JP2005225999A - Curable composition for polycarbonate substrate, polycarbonate film having hard coat layer and manufacturing method of polycarbonate film having cured layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a point defect free functional film using a polycarbonate film as a substrate; to provide a curable composition for formation of the functional layer present on the above functional film; and to provide an article mounted with the functional film, especially an image display unit and an optical recording disk. <P>SOLUTION: The curable composition, which is for a transparent polycarbonate film, contains a hardener and an organic solvent whose proportion of an organic solvent having a solubility parameter (SP value) of ≥8.3 and ≤10.5, contained in the whole organic solvent is 60 mass% or less. Also provided are the functional film having the functional layer formed with this composition and the image display unit and optical recording disk provided with this functional film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hard coat film based on a polycarbonate film free from point defects, particularly to an optical hard coat film.

  Polycarbonate is excellent in transparency, lightweight, and has good impact properties. Therefore, it is widely studied in various industries, building materials, decorative materials, and optical materials as an alternative to glass. In particular, the polycarbonate film produced by the casting method (solvent cast method) is used as a base material for optical functional films, despite its high optical anisotropy, so that its use has expanded year by year. Yes.

In recent years, a plastic cover film having a thickness of about 100 μm has been studied as a cover layer for high-density optical disks in recent years. However, a substrate having a thermal expansion coefficient approximate to that of the substrate is preferable, and a material having the same quality as the substrate is usually used. Therefore, since a polycarbonate resin is generally used as a resin substrate of an optical disk at present, a polycarbonate film is generally used also in this light transmissive base film.
When a polycarbonate film produced by the casting method (solvent cast method) is used as an optical functional film, the functional layer is formed by applying a functional material, a curable composition containing a curable resin and an organic solvent to the polycarbonate film. It is formed by curing.

A more specific explanation will be given by taking a hard coat film based on a polycarbonate film as an example. Polycarbonate films have the disadvantages of low surface hardness and poor scratch resistance. Therefore, the surface hardness has been increased by providing a hard coat layer on the surface of the polycarbonate film.
On the other hand, as a method of forming a hard coat layer on a plastic film substrate, a curable organic compound such as a polyfunctional (meth) acrylic monomer, a photopolymerization initiator as a main component, and an organic solvent as a diluent for improving the coating property A method in which an ultraviolet curable resin composition to which is added is applied to a plastic film, followed by a drying process, and ultraviolet irradiation is continuously performed roll-to-roll is highly productive and widely used. Among organic solvents, methyl ethyl ketone is widely used as a diluent because it has strong dissolving power, high boiling point and low vapor pressure.

  So far, there has been no report on examinations for defining physical properties of organic solvents in order to reduce or eliminate foreign substances in the process of applying a composition containing an organic solvent on a polycarbonate film and forming a cured layer.

Proposals have been made focusing on the solvent of the curable composition for polycarbonate film.
For example, in Patent Document 1, in order to improve the adhesion in the step of laminating a hard coat layer on a polycarbonate film as a base material, a proposal is made to control the ratio of a solvent that attacks polycarbonate and a solvent that does not attack.

Patent Document 2 proposes that the solvent of the curable composition for a polycarbonate resin has a boiling point of 120 ° C. to 160 ° C. and a solvent that dissolves the polycarbonate resin is added to provide adhesion to the polycarbonate resin substrate. Yes.
JP 2001-114916 A JP 2003-211611 A

When a functional film is produced by forming a functional layer on a polycarbonate film substrate, a diluent such as methyl ethyl ketone is generally used to control the physical properties of the coating solution and improve the coating properties. According to the present invention, the solvent such as methyl ethyl ketone penetrates into the polycarbonate film after application of the coating liquid and before drying, swells the surface non-uniformly, and has a size of about 10 μ to 100 μ at the interface between the film and the coating liquid. To produce 100 or more protrusions in a 10 cm square. When this functional film is used as an optical film for an image display device such as a liquid crystal display, for example, the protrusion is recognized as a point defect. In addition, when the present inventor uses this optical film as a protective film for an optical recording material such as an optical disc, since point defects cause noise, this is the same as when used for an image display device such as a display. It is not useful at all in use, so functional film based on polycarbonate film controls the characteristics of the organic solvent in the curable composition for forming the functional layer, and this protrusion is reduced or limited. We found out that approaching to zero is an extremely important issue.
In the method described in Patent Document 1, a solvent that attacks the polycarbonate is included in the total solvent in an amount of 70% by mass or more in order to improve the adhesion, and it is rather counterproductive to reduce foreign matter failure.
Further, in the method described in Patent Document 2, as described above, it is counterproductive to the reduction of point foreign matter failure, and the definition of the solvent that dissolves the polycarbonate resin is ambiguous, and the cured layer is as thick as 30 μm. The point defects resulting from the swelling of the polycarbonate substrate surface are buried in the hardened layer and do not cause a problem.

An object of the present invention is to provide a functional film having a polycarbonate film as a base material and free from point defects.
Another object of the present invention is to provide a curable composition for forming a functional layer on the functional film.
Still another object of the present invention is to provide an article equipped with a functional film, in particular, an image display device with few point defects and an optical recording disk with little noise.

As a result of intensive studies, the present inventors have found that the above object can be achieved by controlling the composition of the organic solvent used in the cured composition, and have completed the present invention.
That is, according to the present invention, there are provided a curable composition, a functional film, a production method thereof, an image display device, and an optical recording disk having the following constitution.
1. A curable composition for a transparent polycarbonate film substrate containing a curing agent and an organic solvent, wherein an organic solvent having a solubility parameter (SP value) of 8.3 or more and 10.5 or less is contained in all organic solvents. A curable composition for a polycarbonate film, wherein the ratio is 60% by mass or less.
2. 2. The curable composition for polycarbonate film according to 1 above, which does not contain an organic solvent having a solubility parameter (SP value) of 9.0 or more and 10.0 or less.
3. A curable composition for a transparent polycarbonate film substrate containing a curing agent and an organic solvent, wherein the proportion of the solvent (S) that attacks the polycarbonate film at 25 ° C. is 60% by mass. The curable composition for polycarbonate films characterized by the following.
4). 4. The curable composition for a polycarbonate film as described in 3 above, wherein the proportion of the solvent (S) that attacks the polycarbonate film is 50% by mass or less.
5). 4. The curable composition for a polycarbonate film as described in 3 above, wherein the proportion of the solvent (S) that attacks the polycarbonate film is 40% by mass or less.
6). 6. The curable composition for a polycarbonate film according to any one of the above 3 to 5, wherein the solubility parameter (SP value) of the solvent (S) that corrodes the polycarbonate film is 8.3 or more and 10.5 or less.
7). Although the solubility parameter (SP value) of the solvent (S) that attacks the polycarbonate film is 9.0 or more and 10.0 or less, the proportion contained in the total organic solvent is 20% by mass or less. The curable composition for polycarbonate films according to any one of 3 to 6 above.
8). Although the solubility parameter (SP value) is 9.0 or more and 10.0 or less among the solvent (S) which attacks the polycarbonate film, the ratio contained in the total organic solvent is 10% by mass or less. 8. The curable composition for a polycarbonate film as described in 7 above.
9. Although the solubility parameter (SP value) of the solvent (S) that attacks the polycarbonate film is 9.0 or more and 10.0 or less, the proportion contained in the total organic solvent is 5% or less. 8. The curable composition for a polycarbonate film as described in 7 above.
10. 8. The curable composition for a polycarbonate film as described in 7 above, which does not contain an organic solvent having a solubility parameter (SP value) of 9.0 or more and 10.0 or less.
11. 11. The curable composition for a polycarbonate film according to any one of 1 to 10 above, which contains 2 to 40% by volume of the inorganic oxide fine particles with respect to the cured film after filling.
12 12. Curing for polycarbonate film according to 11 above, wherein the inorganic fine particles are inorganic fine particles containing a dispersion of at least one inorganic oxide selected from silicon oxide, titanium oxide, zirconium oxide and aluminum oxide. Sex composition.
13. 13. The curable composition for a polycarbonate film according to any one of 1 to 12 above, which is an active energy ray curable composition.
14 A functional film obtained by directly laminating a functional layer formed by curing the curable composition for polycarbonate according to any one of 1 to 13 above on a polycarbonate film substrate.
15. 15. The functional film as described in 14 above, wherein the polycarbonate film is a polycarbonate film produced by a casting method (solvent cast method).
16. 16. The functional film as described in 14 or 15 above, wherein the functional layer has a thickness of 2.5 μm or more.
17. The functional film as described in any one of 14 to 16 above, wherein the thickness of the functional layer is 10.0 μm or less.
18. The functional film as described in any one of 14 to 17 above, wherein the thickness of the functional layer is from 2.5 μm to 4.0 μm.
19. The functional film as described in any one of 14 to 18 above, wherein the functional layer is a hard coat layer having scratch resistance by steel wool.
20. The functionality according to any one of 14 to 19 above, wherein a functional layer is formed by applying and curing the curable composition according to any one of 1 to 13 on a polycarbonate film substrate. A method for producing a film.
21. The image display apparatus carrying the functional film in any one of said 14-19.
22. 20. An optical recording disk on which the functional film according to any one of 14 to 19 is mounted.

  The functional film of the present invention in which a functional layer formed by curing a cured composition using a solvent having a specific composition of the present invention is laminated on a polycarbonate film substrate has few point defects, and image display It is suitably used as a protective film for devices, optical recording disks and the like.

Hereinafter, a functional film, particularly an optical functional film, in which the polycarbonate film of the present invention is used as a base material and a cured layer having no point defects is formed will be described in detail.
In addition, in this specification, when a numerical value represents a physical property value, a characteristic value, or the like, the description “(numerical value 1) to (numerical value 2)” represents the meaning of “numerical value 1 or more and numerical value 2 or less”.

[Polycarbonate film substrate]
The polycarbonate film substrate used in the present invention may be a film, a sheet, or a plate as long as it is made of polycarbonate. Of these, films and sheets are preferable, and roll films are particularly preferable from the viewpoint of productivity. The thickness of the film is preferably 20 to 300 μm, more preferably 60 to 200 μm, and particularly preferably 70 to 120 μm. When the thickness of the base film is in the above range, the strength of the film is strong and the rigidity is appropriate.
“Transparent” of the transparent substrate means that the light transmittance in the visible light region is 80% or more, and preferably 86% or more.
The film forming method may be a melting method or a casting method (solvent casting method), but the casting method generally has low optical anisotropy and is preferable for an optical film.

[Functional layer]
The curable composition of the present invention may be a thermosetting composition or an active energy ray curable composition as long as it contains a curing agent and an organic solvent. Since the polycarbonate film is soft and curl occurs when the cured film thickness is too large, it is preferably 10 μm or less. Further, since point defects are likely to appear at 4.0 μm or less, the present invention is effective at 4.0 μm or less. If the thickness of the cured film exceeds 4.0 μm, it is considered that point defects are buried in the cured film. Further, when the thickness of the cured coating is less than 2.5 μm, the number of point defects increases rapidly, so that the thickness is preferably 2.5 μm or more.

[Hard coat layer]
When the functional layer of the present invention is a hard coat layer, the hard coat layer is a hardened layer whose scratch resistance is improved by a steel wool test described later.

  In the method for forming a hard coat layer of the present invention, an ultraviolet curable composition that is cured by ultraviolet irradiation is applied, dried, and irradiated by the ultraviolet irradiation. A compound containing two or more ethylenically unsaturated groups in the same molecule is preferably blended in the ultraviolet curable composition because it is polymerized or crosslinked by ultraviolet irradiation and cured.

  Hereinafter, compounds containing two or more ethylenically unsaturated groups in the same molecule that can be preferably used in the present invention will be described. Preferred types of ethylenically unsaturated groups are acryloyl group, methacryloyl group, styryl group and vinyl ether group, particularly preferably acryloyl group. Although the compound containing an ethylenically unsaturated group should just have two or more ethylenically unsaturated groups in a molecule | numerator, More preferably, it is three or more. Among them, a compound having an acryloyl group is preferable, and a compound called a polyfunctional acrylate monomer having 2 to 6 acrylate groups in the molecule or a molecule called urethane acrylate, polyester acrylate or epoxy acrylate. An oligomer having several acrylate groups and a molecular weight of several hundred to several thousand can be preferably used.

Preferred examples of the compound having two or more ethylenically unsaturated groups in the molecule include divinylbenzene, ethylene glycol diacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, and pentaerythritol. Polyol polyacrylates such as tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, diacrylate of bisphenol A diglycidyl ether, epoxy acrylates such as diacrylate of hexanediol diglycidyl ether, polyisocyanate and hydroxy Urethane acrylate obtained by reaction of hydroxyl-containing acrylate such as ethyl acrylate It can gel.
Such compounds are also commercially available, and are EB-600, EB-40, EB-140, EB-1150, EB-1290K, IRR214, EB-2220, TMPTA, TMPTMA (above, Daicel UCB ( Co., Ltd.), UV-6300, UV-1700B (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and the like.
Among the compounds having 2 or more ethylenically unsaturated groups in the molecule mentioned above, particularly preferred compounds include compounds having 3 or more acryloyl groups in the molecule and an acryloyl equivalent of 120 or less, Specific examples include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like.

  What can be preferably blended in the ultraviolet curable composition of the present invention other than the compound having two or more ethylenically unsaturated groups in the molecule is a curable resin containing a ring-opening polymerizable group.

  Hereinafter, the curable resin containing a ring-opening polymerizable group that is preferably used in the curable composition of the present invention will be described. The curable resin containing a ring-opening polymerizable group is a curable resin having a ring structure in which ring-opening polymerization proceeds by the action of a cation, an anion, or a radical, and among them, a heterocyclic group-containing curable resin is preferable. Examples of such curable resins include epoxy derivatives, oxetane derivatives, tetrahydrofuran derivatives, cyclic lactone derivatives, cyclic carbonate derivatives, cyclic imino ethers such as oxazoline derivatives, and the like, and epoxy derivatives, oxetane derivatives, and oxazoline derivatives are particularly preferable. In the present invention, the curable resin having a ring-opening polymerizable group preferably has two or more ring-opening polymerizable groups in the same molecule, more preferably three or more. In the present invention, two or more curable resins having a ring-opening polymerizable group may be used in combination. In this case, a curable resin having one ring-opening polymerizable group in the same molecule is used as necessary. Can be used together.

  The curable resin having a ring-opening polymerizable group used in the present invention is not particularly limited as long as it is a curable resin having a cyclic structure as described above. Preferred examples of such curable resins include monofunctional glycidyl ethers, monofunctional alicyclic epoxies, difunctional alicyclic epoxies, diglycidyl ethers (for example, ethylene glycol diglycidyl ether as glycidyl ethers). , Bisphenol A diglycidyl ether, trimethylol ethane triglycidyl ether), trifunctional or higher glycidyl ethers (trimethylol ethane triglycidyl ether, trimethylol propane triglycidyl ether, glycerol triglycidyl ether, triglycidyl trishydroxyethyl isocyanurate, etc. ) Tetrafunctional or higher functional glycidyl ethers (sorbitol tetraglycidyl ether, pentaerythritol tetraglycyl ether, cresol novolac resin) Liglycidyl ether, polyglycidyl ether of phenol novolac resin, etc.), cycloaliphatic epoxies (Celoxide 2021P, Celoxide 2081, Epolide GT-301, Epolide GT-401 (above, manufactured by Daicel Chemical Industries, Ltd.)), EHPE ( Daicel Chemical Industries, Ltd.), phenol novolak resin polycyclohexyl epoxy methyl ether, etc.), oxetanes (OX-SQ, PNOX-1009 (above, manufactured by Toagosei Co., Ltd.), etc.). The invention is not limited to these examples.

  A curable composition containing a curable compound containing an ethylenically unsaturated group (curable resin) and a curable resin containing a ring-opening polymerizable group (hereinafter, unless otherwise specified, the “curable composition” When curing these two curable resins), it is preferable that the crosslinking reaction of both curable resins proceeds. A preferable crosslinking reaction of the ethylenically unsaturated group is a radical polymerization reaction, and a preferable crosslinking reaction of the ring-opening polymerizable group is a cationic polymerization reaction. In either case, the polymerization reaction can be advanced by the action of active energy rays. Usually, a small amount of radical generator and cation generator (or acid generator) called polymerization initiators can be added and decomposed by active energy rays to generate radicals and cations to proceed the polymerization. . Although radical polymerization and cationic polymerization may be performed separately, it is preferable to proceed simultaneously.

Examples of photoacid generators that generate cations by ultraviolet rays include ionic curable resins such as triarylsulfonium salts and diaryliodonium salts, and nonionic curable resins such as nitrobenzyl esters of sulfonic acids. Various known photoacid generators such as curable resins described in “Electronic Materials for Imaging” (1997) published by the Electronics Materials Research Group can be used. Of these, diaryl iodonium salts are particularly preferred from the viewpoint that yellow coloring is particularly small, and PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , B (C ₆ F ₅ ) ₄ ^{− and the} like are preferable as counter ions. It is also a preferred embodiment to use a combination of triarylsulfonium salt and diaryliodonium salt.

  Examples of polymerization initiators that generate radicals by ultraviolet rays include known radical generators such as acetophenones, benzophenones, Michler's ketone, benzoylbenzoate, benzoins, α-acyloxime esters, tetramethylthiuram monosulfide, and thioxanthone. Can be used. Examples of the sensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, and thioxanthone derivatives.

  The addition amount of the polymerization initiator is 0.1 to 15% by mass with respect to the total mass of the ethylenically unsaturated group-containing curable resin and the ring-opening polymerizable group-containing curable resin contained in the curable composition. It is preferably used in a range, and more preferably in a range of 1 to 10% by mass.

In the present invention, it is preferable to add fine particles to the curable composition. By adding inorganic fine particles, swelling of the polycarbonate film can be suppressed. In addition, since the amount of cure shrinkage of the cured coating can be reduced by adding fine particles, adhesion with the substrate can be improved, and curling can be reduced when the substrate is a plastic film, which is also preferable in this respect. As the fine particles, any of inorganic fine particles, organic fine particles, and organic-inorganic composite fine particles can be used.
As the inorganic fine particles, for example, those having a high hardness are preferable, inorganic oxide particles having a Mohs hardness of 6 or more are preferable, and silicon dioxide particles, titanium dioxide particles, zirconium oxide particles, aluminum oxide particles and the like can be mentioned. Since such inorganic crosslinked fine particles are generally hard, filling the hard coat layer can not only improve shrinkage during curing but also increase the surface hardness.
However, since the fine particles generally tend to increase haze, it is necessary to adjust the filling method in consideration of the balance of each required characteristic.

Since polycarbonate has a high refractive index, reflection at the interface between the hard coat and the base film can be suppressed by setting the refractive index of the hard coat high. In this respect, titanium dioxide particles and zirconium oxide particles are preferred.
Since the silicon dioxide particles are easy to control the shape and size of the particles, they are advantageous when it is desired to control the scattering by adjusting the size of the particles or to produce particles with good dispersibility. In addition, the addition of silicon dioxide particles to the hard coat is preferable because the refractive index of the hard coat layer can be lowered and reflection on the hard coat surface can be suppressed.

Generally, inorganic fine particles have low affinity with organic components such as a polymer and a polyfunctional vinyl monomer, and therefore, by simply mixing, an aggregate may be formed or a cured film after curing may be easily cracked. In the present invention, in order to increase the affinity between the inorganic fine particles and the organic component, the surface of the inorganic fine particles can be treated with a surface modifier containing an organic segment. The surface modifier preferably has a functional group capable of forming a bond with or adsorbing to the inorganic fine particles and a functional group having high affinity with the organic component in the same molecule.
Examples of the surface modifier having a functional group capable of binding or adsorbing to inorganic fine particles include metal alkoxide surface modifiers such as silane, aluminum, titanium, and zirconium, phosphate groups, sulfate groups, sulfonate groups, carboxylic acid groups, and the like. A surface modifier having an anionic group is preferred.
Furthermore, the functional group having a high affinity with the organic component may be simply a combination of the organic component and the hydrophilicity / hydrophobicity, but a functional group that can be chemically bonded to the organic component is preferable, particularly an ethylenically unsaturated group, Or a ring-opening polymerizable group is preferable.
A preferable inorganic fine particle surface modifier in the present invention is a metal alkoxide or a curable resin having an anionic group and an ethylenically unsaturated group or an anionic group and a ring-opening polymerizable group in the same molecule.

Representative examples of these surface modifiers include the following unsaturated double bond-containing coupling agents, phosphate group-containing organic curable resins, sulfate group-containing organic curable resins, carboxylic acid group-containing organic curable resins, and the like. It is done.
_{S-1 H 2 C = C} (X) COOC 3 H 6 Si (OCH 3) 3
_{S-2 H 2 C = C} (X) COOC 2 H 4 OTi (OC 2 H 5) 3
_{S-3 H 2 C = C} (X) COOC 2 H 4 OCOC 5 H 10 OPO (OH) 2
S-4 (H ₂ C═C (X) COOC ₂ H ₄ OCOC ₅ H ₁₀ O) ₂ POOH
_{S-5 H 2 C = C} (X) COOC 2 H 4 OSO 3 H
_{S-6 H 2 C = C} (X) COO (C 5 H 10 COO) 2 H
S-7 H ₂ C═C (X) COOC ₅ H ₁₀ COOH
_{S-8 CH 2 CH (O} ) CH 2 OC 3 H 6 Si (OCH 3) 3
(X represents H or CH ₃ )

The surface modification of these inorganic fine particles is preferably performed in a solution. When inorganic fine particles are mechanically finely dispersed, a surface modifier is present together, or after finely dispersing inorganic fine particles, the surface modifier is added and stirred, or further before finely dispersing inorganic fine particles The surface may be modified (if necessary, heated, dried and then heated, or pH changed), and then finely dispersed.
As the solution for dissolving the surface modifier, an organic solvent having a large polarity is preferable. Specific examples include known solvents such as alcohols, ketones and esters.

The organic fine particles are not particularly limited, but polymer particles composed of monomers having an ethylenically unsaturated group, such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polybutyl acrylate, polyethylene, polypropylene, polystyrene In addition, polysiloxane, melamine resin, benzoguanamine resin, polytetrafluoroethylene, polycarbonate, nylon, polyvinyl alcohol, polytetrafluoroethylene, polyethylene terephthalate, polyvinyl chloride, acetylcellulose, nitrocellulose, gelatin, etc. Resin particles. These particles are preferably crosslinked.
As the fine particle disperser, it is preferable to use ultrasonic waves, dispersers, homogenizers, dissolvers, polytrons, paint shakers, sand grinders, kneaders, Eiger mills, dyno mills, coball mills, and the like. As the dispersion medium, the above-mentioned solvent for surface modification is preferably used.

  The filling amount of the fine particles is preferably 2 to 40% by volume, more preferably 3 to 30% by volume, and most preferably 5 to 20% by volume with respect to the volume of the cured film after filling.

  When a hard coat film is used for optical applications, it is preferable that the haze is low. The haze of the cured coating of the present invention is 5% or less, preferably 2% or less, and most preferably 1.0% or less.

  In the present invention, a curable composition that is cured by irradiation with an active energy ray containing an antifouling agent in these prepared cured films or a low surface energy curable resin containing fluorine and / or silicon. By laminating an antifouling layer mainly composed of, an antifouling cured film can be obtained.

  The antifouling agent used in the present invention imparts antifouling properties such as water repellency and oil repellency to a curable substrate. As such, the preparation and base of an energy ray curable resin composition can be used. Any material may be used as long as it has no inconvenience when applied on the material and exhibits water repellency and oil repellency on the surface of the cured film when the cured film is formed. Examples thereof include a cured resin containing fluorine and / or silicon. Moreover, the antifouling layer laminated on the cured coating used in the present invention can also be formed by a composition containing a curable resin containing fluorine and / or silicon.

  Examples of the curable resin containing fluorine and / or silicon contained in the cured film or antifouling layer used in the present invention include known fluorine curable resins and silicon curable resins, or blocks having fluorine and silicon-containing portions. A curable resin having a segment having good compatibility with the resin or metal oxide and a segment containing fluorine or silicon is preferable and added to the cured film or the antifouling layer. Thus, fluorine or silicon can be unevenly distributed on the surface.

Specific examples of these curable resins include block copolymers or graft copolymers of fluorine- or silicon-containing monomers with other hydrophilic or lipophilic monomers. Examples of the fluorine-containing monomer include perfluoroalkyl group-containing (meth) acrylic esters represented by hexafluoroisopropyl acrylate, heptadecafluorodecyl acrylate, perfluoroalkylsulfonamidoethyl acrylate, perfluoroalkylamidoethyl acrylate, and the like. Examples of the silicon-containing monomer include monomers having a siloxane group by a reaction such as polydimethylsiloxane and (meth) acrylic acid.
Hydrophilic or lipophilic monomers include (meth) acrylic acid esters such as methyl acrylate, hydroxyl-containing polyester and (meth) acrylic acid ester at the terminal, hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylic acid Examples include esters. In the present specification, “(meth) acrylate” and “(meth) acrylic acid” represent “acrylate or methacrylate” and “acrylic acid or methacrylic acid”, respectively.
Commercially available curable resins include acrylic oligomer defensers MCF-300, 312, 323, etc. having a perfluoroalkyl chain microdomain structure, and perfluoroalkyl group / lipophilic group-containing oligomers Megafac F-170, F -173, F-175, etc., perfluoroalkyl group / hydrophilic group-containing oligomer Megafac F-171 (Dainippon Ink Chemical Co., Ltd.), and segments with excellent surface migration and resin are compatible. Examples thereof include alkyl fluoride-based Modiper F-200, 220, 600, and 820 which are block polymers of vinyl monomers composed of segments, and silicon-based Modiper FS-700 and 710 (manufactured by NOF Corporation).

  In order to provide an antifouling layer on the cured coating, a low surface energy curable resin containing fluorine atoms is preferred. Specifically, JP-A-57-34526 and JP-A-2-19811 are preferred. And fluorinated hydrocarbon group-containing silicon curable resins and fluorinated hydrocarbon group-containing polymers described in JP-A-3-17901.

  The coating liquid for the curable composition is prepared by dissolving the above polyfunctional monomer and the polymerization initiator in a dilute organic solvent such as a ketone, alcohol or ester. Furthermore, it can be prepared by adding a surface-modified hard inorganic fine particle dispersion and a soft fine particle dispersion.

Next, the organic solvent for diluting the cured composition will be described.
In the present invention, the organic solvent having a solubility parameter (SP value) of 8.3 or more and 10.5 or less is 60% by mass or less, preferably 50% or less, as the organic solvent. Particularly preferably, an organic solvent having a composition of 40% or less is used.
The organic solvent having an SP value of 9.0 or more and 10.0 or less is preferably 20% or less, more preferably 10% or less, more preferably 5% or less in the total organic solvent in the polycarbonate film curable composition. % Or less, and most preferably not contained at all.

The solubility parameter (SP value) in the present invention is σ = [(ΔH−RT) / VL] ^1/2 (where σ: solubility parameter, ΔH: heat of evaporation, VL: molar volume, R : Represents a gas constant) ΔH is calculated from the boiling point according to the Hidebrand rule, and is a value of ΔH298 = 23.7Tb + 0.020Tb ² −2950 (where Tb: boiling point). Therefore, the solubility parameter is also a value of 298 ° K. Specific examples of solubility parameters determined by the Hidebrand rule are described in, for example, J. BRANDRUP, EHIMMERGUT, and, EAGRULKE “POLYMER HANDBOOK FORTH EDITION” VII / 688-694 (1998), JOHN WILEY & SONS, INC. Part is specifically described. The method for calculating the solubility parameter according to the Hidebrand rule is described in JHHildebrand, “Solubility of Nonelectrolytes” 424-427 (1950), Reinhold Publishing Co.
Table 1 shows the SP values of representative compounds.

According to the inventor's research, point defects generated in a functional layer formed from a curable composition are caused by the organic solvent of the composition penetrating into the polycarbonate film, causing the surface to swell unevenly, A protrusion having a size of about 10 μm to 100 μm is generated at the interface of the coating liquid. When this functional film is used as an optical film for an image display device such as a liquid crystal display, the protrusion is recognized as a point defect. An organic solvent having a solubility parameter (SP value) of 8.3 or more and 10.5 or less, particularly 9.0 or more and 10.0 or less, easily penetrates the polycarbonate film and swells the surface unevenly. The protrusions are likely to occur.
Hereinafter, the solvent which penetrates the polycarbonate film and easily swells the surface nonuniformly is referred to as a solvent (S) which attacks the polycarbonate.
That is, as the organic solvent for diluting the cured composition of the present invention, the proportion of the organic solvent (S) that attacks the polycarbonate at 25 ° C. in the total organic solvent is 60% by mass or less, preferably 50% or less, particularly preferably. May be an organic solvent having a composition of 40% or less.

Here, the judgment of whether or not to invade the polycarbonate at 25 ° C. is performed by adding a piece of polycarbonate film (1 cm × 2 cm) used as a base material on which a cured layer is to be formed in an atmosphere of 25 ° C. in 50 cc of a solvent and stirring. Observe after 5 minutes, and visually observe.
A solvent that erodes the polycarbonate film dissolves or makes the polycarbonate film cloudy. By observing the speed of dissolution or cloudiness, the degree of erosion can be assessed. In addition, those having a high degree of erosion on the polycarbonate film completely dissolve the polycarbonate film. Solvents that do not attack the polycarbonate film do not cloud the polycarbonate film and remain transparent.

[Solvents that attack polycarbonate at 25 ° C]
Examples include cyclohexanone, acetone, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, acetonitrile, toluene, ethyl acetate, methyl acetate and the like.

[Solvent that does not attack polycarbonate at 25 ° C]
For example, methanol, isopropyl alcohol, 1-propanol, ethanol, cyclohexane, 1-butanol, 1-methoxy-2-propanol and the like can be mentioned.

  As a solvent that does not attack polycarbonate at 25 ° C., in addition to the above, alcohols other than the above, pentane, n-hexane, isohexane, n-heptane, n-octane, isooctane, nonane, decane, 2-methylhexane, 3- Methylhexane, 3-methylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2,3-dimethylbutane, 2,2,3-trimethylpentane, 2,2,4 -Saturated aliphatic hydrocarbons such as trimethylpentane, 2,2,3,3-tetramethylbutane, pentene, hexene and its isomer, hexadiene and its isomer, hexatriene, heptene and its isomer, heptadiene and its isomer , Heptatriene, octene and its isomers, octadiene, octatriene, none Unsaturated aliphatic hydrocarbons such as nonadiene, nonatriene, decene, undecene, dodecene, cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, diethylcyclohexane, isopropylcyclohexane, cycloheptane, cyclopentane, methylcyclopentane, dimethylcyclopentane, Saturated alicyclic hydrocarbons such as ethylcyclopentane, diethylcyclopentane, isopropylcyclopentane, cyclooctane, cyclopentene, cyclopentadiene, cyclohexene, methylcyclohexene, dimethylcyclohexene, ethylcyclohexene, cyclohexadiene, methylcyclohexadiene, cycloheptene, etc. Unsaturated alicyclic hydrocarbons, diethyl ether, dibutyl ether, diisobuty D - ether, Jipuropirue - ether, diisopropyl et - ether, chain et such dipentyl ether - can be exemplified non-polar solvent ether type or the like.

[Coating]
The cured layer of the present invention is prepared by dipping, spinner, spraying, roll coater method, gravure method, wire bar method, slot extrusion coater method (single layer, multilayer) on a polycarbonate film substrate. It can be prepared by coating by a known thin film forming method such as a slide coater method, drying, irradiating with ultraviolet rays and curing.
Drying is preferably performed under conditions where the organic solvent concentration in the applied liquid film is 5% by mass or less after drying, more preferably 2% by mass or less, and even more preferably 1% by mass or less. The drying conditions are affected by the thermal strength of the substrate, the conveyance speed, the length of the drying process, and the like, but the one having as low an organic solvent content as possible is preferable in terms of increasing the polymerization rate.

  Moreover, when the ultraviolet curable composition which has an acrylate monomer preferably used in the present invention as a main component is irradiated with ultraviolet rays under oxygen, curing failure occurs, and scratches easily occur when rubbed with steel wool. In order to prevent this, it is necessary to lower the oxygen concentration in the ultraviolet irradiation atmosphere. The oxygen concentration at the time of irradiation is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.3% or less.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to these examples at all.

(Preparation of hard coat layer coating solution (h-1))
450 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 210 parts by mass of isopropyl alcohol (IPA) and 140 parts by mass of methyl isobutyl ketone (MIBK) Dissolved in the mixed solvent. After adding 12.0 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) to the resulting solution and stirring until dissolved, 380 parts by mass of IPA-ST (average particle size of 10 to 20 nm, solid content) 30 mass% SiO ₂ sol isopropyl alcohol dispersion (manufactured by Nissan Chemical Co., Ltd.) and 257 mass parts MIBK-ST (average particle size 10-20 nm, solid content concentration 30 mass% SiO ₂ sol methyl isobutyl) Ethyl ketone dispersion (manufactured by Nissan Chemical Co., Ltd.) was added and stirred to obtain a mixture, which was filtered through a polypropylene filter (PPE-03) having a pore size of 3 μm to obtain a hard coat layer coating solution (h-1). Prepared.

(Preparation of hard coat layer coating solutions (h-2) to (h-7))
The composition of the hard coat layer coating solution (h-1) was changed as shown in Table 2 below to prepare hard coat layer coating solutions (h-2) to (h-7).
Table 3 shows the SP values of the solvents used for preparing the hard coat layer coating solution.

* 1M2P: 1-methoxy-2-propanol * IRG907: Irgacure 907, manufactured by Ciba Geigy * MEK-ST: Dispersion of methyl ethyl ketone in SiO ₂ sol having an average particle size of 10 to 20 nm and a solid content concentration of 30% by mass, Nissan Chemical Co., Ltd. ) Made * S ratio: The content of the solvent in which the SP value is in the range of 8.3 to 10.5 in the total solvent, and the content of the solvent (S) invading the polycarbonate film in the total solvent.

(Preparation of hard coat film)
Example 1
The coating speed is set to 10 m / min, and the thickness after drying the hard coat coating solution is 3.3 μm on a polycarbonate film (Pure Ace 110-80 manufactured by Teijin Chemicals Ltd.) having a width of 500 mm and a thickness of 80 mm. It applied using a bar coater so that a width | variety might be set to 480 mm, and after drying for 1 minute at 70 degreeC, the ultraviolet-ray was irradiated, the hard-coat layer was hardened, and the hard-coat film was wound up 30m.

Example Samples 2 to 6 and Comparative Samples 1 to 6 were prepared by changing the hard coat solution, film thickness, substrate, or process conditions as described in Example 1 as follows.
In Comparative Examples 2 and 3, a triacetyl cellulose film (TD-80UF, manufactured by Fuji Photo Film Co., Ltd.) having a film thickness of 80 μm was used.

(Evaluation of hard coat film)
(1) Evaluation of point defect The center part 10cmx10cm of the produced hard coat film was cut out, the back surface was black-coated, and it magnified 30 times with the actual microscope, and counted the number of point defects.
(2) Steel wool scratch resistance evaluation A rubbing test was performed under the following conditions using a rubbing tester.
Sample humidity control conditions: 25 ° C., 60% RH, 2 hours or more.
Rubbing material: Steel wool (Nippon Steel Wool, Gelade No. 0000) was wound around the rubbing tip (1 cm × 1 cm) of a tester in contact with the sample, and the band was fixed so as not to move.
Moving distance (one way): 13 cm, rubbing speed: 13 cm / sec, load: 200 g / cm ² , tip contact area: 1 cm × 1 cm, rubbing frequency: 2 reciprocations.
Oily black ink was applied to the back side of the rubbed sample and visually observed with reflected light, and scratches on the rubbed part were evaluated in two stages according to the following criteria.
I can't see the wound. : ○
I see scratches. : ×

From the results shown in Tables 2 to 4, the following is clear.
The hard coat layer curable composition prepared only with an organic solvent having an SP value of 8.3 or more and 10.5 or less (which corrodes the polycarbonate film), and the hard coat layer formed on the polycarbonate film is derived from the polycarbonate film. Many point defects occur (Comparative Examples 4 to 7).
The number of point defects caused by polycarbonate can be reduced by reducing the ratio of the organic layer agent that attacks the polycarbonate film to 60% or less (comparison between Examples 1 to 6 and Comparative Examples 4 to 7). .
Although the SP value is 9.0 or more and 10.0 or less, the number of point defects caused by the polycarbonate can be reduced by reducing the ratio in the total organic solvent to zero (comparison of Examples 3 and 4). .
Although the SP value is 9.0 or more and 10.0 or less, when the ratio in the total organic solvent that corrodes the polycarbonate film is reduced to 40% after the ratio in the total organic solvent is reduced to zero, the point resulting from the polycarbonate Defects can be nearly zero (Examples 1, 2, 5 and 6).
The point defects caused by the polycarbonate generated by the organic solvent attacking the polycarbonate film can be gradually reduced by increasing the cured film thickness to 2.2 to 4.4 μm (Comparative Examples 4, 5, and 6).
By including inorganic oxide fine particles in the curable composition, the number of point defects can be reduced (Comparison between Comparative Examples 6 and 7).

[Application to image display devices]
A liquid crystal display device (6E-A3) using a TN type liquid crystal cell with an acrylic adhesive on the opposite side of the hard coat layer with the hard coat film shown in Example 1 and Comparative Example 4 produced above cut into 10 cm squares. , Manufactured by Sharp Corporation) so as to have a symmetrical positional relationship from the center.
When the hard coat film of Comparative Example 4 was used, a point defect portion appeared to glitter on the surface, but when the hard coat film of Example 1 was used, the image was clearly visible.
The place where the hard coat sample was pasted was rubbed with the steel wool where the two hard coat samples of Comparative Example 4 and Example 2 were pasted together and the part where nothing was pasted. It was not scratched.
From the above results, the hard coat film of the present invention is also suitable as a protective film for an image display device.

[Application to optical recording disks]
(Production of optical recording disk)
Example 1 described in paragraphs [0052] to [0059] of Japanese Patent Application Laid-Open No. 2003-26396 was used as Comparative Example 20 of the present invention, and the cover film described in [0057] (polycarbonate film, Teijin Pure Ace, Thickness: 80 μm, with a second release film on one side; surface roughness of surface D of the second release film, 250 nm) In place of the hard coat films of Example 1 and Comparative Example 4 shown above Thus, optical recording bodies (optical recording disks) were obtained (Example 21 and Comparative Example 24, respectively).

(Sample evaluation)
(1) Evaluation of noise Paragraph [0060] <Evaluation> in JP-A-2003-26396 (Evaluation) (1) When Example 21 and Comparative Example 24 were evaluated according to C / N (carrier-to-noise ratio), point defects Was detected as noise, and it was confirmed that noise can be greatly reduced by the present invention.
(2) Scratch resistance Evaluation to the extent that scratches are visible when the surface of the light-transmitting layer side of the sample is rubbed while applying a load of 200 g using steel steel of # 0000 (○ is rubbed 100 times) In the state where no trace was visible, x was a state where the trace was visible less than 30 times). However, the following results were obtained.
Example 21: ○ Comparative Example 20: ×
Comparative Example 24: From the above results, it can be seen that the hard coat film of the present invention has less noise and is resistant to scratches, and is therefore suitable as a protective film for optical recording disks.

Claims (12)

  A curable composition for a transparent polycarbonate film substrate containing a curing agent and an organic solvent, wherein an organic solvent having a solubility parameter (SP value) of 8.3 or more and 10.5 or less is contained in all organic solvents. A curable composition for a polycarbonate film, wherein the ratio is 60% by mass or less.   The curable composition for a polycarbonate film according to claim 1, wherein the solubility parameter (SP value) does not include an organic solvent having a viscosity of 9.0 or more and 10.0 or less.   A curable composition for a transparent polycarbonate film substrate containing a curing agent and an organic solvent, wherein the proportion of the solvent (S) that attacks the polycarbonate film at 25 ° C. is 60% by mass. The curable composition for polycarbonate films characterized by the following.   The curable composition for a polycarbonate film according to claim 3, wherein the solubility parameter (SP value) of the solvent (S) that corrodes the polycarbonate film is 8.3 or more and 10.5 or less.   The curable composition for a polycarbonate film according to any one of claims 1 to 4, comprising 2 to 40% by volume of the inorganic oxide fine particles with respect to the cured film after filling.   6. The polycarbonate film according to claim 5, wherein the inorganic fine particles are inorganic fine particles containing a dispersion of at least one inorganic oxide selected from silicon oxide, titanium oxide, zirconium oxide and aluminum oxide. Curable composition.   A functional film obtained by directly laminating a functional layer formed by curing the curable composition for polycarbonate according to claim 1 on a polycarbonate film substrate.   The functional film according to claim 7, wherein the functional layer has a thickness of 2.5 μm to 4.0 μm.   The functional film according to claim 7 or 8, wherein the functional layer is a hard coat layer having scratch resistance by steel wool.   The functional layer is formed by applying and curing the curable composition according to any one of claims 1 to 6 on a polycarbonate film substrate, according to any one of claims 7 to 9. A method for producing a functional film.   The image display apparatus carrying the functional film in any one of Claims 7-9.   An optical recording disk on which the functional film according to claim 7 is mounted.