JP2000057635A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical recording medium suitable for printing characteristics of a full-color liquid ink jet printer by forming a print accepting layer on an outermost layer from a UV-setting resin compsn. containing a cation resin and fine particles in a specified range of the particle size. SOLUTION: Fine particles having mean particle diameter of <=200 nm are dispersed in a printing accepting layer. The fine particles are preferably silica particles from the viewpoints of heat resistance, water resistance, solvent resistance, easy to be pulverized, large in a specific surface area and a hydrophilic surface. The particle size and the specific surface area of synthetic silica can be controlled by a producing method and the spherical and uniform fine particles can be obtd. In order to obtain porous silica having a large specific surface, a wet method is preferable. The compounding amt. of the fine particles in the print accepting layer is set to 30 to 100 wt.% to the UV-setting resin compsn. to obtain fine pores with high porosity in order to effectively absorb inks applied by an ink jet printer. Fine vacancies which can instantly absorb the ink by a capillary phenomenon are formed to control bleeding, to increase the absorption rate, to improve drying property and to form a shape image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium, and more particularly, to an optical recording medium having a surface layer (print receiving layer) that allows writing with various writing tools and printing with various printers. The surface layer of the optical recording medium of the present invention is particularly excellent in printing characteristics, storage stability and print water resistance by a full-color liquid inkjet printer.

[0002]

2. Description of the Related Art An optical recording medium (optical disk) on which information can be written and / or read by a laser has a larger recording capacity and a random access than conventional recording media. It is widely used as a recording medium in fields such as computer software, game software, and electronic publishing.

[0003] Optical recording media are classified into two types: a write-once type, on which information can be recorded and reproduced, and a rewritable type, on which data can be erased after recording. Among them, CD-type optical information media CD-R (write-once type) and CD-RW (rewriteable type)
In recent years, the number of users has rapidly increased. These CDs
Can write and use various information and data unique to each user, and furthermore, the CD-R
Compatible with read-only CDs. Recently, DVD
Optical recording media DVD-R (write-once), DVD
-RW (rewritable type) etc. are also beginning to spread.

It is preferable that a user of the optical recording medium as described above can see at a glance what information is recorded on the medium. In addition, in the case of a company that handles small-volume and various kinds of information media, such as putting the data into the media and selling the media to end users, from the viewpoint of product labeling, the surface of the media must be written with various writing tools. And printability by various printers are required.

As a method for writing on the surface of a medium as described above, a method of directly attaching a paper or film label to the surface of the medium has been proposed, and such a method is based on a character designed beautifully by a printer. It has the advantage of being able to print pictures and pictures, but has the following disadvantages.

(1) When a label is partially applied to the surface of a medium, rotation blur occurs due to the weight of the label, and a read signal error easily occurs at high speed rotation. (2) When a label is applied to the entire surface of the medium, a donut-shaped label is used. However, it is very difficult to align the label with the medium, and a positional deviation of about 0.5 mm may occur. Therefore, an error easily occurs in the read signal of the high-speed rotation. (3) The label is stuck with an adhesive, and if it comes off, there is a possibility that it will come off and be caught in the device. (4) When a paper label is attached, the medium is deformed due to moisture absorption / dehumidification due to the environment of the adhesive and the paper.

For the above reasons, in recent years, optical recording media capable of directly printing on the surface opposite to the light incident surface of the optical recording medium (hereinafter referred to as a label surface) and printers dedicated to such media have been sold. It has become. An aqueous liquid ink jet recording method is widely used as a print recording method for these printers. This recording method is widely used since a clear full-color image can be obtained at relatively low cost.

As means for improving the writeability and printability of the label surface of an optical recording medium, for example, JP-A-7-16
No. 9100 discloses an optical recording in which a printable protective layer (outermost layer) is formed from an ultraviolet-curable resin composition containing a hydrophilic polymer, a hydrophilic monomer, and a water-absorbing / oil-absorbing organic / inorganic filler. A medium has been proposed.

[0009] However, the protective layer of the optical recording medium is said to prevent repelling of the printing ink and has excellent fixability of the printing ink due to the hydrophilic polymer. Is not enough,
The ink that cannot be absorbed bleeds, the image becomes unclear, and the ink dries slowly, leaving the ink sticky after printing. In addition, the water resistance of the protective layer itself is not sufficient, and after printing, the printing ink elutes due to the adhesion of water and becomes decolorized, and the printing ink bleeds in a high humidity atmosphere. is there.

On the other hand, as means for improving the water resistance, for example, Japanese Patent Application Laid-Open No. 9-245379 discloses an ink receiving layer containing a vinyl acetal resin, an alumina hydrate and a cationic resin in a specific ratio. Optical information media have been proposed. However, the above ink receiving layer is
In the formation process, it is necessary to heat dry using a hot air dryer, a hot drum, etc., and therefore, productivity is poor,
There is a problem such as deterioration of characteristics of the optical information medium due to heat.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a printable optical recording medium in which a print receiving layer formed on the surface thereof has
It has sufficient ink absorption speed and ink absorption capacity to form a clear image without bleeding by inkjet, and the print receiving layer has its own water resistance and the water resistance of the printed image formed on the layer. Another object of the present invention is to provide an optical recording medium having both high productivity and high productivity.

[0012]

Means for Solving the Problems The present inventors have made intensive studies and as a result, have found that an optical recording medium having excellent ink absorption and good water resistance can be obtained by forming a specific structure of a print receiving layer. Were obtained, and the present invention was completed.

That is, the gist of the present invention is to provide a print receiving layer as an outermost layer of a medium, wherein the print receiving layer has an average particle diameter of 200.
An optical recording medium comprising an ultraviolet curable resin composition containing fine particles having a diameter of not more than nm and a cationic resin.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The fundamental difference between the print receiving layer in the optical recording medium of the present invention and the conventional print receiving layer is the ink absorption mechanism of the ink jet printer.

That is, in the conventional print receiving layer, the resin constituting the layer itself has an ink absorbing property, or the water-absorbing fine particles dispersed in the binder resin layer constituting the layer absorb the ink. Has enabled printing. On the other hand, in the case of the present invention, by including a predetermined amount of fine particles in the print receiving layer, it is possible to form fine voids in which the ink is instantly absorbed by the capillary phenomenon in the print receiving layer. . According to this method, a large amount of ink can be absorbed, so that the spread (bleeding) of the ink on the surface of the print receiving layer can be controlled, and the absorption speed can be increased. Can be formed.

The print receiving layer according to the present invention has an average particle size of 2
It is composed of an ultraviolet curable resin composition containing fine particles having a size of 00 nm or less and a cationic resin.

The fine particles include various fine particles of organic and inorganic substances. For example, examples of the fine particles made of an organic material include synthetic resin particles such as PMMA resin, polystyrene resin, epoxy resin, fluororesin, silicone resin, and polyester resin, and natural resin particles such as collagen, silk, and cotton. Examples of inorganic fine particles include oxides of various metals such as aluminum, magnesium, zinc, iron, manganese, and titanium, as well as talc and mica, and ceramics. Fine particles made of an organic material are difficult to be reduced to a particle size of 100 nm or less, and inorganic particles are preferable because they tend to have poor heat resistance, water resistance, solvent resistance, and the like. Among the inorganic fine particles, various metal oxides are preferable because they are easily atomized. In particular, silica has a large specific surface area,
Fine voids can be formed, and since the surface is hydrophilic, the affinity with the aqueous ink is good, which is preferable.

[0018] Synthetic silica is recommended because its particle size and specific surface area can be controlled by the production method, and spherical fine particles having uniform characteristics can be obtained. There are a dry method and a wet method as a method for synthesizing the synthetic silica, and a wet method is preferable for obtaining porous silica having a large specific surface area. Further, the wet method includes a precipitation method and a gel method, and any of them may be used.

The size of the voids of the fine particles is preferably in the range of several nm to several tens nm from the viewpoint of effectively absorbing the ink jet ink. Although the print receiving layer in the present invention contains fine particles and a cationic resin, the dispersibility and particle size of the fine particles in the ultraviolet-curable resin composition are important for effectively obtaining the fine voids as described above. .

The average particle size of the fine particles must be 200 nm or less in order to obtain a fine and high porosity. That is, when the average particle size exceeds 200 nm, the voids formed between the fine particles become coarse, the ink absorbing ability and the absorbing speed are reduced, and sufficient ink receptivity cannot be obtained. Also,
Since the ultraviolet ray transmittance is low and the photo-curing of the print receiving layer is not sufficiently performed, the inside of the layer is hardly cured, and the productivity tends to be poor. The average particle size of the fine particles is preferably 1 to 100 n.
m, more preferably 2 to 50 nm. Average particle size is 1
If it is less than nm, the dispersibility in the binder resin tends to decrease, and the gap formed between the particles tends to be too fine, so that sufficient ink receptivity tends not to be obtained.

The content of the fine particles in the print receiving layer is 30 to the ultraviolet curable resin composition forming the print receiving layer.
% By weight and less than 100% by weight, preferably 30% by weight and 95% by weight, more preferably 35% by weight and 90% by weight. If it is less than 30% by weight, it is difficult to form a void having a size necessary for ink absorption.

The cationic resin contained in the ultraviolet curable resin composition is considered to have a function of insolubilizing the ink in order to impart water resistance to an image printed by ink jet. In general, anionic water-soluble dyes are used in inks for inkjet printers, and the addition of a cationic resin can make the dyes in the ink adsorbed in the fine voids insoluble in water, giving water resistance to the formed image. it can.

The cationic resin that can be used in the present invention is not particularly limited as long as it contains a cationic moiety in the molecule, but the weight average molecular weight is usually 500 to 20.
000, preferably in the range of 1,000 to 100,000. When the weight average molecular weight is less than 500,
When the water resistance of the image tends to be inferior, and when it exceeds 200,000, the binding efficiency with the dye molecule tends to be deteriorated due to the steric hindrance of the molecular structure, so that the effect of adding a small amount is small.

Examples of the cationic resin include a cationically modified polyacrylamide, a copolymer of acrylamide and a cationic monomer, and a copolymer of a cationically modified tertiary amino group-containing (meth) acrylate with other general monomers. Examples include polymers, polyallylamine, polyamine sulfone, polyvinylamine, polyethyleneimine, polyamide epichlorohydrin, polyvinylpyridinium halide, and the like. Further, a copolymer of a vinylpyrrolidone-based monomer, a vinyloxazolidone-based monomer, or a vinylimidazole-based monomer with another general monomer may be used. Further, a copolymer of a cationically modified tertiary amino group-containing (meth) acrylate represented by the following general formula and another general monomer may be used. In the following general formula,
R represents a hydrogen atom or a methyl group.

[0025]

Embedded image

In general, as a means for forming a print receiving layer on paper or film, a method is known in which a composition containing a resin soluble in water or another solvent as a binder is applied and dried. In this case, of course, the water resistance and solvent resistance of the print receiving layer itself are weak. Further, the drying time requires at least several minutes, which is not preferable in terms of productivity in the process of manufacturing an optical recording medium. Further, the characteristics of the medium may be deteriorated due to the influence of the drying heat. On the other hand, in the present invention, by using a resin composition (ultraviolet curable resin composition) using an ultraviolet (UV) curable resin as a binder, a print receiving layer having high water resistance and solvent resistance of the layer itself is formed. it can.

In general, UV-curable resins are classified into radical reaction type resins and ion reaction type resins. In general, ion reaction type resins have a low reaction rate, and thus radical reaction type resins are preferably used.

The radical reaction type UV-curable resin is usually prepared by using at least a resin monomer component and a photopolymerization initiator and, if necessary, a resin oligomer component. By variously selecting a resin monomer component and a resin oligomer component, a print receiving layer having various characteristics can be obtained. That is, the viscosity and hardness change depending on the type and amount of the resin monomer component, and the hardness, adhesion, water resistance, moisture resistance, and the like change depending on the type and amount of the resin oligomer component.

The resin monomer component may be either a monofunctional or polyfunctional monomer. In order to maintain the strength by increasing the crosslink density in the print receiving layer, it is preferable to include a certain amount of a polyfunctional monomer component.

Examples of the monofunctional monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, N-vinylpyrrolidone, 2-hydroxyethylacryloyl phosphate, tetrahydroethyl Furfuryl acrylate, tetrahydrofurfuryloxyethyl acrylate, tetrahydrofurfuryloxy hexanolide acrylate, ε of 1,3-dioxane alcohol
Acrylates of caprolactone adduct, 1,3-dioxolan acrylate and the like.

Examples of the polyfunctional monomer component include cyclopentenyl acrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, polyethylene glycol (400) diacrylate, and hydroxypivalin. Acid ester neopentyl glycol diacrylate, dipent of 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, ε-caprolactone adduct of tricyclodecane dimethylol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, Examples thereof include propionic acid / dipentaerythritol triacrylate, hydroxypivalaldehyde-modified dimethylolpropane triacrylate, propionic acid / dipentaerythritol tetraacrylate, and ditrimethylolpropane tetraacrylate.

Examples of the resin oligomer component include acrylic oligomer, ester oligomer, urethane oligomer, ether oligomer and the like. These may be used alone, but when used in combination of two or more, a print receiving layer having different characteristics is obtained.
For example, when an ester-based oligomer is used together with an acrylic-based oligomer, a water-resistant and hard layer can be obtained. In this case, the medium may be warped due to large curing shrinkage, but this can be solved by giving the substrate a warp in the opposite direction in advance. On the other hand, when a urethane oligomer is used together with an acrylic oligomer,
Since the urethane oligomer has a large molecular weight and a small curing shrinkage, the possibility of the substrate warping or the like is reduced. In this case, the formed cured coating film is relatively soft.

Examples of the acrylic oligomer include (meth) acrylic acid, alkyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. A polymer of (meth) acrylate or the above monomer,
Aromatic vinyl compounds such as styrene, α-methylstyrene, (o, m, p) vinylphenol, vinyl carboxylic compounds such as maleic acid, itaconic acid, crotonic acid and fumaric acid, glycidyl (meth) acrylate, allyl glycidyl ether Glycidyl group-containing vinyl compounds such as glycidyl ethyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, aromatic acrylate compounds such as benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) A) acrylate or other substituted alkyl acrylate compound, (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, etc. Riruamido compounds, vinyl acetate,
Copolymers with compounds selected from (meth) acrylonitrile, (meth) acrylic chloride, N- (meth) acryloylmorpholine and the like can be mentioned.

Examples of the ester oligomer include, for example, an ester of acrylic acid and polyester diol composed of a ring-opening polymer of phthalic anhydride and propylene oxide, and a polyester diol composed of 1,6-hexanediol adipic acid and acrylic acid. And an ester of acrylic acid with a triol composed of a reaction product with diethylene glycol trimellitate, and an ester of acrylic acid with a ring-opening polymer of δ-valerolactone.

Examples of the urethane oligomer include a reaction product of a polyurethane composed of hexamethylene diisocyanate and 1,6-hexanediol and 2-hydroxyethyl acrylate, and a polyester diol composed of adipic acid and 1,6-hexanediol. And diisocyanate oligomer obtained by reacting tolylene diisocyanate with 2-hydroxyethyl acrylate.

Examples of the above ether-based oligomer include esters of polypropylene glycol and acrylic acid. In addition, epoxy oligomers, polyarylates, and the like obtained by reacting an acrylate with an epoxy resin can also be used as the resin oligomer component.

Examples of the photopolymerization initiator include benzoin isopropyl ether, benzophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone, 2,4-diethylthioxanthone, methyl o-henzoylbenzoate, 4,4-bisdiethylaminobenzophenone, 2,2-diethoxyacetophen, benzyl, 2-chlorothioxanthone,
Diisopropylthiozanson, 9,10-anthraquinone, bensoin, bensoin 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.

The UV-curable resin composition may further contain a polymerization terminator, a storage stabilizer, a dispersant, an antifoaming agent, a binder resin other than the UV-curable resin, and the like, if necessary.

The print receiving layer in the present invention may be formed by a conventional method, for example, spin coating, dip coating, bar coating, blade coating, air knife coating, roll coating, screen printing, or the like. It is obtained by applying ultraviolet rays after applying the ultraviolet curable resin composition. By the way, usually, an ultraviolet-curing screen printing machine is used for label printing of an optical disk or the like. Processing time is greatly improved.

As a light source for ultraviolet irradiation, a high-pressure mercury lamp,
A metal halide lamp or the like is used. The irradiation energy amount is usually selected from the range of 150 to 2000 mJ / cm ² , preferably 250 to 1000 mJ / cm ² . At this time, since the coating film is cured in a few seconds, the productivity is excellent.However, when a screen printing method is used as a forming method, the surface of the coating film is smoothed and bubbles are released from the coating film instantaneously. It is preferable to add a leveling agent for the purpose of increasing the glossiness of the coating film surface. As a leveling agent,
Silicon and the like are preferred.

The optical recording medium of the present invention is preferably formed by laminating at least a recording layer, a light reflecting layer and a print receiving layer on a transparent substrate, and the print receiving layer forms the outermost layer. . The print receiving layer may also serve as a protective layer, or may have a protective layer separately from the print receiving layer.

When a protective layer is provided separately from the print receiving layer,
The type of the resin of the protective layer is not particularly limited, but is preferably an ultraviolet curable resin as in the case of the print receiving layer. Specifically, those similar to those exemplified above as being usable for the print receiving layer can be mentioned. As the layer forming method, the same method as that for the print receiving layer can be used. The most common. The protective layer may have two or more layers as necessary. Then, a single protective layer may be provided between the protective layer and the print receiving layer for the purpose of imparting abrasion resistance and adjusting the color tone.

As the transparent substrate, for example, a polymer material such as a polycarbonate resin, an acrylic resin, a polystyrene resin, a vinyl chloride resin, an epoxy resin, a polyester resin, and an amorphous polyolefin, and an inorganic material such as glass are used. In particular, polycarbonate resin
It is preferable because of high light transmittance and small optical anisotropy.

On the surface of the transparent substrate, guide grooves, pits and the like (groove information, etc.) indicating recording positions are usually formed on the surface. The groove information or the like is usually given when a substrate is made by injection molding or casting, but may be made by a laser cutting method or a 2P method (Photo-Polymer method).

The recording layer is not particularly limited as long as it can be recorded by irradiation with a laser beam, and may be either a recording layer made of an inorganic substance or a recording layer made of an organic substance.

In the recording layer made of an inorganic substance, for example, Tb.Fe.Co or Dy.F for performing recording by the photothermal magnetic effect is used.
A rare earth transition metal alloy such as e.Co is used. Also,
Chalcogen-based alloys such as Ge.Te and Ge.Sb.Te that change phases may also be used.

For the recording layer made of an organic substance, an organic dye is mainly used. Such organic dyes include macrocyclic azaannulene dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), polymethine dyes (cyanine dyes, merocyanine dyes, stawarylium dyes, etc.), anthraquinone dyes, azurenium dyes, metal-containing dyes Examples include azo dyes and metal-containing indoaniline dyes. In particular, metal-containing azo dyes are preferable because of their excellent durability and light resistance.

The dye-containing recording layer is usually formed by spin coating,
The film is formed by a coating method such as spray coating, dip coating, and roll coating. In this case, the solvent may be a ketone alcohol solvent such as diacetone alcohol or 3-hydroxy-3-methyl-2-butanone, a cellosolve solvent such as methyl cellosolve or ethyl cellosolve, or a perfluoro solvent such as tetrofluoropropanol or octafluoropentanol. Alkyl alcohol solvents, hydroxyethyl solvents such as methyl lactate and methyl isobutyrate are preferably used.

The light reflecting layer is usually made of gold, silver, aluminum or the like. When an organic dye is used for the recording layer, it is particularly preferable to be made of silver. The metal reflection layer is formed by a vapor deposition method, a sputtering method, or an ion plating method. Note that an intermediate layer may be provided between the metal reflective layer and the recording layer for the purpose of improving the adhesion between the layers or for the purpose of increasing the reflectance.

The thickness of the above recording layer is usually from 10 to 5000.
nm, the thickness of the light reflecting layer is usually 50 to 200 nm, the thickness of the print receiving layer is usually 5 to 50 μm, and the thickness of the protective layer is usually 1
〜１０10 μm.

When the thickness of the print receiving layer is less than 5 μm, it is difficult to secure a void volume necessary for absorbing the ink, and ink that cannot be absorbed remains on the surface of the receiving layer, thereby causing image bleeding. There are cases. Conversely, the thickness is 50 μm
If it exceeds 3, the absorption and permeation of the ink proceeds to the inside of the layer, the color developability of the ink on the surface of the receiving layer decreases, and the sharpness of the image decreases. Furthermore, the ultraviolet light transmission is inferior during ultraviolet irradiation, and there is a possibility that the inside of the layer may be insufficiently cured.

In the optical recording medium of the present invention, fine particles such as titanium oxide are contained in the protective layer laminated on the metal reflection film in order to improve the printing characteristics of the print when full color printing is performed on the outermost layer. It may be whitened.

[0053]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

Example 1 Injection molded polycarbonate resin substrate (120 mm in diameter) with a depth of 1600 mm and a width of 0.45 μm.
A solution of the metal-containing azo dye is dropped thereon, applied by spin coating at a rotation speed of 500 rpm, and dried at 90 ° C. for 30 minutes to form a recording layer.

Next, a silver film having a thickness of 800 ° (80 nm) is formed on the recording layer by sputtering to form a reflection layer. Then, after UV-curable resin is spin-coated on the entire surface of the reflective layer, it is cured by irradiating UV rays to form a 5 μm protective layer. Further, an ultraviolet curable resin composition having the composition shown in the following table is applied to the entire surface of the protective layer by screen printing, and then cured by irradiating ultraviolet rays to form a print receiving layer having a thickness of 20 μm.

[0056]

[Table 1]

Printing was performed on the print receiving layer of the optical recording medium obtained above using "CD-ColorPrinter" manufactured by Fargo Co., Ltd., and the absorption of printing ink, the water resistance of the image, and the water resistance of the receiving layer were determined according to the following methods. Measure and evaluate.

(1) Printing ink absorbency: Solid printing as shown in FIG. 1 is performed with two different colors A and B selected from four colors of cyan, magenta, yellow and black (the combination of colors A and B is 12 And the degree of bleeding at the boundary between the two colors is visually evaluated. When there was no bleeding / color mixing between different colors, it was evaluated as 、, when bleeding / color mixing between different colors was slightly observed, and as Δ, when bleeding / color mixing between different colors was severe.

(2) Water resistance of image: cyan, magenta,
Perform solid printing as shown in Fig. 1 with two different colors A and B selected from four colors of yellow and black (12 combinations of colors A and B), and after 1 hour, drop about 1 cc of water on the image part I do. After leaving it at room temperature for 1 minute, wipe it with a clean room wiper (Bencott manufactured by Asahi Kasei Corporation)
The elution state of the ink in the image portion is visually evaluated. If the ink is not eluted and there is no color change, ○, if the ink is eluted and the color of the image at the portion where the water is dropped becomes slightly lighter, △, the ink is eluted and the image at the portion where the water is dropped is When the color became considerably light, it was evaluated as x.

(3) Water resistance of the receiving layer: After storing the optical recording medium provided with the print receiving layer in a 25 ° C./80% RH environment for 3 days, 5 minutes later, a surface property test manufactured by Shinto Kagaku Co., Ltd. A pencil hardness measurement is performed using an instrument Tribogear 14S type to measure the strength of the receiving layer. When the pencil hardness was H or more, it was evaluated as ○, when it was from F to B, it was evaluated as Δ, and when it was 2B or less, it was evaluated as ×.

[0061]

According to the present invention described above, it is possible to provide a printable optical recording medium which is excellent in printing characteristics, storage stability and printing water resistance of a full-color liquid ink jet printer.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an example of solid printing used for evaluation of printing ink absorption and water resistance of an image.

[Explanation of symbols]

 1: Color A 2: Color B 3: Boundary part

Claims (5)

[Claims] 1. An optical recording medium having a print receiving layer as an outermost layer of a medium, wherein the print receiving layer is made of an ultraviolet curable resin composition containing fine particles having an average particle diameter of 200 nm or less and a cationic resin. . 2. The optical recording medium according to claim 1, wherein the content of the fine particles is at least 30% by weight and less than 100% by weight based on the ultraviolet-curable resin composition. 3. The optical recording medium according to claim 1, wherein the fine particles have an average particle size of 1 to 100 nm. 4. The optical recording medium according to claim 1, wherein the fine particles are silica. 5. An optical recording medium in which at least a recording layer, a light reflecting layer and a print receiving layer are sequentially laminated on a transparent substrate, wherein the print receiving layer also serves as a protective layer, or 2. A protective layer is provided between the reflective layer and the reflective layer.
5. The optical recording medium according to any one of items 1 to 4,