JP2022187117A - hard coat film - Google Patents

Abstract

To provide a hard coat film having low moisture permeability, excellent crack resistance and scratch resistance.SOLUTION: There is provided a hard coat film in which a hard coat layer is formed on at least one surface of a substrate film using an ionizing radiation-curable composition containing tricyclodecane dimethanol diacrylate (component A) and a photopolymerization initiator, the ionizing radiation-curable composition further containing a polyester acrylate (component B).SELECTED DRAWING: None

Description

The present invention relates to a hard coat film, and more particularly, flat panel displays such as liquid crystal displays (LCDs), plasma displays, electroluminescence (EL) displays, outdoor display panels, electronic bulletin boards, electronic paper, flexible displays. It relates to a hard coat film in which a hard coat layer is provided on a base film that can be used as a protective film for various displays such as body parts, display device parts such as touch panels, or window glass for buildings, automobiles, trains, etc. .

A display surface of a flat panel 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, it is common practice to provide scratch resistance by using a hard coat film in which a hard coat layer is provided on a base film. In addition, with the spread of touch panels that allow data and instructions to be input by touching the screen with a finger or pen while looking at the display, the functional requirements for a hard coat film that maintains optical visibility and is scratch resistant are increasing. rising. In particular, for flat panels typified by liquid crystal displays, triacetyl cellulose films are used as base films because of their high light transmittance, few defects, lack of polarizing properties, and the like.

By the way, in recent years, liquid crystal display products are becoming lighter and thinner, and each member is being made thinner in response to this. As for the triacetyl cellulose film, which is a constituent member of the polarizing plate, a product with a thickness of 40 μm or less is on the market and is used for mobile products such as smartphones. A hard coat film using such a very thin film as a base film is also required to have substantially the same optical properties and hard properties as conventional ones.

For example, in Patent Document 1, "A thermoplastic resin film such as a triacetyl cellulose film having a thickness of 100 μm or less is used as a support, and on at least one side of the support, ultrafine metal oxide particles having a primary particle diameter of 300 nm or less, Urethane (meth)acrylate (A) containing 3 or more (meth)acryloyl groups in one molecule as an ultraviolet curable resin and having a shrinkage rate of less than 10% after curing, 3 or more in one molecule ( Meta) Consists of polyfunctional acrylate (B) containing an acryloyl group, an organic solvent, and a photopolymerization initiator, and the blending amount of metal oxide ultrafine particles is 5.0 based on the solid content of the coating composition when cured. A hard coat film in which a hard coat layer is formed using a coating composition with a weight % to 20.0% by weight” has been proposed.

JP 2005-288787 A

However, it is known that triacetyl cellulose film has high moisture permeability, and since the moisture permeability increases as the film becomes thinner, the polarizer, which is a constituent member of the polarizing plate, is likely to deteriorate, resulting in changes in optical properties. there is On the other hand, by increasing the thickness of the hard coat layer provided on the base film, the increase in moisture permeability can be suppressed to some extent, but the crack resistance of the hard coat film deteriorates. The crack resistance of the hard coat film is an important factor in the suitability for punch hole processing and curved surface processing, especially in mobile applications, which have been increasing in recent years. That is, it is known that if the hard coat film has poor crack resistance, cracks and chipping of the hard coat layer occur during the above-mentioned processing, causing problems with the appearance of the product. Moreover, there is a problem that the thickening of the hard coat layer results in the thickening of the hard coat film as a whole.
Therefore, at present, there is a demand for a hard coat film capable of suppressing the quality change associated with the thinning of the triacetyl cellulose film as described above.

Therefore, the present invention provides a hard coat film that suppresses an increase in moisture permeability (low moisture permeability) and has crack resistance and scratch resistance even in a hard coat film using a very thin thermoplastic resin film as a base film. An object of the present invention is to provide a coated film.

The inventors of the present invention conducted intensive studies to solve the above problems, and found that the hard coat layer was formed using an ionizing radiation-curable composition containing at least the following component A. The inventors have found that a hard coat film having low moisture permeability and good crack resistance can be obtained without deteriorating scratch resistance, which is quality, and have completed the present invention.

That is, the first invention is a hard coat film in which a hard coat layer is provided on at least one surface of a base film, comprising tricyclodecanedimethanol diacrylate (component A) and a photopolymerization initiator. A hard coat film comprising a hard coat layer formed using an ionizing radiation-curable composition.

A second invention is the hard coat film according to the first invention, wherein the ionizing radiation-curable composition further contains a polyester acrylate (component B).

In a third invention, the compounding ratio of the tricyclodecanedimethanol diacrylate (component A) and the polyester acrylate (component B) in the ionizing radiation-curable composition is component A/component B=95/ The hard coat film according to the second invention, characterized in that the ratio is in the range of 5 to 10/90.

A fourth invention is the hard coat film according to any one of the first to third inventions, wherein the ionizing radiation-curable composition contains a leveling additive.

In a fifth aspect of the invention, the leveling additive is at least one selected from a fluorine-based additive, a siloxane-based additive, an acrylic additive, and an acetylene glycol-based additive. 4. A hard coat film according to the invention of item 4.

A sixth invention is the hard coat film according to any one of the first to fifth inventions, wherein the ionizing radiation-curable composition contains inorganic fine particles or organic fine particles. .

A seventh invention is the hard coat film according to any one of the first to sixth inventions, wherein the hard coat layer has a thickness of 1 μm or more and 10 μm or less.

An eighth invention is the hard coat film according to any one of the first to seventh inventions, wherein the base film is a triacetyl cellulose film having a thickness of 100 μm or less.

According to the present invention, it is possible to provide a hard coat film having good low moisture permeability, crack resistance and scratch resistance. Even if a very thin thermoplastic resin film is used as the base film, it is possible to obtain a hard coat film that suppresses an increase in moisture permeability (low moisture permeability) and has good crack resistance and scratch resistance. That is, according to the present invention, it is possible to obtain a hard coat film that has good scratch resistance, which is the quality required for a transparent protective film, as well as low moisture permeability and good crack resistance.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to its preferred embodiments.
In this specification, "○○ to △△" shall mean "○○ or more and △△ or less" unless otherwise specified.

As in the first invention, the present invention provides a hard coat film in which a hard coat layer is provided on at least one surface of a base film, comprising: tricyclodecane dimethanol diacrylate (component A); A hard coat film comprising a hard coat layer formed using an ionizing radiation-curable composition containing a polymerization initiator.

The ionizing radiation-curable composition used in the present invention contains tricyclodecanedimethanol diacrylate as component A. Component A, tricyclodecanedimethanol diacrylate, can be represented by the following chemical formula.

By forming a hard coat layer using an ionizing radiation-curable composition containing at least tricyclodecanedimethanol diacrylate as component A, the scratch resistance, which is a quality required for a transparent protective film, is not deteriorated. A hard coat film having low moisture permeability and good crack resistance can be obtained.

Regarding the low moisture permeability of the hard coat film, it is considered that the low moisture permeability can be improved by using a hydrophobic component as the component of the hard coat layer provided on the base film. That is, the tricyclodecane structure of tricyclodecane dimethanol diacrylate is considered to be a hydrophobic component, which prevents moisture from entering the hard coat layer, and as a result contributes to the improvement of low moisture permeability. presumed to be.
Furthermore, tricyclodecane dimethanol diacrylate has a large steric hindrance in the tricyclodecane structure, so it is thought that the curing shrinkage of the coating film due to ultraviolet irradiation is small. It is speculated that it also contributes to the improvement of sexuality.

As described above, display products are becoming lighter and thinner in recent years. Therefore, a hard coat film using a thin film as a base film, for example, is required to have substantially the same optical properties and hard properties as conventional ones. For example, triacetyl cellulose film, which has conventionally been preferably used as a base film for hard coat films, has high moisture permeability, and since the moisture permeability is further increased by making it thinner, the hard coat layer provided on the base film is made thicker. By doing so, the increase in moisture permeability can be suppressed to some extent, but the crack resistance of the hard coat film deteriorates.

According to the hard coat film of the present invention, even when a very thin thermoplastic resin film is used as a base film, the increase in moisture permeability is suppressed and low moisture permeability is achieved without increasing the thickness of the hard coat layer. can be realized, and a hard coat film having good crack resistance and scratch resistance can be obtained. That is, according to the present invention, it is possible to obtain a hard coat film having good low moisture permeability, good crack resistance, and good scratch resistance.

Moreover, the ionizing radiation-curable composition used in the present invention can further contain a polyester acrylate as a component B in addition to the component A described above. In other words, it is also a preferred embodiment of the present invention to use both tricyclodecane dimethanol diacrylate (component A) and polyester acrylate (component B) in the ionizing radiation-curable composition.

In the present invention, polyester acrylate represented by the following general formula (I) can be preferably used as the polyester acrylate of component B, for example.

In general formula (I) above, X represents a dihydric alcohol moiety (eg, 1,6-hexanediol) and Y represents a dibasic acid moiety (eg, adipic acid). Here, X may be trivalent or higher, and Y may be a polybasic acid.

As the component B, by using a polyester acrylate having a polyfunctional ionizing radiation reactive group (acrylic group, methacrylic group, etc.) such as a polyester acrylate represented by the general formula (I), excellent scratch resistance is obtained. can be obtained. That is, by having a plurality of ionizing radiation-reactive groups contained in the polyester acrylate, a dense crosslinked structure can be obtained when the coating film is cured by irradiation with ultraviolet rays, thereby improving the scratch resistance. Therefore, by using tricyclodecanedimethanol diacrylate (Component A) and polyester acrylate (Component B) together, the excellent low moisture permeability and crack resistance obtained by tricyclodecanedimethanol diacrylate can be obtained. It is possible to improve the abrasion resistance.

When tricyclodecanedimethanol diacrylate (component A) and polyester acrylate (component B) are used in combination in the ionizing radiation-curable composition as described above, tricyclodecanedimethanol diacrylate (component A) and polyester acrylate ( It is preferable to adjust the compounding ratio of component B) in the range of component A/component B=95/5 to 10/90. Further, it is more preferable to adjust component A/component B in the range of 90/10 to 50/50, and it is further preferable to adjust component A/component B in the range of 90/10 to 60/40.
In addition, in this invention, said compounding ratio represents a mass ratio.

By blending tricyclodecanedimethanol diacrylate (component A) and polyester acrylate (component B) in the above compounding ratio, a hard coat film having good low moisture permeability, crack resistance, and scratch resistance is obtained. be able to. In addition, by adjusting the compounding ratio of tricyclodecane dimethanol diacrylate (component A) and polyester acrylate (component B) within the above range, the quality balance is adjusted for low moisture permeability, crack resistance, and scratch resistance. , and can be optimized.
If component B is blended in a proportion greater than the above blending ratio, low moisture permeability and crack resistance will be insufficient.

As the resin component contained in the ionizing radiation curable composition, in addition to the resins of component A and component B described above, thermoplastic resins such as polyethylene, polypropylene, polystyrene, polycarbonate, polyester, styrene-acrylic, cellulose, etc. Thermosetting resins such as resins, phenolic resins, urea resins, unsaturated polyesters, epoxy resins, silicone resins, etc. may be blended within limits that do not impair the effects of the present invention.

In the present invention, various organic solvents (diluents) can be added to the ionizing radiation-curable composition for the purpose of improving the coatability of the ionizing radiation-curable composition. That is, it can be used to adjust the solution (coating) viscosity when applying the ionizing radiation-curable composition of the present invention. The organic solvent may be any solvent that can uniformly dissolve or disperse at least the solid content (resin, additives (leveling agent, photoinitiator, etc.), etc.). As the solvent that can be used here, there is no particular limitation on the type of organic solvent, but specifically, alcohol solvents such as ethanol and 1-butanol, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, Examples include ester solvents such as ethyl and butyl acetate, aliphatic solvents such as hexane and octane, aromatic solvents such as toluene and xylene, and nitrogen solvents such as nitromethane, propylnitrile, and N,N'-dimethylformamide. do. Cellosolve solvents such as 2-methoxyethanol and 2-ethoxyethanol, and solvents having multiple functional groups such as 2-ethanolamine are also applicable.

The amount of the organic solvent to be blended is preferably 30.0 parts by mass or more, more preferably 50.0 parts by mass or more, relative to 100 parts by mass of the resin component in the ionizing radiation-curable composition. Moreover, it is preferable that it is 500 mass parts or less from a viewpoint of productivity.

In the present invention, the ionizing radiation curable composition contains a photopolymerization initiator. By irradiating this with ultraviolet rays or the like, the resin undergoes a polymerization reaction and is cured. As the photopolymerization initiator, any known initiator such as a benzophenone-based initiator, a diketone-based initiator, an acetophenone-based initiator, a benzoin-based initiator, a thioxanthone-based initiator, a quinone-based initiator, a phenylphosphine oxide-based initiator, etc. A polymerization initiator may be used. Industrially available products include Irgacure 184, 651, 907, 369, 1700 and 819 manufactured by BASF, Darocure 1173 manufactured by Merck, and Kayacure MBP and DMBI manufactured by Nippon Kayaku. Usually, the photopolymerization initiator is used in an amount of 1.0 to 10.0% by mass with respect to a curable resin component such as an ultraviolet curable resin.

In the present invention, in order to obtain coatability of the ionizing radiation-curable composition, a leveling additive that acts on the surface of the coating film after coating to lower the surface tension can be added. The leveling additive is preferably at least one selected from fluorine additives, siloxane additives, acrylic additives, and acetylene glycol additives. Although not particularly limited, for example, Sumitomo 3M Florard FC-430 and FC170 as fluorine-based additives, Dainippon Ink and Chemicals Co. Megafac F177 and F471, BYK-300 and BYK- manufactured by BYK-Chemie as siloxane additives 077, acrylic additives such as BYK-380 manufactured by BYK Chemie, Disparon L-1984-50 and 1970 manufactured by Kusumoto Kasei Co., Ltd., and acetylene glycol additives such as Dynol 604 and Surfynol 104 manufactured by Shin-Etsu Chemical Co., Ltd. These leveling additives can be used alone or in combination.

The amount of the leveling additive used in the present invention is preferably 0.05% by mass or more and 10.0% by mass or less, more preferably 0.05% by mass or more and 10.0% by mass or less, based on the solid content of the ionizing radiation-curable composition when cured. It is 2 mass % or more and 5.0 mass % or less. If the amount is less than 0.05% by mass, the leveling properties of the additive may not be exhibited. In addition, the above additives do not have reactive functional groups (thermosetting functional groups such as epoxyl groups, vinyl groups, and alkoxyl groups, or ionizing radiation-curable functional groups such as acrylic groups and methacrylic groups). Therefore, when the blending amount exceeds 10.0% by mass, the hardness of the obtained hard coat film is remarkably lowered.

In the present invention, in order to obtain coatability of the ionizing radiation-curable composition, the solid content concentration of the composition is preferably 15.0% by mass or more and 65.0% by mass or less. When the solid content concentration is lower than 15.0% by mass, the viscosity of the composition tends to decrease, resulting in significant dry unevenness on the coated surface. On the other hand, when the solid content concentration is higher than 65.0% by mass, the viscosity of the composition tends to be high and uniformity of the coated surface cannot be obtained.

Furthermore, in order to improve the performance, the ionizing radiation-curable composition may contain antifoaming agents, thixotropic agents, antioxidants, ultraviolet absorbers, light stabilizers, and polymerization inhibitors within a range that does not affect the effects of the present invention. etc. can be contained.
In addition, in order to impart antiglare properties by making the surface of the hard coat layer uneven, a crosslinked or uncrosslinked resin polymer such as polyurethane, polystyrene, melamine resin, or PMMA may be used within a range that does not affect the effects of the present invention. Organic fine particles and inorganic fine particles such as silica, alumina, titania, calcium oxide, zirconium oxide and zinc oxide can also be added.

The hard coat film of the present invention preferably uses a thermoplastic resin film as the base film. The substrate film used in the present invention is preferably in the form of a transparent sheet or film. Examples include polyester film, polyethylene film, polypropylene film, cellophane film, diacetylcellulose film, triacetylcellulose film, acetylcellulose butyrate film, Polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, polystyrene film, polycarbonate film, polymethylpentel film, polysulfone film, polyetherketone film, polyethersulfone film, polyetherimide film, polyimide Thermoplastic resin films such as films, fluororesin films, nylon films, and acrylic films can be used. In the present invention, it is particularly preferable to use a triacetyl cellulose film (TAC film), which is widely used as a member of polarizing plates in liquid crystal displays because of its lack of optical anisotropy. However, since TAC film is usually formed by a solution casting method, it has poor flatness and high transparency, so it is very difficult to form a uniform hard coat layer without defects caused by aggregation, etc. is. The present invention is particularly effective when forming a uniform hard coat layer on such a highly transparent substrate film.
Moreover, the present invention is particularly effective when a thin thermoplastic resin film, such as a triacetyl cellulose film having a thickness of 100 μm or less, preferably 50 μm or less, is used as the base film.

The production of the hard coat film of the present invention requires at least a step of applying the ionizing radiation-curable composition to the substrate film, a step of drying the coating film, and a step of curing the coating film using ultraviolet rays or the like. That is, the ionizing radiation-curable composition (hard coat paint) of the present invention, the solution viscosity of which was appropriately adjusted with the aforementioned diluent (organic solvent), was applied onto a substrate film and dried to form a coating film. After that, the coating film is irradiated with ionizing radiation to form a cured coating film (hard coat layer) of the ionizing radiation-curable composition, thereby completing the hard coat film of the present invention.

As described above, the hard coat layer of the present invention is formed by coating the ionizing radiation-curable composition on a substrate film using a known coating apparatus, drying the composition, and then curing the composition by irradiating it with ultraviolet rays or the like. formed by As known coating devices, known coating devices such as micro gravure coaters, gravure coaters, Meyer bar coaters, die coaters, screen printing methods and spray coating methods can be used. The viscosity and concentration of the ionizing radiation-curable composition during coating can be adjusted to appropriate values depending on the coating apparatus used.

In the process of drying the coating film after the application of the ionizing radiation curable composition, the temperature of the base material (the temperature of the base film or coating film) usually rises, depending on the type of diluent (organic solvent) described above. It is preferable to dry the coating film under conditions of 50°C to 150°C.

In addition, the irradiation light amount of ionizing radiation (UV, EB, etc.) to the coating film after drying may be any irradiation light amount necessary to give the hard coat layer sufficient hard properties. It can be set as appropriate according to, for example. In the present invention, the integrated amount of irradiated light is preferably 50 to 450 mJ/cm ² , more preferably 100 to 400 mJ/cm ² . If the integrated amount of light is less than 50 mJ/cm ² , the polymerization reaction of the curable resin component contained in the ionizing radiation-curable composition is not promoted, and the hard coat film cannot have sufficient hardness. On the other hand, when the integrated amount of light exceeds 450 mJ/cm ² , while the polymerization reaction of the curable resin component proceeds sufficiently, the thermoplastic resin film, which is the base film, is deformed due to the influence of heat. The integrated amount of light in the present invention refers to a value measured by "UV POWER PUCKTM" manufactured by Fusion UV Systems.

In the present invention, the thickness of the hard coat layer after curing is generally 1 μm to 10 μm, preferably 1.5 μm to 8 μm. If the film thickness exceeds 10 μm, the low moisture permeability is improved, but the crack resistance is lowered and the hard coat film tends to curl. On the other hand, when the film thickness is less than 1 μm, the low moisture permeability becomes insufficient.

As described in detail above, according to the present invention, even if a hard coat film having a very thin thermoplastic resin film as a base film, the increase in moisture permeability is suppressed (low moisture permeability) and resistance is improved. A hard coat film having good crack resistance and scratch resistance can be provided. That is, it is possible to obtain a hard coat film that has good scratch resistance, which is the quality required for a transparent protective film, low moisture permeability, and good crack resistance.

The hard coat film of the present invention can be used for various displays such as flat panel displays such as liquid crystal displays (LCD), plasma displays, and electroluminescence (EL) displays, outdoor display panels, electronic bulletin boards, electronic paper, and flexible displays. , display device parts such as touch panels, or as protective films for windows of buildings, automobiles, trains, and the like.

EXAMPLES The present invention will be described in detail below with reference to examples. The following examples are intended to better illustrate the invention and are not intended to limit the invention. In the descriptions below, "parts" means parts by mass unless otherwise stated, and "%" means % by mass unless otherwise stated.

(Example 1)
[Preparation of ionizing radiation curable composition]
100 parts of tricyclodecane dimethanol diacrylate (Component A) "IRR-214K" (manufactured by Daicel Allnex), 5 parts of photopolymerization initiator "Irgacure 184" (manufactured by BASF), hindered amine light stabilizer 3.3 parts of "Tinuvin 292" (manufactured by BASF), 0.7 parts of siloxane additive "BYK-313" (manufactured by BYK-Chemie), fluorine additive "FT-681" (manufactured by Neos) 3 7 parts were mixed, and a mixed solution of ethyl acetate/ethyl cellosolve=60%/40% was added as a solvent and thoroughly stirred to prepare an ionizing radiation curable composition (1) having a solid content of 30%.
[Preparation of hard coat film]
The ionizing radiation-curable composition (1) prepared as described above was cast on a 25 μm-thick triacetyl cellulose film (trade name: TJ25UL, manufactured by Fuji Film Co., Ltd.) as a base film, and was uniformly spread using a wire bar. applied. Next, this coating film is dried with hot air in a drying oven at 80° C. for 1 minute, and then irradiated with ultraviolet rays at an irradiation light amount of 100 mJ/cm ² using an ultraviolet irradiation device to cure the coating film. A hard coat film of Example 1 was produced by forming a hard coat layer of 3.9 μm.

(Example 2)
The amount of tricyclodecanedimethanol diacrylate (component A) "IRR-214K" in Example 1 was changed from 100 parts to 75 parts, and polyester acrylate (component B) "M-7300K" (manufactured by Toagosei Co., Ltd.) was added to 25 parts. An ionizing radiation-curable composition (2) was prepared in the same manner as in Example 1, except that
Using this ionizing radiation-curable composition (2), a hard coat layer having a thickness of 4 μm was formed on the base film in the same manner as in Example 1 to prepare a hard coat film of Example 2.

(Example 3)
Except that the amount of tricyclodecanedimethanol diacrylate (component A) "IRR-214K" in Example 1 was changed from 100 parts to 50 parts, and 50 parts of polyester acrylate (component B) "M-7300K" was added. An ionizing radiation-curable composition (3) was prepared in the same manner as in Example 1.
Using this ionizing radiation-curable composition (3), a hard coat layer having a thickness of 4 μm was formed on the base film in the same manner as in Example 1 to prepare a hard coat film of Example 3.

(Example 4)
Except that the amount of tricyclodecanedimethanol diacrylate (component A) "IRR-214K" in Example 1 was changed from 100 parts to 25 parts, and 75 parts of polyester acrylate (component B) "M-7300K" was added. An ionizing radiation-curable composition (4) was prepared in the same manner as in Example 1.
Using this ionizing radiation-curable composition (4), a hard coat layer having a thickness of 4 μm was formed on the base film in the same manner as in Example 1 to prepare a hard coat film of Example 4.

(Example 5)
Example 5 was prepared in the same manner as in Example 1, except that the ionizing radiation-curable composition (1) of Example 1 was used to form a hard coat layer having a thickness of 1.7 μm on the base film. A hard coat film was produced.

(Example 6)
Example 6 was prepared in the same manner as in Example 1, except that the ionizing radiation-curable composition (2) of Example 2 was used to form a hard coat layer having a thickness of 1.8 μm on the base film. A hard coat film was produced.

(Example 7)
Example 7 was prepared in the same manner as in Example 1, except that the ionizing radiation-curable composition (3) of Example 3 was used to form a hard coat layer having a thickness of 1.7 μm on the base film. A hard coat film was produced.

(Comparative example 1)
Example 1 except that the amount of tricyclodecanedimethanol diacrylate "IRR-214K" in Example 1 was 0 parts and the amount of polyester acrylate (component B) "M-7300K" was 100 parts. An ionizing radiation curable composition (5) was prepared in the same manner.
Using this ionizing radiation-curable composition (5), a hard coat layer having a thickness of 3.9 μm was formed on the base film in the same manner as in Example 1, to prepare a hard coat film of Comparative Example 1. did.

(Comparative example 2)
In the same manner as in Example 1 except that 100 parts of urethane acrylate "UN-904" (manufactured by Negami Kogyo Co., Ltd.) was used instead of tricyclodecanedimethanol diacrylate "IRR-214K" in Example 1, ionization was performed. A radiation curable composition (6) was prepared.
Using this ionizing radiation-curable composition (6), a hard coat layer having a thickness of 3.9 μm was formed on the base film in the same manner as in Example 1 to prepare a hard coat film of Comparative Example 2. did.

(Comparative Example 3)
In the same manner as in Example 1 except that 100 parts of pentaerythritol triacrylate "PE3A" (manufactured by Kyoeisha Chemical Co., Ltd.) was used instead of tricyclodecanedimethanol diacrylate "IRR-214K" in Example 1, ionization was performed. A radiation curable composition (7) was prepared.
Using this ionizing radiation-curable composition (7), a hard coat layer having a thickness of 3.9 μm was formed on the base film in the same manner as in Example 1 to prepare a hard coat film of Comparative Example 3. did.

(Comparative Example 4)
Same as Example 1 except that 100 parts of dipentaerythritol hexaacrylate "A-9550" (manufactured by Shin-Nakamura Chemical Co., Ltd.) was used instead of tricyclodecanedimethanol diacrylate "IRR-214K" in Example 1. to prepare an ionizing radiation curable composition (8).
Using this ionizing radiation-curable composition (8), a hard coat layer having a thickness of 3.8 μm was formed on the base film in the same manner as in Example 1 to prepare a hard coat film of Comparative Example 4. did.

[Preparation of hard coat film (for evaluation of crack resistance)]
(Examples 1 to 7, Comparative Examples 1 to 4)
An 80 μm-thick triacetyl cellulose film (manufactured by Fuji Film Co., Ltd., brand: TD80ULP) was used as the base film, and the film thickness of the hard coat layer was adjusted to be in the range of 6.7 μm to 7.2 μm (see Table 1 below). The hard coat films for evaluation of crack resistance (Examples 1 to 7, Comparative Examples 1 to 4) were prepared in the same manner as in the preparation of the hard coat films of the above Examples and Comparative Examples, except that made.

The compositions of the ionizing radiation-curable compositions in the above Examples and Comparative Examples are also shown in Table 1 below. In each column of composition in the table, the upper column indicates the substance name (above brand name), and the lower column indicates the compounding amount (parts).

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

[Evaluation of moisture permeability]
Moisture permeability was evaluated based on the test method described in JIS Z-0208. Each hard coat film produced in Examples and Comparative Examples was cut into a circular shape with a diameter of 70 mm, and evaluated after 24 hours in an environment of a temperature of 40° C. and a relative humidity of 90%. A smaller value indicates a lower moisture permeability.

[Evaluation of crack resistance]
Crack resistance was evaluated by a mandrel test. Each hard coat film prepared in Examples and Comparative Examples was wound around a mandrel with a diameter of 1.2 to 8 mm, the occurrence of cracks was visually confirmed, and the minimum mandrel diameter (mm unit) at which cracks did not occur was evaluated. . A smaller number indicates better crack resistance, and a larger number indicates poorer crack resistance and brittleness. However, when evaluating a hard coat film with a thickness of 1.5 to 8 μm (1.7 to 4 μm in the above example) using a triacetyl cellulose film with a thickness of 25 μm as the base film, the actual When processed as a product, cracks occur and the appearance of the product is abnormal. It is possible that the gender cannot be evaluated. Therefore, for crack resistance, as described above, a triacetyl cellulose film with a thickness of 80 μm was used as the base film, and the thickness of the hard coat layer was set to be in the range of 6.7 μm to 7.2 μm (thick film). (Severe conditions) A hard coat film for evaluating crack resistance was also evaluated in the same manner.

[Evaluation of scratch resistance]
Scratch resistance was evaluated by a friction test with steel wool. For each of the hard coat films prepared in Examples and Comparative Examples, the surface of the hard coat layer was rubbed back and forth with #0000 steel wool under a load of 3.92 N, and the degree of damage was evaluated according to the following criteria.
Evaluation Criteria ⊚: 0 to 1 scratch occurs. ◯: 2 to 10 scratches are generated. Δ: 11 to 20 scratches are generated. x: 20 or more scratches are generated.

[Evaluation of Curl]
After cutting each hard coat film prepared in Examples and Comparative Examples into A4 size (210 mm×297 mm), the coated surface of the hard coat layer was turned up and the average height of the four corners was evaluated. When the sample is cylindrical, the diameter of the cylinder is indicated by φ.

As is clear from the results in Table 1 above, according to the hard coat films of the examples of the present invention, hard coat films having good low moisture permeability, crack resistance, and scratch resistance can be provided. Even if a very thin thermoplastic resin film is used as the base film, it is possible to obtain a hard coat film that suppresses an increase in moisture permeability (low moisture permeability) and has good crack resistance and scratch resistance. That is, according to the present invention, it is possible to obtain a hard coat film having good scratch resistance, which is the quality required for a transparent protective film, low moisture permeability, and good crack resistance. Further, when tricyclodecanedimethanol diacrylate (component A) and polyester acrylate (component B) are used in combination in the ionizing radiation curable composition (Examples 2 to 4, 6 to 7), tricyclodecanedimethanol diacrylate By adjusting the blending ratio of acrylate (component A) and polyester acrylate (component B) in the range of component A / component B = 95/5 to 10/90, low moisture permeability, crack resistance and scratch resistance Quality balance can be adjusted and optimized.

On the other hand, Comparative Example 1 in which the ionizing radiation-curable composition for forming the hard coat layer does not contain at least the tricyclodecanedimethanol diacrylate (component A) of the present invention (other acrylate-based components are contained instead). A hard coat film having low moisture permeability, good crack resistance, and good scratch resistance cannot be obtained with hard coat films of No. 4 to No. 4, and practical improvements are desired.

Claims (8)

A hard coat film having a hard coat layer provided on at least one surface of a base film, using an ionizing radiation curable composition containing tricyclodecanedimethanol diacrylate (component A) and a photopolymerization initiator. A hard coat film, wherein a hard coat layer is formed by 2. A hard coat film according to claim 1, wherein said ionizing radiation curable composition further comprises a polyester acrylate (component B). The compounding ratio of the tricyclodecanedimethanol diacrylate (component A) and the polyester acrylate (component B) in the ionizing radiation-curable composition is in the range of component A/component B = 95/5 to 10/90. The hard coat film according to claim 2, characterized in that there is 4. The hard coat film according to any one of claims 1 to 3, wherein the ionizing radiation-curable composition contains a leveling additive. 5. The hard coat film according to claim 4, wherein the leveling additive is at least one selected from fluorine additives, siloxane additives, acrylic additives and acetylene glycol additives. . 6. The hard coat film according to any one of claims 1 to 5, wherein the ionizing radiation-curable composition contains inorganic fine particles or organic fine particles. 7. The hard coat film according to any one of claims 1 to 6, wherein the hard coat layer has a thickness of 1 µm or more and 10 µm or less. 8. The hard coat film according to any one of claims 1 to 7, wherein the base film is a triacetyl cellulose film having a thickness of 100 µm or less.