JP2006102993A - Method for manufacturing information medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information medium almost free from warpage with a printable layer allowing a high quality image to be printed. <P>SOLUTION: This method for manufacturing the information medium has a process to form the printable layer by applying a coating liquid for an ink acceptance layer containing at least a fine particle, a binding agent and a crosslinking agent to the surface of an undercoat layer. The surface tension of the coating liquid for the ink acceptance layer is not more than 5×10<SP>-2</SP>N/m. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an information medium having a printable layer capable of printing characters and photographs.

As information media standards widely accepted in the market, there are CD (compact disc) and DVD (digital versatile disc).
CDs include a read-only CD-ROM, a write-once CD-R that can record information only once, and a rewritable CD-RW that can rewrite information any number of times.
In a CD-ROM, for example, pit rows are formed on a transparent substrate having a diameter of 120 mm and a thickness of 1.2 mm with a track pitch of 1.6 μm, a recording capacity of about 650 Mbytes, and a linear velocity of 1.2. Information is reproduced by irradiating with a laser beam having a wavelength of 770 to 790 nm, which is constant at ˜1.4 m / s.

On the other hand, DVDs include DVD-ROM, DVD-R, and DVD-RW as in the case of CD.
The DVD-ROM has a recording density of about 6 to 8 times that of a CD, and has a configuration in which two substrates having a thickness of about 0.6 mm are bonded together, and pits are formed at a track pitch of 0.74 μm. Information is reproduced by irradiating a laser beam having a wavelength of 635 to 650 nm with a linear velocity of about 3.5 m / s.

In recent years, in such CDs and DVDs, an information medium has been developed in which a printable layer is formed on the surface opposite to the information reproduction surface so that an image can be printed with an ink jet printer (for example, Patent Documents). 1). As a material for the printable layer of such an information medium, an ultraviolet curable resin is generally used. However, a printable layer made of an ultraviolet curable resin cannot obtain a high image quality as compared with an inkjet recording sheet. was there.
In addition, when the printable layer made of an ultraviolet curable resin is formed thick, it is necessary to increase the energy supplied during the ultraviolet curing, and as a result, the warp and runout of the disk may become a problem. For this reason, the printable layer needs to have a thin layer thickness. As a result, a sufficient absorption capacity for absorbing all ink droplets cannot be obtained, and the bleed stability of the printed image has been a problem.
Further, the ultraviolet curable resin has skin irritation, and there is a problem in the safety of the material. Furthermore, the ultraviolet curable resin needs to be stored in a dark room at room temperature, has a short life, has an unpleasant odor, and has a problem in handling.

Therefore, the present applicant has proposed an information medium having a printable layer including a porous ink-receiving layer (Japanese Patent Application No. 2003-67750) in order to solve the above-described problem of a printable layer made of an ultraviolet curable resin. This printable layer has advantages such as high handling safety and high image quality comparable to an inkjet recording sheet. The ink receiving layer in such a printable layer needs to have a certain thickness or more in order to secure a sufficient ink receiving capability. That is, if the ink receiving layer is too thin, the void volume in the layer is small, so that the ink cannot be absorbed sufficiently and blurring occurs immediately after printing. Although it depends on the kind of fine particles, the thickness of the porous ink receiving layer is generally required to be 20 μm or more in the case of an ink jet recording sheet.
However, in the case of an optical disk (information medium), if the ink receiving layer is thickened, the disk may be warped due to the internal stress of the layer. Therefore, in order to solve the problem of the warp of the disk while ensuring a certain layer thickness, some measures are necessary.
JP 2002-245671 A

An object of the present invention is to solve the conventional problems and achieve the following objects. That is,
An object of the present invention is to provide a method of manufacturing an information medium that has a printable layer that can print with high image quality with little blurring and less warpage.

Means for solving the above problems are as follows. That is,
<1> A method for producing a disc-shaped information medium, which includes a step of applying a coating solution for an ink receiving layer containing at least fine particles, a binder, and a crosslinking agent on a base layer to form a printable layer. The method for producing an information medium is characterized in that the surface tension of the ink receiving layer coating liquid is 5 × 10 ⁻² N / m or less.

<2> The fine particles are at least one selected from gas phase method silica, pseudoboehmite, and aluminum oxide, the binder is polyvinyl alcohol, the crosslinking agent is a boron compound, and The method for producing an information medium according to <1>, wherein the coating liquid for the ink receiving layer further contains a mordant.

<3> The ink receiving layer coating liquid is applied by an extrusion die coater so that the flow rate from the discharge port increases from the inner periphery toward the outer periphery according to the linear velocity. > Or <2>.

  According to the present invention, it is possible to provide an information medium that has a printable layer that can be printed with high image quality with little blurring, and a method for manufacturing the same.

The method for producing an information medium of the present invention is a disc-shaped information having a step of forming a printable layer by applying an ink receiving layer coating solution containing at least fine particles, a binder, and a crosslinking agent on an underlayer. A method for producing a medium, wherein the surface tension of the coating liquid for an ink receiving layer is 5 × 10 ⁻² N / m or less. Hereinafter, an information medium manufactured by the information medium manufacturing method of the present invention will be described first.

<Information media>
The information medium manufactured by the manufacturing method of the present invention can be applied to a magnetic medium, an optical medium, a semiconductor medium, and the like. The form may be a disk shape or a cartridge storage type, and in the case of a cartridge storage type, it is removable. Preferably there is. In particular, an optical information recording medium (optical disk) is preferable as a disk-shaped medium.
In the case of an optical disc, it may be any one such as a CD, a DVD, an optical disc that is recorded and reproduced with a blue-violet laser.
In the case of a medium for recording with a blue-violet laser, there are a bonded type such as a DVD, and a type in which a recording layer and a cover layer are formed on a 1.1 mm substrate, and laser light is incident from the cover layer side. Either may be sufficient.
The place where the printable layer is formed is basically on the side opposite to the surface on which the laser light is incident, but the printable layer can be formed on the side where the laser light is incident as long as it is an area other than the incident area.
The information medium according to the present invention may be a ROM type, a rewritable type, or a write-once type, but the write-once type is particularly preferable.

  Hereinafter, the substrate and each layer used in the information medium according to the present invention will be described. Note that the layer configuration, materials, and the like are merely examples, and the present invention is not limited to these.

<Printable layer>
The information medium according to the present invention has a printable layer including at least a base layer and an ink receiving layer. Hereinafter, each layer of the printable layer will be described.

[Ink receiving layer]
The ink receiving layer in the present invention preferably has, for example, a configuration having at least fine particles, a binder, and a crosslinking agent, and may contain various additives.

In addition, the ink receiving layer in the present invention has a variety of known surfactants for the purpose of adjusting surface tension, coating suitability and surface quality, and ion conductivity for the purpose of suppressing surface frictional charge and peeling charge. Known surfactants having an antioxidant, an ultraviolet absorber for the purpose of enhancing photofading, and a sulfur-containing compound for the purpose of enhancing ozone fading resistance may be used in a range not impairing the effects of the present invention. Good.
Hereinafter, each component contained in the ink receiving layer will be described.

(Fine particles)
As described above, the ink receiving layer in the present invention contains fine particles. Examples of the fine particles include vapor phase silica, pseudoboehmite, aluminum oxide, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, boehmite, and the like. Among these, gas phase method silica, pseudoboehmite, and aluminum oxide are preferable.

-Gas phase method silica-
Silica fine particles are generally roughly classified into wet method particles and dry method (gas phase method) particles according to the production method. In the above wet method, a method is mainly used in which activated silica is produced by acid decomposition of a silicate, and this is appropriately polymerized and agglomerated and precipitated to obtain hydrous silica. On the other hand, the gas phase method is a method by high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized with air. The method of obtaining anhydrous silica by the (arc method) is the mainstream, and “gas phase method silica” means anhydrous silica fine particles obtained by the gas phase method.

The above-mentioned gas phase method silica is different from the above-mentioned hydrous silica in the density of silanol groups on the surface, the presence or absence of vacancies, etc., and shows different properties, but is suitable for forming a three-dimensional structure with high porosity. . The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is large at 5 to 8 / nm ² , and the silica fine particles tend to aggregate closely (aggregate). In the case of the method silica, the density of silanol groups on the surface of the fine particles is 2 to 3 / nm ² , so that it is sparse soft agglomeration (flocculate), resulting in a structure with a high porosity. Is done.

  The above-mentioned vapor phase silica has a particularly large specific surface area, so the ink absorption and retention efficiency is high, and the refractive index is low, so that the ink receiving layer can be transparent if dispersed to an appropriate particle size. And high color density and good color developability can be obtained.

  The average primary particle diameter of the vapor phase silica is preferably 30 nm or less, more preferably 20 nm or less, particularly preferably 10 nm or less, and most preferably 3 to 10 nm. Since the vapor phase silica is easily adhered to each other by hydrogen bonding with a silanol group, a structure having a large porosity can be formed when the average primary particle diameter is 30 nm or less, and ink absorption characteristics are effectively improved. Can be improved.

  Also, other inorganic pigment fine particles such as hydrous silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, boehmite, pseudoboehmite, etc. You may use together. When the other inorganic pigment fine particles and the vapor phase silica are used in combination, the content of the vapor phase silica in the total inorganic pigment fine particles is preferably 50% by mass or more, and more preferably 70% by mass or more.

-Pseudo boehmite-
Pseudoboehmite is represented by Al ₂ O ₃ .xH ₂ O (1 <x <2). In general, the crystal is a layered compound in which a (020) plane forms a huge plane, and its lattice constant d is 0. .67 nm. Here, the pseudo boehmite has a structure containing excess water between (020) plane layers. Pseudoboehmite absorbs and fixes ink well and can improve ink absorbency and aging blur.
In addition, since a smooth layer can be easily obtained, it is preferable to use sol-like pseudoboehmite (pseudoboehmite sol) as a raw material.

The primary average particle size of pseudoboehmite is preferably 50 nm or less, more preferably 30 nm or less, and particularly preferably in the range of 20 to 3 nm. When the average primary particle size of the pseudo boehmite is within the above range, a structure having a large porosity can be formed, and ink absorbability of the ink receiving layer can be further improved. In addition, the said average primary particle diameter can be measured using an electron microscope, for example. Moreover, as a BET specific surface area of pseudo boehmite, 40-500 m < ² > is preferable and 200-500 m < ² > is still more preferable.

  Furthermore, the aspect ratio of the pseudo boehmite is preferably 3 to 10. About the pore structure of pseudo boehmite, the average pore radius is preferably 1 to 30 nm, and more preferably 2 to 15 nm. The pore volume is preferably 0.3 to 2.0 ml / g (cc / g), more preferably 0.5 to 1.5 ml / g (cc / g). Here, the pore radius and pore volume are measured by a nitrogen adsorption / desorption method, and can be measured by, for example, a gas adsorption / desorption analyzer (for example, trade name “Omni Soap 369” manufactured by Coulter). .

Pseudoboehmite is preferably used by being dispersed in an aqueous solvent. The pseudo boehmite content in the dispersion when used in a dispersed state is preferably 60% by mass or less, more preferably 5 to 60% by mass, and particularly preferably 10 to 50% by mass.
Pseudoboehmite can be dispersed particularly effectively within the above-mentioned range. For example, it effectively suppresses thickening or gelation caused by shortening the interparticle distance between pseudoboehmite during dispersion. Can do.

The content ratio (S: A) of the pseudoboehmite (A) and the vapor phase silica (S) used in combination with the pseudoboehmite (A) is preferably in the range of 95: 5 to 5:95, and 80:20 to 20:80. A range is more preferable, and a range of 70:30 to 30:70 is particularly preferable.
When the vapor phase method silica and pseudoboehmite are used in combination within the range of the content ratio, it is possible to effectively prevent aging blur of all the inks of a plurality of colors without depending on the hue, even in the case of forming a multicolor image. A high-resolution and vivid image can be formed and maintained.

-Aluminum oxide-
Examples of the aluminum oxide in the present invention include anhydrous alumina such as α-alumina, δ-alumina, θ-alumina, and χ-alumina, and active aluminum oxide. Among these, preferable alumina fine particles are δ-alumina, and from the viewpoint of the production method, alumina fine particles produced by a gas phase method, that is, in the presence of water generated during an oxyhydrogen reaction, and Vapor phase alumina fine particles obtained by hydrolyzing gaseous metal chloride at a temperature characteristic of such a reaction are preferred because of their large specific surface area.

  As the form of the aluminum oxide, for example, fine particles having a predetermined particle diameter, fine particles, fine particles, powder, fine powder, fine powder and the like can be adopted, and the average primary particle diameter is 200 nm or less. Preferably, it is 5-100 nm, more preferably 5-20 nm. When the average primary particle diameter of the alumina fine particles is within the above range, a structure having a large porosity can be formed, and ink absorbability of the ink receiving layer can be further improved. In addition, the said average primary particle diameter can be measured using an electron microscope, for example.

  In the present invention, aluminum oxide is preferably used by being dispersed in a dispersion. The content of aluminum oxide in the dispersion is preferably 60% by mass or less, more preferably 5 to 60% by mass, and particularly preferably 10 to 50% by mass. When the content of aluminum oxide is within the above range, aluminum oxide can be more effectively dispersed. When the content of aluminum oxide in the dispersion is at most 60% by mass, for example, thickening or gelation caused by shortening the inter-particle distance between aluminum oxide fine particles in the dispersion, etc. It can be effectively suppressed. In addition, a cationic polymer having primary to tertiary amino groups and salts thereof, and a quaternary ammonium base may be added to the dispersion as an aggregation inhibitor. The addition amount of the aggregation inhibitor is preferably 1 to 10% by mass, more preferably 1 to 5% by mass with respect to the aluminum oxide fine particles. If the addition amount is less than 1% by mass, the dispersibility may be inferior. If the addition amount exceeds 10% by mass, the color density may decrease when printing on the ink receiving layer, which is not preferable.

  The solid content in the ink-receiving layer of aluminum oxide is preferably 50% by mass or more, and more preferably 60% by mass or more. When the content exceeds 60% by mass, it is possible to form a more favorable porous structure, and an ink receiving layer having sufficient ink absorbability can be obtained, which is preferable. Here, the solid content in the ink-receiving layer of aluminum oxide is a content calculated based on components other than water in the composition constituting the ink-receiving layer.

In the present invention, aluminum oxide and other fine particles may be used in combination. When the other fine particles and the aluminum oxide are used in combination, the content of aluminum oxide in the present invention in all fine particles is preferably 30% by mass or more, and more preferably 50% by mass or more.
The other fine particles may be either organic fine particles or inorganic fine particles, but inorganic fine particles are preferable from the viewpoint of ink absorbability and image stability.

(Binder)
As described above, in the present invention, the ink receiving layer contains a binder. As the binder, a water-soluble resin is preferable.

Examples of the water-soluble resin include, for example, a polyvinyl alcohol resin that is a resin having a hydroxyl group as a hydrophilic structural unit [for example, polyvinyl alcohol (PVA), acetoacetyl-modified PVA, cation-modified PVA, anion-modified PVA, silanol-modified PVA, Polyvinyl acetal, etc.], cellulose resins [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, etc.], chitins , Chitosans, starch, resins having an ether bond [eg, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene Recall (PEG), poly ether (PVE)] and resins having carbamoyl groups [e.g., polyacrylamide (PAAM), polyvinyl pyrrolidone (PVP), polyacrylic acid hydrazide, etc.] and the like.
Further, as the water-soluble resin, polyacrylates having a carboxy group as a dissociable group, maleic acid resins, alginates, gelatins, and the like can also be used.

Among these, polyvinyl alcohol (PVA) resin is particularly preferable. Examples of the polyvinyl alcohol include Japanese Patent Publication No. 4-52786, Japanese Patent Publication No. 5-67432, Japanese Patent Publication No. 7-29479, Japanese Patent No. 2537827, Japanese Patent Publication No. 7-57553, Japanese Patent No. 2502998, and Japanese Patent No. 3053231. JP-A-63-176173, JP-A-2604367, JP-A-7-276787, JP-A-9-207425, JP-A-11-58941, JP-A-2000-135858, JP-A-2001-205924, JP 2001-287444, JP 62-278080, JP 9-39373, JP 2750433, JP 2000-18801, JP 2001-213045, JP 2001-328345, JP 8 -324105, JP-A-11-348417, etc. It can be.
Examples of water-soluble resins other than polyvinyl alcohol resins include the compounds described in paragraph numbers [0011] to [0014] of JP-A No. 11-165461.

  These water-soluble resins may be used alone or in combination of two or more. In the present invention, the content of the water-soluble resin is preferably 9 to 40% by mass, and more preferably 12 to 33% by mass with respect to the total solid content of the ink receiving layer.

  In addition, the polyvinyl alcohol resin may be used in combination with the other water-soluble resin. When the other water-soluble resin and the polyvinyl alcohol-based resin are used in combination, the content of the polyvinyl alcohol-based resin in the total water-soluble resin is preferably 50% by mass or more, and more preferably 70% by mass or more.

The polyvinyl alcohol has a hydroxyl group in the structural unit. The hydroxyl group and a silanol group on the surface of the silica fine particle form a hydrogen bond to form a three-dimensional network structure in which the secondary particle of the silica fine particle is a chain unit. Make it easier. It is considered that an ink receiving layer having a porous structure with a high porosity can be formed by forming the three-dimensional network structure.
In ink-jet recording, the porous ink-receiving layer obtained as described above can absorb ink rapidly by capillary action, and can form dots with good roundness without ink blurring.

  From the viewpoint of transparency, polyvinyl alcohol having a saponification degree of 70 to 99% is more preferable, and polyvinyl alcohol having a saponification degree of 80 to 99% is particularly preferable.

(Mass ratio of fine particles to binder)
The mass content ratio [PB ratio (x / y)] of the fine particles (x) and the binder (y) in the ink receiving layer greatly affects the film structure and film strength of the ink receiving layer. That is, when the mass content ratio [PB ratio] increases, the porosity, pore volume, and surface area (per unit mass) increase, but the density and strength tend to decrease.

  In the ink receiving layer according to the present invention, the mass content ratio [PB ratio (x / y)] prevents a decrease in film strength and cracks during drying caused by the PB ratio being too large, and When the PB ratio is too small, the voids are easily blocked by the resin, and from the viewpoint of preventing the ink absorbency from being lowered due to the decrease in the void ratio, 1.5 / 1 to 10/1 is preferable.

  Since stress may be applied to the information medium when passing through the conveyance system of the ink jet recording printer, the ink receiving layer preferably has sufficient film strength. Further, when cutting into a sheet shape, it is preferable that the ink receiving layer has sufficient film strength in order to prevent the ink receiving layer from cracking or peeling off. In consideration of these cases, the PB ratio (x / y) is more preferably 5/1 or less, while it is 2: 1 or more from the viewpoint of ensuring high-speed ink absorbability in an inkjet recording printer. Is more preferable.

Specifically, for example, a gas phase method silica fine particle having an average primary particle diameter of 20 nm or less and a water-soluble resin are completely dispersed in an aqueous solution at a PB ratio (x / y) of 2/1 to 5/1. When the liquid is coated on a support and the coating layer is dried, a three-dimensional network structure is formed in which secondary particles of silica fine particles are network chains, the average pore diameter is 30 nm or less, and the porosity is 50 to 80. %, A translucent porous film having a pore specific volume of 0.5 ml / g or more and a specific surface area of 100 m ² / g or more can be easily formed.

(Crosslinking agent)
The ink receiving layer includes a cross-linking agent that can cross-link the binder. By containing a crosslinking agent, it can be set as the porous layer hardened | cured by the crosslinking reaction of a crosslinking agent and a binder.

Boron compounds are preferred for crosslinking the water-soluble resin, particularly polyvinyl alcohol. Examples of the boron compound include borax, boric acid, borate (for example, orthoborate, InBO ₃ , ScBO ₃ , YBO ₃ , LaBO ₃ , Mg ₃ (BO ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , two Borate (eg, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na _{2 B 4 O 7 · 10H 2} O), can be mentioned five borate _{(e.g., KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O 5) or the like. Among them, Of these, borax, boric acid, and borate are preferable, and boric acid is particularly preferable in that a crosslinking reaction can be promptly caused.

Compounds other than the above boron compounds can also be used as a crosslinking agent for the water-soluble resin. For example,
Aldehyde compounds such as formaldehyde, glyoxal, succinaldehyde, glutaraldehyde, dialdehyde starch, dialdehyde derivatives of plant gum; ketones such as diacetyl, 1,2-cyclopentanedione, 3-hexene-2,5-dione Compounds; active halogen compounds such as bis (2-chloroethyl) urea, bis (2-chloroethyl) sulfone, 2,4-dichloro-6-hydroxy-s-triazine sodium salt; divinylsulfone, 1,3-bis (vinyl) Sulfonyl) -2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide), divinyl ketone, 1,3-bis (acryloyl) urea, 1,3,5-triacryloyl-hexahydro-s-triazine, etc. Active vinyl compounds; dimethylol urea, methylo N-methylol compounds such as rudimethylhydantoin; melamine compounds such as trimethylol melamine, alkylated methylol melamine, melamine, benzoguanamine, melamine resin; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, diglycerin Epoxy compounds such as polyglycidyl ether, spiroglycol diglycidyl ether, and polyglycidyl ether of phenol resin;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate and xylylene diisocyanate; aziridine compounds described in U.S. Pat. Nos. 3,017,280 and 2,983611; and U.S. Pat. No. 3,100,704 Carbodiimide compounds; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxydioxane and the like Dioxane compounds; metal-containing compounds such as titanium lactate, aluminum sulfate, chromium alum, potash alum, zirconyl acetate and chromium acetate; polyamine compounds such as tetraethylenepentamine; hydrazide compounds such as adipic acid dihydrazide; 2 oxazoline groups Including more than Low molecule or polymer having: anhydride of polyvalent acid, acid described in US Pat. No. 2,725,294, US Pat. No. 2,725,295, US Pat. No. 2,726,162, US Pat. No. 3,834,902, etc. Examples include chloride and bissulfonate compounds; active ester compounds described in US Pat. No. 3,542,558, US Pat. No. 3,251972, and the like.
Said crosslinking agent may be used individually by 1 type, and can also be used in combination of 2 or more type.

When gelatin is used in combination with the polyvinyl alcohol, the following compounds, which are known as gelatin hardeners, can be used in combination with a boron compound as a crosslinking agent.
For example, aldehyde compounds such as formaldehyde, glyoxal and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5- Active halogen compounds such as triazine and 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide) ), Active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate; Aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983611; Carboximide compounds described in US Pat. No. 3,100,704; Glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane compounds such as dioxane; chromium alum, potash alum, zirconium sulfate, chromium acetate and the like. In this case, when using the said boron compound and another crosslinking agent together, 50 mass% or more is preferable and, as for content of the boron compound in all the crosslinking agents, 70 mass% or more is more preferable.
In addition, the said boron compound may be single 1 type, or may combine 2 or more types.

When the boron compound is applied, the solution is prepared by dissolving the boron compound in water and / or an organic solvent.
As a density | concentration of the boron compound in the said boron compound solution, 0.05-10 mass% is preferable with respect to the mass of a boron compound solution, and 0.1-7 mass% is especially preferable.
As a solvent constituting the boron compound solution, water is generally used, and an aqueous mixed solvent containing an organic solvent miscible with water may be used.
As said organic solvent, if a boron compound melt | dissolves, it can be used arbitrarily, For example, alcohol, such as methanol, ethanol, isopropyl alcohol, and glycerol; Ketone, such as acetone and methyl ethyl ketone; Methyl acetate, ethyl acetate, etc. An aromatic solvent such as toluene; an ether such as tetrahydrofuran; and a halogenated carbon-based solvent such as dichloromethane.

(mordant)
In the present invention, a mordant is preferably contained in the ink receiving layer in order to further improve the water resistance and aging resistance of the formed image.
As the mordant, a cationic polymer (cationic mordant) is preferable. When the mordant is present in the ink receiving layer, it interacts with a liquid ink having an anionic dye as a colorant to stabilize the colorant. Water resistance and aging blur can be improved.

  However, when this is directly added to the coating solution for forming the ink receiving layer, there is a concern that aggregation may occur with the vapor phase silica having an anionic charge. If it is used, there is no need to worry about the aggregation of inorganic pigment fine particles. Therefore, in the present invention, it is preferable to use by containing in a solution (for example, a crosslinking agent solution) different from the above-mentioned vapor-phase process silica.

As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group is preferably used, but a cationic non-polymer mordant may also be used. it can.
Examples of the polymer mordant include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base (mordant monomer), and the mordant monomer and other monomers (hereinafter, What is obtained as a copolymer or condensation polymer with "non-mordant monomer") is preferred. These polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.

  Examples of the monomer (mordant monomer) include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N , N-dimethyl-N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-N -P-vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-die Ru-N-benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-N -P-vinylbenzylammonium chloride,

Trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl-m-vinyl Benzylammonium acetate, N, N, N-triethyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N, N-triethyl-N-2- (3-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride Tate,

N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N- Methyl chloride, ethyl chloride, methyl bromide of dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide , Quaternized products of ethyl bromide, methyl iodide or ethyl iodide, or sulfonates, alkyl sulfonates, acetates or alkyl carboxylates substituted for their anions.

  Specifically, for example, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, triethyl-2- (acryloyloxy) ) Ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl-2- (methacryloylamino) ethyl Ammonium chloride, trimethyl-2- (acryloylamino) ethylammonium chloride, triethyl-2- ( Acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) propylammonium chloride, triethyl-3- (acryloyl) Amino) propylammonium chloride,

N, N-dimethyl-N-ethyl-2- (methacryloyloxy) ethylammonium chloride, N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N, N-dimethyl-N-ethyl- 3- (acryloylamino) propylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, trimethyl-3- And (acryloylamino) propylammonium acetate.
In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole.

The non-mordant monomer does not include a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and does not show an interaction with a dye in an inkjet ink. Or the monomer which interaction is substantially small is said.
Examples of the non-mordant monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylate; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; Aralkyl esters such as (meth) benzyl acrylate; Aromatic vinyls such as styrene, vinyl toluene and α-methylstyrene; Vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatic acid; Allyl esters such as allyl acetate Halogen-containing monomers such as vinylidene chloride and vinyl chloride; vinyl cyanide such as (meth) acrylonitrile; olefins such as ethylene and propylene; and the like.

The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl moiety, for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Propyl acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, Examples include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like.
Of these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and hydroxyethyl methacrylate are preferable.
The non-mordant monomers can also be used singly or in combination of two or more.

  Further, as a polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethylenimine, polyallylamine, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate Dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine and the like can also be mentioned as preferable examples.

  The molecular weight of the polymer mordant is preferably 1000 to 200000 in terms of weight average molecular weight, and more preferably 3000 to 60000 in terms of weight average molecular weight. When the molecular weight is in the range of 1,000 to 200,000, water resistance does not become insufficient, and it is possible to prevent the viscosity from becoming excessively high and handling suitability from being lowered.

  As the cationic non-polymer mordant, for example, water-soluble metal salts such as aluminum sulfate, aluminum chloride, polyaluminum chloride, and magnesium chloride are preferable.

(Other ingredients)
The ink receiving layer may contain the following components as needed.
For the purpose of suppressing the deterioration of the coloring material, various ultraviolet absorbers, antioxidants, anti-fading agents such as singlet oxygen quenchers may be included.
Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, benzotriazolylphenol derivatives, and the like. For example, α-cyano-phenyl cinnamate butyl, o-benzotriazole phenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-2,4-di-t-butylphenol, o-benzotriazole-2,4 -Di-t-octylphenol etc. are mentioned. A hindered phenol compound can also be used as an ultraviolet absorber, and specifically, a phenol derivative in which at least one of 2-position or 6-position is substituted with a branched alkyl group is preferable.

  Moreover, a benzotriazole type ultraviolet absorber, a salicylic acid type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, an oxalic acid anilide type ultraviolet absorber, etc. can be used. For example, JP-A-47-10537, 58-111942, 58-21284, 59-19945, 59-46646, 59-109055, 63-53544. No. 36, Japanese Patent Publication No. 36-10466, No. 42-26187, No. 48-30492, No. 48-31255, No. 48-41572, No. 48-54965, No. 50-10726. No. 2,719,086, US Pat. No. 3,707,375, US Pat. No. 3,754,919, US Pat. No. 4,220,711, and the like. .

  A fluorescent brightening agent can also be used as an ultraviolet absorber, and examples thereof include a coumarin fluorescent brightening agent. Specifically, it is described in Japanese Patent Publication Nos. 45-4699 and 54-5324.

  Examples of the antioxidant include European Patent Publication No. 223739, Publication No. 309401, Publication No. 309402, Publication No. 310551, Publication No. 310552, Publication No. 4594416, Publication of German Patent No. 3435443, JP-A-54-48535, JP-A-60-107384, JP-A-60-107383, JP-A-60-125470, JP-A-60-125471, JP-A-60-125472, JP-A-60-287485. 60-287486, 60-287487, 60-287488, 61-160287, 61-185483, 61-2111079, 62-146678, 62-146680, 62-146679, 62-282885, JP same 62-262047, JP-same 63-051174, JP-same 63-89877, JP-same 63-88380, JP-same 66-88381, JP-same 63-113536, JP-

JP-A-63-163351, JP-A-63-203372, JP-A-63-224989, JP-A-63-251282, JP-A-63-267594, JP-A-63-182484, JP-A-1-239282, JP-A-2-262654, JP-A-2-71262, JP-A-3-121449, JP-A-4-29185, JP-A-4-291684, JP-A-5-61166, JP-A-5-119449, 5-188687, 5-188686, 5-110490, 5-110437, 5-170361, JP 48-43295, 48-33212, Examples thereof include those described in U.S. Pat. Nos. 4,814,262 and 4,980,275.

  Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2-dihydroquinoline 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2,3 4, -tetrahydroquinoline, nickel cyclohexane acid, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2-methyl-4-methoxy-diphenylamine, Examples include 1-methyl-2-phenylindole.

The anti-fading agent may be used alone or in combination of two or more. This anti-fading agent may be water-solubilized, dispersed, emulsified, or included in microcapsules.
The addition amount of the anti-fading agent is preferably 0.01 to 10% by mass of the ink receiving layer coating solution.

In addition, for the purpose of improving the dispersibility of the inorganic pigment fine particles, various inorganic salts, pH adjusting agents, and the like may contain acids and alkalis.
Further, for the purpose of suppressing surface frictional charge and peeling charge, the metal oxide fine particles having electronic conductivity may contain various matting agents for the purpose of reducing the surface frictional characteristics.

[Underlayer]
When a base layer having high opacity is provided, it has a diffusibility close to that of paper and image quality is improved. In particular, when a white underlayer is provided, color reproducibility can be improved. If the base layer has a high glossiness, it will look like a glossy photo, and if it has a high matteness, it will look like a matte photo. When the underlayer uses various colors, images with various impressions can be formed. In the case of a fluorescent underlayer, fluorescent image quality can be obtained.

  The layer thickness of the underlayer is preferably from 0.1 to 100 μm, more preferably from 1 to 50 μm, and most preferably from 3 to 20 μm.

[Middle layer]
In the information medium according to the present invention, an intermediate layer may be provided between the ink receiving layer and the base layer. In this case, the adhesion between the ink receiving layer and the undercoat layer can be improved, or the warp of the entire information medium can be adjusted.

  The thickness of the intermediate layer is preferably 0.1 to 100 μm, more preferably 1 to 50 μm, and most preferably 3 to 20 μm.

[Surface layer]
The information medium according to the present invention may have a surface layer on the ink receiving layer. By the surface layer, the surface strength can be further improved, and the storability of the print can be improved. The surface layer needs to have a property of accepting ink or transmitting it quickly.

  The layer thickness of the surface layer is preferably 0.01 to 100 μm, more preferably 0.1 to 10 μm, and most preferably 0.5 to 5 μm.

[substrate]
As the substrate, various materials used as substrate materials for conventional optical recording media can be arbitrarily selected and used.
Specifically, glass; acrylic resin such as polycarbonate and polymethyl methacrylate; vinyl chloride resin such as polyvinyl chloride and vinyl chloride copolymer; epoxy resin; amorphous polyolefin; polyester; metal such as aluminum; These may be used together if desired.
Among the above materials, amorphous polyolefin and polycarbonate are preferable, and polycarbonate is particularly preferable from the viewpoints of moisture resistance, dimensional stability, and low cost. Further, the thickness of the substrate is preferably 0.5 to 1.2 mm, and more preferably 0.6 to 1.1 mm.

The substrate is formed with unevenness (pregroove) representing information such as a guide groove for tracking or an address signal.
In the case of a medium for recording with a blue-violet laser, the track pitch of the pregroove is preferably in the range of 200 to 800 nm, more preferably 200 to 500 nm, and further preferably 200 to 400 nm.
The depth of the pregroove (groove depth) is preferably in the range of 10 to 180 nm, more preferably 20 to 150 nm.
Furthermore, the half width of the pregroove is preferably in the range of 200 to 400 nm, more preferably 230 to 380 nm, and even more preferably 250 to 350 nm.

In the case of DVD-R or DVD-RW, the track pitch of the pregroove is preferably in the range of 300 to 900 nm, more preferably 350 to 850 nm, and still more preferably 400 to 800 nm.
The depth of the pregroove (groove depth) is preferably in the range of 100 to 160 nm, more preferably 120 to 150 nm, and still more preferably 130 to 140 nm.
Furthermore, the half width of the pregroove is preferably in the range of 200 to 400 nm, more preferably 230 to 380 nm, and even more preferably 250 to 350 nm.

In the case of CD-R or CD-RW, the pregroove track pitch is preferably in the range of 1.2 to 2.0 μm, more preferably in the range of 1.4 to 1.8 μm, More preferably, it is 1.65 μm.
The depth of the pregroove (groove depth) is preferably in the range of 100 to 250 nm, more preferably 150 to 230 nm, and even more preferably 170 to 210 nm.
The half width of the pregroove is preferably in the range of 400 to 650 nm, more preferably 480 to 600 nm, and further preferably 500 to 580 nm.

[Recording layer]
In the write-once type, the dye used in the recording layer is not particularly limited, but examples of usable dyes include cyanine dyes, phthalocyanine dyes, imidazoquinoxaline dyes, pyrylium / thiopyrylium dyes, azurenium dyes, squarylium dyes. Metal complex dyes such as Ni, Cr, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, merocyanine dyes, oxonol dyes, aminium dyes and diimmonium dyes, and Mention may be made of nitroso compounds. Among these dyes, cyanine dyes, phthalocyanine dyes, azurenium dyes, squarylium dyes, oxonol dyes and imidazoquinoxaline dyes are preferable.
The recording layer may be a single layer or a multilayer. The recording layer generally has a thickness of 20 to 500 nm, preferably 30 to 300 nm, and more preferably 50 to 200 nm.

In the case of the rewritable type, the recording layer is preferably made of a phase change type optical recording material composed of at least Ag, Al, Te, and Sb that can take at least two states of a crystalline state and an amorphous state. Such a recording layer can be formed by a known method.
A known dielectric layer is formed on the recording layer as necessary.

[Light reflection layer]
For the light reflection layer, a light reflective material having a high reflectance with respect to laser light is used. The reflectance is preferably 70% or more.
As a light reflective material having a high reflectance, Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd , Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi, and other metals and semi-metals or stainless steel. These light reflecting materials may be used alone, or may be used in combination of two or more kinds or as an alloy. Among these, Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel are preferable. Particularly preferred is Au, Ag, Al or an alloy thereof, and most preferred is Au, Ag or an alloy thereof.
The thickness of the light reflecting layer is generally in the range of 10 to 300 nm, and preferably in the range of 50 to 200 nm.

[Protective layer, protective substrate]
A protective layer is preferably provided on the reflective layer or the recording layer for the purpose of physically and chemically protecting the recording layer and the like. Note that in the case of adopting the same form as in the case of manufacturing a DVD-R type optical information medium, that is, a structure in which two substrates are bonded with the recording layer inside, it is not always necessary to provide a protective layer. As a material for the protective layer, inorganic substances such as SiO ₂ , MgF ₂ , SnO ₂ , and Si ₃ N ₄ , organic substances such as thermoplastic resins, thermosetting resins, and UV curable resins can be used. The thickness of the protective layer is generally in the range of 0.1 to 100 μm.

Further, for example, a light transmission layer for improving adhesion to the recording layer may be provided between the reflective layer and the recording layer in accordance with the characteristics of the recording layer.
Any material can be used as the light transmission layer as long as it has a transmittance of 90% or more at the laser wavelength.
The light transmission layer can be formed by a conventionally known method, and the thickness of the light transmission layer is preferably 2 to 50 nm.

The protective layer prevents moisture from entering and scratching. The material constituting the protective layer is preferably an ultraviolet curable resin, a visible light curable resin, a thermosetting resin, silicon dioxide, or the like, and more preferably an ultraviolet curable resin. Examples of the ultraviolet curable resin include ultraviolet curable resins such as “SD-640” manufactured by Dainippon Ink and Chemicals, Inc. Further, SD-347 (manufactured by Dainippon Ink & Chemicals, Inc.), SD-694 (manufactured by Dainippon Ink & Chemicals, Inc.), SKCD1051 (manufactured by SKC), and the like can be used. The thickness of the protective layer is preferably in the range of 1 to 200 μm, and more preferably in the range of 50 to 150 μm.
In addition, the protective layer is required to have transparency in a layer configuration used as a laser optical path. Here, “transparency” means that the recording light and the reproduction light are so transparent that the light is transmitted (transmittance: 90% or more).

  The information medium according to the present invention has a narrower track pitch than that of a conventional DVD or the like and is used by appropriately setting the track pitch of the pregroove formed on the substrate and the material constituting the recording layer. The present invention can also be applied to an information medium capable of recording / reproducing information with a laser beam having a wavelength smaller than that of light.

  The thickness of the information medium according to the present invention is preferably 0.3 mm, more preferably 0.5 mm, and even more preferably 0.7 mm as the lower limit. Moreover, as an upper limit, 100 mm is preferable, 20 mm is more preferable, and 5 mm is further more preferable. If it is too thin, defects may occur when bent. If it is too thick, the removable property may be inferior.

<Method of manufacturing information medium>
Next, an information medium manufacturing method of the present invention will be described. First, a method for manufacturing an information medium without a printable layer will be described.

[Formation of information boards and protective boards]
The information substrate and the protective substrate can be formed by injection molding, compression molding, or injection compression molding using the aforementioned substrate material. Alternatively, the stamper can be compression-molded by attaching a stamper to one side of a molding die of a hydraulic press machine and pressing the resin heated to the vicinity of the melting point.

[Formation of recording layer]
The recording layer is prepared by dissolving the recording material such as the dye in a suitable solvent together with a binder and the like, and then applying the dye solution to the surface of the substrate (information substrate) on which the pregroove is formed. It is formed by drying after forming a coating film.
As a coating method, the temperature when applying the spin coating method is preferably 23 ° C. or higher, and more preferably 25 ° C. or higher. The upper limit of the temperature is not particularly limited, but the temperature needs to be lower than the flash point of the solvent, and preferably 35 ° C.

  As a method for dissolving the recording substance or the like, a method such as ultrasonic treatment, homogenizer, or heating can be applied.

  Solvents used for preparing the dye solution include esters such as butyl acetate, ethyl lactate, and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, and chloroform; Amides such as dimethylformamide; Hydrocarbons such as methylcyclohexane; Ethers such as tetrahydrofuran, ethyl ether, dioxane; Alcohols such as ethanol, n-propanol, isopropanol, n-butanol diacetone alcohol; 2,2,3,3-tetra Fluorine solvents such as fluoropropanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether; It can gel.

  The above solvents can be used alone or in combination of two or more in consideration of the solubility of the recording material used. Various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be further added to the coating solution depending on the purpose.

The recording layer can contain various anti-fading agents in order to improve the light resistance of the recording layer.
As the antifading agent, a singlet oxygen quencher is generally used. As the singlet oxygen quencher, those described in publications such as known patent specifications can be used.
Specific examples thereof include JP-A Nos. 58-175893, 59-81194, 60-18387, 60-19586, 60-19587, and 60-35054. 60-36190, 60-36191, 60-44554, 60-44555, 60-44389, 60-44390, 60-54892, JP-A-60-47069, JP-A-63-209995, JP-A-4-25492, JP-B-1-38680, JP-A-6-26028, etc., German Patent 350399, and Japan Examples include those described in Chemical Society Journal, October 1992, page 1141.

  The amount of the antifading agent such as the singlet oxygen quencher used is usually in the range of 0.1 to 50% by weight, preferably 0.5 to 45% by weight, based on the amount of the compound for recording. More preferably, it is the range of 3-40 mass%, Most preferably, it is the range of 5-25 mass%.

  Representative examples of the antifading agent include nitroso compounds, metal complexes, diimmonium salts, and aminium salts. Examples of these are described in, for example, JP-A-2-300288, JP-A-3-224793, and JP-A-4-146189.

  Examples of the binder include natural organic polymer substances such as gelatin, cellulose derivatives, dextran, rosin, rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene, polyisobutylene, polyvinyl chloride, polyvinylidene chloride, Vinyl resins such as polyvinyl chloride and polyvinyl acetate copolymers, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resins, butyral resins, rubber derivatives, phenol / formaldehyde resins And a synthetic organic polymer such as an initial condensate of a thermosetting resin. When the binder is used, the amount of the binder used is generally 0.2 to 20 parts by mass, preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the dye. It is.

  The application temperature is 20 to 40 ° C., but there is no particular problem, but it is preferably 25 to 35 ° C., more preferably 27 to 33 ° C. The relative humidity at the time of application may be 20 to 60% RH, preferably 30 to 50% RH, and more preferably 35 to 45% RH.

[Formation of light reflection layer]
The light reflecting layer can be formed on the recording layer, for example, by vapor deposition, sputtering or ion plating of the reflective material. In the present invention, for the purpose of improving storage stability or changing the appearance, the reflective layer may be formed by laminating the above materials as a single layer or by laminating two or more materials in multiple layers.

[Formation of protective layer]
In the case of an inorganic substance, the protective layer can be formed by a method such as vacuum vapor deposition, sputtering, or coating, and in the case of an organic substance, the protective layer can be formed by laminating a plastic film or coating and drying a coating solution dissolved in a solvent. Alternatively, the protective layer can be formed, for example, by laminating a film obtained by extrusion of plastic on the reflective layer via an adhesive. In the case of a thermoplastic resin or a thermosetting resin, it can also be formed by dissolving these in a suitable solvent to prepare a coating solution, and then applying and drying the coating solution. In the case of a UV curable resin, it can also be formed by preparing a coating solution as it is or by dissolving it in a suitable solvent, coating the coating solution, and curing it by irradiating with UV light. In these coating liquids, various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added according to the purpose.

In order to prevent warping of the disk, it is preferable to irradiate the coating film with ultraviolet rays using a pulsed light irradiator (preferably a UV irradiator). The pulse interval is preferably msec or less, and more preferably μsec or less. 1 pulse irradiation light amount is not particularly limited, and is preferably 3 kW / cm ² or less, 2 kW / cm ² or less being more preferred.
The number of times of irradiation is not particularly limited, but is preferably 20 times or less, and more preferably 10 times or less.

In the case of DVD-R and DVD-RW, instead of the protective layer, an adhesive layer made of an ultraviolet curable resin or the like and a substrate as a protective substrate (thickness: about 0.6 mm, material is the same as the above substrate) are laminated. To do.
That is, after forming the light reflection layer, an ultraviolet curable resin (Dai Nippon Ink Chemical Co., Ltd. SD640 or the like) is applied to a thickness of 20 to 60 μm by spin coating to form an adhesive layer. On the formed adhesive layer, for example, a polycarbonate substrate (thickness: 0.6 mm) as a protective substrate is placed, and the ultraviolet curable resin is cured by being irradiated with ultraviolet rays from the substrate, and bonded together.

  As described above, an information medium comprising a laminate in which a recording layer, a light reflection layer, a protective substrate (dummy substrate) with a recording layer, a protective layer, or an adhesive layer provided on the substrate is provided.

[Formation of printable layer]
In the production method of the present invention, a printable layer is formed on the side opposite to the recording layer of the information medium obtained as described above.

(Formation of underlayer)
When forming an underlayer, the formation method is not ask | required, but it is preferable to form a radiation curable resin by screen printing from a viewpoint of productivity. The radiation curable resin is a resin that is cured by electromagnetic waves such as ultraviolet rays, electron beams, X-rays, γ-rays, and infrared rays. Among them, ultraviolet rays and electron beams are preferable. Further, in order to make the base layer have a layer thickness of 15 μm or more, the screen printing / radiation curing process may be performed a plurality of times so that the total layer thickness becomes 15 μm or more. In other words, a plurality of layers less than 15 μm may be stacked to form 15 μm or more.

(Formation of ink receiving layer)
As described above, the ink receiving layer is formed by a method of crosslinking and curing a coating layer in which a coating solution for an ink receiving layer containing at least fine particles, a binder, and a crosslinking agent is coated on the base layer. Is preferred. Hereinafter, the ink receiving layer coating solution will be described.

-Coating solution for ink receiving layer-
In the present invention, the ink receiving layer coating solution containing at least fine particles, a binder, and a crosslinking agent can be prepared, for example, as follows. In the following example, vapor phase silica is used as the fine particles, and polyvinyl alcohol is used as the binder.
That is, by adding gas phase method silica in water (for example, 10 to 20% by mass) and using a high-speed rotating wet colloid mill (for example, CLEARMIX (M Technique Co., Ltd.)), for example, 10,000 rpm (preferably Is dispersed under high speed rotation conditions of 5000 to 20000 rpm for 20 minutes (preferably 10 to 30 minutes), and then an aqueous polyvinyl alcohol solution (for example, PVA having a mass of about 1/3 that of vapor phase silica). And dispersion can be performed under the same rotation conditions as described above. The obtained coating liquid is a uniform sol, and a porous ink receiving layer having a three-dimensional network structure can be formed by coating and forming this on a substrate by the following coating method. As the dispersion treatment method, various conventionally known dispersers such as a high-speed rotating disperser, a medium stirring disperser (ball mill, sand mill, etc.), an ultrasonic disperser, a colloid mill disperser, and a high pressure disperser are used. However, in the present invention, a colloid mill disperser or a high-pressure disperser is preferably used from the viewpoint of efficiently dispersing the formed fine particles.

In the present invention, the surface tension of the ink receiving layer coating solution is set to 5 × 10 ⁻² N / m or less. As described above, when the thickness of the ink receiving layer is increased more than necessary, there is a problem in that the warp of the disk (information medium) occurs due to the internal stress of the layer. Therefore, in the present invention, by reducing the surface tension of the ink receiving layer coating solution to 5 × 10 ⁻² N / m or less, the volume change of the coating film during drying is reduced, and the internal stress of the coating film is reduced. Can be small. As a result, the warpage of the disk is suppressed and good disk mechanical characteristics can be obtained. When the surface tension of the ink receiving layer coating liquid exceeds 5 × 10 ⁻² N / m, the volume change of the coating film during drying increases, and as a result, good disk mechanical properties cannot be obtained.

The surface tension of the coating liquid for the ink receiving layer is more preferably at most 4.5 × 10 ^-2 N / m, more preferably not more than 4.0 × 10 ^-2 N / m. The lower limit of the surface tension of the ink receiving layer coating solution is preferably 2.0 × 10 ⁻² N / m.

  In order to adjust the surface tension of the coating solution for the ink-receiving layer to the above range, a method of adding a surfactant can be mentioned. Examples of the surfactant include cationic, anionic, nonionic, amphoteric, fluorine, and silicon. Any of the surfactants can be used. Specific examples of the surfactant that can be used in the present invention are listed below.

  Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenyl ethers (for example, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene Ethylene nonylphenyl ether), oxyethylene / oxypropylene block copolymer, sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monooleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid esters (for example, polyoxyethylene) Sorbitan monolaurate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan Lyolate, etc.), polyoxyethylene sorbitol fatty acid esters (eg, polyoxyethylene sorbitol tetraoleate), glycerin fatty acid esters (eg, glycerol monooleate), polyoxyethylene glycerin fatty acid esters (polyoxymonostearate) Ethylene glycerol, monooleic acid polyoxyethylene glycerin, etc.), polyoxyethylene fatty acid esters (polyethylene glycol monolaurate, polyethylene glycol monooleate, etc.), polyoxyethylene alkylamine, acetylene glycols (eg, 2, 4, 7) , 9-tetramethyl-5-decyne-4,7-diol, and ethylene oxide adducts, propylene oxide adducts, etc. of the diols) Sialic sharp emission alkyl ethers are preferable. Moreover, the said nonionic surfactant may be used independently and may use 2 or more types together.

  Examples of the amphoteric surfactants include amino acid type, carboxyammonium betaine type, sulfoammonium betaine type, ammonium sulfate betaine type, imidazolium betaine type, etc., for example, U.S. Pat. No. 3,843,368, Those described in JP-A-59-49535, JP-A-63-236546, JP-A-5-303205, JP-A-8-262742, and JP-A-10-282619 can be suitably used. As the amphoteric surfactant, an amino acid type amphoteric surfactant is preferable, and as the amino acid type amphoteric surfactant, as described in JP-A-5-303205, for example, an amino acid (glycine, glutamic acid, Derivatized from histidine acid and the like, and specifically, N-aminoacyl acids and salts thereof into which a long-chain acyl group has been introduced. The amphoteric surfactants may be used alone or in combination of two or more.

Examples of the anionic surfactant include fatty acid salts (for example, sodium stearate, potassium oleate), alkyl sulfate esters (for example, sodium lauryl sulfate, triethanolamine lauryl sulfate), and sulfonates (for example, sodium dodecylbenzenesulfonate). Alkyl sulfosuccinate (for example, sodium dioctyl sulfosuccinate), alkyl diphenyl ether disulfonate, alkyl phosphate, and the like.
Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, pyridinium salts, imidazolium salts, and the like.

Examples of the fluorosurfactant include compounds derived via an intermediate having a perfluoroalkyl group using a method such as electrolytic fluorination, telomerization, or oligomerization.
Examples thereof include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl trialkyl ammonium salts, perfluoroalkyl group-containing oligomers, and perfluoroalkyl phosphate esters.
Among the fluorosurfactants, the telomer type fluorosurfactant is a surfactant obtained from a fluorochemical compound obtained by telomerization of tetrafluoroethylene, and is generally represented by the following general formulas 1 to 2. Is a surfactant having a fluorinated alkyl group.

_{C n F 2n + 1 (CH} 2 CH 2) m - Formula 1

C _n F _2n + 1 -CO- Formula 2

  In the above formula, n represents an integer of 4 or more, and m represents an integer of 1 or more.

  Examples of the surfactant having such a group include a low molecular compound (also referred to as a straight-chain type) and a high molecular compound (also referred to as a polymerization type) having these groups.

  Examples of the low molecular weight compound include compounds represented by the following general formula.

Rf—CH ₂ CH ₂ —X ¹ General formula 3

Rf-CO-X ² general formula 4

In the above formula, Rf is a fluorinated alkyl chain, in particular _{C 10 F 21 -, C 8} F 17 -, C 6 F 13 -, C 5 F ll -, C 4 F 9 - , and the like .
X ¹ is —OH, —O (CH ₂ CH ₂ O) ₁ —H, —SCH ₂ CH ₂ COO—M, —S 0 ₃ —M, —O—P (═O) (OM) ₂ , — _{OCO-L-COOM, -SO 2} NR 2 -CH 2 CH 2 OH, such as -SO ^₂ NR ₂ -CH ₂ COOM and the like.
In the above formula, l is an integer of 1 or more, M is a counter cation such as a hydrogen atom or a metal ion, R ² is an alkyl group, L is — (CH ₂ ) ₂ —, — (CH ₂ ) ₃ —, Represents orthophenylene, —CH═CH— and the like.

Examples of X ² include —OH and —NH—R ³ .
R ³ is an alkyl group containing a hydrogen atom, an alkyl group, an ammonium group, etc., for example, — (CH ₂ ) ₃ —N ⁺ R ⁴ R ⁵ R ⁶ Y ⁻ , — (CH ₂ ) ₃ —N ⁺ R ⁴ R ⁵ R ⁷ COO, etc. Here, R ⁴ , R ⁵ , and R ⁶ represent an alkyl group, an aryl group, etc., R ⁷ represents an alkylene group, and Y ⁻ represents a halogen or the like.

  Examples of the polymer compound include polymers obtained from monomers of the following general formulas 5 to 6, and copolymers with monomers copolymerizable therewith.

In the above formula, Rf represents the same as in the above general formula 3 and general formula 4, and R ¹ represents a hydrogen atom or a methyl group. R ² is an alkyl group or the like.

  Examples of monomers copolymerizable with these include (meth) acrylic acid, (meth) acrylic acid alkyl ester, [for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, quintile (meth) acrylate, octyl (meth) acrylate, (meth) (Meth) acrylic acid C-18 alkyl ester such as 2-ethylhexyl acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like. ], (Meth) acrylic acid cycloalkyl ester [for example, (meth) acrylic acid cyclohexyl, (meth) acrylic acid norbornyl and the like. ], (Meth) acrylic acid aryl ester [for example, (meth) acrylic acid phenyl etc. ], Aralkyl esters [for example, benzyl (meth) acrylate and the like. ], Substituted (meth) acrylic acid alkyl ester [for example, 2-hydroxyethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, etc. ],

(Meth) acrylic acid esters containing polyether groups, [for example, diethylene glycol monomethyl ether mono (meth) acrylate, diethylene glycol monoethyl ether mono (meth) acrylate, dipropylene glycol monomethyl ether mono (meth) acrylate, dipropylene glycol Monoethyl ether mono (meth) acrylate, triethylene glycol monomethyl ether mono (meth) acrylate, triethylene glycol monoethyl ether mono (meth) acrylate, tripropylene glycol monomethyl ether mono (meth) acrylate, tripropylene glycol monoethyl ether mono (Meth) acrylate, polyethylene glycol monomethyl ether mono (meth) acrylate, polyethylene Glycol monoethyl ether mono (meth) Akurirenito, polypropylene glycol monomethyl ether mono (meth) acrylate, polypropylene glycol monoethyl ether mono (meth) acrylate. ], (Meth) acrylamides [for example, (meth) acrylamide, dimethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide and the like. ], Aromatic vinyl [for example, styrene, vinyl toluene, α-methyl styrene, etc. ], Vinyl esters [for example, vinyl acetate, vinyl propionate, vinyl versatate, etc. ], Allyl esters [for example, allyl acetate and the like. ], Halogen-containing monomers [for example, vinylidene chloride, vinyl chloride and the like. ], Vinyl cyanide [for example, (meth) acrylonitrile and the like. ], Olefins [for example, ethylene, propylene and the like. ].

  Specifically, MegaFuck F470, MegaFuck F472, MegaFuck F473, MegaFuck F475, MegaFuck F476, MegaFuck F1405, MegaFuck F178K, MegaFuck F-140NK, manufactured by Dainippon Ink & Chemicals, Inc. Zonyl FSP manufactured by Duposi, FSE, TBS, FS-62, FSA, FSO, FSN, FS-300, FS-310, FSN-100, FSO-100, manufactured by Daikin Industries DS101, DS202, DS401 and the like.

Examples of the silicone surfactant include a side chain of a compound (silicone compound) having an organopolysiloxane portion such as polydimethylsiloxane and / or a compound having a hydrophilic group or a hydrophilic polymer chain at the terminal. -General. Examples of the hydrophilic group and the hydrophilic polymer chain include polyether bonds (polyethylene oxide, polypropylene oxide, copolymers thereof, and the like), polyglycerin (C ₃ Η ₆ O (CH ₂ CH (OH) CH ₂ O), and the like. _N- H), pyrrolidone, betaine (C ₃ Η ₆ N ⁺ Me ₂ —CH ₂ COO—, etc.), sulfate (C ₃ H ₆ O (C ₂ H ₄ O) _n —SO ₃ Na etc.), Examples thereof include phosphates (such as C _{3 2 6} O (C ₂ H ₄ O) _n —P (═O) OHONa) and quaternary salts (such as C ₃ H ₆ N ⁺ Me ₃ Cl ⁻ ). In the above chemical formula, n represents an integer of 1 or more.

  Also, polydimethylsiloxane having a polymerizable vinyl group at the terminal and other copolymerizable monomers (preferably a hydrophilic monomer such as (meth) acrylic acid or a salt thereof is used as at least a part of the monomer) Examples thereof include vinyl copolymers having a silicone compound chain such as polydimethylsiloxane in the side chain obtained by copolymerization.

  Among these, in the present invention, the compound having an organopolysiloxane part is preferably a compound having a hydrophilic polymer chain, and the hydrophilic polymer chain is particularly preferably one containing a polyether bond.

  Specifically, surfactants suitable for the present invention include KF640, KF642, KF351A, KF352A, KF353A, KF354A, KF355A, KF-615, KF-945, KF-618, KF manufactured by Shin-Etsu Silicone Co., Ltd. -6004, SH3746 oil, SH3748 oil, SH3749 oil, SH3771 oil, SH8400, manufactured by Toray Dow Corning Silicon Co.

  Among the above surfactants, preferred are silicone surfactants and telomer type fluorine surfactants.

In the present invention, since the surface tension of the ink receiving layer coating solution is 5 × 10 ⁻² N / m or less, the above surfactants are appropriately selected. It is preferable to adjust the addition amount of 001 to 2.0% (preferably 0.01 to 1.0%).

  If necessary, a pH adjuster, an antistatic agent, and the like can be further added to the ink receiving layer coating solution.

  The ink receiving layer coating solution is applied by, for example, an application method using an extrusion die coater, bar coater, roll coater, blade coater, screen coater, tampo coater, spray coater, spin coater, curtain coater, dip coater, or the like. Can do. After the coating, the formed coating layer is dried. In this case, the drying is generally performed by heating the coating layer at 40 to 150 ° C. for 0.5 to 10 minutes, preferably 40 to 100 ° C. For 0.5 to 5 minutes. The drying of the coating layer will be described later.

When the ink receiving layer coating liquid is applied by, for example, an extrusion die coater, the discharged coating liquid is a flow rate from the ejection port of the extrusion die coater (the flow rate of the coating solution at the discharge port) according to the linear velocity. It is preferable to apply so that it increases from the inner periphery toward the outer periphery. Thus, by applying the coating liquid for the ink receiving layer by changing the coating amount according to the peripheral diameter using the extrusion die coater, the layer thickness of the ink receiving layer can be easily set within a desired range.
Specifically, the extrusion die is applied close to the radial position from 25 mm to 55 mm, but the width of the discharge port (slit width) is 2 to 11 times at the position of 55 mm with respect to the position of 25 mm. It is preferable to design. With this design, it is possible to adjust the coating amount (the flow rate of the coating liquid at the discharge port), and as a result, it is possible to obtain a color material receiving layer having a desired film thickness.

  When applying by spray coating, the pressure is preferably 1.013 to 2026 hPa, more preferably 50.65 to 1013 hPa, and still more preferably 101.3 to 506.5 hPa. The spread angle of the spray is preferably 1 to 120 °, more preferably 10 to 60 °, and still more preferably 20 to 50 °. As a liquid particle size, 0.1-1000 micrometers is preferable, 1-500 micrometers is more preferable, and 10-100 micrometers is further more preferable. The distance from the work (information medium) is preferably 1 to 1000 mm, more preferably 10 to 200 mm, and still more preferably 30 to 100 mm. As temperature, 10-40 degreeC is preferable, 15-35 degreeC is more preferable, and 20-30 degreeC is further more preferable. As humidity, 5-70% RH is preferable, 10-40% RH is more preferable, 20-50% RH is further more preferable.

  When applying by spin coating, the viscosity of the coating solution is preferably 0.1 to 10,000 mPa · s, more preferably 1 to 6000 mPa · s, and still more preferably 10 to 3000 mPa · s. In order to secure the thickness of the coating liquid for the ink receiving layer, 50 to 10,000 mPa · s is preferable, 100 to 6000 mPa · s is more preferable, and 200 to 3000 mPa · s is more preferable. The number of rotations is preferably 10 to 1000 rpm, more preferably 50 to 600 rpm, and even more preferably 100 to 400 at the time of dispensing. At the time of swing-off, the number of rotations is gradually increased, and the method of raising may be step or gentle. Specifically, it is preferably 100 to 10000 rpm, more preferably 200 to 5000 rpm, and more preferably 300 to 3000 rpm. More preferably. As for the shape of a nozzle, it is preferable that length is 1-100 mm, It is more preferable that it is 5-50 mm, It is further more preferable that it is 10-30 mm. The inner diameter of the nozzle is preferably 0.1 to 5 mm, more preferably 0.3 to 3 mm, and still more preferably 0.5 to 2 mm. The wall thickness of the nozzle is preferably 0.1 to 1 mm, and more preferably 0.2 to 0.5 mm. Moreover, you may install a nozzle diagonally along a flow. The distance from the workpiece is preferably 0.5 to 100 mm, more preferably 1 to 50 mm, and even more preferably 2 to 20 mm. As temperature, 10-40 degreeC is preferable, 15-35 degreeC is more preferable, and 20-30 degreeC is further more preferable. As humidity, 5-70% RH is preferable, 10-40% RH is more preferable, 20-50% RH is further more preferable.

The ink receiving layer may be dried by any drying method such as natural drying, warm air drying, infrared / far infrared drying, high frequency drying, oven drying, and the like.
In the case of natural drying, the drying time of the ink receiving layer coating solution is preferably 0.1 to 10,000 seconds, more preferably 1 to 1000 seconds, and further preferably 10 to 500 seconds. The drying temperature is preferably 0 to 40 ° C, more preferably 10 to 35 ° C, and further preferably 20 to 30 ° C. The drying humidity is preferably 10 to 70% RH, more preferably 20 to 60% RH, and further preferably 30 to 50% RH.

  In the case of warm air drying, the drying time of the ink receiving layer coating solution is preferably 0.1 to 5000 seconds, more preferably 1 to 1000 seconds, and further preferably 10 to 500 seconds. . The drying temperature is preferably 40 to 200 ° C, more preferably 60 to 150 ° C, and further preferably 80 to 130 ° C. The drying humidity is preferably 0.01 to 50% RH, more preferably 0.1 to 30% RH, and further preferably 1 to 20% RH.

  In the case of low temperature set drying, the drying temperature of the coating layer is preferably 2 to 25 ° C, more preferably 5 to 15 ° C. The dry humidity is preferably 10 to 50% RH, and more preferably 10 to 30% RH. The temperature / humidity is preferably increased gradually or stepwise from low temperature and low humidity to high temperature and high humidity as the drying progresses. Note that the wind speed is preferably 3 m / s or more in parallel with the coating layer if a reduced drying rate is indicated.

In the case of infrared / far-infrared drying, the drying time of the ink receiving layer coating solution is preferably 0.1 to 1000 seconds, more preferably 1 to 500 seconds, and more preferably 10 to 300 seconds. More preferably. The output is preferably 10 to 2000 W, more preferably 50 to 1500 W, and even more preferably 100 to 1000 W.
The drying conditions for high-frequency drying are the same as those for infrared / far-infrared drying.

  In the case of oven drying, the drying time of the ink receiving layer coating solution is preferably 0.1 to 1000 seconds, more preferably 1 to 500 seconds, and even more preferably 10 to 300 seconds. .

  The above shows the formation of an ink receiving layer containing at least fine particles, a binder, and a crosslinking agent. However, the present invention is not limited thereto, and the formation of the ink receiving layer is described in, for example, You may carry out as described in 208105 gazette, Unexamined-Japanese-Patent No. 11-301098, Unexamined-Japanese-Patent No. 11-321085, and Unexamined-Japanese-Patent No. 2000-351266.

  Moreover, water, an organic solvent, or these mixed solvents can be used as a solvent in each process. Examples of the organic solvent that can be used for this coating include alcohols such as methanol, ethanol, n-propanol, i-propanol, and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. It is done.

  After forming the ink receiving layer, the ink receiving layer is subjected to calendering through a roll nip under heat and pressure using, for example, a super calender, gloss calender or the like, to thereby achieve surface smoothness, glossiness, transparency and coating. It is possible to improve the film strength. However, the calendar process may cause a decrease in the porosity (that is, the ink absorptivity may be decreased), so it is necessary to set conditions under which the decrease in the porosity is small.

As roll temperature in the case of performing a calendar process, 30-150 degreeC is preferable and 40-100 degreeC is more preferable.
Moreover, as a linear pressure between rolls at the time of a calendar process, 50-400 kg / cm is preferable and 100-200 kg / cm is more preferable.

In the case of ink jet recording, the thickness of the ink receiving layer needs to have an absorption capacity sufficient to absorb all of the droplets, and therefore needs to be determined in relation to the porosity in the layer. For example, if the ink amount is 8 nL / mm ² and the porosity is 60%, a film having a layer thickness of about 1 μm or more is required.
Considering this point, in the case of inkjet recording, the thickness of the ink receiving layer is preferably 1 to 200 μm, more preferably 5 to 100 μm, and further preferably 10 to 60 μm.

The pore diameter of the ink receiving layer is preferably 0.005 to 0.030 μm, more preferably 0.01 to 0.025 μm in terms of median diameter.
The porosity and the median diameter of the pores can be measured using a mercury porosimeter (trade name: Bore Sizer 9320-PC2, manufactured by Shimadzu Corporation).

In addition, the ink receiving layer is preferably excellent in transparency, as a guide, the haze value when the ink receiving layer is formed on a transparent film support is preferably 30% or less, More preferably, it is 20% or less.
The haze value can be measured using a haze meter (HGM-2DP: Suga Test Instruments Co., Ltd.).

  As described above, by having the fine particles, the binder, and the crosslinking agent in the ink receiving layer, the ink receiving layer can be dried and contracted during the formation of the porous structure without lowering the other ink receiving performance. It is possible to suppress and prevent film cracking. In addition, when the ink receiving layer contains a vapor-phase process silica and has a three-dimensional network structure with a porosity of 50 to 80%, a high-resolution and high-density image can be formed while exhibiting good ink absorption, and high temperature and high humidity. It is possible to simultaneously ensure excellent ink-receptive performance such as aging blur in the environment is suppressed and the formed image also exhibits high light resistance and water resistance.

As described above, the ink receiving layer of the information medium according to the present invention can reduce the amount of ultraviolet rays irradiated to the information medium, and improves the recording characteristics such as jitter, unlike those formed by the ultraviolet curable resin. be able to. Moreover, there is no skin irritation like ultraviolet curable resin, and handling safety is high.
In addition, the ink jet recording sheet is cracked on the surface when bent with a strong force. However, the information medium according to the present invention is thicker than the ink jet recording sheet, and the information medium according to the present invention is subjected to external stress such as bending. Strong against it.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, “parts” and “%” all represent “parts by mass” and “% by mass”.

[Example 1]
<< Production of disk-shaped substrate >>
A polycarbonate resin (resin brand name: Panlite AD5503, Teijin Ltd.) is injected into an injection molding machine equipped with a stamper prepared in advance so as to have a predetermined groove shape at a predetermined track pitch, and a temperature of 115 ° C. To produce a polycarbonate disk-shaped resin substrate. The obtained disk-shaped resin substrate had a diameter of 120 mm and a thickness of 1.2 mm, and a spiral concave groove (pre-groove) was formed on the surface thereof. The track pitch of the concave groove was 1.6 μm, the groove width was 500 nm, and the groove depth was 180 nm.

  A coating solution for forming a recording layer was prepared by dissolving 2.5 g of a cyanine dye represented by the following structural formula in 100 ml of 2,2,3,3-tetrafluoropropanol. This coating solution was applied by spin coating on the surface of the disk-shaped polycarbonate substrate obtained above, on which the pregroove was provided, and a recording layer (thickness: 190 nm (groove portion), 110 nm (land portion)) Formed.

  Next, Ag was sputtered on the recording layer using a DC magnetron sputtering apparatus to form a reflective layer made of Ag having a thickness of about 120 nm. Further, a UV curable resin (trade name: SD318, manufactured by Dainippon Ink & Chemicals, Inc.) was applied on the reflective layer using a spin coating method while changing the rotational speed between 300 and 4000 rpm. After the application, a protective layer having a thickness of 5 μm was formed by irradiating it with ultraviolet rays using a high pressure mercury lamp and curing it. Through the above steps, a CD-R type information medium (optical disc) composed of a substrate, a recording layer, a reflective layer, and a protective layer was manufactured.

  Next, a printable layer was formed as follows on the protective layer opposite to the incident surface of the recording / reproducing laser beam.

-Formation of underlayer-
UV curable ink (White No. 3, manufactured by Teikoku Mfg. Co., Ltd.) is printed on the protective layer on the side opposite to the substrate surface by screen printing. After printing, 80 W / cm of UV light is applied from above using a metal halide lamp. Irradiated and cured, two 8 μm ground layers (white layers) were repeatedly formed to a total thickness of 16 μm. As the screen, a Tetron screen having 300 lines / inch mesh, a yarn diameter of 31 μm, and an opening of 38 μm was used.

  Next, in order to form an ink receiving layer on the underlayer, the following steps were performed.

-Preparation of coating liquid A for ink receiving layer-
(1) Gas phase method silica fine particles and (2) ion-exchanged water having the following composition are mixed, and using a high-speed rotating colloid mill (CLEAMIX, manufactured by M Technique Co., Ltd.) at a rotational speed of 10,000 rpm for 20 minutes. Dispersed. Thereafter, the aqueous dispersion was mixed with a first solution composed of (3) polyoxyethylene lauryl ether, (4) 9% polyvinyl alcohol aqueous solution, and (5) diethylene glycol monobutyl ether, (6) boric acid, (7 A mordant and (8) a second solution composed of ion-exchanged water were added, respectively, and redispersion was performed under the same conditions as above to prepare an ink-receiving layer coating solution A.
The mass ratio between the silica fine particles and the water-soluble resin (PB ratio / (1) :( 4)) is 3.5: 1, and the pH of the ink-receiving layer coating liquid A is 3.4. Indicated.
The surface tension of the coating liquid A for the ink receiving layer was measured at a liquid temperature of 20 ° C. using a surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd. The measurement results are shown in Table 1.

[Composition of coating liquid A for ink receiving layer]
(1) Gas phase method silica fine particles (inorganic pigment fine particles) 10.0 parts (average primary particle diameter: 7 nm; Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water 55.2 parts [first solution]
(3) Polyoxyethylene lauryl ether (surfactant) 0.04 part (Emulgen 109P (10%), manufactured by Kao Corporation, HLB value 13.6)
(4) Polyvinyl alcohol 9% aqueous solution (water-soluble resin) 31.7 parts (PVA420, manufactured by Kuraray Co., Ltd., saponification degree 81.8%, polymerization degree 2,000)
(5) 0.5 parts of diethylene glycol monobutyl ether (compound represented by general formula (1))
[Second solution]
(6) Boric acid (6%; crosslinking agent) 10.4 parts (7) Mordant (PAS-F5000; 20% aqueous solution, manufactured by Nittobo Co., Ltd.) 2.5 parts (8) 5.3 parts of ion-exchanged water

-Formation of ink receiving layer-
After the corona discharge treatment was performed on the surface of the base layer of the information medium, the ink receiving layer coating liquid A obtained above was applied onto the base layer using an extrusion die coater.
Then, it was dried in a low temperature and low humidity chamber at 50 ° C. and 10% RH until the fluidity of the coating solution on the surface was suppressed. The coating layer showed a constant rate of drying during this period. Immediately after that, it was dried for 10 minutes in a hot air dryer in an environment of 20 ° C. and 20% RH (wind speed: 4 m / sec). As a result, an information medium of Example 1 in which an ink receiving layer having a dry film thickness of 35 μm was provided was produced.

[Example 2]
Polycarbonate substrate (thickness: 0.6 mm, outer diameter: 120 mm, inner diameter: 15 mm, manufactured by Teijin Ltd., trade name “Panlite AD5503” formed with a spiral groove (land) and LPP on the surface by injection molding. ") Was produced. The groove depth was 140 nm, the groove width was 310 nm, and the groove pitch was 740 nm.

  1 g of a dye obtained by mixing the following oxonol dye (A) and oxonol dye (B) in a ratio of 65:35 is dissolved in 100 ml of 2,2,3,3-tetrafluoro-propanol, and a recording layer forming coating solution is obtained. Prepared. This recording layer forming coating solution was applied to the groove surface of the obtained substrate by spin coating while changing the rotational speed from 300 to 3000 rpm, and dried to form a recording layer. The thickness of the recording layer was measured by observing the cross section of the recording layer with an SEM, and found to be 150 nm in the groove and 110 nm in the land portion.

  Next, a reflective layer made of Ag having a thickness of about 150 nm was formed on the recording layer by DC sputtering in an argon atmosphere. The pressure in the chamber was 0.5 Pa.

  Further, a UV curable resin (trade name “SD-318”, manufactured by Dainippon Ink & Chemicals, Inc.) is annularly dispensed on the reflective layer, and a separately prepared polycarbonate disk-shaped protective substrate (diameter: 120 mm). , Thickness: 0.6 mm) with the centers aligned, and rotated for 3 seconds at a rotational speed of 5000 rpm to spread UV curable resin (SD640, manufactured by Dainippon Ink & Chemicals, Inc.) over the entire surface and extra The UV curable resin was shaken off. When the UV curable resin spreads over the entire surface, the UV curable resin was cured by irradiating ultraviolet rays with a high pressure mercury lamp, and the substrate on which the recording layer and the reflective layer were formed was bonded to the disk-shaped protective substrate. The thickness of the bonding layer was 25 μm, and it was possible to bond without mixing bubbles.

  Next, the base layer and the ink receiving layer are formed on the surface of the disk-shaped protective substrate in the same manner as in “Forming the base layer” and “Ink receiving layer” in Example 1, and the information medium of Example 2 is manufactured. did.

[Example 3]
The information medium of Example 3 was produced in the same manner as in Example 2 except that the amount of surfactant added to the coating liquid for the ink receiving layer in “Formation of ink receiving layer” in Example 2 was changed to 0.5 part. did.

[Comparative Example 1]
Example 1 is the same as Example 1 except that the ink receiving layer is replaced with an ultraviolet curable resin (UV SP 81019B, manufactured by Teikoku Ink Manufacturing Co., Ltd.) that is formed by screen printing and ultraviolet curing. Thus, an information medium of Comparative Example 1 was produced.

[Comparative Example 2]
An information medium of Comparative Example 2 was produced in the same manner as in Example 2 except that the surfactant of the ink receiving layer coating liquid in “Ink Receptive Layer Formation” of Example 2 was not added.

<Performance evaluation>
The following evaluation was performed about the information medium of Examples 1-3 obtained from the above, and the information medium of Comparative Examples 1-2.

[printing]
Images were printed on the printable layers of the information media of Examples 1 to 3 and Comparative Examples 1 and 2 using an inkjet printer (manufactured by Seiko Epson Corporation; PM-970C).
[Image quality evaluation]
Subsequently, ten persons visually evaluated sensory evaluation of the printed image with respect to the printed information medium of Examples 1-3 and Comparative Examples 1-2. The case where all 10 people evaluated that it was more beautiful than the conventional product was evaluated as ◯, and the case where it was evaluated as being equal to or less than the conventional product was evaluated as ×. The results are shown in Table 1.
[Brightness evaluation]
A grid-like linear pattern (line width 0.28 mm) in which magenta ink and black ink are adjacent to each other is printed on the printable layer of the information medium of Examples 1 to 3 and Comparative Examples 1 and 2 using the printer. did. After leaving for 3 hours after printing, the line width of the black portion was measured and evaluated according to the following criteria. The evaluation results are shown in Table 1.
[Standard]
A: The occurrence of blurring with time was hardly observed, and the condition was good.
(Line width: 0.28 to 0.30 mm)
○: Some blurring with time was observed, but it was at a level of no practical problem.
(Line width: 0.31-0.35mm)
X: Striking over time was remarkably recognized, and it was a level causing a problem in practical use.
(Line width: 0.35mm or more)
[Evaluation of warpage]
Radial tilt was measured for the information media of Examples 1 to 3 and the information media of Comparative Examples 1 and 2. For the measurement, a DVD mechanical property evaluation apparatus DLD4000 (manufactured by Japan EMM Co., Ltd.) was used, and 512 locations were measured on the outer peripheral edge (r = 55 mm) of the colorant receiving layer. The average value is shown in Table 1.
In addition, in the information medium, 0.8 deg or less was a level having no problem in practical use, and 0.8 deg or less was evaluated as “◯”, and those exceeding it were evaluated as “x”.

From Table 1, the information media of Examples 1 to 3 have less blurring and could be printed with high image quality, whereas the information medium of Comparative Example 1 has much blurring, and the image quality is the same print quality as the conventional product. there were. Moreover, in the information media of Examples 1 to 3, the resolution was high and a fine texture was produced. In particular, the hair could be printed clearly. Further, it can be seen that the information media of Examples 1 to 3 were less warped and excellent in mechanical properties.
In contrast, although the information medium of Comparative Example 2 had no problem with respect to the image quality, it was found that the occurrence of warpage could not be suppressed and the mechanical characteristics were inferior.

Claims (3)

A method for producing a disk-shaped information medium comprising a step of applying a coating liquid for an ink receiving layer containing at least fine particles, a binder, and a crosslinking agent on a base layer to form a printable layer,
A method for producing an information medium, wherein the ink receiving layer coating liquid has a surface tension of 5 × 10 ⁻² N / m or less.   The fine particles are at least one selected from gas phase method silica, pseudoboehmite, and aluminum oxide, the binder is polyvinyl alcohol, the cross-linking agent is a boron compound, and the ink receiving The method for producing an information medium according to claim 1, wherein the coating liquid for layer further contains a mordant.   3. The ink receiving layer coating liquid is applied by an extrusion die coater so that a flow rate from an ejection port increases from an inner peripheral portion toward an outer peripheral portion in accordance with a linear velocity. The manufacturing method of the information medium of description.