JPH10188344A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical recording medium which deals with an ink jet printer of full colors and has good color tones of printing by laminating a hydrophilic surface layer on a protective layer subjected to printing of a white color. SOLUTION: The film of a recording layer is formed by a spin coating method on a polycarbonate resin substrate having spiral grooves. An Au thin film as a reflection layer is formed by sputtering on the recording layer and the surface of the film is spin coated with a UV curing resin, following which the resin is irradiated with UV rays to form the protective layer. The surface of the protective layer is printed with the UV curing type white ink by screen printing over the entire surface. Further, the printing layer is screen printed with a resin consisting of the UV curing resin contg. org. fillers and/or inorg. fillers having water absorptivity and oil absorptivity. The resin is then cured by the irradiation with the UV rays to form the hydrophilic surface layer, by which the optical recording medium is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium, and more particularly to an optical recording medium whose surface can be written with a writing instrument, an ink jet printer or a sublimation printer.

[0002]

2. Description of the Related Art A read-only optical recording medium such as a compact disk (CD) or a laser disk (LD), which has been widely and widely used at present, stores information by an injection molding method based on a master usually called a stamper. To manufacture substrates with According to this method, it is possible to produce a medium having the same information at low cost and in large quantities, but it is not suitable for producing a small amount of a medium because the stamper is very expensive. Further, with the progress of the information society in recent years, there has been a growing demand for higher density recording than magnetic recording media. Therefore, an optical recording medium has been developed for creating a small amount of information recording medium or for allowing a user to freely record and store data.

[0003] Optical recording media are classified into two types: a write-once type, in which information can be recorded and reproduced, and a rewritable type, in which data can be erased after recording. Among them, a write-once compact disc having a single-plate structure is called a CD-R, and is a normal read-only CD.
Due to compatibility with D, the number of users is gradually increasing. After the CD-R has been purchased, it is necessary for the user to know what information is recorded on the medium in some way so that the user can write the data after purchasing the medium.

In general, a method of displaying a title or the like is a method of manually writing on a surface with an oil-based felt pen.
Handwriting is not preferred when selling media to end users after data has been entered into the DR. On the other hand, the method of attaching a paper or film label such as a proppy disk has an advantage that a printer can print a well-designed character or picture. However, if it is desired to put characters on the entire surface of the disc, it is necessary to use a donut-shaped label having a large area, and it is very difficult to affix the label in alignment. In addition, when the film is peeled, there is a possibility that the film may be peeled and caught in the apparatus, and thus another method has been desired.

[0005]

From these uses, a method of printing a recorded content using an ink jet printer or the like by applying a hydrophilic coating layer on the side opposite to the light incident surface of the medium has been put into practical use. A CD-R medium having a special surface corresponding to is available on the market. By using these, the user can freely display information on the disc on a personal computer basis, but when printing in full color, there is a problem that the color tone is printed differently reflecting the color of the reflective layer. Was.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical recording medium in which the color tone of full-color printing is improved in a recording medium having a surface corresponding to an ink jet printer.

[0007]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies. As a result, by laminating a hydrophilic surface layer on a white printed protective layer,
The inventors have found that the above problems can be solved, and have reached the present invention.

That is, the present invention relates to (1) an optical recording medium comprising at least a recording layer, a metal reflection layer, a protective layer subjected to white printing, and a hydrophilic surface layer laminated on a transparent substrate,
Further, (2) the optical recording medium according to the above (1), wherein the white printed protective layer is made of an ultraviolet curable resin, and (3) the hydrophilic surface layer is water-absorbing and / or oil-absorbing. The optical recording medium according to the above (1) or (2), comprising an ultraviolet-curable resin containing an organic filler and / or an inorganic filler having a surface, and having a printable surface.
(4) The optical recording medium according to any one of (1) to (3) above, wherein the recording layer is made of an organic dye, and (5) a color print is performed on the hydrophilic surface layer with an aqueous or oily ink. An optical recording medium according to any one of the above (1) to (4).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an optical recording medium used in the present invention comprises a transparent substrate, a recording layer, a metal reflective layer, and two or more protective layers. Layers may be stacked.

Since the substrate used in the present invention performs reproduction and recording by light, any transparent material can be used. For example, a polycarbonate resin, an acrylic resin, a polystyrene resin, a vinyl chloride resin, an epoxy resin, a polyester resin, a polymer material such as polyolefin, an inorganic material such as glass, and the like can be exemplified, but not limited thereto. Inside, the mechanical strength of the substrate, the ease of providing grooves, read-only signals, etc.,
In terms of economy, polycarbonate resin, acrylic resin,
Polyolefin resins are desirable, and polycarbonate resins are more desirable. The shape of these substrates may be plate-like or film-like, and may be circular or card-like.
Further, these substrate surfaces may have guide grooves and pits indicating recording positions, and pits for partially read-only information. These grooves and pits are usually formed by a known method using a stamper.

The recording layer used in the present invention generally uses an organic dye of a cyanine type, a phthalocyanine type or an azo type. These dyes may be substituted with various substituents for solubility in a solvent or recording characteristics. These dyes may be used alone or in combination of two or more.

The recording layer containing the dye described above can be generally formed by a coating method such as spin coating, spray coating and dip coating. When the dye is formed by a coating method, the dye may be dissolved and applied in a solvent that does not damage the resin substrate, that is, a solvent that does not substantially dissolve the resin for the substrate. In the present invention, the thickness of the recording layer is usually preferably from 50 to 200 nm. When forming a recording layer containing a dye, in addition to the above-described dye, nitrocellulose, ethyl cellulose, acrylic resin, polystyrene resin, a resin such as a urethane resin, a leveling agent, an antifoaming agent, etc. impair the effects of the present invention. It can also be used together in a range that does not exist. Although a recording layer mainly containing an organic dye is described, it is apparent that the present invention can be applied to a medium using an inorganic substance, a polymer, or a metal as the recording layer.

As the reflective layer provided on the recording layer in the present invention, a metal film having high reflectivity such as gold, silver, aluminum or an alloy thereof is used. These metal reflective layers can be formed by a method such as vapor deposition or sputtering. The thickness of these reflective layers is usually 500 to 2000 mm.
The degree is preferred. The reflective layer can be formed by multilayering.

A protective layer is provided on the reflective layer. For example, there are those which polymerize by a general radical reaction of acrylate or methacrylate, and those which perform cationic polymerization by light such as epoxy. These resins may be polymerized singly or as a mixture of monomers and oligomers. It is also possible to dilute with a solvent and apply.
Among them, an ultraviolet curing type is desirable from the viewpoint of workability. When the protective layer is formed, it is performed by a method such as spin coating, dip coating, bar coating, screen printing, etc. In many cases, the spin coating method is used from the viewpoint of workability. These thicknesses are used in thicknesses from 1 μm to 100 μm,
~ 20 μm is desirable. Not only one protective layer but also two or more protective layers may be laminated, for example, to improve the scratch resistance.

Printing is performed with a white ink on the entire surface or a part of the protective layer below the protective layer exposed on the surface. The printing is performed by a known printing method such as screen printing. The white ink is preferably an ultraviolet curable resin. The color of the ink is preferably pure white, but pinkish white or the like is sufficient.

In the present invention, the protective layer exposed on the surface is for sufficiently absorbing and fixing the ink of the ink jet printer. In particular, the protective layer is preferably composed of a hydrophilic polymer, a hydrophilic monomer, a cationic monomer and a copolymer. By making a kneaded product of a curable composition comprising a possible monomer and a radical initiator and a filler with an ultraviolet curable resin obtained by ultraviolet curing, the absorption rate of the ink is increased, and good absorption and fixing are achieved. sex,
The resolution is obtained. As the filler contained in the protective layer made of an ultraviolet curable resin exposed on the surface, an organic filler and / or an inorganic filler having a water absorbing property and / or an oil absorbing property is used.

Specific examples of the organic filler include acrylic resin, polyacrylate, polymethacrylate, styrene resin, polyester, polycarbonate,
Modified melamine resin fine particles, fine particles of polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, rubber and the like, cross-linked fine particles of these polymers, and powders of lignin, protein, cellulose and the like are also included. At this time, in order to prevent the ink of the oil-based pen or the water-based pen from repelling, it is necessary that the filler to be added has a high water-absorbing or oil-absorbing property. From this viewpoint, lignin, protein, and cellulose powders are preferred. It is particularly effective when it contains a solvent that does not easily dry, such as ink for an ink jet printer.

Specific examples of the inorganic filler include silica,
Talc, clay, calcium carbonate, calcium silicate,
Examples include barium sulfate, mica, diatomaceous earth silica, aluminum hydroxide, alumina, zirconium oxide, and zirconium hydroxide. When the silica filler is manufactured by crushing, sufficient effects cannot be obtained due to low water absorption or oil absorption. However, in the case of synthetic silica or the like in which fine primary particles are collected to form secondary particles, the solvent of an oil-based pen or an aqueous pen penetrates into the gaps between the secondary particles, which is effective.

In the case of inorganic fillers, the oil absorption is often measured. Generally, according to the JIS-K-5101 method,
It is expressed by the amount of linseed oil absorbed per 100 g of filler. In the present invention, it is preferably 5 ml / 100 g (filler amount) or more. More preferably 15 ml / 100 g (filler amount) or more.

Although there is no general method for measuring the amount of water absorption, it is desirable that the amount of water dropped into the filler when water is dropped on the filler. In the case of a filler whose surface is treated with fluorine, water droplets become spherical without being absorbed by the filler. If such a filler is used, both oily and water-based inks repel without drying. The organic filler and the inorganic filler can be used alone, but can be used together for improving the drying property after writing, adjusting the viscosity of the ink, or improving the color tone. At this time, the mixing ratio can be variously changed depending on the purpose.

A filler having a thickening action, such as Aerosil, may be added to adjust the viscosity of the ink.
Various additives can be used according to other purposes. Leveling agent, defoamer, defoamer, thickener,
Examples thereof include an anti-sagging agent, an anti-settling agent, a pigment dispersing aid, a wetting agent and a dispersing aid.

As the resin containing the filler, an ultraviolet curable resin is preferable. Solvent-containing resins such as thermosetting resins require a complicated drying step, and organic solvents released by drying are not preferable in terms of working environment. The ultraviolet curable resin is usually used without a solvent. However, when a filler is added to the ultraviolet curable resin, the amount of addition is limited due to an increase in viscosity. Therefore, the drying speed of the ink becomes slow, which is not preferable for this purpose. In order to further improve the characteristics of the resin layer, it is preferable to further devise the resin layer. That is, this resin layer contains one or more hydrophilic polymers, one or more hydrophilic monomers, one or more cationic monomers, one or more crosslinkable monomers, and radicals. An ultraviolet curable resin containing an initiator is used.

The addition of the hydrophilic polymer to the layer exposed on the surface facilitates fixing of the ink adhered to the surface. Hydrophilic polymers include homopolymers and copolymers such as polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, and the like. In the case of a copolymer, a combination with a non-hydrophilic polymer may be used. One of these may be added, or two or more may be used in combination. The more it is added, the better the ink of the pen or the printer is fixed, but the high viscosity of the resin makes it impossible to form a film or the polymer is precipitated, so the total amount of the hydrophilic polymer in the resin composition becomes 1 to 80 parts by weight Add as Preferably 10
It is good to use up to 70 parts by weight.

In the present invention, the hydrophilic polymer is dissolved in a highly polar hydrophilic monomer. Hydrophilic monomers include hydroxy (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, 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 (meth) acrylate, phenylglycidyl ether (meth) acrylate, dipentaerythritol penta (meth) acrylate, bisphenol A epoxy resin di (meth) acrylate having an OH group in the molecule, Dimethyl (meth) acrylamide, diethyl (meth) acrylamide, acroylmorpholine, N-vinylpyrrolidone, 2-ethoxyethyl (meth) acrylate,
-Highly polar substances such as methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, and glycidyl (meth) acrylate are used. It may be monofunctional or a difunctional or higher functional monomer.

These monomers uniformly dissolve a hydrophilic polymer like a solvent, and further suppress bleeding and bleeding when characters are written on a resin layer with a pen or an ink jet printer containing a large amount of an organic solvent or water. In particular, when a polymer having high hydrophilicity is used, the hydrophilic polymer is easily dissolved when a monomer having a highly polar group such as a hydroxyl group, a carboxyl group, an amino group, or an amide group in the molecule is used. In order to improve the solubility of the hydrophilic polymer, water, alcohols such as methanol, ethanol, propanol, butanol, pentanol and hexanol, ethers such as dimethyl ether, diethyl ether, methyl ethyl ether and dipropyl ether, acetone and cyclohexane And some solvents such as ketones such as dichloroethane and halogen such as chloroform. The total amount of the hydrophilic monomer in the resin composition is 20 to 88 parts by weight. Preferably, 20 to 78 parts by weight are added.

By adding a cationic monomer to the layer exposed on the surface, if a character or the like is written on the surface of the layer exposed on the surface with a pen or an ink jet printer containing a large amount of an organic solvent or water, bleeding or repelling may occur. Can be further suppressed and the resolution can be greatly improved. Particularly, a cationic monomer having a group such as an amino group or an amide group in the molecule is effective.

Examples of the cationic monomer having an amino group or an amide group include dimethyl (meth) acrylamide, diethyl (meth) acrylamide, dimethylaminomethyl (meth) acrylate, and dimethylaminomethyl (meth).
Acrylate quaternary salt, dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate quaternary salt, diethylaminomethyl (meth) acrylate, diethylaminomethyl (meth) acrylate quaternary salt, diethylaminoethyl (meth) acrylate, diethylaminoethyl (Meth) acrylate quaternary salts, methylenebis (meth) acrylate, acryloylmorpholine, N-vinylpyrrolidone and the like are used. The total amount of the cationic monomer contained in a part of the hydrophilic monomer is 1
Add to 0-70 parts by weight. Desirably 10 to 50
It is better to use parts by weight.

To these are added crosslinking monomers. These include trimethylolpropane tri (meth) acrylate, acrylated isocyanurate, 1,4 butanediol di (meth) acrylate, 1,6 hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dicyclo Pentadienyl di (meth)
Acrylate, pentaerythritol tetra (meth) acrylate and the like are used. In the case where the hydrophilic monomer is polyfunctional such as glycerin di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol hexa (meth) acrylate, it is not always necessary to add the hydrophilic monomer. By adding the crosslinkable monomer, the crosslink density of the protective layer exposed on the surface is increased, and the coating film hardness is increased. The total amount of the crosslinking monomer in the resin composition is 1 to 40 parts by weight. Preferably, 1 to 20 parts by weight is added.

When a hydrophilic polymer is added to a mixture of a hydrophilic monomer or a crosslinkable monomer curable by ultraviolet light, the viscosity increases. Addition of fillers to these mixtures further increases the viscosity. For this reason, if the viscosity of the monomer is too high, the viscosity becomes very high after the addition of the filler, and the application becomes impossible. In this experiment, it is necessary to select a UV-curable resin having as low a viscosity as possible.

To these are added a radical initiator. Examples of the radical initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-diethoxyacetophenone, 4′-phenoxy-2,2-dichloroacetophenone and the like. Acetophenones, propiophenones such as 2-hydroxy-2-methylpropiophenone, anthraquinones such as 2-chloroanthraquinone, and thioxanthones such as 2,4-diethylthioxanthone. The amount to be added at this time is 0.1 to 10 parts by weight of the resin. Preferably, it is 1 to 8 parts by weight. At this time, one photoinitiator may be used, or two or more photoinitiators may be combined.

The filler is used in an amount of 1 to 100 parts by weight of the resin.
8080 parts by weight, preferably 5-50 parts by weight. Considering storage stability, it is desirable to stir uniformly with a disper or the like. The method of forming the layer exposed on this surface includes a bar coating method, a blade coating method, an air knife coating method, a roll coating method, and a screen printing method.
The screen printing method is particularly desirable since the writability can be further improved by making the surface uneven. In the present invention, a solvent can be used for the ultraviolet curable resin in order to improve the coatability when forming the resin layer.
Although the thickness is designed to be 1 to 100 μm, the thickness is preferably 1 to 20 μm in consideration of the influence on the warpage of the disk. If a single protective layer is provided on the reflective layer, the protective layer may be provided on the entire surface of the disk or may be provided partially.

The applied resin layer is cured by ultraviolet light. When the resin layer is cured by exposure to ultraviolet light, 150 to 2000 mJ /
Give cm ² of energy. More preferably 250-10
00mJ / cm ² shed. At this time, the coating film hardens in a few seconds. UV lamps used for curing are mercury lamps, high-pressure mercury lamps,
Ultra-high pressure mercury lamps and metal halide lamps are desirable.

Layers may be further partially overlapped with portions other than portions where characters are written or printed. For example, portions other than where different titles, numbers, dates, and the like are written in each medium may be described with a common company name, mark, medium product name, software name recorded in the medium, and the like. In such a case, several layers may be further stacked by screen printing, offset printing, or the like.

When writing on the protective layer exposed on the surface configured as described above, an oil-based pen, an aqueous pen containing water or a water-soluble organic solvent, an oil-based stamp, or an aqueous stamp can be used. In addition, an ink jet printer, a sublimation printer, or a thermal transfer printer using an oil-based or water-based ink can also be used.

[0035]

The present invention will be described in detail below with reference to examples and comparative examples. In the following, “parts” are based on weight.

Example 1 An injection molded polycarbonate resin substrate having a spiral groove (depth: 140 nm, width: 0.5 μm, pitch: 1.6 μm) having a thickness of 1.2 mm and a diameter of 120 mm was coated with a phthalocyanine dye recording layer on an octane solution. A film was formed by a spin coating method using A reflective layer with a thickness of 100 on this recording layer
An Au thin film having a thickness of nm was formed by sputtering. After spin-coating Dicure Clear SD-17 (Ultraviolet curable resin, manufactured by Dainippon Ink and Chemicals, Inc.), ultraviolet rays were irradiated to form a 6 μm protective layer. A UV-curable white ink (manufactured by Dainichi Seika Kogyo Co., Ltd.) was screen-printed on this protective layer to a total thickness of 10 μm. Furthermore,
On this printed layer, 20 parts of bisphenol A epoxy acrylate, dipentaerythritol hexaacrylate
10 parts, 65 parts of N-vinyl-2-pyrrolidone, 5 parts of radical initiator Darocure 1173 to a resin having a composition of 5 parts, and an organic filler containing protein as a main component (average particle size: 10 μm) per 100 parts of the above resin. Parts, kneaded with a disper, screen-printed, and cured by irradiating ultraviolet rays to form a 15 μm hydrophilic surface layer.
R medium was used. When full-color printing was performed on the printing surface with an inkjet printer manufactured by Canon, a full-color print image having very good resolution and color tone was obtained.

Comparative Example 1 A CD-R medium was prepared in the same manner as in Example 1, except that the screen printing of the ultraviolet curable white ink was omitted on the protective layer. When full-color printing was performed on the printing surface with a Canon inkjet printer, the resolution was good, but the yellowish color was unclear and a color tone faithful to the original image could not be obtained.

[0038]

As is clear from the results of the examples and comparative examples, the medium into which the protective layer printed with white was introduced,
By combining the hydrophilic surface layer, an optical recording medium compatible with a full-color ink jet printer can be provided.

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Yasaku Kano 1900 Togo, Mobara-shi, Chiba Mitsui Toatsu Chemicals Co., Ltd.

Claims (5)

[Claims] 1. An optical recording medium comprising at least a recording layer, a metal reflective layer, a protective layer printed with white color, and a hydrophilic surface layer laminated on a transparent substrate. 2. The optical recording medium according to claim 1, wherein the white printed protective layer is made of an ultraviolet curable resin. 3. The light according to claim 1, wherein the hydrophilic surface layer is made of an ultraviolet curable resin containing an organic filler and / or an inorganic filler having a water absorbing property and / or an oil absorbing property, and the surface is configured to be printable. recoding media. 4. The recording layer according to claim 1, wherein the recording layer comprises an organic dye.
The optical recording medium according to any one of the above. 5. The optical recording medium according to claim 1, wherein the hydrophilic surface layer is color-printed with an aqueous or oil-based ink.