JP4173996B2 - Optical information recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information recording medium capable of optically recording / reproducing information. More specifically, the present invention can record / reproduce electronic information optically and record visible information on a label surface using laser light. The present invention relates to an optical information recording medium that can be printed by various printers.
[0002]
[Prior art]
In recent years, electronic information recording media for recording, storing, and rewriting a large amount of information have become increasingly important as computer peripheral devices. Among them, an optical information recording medium that records and reproduces using laser light is attracting attention as a large-capacity recording medium because it can record, store, and reproduce information at high density. Examples of such optical information recording media include phase change type optical recording media represented by CD-RW, DVD-RW, etc., organic dye-based optical recording media represented by CD-R, DVD-R, and the like. Can be mentioned.
[0003]
The contents of the electronic information recorded on such an optical information recording medium can be confirmed by optical reproduction. On the other hand, displaying the contents of the electronic information as visible information on the medium surface is an information management. It is important. As such a display method, conventionally, for example, a method of attaching a label or the like on which the content of electronic information is recorded to a label surface of a medium (a surface opposite to a surface on which electronic information is recorded), or a thermal printer is used. A method (Patent Document 1) for coloring a reversible thermosensitive coloring layer has been reported. Recently, a method of recording visible information on an organic color-forming dye layer formed on the label side of a medium by laser light (Patent Document 2) has been reported, and these have a mechanical effect on the medium. It is expected as a method for recording visible information.
[0004]
[Patent Document 1]
JP 2001-232942 A
[Patent Document 2]
JP 2000-173096 A
[0005]
[Problems to be solved by the invention]
By the way, the method of applying a label or the like on the label surface of the medium has a balance when rotating the medium because the label is peeled off due to deterioration of the adhesive or the center of gravity of the medium is shifted by applying the label. If it collapses and is significant, recording and reproduction may become difficult. Further, in the method of coloring the reversible thermosensitive coloring layer with a thermal printer, an excessive heating operation may alter the electronic information recorded on the medium, so a heat insulating layer is provided between the recording layer and the thermosensitive coloring layer. It becomes necessary to provide it.
[0006]
Compared with these methods, the method of recording visible information on the organic color-forming dye layer with laser light is more stable when low-power laser light is used without affecting the electronic information recorded on the medium. Therefore, it is considered advantageous in that it is highly possible that visible information can be recorded. The recorded visible information hardly changes even if it is placed in a high humidity environment or a water droplet adheres to it.
[0007]
However, the visible information recorded on the organic chromophoric dye layer by laser light usually depends on the type of organic chromophoric dye used, but usually only monochromatic information is formed, and the label surface design changes. Tend to be poor. For this reason, there is a demand for improving the design of the label surface of the optical information recording medium.
[0008]
The present invention has been made in order to meet the demands that arise when developing an optical information recording medium having a visible information recording layer on the label surface side on which visible information is recorded by such laser light. An object of the present invention is to record visible information without affecting electronic information recorded on a medium by irradiating a low-power laser beam using a laser device for recording / reproducing electronic information. Another object of the present invention is to provide an optical information recording medium having a label surface that can be printed using an ink jet printer.
[0009]
[Means for Solving the Problems]
In order to achieve this object, the optical information recording medium to which the present invention is applied employs a configuration in which an outermost layer formed of a material that can be printed on the label surface is formed. That is, an optical information recording medium to which the present invention is applied is provided on a substrate and directly or via another layer on the substrate, and is visible by light irradiated from the label surface side opposite to the substrate side. It comprises a visible information recording layer on which information is recorded, and a hydrophilic overcoat layer provided directly or via another layer on the visible information recording layer. In the optical information recording medium to which the present invention is applied, the hydrophilic overcoat layer is preferably composed of an ultraviolet curable resin composition containing fine particles having an average particle size of 200 nm or less and a cationic resin. The hydrophilic overcoat layer is preferably laser light transmissive. Furthermore, the lower limit of the thickness of the hydrophilic overcoat layer is preferably 10 μm, and the upper limit is preferably in the range of 100 μm. On the other hand, in the optical information recording medium to which the present invention is applied, the visible information recording layer may be composed of a material whose color developability is changed by light irradiated on the visible information recording layer or a material whose transparency is changed. preferable. An optical information recording medium to which the present invention is applied is provided on a substrate directly or via another layer, and an electronic information recording layer on which electronic information is recorded by light irradiated from the substrate side, and electronic information A reflective layer formed on the opposite side of the recording layer from the substrate side, and the visible information recording layer is preferably formed on the opposite side of the reflective layer from the substrate side.
[0010]
In the optical information recording medium to which the present invention is applied, the “visible information” is information visually read such as characters, symbols, images such as illustrations and photographs, geometric patterns, etc., and “electronic information”. The term “information recorded by a digital signal” refers to information whose contents are read by some playback device. “Laser light transmissive” means that the hydrophilic overcoat layer is light transmissive at the wavelength of the laser light used for recording visible information. Preferably, the absorbance of the hydrophilic overcoat layer at the laser beam wavelength is about 5% or less.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an optical information recording medium to which the present embodiment is applied will be described in detail with reference to the drawings.
FIG. 1 is a diagram for explaining the structure of an optical information recording medium to which the present embodiment is applied. The optical information recording medium 100 shown here includes a substrate 101, an electronic information recording layer 102 formed in order on the substrate 101, and a side opposite to the side on which the laser light 107 of the electronic information recording layer 102 is incident. The reflective layer 103, the protective layer 104, the visible information recording layer 105, and the hydrophilic overcoat layer 106 that forms the outermost layer are sequentially stacked.
[0012]
As shown in FIG. 1, an electronic information recording layer 102 provided in an optical information recording medium 100 is a laser incident through a substrate 101 from an objective lens (not shown) of a laser device for recording / reproducing electronic information. Electronic information is recorded and reproduced by the light 107. On the other hand, the visible information recording layer 105 is irradiated from the label surface side through the hydrophilic overcoat layer 106, for example, when the optical information recording medium 100 is turned over and set in a laser apparatus for recording / reproducing electronic information. Visible information is recorded by the laser beam 108. Part of the laser beam 108 is reflected by the reflective layer 103 provided below the visible information recording layer 105, and the reflected beam 109 is used for focusing for condensing the laser beam 108. Further, the hydrophilic overcoat layer 106 protects the visible information recording layer 105 from physical scratches and the like, and is transparent to the laser light 108 in order to efficiently focus the laser light 108 on the visible information recording layer 105, and The outermost layer surface that can be printed by an inkjet printer or the like is formed.
[0013]
The substrate 101 is basically formed of a material that is transparent to the wavelengths of recording light and reproducing light for the electronic information recording layer 102. As a material for forming the substrate 101, for example, a glass material in addition to a polymer material such as polycarbonate resin, acrylic resin, methacrylic resin, polystyrene resin, vinyl chloride resin, epoxy resin, polyester resin, amorphous polyolefin resin, etc. Inorganic materials are used. In particular, a polycarbonate resin is preferable because it is excellent in terms of high light transmission, low optical anisotropy, and high mechanical strength. Amorphous polyolefin is preferable from the viewpoint of chemical resistance, moisture absorption resistance, optical properties, and the like.
[0014]
For example, the substrate 101 is provided with a recording / reproducing guide groove or pit on the surface in contact with the electronic information recording layer 102 and is formed by a molding method such as injection molding. Such guide grooves or pits are preferably provided at the time of forming the substrate 101, but can also be provided on the substrate 101 using an ultraviolet curable resin, for example. The lower limit of the thickness of the substrate 101 is usually 1.1 mm, preferably 1.15 mm, and the upper limit of the thickness is usually 1.3 mm, preferably 1.25 mm.
[0015]
The electronic information recording layer 102 is formed of a material capable of recording electronic information (information recorded by a reproducing device, such as information recorded by a digital signal) by irradiation with a laser beam 107, and is usually made of an organic substance. Or a recording layer made of an inorganic substance. Note that the electronic information recording layer 102 may be formed directly on the substrate 101, and may be formed between the substrate 101 and the electronic information recording layer 102 via an arbitrary layer as necessary. Also good.
[0016]
When the electronic information recording layer 102 is a recording layer made of an organic material, an organic dye is mainly used. Examples of such organic dyes include macrocyclic azaannulene dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), polymethine dyes (cyanine dyes, merocyanine dyes, squarylium dyes, etc.), anthraquinone dyes, azurenium dyes, azo And dyes containing metal, metal-containing azo dyes, metal-containing indoaniline dyes, and the like. Among these, metal-containing azo dyes, cyanine dyes, and phthalocyanine dyes are preferable. In particular, metal-containing azo dyes are preferable because they are excellent in durability and light resistance.
[0017]
Examples of the method for forming the electronic information recording layer 102 made of an organic material include dry thin film forming methods such as vacuum deposition and sputtering, and wet thin film forming methods generally used such as casting, spin coating, and dipping. Can be mentioned. Of these, the spin coating method is particularly preferable in terms of mass productivity and cost.
[0018]
When the electronic information recording layer 102 is formed as a recording layer made of an inorganic substance, for example, a rare earth transition metal alloy such as Tb / Te / Co or Dy / Fe / Co that is recorded by a magneto-optical effect is used. . Further, chalcogen alloys such as Ge · Te and Ge · Sb · Te that change phase may be used. These layers may be a single layer or may be composed of two or more layers.
[0019]
Examples of the method for forming the electronic information recording layer 102 made of an inorganic substance include vapor deposition, ion plating, and sputtering. Of these, the sputtering method is particularly preferable from the viewpoint of mass productivity and cost. The thickness of the electronic information recording layer 102 varies depending on the type of the recording layer, but the lower limit is usually 5 nm, preferably 10 nm, and the upper limit is usually 500 nm, preferably 300 nm. The electronic information recording layer 102 of the optical information recording medium 100 to which this embodiment is applied may be a phase change recording layer capable of recording / erasing.
[0020]
The reflective layer 103 is provided in contact with the side opposite to the substrate 101 of the electronic information recording layer 102, and usually has a function of reflecting the laser beam 107 irradiated from the substrate 101 side to the substrate 101 side. The reflective layer 103 has an uneven shape corresponding to a recording / reproducing guide groove or pit provided on the substrate 101. Examples of the material for forming the reflective layer 103 include materials having a sufficiently high reflectance at the wavelength of the reproduction light, such as Au, Al, Ag, Cu, Ti, Cr, Ni, Pt, Ta, and Pd. It is possible to use a metal alone or as an alloy. Among these, Au, Al, and Ag have high reflectivity and are suitable as a material for the reflective layer. Further, those containing Ag as a main component are particularly preferable from the viewpoints of low cost and high reflectance.
[0021]
Examples of the method for forming the reflective layer 103 include vapor deposition, ion plating, and sputtering. Of these, the sputtering method is particularly preferable from the viewpoint of mass productivity and cost. The lower limit of the thickness of the reflective layer 103 is usually 30 nm, preferably 50 nm, and the upper limit is usually 150 nm, preferably 120 nm.
[0022]
The protective layer 104 is usually formed of a laser light transmissive material, and examples thereof include an ultraviolet curable resin. Specific examples of the ultraviolet curable resin include acrylate resins such as urethane acrylate, epoxy acrylate, and polyester acrylate. Since most of these materials are laser light transmitting substances, they can be preferably used. These ultraviolet curable resins may be used individually by 1 type, and 2 or more types may be mixed and used for them. Further, the protective layer 104 may be a single-layer film or a multilayer film including two or more layers.
[0023]
As a method for forming the protective layer 104 with an ultraviolet curable resin, an ultraviolet curable resin is usually used as it is or after being dissolved in an appropriate solvent to prepare a coating solution, and then the coating solution is applied onto the reflective layer 103. It can be formed by irradiating with ultraviolet light and curing. In this case, a spin coating method, a casting method, or the like can be employed as a coating method. The protective layer 104 can also be formed by various coating methods described above, various wet film formation methods such as a screen printing method, various dry film formation methods such as a vacuum deposition method, a sputtering method, and an ion plating method. It is formed by a method appropriately selected according to the material to be used. Among these, a wet film forming method, particularly a spin coating method is preferable, and a spin coating method is generally used. The lower limit of the thickness of the protective layer 104 is usually 1 μm, preferably 3 μm, and the upper limit is usually 15 μm, preferably 10 μm.
[0024]
In the visible information recording layer 105, the recording material constituting the layer is usually discolored when irradiated with light. As a result, visible information (images such as characters, symbols, illustrations and photographs, geometric patterns, etc.) , Information read visually). The recording material constituting the visible information recording layer 105 is not particularly limited, but can be broadly classified as a substance that changes the absorption of visible light as follows: (a) a type that changes color development; and (b) a transparent material. And a type whose sex changes.
[0025]
(A) As a type of recording material whose color developability changes, for example, organic dyes generally used for optical recording of electronic information can be mentioned. Such organic dyes include macrocyclic azaannulene dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), polymethine dyes (cyanine dyes, merocyanine dyes, squarilium dyes, etc.), anthraquinone dyes, azurenium dyes, azo dyes Metal-containing azo dyes, metal-containing indoaniline dyes, and the like.
[0026]
Moreover, the leuco dye which has a lactone ring part in molecular structure is mentioned. Specific examples of leuco dyes include 3-diethylamino-7-chloroanilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilino. Fluorane, 3-diethylamino-6-methyl-7-2,4-xylidinofluorane, 3-diethylamino-6-methyl-7- (m-toluidino) -fluorane, 3-diethylamino-7,8-benzofluor Fluorane compounds such as olane, 3-diethylamino-6-methyl-7-xydinofluorane; crystal violet lactone, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl 2-methylindole-3) -Yl) -4-azaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methyl) Ndoru-3-yl) phthalide, 3,3-bis (1-n-butyl-2-methylindole-3-yl) phthalide compounds such phthalide and the like. Of these, phthalide compounds are preferred.
[0027]
These leuco dyes are used in combination with an electron-accepting compound or a dye that generates heat by absorbing a recording laser beam, if necessary. In this case, examples of the electron-accepting compound include an organic phosphoric acid compound having an aliphatic group having 6 or more carbon atoms, an aliphatic carboxylic acid compound, or a phenol compound. Preferably, it is a phenol compound.
[0028]
Specific examples of the electron-accepting compound include dodecylphosphonic acid, tetradecylphosphonic acid, hexadecylphosphonic acid, octadecylphosphonic acid, eicosylphosphonic acid and the like as the organic phosphate compound. Examples of the aliphatic carboxylic acid compound include α-hydroxydecanoic acid, α-hydroxytetradecanoic acid, α-hydroxyhexadecanoic acid, α-hydroxyoctadecanoic acid, α-hydroxypentadecanoic acid, α-hydroxyeicosanoic acid, and α-hydroxydocosane. Examples include acid, α-hydroxytetracosanoic acid, α-hydroxyhexacosanoic acid, α-hydroxyoctacosanoic acid and the like.
[0029]
Examples of the phenol compound include gallic acid compounds, benzoic acid compounds, and bisphenol compounds. Specific examples of these compounds include, for example, methyl gallate, propyl gallate, butyl gallate, lauryl gallate and the like as gallic acid compounds. Examples of the benzoic acid compound include methyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, and 2,4-dihydroxybenzoic acid. Examples of bisphenol compounds include bisphenol S and bisphenol A. Further, 4′-hydroxy-4-octadecylbenzanilide, N-octadecyl-4-hydroxybenzamide, N- (4-hydroxyphenyl) -N′-octadecylurea, 4-hydroxyphenylpropiono-behenyl hydrazide and the like can be mentioned. These electron accepting compounds may be used alone or in combination of two or more.
[0030]
Examples of the laser light absorbing dye include various dyes listed above as organic dyes used for optical recording of electronic information, and bisanthrone-based, indoaniline-based infrared absorbing dyes, and the like.
[0031]
Next, (b) a recording material of a type whose transparency changes includes, for example, an organic low-molecular compound that is dispersed in a resin base material at about 0.1 to 2 μm and melts or crystallizes by heat treatment. As such a compound, for example, a well-known organic low molecular weight compound such as a higher fatty acid having 12 or more carbon atoms can be used. Such an organic low molecular weight compound may be a compound composed of a fatty acid, an aliphatic dibasic acid, a ketone, an ether, an alcohol, a fatty acid ester and a derivative thereof, or a mixture of one or more of them. It can also be used.
[0032]
Of the organic low molecular weight compounds that are melted or crystallized by heat treatment, fatty acid alkyl esters having 12 or more carbon atoms are those having a low melting point (mp) and are preferable because they melt and crystallize by heat treatment at a relatively low temperature. Furthermore, in addition to the fatty acid alkyl ester having 12 or more carbon atoms, an aliphatic dibasic acid having a high melting point (mp) having 10 or more carbon atoms is used in combination, and the blending ratio of the fatty acid alkyl ester and the aliphatic dibasic acid is adjusted. The temperature range to be transparent can be adjusted, and the degree of transparency and cloudiness at a predetermined temperature can be changed.
[0033]
Examples of fatty acid alkyl esters having 12 or more carbon atoms include methyl stearate, ethyl stearate, butyl stearate, octyl stearate, stearyl stearate, behenyl stearate, methyl behenate, ethyl behenate, butyl behenate, behen Examples include octyl acid, stearyl behenate, behenyl behenate, methyl lignocerate, ethyl lignocerate, and the like.
[0034]
Examples of the aliphatic dibasic acid having 10 or more carbon atoms include sebacic acid, dodecanedioic acid, tetradecanedioic acid, and eicosanedioic acid. When the fatty acid alkyl ester having 12 or more carbon atoms and the aliphatic dibasic acid having 10 or more carbon atoms are used in combination, the mixing ratio is preferably about 1: 1 to 10: 1, and more preferably 2: 1 to 6: 1. . Since the aliphatic dibasic acid on the high melting point side is considered to play a role in manipulating the crystallization behavior as a seed crystal of the fatty acid alkyl ester on the low melting point side, the effect may be lost if the amount is too small. On the other hand, if the amount is too large, the contrast may be lowered.
[0035]
Examples of the method for forming the visible information recording layer 105 include known wet thin film forming methods as mentioned in the section for the method for forming the electronic information recording layer 102. Among these, a spin coating method or a screen printing method is preferable, and a spin coating method is more preferable. The lower limit of the thickness of the visible information recording layer 105 is usually 0.1 μm, preferably 0.5 μm, and the upper limit of the thickness is usually 5 μm, preferably 3 μm.
[0036]
In the optical information recording medium 100 to which this embodiment is applied, a hydrophilic overcoat layer 106 is provided on the outermost layer on the label surface side of the visible information recording layer 105. The hydrophilic overcoat layer 106 protects the visible information recording layer 105 from physical scratches and the like, and has a laser beam transparency to efficiently narrow down the laser beam 108 to the visible information recording layer 105, and For example, a surface that can be printed by an ink jet printer is formed. That is, the hydrophilic overcoat layer 106 has a function as a print receiving layer in addition to the role of protecting the visible information recording layer 105 from an external force or the like, and enables colorization of visible information. Also, for example, visible information is recorded on a part of the visible information recording layer 105 by laser light, the other part is printed by an ink jet printer, and the recorded part of the visible information recording layer 105 is rewritten as necessary. You can use it as you say. A laser light transmitting layer may be interposed between the hydrophilic overcoat layer 106 and the visible information recording layer 105. Furthermore, the hydrophilic overcoat layer 106 needs to be laser beam transmissive, but may be colored with respect to visible light.
[0037]
The method for constructing such a laser light transmitting hydrophilic overcoat layer 106 is not particularly limited. For example, (1) a method of constructing a layer using a hydrophilic resin and / or a hydrophilic monomer, (2 And a method of dispersing a hydrophilic filler in the binder resin, and a method of forming a fine void by dispersing fine particles in the binder resin. Among these, (3) a method of forming fine voids by dispersing fine particles in a binder resin is particularly preferable. These methods can be employed singly or in combination.
[0038]
(1) As a hydrophilic resin used in the case of constituting a layer using a hydrophilic resin, for example, polyethylene oxide, polyvinyl alcohol, polyvinyl methyl ether, polyvinyl formal, carboxyvinyl polymer, hydroxyethyl cellulose, hydroxypropyl cellulose, Examples include methyl cellulose, carboxymethyl cellulose sodium salt, and polyvinylpyrrolidone.
[0039]
The hydrophilic monomer used when the hydrophilic overcoat layer 106 is formed by polymerizing the hydrophilic monomer is, for example, a monomer having at least one ethylenically unsaturated bond in the molecule. Is preferred. Specifically, mono- or poly (meth) acrylate having a hydroxyl group such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; alkylene oxide-modified phosphate mono- or di (meth) acrylate, caprolactone-modified phosphate mono- or Examples thereof include mono- or poly (meth) acrylate having a phosphate group such as di (meth) acrylate. Examples of the compound having a functional group containing a nitrogen atom include (meth) acrylamide derivatives such as alkyl-substituted (meth) acrylamide, alkoxy-modified (meth) acrylamide and methylol-modified (meth) acrylamide; N, N-dimethylaminoethyl ( Mono- or poly (meth) acrylates having amino groups such as (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate; acryloylmorpholine, N-vinyloxazolidone, N-vinylsuccinimide, N-vinylpyrrolidone, N -Vinyl caprolactam etc. are mentioned. Further, polyether-modified mono- or poly (meth) acrylate, mono- or diacrylate having a polyethylene glycol unit, polyhydric alcohol diglycidyl ether mono- or poly (meth) acrylate, and the like can also be used. These hydrophilic monomers are active energy ray-curable and are usually polymerized by irradiation with active energy rays such as light in the presence of a photoinitiator.
[0040]
(2) The hydrophilic filler used in the method of dispersing the hydrophilic filler in the binder resin includes an organic filler and an inorganic filler. Examples of the organic filler include acrylic resin, polyacrylic acid ester, polymethacrylic acid ester, styrene resin, polyester, polycarbonate, modified melamine resin fine particles, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, fine particles such as rubber, or polymers of these. Examples thereof include crosslinked fine particles, lignin, protein, and cellulose powder. Examples of the inorganic filler include silica, talc, clay, calcium carbonate, calcium silicate, barium sulfate, mica, diatomaceous earth silica, aluminum hydroxide, alumina, zirconium oxide, zirconium hydroxide and the like.
[0041]
As the binder resin for dispersing the hydrophilic filler, for example, the hydrophilic resin mentioned in the above (1) can be used. Further, since the hydrophilic filler itself is hydrophilic, it is not necessarily limited to the hydrophilic resin, and other resins can be used as long as the hydrophilic filler can be favorably dispersed as the binder resin. Examples of such other resins include conjugated diene polymers such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer; polymers or copolymers of acrylic acid ester and / or methacrylic acid ester, and the like. Acrylic polymers; vinyl polymers such as ethylene vinyl acetate copolymer; and the like. In addition, monomers constituting these various polymers, functional group-containing monomers such as carboxyl groups, and functional group-modified polymers such as copolymers; thermosetting synthetic resin systems such as melamine resins and urea resins, etc. Water-based adhesive and the like. Further examples include polyurethane resins, unsaturated polyester resins, polyvinyl butyral, alkyd resins, and the like. These other resins can be used in the form of a resin latex as required.
[0042]
(3) As a method of forming the hydrophilic overcoat layer 106 in which fine particles are dispersed in a binder resin to form fine voids, for example, a resin composition containing fine particles having an average particle size of 200 nm or less and a cationic resin is used. The method used is preferable (for example, the method described in JP-A No. 2000-57635). According to this method, fine voids are formed by containing a predetermined amount of fine particles in the binder resin, and for example, ink used for printing can be instantaneously absorbed in the layer by capillary action.
[0043]
Examples of the fine particles having an average particle diameter of 200 nm or less contained in such a resin composition include various organic and inorganic fine particles. Examples of the fine particles made of an organic material include synthetic resin particles such as polymethyl methacrylate (PMMA) resin, polystyrene resin, epoxy resin, fluorine resin, silicon resin, and polyester resin; natural resin particles such as collagen, silk, and cotton. . Examples of the fine particles made of an inorganic material include silica, talc, mica, oxides of various metals such as aluminum, magnesium, zinc, iron, manganese, and titanium, and ceramics. Among these, silica is suitable because it has a large specific surface area and can form fine voids, and because the surface is hydrophilic, the compatibility with water-based inks is good. Furthermore, synthetic silica is recommended in that the particle size, specific surface area, and the like can be controlled by the production method, and spherical and uniform fine particles can be obtained. The size of the void formed by dispersing these fine particles is preferably in the range of several nanometers to several tens of nanometers from the viewpoint of effectively absorbing ink of an ink jet printer, for example.
[0044]
The average particle diameter of these fine particles is 200 nm or less, preferably 100 nm or less, and more preferably 50 nm or less in order to obtain a fine and high porosity. Moreover, it is 1 nm or more normally, Preferably it is 2 nm or more. If the average particle size is excessively large, the proportion of particles having a particle size exceeding ¼ of the visible light wavelength increases, and the transparency of the hydrophilic overcoat layer 106 decreases. The visibility of the visible information recording layer 105 provided on the side tends to be reduced. When the average particle size is excessively small, voids between particles in the hydrophilic overcoat layer 106 become small, and it may be difficult to effectively absorb ink.
[0045]
Moreover, the compounding quantity of the microparticles | fine-particles in the hydrophilic overcoat layer 106 is 10 weight% or more normally with respect to a resin composition, Preferably it is 20 weight% or more. Further, it is usually less than 70% by weight, preferably 50% by weight or less, more preferably 40% by weight or less. When the content of the fine particles is excessively large, the transparency of the hydrophilic overcoat layer 106 is lowered, and the visibility of information recorded in the visible information recording layer 105 tends to be lowered. Further, the recording sensitivity of the visible information recording layer 105 may decrease due to a decrease in the transmittance of the recording laser beam 108 for recording the visible information. For this reason, the content of the fine particles contained in the hydrophilic overcoat layer 106 is usually compared with the content in the ink receiving layer (the outermost layer of the optical disc that can be recorded by an inkjet printer or the like) in an optical disc such as a CD-R. Thus, a small amount is preferable.
[0046]
The cationic resin contained in the resin composition is considered to have a function of insolubilizing the ink in order to impart water resistance to the image printed by the ink jet printer. Such a cationic resin is not particularly limited as long as it contains a cationic moiety in the molecule, but the weight average molecular weight is usually 500 or more, preferably 1,000 or more. Also, it is usually in the range of 200,000 or less, preferably 100,000 or less. When the weight average molecular weight is less than 500, the water resistance of the image tends to be inferior, and when it exceeds 200,000, the binding efficiency with the dye molecule due to steric hindrance due to the molecular structure tends to be deteriorated. The effect by addition becomes small.
[0047]
Examples of such cationic resins include polyacrylamide cation-modified products; acrylamide and cationic monomer copolymers; tertiary amino group-containing (meth) acrylate cation-modified products and other copolymerizable monomers. Copolymers: Vinyl pyrrolidone monomers, vinyl oxazolidone monomers, or vinyl imidazole monomers and other copolymerizable monomers. Moreover, polyallylamine, polyamine sulfone, polyvinylamine, polyethyleneimine, polyamide epichlorohydrin, polyvinylpyridinium halide, etc. are mentioned. Furthermore, a copolymer of a cation-modified product of a tertiary amino group-containing (meth) acrylate represented by the general formula in paragraph (0025) of JP-A-2000-57635 and another copolymerizable monomer is mentioned. It is done.
[0048]
The binder resin used in the method of forming the fine voids by dispersing the fine particles in the binder resin of the hydrophilic overcoat layer 106 is the hydrophilic resin mentioned in the above (1), and mentioned in the above (2). Other resin etc. are mentioned. Further, as the binder resin, it is preferable to use an ultraviolet curable resin containing an ultraviolet curable monomer or oligomer. In general, in the case of an ultraviolet curable resin, no solvent is required or the amount of solvent used is small, and when a layer formed by coating or the like is cured, high temperature or long time heating is not required. The point where there is little adverse effect of is preferable.
[0049]
As such an ultraviolet curable resin, a radical reaction type resin is preferably used. The radical reaction type ultraviolet curable resin is usually prepared using at least a resin oligomer component and a photopolymerization initiator, and further using a resin monomer component as necessary. By selecting various resin oligomer components and resin monomer components, print receiving layers having various characteristics can be obtained.
[0050]
Examples of such resin oligomer components include acrylic oligomers, ester oligomers, urethane oligomers, and ether oligomers. Examples of acrylic oligomers include (meth) acrylic acid polymers; alkyl (meth) such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Examples include acrylate polymers. Furthermore, the copolymer of (meth) acrylic acid or alkyl (meth) acrylate and the other monomer copolymerizable with these monomers is mentioned. Other monomers that can be copolymerized include aromatic vinyl compounds such as styrene, α-methylstyrene, (o, m, p) vinylphenol; vinyl carboxylic acid compounds such as maleic acid, itaconic acid, crotonic acid, and fumaric acid. Glycidyl group-containing vinyl compounds such as glycidyl (meth) acrylate, allyl glycidyl ether, glycidyl ethyl acrylate, crotonyl glycidyl ether, and glycidyl crotonic acid; aromatic acrylate compounds such as benzyl (meth) acrylate; hydroxyethyl (meth) acrylate Substituted alkyl acrylate compounds such as N, N-dimethylaminoethyl (meth) acrylate; (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylamino ester Le (meth) acrylamide compounds such as acrylamide; vinyl acetate, (meth) acrylonitrile, (meth) acrylic acid chloride, N- (meth) acryloyl morpholine and the like.
[0051]
Examples of the ester oligomer include an ester of polyester diol and acrylic acid made of a ring-opening polymer of phthalic anhydride and propylene oxide; an ester of polyester diol and acrylic acid made of 1,6-hexanediol adipic acid An ester of triol consisting of a reaction product with trimethylene acid diethylene glycol and acrylic acid; a ring-opening polymer of δ-valerolactone and an ester of acrylic acid;
[0052]
Further, as the urethane oligomer, for example, a reaction product of polyurethane composed of hexamethylene diisocyanate and 1,6-hexanediol and 2-hydroxyethyl acrylate; polyester diol composed of adipic acid and 1,6-hexanediol and tolylene diene The thing etc. which made 2-hydroxyethyl acrylate react with the diisocyanate oligomer which was made to react with isocyanate are mentioned.
[0053]
Examples of the ether oligomer include esters of polypropylene glycol and acrylic acid. In addition, epoxy oligomers, polyarylate, and the like obtained by reacting an acrylate with an epoxy resin can also be used as the resin oligomer component.
[0054]
The resin monomer component may be either a monofunctional monomer or a polyfunctional monomer, but preferably contains a certain amount of the polyfunctional monomer component in order to increase the crosslink density in the print receiving layer and maintain strength. . Examples of the monofunctional monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, N-vinylpyrrolidone, 2-hydroxyethylacryloyl phosphate, tetrahydrofurfuryl acrylate. , Tetrahydrofurfuryloxyethyl acrylate, tetrahydrofurfuryloxyhexanolide acrylate, acrylate of ε-caprolactone adduct of 1,3-dioxane alcohol, 1,3-dioxolane acrylate, and the like.
[0055]
Polyfunctional monomer components include cyclopentenyl acrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, polyethylene glycol (400) diacrylate, hydroxypivalate ester neo Pentyl glycol diacrylate, dipentyl neopentyl glycol adipate, diacrylate of ε-caprolactone adduct of neopentyl glycol hydroxypivalate, 2- (2-hydroxy-1,1-dimethylethyl) -5-hydroxymethyl-5 -Ethyl-1,3-dioxane diacrylate, tricyclodecane dimethylol diacrylate, tricyclodecane dimethylol diacrylate ε-caprolactone adduct, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, propionic acid / dipentaerythritol triacrylate, hydroxypivalaldehyde-modified dimethylolpropane triacrylate, propionic acid / dipentaerythritol Examples include tetraacrylate and ditrimethylolpropane tetraacrylate.
[0056]
The ultraviolet curable resin composition contains a photopolymerization initiator. Examples of the photopolymerization initiator include benzoin isopropyl ether, benzophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, 2,4-diethylthioxanthone, methyl o-benzoylbenzoate, 4,4. -Bisdiethylaminobenzophenone, 2,2-diethoxyacetophene, benzyl, 2-chlorothioxanthone, diisopropylthioxanthone, 9,10-anthraquinone, benzoin, benzoin methyl ether, 2,2-dimethoxy-2-phenylacetophenone, 2, -Hydroxy-2-methyl-propiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, α, α-dimethoxy-α-phenylacetone and the like. In addition to the above, the ultraviolet curable resin composition may contain a polymerization terminator, a storage stabilizer, a dispersant, an antifoaming agent, a binder resin other than the ultraviolet curable resin, and the like, if necessary.
[0057]
Note that (3) not only when the hydrophilic overcoat layer 106 is formed by a method of dispersing fine particles forming fine voids in the binder resin, but also (1) using a hydrophilic resin and / or a hydrophilic monomer. In the case of the method of forming the layer and (2) the method of dispersing the hydrophilic filler in the binder resin, the material for forming the hydrophilic overcoat layer 106 is preferably UV curable. For example, in the case of (1), each component which comprises the ultraviolet curable resin mentioned above can be used together with a hydrophilic resin or a hydrophilic monomer. Further, in the case of (2), part or all of the binder resin can be replaced with each component constituting the ultraviolet curable resin described above. As the most preferable form as the hydrophilic overcoat layer 106 in the optical information recording medium 100 provided with the present embodiment, in the method (3), ultraviolet curing containing fine particles having an average particle diameter of 200 nm or less and a cationic resin. It is the layer formed using the conductive resin composition.
[0058]
The hydrophilic overcoat layer 106 is preferably formed by a wet film forming method using the various organic substances described above. As the wet film forming method, a spin coating method, a casting method, a screen printing method, or the like can be employed as in the protective layer 104 described above. Among these, the spin coating method is preferable from the viewpoint of particularly high surface smoothness. In particular, when the hydrophilic overcoat layer 106 is formed, if a transparent substrate previously made of a laser light transmissive material is to be bonded, it is necessary to perform accurate alignment of the substrate, and to the adhesive layer. Various measures on the manufacturing process are required, such as reducing the bonding process to prevent bubbles from entering. Therefore, from the viewpoint of productivity, it is advantageous to provide the hydrophilic overcoat layer 106 by a wet film forming method such as spin coating or screen printing.
[0059]
The lower limit of the thickness of the hydrophilic overcoat layer 106 is 10 μm, preferably 20 μm, and the upper limit of the thickness is 100 μm, preferably 80 μm. When the thickness of the hydrophilic overcoat layer 106 is lower than the lower limit value, there is a possibility that a sufficient protective function of the visible information recording layer 105 cannot be maintained. Further, when the thickness is higher than the upper limit value, when the hydrophilic overcoat layer 106 is formed by coating, overcoating or the like is required, and the formation process becomes complicated. Furthermore, there is a possibility that problems such as an increase in warpage of the disk due to curing shrinkage of the coating material may occur. The reflectance on the surface of the hydrophilic overcoat layer 106 is preferably 20% or less, for example. In this case, the refractive index of the hydrophilic overcoat layer 106 is preferably about 0.4 to 2.6. In order to make the reflectance on the surface of the hydrophilic overcoat layer 106 10% or less, the refractive index of the hydrophilic overcoat layer 106 is preferably 0.5 or more and 1.9 or less.
[0060]
The optical information recording medium 100 to which this embodiment is applied may have an arbitrary layer other than those described above. For example, when a recording layer made of an inorganic substance is used as the electronic information recording layer 102, an arbitrary layer is provided between each layer or the outermost layer of the medium, such as a dielectric layer sandwiching the electronic information recording layer 102. May be.
[0061]
【Example】
The optical information recording medium to which the present embodiment is applied will be described more specifically with reference to the following examples. The present embodiment is not limited to the examples. Moreover, all parts and% in the examples are based on weight.
(Recording method of visible information on optical information recording medium)
FIG. 2 is a diagram for explaining a recording apparatus for recording visible information on an optical information recording medium having a visible information recording layer. The recording apparatus 200 shown in FIG. 2 is configured so that visible information can be recorded on an optical information recording medium 11 having a visible information recording layer by a normal optical disk drive, and the optical information recording medium 11 is mounted. A spindle 12, a spindle motor 13 that rotates the spindle 12, a feed feeding stepping motor 14, a screw shaft 15 that is rotated by the stepping motor 14, and a pickup 16 that is moved to an arbitrary position are provided.
[0062]
As shown in FIG. 2, in this recording apparatus 200, an optical information recording medium 11 is mounted on a spindle 12 and rotated by a spindle motor 13, and a screw shaft 15 is rotated by a stepping motor 14 for feed feed. The pickup 16 is moved to the position. The spindle motor 13 is servoed by an FG pulse signal, and the optical information recording medium 11 is adjusted to an arbitrary rotational speed. A focus servo is used to focus on the surface of the optical information recording medium 11, the laser light 17 is condensed, and visible information is written on the optical information recording medium 11. At this time, the laser power is controlled by the front monitor so that it can be written with an appropriate power. The write signal is irradiated with a pulse having a duty of about 50% on the surface of the optical information recording medium 11 with an output of 40 to 50 mW. The spindle rotation speed is 160 to 2560 rpm.
[0063]
(Example)
A polycarbonate resin substrate having a groove with a width of 0.45 μm and a depth of 155 nm and a thickness of 1.2 mm was formed by injection molding. On this substrate, a fluoroalcohol solution of a metal-containing azo dye was applied by spin coating and dried at 90 ° C. for 15 minutes to form an electronic information recording layer having a thickness of 70 nm. Next, Ag was sputtered on the electronic information recording layer to form a reflective layer having a thickness of 70 nm. Further, an ultraviolet curable resin mainly composed of an acrylate monomer (“SD-374” manufactured by Dainippon Ink Co., Ltd.) is applied on the reflective layer by spin coating, and then cured by irradiation with ultraviolet light to obtain a thickness. A 7 μm protective layer was formed to produce a CD-R. Subsequently, on this protective layer, 0.2 part of phthalide leuco dye, 0.6 part of electron accepting compound composed of a phenol compound, 0.05 part of bisanthrone infrared absorbing dye, and polymethacrylic acid A chromogenic organic dye composition comprising 4 parts of methyl (10% toluene solution) and 2 parts of toluene was applied by spin coating and dried at 50 ° C. for 30 minutes to form a visible information recording layer. .
[0064]
Furthermore, on this visible information recording layer, 30 parts of synthetic silica having a primary average particle size of 10 nm and a pore volume of 3 ml / g, 35 parts of acryloylmorpholine, 10 parts of hydroxyethyl acrylate, a cationic resin (manufactured by Mitsubishi Chemical Corporation) A UV-curable resin composition containing 3 parts of saftomer and 2 parts of a photopolymerization initiator was applied by spin coating, cured by irradiating with UV light, and a hydrophilic overcoat layer (refractive index of 1) having a thickness of 20 μm. 5) to produce an optical information recording medium.
[0065]
The optical information recording medium thus produced is set in the recording apparatus 200 shown in FIG. 2, and a low-power laser beam having a wavelength (λ) of 780 nm and an output of 50 mw is irradiated from the label surface side of the optical information recording medium. When visible information was recorded on the visible information recording layer, focusing was very stable and visible information could be recorded. Moreover, when it printed on the hydrophilic overcoat layer using the inkjet printer (Epson PM-950C), the favorable printing which does not have a bleeding and mixed color between different colors was performed.
[0066]
【The invention's effect】
Thus, according to the present invention, a label surface capable of recording visible information without affecting the electronic information recorded on the medium by irradiating with low-power laser light and capable of being printed using an ink jet printer. An optical information recording medium is provided.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the structure of an optical information recording medium to which the present embodiment is applied.
FIG. 2 is a diagram for explaining a recording apparatus for recording visible information on an optical information recording medium having a visible information recording layer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11,100 ... Optical information recording medium, 12 ... Spindle, 13 ... Spindle motor, 14 ... Stepping motor, 15 ... Screw shaft, 16 ... Pickup, 17 ... Laser beam, 101 ... Substrate, 102 ... Electronic information recording layer, 103 ... Reflective layer, 104 ... protective layer, 105 ... visible information recording layer, 106 ... hydrophilic overcoat layer, 107 ... laser beam, 108 ... laser beam, 109 ... reflected beam, 200 ... recording device

Claims (5)

A substrate,
Visible information recording layer provided on the substrate directly or via another layer, in which visible information is recorded by light irradiated from a label surface side opposite to the substrate side,
A hydrophilic overcoat layer provided directly or via another layer on the visible information recording layer ,
The optical information recording medium, wherein the hydrophilic overcoat layer is transparent to laser light .   2. The optical information recording medium according to claim 1, wherein the hydrophilic overcoat layer is composed of an ultraviolet curable resin composition containing fine particles having an average particle diameter of 200 nm or less and a cationic resin. The hydrophilic overcoat layer is a lower limit of the thickness is 10μm of the hydrophilic overcoat layer, an optical information recording according to claim 1 or 2, characterized in that the upper is formed in a range of 100μm Medium. The visible information recording layer, claims 1 to 3 any one, characterized in that the material or transparency chromogenic the light having irradiated the visible information recording layer is changed is made of a material which changes The optical information recording medium described. An electronic information recording layer provided on the substrate directly or via another layer, on which electronic information is recorded by light irradiated from the substrate side;
A reflective layer formed on the side opposite to the substrate side of the electronic information recording layer,
The visible information recording layer, the optical information recording medium according to any one of claims 1 to 4 and the substrate side of the reflective layer, characterized in that it is formed on the opposite side.

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