JPWO2017141680A1 - Polyester film and manufacturing method thereof, hard coat film and manufacturing method thereof, image display device and touch panel - Google Patents

Abstract

Provided is a polyester film in which dents hardly occur even when a load is locally applied in the thickness direction of the film.
The polyester film has a thickness of 40 to 500 μm, and the average value of the shear plane normal stress A in the slow axis direction in the surface layer of 1 μm and the shear plane normal stress B in the direction perpendicular to the slow axis direction in the film plane is 30. ~ 100 MPa.

Description

  The present disclosure relates to a polyester film and a manufacturing method thereof, a hard coat film and a manufacturing method thereof, an image display device, and a touch panel.

  In applications where chemically tempered glass has been used, with the progress of technology for increasing the hardness of hard coat materials, glass replacement for hard coat films obtained by laminating a hard coat layer on a base film has attracted attention. An example of the hard coat film is a protective film on the outermost surface of an image display device such as a touch panel.

  For example, Patent Document 1 states that “a laminated base material in which a functional layer is formed on one surface to form a laminated body,
A light-transmitting substrate having in-plane birefringence;
A refractive index adjusting layer laminated with a light transmissive substrate and having in-plane birefringence, the refractive index adjusting layer being positioned between the light transmissive substrate and the functional layer,
Refractive index n in the slow axis direction, which is the direction with the highest refractive index in the plane of the light transmissive substrate _1xThe refractive index n of the refractive index adjusting layer in the direction parallel to the slow axis direction of the light-transmitting substrate_2xAnd the refractive index n of the functional layer in the direction parallel to the slow axis direction of the light-transmitting substrate._3xBut,
n_1x<N_2x<N_3xOr n_1x> N_2x> N_3x
Satisfy the relationship
Refractive index n in the fast axis direction perpendicular to the slow axis direction of the light transmissive substrate_1yThe refractive index n of the refractive index adjusting layer in the direction parallel to the fast axis direction of the light-transmitting substrate_2yAnd the refractive index n of the functional layer in a direction parallel to the fast axis direction of the light-transmitting substrate._3yBut,
n_1y<N_2y<N_3yOr n_1y> N_2y> N_3y
A laminated base material that satisfies the following relationship is disclosed.

  Patent Document 2 states that “a coating layer is formed on both surfaces of a multilayer polyester film having a laminated structure of at least three layers, the polyester layers of both outermost layers have a higher softening point than the intermediate layer, and the surface of one coating layer A surface protective film comprising a pressure-sensitive adhesive layer, wherein the coating layer is formed from a coating solution containing 70% by weight or more of a crosslinking agent with respect to the nonvolatile component " Yes.

In Patent Document 3, “uniaxially oriented polyester film having the following characteristics:
(1) The film surface has 1 or less scratches per 1 m ^{2 in} height difference, and 20 or less scratches per 1 m ^{2 in} height difference of 0.3 μm or more and less than 1 μm,
(2) The film has 1 or less foreign matter having a major axis of 100 μm or more per 1 m ² ,
(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 orientation principal axis of the film measured with a microwave transmission type molecular orientation meter The distortion is within 7 degrees. Is disclosed.

  Patent Document 4 states that “a uniaxially oriented coextruded laminated film composed of at least three polyester layers of A layer, B layer and C layer, and the outermost layer A and C layers have an average particle size of 0. The layer B, which is a substantially homogenous polyester containing 0.01 to 0.5% by weight of inert particles of 1 to 5.0 μm, is a dicarboxylic acid component, aliphatic or alicyclic A diol component and a polyalkylene ether glycol component having a number average molecular weight of 300 to 4000 as a main constituent component, comprising a polyester containing 10 to 35% by weight of a polyalkylene ether glycol component, and a thickness ratio in the total film thickness of the B layer Is a 65% to 95% uniaxially oriented laminated polyester film ”.

In Patent Document 5, “a polyester film satisfying 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 full width arc of the film, C _CT [unit: m] represents the value of the semicircular arc at the center position in the film width direction, and W [unit: m] represents the film width. L [unit: m] represents the film length when measuring full-width arcs and half-cut arcs. Is disclosed.

JP2013-257550A JP-A-2015-128897 JP 2005-2220 A JP 2004-351788 A International Publication No. 2015/46122

  In the films disclosed in Patent Documents 1 to 5, the shear plane normal stress is insufficient, and a dent is likely to occur when a load is locally applied in the thickness direction of the film. It is considered that when a hard coat film obtained by laminating a hard coat layer on these films and punching is performed, the hard coat layer is easily cracked or peeled off.

An object of the present disclosure is to provide a polyester film that hardly causes a dent even when a load is locally applied in the thickness direction of the film, and a method for manufacturing the polyester film.
In addition, the present disclosure provides a hard coat film in which cracking and peeling of the hard coat layer are unlikely to occur when a hard coat film in which a hard coat layer is laminated on a polyester film is produced and punched, and a method for producing the same. With the goal.
Furthermore, an object of the present disclosure is to provide an image display device and a touch panel in which a reduction in visibility due to rainbow unevenness is suppressed even when a load is locally applied to the display screen.

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

<1> The thickness is 40 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 perpendicular to the slow axis direction in the film plane is 30 to A polyester film that is 100 MPa.
<2> The polyester film according to <1>, which is for a base film of a hard coat film.
<3> The polyester film according to <1> or <2>, which is a uniaxially oriented polyester film.
<4> The polyester film according to any one of <1> to <3>, wherein the in-plane retardation Re at a measurement wavelength of 589 nm of the polyester film is 4000 to 50000 nm.
<5> The average value of the shear plane yield stress in the slow axis direction in the surface layer of 1 μm of the polyester film and the shear plane yield stress in the direction perpendicular to the slow axis direction in the film plane is 20 to 60 MPa <1> to The polyester film as described in any one of <4>.
<6> The polyester film according to any one of <1> to <5>, wherein a ratio of the shear plane normal stress A to the shear plane normal stress B is 1.1 to 2.0.
<7> 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. Any one of <1> to <6> The polyester film as described.
<8> A base film comprising the polyester film according to any one of <1> to <7>,
A hard coat layer laminated on at least one side of the base film;
Hard coat film having
<9> The hard coat film according to <8>, wherein the thickness of the hard coat layer is 5 μm or more.
<10> Hard coat layer
At least a structure derived from a) below, a structure derived from b) below, c) and d) below,
When the hard coat layer has a total solid content of the hard coat layer of 100% by mass, the structure derived from the following a) is 15 to 70% by mass, the structure derived from the following b) is 25 to 80% by mass, and the following c) The hard coat film as described in <8> or <9> containing 0.1-10 mass% and 0.1-10 mass% of following d).
a) a compound having one alicyclic epoxy group and one group containing an ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less; b) three or more ethylenic groups in the molecule. A compound having a group containing a saturated double bond c) a radical polymerization initiator d) a cationic polymerization initiator <11> an image display device and a hard coat film according to any one of <8> to <10>, An image display device in which a hard coat film is disposed on the outermost surface.
<12> A touch panel comprising the hard coat film according to any one of <8> to <10>, wherein the hard coat film is disposed on the outermost surface.
<13> Using a lateral stretching apparatus including a plurality of clips respectively traveling along a pair of rails installed on both sides of the film conveyance path,
A preheating step of preheating an unstretched or longitudinally stretched polyester film at a heating rate of 600 ° C./min or less;
In the state where both edges of the preheated polyester film are held by a plurality of clips, the film is stretched in the direction perpendicular to the film conveyance 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. The surface temperature at the start of the transverse stretching is controlled to 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. A transverse stretching step for controlling the range to be less than double,
A heat setting step of heat-setting the polyester film after the transverse drawing step by heating to the maximum temperature in the transverse drawing apparatus,
The manufacturing method of the polyester film which manufactures the polyester film whose thickness is 40-500 micrometers.
<14> In the transverse stretching step, the surface temperature is gradually increased at a heating rate of 60 ° C./min or less,
The surface temperature when the transverse draw ratio is in the range of 1 to less than 2 times is 80 to 92 ° C.,
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 and 97 ° C or less, and
<13> The method for producing a polyester film according to <13>, wherein the surface temperature when the transverse draw ratio is in the range of 3 times or more is controlled to 90 ° C. or higher and 102 ° C. or lower.
<15> The rate of temperature increase of the surface temperature of the polyester film from the end of the transverse stretching step to the maximum temperature in the heat setting step is controlled to 1000 ° C./min or less,
<13> or <14>, wherein the maximum surface temperature of the polyester film in the heat setting step is controlled to 130 ° C. or more and 230 ° C. or less, and the time that the surface temperature of the polyester film exceeds 130 ° C. is controlled to 180 seconds or less. A method for producing a polyester film.
<16> The polyester film according to any one of <13> to <15>, further comprising a thermal relaxation step of heating the polyester film after the heat setting step and shrinking at least the length of the polyester film in the lateral direction. Manufacturing method.
<17> The process of manufacturing a polyester film with the manufacturing method of the polyester film as described in any one of <13>-<16>,
Laminating a hard coat layer on at least one side of the polyester film;
The manufacturing method of the hard coat film which has this.

According to the present disclosure, there is provided a polyester film that hardly causes a dent even when a load is locally applied in the thickness direction of the film, and a method for manufacturing the polyester film.
In addition, according to the present disclosure, a hard coat film in which a hard coat layer is hardly cracked and peeled when a hard coat film in which a hard coat layer is laminated on a polyester film is produced and punched, and a method for producing the same are provided. Is done.
Furthermore, according to the present disclosure, there is provided an image display device and a touch panel in which a reduction in visibility due to rainbow unevenness is suppressed even when a load is locally applied to the display screen.

It is a perspective view which shows an example of the cutting blade used for the measuring method of the shear plane normal stress of a film surface layer, and a shear plane yield stress. It is the schematic explaining the measuring method of the shear surface normal stress of a film surface layer, and a shear surface yield stress. It is the schematic which shows an example of a structure of a horizontal extending | stretching apparatus.

  In the following, the present disclosure will be described in detail. The description of the constituent elements described below may be made based on representative embodiments or specific examples, but the present disclosure is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. Moreover, when the unit is attached | subjected to one of the numerical value described before and behind "-", it means that it is the same unit in the whole 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 with the shear plane normal stress B in the orthogonal direction is 30 to 100 MPa.
Here, the “slow axis direction” of the film is a direction in which the refractive index becomes maximum 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”.
Although the manufacturing method of the polyester film which concerns on this embodiment is explained in full detail behind, for example, after melt-extruding a polyester resin composition in a film form, it conveys using a roll etc., At least the conveyance direction (the length of a film) of a film When a polyester film is produced by stretching in a direction orthogonal to the direction (also referred to as the direction or longitudinal direction) (also referred to as the width direction or lateral direction of the film), the width direction of the film is usually the slow axis direction. In addition, when manufacturing a polyester film as mentioned above, the conveyance direction of a film may be called MD (Machine Direction), and the direction orthogonal to the conveyance direction of a film may be called TD (Transverse Direction).

<Characteristics of polyester film>
(Thickness)
The thickness of the polyester film according to this embodiment is 40 to 500 μm.
If 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. If it is 500 μm or less, the rigidity is not too strong, and the punching and handling properties of the film are good.
From this viewpoint, the thickness of the polyester film according to this 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, for example, using a contact film thickness meter, sampling 50 points each in the slow axis direction of the film and in the direction perpendicular to the slow axis direction in the film plane, The average thickness of the measured values of the thickness at these points is determined and taken as the thickness of the polyester film.

(Shear plane normal stress)
The polyester film according to the present embodiment has an average value of the shear plane normal stress A in the slow axis direction in the surface layer of 1 μm and the shear plane normal stress B in the direction perpendicular to the slow axis direction in the film plane (hereinafter referred to as “surface layer”). It may be referred to as “average shear plane normal stress”)) is 30 to 100 MPa. Here, “surface layer of 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 normal stress in the surface layer of 1 μm is 30 MPa or more, when a hard coat layer is laminated on the polyester film to form a hard coat film, the film is hardly dented and is not easily formed, and is 100 MPa or less. When it is made into a hard-coat film, it is hard to produce a crack or peeling in a hard-coat layer.
From this viewpoint, the surface layer average shear plane normal stress of the polyester film according to this embodiment is preferably 40 to 90 MPa, and more preferably 50 to 80 MPa.

In the polyester film according to this embodiment, the ratio (A / B) of the shear plane normal stress A to the shear plane normal stress B is preferably 1.1 to 2.0.
If the ratio A / B of 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 if it is 2.0 or less. When a hard coat layer is laminated on a polyester film to form a hard coat film, the hard coat layer is hardly cracked or peeled off.
From this 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 further preferably 1.3 to 1.8.

(Shear surface yield stress)
The polyester film according to this embodiment has an average value of the shear surface yield stress in the slow axis direction at the surface layer of 1 μm and the shear surface yield stress in the direction perpendicular to the slow axis direction in the film plane (hereinafter referred to as “surface layer average stress”). It may be referred to as “cross-sectional yield stress”.) Is preferably 20 to 60 MPa. If the surface layer average shear surface yield stress of the polyester film according to the present embodiment is 20 MPa or more, the film has dents even when the hard coat layer is laminated on the polyester film to form a hard coat film with a strong force. If it is 60 MPa or less, cracking or peeling is unlikely to occur in the hard coat layer when the hard coat film is formed.
From this 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 the shear surface normal stress and the shear surface yield stress of the film surface layer in the present embodiment will be described. 1 and 2 are schematic diagrams for explaining a method for measuring shear plane normal stress and shear plane yield stress of a film surface layer. The measuring device, measurement conditions, and shear surface normal stress and shear surface yield stress calculation methods are as follows.

(1) Measuring apparatus The SAICAS (Surface And Interfacial Cutting Analysis System) -NN type (manufactured by Daipura Wintes Co., Ltd.) is used to measure the shear surface normal stress and shear surface yield stress of the film surface layer in this embodiment. SAICAS can control the cutting edge speed and monitor the vertical force Fv and horizontal force F _H applied to the cutting edge 10 and the vertical displacement d of the cutting edge.

(2) Measurement conditions First, the rake angle α and the rake angle (cutting angle) γ of the cutting edge 10 with respect to the surface of the film 12 are set to predetermined angles, respectively, and cut into the inside from the film surface by the cutting edge (FIG. 1A). ).
A shear fracture occurs due to the cutting with the cutting blade 10, and the cutting force is monitored (FIG. 1B).
The film 12 is cut to a depth of 1 μm on the surface layer and the stress (film strength) acting on the shear surface is evaluated (FIG. 1C).
Here, the measurement conditions are as follows.
Cutting speed: horizontal speed 100 nm / s, vertical speed 10 nm / s
・ Blade width: 0.1 mm
・ Rake angle α: 20 °
・ Cutting angle γ: 10 °
・ Blade type: Diamond cutting edge ・ Direction: Measured in each of slow axis direction and fast axis direction (TD, MD) ・ Measured 3 points at 10 mm intervals along each direction, and average value in each direction And

(3) Calculation of shear plane normal stress and shear plane yield stress FIG. 2 shows a sample (polyester film) 12 with a cutting angle γ from (A) to (C) in FIG. Indicates the direction of the force that acts when cutting. Force F _N acting on the force F _S perpendicular acting in parallel to the sample shear plane A-B is determined by the following equation (1) using in each horizontal force monitoring F _H and the vertical force F _V, the shear angle φ It is done.

Formula (1)

The stress (σ _s ; shear plane normal stress) acting perpendicularly to the shear plane (plane indicated by the dotted line AB in FIG. 2) (τ _s ; shear plane yield stress) and F _S and F _N the obtained as respectively following equation was divided by the area a _s of the shear plane (2). Note that b is the blade width and d is the cutting depth (vertical displacement).

Formula (2)

  The shear angle φ is obtained by the following equation (3) using the rake angle α and the friction angle β.

Formula (3)

That is, the depth distribution of the shear surface yield stress τ _s or the shear surface normal stress σ _s can be calculated by obtaining the shear angle α from the horizontal force F _H and the vertical force F _V at each depth.

  The polyester film according to this embodiment is preferably a uniaxially oriented polyester film. A polyester film having the above-described thickness and shear plane normal stress is easily obtained by transversely stretching and heat-fixing an unstretched polyester film formed by melt film formation or solution film formation by a method described later.

-Re (Retardation in the film plane)-
The polyester film according to the present embodiment preferably has an in-plane retardation Re of 4000 to 50000 nm at a measurement wavelength of 589 nm.
If Re of the polyester film according to this embodiment is 4000 nm or more, rainbow unevenness is difficult to be visually recognized, and if it is 50000 nm or less, the necessary film thickness does not become too thick and it is suppressed that the rigidity is too strong, and handling is easy. It becomes.
From this viewpoint, Re at a measurement wavelength of 589 nm of the polyester film according to this embodiment is more preferably 5000 to 40000 nm, and further preferably 7000 to 33000 nm.

-Re / Rth-
In the polyester film according to this embodiment, the ratio of the in-plane retardation Re to the retardation Rth in the film thickness direction (Re / Rth) at a measurement wavelength of 589 nm is preferably 0.6 to 1.2. .
If the Re / Rth at the measurement wavelength of 589 nm of the polyester film according to this embodiment is 0.6 or more, rainbow unevenness is hardly visible, and if it is 1.2 or less, the film is difficult to become brittle.
From this viewpoint, the Re / Rth of the polyester film according to this embodiment is more preferably 0.7 to 1.15, and still more preferably 0.8 to 1.1.

  The retardation Rth in the thickness direction at a measurement wavelength of 589 nm of the polyester film according to this embodiment is preferably 3000 to 80000 nm, more preferably 4000 to 60000 nm, and still more preferably 6000 to 40000 nm. If Rth is 3000 nm or more, it is easy to make a film, and if it is 80000 nm or less, when a 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, rainbow unevenness appears on the screen. It is less likely to occur and is preferable.

Rainbow irregularity can also be reduced by setting an appropriate value for the Nz value representing the relationship between Re and Rth, and the absolute value of the Nz value is 2.0 or less due to the effect of reducing the rainbow irregularity and manufacturing suitability. Is preferably 0.5 to 2.0, and more preferably 0.5 to 1.5.
Since rainbow unevenness is generated by incident light, it is usually observed during white display.
The in-plane retardation Re of the polyester film according to this embodiment is represented by the following formula (4).

Formula (4): Re = (nx−ny) × y₁
  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 perpendicular to the in-plane slow axis direction) of the polyester film, and y ₁Is the thickness of the polyester film.

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

Formula (5): Rth = {(nx + ny) / 2−nz} × y ₁
Here, nz is the refractive index in the thickness direction of the polyester film.

  The Nz value of the polyester film is represented by the following formula.

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

In this specification, Re, Rth, and Nz at a wavelength λnm can be measured as follows.
Using two polarizing plates, the orientation axis direction (slow axis direction and fast axis direction) of the polyester film is obtained, and a 4 cm × 2 cm rectangle is cut out so that the orientation axis directions are orthogonal to each other, and used as a measurement sample. . For this sample, the biaxial refractive index (Nx, Ny) perpendicular to each other and the refractive index (Nz) in the thickness direction were determined by an Abbe refractometer (NAGO-4T, measurement wavelength 589 nm, manufactured by Atago Co., Ltd.). The absolute value of the refractive index difference (| Nx−Ny |) was defined as the refractive index anisotropy (ΔNxy). The thickness y ₁ (nm) of the polyester film was measured using an electric micrometer (manufactured by Fine Reef, Millitron 1245D), and the unit was converted to nm. Measured Nx, Ny, Nz, Re from the value of _{y 1,} Rth, Nz was calculated.

The above Re and Rth can be adjusted by the type of polyester resin used in the film, the amount of the polyester resin and the additive, the addition of the retardation developer, the film thickness, the film stretching direction and the stretching ratio, and the like. .
Although there is no restriction | limiting in particular in the method of controlling Re and Re / Rth of the polyester film which concerns on this embodiment in each range, For example, it can achieve by the extending | stretching method.

<Constituent material, layer structure and surface treatment of polyester film>
The polyester film according to the present embodiment includes a polyester resin. The mass ratio of the polyester resin in the entire film is usually 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more.
The polyester film according to the present embodiment may be a single layer film having a polyester resin as a main component, or may be a multilayer film having at least one layer having a polyester resin as a main component.
Moreover, the polyester film which concerns on this embodiment may be surface-treated on both surfaces 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 vapor deposition of polymer, metal or the like.

The polyester film according to the present embodiment may have an easy adhesion layer on at least one side.
30-300 nm is preferable, as for the thickness of the easily bonding layer contained in the polyester film which concerns on this embodiment, 40-200 nm is more preferable, and 50-150 nm is still more preferable.
If the thickness of an easily bonding layer is 30 nm or more, the cushion effect by an easily bonding layer will be easy to be acquired, and it will be suppressed that a shear plane normal stress and a shear plane yield stress rise too much. Moreover, if the thickness of an easily bonding layer is 300 nm or less, the cushioning effect of an easily bonding layer is not too strong, and it is suppressed that a shear plane normal stress and a shear plane yield stress fall too much.

More preferably, the easy-adhesion layer contains particles, and the height at which the particles protrude from the surface of the easy-adhesion layer is equal to or greater than the film thickness of the easy-adhesion layer.
The height at which the particles protrude from the surface of the easy adhesion layer is an average value at 5 points in the 1 mm square easy adhesion layer.
When the particle protruding from the surface of the easy-adhesive layer is less than the film thickness of the easy-adhesive layer (preferably, the coating layer), the slipperiness decreases and wrinkles are likely to occur. Tend.
The type of particles is not particularly limited, and specific examples include particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, titanium oxide, and zirconium oxide. Of these, silica, aluminum oxide, titanium oxide, and zirconium oxide are preferable. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like.
The particle diameter is preferably such that the height at which the particles protrude from the surface of the easy adhesion layer is equal to or greater than the film thickness of the easy adhesion layer. It is preferable to use particles adjusted with the primary average particle diameter, but as a result, the particles may be aggregated so that the height at which the particles protrude from the surface of the easy-adhesion layer is equal to or greater than the film thickness of the easy-adhesion layer. . In the case of agglomerated particles, the height at which the particles protrude from the surface of the easy adhesion layer can be confirmed by measuring the secondary average particle diameter.

(1-1) Polyester resin As a polyester resin contained in the polyester film according to the present embodiment, for example, a polyester resin having a composition of [0042] of WO2012 / 157762 is preferably used.
Specific examples of the polyester resin include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polycyclohexanedimethylene terephthalate (PCT). However, PET and PEN are preferable because of cost and heat resistance. More preferably, PET is more preferable. PEN tends to have a small Re / Rth.
As the polyester resin, polyethylene terephthalate is most preferable, but polyethylene naphthalate can also be preferably used. For example, polyethylene naphthalate described in JP-A-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 all repeating units are preferably ethylene terephthalate. The structural unit derived from other copolymerization components may be included. Other copolymer components include 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, 1,4-dicarboxycyclohexane, propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene Examples thereof include diol components such as glycol and polytetramethylene glycol. These dicarboxylic acid components and diol components can be used in combination of two or more if necessary. In addition, an oxycarboxylic acid such as p-oxybenzoic acid can be used in combination with the carboxylic acid component or the diol component. As another copolymer component, a dicarboxylic acid component and / or a diol component containing a small amount of an amide bond, a urethane bond, an ether bond, a carbonate bond, or the like may be used.
The production method of polyethylene terephthalate includes terephthalic acid and ethylene glycol, so-called direct polymerization method in which other dicarboxylic acids and / or other diols are directly reacted as necessary, dimethyl ester of terephthalic acid and ethylene glycol, if necessary Any production method such as a so-called transesterification method in which a dimethyl ester of another dicarboxylic acid and / or another 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. Hereinafter, it is more preferably 0.54 or more and 0.7 or less. In order to make such IV, when synthesizing a polyester resin, in addition to the melt polymerization described later, solid phase polymerization may be used in combination.

(1-2-2) Acetaldehyde content The polyester resin preferably has an acetaldehyde content of 50 ppm or less. More preferably, it is 40 ppm or less, Most preferably, it is 30 ppm or less. Acetaldehyde easily causes a condensation reaction between acetaldehydes, and water is generated as a side reaction product, which may cause hydrolysis of the polyester. The lower limit of the acetaldehyde content is practically about 1 ppm. In order to make the acetaldehyde content within the above range, keep the oxygen concentration in each step such as melt polymerization and solid phase polymerization at the time of resin production, keep the oxygen concentration at the time of resin storage and drying low, film Adopt methods such as lowering the heat history applied to the resin with an extruder, melt piping, die, etc. at the time of manufacture, and avoiding strong shearing locally due to the screw configuration of the extruder when melting. I can do it.

(1-3) Catalyst For the polymerization of the polyester resin, Sb, Ge, Ti and / or Al-based catalyst is used, preferably Sb, Ti and / or Al-based catalyst, more preferably Al-based catalyst. .
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 for Re to be expressed than when other catalysts (for example, Sb or Ti) are used, and PET can be thinned. In other words, the use of an Al-based catalyst means that the orientation is easier. This is presumed to be due to the following reasons.
The Al-based catalyst has a lower reactivity (polymerization activity) than the Sb-based catalyst or Ti-based catalyst, and thus the reaction is mild, and a by-product (diethylene glycol unit: DEG) is hardly generated.
As a result, the regularity of PET increases, and it is easy to align and to express Re.
(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). The contents described in these publications are incorporated herein by reference.
Although there is no restriction | limiting in particular as a method of manufacturing a polyester resin by superposition | polymerization using an Al type catalyst, Specifically, [0091]-[0094] of WO2012 / 008488 ([0144] of US2013 / 0112271) To [0153]), the contents described in these publications are incorporated herein.
Further, Al-based catalysts include, for example, [0052] to [0054], [0099] to [0104] of JP2012-122051 ([0045] to [0047], [0091] of WO2012 / 029725. [0096]), the contents of which are described in these publications are incorporated herein.
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 Al element with respect to the mass of the polyester resin.

(1-3-2) Sb-based catalyst:
As the Sb-based catalyst, Sb-based catalysts described in JP-A-2012-41519, [0050] and [0052] to [0054] can be used.
Although there is no restriction | limiting in particular as a method of superposing | polymerizing a polyester resin using a Sb type | system | group catalyst, Specifically, it can superpose | polymerize according to [0086]-[0087] of WO2012 / 157762.

(1-4) Additive:
It is also preferable to add a known additive to the polyester film according to this embodiment. Examples thereof include ultraviolet absorbers, particles, lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light resistance agents, impact resistance improvers, lubricants, dyes, pigments and the like. However, since the polyester film generally requires transparency, it is preferable to keep the additive amount to a minimum.

(1-4-1) Ultraviolet (UV) absorber:
The polyester film according to this embodiment may contain an ultraviolet absorber in order to prevent the liquid crystal or the like of the liquid crystal display from being deteriorated by 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 that can withstand the heat applied in the production process of the polyester film.
Examples of the ultraviolet absorber include an organic ultraviolet absorber and an inorganic ultraviolet absorber, and an organic ultraviolet absorber is preferable from the viewpoint of transparency. An ultraviolet absorber described in [0057] of WO2012 / 157762 or a cyclic iminoester-based ultraviolet absorber described later can be used.

  Examples of the cyclic iminoester-based ultraviolet absorber include, but are not limited to, 2-methyl-3,1-benzoxazin-4-one, 2-butyl-3,1-benzoxazin-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-benzoxazin-4-one, 2-m-nitrophenyl-3,1-benzoxazin-4-one, 2-p-benzoylphenyl-3, 1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1-benzoxazin-4-one, 2-o-methoxyphenyl-3,1-benzoxazin-4-one, 2-cyclohex Sil-3,1-benzoxazin-4-one, 2-p- (or m-) phthalimidophenyl-3,1-benzoxazin-4-one, N-phenyl-4- (3,1-benzoxazine- 4-On-2-yl) phthalimide, N-benzoyl-4- (3,1-benzoxazin-4-one-2-yl) aniline, N-benzoyl-N-methyl-4- (3,1-benzo Oxazin-4-one-2-yl) aniline, 2- (p- (N-methylcarbonyl) phenyl) -3,1-benzoxazin-4-one, 2,2′-bis (3,1-benzoxazine -4-one), 2,2′-ethylenebis (3,1-benzoxazin-4-one), 2,2′-tetramethylenebis (3,1-benzoxazin-4-one), 2,2 '-Decamethylenebis (3 1-benzoxazin-4-one, 2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazin-4-one) [Note that 2,2′-p-phenylenebis (3 , 1-benzoxazin-4-one)], 2,2′-m-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2,6- or 1,5-naphthylene) bis (3,1-benzoxazin-4-one), 2,2 ′-( 2-methyl-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2-nitro-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2-Chloro-p-phenylene) bis (3,1-benzooxy) Sadin-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-benzoxazin-4-on-2-yl) naphthalene, 2,4,6-tri (3,1-benzoxazine-4) -On-2-yl) naphthalene, 2,8-dimethyl-4H, 6H-benzo (1,2-d; 5,4-d ') bis (1,3) -oxazine-4,6-dione, , 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-diph Nyl-4H, 9H-benzo (1,2-d; 4,5-d ′) bis (1,3) -oxazine-4,6-dione, 6,6′-bis (2-methyl-4H, 3 , 1-Benzoxazin-4-one), 6,6′-bis (2-ethyl-4H, 3,1-benzoxazin-4-one), 6,6′-bis (2-phenyl-4H, 3 , 1-benzoxazin-4-one), 6,6′-methylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-methylenebis (2-phenyl-4H, 3 , 1-benzoxazin-4-one), 6,6′-ethylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-ethylenebis (2-phenyl-4H) , 3,1-benzoxazin-4-one), 6,6′-butylenebis (2 Methyl-4H, 3,1-benzoxazin-4-one), 6,6′-butylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-oxybis (2- Methyl-4H, 3,1-benzoxazin-4-one), 6,6′-oxybis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-sulfonylbis (2 -Methyl-4H, 3,1-benzoxazin-4-one), 6,6'-sulfonylbis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6'-carbonylbis (2-methyl-4H, 3,1-benzoxazin-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-benzoxazin-4-one), 7,7′-ethylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-oxybis (2-methyl-4H) , 3,1-benzoxazin-4-one), 7,7′-sulfonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-carbonylbis (2-methyl) -4H, 3,1-benzoxazin-4-one), 6,7'-bis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,7'-bis (2-phenyl) -4H, 3,1-benzoxazin-4-one, 6,7 ' Methylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,7'- methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), and the like.

  Among the above compounds, when the color tone is taken into consideration, a benzoxazinone-based compound that is difficult to be yellowed is preferably used. For example, a compound represented by the following formula (6) is more preferably used.

Formula (6)

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 group, but are not necessarily limited thereto.

  Functional 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-benzoxazin-4-one) is particularly preferable.

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

Moreover, when the polyester film which concerns on this embodiment has a laminated structure, it is preferable that it is at least 3 layer structure, and it is preferable that the ultraviolet absorber is mix | blended with the intermediate | middle layer (layers other than outermost layer). By blending the UV absorber in the intermediate layer, the UV absorber can be prevented from bleeding out to the film surface, and as a result, the properties such as the adhesiveness of the film can be maintained.
For example, the master batch method described in [0050] to [0051] of WO2011 / 162198 can be used for blending the ultraviolet absorber.

(1-4-2) Other Additives Other additives may be used for the polyester film according to the present embodiment. For example, the additive described in [0058] of WO2012 / 157762 can be used. Is incorporated herein by reference.

[Production method of polyester film]
Using a lateral stretching device provided with a plurality of clips respectively traveling along a pair of rails installed on both sides of the film conveyance path,
A preheating step of preheating an unstretched or longitudinally stretched polyester film at a heating rate of 600 ° C./min or less;
In the state where both edges of the preheated polyester film are held by a plurality of clips, the film is stretched in the direction perpendicular to the film conveyance path, and the surface temperature of the polyester film (hereinafter, 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 90 ° C. or more and 105 ° C. or less. A transverse stretching step for controlling and controlling the transverse stretching ratio in a range of 3.3 times to 4.8 times;
A heat setting step of heat-setting the polyester film after the transverse drawing step by heating to the maximum temperature in the transverse drawing apparatus,
It is a manufacturing method of the polyester film which manufactures the polyester film whose thickness is 40-500 micrometers.
Here, “unstretched polyester film” means a polyester film in which the refractive indexes of MD and TD are both 1.590 or less. For example, MD and TD may be slightly stretched in MD. A polyester film having a refractive index of 1.590 or less is also included in the substantially unstretched polyester film.
Hereinafter, as a preferable aspect 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 will be described.

<Melting and kneading>
The unstretched polyester film is preferably formed into a film by melt-extruding a polyester resin.
After drying the polyester resin or the master batch of the polyester resin and additive produced by the above-described master batch method to a moisture content of 200 ppm or less, it is preferably introduced into a single or twin screw extruder and melted. At this time, in order to suppress decomposition of the polyester resin, it is also preferable to melt in a nitrogen or vacuum. The detailed conditions can be carried out according to these publications, for example, with the aid of [0051] to [0052] (US 2013/0100378 publication [0085] to [0086]) described in Japanese Patent No. 4926661. The contents of which are incorporated herein by reference. Furthermore, it is also preferable to use a gear pump in order to increase the delivery accuracy of the molten resin (melt). It is also preferable to use a filter having a pore diameter of 3 μm to 20 μm for removing foreign substances.

<Extrusion or coextrusion>
Although it is preferable to extrude the melt containing the polyester resin melt-kneaded from the die, it may be extruded as a single layer or may be extruded as a multilayer (coextrusion). When extruding in multiple layers, for example, a layer containing an ultraviolet absorber (UV agent) and a layer not containing it may be laminated, and more preferably, a three-layer structure in which a layer containing a UV agent is an inner layer is polarized by ultraviolet rays. In addition to suppressing the deterioration of the child, it is preferable to suppress the bleeding out of the UV agent.
The bleed-out UV agent is transferred to a roll in contact with the film in the film production process, which increases the coefficient of friction between the film and the roll and is liable to cause scratches.
When the polyester film is produced by being extruded in multiple layers, the thickness (ratio to the total layer) of a preferable inner layer (a layer other than the outermost layer) of the obtained polyester film is preferably 50% or more and 95% or less, more preferably 60%. It is 90% or less, more preferably 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 [0059] of JP 2009-269301 A, it is preferable to extrude the melt extruded from the die onto a casting drum and solidify by cooling to obtain an unstretched polyester film (raw fabric).
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 1.580 or less. Further preferred.

In the method for producing a polyester film according to this embodiment, the crystallinity of the unstretched polyester film is preferably 5% or less, more preferably 3% or less, and even more preferably 1% or less. In addition, the crystallinity degree of an unstretched polyester film here means the crystallinity degree of the center part of a film width direction (TD).
When adjusting the degree of crystallinity, the temperature of the end of the casting drum may be lowered, or air may be blown onto the cast drum.
The crystallinity can be calculated from the density of the film. That is, the density X (g / ^cm 3) of the film density at a crystallinity of ^{0% Y = 1.335g / cm 3} , using density Z = 1.501g / cm ³ at 100% crystalline below The crystallinity (%) can be derived from the calculation formula.
Crystallinity = {Z × (XY)} / {X × (ZY)} × 100
The density is measured according to JIS K7112.

<Formation of polymer layer>
The unstretched polyester film that has been melt-extruded may be formed by coating with a polymer layer according to the purpose before or after stretching, which will be described later.
Examples of the polymer layer generally include a functional layer that the polarizing plate may have, and among them, it is preferable to form an easy adhesion layer. The easy-adhesion layer can be applied by the method described in [0062] to [0070] of WO2012 / 157762, for example.

<Preheating>
FIG. 3 schematically shows an example of the configuration of a transverse stretching apparatus used in the transverse stretching step.
As a preheating step until the start of stretching in the transverse stretching step, it is preferable to preheat an unstretched polyester film at a temperature increase rate of 600 ° C./min or less. If the heating rate of the film until the start of stretching in the transverse stretching process is 600 ° C./min or less, the film will be stretched in a state where the molecular chain has sufficiently moved, and the shear plane normal stress and shear plane yield stress will increase excessively. Is suppressed.
From this viewpoint, the temperature increase rate in the preheating step is more preferably 500 ° C./min or less, and further preferably 400 ° C./min or less.
The heating rate 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 transverse stretching step, as shown in FIG. 3, a transverse stretching device (also referred to as “tenter-type stretching device” or “tenter”) having a plurality of clips 20 that travel along a pair of rails installed on both sides of the film conveyance path. .) Is used for lateral stretching while both edges of the unstretched polyester film are gripped by the clips 20 respectively. In addition, you may hold | grip an unstretched polyester film with a clip from the stage of a preheating process.

  There is no restriction | limiting in particular as a lateral stretch apparatus which has the clip 20 which drive | works along a pair of rail installed in the both sides of a film conveyance path. A pair of endless rails is usually used as the pair of rails. In addition, a clip is synonymous with a holding member.

  An unstretched polyester film is stretched transversely. The lateral stretching is performed in a direction (TD) orthogonal to the film transport direction (MD) while transporting an unstretched polyester film along the film transport path. That is, the lateral stretching can be achieved by holding both ends of the film with clips and widening between the clips while heating.

  By stretching in the transverse direction, the retardation Re in the in-plane direction can be greatly 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. Note that longitudinal stretching may be performed before the preheating step or before the transverse stretching step.

The surface temperature at the start of stretching in the transverse stretching step is preferably from 80 ° C to 95 ° C, more preferably from 82 ° C to 93 ° C, and still more preferably from 84 ° C to 92 ° C.
If the surface temperature at the start of stretching in the transverse stretching step is 80 ° C. or higher, the orientation and orientation crystallization do not proceed excessively in the stretching stage, and the shear plane normal stress and shear plane yield stress are prevented from excessively increasing. Further, the rise in Rth is suppressed, and the Re / Rth ratio is 0.6 or more, so that the visibility of rainbow unevenness is suppressed.
If the surface temperature at the start of stretching in the transverse stretching process is 95 ° C or less, the growth of spherulites due to insufficient orientation is suppressed, the shear plane normal stress and the shear plane yield stress are reduced too much, and the film is prevented from becoming cloudy. In addition, Re is likely to rise sufficiently.

In the method for producing a polyester film according to this embodiment, the surface temperature at the end of stretching in the transverse stretching step is preferably 90 ° C. or higher and 105 ° C. or lower, more preferably 92 ° C. or higher and 102 ° C. or lower, and 93 ° C. or higher and 100 ° C. or lower. Further preferred.
If the surface temperature at the end of stretching in the transverse stretching step is 90 ° C. or higher, the orientation and orientation crystallization do not proceed excessively in the stretching step, and the shear plane normal stress and shear plane yield stress are prevented from excessively increasing. Further, the rise in Rth is suppressed, and the Re / Rth ratio is 0.6 or more, so that the visibility of rainbow unevenness is suppressed.
If the surface temperature at the end of stretching in the transverse stretching process is 105 ° C. or less, the growth of spherulites due to insufficient orientation is suppressed, the shear plane normal stress and the shear plane yield stress are excessively decreased, and the film is prevented from becoming clouded. Therefore, Re that affects the suppression of rainbow unevenness is likely to rise sufficiently.

The surface temperature is gradually raised from the start of stretching in the transverse stretching step to the end of stretching. Here, “gradually rising” may be a continuous increase or a stepwise increase.
The difference in surface temperature between the end of stretching and the start of stretching is preferably 1 ° C. or higher, more preferably 3 ° C. or higher, and most preferably 5 ° C. or higher.
When the surface temperature is gradually increased from the start of stretching to the end of stretching, spherulites are less likely to be formed and the orientation is prevented from proceeding excessively. It becomes difficult to see.

The transverse draw ratio in the transverse drawing step is preferably controlled in the range of 3.3 times to 4.8 times, more preferably 3.5 times to 4.5 times, and more preferably 3.7 times to 4.3 times. Even less than double is more preferable.
When the transverse draw ratio is 3.3 times or more, the shear plane normal stress and the shear plane yield stress of the film are suppressed from being excessively decreased, and the reduction in Re effective in suppressing 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 are prevented from excessively increasing and becoming brittle.

In the transverse stretching step, the surface temperature when the transverse stretching ratio is in the range of 1 to 2 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. or less. Further preferred.
If the surface temperature in the transverse stretching step is in the range of 1 to 2 and the surface temperature is 80 ° C. or more, the orientation and orientation crystallization will not progress excessively in the stretching stage, and shear surface normal stress and shear surface yielding will occur. It is suppressed that the stress rises too much. Further, the rise in Rth is suppressed, and the Re / Rth ratio is 0.6 or more, so that the visibility of rainbow unevenness is suppressed.
If the surface temperature is 92 ° C. or less when the transverse draw ratio in the transverse drawing step is in the range of 1 to 2 times, the growth of spherulites due to insufficient orientation is suppressed, and the shear plane normal stress and shear plane yield stress are reduced. Of the rainbow unevenness is suppressed without being excessively lowered and Re is not sufficiently increased.

In the transverse stretching step, the surface temperature when the transverse stretching ratio is in the range of 2 to 3 is preferably 85 ° C. or higher and 97 ° C. or lower, more preferably 86 ° C. or higher and 97 ° C. or lower, and 87 ° C. or higher and 96 ° C. or lower. Further preferred.
In the transverse stretching step, if the surface temperature when the transverse stretching ratio is in the range of 2 times to less than 3 times is 85 ° C. or more, the orientation and orientation crystallization do not proceed excessively in the stretching stage, and the shear plane normal stress and shear plane An excessive increase in yield stress is suppressed. Further, the rise in Rth is suppressed, and the Re / Rth ratio is 0.6 or less, so that the visibility of rainbow unevenness is suppressed.
In the transverse stretching step, if the surface temperature when the transverse stretching ratio is in the range of 2 times to less than 3 times is 97 ° C. or less, the growth of spherulites due to insufficient orientation is suppressed, the shear plane normal stress and the shear plane yield It is suppressed that the stress is too low. In addition, Re, which is effective in suppressing rainbow unevenness, is sufficiently increased, and rainbow unevenness is suppressed from being visually recognized.

In the transverse stretching step, the surface temperature when the transverse stretching ratio is 3 or more is preferably 90 ° C. or higher and 102 ° C. or lower, more preferably 92 ° C. or higher and 101 ° C. or lower, and still more preferably 93 ° C. or higher and 100 ° C. or lower.
In the transverse stretching step, if the surface temperature when the transverse stretching ratio is in the range of 3 times or more is 90 ° C. or more, the orientation and orientation crystallization do not proceed excessively in the stretching stage, and the shear plane normal stress and shear plane yield stress are It is suppressed that it goes up too much. Further, the rise of Rth is suppressed, and the Re / Rth ratio becomes 0.6 or more, thereby suppressing the rainbow unevenness from being visually recognized.
In the transverse stretching step, if the surface temperature when the transverse stretching ratio is in the range of 3 times or more is 102 ° C. or less, the growth of spherulites due to insufficient orientation is suppressed, and the shear plane normal stress and shear plane yield stress decrease. Too much is suppressed. In addition, Re increases sufficiently, and the visibility of rainbow unevenness is suppressed.

  In addition, in order to gradually increase the surface temperature from the start of stretching to the end of stretching, in the transverse stretching step, the surface temperature when the transverse stretching ratio is in the range of 1 to 2 but the transverse stretching ratio is 2 or more. The surface temperature in the range of less than 3 times and the surface temperature in the range of the transverse draw ratio of 3 times or more do not fall below the surface temperature in the stretch range 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 become lower than the surface temperature when the transverse draw ratio is in the range of 1 time or more and less than 2 times. The surface temperature when it is in the range of 3 times or more does not fall below 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 temperature increase rate of the surface temperature during stretching is preferably 60 ° C./min or less, more preferably 50 ° C./min or less, and even more preferably 40 ° C./min or less.
In the transverse stretching step, when the temperature rising rate of the surface temperature during stretching is 60 ° C./min or less, the molecular chain is prevented from moving rapidly during stretching, and the shear plane normal stress and shear plane yield stress are too low. It is suppressed. In addition, Re, which is effective in suppressing rainbow unevenness, is sufficiently increased, making it difficult to visually recognize rainbow unevenness.
In the transverse stretching step, the temperature increase rate of the surface temperature during stretching is 5 ° C./min to 60 ° C./min, 5 ° C./min to 50 ° C./min, or 5 ° C./min to 40 ° C./min. There may be.

<Heat setting>
It includes a heat setting step in which the polyester film after transverse stretching is heat-set by heating to the maximum temperature in the transverse stretching apparatus.
After stretching, a heat treatment called “heat setting” is performed 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, volume shrinks due to crystallization.
As a method of heat setting, several slits for sending hot air to the extending portion are provided in parallel to the width direction, and the temperature of the gas blown out from the slit can be increased by higher than that of the extending portion.
Further, a heat source (IR heater, halogen heater, etc.) may be installed near the exit of the stretching (part) to raise the temperature.

The maximum surface temperature of the polyester film in the heat setting step is preferably 130 ° C to 230 ° C, more preferably 150 ° C to 210 ° C, and still more preferably 160 ° C to 200 ° C.
If the maximum surface temperature in the heat setting process is 130 ° C or higher, the shear surface normal stress and shear surface yield stress are prevented from excessively decreasing, and if it is 230 ° C or lower, the shear surface normal stress and shear surface yield stress increase. Too much is suppressed.

The heating rate of the surface temperature of the film from the end of the transverse stretching process until reaching the maximum temperature in the heat setting process is preferably 1000 ° C./min or less, more preferably 800 ° C./min or less, and still more preferably 700 ° C./min or less. .
Here, the “maximum temperature in the heat setting process” refers to the highest surface temperature reached by the film in the heat setting zone, and the surface temperature (film surface temperature) of the film in the heat setting zone is a radiation thermometer. It can be obtained by actually measuring with.

If the heating rate of the film in the heat setting process from the end of the transverse stretching process is 1000 ° C./min or less, the rapid relaxation of molecules before crystallization is suppressed, and the shear plane normal stress and shear plane yield stress are It is suppressed that the rainbow unevenness is visually recognized because the Re is not excessively lowered or the Re is not sufficiently increased.
The temperature increase rate of the surface temperature of the film from the end of the transverse stretching process to the maximum temperature in the heat setting process is 50 ° C./min or more and 1000 ° C./min or less, 50 ° C./min or more and 800 ° C./min or less, or 50 It may be at least 700 ° C./min.

The time when the surface temperature exceeds 130 ° C. is preferably 180 seconds or shorter, more preferably 120 seconds or shorter, and even more preferably 60 seconds or shorter.
If the surface temperature exceeds 130 ° C for 180 seconds or less, crystallization does not proceed excessively, the shear plane normal stress and shear plane yield stress increase excessively, or Rth increases excessively and rainbow unevenness is visually recognized. Is suppressed.
The time during which the surface temperature exceeds 130 ° C. may be 10 seconds to 180 seconds, 10 seconds to 120 seconds, or 10 seconds to 60 seconds.

<Heat relaxation>
It is preferable to include a thermal relaxation step of heating the polyester film after the heat setting step and reducing the length of at least the transverse direction (TD) of the polyester film. In other words, before releasing the polyester film after transverse stretching from the clip, while heating the polyester film after transverse stretching, the polyester film after transverse stretching is heated to the maximum temperature in the transverse stretching apparatus, It is preferable to include a thermal relaxation step of narrowing the distance between the pair of rails.
The heat relaxation step is not strictly limited to an embodiment performed after the heat setting step, and the heat setting step and the heat relaxation step may be performed simultaneously. When performing the heat setting process and the heat relaxation process at the same time, the heat setting process is performed until the maximum temperature in the transverse stretching apparatus is reached, and the heat relaxation is continued at a temperature not exceeding the maximum temperature in the transverse stretching apparatus. Is preferred.
It is preferable to perform relaxation (shrink the film) simultaneously with the heat treatment after the heat setting step, and it is preferable to perform at least one of TD (transverse direction) and MD (vertical direction).
Lateral relaxation can be achieved by reducing the width of the widened clip.
Such relaxation may be achieved, for example, by using a pantograph-like chuck for the tenter, reducing the interval between the pantographs, and driving the clip on the electromagnet to reduce the speed.
In the heat relaxation step, it is preferable that the MD relaxation rate, which is a ratio of reducing the MD length of the heat-fixed polyester film, be 1 to 7% from the viewpoint of suppressing generation of scratches on the polyester film, and 2 to 6 % Is more preferable, and 3 to 5% is still more preferable. When the relaxation rate of MD is 1% or more, the thermal shrinkage rate of MD can be reduced and wrinkles are less likely to occur. It is preferable that the MD relaxation rate is 7% or less because it is difficult for the MD to loosen during the relaxation treatment, and it is difficult to cause a planar failure.
From the viewpoint of suppressing the occurrence of scratches on the polyester film, it is preferable that the relaxation rate of TD, which is a ratio of reducing the length of TD of the heat-fixed polyester film, is more preferably 1 to 4%. 1 to 3% is more preferable. It is preferable that the relaxation rate of TD is 6% or less because it is difficult for TD to loosen during the relaxation treatment, and it is difficult to cause a planar failure.

  The relaxation temperature of TD (transverse direction) is preferably in the above-mentioned range of the heat setting temperature, and the same temperature as the heat setting as long as the heat setting for heating the polyester film after the horizontal stretching to the maximum temperature in the horizontal stretching apparatus can be performed. However, it may be low (that is, even if the maximum temperature in the transverse stretching apparatus is reached).

  By performing the preheating step, the transverse stretching step, the heat setting step, and the thermal relaxation step performed as necessary, Re, Rth, and Re / Rth of the polyester film according to the present embodiment can be easily achieved. It is easy to manufacture the polyester film according to the present embodiment that exhibits the effect of reduction.

<Cooling>
It is preferable to include a step of cooling the polyester film before releasing the polyester film after heat setting or heat relaxation from the clip. The polyester film after heat setting or heat relaxation is preferably cooled before being released from the clip from the viewpoint of easily reducing 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.
Specific examples of the method for cooling the polyester film after heat setting include a method in which cold air is applied to the polyester film.

  In the preheating, stretching, heat setting, thermal relaxation, and cooling in the present embodiment, as the temperature control means for heating or cooling the polyester film, spraying warm or cold air on the polyester film, The surface of the metal plate which can be temperature-controlled is mentioned, or the vicinity of a metal plate is passed.

<Release film from clip>
After 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. The surface temperature of the polyester film when the polyester film is detached from the clip is more preferably 50 ° C. or more and 120 ° C. or less, and further preferably 60 ° C. or more and 100 ° C. or less.

  In the method for producing a polyester film according to this embodiment, the thickness of the polyester film after completion of film formation (after the step of releasing 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. Further preferred. The reason why it is preferable to set the thickness of the polyester film in the above range is the same as the reason for the thickness of the polyester film according to this embodiment described above.

<Recovery of film, slit and winding>
After release from the clip, the film is trimmed, slit, and thickened as necessary and wound up for collection.
In the method for producing a polyester film according to this embodiment, the film width after opening from the clip is preferably 0.8 to 6 m from the viewpoint of efficiently securing the film product width and preventing the apparatus size from becoming excessive. More preferably, it is -5m, and it is especially preferable that it is 1-4m. An optical film requiring accuracy is usually formed with a thickness of less than 3 m, but in the present embodiment, it is preferable to form with a width as described above.
In addition, the film formed into a wide film may be slit to preferably 2 or more, 6 or less, more preferably 2 or more and 5 or less, and still more preferably 3 or more and 4 or less, and then wound.

After slitting, it is preferable to process the thickness at both ends (knurling).
The winding is preferably performed at a diameter of not less than 1000 m and not more than 10,000 m on a winding core having a diameter of 70 mm or more and 600 mm or less. Winding tension per cross-sectional area of the film is preferably 3~30kgf / cm ^2, more preferably 5~25kgf / cm ^2, more preferably from 7~20kgf / cm ^2. It is also preferable to bond a masking film before winding.

[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 includes a base film including the polyester film according to the present embodiment described above and a hard coat layer laminated on at least one surface 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 formation), but is preferably formed by a wet coating method having excellent productivity.
As the hard coat layer, for example, JP 2013-45045 A, JP 2013-43352 A, JP 2012-232459 A, JP 2012-128157 A, JP 2011-131409 A, JP JP2011-131404A, JP2011-126162A, JP2011-75705A, JP2009-286981, JP2009-263567, JP2009-75248, JP2007-. No. 164206, JP-A No. 2006-96811, JP-A No. 2004-75970, JP-A No. 2002-156505, JP-A No. 2001-272503, WO12 / 018087, WO12 / 098967, WO12 / 0886659, WO11 / Described in 105594 The Dokoto layer can be used.

(Thickness of hard coat layer)
The thickness of the hard coat layer of the hard coat film according to this embodiment is preferably 5 μm or more. If the thickness of the hard coat layer is 5 μm or more, a hard coat film having high scratch resistance can be obtained.
From this viewpoint, the thickness of the hard coat layer of the hard coat film according to this embodiment is more preferably 10 μm or more, and further preferably 15 μm or more.
In addition, since the punching process tends to be difficult when the thickness of the hard coat layer is too thick, the thickness of the hard coat layer is preferably 40 μm or less, and more preferably 35 μm or less.

(Constituent material of hard coat layer)
The hard coat layer of the hard coat film according to this embodiment is
At least a structure derived from a) below, a structure derived from b) below, c) and d) below,
When the hard coat layer has a total solid content of the hard coat layer of 100% by mass, the structure derived from the following a) is 15 to 70% by mass, the structure derived from the following b) is 25 to 80% by mass, and the following c) It is preferable that 0.1-10 mass% and 0.1-10 mass% of following d) are included.
a) a compound having one alicyclic epoxy group and one group containing an ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less; b) three or more ethylenic groups in the molecule. Compound having a group containing a saturated double bond c) Radical polymerization initiator d) Cationic polymerization initiator By providing the hard coat layer having such a configuration, the hard coat film according to this embodiment has high pencil hardness, Excellent in smoothness, and changes in film appearance after wet heat aging are suppressed.

In the present embodiment, the hard coat layer preferably has a hard coat property. In this specification, the hard coat property means a pencil hardness of 7H or more from the viewpoint of being used as an outermost surface protective film of an image display device as a glass substitute hard coat film. The hard coat layer preferably has a pencil hardness of 8H or higher.
The hard coat film according to this embodiment having such a configuration is preferably manufactured by a method for manufacturing a hard coat film according to this embodiment described later.

<Configuration>
It is preferable that the hard coat film which concerns on this embodiment is the structure which coated the hard-coat layer on the at least one surface of the polyester film which concerns on this embodiment mentioned 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 a hard coat layer. When the total solid content of the forming composition is 100% by mass, a) is 15-70% by mass, b) is 25-80% by mass, c) is 0.1-10% by mass, d) is 0.1% by mass. It is more preferable to contain 1-10 mass%.

<Hardcoat layer and hardcoat layer forming composition>
Hereinafter, the detail about each component contained in the composition for hard-coat layer and hard-coat layer formation is described.

[A) Compound having 1 alicyclic epoxy group and 1 ethylenically unsaturated double bond in the molecule, and a molecular weight of 300 or less]
The hard coat film which concerns on this embodiment contains 15-70 mass% of structures derived from the following a), when a hard-coat layer makes the total solid of a hard-coat layer 100 mass%.
a) A compound having one alicyclic epoxy group and one ethylenically unsaturated double bond group in the molecule and having a molecular weight of 300 or less.
The hard coat layer is formed by curing a composition for forming a hard coat layer containing at least a), b), c) and d), and the composition for forming a hard coat layer is a composition for forming a hard coat layer. When the total solid content of the product is 100% by mass, a) is preferably contained in an amount of 15 to 70% by mass.

  A) Contained in the composition for forming a hard coat layer a) a compound having one alicyclic epoxy group and one group containing an ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less explain. a) A compound having one alicyclic epoxy group and one group containing an 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 a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group and —C (O) OCH═CH ₂ is preferable, and a (meth) acryloyl group is particularly preferable. By having a group containing an ethylenically unsaturated double bond, high hardness can be maintained and heat and heat resistance can also be imparted.

  In this specification, “(meth) acryloyl group” includes “acryloyl group” and “methacryloyl group”, and “(meth) acrylate” includes “acrylate” and “methacrylate”. “(Meth) acryl” means “acryl” and “methacryl”.

  In the present embodiment, the number of groups containing an epoxy group and an ethylenically unsaturated double bond in the molecule is one. When each functional group is 1, the number of functional groups (groups containing an epoxy group and an ethylenically unsaturated double bond) is reduced as compared to the case of 2 or more, thereby reducing the molecular weight and pencil hardness. This is because of the increase.

The molecular weight of the component a) is 300 or less, preferably 210 or less, and more preferably 200 or less.
By setting the molecular weight of the component a) to 300 or less, sites other than the group containing an epoxy group and an ethylenically unsaturated double bond are reduced, and the pencil hardness can be increased.
Further, from the viewpoint of suppressing volatilization during the 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 component a) is not limited as long as it has one alicyclic epoxy group and one ethylenically unsaturated double bond group in the molecule and has a molecular weight of 300 or less. It is preferable that it is a compound represented by 7).

Formula (7)

  In formula (7), R represents a monocyclic hydrocarbon or a bridged 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, more preferably an alicyclic group having 4 to 10 carbon atoms, and an alicyclic group having 5 to 7 carbon atoms. Group is more preferable, and an alicyclic group having 6 carbon atoms is particularly preferable. 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 the formula (7) is a bridged hydrocarbon, a two-ring bridge (bicyclo ring) or a three-ring bridge (tricyclo ring) is preferable, and examples thereof include a bridged hydrocarbon having 5 to 20 carbon atoms, and a norbornyl group Bornyl group, isobornyl group, tricyclodecyl group, dicyclopentenyl group, dicyclopentanyl group, tricyclopentenyl group, 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 preferred. As a bivalent aliphatic hydrocarbon group, 1-6 are preferable, as for carbon number, 1-3 are more preferable, and 1 is still 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 still more preferable.
Examples of Q include polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group and —C (O) OCH═CH ₂ are preferable and particularly preferable. Is a (meth) acryloyl group.

As a specific compound of component a), a compound having one alicyclic epoxy group and one group containing an ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less Although not specifically limited, the compound described in paragraph [0015] of JP-A-10-17614, a compound represented by the following formula (1A) or (1B), 1,2-epoxy-4-vinylcyclohexane, or the like is used. Can do.
Among these, a compound represented by the following formula (1A) or (1B) is more preferable, and a compound represented by the following formula (1A) having a low molecular weight is more preferable. In addition, the compound represented by the following formula (1A) is also preferably an isomer thereof. In the formula of 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 the component having 1 carbon atom (that is, a) is epoxycyclohexylmethyl. (Meth) acrylate) is more preferable from the viewpoint of improving smoothness.
By using these compounds, both high pencil hardness and excellent smoothness can be achieved at a higher level.

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.

In Formula (1B), R ₁ represents a hydrogen atom or a methyl group, and L ₂ represents a C 1-6 divalent aliphatic hydrocarbon group.

The divalent aliphatic hydrocarbon group represented by L _{2 in} the formulas (1A) and (1B) has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and still more preferably 1 carbon atom. 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 still more preferable.

The structure derived from a) is contained in an amount of 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 an amount of 15 to 70% by mass when the total solid content of the hard coat layer forming composition in the present embodiment is 100% by mass. When the content of the structure derived from a) or the component a) relative to the hard coat layer or the hard coat layer forming composition is 15% by mass or more, the surface smoothness is sufficiently improved. On the other hand, when the content of the structure derived from a) or the component a) relative to the hard coat layer or the hard coat layer forming composition is 70% by mass or less, the surface hardness can be sufficiently increased.
When the total solid content of the hard coat layer is 100% by mass, the structure derived from a) is preferably contained in an amount of 18 to 50% by mass, and more preferably 22 to 40% by mass. The component a) is preferably contained in an amount of 18 to 50% by mass when the total solid content of the composition for forming a hard coat layer in the present embodiment is 100% by mass, and contained in an amount of 22 to 40% by mass. Is more preferable.

[B) Compound having a group containing 3 or more ethylenically unsaturated double bonds in the molecule]
The hard coat film which concerns on this embodiment contains 25-80 mass% of structures derived from the following b), when a hard-coat layer makes the total solid of a hard-coat layer 100 mass%.
b) A compound having a group containing 3 or more ethylenically unsaturated double bonds in the molecule.
The hard coat layer is formed by curing a composition for forming a hard coat layer containing at least a), b), c) and d), and the composition for forming a hard coat layer is a composition for forming a hard coat layer. When the total solid content of the product is 100% by mass, it is preferable to contain 25 to 80% by mass of b).
A compound having a group containing 3 or more ethylenically unsaturated double bonds in the molecule b) contained in the composition for forming a hard coat layer in this embodiment will be described. b) A compound having a group containing three or more ethylenically unsaturated double bonds in the molecule is also referred to as “component b”.
The component b) can exhibit high hardness by having a group containing 3 or more ethylenically unsaturated double bonds in the molecule.
The component b) may have a group containing 3 or more and 20 or less ethylenically unsaturated double bonds in the molecule.
Examples of the component b) include esters of polyhydric alcohol and (meth) acrylic acid, vinylbenzene and its derivatives, vinyl sulfone, (meth) acrylamide and the like. Among them, from the viewpoint of hardness, a compound having three or more (meth) acryloyl groups is preferable, and examples thereof include acrylate compounds that form a hardened cured product widely used in the industry. An example of such a compound is an ester of polyhydric alcohol and (meth) acrylic acid having a group containing 3 or more ethylenically unsaturated double bonds in the molecule. For example, (di) pentaerythritol tetra (meth) acrylate, (di) pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (Meth) acrylate, EO-modified tri (meth) acrylate phosphate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, (di) pentaerythritol penta (meth) ) Acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, poly Letane polyacrylate, polyester polyacrylate, caprolactone-modified tris (acryloxyethyl) isocyanurate, tripentaerythritol triacrylate, tripentaerythritol hexatriacrylate, 1,2,4-cyclohexanetetra (meth) acrylate, pentaglycerol triacrylate, Etc.
Furthermore, resin (oligomer or prepolymer) having 3 or more (meth) acryloyl groups, polyfunctional (meth) acrylate having 3 or more (meth) acryloyl groups, and urethane (meth) acrylate are also preferable.
Examples of the resin (oligomer or prepolymer) having three or more (meth) acryloyl groups include polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin, and polythiol. Examples include oligomers or prepolymers such as polyene resins and polyfunctional compounds such as polyhydric alcohols.
Specific examples of the polyfunctional (meth) acrylate having 3 or more (meth) acryloyl groups include exemplified compounds shown in paragraph 0096 of JP-A-2007-256844.
Specific compounds of the polyfunctional acrylate compounds having three or more (meth) acryloyl groups include KAYARAD DPHA, DPHA-2C, PET-30, TMPTA, TPA-320, and TPA-330 manufactured by Nippon Kayaku Co., Ltd. , RP-1040, T-1420, D-310, DPCA-20, DPCA-30, DPCA-60, GPO-303, Osaka Organic Chemical Co., Ltd. V # 400, V # 36095D and other polyols (meta ) An esterified product of acrylic acid can be mentioned. Moreover, purple light 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 Synthetic Chemical Co., Ltd.), UL-503LN (manufactured by Kyoeisha Chemical Co., Ltd.), Unidic 17-806, 17-813, V-4030, V -4000BA (DI EB-1290K, EB-220, EB-5129, EB-1830, EB-4358 (manufactured by Daicel UCB), Hicorp AU-2010, AU-2020 (manufactured by Tokushi Corporation), Aronix M-1960 (manufactured by Toa Gosei Co., Ltd.), Art Resin UN-3320HA, UN-3320HC, UN-3320HS, UN-904, HDP-4T and other trifunctional urethane acrylate compounds, Aronix M-8100, M Trifunctional or higher functional polyester compounds such as -8030, M-9050 (manufactured by Toagosei Co., Ltd.) and KBM-8307 (manufactured by Daicel Cytec Co., Ltd.) can also be suitably used.
Further, the component b) may be composed of a single compound or a combination of a plurality of compounds.

The structure derived from b) is contained in an amount of 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 an amount of 25 to 80% by mass when the total solid content of the hard coat layer forming composition in the present embodiment is 100% by mass. When the content of the structure derived from b) or the content of the component b) is 25% by mass or more with respect to the hard coat layer or the hard coat layer forming composition, sufficient hardness can be obtained. On the other hand, when the content of the b) derived structure or b) component is 80% by mass or less with respect to the hard coat layer or the hard coat layer forming composition, the a derived structure or the content of the a) component is Since it decreases, the smoothness is sufficient.
The structure derived from b) is preferably contained in an amount of 40 to 75% by mass, more preferably 60 to 75% by mass, when the total solid content of the hard coat layer is 100% by mass. When the total solid content of the composition for forming a hard coat layer in this embodiment is 100% by mass, the component b) is preferably contained in an amount of 40 to 75% by mass, and 60 to 75% by mass. Is more preferable.

[Other curable compounds]
The composition for forming a hard coat layer may contain a curable compound other than the component a) and the component b) (hereinafter also referred to as “other curable compound”). As other curable compounds, various compounds having a polymerizable group that can be cured (polymerized) by a curing treatment can be used. Examples of the polymerizable group include a polymerizable group capable of undergoing a polymerization reaction upon irradiation with light, an electron beam or radiation, and a polymerizable group capable of undergoing a polymerization reaction upon heating, and a photopolymerizable group is preferred. Other curable compounds can be monomers, oligomers, prepolymers, and the like.

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

Specific examples of other curable compounds that may be included in the hard coat layer forming composition include the following compounds.
(Meth) acrylic diesters of alkylene glycols such as neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate; triethylene glycol di (meth) acrylate, dipropylene glycol di ( (Meth) acrylate diesters of polyoxyalkylene glycols such as (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate; (meth) of polyhydric alcohols such as pentaerythritol di (meth) acrylate Acrylic acid diesters; 2,2-bis {4- (acryloxy-diethoxy) phenyl} propane, 2,2-bis {4- (acryloxy-polypropoxy) phenyl} propane, etc. Of Chiren'okishido or propylene oxide adduct (meth) acrylic acid diesters; urethane (meth) acrylates, polyesters (meth) acrylates; isocyanuric acid acrylates, epoxy (meth) acrylates.

  As the urethane (meth) acrylate, for example, an alcohol, a polyol, and / or a hydroxyl group-containing compound such as a hydroxyl group-containing acrylate is reacted with an isocyanate, or, if necessary, a polyurethane compound obtained by these reactions ( Mention may be made of urethane (meth) acrylates obtained by esterification with (meth) acrylic acid. Specific examples include various commercially available products listed in paragraph 0017 of JP-A-2007-256844.

  The composition for forming a hard coat layer can also contain an epoxy compound having an epoxy group as a polymerizable group as another curable compound from the viewpoint of reducing curing shrinkage. The epoxy compound is preferably a polyfunctional epoxy compound containing two or more epoxy groups in one molecule. Specific examples include JP-A-2004-264563, JP-A-2004-264564, JP-A-2005-37737, JP-A-2005-37738, JP-A-2005-140862, JP-A-2005-140862. And epoxy compounds described in JP-A No. 2005-140863 and JP-A No. 2002-322430. It is also preferable to use a compound having both an epoxy group and an acrylic polymerizable group such as glycidyl (meth) acrylate.

  From the viewpoint of the hardness of the hard coat layer, the content of the other curable compound with respect to the total solid content of the hard coat layer forming composition is determined when the total solid content of the hard coat layer forming composition is 100% by mass. 15% by mass or less, preferably 10% by mass or less, more preferably 1% by mass or less, still more preferably 0.01% by mass or less, substantially including It is particularly preferred not to.

[C) Radical polymerization initiator]
The hard coat film which concerns on this embodiment contains 0.1-10 mass% of c) radical polymerization initiators, when a hard-coat layer makes the total solid of a hard-coat layer 100 mass%.
The c) radical polymerization initiator contained in the hard coat layer or the hard coat layer forming composition in this embodiment will be described. Hereinafter, the c) radical polymerization initiator is also referred to as “c) component”.
Polymerization of the compound having an ethylenically unsaturated group can be performed by irradiation with 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 described in “Latest UV Curing Technology” (p. 159, publisher: Kazuhiro Takahisa, publisher; Technical Information Association, 1991). Issued) or in the catalog of Ciba Specialty Chemicals Co., Ltd.
Specifically, as the component c), an alkylphenone photopolymerization initiator (Irgacure 651, Irgacure 184, DAROCURE 1173, Irgacure 2959, Irgacure 127, DAROCURE MBF, Irgacure 907, Irgacure 369, Irgacure 369, Irgacure 369, Irgacure 369, Irgacure 369, Irgacure 369 Photopolymerization initiator , LUCIRIN TPO) and others (Irgacure 784, Irgacure OXE01, Irgacure OXE02, Irgacure 754) and the like can be used.

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

[D) Cationic polymerization initiator]
The hard coat film which concerns on this embodiment contains 0.1-10 mass% of d) cationic polymerization initiator, when a hard-coat layer makes the total solid of a hard-coat layer 100 mass%.
The d) cationic polymerization initiator contained in the hard coat layer or the hard coat layer forming composition in this embodiment will be described. Hereinafter, d) cationic polymerization initiator is also referred to as “d) component”.
As component d), known compounds such as photoinitiators for photocationic polymerization, photodecolorants for dyes, photochromic agents, known acid generators used in microresists, and the like, and mixtures thereof Etc.
Examples thereof include onium compounds, organic halogen compounds, and disulfone compounds. Specific examples of these organic halogen compounds and disulfone compounds include the same compounds as those described above for the compounds that generate radicals.

  Examples of the onium compounds include diazonium salts, ammonium salts, iminium salts, phosphonium salts, iodonium salts, sulfonium salts, arsonium salts, selenonium salts, and the like, for example, paragraph numbers [0058] to [0059] of JP-A-2002-29162. And the like.

  In the present embodiment, particularly preferred cationic polymerization initiators include onium salts, and diazonium salts, iodonium salts, sulfonium salts, and iminium salts are used for photopolymerization initiation photosensitivity, compound material stability, and the like. Of these, iodonium salts are most preferable from the viewpoint of light resistance.

  In the present embodiment, specific examples of onium salts that can be suitably used include, for example, an amylated sulfonium salt described in paragraph [0035] of JP-A-9-268205, and JP-A-2000-71366. Diaryl iodonium salts or triaryl sulfonium salts described in paragraph numbers [0010] to [0011] of the publication, and sulfonium salts of thiobenzoic acid S-phenyl esters described in paragraph number [0017] of JP 2001-288205 A; Examples include onium salts described in paragraph numbers [0030] to [0033] of JP-A-2001-133696.

  Other examples include organometallic / organic halides described in JP-A-2002-29162, paragraphs [0059] to [0062], photoacid generators having o-nitrobenzyl type protecting groups, photolysis And compounds that generate sulfonic acid (iminosulfonate, etc.).

  Specific compounds of the iodonium salt-based cationic polymerization initiator include B2380 (manufactured by Tokyo Chemical Industry), BBI-102 (manufactured by Midori Chemical), WPI-113 (manufactured by Wako Pure Chemical Industries), and WPI-124 (manufactured by Wako Pure Chemical Industries). Industry-made), WPI-169 (made by Wako Pure Chemical Industries), WPI-170 (made by Wako Pure Chemical Industries), DTBPI-PFBS (made by Toyo Gosei) can be used.

  Furthermore, the following compounds FK-1 and FK-2 can be mentioned as preferable examples of the iodonium salt-based cationic polymerization initiator.

Photocationic polymerization initiator (iodonium chloride) FK-1

Photocationic polymerization initiator (iodonium salt compound) FK-2

As a component d), only 1 type may be used and 2 or more types may be used together.
The component d) is added in the range of 0.1 to 10% by mass, preferably 0.1 to 10% by mass, when the total solid content of the hard coat layer or the hard coat layer forming composition in this embodiment is 100% by mass. It can add in the ratio of 5-3.0 mass%. The addition amount is preferably in the above range from the viewpoint of stability of the coating solution, polymerization reactivity, and the like.

[E) Inorganic particles having reactivity with an epoxy group or a group containing an ethylenically unsaturated double bond]
In the hard coat layer or the hard coat layer forming composition in the present embodiment, it is preferable to add e) inorganic particles having reactivity with an epoxy group or a group containing an ethylenically unsaturated double bond. Hereinafter, e) inorganic particles having reactivity with 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. Furthermore, pencil hardness can be improved by using inorganic particles having reactivity with an epoxy group or a group containing an ethylenically unsaturated double bond.
Examples of inorganic particles include silica particles, titanium dioxide particles, zirconium oxide particles, and aluminum oxide particles. Among them, e) inorganic particles having reactivity with an epoxy group or a group containing an ethylenically unsaturated double bond are preferably silica particles.

In general, since inorganic particles have low affinity with organic components such as polyfunctional vinyl monomers, they may form aggregates or crack the hard coat layer after curing by simply mixing them. Therefore, in the component e), in order to increase the affinity between the inorganic particles and the organic component, it is preferable to treat the surface of the inorganic particles 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 the inorganic particle or adsorbing to the inorganic particle and a functional group having high affinity with the organic component in the same molecule. Examples of the surface modifier having a functional group capable of binding or adsorbing to inorganic particles include metal alkoxide surface modifiers such as silane, aluminum, titanium, and zirconium, or phosphoric acid groups, sulfuric acid groups, sulfonic acid groups, and carboxylic acid groups. A surface modifier having an anionic group is preferred. Further, the functional group having a high affinity with the organic component may be a functional group that is simply combined with the organic component and hydrophilicity / hydrophobicity. However, a functional group that can be chemically bonded to the organic component is preferable, and an ethylenically unsaturated divalent is particularly preferable. A group containing a heavy bond or a ring-opening polymerizable group is preferred.
In the present embodiment, a preferable surface modifier for inorganic particles is a curable resin having a metal alkoxide or an anionic group and a group containing an ethylenically unsaturated double bond or a ring-opening polymerizable group in the same molecule. By chemically combining with the organic component, the crosslink density of the hard coat layer is increased and the pencil hardness can be increased.

Representative examples of these surface modifiers include the following unsaturated double bond-containing coupling agents, phosphoric acid group-containing organic curable resins, sulfuric acid group-containing organic curable resins, and carboxylic acid group-containing organic curable resins. .
_{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 )

  The surface modification of these inorganic particles is preferably performed in a solution. When the inorganic particles are mechanically finely dispersed, the surface modifier is present together, or after the inorganic particles are finely dispersed, the surface modifier is added and stirred, or before the inorganic particles are finely dispersed. The surface may be modified (if necessary, heated, dried and then heated, or pH changed), and then finely dispersed. As the solution for dissolving the surface modifier, an organic solvent having a large polarity is preferable. Specific examples include known solvents such as alcohols, ketones and esters.

e) The amount of the component added is 5 when the total solid content of the hard coat layer or the hard coat layer forming composition in this embodiment is 100% by mass in consideration of the balance between hardness and brittleness of the coating film. -40 mass% is preferable and 10-30 mass% is more preferable.
The size (average primary particle size) 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 determined from an electron micrograph. If the particle size of the inorganic particles is equal to or greater than the lower limit value, an effect of improving the hardness is obtained, and if the particle size is equal to or smaller than the upper limit value, an increase in haze can be suppressed.
The shape of the inorganic particles may be spherical or non-spherical, but a non-spherical shape in which 2 to 10 inorganic particles are connected is preferable from the viewpoint of imparting hardness. It is presumed that by using inorganic particles in which several particles are linked in a chain, a firm particle network structure is formed and the hardness is improved.
Specific examples of the inorganic particles include ELECOM V-8802 (spherical silica particles having an average primary particle size of 12 nm manufactured by JGC Corporation), ELECOM V-8803 (modified silica particles manufactured by JGC Corporation), MiBK- SD (spherical silica particles having an average primary particle size of 10 to 20 nm manufactured by Nissan Chemical Industries, Ltd.), MEK-AC-2140Z (spherical silica particles having an average primary particle size of 10 to 20 nm manufactured by Nissan Chemical Industries, Ltd.), MEK-AC-4130 (spherical silica particles having an average primary particle size of 40 to 50 nm manufactured by Nissan Chemical Industries, Ltd.), MiBK-SD-L (spherical particles having an average primary particle size of 40 to 50 nm manufactured by Nissan Chemical Industries, Ltd.) Silica particles), MEK-AC-5140Z (spherical silica particles having an average primary particle size of 70 to 100 nm manufactured by Nissan Chemical Industries, Ltd.) and the like. Among these, odd-shaped ELECOM V-8803 is preferable from the viewpoint of imparting surface hardness.

[F) Polyester urethane
In the present embodiment, the hard coat layer or the hard coat layer forming composition preferably contains f) polyester urethane from the viewpoint of increasing brittleness. Hereinafter, f) polyester urethane is also referred to as “f) component”.
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 increasing the hardness of the hard coat layer and imparting appropriate flexibility. It is inferred that this contributes to increasing the hardness and improving brittleness of the hard coat layer.
Moreover, if the polyester urethane content is 1 part by mass or more with respect to 100 parts by mass of the solid content of the hard coat layer or the composition for forming a hard coat layer, the above-described effect due to the addition of the polyester urethane can be sufficiently obtained. The hardness of the cured layer can be maintained as long as it is at most parts. Therefore, the polyester urethane content with respect to 100 parts by mass of the solid content of the hard coat layer or the hard coat layer forming composition 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 from the viewpoint of maintaining the hardness of the hard coat layer, it is more preferably 8 parts by mass or less.

  The use of polyester urethane exhibiting the above tensile strength and tensile elongation as the polyester urethane contributes to achieving both 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 further preferably 50 MPa or more. Moreover, it is preferable that a tensile strength is 70 Mpa or less from a viewpoint of the compatibility stability in the composition for hard-coat layer formation. On the other hand, the tensile elongation is preferably 450% or more, and more preferably 600% or more. Further, from the viewpoint of securing pencil hardness, which is one of the indices 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 monomer components containing at least diol, dicarboxylic acid, and diisocyanate. As these three kinds of monomers, polyester urethane having a hydroxyl group (—OH), a carboxyl group (—COOH), and an isocyanate group (—NCO) at both ends of a hydrocarbon group having an unbranched structure is preferable. .
The hydrocarbon group having an unbranched structure is preferably an alkylene group, an alkenylene group, an alkynylene group, an arylene group, or a combination thereof.
The alkylene group, alkenylene group and alkynylene group preferably 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.
The arylene group is preferably a phenylene group or a naphthylene group, more preferably a phenylene group, and still more preferably a p-phenylene group.
As the hydrocarbon group, the alkylene group, the arylene group, or a combination thereof is particularly preferable.

Diols used as polyester urethane monomers include ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, and 1,5- Pentanediol is 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.
Diisocyanates include 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. preferable.

  The number average molecular weight (Mn) of the polyester urethane is preferably 5000 or more from the viewpoint of affinity with inorganic particles, preferably 10,000 or more, and 50,000 or less from the viewpoint of compatibility with the curable compound. It is preferable that

  Moreover, in one aspect | mode, the polyester urethane may have a reactive group. The reactive group is preferably a polymerizable unsaturated group. About a specific example, it is as having described about the functional group which an inorganic particle may have previously.

  As polyester urethane demonstrated above, the polyester urethane synthesize | combined by the well-known method may be used, and a commercial item may be used. Examples of commercially available products include Byron (registered trademark) series (trade name): manufactured by Toyobo Co., Ltd., Byron UR-2300, Byron UR-3200, Byron UR-3210, Byron UR-3260, Byron UR-5537. Byron UR-8300, Byron UR-8700 and the like can be preferably used.

[G) Antifouling agent]
It is preferable that the hard coat layer or the hard coat layer forming composition in the present embodiment contains g) an antifouling agent because adhesion of fingerprints and dirt is reduced, and the attached dirt can be easily wiped off. . Moreover, it is also preferable from the viewpoint of improving the scratch resistance by improving the slip property of the surface. Hereinafter, g) antifouling agent is also referred to as “g) component”.
In the hard coat film according to the present embodiment, g) the antifouling agent contains a fluorine-containing compound, the fluorine-containing compound has a perfluoropolyether group and a polymerizable unsaturated group, and the polymerizable unsaturated group. It is preferable to have plural in one molecule.
The g) antifouling agent that can be used in this embodiment will be described.

[Fluorine-containing compound having a polymerizable unsaturated group]
g) Antifouling agent contains a fluorine-containing compound, this fluorine-containing compound has a perfluoropolyether group and a polymerizable unsaturated group, and a compound having a plurality of polymerizable unsaturated groups in one molecule ( Hereinafter, the case of “fluorinated antifouling agent”) will be described.
The fluorine-containing antifouling agent is preferably a fluorine-based compound having 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 (per) fluoropolyether group, W represents a linking group, and _RA represents a polymerizable unsaturated group. n represents an integer of 1 to 3. m represents an integer of 1 to 3.

The fluorine-containing antifouling agent is considered to have the following effects (1) to (3) by having a polymerizable unsaturated group.
(1) Solubility in an organic solvent and compatibility with a compound having an unsaturated double bond increase, so that the antifouling agent can be uniformly localized on the surface without forming an aggregate. Conceivable. Moreover, generation | occurrence | production of the defect by an aggregate can be prevented.
(2) Even if the fluorine-containing antifouling agent is localized on the surface, it can form a covalent bond by photopolymerization reaction with the fluorine-containing antifouling agents or with a compound having an unsaturated double bond. Can be prevented, and the deterioration of the antifouling property can be prevented.
(3) Loss of antifouling property and deterioration of appearance due to bleedout of the antifouling agent and precipitation can be prevented.

In the 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 irradiation with active energy rays such as ultraviolet rays or an electron beam. Groups, allyl groups, and the like, and (meth) acryloyl groups, (meth) acryloyloxy groups, and groups in which any hydrogen atom in these groups is substituted with a fluorine atom are preferably used.
As a specific example of the polymerizable unsaturated group, a group having the structure shown below is preferable.

In the formula (F), Rf represents a (per) fluoroalkyl group or a (per) fluoropolyether group.
Here, 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 a species. From the viewpoint of antifouling properties, the fluorine content in Rf is preferably high.

The (per) fluoroalkyl group is preferably a group having 1 to 20 carbon atoms, and more preferably a group having 1 to 10 carbon atoms.
The (per) fluoroalkyl group is a straight chain (for example, —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.) even in the branched structure (for example, 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 Or 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).

  The (per) fluoropolyether group refers to a case where the (per) fluoroalkyl group has an ether bond, and may be a monovalent or divalent group. As the fluoropolyether group, for example, —CH₂OCH₂CF₂CF₃, -CH₂CH₂OCH₂C₄F₈H, -CH₂CH₂OCH₂CH₂C₈F₁₇, -CH₂CH₂OCF₂CF₂OCF₂CF₂H, a fluorocycloalkyl group having 4 to 20 carbon atoms having 4 or more fluorine atoms, and the like. Examples of the perfluoropolyether group include-(CF₂O)_p-(CF ₂CF₂O)_q-,-[CF (CF₃CF₂O]_p― [CF₂(CF₃)]-,-(CF₂CF₂CF₂O)_p-,-(CF₂CF₂O)_p-Etc. are mentioned.
  The total of p and q is preferably 1 to 83, more preferably 1 to 43, and most preferably 5 to 23.
  From the viewpoint that the fluorine-containing antifouling agent is excellent in antifouling property-(CF₂O)_p-(CF₂CF₂O)_qIt is particularly preferable to have a perfluoropolyether group represented by-.
  P and q each 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 the above (1) to (3) can be obtained more remarkably, the fluorine-containing antifouling agent has a perfluoropolyether group and contains a polymerizable unsaturated group in one molecule. It is preferable to have a plurality.

In the formula (F), W represents a linking group. Examples of W include an alkylene group, an arylene group, a heteroalkylene group, and a linking group obtained by combining these. These linking groups may further have a functional group such as an oxy group, a carbonyl group, a carbonyloxy group, a carbonylimino group, a sulfonamide group, etc., or a combination thereof.
W is preferably an ethylene group, more preferably an ethylene group bonded to a carbonylimino group.

  From the viewpoint that the effects shown in the above (1) to (3) can be obtained 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. .

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

Formula (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 either 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 Represents an alkylene group, R ′ ² represents a single bond or a divalent linking group, p is an integer indicating the degree of polymerization, and the degree of polymerization p is k (k is an integer of 3 or more) or more.

When R ′ ² represents a divalent linking group, examples of the divalent linking group include the same linking groups as W.

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

  Specific examples of the compound represented by Formula (F-1) are shown below, but are not limited to these compounds.

  When telomerization is used in the synthesis of the compound represented by the above formula (F-1), the group Rf of the formula (F-1) may be used depending on the conditions of telomerization and the separation conditions of the reaction mixture. ²(CF₂CF₂)_pR ’²CH₂CH₂R²O-p may contain a plurality of fluorine-containing (meth) acrylic acid esters such as k, k + 1, k + 2,.

Formula (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 fluorine-containing (meth) acrylic acid ester represented by the formula (F-2) has a fluoroalkyl group having 1 to 20 carbon atoms having a trifluoromethyl group (CF _3- ) at the terminal. Even if a small amount of fluorine (meth) acrylate is used, the trifluoromethyl group is effectively oriented on the surface.

  In view of antifouling properties and ease of production, q is preferably 6 to 20, and more preferably 8 to 10. The fluorine-containing (meth) acrylic acid ester having a fluoroalkyl group having 8 to 10 carbon atoms is superior in water repellency and water repellency compared with other fluorine-containing (meth) acrylic acid esters having a fluoroalkyl group having a chain length. Because it exhibits oiliness, it has excellent antifouling properties.

  Specifically, as the fluorine-containing (meth) acrylic acid ester represented by the formula (F-2), 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-heneicosafluorotridecane, 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-heneicosafluorotridecane 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-heneico Examples include safluorotridecane. 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.

Formula (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 represents a hydrogen atom or a methyl group, s represents 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 formula (F-3) reacts a fluorine atom-containing alcohol compound represented by the following formula (FG-3) and a (meth) acrylic acid halide. Can be obtained.

Formula (FG-3):
_{F (CF 2) r O (} CF 2 CF 2 O) s CF 2 CH 2 OH
In formula (FG-3), s represents an integer of 1 to 20, and r represents an integer of 1 to 4.

Specific examples of the fluorine atom-containing alcohol compound represented by the formula (FG-3) include, for example, 1H, 1H-perfluoro-3,6-dioxaheptan-1-ol, 1H, 1H-perfluoro-3,6. -Dioxaoctane-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-perfluo -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-hept Oxa pen octopus San-1-ol, and the like can be given.
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 Exfloor), 1H, 1H-perfluoro- 3,6,9-trioxadecan-1-ol (trade name “C7GOL”, manufactured by Exfloor), 1H, 1H-perfluoro-3,6-dioxadecan-1-ol (trade name “C8GOL”, Exfloor) 1H, 1H-perfluoro-3,6,9-trioxatridecan-1-ol (trade name “C10GOL”, manufactured by Exfloor), 1H, 1H-perfluoro-3,6,9,12 -Tetraoxahexadecan-1-ol (trade name “C12GOL”, manufactured by Exfloor) and the like.
In this embodiment, it is preferable to use 1H, 1H-perfluoro-3,6,9,12-tetraoxatridecan-1-ol.

  Moreover, as a (meth) acrylic acid halide made to react 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 iodide can be mentioned. From the viewpoint of easy availability, (meth) acrylic acid chloride is preferred.

  Although the preferable specific example of a compound represented by a formula (F-3) below is shown, it is not limited to these. In addition, the preferable specific example represented by Formula (F-3) has description also in Unexamined-Japanese-Patent No. 2007-264221.

_{(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

  In addition to the compound represented by the formula (F-3), a compound represented by the following formula (F-3A) can also be preferably used.

Formula (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 each independently represent H, F, or CF ₃ is represented, a, b, and c each independently represent 0 or 1, and Rf ³ represents a fluorine-containing alkyl group containing an ether bond having 18 to 200 carbon atoms), and Rf ^{3 in the} group ,
Formula (FG-3A):
-(CX ⁶ ₂ CF ₂ CF ₂ O)-
(Wherein, X ⁶ is F or H) fluorine-containing unsaturated compound having 6 or more repeating units represented by.

As an example of the fluorine-containing polyether compound represented by the 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]
As the polymerizable unsaturated group of the fluorine-containing polyether compound, a group having the following structure is preferable. The definition of each symbol in (c-1) to (c-3) is synonymous with the formula (F-3A).

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

And the like are preferred. In the present embodiment, a compound having a structure of —O (C═O) CF═CH ₂ is preferable in that the polymerization (curing) reactivity is particularly high and a cured product can be obtained efficiently.

Rf ³ group in the fluorine-containing polyether compound represented by the formula (F-3A) is important to contain in 6 or more Rf ³ in the unit repeatedly fluoropolyether chain of formula (FG-3A) Thus, antifouling properties can be imparted.
More specifically, it may be a mixture in which the repeating unit of the fluorine-containing polyether chain contains 6 or more compounds. However, when used in the form of a mixture, the fluorine-containing unsaturated compound having less than 6 repeating units and 6 In a distribution with one or more fluorine-containing unsaturated compounds, a mixture having the highest abundance ratio of the fluorine-containing unsaturated compounds having 6 or more polyether chain repeating units is preferable.
The number of repeating units of the fluorine-containing polyether chain of the formula (FG-3A) is preferably 6 or more, more preferably 10 or more, still more preferably 18 or more, and particularly preferably 20 or more. Thereby, not only the water repellency but also the antifouling property, in particular, the removability to soils containing oil components can be improved. Moreover, gas permeability can be imparted more effectively. Further, the fluorine-containing polyether chain may be present at the end of the Rf ³ group or in the middle of the chain.

Specifically, the Rf ³ group is:
Formula (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), R ⁴ is selected from a hydrogen atom, a halogen atom or an alkyl group, a fluorine-containing alkyl group, an alkyl group containing an ether bond, and a fluorine-containing alkyl group containing an ether bond) And at least one kind, R ⁵ is a divalent or higher organic group, t is an integer of 6 to 66, and e is 0 or 1.
That is, it is a fluorine-containing organic group that is bonded to a reactive carbon-carbon double bond via a divalent or higher-valent organic group R ⁵ and further has R ⁴ at the terminal.
R ⁵ may be any organic group as long as it can bind the fluorine-containing polyether chain of the formula (FG-3A) to a reactive carbon-carbon double bond. For example, it is selected from an alkylene group, a fluorine-containing alkylene group, an alkylene group containing an ether bond and a fluorine-containing alkylene group containing an ether bond. Among these, a fluorine-containing alkylene group and a fluorine-containing alkylene group containing an ether bond are preferable in terms of transparency and low refractive index.

As specific examples of the fluorine-containing polyether compound represented by the formula (F-3A), compounds exemplified in WO2003 / 022906 pamphlet 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 used particularly preferably.

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

Formula (F-4): (Rf ¹ )-[(W)-(R _A ) _n ] _m
(In formula (F-4), Rf ¹ represents a (per) fluoroalkyl group or (per) fluoropolyether group, W represents a linking group, and _RA represents a functional group having an unsaturated double bond. -3, m represents an integer of 1-3, and n and m are not 1 at the same time.)
From the viewpoint of excellent water / oil repellency and excellent water / oil repellency (antifouling durability), n is preferably 2 to 3, m is preferably 1 to 3, and n is 2 to 3, and m is 2 It is more preferable that it is -3, and it is most preferable that n is 3, and m is 2-3.

  Rf¹May be a monovalent to trivalent group. Rf¹Is monovalent, the terminal group is (C_nF_{2n + 1})-, (C_nF_{2n + 1}O)-, (XC_nF_2nO)-, (XC_nF _{2n + 1})-(Wherein X is hydrogen, chlorine or bromine, and n is an integer of 1 to 10). Specifically, CF₃O (C₂F₄O)_pCF₂-, C₃F₇O (CF₂CF₂CF₂O)_pCF₂CF₂-, C₃F₇O (CF (CF₃CF₂O)_pCF (CF₃)-, F (CF (CF₃CF₂O)_pCF (CF₃)-Etc. can be preferably used.

  Here, the average value of p is 0-50. Preferably it is 3-30, More preferably, it is 3-20, Most preferably, it is 4-15.

If Rf ¹ is a _{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, the average value of q, r, and s is 0-50. Preferably it is 3-30, More preferably, it is 3-20, Most preferably, it is 4-15. t is an integer of 2-6.
A preferred specific example or synthesis method of the compound represented by the formula (F-4) is described in International Publication No. 2005/113690.

Hereinafter, a compound having an average value of p of 6 to 7 in F (CF (CF ₃ ) CF ₂ O) _p CF (CF ₃ ) — is referred to as “HFPO-”, and — (CF (CF ₃ ) CF _{2 O) p CF (CF 3} ) - a in the average value of p is 6-7 compounds described as "-HFPO-", shows the specific compounds of formula (F-4), but are not limited to.

_{(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): of _{HFPO-CONH-C 3 H 6} NHCH 3 trimethylolpropane triacrylate 1: 1 Michael addition polymers _{(d-4) :( CH 2} = CHCOOCH 2) 2 H-C-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

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

Formula (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 represents a C 2-20 fluoroalkyl group having 3 or more fluorine atoms or a carbon number having 4 or more fluorine atoms. 4 to 20 fluorocycloalkyl groups are shown.)

  In this embodiment, the compound whose polymerizable unsaturated group is a (meth) acryloyloxy group may have a plurality of (meth) acryloyloxy groups. Since the fluorine-containing antifouling agent has a plurality of (meth) acryloyloxy groups, when cured, it exhibits a three-dimensional network structure, a high glass transition temperature, and a low transferability of the antifouling agent. In addition, durability against repeated wiping of dirt can be improved. Furthermore, a cured film excellent in heat resistance, weather resistance and the like can be obtained.

  Specific examples of the compound represented by the formula (F-5) include, 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-undeca Fluorohexylethylene 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, di (meth) acrylic acid-1-methyl- Preferred examples include 2,2,3,3,3-pentafluoropropylethylene glycol and di (meth) acrylic acid-1-methyl-2,2,3,3,4,4,4-heptafluorobutylethylene glycol. It can be used alone or as a mixture. Such a di (meth) acrylic ester can be produced by a known method as described in JP-A-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 is Preferably used.

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

The fluorine-containing antifouling agent in this embodiment may be any of a monomer, an oligomer, or a polymer.
The fluorine-containing antifouling agent preferably further has a substituent that contributes to bond formation or compatibility in the hard coat layer film. These substituents may be the same or different, and a plurality of substituents are preferable. 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 fluorine-containing antifouling agent may be a polymer or an oligomer with a compound containing no fluorine atom.

  The fluorine-containing compound may contain a silicon atom in the molecule, may contain a siloxane structure, or may have a structure other than the siloxane structure. However, when the fluorine-containing compound having a polymerizable unsaturated group contains a siloxane structure, the weight average molecular weight is less than 15,000.

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

Formula (F-6):
R _a R ^f _b R ^A _c SiO _{(4-a-b-c) / 2}
(In the formula, 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, and R ^A is an organic group containing a polymerizable unsaturated group. Yes, 0 <a, 0 <b, 0 <c, a + b + c <4.)

  a is preferably 1 to 1.75, more preferably 1 to 1.5, and if it is 1 or more, the synthesis of the compound is industrially easy, and if it is 1.75 or less, curability and antifouling properties are obtained. Coexistence is easy.

The polymerizable unsaturated group in R ^A, include the same polymerizable unsaturated group and R _A in formula (F), in preferably (meth) acryloyl group, (meth) acryloyloxy group, and these groups A group in which an arbitrary hydrogen atom is substituted with a fluorine atom.

When the fluorine-containing compound contains a siloxane structure, a preferred example of the siloxane structure is a structure having a substituent at the terminal and / or side chain of a compound chain containing a plurality of dimethylsilyloxy units as repeating units. The compound chain containing dimethylsilyloxy as a repeating unit may contain a structural unit other than dimethylsilyloxy. The substituents may be the same or different, and a plurality of substituents are preferable. 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 Examples include a group containing a group, and a (meth) acryloyloxy group is particularly preferable from the viewpoint of suppressing bleed-out of the antifouling agent. The number of substituents is preferably 1500 to 20000 g · mol ⁻¹ as the functional group equivalent from the viewpoint of improving the uneven distribution of the antifouling agent and suppressing bleeding out.

R ^f is an organic group containing a fluorine atom, and is a group represented by C _x F _{2x + 1} (CH ₂ ) _p — (wherein x is an integer of 1 to 8, and p is an integer of 2 to 10). Or it is preferably a perfluoropolyether-substituted alkyl group. b is preferably 0.2 to 0.4, more preferably 0.2 to 0.25. When 0.2 or more, antifouling property is improved, and when 0.4 or less, curability is improved. To do. R ^f is preferably a C 8 perfluoroalkyl group.

R ^A is an organic group containing a (meth) acryl group, and the bond to the Si atom is more preferably a Si—O—C bond from the viewpoint of easy industrial synthesis. c is preferably 0.4 to 0.8, more preferably 0.6 to 0.8. When 0.4 or more, curability is improved, and when 0.8 or less, antifouling property is improved. To do.

  Further, a + b + c is preferably 2 to 2.7, more preferably 2 to 2.5. If it is less than 2, uneven distribution to the surface hardly occurs, and if it is more than 2.7, it is hardenable and antifouling. There is a tendency to be unable to achieve both.

  When the fluorine-containing compound contains a siloxane structure, the fluorine-containing compound has 3 or more F atoms and 3 or more Si atoms, preferably 3 to 17 F atoms and 3 to 8 Si atoms in one molecule. It is preferable to contain them. When there are 3 or more F atoms, the antifouling property is sufficient, and when there are 3 or more Si atoms, uneven distribution on the surface is promoted and the antifouling property is sufficient.

  When the fluorine-containing compound contains a siloxane structure, the fluorine-containing compound can be produced by using a known method described in JP-A-2007-14584.

  When the fluorine-containing compound contains a siloxane structure, the siloxane structure may be any of linear, branched, and cyclic, and among these, compounds having a branched or cyclic structure are particularly described below. It is preferable because it is compatible with a compound having a double bond, has no repelling, and tends to be unevenly distributed on the surface.

Here, the compound having a branched siloxane structure is preferably a compound represented by the following formula (F-7).
Formula (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 described above, and m = 0, 1, or 2, particularly m = 2, and k = 0 or 1.)

In addition, the compound having a cyclic structure of siloxane structure is preferably a compound represented by the following formula (F-8).
Formula (F-8):
(R ^f RSiO) (R ^A RSiO) _n (wherein R, R ^f , and R ^A are the same as described above, and n ≧ 2, particularly 3 ≦ n ≦ 5)

  The following compounds etc. are mentioned as a specific example of such a fluorine-containing polysiloxane compound.

The weight average molecular weight (Mw) of the fluorine-containing antifouling agent can be measured using molecular exclusion chromatography such as gel permeation chromatography (GPC). The Mw of the fluorine-containing 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. It is preferable that Mw is 400 or more because the surface migration property of the antifouling agent becomes high. Further, when the Mw is less than 5000, the surface migration of the fluorine-containing antifouling agent is not hindered during the process of curing from coating, and it is easy to orient uniformly on the hard coat layer surface. This is preferable because the hardness is improved.
However, when the fluorine-containing 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 fluorine-containing antifouling agent is preferably 1 to 20% by mass, more preferably 1 to 15% by mass with respect to the total solid content in the hard coat layer or the hard coat layer forming composition. More preferably, it is 10 mass%. When the addition amount of the fluorine-containing antifouling agent is 1% by mass or more with respect to the total solid content in the hard coat layer or the hard coat layer forming composition, the ratio of the antifouling agent having water and oil repellency is moderate. Thus, sufficient antifouling property can be obtained. Further, when the addition amount of the fluorine-containing antifouling agent is 20% by mass or less based on the total solid content in the hard coat layer or the hard coat layer forming composition, an antifouling agent that cannot be mixed with the resin component is deposited on the surface. The film is not whitened or white powder is not generated on the surface, which is preferable.

  Although there is no restriction | limiting in particular in fluorine atom content of a fluorine-containing antifouling agent, It is preferable that it is 20 mass% or more, It is especially preferable that it is 30-70 mass%, It is most 40-70 mass% preferable.

  Examples of preferred fluorine-containing antifouling agents include Daikin Chemical Industries, Ltd., R-2020, M-2020, R-3833, M-3833, OPTOOL DAC (trade name), DIC Corporation, MegaFac F- 171, F-172, F-179A, Defender MCF-300, MCF-323 (trade name) and the like, but are not limited thereto.

[Polysiloxane compound having a polymerizable unsaturated group and a weight average molecular weight of 15000 or more]
Next, a polysiloxane compound having a polymerizable unsaturated group and having a weight average molecular weight of 15000 or more that can be used as the component g) will be described. 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 formula (F-6).

Preferable examples of the polysiloxane antifouling agent include compounds having a substituent at the terminal and / or side chain of a compound chain containing a plurality of dimethylsilyloxy units as repeating units. The compound chain containing dimethylsilyloxy as a repeating unit may contain a structural unit other than dimethylsilyloxy. The substituents may be the same or different, and a plurality of substituents are preferable. 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 Examples include a group containing a group, and a (meth) acryloyloxy group is particularly preferable from the viewpoint of suppressing bleed-out of the antifouling agent. Further, the number of substituents is preferably 1500 to 20000 g · mol ⁻¹ as a functional group equivalent from the viewpoint of improving the uneven distribution of the antifouling agent and suppressing bleeding 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 in one molecule. . When there are 3 or more F atoms, the antifouling property is sufficient, and when there are 3 or more Si atoms, uneven distribution on the surface is promoted and the antifouling property is sufficient.

The polysiloxane antifouling agent can be produced using a known method described in JP-A No. 2007-14584.
Examples of the additive having a polysiloxane structure include 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 "(product name), “AK-5”, “AK-30”, “AK-32” (trade name), manufactured by Toa Gosei Co., Ltd .; “Silaplane FM0725”, “Silaplane FM0721” (Shin-Etsu Chemical Co., Ltd.) (Trade name), manufactured by JNC Corporation; “DMS-U22”, “RMS-033”, “UMS-182” (trade name), manufactured by Gelest, etc.} are also preferably added. Moreover, the silicone type compound of Table 2 or Table 3 of Unexamined-Japanese-Patent No. 2003-112383 can also be used preferably.

  The siloxane structure contained in the polysiloxane antifouling agent may be linear, branched, or cyclic, and among these, a compound having a branched or cyclic structure is an unsaturated double bond described later. It is preferable because it has good compatibility with a compound having an alkenyl group, has no repelling, and tends to be unevenly distributed on the surface.

The weight average molecular weight of the polysiloxane antifouling agent is 15000 or more, preferably 15000 or more and 50000 or less, more preferably 18000 or more and 30000 or less. If the weight average molecular weight of the polysiloxane antifouling agent is less than 15,000, the surface uneven distribution of the polysiloxane is reduced, which is not preferable from the viewpoint of causing deterioration of the antifouling property and a decrease in hardness. However, the above problem does not occur when the fluorine-containing compound having a polymerizable unsaturated group has a polysiloxane structure.
The weight average molecular weight of the polysiloxane antifouling agent can be measured using molecular exclusion chromatography such as gel permeation chromatography (GPC).

  The addition amount of the polysiloxane antifouling agent is preferably 1% by mass or more and less than 25% by mass with respect to the total solid content in the hard coat layer or the hard coat layer forming composition, and is preferably 1% by mass or more and 20% by mass. Is more preferable, 1 mass% or more and less than 15 mass% is still more preferable, and 1 mass% or more and less than 10 mass% is the 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 hard coat layer forming composition, the ratio of the antifouling agent having water and oil repellency is moderate. Thus, sufficient antifouling property can be obtained. Moreover, when the addition amount of the polysiloxane antifouling agent is less than 25% by mass with respect to the total solid content in the hard coat layer or the hard coat layer forming composition, an antifouling agent that cannot be mixed with the resin component is deposited on the surface. The film is not whitened or white powder is not generated on the surface, which is preferable.

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

g) The antifouling agent is preferably an antifouling agent that dissolves in a liquid or solvent at 20 ° C. The solvent can be appropriately selected depending on the polarity of the compound, but is preferably an organic solvent miscible with dimethyl carbonate, and examples thereof include aliphatic or aromatic alcohols, ketones, esters, and ether solvents. It is particularly preferred if it is dissolved in dimethyl carbonate.
g) From the viewpoint of antifouling properties, the surface tension of the antifouling agent is preferably 25.0 mN / m or less, more preferably 23.0 mN / m or less, and 16.0 mN / m. More preferably, it is as follows.
The surface tension of the antifouling agent is the surface tension of 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 was dried to produce a film. Subsequently, using a contact angle meter [“CA-X” type contact angle meter, manufactured by Kyowa Interface Science Co., Ltd.], using a pure water as a liquid in a dry state (20 ° C./65% RH), a diameter of 1 A droplet of 0.0 mm was formed on the needle tip, and this was brought into contact with the surface of the spin coat film to form a droplet on the film. The angle formed between the tangent to the liquid surface and the film surface at the point where the film and the liquid are in contact with each other, and the angle on the side containing the liquid was defined as the contact angle. Further, the contact angle was measured using methylene iodide instead of water, and the surface free energy was obtained from the following equation.
  Surface free energy (γs^v: Unit, mN / m). K. Owens: J.M. Appl. Polym. Sci. , 13, 1741 (1969) with reference to pure water H obtained experimentally on an antireflection film.₂O and methylene iodide CH₂I₂Each contact angle θ_H2O, Θ_CH2I2Γs obtained from the following simultaneous equations a and b^dAnd γs^hThe value γs expressed as the sum of^v(= Γs^d+ Γs^h).
a. 1 + cos θ_H2O= 2√γs^d(√γ_H2O ^d/ Γ_H2O ^v) + 2√γs^h(√γ _H2O ^h/ Γ_H2O ^v)
b. 1 + cos θ_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 the g) antifouling agent described above, a compound synthesized by a known method may be used, or a commercially available product may be used. As a commercial item, RS-90, RS-78, etc. by DIC can be used preferably.

(solvent)
The composition for forming a hard coat layer in the present embodiment may contain a solvent. The solvent is selected from the viewpoints of being able to dissolve or disperse each component, easily forming a uniform surface in the coating process and the drying process, ensuring liquid storage stability, having an appropriate saturated vapor pressure, and the like. Various solvents can be used.
The solvent can be used by mixing two or more kinds of solvents. In particular, from the viewpoint of drying load, it is preferable that the main component is a solvent having a boiling point of 100 ° C. or lower at normal pressure and room temperature, and a small amount of solvent having a boiling point of more than 100 ° C. is included for adjusting the drying speed.
In the composition for forming a hard coat layer in the present embodiment, it is preferable to contain 30-80% by mass of a solvent having a boiling point of 80 ° C. or less in the total solvent of the coating composition in order to prevent sedimentation of particles. More preferably, it is contained by mass. By setting the solvent ratio having a boiling point of 80 ° C. or less to the above ratio, the resin component can be appropriately prevented from permeating into the polyester film, and the rate of increase in viscosity due to drying can be increased, thereby suppressing particle sedimentation.

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

  Examples of the solvent having a boiling point exceeding 100 ° C. include 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.), Examples thereof include 1-butanol (117.7 ° C.), N, N-dimethylformamide (153 ° C.), N, N-dimethylacetamide (166 ° C.), dimethyl sulfoxide (189 ° C.) and the like. Cyclohexanone and 2-methyl-4-pentanone are preferable.

(Surfactant)
In the present embodiment, it is also preferable to use various surfactants and / or wind unevenness inhibitors (hereinafter, collectively referred to as surfactants) in the hard coat layer or the hard coat layer forming composition. In general, surfactants and / or wind unevenness inhibitors can suppress film thickness unevenness due to drying variations due to local distribution of dry air.

  Specifically, the surfactant preferably contains a fluorine-based surfactant, a silicone-based surfactant, or both. Further, the surfactant is preferably an oligomer or a polymer rather than a low molecular compound.

  Preferable examples of the fluorosurfactant include a fluoroaliphatic group-containing copolymer (hereinafter sometimes abbreviated as “fluorine polymer”), and the fluoropolymer includes the following (i): An acrylic resin, a methacrylic resin, and a copolymerizable copolymer containing a repeating unit corresponding to the monomer or a repeating unit corresponding to the monomer (i) and a repeating unit corresponding to the monomer (ii) below. Copolymers with vinyl monomers are useful.

(I) Fluoroaliphatic group-containing monomer represented by the following formula (i) Formula (i)

In the 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 1-6, and n is an integer of 2-4. 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, preferably a hydrogen atom or a methyl group. X is preferably an oxygen atom.

(Ii) Monomer represented by the following formula (ii) copolymerizable with the above (i): Formula (ii)

In the formula (ii), R ¹³ represents a hydrogen atom or a methyl group, Y represents an oxygen atom, a sulfur atom or —N (R ¹⁵ ) —, R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Specifically, it represents a methyl group, an ethyl group, a propyl group or a butyl group, preferably a hydrogen atom or a methyl group. Y is an oxygen atom, -N (H) -, and -N (CH ₃₎ - are preferred.
R ¹⁴ represents a linear, branched or cyclic alkyl group having 4 to 20 carbon atoms which may have a substituent. Examples of the substituent for the alkyl group represented by 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. , Amino groups and the like, but not limited thereto. Examples of the linear, branched or cyclic alkyl group having 4 to 20 carbon atoms include a butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and undecyl group which may be linear or branched. , Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, octadecyl group, eicosanyl group, etc., and monocyclic cycloalkyl groups such as cyclohexyl group, cycloheptyl group and bicycloheptyl group, bicyclodecyl group, tricycloundecyl group, A polycyclic cycloalkyl group such as a tetracyclododecyl group, an adamantyl group, a norbornyl group, a tetracyclodecyl group, or the like is preferably used.

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

  The preferred weight average molecular weight of the fluoropolymer is preferably 3000 to 100,000, more preferably 5,000 to 80,000. Furthermore, the preferable addition amount of a fluorine-type polymer is the range of 0.001-5 mass parts with respect to 100 mass parts of coating liquids, More preferably, it is the range of 0.005-3 mass parts, More preferably, it is 0. .01 to 1 part by mass. If the addition amount of the fluorine-based polymer is 0.001 part by mass or more, the effect of adding the fluorine-based polymer is sufficiently obtained, and if the addition amount is 5 parts by mass or less, the coating film cannot be sufficiently dried or applied. There is no problem of adversely affecting the performance as a film.

Examples of preferred silicone compounds include X-22-174DX, X-22-2426, X22-164C, X-22-176D (above trade names) manufactured by Shin-Etsu Chemical Co., Ltd .; manufactured by JNC Corporation. FM-7725, FM-5521, FM-6621 (trade name); DMS-U22 manufactured by Gelest, RMS-033 (trade name); SH200, DC11PA, ST80PA, L7604 manufactured by Toray Dow Corning Co., Ltd. FZ-2105, L-7604, Y-7006, SS-2801 (trade name); TSF400 (trade name) manufactured by Momentive Performance Materials Japan, and the like, but are not limited thereto.
The silicone surfactant is preferably contained in an amount of 0.01 to 0.5% by mass when the total solid content of the hard coat layer forming composition in the present embodiment is 100% by mass. -0.3 mass% is more preferable.

(Matte particles)
The hard coat layer or the hard coat layer forming composition has a mean particle size of 1.0 to 15.0 μm, preferably 1.5 to 10.0 μm, for the purpose of imparting internal scattering properties or surface irregularities. It may contain. Moreover, in order to adjust the viscosity of a coating liquid, a high molecular compound, an inorganic layered compound, etc. can also be included. e) may be used as matte particles.

The hard coat film according to one aspect of the present disclosure may include other layers (arbitrary layers) in addition to the polyester film and the hard coat layer according to the embodiment described above. Examples of such an arbitrary layer include an easy adhesion 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, and the like. However, it is not limited to these. For these optional layers, reference can be made to paragraphs 0069 to 0091 of Japanese Patent No. 5048304, for example. Moreover, you may provide a decoration layer in the hard coat film which concerns on this embodiment.
Although the example of the preferable layer structure of the hard coat film which concerns on this embodiment is shown below, it is not necessarily limited only to these layer structures.
Polyester film / hard coat layerPolyester film / hard coat layer / low refractive index layerPolyester film / hard coat layer / antiglare layer (antistatic layer) / low refractive index layer
・ Polyester film / hard coat layer / antiglare layer / antistatic layer / low refractive index layer,
・ Polyester film / hard coat layer / antistatic layer / antiglare layer / low refractive index layer,
・ Polyester film / hard coat layer (antistatic layer) / antiglare 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 hard coat properties.

(Low refractive index layer)
In the hard coat film according to the present embodiment, a low refractive index layer can be formed on the hard coat layer for the purpose of providing a reflectance reduction effect. The low refractive index layer has a refractive index lower than that of 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 1.30 to 1. .40 is particularly preferred.
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 the low refractive index layer.
As a preferred embodiment of the curable composition of the low refractive index layer,
(1) A composition containing a fluorine-containing compound having a crosslinkable or polymerizable functional group,
(2) a composition comprising as a main component a hydrolysis-condensation product of a fluorine-containing organosilane material;
(3) a composition containing a monomer having two or more ethylenically unsaturated groups and inorganic particles (in particular, inorganic particles having a hollow structure are preferred);
Etc.
Regarding each of the compositions (1) and (2), it is preferable to contain inorganic particles, and when inorganic particles having a hollow structure with a low refractive index are used, the refractive index is lowered or the amount of inorganic particles added and the refraction. It is particularly preferable from the viewpoint of adjusting the rate.

(1) Composition containing a fluorine-containing compound having a crosslinkable or polymerizable functional group As the fluorine-containing compound having a crosslinkable or polymerizable functional group, a fluorine-containing monomer and a crosslinkable or polymerizable functional group are used. Mention may be made of a fluorine-containing polymer which is a copolymer with the monomer it has. Specific examples of these fluoropolymers are described in JP2003-222702A, JP2003-183322A, and the like.

  The fluoropolymer may be used in combination with a curing agent having a polymerizable unsaturated group as appropriate, as described in JP-A No. 2000-17028. Moreover, combined use with a compound having a fluorine-containing polyfunctional polymerizable unsaturated group as described in JP-A No. 2002-145952 is also preferred. Examples of the compound having a polyfunctional polymerizable unsaturated group include monomers having two or more ethylenically unsaturated groups described as the curable resin compound for the low refractive index layer. Moreover, the hydrolysis-condensation product of the organolane described in Unexamined-Japanese-Patent No. 2004-170901 is also preferable, and the hydrolysis-condensation product of the organosilane containing a (meth) acryloyl group is especially preferable. These compounds are preferred because they have a large combined effect for improving scratch resistance, particularly when a compound having a polymerizable unsaturated group is used in the polymer body.

  When the polymer itself does not have sufficient curability, necessary curability can be imparted by blending a crosslinkable compound. For example, when the polymer body contains a hydroxyl group, various amino compounds are preferably used as the curing agent. The amino compound used as the crosslinkable compound is, for example, a compound containing one or both of a hydroxyalkylamino group and an alkoxyalkylamino group in total, specifically, for example, a melamine compound, Examples include urea compounds, benzoguanamine compounds, glycoluril compounds, and the like. For curing these compounds, an organic acid or a salt thereof is preferably used.

(2) Composition mainly composed of hydrolyzed condensate of fluorine-containing organosilane material The composition mainly composed of hydrolyzed condensate of fluorine-containing organosilane compound also has a low refractive index and the hardness of the coating film surface Is preferable. A condensate of a tetraalkoxysilane with a hydrolyzable silanol-containing compound at one or both ends with respect to the fluorinated alkyl group is preferred. Specific compositions are described in JP-A Nos. 2002-265866 and 317152.

(3) A composition containing a monomer having two or more ethylenically unsaturated groups and inorganic particles having a hollow structure As still another preferred embodiment, a low refractive index layer comprising a low refractive index particle and a resin can be mentioned. . The low refractive index particles may be organic or inorganic, but particles having pores inside are preferable. Specific examples of the hollow particles include silica-based particles described in JP-A No. 2002-79616. 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 antiglare layer.

  It is preferable to add a photoradical polymerization initiator or a thermal radical polymerization initiator to the composition for forming a low refractive index layer used in the present embodiment. When a radically polymerizable compound is contained, 1 to 10 parts by mass, preferably 1 to 5 parts by mass of a polymerization initiator can be used with respect to the above compound.

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

  The low refractive index layer used in the present embodiment is a known polysiloxane-based or fluorine-based antifouling agent or slipping agent for the purpose of imparting antifouling properties, water resistance, chemical resistance, slipping properties and the like. Etc. can be suitably added.

  As an additive having a polysiloxane structure, a reactive group-containing polysiloxane {for example, 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 (trade name), manufactured by Shin-Etsu Chemical Co., Ltd .; AK-5, AK-30, AK- 32 (trade name), manufactured by Toa Gosei Co., Ltd .; “Silaplane FM0725”, “Silaplane FM0721” (trade name), manufactured by JNC Co., Ltd., etc.} are also preferably added. Moreover, the silicone type compound of Table 2 and Table 3 of Unexamined-Japanese-Patent No. 2003-112383 can also be used preferably.

  As the fluorine compound, a compound having a fluoroalkyl group is preferable. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and a straight chain (for example, -CF₂CF₃, -CH₂(CF₂)₄H, -CH₂(CF₂)₈CF₃, -CH₂CH₂(CF₂)₄H or the like, but also a branched structure (for example, CH (CF₃)₂, CH₂CF (CF₃)₂, CH (CH₃CF₂CF₃, CH (CH₃) (CF₂)₅CF ₂H) or an alicyclic structure (preferably a 5-membered or 6-membered ring such as a perfluorocyclohexyl group, a perfluorocyclopentyl group, or an alkyl group substituted with these). May have an ether bond (for example, CH₂OCH₂CF₂CF₃, CH₂CH₂OCH₂C₄F₈H, CH₂CH₂OCH₂CH₂C₈F₁₇, CH₂CH₂OCF₂CF₂OCF₂CF₂H 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 bond formation or compatibility with the low refractive index layer film. The above substituents may be the same or different, and a plurality of substituents are preferable. 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 the molecular weight is not particularly limited. Although there is no restriction | limiting in particular in fluorine atom content of a fluorine-type compound, It is preferable that it is 20 mass% or more, It is especially preferable that it is 30-70 mass%, It is most preferable that it is 40-70 mass%. Examples of preferred fluorine-based compounds include Daikin Chemical Industries, Ltd., R-2020, M-2020, R-3833, M-3833, Optool DAC (named above), DIC Corporation, MegaFuck F-171, Examples include, but are not limited to, F-172, F-179A, defender MCF-300, MCF-323 (trade name) and the like.
These polysiloxane fluorine-based compounds or compounds having a polysiloxane structure are preferably added in the range of 0.1 to 10% by mass, particularly preferably 1 to 5% by mass of the total solid content of the low refractive index layer. It is.

[Method of applying 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 dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, die coating, etc., and heated. ·dry. A micro gravure coating method, a wire bar coating method, and a die coating method (see US Pat. No. 2,681,294 and JP-A-2006-122889) are more preferable, and a die coating method is particularly preferable.

  After the hard coat layer is coated on the base film, it is conveyed by a web to a heated zone to dry the solvent. In this case, the temperature of the drying zone 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 preferably below the temperature at which components other than the solvent contained in the coating composition of each layer start to volatilize. For example, some of the commercially available photo radical generators used in combination with ultraviolet curable resins volatilize around several tens of percent within a few minutes in warm air at 120 ° C. Some acrylate monomers and the like undergo volatilization in warm air at 100 ° C. In such a case, as described above, the temperature is preferably equal to or lower than the temperature at which components other than the solvent contained in the hard coat layer coating composition start to volatilize.

Moreover, the drying wind after apply | coating the coating composition of a hard-coat layer on a base film has a wind speed of the coating-film surface of 0.1-2 m while the solid content concentration of the said coating composition is 1-50%. / Second is preferable in order to prevent unevenness in drying.
In addition, after the coating composition of the hard coat layer is coated on the base film, the temperature difference between the transport roll and the base film contacting the surface opposite to the coating surface of the base film in the drying zone is 0 ° C. When the temperature is within -20 ° C, drying unevenness due to heat transfer unevenness on the transport roll can be prevented, which is preferable.

After the solvent drying zone, the web is passed through a zone where the hard coat layer is cured by irradiation with ionizing radiation, and the coating film is cured. For example, if the coating film is ultraviolet-curable, preferably to cure the coating by an irradiation amount of 10mJ ^/ cm ² ~1000mJ ^/ cm 2 by an ultraviolet lamp. At that time, the irradiation distribution in the width direction of the web is preferably 50 to 100%, more preferably 80 to 100%, including both ends with respect to the central maximum irradiation. Further, when it is necessary to purge nitrogen gas or the like to lower the oxygen concentration in order to promote surface hardening, the oxygen concentration is preferably 0.01% to 5%, and the distribution in the width direction is 2% or less in terms of oxygen concentration. Is preferred. In the case of ultraviolet irradiation, ultraviolet rays emitted from light such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, etc. can be used. Moreover, in order to accelerate | stimulate hardening reaction, temperature can also be raised at the time of hardening, 25-100 degreeC is preferable, More preferably, it is 30-80 degreeC, Most preferably, it is 40-70 degreeC.

  Further, other functional layers can be provided as necessary. When other functional layers are laminated in addition to the hard coat layer, a plurality of layers may be applied simultaneously or 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 can be suitably used for uses that are required to suppress the formation of recesses when a load is applied.
The polyester film which concerns on this embodiment can be used suitably as a base film of various functional films, such as a sensor film for touch panels, a scattering prevention film, an antireflection film other than the base film of a hard coat film, for example.

[Anti-scattering film]
The scattering prevention film according to this embodiment is a scattering prevention film in which an adhesive layer is laminated on at least one surface of the polyester film according to this embodiment. The polyester film according to this embodiment can be used as a scattering prevention film. In the anti-scattering film, it is preferable that a hard coat layer and an adhesive layer are laminated on a polyester film.
The adhesive layer may be formed by either a wet coating method or a dry coating method. To form the adhesive layer, an acrylic adhesive composition such as a solvent-based acrylic polymer or solvent-based acrylic syrup, solvent-free acrylic syrup, or solvent-free urethane acrylate can be used.

[Antireflection film]
The antireflection film according to this embodiment is an antireflection film in which an antiglare layer is laminated on at least one surface of the polyester film according to this embodiment. The polyester film according to this embodiment can be used for an antireflection film.
The antiglare layer may be formed by either a wet coating method or a dry coating method. For the antiglare layer, JP-A-2014-059334, JP-A-2014-026122, JP-A-2014-016602, JP-A-2014-016476, JP-A-2014-041206, JP-A-2014-032317, JP-A-2014-026123, JP-A The anti-glare layer described in 2014-010316 can be used.

[Sensor film for touch panel]
The sensor film for a touch panel according to the present embodiment is a sensor film for a touch panel including 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. In the sensor film for a touch panel, it is preferable that a hard coat layer and a transparent conductive layer are laminated on a polyester film.
Common methods for forming a transparent conductive layer include PVD (Physical Vapor Deposition) methods such as sputtering, vacuum deposition, and ion plating, or CVD (Chemical Vapor Deposition), coating, and printing. is there. The material for forming the transparent conductive layer is not particularly limited, and examples thereof include indium / tin composite oxide (ITO), tin oxide, copper, silver, aluminum, nickel, and chromium. May be formed.
Moreover, before forming a transparent conductive layer, the undercoat layer for improving transparency or an optical characteristic may be provided. In order to further improve the 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 desirable 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 apparatus according to the present embodiment includes an image display element and the hard coat film according to the present embodiment, and the hard coat film is disposed on the outermost surface.
Examples of the image display device according to this 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.

As the liquid crystal display device, a TN (Twisted Nematic) type, an STN (Super-Twisted Nematic) type, a TSTN (Triple Super Twisted Nematic) type, a multi-domain type, a VA (Vertical Alignment In) type, an IPS type, an IPS 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 the hard coat film according to the present embodiment is disposed on the outermost surface. An apparatus is preferred. In this case, the image display element is a liquid crystal display element.

  In the image display device according to the present embodiment, the image display element is also preferably 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 this embodiment can be applied is not particularly limited and can be appropriately selected depending on the purpose. For example, a surface capacitive touch panel, a projected capacitive touch panel, a resistive touch panel, and the like can be given. Details will be described later as the resistive touch panel according to the present embodiment and the capacitive touch panel according to the present embodiment.
The touch panel includes so-called touch sensors and touch pads. 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 surfaces of a single substrate, a single-sided jumper or through-hole method, or a single-area layer method. Either is acceptable. In addition, the projected capacitive touch panel is preferably AC (Alternating Current) drive than DC (Direct Current) drive, and more preferably a drive 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.
The resistive touch panel has a basic configuration in which a conductive film of a pair of upper and lower substrates having a conductive film is disposed via a spacer so that the conductive films face each other. The configuration of the resistive film type touch panel is well known, and any known technique can be applied without any limitation in the present embodiment.

(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.
Examples of the capacitive touch panel system include a surface capacitive type and a projected capacitive type. The projected 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 arranged via an insulator. As a specific aspect, an aspect in which the X electrode and the Y electrode are formed on different surfaces on one substrate, an aspect in which the X electrode, the insulator layer, and the Y electrode are formed in this order on the single substrate. Examples include an embodiment in which an X electrode is formed on one substrate and a Y electrode is formed on another substrate (in this embodiment, a configuration in which two substrates are bonded together is the above basic configuration). The configuration of the capacitive touch panel is known, and any known technique can be applied without any limitation in the present embodiment.

The present disclosure will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present disclosure. Therefore, the scope of the present disclosure is not construed as being limited by the specific examples shown below.
Unless otherwise specified, “parts” and “ppm” are based on mass.

[Example 1]
<Synthesis of raw material polyester>
(Raw material polyester 1)
As shown below, terephthalic acid and ethylene glycol are directly reacted to distill off water, esterify, and then, using a direct esterification method in which polycondensation is performed under reduced pressure, raw 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 are mixed over 90 minutes to form a slurry, and continuously into the first esterification reactor at a flow rate of 3800 kg / h. Supplied. Further, an ethylene glycol solution of antimony trioxide was continuously supplied, and the reaction was carried out at a reaction vessel temperature of 250 ° C. with 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 element.

  This reaction product was transferred to a second esterification reaction vessel, and reacted with stirring at a temperature in the reaction vessel of 250 ° C. and an average residence time of 1.2 hours. The second esterification reaction tank is continuously supplied with an ethylene glycol solution of magnesium acetate and an ethylene glycol solution of trimethyl phosphate so that the Mg addition amount and the P addition amount are 65 ppm and 35 ppm in terms of element, respectively. did.

(2) the polycondensation reaction above-obtained esterification reaction product supplied to the first polycondensation reaction vessel continuously stirring, the reaction temperature 270 ° C., the reaction vessel pressure 20 torr (2.67 × 10 ^{- 3} MPa) and polycondensation with an average residence time of about 1.8 hours.

Further, it was transferred to the second double condensation reaction tank, and while stirring in this reaction tank, the reaction tank temperature was 276 ° C., the reaction tank pressure was 5 torr (6.67 × 10 ⁻⁴ MPa), and the residence time was about 1.2 hours. The reaction (polycondensation) was performed under the conditions.

Subsequently, it was further transferred to the third triple condensation reaction tank. In this reaction tank, the reaction tank temperature was 278 ° C., the reaction tank internal pressure was 1.5 torr (2.0 × 10 ⁻⁴ MPa), and the residence time was 1.5 hours. The reaction product (polyethylene terephthalate; PET) was obtained by reaction (polycondensation) under the following conditions.

  Next, the obtained reaction product was discharged into cold water in the form of a strand and immediately cut to prepare a polyester pellet “cross section: major axis about 4 mm, minor axis about 2 mm, length: about 3 mm”.

  The obtained polyester had IV = 0.63. This polyester was designated as polyester 1.

<Manufacture of polyester film>
-Film forming process-
After the raw material polyester 1 was dried to a water content of 20 ppm or less, it was put into a hopper 1 of a uniaxial kneading extruder 1 having a diameter of 50 mm. The raw material polyester 1 was melted at 300 ° C. and extruded from a die through a gear pump and a filter (pore diameter: 20 μm) under the following extrusion conditions.
The molten resin was extruded from the die under the conditions that the pressure fluctuation was 1% and the temperature distribution of the molten resin was 2%. Specifically, the back pressure was increased 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 onto a cooling cast drum set at a temperature of 25 ° C., and adhered to the cooling cast drum using an electrostatic application method. It peeled using the peeling roll arrange | positioned facing the cooling cast drum, and the unstretched polyester film 1 was obtained.

-Formation of an easy adhesion layer-
The following compounds were mixed at the following ratio to prepare a coating liquid H1 for forming an easy adhesion layer.

(Coating liquid H1 for easy adhesion 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 Details of the compounds used for forming the easy adhesion layer are shown below. .

Polyester resin: (IC)
A sulfonic acid aqueous dispersion of a polyester resin copolymerized with monomers having 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)
Aqueous dispersion of acrylic resin polymerized with monomers of the following composition Ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2/2 (mass%) emulsion polymer ( Emulsifier: Anionic surfactant)

  Melamine compound: (VIB) hexamethoxymethylmelamine

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

-Application of easy adhesion layer to one side of polyester film-
Using the wire bar while adjusting the coating liquid H1 for forming an easy-adhesion layer on one side of the unstretched polyester film 1 so that the coating film thickness after stretching is 65 nm by a bar coating method using a wire bar. Applied.

-Transverse stretching process-
The unstretched polyester film 1 was guided to a tenter (transverse stretching machine), and was stretched laterally by the following method and conditions while holding the end of the film with a clip.

(Preheating part)
It heated with the hot air so that the surface temperature in the extending | stretching start point might be 89 degreeC.
In addition, the surface temperature at the stretching start point is a radiation thermometer (manufactured by Hayashi Denko, model number: RT61-2, used at an emissivity of 0.95) at the center of the film width direction at the point of starting stretching. It was measured by.

(Extension part)
While preheated unstretched polyester film 1 was heated with hot air, it was stretched in the width direction (TD) using a tenter under the following conditions.
In addition, the surface temperature in each draw ratio time point is a radiation thermometer (used by Hayashi Denko, model number: RT61-2, emissivity 0.95) at the center of the film width direction at each draw ratio time point. It was measured by.

<Condition>
・ Horizontal stretch ratio: 4.1 times and surface temperature at the time of 2 times stretch: 90 ° C
-Surface temperature at the time of 3 times stretching: 94 ° C
-Surface temperature at the end of stretching: 95 ° C

(Heat fixing part and heat relaxation part)
Subsequently, hot fixing from the up-down direction was applied to the film from the hot air blowing nozzle to the film, and heat fixing and heat relaxation treatment were performed while controlling the surface temperature of the polyester film within the following range.

<Condition>
Maximum surface temperature (heat setting temperature): 185 ° C
-Thermal relaxation rate: MD4%, TD1.5%

(Cooling section)
Next, the film was cooled by applying cold air from above and below to the film from a cold air blowing nozzle. The film was cooled so that the surface temperature when the film was released from the tenter clip was 40 ° C.
In addition, the surface temperature measured the position of the center part of a film width direction with the radiation thermometer (The Hayashi Denko make, model number: RT61-2, used by the emissivity 0.95).

(Recovery of film)
After cooling and releasing the film from the clip, both ends of the polyester film were trimmed by 20 cm. The film width after trimming was 2 m. Then, after extruding (knurling) with a width of 10 mm at both ends, a film having a length of 10,000 m was wound up in a roll form with a tension of 18 kg / m.
As described above, the polyester film of Example 1 having a thickness of 200 μm wound in a roll form was produced.

[Examples 2-11, 13, 14 and Comparative Examples 1-3, 5]
In Example 1, the conditions of the transverse stretching process, the easy-adhesion layer, and the hard coat layer were the same as in Example 1 except that the polyesters of the examples and comparative examples were changed as described in Table 1 below. A film was produced.

[Example 12, Comparative Example 4]
A polyester film of Example 12 was produced in the same manner as Example 1 except that the easy adhesion layer was not provided.
Moreover, the polyester film of the comparative example 4 was manufactured like Example 1 except having changed the conditions and film thickness of the horizontal extending | stretching process as described in following Table 1, and not providing an easily bonding layer. In Comparative Example 4, a polyester film was produced by a similar method based on the description in Example 2 of JP2012-230390A.

[Film measurement results]
The following physical properties were measured for the films obtained in each example. The measurement results are shown in Table 1 below.

<Thickness>
The thickness of the polyester film of each Example and Comparative Example obtained was determined as follows.
Using a contact-type film thickness meter (manufactured by Anritsu) for the polyester film of each example and comparative example, 50 points were sampled at equal intervals over 0.5 m in the longitudinally stretched direction (longitudinal direction). After sampling 50 points at equal intervals (50 equal parts in the width direction) over the entire width of the film in the film width direction (direction perpendicular to the longitudinal direction), the thicknesses of these 100 points were measured. The average thickness of these 100 points was determined and used as the thickness of the polyester film.

<Re, Rth, Re / Rth ratio>
Re and Rth of the film obtained in each example were determined by the method described above. From the obtained Re and Rth, the Re / Rth ratio was calculated.

<Shear plane normal stress and shear plane yield stress>
Using the SAICAS-NN type (manufactured by Daipura Wintes Co., Ltd.) for the obtained polyester films of each Example and Comparative Example, the shear surface normal stress and shear surface yield stress of the film surface layer of 1 μm were respectively determined by the methods described above. It was measured.
From the measured values, the average value of the shear plane normal stress A in the slow axis direction in the surface layer of 1 μm and the shear plane normal stress B in the direction perpendicular to the slow axis direction (fast axis direction) in the film plane is calculated. Calculated. Here, TD is the slow axis direction of the film, and MD is the fast axis direction of the film.

[Preparation of hard coat film]
A coating liquid for forming a hard coat layer having the following composition was prepared.
・ Cyclomer M100: 3,4-epoxycyclohexylmethyl methacrylate (manufactured by Daicel Corporation) 40 parts by mass ・ DPHA: KAYARD DPHA (manufactured by Nippon Kayaku Co., Ltd.) 55.4 parts by mass ・ Irgacure 127: alkylphenone photopolymerization started Agent (BASF (manufactured)) 2.5 parts by mass-Irgacure 290: Sulfonium salt cationic polymerization initiator (BASF (manufactured)) 2.0 parts by mass-Wind unevenness inhibitor FP-1: Fluorine-containing compound having the following structure 1 part by mass / solvent 1 MEK 100 parts by mass / solvent 2 MIBK 50 parts by mass

The uniaxially stretched polyester films wound up in the form of rolls were unwound and applied as a post-process by applying the hard coat layer forming coating solution by the following method.
The coating liquid for forming a hard coat layer is a die coating method using a slot die described in Example 1 of JP-A-2006-122889 on one side of the film (when the easy-adhesion layer is provided), a conveyance speed of 30 m The coating was performed under the conditions of / min. After drying at 60 ° C. for 150 seconds, using an air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% under a nitrogen purge, an illuminance of 400 mW / cm ² and an irradiation amount of 500 mJ The coating layer (hard coat layer) was cured by irradiating with / cm ² of ultraviolet rays and wound up.

<Film thickness of hard coat layer>
When the polyester film obtained in Examples other than Example 9 or Comparative Examples is used, the thickness of the hard coat layer is 22 μm. When the polyester film obtained in Example 9 is used, the hard coat layer The thickness was 5 μm.
The film thickness of the hard coat layer was calculated by measuring the film thickness of the hard coat film prepared with a contact-type film thickness meter, and subtracting the thickness of the polyester film measured in the same manner.

[Evaluation]
The following evaluation was performed about the hard coat film obtained by each Example and the comparative example. The evaluation results are shown in Table 1 below.

<Punching evaluation>
The hard coat film was punched 10 times, and the crack / peeling state of the hard coat on the punched end face was evaluated according to the following criteria.
A: No cracking / peeling B: Cracking / peeling occurs only once C: Cracking / peeling occurs 2-3 times D: Cracking / peeling occurs 4 times or more

<Surface deformation evaluation>
A dent when the hard coat film surface (hard coat layer side) was pressed with a force of 10 N / mm ² with an iron brush was observed and evaluated according to the following criteria.
A: No dent occurs at all. B: The dent is not visually recognized, but can be recognized by microscopic observation. C: The dent is slightly visible. D: The dent is clearly visible.

<Visibility evaluation>
A hard coat film was sandwiched between polarizing plates installed in crossed Nicols so that the orientation angle was inclined by 45 ° with respect to the absorption axis of the polarizing plate, and the LED backlight was illuminated from the back, and the visibility was evaluated according to the following criteria. .
A: Rainbow unevenness is not visible at all B: Rainbow unevenness is hardly visible C: Rainbow unevenness is slightly visible but acceptable
D: Rainbow unevenness looks strong

The meanings of the symbols in Table 1 are as follows.
・ DPHA: KAYARD DPHA (manufactured by Nippon Kayaku Co., Ltd.)
3,4-epoxy CHMA: 3,4-epoxycyclohexylmethyl acrylate 3,4-epoxy CHMM: 3,4-epoxycyclohexylmethyl methacrylate IRG127: Irgacure 127 (alkylphenone photopolymerization initiator, manufactured by BASF)
IRG290: Irgacure 290 (sulfonium salt-based cationic polymerization initiator, manufactured by BASF)
RS-90: (Anti-fouling agent, manufactured by DIC Corporation)

  As is clear from Table 1 above, the hard coat film of the example suppressed both the occurrence of cracks and peeling of the hard coat layer and the occurrence of dents as compared with the hard coat film of the comparative example.

The disclosure of Japanese Patent Application No. 2016-026351 filed on February 15, 2016 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

10 Cutting blade 12 Polyester film 20 Clip (gripping member)

Claims (17)

  The average value of the shear plane normal stress A in the slow axis direction in the surface layer of 1 μm and the shear plane normal stress B in the direction perpendicular to the slow axis direction in the film plane is 30 to 100 MPa. Some polyester film.   The polyester film according to claim 1, which is used for a base film of a hard coat film.   The polyester film according to claim 1, which is a uniaxially oriented polyester film.   The polyester film according to any one of claims 1 to 3, wherein an in-plane retardation Re of the polyester film at a measurement wavelength of 589 nm is 4000 to 50000 nm.   The average value of the shear plane yield stress in the slow axis direction in the surface layer of 1 μm of the polyester film and the shear plane yield stress in the direction perpendicular to the slow axis direction in the film plane is 20 to 60 MPa. Item 5. The polyester film according to any one of Items 4.   The polyester film according to any one of claims 1 to 5, wherein a ratio of the shear surface normal stress A to the shear surface normal stress B is 1.1 to 2.0.   The ratio of retardation Re in the film surface to retardation Rth in the film thickness direction at a measurement wavelength of 589 nm of the polyester film is 0.6 to 1.2. 7. Polyester film. A base film comprising the polyester film according to any one of claims 1 to 7,
A hard coat layer laminated on at least one side of the base film;
Hard coat film having   The hard coat film according to claim 8, wherein the hard coat layer has a thickness of 5 μm or more. The hard coat layer is
At least a structure derived from a) below, a structure derived from b) below, c) and d) below,
When the hard coat layer has a total solid content of the hard coat layer of 100% by mass, the structure derived from a) below is 15 to 70% by mass, the structure derived from b) below is 25 to 80% by mass, and the following c The hard coat film of Claim 8 or Claim 9 containing 0.1-10 mass% of following d) 0.1-10 mass%.
a) a compound having one alicyclic epoxy group and one group containing an ethylenically unsaturated double bond in the molecule and having a molecular weight of 300 or less; b) three or more ethylenic groups in the molecule. Compound having group containing saturated double bond c) radical polymerization initiator d) cationic polymerization initiator   The image display apparatus containing the image display element and the hard coat film of any one of Claims 8-10, and the said hard coat film is arrange | positioned at the outermost surface.   A touch panel comprising the hard coat film according to any one of claims 8 to 10, wherein the hard coat film is disposed on an outermost surface. Using a lateral stretching device provided with a plurality of clips respectively traveling along a pair of rails installed on both sides of the film conveyance path,
A preheating step of preheating an unstretched or longitudinally stretched polyester film at a heating rate of 600 ° C./min or less;
The polyester film is stretched in the direction perpendicular to the film conveying path in a state where both edges of the preheated polyester film are gripped by the plurality of clips, and from the start of the transverse stretching to the end of the transverse stretching. The surface temperature at the start of the transverse stretching is controlled to 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 stretching is performed. A transverse stretching step of controlling the magnification within a range of 3.3 times to 4.8 times;
A heat setting step of heat-setting the polyester film after the transverse stretching step by heating to a maximum temperature in the transverse stretching apparatus,
The manufacturing method of the polyester film which manufactures the polyester film whose thickness is 40-500 micrometers. In the transverse stretching step, the surface temperature is gradually increased at a temperature increase rate of 60 ° C./min or less,
The surface temperature when the transverse draw ratio is in the range of 1 to 2 times is 80 ° C. or more and 92 ° C. or less,
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
The manufacturing method of the polyester film of Claim 13 which controls the said surface temperature when the said horizontal draw ratio is the range of 3 times or more to 90 to 102 degreeC. The temperature increase rate of the surface temperature of the polyester film from the end of the transverse stretching process until reaching the maximum temperature in the heat setting process is controlled to 1000 ° C./min or less,
The maximum reached surface temperature of the polyester film in the heat setting step is controlled to 130 ° C or higher and 230 ° C or lower, and the time during which the surface temperature of the polyester film exceeds 130 ° C is controlled to 180 seconds or shorter. The manufacturing method of the polyester film of description.   The polyester film according to any one of claims 13 to 15, further comprising a heat relaxation step of heating the polyester film after the heat setting step and shrinking at least a lateral length of the polyester film. Production method. The process of manufacturing a polyester film with the manufacturing method of the polyester film of any one of Claims 13-16,
Laminating a hard coat layer on at least one side of the polyester film;
The manufacturing method of the hard coat film which has this.