medium, an intermediate layer containing a peelable image receiving layer on one side of the base material and containing at least a binder and a filler between the base material and the image receiving layer A method for forming a display on an optical recording medium, comprising using a heat transfer sheet provided with a layer. 2. The method according to claim 1, wherein the transparent resin substrate of the optical recording medium is a polycarbonate resin. 3. The method according to claim 1, wherein the optical recording medium is an optical recording medium in which at least a recording layer, a metal reflective layer and a protective layer are sequentially laminated on a transparent resin substrate. 4. The method according to claim 3, wherein the recording layer of the optical recording medium comprises an organic dye. 5. An optical recording medium comprising at least one surface of a transparent resin substrate, a metal reflective layer having a low reflectivity formed at least along an uneven pattern surface based on a first recording signal, and a second recording signal. 3. The method according to claim 1, wherein the optical recording medium is formed by sequentially laminating a metal reflective layer having a high reflectivity formed along a concave / convex pattern based on the optical recording medium. 6. The method according to claim 1, wherein the outermost layer of the optical recording medium comprises the following UV-curable resin composition. UV curable resin composition: at least an organic filler and / or
Or an inorganic filler, a hydrophilic monomer, and a polymer soluble in the hydrophilic monomer, wherein the polymer is an alkyl ester of (meth) acrylic acid and an N-alkyl-substituted (meth) acrylamide. A UV-curable resin composition which is a homopolymer or a copolymer formed from one or more monomers selected from the group consisting of: