JPH07169100A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To effectively write and print on the surface of an optical recording medium with a water base ink or oily ink by forming a protective layer or its uppermost layer of a UV-curable resin containing a specific ingredient. CONSTITUTION:A recording layer 2, a metal reflecting layer 3 and a protective layer 4 are sequentially laminated on a transparent board 1. Further, a protective layer 5 formed out of a UV-curable resin containing an organic filler having water absorptivity and/or oil absorptivity and/or an inorganic filler is formed on the upper layer or the upper part of the layer 4. Thus, the optical recording medium the recording surface of which can be written with a writing instrument without repelling or skipping of ink, can be manufacture. Since the UV-curable resin is used, its operability is improved, and a tact time can be shortened.

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 a medium which can be written on the surface thereof with a writing instrument, an ink jet printer or a sublimation printer, and more particularly to an optical recording medium.

[0002]

2. Description of the Related Art Read-only optical recording media such as compact discs (CDs) and laser discs (LDs), which have become widespread at present, usually carry information by injection molding based on a master disc called a stamper. Produce a substrate. With this method, a medium having the same information can be manufactured inexpensively and in a large amount, but the stamper is very expensive and is not suitable for producing a small amount of medium. In addition, with the progress of the information society in recent years, there has been a strong demand for higher density recording than magnetic recording media. Therefore, to make a small amount of media, or the user can record data freely,
Optical recording media for storage have been developed.

Optical recording media are classified into two types: a write-once type capable of recording and reproducing information and a rewritable type capable of erasing data after recording. Among them, the write-once compact disc having a single plate structure is called a CD-R, and since it has compatibility with a normal read-only CD, the number of users is gradually increasing.
The CD-R is used because after purchasing a medium containing no data, the user writes various information and data unique to the user. Therefore, it is preferable that the information recorded on the medium can be seen at a glance by some method.

Generally, the method of displaying the title of the written information is by hand writing on the surface with an oil-based felt-tip pen, but after the data is put on the CD-R, the medium is sold to the end user. When it does, handwriting is not so much liked because it looks good. On the other hand, the method of sticking a paper or film label, like a floppy disk, has the advantage of printing well-designed characters and pictures on a printer, but if you want to put characters on the entire disk, use a donut-shaped label with a large area. It is necessary, and it is very difficult to align and paste. In addition, there is a drawback that if it peels off, it may be peeled off and caught in the device.

[0005]

From these applications, a hydrophilic coat layer is provided on the side opposite to the light incident surface of the medium, and an oil-based pen, a water-based pen, various printers, and ink containing a solvent is used. A method of writing with an inkjet printer or the like can be considered. By the way, commercially available OHP sheets for inkjet printers and the like are processed so that a water-based ink can be fixed by incorporating a hydrophilic polymer in a resin layer of a coating film. Furthermore, by dispersing a filler or an inorganic filler in the surface layer, the surface is made to be a fine rough surface and the printing characteristics are improved.

However, the above method is basically
Since the hydrophilic polymer is dissolved in the solvent, a long drying process is required after coating. Since the CD-R is produced with a very short takt time, as is the case with commonly used CDs, it is not preferable because it requires a long heating and drying process. Moreover, in order to shorten the takt time, a large-scale device must be prepared.

A further problem is that since the hydrophilic polymer is used by dissolving it in the solvent, the solvent resistance to the solvent used, particularly water and alcohols, is extremely low. For this reason, when the surface of the medium is accidentally wetted with water, the coating film on the surface is easily damaged and sufficient characteristics cannot be obtained. Further, when stored in a high humidity environment, the printing characteristics are drastically reduced and the printing ends. In addition to them, the big problem is
When an organic solvent is used, the method of removing the solvent by drying must be avoided from the viewpoint of work environment and air pollution problems. Therefore, the present inventors have found that it is highly desirable to form a film with a solventless UV curable resin. However, when a resin layer is formed of a usual UV curable resin, there is a problem that when a coating film having a certain degree of hardness is formed, the ink of a pen or an ink jet printer is not absorbed and is repelled.

[0008]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the resin layer protecting the recording layer or the metal reflection layer, or the surface of the protective layer is further protected. The inventors of the present invention have found that the composition of the layer provided on the scratch-resistant layer to be covered has a great influence, and have reached the present invention. That is, the present invention is an optical recording medium in which a recording layer, a metal reflection layer, one layer or two or more protective layers are sequentially laminated on a transparent substrate, and the protective layer exposed on the surface is water-absorbing. And / or an optical recording medium comprising a UV-curable resin containing an oil-absorbing organic filler and / or an inorganic filler, wherein the surface of the protective layer is printable, and also on a transparent substrate. In an optical recording medium in which a recording layer, a metal reflection layer, and one or more protective layers are sequentially laminated, the protective layer exposed on the surface contains an organic filler having water absorption and / or oil absorption. Contains U
It is an optical recording medium made of a V-curable resin, and the protective layer made of a UV-curable resin exposed on the surface is a) 1 to 80 parts by weight of a hydrophilic polymer, and b) 20 to 98 parts by weight of a hydrophilic monomer. , C) 0 to 40 parts by weight of a copolymerizable monomer, and d) 0.1 to 10 parts by weight of a radical initiator, and a light obtained by UV-curing a kneaded product of a curable composition and a filler. Is a recording medium,
The protective layer made of UV curable resin exposed on the surface is a) 10 to 70 parts by weight of hydrophilic polymer, b) 50 to 90 parts by weight of hydrophilic monomer, and c) 1 to 20 parts by weight of copolymerizable monomer. And d) an optical recording medium which is obtained by UV-curing a kneaded product of a curable composition comprising 1 to 8 parts by weight of a radical initiator and a filler, and
An optical recording medium in which the organic filler contained in the protective layer made of a UV curable resin exposed on the surface is at least one of lignin, protein and cellulose,
Further, the inorganic filler contained in the protective layer made of the UV curable resin exposed on the surface is made of synthetic silica, talc,
An optical recording medium containing at least one of clay, calcium carbonate, calcium silicate, barium sulfate, mica, diatomaceous silica, aluminum hydroxide, alumina, zirconium oxide and zirconium hydroxide, and exposed to the surface. An optical recording medium in which the protective layer made of a UV curable resin is a UV curable resin, and the total amount of the organic filler and / or the inorganic filler is 1 to 80 parts by weight with respect to 100 parts by weight of the UV curable resin. Optical recording in which the layer made of the UV curable resin exposed on the surface of the UV curable resin comprises 5 to 50 parts by weight of the organic filler and / or the inorganic filler based on 100 parts by weight of the UV curable resin. It is a medium, and a protective layer made of a UV curable resin exposed on the surface is screen-printed,
An optical recording medium formed by a bar coating method, a blade coating method, an air knife coating method, or a roll coating method, and the protective layer made of a UV curable resin exposed on the surface is UV after the protective layer is formed. An optical recording medium obtained by irradiating light and curing.

The present invention is also a surface printing method for an optical recording medium, in which ink is adhered and fixed on the surface of a protective layer made of a UV curable resin exposed on the surface of the optical recording medium. And a printing method in which the ink is water-based,
A surface printing method for an optical recording medium, wherein the ink is attached to a protective layer exposed on the surface by an inkjet printer, a sublimation printer, or a thermal transfer printer.

The present invention also provides a UV curable ink suitable for forming a printable protective layer comprising an organic filler and / or an inorganic filler having water absorbency and / or oil absorbency and the above UV curable composition. And a printable protection comprising a UV curable resin and a total of 1 to 80 parts by weight of an organic filler and / or an inorganic filler having water absorbability and / or oil absorbability per 100 parts by weight of the UV curable resin. It is a UV curable ink suitable for forming a layer, and the total amount of the UV curable resin and the organic filler and / or the inorganic filler having water absorbency and / or oil absorbability is 5 per 100 parts by weight of the UV curable resin. U suitable for forming a printable protective layer consisting of ~ 50 parts by weight
It is a V-curable ink.

The term "printable" in the present invention means that writing with various writing instruments and printing with various printers are possible. As shown in FIG. 1, the structure of the optical recording medium of the present invention comprises a transparent substrate 1, a recording layer 2, a metal reflective layer 3 and a protective layer 4, and an underlayer and further a protective layer 5 are laminated in order to improve the characteristics. You may let me.

The substrate used in the present invention can be made of any material as long as it is transparent because recording and reproduction are performed by light. For example, polycarbonate resin, acrylic resin,
Polymer materials such as polystyrene resin, vinyl chloride resin, epoxy resin, polyester resin, amorphous polyolefin, and inorganic materials such as glass can be used. In particular, a polycarbonate resin is more preferable because a resin having a high light transmittance and a small optical anisotropy is desirable. The surface of these substrates may have a guide groove or a pit indicating a recording position, or a pit for partially reproducing information or the like. These grooves, pits, etc. are usually applied when making a substrate by injection molding or casting, but the laser cutting method or 2P method (Photo-
It may be produced by the Polymer method).

The recording layer used in the present invention must be capable of recording by irradiation with laser light. This recording layer is divided into those made of an inorganic substance and those made of an organic substance. For the inorganic recording layer, a rare earth transition metal alloy such as Tb / Fe / Co or Dy / Fe / Co is used for recording by the photothermomagnetic effect. In addition, Ge ・ T which changes phase
Materials containing chalcogen-based alloys such as e and Ge / Sb / Te are used. In the case of a recording layer made of an organic substance, an organic dye is mainly used. The dye used may be a mixture of a plurality of dyes. Further, a substance other than the light absorbing substance may be added.

Specific examples of dyes used in this recording layer include macrocyclic azaannulene dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), polymethine dyes (cyanine dyes, merocyanine dyes, squarylium dyes, etc.), anthraquinone. System dyes, azurenium dyes, azo dyes, indoaniline dyes and the like. Of these, a phthalocyanine-based material having high durability and light resistance is particularly desirable. The recording layer containing the dye is usually spin coating, spray coating, dip coating,
It is possible to form a film by a coating method such as roll coating.
At this time, a dye or other substance that forms the recording layer is dissolved in a solvent that does not damage the substrate, and after coating, it is dried. Solvents used include hexane, heptane, octane,
Aliphatic or alicyclic hydrocarbons such as decane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, ethers such as diethyl ether and dibutyl ether, alcohols such as methanol, ethanol, isopropyl alcohol and methyl cellosolve A polar solvent such as halogenated hydrocarbon such as 1,2-dichloroethane or chloroform can be used. These solvents may be used alone or may be mixed.

As a method of forming the recording layer, a vacuum vapor deposition method may be used. This method is effective when the recording layer substance is difficult to dissolve in the solvent or when a solvent that does not damage the substrate cannot be selected. Various underlayers may be provided between the recording layer and the substrate for the purpose of preventing deterioration of the recording layer. For example, it is possible to use a layer made of an organic substance such as polystyrene or polymethylmethacrylate, or an inorganic substance such as SiO ₂ . These may be used alone or may be mixed. Further, two or more kinds may be laminated and used.

Au, Al, Pt, A is formed on the above recording layer.
The metal reflection layer is formed using a metal such as g or Ni or an alloy thereof. In particular, it is desirable to use gold that is stable against oxygen and water. The reflective layer is formed by vapor deposition, sputtering, or ion plating. An intermediate layer may be provided between the metal reflection layer and the recording layer for the purpose of improving the adhesion between the layers or increasing the reflectance.

A protective layer is further provided on the reflective layer.
As the resin forming the protective layer, there are, for example, those which are polymerized by a general radical reaction of acrylate type or methacrylate type, and those which are cationically polymerized by light such as epoxy type. These resins may be polymerized alone or may be mixed with monomers and oligomers. It is also possible to dilute with a solvent and apply. Among them, the UV curing type is preferable from the viewpoint of workability. When forming a protective layer,
The method is spin coating, dip coating, bar coating, screen printing or the like, but the spin coating method is often used from the viewpoint of workability. These film thicknesses are used in the range of 1 μm to 100 μm, preferably 1 to 20 μm. Although the recording layer and the reflective layer are protected by the protective layer thus formed, a stronger protective layer may be required depending on the usage conditions. At this time, a UV curable resin, a thermosetting resin, an organic substance such as a solvent-containing polymer, or an inorganic substance such as SiO ₂ can be used on the protective layer.
These may be used alone or may be mixed. Further, two or more kinds of films may be stacked and used for the purpose of improving adhesion with other layers.

After recording the data on the medium, the recorded contents are written on the surface of the medium. Usually, when writing characters on the surface of the protective layer, it is easy to use an oil-based pen or an aqueous pen. Will be repelled. Also, when writing with an ink in which a dye or a pigment is mixed in a solvent like an inkjet printer which has been used recently, the ink does not dry or the characters are blurred or repelled. In the present invention,
By adding a water-absorbing and / or oil-absorbing organic filler, an inorganic filler, or a mixture of an organic filler and an inorganic filler to the resin forming the protective layer exposed on the surface, The drying speed is increased by absorbing the solvent of the ink. In the case of a UV curable ink obtained by kneading an ordinary UV curable resin and a filler,
Since the filler is added for the purpose of forming irregularities on the surface of the coating film, adjusting the viscosity, improving the coating film strength, adjusting the color tone, etc., we do not always use fillers that have water absorption and / or oil absorption. Found out. On the contrary,
In the present invention, it is possible to absorb and fix the ink of a pen or a printer printed on the surface of the resin layer by using a water-absorbing and / or oil-absorbing filler (fix the ink by adhering the ink and drying the solvent). It has the first purpose.

Specific examples of the organic filler used in the present invention include acrylic resin, polyacrylic acid ester, polymethacrylic acid ester, styrene resin, polyester,
Examples thereof include fine particles of polycarbonate, modified melamine resin fine particles, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, rubber and the like, or crosslinked fine particles of these polymers, and powders of lignin, protein, cellulose and the like. At this time, in order to prevent the ink of the oil-based pen or the water-based pen from being repelled, the filler to be added needs to have high water absorption and oil absorption. From this point, powders of lignin, protein and cellulose are preferable. It is particularly effective when it contains a solvent that does not dry easily, such as the ink of an inkjet printer.

Specific examples of the inorganic filler include silica,
Talc, clay, calcium carbonate, calcium silicate,
Examples thereof include barium sulfate, mica, diatomaceous earth silica, aluminum hydroxide, alumina, zirconium oxide, zirconium hydroxide and the like. When the silica filler is manufactured by crushing, the water absorbing property or the oil absorbing property is low, so that a sufficient effect cannot be obtained. However, in the case of synthetic silica or the like in which fine primary particles are aggregated to form secondary particles, the solvent of the oil-based pen or the water-based pen is soaked in the gaps between the secondary particles, so that it can be effectively used.

In the case of inorganic fillers, the oil absorption is often measured. Generally, it is represented by the amount of linseed oil that is absorbed per 100 g of the filler according to the JIS K5101 method.
ml / 100g (filler amount) or more is desirable, 15m
It is more preferable that the amount is 1/100 g (filler amount) or more.

On the other hand, there is no general method for measuring the amount of water absorption, but it is desirable that water drops be absorbed by the filler when water is dropped on the filler. In the case of a filler whose surface is barely treated with fluorine, the water droplets are spherical without being absorbed by the filler. This is because when such a filler is used, both oil-based and water-based inks are repelled without drying.

In the present invention, the organic filler and the inorganic filler can be used alone, but can also be used in combination for improving the drying property after writing, adjusting the viscosity of the ink, or improving the color tone. At this time, the ratio of using both in combination can be appropriately changed depending on the purpose. A filler having a thickening action such as Aerosil may be added to adjust the viscosity of the ink. Further, various additives can be used according to other purposes. Examples include leveling agents, defoaming agents, defoaming agents, thickening agents, anti-sagging agents, anti-settling agents, pigment dispersion aids, wetting agents and dispersing agents at the time of printing.

UV curable resin is used as the resin material.
At this time, if a solvent for diluting is used, a drying step is required before curing, which is complicated, and the organic solvent released by the drying is not preferable in terms of environmental problems. The UV curable resin is usually used without a solvent, but when a filler is usually added to the UV curable resin, the addition amount is limited due to an increase in viscosity. For this reason, a water-absorbing and / or oil-absorbing filler cannot be sufficiently contained, and the drying speed of the ink printed on the surface becomes slow, which is not preferable for this purpose.

As described above, in the present invention, the resin layer is further modified in order to further improve the characteristics of the resin layer. That is, in the present invention, the resin layer contains one or more kinds of hydrophilic polymers, one or more kinds of hydrophilic monomers, one or more kinds of crosslinkable monomers, and a radical initiator. It is characterized by using a UV curing resin.

That is, by adding a hydrophilic polymer to the layer exposed on the surface, the ink printed or printed on the surface is easily fixed. Such 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 hydrophilic polymer and a non-hydrophilic polymer may be used in combination as long as the copolymer exhibits properties as a hydrophilic polymer.
These may be used alone or in combination of two or more. The more the ink is added, the better the ink fixation of the pen or printer will be, but the resin viscosity will be so high that film formation will not be possible and the polymer will precipitate, so the total amount of hydrophilic polymer in the resin composition will be 1 to 80 parts by weight. To add. Desirably, the amount is 10 to 70 parts by weight.

In the present invention, the hydrophilic polymer is used by dissolving it in a highly polar hydrophilic monomer. Hydrophilic monomers include hydroxyethyl (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) a Relate, 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, A highly polar one such as N-vinylpyrrolidone, 2-ethoxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, ethylcarbitol (meth) acrylate, or glycidyl (meth) acrylate is used. It may be monofunctional or bifunctional or higher functional.

These monomers uniformly dissolve a hydrophilic polymer like a solvent, and further suppress bleeding and repellency when writing characters on a resin layer with a pen or an ink jet printer containing a large amount of an organic solvent and water. It has an effect. Especially when a polymer having high hydrophilicity is used, the use of a monomer having a highly polar group such as a hydroxyl group, a carboxyl group or an amino group in the molecule allows the hydrophilic polymer to be more easily dissolved. Water, alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, etc., ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, dipropyl ether, acetone, cyclohexanone for improving the solubility of the hydrophilic polymer. A ketone-based solvent such as the above, a halogen-based solvent such as dichloroethane, or chloroform may be partially used. The total amount of hydrophilic monomers in the resin composition is 20 to 98 parts by weight. Desirably, 50 to 90 parts by weight are added.

In the present invention, a crosslinking monomer may be added to these. 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, dicyclopentadienyl di (meth) acrylate, pentaerythritol tetra (meth) acrylate, etc. are used. In addition,
When 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.
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 0 to 40 parts by weight. Desirably, 1 to 20 parts by weight is added.

When a hydrophilic polymer is added to a mixture of hydrophilic monomers and crosslinkable monomers that can be cured by UV light, the viscosity increases. If a filler is added to the mixture, the viscosity is further increased. Therefore, if the viscosity of the monomer is too high, the viscosity will be too high after the addition of the filler and the coating cannot be performed. Therefore, in the present invention, it is preferable to select a UV curable resin having a viscosity as low as possible.

A radical initiator is used for these. Examples of the radical initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-diethoxyacetophenone and 4'-phenoxy-2,2-dichloroacetophenone. Examples thereof include acetophenone-based compounds, propiophenone-based compounds such as 2-hydroxy-2-methylpropiophenone, anthraquinone-based compounds such as 2-chloroanthraquinone, and thioxanthone-based compounds such as 2,4-diethylthioxanthone. The amount to be added at this time is 0.1 to 10 parts by weight of the resin content. It is preferably 1 to 8 parts by weight. The radical initiator may be used alone or in combination of two or more.

In the present invention, the filler is the resin 10
1 to 80 parts by weight is added to 0 parts by weight, and preferably 5 to 50 parts by weight. Considering storage stability, it is desirable to stir uniformly with a disperser or the like. When excessively kneaded with a roll mill such as three rolls, the filler forming the secondary particles from fine primary particles such as synthetic silica is dispersed into the primary particles, and the secondary particles already described. As a result, it will not be able to exhibit its original characteristics. Also, in the case of organic fillers such as protein and cellulose that use natural products, they are naturally soft, so if they are excessively kneaded, the shape will collapse,
This is because the water absorbency and oil absorbency may decrease.

The method for forming the layer exposed on the surface (outermost layer or outermost surface layer) is a bar coating method, a blade coating method, an air knife coating method, a roll coating method,
Although there is a screen printing method, the writability can be further improved by making the surface uneven. Therefore, it is particularly desirable to apply the screen printing method. In the present invention, when forming this resin layer, a solvent may be used in order to improve the coatability of the UV curable resin, as long as a drying step is not substantially required. In addition,
The film thickness is designed to be about 1 to 100 μm, but considering the influence on the warp of the disk, about 1 to 20 μm is desirable. If there is at least one protective layer on the reflective layer, the protective layer thereon may be provided on the entire surface of the disc or partially.

The applied resin layer is cured by UV light, but when it is cured by applying UV light, it is 150 to 2000 m.
Energy of J / cm ² is applied. Preferably from 250
Apply 1000 mJ / cm ² . At this time, the coating film hardens within a few seconds. If a thermosetting or heat-drying resin that uses a solvent is used, the heating time is at least a few minutes. Further, in consideration of the fact that when the media are stacked or tilted, problems such as non-uniformity of the coating film, corrosion of the substrate by the solvent, adhesion of the resin to other parts, and uneven drying may occur. The UV curable resin used is most desirable.

In the UV-curable resin, the monomers are polymerized and post-crosslinked, and therefore, unlike the method of dissolving the polymer in a solvent and coating and drying, separation of the added hydrophilic polymer in a moisture resistance test environment, It has a great effect that precipitation is small. That is, in practice, since the optical recording medium of the present invention may be used in a high humidity environment, it is a medium that does not cause stickiness of the surface of the medium due to separation and precipitation of the hydrophilic polymer and deterioration of printing characteristics. Is strongly desired. From this point of view, it can be said that the UV curable resin is suitable.

In the present invention, the UV lamp used for curing may be a mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, or the like, but a high-pressure mercury lamp or a metal halide lamp is preferable in view of the generated energy and the price of the lamp. It should be noted that layers may be partially overlapped in addition to the printed portion where characters are written or printed.
For example, a common company name or mark, a medium product name, a software name to be recorded in the medium, etc. may be described in portions other than where different titles, numbers, dates, etc. are written for each medium. In such a case, several layers may be further stacked by screen printing or offset printing. When writing on the protective layer exposed on the surface thus configured, an oil-based pen, water, an aqueous pen containing a water-soluble organic solvent, an oil-based stamp, or an aqueous stamp can be used. Further, an inkjet printer using oil-based or water-based ink, a sublimation printer, or a thermal transfer printer can also be used.

An ink composed of a UV curable resin composition forming a resin for a protective layer exposed on the surface and having a filler as described above and a filler are UV suitable for printing a printable protective layer on the surface. The curable ink can be used not only for an optical recording medium having a recording layer, but also for the surface of another substrate. For example, it can be applied to various surfaces such as exterior surfaces of magneto-optical discs, mini discs, floppy discs, cassette tapes, etc., character entry fields for magnetic cards, optical cards, various plastic films, papers, metals and the like.

[0038]

EXAMPLES Examples of the present invention will be shown below, but the embodiments of the present invention are not limited thereto. Example 1 0.5 g of a phthalocyanine dye was dissolved in 10 ml of n-octane to prepare a coating solution. This solution was spun on a polycarbonate injection-molded substrate (outer diameter 120 mm, thickness 1.2 mm) having a spiral groove with a track pitch of 1.6 μm, a groove width of 0.6 μm and a groove depth of 0.1 μm, and a rotation speed of 150.
A recording layer was formed by spin coating at 0 rpm. Next, gold was formed into a film having a thickness of 60 nm on this recording layer by a sputtering method. Further, on this reflective layer, an ultraviolet curable resin SD-17
After spin coating (manufactured by Dainippon Ink and Chemicals, Inc.),
It was irradiated with ultraviolet rays and cured to form a 3 μm protective layer. 20 parts by weight of bisphenol A epoxy acrylate, 10 parts by weight of dipentaerythritol hexaacrylate, 65 parts by weight of N-vinyl-2-pyrrolidone, radical initiator Darocur 1173 (2-hydroxy-2-methyl-1-phenyl-propane). 10 parts by weight of an organic filler containing a protein as a main component (average particle size of 10 μm) was added to 5 parts by weight of resin (1-one), and the mixture was mixed with a disper. It was printed by screen printing to have a length of 5 cm, a width of 3 cm, and a film thickness of 20 μm. After that, when UV irradiation was performed with an 80 W 2 lamp (which was set to transport the medium at a belt speed of 5 m / min) UV irradiation device, curing was completed in a few seconds. When characters were written on the surface of this print with a commercially available oil-based pen and a water-based pen, it was never repelled. In addition, when characters were printed directly on this resin layer with an inkjet printer, it was possible to print without bleeding. That is, the printing characteristics of this medium are extremely good.

Example 2 After the recording layer and the reflective layer were formed in the same manner as in Example 1, 40 parts by weight of urethane acrylate oligomer, 30 parts by weight of totimethylolpropane triacrylate, and vinylpyrrolidone 2 were used.
Synthetic silica TOKUSIL GU (manufactured by Tokuyama Soda Co., Ltd., primary particle diameter 18-40 μm, secondary particle diameter approximately 20 μm) mixed with 5 parts by weight, (α-hydroxyalkylphenone type) radical initiator Irgacure 1848 parts by weight
20 parts by weight of m) was mixed with 100 parts by weight of the resin and kneaded with a disper. It was printed by screen printing in a donut shape with a radius of 18 mm to 11.9 mm to completely cover the reflective layer and a film thickness of 30 μm. 80W 2 lamps (set to transport media at belt speed 5m / min)
It was cured with a UV curing device. When characters were written on the surface of this print with a commercially available oil-based pen and a water-based pen, it was never repelled. In addition, when characters were printed directly on this resin layer with an inkjet printer, it was possible to print without bleeding. That is, the printing characteristics of this medium are extremely good.

Example 3 After the recording layer and the reflective layer were formed as in Example 1, a UV curable resin SD-17 (manufactured by Dainippon Ink and Chemicals, Inc.) was spin-coated on the reflective layer, and then ultraviolet rays were applied. Was irradiated and cured to form a 3 μm protective layer. Urethane acrylate oligomer 10 parts by weight, hydroxyethyl acrylate 60 parts by weight, 1,4 butanediol diacrylate 25
Parts by weight, 5 parts by weight of radical initiator Darocure 1173, 5 parts by weight of resin mixed with 5 parts by weight of ground cellulose (average particle size 15 μm) and T of white carbon.
Add 20 parts by weight of OKUSIL GU and mix thoroughly with a disper. 119 mm in diameter by screen printing,
It was printed in a 40 mm concentric donut shape. It was cured with an 80W 2 lamp (set to transport media at belt speed 5m / min) UV irradiation device. When characters were written on the surface of this print with a commercially available oil-based pen and a water-based pen, it was never repelled. In addition, when characters were printed directly on this resin layer with an inkjet printer, it was possible to print without bleeding. That is,
The printing characteristics of this medium are very good.

Example 4 After the recording layer and the reflective layer were formed as in Example 1, an ultraviolet curable resin SD-17 (manufactured by Dainippon Ink and Chemicals, Inc.) was spin-coated on the reflective layer, and then ultraviolet rays were applied. Was irradiated and cured to form a 3 μm protective layer. Polyvinylpyrrolidone-vinyl acetate copolymer (7: 3, 50% ethanol solution, manufactured by Tokyo Kasei Co., Ltd.) 10 parts by weight, acroylmorpholine 80 parts by weight, trimethylolpropane triacrylate 5 parts by weight, radical initiator Darocur 1173.
5 parts by weight of resin mixed with synthetic silica TOK
40 parts by weight of USIL GU was added and mixed well with a disper. It is screen printed with a diameter of 119 mm, 4
It was printed in a 0 mm concentric donut shape. It was cured with an 80W 2 lamp (set to transport media at belt speed 5m / min) UV irradiation device. When characters were written on the surface of this print with a commercially available oil-based pen and a water-based pen, it was never repelled. In addition, when characters were printed directly on this resin layer with an inkjet printer, it was possible to print without bleeding. That is, the printing characteristics of this medium are extremely good.

Example 5 After the recording layer and the reflective layer were formed as in Example 1, the ultraviolet curable resin SD-17 (manufactured by Dainippon Ink and Chemicals, Inc.) was spin-coated on the reflective layer, and then the ultraviolet ray was applied. Was irradiated and cured to form a 3 μm protective layer. Polyacrylamide 1
5 parts by weight, 62 parts by weight of hydroxy acrylate, 10 parts by weight of neopentyl glycol diacrylate, 5 parts by weight of dipentaerythritol hexaacrylate, radical initiator Darocur 4265 (Darocur 1173 and 2,
5 parts by weight of a 1: 1 mixture of 4,6-trimethylbenzoyldiphenyl-phosphine oxide). To the resin, 15 parts by weight of protein filler, 5 parts by weight of synthetic silica TOKUSILGU, and 3 parts by weight of Aerosil for viscosity adjustment were added and thoroughly mixed with a disper. It is screen-printed with a diameter of 119 mm, 40
It was printed in a concentric donut shape of mm. It it 8
It was cured with a 0 W 2 lamp (set to transport the medium at a belt speed of 5 m / min) UV irradiation device. When characters were written on the surface of this print with a commercially available oil-based pen and a water-based pen, it was never repelled. In addition, when characters were printed directly on this resin layer with an inkjet printer, it was possible to print without bleeding. That is, the printing characteristics of this medium are extremely good.

Comparative Example 1 After the recording layer and the reflective layer were formed as in Example 1, a UV curable resin SD-17 containing no filler was spin-coated and then cured with UV light. After that, when characters were written directly on the surface of the ultraviolet curable resin layer with a commercially available oil-based pen and a water-based pen, some of the oil-based pens repelled the ink, and the characters became unreadable. I couldn't write an aqueous pen.

Comparative Example 2 After the recording layer and the reflective layer were formed as in Example 1, the UV curable resin SD-17 was similarly spin coated and then cured with UV light. Commercially available UV-curable ink for screen printing for CDs containing a pigment on it (Dainippon Ink and Chemicals, Inc.)
5 cm in length, 3 cm in width, and 20 μm in film thickness.
It was cured with an 80 W 2 lamp (set to transport media at belt speed 5 m / min) UV irradiation device. When characters were written on this printing surface with a commercially available oil-based pen and a water-based pen, the oil-based pen had some ink repelled. I couldn't write an aqueous pen.

Comparative Example 3 After the recording layer and the reflective layer were formed as in Example 1, the UV curable resin SD-17 was similarly spin coated and then cured with UV light. On top of that, 10 parts by weight of urethane acrylate oligomer, 60 parts by weight of hydroxyethyl acrylate, 1, 4
Resin 100 in which 25 parts by weight of butanediol diacrylate and 5 parts by weight of radical initiator Darocure 1173 are mixed
Mechanically crushed silica (average particle size 5μ)
20 parts by weight of m) was added. It was printed by screen printing into a concentric donut shape with a diameter of 119 mm and 40 mm. Then, it was cured by a UV irradiation device of 80 W2 lamp (set to transport the medium at a belt speed of 5 m / min). I was able to write on the surface of this printing with a commercially available oil-based pen, but when I wrote with a water-based pen or an inkjet printer, the solvent and water did not dry and the repellency was awful.

Comparative Example 4 After the recording layer and the reflective layer were formed as in Example 1, the UV curable resin SD-17 was spin-coated and cured by ultraviolet rays in the same manner, and then 10 parts by weight of polyvinyl alcohol and 10 parts by weight of polyvinyl pyrrolidone were added. Part was sufficiently dissolved in ethanol, and then 5 parts by weight of TOKUSIL GU of synthetic silica was added.
Screen printing it to 119mm and 40mm in diameter
It was printed in the shape of a concentric donut. After that, it had to be dried at 60 ° C. for 1 hour with a blow dryer until it became tack-free. I was able to write on this printing surface with a commercially available oil-based pen, water-based pen, inkjet printer,
When the moisture and heat resistance test was carried out at 80 ° C. and 85% RH for 100 hours, the coating film was partially dissolved by water, and the coating film was not uniform. As described above, the results of Examples and Comparative Examples are summarized in [Table 1]. The moisture and heat resistance test was carried out by leaving the produced optical recording medium in a thermo-hygrostat at a temperature of 80 ° C. and a relative humidity of 85% for 100 hours.

[0047]

[Table 1] 1. Printing test with various pens and inkjet printers Oily 1: Mitsubishi Marker A-5 Oily 2: Pentel felt pen Aqueous 1: Pilot DRAWING PEN Aqueous 2: ZEBRA Highlighter Inkjet printer: Canon bubble jet printer result ○: Ink repels You can write cleanly without any problems. △: A part of the written part is repelled. ×: The character is repelled and the characters cannot be read. Along with that, the ink does not dry 2. Humidity and heat resistance test 80 ° C. 85% RH 100 hours Results ○: Written ink does not flow Δ: Written ink is bleeding and unreadable ×: Part of the coating film melts and deposits

[0048]

As described above, according to the present invention, it is possible to manufacture an optical recording medium in which ink can be written on the surface of a medium with a writing instrument without being repelled or smeared. Further, since the UV curable resin is used, there are advantages that workability is good and takt time is shortened.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an optical recording medium which is a target of the present invention.

[Explanation of symbols]

 1 transparent substrate 2 recording layer 3 metal reflective layer 4 protective layer 5 protective layer

Claims (16)

[Claims] 1. In an optical recording medium comprising a transparent substrate, a recording layer, a metal reflection layer, and one or more protective layers laminated in this order, the protective layer exposed on the surface is water-absorbing and An optical recording medium comprising a UV curable resin containing an organic filler and / or an inorganic filler having an oil absorbing property, the surface of the protective layer being printable. 2. An optical recording medium comprising a transparent substrate, a recording layer, a metal reflective layer, one layer or two or more protective layers laminated in this order, wherein the protective layer exposed on the surface is water absorbing and The optical recording medium according to claim 1, which is made of a UV curable resin containing an organic filler having an oil absorbing property. 3. The protective layer made of a UV curable resin exposed on the surface is a) 1 to 80 parts by weight of a hydrophilic polymer, b) 20 to 98 parts by weight of a hydrophilic monomer, and c) a copolymerizable monomer 0. Optical recording according to claim 1 or 2, which is obtained by UV-curing a kneaded product of a curable composition consisting of ~ 40 parts by weight, and d) 0.1-10 parts by weight of a radical initiator and a filler. Medium. 4. The protective layer made of a UV curable resin exposed on the surface is a) 10 to 70 parts by weight of hydrophilic polymer, b) 50 to 90 parts by weight of hydrophilic monomer, and c) copolymerizable monomer 1. The optical recording medium according to claim 3, which is obtained by UV-curing a kneaded product of a curable composition consisting of ˜20 parts by weight, and d) 1 to 8 parts by weight of a radical initiator and a filler. 5. The light according to claim 1, wherein the organic filler contained in the protective layer made of a UV curable resin exposed on the surface is at least one of lignin, protein and cellulose. recoding media. 6. The inorganic filler contained in the protective layer made of a UV curable resin exposed on the surface is synthetic silica,
Talc, clay, calcium carbonate, calcium silicate,
The optical recording medium according to claim 1, comprising at least one of barium sulfate, mica, diatomaceous earth silica, aluminum hydroxide, alumina, zirconium oxide, and zirconium hydroxide. 7. The UV curable resin is a protective layer made of the UV curable resin exposed on the surface and the UV curable resin 10.
The optical recording medium according to claim 1, wherein the total amount of the organic filler and / or the inorganic filler is 1 to 80 parts by weight with respect to 0 parts by weight. 8. The UV-curable resin layer, which is exposed on the surface, is a UV-curable resin and the UV-curable resin 100.
The optical recording medium according to claim 7, wherein the total amount of the organic filler and / or the inorganic filler is 5 to 50 parts by weight with respect to parts by weight. 9. The protective layer made of a UV curable resin exposed on the surface is formed by screen printing, a bar coating method, a blade coating method, an air knife coating method or a roll coating method. The optical recording medium according to any one of the above. 10. The protective layer made of a UV curable resin exposed on the surface is obtained by forming a protective layer and then irradiating it with UV light to cure it. Optical recording medium. 11. An optical recording medium for printing by depositing and fixing ink on the surface of a protective layer made of a UV curable resin exposed on the surface of the optical recording medium according to claim 1. Description: Surface printing method. 12. The ink according to claim 11, which is aqueous.
Printing method described. 13. The surface of an optical recording medium according to claim 11, wherein the ink is attached to a protective layer exposed on the surface by an ink jet printer, a sublimation printer, or a thermal transfer printer. Printing method. 14. A UV-curable type suitable for forming a printable protective layer comprising a water-absorbent and / or oil-absorbent organic filler and / or inorganic filler and the UV-curable composition according to claim 3 or 4. ink. 15. The UV curable resin according to claim 14, and the total amount of the organic filler and / or the inorganic filler having a water-absorbing property and / or an oil-absorbing property with respect to 100 parts by weight of the UV-curing resin is 1 to 80 parts by weight. UV curable ink suitable for forming a printable protective layer consisting of a part. 16. The UV curable resin according to claim 15, and the total amount of the organic filler and / or the inorganic filler having water absorbability and / or oil absorbency is 5 to 50 parts by weight with respect to 100 parts by weight of the UV curable resin. A UV curable ink suitable for forming a printable protective layer consisting of