JP2008231163A - Composition for forming hardcoat layer, and hardcoat film obtained using the same and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a composition for forming hardcoat layers that can impart excellent scratch resistance and high hardness to the layers without deteriorating adhesion to a substrate and curling resistance, a hardcoat film obtained using the same and its manufacturing method. <P>SOLUTION: The composition for forming hardcoat layers comprises a polyfunctional (meth)acrylic monomer (A), a hydroxy group-bearing (meth)acrylic monomer (B), a photoradical polymerization initiator (C) and a blocked isocyanate compound (D) capable of forming an isocyanate group by a heat treatment. The hardcoat film 1 comprises a laminate 10 comprising a transparent substrate 12 and, laminated thereon, a hardcoat layer 11 obtained by hardening the composition, where the film thickness of the hardcoat layer 11 is 5-25 μm. The manufacturing method of the hardcoat film is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a hard coat used for the purpose of protecting the surface of a display such as a cathode ray tube display (CRT), a liquid crystal display (LCD), a plasma display panel (PDP), or a field emission display (FED). The present invention relates to a layer forming composition, a hard coat film using the composition, and a method for producing the same.

  A resin layer is usually formed on a protective film for a polarizing plate for a liquid crystal display or a protective film for a circularly polarizing plate used for an organic EL display or the like in order to give various functions. Examples of the resin layer include an antistatic layer for imparting an antistatic function, an antireflection layer for suppressing reflection, and a hard coat layer for improving surface hardness. In recent years, in particular, a hard coat layer has been indispensable for display applications, and the hard coat layer is used not only as a single layer but also as a lower layer of an antireflection layer. Thus, forming a hard coat layer is an important technique.

As a material using a hard coat layer, for example, Patent Document 1 discloses a silicone whose adhesion in a cross-cut peel test is 50 or more in 100 on the surface of a base material formed of a thermoplastic norbornene resin. A molded product made of a thermoplastic norbornene resin having a hard coat layer is disclosed.
Patent Document 2 is formed from a coating film component containing one or more organic components having a polymerizable functional group and an inorganic filler, and at least one of the organic components does not have a hydrogen bond-forming group. There is disclosed a hard coat film for a plastic substrate film, which is characterized by the above.
Furthermore, Patent Document 3 discloses a hard coat film having a hard coat layer that is a cured coating film layer on at least one surface of a transparent plastic film substrate, and the hard coat layer forming material includes urethane acrylate, isocyanuric acid acrylate, and A hard coat film containing inorganic ultrafine particles is disclosed.

In recent years, the hard coat film provided with the hard coat layer having a function of protecting the polarizing plate is required to have high hardness.
However, since the base material used for the hard coat film is mainly a soft cellulose ester film, it has been very difficult to increase the hardness of the hard coat film.

  One of the means for obtaining a hard coat film with high hardness is a method for increasing the hardness of the hard coat layer. When the hardness of the hard coat layer is insufficient, the thickness of the hard coat layer may be increased in order to satisfy the required hardness. However, since many of the compositions forming the hard coat layer (hard coat layer forming compositions) are polymerizable compositions, increasing the film thickness hardens the hard coat layer forming composition and hard coat layers. When forming the film, volume shrinkage occurred, and the hard coat layer and the base material were sometimes deformed (curled).

Therefore, in order to suppress deformation of the hard coat layer and the base material, a method (method 1) of adding a filler such as a filler or a polymer to the hard coat layer forming composition has been proposed.
Further, a method (Method 2) for improving the adhesion between the hard coat layer and the substrate by dissolving the substrate in a solvent contained in the composition for forming a hard coat layer has been proposed. According to Method 2, since the adhesion between the hard coat layer and the substrate is improved, the hard coat layer and the substrate are hardly deformed even when the hard coat layer forming composition is cured.
Japanese Unexamined Patent Publication No. 7-97468 JP 2000-159916 A JP 2006-106427 A

However, Method 1 has problems such as dispersibility of the filler and polymer, reduction in pencil hardness due to addition of the polymer, and increase in production cost.
Moreover, when the base material is dissolved as in Method 2, the hardness of the hard coat layer may be reduced.
Since the hard coat film is often provided on the surface of the image display device, it is desired that the hard coat film be excellent in scratch resistance.

  The present invention takes the above circumstances into consideration, and a composition for forming a hard coat layer capable of imparting excellent scratch resistance and high hardness without deteriorating adhesion and curl resistance with a substrate, and It aims at realization of the used hard coat film and its manufacturing method.

  As a result of intensive studies, the present inventors have focused on a blocked isocyanate compound that generates an isocyanate group by heat treatment. And in manufacture of a hard coat film, after hardening the composition for hard-coat layer formation and forming a hard-coat layer, by heating a base material provided with a hard-coat layer, not only by a curing reaction but by heating It has been found that the hardness of the hard coat layer is increased due to the progress of the thermal crosslinking reaction, and as a result, the hardness of the hard cord film is improved, and the present invention has been completed.

  That is, the composition for forming a hard coat layer of the present invention comprises a polyfunctional (meth) acrylic monomer (A), a (meth) acrylic monomer (B) having a hydroxyl group, a radical photopolymerization initiator (C), and heating. It contains the blocked isocyanate compound (D) which produces | generates an isocyanate group by a process.

  Here, the polyfunctional (meth) acrylic monomer (A) preferably contains a urethane (meth) acrylate monomer and / or an oligomer as a main component.

Moreover, it is preferable that content of the said polyfunctional (meth) acryl monomer (A) is 35-90 mass% in solid content of 100 mass% of the said composition for hard-coat layer formation.
Furthermore, it is preferable that content of the (meth) acryl monomer (B) having the hydroxyl group is 10 to 50% by mass in 100% by mass of the solid content of the composition for forming a hard coat layer.
Moreover, it is preferable that content of the said block isocyanate compound (D) is 5-50 mass% in solid content of 100 mass% of the said composition for hard-coat layer formation.
Furthermore, it is preferable that content of the said radical photopolymerization initiator (C) is 0.01-10 mass% in solid content of 100 mass% of the said composition for hard-coat layer formation.

The hard coat film of the present invention has a laminate in which a hard coat layer obtained by curing the composition for forming a hard coat layer is laminated on a transparent substrate, and the film thickness of the hard coat layer is It is 5 to 25 μm.
Furthermore, the transparent substrate is preferably cellulose triacetate.

Further, the method for producing a hard coat film of the present invention includes a coating step in which a paint obtained by dissolving the hard coat layer forming composition in a solvent is applied onto a transparent substrate, and a paint applied on the transparent substrate. A drying step of drying the coating, a curing step of irradiating the coating with ionizing radiation to form a hard coat layer, and a heating step of heating a transparent substrate provided with the hard coat layer.
Furthermore, it is preferable to perform the said heating process at 40-150 degreeC for 1 minute-120 hours.

According to the composition for forming a hard coat layer of the present invention, excellent scratch resistance and high hardness can be imparted without deteriorating the adhesion to the substrate and the curl resistance.
Moreover, according to the method for producing a hard coat film of the present invention, a hard coat film having excellent scratch resistance and high hardness can be obtained.
The hard coat film of the present invention has excellent scratch resistance and high hardness.

Hereinafter, the present invention will be described in detail.
[Composition for forming hard coat layer]
The composition for forming a hard coat layer of the present invention comprises a polyfunctional (meth) acrylic monomer (A), a (meth) acrylic monomer (B) having a hydroxyl group, a radical photopolymerization initiator (C), and a blocked isocyanate compound. (D).

  As the polyfunctional (meth) acrylic monomer (A) (hereinafter sometimes referred to as “component (A)”), a polyhydric alcohol having two or more alcoholic hydroxyl groups in one molecule and two or more Examples include an esterified product with (meth) acrylic acid, a compound in which a reactive acrylic group is bonded to an acrylic resin skeleton, and a compound in which an acrylic group is bonded to a rigid skeleton such as melamine or isocyanuric acid. Specific examples include monomers such as polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, and polyether (meth) acrylate, or oligomers thereof. Among these, it is preferable to use a urethane (meth) acrylate monomer and / or oligomer as a main component because the hardness and flexibility of the hard coat layer can be remarkably improved. In particular, urethane acrylate monomers and / or oligomers are preferred.

Examples of the urethane acrylate include those that can be easily formed by reacting an acrylate monomer having a hydroxyl group with a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer.
Specific examples include pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate toluene diisocyanate urethane prepolymer. Pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer, and the like can be used. These may be used alone or in combination of two or more. Further, it may be in the form of a monomer when formed into a paint, or may be an oligomer partially polymerized.

  In the present invention, a commercially available polyfunctional acrylic monomer may be used as the component (A). For example, Dainippon Ink Chemical Co., Ltd., such as “Diabeam” series manufactured by Mitsubishi Rayon Co., Ltd., “Denacol” series manufactured by Nagase ChemteX Co., Ltd., “NK Ester” series manufactured by Shin-Nakamura Chemical Co., Ltd., etc. "KAYARAD" series manufactured by Nippon Kayaku Co., Ltd., such as "Unidic" series manufactured by Kogyo Co., Ltd., "Aronix" series manufactured by Toa Gosei Co., Ltd., "Blemmer" series manufactured by Nippon Oil & Fats Co., Ltd. And other products such as “Light Ester” series and “Light Acrylate” series manufactured by Kyoeisha Chemical Co., Ltd. and “Shikou” series manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

(A) As for content of a component, 35-90 mass% is preferable in solid content of 100 mass% of the composition for hard-coat layer formation, and 50-90 mass% is more preferable. When the content is less than 35% by mass, it becomes difficult to obtain a hard coat layer having sufficient hardness. On the other hand, if the content exceeds 90% by mass, the component (A) may be cured and contracted during curing, and the hard coat film may be largely curled on the cured coating side.

  As the (meth) acrylic monomer (B) having a hydroxyl group (hereinafter sometimes referred to as “component (B)”), it is preferable to use polyfunctional (meth) acrylate from the viewpoint of increasing the hardness of the hard coat film. . Specific examples include hydroxyethyl acrylate, hydroxyethyl methacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and the like. Of these, dipentaerythritol pentaacrylate is preferred. Moreover, you may use a commercially available (meth) acryl monomer. These may be used alone or in combination of two or more.

  (B) 10-50 mass% is preferable in solid content of 100 mass% of the composition for hard-coat layer formation, and, as for content of a component, 10-30 mass% is more preferable. When the content is less than 10% by mass, a thermal crosslinking reaction hardly occurs during the heating step described later, and a hard coat layer having sufficient hardness is hardly obtained. On the other hand, when the content exceeds 50% by mass, the ratio of the component (A) in the entire composition for forming a hard coat layer is decreased, so that the pencil hardness may be decreased.

  The radical photopolymerization initiator (C) (hereinafter sometimes referred to as “component (C)”) generates radicals by irradiating with ionizing radiation, and polymerization reaction of component (A) or component (B). Compounds starting with are preferred. Specifically, acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, 4,4′-dichlorobenzophenone, 4,4′-bisdiethylamino Benzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxy Carbonyl compounds such as cyclohexyl phenyl ketone; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, thioxanthone, 2-chlorothio And sulfur compounds such as xanthone and 2-methylthioxanthone. These may be used alone or in combination of two or more.

  (C) 0.01-10 mass% is preferable in solid content of 100 mass% of the composition for hard-coat layer formation, and, as for content of a component, 0.1-10 mass% is more preferable. When the content is less than 0.01% by mass, a sufficient curing reaction is difficult to proceed when irradiated with ionizing radiation. On the other hand, if the content exceeds 10% by mass, the polymerization reaction may start before the ionizing radiation reaches the entire hard coat layer forming composition.

The blocked isocyanate compound (D) (hereinafter sometimes referred to as “component (D)”) is stable without reacting even in the presence of active hydrogen in a normal state (protected state), but it is not until heated. This is a compound having a property that an active isocyanate group is generated by elimination of a blocking group protecting an isocyanate group. This active isocyanate group reacts rapidly with a group having active hydrogen, preferably a hydroxyl group, to form a urethane bond. Therefore, in the present invention, the deblocking of the component (D) proceeds in the heating step described later to generate an active isocyanate group, and the isocyanate group reacts with the hydroxyl group of the component (B) to form a urethane bond. . This means that the thermal crosslinking reaction proceeds in the hard coat layer, and as a result, the pencil hardness of the hard coat film is improved in the heating step.
In addition, (D) component differs from a general isocyanate compound, and reaction does not advance easily at the temperature of about room temperature. Therefore, it has the advantage that it is excellent in storage stability by using (D) component.

The component (D) is preferably a compound in which the blocked isocyanate compound has a (meth) acrylate group. This makes it possible to copolymerize with the component (A), and it is possible to further increase the hardness by radical polymerization by ionizing radiation and a thermal crosslinking reaction by a heating step.
As such component (D), commercially available products can be used, and examples thereof include “Karenz MOI-BP” and “Karenz MOI-BM” manufactured by Showa Denko KK.

  (D) 5-100 mass% is preferable in solid content of 100 mass% of the composition for hard-coat layer formation, and, as for content of a component, 10-30 mass% is more preferable. When the content is less than 5% by mass, a sufficient thermal crosslinking reaction does not proceed easily. On the other hand, when the content exceeds 50% by mass, the ratio of the component (A) in the entire composition for forming a hard coat layer is decreased, so that the pencil hardness may be decreased.

In addition to the components described above, the hard coat composition of the present invention includes a modifier for improving the properties of the hard coat layer and a hard coat film as long as the reaction by ionizing radiation is not impaired. A thermal polymerization inhibitor for preventing thermal polymerization at the time or dark reaction during storage of the composition for forming a hard coat layer may be contained.
As modifiers, coatability improvers, antifoaming agents, thickeners, antistatic agents, inorganic particles, organic particles, organic lubricants, organic polymer compounds, ultraviolet absorbers, light stabilizers, dyes , Pigments, stabilizers and the like.
The content of these modifiers is preferably 0.01 to 5% by mass in 100% by mass of the solid content of the composition for forming a hard coat layer.

Examples of the thermal polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, and 2,5-t-butyl hydroquinone.
The content of the thermal polymerization inhibitor is preferably 0.005 to 0.05% by mass in 100% by mass of the solid content of the composition for forming a hard coat layer.

[Hard coat film]
FIG. 1 is a cross-sectional view showing one embodiment of the hard coat film of the present invention. The hard coat film 1 of the present invention has a laminate 10 in which a hard coat layer 11 obtained by curing the above-described composition for forming a hard coat layer is laminated on a transparent substrate 12.
The transparent substrate 12 preferably has translucency, and examples thereof include plastics such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, polyacrylate, and cellulose acetate. Moreover, plate-shaped things, such as a sheet | seat and a film, are preferable. Among these, from the viewpoint of optical properties such as high transparency and low birefringence, a film of cellulose acetate, particularly cellulose triacetate is preferable.

10-200 micrometers is preferable and, as for the film thickness of the transparent base material 12, 20-150 micrometers is more preferable. When the film thickness is less than 10 μm, the physical strength as a film substrate is insufficient. On the other hand, when the film thickness is greater than 200 μm, handling as a film substrate becomes difficult.
The film thickness of the hard coat layer 11 is determined by the required hardness, but is preferably 5 to 25 μm, more preferably 5 to 20 μm. When the film thickness is less than 5 μm, it becomes difficult to obtain sufficient hardness. On the other hand, when the film thickness is greater than 25 μm, the base material is likely to curl due to curing shrinkage of the hard coat layer, and defects such as fracture are likely to occur in the next step.

<Manufacturing method>
Here, the manufacturing method of the hard coat film of this invention is demonstrated.
In the method for producing a hard coat film of the present invention, a coating process in which a hard coat layer-forming composition is dissolved in a solvent is applied on a transparent substrate, and the paint applied on the transparent substrate is dried. It includes a drying step, a curing step of irradiating the coating material with ionizing radiation to form a hard coat layer, and a heating step of heating a transparent substrate provided with the hard coat layer.

(Coating process)
The application step is a step of applying a paint obtained by dissolving the hard coat layer forming composition in a solvent onto a transparent substrate.
Examples of the solvent used in the coating step include a solvent capable of dissolving a transparent substrate, particularly cellulose triacetate (solvent A), and a solvent that does not swell or dissolve cellulose triacetate (solvent B).
Examples of the solvent A include methyl acid, methyl acetate, N-methylpyrrolidone, dimethylformamide, dioxane, dioxolane, methylene chloride, chloroform, tetrachloroethane, dimethyl sulfoxide and the like.
Examples of the solvent B include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, methyl glycol, tetrahydrofuran, and propylene carbonate.
Conventionally, the solvent A is often used for the purpose of improving the adhesion between the hard coat layer and the substrate. However, when the solvent A is used as described above, the hardness of the hard coat layer may be lowered. As a cause of this, it is considered that when a soft base material is dissolved, the base material is dissolved or dispersed in the hard coat layer, and as a result, the hardness of the hard coat layer is lowered. Therefore, in the present invention, it is more preferable to use the solvent B. In particular, methyl isobutyl ketone is preferable.
As for the compounding quantity of a solvent, 10-95 mass% is preferable in 100 mass% of coating materials.

  As a coating method, each component of the composition for forming a hard coat layer and a solvent are appropriately selected, and a paint obtained by mixing at an arbitrary ratio is used as a bar coater, applicator, doctor blade, roll coater, die coater, comma. It can apply | coat using well-known coating means, such as a coater.

(Drying process)
A drying process is a process of drying the coating material apply | coated on the transparent base material.
As the drying method, a known method can be used.

(Curing process)
The curing step is a step of forming a hard coat layer by irradiating the coating material dried in the drying step with ionizing radiation such as ultraviolet rays and electron beams.
As the ionizing radiation, ultraviolet rays are suitable. The ultraviolet irradiation is not particularly limited as long as it includes light having a wavelength of 400 nm or less. For example, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a medium pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, a halogen lamp, or the like can be used. As irradiation conditions, the amount of ultraviolet irradiation is usually preferably 100 to 800 mJ / cm ² .
When the composition for forming a hard coat layer described above contains a radical photopolymerization initiator, the composition for forming a hard coat layer is cured into a hard coat layer by irradiation with ionizing radiation such as ultraviolet rays.

(Heating process)
A heating process is a process of heating a transparent base material.
As a heating method, a known method can be used. Moreover, as heating conditions, 1 minute-120 hours are preferable at 40-150 degreeC. In particular, in the case of 40-69 degreeC, 24 hours-120 hours are preferable, and in the case of 70-150 degreeC, 1 minute-10 minutes are preferable. If the heating time is shorter than the above range when the heating temperature is low (40 to 69 ° C.), the hardness is not sufficiently improved. On the other hand, when the heating temperature is high (70 to 150 ° C.), if the heating time is longer than the above range, the substrate tends to be deformed, which is not preferable.

In the present invention, if necessary after the heating step, a functional layer 13 may be provided on the hard coat layer 11 of the laminate 10 as shown in FIG. Examples of the functional layer 13 include those having antireflection performance, antistatic performance, antifouling performance, antiglare performance, electromagnetic wave shielding performance, infrared absorption performance, ultraviolet absorption performance, color correction performance, and the like. Specific examples include an antireflection layer, an antistatic layer, an antifouling layer, an antiglare layer, an electromagnetic wave shielding layer, an infrared absorption layer, an ultraviolet absorption layer, and a color correction layer.
These functional layers may be a single layer or a plurality of layers. For example, in the case of the antireflection layer, it may be composed of a single low refractive index layer, or may be composed of a plurality of layers by repeating a low refractive index layer and a high refractive index layer.
Moreover, the functional layer 13 may have a plurality of functions in one layer, such as an antireflection layer having antifouling performance.
In addition, as a method for providing the functional layer, a known method can be used.

  The hard coat film thus obtained can be bonded to various display surfaces such as a liquid crystal display, a plasma display, and a CRT display, for example, and a display having excellent scratch resistance can be provided.

  As mentioned above, the composition for hard-coat layer formation of this invention contains a blocked isocyanate compound (D). Therefore, by carrying out the heating step after the curing step in the production of the hard coat film, the thermal crosslinking reaction proceeds in the hard coat layer. Therefore, since the present invention combines a thermal crosslinking reaction with a curing reaction, the pencil hardness of the hard coat film is improved as compared with the conventional method in which the heating step is not performed (only the curing reaction).

In addition, according to the method for producing a hard coat film of the present invention, the heating step is carried out after the curing step, so that the thermal crosslinking reaction proceeds and the moisture contained in the transparent substrate is reduced. Increased hardness. As a result, the hardness of the hard coat film is also improved.
Furthermore, even if the solvent remains in the drying step, the solvent can be completely removed by the heating step. In addition, even if the hard coat film curls due to curing shrinkage of the hard coat layer, it is possible to reduce curl by heating in a state where force is applied in the opposite direction to the curled surface. .

  Although the test example of this invention is shown below, it is not necessarily limited to this. In addition, since the composition for forming a hard coat layer used in the examples is extremely sensitive to light, it is necessary to prevent exposure to unnecessary light such as natural light, and all operations are performed under a yellow or red light. went.

[Materials used]
Common materials used in the following examples and comparative examples are as follows.
<Composition for forming hard coat layer>
Polyfunctional (meth) acrylic monomer (A): urethane acrylate (manufactured by Kyoeisha Chemical Co., Ltd., “UA-306H”).
Polyfunctional (meth) acrylic monomer (A): urethane acrylate (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., “UV-1700B”).
(Meth) acrylic monomer (B) having a hydroxyl group: acrylic monomer (manufactured by Kyoeisha Chemical Co., Ltd., “PE-3A”).
(Meth) acrylic monomer (B) having a hydroxyl group: dipentaerythritol pentaacrylate (manufactured by Kyoeisha Chemical Co., Ltd.).
(Meth) acrylic monomer (B) having a hydroxyl group: Acrylic monomer (manufactured by Kyoeisha Chemical Co., Ltd., “HEMA”).
Photoradical polymerization initiator (C): Irgacure 184 (manufactured by Ciba Specialty Chemicals)
Block isocyanate compound (D): Karenz MOI-BP (manufactured by Showa Denko KK).
Block isocyanate compound (D): Karenz MOI-BM (manufactured by Showa Denko KK).

[Evaluation methods]
The performance of the hard film was evaluated according to the method shown below.
(1) Haze
Measurement was performed according to JIS-K7105 using NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.
(2) Total light transmittance Measurement was performed according to JIS-K7105 using NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.
(3) Pencil hardness Evaluation was performed according to JIS-K5400.
(4) Scratch resistance Using # 0000 steel wool, it was reciprocated 10 times while applying a load of 250 g / cm ² to confirm the presence or absence of scratches.

[Example 1]
Each component of the hard coat layer-forming composition in the blending amount (parts by mass) shown in Table 1 and a solvent were stirred and mixed to prepare a paint.
Next, the paint obtained previously so that the film thickness of the hard coat layer formed by curing on the cellulose triacetate film substrate (Fuji Photo Film Co., Ltd., film thickness: 80 μm) is 12 μm. Was applied by a bar coating method (application process). Thereafter, the paint is dried (drying process), and a hard coat layer is formed by irradiating with 400 mJ / cm ² ultraviolet rays with a metal halide lamp (curing process), followed by heating at 100 ° C. for 3 minutes (heating process). A hard coat film was produced.
The obtained hard coat film was evaluated for haze, total light transmittance, scratch resistance test, and pencil hardness. The results are shown in Table 1.

[Examples 2 to 5]
A hard coat film was produced in the same manner as in Example 1 except that the components of the composition for forming a hard coat layer were changed to those shown in Table 1, and each evaluation was performed. The results are shown in Table 1.

[Example 6]
A hard coat film was produced in the same manner as in Example 1 except that the heating temperature in the heating step was changed to 50 ° C. and the heating time was changed to 100 hours, and each evaluation was performed. The results are shown in Table 1.

[Comparative Example 1]
A hard coat film was produced in the same manner as in Example 1 except that the heating step was not performed, and each evaluation was performed. The results are shown in Table 2.

[Comparative Example 2]
A hard coat film was produced in the same manner as in Example 1 except that the blending amount of the polyfunctional (meth) acrylic monomer (A) was changed to the value shown in Table 1 and the blocked isocyanate compound (D) was not blended. Each evaluation was carried out. The results are shown in Table 2.

[Comparative Example 3]
The blending amount of the polyfunctional (meth) acrylic monomer (A) was changed to the values shown in Table 1, the blocked isocyanate compound (D) was not blended, and the heating step was not performed. A hard coat film was produced and evaluated. The results are shown in Table 2.

As is clear from Table 1, the hard cord films obtained in the examples had good haze, total light transmittance, and scratch resistance, and the pencil hardness was improved as compared with the comparative examples. Moreover, it turned out that these characteristics do not depend on the kind of the polyfunctional (meth) acrylic monomer (A) (urethane acrylate), the (meth) acrylic monomer (B) having a hydroxyl group, or the blocked isocyanate compound (D).
On the other hand, since the hard coat film of Comparative Example 1 was not subjected to the heating step after the curing step, the pencil hardness was significantly inferior to that of the example.
Since the hard coat film of Comparative Example 2 did not contain the blocked isocyanate compound (D), the pencil hardness was inferior to that of the Examples.
In the hard coat film of Comparative Example 3, the composition for forming the hard coat layer did not contain the blocked isocyanate compound (D), and the overheating step was not performed after the curing step, so that the pencil hardness was significantly inferior to the examples. It was.

It is sectional drawing which shows an example of the hard coat film of this invention.

Explanation of symbols

1: Hard coat film 10: Laminate 11: Hard coat layer 12: Transparent substrate 13: Functional layer

Claims (10)

  A polyfunctional (meth) acrylic monomer (A), a (meth) acrylic monomer (B) having a hydroxyl group, a radical photopolymerization initiator (C), and a blocked isocyanate compound (D) that generates an isocyanate group by heat treatment, A composition for forming a hard coat layer, comprising:   The composition for forming a hard coat layer according to claim 1, wherein the polyfunctional (meth) acrylic monomer (A) contains a urethane (meth) acrylate monomer and / or an oligomer as a main component.   The content of the polyfunctional (meth) acrylic monomer (A) is 35 to 90% by mass in 100% by mass of the solid content of the hard coat layer forming composition. The composition for forming a hard coat layer as described.   Content of the (meth) acryl monomer (B) which has the said hydroxyl group is 10-50 mass% in solid content 100 mass% of the said composition for hard-coat layer formation, The 1-3 characterized by the above-mentioned. The composition for forming a hard coat layer according to any one of the above.   Content of the said block isocyanate compound (D) is 5-50 mass% in solid content of 100 mass% of the said composition for hard-coat layer formation, The any one of Claims 1-4 characterized by the above-mentioned. Hard coat layer forming composition.   The content of the radical photopolymerization initiator (C) is 0.01 to 10% by mass in 100% by mass of the solid content of the hard coat layer forming composition. The composition for forming a hard coat layer according to any one of the above.   It has the laminated body which laminated | stacked the hard-coat layer which hardened the composition for hard-coat layer formation in any one of Claims 1-6 on the transparent base material, And the film thickness of the said hard-coat layer is A hard coat film having a thickness of 5 to 25 μm.   The hard coat film according to claim 7, wherein the transparent substrate is cellulose triacetate.   The coating process which apply | coated the coating material which melt | dissolved the composition for hard-coat layer formation in any one of Claims 1-6 in a solvent on a transparent base material, and dry the coating material apply | coated on the transparent base material The manufacturing method of the hard coat film characterized by including the drying process, the hardening process which irradiates an ionizing radiation to a coating material and forms a hard-coat layer, and the heating process which heats a transparent base material provided with a hard-coat layer.   The method for producing a hard coat film according to claim 9, wherein the heating step is performed at 40 to 150 ° C. for 1 minute to 120 hours.

Images