JP2017102407A - Hard coat film, polarizing plate and transmissive liquid crystal display using the same, and manufacturing method of hard coat film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coat film that is excellent in adhesion between a support substrate and a hard coat layer and pencil hardness, and can reduce interference fringe caused by a difference in refractive index between the support substrate and hard coat layer.SOLUTION: There is provided a hard coat film comprising a support substrate and a hard coat layer laminated on a single face of the support substrate, wherein the support substrate is formed of a first acrylic photocurable resin having at least one of a urethane skeleton, aromatic ring, and cyclic structure; the hard coat layer is formed of a second acrylic photocurable resin; the support substrate has a tensile strength of 25 to 40 N/mm; the support substrate has a tensile elongation defined by the following formula of 10% or more and a pencil hardness of 2H or more. Tensile elongation={(length at break)-(initial length before pulling)}/initial length before pulling.SELECTED DRAWING: None

Description

  INDUSTRIAL APPLICABILITY The present invention can be used as a protective film for liquid crystal display devices, plasma display devices, electrochromic display devices, light emitting diode display devices, EL display devices, display device parts such as touch panels, and can also be used as a functional film. It relates to a hard coat film.

  A polarizing plate protective film for a liquid crystal display and a protective film for a polarizing plate used for an organic EL display or the like are formed with a resin layer in order to have 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 particular, the hard coat layer is indispensable for display applications and is used not only as a single layer but also as a lower layer of the antireflection layer.

  Among plastic substrate films having high transparency, a triacetyl cellulose (TAC) film is mainly used as a substrate film for an optical laminate for a liquid crystal display (LCD) because of its excellent transparency.

  However, in the conventional hard coat film using a TAC film as a supporting base material, even if the hardness is sufficient, interference fringes are generated due to the difference in refractive index between the TAC film and the hard coat layer. When used in an image display device such as a liquid crystal display, the visibility is deteriorated.

  Therefore, there is a report that attempts to improve interference fringes by interposing an optical adjustment layer between the TAC film and the hard coat layer (for example, Patent Document 1).

Japanese Patent No. 5340591

  However, in the method of providing the intermediate layer in this way, the difference in refractive index between the two layers cannot be completely eliminated, so that interference fringes substantially remain. Moreover, sufficient hardness cannot be obtained by providing the intermediate layer.

  Moreover, since the process of forming an intermediate | middle layer is needed, productivity will fall.

  The present invention provides a hard coat film that is excellent in adhesion between the support substrate and the hard coat layer and pencil hardness, and that can reduce interference fringes caused by a difference in refractive index between the support substrate and the hard coat layer. It is an object of the present invention to provide a method for producing a polarizing plate, a transmissive liquid crystal display, and a hard coat film.

The present invention relates to a hard coat film comprising a support substrate and a hard coat layer laminated on one side of the support substrate. The support substrate is made of an acrylic first photocurable resin having at least one of a urethane skeleton, an aromatic ring, or a cyclic structure, and the hard coat layer is made of an acrylic second photocurable resin, The tensile strength of the supporting substrate is 25 to 40 N / mm ² , the tensile elongation of the supporting substrate defined by the following formula (I) is 10% or more, and the pencil hardness of the hard coat film is 2H or more. is there.
Tensile elongation = {(Length at break) − (Initial length before tension)} / Initial length before tension
... Formula (I)

  The thickness of the hard coat layer is preferably 2 μm or more and 15 μm or less.

  Moreover, it is good in the thickness of a support base material being 20 micrometers or more and 100 micrometers or less.

  The polarizing plate according to the present invention includes the hard coat film described above.

  The transmissive display according to the present invention includes the hard coat film described above.

Moreover, this invention relates to the manufacturing method of the hard coat film which consists of a support base material and the hard-coat layer laminated | stacked on the single side | surface of the support base material. The method for producing a hard coat film according to the present invention comprises a (meth) acryloyl group, a first photocurable resin having at least one of a urethane skeleton, an aromatic ring, and a cyclic structure, and a photopolymerization initiator. The coating film of the first photocurable composition is irradiated with ultraviolet rays at an exposure amount of 50 to 150 mJ / cm ² to form a supporting substrate, and two or more ( A coating film is formed by applying a second photocurable composition containing a second photocurable resin having a (meth) acryloyl group and a photopolymerization initiator, and the second photocurable composition And a step of irradiating the coating film with ultraviolet rays at an exposure amount of 200 mJ / cm ² or more to form a hard coat layer.

Moreover, the tensile strength of the resin molded product when cured by irradiating ultraviolet rays at an exposure amount of 300 mJ / cm ² to the coating film of the first photocurable composition is 45 N / mm ² or more, and It is preferable that the tensile elongation of the resin molded body defined by the formula (I) is 5% or more.
Tensile elongation = {(Length at break) − (Initial length before tension)} / Initial length before tension
... Formula (I)

  According to the present invention, a hard coat film that is excellent in adhesion between the support substrate and the hard coat layer, and pencil hardness, and can reduce interference fringes due to a difference in yield rate between the support substrate and the hard coat layer, A polarizing plate, a transmissive liquid crystal display, and a method for producing a hard coat film using the same can be provided.

As a result of intensive studies, the inventor of the present application has found that a support base material made of an acrylic first photocurable resin having at least one of a urethane skeleton, an aromatic ring, and a cyclic structure, and an acrylic layer laminated on one side of the support base material. It consists of a second photo-curable resin of the system and consists of a hard coat layer, the supporting substrate has a tensile strength of 25 to 40 N / mm ² , and the tensile elongation of the supporting substrate defined by the following formula (I) A hard coat film having a degree of 10% or more and a pencil hardness of 2H or more was invented.
Tensile elongation = {(Length at break) − (Initial length before tension)} / Initial length before tension
... Formula (I)

  The photo-curable resin (photo-curable substance) used in the present invention refers to a resin whose main component is a resin that is cured through a crosslinking reaction by irradiation with active rays such as ultraviolet rays and electron beams.

  In the present specification, “(meth) acrylate” refers to both acrylate and methacrylate, and “(meth) acryloyl group” refers to both acryloyl group and methacryloyl group.

<Support base material>
The supporting base material is formed by applying a coating liquid of a first photocurable resin composition containing an acrylic first photocurable resin and a photopolymerization initiator on the support, and photocuring the coating film. And a cured film obtained by peeling off from the support. As the first photocurable resin, one having one or more (meth) acryloyl groups and at least one of a urethane skeleton, a cyclic structure, and an aromatic ring is used. The resin material specified for the first photocurable resin composition may be one kind or a mixture of plural kinds. As an example of a photo-curable resin that can be used as a support substrate, ACMO (KJ Chemicals) or the like can be used for an acrylate having one (meth) acryloyl group, and 2 to 3 (meth) acryloyl can be used. Examples of the acrylate having a group include purple light UV-7000B (Nippon Synthetic Chemical Industry), purple light UV-3520EA (Nippon Synthetic Chemical Industry), light acrylate DCP-4EO-A (Kyoeisha Chemical), Aronix M-211B (Toagosei), Epoxy ester 3002A (Kyoeisha Chemical) or the like can be used.

  A (meth) acrylate containing a urethane skeleton and a cyclic structure is relatively excellent in strength characteristics and toughness.

The first photocurable composition is cured such that the tensile strength of the resin molded product when cured at an exposure amount of 300 mJ / cm ² is 45 N / mm ² or more and the elongation is 5% or more. It is preferable to select a resin material to be combined with the functional resin as necessary. Under these conditions, it can be used practically as a hard coat film.

  In addition, the photopolymerization initiator used in the coating solution of the first photocurable resin composition in the present invention is not particularly limited, but 1-hydroxycyclohexylphenylketone (particularly less colored by curing of the transparent resin) Trade name: Irgacure (registered trademark) 184 (manufactured by BASF)) can be preferably used. Further, a surface-curing polymerization initiator α-hydroxyketone, for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2- Hydroxy-2-methyl-1-propan-1-one, α-aminoketone 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one with high molar extinction coefficient and internal curing system Acyl phosphine oxide, for example, bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide, and α-amino ketones having an absorption region in the h-line, such as 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -butanone-1 or the like may be used in combination.

  In addition to those shown above, for example, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, etc., initiators having surface-curing and internal-curing characteristics Can be appropriately selected.

  The amount of the photopolymerization initiator used is preferably 0.5 to 15% by mass based on the total solid content of the photocurable resin, and the film hardness tends to be low even if it is more or less than this range. It is in. In particular, when it is too much, the coating film may be colored.

  Further, n-butylamine, triethylamine, poly-n-butylphosphine or the like may be mixed and used as a photosensitizer.

  In the present invention, as a support used for curing the photopolymerizable composition, a roll-shaped metal body, polyethylene terephthalate (PET film), or the like can be used. After applying the photopolymerizable composition, there is no particular limitation as long as the resin molded body cured after ultraviolet curing can be easily peeled without deformation of the support in a process such as ultraviolet curing.

  In the coating liquid prepared by dissolving the first photocurable resin and the photopolymerization initiator in a solvent, an additive is added for antifouling property, slipperiness imparting, defect prevention and particle dispersibility improvement. Also good. For example, polyether-modified polymethylalkylsiloxane, polyether-modified polydimethylsiloxane, fluorine-modified polymer, acrylic copolymer, polyester-modified acrylic-containing polydimethylsiloxane, silicon-modified polyacryl, and the like can be used.

  Moreover, a well-known method can be used as a coating method of the said coating liquid to the support body. Specifically, bar coating method, dip coating method, flow coating method, spray coating method, roll coating method, gravure roll coating method, air doctor coating method, blade coating method, wire doctor coating method, knife coating method, reverse coating A method such as a coating method, a transfer roll coating method, a micro gravure coating method, a kiss coating method, a cast coating method, a slot orifice coating method, a calendar coating method, or a die coating method can be used.

  The light source for curing the photocurable resin by a photocuring reaction to form a cured film is not particularly limited as long as it is a light source that generates ultraviolet rays. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, an electrodeless discharge tube, or the like can be used.

As irradiation conditions, the ultraviolet irradiation amount is set to 50 to 150 mJ / cm ² . By leaving the unreacted part by curing the support base material layer at a low exposure amount, it is possible to expect an improvement in adhesion during the formation of the hard coat layer.

It is preferable that the tensile strength of the supporting substrate is 25 to 40 N / mm ² and the tensile elongation of the supporting substrate defined by the following formula (I) is 10% or more.
Tensile elongation = {(Length at break) − (Initial length before tension)} / Initial length before tension
... Formula (I)
If it is this range, the hard coat film excellent in the intensity | strength characteristic and toughness can be obtained.

  The thickness of the supporting substrate is preferably 20 μm or more and 100 μm or less. If it is this range, the hard coat film which has thinness and intensity | strength can be obtained.

  The photocurable resin layer obtained as described above can contain fine particles of inorganic or organic compounds for preventing blocking, imparting hardness, imparting antiglare properties, imparting antistatic performance, or adjusting the refractive index.

  As the inorganic fine particles used, it is possible to use oxides such as silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide, tin oxide and antimony pentoxide, and composite oxides such as antimony-doped tin oxide and phosphorus-doped tin oxide. it can. In addition, calcium carbonate, talc, clay, kaolin, calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and the like can also be used.

  The organic fine particles include polymethyl methacrylate acrylate resin powder, acrylic-styrene resin powder, polymethyl methacrylate resin powder, silicon resin powder, polystyrene powder, polycarbonate powder, melamine resin powder, polyolefin resin powder, etc. Can be used.

  The average particle size of these fine particle powders is preferably 5 nm to 20 μm, and more preferably 10 nm to 10 μm. These fine particles can be used in combination of two or more.

  The support substrate obtained in the present invention is further provided with antireflection performance, antistatic performance, antifouling performance, antiglare performance, electromagnetic wave shielding performance, infrared absorption performance, ultraviolet absorption performance, or color correction performance as necessary. Etc. may be laminated. These functional layers may be a single layer or a plurality of layers. For example, the antireflection layer 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. Further, the functional layer may have a plurality of functions as a single layer, such as an antireflection layer having antifouling performance.

  In this invention, the example about the case where a hard-coat layer is formed in a support base material is shown. The hard coat forming surface may be either surface of the support substrate.

<Hard coat layer>
The hard coat layer is formed by applying a coating solution of a second photocurable resin composition containing an acrylic second photocurable resin and a photopolymerization initiator to a supporting substrate, and photocuring the coating film. It consists of the cured film obtained. As a 2nd photocurable resin used for a hard-coat layer by this invention, the acrylate which has a polyfunctional (2 or more) (meth) acryloyl group is used. As an example, UA-306I (Kyoeisha Chemical) or light acrylate DPE-6A (Kyoeisha Chemical) can be used.

  Further, the photopolymerization initiator used in the coating liquid in the present invention is not particularly limited, but 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure (registered trademark) 184 (BASF), which is particularly less colored by curing of the transparent resin, is used. Manufactured)). Further, a surface-curing polymerization initiator α-hydroxyketone, for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2- Hydroxy-2-methyl-1-propan-1-one, α-aminoketone 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one with high molar extinction coefficient and internal curing system Acyl phosphine oxide, for example, bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide, and α-amino ketones having an absorption region in the h-line, such as 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -butanone-1 or the like may be used in combination.

  In addition to the above-mentioned ones, for example, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, etc., which have characteristics of a surface curing system and an internal curing system. Can be selected as appropriate.

  The amount of the photopolymerization initiator used is preferably 0.5 to 15% by mass based on the total solid content of the photocurable resin, and the film hardness tends to be low even if it is more or less than this range. In particular, when it is too much, the coating film may be colored.

  Further, n-butylamine, triethylamine, poly-n-butylphosphine or the like may be mixed and used as a photosensitizer.

  In the coating liquid prepared by dissolving the second photocurable resin and the photopolymerization initiator in a solvent, an additive is added for antifouling property, slipperiness imparting, defect prevention and particle dispersibility improvement. Also good. Examples of use are the same as those shown for the support substrate.

  Further, the coating method of the coating liquid onto the supporting substrate and the light source at the time of photocuring are the same as those shown for the supporting substrate.

As the irradiation condition, the ultraviolet irradiation amount is set to 200 mJ / cm ² or more. By curing the hard coat layer at a high exposure amount, crosslinking between the unreacted portion of the support substrate and the hard coat layer is promoted, and it can be expected that a hard coat film having improved adhesion and high pencil hardness can be obtained.

  The thickness of the hard coat layer is preferably 2 μm or more and 15 μm or less. Within this range, a stable hard coat layer can be formed.

  The hard coat layer obtained as described above can contain fine particles of inorganic or organic compounds for blocking prevention, hardness imparting, antiglare property, antistatic performance imparting, or refractive index adjustment. These usage examples are the same as those shown for the support substrate.

  The hard coat film described above is excellent in adhesion between the hard coat layer and the support substrate, has good pencil hardness, and has few interference fringes. By mounting this hard coat film on a polarizing plate or a transmissive liquid crystal display, It is expected that a liquid crystal display device with good visibility can be provided.

  Examples will be described below. However, the present invention is not limited to the following examples.

  Evaluation methods and evaluation criteria for each item described below are as follows.

<Support base material>
(1) Tensile property test A strip-shaped film sample of 100 mm x 15 mm is formed from the obtained support base material (photo-curable resin molding), and measurement is started using a small tabletop tester EZ-LX manufactured by Shimadzu Corporation The test was conducted at a distance between chucks of 50 mm and a tensile speed of 5 mm / min. The tensile elongation was calculated using the following formula (I).
Tensile elongation = {(Length at break) − (Initial length before tension)} / Initial length before tension
... Formula (I)

<Hard coat layer>
(1) Adhesion test About the obtained hard coat film, an optical film according to the adhesion test method (cross cut tape method) of paint general test method JIS-K5600-5-6: 1999 (ISO 2409: 1992) Evaluation was made based on the number of remaining coating films on the surface.
The evaluation confirmed visually is made into three stages of ○, △, ×,
○: Peeling cannot be confirmed Δ: Peeling of 20 squares or less can be confirmed ×: Peeling of 20 squares or more can be confirmed.

(2) Pencil hardness test Using a Clemens type scratch hardness tester (manufactured by Tester Sangyo Co., Ltd., HA-301) according to JIS-K5600-5-4: 1999 (ISO / DIS15184: 1996), 500 g on the surface of the hard coat film. A test was performed using a pencil (Mitsubishi UNI) having a hardness of F to 4H to which a load of 1 mm was applied, and the change in appearance due to scratches was visually evaluated.

(3) Interference fringe evaluation The opposite surface on which the hard coat film was formed was rubbed with sandpaper, then a matte black paint was applied, and the hard coat film was observed and evaluated from the hard coat layer forming side. As evaluation criteria,
○: Interference fringes are not visible ×: Interference fringes are visible.

  In forming the supporting substrate, urethane 1 was synthesized as follows with reference to urethane acrylate (C-1) described in JP2013-159691A.

[Production of Urethane 1]
A reaction vessel equipped with a condenser, a stirrer, and a thermometer was charged with 31.5 parts by weight of isophorone diisocyanate and 0.1 parts by weight of dibutyltin dilaurate and heated to 50 ° C. Next, 68.4 parts by weight of ε-caprolactone 1 mol-modified 2-hydroxyethyl acrylate (manufactured by Daicel Chemical Industries, Ltd. “PLACCEL FA1DDM”) was added dropwise over 1 hour, and the reaction was performed by stirring at 90 ° C. for 10 hours. . When the amount of residual isocyanate in this reaction solution was measured using FT-IR, the urethanization reaction was quantitatively performed, and finally the isocyanate disappeared, and urethane acrylate represented by the following chemical formula (hereinafter, Urethane 1) 99.9 parts by weight were obtained. In the formula, A is an acryloyloxy group.

<Example 1>
[Supporting substrate]
・ Urethane 1 57.1 parts by weight ・ Irgacure 184 (BASF) 2.9 parts by weight ・ Methyl ethyl ketone 40 parts by weight is stirred and mixed, and a cured film is applied to a PET film (Lumirror T60-75 μm: Toray) by a bar coating method. The coating was applied to a thickness of 20 μm, and the coating film was cured by irradiating ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² . When the photocured coating film was peeled from the PET film and the tensile properties of the obtained support substrate were measured, the strength was 65 N / mm ² and the tensile elongation was 5%. When the tensile properties of the support substrate obtained by changing the exposure condition to an exposure amount of 50 mJ / cm ² were measured, the strength was 30 N / mm ² and the tensile elongation was 25%. In Example 1, a hard coat layer was formed using a supporting base material produced at an exposure amount of 50 mJ / cm ² .

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 19.05 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 19.05 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Coating with 60 parts by weight of methyl ethyl ketone stirred and mixed The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 2 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 250 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, no peeling was confirmed, the pencil hardness was 2H, and no interference fringes were visible.

<Example 2>
[Supporting substrate]
-Urethane 1 40 parts by weight-Purple light UV-7000 (Nippon Gosei Chemical Industry Co., Ltd.) 17.1 parts by weight-Irgacure 184 (BASF) 2.9 parts by weight-Methyl ethyl ketone 40 parts by weight was stirred and mixed with a PET film ( The film was applied to Lumirror T60-75 μm (Toray) so as to have a cured film thickness of 45 μm by a bar coating method, and the coating film was cured by irradiating ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² . When the photocured coating film was peeled from the PET film and the tensile properties of the obtained support substrate were measured, the strength was 60 N / mm ² and the tensile elongation was 10%. When the tensile properties of the support substrate obtained by changing the exposure condition to an exposure amount of 100 mJ / cm ² were measured, the strength was 35 N / mm ² and the tensile elongation was 40%. In Example 2, a hard coat layer was formed using a support substrate produced at an exposure amount of 100 mJ / cm ² .

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 15.2 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 22.9 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Coating with 60 parts by weight of methyl ethyl ketone stirred and mixed The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 5 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 200 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, no peeling was confirmed, the pencil hardness was 2H, and no interference fringes were visible.

<Example 3>
[Supporting substrate]
-Urethane 1 40 parts by weight-Purple light UV-3520EA (Nippon Synthetic Chemical Industry) 17.1 parts by weight-Irgacure 184 (BASF) 2.9 parts by weight-Methyl ethyl ketone 40 parts by weight was stirred and mixed with a PET film ( The film was applied to Lumirror T60-75 μm (Toray) by a bar coating method so as to have a cured film thickness of 60 μm, and the coating film was cured by irradiating ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² . When the photocured coating film was peeled from the PET film and the tensile properties of the obtained support substrate were measured, the strength was 55 N / mm ² and the tensile elongation was 25%. When the tensile properties of the supporting substrate obtained by changing the exposure condition to an exposure amount of 100 mJ / cm ² were measured, the strength was 30 N / mm ² and the tensile elongation was 30%. In Example 3, a hard coat layer was formed using a support substrate produced at an exposure amount of 100 mJ / cm ² .

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 19.05 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 19.05 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Coating with 60 parts by weight of methyl ethyl ketone stirred and mixed The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 10 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, no peeling was confirmed, the pencil hardness was 2H, and no interference fringes were visible.

<Example 4>
[Supporting substrate]
・ Epoxy ester 3002A (Kyoeisha Chemical Co., Ltd.) 57.1 parts by weight ・ Irgacure 184 (BASF) 2.9 parts by weight ・ Methyl ethyl ketone 40 parts by weight was stirred and mixed with a coating solution on a PET film (Lumilar T60-75 μm: Toray). The coating film was applied so as to have a cured film thickness of 60 μm, and the coating film was cured by irradiating with an ultraviolet ray at an exposure amount of 300 mJ / cm ² with a metal halide lamp. When the photocured coating film was peeled from the PET film and the tensile properties of the obtained support substrate were measured, the strength was 45 N / mm ² and the tensile elongation was 20%. When the tensile properties of the support substrate obtained by changing the exposure condition to an exposure amount of 150 mJ / cm ² were measured, the strength was 30 N / mm ² and the tensile elongation was 30%. In Example 4, a hard coat layer was formed using a support substrate produced at an exposure amount of 150 mJ / cm ² .

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 11.4 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 26.7 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Methyl ethyl ketone 60 parts by weight The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 10 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, no peeling was confirmed, the pencil hardness was 2H, and no interference fringes were visible.

<Example 5>
[Supporting substrate]
ACMO (KJ Chemicals) 40 parts by weight Purple light UV-7000 (Nippon Synthetic Chemical Industry) 17.1 parts by weight Irgacure 184 (BASF) 2.9 parts by weight Methyl ethyl ketone 40 parts by weight A PET film (Lumirror T60-75 μm: Toray) was applied by a bar coating method so as to have a cured film thickness of 45 μm, and the coating film was cured by irradiating ultraviolet rays with an exposure amount of 300 mJ / cm ² with a metal halide lamp. When the photocured coating film was peeled from the PET film and the tensile properties of the obtained support substrate were measured, the strength was 55 N / mm ² and the tensile elongation was 80%. When the tensile properties of the support substrate obtained by changing the exposure condition to an exposure amount of 100 mJ / cm ² were measured, the strength was 30 N / mm ² and the tensile elongation was 100%. In Example 5, a hard coat layer was formed using a support substrate produced at an exposure amount of 100 mJ / cm ² .

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 19.05 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 19.05 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Coating with 60 parts by weight of methyl ethyl ketone stirred and mixed The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 5 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, no peeling was confirmed, the pencil hardness was 2H, and no interference fringes were visible.

<Example 6>
[Supporting substrate]
・ Aronix M-211B (Toagosei) 40 parts by weight ・ Light acrylate DCP-4EO-A (Kyoeisha Chemical Co., Ltd.) 17.1 parts by weight ・ Irgacure 184 (BASF) 2.9 parts by weight ・ Methyl ethyl ketone 40 parts by weight were stirred and mixed. The coating solution was applied to a PET film (Lumirror T60-75 μm: Toray) so as to have a cured film thickness of 100 μm by the bar coating method, and the coating film was cured by irradiating ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² . . When the photocured coating film was peeled from the PET film and the tensile properties of the obtained supporting substrate were measured, the strength was 45 N / mm ² and the tensile elongation was 7%. When the tensile properties of the support substrate obtained by changing the exposure condition to an exposure dose of 150 mJ / cm ² were measured, the strength was 30 N / mm ² and the tensile elongation was 15%. In Example 6, a hard coat layer was formed using a support substrate produced at an exposure amount of 150 mJ / cm ² .

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 11.4 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 26.7 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Methyl ethyl ketone 60 parts by weight The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 15 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, no peeling was confirmed, the pencil hardness was 2H, and no interference fringes were visible.

<Comparative Example 1>
[Supporting substrate]
-Urethane 1 40 parts by weight-Purple light UV-7000 (Nippon Gosei Chemical Industry Co., Ltd.) 17.1 parts by weight-Irgacure 184 (BASF) 2.9 parts by weight-Methyl ethyl ketone 40 parts by weight was stirred and mixed with a PET film ( The film was applied to Lumirror T60-75 μm (Toray) so as to have a cured film thickness of 45 μm by a bar coating method, and the coating film was cured by irradiating ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² . When the photocured coating film was peeled from the PET film and the tensile properties of the obtained support substrate were measured, the strength was 60 N / mm ² and the tensile elongation was 10%. When the tensile properties of the support substrate obtained by changing the exposure condition to the exposure amount of 200 mJ / cm ² were measured, the strength was 50 N / mm ² , the tensile elongation was 20%, and the UV irradiation amount was large. A high-strength support substrate was formed. In Comparative Example 1, a hard coat layer was formed using a supporting base material produced at an exposure amount of 200 mJ / cm ² .

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 15.2 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 22.9 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Coating with 60 parts by weight of methyl ethyl ketone stirred and mixed The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 5 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 200 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, since the curing of the support base material has progressed too much, the adhesion decreased, peeling of 20 squares or more was confirmed, the pencil hardness was 2H, and interference fringes were confirmed.

<Comparative example 2>
[Supporting substrate]
-Urethane 1 40 parts by weight-Purple light UV-7000 (Nippon Gosei Chemical Industry Co., Ltd.) 17.1 parts by weight-Irgacure 184 (BASF) 2.9 parts by weight-Methyl ethyl ketone 40 parts by weight was stirred and mixed with a PET film ( The film was applied to Lumirror T60-75 μm (Toray) so as to have a cured film thickness of 45 μm by a bar coating method, and the coating film was cured by irradiating ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² . When the photocured coating film was peeled from the PET film and the tensile properties of the obtained support substrate were measured, the strength was 60 N / mm ² and the tensile elongation was 10%. When the tensile properties of the support substrate obtained by changing the exposure condition to an exposure amount of 100 mJ / cm ² were measured, the strength was 35 N / mm ² and the tensile elongation was 40%. In Comparative Example 2, a hard coat layer was formed using a supporting base material produced at an exposure amount of 100 mJ / cm ² .

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 15.2 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 22.9 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Coating with 60 parts by weight of methyl ethyl ketone stirred and mixed The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 5 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 50 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, since the UV irradiation amount at the time of hard coat formation was small, the adhesion was reduced, peeling of 20 squares or more was confirmed, the pencil hardness was reduced to H, and interference fringes were also observed. confirmed.

<Comparative Example 3>
[Supporting substrate]
・ Light acrylate 3EG-A (Kyoeisha Chemical Co., Ltd.) 57.1 parts by weight ・ Irgacure 184 (BASF) 2.9 parts by weight ・ A coating solution obtained by stirring and mixing 40 parts by weight of methyl ethyl ketone was added to a PET film (Lumirror T60-75 μm: Toray). The coated film was cured by irradiating with UV light at a dose of 300 mJ / cm ² with a metal halide lamp. When the photocured coating film was peeled from the PET film and the tensile properties of the obtained support substrate were measured, the strength was 10 N / mm ² and the tensile elongation was 10%. When the tensile properties of the support substrate obtained by changing the exposure condition to an exposure amount of 100 mJ / cm ² were measured, the strength was 5 N / mm ² , the tensile elongation was 15%, and light acrylate 3EG-A was urethane. Since it does not have any cyclic skeleton, a low-strength supporting substrate was formed. In Comparative Example 3, a hard coat layer was formed using a resin molded body produced at an exposure amount of 100 mJ / cm ² as a supporting substrate.

[Hard coat layer]
・ UA-306I (Kyoeisha Chemical Co., Ltd.) 15.2 parts by weight ・ Light acrylate DPE-6A (Kyoeisha Chemical Co., Ltd.) 22.9 parts by weight ・ Irgacure 184 (BASF) 1.9 parts by weight ・ Coating with 60 parts by weight of methyl ethyl ketone stirred and mixed The liquid was applied to one side of the supporting substrate by a bar coating method so as to have a cured film thickness of 5 μm, and irradiated with ultraviolet rays with a metal halide lamp at an exposure amount of 300 mJ / cm ² to obtain a hard coat film. As a result of the adhesion test of the hard coat film, peeling was not confirmed and no interference fringes were seen, but the pencil hardness was reduced to F because the strength of the supporting substrate was weak.

  The evaluation results of Examples 1 to 6 and Comparative Examples 1 to 3 are summarized in Table 1.

  The hard coat film of the present invention can improve the adhesion between the support substrate and the hard coat layer by gradually increasing the exposure amount in the support substrate formation step and the hard coat layer formation step. it can.

  In addition, since the hard coat film of the present invention uses the same acrylic photocurable resin for the support base and the hard coat layer, the refractive index difference between the two layers is small and interference fringes can be prevented. . Moreover, since it is not necessary to provide an intermediate | middle layer between a base material and a hard-coat layer, productivity improves.

  Further, the hard coat film of the present invention uses (meth) acrylate containing at least one of urethane skeleton, aromatic ring and cyclic structure for the support base material, and has excellent strength characteristics and toughness, so that the pencil hardness is also good. It is.

  The hard coat film according to the present invention can be used as a protective film for liquid crystal display devices, plasma display devices, electrochromic display devices, light emitting diode display devices, EL display devices, and display device parts such as touch panels.

Claims (7)

It consists of a support substrate and a hard coat layer laminated on one side of the support substrate,
The support substrate is made of an acrylic first photocurable resin having at least one of a urethane skeleton, an aromatic ring, or a cyclic structure,
The hard coat layer is made of an acrylic second photocurable resin,
The tensile strength of the supporting substrate is 25 to 40 N / mm ² and the tensile elongation of the supporting substrate defined by the following formula (I) is 10% or more,
A hard coat film having a pencil hardness of 2H or more.
Tensile elongation = {(Length at break) − (Initial length before tension)} / Initial length before tension
... Formula (I)   The hard coat film according to claim 1, wherein a thickness of the hard coat layer is 2 μm or more and 15 μm or less.   The hard coat film according to claim 1, wherein the support base has a thickness of 20 μm or more and 100 μm or less.   A polarizing plate comprising the hard coat film according to claim 1.   A transmissive liquid crystal display comprising the hard coat film according to claim 1. A method for producing a hard coat film comprising a support substrate and a hard coat layer laminated on one side of the support substrate,
A coating film of a first photocurable composition containing a (meth) acryloyl group, a first photocurable resin having at least one of a urethane skeleton, an aromatic ring, and a cyclic structure, and a photopolymerization initiator. On the other hand, a step of irradiating ultraviolet rays at an exposure amount of 50 to 150 mJ / cm ² to form the support substrate;
A coating film is formed by applying a second photocurable composition containing a second photocurable resin having two or more (meth) acryloyl groups and a photopolymerization initiator to one side of the support substrate. And forming the hard coat layer by irradiating the coating film of the second photocurable composition with ultraviolet rays at an exposure amount of 200 mJ / cm ² or more. Production method. The tensile strength of the resin molded product when cured by irradiating ultraviolet rays with an exposure amount of 300 mJ / cm ² to the coating film of the first photocurable composition is 45 N / mm ² or more, and The method for producing a hard coat film according to claim 6, wherein a tensile elongation of the resin molded body defined by the formula (I) is 5% or more.
Tensile elongation = {(Length at break) − (Initial length before tension)} / Initial length before tension
... Formula (I)