JPH07272441A - Optical recording medium - Google Patents

Abstract

PURPOSE:To avoid blurring from occurring in printing, increase a drying speed and improve the fire-resistant properties by a method wherein a recording surface on which writing with ink containing water-soluble dye is possible and smectite is contained in therecording surface. CONSTITUTION:A recording layer 13 whose main component is pigment is provided on a substrate 12 and a reflective layer 14 is stuck tightly to the recording layer 13 and, further, a protective film 15 is provided. A recording surface layer 17 may be provided on the protective film 15 or a recording surface layer 17 may also serve as a protective film 15. The recording surface layer 17 may be made of recording material which is usually employed as the material for an ink-jet printing method and the material may contain smectite. Starch, gelatin, casein, etc., may be employed as the recording material. If the surface layer 17 contains radiation-curing type compound, it is recommended to contain lipophilic smectite. With this constitution, flurring of printing can be avoided, a drying speed can be increased and, further, the fire-resistant properties can be improved.

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 on which a label surface can be written with an ink containing a water-soluble dye.

[0002]

2. Description of the Related Art An optical recording medium, in particular, an optical recording medium such as a recordable compact disc (CD-R), has a surface on the side where a normal label is printed (hereinafter referred to as "recording content"). , On the label side). Therefore, there is one in which the surface of the label side is roughened so that writing can be performed with a pencil, but the writing tends to damage the optical recording layer and cause an increase in errors. For this reason, in such an optical recording medium, it is preferable to perform recording by an inkjet recording method, which enables writing without contact with the surface layer to be recorded.

The ink used in the ink jet recording system usually contains a water-soluble dye such as an acid dye or a direct dye and water as a solvent as the main components, and often contains a small amount of polyhydric alcohol. There is.

Conventionally, as a recording substrate used in an ink jet recording system using such an ink, a component which is hard to volatilize such as a polyhydric alcohol in the ink is absorbed and dispersed in an ink receiving layer to dry and fix the ink. In order to accelerate the process, ordinary paper or special paper for inkjet provided with a porous ink receiving layer is used.

When the substrate is hydrophilic and porous like paper, the substrate alone has an effect as an ink receiving layer.
However, when the substrate is non-porous, it takes a long time to dry and fix due to the components that are hard to volatilize contained in the ink. For this reason, if the printed portion is brought into contact with the ink when it is not dried, the ink may adhere to the printed portion or the printed matter may be damaged. Therefore, conventionally, such a substrate is provided with an ink receiving layer containing porous particles. Examples of the porous material used for such an ink receiving layer include silica, clay,
Inorganic pigment particles such as talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, lithobone, and titanium white are known (JP-A-61-228).
No. 984, Japanese Patent Publication No. 4-1706, etc.).

The optical recording medium is usually a protective film made of an ultraviolet curable resin having a non-porous surface, the surface of which is on the label side side being hydrophobic. Therefore, if an attempt is made to write directly on the label side surface by the ink jet recording method, the ink will be repelled and writing will not be possible.

Therefore, in order to enable writing by the ink jet recording system, an attempt was made to provide an ink receiving layer containing the porous particles on the protective film. However, the drying speed of the ink after printing and the water resistance of printing are poor, and sufficient characteristics as a recording material cannot be obtained.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical recording having a recording surface layer which can be written with an ink containing a water-soluble dye, has a high drying speed of printing, and has high water resistance of printing. To provide the medium.

[0009]

These objects are achieved by the present invention described in (1) to (7) below. (1) An optical recording medium having a recording surface layer writable by an ink containing a water-soluble dye, the recording surface layer containing smectite. (2) The optical recording medium according to (1) above, wherein the smectite content is 1 to 50 wt% of the recording surface layer. (3) The optical recording medium according to the above (1) or (2), wherein the recording surface layer is obtained by curing a coating film containing a radiation curable compound and smectite. (4) The optical recording medium according to any one of (1) to (3), wherein the smectite is a smectite-organic composite. (5) The optical recording medium according to any one of (1) to (4), wherein the recording surface layer is cured by ultraviolet rays. (6) The optical recording medium according to any one of (1) to (5), wherein the recording surface layer has a layer thickness of 1 to 100 μm. (7) The optical recording medium according to any one of (1) to (6), wherein the writing is performed by an inkjet recording method.

[0010]

FUNCTION AND EFFECT The smectite contained in the surface layer to be recorded of the optical recording medium of the present invention is a kind of layered silicate as shown in FIG. 1, and its unit structure is basically Si-O ₄ 4
The 2: 1 structure in which the tetrahedron sheet in which the tetrahedrons share the oxygen apex and spread in a hexagonal mesh shape and the remaining apexes face each other to sandwich the cations to form an octahedron sheet of oxygen is used as a unit layer, This has an overlapping structure. Then, it swells in a solvent, the layered structure is broken, and it exhibits colloidal properties. Therefore, the guest substance has a high adsorption ability, and the existing cations are more likely to adsorb anions such as sulfonic acid groups of the ink dye, which makes the fixing rate of the ink higher than that of conventional porous particles. The retention characteristics are remarkably excellent. Therefore, by including this smectite in the recording surface layer, the drying speed after printing is high, the water resistance of the printing is excellent, and for example, an excellent recording surface layer in which the printing does not change even when exposed to running water is formed. The optical recording medium is realized.

Japanese Unexamined Patent Publication (Kokai) No. 6-60432 discloses an optical information medium (compact disc) in which a hydrophilic resin film is formed on the label surface side to enable printing with an aqueous printing ink. In order to roughen the surface of this hydrophilic resin film, it is disclosed that an organic or inorganic content is dispersed in the hydrophilic resin film, but smectite is not described.

[0012]

Specific Structure The specific structure of the present invention will be described in detail below.

The optical recording medium of the present invention has a writable recording surface layer writable by an ink containing a water-soluble dye,
This recording surface layer contains smectite.

FIG. 2 shows an example of the optical recording medium of the present invention.

In an example of the optical recording medium 1 which can be used in the present invention shown in FIG. 2, a recording layer 13 containing a dye as a main component is provided on a substrate 12, and the reflective layer 1 is adhered to the recording layer 13 in close contact therewith.
4 and further has a protective film 15. The recording surface layer 17 used in the present invention may be provided on the protective film 15, or an adhesive layer (not shown) may be provided on the protective film 15 to have the adhesive layer. The recording surface layer 17 may also serve as the protective film 15.

As the recording surface layer 17 of the present invention, any conventionally known recording material which is usually used in the ink jet recording system can be used. It suffices that these contain smectite.

As such a recording material, starch,
Water-soluble polymer layers such as gelatin, casein, gum arabic, sodium alginate, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, and sodium polyacrylate; synthetic resin latex such as synthetic rubber latex; organic solvent such as polyvinyl butyral and polyvinyl chloride. Soluble resin layers and polymers having cationic ions such as polyvinyl alcohol having a quaternary ammonium salt group, polyacrylic acid ester, and polyacrylic acid amide (Japanese Patent Application Laid-Open No. 61-228984).
And the like) and hydrophilic recording surface layers such as polyethylene glycol dicarboxylic acid (Japanese Patent Publication No. 4-1706). Such a hydrophilic recording surface layer 1
In the case of 7, the smectite used is preferably a hydrophilic smectite described later.

When such a recording surface layer 17 is used, in order to improve the adhesion with the protective film 15 obtained by curing the coating film containing the radiation-curable compound, the protective film 15 and the recording surface layer 17 are improved. It is preferable to provide an adhesive layer between and. The adhesive layer may have any excellent adhesiveness to the protective film and the hydrophilic recording surface layer, and may be selected from known adhesive layers.

Further, such a hydrophilic recording surface layer 1
As a method of forming 7 or the adhesive layer, any known method can be used.

However, in such a hydrophilic recording surface layer 17, the recording surface layer 17 itself tends to be inferior in water resistance and water resistance of printing. Therefore, it is preferable that the surface layer 17 to be recorded contains a radiation-curable compound and smectite described later.

When the coating film containing the radiation-curable compound and smectite is cured, the recording surface layer 17 may also serve as the protective film 15, and the recording film on the protective film 15 may be used. The surface layer 17 may be separately provided. Further, an adhesive layer or the like may be provided between the recording surface layer 17 and the protective film 15. However, from the viewpoint of manufacturing cost, it is preferable that the recording surface layer 17 also serves as the recording surface layer 17 or that the recording surface layer 17 is provided on the protective film 15.

When the surface layer 17 to be recorded contains a radiation-curable compound, the smectite to be used is preferably a smectite-organic composite (hereinafter referred to as lipophilic) which is preferably dispersed in the coating film containing the radiation-curable compound. It is preferably described as smectite).

Smectite is a kind of silicate having a layered structure, and there are natural ones and industrially synthesized ones.
In the present invention, either a natural product or a synthetic product may be used, but an industrially synthesized product is preferable in view of the characteristics in a solvent or the absence of impurities.

Synthetic smectites are commercially available as those industrially synthesized. As commercially available synthetic smectites, there are a hydrophilic type that swells in water and collapses the layered structure to become colloidal and exhibits viscosity, and a lipophilic type that exhibits colloidal properties in an organic solvent and exhibits viscosity. . As a hydrophilic type, there is a hydrophilic smectite commercially available as SWN (manufactured by Corp Chemical).

The lipophilic smectite is obtained by substituting Na ions and the like in the layered structure of hydrophilic smectite with organic ions which can be solvated with a low polar solvent or a high polar solvent. Such an organic ion is not particularly limited, but examples thereof include tetramethylammonium, tetraethylammonium, and the like, such as quaternary ammonium having an alkyl group having about 1 to 10 carbon atoms.

By selecting an organic ion to be substituted, it is well dispersed in various organic solvents to exhibit colloidal properties and viscosity, and further has excellent properties of intercalating a guest substance such as ink or its solvent. It has. Such lipophilic smectites include SAN, STN,
Some are commercially available as SEN and SPN (both manufactured by Corp Chemical).

As described above, such smectites have a property of increasing the viscosity of the solution by swelling in a solvent and exhibiting a colloidal property in both hydrophilicity and lipophilicity as described above. For this reason,
By including smectite, the viscosity of the coating liquid for the surface layer 17 to be recorded can be adjusted, and the range of selection of the coating method is greatly expanded.

Specifically, even a coating liquid having a composition that cannot be applied because the viscosity is too low can be applied by a general coating method such as a screen printing method, a gravure roll method, and a bar coater method. .

The content of smectite is preferably 1 to 50% by weight, more preferably 3 to 45% by weight of the surface layer 17 to be recorded.
wt%, particularly preferably 5 to 40 wt%. By containing smectite in such a range, it is possible to write with an ink containing a water-soluble dye, the drying speed of printing is fast, and the ink dye used is intercalated in smectite and firmly bonds. Thus, the recording surface layer 17 having higher printing water resistance is obtained.

If the content is too large, the surface layer to be recorded tends to swell and become brittle, and the durability tends to decrease. Furthermore, the viscosity of the coating film becomes too high, which makes uniform coating difficult. On the other hand, if the amount is too small, it becomes difficult to write with the ink containing the water-soluble dye, the drying speed of printing is lowered, and the water resistance of printing is also deteriorated.

The specific surface area of the smectite used is preferably 200 to 1000 m ² / g, more preferably 500 to 1
000 m ² / g, particularly preferably 710 to 800 m ² / g. In such a range, an excellent effect as an ink receiving layer can be obtained. If the specific surface area is too small, an excellent effect as an ink receiving layer cannot be obtained. Further, if it is too large, there is no particular problem, but normally, the amount exceeding the above range cannot be obtained.

When the surface of the recording surface layer 17 is observed with an optical microscope, the average major axis of smectite observed in an irregular shape is preferably 0.1 to 100 μm, more preferably 0.5 to 50 μm. , Particularly preferably 1 to 4
It is 5 μm. If the average major axis is too large, the film becomes brittle or the film surface becomes rough. If it is too small, the permeation rate of the solvent tends to decrease, and the drying rate of the print tends to decrease.

Recording surface layer 17 of the optical recording medium 1 of the present invention.
In addition, as a porous material other than smectite, porous particles that have been conventionally used, for example, silica, clay,
Inorganic pigment particles such as talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, lithobone, and titanium white may be contained.

Examples of the radiation-curable compound include acrylic double bonds such as acrylic acid, methacrylic acid, or their ester compounds having an unsaturated double bond which is sensitive to ionization energy and exhibits radical polymerizability, diallyl. Mention is made of monomers, oligomers, polymers, etc. containing or introducing into the molecule a group capable of being crosslinked or polymerized by radiation such as an allyl double bond such as phthalate, an unsaturated double bond such as maleic acid or a maleic acid derivative. You can These may be used alone or in combination of two or more.

The radiation curable monomer has a molecular weight of 2
A compound of less than 000 has a molecular weight of 20 as an oligomer.
Those of 00 to 10,000 are preferable. These include styrene, ethyl acrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol methacrylate, 1,6-hexane glycol diacrylate, 1,6-hexane glycol dimethacrylate, etc., but particularly preferred ones As, pentaerythritol tetraacrylate (methacrylate), pentaerythritol acrylate (methacrylate), trimethylolpropane triacrylate (methacrylate), trimethylolpropane diacrylate (methacrylate), acrylic modified urethane elastomer,
Alternatively, those into which a functional group such as COOH has been introduced, acrylates (methacrylates) of phenol ethylene oxide adducts, acryl groups (methacryl groups) or ε-in the pentaerythritol condensed ring shown in Japanese Patent Application No. 62-072888. Examples thereof include compounds having a caprolactone-acrylic group, and acrylic group-containing monomers and / or oligomers such as special acrylates disclosed in Japanese Patent Application No. 62-072888. Besides this,
Examples of radiation-curable oligomers include oligoester acrylates, acrylic modified urethane elastomers, and those into which a functional group such as COOH is introduced.

The oligoester acrylate is an oligoester compound having a plurality of acrylate groups or methacrylate groups. The preferred oligosteracrylates include those having a molecular weight of 1,000 to 10,000, preferably 2,000 to 7,000, and a polymerization degree of 2 to 10, preferably 3 to 5. Further, among these, 2 to 6 acrylate groups or methacrylate groups are used.
Polyfunctional oligoester acrylates having one, preferably 3 to 6, are preferred.

As the polyfunctional oligoester acrylate, Aronix M-7100, M-8030, M-80
60, M-8100, M-9050, M-6100, M
-6200, M-6250, M-6300, M-640
0, M-6500 and the like (manufactured by Toagosei Kagaku Co., Ltd.) can be used, and these are represented by the following chemical formulas 1 and 2.

[0038]

[Chemical 1]

[0039]

[Chemical 2]

A: acrylate group or methacrylate group, X: polyhydric alcohol (eg, glycerol) residue, Y: polybasic acid (eg, citric acid) residue, M:
Dihydric alcohol (eg, ethylene glycol, diethylene glycol, 1,6-hexane glycol, bisphenol A, etc.) residue, N: dibasic acid (eg, terephthalic acid, isophthalic acid, adipic acid, succinic acid, etc.) residue,
n: 1-10, preferably 2-5. Of these,
Those represented by Chemical formula 1 are preferable.

As the oligoester acrylate, monofunctional ones shown in Chemical formulas 3 to 6 can also be used. Chemical formula 3 is Aronix M-5300, chemical formula 4 is Aronix M-5400, and chemical formula 5 is Aronix M-5.
It is possible to use a commercially available product of Aronix M-5700 of Chemical Formula 6 and Chemical Formula 6.

[0042]

[Chemical 3]

[0043]

[Chemical 4]

[0044]

[Chemical 5]

[0045]

[Chemical 6]

In addition to the above-mentioned compounds, or in place of this, a radiation-curable compound obtained by radiation-sensitively modifying a thermoplastic resin may be used. Specific examples of such radiation curable resins include acrylic double bonds having an unsaturated double bond exhibiting radical polymerizability, acrylic double bonds such as methacrylic acid, or ester compounds thereof, and diallyl phthalate. It is a resin in which a group such as an allyl double bond, an unsaturated bond such as maleic acid or a maleic acid derivative, which is crosslinked or polymerized by irradiation with radiation is contained or introduced in the molecule of the thermoplastic resin. Examples of thermoplastic resins that can be modified into radiation-curable resins include vinyl chloride copolymers, saturated polyester resins, polyvinyl alcohol resins, epoxy resins, phenoxy resins, fibrin derivatives and the like. Other resins that can be used for radiation-sensitive modification include polyfunctional polyester resins, polyetherester resins, polyvinylpyrrolidone resins and derivatives (P
(VP olefin copolymer), polyamide resin, polyimide resin, phenol resin, spiro acetal resin, acrylic resin containing at least one of acrylic ester and methacrylic ester having a hydroxyl group as a polymerization component are also effective.

The radiation applied to cure the coating film containing these radiation-curable compounds is ultraviolet light,
An electron beam or the like can be used, but it is preferable to use ultraviolet rays.

When ultraviolet rays are used, it is preferable that the radiation-curable compound contains a photopolymerization initiator.

The photopolymerization initiator is not particularly limited,
Benzoic acid esters, benzophenone derivatives, benzoin derivatives, thioxanthone derivatives, acetophenone derivatives, propiophenone derivatives and benzyl can be used.

Specifically, methyl-orthobenzoylbenzoate, benzophenone, 4,4-bisdiethylaminobenzophenone, dibenzosuberone, benzoylalkyl ether (an alkyl group which may contain R = C ₁ -C ₈ branch), 1-phenyl-1,2-propanedione-2- (ο-ethoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2- (ο-benzoyl) oxime, 2,2-dimethoxy-2-phenyl Acetophenone, 2,2-diethoxyacetophenone, chlorinated acetophenone derivative, 4-isopropyl-2-hydroxy-2-methyl-propiophenone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-2
-Methyl-1-phenylpropan-1-one, benzyl and the like. Among these, a particularly preferable polymerization initiator is 2-hydroxy-2-methyl-1-
Phenylpropan-1-one, 2,2-dimethoxy-2
-Phenylacetophenone, methyl-orthobenzoylbenzoate and the like. Among these particularly preferable polymerization initiators, 2-hydroxy-2-methyl-1-phenylpropan-1-one is Darocur 1173 (manufactured by Merck & Co., Inc.), and 2,2-dimethoxy-2-phenylacetophenone is Irgacure. 651 (manufactured by Nippon Ciba-Geigy Co., Ltd.).

The content of the polymerization initiator in the recording surface layer is
In the surface layer to be recorded excluding the above-mentioned porous particles excluding smectite and smectite optionally added, it is preferably 8 wt% or less, more preferably 0.2 to 5 wt%, and particularly preferably 0.5 to 3 wt%. is there. When the content is less than the above range, the action as a polymerization initiator cannot be sufficiently obtained,
If it is too much, coloring, weathering yellowing, corrosion, etc. occur.

Further, the recording surface layer 17 of the present invention has 2
-Hydroxyethyl methacrylate, acrylamide,
N, N-dimethylaminoethyl acrylate, N, N-
A hydrophilic nonionic monomer such as dimethylaminopropylacrylamide, acryloylmorpholine, N-vinylpyrrolidone and polyethylene glycol monomethacrylate shown in the following chemical formula 7 may be copolymerized.

[0053]

[Chemical 7]

As a composition containing a radiation-curable compound for forming each protective film, a composition containing an epoxy resin and a photocationic polymerization catalyst is also preferably used.

The epoxy resin is preferably an alicyclic epoxy resin, and particularly preferably one having two or more epoxy groups in the molecule. As alicyclic epoxy resin,
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis- (3,4
-Epoxycyclohexylmethyl) adipate, bis-
(3,4-epoxycyclohexyl) adipate, 2-
(3,4-epoxycyclohexyl-5,5-spiro-
One or more of 3,4-epoxy) cyclohexane-meta-dioxane, bis (2,3-epoxycyclopentyl) ether, vinylcyclohexene dioxide and the like are preferable. The epoxy equivalent of the alicyclic epoxy resin is not particularly limited, but 60 to 3 because good curability can be obtained.
00, particularly preferably 100 to 200.

The photocationic polymerization catalyst may be any known catalyst and is not particularly limited. For example, a complex of one or more metal fluoroborate and boron trifluoride,
Bis (perfluoroalkylsulfonyl) methane metal salt, aryldiazonium compound, aromatic onium salt of 6A group element, aromatic onium salt of 5A group element, 3A group
Dicarbonyl chelate of Group 5A element, thiopyrylium salt, MF ₆ anion (where M is P, As or S
Group 6A elements having b), triarylsulfonium complex salts, aromatic iodonium complex salts, aromatic sulfonium complex salts and the like can be used, and in particular, polyarylsulfonium complex salts, aromatic sulfonium salts or iodonium salts of halogen-containing complex ions, 3A It is preferable to use one or more aromatic onium salts of Group 5A group elements and Group 6A elements.

A photocationic polymerization catalyst containing an organometallic compound and a photodegradable organosilicon compound can also be used. As the organometallic compound, Ti,
V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al
, Zr and the like, a complex compound in which an alkoxy group, a phenoxy group, a β-diketonato group or the like is bonded to a metal atom is preferable. Of these, organoaluminum compounds are particularly preferable, and specifically, trismethoxyaluminum, trispropionatoaluminum, tristrifluoroacetylaluminum, and trisethylacetoacetonatoaluminum are preferable.

The photodegradable organic silicon compound produces silanol upon irradiation with light such as ultraviolet rays,
A silicon compound having a peroxysilano group, an o-nitrobenzyl group, an α-ketosilyl group or the like is preferable.

The content of the photocationic polymerization catalyst in the composition is 0.05 to 0.
It is preferably 7 parts by weight, particularly 0.1 to 0.5 parts by weight.

Among these, it is preferable that a radiation-curable compound having an acrylic group is used and a coating film containing a photopolymerization sensitizer or an initiator is radiation-cured, especially ultraviolet-cured.

A preferable method for forming the recording surface layer 17 used in the optical recording medium 1 of the present invention containing a radiation-curable compound and smectite is to prepare a coating solution containing the radiation-curable compound and smectite. It may be applied on the reflective layer 14 or the protective film 15 by a known coating method, and may be cured by irradiating it with radiation, preferably ultraviolet rays, using a conventional radiation source such as a mercury lamp by various known methods.

As a coating method, any of commonly used methods such as spin coating method, spray coating method, dipping method, gravure roll method, knife coater method, reverse roll method, screen printing method and bar coater method can be used. it can. In particular, containing smectite,
When a coating liquid having an appropriately adjusted viscosity is used, it can be coated satisfactorily using a screen printing method, a gravure roll method, a bar coater method or the like.

The recording surface layer 17 thus provided has a layer thickness of preferably 1 to 100 μm, more preferably 5 μm.
-80 μm, particularly preferably 10-50 μm. However, when the recording surface layer 17 also serves as the protective film 15, the thickness is preferably 1 to 100 μm, more preferably 10 to 100 μm, and particularly preferably 30 to 80 μm. With such a layer thickness, the effect of the recording surface layer 17 of the optical recording medium of the present invention can be obtained, the drying speed of printing is extremely fast, and the water resistance of printing is high. If the layer thickness is more than the above range, the disc may be distorted due to shrinkage during curing, and if it is too thin, the effects of the present invention such as the drying speed of printing and the water resistance of printing may not be sufficiently obtained.

The substrate 12 has recording light and reproducing light (wavelength 6).
What is formed of a resin or glass that is substantially transparent (preferably a transmittance of 88% or more) to a semiconductor laser light having a wavelength of about 00 to 900 nm, particularly a wavelength of about 770 to 900 nm, particularly 780 nm may be used. This enables recording and reproduction from the back side of the substrate.

As the material for the substrate, it is preferable to use a resin, and various thermoplastic resins such as polycarbonate resin, acrylic resin, amorphous polyolefin, TPX and the like are preferable. The substrate 12 may be manufactured by a known method such as injection molding. At that time, it is preferable to form a predetermined pattern such as the groove 21 on the surface of the substrate for tracking or addressing. After the substrate 12 is manufactured, a resin layer having a predetermined pattern such as a groove may be formed by the 2P method or the like.

The recording layer 13 may contain only one type of dye, or may have a structure in which two or more types of dyes are compatible with each other.

The light absorbing dye used in the recording layer 13 has an absorption maximum of 600 to 900 nm, preferably 600 to 900 nm.
800 nm, more preferably 650 to 750 nm,
Other than that, there is no particular limitation, and for example, one or more of cyanine-based, phthalocyanine-based, naphthalocyanine-based, anthraquinone-based, azo-based, triphenylmethane-based, pyrylium or thiapyrylium salt-based, squarylium-based, croconium-based, metal complex dye-based, etc. Two or more kinds may be appropriately selected according to the purpose.

A quencher may be mixed with the light absorbing dye. Further, an ionic combination of a dye cation and a quencher anion may be used as the light absorbing dye.

As the quencher, acetylacetonate type, bisdithiol type such as bisdithio-α-diketone type and bisphenyldithiol type, thiocatechol type, salicylaldehyde oxime type and thiobisphenolate type metal complex are preferable. . Further, amine compounds having a nitrogen radical cation and amine quenchers such as hindered amines are also suitable.

The dye constituting the conjugate is preferably a cyanine dye having an indolenine ring, and the quencher is preferably a metal complex dye such as bisphenyldithiol metal complex.

The recording layer 13 is formed by a spin coating method in which a coating solution containing a dye and an organic solvent is used and the coating solution is spread and coated on a rotating substrate.

The organic solvent used for the coating liquid for recording formation may be appropriately selected from alcohols, ketones, esters, ethers, aromatics, alkyl halides and the like according to the dye used. However, an organic solvent having two or more functional groups in one molecule is suitable. After spin coating, the coating film is dried if necessary.

The thickness of the recording layer 13 thus formed is appropriately set according to the desired reflectance and the like, but is usually about 1000 to 3000 A.

On the recording layer 13, the reflective layer 1 is directly adhered to the recording layer 13.
4 are laid. A high reflectance material is used for the reflective layer 14. Such materials include Au, Cu, Ag, Al
And alloys containing these are preferable, but the reflective layer 14 preferably contains at least Cu because it is relatively inexpensive and has a high reflectance. In particular, Cu, Ti, and
V, Ta, Cr, Mo, W, Mn, Fe, Co, Rh,
A thin film containing one or more elements selected from the group consisting of Ni, Pd, Pt, Ag, Au, Al, N and O is preferably used as the reflective layer.

In this case, the reflective layer 14 is advantageous in that a higher reflectance can be obtained while maintaining a sufficiently high corrosion resistance.
Is Cu, Ti, V, Ta, Cr, Mo, W, Mn,
A thin film containing at least one element of Fe, Co, Rh, Ni, Pd, Pt, Ag, Au and Al, particularly Cu
And a thin film containing Rh, Ni, Pd, Pt, one or more elements of Ag, Au and Al.

To form the reflective layer 14, various vapor phase film forming methods such as sputtering and vapor deposition may be used.

The thickness of the reflective layer 14 is preferably 500 A or more. Although there is no particular upper limit on the thickness, it is preferably about 1700 A or less in consideration of cost, production work time and the like.

A protective film 15 is provided on the reflective layer 14. However, as described above, when the recording surface layer 17 also serves as the protective film 15, the recording surface layer 17 may be provided on the reflective layer 14.

When the protective film 15 is provided separately from the recording surface layer 17, the protective film 15 is the recording surface layer 17 described above.
Any of radiation curable compounds and photopolymerization initiators that can be preferably used in the above can be used. At this time, the radiation curable compound used for the recording surface layer 17 and the radiation curable compound used for the protective film 15 may be the same or different. The method of forming the protective film 15, the method of curing the same, and the like may be the same as those of the recording surface layer 17.

When the protective film 15 is provided separately from the surface layer 17 to be recorded, the thickness of the protective film 15 is preferably 1-100.
μm, more preferably 10 to 50 μm. If the film thickness is less than the above range, the effect as a protective film cannot be sufficiently obtained, and an error in the recording signal is likely to occur. If the resin film is too thick, warpage of the recording medium and cracks in the protective film are likely to occur due to the shrinkage that accompanies curing of the resin film.

Further, the protective film 15 and the recording surface layer 17 provided on the optical recording medium 1 of the present invention are further provided with a photopolymerization accelerator such as triethanolamine or 2- (dimethylamino) ethylbenzoate and a chain. A transfer agent, a radical polymerization inhibitor such as phenothiazine, and a stabilizer such as a chelating agent such as N-nitrosophenylhydroxylamine aluminum salt may be added.

When writing is performed on the optical recording medium having the recording surface layer 17 thus provided, the writing may be performed with an ordinary pen or the like using the ink containing the water-soluble dye.
It is preferable to use an ink jet recording type writing device because there is a risk of increasing errors.

The ink used is not particularly limited as long as it is an ink containing a water-soluble dye, and any ink used in a writing device of an ink jet recording system can be used.

[0084]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 Protective film composition Polyfunctional oligoester acrylate 97 parts by weight (Aronix M-8100: manufactured by Toagosei Co., Ltd.) 2-Hydroxy-2-methyl-1-phenylpropan-1-one 3 parts by weight (Darocur 1173: Merck) (Made by the company)

A recordable compact disc (CD-CD) having a protective film 15 of an ultraviolet curable resin, which is obtained by coating the coating composition having the above protective film composition on the reflective layer 14 and then curing it by irradiating it with ultraviolet rays by an ultraviolet irradiation device. R) is used to form a coating film on this protective film by a screen printing method using a coating liquid having the following recording surface layer composition. UVM manufactured by Ushio Inc.
UV rays of 160 w / cm were irradiated from a distance of 230 mm by a -602 type UV irradiation device to cure. The recording surface layer had a layer thickness of 20 μm, and the average long diameter of smectite observed from the surface was 10 μm.

Recording surface layer Polyfunctional oligoester acrylate 70 parts by weight (Aronix M-8100: manufactured by Toagosei Kagaku) 2-hydroxy-2-methyl-1-phenylpropan-1-one 5 parts by weight (Darocur 1173: Smectite (lipophilicity: quaternary ammonium substitution type) 25 parts by weight (SAN: Corp Chemical Co., Ltd .: SBET: 710-760 m ² / g)

The recording surface layer of the obtained optical recording medium was evaluated according to the following methods. The obtained results are summarized in Table 1. The printing for evaluation was performed by an inkjet recording method using an ink having the following composition.

Ink composition C. I. Direct Black 5 parts by weight Diethylene glycol 30 parts by weight Water 65 parts by weight

The recording surface layer was evaluated by (1) ink repellency, (2) print drying time, and (3) print water resistance.

The evaluation method was according to the following method.

(1) Ink repelling Printing was performed and the presence or absence of ink repelling was evaluated. The ink that was used without being repelled and was printed normally was marked with ◯, and the ink that was repelled and could not be printed normally was marked with x. In addition, to repel ink to the extent that normal printing is not possible,
This is a case where the contact angle between the recording surface and the ink at 25 ° C. is 60 ° or more.

(2) Drying time of printing After printing was performed, the time until the ink did not adhere to the finger when the printing surface was touched with the finger was defined as the drying time, and was displayed according to the following criteria. When the drying time is 30 seconds or less ◎,
When the drying time was over 30 seconds and 1 minute or less, the result was ◯, when the drying time was over 1 minute, it was Δ, and when the drying time was 24 hours or more, the result was x.

(3) Water resistance of printing When printing was carried out, and after the printing was dried, the surface layer to be recorded was placed in running water for 1 minute, and when no printing bleeding was visually observed, the printing bleeding was slight. If it is recognized, ○, if there is obvious printing bleeding, △,
The case where the printing disappeared was marked with x.

Example 2 A recording surface layer was formed in the same manner as in Example 1 except that the type of smectite in Example 1 was changed from SAN to STN (lipophilicity: quaternary ammonium substitution type: manufactured by Corp Chemical). The provided optical recording medium was obtained. The recording surface layer of the obtained optical recording medium was evaluated in the same manner as in Example 1. The recording surface layer had a layer thickness of 30 μm, and the smectite contained therein had an average major axis of 5 μm when observed from the surface.
The obtained results are summarized in Table 1.

Example 3 An optical recording medium provided with a recording surface layer was obtained in the same manner as in Example 1 except that the coating liquid having the following recording surface layer composition was used. The recording surface layer of the obtained optical recording medium was evaluated in the same manner as in Example 1. The thickness of the recording surface layer is 5
The average long diameter of the smectite contained therein was 0 μm and was 40 μm when observed from the surface. The results obtained are shown in Table 1.
Are shown together.

Recording surface layer Polyfunctional oligoester acrylate 35 parts by weight (Aronix M-8100: manufactured by Toagosei Kagaku) 2-hydroxy-2-methyl-1-phenylpropan-1-one 5 parts by weight (Darocur 1173: Merck Ltd.) Polyethylene glycol monomethacrylate 35 parts by weight (Structure is shown in Chemical Formula 8 below: Bremmer PE-350: NOF Corporation) Smectite (lipophilicity: quaternary ammonium substitution type) 25 parts by weight (SAN: Corp Chemical Co., Ltd. Made: SBET: 710 ~ 760m ² / g)

[0097]

[Chemical 8]

Example 4 Instead of the coating composition having the protective film composition used in Example 1, the coating composition having the recording surface layer composition used in Example 1 was coated on the reflective layer 14 and then irradiated with ultraviolet rays. The apparatus was irradiated with ultraviolet rays to be cured to obtain an optical recording medium 1 having a layer which also serves as the protective film 15 and the recording surface layer 17. Obtained optical recording medium 1
The recording surface layer 17 (which also serves as the protective film 15) of
The same evaluation as in Example 1 was performed. The recording surface layer 17 had a layer thickness of 40 μm, and the average long diameter of the smectite contained therein was 45 μm when observed from the surface. The obtained results are summarized in Table 1.

Example 5 An optical recording medium 1 was obtained in the same manner as in Example 1 except that a coating film was applied by a screen printing method using a coating liquid having the following recording surface layer composition. The recording surface layer 17 of the obtained optical recording medium 1 was evaluated in the same manner as in Example 1. The recording surface layer 17 had a layer thickness of 25 μm, and the average major axis of the smectite contained therein was 30 μm when observed from the surface. The obtained results are summarized in Table 1.

Recording surface layer Polyfunctional oligoester acrylate 80 parts by weight (Aronix M-8100: manufactured by Toagosei Kagaku) 2-hydroxy-2-methyl-1-phenylpropan-1-one 5 parts by weight (Darocur 1173: Merck) Smectite (lipophilicity: quaternary ammonium substitution type) 15 parts by weight (SAN: Corp Chemical: SBET: 710 to 760 m ² / g)

Example 6 An optical recording medium provided with a recording surface layer was obtained in the same manner as in Example 1 except that the coating liquid having the following recording surface layer composition was used. The recording surface layer of the obtained optical recording medium was evaluated in the same manner as in Example 1. The thickness of the recording surface layer is 5
The average long diameter of the smectite contained therein was 0 μm, and when observed from the surface, it was 10 μm. The results obtained are shown in Table 1.
Are shown together.

Recording surface layer Monofunctional oligoester acrylate 40 parts by weight (Aronix M-5600: manufactured by Toagosei Kagaku) Polyfunctional oligoester acrylate 35 parts by weight (Aronix M-8100: manufactured by Toagosei) 2-hydroxy -2-Methyl-1-phenylpropan-1-one 5 parts by weight (Darocur 1173: manufactured by Merck) Smectite (lipophilicity: quaternary ammonium substitution type) 20 parts by weight (SAN: manufactured by Corp Chemical: SBET: 710) ~ 760m ² / g)

Comparative Example 1 Optical recording in which a recording surface layer 17 was provided in the same manner as in Example 1 except that silica (Aerosil: manufactured by Aerosil: average particle size 16 μm) was used instead of the smectite of Example 1. Medium 1 was obtained. Recording surface layer 1 of the obtained optical recording medium 1
For 7, the same evaluation as in Example 1 was performed. The recording surface layer 17 had a layer thickness of 30 μm. The obtained results are summarized in Table 1.

Comparative Example 2 An optical recording medium 1 provided with a recording surface layer 17 was obtained in the same manner as in Example 1 except that silica gel (average particle size 20 μm) was used instead of the smectite of Example 1. The recording surface layer 17 of the obtained optical recording medium 1 was evaluated in the same manner as in Example 1. The recording surface layer 17 has a layer thickness of 40 μm.
It was m. The obtained results are summarized in Table 1.

Comparative Example 3 Recording was carried out in the same manner as in Example 1 except that smectite was removed from the composition of the recording surface layer of Example 1 and 95 parts by weight of polyfunctional oligoester acrylate (Aronix M-8100) was used. The optical recording medium 1 provided with the surface layer 17 was obtained. The recording surface layer 17 of the obtained optical recording medium 1 was evaluated in the same manner as in Example 1. Recording surface layer 17
Had a layer thickness of 35 μm.

Comparative Example 4 Coating of the recording surface layer composition was carried out in the same manner as in Example 1 except that the type of smectite used in Example 1 was changed to SWA (hydrophilicity: manufactured by Corp Chemical Co., Ltd .: SBET: 200 m ² / g). An attempt was made to prepare a coating liquid, but the smectite used was not dispersed in the coating liquid and the coating liquid could not be prepared.

[0107]

[Table 1]

From Table 1, it can be seen that the optical recording medium having the recording surface layer of the present invention can be written with an ink containing a water-soluble dye, has no bleeding of printing, and has an extremely high drying speed of printing. It can be seen that the water resistance of is even higher. On the other hand, those that have a recording surface layer containing silica (aerosil) or silica gel, which are porous particles that have been used in place of smectite, are poor in the drying speed of printing and the water resistance of printing and do not contain smectite. Those having a recording surface layer repelled the ink and could not be printed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a unit structure of constituent elements of smectite used in the present invention.

FIG. 2 is a partial schematic cross-sectional view showing an example of the optical recording medium of the present invention.

[Explanation of symbols]

 1 unit structure of smectite 2 tetrahedral sheet 3 octahedral sheet 11 optical recording medium 12 substrate 13 recording layer 13 14 reflective layer 15 protective film 17 recording surface layer 21 groove

Claims (7)

[Claims] 1. An optical recording medium having a writable recording surface layer made of an ink containing a water-soluble dye, wherein the recording surface layer contains smectite. 2. The optical recording medium according to claim 1, wherein the content of the smectite is 1 to 50 wt% of the recording surface layer. 3. The optical recording medium according to claim 1, wherein the recording surface layer is a coating film containing a radiation curable compound and smectite cured. 4. The optical recording medium according to claim 1, wherein the smectite is a smectite-organic composite. 5. The optical recording medium according to claim 1, wherein the recording surface layer is cured by ultraviolet rays. 6. The recording surface layer has a layer thickness of 1 to 100.
The optical recording medium according to claim 1, wherein the optical recording medium has a size of μm. 7. The optical recording medium according to claim 1, wherein the writing is performed by an ink jet recording system.