JP7185471B2 - Hard coat film and its manufacturing method - Google Patents

Description

The present invention relates to a hard coat film used for optical members and a method for producing the same. More specifically, it relates to a hard coat film that can be used as a protective film for display device parts such as panel displays such as electroluminescence (EL) displays, liquid crystal displays (LCDs) and plasma displays, and touch panels.

For example, the display surface of a liquid crystal display such as a liquid crystal display (LCD) is required to be scratch-resistant so as not to be scratched during handling and reduce visibility. Therefore, a hard coat film obtained by providing a hard coat layer on a base film is generally used to impart scratch resistance to the display surface of the display. In recent years, with the spread of touch panels that allow data and instructions to be input by touching with a finger, pen, etc. while viewing the display on the display screen, functional demands for hard coat films used in such optical members are increasing.

By the way, the cycloolefin polymer film is excellent in transparency, heat resistance, dimensional stability, low hygroscopicity, low birefringence, and optical isotropy as a base film. is expected, and it has been proposed to provide a hard coat layer on this cycloolefin film. However, unlike acrylic films and polyester films, this cycloolefin polymer film has a small number of polar groups on the film surface, so when a cycloolefin polymer film is used as a substrate, the adhesion to the hard coat layer is poor. there was a point
Therefore, conventionally, methods for imparting easy adhesion to a hard coat layer to a cycloolefin polymer film have been disclosed in Patent Documents 1 and 2, and the like.

Japanese Patent Application Laid-Open No. 2001-147304 JP 2006-110875 A

Conventionally, as a method for imparting easy adhesion to a hard coat layer to a cycloolefin polymer film, Patent Document 1 discloses corona treatment, plasma treatment, ultraviolet irradiation treatment, etc. In these methods, cycloolefin There is a problem that the adhesion between the polymer film and the hard coat layer is insufficient.

Further, Patent Document 2 discloses a method of applying an anchor coating agent made of an olefin-based resin onto a cycloolefin polymer film. Although this anchor coat treatment improves the adhesion between the cycloolefin polymer film and the hard coat layer to some extent, it is still insufficient. Furthermore, there is also a problem that cracks tend to occur on the surface of the hard coat layer under heat-resistant conditions. Even if such a specific material is used for anchor coating, the adhesion between the base film and the hard coat layer is not sufficiently improved.
Therefore, in conventional hard coat films, improvement of adhesion to the hard coat layer when using a cycloolefin polymer film as a base material has been a major issue.

Accordingly, an object of the present invention is to provide a hard coat film which uses a cycloolefin polymer film as a base material and is particularly excellent in adhesion to the hard coat layer, and a method for producing the same.

The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have found that the adhesion to the hard coat layer can be improved by using a specific resin for the primer layer.
That is, the present invention has the following configurations in order to solve the above problems.

(First invention)
A hard coat film in which a hard coat layer containing an ionizing radiation-curable resin is laminated via a primer layer on at least one side of a cycloolefin polymer base film, wherein the primer layer comprises a polyolefin resin having α , β-unsaturated carboxylic acid or a derivative thereof, and a modified polyolefin resin graft-modified with a (meth)acrylic acid ester, and when the modified polyolefin resin is 100% by weight, the α, β - A hard coat film, wherein the graft weight of the unsaturated carboxylic acid or its derivative is in the range of 0.4 to 7% by weight, and the glass transition point is in the range of -30°C to -10°C.

(Second invention)
The hard coat film according to the first invention, wherein the polyolefin resin is a propylene-ethylene copolymer.

(Third invention)
The α,β-unsaturated carboxylic acid or derivative thereof includes maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, hymic anhydride. The hard coat film according to the first or second invention, which is one or more compounds selected from acid and (meth)acrylic acid.

(Fourth invention)
Any one of the first to third inventions, wherein the hard coat layer contains, as the ionizing radiation-curable resin, a polyfunctional acrylate having three or more (meth)acryloyloxy groups in one molecule. The hard coat film described in .

(Fifth invention)
A method for producing a hard coat film having a hard coat layer containing an ionizing radiation-curable resin on a cycloolefin polymer base film via a primer layer, comprising: A polyolefin resin is graft-modified with an α,β-unsaturated carboxylic acid or a derivative thereof and a (meth)acrylic acid ester, and the α,β-unsaturated carboxylic acid when the modified polyolefin resin is 100% by weight. Or a primer layer coating containing a modified polyolefin resin having a graft weight of a derivative thereof in the range of 0.4 to 7% by weight and a glass transition point in the range of -30°C to -10°C is applied. , dry to form a primer layer, then apply a hard coat layer coating containing an ionizing radiation-curable resin on the primer layer, dry to form a hard coat layer, and then apply ionizing radiation. A method for producing a hard coat film, characterized by:

(Sixth invention)
The method for producing a hard coat film according to the fifth invention, wherein the polyolefin resin is a propylene-ethylene copolymer.

(Seventh invention)
The α,β-unsaturated carboxylic acid or derivative thereof includes maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, hymic anhydride. The method for producing a hard coat film according to the fifth or sixth invention, wherein the compound is one or more compounds selected from acid and (meth)acrylic acid.

According to the present invention, it is possible to obtain a hard coat film which is particularly excellent in adhesion to the hard coat layer by using a cycloolefin polymer film as a substrate.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments for carrying out the present invention will be described in detail below, but the present invention is not limited to the following embodiments.
In this specification, "○○ to △△" shall mean "○○ or more and △△ or less" unless otherwise specified.

As described in the first invention, the hard coat film of the present invention is obtained by laminating a hard coat layer containing an ionizing radiation-curable resin on at least one side of a cycloolefin polymer base film via a primer layer. A hard coat film, wherein the primer layer contains a modified polyolefin resin in which the polyolefin resin is graft-modified with an α,β-unsaturated carboxylic acid or a derivative thereof and a (meth)acrylic acid ester, When the modified polyolefin resin is 100% by weight, the graft weight of the α,β-unsaturated carboxylic acid or derivative thereof is in the range of 0.4 to 7% by weight, and the glass transition point is -30°C. It is characterized by being in the range of -10°C.
The structure of this hard coat film will be described in detail below.

[Base film]
First, the base film of the hard coat film will be described.
In the present invention, a cycloolefin polymer film having excellent transparency, heat resistance, dimensional stability, low hygroscopicity, low birefringence, optical isotropy and the like is used as the base film of the hard coat film. Specifically, cycloolefin units are alternately or randomly polymerized in the polymer skeleton and have an alicyclic structure in the molecular structure, and are norbornene compounds, monocyclic cyclic olefins, cyclic conjugated dienes and vinyl alicyclic compounds. A cycloolefin copolymer film or a cycloolefin polymer film, which is a copolymer containing at least one compound selected from cyclic hydrocarbons, is targeted, and either one can be appropriately selected and used.

In the present invention, the thickness of the cycloolefin polymer-based film is appropriately selected depending on the application. preferably 20 μm to 200 μm.

In addition, regarding the heat resistance of the cycloolefin polymer film, when it is used for a hard coat film, a thermogravimetry (TG) method or differential scanning calorimetry that measures the thermal change when a temperature change is applied to the sample. It is preferable to use a film having a glass transition temperature of about 120° C. to 170° C. as measured by a (DSC) method or the like.

In the present invention, when a hard coat layer is formed on one side of the cycloolefin polymer film via a primer layer, the back surface of the cycloolefin polymer film on which the hard coat layer is not formed is coated with a cycloolefin polymer film. Polyethylene resins and polypropylene that have excellent releasability from the cycloolefin polymer film by co-extrusion when forming the cycloolefin polymer film, for the purpose of preventing pressure adhesion during removal and improving the running performance of the film when forming the hard coat layer. A film in which a resin or a polyester resin is laminated as a protective layer may be used. Moreover, it is also possible to use the thing which stuck protective films, such as a polyethylene resin, a polypropylene resin, or a polyester resin, in which the weak adhesive layer is formed in the back surface.

Examples of the cycloolefin polymer-based film include commercially available Zeonor (trade name: manufactured by Nippon Zeon Co., Ltd.), Optica (trade name: manufactured by Mitsui Chemicals, Inc.), Arton (trade name: manufactured by JSR Corporation), Kozek (trade name: manufactured by Kurashiki Boseki Co., Ltd.) and the like.

[Primer layer]
Next, the primer layer of the hard coat film will be described.
In the hard coat film of the present invention, the primer layer contains a modified polyolefin resin in which the polyolefin resin is graft-modified with an α,β-unsaturated carboxylic acid or a derivative thereof and a (meth)acrylic acid ester. In this modified polyolefin resin, the graft weight of the α,β-unsaturated carboxylic acid or derivative thereof is in the range of 0.4 to 7% by weight when the modified polyolefin resin is 100% by weight, and , it is important that the glass transition point is in the range of -30°C to -10°C.

In the hard coat film of the present invention, a primer layer is used between the base film and the hard coat layer, and the primer layer contains the above modified polyolefin resin, and the modified polyolefin resin is α,β- The graft weight of the unsaturated carboxylic acid or its derivative is within a specific range, and the glass transition point is within a specific range. can improve the adhesion of.

The above-mentioned modified polyolefin-based resin has good adhesion to both as a primer layer between polypropylene, which is a low-polarity base material, and a topcoat layer whose main component is a high-polarity resin such as acrylic resin or urethane resin. It is known that The base film (cycloolefin polymer-based film) of the present invention is an olefin-based low-polarity base like polypropylene, and the hard coat layer is mainly composed of a highly polar acrylic resin. The modified polyolefin resin is considered suitable as a primer layer resin between the base film and the hard coat layer.

The main component resin constituting the primer layer in the present invention is a modified polyolefin resin obtained by graft-modifying a polyolefin resin with an α,β-unsaturated carboxylic acid or a derivative thereof and a (meth)acrylic acid ester. .

The above polyolefin resin (hereinafter sometimes simply referred to as "component (A)") is preferably a copolymer type polyolefin resin, for example, propylene-ethylene copolymer, propylene-1-butene copolymer α-olefin copolymer type polypropylene such as propylene-1-pentene copolymer, propylene-1-hexene copolymer and the like.

Among these, a propylene-ethylene copolymer (a copolymer mainly composed of a propylene component and an ethylene component) is preferable, and the ratio (% by weight) of the propylene component and the ethylene component in this case is determined from the viewpoint of adhesion of the hard coat layer. Therefore, the propylene component/ethylene component ratio is preferably in the range of 60/40 to 92/8, and particularly preferably in the range of propylene component/ethylene component ratio of 85/15 to 90/10.

In the present invention, the copolymer-type polyolefin resin is not limited to the above-exemplified copolymer consisting of two components. For example, it may be a three-component copolymer containing, for example, a butene component as a copolymer component other than the propylene component and the ethylene component.

The ratio of each component (copolymerization component) in the copolymerized polyolefin resin can be determined by ¹ H-NMR (proton nuclear magnetic resonance) analysis at 120° C. using ortho-dichlorobenzene (d ₄ ) as a measurement solvent. It is possible to measure
A copolymerized polyolefin resin as component (A) can be obtained by a known synthesis method.
In addition, in the present invention including the examples described later, the ratio of each component in the copolymerized polyolefin resin as the component (A) refers to the value measured by the above measuring method.

In addition, the above α,β-unsaturated carboxylic acid or derivative thereof (hereinafter sometimes simply referred to as "component (B)") includes maleic acid, maleic anhydride, fumaric acid, citraconic acid, and citracone anhydride. Examples include acids, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, hymic anhydride, (meth)acrylic acid, etc. Maleic anhydride is particularly preferred. One or more compounds selected from these compounds may be used, and in this case, a combination of one or more α,β-unsaturated carboxylic acids and one or more derivatives of α,β-unsaturated carboxylic acids. good too.

The present inventors found that when the modified polyolefin resin is 100% by weight, by using the modified polyolefin resin in which the graft weight of the component (B) is 0.4 to 7% by weight for the primer layer, It has been found that the adhesiveness to the hard coat layer can be further improved when the cycloolefin polymer film is used as the base material. The graft weight of component (B) affects the degree of acid (unsaturated carboxylic acid) modification of the resulting modified polyolefin resin.

In addition, the graft weight of the component (B) in the modified polyolefin resin is preferably in the range of 0.4 to 7% by weight when the modified polyolefin resin is 100% by weight, and more Preferably, it ranges from 0.6 to 6.5% by weight. When the graft weight of component (B) is 0.4% by weight or more, it is possible to improve the adhesion to the hard coat layer by using the resulting modified polyolefin resin in the primer layer. Moreover, since the graft weight of the component (B) is 7% by weight or less, generation of a large amount of unreacted graft material can be suppressed. The graft weight % of the component (B) is the percentage of the component (B) unit actually grafted to the polymer chain when the modified polyolefin resin is 100% by weight.

The graft weight % of component (B) can be measured by a known method. For example, it can be determined by alkaline titration or Fourier transform infrared spectroscopy.

In addition, the above (meth)acrylic acid ester (hereinafter sometimes simply referred to as "component (C)") is an ester of acrylic acid or methacrylic acid, such as methyl (meth)acrylate, ethyl (meth)acrylate, ) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, hydroxyethyl (meth) acrylate, isobornyl (meth) acrylate, glycidyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl ( meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate Acrylate, N,N-dimethylaminoethyl (meth)acrylate, acetoacetoxyethyl (meth)acrylate and the like.

The component (C) preferably contains a (meth)acrylic acid ester represented by the following general formula (I), more preferably a (meth)acrylic acid ester represented by the following general formula (I).
_CH2 = _{CR1COOR2 (} I)

In general formula (I), R ₁ represents a hydrogen atom or a methyl group, preferably a methyl group. R ₂ represents -C _n H _2n+1 . Here, n represents an integer of 8-18, preferably an integer of 8-15, more preferably an integer of 8-14, and even more preferably an integer of 8-13. Lauryl (meth)acrylate and octyl (meth)acrylate are preferable, and lauryl methacrylate and octyl methacrylate are more preferable as the (meth)acrylic acid ester represented by the general formula (I).

This suppresses the generation of the homopolymer of component (C) when synthesizing the above-mentioned modified polyolefin resin, and the polyolefin resin (component (A)), component (B), and component (C). Since a highly efficient graft reaction can be realized between them, the solvent solubility of the resulting modified polyolefin resin, the low-temperature stability of the solution, and the like can be improved. The (meth)acrylic acid ester represented by the general formula (I) can be used singly or in combination of a plurality of kinds in an arbitrary ratio.

The graft weight of the component (C) in the modified polyolefin resin is preferably in the range of 0.1 to 10% by weight, more preferably in the range of 100% by weight of the modified polyolefin resin. , in the range of 0.5 to 7% by weight. When the grafting weight of the component (C) is 0.1% by weight or more, a highly efficient grafting reaction can be achieved, so solvent solubility, low-temperature stability of the solution, etc. can be maintained satisfactorily. . In addition, the introduction of polar sites into the polymer contributes to the improvement of adhesion to the hard coat layer. Further, when the graft weight of the component (C) is 10% by weight or less, it is possible to prevent the generation of graft unreacted matter. The graft weight % of the component (C) is the percentage of the component (C) unit actually grafted to the polymer chain when the modified polyolefin resin is 100% by weight.

The graft weight % of component (C) can be measured by a known method. For example, it can be determined by Fourier transform infrared spectroscopy or ¹ H-NMR (proton nuclear magnetic resonance) analysis.

In the present invention, a graft component other than the components (B) and (C) may be used in combination as long as the effect of the present invention is not impaired. Usable graft components include, for example, (meth)acrylic acid, (meth)acrylic acid derivatives other than component (C) (e.g., N-methyl (meth)acrylamide, hydroxyethyl (meth)acrylamide, (meth)acryloyl morpholine, etc.). The graft components other than the components (B) and (C) in the modified polyolefin resin of the present invention may be used alone or in combination of multiple types. It is preferred that the total graft weight of the graft components other than C) does not exceed the total graft weight of components (B) and (C).

The modified polyolefin resin of the present invention can be obtained by graft polymerizing at least the above components (B) and (C) to the above polyolefin resin (component (A)). The method for synthesizing this modified polyolefin resin can be carried out by a known method, and a radical generator (hereinafter sometimes simply referred to as "component (D)") may be used during production. good. For example, a solution method in which a mixture of components (A), (B) and (C) is heated and dissolved in an organic solvent such as toluene, and component (D) is added thereto, or a Banbury mixer, kneader, extruder, etc. A method of adding components (A), (B), (C) and (D) using a kneader of No. 1 and subjecting them to a melt-kneading reaction under heating to obtain a modified polyolefin resin. In the latter method, components (A), (B), (C) and (D) may be added all at once or sequentially.

The radical generator as the component (D) can be appropriately selected from known radical generators, but organic peroxide compounds are particularly preferred. Examples of the organic peroxide compound include di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, benzoyl peroxide, dilauryl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, Peroxide, 1,4-bis[(t-butylperoxy)isopropyl]benzene, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-bis(t- butylperoxy)-cyclohexane, cyclohexanone peroxide, t-butylperoxybenzoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy- 2-ethylhexanoate, t-butylperoxyisopropyl carbonate, cumylperoxyoctoate, etc., among which di-t-butylperoxide, dicumylperoxide and dilaurylperoxide are preferred. Component (D) may be a single radical generator or a combination of multiple radical generators.

The amount of component (D) added in the graft polymerization reaction is preferably 1 to 100% by weight, more preferably 1 to 100% by weight of the total (weight) of the amount of component (B) and the amount of component (C) added. , 10 to 50% by weight. Sufficient grafting efficiency can be maintained by adding the component (D) in an amount of 1% by weight or more. Further, when the amount of component (D) added is 100% by weight or less, it is possible to prevent a decrease in the weight average molecular weight (Mw) of the modified polyolefin resin.

In the present invention, the weight average molecular weight (Mw) of the modified polyolefin resin used for the primer layer is preferably in the range of 40,000 to 150,000. When the modified polyolefin resin has a weight average molecular weight (Mw) of 40,000 or more, it is possible to improve adhesion to the hard coat layer by using this modified polyolefin resin in the primer layer. Further, when the weight average molecular weight (Mw) of the modified polyolefin resin is 150,000 or less, sufficient solvent solubility can be obtained.

In the present invention, the weight average molecular weight (Mw) of the modified polyolefin resin is measured by gel permeation chromatography (GPC) (standard material: polystyrene) and is a calculated value.

Further, the modified polyolefin resin of the present invention preferably has a melting point (Tm) in the range of 60°C to 90°C. Since the modified polyolefin resin has a melting point (Tm) of 60° C. or higher, it is possible to improve adhesion to the hard coat layer by using this modified polyolefin resin in the primer layer. Further, when the melting point (Tm) of the modified polyolefin resin exceeds 90° C., the film-forming property is deteriorated when the modified polyolefin resin is used as a primer layer coating material to form a coating film on a substrate film. Therefore, the melting point (Tm) of the modified polyolefin resin is preferably 90° C. or less.

In the present invention, the melting point (Tm) of the modified polyolefin resin can be measured using a differential scanning calorimeter (DSC) under conditions conforming to JIS K7121-1987. Specifically, Tm can be measured, for example, as follows.

In accordance with JIS K7121-1987, using a DSC measuring device (manufactured by Seiko Electronics Industry Co., Ltd.), about 5 mg of the sample was heated at 150 ° C. for 10 minutes and kept in a melted state, then the temperature was lowered at a rate of 10 ° C./min to -50. C., then the temperature is further raised to 150.degree. C. at a rate of 10.degree.

Further, the modified polyolefin resin of the present invention preferably has a glass transition point (Tg) in the range of -30°C to -10°C. As described above, the present inventors found that when the modified polyolefin resin is 100% by weight, the graft weight of the α,β-unsaturated carboxylic acid or derivative thereof is in the range of 0.4 to 7% by weight. and the glass transition point (Tg) of the obtained modified polyolefin resin is in the range of -30 ° C. to -10 ° C., so that by using this modified polyolefin resin in the primer layer, cycloolefin polymer It has been found that the adhesiveness to the hard coat layer can be further improved when the system film is used as the base material. Since the modified polyolefin resin has a glass transition point (Tg) of −10° C. or lower, it is possible to improve adhesion to the hard coat layer by using this modified polyolefin resin in the primer layer. Further, if the modified polyolefin resin has a glass transition point (Tg) of less than −30° C., when this modified polyolefin resin is used as a primer layer paint, the primer layer coating formed on the base film is too soft, cracks tend to occur in the hard coat layer laminated on the primer layer, so the glass transition point (Tg) is preferably −30° C. or higher.

In the present invention, the glass transition point (Tg) of the modified polyolefin resin refers to a numerical value obtained by measuring under conditions conforming to JIS K7121-1987 using a differential scanning calorimeter (DSC). do. Specifically, for example, it can be carried out under the following conditions.
In accordance with JIS K7121-1987, using a DSC measuring device (manufactured by Seiko Electronics Industry Co., Ltd.), about 5 mg of the sample was heated at 150 ° C. for 10 minutes and kept in a melted state, then the temperature was lowered at a rate of 10 ° C./min to -50. C., the temperature is further raised to 150.degree. C. at a rate of 10.degree.

In the present invention, the above specific modified polyolefin resin is used as the resin constituting the primer layer, but other resins such as styrene acrylic resin, methyl methacrylate resin, etc. are used as long as the effect of the present invention is not impaired. , acrylic resins, epoxy resins, isocyanate resins, cellulose resins, etc. may be used in combination.

This primer layer may contain inorganic or organic fine particles from the viewpoint of preventing blocking between film surfaces.
Examples of inorganic fine particles include fine particles of alumina, zinc oxide, silica, titanium oxide, cerium oxide, etc. Examples of organic fine particles include fine particles of acryl, melamine-formaldehyde condensate, polyethylene, styrene acryl, polyester, and the like. can be exemplified. As for the particle size, it is preferable to use fine particles having a particle size of, for example, 0.05 μm to 0.20 μm.

In addition, the primer layer can be blended with a leveling agent for the purpose of adjusting the surface characteristics and improving the coatability. Known leveling agents can be used. The blending amount is appropriately determined according to, for example, adjustment of surface properties and coatability.

In addition, as other additives added to the primer layer, an ultraviolet absorber, an antifoaming agent, an antifouling agent, an antioxidant, an antistatic agent, a light stabilizer, etc. are necessary within a range that does not impair the effects of the present invention. may be blended according to

The coating thickness of the primer layer in the present invention is not particularly limited, but it is 0.00 within a range that does not adversely affect the adhesion between the base film and the hard coat layer, or the pencil hardness of the hard coat layer. A range of 1 μm to 5.0 μm is preferred. The coating thickness of the primer layer can be measured by actual measurement with a micrometer.

In the present invention, the primer layer is a paint (primer layer) prepared by dissolving and dispersing inorganic or organic fine particles, leveling agents, other additives, etc. in a suitable organic solvent, if necessary, in the resin forming the primer layer. coating) is applied onto the cycloolefin polymer film (base film) and dried. The organic solvent in this case can be appropriately selected according to the solubility of the resin to be contained, and must be a solvent capable of uniformly dissolving or dispersing at least the solid content (resin, other additives), and at the time of coating From the viewpoint of workability and drying property, it is preferable to use an organic solvent having a boiling point of 50° C. to 160° C., for example. Examples of such organic solvents include aromatic solvents such as toluene, xylene and n-heptane; aliphatic solvents such as cyclohexane, methylcyclohexane and ethylcyclohexane; methyl acetate, ethyl acetate, propyl acetate and isopropyl acetate; Ester solvents such as butyl acetate and methyl lactate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol and butanol; It is also possible to use the solvent singly or in combination of several kinds.

In the present invention, methods for applying the primer layer coating material onto the base film include gravure coating, micro gravure coating, fountain bar coating, slide die coating, slot die coating, and screen printing. , a known coating method such as a spray coating method. The paint applied on the cycloolefin polymer film is usually dried at a temperature of about 50 to 120°C to remove the solvent while appropriately adjusting the drying conditions (temperature in the drying oven, wind speed in the oven, drying time, etc.). to form a coating film.

[Hard coat layer]
Next, the hard coat layer of the hard coat film will be described.
In the present invention, the resin contained in the hard coat layer is not particularly limited as long as it is a resin that forms a film. In addition, it is preferable to use an ionizing radiation-curable resin because the degree of cross-linking can be adjusted by adjusting the amount of exposure to ultraviolet rays, and the surface hardness of the hard coat layer can be adjusted.

The ionizing radiation curable resin used in the present invention is a transparent resin that is cured by irradiation with ultraviolet rays (hereinafter abbreviated as "UV") or electron beams (hereinafter abbreviated as "EB"). , Although not particularly limited, UV or EB having 3 or more (meth)acryloyloxy groups in one molecule for coating film hardness and hard coat layer to form a three-dimensional crosslinked structure A curable polyfunctional acrylate is preferred. Specific examples of UV- or EB-curable polyfunctional acrylates having three or more (meth)acryloyloxy groups in the molecule include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra (meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane ethoxy triacrylate, glycerin propoxy Triacrylate, ditrimethylolpropane tetraacrylate and the like can be mentioned. The polyfunctional acrylates may not only be used alone, but may also be used in combination of two or more.

Furthermore, the ionizing radiation curable resin used in the present invention preferably uses a polymer having a weight average molecular weight (Mw) in the range of 700 to 3600, more preferably a weight average molecular weight in the range of 700 to 3000. An average molecular weight of 700-2400 is more preferred. When the weight-average molecular weight is less than 700, curing shrinkage when cured by UV or EB irradiation is large, and the phenomenon (curling) in which the hard coat film is warped toward the hard coat layer side becomes large. Defects occur and processing aptitude is poor. On the other hand, if the weight average molecular weight exceeds 3600, the flexibility of the hard coat layer is increased, but the hardness is insufficient, which is not suitable.

When the ionizing radiation-curable resin used in the present invention has a weight average molecular weight of less than 1,500, the number of functional groups per molecule is desirably 3 or more and less than 10. Further, when the weight average molecular weight of the ionizing radiation-curable resin is 1500 or more, the number of functional groups in one molecule is desirably 3 or more and 20 or less. Within the above range, it is possible to suppress the occurrence of cracks under heat-resistant conditions (storage at 100° C. for 5 minutes), suppress curling, and maintain suitable workability.

In addition to the ionizing radiation-curable resins described above, the resins contained in the hard coat layer include thermoplastic resins such as polyethylene, polypropylene, polystyrene, polycarbonate, polyester, acrylic, styrene-acrylic, cellulose, and phenol. Thermosetting resins such as resins, urea resins, unsaturated polyesters, epoxies, silicone resins, etc. may be blended within a range that does not impair the hardness and scratch resistance of the hard coat layer.

It is also possible to further improve the surface hardness (scratch resistance) by incorporating inorganic oxide fine particles into the hard coat layer. In this case, the average particle size of the inorganic oxide fine particles is preferably in the range of 5 to 50 nm, more preferably in the range of 10 to 20 nm. If the average particle size is less than 5 nm, it is difficult to obtain sufficient surface hardness. On the other hand, if the average particle size exceeds 50 nm, the glossiness and transparency of the hard coat layer are likely to be reduced, and the flexibility may also be reduced.

In the present invention, examples of the inorganic oxide fine particles include alumina and silica. Among these, alumina containing aluminum as a main component is particularly suitable because it has high hardness and can be effective with a smaller addition amount than silica.

In the present invention, the content of the inorganic oxide fine particles is preferably 0.1 to 10.0 parts by weight with respect to 100 parts by weight of the ionizing radiation-curable resin of the hard coat layer 3 . If the content of the inorganic oxide fine particles is less than 0.1 parts by weight, it is difficult to obtain the effect of improving the surface hardness (scratch resistance). On the other hand, when the content exceeds 10.0 parts by weight, the haze increases, which is not preferable.

The hard coat paint for forming the hard coat layer may contain a photopolymerization initiator. Such photoinitiators include commercially available acetophenones such as Omnirad 651 and Omnirad 184 (both trade names: manufactured by IGM Resins), and benzophenones such as Omnirad 500 (trade name: manufactured by IGM Resins). can be used.

A leveling agent can be used in the hard coat layer for the purpose of improving coatability. For example, known leveling agents such as fluorine-based, acrylic-based, siloxane-based, and adducts or mixtures thereof can be used. is. The blending amount can be in the range of 0.03 to 3.0 parts by weight per 100 parts by weight of the solid content of the resin of the hard coat layer. In addition, in touch panel applications, etc., it is required to have anti-adhesiveness using an optically transparent adhesive OCR for the purpose of bonding with the cover glass (CG) of the touch panel terminal, the transparent conductive member (TSP), the liquid crystal module (LCM), etc. In some cases, it is preferable to use an acrylic leveling agent or a fluorine-based leveling agent with a high surface free energy (approximately 40 mN/m or more).

Other additives to be added to the hard coat layer include ultraviolet absorbers, antifoaming agents, surface tension modifiers, antifouling agents, antioxidants, antistatic agents, and light stabilizers, as long as they do not impair the effects of the present invention. You may mix|blend an agent etc. as needed.

The hard coat layer is prepared by dissolving and dispersing a photopolymerization initiator, other additives, etc. in an appropriate solvent in addition to the above-described ionizing radiation curable resin, applying a hard coat paint on the primer layer, and drying. Then, by irradiating ionizing radiation such as UV or EB, photopolymerization occurs and a hard coat layer having excellent hard properties can be obtained. The solvent can be appropriately selected according to the solubility of the resin to be blended, and any solvent that can uniformly dissolve or disperse at least the solid content (resin, photopolymerization initiator, other additives, etc.) may be used. Examples of such solvents include aromatic solvents such as toluene, xylene and n-heptane, aliphatic solvents such as cyclohexane, methylcyclohexane and ethylcyclohexane, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate and acetic acid. Known organic solvents such as ester solvents such as butyl and methyl lactate, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, and alcohol solvents such as methanol, ethanol, isopropyl alcohol and n-propyl alcohol alone Alternatively, several types can be appropriately combined and used.

The coating method of the hard coat paint that forms the hard coat layer is not particularly limited, but gravure coating, micro gravure coating, fountain bar coating, slide die coating, slot die coating, screen printing. After coating by a known coating method such as a spray coating method, it is usually dried at a temperature of about 50 to 120°C.

The coating thickness of the hard coat layer is not particularly limited, but is preferably in the range of, for example, 1.0 μm to 5.0 μm, more preferably in the range of 1.5 μm to 3.5 μm. . If the coating thickness is less than 1.0 μm, the necessary scratch resistance and pencil hardness are lowered, which is not preferable. On the other hand, if the coating thickness exceeds 5.0 μm, the curling tends to occur strongly, and the handleability in the manufacturing process is deteriorated, which is not preferable. The coating thickness of the hard coat layer can be measured by actual measurement with a micrometer.

[Method for producing hard coat film]
The present invention also provides a method for producing a hard coat film having the configuration described above.
That is, the present invention provides a method for producing a hard coat film having a hard coat layer containing an ionizing radiation-curable resin on a cycloolefin polymer-based base film via a primer layer, wherein the cycloolefin polymer-based A polyolefin resin is graft-modified on a substrate film with an α,β-unsaturated carboxylic acid or a derivative thereof and a (meth)acrylic acid ester, and when the modified polyolefin resin is 100% by weight, the α , β-unsaturated carboxylic acid or derivative thereof in a graft weight of 0.4 to 7% by weight and a glass transition point in a range of -30°C to -10°C. A paint for a primer layer was applied and dried to form a primer layer, and then a hard coat layer paint containing an ionizing radiation-curable resin was applied on the primer layer and dried to form a hard coat layer. A method for producing a hard coat film, characterized in that ionizing radiation is subsequently applied.

The details of the modified polyolefin resin are as described above. The preparation of the primer layer paint and the hard coat layer paint, the method of applying these paints, the method of drying the coating film, and the like are also as described above. In addition, the irradiation amount of ionizing radiation (UV, EB, etc.) after the formation of the hard coat layer may be any irradiation amount necessary for imparting sufficient hard properties to the hard coat layer. It can be set as appropriate according to, for example.

Further, the above polyolefin resin is preferably a propylene-ethylene copolymer, for example.

Examples of α,β-unsaturated carboxylic acids or derivatives thereof include maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, and aconitic anhydride. It is preferably one or more compounds selected from acid, hymic acid anhydride, and (meth)acrylic acid.

As described in detail above, according to the present invention, a hard coat layer containing an ionizing radiation-curable resin is laminated on at least one side of a cycloolefin polymer base film via a primer layer, and the primer layer is contains a modified polyolefin resin in which the polyolefin resin is graft-modified with an α,β-unsaturated carboxylic acid or a derivative thereof and a (meth)acrylic acid ester, and the modified polyolefin resin is a modified polyolefin resin is 100% by weight, the graft weight of the α,β-unsaturated carboxylic acid or derivative thereof is in the range of 0.4 to 7% by weight, and the glass transition point is −30° C. to −10° C. , it is possible to obtain a hard coat film having excellent adhesion to a hard coat layer when a cycloolefin polymer film is used as a substrate.

EXAMPLES Next, the embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.
"Parts" and "%" described below represent "parts by weight" and "% by weight", respectively, unless otherwise specified.

[Example 1]
<Production of Modified Polyolefin Resin 1>
100% propylene-ethylene copolymer (88% by weight propylene component, 12% by weight ethylene component, weight average molecular weight 60,000, Tm = 65°C) in a four-necked flask equipped with a stirrer, condenser, and dropping funnel. 4.2 parts by weight of maleic anhydride, 2.6 parts by weight of lauryl methacrylate, and di-t-butyl were dissolved in 400 g of toluene by heating and stirring while maintaining the temperature in the system at 110°C. 2 parts by weight of peroxide was added dropwise over 3 hours, and the reaction was further continued for 1 hour. After the reaction, after cooling to room temperature, the reactant was put into a large excess of acetone for purification, and the weight average molecular weight was 50,000, Tm = 65°C, Tg = -27°C, and the graft weight of maleic anhydride was 3. A modified polyolefin resin 1 having a graft weight of .2% by weight and 2.0% by weight of lauryl methacrylate was obtained. The graft weight of maleic anhydride was measured by alkaline titration, and the graft weight of lauryl methacrylate was measured by ¹ H-NMR. Further, the weight average molecular weight (Mw) is a value calculated by measuring by the gel permeation chromatography (GPC) (standard material: polystyrene) described above, and the melting point (Tm) and glass transition point (Tg) are the values described above. It is a value measured by a differential scanning calorimeter (DSC). In the following examples, etc., measurements were made by the same method.

<Preparation of primer layer paint>
The modified polyolefin resin 1 produced as described above was diluted with butyl acetate/toluene = 85/15 (% by weight) until the solid content concentration (paint concentration) reached 5.5% to prepare a primer layer paint. did.

<Preparation of hard coat layer paint>
Urethane acrylate UV-curable resin "ARTRESIN UN-908 (trade name)" (solid content 100%, number of (meth)acryloyloxy groups: 9, weight average molecular weight: 3600, Negami Kogyo Co., Ltd.) 100 parts as a main agent, Omnirad 184 (photoinitiator, manufactured by IGM Resins) 3.5 parts, TINUVIN 292 (hindered amine light stabilizer, manufactured by BASF) 2.5 parts, leveling agent MEGAFACE RS75 (fluorine-based leveling agent, DIC Corporation) is diluted with butyl acetate/n-propyl alcohol = 50/50 (parts by weight) until the solid content concentration in the UV-curing resin paint reaches 35%, and is thoroughly stirred to harden. A coat layer paint was prepared.

<Preparation of hard coat film>
On one side of 40 μm thick Zeonor Film ZF14 (manufactured by Nippon Zeon Co., Ltd.) as a cycloolefin film, the above primer layer paint is applied using a bar coater (#4), and dried in a drying oven at 100 ° C. The inner wind speed was set to 1 m/sec, and the film was dried with hot air for 60 seconds to dry and solidify to form a primer layer having a coating thickness of 0.4 μm, thereby obtaining a primer layer-coated film.

Next, on the primer layer of the primer layer coated film, the above hard coat layer paint is applied using a bar coater (#6) and dried with hot air for 1 minute in a drying oven at 80 ° C. to obtain a coating film. A coating layer having a thickness of 2.5 μm was formed. This was cured at a UV irradiation dose of 180 mJ/cm ² using a UV irradiation device set at a height of 60 mm from the coating surface to form a hard coat layer, thereby producing a hard coat film of this example.

[Example 2]
<Production of Modified Polyolefin Resin 2>
100% propylene-ethylene copolymer (88% by weight propylene component, 12% by weight ethylene component, weight average molecular weight 100,000, Tm = 65°C) in a four-necked flask equipped with a stirrer, condenser, and dropping funnel. 1.0 parts by weight of maleic anhydride, 1.2 parts by weight of octyl methacrylate, and di-t-butyl were dissolved in 400 g of toluene by heating and stirring while maintaining the temperature in the system at 110°C. 1 part by weight of peroxide was added dropwise over 3 hours, and the reaction was further continued for 1 hour. After the reaction, after cooling to room temperature, the reactant was put into a large excess of acetone for purification, and the weight average molecular weight was 70,000, Tm = 65°C, Tg = -27°C, and the graft weight of maleic anhydride was 0. A modified polyolefin resin 2 having a graft weight of 0.8% by weight and 1.0% by weight of octyl methacrylate was obtained.

<Preparation of hard coat film>
A hard coat film (Example 2) was produced in the same manner as in Example 1, except that the resin blended in the primer layer coating of Example 1 was changed to the modified polyolefin resin 2 described above. did.

[Example 3]
<Production of Modified Polyolefin Resin 3>
100% propylene-ethylene copolymer (88% by weight propylene component, 12% by weight ethylene component, weight average molecular weight 100,000, Tm = 65°C) in a four-necked flask equipped with a stirrer, condenser, and dropping funnel. 2.5 parts by weight of maleic anhydride, 1.8 parts by weight of lauryl methacrylate, and di-t-butyl were dissolved in 400 g of toluene by heating and stirring while maintaining the temperature in the system at 110°C. 1 part by weight of peroxide was added dropwise over 3 hours, and the reaction was further continued for 1 hour. After the reaction, after cooling to room temperature, the reactant was put into a large excess of acetone for purification, and the weight average molecular weight was 70,000, Tm = 65°C, Tg = -27°C, and the graft weight of maleic anhydride was 2. A modified polyolefin resin 3 having a lauryl methacrylate graft weight of 1.6% by weight was obtained.

<Preparation of hard coat film>
A hard coat film (Example 3) was produced in the same manner as in Example 1, except that the resin blended in the primer layer coating of Example 1 was changed to the above modified polyolefin resin 3. did.

[Example 4]
<Production of Modified Polyolefin Resin 4>
100% propylene-ethylene copolymer (propylene component 73% by weight, ethylene component 27% by weight, weight average molecular weight 200,000, Tm = 80°C) in a four-necked flask equipped with a stirrer, condenser, and dropping funnel. 4.2 parts by weight of maleic anhydride, 2.6 parts by weight of octyl methacrylate, and di-t-butyl were dissolved in 400 g of toluene by heating and stirring while maintaining the temperature in the system at 110°C. 2 parts by weight of peroxide was added dropwise over 3 hours, and the reaction was further continued for 1 hour. After the reaction, after cooling to room temperature, the reactant was put into a large excess of acetone for purification, and the weight average molecular weight was 90,000, Tm = 80°C, Tg = -29°C, and the graft weight of maleic anhydride was 3. A modified polyolefin resin 4 having a graft weight of 1% by weight and 2.0% by weight of octyl methacrylate was obtained.

<Preparation of hard coat film>
A hard coat film (Example 4) was produced in the same manner as in Example 1, except that the resin blended in the primer layer coating of Example 1 was changed to the above modified polyolefin resin 4. did.

[Example 5]
<Production of Modified Polyolefin Resin 5>
100% propylene-ethylene copolymer (80% by weight propylene component, 20% by weight ethylene component, weight average molecular weight 170,000, Tm = 72°C) in a four-necked flask equipped with a stirrer, condenser, and dropping funnel. 4.2 parts by weight of maleic anhydride, 2.6 parts by weight of octyl methacrylate, and di-t-butyl were dissolved in 400 g of toluene by heating and stirring while maintaining the temperature in the system at 110°C. 2 parts by weight of peroxide was added dropwise over 3 hours, and the reaction was further continued for 1 hour. After the reaction, after cooling to room temperature, the reaction product was put into a large excess of acetone for purification, and the weight average molecular weight was 80,000, Tm = 72°C, Tg = -29°C, and the graft weight of maleic anhydride was 3. A modified polyolefin resin 5 having a graft weight of .2% by weight and 2.1% by weight of octyl methacrylate was obtained.

<Preparation of hard coat film>
A hard coat film (Example 5) was produced in the same manner as in Example 1 except that the resin blended in the primer layer coating of Example 1 was changed to the modified polyolefin resin 5 described above. did.

[Example 6]
<Production of Modified Polyolefin Resin 6>
100% propylene-ethylene copolymer (89% by weight propylene component, 11% by weight ethylene component, weight average molecular weight 300,000, Tm = 60°C) in a four-necked flask equipped with a stirrer, condenser, and dropping funnel. 4.2 parts by weight of maleic anhydride, 2.6 parts by weight of lauryl methacrylate, and di-t-butyl were dissolved in 400 g of toluene by heating and stirring while maintaining the temperature in the system at 110°C. 2 parts by weight of peroxide was added dropwise over 3 hours, and the reaction was further continued for 1 hour. After the reaction, after cooling to room temperature, the reactant was put into a large excess of acetone for purification, and the weight average molecular weight was 140,000, Tm = 60°C, Tg = -25°C, and the graft weight of maleic anhydride was 3. A modified polyolefin resin 6 having a lauryl methacrylate graft weight of 2.0% by weight was obtained.

<Preparation of hard coat film>
A hard coat film (Example 6) was produced in the same manner as in Example 1 except that the resin blended in the primer layer coating of Example 1 was changed to the modified polyolefin resin 6 described above. did.

[Example 7]
<Production of Modified Polyolefin Resin 7>
Propylene-ethylene-1-butene copolymer (57% by weight propylene component, 31% by weight ethylene component, 12% by weight 1-butene component, weight (average molecular weight: 220,000, Tm = 85°C)) is heated and dissolved in 400 g of toluene, and then 8.0 parts by weight of maleic anhydride and octyl are added while maintaining the temperature in the system at 110°C and stirring. 8.0 parts by weight of methacrylate and 4.5 parts by weight of di-t-butyl peroxide were added dropwise over 3 hours, and the reaction was continued for 1 hour. After the reaction, after cooling to room temperature, the reaction product was put into a large excess of acetone for purification, and the weight average molecular weight was 100,000, Tm = 85°C, Tg = -28°C, and the graft weight of maleic anhydride was 6. A modified polyolefin resin 7 having a graft weight of .2% by weight and 6.5% by weight of octyl methacrylate was obtained.

<Preparation of hard coat film>
A hard coat film (Example 7) was produced in the same manner as in Example 1 except that the resin blended in the primer layer coating of Example 1 was changed to the modified polyolefin resin 7 described above. did.

[Comparative Example 1]
<Production of Modified Polyolefin Resin 8>
100% propylene-ethylene copolymer (88% by weight propylene component, 12% by weight ethylene component, weight average molecular weight 100,000, Tm = 65°C) in a four-necked flask equipped with a stirrer, condenser, and dropping funnel. 10 parts by weight of maleic anhydride, 6.5 parts by weight of lauryl methacrylate, and di-t-butyl peroxide were dissolved in 400 g of toluene by heating and stirring while maintaining the temperature in the system at 110°C. 3.6 parts by weight of each was added dropwise over 3 hours, and the reaction was further performed for 1 hour. After the reaction, after cooling to room temperature, the reactant was put into a large excess of acetone for purification, and the weight average molecular weight was 90,000, Tm = 65°C, Tg = -27°C, and the graft weight of maleic anhydride was 8. A modified polyolefin resin 8 having a lauryl methacrylate graft weight of 4.9% by weight was obtained.

<Preparation of hard coat film>
A hard coat film (Comparative Example 1) was produced in the same manner as in Example 1, except that the resin blended in the primer layer coating of Example 1 was changed to the modified polyolefin resin 8 described above. did.

The hard coat films of Examples and Comparative Examples produced as described above were evaluated for the following items, and the results are summarized in Table 1.

(1) Adhesion Adhesion was evaluated according to JIS-K5600-5-6. Specifically, for each hard coat film, under normal conditions, that is, under constant temperature and humidity conditions (23 ° C., 50% RH), 100 crosscuts of 1 mm ² were prepared using a checkerboard peel test jig, Adhesive tape No. 252 manufactured by Sekisui Chemical Co., Ltd. was pasted thereon, pressed uniformly using a spatula, then peeled off in the direction of 60 degrees, and the number of remaining hard coat layers was evaluated as a residual rate (%). . Adhesion was determined to be acceptable when the hard coat layer remaining rate was 90% or more (90 remaining hard coat layers).

(2) Pencil Hardness Each hard coat film was measured for pencil hardness by a test method according to JIS-K-5600-5-4. Hardness without scratches on the surface was measured. As for the judgment criteria, a hardness of 3B or more was regarded as acceptable.

(3) Scratch resistance For each hard coat film, the surface of the hard coat layer was rubbed back and forth 10 times with steel wool #0000 under a load of 1 kg, according to a test method according to JIS-K-5600-5-10. The degree of damage was evaluated according to the following criteria. ◯ The scratch resistance of the evaluation product was judged to be good. The △ evaluation product can also be used as a product.
○: No scratches
△: Scratches occur a little
×: Numerous scratches occur

As is clear from the results in Table 1 above, when the modified polyolefin resin of the present invention is 100% by weight, the graft weight of the α,β-unsaturated carboxylic acid or derivative thereof is According to the hard coat film of the example using the modified polyolefin resin for the primer layer, which is within the scope of the present invention and whose glass transition point is within the scope of the present invention, the cycloolefin polymer film is used as the base material. A hard coat film having excellent adhesion of the hard coat layer when used can be obtained. Further, according to the examples of the present invention, it is possible to obtain a hard coat film having excellent hard properties (pencil hardness, scratch resistance) of the hard coat layer.

On the other hand, in the hard coat film of the comparative example in which at least one of the graft weight of the α,β-unsaturated carboxylic acid or its derivative and the glass transition point is outside the scope of the present invention, the modified polyolefin resin is used for the primer layer. Adhesion is poor, and poor adhesion of the hard coat layer is likely to occur. The hard coat film of Comparative Example could not be properly evaluated in the above pencil hardness test due to poor adhesion of the hard coat layer.

Claims (5)

A hard coat film in which a hard coat layer containing an ionizing radiation curable resin is laminated on at least one side of a cycloolefin polymer base film via a primer layer,
The primer layer contains a modified polyolefin resin in which the polyolefin resin is graft-modified with an α,β-unsaturated carboxylic acid or a derivative thereof and a (meth)acrylic acid ester,
The polyolefin resin is a propylene-ethylene copolymer in which the ratio (% by weight) of the propylene component and the ethylene component is in the range of propylene component/ethylene component=60/40 to 92/8,
When the modified polyolefin resin is 100% by weight, the graft weight of the α,β-unsaturated carboxylic acid or derivative thereof is in the range of 0.8 to 6.2 % by weight, and the glass transition point is A hard coat film characterized by having a temperature in the range of -29 °C to -25 °C. The α,β-unsaturated carboxylic acid or derivative thereof includes maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, hymic anhydride. 2. The hard coat film according to claim 1, which is one or more compounds selected from acid and (meth)acrylic acid. 3. The hard coat layer according to claim 1, wherein the hard coat layer contains, as the ionizing radiation-curable resin, a polyfunctional acrylate having three or more (meth)acryloyloxy groups in one molecule. coat film. A method for producing a hard coat film having a hard coat layer containing an ionizing radiation curable resin on a cycloolefin polymer base film via a primer layer, comprising:
A polyolefin resin is graft modified with an α,β-unsaturated carboxylic acid or a derivative thereof and a (meth)acrylic acid ester on the cycloolefin polymer base film, and the polyolefin resin is composed of a propylene component and an ethylene component. A propylene-ethylene copolymer having a ratio (% by weight) of propylene component/ethylene component=60/40 to 92/8, and when the modified polyolefin resin is 100 parts by weight, the α, Contains a modified polyolefin resin having a graft weight of β-unsaturated carboxylic acid or derivative thereof in the range of 0.8 to 6.2 % by weight and a glass transition point in the range of -29 °C to -25 °C. Apply the primer layer paint and dry to form a primer layer,
Next, on the primer layer, a hard coat layer coating material containing an ionizing radiation-curable resin is applied, dried to form a hard coat layer, and then subjected to ionizing radiation irradiation to produce a hard coat film. Method. The α,β-unsaturated carboxylic acid or derivative thereof includes maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, hymic anhydride. 5. The method for producing a hard coat film according to claim 4, wherein the compound is one or more compounds selected from acid and (meth)acrylic acid.