JP6455115B2 - Photo-curable resin molding, polarizing plate, and transmissive liquid crystal display - Google Patents

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. The present invention relates to a photocurable resin molded body.

  Resin layers are formed on a polarizing plate protective film for a liquid crystal display and a polarizing plate protective film 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 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.

  A liquid crystal display device is a display element that utilizes the birefringence of liquid crystal molecules. Of the members constituting the liquid crystal display device, those other than the liquid crystal, the phase difference plate and the polarizing plate are often designed as having no phase difference. When the members other than the liquid crystal, the phase difference plate, and the polarizing plate have a minute phase difference, the visibility unique to the liquid crystal display device, particularly the oblique visibility is deteriorated. Therefore, it is desirable that the substrate (support) used in the liquid crystal display device or the like and the coating film have as little retardation as possible.

  Triacetyl cellulose (TAC), polyethylene terephthalate (PET), and the like used as a base material (support) of an optical film generate a phase difference depending on the properties of the base material or the manufacturing process of the base material. For example, when these are used as a base material (support film) for a hard coat of a liquid crystal display, the visibility is likely to be lowered. In recent years, an attempt to reduce the retardation of the base material has been attempted. (For example, refer nonpatent literature 1).

The phase difference is expressed by the following formula (1) and increases in proportion to the film thickness. The birefringence is expressed by the following formula (2). From formula (1), it can be seen that the visibility of the substrate having a phase difference is improved by using a thin film.
Rth = Δn × d (1)
Δn = (2π / 45 kT) × {(ND ² +2) ² / ND} × (σ‖−σ⊥) × σ
... Formula (2)
here,
Δn: birefringence ND: average refractive index σ‖−σ⊥: main polarization difference σ: stress k: Boltzmann constant T: absolute temperature Rth: thickness direction retardation d: film thickness

  Moreover, it is desirable that the coating liquid applied to the substrate also has a small phase difference. In particular, when a thermosetting resin having a large shrinkage is used, the stress σ described in the above formula (2) increases, and as a result, the phase difference increases.

  In recent years, there have been many demands for film thickness reduction. In this case, studies have been made on applying a pressure-sensitive adhesive layer for improving impact resistance to a base film made of an optical functional film for liquid crystal displays (for example, see Patent Document 1).

  On the other hand, in a liquid crystal display device, it is desired to use a base film having a thickness of about half of the conventional thickness (about 60 to 120 μm) for the hard coat film. When a conventional hard coat layer is formed on such a thin substrate, a larger curl is generated in the hard coat film due to curing shrinkage of the hard coat layer. As a result, it becomes difficult to use as a surface protective film. In addition, when the base material is thinned, the strength of the base material itself is lowered, and there is a problem that the base material is easily broken during transportation in the coating process.

  In particular, in triacetyl cellulose (TAC), when forming a coating film, the base material dissolves or swells due to the solvent contained in the coating solution, which may cause brittleness (for example, patents). Reference 2).

JP 2007-156066 A JP 2008-133352 A JP 2013-159691 A

Ryo Suzuki, “Development and Trends of Low Birefringence Optical Film”, Monthly Display, Techno Times, April 2012

  It is an object of the present invention to provide a photocurable resin molded article that is excellent in strength, can be thinned, and can reduce retardation, and a polarizing plate and a transmissive liquid crystal display using the same.

The present invention relates to a photocurable resin molded product obtained by photocuring a photopolymerizable composition, and the photopolymerizable composition contains a photocurable resin and an ultraviolet polymerization initiator, and is photocurable. The resin is composed of two types of acrylates A and B having 2 or 3 (meth) acryloyl groups, and the acrylate A has a urethane skeleton and an aromatic ring or alicyclic structure, in the case tensile strength 40N / mm ² or more, elongation is 10% or less than 3%, acrylates B, alone tensile strength when formed into a resin molded product 5N / mm ² or more 35N / mm ² or less The tensile elongation defined by the following formula (I) is 30% or more, the weight ratio of acrylate A and acrylate B is 90:10 to 10:90, and the thickness of the photocurable resin molded body 15 μm or more and 50 μm or less Der is, and a tensile strength of the photocurable resin molded body is 40N / mm ² or more, the tensile elongation of the photocurable resin molded body is Ru der 10% or more.
Tensile elongation (%) = {(length at break) − (initial length before tension)} × 100 / initial length before tension
... Formula (I)

It is preferable that the retardation Rth in the thickness direction represented by the following formula (II) of the photocurable resin molded body is 2 nm or less.
Rth = {(Nx + Ny) / 2−Nz} × d Formula (II)
Here, Nx is the refractive index in the slow axis direction in the plane of the photocurable resin layer, Ny is the refractive index in the fast axis direction (where Nx ≧ Ny), Nz is the refractive index in the thickness direction, and d is the light. It is the thickness of the curable resin molding.

  The polarizing plate which concerns on this invention is equipped with the above-mentioned photocurable resin molding.

  The transmissive display according to the present invention includes the above-described photocurable resin molded body.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in intensity | strength, and can provide the photocurable resin molding which can be reduced in thickness and reduction of a phase difference, a polarizing plate using this, and a transmissive liquid crystal display.

As a result of intensive studies by the present inventor, the ultraviolet curable resin is composed of two kinds of acrylates A and B having two or three (meth) acryloyl groups, and the acrylate A is composed of a urethane skeleton, an aromatic ring or an alicyclic ring. The tensile strength is 40 N / mm ² or more when the resin molding is used alone, the tensile elongation is 3% or more and 10% or less, and the acrylate B is used as the resin molding alone. tensile strength is at 5N / mm ² or more 35N / mm ² or less, a tensile elongation of 30% or more, wherein the ratio of the two acrylate a and acrylate B is 10:90 to 90:10 It was invented to form a photocurable resin molding using the coating liquid. For example, the coating liquid is applied to a support such as a film or metal body with a thickness of 15 μm or more and 50 μm or less, and cured and peeled to obtain a photocurable resin molded body. Since the obtained photocurable resin molding has good tensile characteristics, the photocurable resin molding alone can be mounted on a liquid crystal display device as a thin, lightweight hard coat film, and liquid crystal with good visibility. Can provide a display.

  Moreover, it is preferable that the tensile elongation defined by the formula (I) mentioned later is 10% or more as for the photocurable resin laminated body which concerns on this invention.

  Moreover, it is preferable that the absolute value of thickness direction phase difference Rth defined by Formula (II) mentioned later is 2 or less as for the photocurable resin laminated body which concerns on this invention.

In the present invention, the resin to be applied consists of two types of acrylates A and B containing 2 or 3 acryloyl groups and / or methacryloyl groups, and the acrylate A has a urethane skeleton and an aromatic or alicyclic structure. In addition, the photocurable resin molding formed with acrylate A alone has a tensile strength of 40 N / mm ² or more, a tensile elongation of 3% or more and 10% or less, and a photocurable resin molding formed with acrylate B alone. tensile strength of the body is at 5N / mm ² or more 35N / mm ² or less, a tensile elongation of 30% or more, when the ratio of the two acrylate a and acrylate B is 10:90 to 90:10 The balance of the tensile strength and tensile elongation of the resin molded body (film) is improved.

  The ultraviolet curable resin (ultraviolet 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.

  As the ultraviolet curable resin used in the present invention, an acrylate (methacrylate) monomer can be used. Examples of urethane (meth) acrylate monomers having 2 or 3 acryloyl and / or methacryloyl groups and an aromatic or alicyclic structure include AT-600 (Kyoeisha Chemical), UA-306I (Kyoeisha Chemical), AH. -600 (Kyoeisha Chemical) etc. can be used. Examples of urethane (meth) acrylate monomers having 2 or 3 acryloyl groups or methacryloyl groups include epoxy ester 3002A (Kyoeisha Chemical), purple light UV-3520 (Japan Synthetic Chemical Industry), purple light UV-7000B ( Nippon Synthetic Chemical Industry), UF-8001G (Kyoeisha Chemical) and the like can be used.

  When a urethane (meth) acrylate monomer having an aromatic ring or alicyclic structure is used, relatively high strength characteristics can be obtained.

  In the present invention, it does not matter whether or not a solvent is added to the coating liquid, but any solvent that dissolves the photocurable resin can be used. In order to improve the surface properties after the coating film is formed, a solvent having a relatively high boiling point improves leveling properties (uniform coating properties). Further, when the coating film is thick, the solvent tends to remain in the coating film. Therefore, the boiling point should be as low as possible, and the solvent can be determined in consideration of the balance between the former and the latter.

  In addition, the ultraviolet polymerization initiator used in the coating liquid in the present invention is not particularly limited, but Irgacure 184 with particularly little coloration can be suitably used by curing the transparent resin. Further, surface-curing polymerization initiator α-hydroxy ketone, such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -Phenyl] -2-hydroxy-2-methyl-1-propan-1-one, an α-aminoketone 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1 having a high molar extinction coefficient -Acylphosphine oxide which is an internal curing polymerization initiator, for example, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and α-aminoketone having an absorption region in h-line, For example, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 is appropriately combined. It may be used Te Align.

  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 UV polymerization initiator used is preferably 0.5 to 15% by weight based on the total solid content of the UV curable resin (photosensitive coloring composition). Tend to be lower. 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, the material of the support is particularly limited as long as the resin molded body cured after UV curing can be easily peeled without deformation of the support in steps such as drying and UV curing. Is not to be done.

  Additives may be added to paints prepared by dissolving an ultraviolet curable resin, an ultraviolet polymerization initiator, and the like in a solvent in order to impart antifouling properties, slipperiness, prevent defects, and improve particle dispersibility. 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 the coating method of the said coating material to the support body. Specifically, bar coating, dip coating, spin coating, flow coating, spray coating, roll coating, gravure roll coating, air doctor coating, blade coating, wire doctor coating, knife coating Methods, reverse coating method, transfer roll coating method, micro gravure coating method, kiss coating method, cast coating method, slot orifice coating method, calendar coating method, die coating method and the like can be used.

The light source for curing the ultraviolet curable 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 can be set to 100 to 800 mJ / cm ² .

  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 photo-curable resin molded product (photo-curable resin film) obtained in the present invention has antireflection performance, antistatic performance, antifouling performance, antiglare performance, electromagnetic wave shielding performance, infrared absorption performance, ultraviolet rays as necessary. A functional layer having absorption performance, color correction performance, or the like 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.

  By providing the photocurable resin molded body described above on the polarizer sheet, a polarizing plate having a small phase difference and improved mechanical characteristics can be realized.

  In addition, in a transmissive liquid crystal display including an image display panel and a backlight unit, the image display panel is equipped with a polarizing plate including the photocurable resin molding according to the present invention, so that the phase difference is small and visibility is improved. Expected to be effective.

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

  The performance of the photocurable resin film (photocurable resin molding) was evaluated according to the following method.

Regarding the retardation Rth in the thickness direction of the photocurable resin film, a method of using a spectroscopic ellipsometer M220 (manufactured by JASCO Corporation) as a base material (substrate) on which a photocurable resin layer (coating film) is formed. The retardation Δ (λ) was measured from a direction inclined by 45 ° from the line direction, and Rth was calculated from the three-dimensional refractive index obtained by using this value, using Equation (3). The measurement wavelength of the spectroscopic ellipsometer was 590 nm.
Rth = {(Nx + Ny) / 2−Nz} × d (3)
Here, Nx is the refractive index in the slow axis direction in the plane of the photocurable resin layer, Ny is the refractive index in the fast axis direction (where Nx ≧ Ny), Nz is the refractive index in the thickness direction, and d is the light. It is the thickness of the curable resin molding.

The tensile property test was performed by forming a strip-shaped film sample of 100 mm × 15 mm from a photocurable resin film, using a small desktop tester EZ-L manufactured by Shimadzu Corporation, and setting the distance between chucks at the start of measurement to 50 mm, The test was performed at a speed of 5 mm / min. Moreover, 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)

  In forming the resin molding, urethanes 1 and 2 were synthesized with reference to Patent Document 3.

ここで、式中のＡは、アクリロイルオキシ基である。 [Production of Urethane 1]
In a reaction vessel equipped with a condenser, a stirrer and a thermometer, 31.5 parts by weight of isophorone diisocyanate and 0.1 part by weight of dibutyltin dilaurate were charged, and ε-caprolactone 1 mol-modified 2-hydroxyethyl acrylate at 50 ° C. After 4 parts by mass of the solution was added dropwise over 1 hour, the reaction was carried out 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, 99.9 parts by mass of “urethane 1” was obtained.

Here, A in the formula is an acryloyloxy group.

ここで、式中のＡは、アクリロイルオキシ基である。 [Production of Urethane 2]
A reaction vessel equipped with a condenser, a stirrer and a thermometer was charged with 23.1 parts by weight of isophorone diisocyanate and 0.1 parts by weight of dibutyltin dilaurate, and at 50 ° C., 2 mol of ε-caprolactone was modified with 2-hydroxyethyl acrylate 76. After 8 parts by weight were added dropwise over 1 hour, the reaction was carried out 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 2) 99.9 parts by weight were obtained.

Here, A in the formula is an acryloyloxy group.

<Example 1>
Urethane 1 38.1 parts by weight Epoxy ester 3002A (Kyoeisha Chemical Co., Ltd.) 38.1 parts by weight Irgacure 184 (BASF) 3.8 parts by weight Methyl ethyl ketone 20.0 parts by weight The film (Lumirror T-60-75 μm: Toray) is applied and dried by a bar coating method to a cured film thickness of 15 μm, and irradiated with 400 mJ / cm ² of UV light with a metal halide lamp, and the photocured coating film is peeled off. As a result, a photocurable resin-formed body was obtained. This photocurable resin molded body (film) had a tensile strength of 40 N / mm ² , a tensile elongation of 20%, and a phase difference Rth of 0.5. A film having good tensile properties and a small retardation could be formed.

<Example 2>
Urethane 1 38.1 parts by weight Purple light UV-7000B (Nippon Synthetic Chemical Industry) 38.1 parts by weight Irgacure 184 (BASF) 3.8 parts by weight Methyl ethyl ketone 20.0 parts by weight The above composition was stirred and mixed. Is applied to a PET film (Lumirror T60-75 μm: Toray) by a bar coating method to a cured film thickness of 35 μm, dried, and irradiated with 400 mJ / cm ² of ultraviolet rays with a metal halide lamp to form a photocured coating film. It peeled and the photocurable resin formation body was obtained. The photocurable resin molded body (film) had a tensile strength of 60 N / mm ² , a tensile elongation of 20%, and a phase difference Rth of 1. A film having good tensile properties and a small retardation could be formed.

<Example 3>
Urethane 1 38.1 parts by weight UF-8001 G (Kyoeisha Chemical) 38.1 parts by weight Irgacure 184 (BASF) 3.8 parts by weight methyl ethyl ketone 20.0 parts by weight The film (Lumirror T60-75 μm: Toray) was applied and dried by a bar coating method to a cured film thickness of 45 μm, irradiated with 400 mJ / cm ² of ultraviolet rays with a metal halide lamp, and the photocured coating film was peeled off. A photocurable resin formed body was obtained. The photocurable resin molded body (film) had a tensile strength of 45 N / mm ² , a tensile elongation of 60%, and a phase difference Rth of 1. A film having good tensile properties and a small retardation could be formed.

<Example 4>
Urethane 2 38.1 parts by weight UV-3520 (Nippon Synthetic Chemical Industry) 38.1 parts by weight Irgacure 184 (BASF) 3.8 parts by weight methyl ethyl ketone 20.0 parts by weight The coating solution obtained by stirring and mixing the above composition , PET film (Lumirror T-60-75 μm: Toray) was coated and dried to a cured film thickness of 40 μm by the bar coating method, and irradiated with 400 mJ / cm ² of ultraviolet light with a metal halide lamp, and photocured. Was peeled off to obtain a photocurable resin formed body. The photocurable resin molded body (film) had a tensile strength of 45 N / mm ² , a tensile elongation of 55%, and a phase difference Rth of 1. A film having good tensile properties and a small retardation could be formed.

<Example 5>
Urethane 2 22.9 parts by weight Purple light UV-7000B (Nippon Synthetic Chemical Industry) 53.3 parts by weight Irgacure 184 (BASF) 3.8 parts by weight Methyl ethyl ketone 20.0 parts by weight The above composition was stirred and mixed. The PET film (Lumirror T60-75 μm: Toray) was coated and dried by a bar coating method to a cured film thickness of 40 μm, and irradiated with 400 mJ / cm ² of ultraviolet light with a metal halide lamp to form a photocured coating film. It peeled and the photocurable resin formation body was obtained. The photocurable resin molded body (film) had a tensile strength of 45 N / mm ² , a tensile elongation of 25%, and a phase difference Rth of 1. A film having good tensile properties and a small retardation could be formed.

<Example 6>
Urethane 2 38.1 parts by weight Purple light UV-7000B (Nippon Synthetic Chemical Industry) 38.1 parts by weight Irgacure 184 (BASF) 3.8 parts by weight methyl ethyl ketone 20.0 parts by weight The above composition was stirred and mixed. The PET film (Lumirror T60-75 μm: Toray) was coated and dried by a bar coating method to a cured film thickness of 40 μm, and irradiated with 400 mJ / cm ² of ultraviolet light with a metal halide lamp to form a photocured coating film. It peeled and the photocurable resin formation body was obtained. The photocurable resin molded body (film) had a tensile strength of 50 N / mm ² , a tensile elongation of 20%, and a phase difference Rth of 1. A film having good tensile properties and a small retardation could be formed.

<Example 7>
Urethane 2 68.6 parts by weight Purple light UV-7000B (Nippon Synthetic Chemical Industry) 7.6 parts by weight Irgacure 184 (BASF) 3.8 parts by weight methyl ethyl ketone 20.0 parts by weight The above composition was stirred and mixed. The PET film (Lumirror T60-75 μm: Toray) was coated and dried by a bar coating method to a cured film thickness of 40 μm, and irradiated with 400 mJ / cm ² of ultraviolet light with a metal halide lamp to form a photocured coating film. It peeled and the photocurable resin formation body was obtained. The photocurable resin molded body (film) had a tensile strength of 65 N / mm ² , a tensile elongation of 10%, and a retardation Rth of 1. A film having good tensile properties and a small retardation could be formed.

<Example 8>
Urethane 2 53.3 parts by weight Epoxy ester 3002A (Kyoeisha Chemical) 22.9 parts by weight Irgacure 184 (BASF) 3.8 parts by weight methyl ethyl ketone 20.0 parts by weight The film (Lumirror T60-75 μm: Toray) was coated and dried by a bar coating method to a cured film thickness of 40 μm, irradiated with 400 mJ / cm ² of ultraviolet light with a metal halide lamp, and the photocured coating film was peeled off. A photocurable resin formed body was obtained. The photocurable resin molded body (film) had a tensile strength of 55 N / mm ² , a tensile elongation of 15%, and a phase difference Rth of 0.5. A film having good tensile properties and a small retardation could be formed.

<Example 9>
AT-600 (Kyoeisha Chemical) 38.1 parts by weight Epoxy ester 3002A (Kyoeisha Chemical) 38.1 parts by weight Irgacure 184 (BASF) 3.8 parts by weight Methyl ethyl ketone 20.0 parts by weight The above composition was stirred and mixed. The coating solution was applied and dried on a PET film (Lumirror T60-75 μm: Toray) by a bar coating method so as to have a cured film thickness of 50 μm, and irradiated with 400 mJ / cm ² of ultraviolet light with a metal halide lamp, and then photocured. The film was peeled off to obtain a photocurable resin formed body. The photocurable resin molded body (film) had a tensile strength of 65 N / mm ² , a tensile elongation of 20%, and a phase difference Rth of 2. A film having good tensile properties and a small retardation could be formed.

<Comparative Example 1>
UA306I (Kyoeisha Chemical Co., Ltd.) 38.1 parts by weight Purple light UV-7000B (Nippon Synthetic Chemical Industry) 38.1 parts by weight Irgacure 184 (BASF) 3.8 parts by weight methyl ethyl ketone 20.0 parts by weight The above composition is stirred and mixed The applied coating solution was applied and dried on a PET film (Lumirror T60-75 μm: Toray) by a bar coating method so as to have a cured film thickness of 40 μm, and irradiated with 400 mJ / cm ² of ultraviolet rays with a metal halide lamp, and photocured. The coating film was peeled off to obtain a photocurable resin formed body. The photocurable resin molded body (film) had a tensile strength of 70 N / mm ² , a tensile elongation of 15%, and a retardation Rth of 10. Because of the large number of functional groups, a film having high strength and large retardation was formed.

<Comparative Example 2>
Urethane 1 3.8 parts by weight UF-8001G (Kyoeisha Chemical Co., Ltd.) 72.4 parts by weight Irgacure 184 (BASF) 3.8 parts by weight methyl ethyl ketone 20.0 parts by weight The film (Lumirror T60-75 μm: Toray) was coated and dried by a bar coating method to a cured film thickness of 40 μm, irradiated with 400 mJ / cm ² of ultraviolet light with a metal halide lamp, and the photocured coating film was peeled off. A photocurable resin formed body was obtained. This photocurable resin molded body (film) had a tensile strength of 8 N / mm ² , a tensile elongation of 110%, and a phase difference Rth of 0.5. Since the resin ratio of urethane 1 was low, a film having a small strength and a small phase difference was formed.

<Comparative Example 3>
Urethane 1 22.9 parts by weight UF-8001G (Kyoeisha Chemical Co., Ltd.) 53.3 parts by weight Irgacure 184 (BASF) 3.8 parts by weight methyl ethyl ketone 20.0 parts by weight The film (Lumirror T60-75 μm: Toray) was applied and dried by a bar coating method so as to have a cured film thickness of 60 μm, irradiated with 400 mJ / cm ² of ultraviolet rays with a metal halide lamp, and the photocured coating film was peeled off. A photocurable resin formed body was obtained. The photocurable resin molded body (film) had a tensile strength of 30 N / mm ² , a tensile elongation of 85%, and a retardation Rth of 1. Since the film thickness is thick, curing near the support is weakened at the time of curing, so that a film having a small strength and a small phase difference is formed.

<Comparative example 4>
AH-600 (Kyoeisha Chemical Co., Ltd.) 38.1 parts by weight Purple light UV-7000B (Nippon Synthetic Chemical Industry) 38.1 parts by weight Irgacure 184 (BASF) 3.8 parts by weight Methyl ethyl ketone 20.0 parts by weight The above composition is stirred. The mixed coating solution is applied and dried on a PET film (Lumirror T60-75 μm: Toray) by a bar coating method so as to have a cured film thickness of 40 μm, and irradiated with 400 mJ / cm ² ultraviolet rays by a metal halide lamp. The cured coating film was peeled off to obtain a photocurable resin formed body. The photocurable resin molded body (film) had a tensile strength of 35 N / mm ² , a tensile elongation of 15%, and a retardation Rth of 1. Since a resin having no aromatic ring or ring structure is used, a film having a small strength and a small retardation is formed.

  The evaluation results of Examples 1 to 9 and Comparative Examples 1 to 4 are summarized in Table 1.

  The photocurable resin molded product (photocurable resin film) of the present invention is a thin film because it does not contain a substrate such as a PET film, and there is no need to consider the retardation of the substrate itself such as a PET film. Therefore, it can be used as an optical film with low retardation. Therefore, a visibility improvement effect is expected in a liquid crystal display equipped with this photocurable resin molded body. Since the tensile properties are good, the workability in the manufacturing process can be expected to improve.

  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 can utilize for a photocurable resin coating film etc.

Claims (4)

A photocurable resin molding obtained by photocuring a photopolymerizable composition,
The photopolymerizable composition contains a photocurable resin and an ultraviolet polymerization initiator,
The photocurable resin is composed of two types of acrylates A and B having 2 or 3 (meth) acryloyl groups,
The acrylate A has a urethane skeleton and an aromatic ring or alicyclic structure, and has a tensile strength of 40 N / mm ² or more when used alone as a resin molded body, and is defined by the following formula (I) The degree is 3% or more and 10% or less,
The acrylate B is a singly in tensile strength when formed into a resin molded product 5N / mm ² or more 35N / mm ² or less, a tensile elongation of 30% or more,
The weight ratio of the acrylate A and the acrylate B is 90:10 to 10:90,
Thickness Ri der least 50μm or less 15 [mu] m,
The tensile strength of the photocurable resin molded body is 40 N / mm ² or more,
The tensile elongation is Ru der least 10%, the photocurable resin molded article of the photocurable resin molded body.
Tensile elongation (%) = {(length at break) − (initial length before tension)} × 100 / initial length before tension
... Formula (I) The photocurable resin molded article according to claim 1, wherein a retardation Rth in the thickness direction represented by the following formula (II) of the photocurable resin molded article is 2 nm or less.
Rth = {(Nx + Ny) / 2−Nz} × d Formula (II)
Here, Nx is the refractive index in the slow axis direction in the plane of the photocurable resin layer, Ny is the refractive index in the fast axis direction (where Nx ≧ Ny), Nz is the refractive index in the thickness direction, and d is the light. It is the thickness of the curable resin molding.   A polarizing plate comprising the photocurable resin molded product according to claim 1.   A transmissive liquid crystal display comprising the photocurable resin molded product according to claim 1.