KR102222794B1 - Polyester film and its manufacturing method, hard coat film and its manufacturing method, image display device and touch panel - Google Patents

Abstract

It is a polyester film with a thickness of 40 to 500 μm and an average of 30 to 100 MPa of the shear plane normal stress A in the slow axis direction in the surface layer 1 μm and the shear plane normal stress B in the direction orthogonal to the slow axis direction in the film plane. .

Description

Polyester film and its manufacturing method, hard coat film and its manufacturing method, image display device and touch panel

The present disclosure relates to a polyester film and a method for producing the same, a hard coat film and a method for producing the same, an image display device and a touch panel.

In applications in which chemically strengthened glass has been used, with the advancement of technology for increasing the hardness of a hard coat material, glass replacement of a hard coat film in which a hard coat layer is laminated on a base film is attracting attention. As an example of the hard coat film, the protective film of the outermost surface of an image display device, such as a touch panel, is mentioned.

For example, in Patent Literature 1, "as a laminated substrate in which a functional layer is formed on one side to form a laminate, a light-transmitting substrate having in-plane birefringence, and

A refractive index adjusting layer laminated with a light-transmitting substrate and having in-plane birefringence, comprising a refractive index adjusting layer positioned between the light-transmitting substrate and the functional layer,

_{The refractive index n 1x in} the slow axis direction, which is the direction with the largest refractive index in the plane of the _{light-transmitting substrate, and the refractive index n 2x} of the refractive index adjustment layer in a direction parallel to the slow axis direction of the light-transmitting substrate. _{, And the refractive index n 3x} of the functional layer in a direction parallel to the slow axis direction of the light-transmitting substrate,

n _1x <n _2x <n _3x , or n _1x >n _2x >n _3x

Meet the relationship of,

_{Refractive index n 1y in} the fast axis direction orthogonal to the slow axis direction of the _{light-transmitting substrate n 2y} , the refractive index n 2y of the refractive index adjusting layer in a direction parallel to the fast axis direction of the light-transmitting substrate, and light transmittance _{The refractive index n 3y} of the functional layer in a direction parallel to the fast axis direction of the substrate,

n _1y <n _2y <n _3y , or n _1y >n _2y >n _3y

A laminated substrate that satisfies the relationship of" is disclosed.

In Patent Document 2, "It has a laminated structure of at least three layers, and the polyester layer of the both outermost layer has a higher softening point than the middle layer, and a coating layer is formed on both sides of a multilayer polyester film, and an adhesive layer is formed on the surface of one coating layer. Disclosed is a surface protective film provided, wherein the coating layer is formed of a coating liquid containing 70% by weight or more of a crosslinking agent based on a nonvolatile component.

In Patent Document 3, "a uniaxially oriented polyester film having the following characteristics:

(1) On the surface of the film, there are no more than 1 scratch ^{per 1 m 2} with an elevation difference of 1 μm or more, and 20 or less per ^{1 m 2} scratches with an elevation difference of 0.3 μm or more and less than 1 μm,

(2) The film contains no more than one foreign substance per 1 ^{m 2 with a long diameter of 100 μm or more,}

(3) the three-dimensional average surface roughness (SRa) of the film surface is in the range of 0.020 to 0.060 μm, and

(4) The maximum distortion of the orientation principal axis of the film measured by a microwave transmission type molecular orientation meter is within 7 degrees." is disclosed.

In Patent Document 4, "a uniaxially oriented coextrusion laminated film composed of at least three polyester layers among layers A, B, and C, and the outermost layers, the A layer and the C layer, have an average particle diameter of 0.1 to 5.0 μm. Consisting of substantially homo-polyester containing 0.01 to 0.5% by weight of phosphorus inert particles, the intermediate layer B layer is a polyalkyl having a dicarboxylic acid component, an aliphatic or alicyclic diol component, and a number average molecular weight of 300 to 4000 Made of polyester containing 10 to 35% by weight of a polyalkylene ether glycol component and a ren ether glycol component as the main component, and the thickness ratio occupied by the total film thickness of the B layer is 65 to 95% A uniaxially oriented laminated polyester film characterized in that "is disclosed."

In Patent Document 5, "a polyester film which satisfies the following formula;

0m≤C _S <0.003L ² /8W

0m≤C _CT <0.003L ² /4W

0.8m≤W≤6.0m

20m≤L≤30m

In the formula, C _S [unit: m] represents the value of the entire width arc of the film, C _CT [unit: m] represents the value of the half-return arc at the center position in the width direction of the film, and W [unit: m ] Represents the film width, and L [unit: m] represents the film length at the time of measuring a full-width arc and a half-round arc." is disclosed.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2013-257550 Patent Document 2: Japanese Laid-Open Patent Publication No. 2015-128897 Patent Document 3: Japanese Laid-Open Patent Publication No. 2005-2220 Patent Document 4: Japanese Laid-Open Patent Publication No. 2004-351788 Patent Document 5: International Publication No. 2015/46122

In the films disclosed in Patent Documents 1 to 5, when the shear plane normal stress is insufficient and a load is applied locally in the thickness direction of the film, a recess is likely to occur. When a hard coat film obtained by laminating a hard coat layer on these films is produced and punching is performed, it is considered that cracking or peeling of the hard coat layer is liable to occur.

An object of the present disclosure is to provide a polyester film and a method of manufacturing the same, in which a recess is difficult to occur even when a load is applied locally in the thickness direction of the film.

In addition, the present disclosure aims to provide a hard coat film in which cracking and peeling of the hard coat layer hardly occur when punching by producing a hard coat film in which a hard coat layer is laminated on a polyester film, and a method for producing the same It is done.

In addition, an object of the present disclosure is to provide an image display device and a touch panel in which a decrease in visibility due to rainbow irregularities is suppressed even when a load is applied locally to a display screen.

In order to achieve the above object, the following means are provided.

<1> Poly with a thickness of 40 to 500 μm and an average of 30 to 100 MPa of the shear plane normal stress A in the slow axis direction in the surface layer 1 μm and the shear plane normal stress B in the direction orthogonal to the slow axis direction in the film plane. Ester film.

The polyester film according to <1>, which is for a base film of a <2> hard coat film.

The polyester film as described in <1> or <2> which is a <3> uniaxially oriented polyester film.

The polyester film according to any one of <1> to <3>, wherein the retardation Re in the film surface at a measurement wavelength of 589 nm of the <4> polyester film is 4000 to 500,000 nm.

<5> The average value of the shear surface yield stress in the slow axis direction in 1 μm of the surface layer of the polyester film and the shear surface yield stress in the direction orthogonal to the slow axis direction within the film surface is 20 to 60 MPa <1> to <4 > The polyester film according to any one of.

<6> The polyester film according to any one of <1> to <5>, wherein the ratio of the shear plane normal stress A to the shear plane normal stress B is 1.1 to 2.0.

The polyester film according to any one of <1> to <6>, wherein the ratio of the retardation Re in the film plane to the retardation Rth in the film thickness direction at a measurement wavelength of 589 nm of the <7> polyester film is 0.6 to 1.2.

<8> A hard coat film having a base film including the polyester film according to any one of <1> to <7>, and a hard coat layer laminated on at least one side of the base film.

The hard coat film according to <8>, in which the thickness of the <9> hard coat layer is 5 μm or more.

<10> the hard coat layer,

It contains at least the structure derived from the following a), the structure derived from the following b), the following c) and the following d),

When the hard coat layer has the total solid content of the hard coat layer as 100% by mass, the structure derived from a) is 15 to 70% by mass, the structure derived from b) is 25 to 80% by mass, and c) is 0.1 The hard coat film as described in <8> or <9> containing 0.1-10 mass% of -10 mass% and following d).

a) a compound having a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less

b) a compound having a group containing three or more ethylenically unsaturated double bonds in the molecule

c) radical polymerization initiator

d) cationic polymerization initiator

An image display device including a <11> image display element and the hard coat film according to any one of <8> to <10>, and in which a hard coat film is disposed on the outermost surface.

<12> The touch panel which contains the hard coat film in any one of <8>-<10>, and the hard coat film is arrange|positioned on the outermost surface.

<13> Using a transverse stretching device provided with a plurality of clips each running along a pair of rails provided on both sides of the film conveyance path,

A preheating step of preheating an unstretched or vertically stretched polyester film at a temperature rising rate of 600°C/min or less, and

While both edges of the preheated polyester film are gripped with a plurality of clips, transverse stretching is performed in a direction orthogonal to the film conveying path, and the surface temperature of the polyester film is gradually increased from the start of the transverse stretching to the end of the transverse stretching. Then, the surface temperature at the start of transverse stretching is 80°C or more and 95°C or less, and the surface temperature at the end of transverse stretching is controlled to 90°C or more and 105°C or less, and the transverse draw ratio is in the range of 3.3 times or more and 4.8 times or less. The transverse stretching process to be controlled, and

It includes a heat setting process of heat setting by heating the polyester film after the transverse drawing process to the maximum temperature in the transverse drawing apparatus,

A method for producing a polyester film for producing a polyester film having a thickness of 40 to 500 μm.

<14> In the transverse stretching step, the surface temperature is gradually increased at a temperature increase rate of 60° C./min or less, and the surface temperature when the transverse stretching ratio is in the range of 1× or more and less than 2× is 80° C. or more and 92° C. or less. , When the transverse draw ratio is in the range of 2 times or more and less than 3 times, the surface temperature is controlled to 85°C or more and 97°C or less, and when the transverse draw ratio is in the range of 3 times or more, the surface temperature is controlled to 90℃ or more and 102°C or less The method for producing the polyester film according to <13>.

<15> The rate of temperature increase of the surface temperature of the polyester film from the end of the transverse stretching step to reaching the maximum temperature in the heat setting step is controlled to 1000°C/min or less, and the polyester in the heat setting step Production of the polyester film according to <13> or <14>, wherein the maximum attainable surface temperature of the film is controlled to 130°C or more and 230°C or less, and the time when the surface temperature of the polyester film exceeds 130°C is controlled to 180 seconds or less. Way.

Production of the polyester film according to any one of <13> to <15>, which further includes a heat relaxation step of heating the polyester film after the <16> heat setting step and further reducing the length of the polyester film at least in the transverse direction Way.

<17> The process of manufacturing a polyester film by the manufacturing method of the polyester film in any one of <13>-<16>, and

A method for producing a hard coat film having a step of laminating a hard coat layer on at least one side of a polyester film.

According to the present disclosure, even if a load is applied locally in the thickness direction of the film, there is provided a polyester film and a method of manufacturing the same, in which the recess is unlikely to occur.

In addition, according to the present disclosure, a hard coat film in which cracks and peeling of the hard coat layer are hard to occur when punching is performed by producing a hard coat film in which a hard coat layer is laminated on a polyester film, and a method for producing the same are provided. .

Further, according to the present disclosure, an image display device and a touch panel are provided in which a decrease in visibility due to a rainbow unevenness is suppressed even when a load is applied locally to the display screen.

1 is a perspective view showing an example of a cutting blade used in a method of measuring shear surface normal stress and shear surface yield stress of a film surface layer.
Fig. 2 is a schematic diagram illustrating a method of measuring shear surface normal stress and shear surface yield stress of a film surface layer.
3 is a schematic diagram showing an example of a configuration of a transverse stretching device.

Hereinafter, the present disclosure will be described in detail. The description of the constitutional requirements described below may be made based on representative embodiments or specific examples, but the present disclosure is not limited to such embodiments. In addition, in this specification, the numerical range shown using "~" means a range including the numerical value described before and after "~" as a lower limit value and an upper limit value. In addition, when a unit is attached to one of the numerical values described before and after "~", it means that it is the same unit in the entire numerical range.

[Polyester film]

The polyester film according to the present embodiment (hereinafter, also simply referred to as "film") has a thickness of 40 to 500 μm, and the shear plane normal stress A in the slow axis direction in the surface layer 1 μm and the slow axis direction in the film plane The average value of the normal stress B in the shear plane in the orthogonal direction is 30 to 100 MPa.

Here, the "ground axis direction" of the film is a direction in which the refractive index is maximized in the film plane, and the direction orthogonal to the slow axis direction in the film plane is also referred to as "fast axis direction".

The production method of the polyester film according to the present embodiment will be described in detail later, but for example, after melt-extrusion of the polyester resin composition into a film shape, it is conveyed using a roll or the like, and at least in the conveying direction of the film ( When a polyester film is produced by stretching in a direction perpendicular to the longitudinal direction or the longitudinal direction of the film (also referred to as the width direction or the transverse direction of the film), the width direction of the film is usually the slow axis direction. In addition, when producing a polyester film as described above, the conveying direction of the film is sometimes referred to as MD (Machine Direction), and the direction orthogonal to the conveying direction of the film is referred to as TD (Transverse Direction).

<Characteristics of polyester film>

(thickness)

The thickness of the polyester film according to the present embodiment is 40 to 500 μm.

When the thickness of the polyester film is 40 μm or more, it has sufficient rigidity and is easy to use as a glass substitute material, and when it is 500 μm or less, the rigidity is not excessively strong, and the punchability and handling properties of the film are good.

From such a viewpoint, the thickness of the polyester film according to the present embodiment is more preferably 60 to 400 μm, and still more preferably 80 to 300 μm.

In addition, the thickness of the polyester film according to the present embodiment is sampled at 50 points each in the slow axis direction of the film and in the direction orthogonal to the slow axis direction in the film plane using, for example, a contact-type film thickness measuring system, The average thickness of the measured values of the thickness in these points is calculated|required, and it is set as the thickness of a polyester film.

(Normal shear stress)

In the polyester film according to the present embodiment, the average value of the shear surface normal stress A in the slow axis direction in the surface layer 1 μm and the shear surface normal stress B in the direction orthogonal to the slow axis direction in the film surface (hereinafter referred to as "surface average It may be referred to as "the shear plane normal stress") is 30 to 100 MPa. Here, “surface layer 1 μm” means a region from the surface of the polyester film to a depth of 1 μm.

When the surface layer average shear plane vertical stress in the surface layer 1 μm is 30 MPa or more, when the hard coat layer is laminated on a polyester film to form a hard coat film, when the film is pressed with a strong force, it is difficult to generate a recess in the film, and if it is 100 MPa or less When it is set as a hard coat film, cracking or peeling hardly occurs in a hard coat layer.

From such a viewpoint, the surface layer average shear plane normal stress of the polyester film according to the present embodiment is preferably 40 to 90 MPa, and more preferably 50 to 80 MPa.

In addition, in the polyester film according to the present embodiment, it is preferable that the ratio (A/B) of the shear surface normal stress A to the shear surface normal stress B is 1.1 to 2.0.

When the ratio A/B of the shear plane normal stress of the polyester film according to the present embodiment is 1.1 or more, it is easy to produce a uniaxially oriented polyester film in which rainbow unevenness is suppressed, and when it is 2.0 or less, it is hard on the polyester film. When a coat layer is laminated to form a hard coat film, cracking or peeling hardly occurs in the hard coat layer.

From such a viewpoint, the ratio A/B of the shear plane normal stress of the polyester film according to the present embodiment is more preferably 1.2 to 1.9, and still more preferably 1.3 to 1.8.

(Shear surface yield stress)

In the polyester film according to the present embodiment, the average value of the shear surface yield stress in the slow axis direction in the surface layer 1 μm and the shear surface yield stress in the direction orthogonal to the slow axis direction in the film plane (hereinafter, "surface average shear surface It is preferable that it is 20-60 MPa) in some cases called "yield stress". When the surface layer average shear surface yield stress of the polyester film according to the present embodiment is 20 MPa or more, when the hard coat layer is laminated on the polyester film to form a hard coat film, even if the film is pressed with a strong force, it is difficult to generate a recess in the film. If it is 60 MPa or less, cracking or peeling hardly occurs in the hard coat layer when it is set as a hard coat film.

From such a viewpoint, the surface layer average shear surface yield stress of the polyester film according to the present embodiment is more preferably 25 to 55 MPa, and still more preferably 30 to 50 MPa.

Here, the measurement of shear surface normal stress and shear surface yield stress of the film surface layer in the present embodiment will be described. 1 and 2 are schematic diagrams illustrating a method of measuring shear surface normal stress and shear surface yield stress of a film surface layer. The measuring apparatus, the measurement conditions, and the calculation method of shear surface normal stress and shear surface yield stress are as follows.

(1) measuring device

For the measurement of the shear surface normal stress and shear surface yield stress of the film surface layer in the present embodiment, SAICAS (Surface And Interfacial Cutting Analysis System)-NN type (manufactured by Daipla Wintes Co., Ltd.) is used. SAICAS controls the cutting blade speed, _{and can monitor the vertical force (F v} ) and the horizontal force (F _H ) applied to the cutting blade 10, and the vertical displacement (d) of the cutting blade.

(2) Measurement conditions

First, the inclination angle α and the clearance angle (cutting angle) γ of the cutting blade 10 with respect to the surface of the film 12 are respectively set to predetermined angles, and are cut from the film surface to the inside by the cutting blade ( Fig. 1(A)).

Shear fracture occurs due to the incision by the cutting blade 10, and the cutting force is monitored (Fig. 1(B)).

The film 12 is cut to a depth of 1 μm in the surface layer, and the stress (film strength) acting on the shear surface is evaluated (FIG. 1(C)).

Here, the measurement conditions are as follows.

Cutting speed: horizontal speed 100nm/s, vertical speed 10nm/s

Blade width: 0.1mm

· Inclined angle (α): 20°

·Cutting angle (γ): 10°

Blade type: Diamond cutting blade

Direction: Measured in slow axis direction and fast axis direction (TD, MD) respectively

Measure 3 points along each direction at 10mm intervals, and make the average value for each direction

(3) Calculation of shear plane normal stress and shear plane yield stress

In Fig. 2, the direction of the force applied when the sample (polyester film) 12 is cut at the cutting angle γ in the order of Fig. 1 (A) to (C) using a cutting blade having an inclination angle α. Show. The force acting parallel to the shear plane AB of the sample (F _S ) and the force acting perpendicularly (F _N ) are each of the following using the horizontal force (F _H ), the vertical force (F _V ), and the shear angle (φ) to be monitored. It is obtained as Equation (1).

Equation (1)

[Equation 1]

_{The stress (τ s} ; shear surface yield stress) acting parallel to the shear plane (the plane indicated by dotted line AB in Fig. 2) and the stress acting perpendicularly (σ _s ; shear plane normal stress) are F _S and F _{By dividing N by the area A s} of the shear plane, it is obtained by the following formula (2), respectively. In addition, b is the blade width, and d is the cutting depth (vertical displacement).

Equation (2)

[Equation 2]

In addition, the shear angle (phi) is obtained by the following formula (3) using the inclination angle (α) and the friction angle (β).

Equation (3)

[Equation 3]

That is, by calculating the shear angle (α) from the _{horizontal force (F H} ) and the vertical force (F _V ) at each depth, the depth direction distribution of the _{shear surface yield stress (τ s} ) or shear surface vertical stress (σ _{s) is calculated.} can do.

It is preferable that the polyester film according to this embodiment is a polyester film of uniaxial orientation. By transversely stretching and heat setting the melt-formed or solution-formed unstretched polyester film by the method described later, it is easy to obtain a polyester film having the above-described thickness and shear plane normal stress.

-Re (Retardation in the film side)-

In the polyester film according to the present embodiment, it is preferable that the retardation Re in the film surface at a measurement wavelength of 589 nm is 4000 to 500,000 nm.

When Re of the polyester film according to the present embodiment is 4000 nm or more, it is difficult to visually recognize the rainbow irregularity, and when it is 50000 nm or less, the required film thickness does not become excessively thick, and excessively strong rigidity is suppressed, and handling becomes easy.

From this point of view, Re in the measurement wavelength 589 nm of the polyester film according to the present embodiment is more preferably 5000 to 40000 nm, and still more preferably 7000 to 33000 nm.

-Re/Rth-

In addition, in the polyester film according to the present embodiment, it is preferable that the ratio (Re/Rth) of the retardation Re in the film plane to the retardation Rth in the film thickness direction at a measurement wavelength of 589 nm is 0.6 to 1.2.

When the Re/Rth of the polyester film according to the present embodiment at a measurement wavelength of 589 nm is 0.6 or more, it is difficult to visually recognize the rainbow irregularity, and when it is 1.2 or less, the film is difficult to break.

From such a viewpoint, as for Re/Rth of the polyester film according to the present embodiment, 0.7 to 1.15 are more preferable, and 0.8 to 1.1 are more preferable.

The retardation Rth in the thickness direction in the measurement wavelength 589 nm of the polyester film according to the present embodiment is preferably 3000 to 800,000 nm, more preferably 4000 to 600,000 nm, and still more preferably 6000 to 400,000 nm. When Rth is 3000 nm or more, it is easy to make a film, and when it is 80000 nm or less, when the hard coat film using the polyester film according to the present embodiment is applied to, for example, a display screen of an image display device, it is difficult to generate a rainbow unevenness on the screen. It is desirable.

Rainbow non-uniformity can also be reduced by setting the Nz value representing the relationship between Re and Rth to an appropriate value, and from the reduction effect of rainbow non-uniformity and manufacturing suitability, the Nz value is preferably an absolute value of 2.0 or less, and 0.5 to 2.0. It is more preferable and it is still more preferable that it is 0.5-1.5.

Since the rainbow unevenness is caused by incident light, it is usually observed during white display.

The retardation Re in the film surface of the polyester film according to the present embodiment is represented by the following formula (4).

Equation (4): Re=(nx-ny)×y ₁

Here, nx is the refractive index in the in-plane slow axis direction of the polyester film, ny is the refractive index in the in-plane fast axis direction (direction orthogonal to the in-plane slow axis direction) of the _{polyester film, and y 1} is the thickness of the polyester film. .

The retardation Rth in the thickness direction of the polyester film according to the present embodiment is represented by the following formula (5).

Equation (5): Rth={(nx+ny)/2-nz}×y ₁

Here, nz is the refractive index of the polyester film in the thickness direction.

In addition, the Nz value of a polyester film is represented by the following formula.

Nz=(nx-nz)/(nx-ny)

In the present specification, Re, Rth, and Nz at a wavelength of λnm can be measured as follows.

Using two polarizing plates, the orientation axis direction (ground axis direction and fast axis direction) of the polyester film is obtained, and a 4 cm x 2 cm rectangle is cut out so that the orientation axis direction is orthogonal to obtain a sample for measurement. For this sample, the refractive index (Nx, Ny) of the two axes orthogonal, and the refractive index (Nz) in the thickness direction were determined by an Abbe refractometer (manufactured by Atago, NAR-4T, measurement wavelength 589 nm), and the absolute value of the difference in refractive index of the two axes (|Nx-Ny|) was set as the anisotropy (ΔNxy) of the refractive index. The thickness y ₁ (nm) of the polyester film was measured using an electric micrometer (manufactured by Feinpruf GmbH, Millitron 1245D), and the unit was converted to nm. Re, Rth, and Nz were respectively calculated from the measured values of Nx, Ny, Nz, and y _1.

Re and Rth described above can be adjusted by the type of polyester resin used in the film, the amount of the polyester resin and additives, the addition of the retardation expressing agent, the film thickness of the film, the stretching direction and elongation of the film, and the like.

The method of controlling Re and Re/Rth of the polyester film according to the present embodiment in the respective ranges is not particularly limited, but can be achieved by, for example, a stretching method.

<Constituent material, layer structure, and surface treatment of polyester film>

The polyester film according to this embodiment contains a polyester resin. The mass ratio of the polyester resin occupied in the entire film is usually 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more.

The polyester film according to the present embodiment may be a single layer film of a layer containing a polyester resin as a main component, or a multilayer film having at least one layer containing a polyester resin as a main component.

In addition, the polyester film according to the present embodiment may be subjected to surface treatment on both sides or one side of the film. The surface treatment may be surface modification by corona treatment, saponification treatment, heat treatment, ultraviolet irradiation, electron beam irradiation, or the like, or may be thin film formation by coating or evaporation of a polymer or metal.

The polyester film according to the present embodiment may have an easily adhesive layer on at least one side.

The thickness of the easily adhesive layer contained in the polyester film according to the present embodiment is preferably 30 to 300 nm, more preferably 40 to 200 nm, and still more preferably 50 to 150 nm.

When the thickness of the easily-adhesive layer is 30 nm or more, the cushioning effect due to the easily-adhesive layer is easily obtained, and excessive increase in shear surface normal stress and shear surface yield stress is suppressed. In addition, when the thickness of the easily adhesive layer is 300 nm or less, the cushioning effect of the easily adhesive layer is not excessively strong, and it is suppressed that the shear surface normal stress and the shear surface yield stress are excessively lowered.

It is more preferable that the easily-adhesive layer contains particles, and the height at which the particles protrude from the surface of the easily-adhesive layer is equal to or greater than the film thickness of the easily-adhesive layer.

The height at which the particles protrude from the surface of the easily-adhesive layer is an average value at five points in the easily-adhesive layer having a square of 1 mm.

If the height at which the particles contained in the easily-adhesive layer protrude from the surface of the easily-adhesive layer is less than the film thickness of the easily-adhesive layer (preferably the coating layer), the sliding property tends to decrease and wrinkles tend to occur. .

The type of the particles is not particularly limited, and specific examples include particles such as silica, calcium carbonate, magnesium carbonate, valium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, titanium oxide, and zirconium oxide. These are mentioned, Preferably they are silica, aluminum oxide, titanium oxide, and zirconium oxide. In addition, heat-resistant organic particles described in Japanese Unexamined Patent Publication No. 59-5216, Japanese Unexamined Patent Publication No. 59-217755, and the like may be used. Examples of these other heat-resistant organic particles include thermosetting urea resin, thermosetting phenol resin, thermosetting epoxy resin, benzoguanamine resin, and the like.

As for the particle diameter, it is preferable that the height at which the particles protrude from the surface of the easily adhesive layer is equal to or greater than the film thickness of the easily adhesive layer. Although it is preferable to use particles adjusted to the primary average particle diameter, as a result, particles may be aggregated so that the height at which the particles protrude from the surface of the easily adhesive layer is equal to or greater than the film thickness of the easily adhesive layer. In the case of agglomerated particles, the height at which the particles protrude from the surface of the easily-adhesive layer can be confirmed by measuring the secondary average particle diameter.

(1-1) Polyester resin

As the polyester resin contained in the polyester film according to the present embodiment, for example, a polyester resin having the composition of WO2012/157662 is preferably used.

As a specific polyester resin, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polycyclohexanedimethylene terephthalate (PCT), etc. can be used. PET and PEN are more preferred, more preferably PET. In addition, PEN tends to have a slightly smaller Re/Rth.

As the polyester resin, polyethylene terephthalate is most preferred, but polyethylene naphthalate can also be preferably used, and for example, polyethylene naphthalate described in Japanese Patent Application Laid-Open No. 2008-39803 can be preferably used.

Polyethylene terephthalate is a polyester having a structural unit derived from terephthalic acid as a dicarboxylic acid component and a structural unit derived from ethylene glycol as a diol component, and 80 mol% or more of the total repeating units is ethylene terephthalate. Or, a structural unit derived from another copolymerization component may be included. As other copolymerization components, isophthalic acid, p-β-oxyethoxybenzoic acid, 4,4'-dicarboxydiphenyl, 4,4'-dicarboxybenzophenone, bis(4-carboxyphenyl)ethane, adipic acid, Dicarboxylic acid components such as sebacic acid, 5-sodium sulfoisophthalic acid, and 1,4-dicarboxycyclohexane, propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexane Diol components, such as diol, an ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, are mentioned. These dicarboxylic acid components and diol components can be used in combination of two or more as necessary. Moreover, it is also possible to use together an oxycarboxylic acid, such as p-oxybenzoic acid, with the said carboxylic acid component or a diol component. As other copolymerization components, a dicarboxylic acid component and/or a diol component containing a small amount of amide bond, urethane bond, ether bond, carbonate bond, and the like may be used.

Examples of the production method of polyethylene terephthalate include a so-called direct polymerization method in which terephthalic acid and ethylene glycol, other dicarboxylic acids and/or other diols are directly reacted if necessary, dimethyl ester of terephthalic acid and ethylene glycol, and other if necessary. Any production method such as a so-called transesterification reaction method in which dimethyl ester of dicarboxylic acid and/or other diol is transesterified can be applied.

(1-2) Physical properties of polyester resin

(1-2-1) Intrinsic viscosity

The intrinsic viscosity IV (Intrinsic Viscosity) of the polyester resin is preferably 0.5 or more and 0.9 or less, more preferably 0.52 or more and 0.8 or less, and still more preferably 0.54 or more and 0.7 or less. To achieve such IV, when synthesizing a polyester resin, in addition to melt polymerization described later, solid-phase polymerization may be used in combination.

(1-2-2) Acetaldehyde content rate

It is preferable that the acetaldehyde content of the polyester resin is 50 ppm or less. It is more preferably 40 ppm or less, particularly preferably 30 ppm or less. Acetaldehyde easily causes a condensation reaction between acetaldehyde and water is produced as a side-reactant, and hydrolysis of polyester may proceed by this water. In reality, the lower limit of the acetaldehyde content is about 1 ppm. In order to make the acetaldehyde content within the above range, keeping the oxygen concentration in each process such as melt polymerization and solid-phase polymerization during the production of the resin low, keeping the oxygen concentration low during storage and drying the resin, and film production At the time, a method such as reducing the heat history applied to the resin by an extruder, a melt pipe, a die, or the like, preventing a local strong shear from being applied due to a screw configuration of the extruder at the time of melting, or the like can be adopted.

(1-3) catalyst

In the polymerization of the polyester resin, Sb, Ge, Ti, and/or Al-based catalysts are used, preferably Sb, Ti, and/or Al-based catalysts, more preferably Al-based catalysts.

That is, it is preferable that the polyester resin used as the raw material resin is a resin polymerized using an aluminum catalyst.

By using an Al-based catalyst, it becomes easier to express Re than in the case of using other catalysts (for example, Sb or Ti), and thinning of PET becomes possible. In other words, it means that orientation is easier to use with an Al-based catalyst. It is estimated that this is due to the following reasons.

The Al-based catalyst has a lower reactivity (polymerization activity) than the Sb-based catalyst or the Ti-based catalyst, so the reaction is mild, and it is difficult to generate a by-product (diethylene glycol unit: DEG).

As a result, the regularity of PET becomes high, and it is easy to orientate and Re is easily expressed.

(1-3-1) Al-based catalyst

As the Al-based catalyst, the Al-based catalyst described in [0013] to [0148] of WO2011/040161 ([0021] to [0123] of US2012/0183761) can be used, and the contents described in these publications are incorporated herein by reference. .

The method of producing a polyester resin by polymerization using an Al-based catalyst is not particularly limited, but specifically, [0091] to [0094] of WO2012/008488 ([0144] to [0153] of US2013/0112271) It can be polymerized according to, and the contents described in these publications are incorporated herein by reference.

In addition, the Al-based catalyst is, for example, [0052] to [0054], [0099] to [0104] of Japanese Laid-Open Patent Publication No. 2012-122051 ([0045] to [0047], [0091] of WO2012/029725). It can be prepared according to), and the contents described in these publications are incorporated herein by reference.

The amount of the Al-based catalyst is preferably 3 to 80 ppm, more preferably 5 to 60 ppm, and still more preferably 5 to 40 ppm as the amount of the Al element relative to the mass of the polyester resin.

(1-3-2) Sb-based catalyst:

As the Sb-based catalyst, the Sb-based catalysts described in [0050] and [0052] to [0054] of JP 2012-41519 A can be used.

The method of polymerizing the polyester resin using the Sb-based catalyst is not particularly limited, but specifically, polymerization may be performed according to [0086] to [0087] of WO2012/157662.

(1-4) Additive:

It is also preferable to add a known additive to the polyester film according to the present embodiment. Examples thereof include ultraviolet absorbers, particles, lubricants, anti-blocking agents, heat stabilizers, antioxidants, antistatic agents, light resistance agents, impact resistance improving agents, lubricants, dyes, pigments, and the like. However, since a polyester film generally requires transparency, it is preferable to minimize the amount of additives added.

(1-4-1) Ultraviolet (UV) absorber:

In the polyester film according to the present embodiment, an ultraviolet absorber may be contained in order to prevent the liquid crystal of the liquid crystal display from deteriorating due to ultraviolet rays. The ultraviolet absorber is a compound having ultraviolet absorbing ability, and is not particularly limited as long as it is an ultraviolet absorber capable of withstanding the heat added in the manufacturing process of the polyester film.

As the ultraviolet absorber, there are organic ultraviolet absorbers and inorganic ultraviolet absorbers, and from the viewpoint of transparency, organic ultraviolet absorbers are preferable. The ultraviolet absorber described in [0057] of WO2012/157662 or the cyclic iminoester-based ultraviolet absorber described later can be used.

Although it is not limited to the following as a cyclic iminoester type ultraviolet absorber, For example, 2-methyl-3,1-benzoxazine-4-one, 2-butyl-3,1-benzoxazine-4-one , 2-phenyl-3,1-benzoxazin-4-one, 2-(1- or 2-naphthyl)-3,1-benzoxazin-4-one, 2-(4-biphenyl)- 3,1-benzoxazine-4-one, 2-p-nitrophenyl-3,1-benzoxazine-4-one, 2-m-nitrophenyl-3,1-benzoxazine-4- One, 2-p-benzoylphenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1-benzoxazin-4-one, 2-o-methoxyphenyl-3 ,1-benzoxazine-4-one, 2-cyclohexyl-3,1-benzoxazine-4-one, 2-p-(or m-)phthalimidophenyl-3,1-benzoxazine-4 -One, N-phenyl-4-(3,1-benzoxazine-4-on-2-yl)phthalimide, N-benzoyl-4-(3,1-benzoxazine-4-one-2 -Yl)aniline, N-benzoyl-N-methyl-4-(3,1-benzoxazine-4-one-2-yl)aniline, 2-(p-(N-methylcarbonyl)phenyl)-3 ,1-benzoxazine-4-one, 2,2'-bis(3,1-benzoxazine-4-one), 2,2'-ethylenebis(3,1-benzoxazine-4-one) ), 2,2'-tetramethylenebis(3,1-benzoxazine-4-one), 2,2'-ethylenebis(3,1-benzoxazine-4-one, 2,2'-( 1,4-phenylene) bis (4H-3,1-benzoxazine-4-one) (also referred to as 2,2'-p-phenylene bis (3,1-benzoxazine-4-one)) ], 2,2'-m-phenylene bis (3,1-benzoxazine-4-one), 2,2'- (4,4'-diphenylene) bis (3,1-benzox) Photo-4-one), 2,2'-(2,6- or 1,5-naphthylene)bis(3,1-benzoxazine-4-one), 2,2'-(2-methyl- p-phenylene)bis(3,1-benzoxazine-4-one), 2,2'-(2-nitro-p-phenylene)bis(3,1-benzooxazin-4-one) , 2,2'-(2-chloro-p-phenylene)bis(3,1-benzoxazine-4-one), 2,2'-(1,4-cyclohexylene)bis(3,1 -Benzoxazin-4-one), 1,3,5-tri(3,1-benzoxazine-4-on-2-yl)benzene, 1,3,5-tri(3,1-benzooxy) Photo-4-on-2-yl)naphthalene, 2,4,6-tri(3,1-benzo Oxazine-4-one-2-yl)naphthalene, 2,8-dimethyl-4H,6H-benzo(1,2-d;5,4-d')bis(1,3)-oxazine-4 ,6-dione, 2,7-dimethyl-4H,9H-benzo(1,2-d;4,5-d')bis(1,3)-oxazine-4,9-dione, 2 ,8-diphenyl-4H,8H-benzo(1,2-d;5,4-d')bis(1,3)-oxazine-4,6-dione, 2,7-diphenyl-4H ,9H-benzo(1,2-d;4,5-d')bis(1,3)-oxazine-4,6-dione, 6,6'-bis(2-methyl-4H,3, 1-benzoxazine-4-one), 6,6'-bis(2-ethyl-4H,3,1-benzoxazine-4-one), 6,6'-bis(2-phenyl-4H, 3,1-benzoxazine-4-one), 6,6'-methylenebis(2-methyl-4H,3,1-benzoxazine-4-one), 6,6'-methylenebis(2- Phenyl-4H,3,1-benzoxazine-4-one), 6,6'-ethylenebis(2-methyl-4H,3,1-benzoxazine-4-one), 6,6'-ethylene Bis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,6'-butylenebis(2-methyl-4H,3,1-benzoxazine-4-one), 6 ,6'-butylenebis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,6'-oxybis(2-methyl-4H,3,1-benzoxazine-4 -One), 6,6'-oxybis(2-phenyl-4H,3,1-benzoxazine-4-one), 6,6'-sulfonylbis(2-methyl-4H,3,1- Benzooxazin-4-one), 6,6'-sulfonylbis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-carbonylbis(2-methyl- 4H,3,1-benzoxazine-4-one), 6,6'-carbonylbis(2-phenyl-4H,3,1-benzoxazin-4-one), 7,7'-methylenebis (2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-methylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), 7,7 '-Bis(2-methyl-4H,3,1-benzoxazine-4-one), 7,7'-ethylenebis(2-methyl-4H,3,1-benzoxazine-4-one), 7,7'-oxybis(2-methyl-4H,3,1-benzoxazine-4-one), 7,7'-sulfonylbis(2-methyl-4H,3,1-benzoxazine- 4-one), 7,7'-carbonylbis(2-methyl-4H,3,1-benzoxazine-4-one), 6,7'-bis(2-methyl-4H,3,1 -Benzoxazine-4-one), 6,7'-bis(2-phenyl-4H,3,1-benzoxazine-4-one, 6,7'-methylenebis(2-methyl-4H,3) ,1-benzoxazine-4-one), 6,7'-methylenebis(2-phenyl-4H,3,1-benzoxazine-4-one), and the like.

Among the above compounds, when the color tone is considered, a benzoxazine-based compound that does not exhibit yellow color is suitably used, and, for example, a compound represented by the following formula (6) is more suitably used.

Equation (6)

[Formula 1]

In the above formula (6), R represents a divalent aromatic hydrocarbon group, and X ¹ and X ² are each independently selected from a hydrogen atom or the following functional group groups, but are not necessarily limited thereto.

Functional group group: alkyl group, aryl group, heteroaryl group, halogen, alkoxyl group, aryloxy group, hydroxyl group, carboxyl group, ester group, nitro group.

Among the compounds represented by the above formula (6), 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazine-4-one) is particularly preferable.

The amount of the ultraviolet absorber that may be contained in the polyester film according to the present embodiment is usually 10.0% by mass or less, preferably in the range of 0.3 to 3.0% by mass with respect to the entire film. When the ultraviolet absorber in an amount exceeding 10.0% by mass is contained, the ultraviolet absorber may bleed out on the surface, resulting in a decrease in surface functionality such as a decrease in adhesion.

In addition, when the polyester film according to the present embodiment has a laminated structure, it is preferably at least a three-layer structure, and the ultraviolet absorber is preferably blended in an intermediate layer (a layer other than the outermost layer). By blending the ultraviolet absorber in the intermediate layer, it is possible to prevent the ultraviolet absorber from bleeding out to the film surface, and as a result, properties such as adhesion of the film can be maintained.

In the formulation of the ultraviolet absorber, for example, the master batch method described in [0050] to [0051] of WO2011/162198 can be used.

(1-4-2) Other additives

In the polyester film according to the present embodiment, other additives may be used, for example, the additives described in WO2012/157662 can be used, and the contents described in this publication are incorporated herein by reference.

[Method of manufacturing polyester film]

Using a transverse stretching device having a plurality of clips each running along a pair of rails provided on both sides of the film conveyance path,

A preheating step of preheating an unstretched or vertically stretched polyester film at a temperature rising rate of 600°C/min or less, and

In a state where both edges of the preheated polyester film are gripped with a plurality of clips, transverse stretching is performed in a direction orthogonal to the film conveying path, and the surface temperature of the polyester film from the start of the transverse stretching to the end of the transverse stretching (hereinafter, The surface temperature at the start of transverse stretching is 80°C or more and 95°C or less, and the surface temperature at the end of transverse stretching is controlled to 90°C or more and 105°C or less. Thus, the transverse stretching step of controlling the transverse stretching ratio in a range of 3.3 times or more and 4.8 times or less, and

Including a heat setting step of heat setting by heating the polyester film after the transverse stretching step to the maximum temperature in the transverse stretching device,

This is a method for producing a polyester film for producing a polyester film having a thickness of 40 to 500 μm.

Here, "unstretched polyester film" means a polyester film having both MD and TD refractive indexes of 1.590 or less, for example, a polyester film having a refractive index of both MD and TD of 1.590 or less, such as minor stretching in MD Films and the like are also substantially included in the unstretched polyester film.

Hereinafter, as a preferred embodiment of the method for producing a polyester film according to the present embodiment, a case where an unstretched polyester film is formed by melt extrusion and then stretched in the transverse direction to produce a uniaxially oriented polyester film is described. do.

<Melt kneading>

It is preferable that the unstretched polyester film is molded into a film shape by melting and extruding a polyester resin.

It is preferable to dry the polyester resin or the master batch of the polyester resin and the additive produced by the above-described master batch method to a moisture content of 200 ppm or less, and then introduce it to a single-screw or twin-screw extruder to melt it. At this time, in order to suppress the decomposition of the polyester resin, it is also preferable to melt in nitrogen or in vacuum. Detailed conditions, for example, by employing [0051] to [0052] of Japanese Patent Publication No. 4962661 ([0085] to [0086] of US2013/0100378) can be carried out according to these publications, and the contents described in these publications are It is incorporated herein by reference. It is also preferable to use a gear pump in order to increase the delivery precision of the molten resin (melt). In addition, it is also preferable to use a filter having a pore diameter of 3 μm to 20 μm for removing foreign matter.

<extrusion or coextrusion>

It is preferable to extrude the melt containing the polyester resin melt-kneaded from a die, but may be extruded in a single layer or extruded in multiple layers (coextrusion). In the case of extruding into multiple layers, for example, a layer containing an ultraviolet absorber (UV agent) and a layer not including the layer may be stacked, and a three-layer configuration with a layer containing a UV agent as an inner layer is a polarizer by ultraviolet rays. In addition to suppressing deterioration, it is preferable to suppress bleed-out of the UV agent.

The bleeding-out UV agent is transferred to the roll in contact with the film in the film manufacturing process, and increases the friction coefficient between the film and the roll, which is not preferable because abrasion is liable to occur.

When the polyester film is produced by extruding into multiple layers, the thickness (ratio to the entire layer) of the preferable inner layer (layer other than the outermost layer) of the obtained polyester film is preferably 50% or more and 95% or less, and more preferably It is 60% or more and 90% or less, More preferably, it is 70% or more and 85% or less. Such lamination can be performed by using a feed block die or a multi-manifold die.

<cast>

For example, according to Japanese Patent Application Laid-Open No. 2009-269301 [0059], it is preferable to extrude a melt extruded from a die onto a casting drum, cool and solidify, to obtain an undrawn polyester film (original).

In the method for producing a polyester film according to the present embodiment, the refractive index in the longitudinal direction (MD) of the unstretched polyester film is preferably 1.590 or less, more preferably 1.585 or less, and still more preferably 1.580 or less.

In the method for producing a polyester film according to the present embodiment, the crystallinity of the unstretched polyester film is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. In addition, the crystallinity degree of the unstretched polyester film mentioned here means the crystallinity degree of the central part of the film width direction (TD).

When adjusting the degree of crystallinity, the temperature at the end of the casting drum may be lowered, or air may be blown onto the cast drum.

The degree of crystallinity can be calculated from the density of the film. That is, using the density X (g/cm ³ ) of the film, the density Y=1.335g/cm ³ at 0% crystallinity, and the density Z=1.501g/cm ³ at 100% crystallinity, the crystallinity (%) from the following calculation formula Can be derived.

Crystallinity = {Z×(X-Y)}/{X×(Z-Y)}×100

In addition, the measurement of the density is performed according to JIS K7112.

<Formation of polymer layer>

The melt-extruded unstretched polyester film may be formed by coating a polymer layer according to the purpose before or after stretching to be described later.

As a polymer layer, a functional layer which a polarizing plate may have in general is mentioned, Among them, it is preferable to form an easily adhesive layer. The easily adhesive layer can be applied by the method described in [0062] to [0070] of WO2012/157662, for example.

<Preheat>

3 schematically shows an example of a configuration of a transverse stretching device used in a transverse stretching step.

As a preheating step up to the start of stretching in the transverse stretching step, it is preferable to preheat the unstretched polyester film at a temperature increase rate of 600°C/min or less. If the temperature rising rate of the film until the start of stretching in the transverse stretching process is 600°C/min or less, the molecular chains are stretched in a state where they have started to move sufficiently, and the shear plane normal stress and the shear plane yield stress are excessively increased. It is suppressed.

From this point of view, the temperature increase rate in the preheating step is more preferably 500° C./min or less, and still more preferably 400° C./min or less.

The rate of temperature increase in the preheating step may be 40°C/min or more and 600°C/min or less, 40°C/min or more and 500°C/min or less, or 40°C/min or more and 400°C/min or less.

<Horizontal Stretching>

In the lateral stretching process, as shown in FIG. 3, a lateral stretching device having a plurality of clips 20 running along a pair of rails provided on both sides of the film conveying path (also called a "tenter-type stretching device" or a "tenter" ), horizontal stretching is performed while both edges of the unstretched polyester film are held by the clips 20, respectively. In addition, you may grip the unstretched polyester film with a clip at the stage of the preheating process.

There is no restriction|limiting in particular as a transverse stretching apparatus which has the clip 20 which runs along a pair of rails provided on both sides of a film conveyance path. As for the pair of rails, a pair of endless rails is usually used. Also, the clip is in motion with the gripping member.

The unstretched polyester film is stretched horizontally. Transverse stretching is performed in the direction (TD) orthogonal to the film conveyance direction (MD), conveying the unstretched polyester film along the film conveyance path. That is, transverse stretching can be achieved by grasping both ends of the film with a clip and expanding the width between the clips while heating.

By transverse stretching, the retardation Re in the in-plane direction can be largely expressed. In particular, in order to achieve a polyester film satisfying the preferable ranges of Re and Re/Rth, it is preferable to perform at least transverse stretching. Moreover, you may perform longitudinal stretching before a preheating process or before a transverse stretching process.

The surface temperature at the start of stretching in the transverse stretching step is preferably 80°C or more and 95°C or less, more preferably 82°C or more and 93°C or less, and still more preferably 84°C or more and 92°C or less.

If the surface temperature at the start of stretching in the transverse stretching step is 80°C or higher, orientation and orientation crystallization do not proceed excessively in the stretching step, and excessive increase in shear surface normal stress and shear surface yield stress is suppressed. Moreover, the rise of Rth is suppressed, the Re/Rth ratio becomes 0.6 or more, and the visibility of the rainbow unevenness is suppressed.

When the surface temperature at the start of stretching in the transverse stretching step is 95°C or less, the growth of spheroids due to insufficient orientation is suppressed, and the shear plane normal stress and the shear plane yield stress fall excessively, and the film Cloudiness is suppressed, and Re is easy to rise sufficiently.

In the method for producing a polyester film according to the present embodiment, the surface temperature at the end of stretching in the transverse stretching step is preferably 90°C or more and 105°C or less, more preferably 92°C or more and 102°C or less, and 93°C. It is more preferably more than or equal to 100°C.

If the surface temperature at the end of stretching in the transverse stretching step is 90°C or higher, orientation and orientation crystallization do not proceed excessively in the stretching step, and excessive increase in shear plane normal stress and shear plane yield stress is suppressed. Moreover, the rise of Rth is suppressed, the Re/Rth ratio becomes 0.6 or more, and the visibility of the rainbow unevenness is suppressed.

When the surface temperature at the end of stretching in the transverse stretching step is 105°C or less, the growth of spheroids due to insufficient orientation is suppressed, the shear plane normal stress and the shear plane yield stress excessively fall, and the film is suppressed from clouding. And, Re, which affects the suppression of the rainbow unevenness, tends to rise sufficiently.

The surface temperature is gradually increased from the beginning of the stretching to the end of the stretching in the transverse stretching step. Here, "slowly rising" may be increased continuously or stepwise.

The difference between the surface temperature at the end of stretching and at the beginning of stretching is preferably 1°C or higher, more preferably 3°C or higher, and most preferably 5°C or higher.

If the surface temperature is gradually increased from the start of the stretching to the end of the stretching, the formation of spheroids is more difficult, and excessive orientation is suppressed, and it is easy to achieve both Re and Re/Rth in a preferable range, and the rainbow non-uniformity is visually recognized. It becomes difficult to become.

The transverse stretching ratio in the transverse stretching step is preferably controlled in a range of 3.3 times or more and 4.8 times or less, more preferably 3.5 times or more and 4.5 times or less, and still more preferably 3.7 times or more and 4.3 times or less.

When the transverse draw ratio is 3.3 times or more, excessive fall of the shear surface normal stress and shear surface yield stress of the film is suppressed, and the decrease in Re, which is effective in suppressing the rainbow unevenness, is suppressed. When the transverse draw ratio is 4.8 times or less, the shear plane normal stress and the shear plane yield stress of the film rise excessively and breakage is suppressed.

In the transverse stretching step, the surface temperature when the transverse draw ratio is in the range of 1 to 2 times is preferably 80°C or more and 92°C or less, more preferably 82°C or more and 91°C or less, and 84°C or more and 91°C The following are more preferable.

When the surface temperature in the transverse stretching process is in the range of 1 times or more and less than 2 times, if the surface temperature is 80°C or more, orientation and orientation crystallization do not proceed excessively in the stretching step, and shear surface normal stress and shear surface yield stress This excessive rise is suppressed. Moreover, the increase of Rth is suppressed, the Re/Rth ratio becomes 0.6 or more, and the visibility of the rainbow non-uniformity is suppressed.

When the surface temperature in the transverse stretching ratio in the transverse stretching step is in the range of 1 times or more and less than 2 times, when the surface temperature is 92°C or less, the growth of spheroids due to insufficient orientation is suppressed, and the shear plane normal stress and the shear plane yield stress are It is suppressed that falling excessively and that Re does not rise sufficiently and that the rainbow unevenness is visually recognized.

In the transverse stretching step, the surface temperature when the transverse draw ratio is in the range of 2 times or more and less than 3 times is preferably 85° C. or more and 97° C. or less, more preferably 86° C. or more and 97° C. or less, and 87° C. or more and 96° C. The following are more preferable.

In the transverse stretching process, if the surface temperature when the transverse draw ratio is in the range of 2 times or more and less than 3 times is 85°C or more, orientation and orientation crystallization do not proceed excessively in the stretching step, and shear surface normal stress and shear surface yield stress This excessive rise is suppressed. Moreover, the rise of Rth is suppressed, the Re/Rth ratio becomes 0.6 or less, and the visibility of the rainbow unevenness is suppressed.

In the transverse stretching process, when the surface temperature in the range of 2 times or more and less than 3 times the transverse draw ratio is 97°C or less, the growth of spheroids due to lack of orientation is suppressed, and the shear plane normal stress and the shear plane yield stress are reduced. Excessive descent is suppressed. In addition, Re, which is effective in suppressing the rainbow non-uniformity, is sufficiently increased, and the visibility of the rainbow non-uniformity is suppressed.

In the transverse stretching step, the surface temperature when the transverse draw ratio is in the range of 3 times or more is preferably 90°C or more and 102°C or less, more preferably 92°C or more and 101°C or less, and still more preferably 93°C or more and 100°C or less. Do.

In the transverse stretching process, if the surface temperature when the transverse draw ratio is in the range of 3 times or more is 90°C or more, orientation and orientation crystallization do not proceed excessively in the stretching step, and the shear plane normal stress and the shear plane yield stress are excessively increased. It is suppressed. Moreover, the rise of Rth is suppressed, the Re/Rth ratio becomes 0.6 or more, and it is suppressed that the rainbow unevenness is visually recognized.

In the transverse stretching process, if the surface temperature when the transverse draw ratio is in the range of 3 times or more is 102°C or less, the growth of spheroids due to lack of orientation is suppressed, and the shear plane normal stress and the shear plane yield stress fall excessively. Is suppressed. Moreover, Re rises sufficiently, and the visibility of the rainbow non-uniformity is suppressed.

In addition, since the surface temperature is gradually increased from the beginning of the stretching to the end of the stretching, in the lateral stretching step, the surface temperature and the lateral stretching ratio are 2 or more times when the lateral stretching ratio is within a range of 1 to 2 times. The surface temperature when the range is less than 3 times and the surface temperature when the transverse draw ratio is in the range of 3 times or more do not fall below the surface temperature in the range at the time of stretching with a small transverse draw ratio. That is, the surface temperature when the transverse draw ratio is in the range of 2 times or more and less than 3 times does not fall below the surface temperature when the transverse draw ratio is in the range of 1 to less than 2 times, and the transverse draw ratio is in the range of 3 times or more. The surface temperature at the time of is not less than the surface temperature when the transverse draw ratio is in the range of 2 times or more and less than 3 times.

In the transverse stretching step, the rate of temperature increase of the surface temperature during stretching is preferably 60°C/min or less, more preferably 50°C/min or less, and still more preferably 40°C/min or less.

In the transverse stretching process, if the rate of temperature increase of the surface temperature during stretching is 60°C/min or less, rapid movement of molecular chains during stretching is suppressed, and excessive fall of shear surface normal stress and shear surface yield stress is suppressed. . Moreover, Re, which is effective in suppressing the rainbow unevenness, rises sufficiently, and it becomes difficult to visually recognize the rainbow unevenness.

In the transverse stretching process, the rate of temperature increase of the surface temperature during stretching is 5°C/min or more and 60°C/min or less, 5°C/min or more and 50°C/min or less, or 5°C/min or more and 40°C/min or less. do.

<Fixed heat>

A heat setting step of heat setting by heating the polyester film after transverse stretching to the maximum temperature in the transverse stretching device is included.

After stretching, a heat treatment called "heat fixation" is performed in order to promote crystallization. By performing at a temperature exceeding the stretching temperature, crystallization can be promoted and the strength of the film can be increased.

In heat setting, the volume contracts for crystallization.

The heat setting method can be achieved by providing a number of slits for sending hot air to the stretched portion in parallel in the width direction, and raising the temperature of the gas ejected from the slits higher than that of the stretched portion.

Further, a heat source (IR heater, halogen heater, etc.) may be provided in the vicinity of the extension (part) outlet and the temperature may be increased.

130 to 230 degreeC is preferable, 150 to 210 degreeC is more preferable, and 160 to 200 degreeC is more preferable as for the highest attainable surface temperature of the polyester film in a heat setting process.

When the maximum attainable surface temperature in the heat setting process is 130°C or more, excessive fall of shear surface normal stress and shear surface yield stress is suppressed, and when 230°C or less, shear surface normal stress and shear surface yield stress excessively increase. It is suppressed.

The rate of temperature increase of the surface temperature of the film from the end of the transverse stretching step to reaching the maximum temperature in the heat setting step is preferably 1000°C/min or less, more preferably 800°C/min or less, and 700°C/min The following are more preferable.

Here, "the highest temperature in the heat setting process" refers to the highest point of the surface temperature reached by the film in the heat setting zone, and by measuring the surface temperature (film surface temperature) of the film in the heat setting zone with a radiation thermometer You can get it.

If the temperature increase rate of the film in the heat setting step from the end of the transverse stretching step is 1000°C/min or less, the rapid relaxation of molecules before crystallization is suppressed, and the shear plane normal stress and the shear plane yield stress fall excessively, or Since Re does not rise sufficiently, it is suppressed that the rainbow unevenness is visually recognized.

The rate of temperature increase of the surface temperature of the film from the end of the transverse stretching step to reaching the maximum temperature in the heat setting step is 50°C/min or more and 1000°C/min or less, 50°C/min or more and 800°C/min or less, Alternatively, it may be 50°C/min or more and 700°C/min or less.

The time when the surface temperature exceeds 130°C is preferably 180 seconds or less, more preferably 120 seconds or less, and still more preferably 60 seconds or less.

When the time when the surface temperature exceeds 130° C. is 180 seconds or less, crystallization does not proceed excessively, the shear plane normal stress and the shear plane yield stress excessively rise, or Rth rises excessively, and the rainbow unevenness is suppressed from being visually recognized.

The time when the surface temperature exceeds 130°C may be 10 seconds or more and 180 seconds or less, 10 seconds or more and 120 seconds or less, or 10 seconds or more and 60 seconds or less.

<heat relief>

It is preferable to include a heat relaxation step of heating the polyester film after the heat setting step and further reducing the length of the polyester film at least in the transverse direction (TD). In other words, before releasing the polyester film after transverse stretching from the clip, a heat setting step of heating the polyester film after transverse stretching to the maximum temperature in the transverse stretching device, and a pair of heating the polyester film after the heat setting step It is preferable to include a thermal relaxation step of narrowing the distance between rails.

In addition, the thermal relaxation step is not strictly limited to the mode performed after the heat setting step, and the heat setting step and the thermal relaxation step may be performed simultaneously. In the case of performing the heat setting process and the heat relaxation process at the same time, the heat setting process is the point where the temperature is heated to the maximum temperature in the transverse stretching device, and continuous thermal relaxation is performed at a temperature that does not exceed the maximum temperature in the transverse stretching device. desirable.

After the heat setting step, it is preferable to perform relaxation (to shrink the film) simultaneously with the heat treatment, and to perform at least one of TD (horizontal direction) and MD (vertical direction) is preferable.

Transverse relaxation can be achieved by reducing the width of the enlarged clip.

Such relaxation can be achieved, for example, by using a pantograph-shaped chuck for the tenter, reducing the gap between the pantograph, and driving the clip on an electromagnet to reduce this speed.

In the heat relaxation process, it is preferable to reduce the MD length of the heat-set polyester film, which is 1 to 7%, from the viewpoint of suppressing the occurrence of scratches on the polyester film, and 2 to 6 % Is more preferable, and 3 to 5% are more preferable. When the relaxation rate of MD is 1% or more, the thermal contraction rate of MD can be made small, and wrinkles become difficult to generate|occur|produce. If the relaxation rate of the MD is 7% or less, it is difficult to cause sagging in the MD during the relaxation treatment, and it is difficult to cause a planar failure, which is preferable.

It is preferable from the viewpoint of suppressing the occurrence of scratches on the polyester film, and more preferably 1 to 4%, 1 to 3% is more preferable. If the relaxation rate of the TD is 6% or less, it is difficult to cause sagging in the TD during relaxation treatment, and it is difficult to cause a planar failure, which is preferable.

The relaxation temperature of TD (transverse direction) is preferably within the range of the heat setting temperature described above, and is the same temperature as the heat setting as long as heat setting of heating the polyester film after transverse stretching to the maximum temperature in the transverse stretching device can be performed ( That is, even if it reaches the maximum temperature in the transverse stretching device), it may be low.

By performing the above preheating step, transverse stretching step, heat setting step, and thermal relaxation step performed as necessary, it becomes easy to achieve Re, Rth, Re/Rth of the polyester film according to the present embodiment, and rainbow non-uniformity is reduced. It is easy to produce the polyester film according to the present embodiment that exhibits the effect of.

<cooling>

It is preferable to include the step of cooling the polyester film after heat setting or before releasing the polyester film after heat relaxation from the clip. It is preferable that the polyester film after heat setting or heat relaxation is cooled before being released from the clip from the viewpoint of making it easier to lower the temperature of the clip when the polyester film is released from the clip.

The cooling temperature of the polyester film after heat setting or heat relaxation is preferably 80°C or less, more preferably 70°C or less, and particularly preferably 60°C or less.

As a method of cooling the polyester film after heat setting, a method of specifically applying cold air to the polyester film is mentioned.

In addition, as a temperature control means for heating or cooling the polyester film in preheating, stretching, heat setting, heat relaxation, and cooling in the present embodiment, hot air or cold air is applied to the polyester film, or poly What makes the ester film come into contact with the surface of a metal plate which can control a temperature, or makes it pass through the vicinity of a metal plate is mentioned.

<Film Liberation from Clip>

After going through the above process, the polyester film is released from the clip.

It is preferable to control the surface temperature of the polyester film when the polyester film is detached from the clip in the range of 40 to 140°C. When the polyester film detaches from the clip, the surface temperature of the polyester film is more preferably 50°C or more and 120°C or less, and still more preferably 60°C or more and 100°C or less.

In the method for producing a polyester film according to the present embodiment, the thickness of the polyester film after completion of film formation (after the release step from the clip) is 40 μm or more and 500 μm or less, more preferably 60 μm or more and 400 μm or less, and 80 μm or more and 300 μm or less. Is more preferred. The reason why it is preferable to make the thickness of a polyester film into the said range is the same as the reason for the film thickness of the polyester film concerning this embodiment mentioned above.

<Recovery, slit, and winding of film>

After release from the clip, the film is trimmed, slit, and knurled as necessary, and wound up for recovery.

In the method for producing a polyester film according to the present embodiment, a film width of 0.8 to 6 m after being released from the clip is preferable from the viewpoint of effectively securing the product width of the film and not increasing the device size, and is preferably 1 to 5 m. It is more preferable that it is, and it is especially preferable that it is 1-4m. The optical film requiring precision is usually formed to be less than 3 m, but in the present embodiment, it is preferable to form a film with the same width as described above.

Moreover, you may wind up after sliting the film which formed into a wide film to be preferably 2 or more and 6 or less, more preferably 2 or more and 5 or less, and still more preferably 3 or more and 4 or less.

After the slit, it is preferable to knurling (knurling) both ends.

It is preferable to wind 1000m or more and 10000m or less on a winding core having a diameter of 70mm or more and 600mm or less. The winding tension per cross-sectional area of the film ^{is preferably 3 to 30 kgf/cm 2} , more preferably 5 to 25 kgf/cm ² , and still more preferably 7 to 20 kgf/cm ² . Moreover, it is also preferable to attach a masking film before winding up.

[Hard coat film]

The polyester film according to the present embodiment can be suitably used for a base film of a hard coat film.

That is, the hard coat film according to the present embodiment has a base film including the polyester film according to the present embodiment described above, and a hard coat layer laminated on at least one side of the polyester film.

<Hard coat layer>

Hereinafter, the hard coat layer of the hard coat film according to the present embodiment will be described.

The hard coat layer may be formed by either a wet coating method or a dry coating method (vacuum film forming), but it is preferably formed by a wet coating method excellent in productivity.

As a hard coat layer, for example, JP 2013-45045 A, JP 2013-43352 A, JP 2012-232459 A, JP 2012-128157 A, JP 2011- 131409, JP 2011-131404, JP 2011-126162, JP 2011-75705, JP 2009-286981, JP 2009-263567, JP Patent Publication No. 2009-75248, JP 2007-164206 A, JP 2006-96811 A, JP 2004-75970 A, JP 2002-156505 A, JP 2001-272503 A hard coat layer described in No., WO12/018087, WO12/098967, WO12/086659, and WO11/105594 can be used.

(Thickness of the hard coat layer)

The thickness of the hard coat layer of the hard coat film according to the present embodiment is preferably 5 μm or more. When the thickness of the hard coat layer is 5 μm or more, a hard coat film having high scratch resistance is obtained.

From such a viewpoint, the thickness of the hard coat layer of the hard coat film according to the present embodiment is more preferably 10 μm or more, and still more preferably 15 μm or more.

In addition, when the thickness of the hard coat layer is excessively thick, the punching process tends to become difficult, so the thickness of the hard coat layer is preferably 40 μm or less, and more preferably 35 μm or less.

(Materials of the hard coat layer)

The hard coat layer of the hard coat film according to the present embodiment,

It contains at least the structure derived from the following a), the structure derived from the following b), the following c) and the following d),

When the hard coat layer has the total solid content of the hard coat layer as 100% by mass, the structure derived from a) is 15 to 70% by mass, the structure derived from b) is 25 to 80% by mass, and c) is 0.1 It is preferable to contain 0.1-10 mass% of -10 mass% and following d).

a) a compound having a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less

b) a compound having a group containing three or more ethylenically unsaturated double bonds in the molecule

c) radical polymerization initiator

d) cationic polymerization initiator

By providing the hard coat layer having such a configuration, the hard coat film according to the present embodiment has high pencil hardness and excellent smoothness, and a change in the appearance of the film after aging of moist heat is suppressed.

In this embodiment, it is preferable that the hard coat layer has a hard coat property. In this specification, the hard coat property means that it is a pencil hardness of 7H or more from the viewpoint of using it as an outermost surface protective film of an image display device as a glass replacement hard coat film. It is preferable that the hard coat layer has a pencil hardness of 8H or more.

It is preferable that the hard coat film according to the present embodiment having such a configuration is produced by the method for producing a hard coat film according to the present embodiment described later.

<Configuration>

It is preferable that the hard coat film according to the present embodiment is a configuration in which a hard coat layer is applied on at least one surface of the polyester film according to the present embodiment described above. The hard coat film according to the present embodiment is formed by curing a composition for forming a hard coat layer including a), b), c) and d), and the composition for forming a hard coat layer is used for forming a hard coat layer. When the total solid content of the composition is 100% by mass, a) is 15 to 70% by mass, b) is 25 to 80% by mass, c) is 0.1 to 10% by mass, and d) is 0.1 to 10% by mass. It is more preferable.

<Composition for forming a hard coat layer and a hard coat layer>

Hereinafter, the details of each component contained in the hard coat layer and the composition for forming a hard coat layer will be described.

[a) A compound having a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less]

The hard coat film according to the present embodiment contains 15 to 70 mass% of the structure derived from the following a) when the hard coat layer makes the total solid content of the hard coat layer 100 mass%.

a) A compound having a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less.

In addition, the hard coat layer is formed by curing a composition for forming a hard coat layer comprising at least a), b), c) and d), and the composition for forming a hard coat layer is the entire composition for forming a hard coat layer. When the solid content is 100% by mass, it is preferable to contain 15 to 70% by mass of a).

A) A compound contained in the composition for forming a hard coat layer having a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less will be described. a) A compound having a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less is also referred to as "a) component".

Examples of the group containing an ethylenically unsaturated double bond include polymerizable functional groups such as (meth)acryloyl group, vinyl group, styryl group, and allyl group, and among them, (meth)acryloyl group and -C(O )OCH=CH ₂ is preferable, and particularly preferably a (meth)acryloyl group. By having a group containing an ethylenically unsaturated double bond, high hardness can be maintained and heat-and-moisture resistance can also be imparted.

In addition, in this specification, "(meth)acryloyl group" is the meaning including "acryloyl group" and "methacryloyl group", and "(meth)acrylate" means "acrylate" and " It means inclusive of "methacrylate", and "(meth)acryl" means inclusive of "acrylic" and "methacrylic".

In this embodiment, the number of groups containing an epoxy group and an ethylenically unsaturated double bond in the molecule is one. When the number of each functional group is one, compared to the case of two or more, the number of functional groups (a group containing an epoxy group and an ethylenically unsaturated double bond) decreases, whereby the molecular weight decreases and the pencil hardness increases.

The molecular weight of the component a) is 300 or less, preferably 210 or less, and more preferably 200 or less.

When the molecular weight of the a) component is 300 or less, the number of sites other than the group containing an epoxy group and an ethylenically unsaturated double bond decreases, and pencil hardness can be increased.

Further, from the viewpoint of suppressing volatilization during formation of the hard coat layer, the molecular weight of the component a) is preferably 100 or more, and more preferably 150 or more.

The a) component is not limited as long as it has a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and has a molecular weight of 300 or less, but is preferably a compound represented by the following formula (7).

Equation (7)

[Formula 2]

In formula (7), R represents a monocyclic hydrocarbon or a crosslinked hydrocarbon, L represents a single bond or a divalent linking group, and Q represents a group containing an ethylenically unsaturated double bond.

When R in formula (7) is a monocyclic hydrocarbon, it is preferably an alicyclic hydrocarbon, and among them, an alicyclic group having 4 to 10 carbon atoms is more preferable, an alicyclic group having 5 to 7 carbon atoms is more preferable, and Alicyclic groups are particularly preferred. Specifically, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group are preferable, and a cyclohexyl group is particularly preferable.

When R in formula (7) is a crosslinked hydrocarbon, bicyclic crosslinking (bicyclo ring) and tricyclic crosslinking (tricyclo ring) are preferable, and crosslinked hydrocarbons having 5 to 20 carbon atoms are exemplified. , Isobornyl group, tricyclodecyl group, dicyclopentenyl group, dicyclopentanyl group, tricyclopentenyl group, and tricyclopentanyl group, adamantyl group, lower alkyl group substituted adamantyl group, and the like.

When L represents a divalent linking group, a divalent aliphatic hydrocarbon group is preferable. As a divalent aliphatic hydrocarbon group, 1-6 are preferable, as for carbon number, 1-3 are more preferable, and 1 is more preferable. As the divalent aliphatic hydrocarbon group, a linear, branched or cyclic alkylene group is preferable, a linear or branched alkylene group is more preferable, and a linear alkylene group is more preferable.

Examples of Q include polymerizable functional groups such as (meth)acryloyl group, vinyl group, styryl group, and allyl group, and among them, (meth)acryloyl group and -C(O)OCH=CH ₂ are preferable. And particularly preferably a (meth)acryloyl group.

The specific compound of the component a) is not particularly limited as long as it has a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and has a molecular weight of 300 or less. The compound described in paragraph [0015], the compound represented by the following formula (1A) or (1B), 1,2-epoxy-4-vinylcyclohexane, and the like can be used.

Among them, a compound represented by the following formula (1A) or (1B) is more preferred, and a compound represented by the following formula (1A) having a low molecular weight is more preferred. In addition, the isomer of the compound represented by the following formula (1A) is also preferable. In the following formula (1A), L ₂ represents a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and 1 (i.e., a) component of carbon number is epoxycyclohexylmethyl(meth)acrylate. Thing) is more preferable from the viewpoint of improving smoothness.

By using these compounds, it is possible to achieve both high pencil hardness and excellent smoothness at a higher level.

[Formula 3]

In formula (1A), R ₁ represents a hydrogen atom or a methyl group, and L ₂ represents a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms.

[Formula 4]

In formula (1B), R ₁ represents a hydrogen atom or a methyl group, and L ₂ represents a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms.

In formulas (1A) and (1B), the _{divalent aliphatic hydrocarbon group of L 2} has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 carbon number. As the divalent aliphatic hydrocarbon group, a linear, branched or cyclic alkylene group is preferable, a linear or branched alkylene group is more preferable, and a linear alkylene group is more preferable.

The structure derived from a) is contained in 15 to 70% by mass when the total solid content of the hard coat layer is 100% by mass. The component a) is contained in 15 to 70% by mass when the total solid content of the composition for forming a hard coat layer in the present embodiment is 100% by mass. When the content of the structure derived from a) or the component a) with respect to the hard coat layer or the composition for forming a hard coat layer is 15% by mass or more, the effect of improving the smoothness of the surface is sufficiently obtained. On the other hand, when the content of the structure derived from a) or the component a) with respect to the hard coat layer or the composition for forming a hard coat layer is 70% by mass or less, the surface hardness can be sufficiently increased.

The structure derived from a) is preferably contained in 18 to 50% by mass, and more preferably contained in 22 to 40% by mass, when the total solid content of the hard coat layer is 100% by mass. The a) component is preferably contained in an amount of 18 to 50% by mass, and more preferably contained in an amount of 22 to 40% by mass when the total solid content of the composition for forming a hard coat layer in the present embodiment is 100% by mass. Do.

[b) a compound having a group containing three or more ethylenically unsaturated double bonds in the molecule]

The hard coat film according to the present embodiment contains 25 to 80 mass% of the structure derived from the following b) when the hard coat layer makes the total solid content of the hard coat layer 100 mass%.

b) A compound having a group containing three or more ethylenically unsaturated double bonds in the molecule.

In addition, the hard coat layer is formed by curing a composition for forming a hard coat layer comprising at least a), b), c) and d), and the composition for forming a hard coat layer is the entire composition for forming a hard coat layer. When the solid content is 100% by mass, it is preferable to contain 25 to 80% by mass of b).

The compound which has a group containing 3 or more ethylenically unsaturated double bonds in a molecule|numerator b) contained in the composition for hard coat layer formation in this embodiment is demonstrated. b) A compound having a group containing three or more ethylenically unsaturated double bonds in the molecule is also referred to as "b) component".

The component b) can exhibit high hardness by having a group containing three or more ethylenically unsaturated double bonds in the molecule.

The b) component may have a group containing 3 or more and 20 or less ethylenically unsaturated double bonds in the molecule.

Examples of the b) component include esters of polyhydric alcohols and (meth)acrylic acid, vinylbenzene and derivatives thereof, vinylsulfone, and (meth)acrylamide. Among them, from the viewpoint of hardness, a compound having three or more (meth)acryloyl groups is preferable, and an acrylate compound that forms a cured product of high hardness widely used in the present industry is mentioned. As such a compound, a compound which is an ester of a polyhydric alcohol and (meth)acrylic acid and has a group containing three or more ethylenically unsaturated double bonds in the molecule is exemplified. For example, (di)pentaerythritol tetra(meth)acrylate, (di)pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropanetri (Meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO-modified phosphoric acid tri(meth)acrylate, trimethylolethanetri(meth)acrylate, ditrimethylolpropanetetra(meth) )Acrylate, dipentaerythritol tetra(meth)acrylate, (di)pentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, pentaerythritol hexa(meth)acrylate, 1 ,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate, caprolactone modified tris (acryloxyethyl) isocyanurate, tripentaerythritol triacrylate, tri Pentaerythritol hexatriacrylate, 1,2,4-cyclohexanetetra(meth)acrylate, pentaglycerol triacrylate, etc. are mentioned.

Also preferred are resins (oligomers or prepolymers) having three or more (meth)acryloyl groups, polyfunctional (meth)acrylates having three or more (meth)acryloyl groups, and urethane (meth)acrylate. .

Examples of resins (oligomers or prepolymers) having three or more (meth)acryloyl groups include polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, Oligomers or prepolymers, such as polyfunctional compounds such as polybutadiene resin, polythiol polyene resin, and polyhydric alcohol, may also be mentioned.

As specific examples of the polyfunctional (meth)acrylate having three or more (meth)acryloyl groups, exemplary compounds shown in paragraph 0096 of JP 2007-256844 A can be given.

Specific compounds of polyfunctional acrylate compounds having three or more (meth)acryloyl groups include KAYARAD DPHA, DPHA-2C, PET-30, TMPTA, TPA-320, TPA-330 manufactured by Nippon Kayaku Co., Ltd. , RP-1040, T-1420, D-310, DPCA-20, DPCA-30, DPCA-60, GPO-303, and polyols such as V#400 and V#36095D manufactured by Yuki Chemical Industries, Osaka ( The ester product of meth)acrylic acid is mentioned. In addition, SIKO UV-1400B, UV-1700B, UV-6300B, UV-7550B, UV-7600B, UV-7605B, UV-7610B, UV-7620EA, UV-7630B, UV-7640B, UV-6630B, UV-7000B, UV-7510B, UV-7461TE, UV-3000B, UV-3200B, UV-3210EA, UV-3310EA, UV-3310B, UV-3500BA, UV-3520TL, UV-3700B, UV-6100B, UV-6640B, UV- 2000B, UV-2010B, UV-2250EA, UV-2750B (manufactured by Nippon Kosei Chemical Co., Ltd.), UL-503LN (manufactured by Kyoeisha Chemical Co., Ltd.), Unidic 17-806, 17-813, V -4030, V-4000BA (manufactured by DIC Corporation), EB-1290K, EB-220, EB-5129, EB-1830, EB-4358 (manufactured by Daicel UCB), Hicorp AU-2010, AU -2020 (manufactured by Tokushiki Co., Ltd.), Aronix M-1960 (manufactured by Toa Kosei Co., Ltd.), 3 sensory functions such as Art Resin UN-3320HA, UN-3320HC, UN-3320HS, UN-904, HDP-4T, etc. The above urethane acrylate compound, Aronix M-8100, M-8030, M-9050 (manufactured by Toa Kosei Co., Ltd.), and KBM-8307 (manufactured by Daicel Cytec Co., Ltd.) of trifunctional or higher polyester compounds, etc. It can be used suitably.

In addition, the component b) may be composed of a single compound or may be used in combination of a plurality of compounds.

The structure derived from b) is contained in 25 to 80% by mass when the total solid content of the hard coat layer is 100% by mass.

The component b) is contained in 25 to 80% by mass when the total solid content of the composition for forming a hard coat layer in the present embodiment is 100% by mass. If the content of the structure derived from b) or the component b) with respect to the hard coat layer or the composition for forming a hard coat layer is 25% by mass or more, sufficient hardness can be obtained. On the other hand, when the content of the structure derived from b) or the component b) is 80% by mass or less with respect to the hard coat layer or the composition for forming a hard coat layer, the structure derived from a) or the content of the component a) decreases, Smoothness is sufficient.

The structure derived from b) is preferably contained in an amount of 40 to 75% by mass, and more preferably contained in an amount of 60 to 75% by mass when the total solid content of the hard coat layer is 100% by mass. The b) component is preferably contained in an amount of 40 to 75% by mass, and more preferably contained in an amount of 60 to 75% by mass, when the total solid content of the composition for forming a hard coat layer in the present embodiment is 100% by mass. Do.

[Other curable compounds]

The composition for forming a hard coat layer may contain other curable compounds (hereinafter also referred to as "other curable compounds") other than the components a) and b). As other curable compounds, various compounds having a polymerizable group that can be cured (polymerized) by curing treatment can be used. Examples of the polymerizable group include a polymerizable group capable of polymerization reaction by irradiation of light, electron beam, or radiation, and a polymerizable group capable of polymerization reaction by heating, and a photopolymerizable group is preferable. In addition, another curable compound may be a monomer, oligomer, or prepolymer.

Specific examples of the polymerizable group include a ring-opening polymerization type polymerizable group such as an epoxy group such as a (meth)acryloyl group, a vinyl group, a styryl group, and a polymerizable unsaturated group such as an allyl group. Among them, a (meth)acryloyl group is preferable from the viewpoint of curability and the like.

The following compounds can be illustrated as a specific example of another curable compound that may be included in the composition for forming a hard coat layer.

(Meth)acrylic acid diesters of alkylene glycol, such as neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate, and propylene glycol di(meth)acrylate; Polyoxy, such as triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate (Meth)acrylic acid diesters of alkylene glycol; (Meth)acrylic acid diesters of polyhydric alcohols such as pentaerythritol di(meth)acrylate; Ethylene oxide or propylene oxide adducts such as 2,2-bis{4-(acryloxy·diethoxy)phenyl}propane and 2,2-bis{4-(acryloxy·polypropoxy)phenyl}propane (Meth)acrylic acid diesters; Urethane (meth)acrylates; Polyester (meth)acrylates; Isocyanuric acid acrylates; Epoxy (meth)acrylates.

As urethane (meth)acrylate, for example, a hydroxyl group-containing compound such as alcohol, polyol, and/or a hydroxyl group-containing acrylate is reacted with an isocyanate, or if necessary, these reactions Urethane (meth)acrylate obtained by esterifying the polyurethane compound obtained by using (meth)acrylic acid is mentioned. As a specific example, various commercial items mentioned in paragraph 0017 of JP 2007-256844 A can be illustrated.

The composition for forming a hard coat layer may contain an epoxy-based compound having an epoxy group as a polymerizable group as another curable compound from the viewpoint of reducing curing shrinkage. As the epoxy compound, a polyfunctional epoxy compound containing two or more epoxy groups per molecule is preferable. As specific examples, JP 2004-264563, JP 2004-264564, JP 2005-37737, JP 2005-37738, JP 2005-140862, JP The epoxy-based compounds described in Patent Publication No. 2005-140862, JP 2005-140863 A, and JP 2002-322430 A may be mentioned. Further, it is also preferable to use a compound having both an epoxy group such as glycidyl (meth)acrylate and an acrylic polymerizable group.

The content of the other curable compound relative to the total solid content of the hard coat layer-forming composition is 15% by mass or less when the total solid content of the hard coat layer-forming composition is 100% by mass from the viewpoint of the hardness of the hard coat layer. It is preferable, it is more preferable that it is 10 mass% or less, it is more preferable that it is 1 mass% or less, it is more preferable that it is 0.01 mass% or less, It is especially preferable that it does not contain substantially.

[c) radical polymerization initiator]

The hard coat film according to the present embodiment contains 0.1 to 10 mass% of c) a radical polymerization initiator when the hard coat layer makes the total solid content of the hard coat layer 100% by mass.

The c) radical polymerization initiator contained in the hard coat layer or the composition for forming a hard coat layer in the present embodiment will be described. Hereinafter, c) a radical polymerization initiator is also referred to as "c) component".

The polymerization of the compound having an ethylenically unsaturated group can be carried out by irradiation of ionizing radiation or heating in the presence of a photo radical polymerization initiator or a thermal radical polymerization initiator.

Commercially available compounds can be used as the photo and thermal polymerization initiators, and they are "latest UV curing technology" (p. 159, publisher; Takaus Kazuhiro, publishing house; Kijutsu Joho Kyokai, published in 1991), or It is listed in the catalog of Chiba Specialty Chemicals Co., Ltd.

c) As a component, specifically, an alkylphenone-based photoinitiator (Irgacure651, Irgacure184, DAROCURE1173, Irgacure2959, Irgacure127, DAROCURE MBF, Irgacure907, Irgacure369, Irgacure379EG), acylphosphine oxide-based photopolymerization initiator (Irgacure819, Irgacure819), its Others (Irgacure784, Irgacure OXE01, Irgacure OXE02, Irgacure754) and the like can be used.

c) The amount of the component added is in the range of 0.1 to 10% by mass, in the case where the total solid content of the hard coat layer or the composition for forming a hard coat layer in the present embodiment is 100% by mass, and 1 to 5% by mass is It is preferable, and 2-4 mass% is more preferable. c) When the amount of the component added is 0.1% by mass or more when the total solid content of the hard coat layer or the composition for forming a hard coat layer is 100% by mass, polymerization proceeds sufficiently, and the pencil hardness of the hard coat layer can be increased. . On the other hand, when the addition amount of the component c) is 10% by mass or less when the total solid content of the hard coat layer or the composition for forming a hard coat layer is 100% by mass, UV light reaches the inside of the film, and the pencil hardness of the hard coat layer Can increase. These c) radical initiators may be used alone or may be used in combination of a plurality of types.

[d) Cationic polymerization initiator]

The hard coat film according to the present embodiment contains d) 0.1 to 10 mass% of a cationic polymerization initiator when the hard coat layer makes the total solid content of the hard coat layer 100 mass%.

The d) cationic polymerization initiator contained in the hard coat layer or the composition for forming a hard coat layer in the present embodiment will be described. Hereinafter, d) a cationic polymerization initiator is also called "d) component."

Examples of the component d) include known compounds and mixtures thereof, such as a photoinitiator for photocationic polymerization, a photochromic agent for pigments, a photochromic agent, or a known acid generator used in microresist and the like.

For example, an onium compound, an organic halogen compound, and a disulfone compound are mentioned. Specific examples of these organic halogen compounds and disulfone compounds include the same compounds as those described for the compounds generating radicals.

Examples of the onium compound include diazonium salts, ammonium salts, iminium salts, phosphonium salts, iodonium salts, sulfonium salts, alsonium salts, selenonium salts, etc., for example, paragraph No. of JP 2002-29162 [ The compounds described in [0058] to [0059], etc. may be mentioned.

In the present embodiment, particularly suitably used cationic polymerization initiators include onium salts, and diazonium salts, iodonium salts, sulfonium salts, and iminium salts include photosensitivity at the initiation of photopolymerization, and material stability of the compound. It is preferable from a point, and an iodonium salt is most preferable especially from a viewpoint of light resistance.

In this embodiment, as a specific example of an onium salt that can be used suitably, for example, the amylated sulfonium salt described in paragraph number [0035] of JP-A-9-268205, paragraphs of JP-A-2000-71366 Diaryliodonium salts or triarylsulfonium salts described in numbers [0010] to [0011], sulfonium salts of thiobenzoic acid S-phenyl esters described in paragraph number [0017] of Japanese Laid-Open Patent Publication 2001-288205, Japanese Patent Application Laid-Open The onium salts described in paragraphs [0030] to [0033] of Publication 2001-133696 A may be mentioned.

As another example, the organometallic/organic halides described in paragraphs [0059] to [0062] of Japanese Patent Application Laid-Open No. 2002-29162, a photoacid generator having an o-nitrobenzyl-type protecting group, photo-decomposition to generate sulfonic acid Compounds, such as a compound (iminosulfonate, etc.), are mentioned.

Specific compounds of the iodonium salt-based cationic polymerization initiator include B2380 (manufactured by Tokyo Kasei), BBI-102 (manufactured by Midori Chemical), WPI-113 (manufactured by Wako Junyaku Kogyo), and WPI-124 (manufactured by Wako Junyaku Kogyo). , WPI-169 (made by Wako Junyaku High School), WPI-170 (made by Wako Junyaku High School), and DTBPI-PFBS (made by Toyo Kosei Chemical) can be used.

Furthermore, as a preferable example of the cationic polymerization initiator of an iodonium salt system, the following compounds FK-1 and FK-2 are mentioned.

Photocationic polymerization initiator (iodonium salt compound) FK-1

[Formula 5]

Photocationic polymerization initiator (iodonium salt compound) FK-2

[Formula 6]

As d) component, only 1 type may be used and 2 or more types may be used together.

The d) component is added in the range of 0.1 to 10% by mass, preferably 0.5 to 3.0, when the total solid content of the hard coat layer or the composition for forming a hard coat layer in the present embodiment is 100% by mass. It can be added in a mass% ratio. It is preferable that the addition amount is in the above range from the stability of the coating liquid, polymerization reactivity, and the like.

[e) Inorganic particles having reactivity of an epoxy group or a group containing an ethylenically unsaturated double bond]

It is preferable to add e) inorganic particles having reactivity of an epoxy group or a group containing an ethylenically unsaturated double bond to the hard coat layer or the composition for forming a hard coat layer in the present embodiment. Hereinafter, e) inorganic particles having reactivity of an epoxy group or a group containing an ethylenically unsaturated double bond are also referred to as "e) component".

Since the amount of curing shrinkage of the hard coat layer (cured layer) can be reduced by adding inorganic particles, smoothness can be improved. Further, it is possible to improve the pencil hardness by using inorganic particles having reactivity of an epoxy group or a group containing an ethylenically unsaturated double bond.

Examples of the inorganic particles include silica particles, titanium dioxide particles, zirconium oxide particles, and aluminum oxide particles. Among them, e) it is preferable that the inorganic particles having reactivity of the epoxy group or the group containing an ethylenically unsaturated double bond are silica particles.

In general, since inorganic particles have low affinity with organic components such as polyfunctional vinyl monomers, only mixing can form aggregates, or the hard coat layer after curing may become more likely to crack. Therefore, in the component e), since the affinity between the inorganic particles and the organic component is increased, the surface of the inorganic particles is preferably treated with a surface modifier containing an organic segment.

The surface modifier is preferably a surface modifier having a functional group capable of forming a bond with an inorganic particle or adsorbing to the inorganic particle, and a functional group having high affinity with an organic component in the same molecule. As a surface modifier having a functional group capable of bonding or adsorbing to inorganic particles, metal alkoxide surface modifiers such as silane, aluminum, titanium, and zirconium, or surfaces having anionic groups such as phosphoric acid, sulfuric acid, sulfonic acid, and carboxylic acid groups Modifiers are preferred. In addition, the functional group having high affinity with the organic component may be a functional group that is only a combination of an organic component and hydrophobicity, but a functional group capable of chemically bonding with the organic component is preferred, and in particular, a group containing an ethylenically unsaturated double bond. Or a ring-opening polymerizable group is preferable.

In this embodiment, a preferable surface modifier for inorganic particles is a curable resin having a metal alkoxide or a group containing an anionic group and an ethylenically unsaturated double bond, or a ring-opening polymerizable group in the same molecule. By chemically bonding with the organic component, the crosslinking density of the hard coat layer increases, and the pencil hardness can be increased.

Representative examples of these surface modifiers include coupling agents containing the following unsaturated double bonds, organic curable resins containing a phosphoric acid group, organic curable resins containing a sulfuric acid group, and organic curable resins containing a carboxylic acid group.

S-1 H ₂ C=C(X)COOC ₃ H ₆ Si(OCH ₃ ) ₃

S-2 H ₂ C=C(X)COOC ₂ H ₄ OTi(OC ₂ H ₅ ) ₃

S-3 H ₂ C=C(X)COOC ₂ H ₄ OCOC ₅ H ₁₀ OPO(OH) ₂

S-4 (H ₂ C=C(X)COOC ₂ H ₄ OCOC ₅ H ₁₀ O) ₂ POOH

S-5 H ₂ C=C(X)COOC ₂ H ₄ OSO ₃ H

S-6 H ₂ C=C(X)COO(C ₅ H ₁₀ COO) ₂ H

S-7 H ₂ C=C(X)COOC ₅ H ₁₀ COOH

S-8 CH ₂ CH(O)CH ₂ OC ₃ H ₆ Si(OCH ₃ ) ₃

(X represents a hydrogen atom or CH ₃ )

It is preferable that the surface modification of these inorganic particles is performed in a solution. When the inorganic particles are mechanically finely dispersed, a surface modifier is present together, or after finely dispersing the inorganic particles, a surface modifier is added and stirred, or further, surface modification is performed before finely dispersing the inorganic particles ( If necessary, heating or pH change after heating or drying), and then fine dispersion may be employed. As a solution for dissolving the surface modifier, an organic solvent having a large polarity is preferable. Specifically, well-known solvents, such as alcohol, ketone, and ester, are mentioned.

The addition amount of the component e) is 5 to 40 mass when the total solid content of the composition for forming the hard coat layer or the hard coat layer in the present embodiment is 100% by mass in consideration of the balance between the hardness and brittleness of the coating film. % Is preferable, and 10-30 mass% is more preferable.

The size (average primary particle diameter) of the inorganic particles is preferably 10 nm to 100 nm, more preferably 10 to 60 nm. The average particle diameter of the particles can be obtained from an electron micrograph. When the particle size of the inorganic particles is equal to or greater than the lower limit, the effect of improving the hardness is obtained, and when it is equal to or less than the upper limit, an increase in haze can be suppressed.

The shape of the inorganic particles is not limited to a spherical shape or a non-spherical shape, but a non-spherical shape in which 2 to 10 inorganic particles are connected is preferable from the viewpoint of imparting hardness. It is estimated that a strong particle network structure is formed and the hardness is improved by using inorganic particles in which several are connected in a chain shape.

Specific examples of inorganic particles include ELECOM V-8802 (Spherical silica particles manufactured by Nikki Corporation with an average primary particle diameter of 12 nm), ELECOM V-8803 (release silica particles manufactured by Nikki Corporation), and MiBK-SD (Nissan Kaga). Spherical silica particles with an average primary particle diameter of 10 to 20 nm, manufactured by Ku Kogyo Co., Ltd.), MEK-AC-2140Z (spherical silica particles with an average primary particle diameter of 10 to 20 nm, manufactured by Nissan Chemical Co., Ltd.), MEK- AC-4130 (Spherical silica particles with an average primary particle diameter of 40 to 50 nm manufactured by Nissan Chemical Industry Co., Ltd.), MiBK-SD-L (Spherical particles with an average primary particle diameter of 40 to 50 nm manufactured by Nissan Chemical Industry Co., Ltd.) Silica particles), MEK-AC-5140Z (spherical silica particles having an average primary particle diameter of 70 to 100 nm, manufactured by Nissan Chemical Industries, Ltd.), and the like. Among them, ELECOM V-8803 of a mold release is preferable from the viewpoint of imparting surface hardness.

[f) Polyester urethane]

It is preferable from the viewpoint of enhancing brittleness that f) contains polyester urethane in the hard coat layer or the composition for forming a hard coat layer in the present embodiment. Hereinafter, f) polyester urethane is also referred to as "f) component".

The polyester urethane is a polymer containing an ester bond and a urethane bond (-O-CO-NH-) in one molecule.

f) The polyester urethane is preferably a polyester urethane having a tensile strength of 25 MPa or more and a tensile elongation of 200% or more. It is considered that polyester urethane having a tensile strength of 25 MPa or more and a tensile elongation of 200% or more can contribute to increase the hardness of the hard coat layer and to impart moderate flexibility. It is estimated that this contributes to the increase in hardness and brittleness of the hard coat layer.

In addition, if the polyester urethane content is 1 part by mass or more with respect to 100 parts by mass of the total solid content of the hard coat layer or the composition for forming a hard coat layer, the above effect by the addition of polyester urethane can be sufficiently obtained, If it is 10 parts by mass or less, the hardness of the cured layer can be maintained. Therefore, the polyester urethane content with respect to 100 parts by mass of the total solid content of the hard coat layer or the composition for forming a hard coat layer is in the range of 1 to 10 parts by mass. From the viewpoint of improving brittleness and suppressing the decrease in transparency, it is more preferably 2 parts by mass or more, and more preferably 8 parts by mass or less from the viewpoint of maintaining the hardness of the hard coat layer.

The use of polyester urethane exhibiting the above tensile strength and tensile elongation as polyester urethane contributes to achieving high hardness and improved brittleness by imparting appropriate flexibility to the hard coat layer. More preferably, the tensile strength is 40 MPa or more, and still more preferably 50 MPa or more. In addition, the tensile strength is preferably 70 MPa or less from the viewpoint of compatibility stability in the composition for forming a hard coat layer. On the other hand, the tensile elongation is preferably 450% or more, and more preferably 600% or more. Moreover, from the viewpoint of securing pencil hardness, which is one of the indexes of film hardness, the tensile elongation is preferably 1000% or less. About the measuring method of pencil hardness, an Example is mentioned later. The tensile strength and tensile elongation of polyester urethane are values measured using a tensile strength tester according to JIS K 6251.

Polyester urethane can be obtained by polymerization of a monomer component containing at least a diol, a dicarboxylic acid, and a diisocyanate. As these three types of monomers, polyesters each having a hydroxyl group (-OH), a carboxyl group (-COOH), and an isocyanate group (-NCO) at both ends of a hydrocarbon group having a non-branched structure Urethane is preferred.

The hydrocarbon group having a non-branched structure is preferably an alkylene group, an alkenylene group, an alkynylene group, an arylene group, or a combination thereof.

It is preferable that an alkylene group, an alkenylene group, and an alkynylene group have a linear structure.

When the hydrocarbon group is an alkylene group, an alkenylene group, or an alkynylene group, the number of carbon atoms is preferably 1 to 8, more preferably 2 to 6, and still more preferably 2 to 4.

The arylene group may have an alkyl group having 1 to 8 carbon atoms as a substituent.

As an arylene group, it is preferable that it is a phenylene group or a naphthylene group, it is more preferable that it is a phenylene group, and it is more preferable that it is a p-phenylene group.

Particularly as the hydrocarbon group, the alkylene group, the arylene group, or a combination thereof is preferable.

As a diol used as a monomer of polyester urethane, ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol , 1,4-cyclohexanedimethanol and 1,5-pentanediol are preferred.

As the dicarboxylic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, oxalic acid and malonic acid are preferable.

As diisocyanate, ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, m-xylylene diisocyanate, p- Phenylene diisocyanate, tolylene diisocyanate, p,p'-diphenylmethane diisocyanate and 1,5-naphthylene diisocyanate are preferred.

The number average molecular weight (Mn) of polyester urethane is preferably 5000 or more from the viewpoint of affinity with inorganic particles, more preferably 10000 or more, and preferably 50000 or less from the viewpoint of compatibility with a curable compound.

Moreover, in one aspect, polyester urethane may have a reactive group. As a reactive group, Preferably it is a polymerizable unsaturated group. For a specific example, it is as described with respect to the functional group which an inorganic particle may have first.

As the polyester urethane described above, polyester urethane synthesized by a known method may be used, or a commercial item may be used. As a commercial item, Viron (registered trademark) series (brand name): manufactured by Toyobo Corporation, etc. are mentioned, and Viron UR-2300, Viron UR-3200, Viron UR-3210, Viron UR-3260, Viron UR-5537, Viron UR-8300, Viron UR-8700, and the like can be preferably used.

[g) antifouling agent]

In the hard coat layer or the composition for forming a hard coat layer in the present embodiment, g) containing an antifouling agent is preferable because adhesion of fingerprints and dirt is reduced, and adhered dirt can be easily wiped off. Moreover, it is also preferable from a viewpoint of improving the scratch resistance by improving the slipperiness of the surface. Hereinafter, g) antifouling agent is also called "g) component."

In the hard coat film according to the present embodiment, g) the antifouling agent contains a fluorinated compound, the fluorinated compound has a perfluoropolyether group and a polymerizable unsaturated group, and has a plurality of polymerizable unsaturated groups in one molecule. It is desirable.

The g) antifouling agent that can be used in the present embodiment will be described.

[Fluorine-containing compound having a polymerizable unsaturated group]

g) The antifouling agent contains a fluorinated compound, and the fluorinated compound has a perfluoropolyether group and a polymerizable unsaturated group, and a compound having a plurality of polymerizable unsaturated groups in one molecule (hereinafter referred to as "fluorinated antifouling agent Also referred to as ") will be described.

It is preferable that the fluorinated antifouling agent is a fluorine-based compound containing a structure represented by the following formula (F).

Formula (F): (Rf)-[(W)-(R _A ) _n ] _m

In the formula, Rf represents a (per)fluoroalkyl group or a (per)fluoropolyether group, W represents a linking group, and R _A represents a polymerizable unsaturated group. n represents the integer of 1-3. m represents the integer of 1-3.

It is considered that the fluorinated antifouling agent has the following effects (1) to (3) by having a polymerizable unsaturated group.

(1) Since solubility in organic solvents and compatibility with compounds having an unsaturated double bond are increased, it is considered that the antifouling agent can be uniformly localized on the surface without forming aggregates. In addition, it is possible to prevent the occurrence of defects due to aggregates.

(2) Even if the fluorinated antifouling agent is localized on the surface, a covalent bond can be formed between the fluorinated antifouling agents or by photopolymerization reaction with a compound having an unsaturated double bond. It can prevent deterioration of antifouling properties.

(3) It is possible to prevent the deterioration of the appearance and loss of the antifouling property due to the precipitation of the antifouling agent by bleeding out.

In formula (F), R _A represents a polymerizable unsaturated group. The polymerizable unsaturated group is not particularly limited as long as it is a group capable of causing a radical polymerization reaction by irradiating with an active energy ray such as ultraviolet rays or electron beams, and a (meth)acryloyl group, a (meth)acryloyloxy group, a vinyl group, an allyl group, etc. Examples include, and a (meth)acryloyl group, a (meth)acryloyloxy group, and a group in which an arbitrary hydrogen atom in these groups is substituted for a fluorine atom is preferably used.

As a specific example of the polymerizable unsaturated group, a group having a structure shown below is preferable.

[Formula 7]

In formula (F), Rf represents a (per)fluoroalkyl group or a (per)fluoropolyether group.

Herein, the (per)fluoroalkyl group represents at least one of a fluoroalkyl group and a perfluoroalkyl group, and the (per)fluoropolyether group is at least one of a fluoropolyether group and a perfluoropolyether group. Represents. From the viewpoint of antifouling properties, it is preferable that the fluorine content rate in Rf is high.

It is preferable that the (per)fluoroalkyl group is a C1-C20 group, More preferably, it is a C1-C10 group.

(Per) fluoroalkyl group is a straight chain (e.g. -CF ₂ CF ₃ , -CH ₂ (CF ₂ ) ₄ H, -CH ₂ (CF ₂ ) ₈ CF ₃ , -CH ₂ CH ₂ (CF ₂ ) ₄ H Etc.), branch structure (e.g. CH(CF ₃ ) ₂ , CH ₂ CF(CF ₃ ) ₂ , CH(CH ₃ ) CF ₂ CF ₃ , CH(CH ₃ )(CF ₂ ) ₅ CF ₂ H Etc.), or an alicyclic structure (preferably a 5-membered ring or a 6-membered ring, such as a perfluorocyclohexyl group, a perfluorocyclopentyl group, or an alkyl group substituted with these).

The (per)fluoropolyether group refers to a case where the (per)fluoroalkyl group has an ether bond, and may be monovalent or a divalent or higher contribution. Examples of the fluoropolyether group include -CH ₂ OCH ₂ CF ₂ CF ₃ , -CH ₂ CH ₂ OCH ₂ C ₄ F ₈ H, -CH ₂ CH ₂ OCH ₂ CH ₂ C ₈ F ₁₇ , -CH ₂ CH ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ H, a fluorocycloalkyl group having 4 to 20 carbon atoms having 4 or more fluorine atoms, and the like. In addition, examples of the perfluoropolyether group include -(CF ₂ O) _p -(CF ₂ CF ₂ O) _q -, -[CF(CF ₃ )CF ₂ O] _p -[CF ₂ (CF ₃ )]-, -(CF ₂ CF ₂ CF ₂ O) _p -, -(CF ₂ CF ₂ O) _p -.

The total sum of p and q is preferably 1 to 83, more preferably 1 to 43, and most preferably 5 to 23.

It is particularly preferable that the fluorinated antifouling agent has a perfluoropolyether group represented by -(CF ₂ O) _p -(CF ₂ CF ₂ O) _{q-from the viewpoint of excellent antifouling properties.}

Each of p and q independently represents an integer of 0 to 20. However, p+q is an integer of 1 or more.

From the viewpoint that the effects shown in (1) to (3) described above are more remarkably obtained, it is preferable that the fluorinated antifouling agent has a perfluoropolyether group and a plurality of polymerizable unsaturated groups per molecule.

In formula (F), W represents a connecting group. Examples of W include an alkylene group, an arylene group, a heteroalkylene group, or a linking group in which these groups are combined. These linking groups may further have an oxy group, a carbonyl group, a carbonyloxy group, a carbonyl imino group, a sulfonamide group, or the like, or a functional group in which these groups are combined.

As W, preferably an ethylene group, more preferably an ethylene group bonded with a carbonyl imino group.

From the viewpoint of obtaining the effects shown in the above (1) to (3) more remarkably, in the formula (F), the product of n and m (n×m) is preferably 2 or more, and more preferably 4 or more. Do.

In the formula (F), when both n and m are 1, the following formulas (F-1) to (F-3) are exemplified as specific examples of the following preferred embodiments.

Equation (F-1):

^{_{Rf 2 (CF 2 CF 2)}} p R '2 CH 2 CH 2 R 2 OCOCR 1 = CH 2

In formula (F-1), Rf ² represents a fluorine atom or a fluoroalkyl group having 1 to 10 carbon atoms, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a single bond or an alkylene group. , R ^'2 represents a single bond or a divalent linking group, p is an integer that represents the degree of polymerization, the degree of polymerization p is greater than or equal to k (k is an integer greater than or equal to 3).

When R ^'2 represents a divalent linking group, examples of the divalent linking group, it can be given the same linkage group and W.

Examples of the telomer-type acrylate containing a fluorine atom in the formula (F-1) include partial or fully fluorinated alkyl ester derivatives of (meth)acrylic acid.

Although specific examples of the compound represented by formula (F-1) are shown below, it is not limited to these compounds.

[Formula 8]

^{When the compound represented by the above formula (F-1) uses telomerization during synthesis, the group Rf 2} (CF ₂ ) of the formula (F-1) depends on the conditions of telomerization and separation of the reaction mixture. ^{_{CF 2) p R '2 CH}} 2 CH there is a case where a plurality of the fluorinated (meth) acrylic acid ester such as ₂ R ² p O-, each k, k + 1, k + 2, ··· in.

Equation (F-2):

F(CF ₂ ) _q -CH ₂ -CHX-CH ₂ Y

In formula (F-2), q is an integer of 1 to 20, X and Y are each independently either a (meth)acryloyloxy group or a hydroxyl group, and at least one is a (meth)acryloyloxy group.

The fluorinated (meth)acrylic acid ester represented by formula (F-2) has a fluoroalkyl group _{having 1 to 20 carbon atoms having a trifluoromethyl group (CF 3} -) at the terminal, and this fluorinated (meth)acrylic acid ester Even in a small amount, trifluoromethyl groups are effectively oriented on the surface.

From the antifouling property and ease of manufacture, 6-20 are preferable and, as for q, 8-10 are more preferable. The fluorinated (meth)acrylic acid ester having a fluoroalkyl group having 8 to 10 carbon atoms has excellent water and oil repellency even compared to the fluorinated (meth)acrylic acid ester having a fluoroalkyl group of other chain lengths. Because it expresses, it is excellent in antifouling property.

As a fluorinated (meth)acrylic acid ester represented by formula (F-2), specifically, 1-(meth)acryloyloxy-2-hydroxy-4,4,5,5,6,6,7,7 ,8,8,9,9,10,10,11,11,12,12,13,13,13-heneicosafluorotridecaine, 2-(meth)acryloyloxy-1-hydroxy -4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,13-Heneicosafluorotride Kane and 1,2-bis(meth)acryloyloxy-4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12 ,13,13,13-heneicosafluorotridecane, etc. are mentioned. In this embodiment, 1-acryloyloxy-2-hydroxy-4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11, 12,12,13,13,13-Heneicosafluorotridecane is preferred.

Equation (F-3):

F(CF ₂ ) _r O(CF ₂ CF ₂ O) _s CF ₂ CH ₂ OCOCR ³ =CH ₂

In formula (F-3), R ³ is a hydrogen atom or a methyl group, s is an integer of 1 to 20, and r represents an integer of 1 to 4.

The fluorine atom-containing monofunctional (meth)acrylate represented by the above formula (F-3) can be obtained by reacting a fluorine atom-containing alcohol compound represented by the following formula (FG-3) with a (meth)acrylic acid halide.

Equation (FG-3):

F(CF ₂ ) _r O(CF ₂ CF ₂ O) _s CF ₂ CH ₂ OH

In Formula (FG-3), s is an integer of 1-20, and r represents an integer of 1-4.

Specific examples of the fluorine atom-containing alcohol compound represented by formula (FG-3) include, for example, 1H,1H-perfluoro-3,6-dioxaheptan-1-ol, 1H,1H-perfluoro-3, 6-dioxaoctan-1-ol, 1H,1H-perfluoro-3,6-dioxadecan-1-ol, 1H,1H-perfluoro-3,6,9-trioxadecan-1- Ol, 1H,1H-perfluoro-3,6,9-trioxaundecan-1-ol, 1H,1H-perfluoro-3,6,9-trioxatridecan-1-ol, 1H, 1H-perfluoro-3,6,9,12-tetraoxatridecan-1-ol, 1H,1H-perfluoro-3,6,9,12-tetraoxatetradecan-1-ol, 1H, 1H-perfluoro-3,6,9,12-tetraoxahexadecan-1-ol, 1H,1H-perfluoro-3,6,9,12,15-pentaoxahexadecan-1-ol, 1H,1H-perfluoro-3,6,9,12,15-pentaoxaheptadecan-1-ol, 1H,1H-perfluoro-3,6,9,12,15-pentaoxanonadecan- 1-ol, 1H,1H-perfluoro-3,6,9,12,15,18-hexaoxaicosan-1-ol, 1H,1H-perfluoro-3,6,9,12,15 ,18-hexaoxadocosan-1-ol, 1H,1H-perfluoro-3,6,9,12,15,18,21-heptaoxatricosan-1-ol, 1H,1H-perfluoro -3,6,9,12,15,18,21-heptaoxapentacosan-1-ol, etc. are mentioned.

These are available on the market, and specific examples thereof include, for example, 1H,1H-perfluoro-3,6-dioxaheptan-1-ol (trade name "C5GOL", manufactured by Exfluor), 1H,1H-purple Luoro-3,6,9-trioxadecan-1-ol (trade name "C7GOL", manufactured by Exfluor), 1H,1H-perfluoro-3,6-dioxadecan-1-ol (trade name "C8GOL" ", manufactured by Exfluor), 1H,1H-perfluoro-3,6,9-trioxatridecan-1-ol (trade name "C10GOL", manufactured by Exfluor), 1H,1H-perfluoro-3, 6,9,12-tetraoxahexadecan-1-ol (trade name "C12GOL", manufactured by Exfluor Corporation), etc. are mentioned.

In this embodiment, it is preferable to use 1H,1H-perfluoro-3,6,9,12-tetraoxatridecan-1-ol.

Moreover, as (meth)acrylic acid halide reacted with the fluorine atom-containing alcohol compound represented by Formula (FG-3), (meth)acrylic acid fluoride, (meth)acrylic acid chloride, (meth)acrylic acid bromide, (meth)acrylic acid ioda Droid is mentioned. From the viewpoint of availability, etc., (meth)acrylic acid chloride is preferred.

Although a preferable specific example of the compound represented by Formula (F-3) is shown below, it is not limited to these. In addition, a preferred specific example represented by Formula (F-3) is also described in JP 2007-264221 A.

(b-1): F ₉ C ₄ OC ₂ F ₄ OC ₂ F ₄ OCF ₂ CH ₂ OCOCH=CH ₂

(b-2): F ₉ C ₄ OC ₂ F ₄ OC ₂ F ₄ OCF ₂ CH ₂ OCOC(CH ₃ )=CH ₂

Further, apart from the compound represented by the formula (F-3), a compound represented by the following formula (F-3A) can also be preferably used.

Equation (F-3A):

Rf ³ -[(O) _c (O=C) _b (CX ⁴ X ⁵ ) _a -CX ³ =CX ¹ X ² ]

(Wherein, X ¹ and X ² each independently represent H or F, X ³ represents H, F, CH ₃ or CF ₃ , and X ⁴ and X ⁵ are each independently H, F, or CF ₃ represents, a, b, and c each independently represent 0 or 1, and Rf ³ represents a fluorinated alkyl group containing an ether bond having 18 to 200 carbon atoms), in Rf ³ group,

Formula (FG-3A):

-(CX ⁶ ₂ CF ₂ CF ₂ O)-

(In the formula, X ⁶ is a fluorinated unsaturated compound having 6 or more repeating units represented by F or H).

As an example of the fluorinated polyether compound represented by formula (F-3A),

(c-1) Rf ³ -[(O)(O=C) _b -CX ³ =CX ¹ X ² ]

(c-2) Rf ³ -[(O)(O=C)-CX ³ =CX ¹ X ² ]

(c-3) Rf ³ -[(O) _c (O=C)-CF=CH ₂ ]

And the like, and as the polymerizable unsaturated group of the fluorinated polyether compound, a group having the following structure is preferable. The definition of each symbol in (c-1) to (c-3) is synonymous with Formula (F-3A).

[Formula 9]

Moreover, the fluorinated polyether compound represented by formula (F-3A) may have a plurality of polymerizable unsaturated groups,

[Formula 10]

Structures such as the like are preferably mentioned. In the present embodiment, a compound having a structure of -O(C=O)CF=CH ₂ is particularly preferred because the polymerization (curing) reactivity is particularly high and a cured product can be efficiently obtained.

Formula Rf ³ groups according also to the emitter compound in fluoride poly represented by (F-3A) formula (FG-3A) also important to include the six or more Rf ³ to teoswae the fluorine polyester repeat units and, accordingly, the Can impart antifouling properties.

In more detail, a mixture containing a compound having 6 or more repeating units of the fluorinated polyether chain may be used, but when used in the form of a mixture, a fluorinated unsaturated compound having less than 6 repeating units and 6 or more fluorine-containing compounds may be used. In the distribution of the unsaturated compound, it is preferable to use a mixture having the highest proportion of the fluorinated unsaturated compound having 6 or more repeating units of the polyether chain.

The number of repeating units of the fluorinated polyether chain of the formula (FG-3A) is preferably 6 or more, more preferably 10 or more, more preferably 18 or more, and particularly preferably 20 or more. Accordingly, it is possible to improve not only water repellency but also antifouling properties, in particular, removal properties for contamination including oil components. Moreover, gas permeability can also be imparted more effectively. Moreover, the fluorinated polyether ^{chain may be present at the terminal of the Rf 3} group or may be present in the middle of the chain.

The Rf ³ group is specifically,

Equation (c-4):

R ⁴ -(CX ⁶ ₂ CF ₂ CF ₂ O) _t -(R ⁵ ) _e-

(Wherein, X ⁶ is the same as formula (FG-3A), and R ⁴ is selected from a hydrogen atom, a halogen atom or an alkyl group, a fluorinated alkyl group, an alkyl group including an ether bond, and a fluorinated alkyl group including an ether bond. It is preferable that it is a structure of at least 1 type, R ⁵ is a divalent or higher organic group, t is an integer of 6 to 66, and e represents 0 or 1).

That is, it is a fluorinated organic group bonded with a reactive carbon-carbon double bond through the divalent or higher organic group R ^{5 , and further has R 4 at the terminal.}

R ⁵ may be any organic group as long as it is an organic group capable of bonding the fluorinated polyether chain of the formula (FG-3A) to a reactive carbon-carbon double bond. For example, it is selected from an alkylene group, a fluorinated alkylene group, an alkylene group containing an ether bond, and a fluorinated alkylene group containing an ether bond. Among them, a fluorinated alkylene group and a fluorinated alkylene group containing an ether bond are preferable from the viewpoint of transparency and low refractive index.

As a specific example of the fluorinated polyether compound represented by formula (F-3A), the compounds exemplified in the pamphlet of WO2003/022906 are preferably used. In this embodiment, CH ₂ =CF-COO-CH ₂ CF ₂ CF ₂ -(OCF ₂ CF ₂ CF ₂ ) ₇ -OC ₃ F ₇ can be particularly preferably used.

In formula (F), when n and m are not 1 at the same time, formulas (F-4) and (F-5) are mentioned as the following preferred embodiments.

Equation (F-4): (Rf ¹ )-[(W)-(R _A ) _n ] _m

(In formula (F-4), Rf ¹ represents a (per) fluoroalkyl group or a (per) fluoropolyether group, W represents a linking group, and R _A represents a functional group having an unsaturated double bond. n represents 1 to 3, and m represents an integer of 1 to 3, and n and m are not 1 at the same time.)

From the viewpoint of excellent water and oil repellency and excellent durability (antifouling durability) of water and oil repellency, n is preferably 2 to 3, m is 1 to 3, n is 2 to 3, m is 2 to 3 It is more preferable, and it is most preferable that n is 3 and m is 2-3.

Rf ¹ may use a monovalent to trivalent group. When Rf ¹ is monovalent, the terminal groups are (C _n F _2n+1 )-, (C _n F _2n+1 O)-, (XC _n F _2n O)-, (XC _n F _2n+1 )-( In the formula, X is hydrogen, chlorine, or bromine, and n is preferably an integer of 1 to 10). Specifically, CF ₃ O(C ₂ F ₄ O) _p CF ₂ -, C ₃ F ₇ O(CF ₂ CF ₂ CF ₂ O) _p CF ₂ CF ₂ -, C ₃ F ₇ O(CF(CF ₃ ) CF ₂ O) _p CF(CF ₃ )-, F(CF(CF ₃ )CF ₂ O) _p CF(CF ₃ )-, etc. may be preferably used.

Here, the average value of p is 0-50. It is preferably 3 to 30, more preferably 3 to 20, and most preferably 4 to 15.

When Rf ¹ is divalent, -(CF ₂ O) _q (C ₂ F ₄ O) _r CF ₂ -, -(CF ₂ ) ₃ O(C ₄ F ₈ O) _r (CF ₂ ) ₃ -,- CF ₂ O(C ₂ F ₄ O) _r CF ₂ -, -C ₂ F ₄ O(C ₃ F ₆ O) _r C ₂ F ₄ -, -CF(CF ₃ )(OCF ₂ CF(CF ₃ )) _s OC _t F _2t O(CF(CF ₃ )CF ₂ O) _r CF(CF ₃ )- and the like can be preferably used.

Here, in the formula, the average values of q, r, and s are 0-50. It is preferably 3 to 30, more preferably 3 to 20, and most preferably 4 to 15. t is an integer of 2-6.

Preferred specific examples or synthesis methods of the compound represented by formula (F-4) are described in International Publication No. 2005/113690.

Hereinafter, a compound having an average p value of 6 to 7 in F(CF(CF ₃ )CF ₂ O) _p CF(CF ₃ )- is described as "HFPO-", and -(CF(CF ₃ )CF ₂ O) In _p CF (CF ₃ )-, a compound having an average p value of 6 to 7 is described as "-HFPO-", and a specific compound of the formula (F-4) is shown, but is not limited thereto.

(d-1): HFPO-CONH-C-(CH ₂ OCOCH=CH ₂ ) ₂ CH ₂ CH ₃

(d-2): HFPO-CONH-C-(CH ₂ OCOCH=CH ₂ ) ₂ H

(d-3): HFPO-CONH-C ₃ H ₆ NHCH ₃ and 1:1 Michael addition polymer of trimethylolpropanetriacrylate

(d-4): (CH ₂ =CHCOOCH ₂ ) ₂ HC-CONH-HFPO-CONH-C-(CH ₂ OCOCH=CH ₂ ) ₂ H

(d-5): (CH ₂ =CHCOOCH ₂ ) ₃ -C-CONH-HFPO-CONH-C-(CH ₂ OCOCH=CH ₂ ) ₃

Further, as the compound represented by the formula (F-4), a compound represented by the following formula (F-5) can also be used.

Equation (F-5):

CH ₂ =CX ₁ -COO-CHY-CH ₂ -OCO-CX ₂ =CH ₂

(In the formula, X ₁ and X ₂ each independently represent a hydrogen atom or a methyl group, and Y is a fluoroalkyl group having 2 to 20 carbon atoms having 3 or more fluorine atoms, or a fluorine having 4 to 20 carbon atoms having 4 or more fluorine atoms. It represents a cycloalkyl group.)

In this embodiment, the compound in which the polymerizable unsaturated group is a (meth)acryloyloxy group may have a plurality of (meth)acryloyloxy groups. When the fluorinated antifouling agent has a plurality of (meth)acryloyloxy groups, when cured, it exhibits a three-dimensional network structure, the glass transition temperature is high, the transferability of the antifouling agent is low, and the stain is repeatedly wiped off. It can improve the durability. Furthermore, a cured film excellent in heat resistance and weather resistance can be obtained.

As a specific example of the compound represented by formula (F-5), for example, di(meth)acrylic acid-2,2,2-trifluoroethylethylene glycol, di(meth)acrylic acid-2,2,3,3 ,3-pentafluoropropylethylene glycol, di(meth)acrylic acid-2,2,3,3,4,4,4-heptafluorobutylethylene glycol, di(meth)acrylic acid-2,2 ,3,3,4,4,5,5,5-nonafluoropentylethylene glycol, di(meth)acrylic acid-2,2,3,3,4,4,5,5,6,6, 6-undecafluorohexylethylene glycol, di(meth)acrylic acid-2,2,3,3,4,4,5,5,6,6,7,7,7-tridecafluoroheptylethylene Glycol, di(meth)acrylic acid-2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctylethylene glycol, Di(meth)acrylic acid-3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctylethylene glycol, di(meth)acrylic acid-2, 2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-heptadecafluorononylethylene glycol, di(meth)acrylic acid-2, 2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-nonadecafluorodecylethylene glycol, di(meth) Acrylic acid-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecylethylene glycol, di(meth) Acrylic acid-2-trifluoromethyl-3,3,3-trifluoropropylethylene glycol, di(meth)acrylic acid-3-trifluoromethyl-4,4,4-trifluorobutylethylene glycol Cole, di(meth)acrylate-1-methyl-2,2,3,3,3-pentafluoropropylethylene glycol, di(meth)acrylate-1-methyl-2,2,3,3,4 ,4,4-heptafluorobutylethylene glycol and the like are preferably mentioned, and when used, they can be used alone or as a mixture. Such di(meth)acrylic acid ester can be produced by a known method exemplified in Japanese Laid-Open Patent Publication No. Hei 6-306326. In this embodiment, diacrylic acid-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-heptadecafluorononylethylene glycol Lycol is preferably used.

In this embodiment, as a compound in which the polymerizable unsaturated group is a (meth)acryloyloxy group, it may be a compound having a plurality of (per)fluoroalkyl groups or (per)fluoropolyether groups in one molecule.

The fluorinated antifouling agent in this embodiment may be any of a monomer, an oligomer, or a polymer. It is preferable that the fluorinated antifouling agent further has a substituent which contributes to bond formation or compatibility in the hard coat layer film. These substituents may be the same or different, and it is preferable that there are two or more. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, allyl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group, amino group, and the like.

The fluorinated antifouling agent may be a polymer or an oligomer with a compound not containing a fluorine atom.

Moreover, the fluorine-containing compound may contain a silicon atom in a molecule, may contain a siloxane structure, and may have a structure other than a siloxane structure. However, when the fluorinated compound having a polymerizable unsaturated group contains a siloxane structure, the weight average molecular weight is less than 15000.

When the fluorinated compound contains a siloxane structure, the fluorinated compound is preferably represented by the following formula (F-6).

Equation (F-6):

R _a R ^f _b R ^A _c SiO _(4-abc)/2

(Wherein, R is a hydrogen atom, a methyl group, an ethyl group, a propyl group or a phenyl group, R ^f is an organic group containing a fluorine atom, R ^A is an organic group containing a polymerizable unsaturated group, 0<a, 0< b, 0<c, a+b+c<4.)

a is preferably 1 to 1.75, more preferably 1 to 1.5, and when it is 1 or more, synthesis of the compound becomes industrially easy, and when it is 1.75 or less, it becomes easy to achieve both curability and antifouling properties.

Examples ^{of the polymerizable unsaturated group for R A} _{include the same polymerizable unsaturated group as for R A} in the formula (F), and preferably a (meth)acryloyl group, a (meth)acryloyloxy group, and these Any hydrogen atom in the group is a group substituted with a fluorine atom.

When the fluorinated compound contains a siloxane structure, a preferable example of the siloxane structure includes a structure having a substituent at the terminal and/or side chain of the compound chain containing a plurality of dimethylsilyloxy units as repeating units. In the compound chain containing dimethylsilyloxy as a repeating unit, structural units other than dimethylsilyloxy may be included. The substituents may be the same or different, and it is preferable that there are a plurality of substituents. Examples of preferred substituents include (meth)acryloyl group, (meth)acryloyloxy group, vinyl group, allyl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, fluoroalkyl group, polyoxyalkylene group, carboxyl group, amino group And the like, and particularly, a (meth)acryloyloxy group is preferable from the viewpoint of suppressing bleeding out of the antifouling agent. Further, as the number of substituents, 1500 to 20000 g·mol ⁻¹ as a functional group equivalent is preferable from the viewpoint of improving the ubiquitousness of the antifouling agent and suppressing bleed-out.

R ^f is an organic group containing a fluorine atom, and a group represented by C _x F _2x+1 (CH ₂ ) _p- (wherein x is an integer of 1 to 8, p is an integer of 2 to 10) or perfluoro It is preferably a low polyether substituted alkyl group. b is preferably 0.2 to 0.4, more preferably 0.2 to 0.25, and if it is 0.2 or more, antifouling property is improved, and if it is 0.4 or less, curing property is improved. It is preferable that R ^f is a C8 perfluoroalkyl group.

R ^A is an organic group containing a (meth)acrylic group, and it is more preferable that the bond to the Si atom is a Si-OC bond from the ease of industrial synthesis. c is preferably 0.4 to 0.8, more preferably 0.6 to 0.8, and when it is 0.4 or more, curability is improved, and when it is 0.8 or less, antifouling property is improved.

In addition, a+b+c is preferably 2 to 2.7, more preferably 2 to 2.5, and if it is less than 2, it becomes difficult to cause localization on the surface, and if it is greater than 2.7, it is impossible to achieve both hardenability and antifouling properties. Tend to be.

When the fluorinated compound contains a siloxane structure, the fluorinated compound contains 3 or more F atoms and 3 or more Si atoms, preferably 3 to 17 F atoms and 3 to 3 Si atoms per molecule. It is preferable to contain eight. When there are 3 or more F atoms, the antifouling property becomes sufficient, and when there are 3 or more Si atoms, localization on the surface is promoted, and the antifouling property becomes sufficient.

When the fluorinated compound contains a siloxane structure, the fluorinated compound can be produced using a known method or the like exemplified in Japanese Patent Laid-Open No. 2007-145884.

When the fluorinated compound contains a siloxane structure, the siloxane structure may be linear, branched, or cyclic, but among these, a compound having a branched or cyclic structure particularly has an unsaturated double bond to be described later. It is preferable because it has good compatibility with a compound or the like, there is no cissing, and localization on the surface tends to occur.

Here, as a compound in which the siloxane structure is branched, a compound represented by the following formula (F-7) is preferable.

Equation (F-7):

R ^f SiR _k 〔OSiR _m (OR ^A ) _3-m 〕 _3-k

(In the formula, R, R ^f , and R ^A are the same as above, m = 0, 1 or 2, particularly m = 2, and k = 0 or 1.)

Moreover, as a compound in which the siloxane structure has a cyclic structure, a compound represented by the following formula (F-8) is preferable.

Equation (F-8):

(R ^f RSiO)(R ^A RSiO) _n (In the formula, R, R ^f , and R ^A are the same as above, and n=2, especially 3≦n≦5.)

The following compounds etc. are mentioned as a specific example of such a fluorinated polysiloxane compound.

[Formula 11]

The weight average molecular weight (Mw) of the fluorinated antifouling agent can be measured using molecular exclusion chromatography, for example, gel permeation chromatography (GPC). The Mw of the fluorinated antifouling agent used in this embodiment is preferably 400 or more and less than 5000, more preferably 1000 or more and less than 5000, and still more preferably 1000 or more and less than 3500. When Mw is 400 or more, since the surface transferability of the antifouling agent becomes high, it is preferable. In addition, when Mw is less than 5000, the surface migration property of the fluorinated antifouling agent cannot be hindered between coating and curing processes, and since it is easy to uniformly orientate the surface of the hard coat layer, antifouling properties and film hardness are improved. desirable.

However, when the fluorinated compound contains a siloxane structure, Mw is less than 15000, preferably 1000 or more and less than 5000, and more preferably 1000 or more and less than 3500.

The addition amount of the fluorinated antifouling agent is preferably 1 to 20% by mass, more preferably 1 to 15% by mass, more preferably 1 to 10% by mass with respect to the total solid content in the hard coat layer or the composition for forming a hard coat layer. desirable. When the addition amount of the fluorinated antifouling agent is 1% by mass or more with respect to the total solid content in the hard coat layer or the composition for forming a hard coat layer, the proportion of the antifouling agent having water and oil repellency becomes appropriate, and sufficient antifouling properties are obtained. In addition, if the addition amount of the fluorinated antifouling agent is 20% by mass or less with respect to the total solid content in the hard coat layer or the composition for forming a hard coat layer, the antifouling agent that cannot be mixed with the resin component does not precipitate on the surface, and the film is whitened or It is preferable because it does not generate white powder.

The fluorine atom content of the fluorinated antifouling agent is not particularly limited, but it is preferably 20% by mass or more, particularly preferably 30 to 70% by mass, and most preferably 40 to 70% by mass.

Examples of preferred fluorinated antifouling agents include Daikin Chemical Co., Ltd., R-2020, M-2020, R-3833, M-3833, Optool DAC (above brand name), DIC, Megapac F-171, F -172, F-179A, Defender MCF-300, MCF-323 (the above brand name), etc. are mentioned, but are not limited to these.

[Polysiloxane compound having a weight average molecular weight of 15000 or more having a polymerizable unsaturated group]

Next, a polysiloxane compound having a weight average molecular weight of 15000 or more having a polymerizable unsaturated group that can be used as the component g) will be described. In addition, hereinafter, a polysiloxane compound having a molecular weight of 15000 or more is referred to as a "polysiloxane antifouling agent".

One aspect of a preferred example of the polysiloxane antifouling agent is a compound represented by the above-described formula (F-6).

Preferred examples of the polysiloxane antifouling agent include a compound having a substituent at the terminal and/or side chain of a compound chain containing a plurality of dimethylsilyloxy units as repeating units. In the compound chain containing dimethylsilyloxy as a repeating unit, structural units other than dimethylsilyloxy may be included. The substituents may be the same or different, and it is preferable that there are a plurality of substituents. Examples of preferred substituents include (meth)acryloyl group, (meth)acryloyloxy group, vinyl group, allyl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, fluoroalkyl group, polyoxyalkylene group, carboxyl group, amino group And the like, and particularly, a (meth)acryloyloxy group is preferable from the viewpoint of suppressing bleeding out of the antifouling agent. Further, as the number of substituents, 1500 to 20000 g·mol ⁻¹ as a functional group equivalent is preferable from the viewpoint of improving the ubiquitousness of the antifouling agent and suppressing bleed-out.

The polysiloxane antifouling agent is preferably a compound containing 3 or more F atoms and 3 or more Si atoms, preferably 3 to 17 F atoms and 3 to 8 Si atoms per molecule. When there are 3 or more F atoms, the antifouling property becomes sufficient, and when there are 3 or more Si atoms, localization on the surface is promoted, and the antifouling property becomes sufficient.

The polysiloxane antifouling agent can be produced using a known method or the like exemplified in Japanese Patent Laid-Open No. 2007-145884.

As an additive having a polysiloxane structure, a reactive group-containing polysiloxane (for example, "KF-100T", "X-22-169AS", "KF-102", "X-22-3701IE", "X-22- 164C", "X-22-5002", "X-22-173B", "X-22-174D", "X-22-167B", "X-22-161AS" (brand name), above, Shin-Etsu Kagaku High School Co., Ltd. product; "AK-5", "AK-30", "AK-32" (trade name), Sangdo Kosei Co., Ltd. product; "Silaplane FM0725", "Silaplane FM0721" (brand name), and above, manufactured by JNC Co., Ltd.; It is also preferable to add "DMS-U22", "RMS-033", "UMS-182" (trade name), the above Gelest agent, etc.] In addition, as described in Table 2 or Table 3 of Japanese Unexamined Patent Application Publication No. 2003-112383 Silicone compounds can also be preferably used.

The siloxane structure contained in the polysiloxane antifouling agent may be linear, branched, or cyclic, but among these, compounds having a branched or cyclic structure are particularly compatible with compounds having an unsaturated double bond described below. This is preferable because it is good, there is no sheathing, and localization to the surface is liable to occur.

The weight average molecular weight of the polysiloxane antifouling agent is 15000 or more, preferably 15000 or more and 50000 or less, and more preferably 18000 or more and 30000 or less. If the weight average molecular weight of the polysiloxane antifouling agent is less than 15000, the surface unevenness of the polysiloxane is reduced, which is not preferable from the viewpoint of causing deterioration in antifouling properties and a decrease in hardness. However, when the fluorinated compound having a polymerizable unsaturated group has a polysiloxane structure, the above problem does not occur.

The weight average molecular weight of the polysiloxane antifouling agent can be measured using molecular exclusion chromatography, for example, gel permeation chromatography (GPC).

The amount of the polysiloxane antifouling agent added is preferably 1% by mass or more and less than 25% by mass, more preferably 1% by mass or more and less than 20% by mass, based on the total solid content in the hard coat layer or the composition for forming a hard coat layer. % Or more and less than 15 mass% are more preferable, and 1 mass% or more and less than 10 mass% are most preferable. When the addition amount of the polysiloxane antifouling agent is 1% by mass or more with respect to the total solid content in the hard coat layer or the composition for forming a hard coat layer, the proportion of the antifouling agent having water and oil repellency becomes appropriate, and sufficient antifouling properties are obtained. In addition, when the addition amount of the polysiloxane antifouling agent is less than 25% by mass relative to the total solid content in the hard coat layer or the composition for forming a hard coat layer, the antifouling agent that cannot be mixed with the resin component does not precipitate on the surface, the film is whitened, or the surface It is preferable because it does not generate 100 minutes.

The distribution state of the antifouling agent in the hard coat layer in the film thickness direction is when X is the amount of fluorine or silicon in the vicinity of the surface of the hard coat layer, and Y is the amount of fluorine or silicon in the entire hard coat layer. , It is preferable to satisfy 51%<X/Y<100%. When X/Y is larger than 51%, the antifouling agent is not distributed to the inside of the film of the hard coat layer, and it is preferable from the viewpoint of antifouling properties and film hardness. In addition, the vicinity of the surface refers to a region with a depth of less than 1 μm from the surface of the hard coat layer, and of the F-fragment or Si ₂ C ₅ H ₁₅ O ⁺ fragment measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS). It can be measured in proportions.

g) The antifouling agent is preferably an antifouling agent that dissolves in a liquid or a solvent at 20°C. As the solvent, it can be appropriately selected depending on the polarity of the compound, but an organic solvent that is miscible with dimethyl carbonate is preferable, and an aliphatic or aromatic alcohol, ketone, ester, and ether solvent can be mentioned. It is particularly preferable if it is dissolved in dimethyl carbonate.

g) As for the surface tension of the antifouling agent, from the viewpoint of antifouling properties, the surface tension is preferably 25.0 mN/m or less, more preferably 23.0 mN/m or less, and still more preferably 16.0 mN/m or less.

The surface tension of the antifouling agent is the surface tension in a single film, and can be measured as follows.

(Measurement method of surface tension of antifouling agent)

An antifouling agent was spin-coated on a quartz substrate, and when it contained a solvent, it dried and produced the film. Subsequently, using a contact angle meter ["CA-X" type contact angle meter, manufactured by Kyowa Kaimen Chemical Co., Ltd.] in a dry state (20°C/65%RH), using pure water as a liquid, with a diameter of 1.0 mm. A droplet of was made at the tip of the needle, and it was brought into contact with the surface of the spin coat film to form a droplet on the film. The angle formed by the tangent to the liquid surface and the film surface at the point where the film and the liquid are in contact, was measured by taking the angle of the side containing the liquid as the contact angle. Moreover, the contact angle was measured using methylene iodide instead of water, and the surface free energy was calculated|required from the following formula.

What is surface free energy (γs ^v : unit, mN/m)? DK Owens: J. Appl. Polym. Referring to Sci., 13, 1741 (1969), the following simultaneous equations a, b from the contact angles θ _H2O and θ _{CH2I2 of pure H 2} O and methylene iodide CH ₂ I _{2 obtained experimentally on an anti-reflective film} It was defined ^{as the value γs v} (=γs ^d +γs ^h ) represented by the sum of ^{γs d} and γs ^h obtained from.

a. 1+cosθ _H2O =2√γs ^d (√γ _H2O ^d /γ _H2O ^v )+2√γs ^h (√γ _H2O ^h /γ _H2O ^v )

b. 1+cosθ _CH2I2 =2√γs ^d (√γ _CH2I2 ^d /γ _CH2I2 ^v )+2√γs ^h (√γ _CH2I2 ^h /γ _CH2I2 ^v )γ _H2O ^d =21.8, γ _H2O ^h =51.0, γ _H2O ^v = 72.8, γ _CH2I2 ^d =49.5, γ _CH2I2 ^h =1.3, γ _CH2I2 ^v =50.8

As g) antifouling agent described above, a compound synthesized by a known method may be used, or a commercial item may be used. As a commercial item, RS-90, RS-78, etc. manufactured by DIC can be preferably used.

(menstruum)

The composition for forming a hard coat layer in this embodiment may contain a solvent. As a solvent, various selected from the viewpoints of dissolving or dispersing each component, easily forming a uniform surface shape in the coating process and drying process, ensuring liquid storage, and having an appropriate saturated vapor pressure, etc. Solvent can be used.

The solvent can be used by mixing two or more types of solvents. In particular, from the viewpoint of drying load, it is preferable to contain a solvent having a boiling point of 100°C or less at room temperature at normal pressure as a main component, and containing a small amount of a solvent having a boiling point of more than 100°C for adjustment of the drying rate.

In the composition for forming a hard coat layer in this embodiment, in order to prevent sedimentation of particles, it is preferable to contain a solvent having a boiling point of 80° C. or less in the total solvent of the coating composition in 30 to 80 mass%, and 50 to 70 It is more preferable to contain the mass. By setting the solvent ratio having a boiling point of 80° C. or less as the above ratio, absorption of the resin component to the polyester film is appropriately suppressed, and further, by increasing the viscosity increase rate due to drying, particle sedimentation can be suppressed.

Examples of the solvent having a boiling point of 100°C or less include hydrocarbons such as hexane (boiling point 68.7°C), heptane (98.4°C), cyclohexane (80.7°C), and benzene (80.1°C), and dichloromethane ( 39.8°C), chloroform (61.2°C), carbon tetrachloride (76.8°C), 1,2-dichloroethane (83.5°C), halogenated hydrocarbons such as trichloroethylene (87.2°C), diethyl ether (34.6°C), diisopropyl ether (68.5°C), dipropyl ether (90.5°C), ethers such as tetrahydrofuran (66°C), ethyl formate (54.2°C), methyl acetate (57.8°C), Esters such as ethyl acetate (77.1°C) and isopropyl acetate (89°C), ketones such as acetone (56.1°C), 2-butanone (methylethylketone, same as MEK, 79.6°C), methanol (64.5°C) , Alcohols such as ethanol (78.3°C), 2-propanol (82.4°C) and 1-propanol (97.2°C), cyano compounds such as acetonitrile (81.6°C) and propionitryl (97.4°C), 2 Carbon sulfide (46.2℃). Among these, ketones and esters are preferred, and ketones are particularly preferred. Among ketones, 2-butanone is particularly preferred.

As a solvent with a boiling point higher than 100°C, for example, octane (125.7°C), toluene (110.6°C), xylene (138°C), tetrachloroethylene (121.2°C), chlorobenzene (131.7°C), dioxane ( 101.3°C), dibutyl ether (142.4°C), isobutyl acetate (118°C), cyclohexanone (155.7°C), 2-methyl-4-pentanone (same as MIBK, 115.9°C), 1-butanol (117.7°C), N,N-dimethylformamide (153°C), N,N-dimethylacetamide (166°C), and dimethyl sulfoxide (189°C). Preferably, they are cyclohexanone and 2-methyl-4-pentanone.

(Surfactants)

It is also suitable to use various surfactants and/or wind unevenness inhibitors (hereinafter, collectively referred to as surfactants) for the hard coat layer or the composition for forming a hard coat layer in the present embodiment. In general, the surfactant and/or the wind non-uniformity preventing agent can suppress film thickness non-uniformity and the like caused by drying unevenness caused by local distribution of dry air.

As the surfactant, specifically, it is preferable to contain a fluorine-based surfactant, a silicone-based surfactant, or both. Moreover, it is preferable that a surfactant is an oligomer or a polymer rather than a low molecular compound.

Preferred examples of the fluorine-based surfactant include a fluoroaliphatic group-containing copolymer (hereinafter, sometimes abbreviated as "fluorine-based polymer"), and the fluorine-based polymer is a repeating unit corresponding to the monomer of the following (i). Or a repeating unit corresponding to the monomer of (i) and a repeating unit corresponding to the monomer of (ii) below, and copolymerization of an acrylic resin, a methacrylic resin, and a vinyl-based monomer copolymerizable thereto Coalescence is useful.

(i) a fluoro aliphatic group-containing monomer represented by the following formula (i)

Equation (i)

[Formula 12]

In formula (i), R ¹¹ represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom or -N(R ¹² )-, m is an integer of 1 or more and 6 or less, and n is an integer of 2 to 4 Represents. R ¹² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, specifically a methyl group, an ethyl group, a propyl group, or a butyl group, and preferably a hydrogen atom or a methyl group. X is preferably an oxygen atom.

(ii) a monomer represented by the following formula (ii) capable of copolymerizing with the above (i)

Equation (ii)

[Formula 13]

In formula (ii), R ¹³ represents a hydrogen atom or a methyl group, Y represents an oxygen atom, a sulfur atom or -N(R ¹⁵ )-, and R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, specifically Represents a methyl group, an ethyl group, a propyl group, or a butyl group, and is preferably a hydrogen atom or a methyl group. Y is preferably an oxygen atom, -N(H)-, and -N(CH ₃ )-.

R ¹⁴ represents a C 4 or more and 20 or less linear, branched or cyclic alkyl group which may have a substituent. Examples of the substituent of the alkyl group of R ¹⁴ include a hydroxyl group, an alkylcarbonyl group, an arylcarbonyl group, a carboxyl group, an alkyl ether group, an aryl ether group, a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom, a nitro group, and a cyano group. Group, amino group, and the like, but are not limited thereto. As a C4 or more and 20 or less linear, branched or cyclic alkyl group, which may be linear or branched, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group , Tetradecyl group, pentadecyl group, octadecyl group, eicosanyl group, etc., and monocyclic cycloalkyl groups such as cyclohexyl group and cycloheptyl group, and bicycloheptyl group, bicyclodecyl group, tricycloundecyl group, tetracyclodode Polycyclic cycloalkyl groups, such as an actual group, an adamantyl group, a norbornyl group, and a tetracyclodecyl group, are used suitably.

The amount of the fluoroaliphatic group-containing monomer represented by the formula (i) used in the fluorine-based polymer is 10 mol% or more, preferably 15 to 70 mol%, more preferably, based on each monomer of the fluorine-based polymer. It is in the range of 20 to 60 mol%.

As for the preferable mass average molecular weight of a fluorine-type polymer, 3000-100,000 are preferable, and 5,000-80,000 are more preferable. Further, the preferred addition amount of the fluorine-based polymer is in the range of 0.001 to 5 parts by mass, more preferably in the range of 0.005 to 3 parts by mass, and still more preferably in the range of 0.01 to 1 part by mass with respect to 100 parts by mass of the coating liquid. If the amount of the fluorine-based polymer is 0.001 parts by mass or more, the effect of adding the fluorine-based polymer is sufficiently obtained, and if it is 5 parts by mass or less, the coating film cannot be sufficiently dried or adversely affects the performance of the coating film. Does not.

Examples of preferred silicone compounds include X-22-174DX, X-22-2426, X22-164C, and X-22-176D (the above brand names) manufactured by Shin-Etsu Chemical Co., Ltd.; FM-7725, FM-5521, FM-6621 (above brand name) manufactured by JNC Co., Ltd.; Gelest's DMS-U22, RMS-033 (the above brand name); SH200, DC11PA, ST80PA, L7604, FZ-2105, L-7604, Y-7006, SS-2801 (above brand names) manufactured by Toray Dow Corning Co., Ltd.; Momentive Performance Materials Japan TSF400 (brand name) and the like are mentioned, but are not limited thereto.

When the total solid content of the composition for forming a hard coat layer in the present embodiment is 100% by mass, the silicone-based surfactant is preferably contained in an amount of 0.01 to 0.5% by mass, and more preferably 0.01 to 0.3% by mass.

(Matte particles)

The hard coat layer or the composition for forming a hard coat layer may contain mat particles having an average particle diameter of 1.0 to 15.0 μm, preferably 1.5 to 10.0 μm for the purpose of imparting internal scattering property or imparting surface irregularities. Further, in order to adjust the viscosity of the coating liquid, a polymer compound or an inorganic layer-like compound may be included. You may use e) as a mat particle.

The hard coat film according to one aspect of the present disclosure may contain other layers (arbitrary layers) in addition to the polyester film and the hard coat layer according to the present embodiment described above. Examples of such an arbitrary layer include an easily adhesive layer, an antireflection layer (a laminated film of one or more high refractive index layers and one or more low refractive index layers), an antiglare layer, an antistatic layer, etc., but is not limited thereto. Does not. For these arbitrary layers, paragraphs 0069 to 0091 of Japanese Patent Publication No. 5048304 can be referred to, for example. In addition, a decorative layer may be provided in the hard coat film according to the present embodiment.

Although an example of a preferable layer configuration of the hard coat film according to the present embodiment is shown below, it is not particularly limited to these layer configurations.

·Polyester film/hard coat layer

Polyester film/hard coat layer/low refractive index layer

Polyester film/hard coat layer/anti-glare layer (antistatic layer)/low refractive index layer,

Polyester film/hard coat layer/glare layer/antistatic layer/low refractive index layer,

Polyester film/hard coat layer/antistatic layer/anti-glare layer/low refractive index layer,

Polyester film/hard coat layer (antistatic layer)/anti-glare layer/low refractive index layer,

Polyester film/hard coat layer/high refractive index layer/antistatic layer/low refractive index layer,

Polyester film/hard coat layer/high refractive index layer (antistatic layer)/low refractive index layer,

Polyester film/hard coat layer/antistatic layer/high refractive index layer/low refractive index layer,

Polyester film/hard coat layer/medium refractive index layer/high refractive index layer (antistatic layer)/low refractive index layer,

Polyester film/hard coat layer/medium refractive index layer (antistatic layer)/high refractive index layer/low refractive index layer,

Polyester film/hard coat layer (antistatic layer)/medium refractive index layer/high refractive index layer/low refractive index layer,

Polyester film/antistatic layer/hard coat layer/medium refractive index layer/high refractive index layer/low refractive index layer,

Antistatic layer/polyester film/hard coat layer/medium refractive index layer/high refractive index layer/low refractive index layer,

Here, the antistatic layer and the antiglare layer may have a hard coat property.

(Low refractive index layer)

In the hard coat film according to the present embodiment, a low refractive index layer may be formed on the hard coat layer for the purpose of imparting a reflectance reducing effect. The low refractive index layer has a lower refractive index than the hard coat layer, and the thickness is preferably 50 to 200 nm, more preferably 70 to 150 nm, and most preferably 80 to 120 nm.

The refractive index of the low refractive index layer is lower than the refractive index of the layer immediately below, preferably 1.20 to 1.55, more preferably 1.25 to 1.46, and particularly preferably 1.30 to 1.40.

The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm.

The low refractive index layer is preferably obtained by curing a curable composition for forming a low refractive index layer.

As an aspect of the curable composition of a preferable low refractive index layer,

(1) a composition containing a fluorinated compound having a crosslinkable or polymerizable functional group,

(2) a composition containing as a main component a hydrolyzed condensate of a fluorinated organosilane material,

(3) A composition containing a monomer having two or more ethylenically unsaturated groups and inorganic particles (particularly, inorganic particles having a hollow structure are preferable), and the like can be mentioned.

Regarding each composition of the above (1) and (2), it is preferable to contain inorganic particles, and when inorganic particles further having a hollow structure having a low refractive index are used, the refractive index is reduced or the amount of inorganic particles added and the refractive index are adjusted. It is particularly preferred from the viewpoint.

(1) A composition containing a fluorinated compound having a crosslinkable or polymerizable functional group

Examples of the fluorinated compound having a crosslinkable or polymerizable functional group include a fluorinated polymer which is a copolymer of a fluorinated monomer and a monomer having a crosslinkable or polymerizable functional group. Specific examples of these fluorinated polymers are described in Japanese Unexamined Patent Application Publication No. 2003-222702, Japanese Unexamined Patent Application Publication No. 2003-183322, and the like.

In addition, the fluorinated polymer described above may be appropriately used in combination with a curing agent having a polymerizable unsaturated group as described in Japanese Laid-Open Patent Publication No. 2000-17028. Moreover, as described in Japanese Patent Application Laid-Open No. 2002-145952, it is also preferable to use it in combination with a compound having a fluorinated polyfunctional polymerizable unsaturated group. Examples of the compound having a polyfunctional polymerizable unsaturated group include a monomer having two or more ethylenically unsaturated groups described as the curable resin compound of the low refractive index layer. Further, the hydrolyzed condensate of organosilane described in Japanese Patent Application Laid-Open No. 2004-170901 is also preferred, and particularly, the hydrolyzed condensate of organosilane containing a (meth)acryloyl group is preferred. These compounds are particularly preferable because of their combined effect on improving scratch resistance when a compound having a polymerizable unsaturated group is used in the polymer body.

When the polymer itself does not have sufficient curability, it is possible to impart necessary curability by blending a crosslinkable compound. For example, when the polymer body contains a hydroxyl group, it is preferable to use various amino compounds as a curing agent. The amino compound used as the crosslinkable compound is, for example, a compound containing two or more of either or both of a hydroxyalkylamino group and an alkoxyalkylamino group in total, and specifically, for example, a melamine-based compound or a urea And benzoguanamine-based compounds, glycoluril-based compounds, and the like. For curing these compounds, it is preferable to use an organic acid or a salt thereof.

(2) A composition containing a hydrolyzed condensate of a fluorinated organosilane material as a main component

A composition containing as a main component a hydrolyzed condensate of a fluorinated organosilane compound is also preferable because of its low refractive index and high hardness of the surface of the coating film. A condensation product of tetraalkoxysilane and a compound containing hydrolyzable silanol at one or both ends of the fluorinated alkyl group is preferred. Specific compositions are described in Japanese Patent Application Laid-Open No. 2002-265866 and Japanese Patent Application No. 317152.

(3) A composition containing a monomer having two or more ethylenically unsaturated groups and inorganic particles having a hollow structure

Further, as another preferred embodiment, a low refractive index layer made of low refractive index particles and a resin is exemplified. Although organic or inorganic may be sufficient as a low refractive index particle, particle|grains which have voids inside are preferable. As a specific example of the hollow particle, a silica-based particle described in Japanese Unexamined Patent Application Publication No. 2002-79616 can be mentioned. The particle refractive index is preferably 1.15 to 1.40, more preferably 1.20 to 1.30. Examples of the resin include monomers having two or more ethylenically unsaturated groups described on the page of the anti-glare layer.

It is preferable to add a photo radical polymerization initiator or a thermal radical polymerization initiator to the composition for forming a low refractive index layer used in the present embodiment. In the case of containing a radically polymerizable compound, 1 to 10 parts by mass, preferably 1 to 5 parts by mass of a polymerization initiator can be used based on the compound.

In the low refractive index layer used in this embodiment, inorganic particles can be used in combination. In order to impart scratch resistance, particles having a particle diameter of 15% to 150%, preferably 30% to 100%, more preferably 45% to 60% of the thickness of the low refractive index layer may be used.

To the low refractive index layer used in the present embodiment, for the purpose of imparting properties such as antifouling properties, water resistance, chemical resistance, and sliding properties, a known polysiloxane-based or fluorine-based antifouling agent, a sliding agent, and the like can be appropriately added.

As an additive having a polysiloxane structure, a reactive group-containing polysiloxane (e.g., KF-100T, X-22-169AS, KF-102, X-22-37-01IE, X-22-164B, X-22-5002 , X-22-173B, X-22-174D, X-22-167B, X-22-161AS (brand name), above, manufactured by Shin-Etsu Chemical Co., Ltd.; AK-5, AK-30, AK-32 (trade name), Sangdoa Kosei Co., Ltd. product; It is also preferable to add "Sila plain FM0725", "Sila plain FM0721" (brand name), the above JNC Co., Ltd. product etc.}. Further, the silicone compounds described in Tables 2 and 3 of JP 2003-112383 A can also be preferably used.

As the fluorine-based compound, a compound having a fluoroalkyl group is preferable. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10, and a straight chain (eg -CF ₂ CF ₃ , -CH ₂ (CF ₂ ) ₄ H, -CH ₂ (CF ₂ ) ₈ CF ₃ , -CH ₂ CH ₂ (CF ₂ ) ₄ H, etc.), and branched structures (e.g., CH(CF ₃ ) ₂ , CH ₂ CF(CF ₃ ) ₂ , CH(CH ₃ )CF ₂₎ CF ₃ , CH (CH ₃ ) (CF ₂ ) ₅ CF ₂ H, etc.) may be used, and an alicyclic structure (preferably a 5- or 6-membered ring, such as a perfluorocyclohexyl group, a perfluorocyclopentyl group) Or an alkyl group substituted with these), and may have an ether bond (e.g., CH ₂ OCH ₂ CF ₂ CF ₃ , CH ₂ CH ₂ OCH ₂ C ₄ F ₈ H, CH ₂ CH ₂ OCH ₂ CH ₂ C ₈ F ₁₇ , CH ₂ CH ₂ OCF ₂ CF ₂ OCF ₂ CF ₂ H, etc.). A plurality of the fluoroalkyl groups may be contained in the same molecule.

It is preferable that the fluorine-based compound further has a substituent that contributes to the formation of bonds or compatibility with the low refractive index layer coating. The substituents may be the same or different, and it is preferable that there are a plurality of substituents. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group, amino group, and the like. The fluorine-based compound may be a polymer or an oligomer with a compound not containing a fluorine atom, and there is no particular limitation on the molecular weight. The fluorine atom content of the fluorine-based compound is not particularly limited, but it is preferably 20% by mass or more, particularly preferably 30 to 70% by mass, and most preferably 40 to 70% by mass. Examples of preferred fluorine-based compounds include Daikin Chemical Industries, Ltd., R-2020, M-2020, R-3833, M-3833, Optool DAC (the above brand name), DIC, Megapac F-171, F-172. , F-179A, Defender MCF-300, MCF-323 (above brand name), and the like, but are not limited thereto.

These polysiloxane fluorine-based compounds or compounds having a polysiloxane structure are preferably added in the range of 0.1 to 10% by mass of the total solid content of the low refractive index layer, and particularly preferably 1 to 5% by mass.

[How to apply the hard coat layer]

The hard coat layer according to the hard coat film of the present disclosure can be formed by the following method.

First, a composition for forming a hard coat layer is prepared. Next, the composition is applied onto a polyester film (base film) by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, a die coating method, etc., and heating · Dry. A microgravure coating method, a wire bar coating method, and a die coating method (see US Patent Publication No. 2681294 and JP 2006-122889 A) are more preferable, and a die coating method is particularly preferable.

After the hard coat layer is applied on the base film, it is conveyed as a web to the heated zone in order to dry the solvent. The temperature of the drying zone at that time is preferably 25°C to 140°C, the first half of the drying zone is relatively low temperature, and the second half is preferably relatively high temperature. However, it is preferable that it is below the temperature at which the volatilization of components other than the solvent contained in the coating composition of each layer starts. For example, some commercially available photo radical generators that are used in combination with ultraviolet curing resins evaporate about 10% of them within a few minutes in warm air at 120°C, and monofunctional and bifunctional acrylate monomers are 100°C. Some of the warm air in the country undergo volatilization. In such a case, it is preferable that it is below the temperature at which the volatilization of components other than the solvent contained in the coating composition of the hard coat layer starts as described above.

In addition, the dry air after applying the coating composition of the hard coat layer on the base film is that when the solid content concentration of the coating composition is between 1 and 50%, the wind speed on the surface of the coating film is in the range of 0.1 to 2 m/sec, This is preferable because it prevents uneven drying.

In addition, after applying the coating composition of the hard coat layer on the base film, if the temperature difference between the transfer roll and the base film in contact with the surface opposite to the coated surface of the base film in the drying zone is within 0°C to 20°C, Drying unevenness due to heat transfer unevenness on the conveying roll can be prevented, which is preferable.

After the drying zone of the solvent, a zone for curing the hard coat layer by irradiation with ionizing radiation is passed through the web to cure the coating film. For example, if the coating is UV-curing, it is preferred that the irradiation dose of ultraviolet ray of ^{10mJ / cm 2 ~ 1000mJ / cm} 2 to cure the coating film by the ultraviolet lamp. In that case, the distribution of the irradiation amount in the width direction of the web is preferably 50 to 100% of the distribution including both ends of the maximum irradiation amount in the center, and more preferably 80 to 100% of the distribution. In addition, when it is necessary to reduce the oxygen concentration by purging nitrogen gas or the like in order to accelerate the surface hardening, the oxygen concentration is preferably 0.01% to 5%, and the distribution in the width direction is preferably 2% or less in terms of oxygen concentration. In the case of ultraviolet irradiation, ultraviolet rays emitted from light sources such as ultra high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, xenon arcs, metal halide lamps, etc. can be used. Further, in order to accelerate the curing reaction, the temperature may be increased during curing, and the temperature is preferably 25 to 100°C, more preferably 30 to 80°C, and most preferably 40 to 70°C.

In addition, other functional layers may be provided as needed. In the case of laminating other functional layers in addition to the hard coat layer, a plurality of layers may be applied at the same time or may be applied sequentially. The manufacturing method of these layers can be performed according to the manufacturing method of a hard coat layer.

The use of the polyester film according to the present embodiment is not particularly limited, and it can be suitably used for applications in which the occurrence of recesses is required to be suppressed when a load is applied.

In addition to the base film of the hard coat film, the polyester film according to the present embodiment can be suitably used as a base film for various functional films such as a sensor film for touch panels, an anti-scattering film, and an anti-reflection film, for example.

[Shatterproof film]

The scattering prevention film according to the present embodiment is a scattering prevention film in which an adhesive layer is laminated on at least one side of the polyester film according to the present embodiment. The polyester film according to this embodiment can be used for a scattering prevention film. As for the scattering prevention film, it is preferable that a hard coat layer and an adhesive layer are laminated|stacked on a polyester film.

The adhesive layer may be formed by either a wet coating method or a dry coating method. For forming the adhesive layer, an acrylic adhesive composition such as a solvent-based acrylic polymer or a solvent-based acrylic syrup, a solvent-free acrylic syrup, and a solvent-free urethane acrylate can be used.

[Anti-reflective film]

The antireflection film according to the present embodiment is an antireflection film in which an antiglare layer is laminated on at least one surface of the polyester film according to the present embodiment. The polyester film according to this embodiment can be used for an antireflection film.

The anti-glare layer may be formed by either a wet coating method or a dry coating method. In the anti-glare layer, JP 2014-059334, JP 2014-026122, JP 2014-016602, JP 2014-016476, JP 2014-041206, JP 2014- The anti-glare layer described in 032317, JP 2014-026123, and JP 2014-010316 can be used.

[Sensor film for touch panel]

The sensor film for touch panels according to the present embodiment is a sensor film for touch panels containing the polyester film according to the present embodiment. The polyester film according to this embodiment can be used for a sensor film for a touch panel. As for the sensor film for touch panels, it is preferable that a hard coat layer and a transparent conductive layer are laminated|stacked on a polyester film.

As a general method of forming the transparent conductive layer, there is a PVD (Physical Vapor Deposition) method such as a sputtering method, a vacuum vapor deposition method, an ion plating method, or a CVD (Chemical Vapor Deposition) method, a coating method, a printing method, and the like. In addition, the formation material of the transparent conductive layer is not particularly limited, and examples include indium-tin composite oxide (ITO), tin oxide, copper, silver, aluminum, nickel, chromium, etc., and other formation materials are formed by overlapping May be.

In addition, before forming the transparent conductive layer, an undercoat layer for improving transparency or optical properties may be provided. In addition, in order to improve adhesion, a metal layer made of a single metal element or an alloy of two or more metal elements may be provided between the undercoat layer and the polyester film. It is preferable to use a metal selected from the group consisting of silicon, titanium, tin and zinc for the metal layer.

[Image display device]

The image display device according to the present embodiment includes an image display element and a hard coat film according to the present embodiment, and a hard coat film is disposed on the outermost surface.

Examples of the image display device according to the present embodiment include an image display device such as a liquid crystal display (LCD), a plasma display panel, an electroluminescence display, and a cathode tube display device.

As a liquid crystal display device, TN (Twisted Nematic) type, STN (Super-Twisted Nematic) type, TSTN (Triple Super Twisted Nematic) type, multi-domain type, VA (Vertical Alignment) type, IPS (In Plane Switching) type, OCB (Optically Compensated Bend) type, etc. are mentioned.

In particular, the image display device includes a liquid crystal cell and a polarizing plate according to the present embodiment disposed on at least one surface of the liquid crystal cell, and a hard coat film according to the present embodiment is preferably a liquid crystal display device disposed on the outermost surface. Do. In this case, the image display element is a liquid crystal display element.

In the image display device according to the present embodiment, it is preferable that the image display element is an organic electroluminescence display element.

[Touch Panel]

The touch panel according to the present embodiment includes the hard coat film according to the present embodiment, and the hard coat film is disposed on the outermost surface.

The touch panel to which the hard coat film according to the present embodiment can be applied is not particularly limited, and can be appropriately selected depending on the purpose. For example, a surface type capacitive touch panel, a projection type capacitive touch panel, a resistive touch panel, and the like can be mentioned. Details will be described later as a resistive touch panel according to the present embodiment and a capacitive touch panel according to the present embodiment.

In addition, the touch panel includes a so-called touch sensor and a touch pad. The layer structure of the touch panel sensor electrode part in the touch panel is a bonding method in which two transparent electrodes are bonded, a method in which transparent electrodes are provided on both sides of a single substrate, a single-sided jumper or through-hole method, or a single-sided lamination method Any of them may be used. In addition, the projection type capacitive touch panel is more preferably AC (Alternating Current) driving than DC (Direct Current) driving, and more preferably a driving method in which the voltage application time to the electrodes is short.

(Resistive touch panel)

The resistive film type touch panel according to the present embodiment is a resistive film type touch panel including the hard coat film according to the present embodiment.

A resistive touch panel has a basic configuration in which conductive films of a pair of upper and lower substrates having a conductive film are opposed to each other through spacers. In addition, the configuration of the resistive touch panel is known, and in the present embodiment, a known technique can be applied without limitation.

(Capacitive touch panel)

The capacitive touch panel according to the present embodiment is a capacitive touch panel including the hard coat film according to the present embodiment.

As the method of the capacitive touch panel, a surface type capacitive type, a projection type capacitive type, and the like can be mentioned. The projection-type capacitive touch panel has a basic configuration in which an X-axis electrode and a Y-axis electrode orthogonal to the X-axis electrode are disposed through an insulator. As a specific aspect, an X electrode and a Y electrode are formed on different surfaces on a single substrate, an X electrode, an insulator layer, and a Y electrode are formed in this order on a single substrate, and a single substrate An aspect in which an X electrode is formed on the upper surface and a Y electrode is formed on another substrate (in this aspect, a configuration in which two substrates are bonded together is constituted by the above basic configuration), and the like. In addition, the configuration of the capacitive touch panel is known, and in this embodiment, a known technique can be applied without limitation.

Example

Hereinafter, the present disclosure will be described in more detail with reference to Examples and Comparative Examples. Materials, usage, ratios, treatment contents, treatment procedures, and the like shown in the following examples can be appropriately changed as long as they do not deviate from the spirit of the present disclosure. Therefore, the scope of the present disclosure is not limitedly interpreted by the specific examples shown below.

In addition, unless otherwise specified, "parts" and "ppm" are on a mass basis.

[Example 1]

<Synthesis of raw material polyester>

(Raw material polyester 1)

As shown below, using a direct esterification method in which terephthalic acid and ethylene glycol are directly reacted to distill water and esterify, and then polycondensate under reduced pressure, the raw material polyester 1 ( Sb catalyst system PET) was obtained.

(1) esterification reaction

4.7 tons of high purity terephthalic acid and 1.8 tons of ethylene glycol were mixed for 90 minutes to form a slurry, and continuously supplied to the first esterification reactor at a flow rate of 3800 kg/h. Further, an ethylene glycol solution of antimony trioxide was continuously supplied, and the reaction was carried out at a temperature of 250°C in a reaction tank, under stirring, and an average residence time of about 4.3 hours. At this time, antimony trioxide was continuously added so that the amount of Sb added was 150 ppm in terms of elements.

The reaction product was transferred to a second esterification reaction tank, and, under stirring, the reaction mixture was reacted at an internal temperature of 250°C for 1.2 hours at an average residence time of the reaction tank. To the second esterification reactor, an ethylene glycol solution of magnesium acetate and an ethylene glycol solution of trimethyl phosphate were continuously supplied so that the Mg addition amount and the P addition amount were 65 ppm and 35 ppm, respectively, in terms of elements.

(2) polycondensation reaction

The esterification reaction product obtained above was continuously supplied to the first polycondensation reactor, and under stirring, polycondensation at a reaction temperature of 270° C. and a pressure in the reactor of 20 torr (2.67×10 ⁻³ MPa) with an average residence time of about 1.8 hours. Made it.

In addition, it was transferred to the second polycondensation reaction tank, and under stirring in this reaction tank, the reaction was carried out under conditions of a residence time of about 1.2 hours at a ^{temperature in the reaction tank of 276°C and a pressure in the reaction tank of 5 torr (6.67×10 -4 MPa) (polycondensation).} Made it.

Subsequently, it is further transferred to a third polycondensation reaction tank, and in this reaction tank, reaction (polycondensation) under conditions of a residence time of 1.5 hours at a ^{temperature in the reaction tank of 278°C and a pressure in the reaction tank of 1.5 torr (2.0×10 -4 MPa)} Then, a reaction product (polyethylene terephthalate; PET) was obtained.

Next, the obtained reactant was discharged in cold water in a strand shape, and immediately cut to produce a polyester pellet "cross section: about 4 mm in long diameter, about 2 mm in short diameter, and about 3 mm in length".

The obtained polyester was IV=0.63. This polyester was used as the raw material polyester 1.

<Production of polyester film>

-Film forming process-

The raw material polyester 1 was dried to a moisture content of 20 ppm or less, and then put into hopper 1 of a single-screw kneading extruder 1 having a diameter of 50 mm. Raw material polyester 1 was melt|melted at 300 degreeC, and it extruded from a die through a gear pump and a filter (pore diameter 20 micrometers) under the following extrusion conditions.

As for the extrusion conditions of the molten resin, the molten resin was extruded from the die with the pressure fluctuation being 1% and the temperature distribution of the molten resin being 2%. Specifically, the back pressure was pressurized by 1% with respect to the average pressure in the barrel of the extruder, and the piping temperature of the extruder was made 2% higher than the average temperature in the barrel of the extruder.

The molten resin extruded from the die was extruded on a cooled cast drum set at a temperature of 25°C, and was brought into close contact with the cooled cast drum using an electrostatic application method. It peeled using the peeling roll arranged opposite to the cooling cast drum, and the unstretched polyester film 1 was obtained.

-Formation of easy adhesive layer-

The following compounds were mixed in the following ratio to prepare a coating liquid H1 for forming an easily adhesive layer.

(Coating solution H1 for easily bonding layer formation)

Polyester resin: (IC) 60 parts by mass

Acrylic resin: (II) 25 parts by mass

Melamine compound: (VIB) 10 parts by mass

Particles: (VII) 5 parts by mass

The details of the compound used for formation of the easily adhesive layer are shown below.

Polyester resin: (IC)

Sulfonic acid-based aqueous dispersion of polyester resin copolymerized with monomers of the following composition

Monomer composition: (acid component) terephthalic acid/isophthalic acid/5-sodium sulfoisophthalic acid// (diol component) ethylene glycol/1,4-butanediol/diethylene glycol=56/40/4 //70/20/10 (mol%)

Acrylic resin: (II)

Water dispersion of acrylic resin polymerized with monomers of the following composition

Emulsified polymer (emulsifier: anionic surfactant) of ethyl acrylate/n-butylacrylate/methyl methacrylate/N-methylolacrylamide/acrylic acid = 65/21/10/2/2 (mass%)

Melamine compound: (VIB) hexamethoxymethylmelamine

Particles: (VII) Silica sol with an average particle diameter of 150 nm (average particle diameter means the primary average particle diameter, that is, the average value of the primary particle diameter.)

-Application of an easily adhesive layer on one side of a polyester film-

By the bar coating method using a wire bar, the coating liquid H1 for forming an easily-adhesive layer was applied to one side of the unstretched polyester film 1 using a wire bar while adjusting the coating film thickness after stretching to be 65 nm.

-Horizontal stretching process-

The unstretched polyester film 1 was guided to a tenter (horizontal stretching machine), and horizontally stretched under the following method and conditions while holding the end of the film with a clip.

(Preheater)

It heated with hot air so that the surface temperature at the stretching start point might become 89 degreeC.

In addition, the surface temperature at the starting point of stretching is measured by a radiation thermometer (manufactured by Hayashi Denko, product number: RT61-2, used with an emissivity of 0.95) by measuring the position of the central part in the width direction of the film at the point where stretching is started did.

(Extension part)

While heating the preheated unstretched polyester film 1 with hot air, it was horizontally stretched in the width direction (TD) using a tenter under the following conditions.

In addition, the surface temperature at each draw ratio is measured by a radiation thermometer (manufactured by Hayashi Denko, product number: RT61-2, used with an emissivity of 0.95) by measuring the position of the central part in the width direction of the film at each draw ratio time point. did.

<condition>

・Horizontal draw ratio: 4.1 times

Surface temperature at the time of 2 times stretching: 90°C

Surface temperature at the point of 3 times stretching: 94°C

·Surface temperature at the end of stretching: 95°C

(Heat fixing government and heat mitigation department)

Subsequently, heat setting and thermal relaxation treatment were performed while hot air from an up-down direction was applied to the film with respect to the film, and the surface temperature of the polyester film was controlled in the following range.

<condition>

·Maximum surface temperature reached (heat setting temperature): 185℃

Thermal relaxation rate: MD 4%, TD 1.5%

(Cooling part)

Next, the film was cooled by applying cold air from the vertical direction to the film from the cold air jet nozzle. It cooled so that the surface temperature when the film was released from the clip of the tenter became 40 degreeC.

In addition, the surface temperature was measured with a radiation thermometer (manufactured by Hayashi Denko, product number: RT61-2, used with an emissivity of 0.95) at the position of the central portion in the width direction of the film.

(Recovery of film)

After cooling and release of the film from the clip, both ends of the polyester film were trimmed by 20 cm. The film width after trimming was 2 m. Thereafter, after performing uneven processing (knurling) with a width of 10 mm on both ends, a film having a tension of 18 kg/m and a length of 10000 m was wound up in a roll form.

In the manner described above, a polyester film of Example 1 having a thickness of 200 μm, wound in a roll form, was produced.

[Examples 2 to 11, 13, 14, and Comparative Examples 1 to 3, 5]

In Example 1, in the same manner as in Example 1, except that the conditions of the transverse stretching step, the easily adhesive layer, and the hard coat layer were changed as described in Table 1 below, the polyester film of each Example and Comparative Example Was prepared.

[Example 12, Comparative Example 4]

A polyester film of Example 12 was produced in the same manner as in Example 1 except that an easily adhesive layer was not provided.

Further, as described in Table 1 below, the conditions of the transverse stretching step and the film thickness were changed, and a polyester film of Comparative Example 4 was produced in the same manner as in Example 1 except that an easily adhesive layer was not further provided. In addition, in Comparative Example 4, a polyester film was prepared in a similar manner based on the description of Example 2 of JP 2012-230390 A.

[Film measurement result]

About the film obtained in each example, the following physical properties were measured. The measurement results are shown in Table 1 below.

<Thickness>

The thickness of the polyester film of each obtained Example and the comparative example was calculated|required as follows.

For the polyester films of each Example and Comparative Example, 50 points were sampled at equal intervals over 0.5 m in the vertically stretched direction (length direction) using a contact-type film thickness measuring system (manufactured by Anritsu Corporation), and additionally film After sampling 50 points at equal intervals (50 equal parts in the width direction) over the entire width of the film in the width direction (direction orthogonal to the length direction), the thickness of these 100 points was measured. The average thickness of these 100 points was calculated|required, and it was set as the thickness of a polyester film.

<Re, Rth, Re/Rth ratio>

For the films obtained in each example, Re and Rth were determined by the method described above. From the obtained Re and Rth, the Re/Rth ratio was calculated.

<Shear surface normal stress and shear surface yield stress>

For the polyester films of each of the obtained Examples and Comparative Examples, SAICAS-NN type (manufactured by Daipla Wintes Co., Ltd.) was used, and the shear surface normal stress and shear surface yield stress of 1 μm of the film surface layer were respectively described above. Measured by

From the obtained measured values, the average value of the shear plane normal stress A in the slow axis direction in the surface layer 1 μm and the shear plane normal stress B in the direction perpendicular to the slow axis direction in the film plane (fast axis direction) was calculated. In addition, TD is the slow axis direction of the film, and MD is the fast axis direction of the film.

[Production of hard coat film]

A coating liquid for forming a hard coat layer of the following composition was prepared.

Cyclomer M100: 40 parts by mass of 3,4-epoxycyclohexylmethyl methacrylate (manufactured by Daicel Corporation)

DPHA: KAYARD DPHA (manufactured by Nippon Kayaku Co., Ltd.) 55.4 parts by mass

-Irgacure127: 2.5 parts by mass of an alkylphenone-based photoinitiator (BASF (manufactured))

-Irgacure290: 2.0 parts by mass of a sulfonium salt-based cationic polymerization initiator (BASF (manufactured by BASF))

Wind unevenness inhibitor FP-1: 0.1 parts by mass of a fluorinated compound having the following structure

100 parts by mass of solvent 1 MEK

Solvent 2 MIBK 50 parts by mass

[Formula 14]

The uniaxially stretched polyester films of each Example and Comparative Example wound up in a roll form were unwound, and as a post-process, the coating liquid for forming a hard coat layer was applied by the following method.

A coating liquid for forming a hard coat layer is applied to one side of the film (on the side of the easily-adhesive layer when an easily-adhesive layer is provided) by a die-coating method using a slot die described in Example 1 of JP 2006-122889, a conveyance speed of 30 m/min. It was applied under the conditions of. After drying at 60° C. for 150 seconds, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% and 160 W/cm under nitrogen purge, illuminance 400 mW/cm ² , irradiation dose 500 mJ/cm ² UV rays were irradiated to cure the coating layer (hard coat layer) and wind up.

<Film thickness of the hard coat layer>

When a polyester film obtained in Examples or Comparative Examples other than Example 9 is used, the thickness of the hard coat layer is 22 μm, and when the polyester film obtained in Example 9 is used, the thickness of the hard coat layer is 5 μm. I did it.

In addition, the film thickness of the hard coat layer was calculated by measuring the film thickness of the hard coat film produced by a contact-type film thickness meter, and subtracting the thickness of the polyester film measured in the same manner as it.

[evaluation]

About the hard coat film obtained in each Example and a comparative example, the following evaluation was performed. The evaluation results are shown in Table 1 below.

<Punching evaluation>

The hard coat film was punched 10 times, and the crack/peel condition of the hard coat film in the punched cross section was evaluated according to the following criteria.

A: No cracking/peeling at all

B: Crack/peel only occurs once

C: cracking/peeling occurs only 2-3 times

D: cracking/peeling occurred more than 4 times

<Surface deformation evaluation>

The concave portion when the hard coat film surface (the hard coat layer side) ^{was pressed in with a force of 10 N/mm 2 with} a stylus was observed, and evaluated according to the following criteria.

A: No recesses occur at all

B: The concave part is unknown to the naked eye, but can be recognized when observed with a microscope

C: The concave part can be seen slightly with the naked eye

D: The recess can be clearly seen with the naked eye

<Visibility evaluation>

Between the polarizing plates provided in the cross nicol, the hard coat film was placed so that its orientation angle was inclined by 45° with respect to the absorption axis of the polarizing plate, and the LED backlight was illuminated from the rear to evaluate the visibility according to the following criteria.

A: No rainbow unevenness is seen

B: The rainbow non-uniformity is hardly seen

C: A little rainbow unevenness is visible, but it is acceptable

D: The rainbow unevenness is strong

[Table 1]

The meaning of the symbols in Table 1 is as follows.

DPHA: KAYARD DPHA (made by Nippon Kayaku Co., Ltd.)

3,4-epoxy CHMA: 3,4-epoxycyclohexylmethylacrylate

3,4-epoxy CHMM: 3,4-epoxycyclohexylmethylmethacrylate

IRG127: Irgacure127 (alkylphenone photopolymerization initiator, manufactured by BASF)

IRG290: Irgacure290 (sulfonium salt-based cationic polymerization initiator, manufactured by BASF)

RS-90: (antifouling agent, manufactured by DIC Corporation)

As is clear from Table 1, in the hard coat film of the example, the cracking and peeling of the hard coat layer and the occurrence of the recess were all suppressed compared to the hard coat film of the comparative example.

As for the indication of Japanese Patent Application No. 2016-026351 for which it applied on February 15, 2016, the whole is incorporated in this specification by reference.

All documents, patent applications, and technical standards described in this specification are specifically incorporated by reference, and to the same extent as when individually recorded, the individual documents, patent applications, and technical standards are incorporated by reference in this specification. do.

10 cutting blades
12 polyester film
20 clips (grasp member)

Claims (22)

The thickness is 80μm~500μm,
The average value of the shear plane normal stress A in the slow axis direction in the surface layer 1 μm and the shear plane normal stress B in the direction orthogonal to the slow axis direction in the film plane is 30 MPa to 100 MPa,
Has an easily adhesive layer on at least one side,
The thickness of the adhesive layer is 30nm ~ 300nm, polyester film. The method according to claim 1,
Polyester film for a base film of a hard coat film. The method according to claim 1,
Polyester film, which is a uniaxially oriented polyester film. The thickness is 40μm~500μm,
The average value of the shear plane normal stress A in the slow axis direction in the surface layer 1 μm and the shear plane normal stress B in the direction orthogonal to the slow axis direction in the film plane is 30 MPa to 100 MPa,
The polyester film in which the retardation Re in the film plane at a measurement wavelength of 589 nm is 14000 nm to 500,000 nm. The method according to claim 1,
The polyester film, wherein the average value of the shear surface yield stress in the slow axis direction in 1 μm of the surface layer of the polyester film and the shear surface yield stress in the direction orthogonal to the slow axis direction within the film surface is 20 MPa to 60 MPa. The method according to claim 1,
The ratio of the shear surface normal stress A to the shear surface normal stress B is 1.1 to 2.0, a polyester film. The method according to claim 1,
The polyester film, wherein the ratio of the retardation Re in the film plane to the retardation Rth in the film thickness direction at a measurement wavelength of 589 nm of the polyester film is 0.6 to 1.2. A base film comprising the polyester film according to any one of claims 1 to 7,
A hard coat film having a hard coat layer laminated on at least one side of the base film. The method of claim 8,
The hard coat film, wherein the thickness of the hard coat layer is 5 μm or more. Polyester film having a thickness of 40 μm to 500 μm and an average value of the shear surface normal stress A in the slow axis direction in the surface layer 1 μm and the shear surface normal stress B in the direction orthogonal to the slow axis direction in the film plane of 30 MPa to 100 MPa And a base film comprising a,
As a hard coat film having a hard coat layer laminated on at least one side of the base film,
The hard coat layer,
It contains at least the structure derived from the following a), the structure derived from the following b), and the following c) and d)
When the hard coat layer makes the total solid content of the hard coat layer 100% by mass, the structure derived from a) is 15% by mass to 70% by mass, and the structure derived from b) is 25% by mass to 80% by mass. , A hard coat film containing 0.1% by mass to 10% by mass of the following c), and 0.1% by mass to 10% by mass of the following d).
a) A compound having a group containing one alicyclic epoxy group and one ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less
b) a compound having a group containing three or more ethylenically unsaturated double bonds in the molecule
c) radical polymerization initiator
d) cationic polymerization initiator An image display device comprising an image display element and a hard coat film according to claim 8, wherein the hard coat film is disposed on an outermost surface. A touch panel comprising the hard coat film according to claim 8, wherein the hard coat film is disposed on the outermost surface. Using a transverse stretching device having a plurality of clips each running along a pair of rails provided on both sides of the film conveyance path,
A preheating step of preheating an unstretched or vertically stretched polyester film at a temperature rising rate of 600°C/min or less, and
Transverse stretching is performed in a direction orthogonal to the film conveying path while both edges of the preheated polyester film are gripped with the plurality of clips, and the polyester film from the start of the transverse stretching to the end of the transverse stretching By gradually increasing the surface temperature of, the surface temperature at the start of the transverse stretching is 80°C or more and 95°C or less, and the surface temperature at the end of the transverse stretching is controlled to 90°C or more and 105°C or less, and the transverse draw ratio A transverse stretching process that controls in the range of 3.3 times or more and 4.8 times or less,
And a heat setting step of heat setting by heating the polyester film after the transverse stretching step to a maximum temperature in the transverse stretching device,
The thickness is 80 μm to 500 μm, and the average value of the shear plane normal stress A in the slow axis direction in the surface layer 1 μm and the shear plane normal stress B in the direction orthogonal to the slow axis direction in the film plane is 30 MPa to 100 MPa, and at least one side Has an easily adhesive layer, the thickness of the easily adhesive layer is 30nm ~ 300nm, polyester film, or
The thickness is 40 μm to 500 μm, and the average value of the shear surface normal stress A in the slow axis direction in the surface layer 1 μm and the shear surface normal stress B in the direction orthogonal to the slow axis direction in the film surface is 30 MPa to 100 MPa, and the measurement wavelength Polyester film with retardation Re in the film plane at 589 nm from 14000 nm to 500,000 nm
Method for producing a polyester film to produce. The method of claim 13,
In the transverse stretching step, the surface temperature is gradually increased at a temperature increase rate of 60° C./min or less, so that the surface temperature is 80° C. or more and 92° C. or less when the transverse stretching ratio is in the range of 1 to 2 times. in,
The surface temperature when the transverse stretching ratio is in the range of 2 times or more and less than 3 times is 85° C. or more and 97° C. or less, and
A method for producing a polyester film, wherein the surface temperature is controlled to 90°C or more and 102°C or less when the transverse draw ratio is in a range of 3 or more. The method of claim 13,
The rate of temperature increase of the surface temperature of the polyester film from the end of the transverse stretching step to reaching the maximum temperature in the heat setting step is controlled to 1000° C./min or less,
Polyester controlling the maximum attainable surface temperature of the polyester film in the heat setting step to 130°C or more and 230°C or less, and controlling the time when the surface temperature of the polyester film exceeds 130°C to 180 seconds or less Method of making the film. The method of claim 13,
Heating the polyester film after the heat setting step, further comprising a heat relaxation step of reducing the length of the polyester film at least in the transverse direction, the method of producing a polyester film. A process of producing a polyester film by the method for producing a polyester film according to any one of claims 13 to 16, and
A method of manufacturing a hard coat film having a step of laminating a hard coat layer on at least one side of the polyester film. The method of claim 10,
The hard coat film wherein the polyester film is a uniaxially oriented polyester film. The method of claim 10,
A hard coat film having a retardation Re of 4000 nm to 500,000 nm in the film plane at a measurement wavelength of 589 nm of the polyester film. The method of claim 10,
A hard coat film in which the average value of the shear surface yield stress in the slow axis direction in 1 μm of the surface layer of the polyester film and the shear surface yield stress in the direction orthogonal to the slow axis direction within the film surface is 20 MPa to 60 MPa. The method of claim 10,
The hard coat film in which the ratio of the shear surface normal stress A to the shear surface normal stress B of the polyester film is 1.1 to 2.0. The method of claim 10,
The hard coat film in which the ratio of the retardation Re in the film plane to the retardation Rth in the film thickness direction at a measurement wavelength of 589 nm of the polyester film is 0.6 to 1.2.

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