JP3021164U - Optical information medium - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To print a certain character or pattern on a surface of a protective layer of an optical information medium with an aqueous ink by using an ink jet method or the like while securing a protection function of recorded contents of the optical information medium. , The original color development of water-based ink is exhibited, or the degree of freedom in design is expanded without being restricted by the background color. SOLUTION: A protective layer 24 made of a resin is formed on the back surface of the translucent substrate 21 on the side where the reproduction light is incident, and is adhered through another layer, and the protective layer 24 is provided on the protective layer 24 for aqueous printing. A hydrophilic resin film 26 on which ink can be fixed is formed. On the rear surface of the hydrophilic resin film 265, the transparent substrate 21
A colored hiding layer 28 for hiding the color tone between the protective film 24 and the protective film 24 is provided. The colored hiding layer 28 exhibits the original color development of the water-based ink printed on the hydrophilic resin film 26 without being restricted by the background color, and expands the degree of freedom in design.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to an optical information medium that can be printed using printing ink on the surface opposite to the side where reproduction light is incident.

[0002]

[Prior art]

 2. Description of the Related Art At present, optical information media (hereinafter referred to as “CD”) having the name of compact disc are widely used in the fields of audio and information processing. This CD has a structure in which a reflective layer is formed by vapor-depositing gold or aluminum on a substrate made of a donut-shaped disc such as polycarbonate, and is covered with a protective layer such as an ultraviolet curable resin. Has become. The data is recorded by forming uneven pits in a spiral shape on the surface of the substrate, and the pits are formed in advance in accordance with a mold such as a stamper when molding the substrate, The reflective layer is provided thereon. Therefore, when the CD is manufactured, data is already recorded on it, and it is used as a read-only optical information medium.

In this CD, an index display showing various contents recorded on the CD and various designs are printed on the surface of the protective layer by ultraviolet curable resin ink or oil ink. These printings are performed by printing means such as screen printing or offset printing by transferring a plate. These printing means are printing means suitable for so-called high-volume printing, in which a large number of identical patterns are printed at the same time.

On the other hand, as symbolized by the so-called karaoke boom, with the increasing demand for amateurs to perform their own performances, the activities of amateur musicians to make a relatively small number of self-made CDs have become popular. These self-made CDs are made, for example, for promotion, audition, test, or self-published. In particular, a write-once type optical information medium such as a so-called CD-WO that can be recorded only once using a laser and can be reproduced by a CD player has been developed. You can now make your own CD more easily. Also, in the field of computers, so-called CD-ROMs have become widespread, and with the spread of so-called write-once type optical information media, users are likely to use their CD-WOs to make their own CD-ROMs. It has become.

Nothing is written on the protective layer of the optical information medium such as the self-made CD produced in this way, or only common characters or patterns are printed by the ultraviolet curable resin ink or the oil ink. Therefore, before or after recording personal information on the optical information medium, it is necessary to display the index of the recorded contents on the surface of the protective layer or the printing surface of the label, and if necessary, other designs. .

However, the above-mentioned printing means prints in the manufacturing process after providing the protective layer. Since both the protective layer surface and the printed surface are hydrophobic, personal information is recorded. Printing on the surface of the protective layer later requires an excessive amount of equipment, and it is difficult to print arbitrary information personally. For this reason, generally, a method of writing on the surface of the protective layer using an oil-based felt-tip pen or the like, or a means of applying a label or the like to give an indication is used. However, since it is necessary to write by hand one by one, it is bothersome, and the patterns and drawing quality drawn by hand vary, the appearance is bad, and the appearance of the optical information medium that is made is spoiled. There is a risk of scratches. In addition, when a label is attached, the display surface rises by the thickness of the label, which causes eccentricity or surface wobbling of the optical information medium during reproduction or additional recording.

Therefore, it is known to form a hydrophilic resin film on the protective layer side of the optical information medium. This is, for example, in a CD write-once where a dye layer is formed on a transparent substrate, a gold reflection film is formed on the dye layer, and a UV-curable resin protection layer is further formed on the dye layer. A white turbid hydrophilic resin film is formed on the surface, and an ink jet method is used to display with a water-based ink.

[0008]

However, even in this type of technique, the protective layer is usually transparent and the hydrophilic resin coating is transparent or semi-transparent. Therefore, the color tone on the protective layer side is lower than that of the protective layer. It is dominated by the gloss and color tone of the reflective film. For example, in the CD light once described above, when the reflective film is gold, the hydrophilic resin has a yellow appearance, and when characters or patterns are printed on the hydrophilic resin with water-based ink, the coloring of the water-based ink itself is prevented. In some cases, it may be difficult to obtain the original color. Also, in this case, the background color is restricted to yellow. For example, if you try to print a design based on red with water-based ink by the inkjet method, the hiding power of the water-based ink is weak, which is a design problem. In some cases, it may become a constraint.

An object of the present invention is to print a certain character or pattern on a surface of a protective layer of an optical information medium with an aqueous ink by using an ink jet method or the like while securing a protection function of recorded contents of the optical information medium. At the same time, it is to provide an optical information medium capable of exhibiting the original color development of the water-based ink or expanding the degree of freedom in design without being restricted by the background color.

[0010]

[Means for Solving the Problems]

 The optical information medium according to the present invention is provided with a protective layer made of a resin, which is formed by being adhered to the back surface of the translucent substrate on the side where the reproduction light is incident via another layer, and the aqueous printing layer is formed on the protective layer. In an optical information medium having a hydrophilic resin film on which a fixing ink can be fixed, a colored hiding layer for hiding the color tone between the transparent substrate and the protective film is provided on the back surface of the hydrophilic resin film. .

In such an optical information medium, information that can be optically read by laser light can be reproduced and / or recorded. A typical example of such an optical information medium is a CD or a CD write once. In this optical information medium, a character or a pattern can be arbitrarily drawn on the back side of the side where the reproduction light is incident by any writing means such as a writing tool using water-based ink or a writing tool using oil-based ink. Of course, it is also possible to use other methods such as UV curable ink.

When printing characters or a pattern on the surface of the hydrophilic resin film, a water-based ink is ejected toward the surface of the hydrophilic resin film to adhere the ink to the surface, and the water-based ink By fixing and printing on the same surface, it is possible to display on the surface of the optical information medium without damaging the protective layer or the substrate. Then, the water-based ink is fixed on the hydrophilic resin film of the optical information medium and the display is performed, so that the fixing becomes good and a display having a good appearance can be obtained. Further, since the surface is a hydrophilic resin film, fingerprints and dust are less attached and the appearance is good and handling is easy. Since the hydrophilic resin film has a sufficient thickness to fix the ink, unnecessary bleeding can be prevented and a good display can be obtained. In this way, when the surface of the hydrophilic resin film is printed with ink, the surface does not become uneven as in the case where the label is attached and the surface is marked, and the surface becomes flat, so eccentricity during reproduction or additional recording It is possible to prevent the occurrence of surface blurring. When printing on the surface of a hydrophilic resin film by ejecting ink with an inkjet printer, for example, it is possible to make characters and patterns to be printed by a personal computer in advance and print them repeatedly, so printing patterns and print quality It is possible to display characters, patterns, etc. with little variation.

Since the colored hiding layer has a color tone that hides the color tone between the transparent substrate and the protective film, the background color that should appear on the surface of the hydrophilic resin film is hidden. As a result, the hiding power of the water-based ink printed on the surface of the hydrophilic resin film can be supplemented or corrected, and the original color development of the water-based ink can be exerted or the ground color is restricted. It is possible to expand the degree of freedom in design. Preferably, the binding property of the layer boundary between the colored concealing layer and the layer adjacent thereto is better than that of the other layers constituting the translucent substrate. As a result, when the ink adheres to the surface of the hydrophilic resin film and the film expands or contracts during the drying process, the color of the colored hiding layer does not change and the ink is integrated with the protective layer. It protects the layer between the protective layer and the translucent substrate. Therefore, the recording or reproducing characteristics do not deteriorate. Further, the warp of the optical information medium and the peeling of the hydrophilic resin film are reduced, which prevents deterioration of the recording and reproducing characteristics, and also provides a highly reliable optical information medium with high weather resistance. You can

For example, the protective layer of a CD, which is a typical example of optical information medium, is often made of an ultraviolet curable resin, while the colored concealing layer is formed on the protective layer made of this ultraviolet curable resin layer. It is preferably a provided hydrophilic ultraviolet curable resin film. In particular, after UV-curing the protective layer, UV-curable ink for the colored concealing layer is provided on this protective layer, and when this is UV-cured, the binding property of those layer boundaries is It is better than the bondability of the layer boundaries of the other layers constituting the. Further, since such a colored hiding layer can be formed by the same process (for example, screen printing) as the known thick film forming process, it can be easily formed. Moreover, there is little warpage or eccentricity of the optical information medium due to the effect of curing, which is effective for deterioration of recording / reproducing characteristics.

The protective layer can be formed by applying a liquid ultraviolet curable resin and then curing it by ultraviolet irradiation. This makes it possible to form the protective layer in a short time. Further, the colored hiding layer is formed by applying a liquid hydrophilic UV-curable resin and then curing it by irradiating it with UV rays, thereby performing the same step as the step of curing the UV-curable resin layer thereunder. Since it can be cured, it can be easily formed in a short time. Further, the hydrophilic resin film 26 is also formed by applying a liquid hydrophilic ultraviolet curable resin and then curing it by irradiating with ultraviolet rays, so that the hydrophilic resin film 26 is cured in the same step as the step of curing the underlying colored masking layer. Therefore, it can be easily formed in a short time by a series of line processes. In addition, the optical information medium has little warpage or eccentricity, which is effective for the deterioration of recording / reproducing characteristics. Such an ultraviolet curable ink for a colored hiding layer can be appropriately printed on a necessary portion by printing on the protective layer by screen printing, for example.

It is preferable that the colored protective layer be thinner than the hydrophilic resin layer, and that the colored protective layer be larger than the hardness of the protective layer. Then, it is possible to prevent the optical information medium from being damaged by the writing pressure when the surface is displayed with a writing instrument such as an aqueous ink. Preferably, the formed hydrophilic resin film is formed by dispersing the pigment in the hydrophilic resin, and the surface thereof is made into a fine rough surface. Then, the contact angle of the ink becomes smaller than that in the case where the surface is not rough, so that the ink adherence is improved and the printability is improved. In addition, even if the optical information medium is handled by hand, fingerprints and the like are not attached, so that it is easy to handle. In addition, because the pigment is dispersed, the coloring of the pigment in the hydrophilic resin and the coloring concealing layer combine to allow the original color development of the water-based ink to be further exerted, or there is no restriction on the design without being restricted by the ground color. It becomes possible to expand the degree.

[0017]

[Embodiment of device]

 FIG. 1 is a view of the optical information medium as seen from the back surface side of the surface on which the reproduction light is incident, and the translucent substrate 21 is on the lower surface side in the figure. As shown in this figure, a hydrophilic resin film 26 is formed on the surface of the ultraviolet curable resin layer 25. The hole provided at the center of the optical information medium is a clamp hole 4 for clamping with the clamper of the spindle when the optical information medium is set in the CD player. FIG. 2 schematically shows a cross section of the AA portion of the optical information medium of FIG. 1, and the thickness direction is exaggerated for convenience of drawing. Further, FIG. 3 schematically shows an enlarged cross section of a so-called write-once type optical information medium as an example of this optical information medium.

A guide groove 22 for tracking is spirally formed on a transparent substrate 21 made of a polycarbonate resin or the like, and a dye recording layer 23 is coated on the guide groove 22. A reflective layer 24 made of a metal film of gold, silver, aluminum or the like is formed on the dye recording layer 23, and a protective layer 25 is provided thereon. Further, a colored hiding layer 28 described later is provided on the protective layer 25, and a hydrophilic resin film 26 described later is formed thereon. FIG. 4 schematically shows a further enlarged cross section of the display portion of the optical information medium. A hydrophilic resin film 26, which will be described later, formed on the protective layer 25 fixes an ink 27 such as an aqueous ink. Has been done.

FIG. 6 is a sectional view showing a main configuration of a printing apparatus for performing ink jet recording on the hydrophilic resin film 26 of such a write-once type optical information medium, and FIG. It is a holder 31 for holding the optical information medium 2 when performing ink jet recording with another device. The holder 31 has a rectangular shape, and a circular hole 33 that is slightly larger than the outer diameter of the optical information medium 2 is provided in the center of the holder 31. Inside the holder, a step portion 32 that holds the outer peripheral edge of the optical information medium 2 is formed. It is provided. The depth of this step portion 3 is slightly shallower than the thickness of the optical information medium 2. Therefore, as shown in FIG. 5, the optical information medium 2 is fitted into the hole 33 of the holder 31 with the hydrophilic resin film 26 side facing upward, and the outer peripheral portion of the optical information medium 2 on the incident surface side of the reproduction light is set. When supported by the step portion 32, the optical information medium 2 is held by the holder 31 so that the surface of the hydrophilic resin film 26 thereof is slightly above the surface of the holder 31.

The optical information medium 2 held by the holder 31 is extended on the feeding table 41 of the printing apparatus shown in FIG. 6, and the rollers 42 and 43 are fed to a position where they hit the end portions of the holder 31. When a print signal is input to the printing apparatus from a computer or the like, the rollers 42 and 43 are driven to start feeding the holder 31. A print head 44 is arranged right above the position where the optical information medium 2 passes over the table 41, and particles of printing ink are ejected from the print head 44 onto the surface of the hydrophilic resin film 26 of the optical information medium 2. , Characters and designs are printed on the surface of the film 26.

As described above, the printing apparatus shown in FIG. 6 is an inkjet printer that performs inkjet printing. In this type of printer, as is well known, a plurality of thin print nozzles are arranged in the print head 44. This print nozzle, for example, causes a bubble to be generated in the ink in the print nozzle by an electrothermal converter that operates by an electric signal, and ejects the ink from the tip of the nozzle. As a result, as described above, the ink is attached to a predetermined position on the surface of the hydrophilic resin film 26 of the optical information medium 2 which is conveyed along the feeding table 41.

The plate-like transparent substrate 21 used in the optical information medium 2 is a highly transparent material having a refractive index in the range of 1.4 to 1.6 with respect to laser light, and is excellent in impact resistance. Resin is used. Specific examples thereof include polycarbonate, polyolefin, and acrylic, but are not limited thereto. The transparent substrate 21 is molded using such a resin material, for example, by a method such as an injection molding method. As shown in FIG. 3, a spiral guide groove 22 or a tracking guide means having another shape may be provided on the surface of such a transparent substrate 21. Such tracking guide means can be formed by a known method using a stamper.

This optical information medium is provided with at least one of a portion for recording information optically readable by a laser beam or a recorded portion, which is, for example, irradiated with a laser beam. Therefore, it means a layer capable of optically reproducing or recording information, or a substrate surface or another surface involved in recording or reproduction. For example, in the case of the aforementioned write-once type optical information medium shown in FIGS. 1 to 3, the dye recording layer 23 formed on the translucent substrate 21 and the reflection layer 24 formed on the dye recording layer 23 form the information. Enables recording and playback of. On the other hand, in a read-only optical information medium such as a CD in which a light-reflecting layer and a protective layer are sequentially stacked on a substrate, a pit row formed on the light-transmissive substrate 21 and a reflecting layer covering the pits are used to store information. Play.

The recording / reproducing system is generally an optical laser beam only or a magneto-optical recording / reproducing system. Recording and reproduction of such information is performed from one side of the optical information medium, and specifically, by such means as making laser light incident from the front side of the transparent substrate 21. No optical information is recorded or reproduced from the other surface side. When laser light is used as the recording light and the reproducing light, a laser light having a wavelength of 770 to 830 nm is generally used, but a laser light having a wavelength other than this may be used.

Further, in addition to the dye recording layer 23 and the reflective layer 24 shown in FIG. 3, another layer may be provided. For example, a layer for improving reliability in addition to recording information such as a layer for improving binding property may be provided. Furthermore, an oxidation resistant layer that prevents the light reflecting layer 24 from oxidizing can be interposed between the light reflecting layer 24 and the protective layer 25. Further, in FIG. 3, the recording layer 23 is directly deposited on the transparent substrate 21, but other layers may be provided therebetween.

The protective layer 25 is a layer that protects the information recording portion against physical or mechanical damage received from the side opposite to the transparent substrate 21, and is provided on the side opposite to the transparent substrate 21 side. . For such a protective layer 25, a resin having excellent impact resistance is desirable. For example, the hardness of the protective layer 25 is preferably 2H to 7H / Grass in pencil hardness. The heat distortion temperature of the protective layer 25 is preferably 80 degrees or higher, more preferably 100 degrees or higher. The thickness of the protective layer 25 is preferably in the range of 5 to 10 μm, and it may be composed of a plurality of layers made of different materials.

The protective layer 25 can be obtained by applying monomers and oligomers of an organic compound, which are generally polymerized to form a polymer, and then performing a crosslinking reaction. When it is obtained as an organic polymer by a cross-linking reaction, a reaction initiator is added to a mixture of monomers and oligomers of an organic heavy compound having one or more reactive acryloyl groups (-CH = CH2) in the molecule from the viewpoint of workability, It is advantageous to add a small amount of the reaction catalyst and, in some cases, dilute it with a solvent such as methyl ethyl ketone or alcohol, apply the mixture in the form of a liquid, and irradiate it with ultraviolet rays or electron beams to crosslink it. In particular, an ultraviolet curable resin is preferable because it can prevent the adverse effect on the substrate and the information layer when forming the protective layer 25 and can be formed in a short time.

As such an ultraviolet curable resin, a known ultraviolet curable resin can be applied as long as it is used for an optical information medium. Specific examples thereof include resins such as N-vinylpyrrolidone, tripropylene glycol diacrylate, trimethylolpropane triacrylate, and hexanediol diacrylate. However, the method of cross-linking is not limited to the above-mentioned ultraviolet irradiation, and may be a method in which cross-linking proceeds by heat such as an epoxy resin or a urethane resin, or a dialkoxysilane coupling agent. Further, the polymerization reaction may be promoted by moisture in the air.

The main chain and side chains of the crosslinked product thus obtained may be a saturated or unsaturated linear hydrocarbon or may contain a cyclic compound such as melamine or bisphenol. In addition, a polyether containing one or more ether bonds in the main chain or side chain of the crosslinked product, a polyester containing an ester bond, a polyurethane containing a urethane bond, an ionomer containing an ionic bond, a polyamide containing an amide bond, an imide. Other bonds exemplified by polyimide having a bond, polysulfone having a sulfone bond, polysulfide having a sulfide bond and the like may be contained. It may be a copolymer compound containing two or more of these bonds, or may be a block polymer.

In order to improve the moisture resistance of these crosslinked products, a side chain may contain fluorocarbon or the like, and an epoxy resin may be contained in order to prevent deterioration due to hydrogen halide. In order to improve the adhesion between the protective layer 25 and the light reflection layer 24 or the hydrophilic resin film 26, the side chain of the crosslinked product contains a hydroxyl group, a carboxyl group, an acrylic group, an amino group, a vinyl acetate group or the like. The main chain or side chain may contain a basic acid.

When forming the protective layer 25, in addition to the resin and its reaction agent, reaction initiator, etc. during coating, a solvent and a diluent may be contained in order to improve coatability. Further, in order to stabilize the coating film, a leveling agent, a plasticizer, an antioxidant, an antistatic agent, etc. may be contained. If necessary, it may be colored with a pigment or a dye.

Curing of the resin can be changed depending on the crosslink density of the crosslinked structure or the concentration of the reactive acroyl, and also depends on the degree of freedom of molecular rotation of the oligomer itself which can be the main chain. If the shrinkage rate of the protective layer 25 during curing is lowered, cracks are less likely to occur in the protective layer 25 even when a heat cycle test is performed after curing the protective layer 25 so that no resin strain remains. Considering mechanical strength, the shrinkage rate is preferably 12% or less, and more preferably 10% or less. The protective layer 25 may be formed by laminating a resin material on the light reflection layer 24 without using a means such as coating. Further, the material is not limited to an organic compound, and an inorganic material may be formed by a known means such as a sputtering method or a vapor deposition method.

The colored masking layer 28 is a colored layer that masks the color tone between the light-transmitting substrate and the protective film, but is not limited to a layer that completely masks the color tone of the underlayer. The color tone of may be emphasized or weakened. If it is colored, it may be translucent. A commercially available ink can be used as the material of the colored hiding layer 28, and in particular, a commercially available ultraviolet curable ink is applicable. By combining this with the color tone between the light-transmitting substrate of the underlying optical information medium and the protective film, it is possible to improve the color developability of the water-based ink and to color the underlayer itself.

As such an example, for example, a white ink (SSDF27 manufactured by Dainippon Ink and Chemicals, Inc.) is used as a colored concealment layer in an optical information medium using gold as a reflective film, and a white turbid hydrophilic property is used. By forming a resin film, the black water-based ink is made to have an original color, or by using a rat color ink (SSD 548 manufactured by Dainippon Ink and Chemicals, Inc.) to form a cloudy white hydrophilic resin film, Colored water-based ink can be used as the original color, or red or blue ink (SSD 158 or 182 manufactured by Dainippon Ink and Chemicals, Inc.) can be used to change the ground color (yellow in this case) to red or blue. By using the background color of, it is possible to improve the design.

In the case of a light transmitting optical information medium as a whole, the color tone of the light transmitting substrate side can be changed, and the appearance and design can be improved. In the present invention, considering the binding property, shrinkage ratio, thickness and hardness of the protective layer and the hydrophilic resin film among the commercially available UV curable inks, the ink should be colored so that the desired color tone is achieved. Prepare and apply. At this time, the normal thickness is preferably about 5 μm to 15 μm. The binding property, shrinkage ratio, and hardness are determined in consideration of the protective layer and the hydrophilic resin film.

Further, in this optical information medium, the hydrophilic resin film 26 is formed so that the printing ink can be fixed on the surface opposite to the reading laser light incident side. The hydrophilic resin film 26 is a resin film having sufficient hydrophilicity to fix the ink to the extent that the ink does not bleed even if the aqueous ink is dropped and touched with a hand after 30 minutes. That is, it means a film on which ink can be fixed to the extent that it cannot be easily erased, rather than the state where the ink is simply attached by drying the ink. The ink printed on the hydrophilic resin film 26 is fixed on the surface of the hydrophilic resin film 26 with almost no reduction in the adhesion area. The display thus fixed has a flat surface. The term "flat" as used herein means that there is substantially no difference in surface roughness between the display portion and the non-display portion.

The hydrophilic resin film 26 may be provided over the entire surface of the protective layer 25. However, as shown in FIGS. 1 and 2, for example, the hydrophilic resin film 26 may be provided excluding the inner and outer edge portions of the protective layer 25. it can. Further, the hydrophilic resin film 26 is provided on a plane between the protective layer 25 and the light-transmissive substrate 21, for example, inside the reflection layer 24, that is, on the inner side of any of the inner and outer peripheral edges thereof. It is preferably formed. More preferably, as shown in FIG. 2, it is preferable that the hydrophilic resin film 26 is formed on a plane in a region inside both the inner and outer peripheral edges of the reflective layer 24 and the like. However, for example, when the protective layer 25 extends to the outer peripheral edge surface of the transparent substrate 21 and is directly adhered to the peripheral surface, the transparent substrate 21 and the protective layer 25 are bonded at the outer peripheral edge. Since the adhesiveness is extremely good, in such a case, the hydrophilic resin film 26 may be formed outside the outer circumference of the reflective layer 24 or the like.

Examples of such a hydrophilic resin include, for example, polyethylene oxide (polyethylene oxide), polyvinyl alcohol (polyvinyl alcohol), polyvinyl methyl ether (polyvinyl formal carboxyl), and the like. Polymer (Carboxyvinyl Polymer), Hydroxyethyl Cellulose (Hydroxyethyl Cellulose), Hydroxypropyl Cellulose (Methyl Cellulose), Sodium Carboxymethyl Cellulose (Carboxymethyl Cellulose) ulose), polyvinylpyrrolidone, morpholine, ketone formaldehyde, styrene / maleic anhydride copolymer, shellac, dextrin, poly (acrylic acid pyrrolidonyl ethyl ester), polyacrylic acid and metal salts thereof. , Polyamine, polyacrylamide, polyethylene glycol, polydiethylaminoethyl (meth) acrylate, polyhydroxystyrene, polyvinyl alkyl ether, polyvinyl hydroxybenzoate, polyphthalic acid, cellulose acetate hydroxydiene phthalate, for example, the main chain is methyl methacrylate and the side chain is N- Graft polymers such as LH-40 (manufactured by Soken Chemical Industry Co., Ltd.) consisting of methylol acrylamide, water-soluble alkyd Examples thereof include water-soluble polyester, water-soluble polyester, water-soluble polyepoxy, polyamide, polyvinyl methyl ether, saponified polyvinyl acetate, carboxymethyl cellulose, carboxymethyl cellulose sodium salt, gum arabic, guar gum and sodium alginate. At least one kind of these hydrophilic resins is prepared, and a photopolymerizable monomer and a photoinitiator described below and, if necessary, other additives are mixed and coated.

These resins are mixed by adjusting the blending balance in consideration of the reliability of the optical information medium such as weather resistance, water resistance, warpage, and manufacturability. The hydrophilic resin may be added in an amount of 5% by weight or more and a solubility limit (for example, 50% by weight) based on the total amount of the liquid, but it is preferably in the range of 5 to 20% by weight. If it is too large, the water resistance will be poor and the printing workability will also be prone to deteriorate. If the amount is too small, the wettability of the ink deteriorates, and the bleeding after printing tends to occur.

It is desirable to add a photopolymerizable monomer to the hydrophilic resin. Further, a hydrophilic photopolymerizable monomer may be used instead of the above resin. Examples of hydrophilic photopolymerizable monomers include polyether-modified mono (meth) acrylate, (meth) acrylamide derivative, amino group-containing mono (meth) acrylate, hydroxyl group-containing mono (meth) acrylate, and phosphate group. And at least one monomer selected from nitrogen-containing cyclic vinyl monomers. Specifically, diethyl acrylamide, dimethyl acrylamide (SN-SX-2833: manufactured by San Nopco), polyethylene, mono (meth) acrylate having a glycol unit, alkyl-substituted (meth) acrylamide, alkoxy-modified (meth) acrylamide, methylol. Modified (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyhydric alcohol diglycidyl ether Mono (meth) acrylate, alkylene oxide-modified phosphate mono (meth) acrylate, caprolactone-modified phosphate mono (meth) acrylate, acryloylmorpholine, N-vinyl oxazoli Emissions, N- vinyl succinate imide, N- vinylpyrrolidone, and at least one monomer selected from among N- vinylcaprolactam. Further, in order to improve photocurability, (meth) acrylic acid esters of polyhydric alcohols and alkylene oxide adducts thereof, polyhydric alcohol diglycidyl ether di (meth) acrylate, etc. are used. These are appropriately added in an amount of about 50 to 100% by weight. That is, only the hydrophilic photopolymerizable monomer may be used.

A photoinitiator is added to these to obtain an ultraviolet curable resin. Specific examples of the photoinitiator include acetophenone, benzophenone, Michler's ketone, benzylbenzoin, benzoin ether, benzoylbenzoate, benzyldimethylketal, 1-hydroxycyclohexylphenylketone, thioxanthones, benzyl, 2-ethylanthraquinone, methylbenzoylformate, Diacetyl etc. can be illustrated. These photoinitiators are appropriately added in an amount of about 1 to 8% by weight, preferably 2 to 6% by weight. If the amount of the initiator is too large, the printing workability tends to deteriorate, and if the amount is too small, the curing time is long and the productivity is low, or the ultraviolet curability cannot be obtained. The resin may be mixed with the photopolymerizable monomer in order to adjust the viscosity.

Additives may be separately added to the hydrophilic UV-curable resin material. For example, it is also desirable to add a water-absorbing pigment, a wetting agent, an antifoaming agent, a surface tension adjusting agent, and the like. Specifically, fine powder of silica, talc, mica, calcium carbonate, titanium oxide, zinc oxide, colloidal silica, carbon black, red iron oxide, etc., fine powder of carboxymethyl cellulose, dextrin, methyl cellulose, etc., and special coating. , Polyvinylpyrrolidone insoluble in amide acrylates, vinyl acrylate copolymer (Sumikagel SP-510: manufactured by Sumitomo Chemical Co., Ltd.), organic pigments such as collagen powder, and known anionic or nonionic wetting agents (Nopco 2272RSN, Nopco Wet 50, Nopco Wet SN20T: all made by San Nopco), antifoaming agent (Nopco 8034: San Nopco, Dehydran 1620: Henkel, AD9301: Mitsubishi Rayon), surface tension adjusting agent (Perenol s43, the same) 5: Henkel), it can be exemplified thickeners such as polyethyleneimine (SP103 days the catalyst Corporation). The water-absorbing pigment as an additive plays a role of adjusting the printability of the ink and the workability in forming the hydrophilic film. Wetting agents can improve wettability, control fluidity, and obtain low foaming properties, and can be installed in equipment similar to other layer forming processes during the manufacturing process of optical information media such as screen printing. It is possible to improve the manufacturing efficiency. An antifoaming agent and a surface tension adjusting agent can form a coating film evenly.

The hydrophilic resin film 26 can be made opaque or cloudy or colored with a pigment. By doing so, it is possible to select an optical information medium suitable for the color of the ink and the degree of printing, and it is possible to improve the aesthetic appearance. It is also possible to make a relief pattern by forming a so-called blank part by utilizing the color of the layer provided under the protective layer. It is preferable that the hydrophilic resin does not contain water, ethyl alcohol, isopropyl alcohol, ethylene glycol, ethyl cellosolve, dimethylformamide, or other solvent. The solvent may attack the protective layer below and the UV curable resin, resulting in a decrease in reliability. Further, if a solvent is contained, the viscosity when forming the hydrophilic resin film is changed by means of screen printing or the like, which causes inconvenience in manufacturing.

The thickness of the hydrophilic resin film 26 is preferably in the range of 5 to 30 μm in order to prevent the recording / reproducing characteristics of the optical information medium from being affected. Such a film thickness can be obtained by appropriately blending the above materials to adjust the viscosity and the like. Further, the hydrophilic resin film 26 can be made thicker than the protective layer 25 to enhance the cushioning effect. The hydrophilic resin film 26 is preferably formed on the protective layer 25 made of an ultraviolet curable resin. In particular, by forming the hydrophilic resin film 26 immediately after forming the ultraviolet curable resin film as the protective layer 25, that is, before completely curing the ultraviolet curable resin as the base, these layer boundaries are formed. The binding property can be improved together.

The bondability of the layer boundary between the hydrophilic resin film 26 and the protective layer 25 is preferably better than the bondability of the layer boundary of other layers constituting the translucent substrate. Such binding property can be obtained by appropriately selecting the combination of the resin material forming the protective layer 25 and the hydrophilic resin material thereon and adopting the film forming method as described above. For example, as shown in FIG. 3, a substrate has a dye recording layer 23 and a metal reflection film 24, and a protection layer 25 made of an ultraviolet curable resin such as an epoxy resin or an acrylic resin is provided on the reflection film 24. In the case of an information medium, by providing a hydrophilic ultraviolet resin film containing an amide acrylate and polyvinyl pyrrolidone as the hydrophilic resin film 26, the above-mentioned binding property can be obtained. If the layer boundary between the protective layer 25 and the hydrophilic resin film 26 has a good binding property, even if the hydrophilic resin film 26 is formed only on a part of the surface of the protective layer 25, the hydrophilic resin film 26 is hard to be peeled off. Demonstrate the protection function of optical information media. Further, warping and peeling of the optical information medium are reduced, and deterioration of recording and reproducing characteristics is prevented.

From the viewpoint of protecting the optical information medium against writing pressure, printing pressure, etc., the hardness of the hydrophilic resin film 26 is smaller than the hardness of the protective layer 25. For example, the hardness of the protective layer 25 described above in terms of pencil hardness. It is desirable that it is smaller than 2H to 7H / Grass. Such shrinkage rate and hardness depend on the number of functional groups of the monomer that is mixed in the ultraviolet curable resin that forms the protective layer 25 and the hydrophilic resin film 26 that is formed thereon. It can be obtained by appropriately selecting a monofunctional monomer or a monomer having about 2 functional groups as the hydrophilic resin according to the physical properties of the above. By doing so, it is possible to prevent deterioration of reliability as an optical information medium such as warpage and peeling, and stable recording and reproduction can be performed.

It is preferable that the surface of the hydrophilic resin film 26 be a fine rough surface. Due to this fine surface state, when the print ink adheres to the surface 2 of the protective layer 25, the print ink is formed in the fine recesses. A so-called anchoring effect is provided, in which is retained and fixed. In addition, the surface area of the hydrophilic resin film 26 is increased by the rough surface, and ink absorption can be promoted. The rough surface referred to here is one having a contact angle with respect to the water-based ink smaller than that in the case where the surface is not rough, and preferably the average roughness (Ra) measured by a stylus type surface roughness measuring device is 2. It is preferably about 0 to 0.1 μm. Although the effect of this surface roughness on the water-based ink varies somewhat depending on the physical properties of the film, generally, if the surface roughness is small, the fine line can be drawn with good resolution, but the ink is solidly printed. When formed, it may cause blurring, and if the surface roughness is too large, both fine lines and solids are likely to bleed. In particular, by setting the average roughness (Ra) to about 1.0 to 0.5 μm, both fine line printing and solid printing can be practically satisfactorily printed.

Such a fine rough surface of the hydrophilic resin film 26 can be formed by gravure-coating the surface of the protective layer 25 with a hydrophilic ultraviolet ray curable resin. It can also be formed by coating a resin in which 2 is mixed with a filler by screen printing or spin coating. For example, when an organic or inorganic pigment is dispersed as a filler in a hydrophilic resin, a rough surface can be easily formed and its anchoring effect is great. It is suitable that the particle size of the pigment is about 1 to 10 μm, and particularly, if the particle size is 3 to 5 μm, the solid printability becomes good. The ink applicable to the optical information medium of the present invention is preferably water-based ink, but may be oil-based ink, ultraviolet curable ink, or the like.

As described above, when characters or the like are printed on the surface 2 of the hydrophilic resin film 26, writing or screen printing can be used, but it is particularly preferable to print with an inkjet printer. As is well known, an inkjet printer is used as a printer for a personal computer or the like, and it is possible to repeatedly print a printing character or a printing pattern created by a computer on the surface of the hydrophilic resin film 26. Therefore, it is suitable for printing a certain character or pattern on a relatively small number of optical information media. Further, since it is not necessary to apply an occasional impact such as hitting or heat for fixing the printing ink during printing, the optical information medium is not damaged. Similarly, it goes without saying that it can be applied to a so-called bubble jet method of forming and printing ink particles by the bubble jet method of heating the nozzle portion with a heater.

[0050]

【Example】

Next, a more specific embodiment of the present invention will be described. A guide groove having a width of 0.8 μm, a depth of 0.08 μm, and a track pitch of 1.6 μm for spiral tracking guide by a stamper is formed in a diameter range of 46 to 117 mmφ, an outer diameter of 120 mmφ, an inner diameter of 15 mmφ, and a thickness. A 1.2 mm polycarbonate substrate (Iupilon: manufactured by Mitsubishi Gas Chemical Co., Ltd.) is prepared. The hardness of this substrate was pencil hardness HB, and the coefficient of thermal expansion was 6 × 10 ⁻⁵ / ° C. at 20 to 120 ° C.

0.65 g of 1,1, -dibutyl 3,3,3,3, tetramethyl 4,5,4,5, -dibenzoindodicarbocyanine perchlorate (manufactured by Japan Photosensitive Dye Research Institute) was added to diacetone. The dye recording layer was formed by dissolving in 10 ml of alcohol, spin-coating this on the above-mentioned substrate while appropriately changing the rotation speed so that the average film thickness was 130 nm, and drying. Gold was sputtered on this to form a reflective layer having a thickness of 100 nm. Further, unnecessary portions of the dye film and the metal film were removed, and the dye film and the metal film were concentrically formed in the range of φ42 to 118.

Next, an ultraviolet curable resin (SD-17: manufactured by Dainippon Ink & Co.) containing a polyfunctional acrylate monomer as a main component is applied by a spin coating method, and 230 mj / cm ² of ultraviolet rays are irradiated with a high pressure mercury lamp to cure the resin. Thus, a protective layer having a thickness of 10 μm was formed. The hardness of the protective layer made of this ultraviolet curable resin is a pencil hardness of 5H / on glass (2H / on PC). Further, as a colored concealing layer, a white UV curable resin (SSD F27, Dainippon Ink and Chemicals, Inc.) was applied within a range of an inner diameter of 22 mm and an outer diameter of 119 mm, and an output of 120 W / cm of ultraviolet rays was irradiated for 2 m / min for curing to obtain a film having a thickness of 10 μm. The bondability between the colored hiding layer and the layer adjacent thereto was higher than that between the substrate and the dye layer, between the dye layer and the reflective layer, and between the reflective layer and the protective layer. This evaluation was performed by a cross-cut adhesive tape peeling test. Further, as a result of comparison of hardness by a pencil hardness test, it was found that the colored hiding layer had lower hardness.

On such a colored hiding layer, a monofunctional UV-curable amide-based acrylate (SN5X-2833: manufactured by San Nopco) containing a photoinitiator as the A component, and as the C component, is bifunctional. 10% by weight of powdered polyvinylpyrrolidone (K90: manufactured by Tokyo Kasei Kogyo Co., Ltd.) was blended as a component B into a liquid containing polyethylene glycol diacrylate (SN5 X-29111: manufactured by San Nopco) having a molecular weight of 400, which was sufficient. After dissolution and mixing, as component D, finely divided silica (XR37 B: manufactured by Tokuyama Enda, component D) with a particle size of approximately 4 μm in this liquid, or as a D ′ component, a particle size of approximately 4 μm with an insoluble coating on the surface UV curable resin particles (KOLIDON CLM: manufactured by BASF) were blended in the following proportions, and these were mixed into a ball mill containing 12 balls in 21 pots. There was dispersed over 24 hours to prepare a hydrophilic resin solution. Example 1 A component: B component: C component: D Component = 67:15: 5:13 Example 2 A component: B component: C component: D'component = 65:15: 5:15 Example 3 A component : B component: C component: D component = 57: 15: 15: 13 Example 4 A component: B component: C component: D'component = 50: 15: 20: 15

After forming the protective layer, a 300-mesh screen was used, and the hydrophilic resin solution was concentrically screen-printed on the φ44 to 117 portions on the protective layer under the same conditions as the protective layer. By irradiating with ultraviolet rays, a hydrophilic resin film having a thickness of 15 μm was formed. Table 1 shows changes with time in the viscosity of the hydrophilic resin solutions used in Examples 3 and 4 among Examples 1 to 4. Further, in order to compare the shrinkage rates, both the ultraviolet curable resin used for the protective layer and the hydrophilic resin were applied on a polyethylene terephthalate film having a thickness of 10 μm to a thickness of 15 μm and cured by irradiation with ultraviolet rays. As a result, the ultraviolet curable resin used for the protective layer was more flexible than the hydrophilic resin film. That is, the shrinkage rate of the ultraviolet curable resin used for the protective layer is higher than that of the hydrophilic resin film.

[0055]

[Table 1] ────────────────────── Viscosity (cps) 6 days after mixing 13 days after ──────────── ────────── Example 3 74000 98000 93000 Example 4 40600 48600 42000 ──────────────────────

The surface state of the hydrophilic resin film thus formed is a semi-transparent rough surface, and this surface roughness (Ra) is measured by a stylus-type surface roughness measuring device (DEKTAK3030: B-Coin Instruments Inc.). It was found to be 0.9 to 0.6 μm. The hardness of the resin was a pencil hardness of 4 H / on glass (2 H / on PC). By irradiating the optical information medium thus obtained with a semiconductor laser having a wavelength of 780 nm modulated into an EFM signal at a power of 7.8 mW and a linear velocity of 1.4 m / sec along a guide groove, a predetermined amount is obtained. Optical information was recorded.

Thereafter, these optical information media were subjected to an accelerated deterioration test at a temperature of 70 ° C. and a humidity of 85% RH. When the surface of the hydrophilic resin film was confirmed 100 hours after the start of the test, no change from the initial state was observed. For comparison, an OHP sheet for inkjet printing was also subjected to the same accelerated deterioration test. As a result, spots like melted spots were found in some places on the surface 100 hours after the start of the test. Furthermore, in this accelerated deterioration test, before the test (initial), 24 hours after the start of the test, and 100 hours after the start of the test, an inkjet printer was used to print with water-based black ink at different locations, and inkjet printing was performed. The performance (IJP performance) was examined. In other words, you can print "●" or "■" with an inkjet printer to see if it is possible to print without forming a mesh, and you can print Chinese characters that have a large number of strokes, and you can print without squeezing between the lines. The kanji printability was checked. The results are shown in Table 2.

[0058]

[Table 2] ────────────────────────────────── Initial 24 hours after 100 hours ───── ───────────────────────────── Example 1 Solid printability Slightly faint − Kanji printability that is more faint than the initial printability − Good Example 2 Solid printability-Slight blurring from initial stage-Kanji printability is good-Good Example 3 Solid printability is good Good Good Kanji printability is good Good Example 4 Solid printability is good Good Slightly kanji printability is good Good Good OHP sheet Solid printability Blurred-like initial (76 hours) Good kanji print-like initial (76 hours) ──────────────────────────── ──────

Table 3 shows the results of examining the IJP performance before and after the accelerated deterioration test of Example 3 and Example 4 at a temperature of 70 ° C. and a humidity of 3% RH (DRY).

[0060]

[Table 3] ─────────────────────── Initial 100 hours later ─────────────────── ──── Example 3 Good solid printability Good Good Kanji printability Good Good Example 4 Solid printability Good Slightly blurred Kanji printability Good ─────────────────── ────

Table 3 shows the warp angle of the optical information medium measured before and after the accelerated deterioration test of Example 3 and Example 4 at the temperature of 70 ° C. and the humidity of 30% RH (DRY). Also, the warp angle after leaving it for 98 hours under standard conditions of temperature 23 ° C. and humidity 50% RH is also shown in Table 4. The warp angle was measured in the radial direction at a position with a radius of 55 mm from the center according to the CD standard, and the average value thereof was shown. The comparative example has a protective layer having a thickness of 25 μm and does not have a hydrophilic resin film. In both cases, the angle is 0.6 ° or less specified by the CD standard.

[0062]

[Table 4] Table 4 ──────────────────────────── Warp angle (°) Initial 100 hours later Standard conditions (98 hours) ─ ─────────────────────────── Example 3 0.05 0.18 0.13 Example 4 0.02 0.17 0. 15 Comparative Example 0.02 0.17 0.15 ─────────────────────────────

Furthermore, the ink jet printer was used to print on the surface of the hydrophilic resin film of the optical information medium for the IJP test as described above, and this was printed at a temperature of 70 ° C., a humidity of 85% RH and a temperature of 70 ° C. for 8 hours, and a humidity of 70 ° C. When an accelerated deterioration test was conducted for 100 hours under the condition of 30% RH (DRY) and the print fading and bleeding were confirmed, almost no bleeding or bleeding could be seen. Further, after printing on the surface of the hydrophilic resin film, the printed surface was rubbed by hand three minutes later, but no scratches or the like occurred. In order to compare the binding property between the protective layer and the colored hiding layer and between the colored hiding layer and the hydrophilic resin film with the binding properties of other layers, a peeling test (cross-cut test) was performed and It was 97/100 in the layer portion, whereas it was 100/100 in the colored hiding layer portion and the hydrophilic resin film portion. The black inks of the examples were able to obtain favorable color development in any case.

[0064]

[Effect of device]

 As described above, the optical information medium according to the present invention is provided with the colored masking layer of the color tone for hiding the color tone between the transparent substrate and the protective film, so that it is not controlled by the background color of the background. In addition, when the water-based ink is printed, the original color development of the water-based ink can be exhibited, or the degree of freedom in design can be expanded without being restricted by the background color. That is, while printing a certain letter or pattern on the surface of the protective layer of the optical information medium with the aqueous ink by using the ink jet method or the like while ensuring the protection function of the recorded contents of the optical information medium, It is possible to develop the original color or expand the degree of freedom in design without being restricted by the background color.

[Brief description of drawings]

FIG. 1 is an external perspective view of an optical information medium according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a schematic vertical sectional view of an essential part of the optical information medium according to the example.

FIG. 4 is an enlarged schematic vertical sectional view of an essential part showing a state where ink is fixed on the surface of a hydrophilic resin film of the optical information medium according to the example.

FIG. 5 is an exploded perspective view of a holder and an optical information medium used for printing on the surface of the optical information medium according to the embodiment using an inkjet printer.

FIG. 6 is a schematic sectional view of an essential part showing an inkjet printer used in the embodiment.

[Explanation of symbols]

 4 Clamp Hole 21 Translucent Substrate 22 Guide Groove 23 Dye Recording Layer 24 Reflective Layer 25 Protective Layer 26 Hydrophilic Resin Film 28 Coloring Hiding Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Takashi Ishiguro 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Induction Co., Ltd.

Claims (10)

[Scope of utility model registration request] 1. A protective layer made of a resin, which is formed by being adhered through another layer on the back surface of the translucent substrate on the side where the reproduction light is incident, and a water-based printing ink is provided on the protective layer. An optical information medium capable of reproducing and / or recording information optically readable by a laser beam having a fixable hydrophilic resin film formed thereon, wherein the transparent substrate and the protective film are provided on the back surface of the hydrophilic resin film. An optical information medium, comprising a colored hiding layer for hiding the color tone between the two. 2. The optical information medium according to claim 1, wherein a hydrophilic resin film on which a water-based printing ink can be fixed is formed on the back surface of the translucent substrate on the side where the reproduction light is incident. An optical information medium characterized in that a water-based ink is fixed on a resin film to provide a display. 3. The optical information medium according to claim 2, wherein the surface of the hydrophilic resin film on which the water-based ink is fixed and the display is provided is flat. 4. The optical information medium according to claim 1, wherein the colored hiding layer comprises a radiant energy curable resin layer. 5. The optical information medium according to claim 4, wherein the colored concealing layer is provided on a protective layer made of a radiant energy curable resin layer which is formed by being adhered to the transparent substrate via another layer. An optical information medium characterized by the above. 6. The optical information medium according to claim 4, wherein the colored hiding layer is provided on the back surface of a hydrophilic resin film made of a radiation energy curing resin layer. 7. The optical information medium according to claim 4, wherein the binding property of the layer boundary between the colored hiding layer and the layer adjacent thereto is better than the bonding properties of the other layer boundaries. Optical information medium. 8. The optical information medium according to claim 4, wherein the colored concealing layer is thinner than the hydrophilic resin film. 9. The optical information medium according to claim 4, wherein the colored hiding layer has a hardness higher than that of the protective layer. 10. The optical information medium according to claim 1, wherein
The optical information medium, wherein the surface of the hydrophilic resin film is a fine rough surface, and the rough surface is formed by dispersing a particulate pigment in the hydrophilic resin.