JP2006216134A - Coating material composition and optical information medium using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating material composition useful for forming a protective coat layer, having proper hardness and superior antistatic properties on the surface of an optical information medium, and to provide an optical information medium that uses the coating material composition. <P>SOLUTION: The coating material composition for the optical information medium contains at least a quaternary ammonium compound (A), having an active energy ray-polymerizable group and a quaternary ammonium salt group, a curable compound (B) having three or more active energy ray-polymerizable groups in a molecule and silica fine particles (C) whose surfaces are modified. The optical information medium has the protective coat layer 8, containing a cured material of the coating material composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating composition useful for forming a protective coating layer having sufficient hardness and excellent antistatic properties on the surface of an optical information medium.

  The present invention also provides a read-only optical disc, an optical recording disc, a magneto-optical recording disc, and the like having a protective coating layer having a sufficient hardness and excellent antistatic properties formed by using the coating agent composition. The present invention relates to an optical information medium.

  It prevents dust and atmospheric oil mist from adhering to the surface of optical information media such as read-only optical discs, optical recording discs, and magneto-optical recording discs, and reduces noise in electrical signals due to charging of optical information media. Therefore, antistatic properties are required.

  In addition to optical information media, for example, optical lenses, optical filters, antireflection films, and the surface of various display elements such as liquid crystal displays, CRT displays, plasma displays, EL displays, etc. are the same as in the case of optical disks. In addition, antistatic properties are required to prevent adhesion of dust and oil mist in the atmosphere, and to reduce noise to electrical signals due to charging of the display element.

  A protective coat layer made of a cured product of an ultraviolet curable material is usually provided on the surface of the optical disk or the above various objects. Such a protective coating layer is insulative and causes a charging phenomenon due to static electricity.

  JP-A-5-225612 relates to a coating agent having an antistatic effect and an optical information medium using the same, and a monomer and / or oligomer having at least one polymerizable ethylenic double bond in the molecule, a polymerization initiator And a coating agent comprising a quaternary ammonium salt having an acryloyl group. [0032] For the quaternary ammonium salt, 3- (meth) acryloxy-2-hydroxypropyltrimethylammonium chloride, 3- (meth) acryloxy-2-hydroxypropyltrimethylammonium methyl sulfate, (meth) acrylamidopropyl Trimethylammonium chloride, (meth) acrylamidopropyltrimethylammonium methyl sulfate and the like are disclosed. [0033] discloses that the addition amount of the quaternary ammonium salt is 0.5 to 30 parts by weight with respect to 100 parts by weight of the monomer and / or oligomer.

  JP-A-6-329819 relates to a method for coating an antistatic protective film. [0007] In [0007], the antistatic agent is an amine compound or the like having at least one acryloyl group in the molecule, and the compound is an ultraviolet ray. It is disclosed that it is cured by irradiation and fixed in a protective film of an ultraviolet curable resin. [0017] includes quaternary ammonium salts such as 3- (meth) acryloxy-2-hydroxypropyltrimethylammonium sulfate and (meth) acrylamidopropyltrimethylammonium sulfate.

  Japanese Patent Laid-Open No. 6-180859 relates to an optical disc coating agent and an optical disc excellent in scratch resistance and antistatic properties, and has 20 to 99% by weight of (meth) acrylate ester having a quaternary ammonium base and alkylene oxide ( Copolymer (A), trifunctional (meth) acrylic acid ester (B), bifunctional (meth) acrylic acid ester (C), monofunctional (meth) acrylic acid with 80 to 1% by weight of meth) acrylic acid ester A coating agent containing an ester (D), a hydroxyl group-containing (meth) acrylic acid ester (E), and a photopolymerization initiator (F) is disclosed. In the copolymer (A), the quaternary ammonium base is located in the side chain.

  JP-A-6-19549 discloses an optical disk having a hard coat layer made of a cured film of an ultraviolet curable resin composition containing an antistatic agent, and a quaternary ammonium salt as a hydrophilic part of the antistatic agent. In [0009], a functional group such as a (meth) acryloyl group is exemplified as the hydrophobic moiety [0010].

  In JP-A-2003-173575, a recording layer is formed on an optical disc support base in an optical disc in which recording / reproducing laser light is irradiated onto the recording layer through a thin film cover layer (X), and 50 to 150 μm is formed on the recording layer. A thin film cover layer (X) having a thickness is formed, and a hard coat layer (Y) having a thickness of 0.05 to 20 μm is formed on the thin film cover layer (X). The thin film cover layer (X) is cured with a specific active energy ray. The hard disk layer (Y) is a cured product layer of a specific active energy ray-curable composition (Q) containing a surface-modified colloidal silica. Yes. [0027] discloses that the composition (P) may contain an antistatic agent, and [0044] discloses that the composition (Q) may contain an antistatic agent. , [0031] include nonionic antistatic agents, cationic antistatic agents, and anionic antistatic agents as antistatic agents.

  Japanese Patent Laid-Open No. 2002-230837 also discloses the same technology as the above-mentioned Japanese Patent Laid-Open No. 2003-173575 regarding an optical disc.

  Japanese Patent No. 3047094 discloses an antistatic agent having a (meth) acryloyl group at both molecular ends and a quaternary ammonium base in a repeating unit constituting the main chain. Japanese Patent Application Laid-Open No. 8-291281 discloses that an antistatic effect is high due to the presence of an ionic group in the main chain of a molecule ([0006], [0062]).

JP-A-5-225612 JP-A-6-329819 Japanese Patent Laid-Open No. 6-180859 Japanese Patent Application Laid-Open No. 6-19549 JP 2003-173575 A JP 2002-230837 A Japanese Patent No. 3047094 JP-A-8-291281

  However, the above-described conventional technology cannot provide a protective coating layer having sufficient hardness and antistatic properties. In particular, a protective coating layer capable of maintaining sufficient antistatic properties even when used for a long period of time in an optical disk usage environment has not been obtained. On the other hand, the surface of an optical disc is required to have antifouling properties from the viewpoint of recording / reproducing information.

  Therefore, an object of the present invention is to provide a coating agent composition useful for forming a protective coating layer having sufficient hardness on the surface of an optical information medium and excellent in antistatic properties.

  Another object of the present invention is to provide an optical information medium having a protective coating layer having sufficient hardness and excellent antistatic properties on the recording and / or reproducing beam incident side surface.

  As a result of intensive studies, the present inventors have found that sufficient hardness can be obtained by using both a quaternary ammonium compound having an active energy ray-polymerizable group and a quaternary ammonium base, and surface-modified colloidal silica fine particles. It was found that a coating composition capable of forming a protective coating layer having an antistatic property and excellent antistatic properties can be obtained.

The present invention includes the following inventions.
(1) a quaternary ammonium compound (A) having an active energy ray polymerizable group and a quaternary ammonium base, and a curable compound (B) having three or more active energy ray polymerizable groups in the molecule; A coating composition for optical information media, comprising at least surface-modified silica fine particles (C).

  (2) The coating composition according to (1), wherein the surface-modified silica fine particles (C) are surface-modified with a silane coupling agent having a (meth) acryloyl group or a mercapto group.

  (3) The surface-modified silica fine particles (C) are obtained by reacting the silane coupling agent in an amount of 5 to 150 parts by weight with respect to 100 parts by weight of unmodified silica fine particles. (1) The coating agent composition as described in (2).

  (4) The coating composition according to any one of (1) to (3), wherein the quaternary ammonium compound (A) has a (meth) acryloyl group as an active energy ray polymerizable group. .

(5) The coating agent composition contains 2 parts by weight or more and 20 parts by weight or less of the quaternary ammonium compound (A) with respect to 100 parts by weight of the nonvolatile content in the composition, and the curable compound (B). The coating agent composition according to any one of (1) to (4), comprising 5 parts by weight or more and 500 parts by weight or less of the silica fine particles (C) with respect to 100 parts by weight.
Nonvolatile content includes the ammonium compound (A), the curable compound (B), and the silica fine particles (C), curable monomers and oligomers other than the curable compound (B) described later, a photopolymerization initiator, Optional components such as various additives are included.

  (6) An optical information medium having a film body composed of one or more layers including at least a recording layer or a reflective layer on a support substrate, wherein the support substrate side surface and the film body side surface An optical information medium in which at least one surface is formed by a protective coating layer containing a cured product of the coating agent composition according to any one of (1) to (5).

  (7) The coating composition according to any one of (1) to (5), having an information recording layer on the support substrate and a light transmission layer on the information recording layer, An optical information medium having a protective coating layer containing a cured product of the above.

  (8) The protective coating layer further has a cured product of a silicone compound having an active energy ray polymerizable group or a fluorine-containing compound having an active energy ray polymerizable group on the surface thereof, (6) or (7) An optical information medium described in 1.

  In the present invention, the optical information medium includes various media such as a read-only optical disk, an optical recording disk, and a magneto-optical recording disk.

  ADVANTAGE OF THE INVENTION According to this invention, the coating agent composition useful in order to form the protective coating layer which has sufficient hardness on the surface of an optical information medium, and is excellent in antistatic property is provided.

  In addition, according to the present invention, there is provided an optical information medium having a protective coating layer having sufficient hardness and excellent antistatic properties on the recording and / or reproducing beam incident side surface using the coating agent composition. The

  Furthermore, according to the present invention, there is provided an optical information medium having a protective coating layer having sufficient hardness on the recording and / or reproducing beam incident side surface, excellent antistatic properties, and excellent antifouling properties. .

  First, the coating composition for optical information media of the present invention will be described.

  The coating agent composition of the present invention comprises a quaternary ammonium compound (A) having an active energy ray polymerizable group and a quaternary ammonium base, and a curable property having three or more active energy ray polymerizable groups in the molecule. It contains at least compound (B) and surface-modified silica fine particles (C).

  The curable compound (B) is other than the quaternary ammonium compound (A), is the main component of the curable component in the coating composition, and is the main component of the protective coat layer matrix obtained after curing. . Since the curable compound (B) has three or more active energy ray-polymerizable groups in the molecule, sufficient hardness as a protective coating layer can be obtained after curing.

  The curable compound (B) may be a polyfunctional monomer or oligomer as long as it has three or more active energy ray polymerizable groups in the molecule, and its structure is not particularly limited. The active energy ray polymerizable group of the curable compound (B) is selected from (meth) acryloyl groups, vinyl groups, and mercapto groups.

  Among such active energy ray-curable compounds (B), examples of the compound having a (meth) acryloyl group include tri- or more functional urethane acrylates, epoxy acrylates, ester acrylates, and the like, specifically, trimethylol. Propane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol tri (meth) acrylate, etc., but are not necessarily limited to these Is not to be done.

  In the coating agent composition of the present invention, only one type of active energy ray-curable compound (B) may be used, or two or more types may be used in combination.

  In addition to the curable compound (B), the coating agent composition contains a curable compound having one or two active energy ray polymerizable groups in the molecule up to 35% by weight based on the entire curable component. May be included in quantity. If the monofunctional or bifunctional compound is too much, it is difficult to obtain sufficient hardness as a protective coating layer.

  The quaternary ammonium compound (A) is used for an antistatic function. The quaternary ammonium compound (A) has at least one active energy ray polymerizable group and at least one quaternary ammonium base in the molecule.

  As the active energy ray polymerizable group of the quaternary ammonium compound (A), a (meth) acryloyl group is preferable. By the (meth) acryloyl group, the quaternary ammonium compound (A) is fixed in the cured protective coating layer by active energy ray irradiation, and the antistatic function is maintained.

  The anion which is a counter ion of the quaternary ammonium salt is selected from halogen atoms such as fluorine, chlorine, bromine and iodine, or sulfate groups, alkyl sulfate groups, alkyl phosphate groups, nitrate groups, carboxylic acid groups and the like.

  Examples of the quaternary ammonium compound (A) include (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acrylamidopropyltrimethylammonium chloride, and 3- (meth) acryloxy-2-hydroxypropyltrimethylammonium chloride. .

  The quaternary ammonium compound (A) may be a (co) polymer containing the above compound. For example, the compound etc. which gave the acrylate to the copolymer of methacryloyloxyethyl trimethyl ammonium chloride and 4-hydroxybutyl methacrylate using hexamethylene diisocyanate and 2-hydroxyethyl methacrylate, etc. are mentioned.

  In particular, as the quaternary ammonium compound (A), those in which a quaternary ammonium base is present on the main chain in the molecule are also preferable. It is also preferred that a quaternary ammonium base is repeatedly present in the main chain. It is considered that the antistatic function is improved by the presence of an ionic group in the main chain of the molecule. As these quaternary ammonium salts, for example, N-methyldiethanolamine (MEA) and dimethyl adipate (AA) are used for transesterification, and both ends are hydroxyl intermediates (MEA-AA-MEA-AA-MEA). ) And quaternized with dimethyl sulfate, and then compounds obtained by reacting the hydroxyl groups at both ends with hexamethylene diisocyanate and 2-hydroxyethyl methacrylate, respectively.

  The surface-modified silica fine particles (C) are used for increasing the hardness of the protective coating layer and further improving the wear resistance. The silica fine particles (C) are preferably surface-modified with a silane coupling agent having a (meth) acryloyl group or a mercapto group. Such reactive silica fine particles undergo a crosslinking reaction by irradiation with active energy rays when the coating agent layer is cured, and are fixed in the polymer matrix. Further, since the surface of the silica fine particles is modified, the quaternary ammonium compound (A) can be stably present in the coating agent. The silica fine particles (C) may be in the form of powder or colloid.

  Examples of such reactive silica fine particles include reactive silica fine particles described in JP-A-9-100111, and can be preferably used in the present invention.

  Further, the average particle size of the silica fine particles (C) is 100 nm or less, preferably 20 nm or less in order to ensure the transparency of the protective coating layer. is there.

  Surface modification with a silane coupling agent can be performed by stirring the silane coupling agent and unmodified silica fine particles in an organic solvent such as ethyl cellosolve or propylene glycol monomethyl ether acetate at room temperature or under heating. . The alkoxy group of the silane coupling agent is hydrolyzed to form a bond between the hydroxyl residue (silanol residue) on the silica fine particle surface and Si of the silane coupling agent, and the silane coupling agent is chemically immobilized. Is done.

  In this surface modification, it is preferable to hydrolyze the silane coupling agent in advance. The hydrolysis may be performed by mixing and stirring a silane coupling agent, water in the same molar amount as the hydrolyzable group, and an acid catalyst such as hydrochloric acid and acetic acid or an alkali catalyst such as ammonia and sodium hydroxide. By stirring the hydrolyzed silane coupling agent and unmodified silica fine particles in an organic solvent such as ethyl cellosolve and propylene glycol monomethyl ether acetate at room temperature or under heating, the surface of the silica fine particles is treated with silane. The coupling agent is chemically immobilized.

  In this way, a (meth) acryloyl group or a mercapto group is introduced on the surface of the silica fine particles.

  In the surface modification with the silane coupling agent, the silane coupling agent may be reacted with, for example, about 5 to 150 parts by weight, preferably about 20 to 50 parts by weight with respect to 100 parts by weight of the unmodified silica fine particles. If the silane coupling agent is less than 5 parts by weight, the effect of introducing a (meth) acryloyl group or mercapto group tends to be small, and the effect of stabilizing the quaternary ammonium compound (A) in the coating agent tends to be small. is there. On the other hand, if 150 parts by weight of the silane coupling agent is used, a sufficient amount of (meth) acryloyl group or mercapto group is introduced. Further, if the silane coupling agent is 20 parts by weight or more, the quaternary ammonium compound (A) can maintain a cationic state more stably in the protective coating layer, and as a result, the antistatic effect is enhanced. Can keep.

  In the present invention, the coating agent composition contains 2 parts by weight or more and 20 parts by weight or less of the quaternary ammonium compound (A) with respect to 100 parts by weight of the nonvolatile content in the composition, and the curable compound (B ) It is preferable that 5 parts by weight or more and 500 parts by weight or less of the surface-modified silica fine particles (C) are included with respect to 100 parts by weight. Here, the non-volatile component is a component remaining in the protective coating layer after curing, and in addition to the ammonium compound (A), the curable compound (B), and the silica fine particles (C), bifunctional or monofunctional monomers and oligomers , Optional components such as a photopolymerization initiator and various additives are included.

  When the addition amount of the quaternary ammonium compound (A) is preferably 2 parts by weight or more, more preferably 5 parts by weight or more, a high antistatic effect can be obtained. On the other hand, even if the addition amount of the quaternary ammonium compound exceeds 20 parts by weight, the antistatic effect is not so much improved, and the hardness of the protective coating layer tends to be lowered. A more preferable addition amount of the quaternary ammonium compound (A) is 5 parts by weight or more and 20 parts by weight or less.

  The addition amount of the surface-modified silica fine particles (C) is preferably 5 parts by weight or more and 500 parts by weight or less, and more preferably 20 parts by weight or more and 200 parts by weight or less with respect to 100 parts by weight of the curable compound (B). If the silica fine particle (C) is contained in an amount of more than 500 parts by weight, the film strength of the protective coat layer tends to be weak, whereas if it is less than 5 parts by weight, the abrasion resistance of the protective coat layer is improved by adding the silica fine particle (C) The effect is weak.

  The coating agent composition of the present invention may contain a known photopolymerization initiator. The photopolymerization initiator is not particularly required when an electron beam is used as the active energy ray, but is required when ultraviolet rays are used. The photopolymerization initiator may be appropriately selected from ordinary ones such as acetophenone, benzoin, benzophenone, and thioxanthone. Among the photopolymerization initiators, examples of the photo radical initiator include Darocur 1173, Irgacure 651, Irgacure 184, and Irgacure 907 (all manufactured by Ciba Specialty Chemicals). Content of a photoinitiator is about 0.5 to 5 weight% with respect to the sum total of said (A), (B), and (C), for example in a coating agent composition.

  In addition, the coating agent composition of the present invention may further include a non-polymerizable diluent solvent, an organic filler, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, an antifoaming agent, a leveling agent, etc., if necessary. May be included.

  The coating agent composition can be produced by mixing the above-described components by a conventional method. The coating agent composition may be adjusted to a viscosity suitable for application. The coating agent composition of this invention is comprised as mentioned above.

  Next, with reference to the drawings, an optical information medium of the present invention (hereinafter sometimes abbreviated as an optical disk) using the coating agent composition and a method for producing the same will be described.

  The optical information medium of the present invention has a film body composed of one layer or a plurality of layers including at least a recording layer or a reflective layer on a support substrate, and the support substrate side surface and the film body side surface At least one surface is formed by a protective coat layer containing a cured product of the coating agent composition. In the optical information medium of the present invention, at least one of the support substrate side surface and the film body side surface, preferably the recording / reproducing beam incident side, is made of a cured product of the coating agent composition. It is preferably formed by a protective coat layer.

  As an example of the optical information medium, an optical information medium whose film body side surface is the recording / reproducing beam incident side surface will be described with reference to FIGS.

  FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the optical disc of the present invention. This optical disc is a recording medium having a recording layer (4) as an information recording layer on a relatively rigid support base (20) and a light transmission layer (7) on the recording layer (4). And a light-transmitting protective coat layer (8) on the light-transmitting layer (7). The protective coating layer (8) is on the recording / reproducing beam incident side, and a laser beam for recording or reproducing is incident on the recording layer (4) through the protective coating layer (8) and the light transmission layer (7). The thickness of the light transmission layer (7) including the protective coating layer (8) is preferably 30 to 150 μm, more preferably 70 to 150 μm. Such an optical disc is, for example, a Blu-ray Disc. It has a hardness of B or more in the pencil hardness test on the protective coat layer (8) side.

  Although not shown, an optical disc having two or more recording layers in which a recording layer is further provided on the recording layer (4) via a spacer layer is also included in the present invention. In this case, the optical disc has a light transmission layer (7) and a protective coat layer (8) on the recording layer farthest from the support base (20).

  The present invention can be applied regardless of the type of the recording layer. That is, for example, it can be applied to a phase change recording medium, a pit formation type recording medium, and a magneto-optical recording medium. Normally, a dielectric layer and a reflective layer are provided on at least one side of the recording layer for the purpose of protecting the recording layer and optical effects, but the illustration is omitted in FIG. Further, the present invention is not limited to the recordable type as shown in the figure, but can be applied to a reproduction-only type. In that case, a pit row is formed integrally with the support substrate (20), and a reflective layer (metal layer or dielectric multilayer film) covering the pit row forms an information recording layer.

The optical information medium in the case of the phase change recording medium of the present invention will be described.
FIG. 2 is a schematic cross-sectional view showing an example of the layer structure of the optical disc of the present invention. In FIG. 2, the optical disk has a reflective layer (3), a second dielectric layer (52), a phase change on the surface of the support substrate (20) on which fine irregularities such as information pits and pregrooves are formed. The recording material layer (4) and the first dielectric layer (51) are provided in this order, the light transmission layer (7) is provided on the first dielectric layer (51), and the light transmission layer (7) is provided on the light transmission layer (7). It has a protective coat layer (8). In this example, the reflective layer (3), the second dielectric layer (52), the phase change recording material layer (4), and the first dielectric layer (51) constitute an information recording layer. The information recording layer and the light transmission layer (7) constitute a film body necessary for recording or reproduction. This optical disk is used so that laser light for recording or reproduction enters through the protective coating layer (8) and the light transmission layer (7), that is, from the film body side.

  The support base (20) has a thickness of 0.3 to 1.6 mm, preferably 0.4 to 1.3 mm, and has information pits and pregrooves on the surface on which the recording layer (4) is formed. Etc. are formed.

  The support substrate (20) is used so that the laser beam is incident from the side of the film body as described above. Therefore, the support substrate (20) does not need to be optically transparent, but as the transparent material, polycarbonate resin, polymethyl methacrylate ( Various plastic materials such as acrylic resins such as PMMA) and polyolefin resins can be used. Alternatively, glass, ceramics, metal, or the like may be used. In the case of using a plastic material, the concavo-convex pattern is often created by injection molding, and in the case of other than the plastic material, it is formed by a photopolymer method (2P method).

  On the support substrate (20), the reflective layer (3) is usually formed by sputtering. As a material for the reflective layer, a metal element, a metalloid element, a semiconductor element, or a compound thereof is used alone or in combination. Specifically, for example, a known reflective layer material such as Au, Ag, Cu, Al, or Pd may be selected. The reflective layer is preferably formed as a thin film having a thickness of 20 to 200 nm.

  The second dielectric layer (52), the phase change recording material layer (4), the first dielectric layer (51) directly on the reflective layer (3) or directly on the support base (20) when there is no reflective layer. ) Are formed in this order by sputtering.

  The phase change recording material layer (4) is reversibly changed between a crystalline state and an amorphous state by laser light irradiation, and is formed of a material having different optical characteristics between the two states. For example, Ge—Sb—Te, In—Sb—Te, Sn—Se—Te, Ge—Te—Sn, In—Se—Tl, In—Sb—Te, and the like can be given. Further, these materials contain a trace amount of at least one of metals selected from Co, Pt, Pd, Au, Ag, Ir, Nb, Ta, V, W, Ti, Cr, Zr, Bi, In, and the like. It may be added, or a reducing gas such as nitrogen may be added in a trace amount. The thickness of the recording material layer (4) is not particularly limited and is, for example, about 3 to 50 nm.

  The second dielectric layer (52) and the first dielectric layer (51) are formed on both sides of the upper and lower surfaces of the recording material layer (4). The second dielectric layer (52) and the first dielectric layer (51) have a function as an interference layer for adjusting optical characteristics as well as a mechanical and chemical protection function of the recording material layer (4). Each of the second dielectric layer (52) and the first dielectric layer (51) may be composed of a single layer or a plurality of layers.

  The second dielectric layer (52) and the first dielectric layer (51) are respectively Si, Zn, Al, Ta, Ti, Co, Zr, Pb, Ag, Zn, Sn, Ca, Ce, V, Cu, It is preferably formed from an oxide, nitride, sulfide, fluoride, or a composite thereof containing at least one of metals selected from Fe and Mg. The extinction coefficient k of each of the second dielectric layer (52) and the first dielectric layer (51) is preferably 0.1 or less.

  The thickness of the second dielectric layer (52) is not particularly limited, and is preferably about 20 to 150 nm, for example. The thickness of the first dielectric layer (51) is not particularly limited, and is preferably about 20 to 200 nm, for example. The reflection can be adjusted by selecting the thicknesses of the two dielectric layers (52) and (51) within such a range.

  On the first dielectric layer (51), the light transmission layer (7) is formed using an active energy ray curable material or a light transmission sheet such as a polycarbonate sheet.

  The active energy ray-curable material used for the light transmissive layer (7) is UV curable on the condition that it is optically transparent, has little optical absorption and reflection in the used laser wavelength region, and has low birefringence. Select from materials and electron beam curable materials.

  Specifically, the active energy ray curable material is preferably composed of an ultraviolet ray (electron beam) curable compound or a composition for polymerization thereof. Examples of such compounds include ester compounds of acrylic acid and methacrylic acid, acrylic double bonds such as epoxy acrylate and urethane acrylate, allyl double bonds such as diallyl phthalate, and unsaturated double bonds such as maleic acid derivatives. Mention may be made of monomers, oligomers, polymers, etc. containing or introduced in the molecule a group which is crosslinked or polymerized by ultraviolet irradiation such as bonding. These are preferably polyfunctional, particularly trifunctional or more, and may be used alone or in combination of two or more. Moreover, you may use a monofunctional thing as needed.

  As the UV curable monomer, a compound having a molecular weight of less than 2000 is preferable, and as the oligomer, a molecular weight of 2000 to 10,000 is preferable. Examples of these include styrene, ethyl acrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol methacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, and the like. Examples thereof include pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, (meth) acrylate of phenol ethylene oxide adduct, and the like. . In addition, examples of the ultraviolet curable oligomer include oligoester acrylate and an acrylic modified product of urethane elastomer.

  The ultraviolet (electron beam) curable material may contain a known photopolymerization initiator. The photopolymerization initiator is not particularly required when an electron beam is used as the active energy ray, but is required when ultraviolet rays are used. The photopolymerization initiator may be appropriately selected from ordinary ones such as acetophenone, benzoin, benzophenone, and thioxanthone. Among the photopolymerization initiators, examples of the photo radical initiator include Darocur 1173, Irgacure 651, Irgacure 184, and Irgacure 907 (all manufactured by Ciba Specialty Chemicals). The content of the photopolymerization initiator is, for example, about 0.5 to 5% by weight with respect to the ultraviolet (electron beam) curable component.

  Moreover, as an ultraviolet curable material, the composition containing epoxy compounds, such as an alicyclic epoxy compound, and a photocationic polymerization catalyst is used suitably. Any known photocationic polymerization catalyst may be used without any particular limitation.

  In the formation of the light transmission layer (7), the application of the active energy ray-curable material on the first dielectric layer (51) may be performed by a spin coating method.

  Or in this invention, a light transmissive layer can also be formed using light transmissive resin sheets, such as a polycarbonate sheet. In this case, an active energy ray-curable material similar to that for the light transmission layer is applied on the first dielectric layer (51) to form an uncured resin material layer. A light transmissive sheet as a light transmissive layer (7) is placed on the uncured resin material layer, and then the resin material layer is cured by irradiating with active energy rays such as ultraviolet rays. The sheet is adhered to form a light transmission layer (7).

  A protective coating layer (8) is formed on the light transmission layer (7) using the coating agent composition. That is, the coating composition is applied on the light transmission layer (7) to form an uncured protective coating layer, and then irradiated with active energy rays such as ultraviolet rays, electron beams, visible light, etc. Is cured to form a protective coat layer (8).

  The coating method is not limited, and various coating methods such as spin coating, dip coating, and gravure coating may be used. Alternatively, when a light-transmitting sheet is used as the light-transmitting layer (7), a protective coat layer (8) is formed in advance on the long light-transmitting sheet raw material in the same manner as described above, and this original After punching the substrate into a disc shape, it may be placed on an uncured resin material layer as described above to cure the resin material layer.

  As described above, the phase change type optical recording disk illustrated in FIG. 2 is obtained as an optical information medium in which the film body side surface is the recording / reproducing beam incident side surface.

  Further, in the optical disk exemplified in FIGS. 1 and 2, the surface of the protective coating layer (8) on the recording / reproducing beam incident side is required to have antifouling properties from the viewpoint of recording / reproducing information. That is, it is necessary to prevent adhesion of the user's fingerprint component, various organic components, and dust to the surface of the protective coating layer (8) during use. The antifouling property means water repellency and oil repellency. For example, the contact angle of water on the surface of the protective coating layer is preferably 70 ° or more. Accordingly, the surface of the protective coat layer (8) is preferably antifouling treated with a silicone compound having an active energy ray polymerizable group or a fluorine-containing compound having an active energy ray polymerizable group. By having the active energy ray polymerizable group, the antifouling treatment material is immobilized on the surface of the protective coating layer by irradiation with the active energy ray, and the antifouling property of the surface over a long period is maintained.

  Examples of the silicone compound used for the antifouling treatment include compounds having a silicone moiety and an active energy ray polymerizable group selected from (meth) acryloyl group, vinyl group and mercapto group, and more specifically, for example, Although the compound shown to following formula (1) to (3) is mentioned, it is not necessarily limited to these.

_{R- [Si (CH 3) 2} O] n-R (1)
_{R- [Si (CH 3) 2} O] n-Si (CH 3) 3 (2)
_{(CH 3) 3 SiO - [} Si (CH 3) 2 0] n- [Si (CH 3) (R) O] m-Si (CH 3) 3 (3)

  Here, R is a substituent containing at least one reactive group selected from a (meth) acryloyl group, a vinyl group, and a mercapto group, n and m are degrees of polymerization, and n is 5 to 1000. , M is 2-100.

  Examples of the fluorine-containing compound used for the antifouling treatment include a fluorine-containing (meth) acrylate compound. Specifically, for example, 2,2,3,3,3-pentafluoropropyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 2,2,2-trifluoroethyl (Meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 3- (perfluoro-5-methylhexyl) -2-hydroxypropyl (meth) acrylate, 2- (perfluorooctyl) ethyl acrylate, 3-perfluorooctyl-2-hydroxypropyl (meth) acrylate, 2- (perfluorodecyl) ethyl (meth) acrylate, 2- (perfluoro-9-methyloctyl) ethyl (meth) acrylate, 3- (perfluoro -7-methyloctyl) ethyl (meth) acrylate, 2- (perfluoro-9-methyldecyl) ethyl (meth) acrylate, 1H, H, 9H-hexade Fluorinated acrylates such as fluoro nonyl (meth) acrylate, and the like, but not necessarily limited thereto.

  Examples of the fluorine-containing compound used for the antifouling treatment include (meth) acrylate compounds having a fluorine-containing polyether moiety. The fluorine-containing polyether moiety preferably includes a perfluoropolyether moiety. In such a compound, a (meth) acryloyl group is introduced into the hydroxyl group of a fluorine-containing polyether compound having a hydroxyl group at the terminal. Examples of the fluorine-containing polyether compound as the raw material include the following compounds. Of course, it is not limited to these.

HOCH ₂ -CF ₂ O- [CF ₂ CF ₂ O] l- [CF ₂ O] m-CF ₂ CH ₂ OH (Z DOL)
F- [CF ₂ CF ₂ CF ₂ O] l-CF ₂ CF ₂ CH ₂ OH (Demnum-SA)
F- [CF (CF ₃ ) CF ₂ O] l-CF (CF ₃ ) CH ₂ OH (Krytox-OH)
HO (CH ₂ CH ₂ O) n-CH ₂ -CF ₂ O- [CF ₂ CF ₂ O] l- [CF ₂ O] m-CF ₂ CH ₂ (OCH ₂ CH ₂ ) nOH (Zdol-TX)
HOCH ₂ CH (OH) CH ₂ O-CH ₂ -CF ₂ O- [CF ₂ CF ₂ O] l- [CF ₂ O] m-CF ₂ CH ₂ OCH ₂ CH (OH) CH ₂ OH (Z-Tetraol )
Here, l, m, and n each represent a polymerization degree.

As a specific example of the (meth) acrylate compound having a fluorine-containing polyether moiety,
・ As one having one or more active energy ray reactive groups per 1000 molecular weight, Fomblin Z DOL diacrylate [Fomblin Z DOL (manufactured by Augmont) acrylate-modified terminal hydroxyl group] or Fluorite ART-4 (Kyoeisha Chemical),
Fluorolite ART-3 (Kyoeisha Chemical Co., Ltd.) having two or more active energy ray reactive groups per 1000 molecular weight
-Fomblin Z-Tetraol (manufactured by Augmont) having four terminal hydroxyl groups modified with acrylate as having four or more active energy ray reactive groups per 1000 molecular weight
Etc.

  In general, a fluorine-containing compound has a higher antifouling property than a silicone compound, that is, a larger contact angle of water on the surface of the protective coat, for example, a contact angle of 90 ° or more is exhibited.

  The coating composition of the present invention can also be applied to an optical information medium in which the support substrate side surface is the recording / reproducing beam incident side surface. Conventionally, various optical information media such as DVD-ROM, DVD-R, DVD-RAM, and DVD-RW have been commercialized. Furthermore, the coating agent composition of the present invention can be suitably applied to the next generation HD-DVD in which a blue laser beam is used as a recording / reproducing beam. In these optical information media, an information recording layer is formed on one surface of a supporting substrate, and a light-transmitting protective coating layer is formed on the other surface of the supporting substrate using the coating agent composition of the present invention. The

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[Synthesis Example of Quaternary Ammonium Compound]
1444 parts by weight of laurylamine-ethylene oxide 4 mol adduct (LAEO4), 522 parts by weight of methyl adipate (AAM), and 1.5 parts by weight of dibutyltin oxide were charged into the reactor and stirred at 120 ° C. to distill ethanol. The ester exchange reaction was carried out while leaving to obtain intermediate (I) of both terminal hydroxyl groups (LAEO4-AAM-LAEO4-AAM-LAEO4-AAM-LAEO4). To this intermediate (I), 505 parts by weight of dimethyl sulfuric acid was added dropwise and aged at 70 ° C. to obtain a quaternized compound (II) having both terminal hydroxyl groups. To 1000 parts by weight of this compound (II), 220 parts by weight of isophorone diisocyanate and 115 parts by weight of 2-hydroxyethyl acrylate were added, followed by dehydration reaction at 80 ° C., and a quaternary ammonium compound having both acryloyl groups (A1) Got.

[Surface modification of colloidal silica fine particles and preparation of coating material (a)]
To 1.5 parts by weight of 3-methacryloxypropyltrimethoxysilane as a silane coupling agent, 0.3 parts by weight of pure water and 0.0075 parts by weight of 1N acetic acid were added and stirred at 50 ° C. for 2 hours. Hydrolysis of the silane coupling agent was performed. To this hydrolyzed silane coupling agent, 100 parts by weight (non-volatile content: 30 parts by weight) of unmodified colloidal silica fine particles (average particle size 12 nm, dispersion medium: propylene glycol monomethyl ether) is added, and then at 80 ° C. for 2 hours. The mixture was stirred and the volatile components of alcohol and water were distilled off to obtain surface-modified colloidal silica fine particles.

The ratio of the weight (Wc) of the silane coupling agent to the weight (Ws) of the unmodified colloidal silica fine particles (as non-volatile content) is
(Wc / Ws) × 100 = 5%.

  The obtained surface-modified colloidal silica fine particles were further added with 62.5 parts by weight of dipentaerythritol hexaacrylate, 6 parts by weight of the quaternary ammonium compound (A1), and propylene glycol monomethyl ether 30 as a non-reactive diluent solvent. A part by weight was added and stirred at room temperature to prepare a coating material (a).

[Surface modification of colloidal silica fine particles and preparation of coating materials (b) to (d)]
Each surface-modified colloidal form was the same as above except that the amounts of 3-methacryloxypropyltrimethoxysilane, pure water, and 1N acetic acid as silane coupling agents were changed as shown in Table 1. Silica fine particles were obtained.
Dipentaerythritol hexaacrylate, the quaternary ammonium compound (A1), and propylene glycol monomethyl ether as a non-reactive diluent were added to each of the surface-modified colloidal silica fine particles obtained in the amounts shown in Table 1. Otherwise, the coating materials (b) to (d) were obtained in the same manner as described above.

[Surface modification of colloidal silica fine particles and preparation of coating materials (e) to (f)]
3-Mercaptopropyltrimethoxysilane was used as a silane coupling agent. Each surface-modified colloidal silica fine particle was obtained in the same manner as above except that 3-mercaptopropyltrimethoxysilane, pure water, and 1N acetic acid were used in the amounts shown in Table 1.
Dipentaerythritol hexaacrylate, the quaternary ammonium compound (A1), and propylene glycol monomethyl ether as a non-reactive diluent were added to each of the surface-modified colloidal silica fine particles obtained in the amounts shown in Table 1. Otherwise, the coating materials (e) to (f) were obtained in the same manner as described above.

[Production of Coating Material (g) (Comparative Example)]
Colloidal silica fine particles (average particle size: 12 nm, dispersion medium: propylene glycol monomethyl ether acetate, non-volatile content: 30% by weight) not subjected to surface modification treatment, dipentaerythritol hexaacrylate, and propylene glycol as a non-reactive diluent solvent A coating material (g) was obtained in the same manner as above except that monomethyl ether was added in the amount shown in Table 1. The quaternary ammonium compound (A1) was not used.

[Production of Coating Material (h) (Comparative Example)]
Colloidal silica fine particles (average particle size: 12 nm, dispersion medium: propylene glycol monomethyl ether acetate, nonvolatile content: 30% by weight) not subjected to surface modification treatment, dipentaerythritol hexaacrylate, the quaternary ammonium compound (A1) A coating material (h) was obtained in the same manner as above except that propylene glycol monomethyl ether was added as a non-reactive diluent in the amount shown in Table 1.

  Using each of the coating materials (a) to (h), a disk sample No. 1 to 8 were produced.

[Disc Sample No. Preparation of 1]
The optical recording disk sample No. 1 having the layer structure shown in FIG. 1 was produced as follows.
Al ₉₈ Pd ₁ Cu ₁ (atomic ratio) is formed on the surface of the disk-shaped support base (20) (made of polycarbonate, diameter 120 mm, thickness 1.1 mm) on which grooves are formed for information recording. A reflective layer (3) having a thickness of 100 nm was formed by sputtering. The depth of the groove was λ / 6 expressed by the optical path length at the wavelength λ = 405 nm. The recording track pitch in the groove recording system was 0.32 μm.

Next, a second dielectric layer (52) having a thickness of 20 nm was formed on the surface of the reflective layer (3) by sputtering using an Al ₂ O ₃ target. A recording layer (4) having a thickness of 12 nm was formed on the surface of the second dielectric layer (52) by sputtering using an alloy target made of a phase change material. The composition (atomic ratio) of the recording layer (4) was Sb ₇₄ Te ₁₈ (Ge ₇ In ₁ ). The recording layer (4) surface, ZnS (80 mol%) - by SiO ₂ (20 mol%) sputtering method using a target, thereby forming a first dielectric layer having a thickness of 130 nm (51).

Next, a radical polymerizable ultraviolet curable material having the following composition was applied to the surface of the first dielectric layer (51) by spin coating, the irradiation intensity was 160 W / cm, the distance from the lamp was 11 cm, and the integrated light quantity was 3 J / cm. ^The light transmitting layer (7) was formed by irradiating ultraviolet rays at ² so that the thickness after curing was 98 μm.

(Light transmission layer: Composition of UV curable material)
50 parts by weight of urethane acrylate oligomer (Made by Mitsubishi Rayon Co., Ltd., Diabeam UK6035)
Isocyanuric acid EO-modified triacrylate 10 parts by weight (Aronix M315, manufactured by Toa Gosei Co., Ltd.)
Isocyanuric acid EO-modified diacrylate 5 parts by weight (manufactured by Toa Gosei Co., Ltd., Aronix M215)
Tetrahydrofurfuryl acrylate 25 parts by weight Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone) 3 parts by weight

  Next, the coating material (a) obtained as described above was applied onto the light transmission layer (7) by spin coating so that a protective coating layer (8) having a thickness of 2 μm after curing was obtained, A coating material film was formed.

  Further, an antifouling agent having the following composition is applied onto the coating material film by a spin coating method, and the diluted solvent inside the film is removed by heating in the atmosphere at 60 ° C. for 3 minutes. Then, an electron beam (irradiation dose: 40 kGy) was irradiated to cure both the coating material and the antifouling agent. The total thickness of the cured protective coat layer (8) and the antifouling treatment layer was about 2 μm.

(Composition of antifouling agent)
1 part by weight of perfluoropolyether diacrylate
Fomblin Z DOL diacrylate [Fomblin Z DOL (Audimont) terminal hydroxyl group modified with acrylate]
3-perfluorooctyl-2-hydroxypropyl acrylate 3 parts by weight Fluorine-based solvent (Sumitomo 3M, Fluorinert FC-77) 1600 parts by weight

  As described above, the disk sample No. 1 was produced.

[Disc Sample No. Preparation of 2-6]
As shown in Table 1, except that each coating material (b) to (f) was used, the disk sample No. In the same manner as in No. 1, disc sample No. 2 to 6 were produced.

[Disc Sample No. Preparation of 7-8 (comparative example)]
As shown in Table 1, except that each coating material (g) and (h) was used, the disk sample No. In the same manner as in No. 1, disc sample No. 7 and 8 were produced, respectively.

[Evaluation of disk sample]
The performance test shown below was performed on each manufactured disk sample. Moreover, the stability of each coating material for the protective coating layer used was also evaluated.

(Measurement of the stability of the coating material for the protective coating layer)
Each of the coating materials (a) to (h) was prepared according to the procedure described above, and then left in a dark room at room temperature for 24 hours. The state of the coating material immediately after production and after standing for 24 hours was visually confirmed. The case where there was no particular change between the state immediately after production and the state after standing for 24 hours was defined as “good”, and when gelled, it was regarded as “bad”. The results are shown in Table 1.

(Measurement of charging half-life)
In accordance with JIS L1094, the half-life of each disk sample on the protective coat surface was measured. Specifically, a test piece having a size of 35 mm × 35 mm was cut out from each disk sample, and the obtained test piece was set in a measuring instrument in a test room set at a temperature of 25 ° C. and a relative humidity of 10%. The measurement method was followed except that the measurement was performed up to the measurement time of minutes. The measurement result is obtained as the time until the charged voltage of the test piece decays to ½, that is, the half-life (minutes). The shorter this time, the better the antistatic performance. The results are shown in Table 1.

(Evaluation of hardness)
As an evaluation of hardness, the scratch resistance of the protective coat surface of each disk sample was examined. The surface of the protective coat of each disk sample was coated with steel wool no. Using 0000, 100 reciprocations were rubbed with a load of 0.98 N per cm ² . Thereafter, the presence or absence of scratches on the surface of the protective coat was visually confirmed. Any disk sample No. In 1 to 8, no scratch was observed.

(Evaluation of antifouling properties)
As an evaluation of the antifouling property, the contact angle of pure water on the protective coat surface of each disk sample was measured. The static contact angle was measured at a temperature of 20 ° C. and a relative humidity of 60% using a contact angle measuring device FACE CONTACT-ANGLEMETER manufactured by Kyowa Interface Science Co., Ltd. Any disk sample No. A contact angle of 103 degrees was also obtained for 1-8.

  From Table 1, each disk sample No. consistent with the present invention is shown. All of Nos. 1 to 6 were excellent in antistatic performance while maintaining the hardness and antifouling performance of the protective coat surface. Both antistatic properties mainly due to hydrophilic action and antifouling properties mainly due to hydrophobic action have been achieved. Moreover, the stability of each coating material for the protective coating layer used was also good.

  In contrast, the comparative disk sample No. In No. 7, since no quaternary ammonium compound was used, the stability of the coating material was good, but the antistatic property was poor. Comparison disk sample No. In No. 8, since the colloidal silica fine particles which were not surface-modified in the coating material were used, the quaternary ammonium compound could not exist stably.

  In the above embodiment, the application of the protective coat layer to the phase change type optical disk is shown. However, the present invention is applied not only to a phase change type optical disc but also to a read-only optical disc and a write once optical disc. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. Further, all modifications belonging to the equivalent scope of the claims are within the scope of the present invention.

It is a schematic sectional drawing which shows an example of the laminated constitution of the optical disk of this invention. It is a schematic sectional drawing which shows an example of the laminated constitution of the optical disk of this invention.

Explanation of symbols

(20): Support base
(3): Reflective layer
(52): Second dielectric layer
(4): Recording layer
(51): First dielectric layer
(7): Light transmission layer
(8): Protective coat layer

Claims (5)

  Surface-modified with a quaternary ammonium compound (A) having an active energy ray polymerizable group and a quaternary ammonium base, and a curable compound (B) having three or more active energy ray polymerizable groups in the molecule. A coating composition for optical information media, comprising at least silica fine particles (C).   The coating composition according to claim 1, wherein the surface-modified silica fine particles (C) are surface-modified with a silane coupling agent having a (meth) acryloyl group or a mercapto group.   The surface-modified silica fine particles (C) are obtained by reacting 100 parts by weight of unmodified silica fine particles with the silane coupling agent in an amount of 5 to 150 parts by weight. The coating agent composition according to 1 or 2.   An optical information medium having a film body composed of one or a plurality of layers including at least a recording layer or a reflective layer on a support substrate, wherein at least one of the support substrate side surface and the film body side surface The optical information medium in which the surface is formed of the protective coat layer containing the hardened | cured material of the coating agent composition of any one of Claims 1-3. The optical information medium according to claim 4, wherein the protective coating layer further has a cured product of a silicone compound having an active energy ray polymerizable group or a fluorine-containing compound having an active energy ray polymerizable group on a surface thereof.

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