JP2015090467A - Optical laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical laminate which satisfies requirements on adhesion between a hard coat layer and a base material layer and hardness and which can be manufactured without heating to such a temperature that may cause deformation of the base material film.SOLUTION: The optical laminate of the present invention comprises; a base material layer comprising a (meth)acrylic resin film; a hard coat layer formed by coating the (meth)acrylic resin film with a hard coat layer-forming composition; and a permeated layer formed between the base material layer and hard coat layer by permeating the hard coat layer-forming composition into the (meth)acrylic resin film. The hard coat layer-forming composition contains; a curable compound (A) containing one or more radically polymerizable unsaturated groups and an aromatic ring; a curable compound (B) containing two or more radically polymerizable unsaturated groups but not containing an aromatic ring; and a mono-functional monomer (C) containing one radially polymerizable unsaturated group but not containing an aromatic ring.

Description

  The present invention relates to an optical laminate.

  Image display devices such as liquid crystal display (LCD), cathode ray tube display device (CRT), plasma display (PDP), electroluminescence display (ELD), etc. are visible when the surface is damaged by external contact. May decrease. For this reason, an optical laminate including a base film and a hard coat layer is used for the purpose of protecting the surface of the image display device. As a base film of the optical laminate, triacetyl cellulose (TAC) is typically used (Patent Document 1). However, the base film made of TAC has high moisture permeability. Therefore, when an optical laminate including such a substrate film is used in an LCD, moisture is transmitted through the optical laminate under high temperature and high humidity, resulting in a problem that the optical characteristics of the polarizer are deteriorated. In recent years, in addition to indoor use, LCDs are also frequently used for outdoor use devices such as car navigation systems and personal digital assistants. Even under severe conditions such as high temperature and high humidity, There is a need for a reliable LCD that does not cause problems.

  In order to solve the above problem, the hard coat layer-forming composition is allowed to penetrate into the base film by applying and heating the hard coat layer-forming composition on the low moisture-permeable acrylic base film. Optical laminated bodies with improved adhesion between the base film and the hard coat layer have been proposed (for example, Patent Document 2 and Patent Document 3). However, in the production of the optical laminate of Patent Document 2, since it is necessary to heat at a temperature close to the Tg of the base film in order to obtain sufficient adhesion, the base film may be deformed (for example, contracted). There is. On the other hand, in the production of the optical laminate of Patent Document 3, the adhesiveness can be improved by infiltrating the base film with the composition for forming a hard coat layer by heating at a relatively low temperature, but the hardness is insufficient. There is a case.

JP 2008-165205 A JP 2012-234163 A JP 2013-50641 A

  The present invention provides an optical laminate that can achieve both the adhesion and hardness of the hard coat layer and the base material layer, and can be produced without requiring heating at a temperature that can cause deformation of the base material film. provide.

The optical layered body of the present invention includes a base layer formed from a (meth) acrylic resin film, and a hard coat formed by coating the (meth) acrylic resin film with a composition for forming a hard coat layer And a permeation layer formed by permeating the (meth) acrylic resin film between the layer and the base material layer and the hard coat layer. The hard coat layer-forming composition contains a curable compound (A) containing one or more radically polymerizable unsaturated groups and an aromatic ring, and two or more radically polymerizable unsaturated groups. A curable compound (B) that does not contain a ring and a monofunctional monomer (C) that contains one radical polymerizable unsaturated group but does not contain an aromatic ring.
In one embodiment, the content rate of the sclerosing | hardenable compound (A) with respect to all the sclerosing | hardenable compounds in the said composition for hard-coat layer formation is 10 weight%-60 weight%.
In one embodiment, the total content of the curable compound (A) and the monofunctional monomer (C) with respect to the total curable compound in the hard coat layer forming composition is 20% by weight to 70% by weight. .
In one embodiment, the said composition for hard-coat layer formation contains the sclerosing | hardenable compound (B1) containing a 9 or more radically polymerizable unsaturated group as a sclerosing | hardenable compound (B).
In one embodiment, the weight average molecular weight of the said monofunctional monomer (C) is 500 or less.
In one embodiment, the monofunctional monomer (C) has a hydroxyl group.
In one embodiment, the (meth) acrylic resin forming the (meth) acrylic resin film has a structural unit that exhibits positive birefringence and a structural unit that exhibits negative birefringence.
In one embodiment, the weight average molecular weight of the (meth) acrylic resin that forms the (meth) acrylic resin film is 10,000 to 500,000.
In one embodiment, the surface of the hard coat layer opposite to the osmotic layer has a concavo-convex structure.
In one embodiment, an antireflection layer is further provided on the opposite side of the hard coat layer from the permeation layer.
According to another aspect of the present invention, a polarizing film is provided. This polarizing film contains the said optical laminated body.
According to still another aspect of the present invention, an image display device is provided. The image display device includes the optical laminate.
According to another situation of this invention, the manufacturing method of an optical laminated body is provided. The production method includes applying a hard coat layer forming composition on a (meth) acrylic resin film to form a coating layer, and heating the coating layer at 50 ° C. or more and less than 100 ° C. The hard coat layer-forming composition contains a curable compound (A) containing one or more radically polymerizable unsaturated groups and an aromatic ring, and two or more radically polymerizable unsaturated groups. A curable compound (B) that does not contain a ring and a monofunctional monomer (C) that contains one radical polymerizable unsaturated group but does not contain an aromatic ring.

  According to the present invention, by using a composition for forming a hard coat layer containing predetermined three kinds of curable compounds, both the adhesion and hardness between the base layer and the hard coat layer are excellent, and the base material An optical laminate is obtained that can be manufactured without the need for heating at a temperature that can cause deformation of the film.

(A) is a schematic sectional drawing of the optical laminated body by preferable embodiment of this invention, (b) is an example of the schematic sectional drawing of the optical laminated body which does not have a osmosis | permeation layer. It is a schematic sectional drawing of the optical laminated body by another embodiment of this invention.

Hereinafter, although preferable embodiment of this invention is described, this invention is not limited to these embodiment.
A. 1A is a schematic cross-sectional view of an optical laminate according to a preferred embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view of an optical laminate having no osmotic layer. It is. The optical laminated body 100 shown to Fig.1 (a) is equipped with the base material layer 10 formed from a (meth) acrylic-type resin film, the osmosis | permeation layer 20, and the hard-coat layer 30 in this order. The hard coat layer 30 is formed by applying a composition for forming a hard coat layer to a (meth) acrylic resin film. The permeation layer 20 is formed by permeating the (meth) acrylic resin film with the hard coat layer forming composition. When the composition for forming a hard coat layer penetrates into the (meth) acrylic resin film in this way, the composition for forming the hard coat layer reaches (penetrates) in the (meth) acrylic resin film. This is the part that did not. On the other hand, in the optical laminated body 200 shown in FIG. Boundary A shown in FIGS. 1A and 1B is a boundary defined by the hard coat layer forming composition coating surface of the (meth) acrylic resin film. Therefore, the boundary A is the boundary between the osmotic layer 20 and the hard coat layer 30 in the optical laminate 100, and the base layer 10 ′ (ie, (meta)) in the optical laminate 200 in which the osmotic layer is not formed. This is the boundary between the acrylic resin film) and the hard coat layer 30 '. In the present specification, “(meth) acryl” means acryl and / or methacryl.

  As described above, the penetration layer 20 is formed by penetrating the (meth) acrylic resin film in the optical laminate 100 with the hard coat layer forming composition. That is, the osmotic layer 20 is a portion where a hard coat layer component is present in the (meth) acrylic resin film. The thickness of the osmotic layer 20 is, for example, 1.0 μm or more. In addition, the thickness of the osmosis | permeation layer 20 is the thickness of the part in which the hard-coat layer component exists in the said (meth) acrylic-type resin film, Specifically, a hard-coat layer in a (meth) acrylic-type resin film. The distance between the boundary A and the boundary A between the portion where the component is present (penetrating layer) and the portion where the component is not present (base material layer).

  In the optical layered body of the present invention, any appropriate other layer (not shown) may be disposed outside the hard coat layer 30 as necessary. The other layers are typically disposed via an adhesive layer (not shown).

  The (meth) acrylic resin forming the (meth) acrylic resin film may be eluted in the hard coat layer forming composition, and the (meth) acrylic resin may be present in the hard coat layer. .

  FIG. 2 is a schematic cross-sectional view of an optical laminate according to another embodiment of the present invention. The optical layered body 300 further includes a block layer 40 on the opposite side of the hard coat layer 30 from the osmotic layer 20. In the block layer 40, the (meth) acrylic resin forming the (meth) acrylic resin film elutes in the hardcoat layer forming composition, and the hardcoat layer forming composition is the (meth) acrylic resin. And by causing phase separation. The optical laminate including the block layer 40 is excellent in hardness.

  The amplitude of the reflection spectrum of the hard coat layer in the wavelength range of 500 nm to 600 nm of the optical layered body of the present invention is preferably 0.5% or less, more preferably 0.3% or less, and still more preferably 0.8. 1% or less. According to the present invention, it is possible to obtain an optical laminated body having a small reflection spectrum amplitude, that is, having little interference unevenness.

  The pencil hardness of the hard coat layer surface of the optical layered body of the present invention is preferably 2H or higher, more preferably 3H or higher.

  The optical layered body of the present invention is applied to, for example, a polarizing film (also referred to as a polarizing plate). Specifically, the optical laminate of the present invention is provided on one or both sides of a polarizer in a polarizing film, and can be suitably used as a protective material for the polarizer.

B. Base material layer The base material layer is formed of a (meth) acrylic resin film. More specifically, as described above, when the base layer is coated with the composition for forming a hard coat layer on the (meth) acrylic resin film, in the (meth) acrylic resin film, This is the part where the forming composition did not reach (penetrate).

  The (meth) acrylic resin film includes a (meth) acrylic resin. The (meth) acrylic resin film is obtained, for example, by extruding a molding material containing a resin component containing a (meth) acrylic resin as a main component.

The moisture permeability of the (meth) acrylic resin film is preferably 200 g / m ² · 24 hr or less, and more preferably 80 g / m ² · 24 hr or less. According to the present invention, even when a (meth) acrylic resin film having such a high moisture permeability is used, the adhesion between the (meth) acrylic resin film and the hard coat layer is excellent, and interference unevenness is suppressed. An optical laminate can be obtained. The moisture permeability can be measured under the test conditions of 40 ° C. and a relative humidity of 92%, for example, by a method according to JIS Z 0208.

  The light transmittance at a wavelength of 380 nm of the (meth) acrylic resin film is preferably 15% or less, more preferably 12% or less, and further preferably 9% or less. If the transmittance of light having a wavelength of 380 nm is in such a range, an excellent ultraviolet absorbing ability is exhibited, so that deterioration of ultraviolet rays due to external light or the like of the optical laminate can be prevented.

The in-plane retardation Re of the (meth) acrylic resin film is preferably 10 nm or less, more preferably 7 nm or less, still more preferably 5 nm or less, particularly preferably 3 nm or less, and most preferably 1 nm or less. The thickness direction retardation Rth of the (meth) acrylic resin film is preferably 15 nm or less, more preferably 10 nm or less, further preferably 5 nm or less, particularly preferably 3 nm or less, and most preferably 1 nm. It is as follows. If the in-plane retardation and the thickness direction retardation are within such ranges, the adverse effect on the display characteristics of the image display apparatus due to the phase difference can be remarkably suppressed. More specifically, interference unevenness and 3D image distortion when used in a liquid crystal display device for 3D display can be significantly suppressed. A (meth) acrylic resin film having in-plane retardation and thickness direction retardation in such a range can be obtained by using, for example, a (meth) acrylic resin having a glutarimide structure described later. The in-plane retardation Re and the thickness direction retardation Rth can be obtained by the following equations, respectively:
Re = (nx−ny) × d
Rth = (nx−nz) × d
Here, nx is the refractive index in the slow axis direction of the (meth) acrylic resin film, ny is the refractive index in the fast axis direction of the (meth) acrylic resin film, and nz is the (meth) acrylic system. It is the refractive index in the thickness direction of the resin film, and d (nm) is the thickness of the (meth) acrylic resin film. The slow axis refers to the direction in which the in-plane refractive index is maximized, and the fast axis refers to the direction perpendicular to the slow axis in the plane. Typically, Re and Rth are measured using light having a wavelength of 590 nm.

Any appropriate (meth) acrylic resin can be adopted as the (meth) acrylic resin. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester -(Meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer) And methyl methacrylate- (meth) acrylate norbornyl copolymer). Preferably, poly (meth) acrylic acid C _1-6 alkyl such as poly (meth) acrylate methyl is used. More preferably, a methyl methacrylate resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

  The weight average molecular weight of the (meth) acrylic resin is preferably 10,000 to 500,000, more preferably 30,000 to 300,000, and still more preferably 50,000 to 200,000. If a weight average molecular weight is in the said range, it is excellent in compatibility with the composition for hard-coat layer formation. On the other hand, if the weight average molecular weight is too small, the mechanical strength of the film tends to be insufficient. When the weight average molecular weight is too large, the viscosity at the time of melt extrusion is high, the molding processability is lowered, and the productivity of the molded product tends to be lowered.

  The glass transition temperature of the (meth) acrylic resin is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. When the glass transition temperature is in such a range, a (meth) acrylic resin film excellent in durability and heat resistance can be obtained. The upper limit of the glass transition temperature is not particularly limited, but is preferably 170 ° C. or less from the viewpoint of moldability and the like.

  The (meth) acrylic resin preferably has a structural unit that exhibits positive birefringence and a structural unit that exhibits negative birefringence. If these structural units are included, the abundance ratio can be adjusted to control the retardation of the (meth) acrylic resin film, and a (meth) acrylic resin film having a low retardation can be obtained. it can. Examples of the structural unit exhibiting positive birefringence include a structural unit constituting a lactone ring, polycarbonate, polyvinyl alcohol, cellulose acetate, polyester, polyarylate, polyimide, polyolefin, etc., and a general formula (1) described later. Examples include structural units. Examples of the structural unit exhibiting negative birefringence include a structural unit derived from a styrene monomer, a maleimide monomer, a structural unit of polymethyl methacrylate, a structural unit represented by the general formula (3) described later, and the like. Can be mentioned. In the present specification, a structural unit that exhibits positive birefringence is a case where a resin having only the structural unit exhibits positive birefringence characteristics (that is, a slow axis appears in the stretching direction of the resin). Means a structural unit. In addition, a structural unit that develops negative birefringence is when a resin having only the structural unit exhibits negative birefringence characteristics (that is, when a slow axis appears in a direction perpendicular to the stretching direction of the resin). Means a structural unit of

  As the (meth) acrylic resin, a (meth) acrylic resin having a lactone ring structure or a glutarimide structure is preferably used. A (meth) acrylic resin having a lactone ring structure or a glutarimide structure is excellent in heat resistance. More preferred is a (meth) acrylic resin having a glutarimide structure. If a (meth) acrylic resin having a glutarimide structure is used, a (meth) acrylic resin film having low moisture permeability and a small retardation and ultraviolet transmittance can be obtained as described above. Examples of (meth) acrylic resins having a glutarimide structure (hereinafter also referred to as glutarimide resins) include, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, and JP-A-2006-328329. 2006-328334, JP-A 2006-337491, JP-A 2006-337492, JP-A 2006-337493, JP-A 2006-337469, JP-A 2007-009182, JP-A 2009- No. 161744. These descriptions are incorporated herein by reference.

Preferably, the glutarimide resin includes a structural unit represented by the following general formula (1) (hereinafter also referred to as a glutarimide unit) and a structural unit represented by the following general formula (2) (hereinafter referred to as (meta)). Also referred to as an acrylate unit).
In Formula (1), R ¹ and R ² are each independently hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ is hydrogen, an alkyl group having 1 to 18 carbon atoms, or 3 to 3 carbon atoms. It is a substituent containing 12 cycloalkyl groups or an aromatic ring having 5 to 15 carbon atoms. In Formula (2), R ⁴ and R ⁵ are each independently hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ is hydrogen, an alkyl group having 1 to 18 carbon atoms, or 3 to 3 carbon atoms. It is a substituent containing 12 cycloalkyl groups or an aromatic ring having 5 to 15 carbon atoms.

The glutarimide resin may further contain a structural unit represented by the following general formula (3) (hereinafter also referred to as an aromatic vinyl unit) as necessary.
In Formula (3), R ⁷ is hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁸ is an aryl group having 6 to 10 carbon atoms.

In the general formula (1), preferably, R ¹ and R ² are each independently hydrogen or a methyl group, R ³ is hydrogen, a methyl group, a butyl group, or a cyclohexyl group, and more preferably , R ¹ is a methyl group, R ² is hydrogen, and R ³ is a methyl group.

The glutarimide resin may include only a single type as a glutarimide unit, or may include a plurality of types in which R ¹ , R ² , and R ³ in the general formula (1) are different. Good.

  The glutarimide unit can be formed by imidizing the (meth) acrylic acid ester unit represented by the general formula (2). The glutarimide unit is an acid anhydride such as maleic anhydride, or a half ester of such an acid anhydride and a linear or branched alcohol having 1 to 20 carbon atoms; acrylic acid, methacrylic acid, maleic acid. It can also be formed by imidizing an α, β-ethylenically unsaturated carboxylic acid such as maleic anhydride, itaconic acid, itaconic anhydride, crotonic acid, fumaric acid, citraconic acid and the like.

In the general formula (2), preferably, R ⁴ and R ⁵ are each independently hydrogen or a methyl group, R ⁶ is hydrogen or a methyl group, and more preferably, R ⁴ is hydrogen. , R ⁵ is a methyl group, and R ⁶ is a methyl group.

The glutarimide resin may contain only a single type as a (meth) acrylic acid ester unit, or a plurality of types in which R ⁴ , R ⁵ and R ⁶ in the general formula (2) are different. May be included.

  The glutarimide resin preferably contains styrene, α-methylstyrene, and more preferably styrene as the aromatic vinyl unit represented by the general formula (3). By having such an aromatic vinyl unit, the positive birefringence of the glutarimide structure can be reduced, and a (meth) acrylic resin film having a lower retardation can be obtained.

The glutarimide resin may contain only a single type as an aromatic vinyl unit, or may contain a plurality of types in which R ⁷ and R ⁸ are different.

The content of the glutarimide unit in the glutarimide resin is preferably changed depending on, for example, the structure of R ³ . The content of the glutarimide unit is preferably 1% by weight to 80% by weight, more preferably 1% by weight to 70% by weight, even more preferably 1% by weight, based on the total structural unit of the glutarimide resin. -60% by weight, particularly preferably 1-50% by weight. When the content of the glutarimide unit is in such a range, a (meth) acrylic resin film having a low retardation excellent in heat resistance can be obtained.

  The content of the aromatic vinyl unit in the glutarimide resin can be appropriately set according to the purpose and desired characteristics. Depending on the application, the content of the aromatic vinyl unit may be zero. When the aromatic vinyl unit is contained, the content thereof is preferably 10% by weight to 80% by weight, more preferably 20% by weight to 80% by weight, based on the glutarimide unit of the glutarimide resin. More preferably, it is 20 to 60% by weight, and particularly preferably 20 to 50% by weight. When the content of the aromatic vinyl unit is within such a range, a (meth) acrylic resin film having a low retardation, excellent heat resistance and mechanical strength can be obtained.

  The glutarimide resin may further be copolymerized with other structural units other than the glutarimide unit, the (meth) acrylic acid ester unit, and the aromatic vinyl unit, if necessary. Other structural units include, for example, nitrile monomers such as acrylonitrile and methacrylonitrile, and structures composed of maleimide monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide. Units are listed. These other structural units may be directly copolymerized or graft copolymerized in the glutarimide resin.

  The (meth) acrylic resin film contains an ultraviolet absorber. As the ultraviolet absorber, any appropriate ultraviolet absorber can be adopted as long as the desired characteristics are obtained. Representative examples of the above UV absorbers include triazine UV absorbers, benzotriazole UV absorbers, benzophenone UV absorbers, cyanoacrylate UV absorbers, benzoxazine UV absorbers, and oxadiazole UV absorbers. Agents. These ultraviolet absorbers may be used alone or in combination.

  The content of the ultraviolet absorber is preferably 0.1 parts by weight to 5 parts by weight, more preferably 0.2 parts by weight to 3 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin. . When the content of the ultraviolet absorber is in such a range, ultraviolet rays can be absorbed effectively and the transparency of the film during film formation does not deteriorate. When the content of the ultraviolet absorber is less than 0.1 parts by weight, the ultraviolet blocking effect tends to be insufficient. When there is more content of a ultraviolet absorber than 5 weight part, there exists a tendency for coloring to become intense or the haze of the film after shaping | molding becomes high, and transparency deteriorates.

  The said (meth) acrylic-type resin film can contain arbitrary appropriate additives according to the objective. Examples of additives include hindered phenol-based, phosphorus-based and sulfur-based antioxidants; light-resistant stabilizers, weather-resistant stabilizers, heat stabilizers and other stabilizers; reinforcing materials such as glass fibers and carbon fibers; Infrared absorbers; flame retardants such as tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide; antistatic agents such as anionic, cationic and nonionic surfactants; coloring of inorganic pigments, organic pigments, dyes, etc. Agents; organic fillers and inorganic fillers; resin modifiers; plasticizers; lubricants; retardation reducing agents. The kind, combination, content, and the like of the additive to be contained can be appropriately set according to the purpose and desired characteristics.

  Although it does not specifically limit as a manufacturing method of the said (meth) acrylic-type resin film, For example, (meth) acrylic-type resin, an ultraviolet absorber, and other polymers, additives, etc. as needed Are sufficiently mixed by any appropriate mixing method to obtain a thermoplastic resin composition in advance, and then this can be formed into a film. Alternatively, a (meth) acrylic resin, an ultraviolet absorber, and if necessary, other polymers and additives are mixed in separate solutions to form a uniform mixed solution, and then film forming May be.

  In order to produce the thermoplastic resin composition, for example, the film raw material is pre-blended with any appropriate mixer such as an omni mixer, and then the obtained mixture is extrusion kneaded. In this case, the mixer used for extrusion kneading is not particularly limited, and for example, any suitable mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader may be used. Can do.

  Examples of the film forming method include any appropriate film forming method such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. A melt extrusion method is preferred. Since the melt extrusion method does not use a solvent, it is possible to reduce the manufacturing cost and the burden on the global environment and work environment due to the solvent.

  Examples of the melt extrusion method include a T-die method and an inflation method. The molding temperature is preferably 150 to 350 ° C, more preferably 200 to 300 ° C.

  When film-forming by the above T-die method, a T-die is attached to the tip of a known single-screw extruder or twin-screw extruder, and the film extruded into a film is wound to obtain a roll-shaped film Can do. At this time, it is possible to perform uniaxial stretching by appropriately adjusting the temperature of the winding roll and adding stretching in the extrusion direction. Also, simultaneous biaxial stretching, sequential biaxial stretching, and the like can be performed by stretching the film in a direction perpendicular to the extrusion direction.

  The (meth) acrylic resin film may be either an unstretched film or a stretched film as long as the desired retardation is obtained. In the case of a stretched film, either a uniaxially stretched film or a biaxially stretched film may be used. In the case of a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used.

  The stretching temperature is preferably in the vicinity of the glass transition temperature of the thermoplastic resin composition that is the film raw material, and specifically, preferably (glass transition temperature-30 ° C.) to (glass transition temperature + 30 ° C.) Preferably, it is within the range of (glass transition temperature−20 ° C.) to (glass transition temperature + 20 ° C.). If the stretching temperature is lower than (glass transition temperature −30 ° C.), the haze of the resulting film may increase, or the film may be torn or cracked, resulting in failure to obtain a predetermined stretching ratio. On the other hand, when the stretching temperature exceeds (glass transition temperature + 30 ° C.), the thickness unevenness of the resulting film becomes large, and the mechanical properties such as elongation, tear propagation strength, and fatigue resistance cannot be sufficiently improved. There is a tendency to. Furthermore, there is a tendency that troubles such as the film sticking to the roll tend to occur.

  The draw ratio is preferably 1.1 to 3 times, more preferably 1.3 to 2.5 times. When the draw ratio is in such a range, the mechanical properties such as the film elongation, tear propagation strength, and fatigue resistance can be greatly improved. As a result, it is possible to produce a film with small thickness unevenness, substantially zero birefringence (and therefore a small phase difference), and a small haze.

  The (meth) acrylic resin film can be subjected to heat treatment (annealing) or the like after the stretching treatment in order to stabilize its optical isotropy and mechanical properties. Arbitrary appropriate conditions can be employ | adopted for the conditions of heat processing.

  The thickness of the (meth) acrylic resin film is preferably 10 μm to 200 μm, more preferably 20 μm to 100 μm. There exists a possibility that intensity | strength may fall that thickness is less than 10 micrometers. If the thickness exceeds 200 μm, the transparency may decrease.

  The surface tension of the (meth) acrylic resin film is preferably 40 mN / m or more, more preferably 50 mN / m or more, and still more preferably 55 mN / m or more. When the surface wetting tension is at least 40 mN / m or more, the adhesion between the (meth) acrylic resin film and the hard coat layer is further improved. Any suitable surface treatment can be applied to adjust the surface wetting tension. Examples of the surface treatment include corona discharge treatment, plasma treatment, ozone spraying, ultraviolet irradiation, flame treatment, and chemical treatment. Of these, corona discharge treatment and plasma treatment are preferable.

C. Penetration layer The penetration layer is formed by the penetration of the composition for forming a hard coat layer into the (meth) acrylic resin film as described above. In other words, the osmotic layer can correspond to a part of the compatibilized region between the (meth) acrylic resin forming the (meth) acrylic resin film and the component forming the hard coat layer.

  In the permeation layer, it is preferable that the concentration of the (meth) acrylic resin forming the (meth) acrylic resin film is continuously increased from the hard coat layer side to the base material layer side. Since the concentration of the (meth) acrylic resin continuously changes, that is, the interface resulting from the concentration change of the (meth) acrylic resin is not formed, interface reflection can be suppressed, and interference unevenness is small. This is because an optical laminate can be obtained.

  The minimum of the thickness of the said osmosis | permeation layer is 1.0 micrometer, for example, Preferably it is 1.2 micrometers, More preferably, it is 1.5 micrometers, More preferably, it is 2 micrometers. The upper limit of the thickness of the permeation layer is preferably ((meth) acrylic resin film thickness × 70%) μm, more preferably ((meth) acrylic resin film thickness × 40%) μm, The thickness is preferably ((meth) acrylic resin film thickness × 30%) μm, particularly preferably ((meth) acrylic resin film × 20%) μm. When the thickness of the permeation layer is in such a range, an optical laminate having excellent adhesion between the (meth) acrylic resin film and the hard coat layer and suppressing interference unevenness can be obtained. In addition, the thickness of the osmosis | permeation layer can be measured by observation with electron microscopes, such as a reflection spectrum of a hard-coat layer, or SEM and TEM. Details of the method for measuring the thickness of the osmotic layer based on the reflection spectrum will be described later as an evaluation method in Examples.

D. Hard coat layer As described above, the hard coat layer is formed by coating the composition for forming a hard coat layer on the (meth) acrylic resin film. The composition for forming a hard coat layer includes, for example, a curable compound that can be cured by heat, light (such as ultraviolet rays), or an electron beam. Preferably, the composition for forming a hard coat layer contains a photocurable curable compound. The curable compound may be any of a monomer, an oligomer and a prepolymer.

  The hard coat layer forming composition includes, as essential components, one or more radically polymerizable unsaturated groups and a curable compound containing an aromatic ring (A) and two or more radically polymerizable unsaturated groups. And a curable compound (B) that does not contain an aromatic ring, and a monofunctional monomer (C) that contains one radical polymerizable unsaturated group but does not contain an aromatic ring. Examples of the radical polymerizable unsaturated group include a (meth) acryloyl group and a (meth) acryloyloxy group. According to the composition for forming a hard coat layer containing the above three kinds of curable compounds, the (meth) acrylic resin film and the hard are used even when the heating temperature (described later) of the coating layer at the time of forming the hard coat layer is set low. An optical laminate having excellent adhesion to the coating layer and hardness can be obtained.

  The curable compound (A) contains at least one radically polymerizable unsaturated group and one aromatic ring. The curable compound (A) can improve the cohesive strength of the compatibilized region between the (meth) acrylic resin and the hard coat layer forming component, and as a result, improves the adhesion between the base material layer and the hard coat layer. Can be. Further, since the curable compound (A) can increase the refractive index of the hard coat layer, an antireflection film having a lower reflectance is obtained when a low refractive index antireflection layer is laminated on the hard coat layer. be able to.

  The number of radically polymerizable unsaturated groups contained in the curable compound (A) is preferably 1 to 4. Moreover, the number of aromatic rings contained in the curable compound (A) is preferably 1 to 6. As an aromatic ring, a benzene ring, a heterocyclic ring, or these condensed rings can be illustrated. Preferably, the aromatic ring is a benzene ring. The aromatic ring may or may not have a substituent.

  Specific examples of the curable compound (A) include ethoxylated o-phenylphenol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, benzyl (meth) acrylate, 2-hydroxy-3-phenoxy (meth) acrylate, and phenoxy. Examples include monomers such as ethyl (meth) acrylate, aryl groups such as benzyl group and phenyl group, and (meth) acrylate oligomers or prepolymers containing a fluorene structure. A curable compound (A) may be used independently and may be used in combination of multiple.

  The molecular weight (weight average molecular weight in the case of an oligomer or polymer) of the curable compound (A) is preferably 250 or more, more preferably more than 450, and still more preferably 450 to 10,000. If the molecular weight is within the above range, the cohesive force of the compatibilized region can be sufficiently improved, so that an optical laminate having excellent adhesion between the base material layer and the hard coat layer can be obtained.

  The content ratio of the curable compound (A) to the total curable compound in the hard coat layer forming composition is 10% to 60% by weight, preferably 15% to 55% by weight, and more preferably. 20% by weight to 50% by weight. If it is such a range, the heating temperature at the time of hard coat layer formation can be set low, the heating time can be set short, and the deformation (for example, shrinkage of the (meth) acrylic resin film) due to heating is suppressed. A laminated body can be produced efficiently.

  The curable compound (B) contains two or more radically polymerizable unsaturated groups, but does not contain an aromatic ring. When the composition for forming a hard coat layer contains a polyfunctional curable compound (B) containing two or more radically polymerizable unsaturated groups, a hard coat layer having sufficient hardness can be formed.

  In one embodiment, the composition for forming a hard coat layer includes a curable compound (B1) containing 9 or more radically polymerizable unsaturated groups as the curable compound (B). When a hard coat layer-forming composition containing the curable compound (B1) is applied to form a hard coat layer, the components (representative) in the (meth) acrylic resin film eluted into the hard coat layer-forming composition Specifically, the resin component in the (meth) acrylic resin film) is prevented from diffusing to the air interface of the hard coat layer when the hard coat layer is formed, and an optical laminate having excellent hardness can be obtained. Preferably, a block layer made of the curable compound (B1) is formed on the hard coat layer. If the block layer is formed, an optical laminate having a higher hardness can be obtained. The number of radically polymerizable unsaturated groups contained in the curable compound (B1) is preferably 10 or more, more preferably 15 or more, and further preferably 20 to 100. The greater the number of radical polymerizable unsaturated groups contained in the curable compound (B1), the more the hardness of the hard coat layer itself can be improved.

  Examples of the curable compound (B1) include oligomers such as urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, triazine (meth) acrylate, and silicone (meth) acrylate. Prepolymers: Methacrylate polymers having unsaturated groups and the like. Among these, urethane (meth) acrylate oligomers or prepolymers are preferable from the viewpoint of reactivity and transparency. A curable compound (B1) may be used independently and may be used in combination of multiple.

  The urethane (meth) acrylate can be obtained, for example, by reacting hydroxy (meth) acrylate obtained from (meth) acrylic acid or (meth) acrylic acid ester and polyol with diisocyanate.

  Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like.

  Examples of the polyol include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1, 6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2,2,4-trimethyl-1,3-pentanediol, 3-methyl-1,5-pentanediol, neopentyl hydroxypivalate Glycol ester, tricyclodecane dimethylol, 1,4-cyclohexanediol, spiroglycol, hydrogenated bisphenol A, ethylene oxide-added bisphenol A, propylene oxide-added bisphenol A, trimethylol ethane, trimethylol Propane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, dipentaerythritol, tripentaerythritol, glucose, etc. can be mentioned.

  As said diisocyanate, various aromatic, aliphatic, or alicyclic diisocyanates can be used, for example. Specific examples of the diisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4,4-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3-dimethyl-4,4. -Diphenyl diisocyanate, xylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate, and hydrogenated products thereof.

  The weight average molecular weight of the curable compound (B1) is preferably 1000 or more, more preferably 1500 or more, and further preferably 2000 to 50000. Since the curable compound (B1) has 9 or more radically polymerizable unsaturated groups, even if the curable compound (B1) has a relatively small weight average molecular weight, the (meth) acrylic resin film Can be prevented from diffusing to the air interface of the hard coat layer, and an optical laminate having excellent hardness can be obtained. Of course, a curable compound (B1) having a higher weight average molecular weight may be used for the purpose of obtaining an optical layered body having higher hardness.

  In another embodiment, the composition for forming a hard coat layer may include a curable compound (B2) having 2 to 8 radically polymerizable unsaturated groups as the curable compound (B). In the other embodiment, the composition for forming a hard coat layer may contain only the curable compound (B2) as the curable compound (B), but a viewpoint of obtaining an optical laminate having more excellent hardness. Is preferable to contain both the curable compound (B1) and the curable compound (B2).

  The number of radically polymerizable unsaturated groups contained in the curable compound (B2) can be, for example, 2 to 6. If the composition for forming a hard coat layer contains a curable compound (B2) containing 2 to 6 radically polymerizable unsaturated groups, the heating temperature of the coating layer during the formation of the hard coat layer is set low. However, the optical laminated body which is excellent in the adhesiveness of a (meth) acrylic-type resin film and a hard-coat layer can be obtained.

  Examples of the curable compound (B2) include polyethylene glycol di (meth) acrylate, tricyclodecane dimethanol diacrylate, 1,10-decanediol diacrylate, 1,6-hexanediol diacrylate, and 1,9-nonane. Diol diacrylate, dipropylene glycol diacrylate, polypropylene glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dimethylolpropanthate tetraacrylate, trimethylolpropane triacrylate, ditrimethylolpropane Tetraacrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanedio (Meth) acrylate, isocyanuric acid tri (meth) acrylate, ethoxylated glycerol triacrylate, ethoxylated pentaerythritol tetraacrylate and compounds having (meth) acryloyl groups such as oligomers or polymers thereof; urethane (meth) acrylate, and These oligomers or prepolymers may be mentioned. These compounds may be used alone or in combination of two or more.

  The curable compound (B2) preferably has a hydroxyl group. If the composition for forming a hard coat layer contains such a curable compound (B2), the heating temperature at the time of forming the hard coat layer can be set lower, the heating time can be set shorter, and deformation due to heating can be achieved. It is possible to efficiently produce an optical laminate in which the above is suppressed. Moreover, the optical laminated body excellent in the adhesiveness of a (meth) acrylic-type resin film and a hard-coat layer can be obtained. Examples of the curable compound (B2) having a hydroxyl group include pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate.

  The weight average molecular weight of the curable compound (B2) is preferably 3000 or less, more preferably 2000 or less, further preferably 1500 or less, particularly preferably 1000 or less, and particularly preferably 500 or less. . By using the curable compound (B2) having a relatively small weight average molecular weight, the thickness of the permeation layer can be increased. As a result, an optical laminate having excellent adhesion between the (meth) acrylic resin film and the hard coat layer and having suppressed interference unevenness can be obtained.

  The content ratio of the curable compound (B) to the total curable compound in the hard coat layer forming composition is 30% by weight to 80% by weight, preferably 30% by weight to 75% by weight, and more preferably. It is 35 to 70% by weight, particularly preferably 40 to 60% by weight. If it is such a range, the optical laminated body which has sufficient hardness can be obtained.

  When the composition for forming a hard coat layer contains both the curable compound (B1) and the curable compound (B2), the blending weight ratio (B1 / B2) is, for example, 30/70 to 99/1, preferably May be 40/60 to 99/1, more preferably 50/50 to 99/1.

  The monofunctional monomer (C) contains one radical polymerizable unsaturated group, but does not contain an aromatic ring. Since the monofunctional monomer (C) easily penetrates into the (meth) acrylic resin film, the penetration layer can be suitably formed. Moreover, if the composition for forming the hard coat layer contains the monofunctional monomer (C), the heating temperature at the time of forming the hard coat layer can be set low, the heating time can be set short, and deformation due to heating is suppressed. An optical laminate can be produced efficiently.

  The weight average molecular weight of the monofunctional monomer (C) is preferably 500 or less, more preferably 300 or less, still more preferably less than 250, and particularly preferably less than 200. With such a monofunctional monomer, it easily penetrates and diffuses into the (meth) acrylic resin film. Examples of such monofunctional monomers include methoxypolyethylene glycol (meth) acrylate, 2-ethylhexyl acrylate, lauryl acrylate, isooctyl acrylate, isostearyl acrylate, cyclohexyl acrylate, isophoronyl acrylate, acryloylmorpholine, 2-hydroxyethyl. (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, dimethylaminopropylacrylamide, N- (2-hydroxyethyl) (meth) acrylamide, acryloylmorpholine and the like can be mentioned.

  The monofunctional monomer (C) preferably has a polar group such as a hydroxyl group, an ether, an amine (including a morpholine ring), and more preferably has a hydroxyl group. If it is such a monofunctional monomer, it is excellent in the permeability or solubility with respect to a (meth) acrylic-type resin film. As a result, the heating temperature at the time of forming the hard coat layer can be set lower, the heating time can be set shorter, and an optical layered body in which deformation due to heating is suppressed can be efficiently produced. Moreover, if the said composition for hard-coat layer formation contains the monofunctional monomer which has a hydroxyl group, the optical laminated body excellent in the adhesiveness of a (meth) acrylic-type resin film and a hard-coat layer can be obtained. Examples of such monofunctional monomers include hydroxyalkyl such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 1,4-cyclohexanemethanol monoacrylate. (Meth) acrylate; N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxyalkyl) (meth) acrylamide such as N-methylol (meth) acrylamide, cyclohexanedimethanol monoacrylate and the like. Of these, 4-hydroxybutyl acrylate and N- (2-hydroxyethyl) acrylamide are preferable.

  The boiling point of the monofunctional monomer (C) is preferably higher than the heating temperature (described later) of the coating layer when forming the hard coat layer. The boiling point of the monofunctional monomer is, for example, preferably 150 ° C. or higher, more preferably 180 ° C. or higher, and particularly preferably 200 ° C. or higher. If it is such a range, it can prevent that a monofunctional monomer volatilizes by the heating at the time of hard-coat layer formation, and a monofunctional monomer can fully osmose | permeate a (meth) acrylic-type resin film.

  The content ratio of the monofunctional monomer (C) to the total curable compound in the hard coat layer forming composition is preferably 10% by weight to 40% by weight, more preferably 12% by weight to 35% by weight, and still more preferably. Is from 15% to 30% by weight. If the content ratio of the monofunctional monomer (C) is within such a range, the heating temperature at the time of forming the hard coat layer can be set low, the heating time can be set short, and the optical laminate in which deformation due to heating is suppressed. Can be produced efficiently.

  The total content of the curable compound (A) and the monofunctional monomer (C) with respect to the total curable compound in the hard coat layer forming composition is preferably 20% by weight to 70% by weight, more preferably 30% by weight. % To 65% by weight, more preferably 40% to 60% by weight

  The hard coat layer forming composition preferably contains any appropriate photopolymerization initiator. Examples of the photopolymerization initiator include 2,2-dimethoxy-2-phenylacetophenone, acetophenone, benzophenone, xanthone, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, benzoinpropyl ether, benzyldimethyl Ketals, N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, thioxanthone compounds, etc. Can be mentioned.

  In one embodiment, the surface of the hard coat layer opposite to the base material layer has a concavo-convex structure. If the surface of the hard coat layer has a concavo-convex structure, antiglare properties can be imparted to the optical laminate. Examples of a method for forming such a concavo-convex structure include a method in which fine particles are contained in the hard coat layer forming composition. The fine particles may be inorganic fine particles or organic fine particles. Examples of the inorganic fine particles include silicon oxide fine particles, titanium oxide fine particles, aluminum oxide fine particles, zinc oxide fine particles, tin oxide fine particles, calcium carbonate fine particles, barium sulfate fine particles, talc fine particles, kaolin fine particles, and calcium sulfate fine particles. Examples of the organic fine particles include polymethyl methacrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, and polyester resin powder. , Polyamide resin powder, polyimide resin powder, polyfluorinated ethylene resin powder, and the like. These fine particles may be used alone or in combination.

  Any appropriate shape can be adopted as the shape of the fine particles. It is preferably a substantially spherical shape, more preferably a substantially spherical shape having an aspect ratio of 1.5 or less. The weight average particle diameter of the fine particles is preferably 1 μm to 30 μm, more preferably 2 μm to 20 μm. The weight average particle diameter of the fine particles can be measured by, for example, a Coulter count method.

  When the hard coat layer forming composition contains the fine particles, the content ratio of the fine particles is preferably 1% by weight to the total amount of the monomer, oligomer and prepolymer in the hard coat layer forming composition. 60% by weight, more preferably 2% by weight to 50% by weight.

  The composition for forming a hard coat layer may further contain any appropriate additive. Examples of additives include leveling agents, anti-blocking agents, dispersion stabilizers, thixotropic agents, antioxidants, UV absorbers, antifoaming agents, thickeners, dispersants, surfactants, catalysts, fillers, and lubricants. And antistatic agents.

  As said leveling agent, a fluorine type or silicone type leveling agent is mentioned, for example, Preferably, it is a silicone type leveling agent. Examples of the silicone leveling agent include reactive silicone, polydimethylsiloxane, polyether-modified polydimethylsiloxane, and polymethylalkylsiloxane. Of these, reactive silicone is preferable. If reactive silicone is added, the surface of the hard coat layer is provided with slipperiness and the scratch resistance is maintained for a long period of time. The content ratio of the leveling agent is preferably 5% by weight or less, more preferably 0.01% by weight to 5% by weight with respect to the total amount of the monomer, oligomer and prepolymer in the hard coat layer forming composition. %.

  The composition for forming a hard coat layer may or may not contain a solvent. Examples of the solvent include dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, acetone, methyl ethyl ketone (MEK). , Diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone (CPN), cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, ethyl acetate n -Pentyl, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pen Nord, 2-methyl-2-butanol, cyclohexanol, isopropyl alcohol (IPA), isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-heptanone, ethylene Examples include glycol monoethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether. These may be used alone or in combination.

  According to the present invention, a hard coat layer-forming composition containing no solvent, or a hard coat layer-forming composition containing only a poor solvent for the (meth) acrylic resin film-forming material as a solvent can be used. The forming composition can permeate the (meth) acrylic resin film to form a permeation layer having a desired thickness.

  The thickness of the hard coat layer is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 4 μm to 10 μm. If it is such a range, the optical laminated body excellent in hardness can be obtained. Moreover, since the optical laminated body of this invention suppresses the spreading | diffusion to the hard-coat layer (composition for hard-coat layer formation) of the component in a (meth) acrylic-type resin film as mentioned above, Even if the thickness is reduced, the hardness is excellent.

  As described above, the (meth) acrylic resin forming the (meth) acrylic resin film is eluted in the hard coat layer forming composition, and the (meth) acrylic resin is present in the hard coat layer. May be. In the present invention, since the hard coat layer is formed by the hard coat layer forming composition containing the polyfunctional curable compound (B), the (meth) acrylic resin moves to the surface side of the hard coat layer. It can be suppressed. In one embodiment, the density | concentration of the said (meth) acrylic-type resin becomes low continuously from the base material layer side of a osmosis | permeation layer to a hard-coat layer. In such an embodiment, the interface reflection is suppressed by the fact that the concentration of the (meth) acrylic resin continuously changes, that is, the interface resulting from the concentration change of the (meth) acrylic resin is not formed. And an optical laminated body with less interference unevenness can be obtained. In another embodiment, the (meth) acrylic resin and the composition for forming a hard coat layer are phase-separated, and a block layer is formed on the opposite side of the hard coat layer from the osmotic layer. Also in such embodiment, it is preferable that the density | concentration of the said (meth) acrylic-type resin becomes low continuously from the base material layer side of a osmosis | permeation layer to the hard-coat layer except a block layer.

The thickness of the block layer is preferably 1 μm to 10 μm, more preferably 2 μm to 5 μm.
In addition, the thickness of a block layer can be measured by observation with electron microscopes, such as a reflection spectrum of a hard-coat layer, or SEM and TEM.

E. Other Layers In the optical layered body of the present invention, any appropriate other layer may be disposed outside the hard coat layer as necessary. Typical examples include an antireflection layer and an antiglare layer. As the antireflection layer and the antiglare layer, an antireflection layer and an antiglare layer usually used in the art can be adopted.

F. Method for Producing Optical Laminate The method for producing an optical laminate of the present invention comprises applying a composition for forming a hard coat layer on a (meth) acrylic resin film to form a coating layer, and heating the coating layer. including. Preferably, the hard coat layer is formed by curing the coating layer after heating.

  Arbitrary appropriate methods can be employ | adopted as a coating method of the composition for hard-coat layer formation. Examples thereof include a bar coating method, a roll coating method, a gravure coating method, a rod coating method, a slot orifice coating method, a curtain coating method, a fountain coating method, and a comma coating method.

  The heating temperature of the coating layer can be set to an appropriate temperature according to the composition of the hard coat layer forming composition, and preferably set to be equal to or lower than the glass transition temperature of the resin contained in the (meth) acrylic resin film. Is done. When heated at a temperature not higher than the glass transition temperature of the resin contained in the (meth) acrylic resin film, an optical layered body in which deformation due to heating is suppressed can be obtained. The heating temperature of the coating layer is, for example, 50 ° C. or more and less than 100 ° C., preferably 50 ° C. or more and less than 80 ° C., more preferably 50 ° C. to 75 ° C. By heating at a temperature in such a range, the monomer, oligomer and / or prepolymer (particularly, the monofunctional monomer (C)) in the composition for forming the hard coat layer is excellent in the (meth) acrylic resin film. Penetration and diffusion. The permeation layer described in the above section C is formed by the hard coat layer forming composition and the (meth) acrylic resin film forming material that has permeated through the heating and the subsequent curing treatment. As a result, an optical laminate having excellent adhesion between the (meth) acrylic resin film and the hard coat layer and having suppressed interference unevenness can be obtained. In addition, when the composition for hard-coat layer formation contains a solvent, the apply | coated composition for hard-coat layer formation can be dried by the said heating.

  In one embodiment, the said heating temperature may be set according to the content rate of a sclerosing | hardenable compound (A) and a monofunctional monomer (C). For example, if the total content of the curable compound (A) and the monofunctional monomer (C) with respect to all curable compounds in the hard coat layer forming composition is 20% by weight to 70% by weight, it is less than 80 ° C. With this heating temperature, it is possible to obtain an optical layered body that is excellent in adhesion and hardness and that is free from interference unevenness and deformation due to heating, and can be an efficient manufacturing process with low environmental load.

  Any appropriate curing process can be adopted as the curing process. Typically, the curing process is performed by ultraviolet irradiation. The integrated light quantity of ultraviolet irradiation is preferably 200 mJ to 400 mJ.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. The evaluation methods in the examples are as follows. In Examples, unless otherwise specified, “parts” and “%” are based on weight.

(1) Pencil hardness About the hard coat layer side surface of the optical laminated body obtained by the Example and the comparative example, according to JISK5400 (load 500g), pencil hardness was measured and evaluated on the following references | standards.
○: Pencil hardness is 2H or more ×: Pencil hardness is H or less (2) Adhesion of hard coat layer Adhesion of the hard coat layer to the substrate film is determined by a cross-cut peel test (substrate) of JIS K-5400 (Number of eyes: 100) and evaluated according to the following criteria.
○: The number of peels is 0 ×: The number of peels is 1 or more (3) Interference unevenness On the base film side of the optical laminate obtained in Examples and Comparative Examples, a black acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd., After attaching 2 mm thick) via an acrylic pressure-sensitive adhesive, interference unevenness was visually observed under a three-wavelength fluorescent lamp and evaluated according to the following criteria.
○: No occurrence of interference unevenness ×: Generation of interference unevenness is observed (4) Thickness of penetration layer A black acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd.) is formed on the base layer side of the optical laminate obtained in Examples and Comparative Examples. , 2 mm thick) was pasted through an acrylic adhesive having a thickness of 20 μm. Next, the reflection spectrum of the hard coat layer was measured under the following conditions using an instantaneous multi-photometry system (trade name: MCPD3700, manufactured by Otsuka Electronics Co., Ltd.). From the peak position of the FFT spectrum, (hard coat layer + penetration layer) The thickness of was evaluated. The refractive index was measured using an Abbe refractometer (trade name: DR-M2 / 1550) manufactured by Atago Co., Ltd., selecting monobromonaphthalene as an intermediate solution.
Reflection spectrum measurement conditions Reference: Mirror Algorithm: FFT method Calculation wavelength: 450 nm to 850 nm
・ Detection conditions Exposure time: 20 ms
Lamp gain: Normal Integration count: 10 times / FFT method Film thickness range: 2 to 15 μm
Film thickness resolution: 24nm
Moreover, the thickness of the hard coat layer was evaluated by measuring the reflection spectrum of the laminate (R) below.
-Laminate (R): Implemented except that a PET base material (trade name: U48-3, refractive index: 1.60) manufactured by Toray Industries, Inc. was used as the base film, and the heating temperature of the coating layer was set to 60 ° C. Obtained in the same manner as in Example 1.
In addition, since the composition for forming a hard coat layer does not penetrate into the PET substrate used in the laminate, the thickness of only the hard coat layer is measured from the peak position of the FFT spectrum obtained from the laminate (R). The As a result of the evaluation, the thickness of the hard coat layer was 5.3 μm.
A positive value calculated from (thickness of (hard coat layer + penetration layer)) − (thickness of (hard coat layer)) was defined as the thickness of the permeation layer.

<Production Example 1> Production of Base Film A 100 parts by weight of imidized MS resin (weight average molecular weight: 105,000) described in Production Example 1 of JP 2010-284840 A and triazine-based ultraviolet absorber (ADEKA) (Product name: T-712) 0.62 parts by weight were mixed at 220 ° C. with a twin-screw kneader to prepare resin pellets. The obtained resin pellets were dried at 100.5 kPa and 100 ° C. for 12 hours, extruded from a T-die at a die temperature of 270 ° C. with a single screw extruder, and formed into a film (thickness: 160 μm). Further, the film is stretched in an atmosphere of 150 ° C. in the transport direction (thickness 80 μm), and then stretched in an atmosphere of 150 ° C. in a direction orthogonal to the film transport direction to form a base film A (( (Meth) acrylic resin film). The base film A thus obtained had a light transmittance of 8.5% at a wavelength of 380 nm, an in-plane retardation Re of 0.4 nm, and a thickness direction retardation Rth of 0.78 nm. In addition, the moisture permeability of the obtained base film A was 61 g / m ² · 24 hr. The light transmittance was measured by measuring a transmittance spectrum in a wavelength range of 200 nm to 800 nm using a spectrophotometer (device name: U-4100) manufactured by Hitachi High-Tech Co., Ltd., and reading the transmittance at a wavelength of 380 nm. . The phase difference value was measured at a wavelength of 590 nm and 23 ° C. using a trade name “KOBRA21-ADH” manufactured by Oji Scientific Instruments. The moisture permeability was measured by a method according to JIS K 0208 under conditions of a temperature of 40 ° C. and a relative humidity of 92%.

<Example 1>
30 parts of phenol novolac acrylate (product name “Hitaroid UV251”, manufactured by Hitachi Chemical Co., Ltd.) as the curable compound (A), and urethane acrylate oligomer (Mw = 2300, number of functional groups: 15 as the curable compound (B)) ) And dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “UA53H”), and hydroxybutyl acrylate as a monofunctional monomer (C) (manufactured by Osaka Organic Chemical Co., Ltd., product name “4- 20 parts of HBA ”, 0.5 part of a leveling agent (manufactured by DIC, trade name: PC4100) and 3 parts of a photopolymerization initiator (trade name: Irgacure 907, manufactured by Ciba Japan Co., Ltd.) A composition for forming a hard coat layer was prepared by diluting with methyl isobutyl ketone so that the partial concentration was 50%.

On the base film A obtained in Production Example 1, the obtained composition for forming a hard coat layer was applied to form a coating layer, and the coating layer was heated at 75 ° C. for 1 minute. The coated layer after heating was irradiated with ultraviolet light having an accumulated light amount of 300 mJ / cm ² with a high-pressure mercury lamp to cure the coated layer to form a base layer, a hard coat layer, and a penetrating layer, thereby obtaining an optical laminate. .

<Example 2>
An optical laminate was obtained in the same manner as in Example 1 except that 30 parts of a fluorene-containing acrylate oligomer (product name “EA-HR034” manufactured by Osaka Gas Chemicals Co., Ltd.) was used as the curable compound (A).

<Example 3>
An optical laminate was obtained in the same manner as in Example 1 except that 30 parts of a fluorene-containing acrylate oligomer (product name “HIC-GL”, manufactured by Kyoeisha Chemical Co., Ltd.) was used as the curable compound (A).

<Example 4>
Except that 30 parts of ethoxylated o-phenylphenol (meth) acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “A-LEN-10”) was used as the curable compound (A), the same procedure as in Example 1 was performed. An optical laminate was obtained.

<Example 5>
The amount of phenol novolac acrylate (manufactured by Hitachi Chemical Co., Ltd., product name “Hitaroid UV251”) was 50 parts, and the amount of curable compound (B) (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “UA53H”) An optical laminate was obtained in the same manner as in Example 1 except that the amount was 50 parts and the heating temperature was 65 ° C.

<Example 6>
50 parts of an oligomer of fluorene-containing acrylate (product name “EA-HR034” manufactured by Osaka Gas Chemicals Co., Ltd.) was used as the curable compound (A), and curable compound (B) (product name “manufactured by Shin-Nakamura Chemical Co., Ltd., product name“ An optical laminate was obtained in the same manner as in Example 1 except that the amount of UA53H ") was 50 parts and the heating temperature was 65 ° C.

<Example 7>
An optical laminate was obtained in the same manner as in Example 1 except that 30 parts of acryloylmorpholine (manufactured by Kojin Co., Ltd., product name “ACMO”) was used as the monofunctional monomer (C).

<Example 8>
An optical laminate was obtained in the same manner as in Example 1 except that 30 parts of cyclohexanedimethanol monoacrylate (manufactured by Nippon Kasei Co., Ltd., product name “CHDMMA”) was used as the monofunctional monomer (C).

<Comparative Example 1>
Example 1 except that the curable compound (A) was not added and that the amount of the curable compound (B) (product name “UA53H” manufactured by Shin-Nakamura Chemical Co., Ltd.) was 100 parts. Similarly, an optical laminate was obtained.

<Comparative Example 2>
The curable compound (A) was not added, the amount of the curable compound (B) (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “UA53H”) was 100 parts, and hydroxybutyl acrylate (Osaka Organic) An optical laminate was obtained in the same manner as in Example 1 except that the amount of the product of “Chemical Co., Ltd., product name“ 4-HBA ”” was 50 parts.

<Comparative Example 3>
An optical laminate was obtained in the same manner as in Example 1 except that the monofunctional monomer (C) was not added.

<Comparative Example 4>
The amount of phenol novolac acrylate (manufactured by Hitachi Chemical Co., Ltd., product name “Hitaroid UV251”) was 50 parts, and the amount of curable compound (B) (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “UA53H”) An optical laminate was obtained in the same manner as in Example 1 except that the amount was 100 parts and the monofunctional monomer (C) was not added.

<Comparative Example 5>
Except that 30 parts of fluorene-containing acrylate oligomer (product name “EA-HR034” manufactured by Osaka Gas Chemicals Co., Ltd.) was used as the curable compound (A), and that no monofunctional monomer (C) was added. In the same manner as in Example 1, an optical laminate was obtained.

<Comparative Example 6>
Except that the blending amount of phenol novolac acrylate (manufactured by Hitachi Chemical Co., Ltd., product name “Hitaroid UV251”) was 100 parts and that the curable compound (B) was not added, the same as in Example 1. Thus, an optical laminate was obtained.

Various characteristics of the optical laminates obtained in the above examples and comparative examples were evaluated. The evaluation results are shown in Table 1 together with the composition of the hard coat layer forming composition.

  As is clear from Table 1, the optical layered body of the example has a penetrating layer suitably formed at a heating temperature of less than 80 ° C., and no interference unevenness is observed. Furthermore, it is excellent in the adhesion between the hard coat layer and the base material layer, and also in the hardness. On the other hand, in the optical laminates of Comparative Examples 1 and 2 obtained using the composition for forming a hard coat layer not containing the aromatic ring-containing curable compound (A), a permeation layer was formed, and interference unevenness was observed. Although not possible, the adhesion is insufficient. Moreover, in the optical laminated body obtained by using the composition for forming a hard coat layer of Comparative Examples 3 to 5 that does not contain a monofunctional monomer (C), the formation of the permeation layer is insufficient, and as a result, adhesion And there is a problem with uneven interference. Moreover, in the optical laminated body of the comparative example 6 obtained using the composition for hard-coat layer formation which does not contain a polyfunctional curable compound (B), pencil hardness is H or less.

  The optical layered body of the present invention can be suitably used for an image display device. The optical layered body of the present invention can be suitably used as a front plate of an image display device or a protective material for a polarizer, and particularly suitably used as a front plate of a liquid crystal display device (in particular, a three-dimensional liquid crystal display device). obtain.

DESCRIPTION OF SYMBOLS 10 Base material layer 20 Penetration layer 30 Hard-coat layer 40 Block layer 100, 200, 300 Optical laminated body

Claims (13)

A base material layer formed from a (meth) acrylic resin film;
A hard coat layer formed by coating the (meth) acrylic resin film with a composition for forming a hard coat layer;
Between the base material layer and the hard coat layer, the hard coat layer forming composition comprises a permeation layer formed by permeating the (meth) acrylic resin film,
The hard coat layer-forming composition contains one or more radically polymerizable unsaturated groups and an aromatic ring-containing curable compound (A) and two or more radically polymerizable unsaturated groups, A curable compound (B) that does not contain a ring, and a monofunctional monomer (C) that contains one radical polymerizable unsaturated group but does not contain an aromatic ring,
Optical laminate.   The optical laminated body of Claim 1 whose content rate of the said sclerosing | hardenable compound (A) with respect to all the sclerosing | hardenable compounds in the said composition for hard-coat layer formation is 10 weight%-60 weight%.   The total content of the curable compound (A) and the monofunctional monomer (C) with respect to all curable compounds in the composition for forming a hard coat layer is 20% by weight to 70% by weight. 2. The optical laminate according to 2.   4. The hard coat layer forming composition according to claim 1, wherein the curable compound (B) includes a curable compound (B1) containing 9 or more radically polymerizable unsaturated groups. 5. The optical laminated body as described.   The optical laminated body according to any one of claims 1 to 4, wherein the monofunctional monomer (C) has a weight average molecular weight of 500 or less.   The optical laminate according to claim 1, wherein the monofunctional monomer (C) has a hydroxyl group.   The (meth) acrylic resin forming the (meth) acrylic resin film has a structural unit that exhibits positive birefringence and a structural unit that exhibits negative birefringence. The optical laminated body as described in.   The optical laminate according to any one of claims 1 to 7, wherein the (meth) acrylic resin forming the (meth) acrylic resin film has a weight average molecular weight of 10,000 to 500,000.   The optical laminate according to any one of claims 1 to 8, wherein a surface of the hard coat layer opposite to the penetration layer has an uneven structure.   The optical laminated body according to any one of claims 1 to 9, further comprising an antireflection layer on a side of the hard coat layer opposite to the penetration layer.   The polarizing film containing the optical laminated body in any one of Claim 1 to 10.   The image display apparatus containing the optical laminated body in any one of Claim 1 to 10. Applying a composition for forming a hard coat layer on a (meth) acrylic resin film to form a coating layer, and heating the coating layer at 50 ° C. or more and less than 100 ° C .;
The hard coat layer-forming composition contains one or more radically polymerizable unsaturated groups and an aromatic ring-containing curable compound (A) and two or more radically polymerizable unsaturated groups, The curable compound (B) containing no ring and the monofunctional monomer (C) containing one radical polymerizable unsaturated group but containing no aromatic ring, The manufacturing method of the optical laminated body of description.