WO2014091987A1 - Laminated film and touch panel - Google Patents

Abstract

This laminated film comprises a polymer layer and a polyester film. Said polymer layer is at most 200 nm thick and comprises the following: a polyester that has a naphthalene skeleton; and grains having a mean diameter that is less than or equal to 0.65 times the thickness of the polymer layer. This laminated film satisfies relation (I) (in which n represents the index of refraction of the polymer layer and np represents the index of refraction of the polyester film), exhibits reduced interference irregularity, and has a good color. Relation (1) |n−np| ≤ 0.02

Description

Laminated film and touch panel

The present invention relates to a laminated film suitably used for a touch panel or the like and a touch panel using the laminated film.

Conventionally, a touch panel is often used for an electronic device equipped with a display device. Since the touch panel is provided on the surface layer of the electronic device, the touch panel is required to have scratch resistance, impact resistance, and the like. For this reason, the hard coat layer is used for the surface layer of the touch panel. Here, for the purpose of providing the hard coat layer smoothly, the hard coat layer is often laminated on a support such as a polyester film.

Generally, a functional layer such as a polyester film and a hard coat layer is composed of different components, so that it is difficult to directly bond the two. For this reason, the method of providing an easily bonding layer on a polyester film and laminating | stacking a hard-coat layer on it and making it a laminated film is known.

However, it is known that when a hard coat layer is provided, there is a problem that uneven interference is observed due to reflection at the interface.

For this problem, for example, in Patent Document 1, an optically easy-adhesive polyester film having a coating layer containing a polyester resin, particles A, and particles B on at least one surface of the polyester film, the polyester resin being an acid The particle A is a metal oxide particle having a refractive index of 1.7 or more and 3.0 or less, including naphthalenedicarboxylic acid as a component, a dicarboxylic acid component having a specific structure and / or a diol component having a specific structure. The particle B is a particle having an average particle size of 200 nm to 700 nm, and uses an easily adhesive polyester film for optics, and imparts antireflection properties to suppress reflection of external light, glare, iris color, and the like. It has been proposed to improve the adhesion with the hard coat layer and the adhesion after the high temperature and high humidity treatment.

Patent Document 2 uses a laminated polyester film characterized in that it has a coating layer containing a polyester resin containing a naphthalene skeleton, a metal oxide, and a urethane resin on at least one side of the polyester film, and reflects outside light. It has been proposed to reduce the unevenness of interference caused by the above and improve the adhesion to various surface functional layers such as a hard coat.

On the other hand, a polyester film for optical use is required to have a good color. For example, Patent Document 3 is a film made of polyester, and the film haze is in the range of 1.0 to 3.0%. In the single-sheet transmission color tone, the b value is in the range of 0.1 to 2.0, and the a value / b value is in the range of -1.0 to -0.1. An axially oriented polyester film is disclosed.

JP 2011-5854 A JP 2011-246663 A JP 2008-195803 A

On the other hand, regarding the touch panel that is often used in recent years, there is a problem that the bone structure of the ITO, in which the electrode structure is conspicuously observed due to the difference in refractive index between the ITO (Indium Tin Oxide) electrode used in the touch panel and the hard coat layer. In order to solve this problem, means for increasing the refractive index of the hard coat layer may be used.

When the present inventors examined, in the Example of patent document 2 with which the refractive index of a hard-coat layer was as low as the past, there was no problem of interference nonuniformity, but when the refractive index of a hard-coat layer was higher than before. It has been found that even if the technique of Patent Document 2 is used, the occurrence of interference unevenness cannot be sufficiently suppressed.

Moreover, although the technique of patent document 1 can suppress generation | occurrence | production of interference nonuniformity, on the other hand, since the unevenness | corrugation is made in the interface of a coating layer and a hard-coat layer, and light is scattered, the color of a film is bad. I knew it would be.

Further, although the color of the film is good in the technique of Patent Document 3, interference unevenness when the hard coat layer is laminated is not considered, and the invention of the Example of Patent Document 3 also adjusts the refractive index of the coating layer. Therefore, it has been found that the occurrence of uneven interference cannot be suppressed.

That is, when the refractive index of the hard coat layer is high, there is a problem that interference unevenness and color, which are important performances for optical applications, cannot be improved by the conventional technology.

The problem to be solved by the present invention is to provide a laminated film having a favorable color tone with suppressed occurrence of uneven interference.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that by making the configuration of the laminated film a specific condition, it is possible to achieve both suppression of interference unevenness and good color. .

Specifically, it has a polymer layer and a polyester film, the polymer layer has a polyester having a naphthalene skeleton and particles, the thickness of the polymer layer is 200 nm or less, and the average particle size of the particles is the polymer layer. The thickness is 0.65 times or less, and a laminated film satisfying the following formula (I) is used, while suppressing the occurrence of interference unevenness by substantially equalizing the refractive index of the polymer layer and the polyester film, By setting the thickness of the polymer layer to 200 nm or less and the average particle size of the particles of the polymer layer to 0.65 times or less of the thickness of the polymer layer, unevenness on the surface of the polymer layer is reduced and light is less likely to be scattered. Therefore, the present inventors have succeeded in obtaining a laminated film having a good color and have completed the present invention.
Formula (I) | n−np | ≦ 0.02
(In formula (I), n represents the refractive index of the polymer layer, and np represents the refractive index of the polyester film.)

Specifically, the present invention has the following configuration.

[1] It has a polymer layer and a polyester film,
The polymer layer has a polyester having a naphthalene skeleton and particles,
The polymer layer has a thickness of 200 nm or less,
The average particle diameter of the particles is 0.65 times or less the thickness of the polymer layer,
A laminated film satisfying the following formula (I).
Formula (I) | n−np | ≦ 0.02
(In formula (I), n represents the refractive index of the polymer layer, and np represents the refractive index of the polyester film.)
[2] In the laminated film according to [1], the refractive index of the particles is 1.60 or more and 3.00 or less.
[3] In the laminated film according to [1] or [2], the particles are preferably metal oxide particles.
[4] In the laminated film according to any one of [1] to [3], the polymer layer preferably has a refractive index of 1.63 to 1.69.
[5] In the laminated film according to any one of [1] to [4], the polyester film preferably has a refractive index of 1.62 to 1.71.
[6] In the laminated film according to any one of [1] to [5], the polyester having a naphthalene skeleton preferably has a refractive index of 1.60 or more and 1.75 or less.
[7] The laminated film according to any one of [1] to [6], wherein the laminated film is a laminated film for laminating a hard coat layer having a refractive index of 1.64 or more and 2.10 or less. Is preferred.
[8] The laminated film according to any one of [1] to [7] preferably has a hard coat layer having a refractive index of 1.64 or more and 2.10 or less.
[9] The laminated film according to [8] preferably includes the hard coat layer, the polymer layer, and the polyester film in this order.
[10] The laminated film according to [8] or [9] preferably has a b * value of 0.1 to 1.0 in the laminated film.
(Here, the b * value represents the b * value in the L * a * b * color system.)
[11] In the laminated film according to any one of [1] to [10], the thickness of the polymer layer is preferably 50 nm or more.
[12] In the laminated film according to any one of [1] to [11], the average particle diameter of the particles is preferably 5 nm to 130 nm.
[13] In the laminated film according to any one of [1] to [12], the particles are preferably tin oxide or zirconium oxide.
[14] In the laminated film according to any one of [1] to [13], the particles are preferably contained in an amount of 40% by mass or more and 80% by mass or less based on the solid content contained in the polymer layer. .
[15] In the laminated film according to any one of [1] to [14], the polyester having the naphthalene skeleton preferably has a number average molecular weight of 15000 or more and 40000 or less.
[16] The laminated film according to any one of [1] to [15], wherein the polyester having the naphthalene skeleton has a glass transition temperature of 80 to 130 ° C.
The polymer layer preferably further comprises a polyester having a glass transition temperature of 0 to 80 ° C.
[17] In the laminated film according to any one of [1] to [16], the polymer layer preferably further has a surfactant.
[18] In the laminated film according to any one of [1] to [17], the polymer layer preferably further has a crosslinking agent.
[19] In the laminated film according to any one of [1] to [18], the polymer layer preferably further has a colorant.

[20] A touch panel comprising the laminated film according to any one of [1] to [19] and a transparent conductive layer.

According to the present invention, it is possible to provide a laminated film having a good color tone with suppressed occurrence of interference unevenness.

FIG. 1 is a cross-sectional view showing an example of the laminated film of the present invention. FIG. 2 is a cross-sectional view showing an example of a laminated film having a hard coat layer of the present invention.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention 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, (meth) acrylate is used in the meaning containing both acrylate and methacrylate.
In the present invention, the refractive index represents a value at a wavelength of 660 nm.

[Laminated film]
As shown in FIG. 1, the laminated film 4 of the present invention includes a polyester film 1 and a polymer layer 2. The polymer layer 2 is preferably laminated adjacently on at least one surface of the polyester film 1. The polymer layer 2 includes a polyester (not shown) having a naphthalene skeleton and particles 3. Here, the thickness of the polymer layer 2 is 200 nm or less, and the average particle diameter of the particles 3 is 0.65 times or less of the thickness of the polymer layer 2.
Moreover, the laminated film 4 of the present invention satisfies the following formula (I).
Formula (I) | n−np | ≦ 0.02
In formula (I), n represents the refractive index of the polymer layer 2, and np represents the refractive index of the polyester film 1.

As shown in FIG. 2, when the laminated film 4 of the present invention has the hard coat layer 5, the laminated film 4 has the hard coat layer 5, the polymer layer 2, and the polyester film 1 in this order. Is preferred.

While suppressing the occurrence of interference unevenness by making the refractive index of the polymer layer and the polyester film substantially the same, the thickness of the polymer layer is 200 nm or less, and the average particle diameter of the particles of the polymer layer is 0 of the thickness of the polymer layer. By setting it to .65 times or less, irregularities on the surface of the polymer layer can be reduced, light can be hardly scattered, and a laminated film with good color can be obtained.

The interference unevenness in the present invention represents a rainbow-colored unevenness that looks like spots when the film is observed. Interference unevenness is particularly easy to see under a three-wavelength fluorescent lamp, which is often used in recent years. When interference unevenness occurs, the visibility is lowered when the laminated film is used for a touch panel or the like and is incorporated in a display device. Therefore, it is preferable to suppress the occurrence of interference unevenness as much as possible.

The color tone in the present invention represents that the film looks yellow when the film is observed. In the present invention, the color is represented by a b * value in the L * a * b * color system. The b * value is preferably from 0.1 to 1.0. By setting it as the said range, there is little coloring of the image observed when the laminated | multilayer film of this invention are utilized for a touch panel etc., and it incorporates in a display apparatus, and it can make visibility favorable.
The b * value is preferably from 0.1 to 0.9, and more preferably from 0.1 to 0.8.
The b * value in the present invention represents the b * value measured in the transmission mode using a spectrocolorimeter CM-3600d manufactured by Konica Minolta Sensing Co., Ltd. in the L * a * b * color system.

Hereinafter, members used for the laminated film of the present invention will be described in detail.

(Polyester film)
The laminated film of the present invention includes a polyester film. It is preferable that the polyester film used for this invention functions as a support body which supports the polymer layer mentioned later.

The refractive index np of the polyester film used in the present invention is preferably 1.62 or more and 1.71 or less, and more preferably 1.63 or more and 1.68 or less.
By setting it as the said range, the transparency of a polyester film can be made higher. In addition, the refractive index can be easily adjusted with respect to the other layers.

The thickness of the polyester film used in the present invention is preferably 30 to 400 μm, more preferably 50 to 250 μm. The polyester film used in the present invention may be a single-layer polyester film or a laminate of two or more polyester films (for example, a co-extruded film). When the polyester film used for this invention consists of two or more layers, it is preferable to make the total thickness into the said range.

The polyester film used in the present invention contains polyester as a main component. “Containing polyester as a main component” in the present invention means that 90% by mass or more of the resin component is polyester. It is preferable that 95 mass% or more of a resin component is polyester, and it is more preferable that 98 mass% or more is polyester. The kind in particular of polyester is not restrict | limited, A well-known thing can be used as polyester. Specific examples include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, and the like. Among these, polyethylene terephthalate (PET) is preferably used from the viewpoint of cost and mechanical strength.

The polyester film used in the present invention may contain other additives without departing from the spirit of the present invention. For example, an antioxidant or an ultraviolet ray inhibitor can be added as necessary.

The polyester film used in the present invention is preferably biaxially stretched. Biaxial stretching refers to stretching in both directions by regarding the width direction and the longitudinal direction of the film as uniaxial. Thus, the biaxially stretched polyester film has very good mechanical strength because the molecular orientation in the width direction and the longitudinal direction of the film is sufficiently controlled. The stretching ratio is not particularly limited, but the stretching ratio in one direction is preferably 1.5 to 7 times, more preferably 2 to 5 times, where the unstretched state is 1 time. By setting the draw ratio to 1.5 times or more, the mechanical strength can be increased, and by setting the draw ratio to 7 times or less, variations in film thickness can be easily suppressed. In particular, a polyester film biaxially stretched at a stretch ratio of 2 to 5 times in one direction has a very excellent mechanical strength because the molecular orientation is controlled more efficiently and effectively. It is suitable as a polyester film used in Moreover, the refractive index of a polyester film is controllable to the above-mentioned preferable range by carrying out biaxial stretching by the magnification | multiplying_factor of said range.

The polyester film used in the present invention may be subjected to a surface treatment. Examples of the surface treatment in this case include corona treatment, flame treatment, vacuum plasma treatment, atmospheric pressure plasma treatment, and glow discharge treatment. By performing the surface treatment of the polyester film, it is possible to improve the adhesion with the polymer layer described later.

(Polymer layer)
The laminated film of the present invention includes a polymer layer. The polymer layer used in the present invention preferably functions as an easy adhesion layer that facilitates adhesion of the polyester film and a functional layer such as a hard coat layer described later. The polymer layer used in the present invention is preferably formed on at least one surface of the polyester film.

The refractive index n of the polymer layer used in the present invention is | n−np | ≦ 0.02 with respect to the refractive index np of the polyester film described above. By setting the refractive index of the polymer layer used in the present invention within the above range, the occurrence of interference unevenness can be reduced.
Specifically, the refractive index n of the polymer layer used in the present invention is preferably from 1.63 to 1.69, more preferably from 1.63 to 1.66. By setting it as the said range, it can be made easy to adjust a refractive index with respect to another layer.

The thickness of the polymer layer used in the present invention is 200 nm or less. The thickness of the polymer layer used in the present invention is determined by required optical performance, easy adhesion, and the like. The thickness of the polymer layer used in the present invention is preferably 50 nm or more, and more preferably 80 nm or more. By setting the thickness of the polymer layer used in the present invention in the above range, it is possible to enhance the easy adhesion when the polymer layer functions as an easy adhesion layer. In addition, the thickness of the polymer layer used in the present invention is preferably 180 nm or less, and more preferably 150 nm or less. By setting the thickness of the polymer layer used in the present invention in the above range, the surface state of the polymer layer can be made to be in a better state, and interference unevenness can be suppressed.

<Polyester having naphthalene skeleton>
The polymer layer used in the present invention contains polyester having a naphthalene skeleton.
In the present invention, the polyester having a naphthalene skeleton represents that a monomer having a naphthalene skeleton is included as a monomer constituting the polyester. The monomer having a naphthalene skeleton is preferably contained as a dicarboxylic acid component, and examples thereof include 2,6-naphthalenedicarboxylic acid.

As a monomer constituting the polyester having a naphthalene skeleton used in the present invention, a monomer having no naphthalene skeleton can be included as necessary, such as adjustment of refractive index. In the monomer having no naphthalene skeleton used in the present invention, examples of the dicarboxylic acid component include terephthalic acid and isophthalic acid, and examples of the diol component include ethylene glycol and diethylene glycol.
When the monomer having a naphthalene skeleton used in the present invention is a dicarboxylic acid component, the structural unit derived from the monomer having a naphthalene skeleton is preferably from 50 mol% to 100 mol%, preferably from 60 mol% to 80 mol% in the dicarboxylic acid component. % Or less is more preferable.

The number average molecular weight of the polyester having a naphthalene skeleton used in the present invention is preferably 15000 to 40000, more preferably 17000 to 30000, and further preferably 18000 to 25000. By adjusting the number average molecular weight of the polyester having a naphthalene skeleton used in the present invention within the above range, the adhesion between the polymer layer and the polyester film, particularly the adhesion after wet heat aging can be enhanced.
In the present invention, the number average molecular weight represents the number average molecular weight measured by GPC (Gel Permeation Chromatography) as a standard material as polystyrene.

The refractive index of the polyester having a naphthalene skeleton used in the present invention is preferably 1.60 or more and 1.75 or less, and more preferably 1.60 or more and 1.70 or less. By adjusting the refractive index of the polymer layer within the above range, the amount of particles to be described later can be reduced, and adhesion when the polymer layer functions as an easy adhesion layer can be increased.

The content of the polyester having a naphthalene skeleton used in the present invention in the polymer layer is preferably 5% by mass or more and 80% by mass or less, and preferably 10% by mass or more and 60% by mass with respect to the total solid content in the polymer layer. The following is more preferable.

<Particle>
The polymer layer used in the present invention contains particles. The particles used in the present invention can easily adjust the refractive index of the polymer layer. There may be only one type of particles used in the present invention, or two or more types.

The refractive index of the particles used in the present invention is preferably 1.60 or more and 3.00 or less, more preferably 1.80 or more and 2.80 or less, and further preferably 1.90 or more and 2.60 or less. . By setting it as the above range, the refractive index of the polymer layer can be easily adjusted.

The average particle diameter of the particles used in the present invention is 0.65 times or less with respect to the thickness of the polymer layer. It is more preferably 0.50 times or less, and further preferably 0.40 times or less. By setting it as the said range, an unevenness | corrugation becomes difficult to be formed in the surface of a polymer layer, scattering of light can be reduced, and the color of a laminated | multilayer film can be made favorable. Although it does not specifically limit about a minimum, It is preferable that it is 0.05 times or more.
Specifically, the average particle size of the particles used in the present invention is preferably 5 nm or more and 130 nm or less. 5 nm or more and 100 nm or less are more preferable, and 5 nm or more and 80 nm or less are more preferable. By setting the thickness to 130 nm or less, the influence of light being scattered by the particles is reduced, and by setting the thickness to 5 nm or more, the particles are not aggregated and can hardly be made large.

The average particle size of the particles in the present invention was measured with a laser diffraction / scattering particle size distribution measuring apparatus LA910 (manufactured by Horiba, Ltd.) using an aqueous dispersion of particles, and expressed in median size.
In addition, after the production of the laminated film of the present invention, the average particle size of the particles contained in the polymer layer of the laminated film of the present invention is the same as that of the particles contained in the polymer layer after dissolving only the polymer layer in the solvent. It can measure using the said apparatus after preparing an aqueous dispersion.

The particles in the present invention are preferably contained in an amount of 40% by mass to 80% by mass with respect to the solid content of the polymer layer. It is preferably 45 to 75% by mass, and more preferably 50 to 70% by mass. By setting it as the said range, while making it easy to adjust the refractive index of a polymer layer, particle | grains do not overflow from a polymer layer, but it can make it difficult to form the unevenness | corrugation on the surface of a polymer layer.

Examples of the particles used in the present invention include conductive metal particles and metal oxide particles, and metal oxide particles are preferable.

Examples of the conductive metal particles include particles of antimony, selenium, titanium, tungsten, tin, zinc, indium and the like.

Examples of the metal oxide particles include particles containing any one of tin oxide, zirconium oxide and titanium oxide as a main component. Here, the particle containing any one of tin oxide, zirconium oxide and titanium oxide as the main component in the present invention means that the compounding amount of any one of tin oxide, zirconium oxide and titanium oxide contained in the particle is 80% by mass or more. A certain particle.
Among these, it is preferable to use tin oxide or zirconium oxide.

As the tin oxide, tin (IV) oxide having a SnO ₂ composition is preferably used. In the case of using tin oxide, the use of tin oxide doped with antimony or the like has the effect of reducing the surface resistivity of the laminated film and preventing impurities such as dust from adhering because of its conductivity. Since it is obtained, it is preferable. As such antimony-doped tin oxide, commercially available products can also be used. FS-10D, SN-38F, SN-88F, SN-100F, TDL-S, TDL-1 (all of which are Ishihara Sangyo) Etc.).
On the other hand, in order to prevent malfunction of the touch panel, inorganic oxide fine particles having no conductivity may be preferably used. For example, tin oxide prepared so as not to reduce the surface resistance without doping antimony or the like into tin oxide can be suitably used. Also, tin oxide doped with phosphorus (for example, manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd., EP SPDL-2, aqueous dispersion of P-doped SnO _{2 having} a particle size of 130 nm) and the like.
Among these, in the present invention, it is particularly preferable to use tin oxide not doped with antimony as tin oxide.

Zirconium oxide has a composition of ZrO ₂ such as NZS-20A, NZS-30A, OZ-S30K (all manufactured by Nissan Chemical Industries, Ltd.) and SZR-CW (manufactured by Sakai Chemical Industries, Ltd.). These are also suitable for the present invention.

As titanium oxide, titanium oxide (IV) having a composition of TiO ₂ is preferably used. Titanium oxide has a rutile type (tetragonal high-temperature type), anatase type (tetragonal low-temperature type), etc. depending on the difference in crystal structure, but is not particularly limited. Further, titanium oxide subjected to surface treatment may be used. Examples of the titanium oxide used in the present invention include IT-S, IT-O, IT-W (all manufactured by Idemitsu Kosan Co., Ltd.), TTO-W-5 (manufactured by Ishihara Sangyo Co., Ltd.), and the like. And can also be suitably used in the present invention.

The shape of the particles used in the present invention may be acicular or spherical, but is preferably spherical. In addition, even when the shape of the particles used in the present invention is not perfectly spherical, the average particle diameter of the particles can be measured by the above-described method. However, when the shape of the particles is not perfectly spherical, When it is difficult to measure by the measuring method, the diameter of a circle circumscribing such shaped particles can be determined as the particle diameter in the present invention.

<Other members>
The polymer layer used in the present invention may contain a member other than the members described above as necessary. An example will be described below.

<< second polyester >>
The polymer layer used in the present invention may further contain a second polyester in addition to the above-described polyester having a naphthalene skeleton.

When the polymer layer contains the second polyester, the glass transition temperature Tg ₁ of the polyester having a naphthalene skeleton is set to 80 to 130 ° C., and the glass transition temperature Tg ₂ of the second polyester is set to 0 to 80 ° C. It is also preferable.
The tg ₁ and tg ₂ within the above range, the polymer layer and the other layers, it is possible to achieve an enhancement in adhesion between the hard coat layer to be described later.
Tg ₁ is preferably 90 to 120 ° C., and more preferably 100 to 115 ° C. Tg ₂ is preferably 20 to 70 ° C., more preferably 30 to 60 ° C.

Tg ₁ -Tg ₂ is preferably 20 ° C. or higher, and more preferably 40 ° C. or higher. By setting Tg ₁ -Tg ₂ to be equal to or more than the above lower limit value, the adhesion can be more effectively improved.

In the present invention, the glass transition temperature represents a glass transition temperature measured by DSC (Differential Scanning Calibration) as follows.
Weigh 10 mg of polyester and set in an aluminum pan. At a rate of temperature increase of 10 ° C./min, the temperature is raised from room temperature to 300 ° C., rapidly cooled, and again heated at 10 ° C./min to obtain a DSC curve. The temperature at which the obtained DSC curve is bent is defined as the glass transition temperature.

The second polyester may contain one or more of terephthalic acid, isophthalic acid and sodium sulfoisophthalate as the acid component.

The second polyester resin may contain triethylene glycol as a diol component. Triethylene glycol can enhance the adhesion of the polymer layer formed using the second polyester.

The content of triethylene glycol is 10 to 50 mol% with respect to the total diol component of the second polyester resin. The content of triethylene glycol may be 10 to 50 mol%, preferably 15 to 45 mol%, and more preferably 20 to 40 mol%.

The number average molecular weight of the second polyester is preferably 15000 to 40000. The number average molecular weight of the second polyester is preferably 17000 to 30000, and more preferably 18000 to 25000. By setting the number average molecular weight of the second polyester within the above range, the adhesion between the polymer layer and the polyester film, particularly the adhesion after wet heat aging can be enhanced.

When the content of the polyester having a naphthalene skeleton contained in the polymer layer is P and the content of the second polyester is Q, it is preferable that P: Q = 20: 80 to 80:20, and 30: It is more preferably 70 to 70:30, and further preferably 40:60 to 60:40. By setting P: Q within the above range, good adhesiveness can be obtained.

<< Binder >>
The polymer layer used in the present invention may contain polyolefin, acrylic, polyurethane, rubber-based resin or the like as a binder in order to further improve the adhesion to the polyester film.

As content in the polymer layer of the binder used for this invention, 0.5 mass% or more and 40 mass% or less are preferable with respect to the total solid of a polymer layer, and 1.5 mass% or more and 30 mass% or less are more. preferable.

The polyolefin preferably has a polar group such as a carboxyl group as an ionomer of the polyolefin having a polar group. It may be used by dissolving in an organic solvent, or an aqueous dispersion may be used. However, since the environmental load is small, it is preferable to attach with an aqueous system using an aqueous dispersion. A commercially available product may be used as the aqueous dispersion and is not particularly limited. Examples of those that can be preferably used in the present invention include Chemipearl S75N (manufactured by Mitsui Chemicals), Arrow Base SE1200. Arrowbase SB1200 (above, manufactured by Unitika Ltd.), Hitech S3111, S3121 (above, produced by Toho Chemical Co., Ltd.), and the like. Only one type of polyolefin may be included, or two or more types may be included.

As the acrylic, acrylic containing methacrylate and ethyl acrylate and other copolymerization components is preferable, and those described in paragraphs [0145] to [0146] of JP2012-101449A can be used. Commercial products may also be used, and specific examples include AS-563A manufactured by Daicel Finechem Co., Ltd.
Acrylic has a glass transition temperature of preferably −50 to 120 ° C., and more preferably −30 to 100 ° C. The weight average molecular weight of acrylic is preferably 3000 to 1000000.

The polyurethane is preferably composed of polyol, polyisocyanate, chain extender, cross-linking agent, etc., and those described in paragraph [0035] of JP2012-056220A can be used.

<< Crosslinking agent >>
The polymer layer used in the present invention may contain a crosslinking agent. Examples of the crosslinking agent include epoxy-based, isocyanate-based, melamine-based, carbodiimide-based, and oxazoline-based crosslinking agents. Among these, a carbodiimide type crosslinking agent and an oxazoline type crosslinking agent are preferable.

As the carbodiimide-based crosslinking agent, a compound having a plurality of carbodiimide structures in the molecule is preferable. By including such a compound, the adhesiveness between the hard coat layer and the polymer layer tends to be improved when the hard coat layer is provided. A compound having a plurality of carbodiimide groups in the molecule can be used without particular limitation. Polycarbodiimide is usually synthesized by condensation reaction of organic diisocyanate, but the organic group of the organic diisocyanate used in this synthesis is not particularly limited, either aromatic or aliphatic, or a mixture thereof It can be used. From the viewpoint of reactivity, an aliphatic type is particularly preferable. As the synthetic raw material, organic isocyanate, organic diisocyanate, organic triisocyanate and the like are used. As examples of the organic isocyanate, those described in paragraph [0024] of JP2009-220316A can be used.
The carbodiimide-based crosslinking agent used in the present invention may be a commercially available product, and specific examples include Carbodilite V-02-L2 manufactured by Nisshinbo Co., Ltd.

As the oxazoline-based crosslinking agent, those described in paragraph [0078] of JP 2012-231029 A can be used. Commercial products may also be used, such as Epochros K2010E, K2020E, K2030E, WS500, WS500, and WS700 manufactured by Nippon Shokubai Chemical Industry Co., Ltd.

The crosslinking agent used in the present invention is preferably added in the range of 0.5 to 50% by mass, more preferably in the range of 1 to 30% by mass, based on the total amount of solids in the polymer layer. It is. By making the addition amount 1% by mass or more, the particles contained in the polymer layer can be effectively prevented from peeling off. On the other hand, when the addition amount is 50% by mass or less, the surface shape tends to be further improved. Two or more types of crosslinking agents may be included, and when two or more types are included, the total amount is preferably within the above range.

<< matting agent >>
The polymer layer used in the present invention may contain a matting agent for improving the slipperiness of the laminated film.
As the matting agent, either organic or inorganic fine particles can be used. For example, polymer fine particles such as polystyrene, polymethyl methacrylate, silicone resin, and benzoguanamine resin, and inorganic fine particles such as silica, calcium carbonate, magnesium oxide, and magnesium carbonate can be used. Among these, polystyrene, polymethyl methacrylate, and silica are preferable from the viewpoint of the effect of improving the slipperiness and cost.
These particles may be used alone or as a colloid dispersed in a dispersion medium such as water, such as colloidal silica. Examples of commercially available products include Snowtex XL (manufactured by Nissan Chemical Industries, Ltd.).
Two or more kinds of matting agents may be included.

The average particle size of the matting agent is preferably 0.03 to 1 μm, more preferably 0.05 to 0.5 μm. When the average particle size of the matting agent is 0.03 μm or more, the effect of improving the slip property is effectively exhibited, and when the average particle size is 1 μm or less, the laminated film is incorporated into a display device such as a touch panel. There is a tendency to suppress the deterioration of display quality.

In addition, the average particle size of the matting agent is preferably 0.65 times or less the thickness of the polymer layer, similarly to the average particle size of the particles of the polymer layer.
It is more preferably 0.50 times or less, and further preferably 0.40 times or less. By setting it as the said range, an unevenness | corrugation becomes difficult to be formed in the surface of a polymer layer, scattering of light can be reduced more, and the color tone of a laminated film can be made still more favorable.

In addition, the average particle diameter of the matting agent in the present invention is a value measured by the same method as the average particle diameter of the particles included in the polymer layer.

<< Surfactant >>
The polymer layer used in the present invention may have a surfactant to reduce repellency and the like when a functional layer such as a hard coat layer is applied to the surface of the polymer layer.
Examples of the surfactant include known anionic, nonionic, and cationic surfactants, and anionic and nonionic surfactants are preferably used. The surfactant is described, for example, in “Surfactant Handbook” (Ichirou Nishi, Ichiro Imai, Shozo Kasai edited by Sangyo Kasho, 1960).

Examples of commercially available anionic surfactants include Rapisol A-90, Rapisol A-80, Rapisol BW-30, Rapisol B-90, Rapisol C-70 (manufactured by NOF Corporation), NIKKOL OTP-100 ( Nikko Chemical Co., Ltd.), Koha Cool ON, Koha Cool L-40, Phosphanol 702 (Toho Chemical Industry Co., Ltd.), View Light A-5000, View Light SSS (Sanyo Chemical Industries Co., Ltd.), etc. Can be mentioned.

Examples of commercially available nonionic surfactants include, for example, NAROACTY CL-95 (manufactured by Sanyo Kasei Kogyo Co., Ltd.), Risolex Sakai BW400 (manufactured by Higher Alcohol Industry Co., Ltd.), EMALEX ET-2020 (manufactured by Nippon Emulsion Co., Ltd.). ), Unilube 50MB-26, Nonion IS-4 (manufactured by NOF Corporation), and the like.

<< Antistatic Agent >>
The polymer layer used in the present invention may have an antistatic agent in order to prevent the polymer layer from being charged by static electricity or the like.
The type of the antistatic agent is not particularly limited. For example, an electron conductive polymer such as polyaniline and polypyrrole, an ion conductive polymer having a carboxyl group or a sulfonic acid group in the molecular chain, conductive fine particles, etc. Is mentioned. Of these, the conductive tin oxide fine particles described in JP-A-61-20033 can be preferably used from the viewpoints of conductivity and transparency.

The addition amount of the antistatic agent is preferably added so that the surface resistivity of the polymer layer measured in an atmosphere of 25 ° C. and 30% relative humidity is 1 × 10 ⁵ Ω or more and 1 × 10 ¹³ Ω or less. When the surface resistivity is 1 × 10 ⁵ Ω or more, the addition amount of the antistatic agent can be kept low, and the transparency of the laminated film tends to be improved. By setting the surface resistivity to 1 × 10 ¹³ Ω or less, dust is removed. It tends to be more difficult to adhere.

<< Slipper >>
The polymer layer used in the present invention preferably contains an aliphatic wax as a slip agent in order to obtain the lubricity of the layer surface.

Specific examples of the aliphatic wax include plant waxes such as carnauba wax, candelilla wax, rice wax, wood wax, jojoba oil, palm wax, rosin-modified wax, olicuric wax, sugar cane wax, esparto wax, and bark wax. , Animal waxes such as beeswax, lanolin, whale wax, ibota wax, shellac wax, mineral waxes such as montan wax, ozokerite, ceresin wax, petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam, and fishertro push wax And synthetic hydrocarbon waxes such as polyethylene wax, oxidized polyethylene wax, polypropylene wax, and oxidized polypropylene wax. Among these, carnauba wax, paraffin wax, and polyethylene wax are particularly preferable because they are easy to adhere to a hard coat layer and a pressure-sensitive adhesive and have good lubricity. These are also preferably used as aqueous dispersions because they can reduce the environmental burden and are easy to handle. Examples of commercially available products include Cellosol 524 (manufactured by Chukyo Yushi Co., Ltd.).

<< Colorant >>
The polymer layer used in the present invention may have a colorant for adjusting the color tone of the polymer layer, particularly for reducing b *.
Examples of the colorant include dyes and pigments, preferably dyes. The colorant preferably has a wavelength of 380 to 570 nm, more preferably 380 to 485 nm, and particularly preferably 450 to 485 nm.
Specifically, organic blue pigments such as azo, triphenylmethane, quinoline, methyl, dioxazine, quinacridone, anthraquinone, phthalocyanine, organic blue dyes and inorganic blue pigments, inorganic blue dyes, etc. is there. Specific examples of the dye include Acid Blue 29, Oxamine Blue 4R, Cibacron Blue 3G-A, Direct Blue 1, Azophloxine, FP360, and the like.
The addition amount of the colorant is preferably 0.000001 wt% or more and 5 wt% or less, more preferably 0.00001 or more and 3 wt% or less, and particularly preferably 0.0001 or more and 0.5 wt% or less with respect to the solid content of the coating liquid for the polymer layer. preferable. If the amount of the colorant is large, b * is too low, the transmittance is further lowered, and it becomes unsuitable for a hard coat film and a touch panel using a laminated film.

<Manufacturing method>
The polymer layer used in the present invention is preferably formed by coating. Moreover, it is preferable to form on the surface of a polyester film. There is no restriction | limiting in particular as an application | coating method, Well-known methods, such as bar coater application | coating and slide coater application | coating, can be used.

When applying the polymer layer used in the present invention, a solvent (coating solvent) can be used. As the coating solvent, water, toluene, methyl alcohol, isopropyl alcohol, methyl ethyl ketone and the like, and aqueous and organic solvent based coating solvents such as a mixed system thereof can be used. Among these, the method using water as a coating solvent is preferable in view of cost and ease of production.

When the polymer layer used in the present invention is produced by coating, it is preferably cured by drying. Further, two or more polymer layers of the present invention may be laminated. In that case, it is preferable to dry and cure after applying the second and subsequent layers.

(Other layers)
In addition to the above-described members, the laminated film of the present invention may include other layers such as a release layer, a hard coat layer, an optical adjustment layer, a gas barrier layer, a transparent electrode layer such as an ITO electrode, a prism layer, and an antireflection layer. It may be provided. An example will be described below.

<Peeling layer>
A release layer may be further formed on the surface of the polymer layer of the laminated film of the present invention. Since the polymer layer has adhesiveness, if it is exposed, it may stick to an unintended article or the polymer layer itself may deteriorate. For this reason, in order to physically and chemically protect the polymer layer, a release layer is provided on the surface of the polymer layer, and when the other member is laminated on the polymer layer, the release layer is peeled off to remove the polymer layer. Other members can be laminated after being exposed.

Examples of the release layer include those in which a release agent layer such as silicone is applied to various plastic films to form a release agent layer, and a polypropylene film alone, which is used as a release sheet for ordinary pressure-sensitive adhesive sheets Can be used.

<Hard coat layer>
The laminated film of the present invention may have a hard coat layer. In that case, the polyester film and the polymer layer described above preferably function as a support for supporting the hard coat layer. When the laminated film of the present invention has a hard coat layer, the hard coat layer, the polymer layer, and the polyester film are preferably laminated in this order.
Moreover, the structure which the polymer layer mentioned above is arrange | positioned on the surface of a polyester film, and the hard-coat layer is arrange | positioned on the surface opposite to the polyester film of a polymer layer is also preferable. The hard coat layer is preferably adjacent to the polymer layer described above from the viewpoint of reducing the occurrence of interference unevenness.

The refractive index of the hard coat layer used in the present invention is preferably from 1.64 to 2.10, more preferably from 1.65 to 2.00, and even more preferably from 1.66 to 1.80. The refractive index n _HC of the hard coat layer preferably satisfies | n _HC− n | ≦ 0.05, where n is the refractive index of the polymer layer.
By setting the refractive index of the hard coat layer to the above range, interference unevenness can be reduced when used for the laminated film touch panel of the present invention.

The thickness of the hard coat layer used in the present invention is not particularly limited. It can be appropriately adjusted according to various physical properties such as required pencil hardness.

The hard coat layer used in the present invention is preferably mainly composed of a curable resin having high chemical resistance and scratch resistance. Examples of such a curable resin include an ionizing radiation curable resin, a thermosetting resin, and a thermoplastic resin. Among these, it is preferable to use an ionizing radiation curable resin that can easily form a layer and easily increase the pencil hardness to a desired value with respect to the laminated film.

As the ionizing radiation curable resin used for forming the hard coat layer used in the present invention described above, those described in paragraphs [0041] to [0048] of JP-A No. 2004-98324 can be preferably used.

Moreover, a commercially available ultraviolet curable resin can also be used, and specific examples include Z7410B manufactured by JSR Corporation.

The hard coat layer used in the present invention may contain an ultraviolet absorber. Thereby, ultraviolet degradation of a laminated film can be prevented and visibility can be maintained for a long time. The kind of ultraviolet absorber is not specifically limited, Various well-known things can be utilized. The addition amount of the ultraviolet absorber is preferably 0.1 to 10% by mass with respect to the resin forming the hard coat layer. By setting the content to 0.1% by mass or more, the effect of preventing ultraviolet light deterioration is sufficiently exhibited, and by setting the content to 10% by mass or less, it is possible to more effectively suppress a decrease in wear resistance and scratch resistance. As a method of adding the ultraviolet absorber, a method of adding it by dispersing in a solvent is preferable.

The hard coat layer used in the present invention may have particles for the purpose of adjusting the refractive index of the hard coat layer to the above preferred range. Examples of the particles are the same as the particles included in the polymer layer. Among them, it is preferable to use zirconium oxide particles from the viewpoint of adjusting the refractive index within the above preferable range.

The hard coat layer used in the present invention is preferably formed by coating. Moreover, it is preferable to form on the surface of the polymer layer used for the present invention described above. There is no restriction | limiting in particular as an application | coating method, Well-known methods, such as bar coater application | coating and slide coater application | coating, can be used. In this case, the solid concentration of the coating solution is preferably 30 to 70% by mass, more preferably 40 to 60% by mass.

The hard coat layer used in the present invention is preferably cured after being laminated in a layer form. As a curing method, a curing method according to the material of the hard coat layer can be employed. For example, an ionizing radiation curable resin can be cured by irradiation with ionizing radiation.

<Optical adjustment layer>
The laminated film of the present invention may have an optical adjustment layer for adjusting the difference in refractive index from the transparent electrode layer when used in a touch panel or the like.
When the laminated film of the present invention has a hard coat layer, the optical adjustment layer is preferably laminated adjacent to the surface of the hard coat layer.
By providing the optical adjustment layer, the difference in refractive index with the transparent electrode layer can be adjusted, and the aforementioned ITO bone appearance can be reduced.
As a manufacturing method of the optical adjustment layer, any film forming method can be used as long as the film thickness can be controlled. For example, a method described in JP 2012-206307 A can be used.

[Touch panel]
The touch panel of the present invention includes the above-described laminated film of the present invention and a transparent electrode layer.
As a transparent electrode layer that can be used for the touch panel of the present invention, any one of indium oxide, zinc oxide, tin oxide, or two or three mixed oxides thereof, and other additives are added. Although various materials can be used depending on the purpose and application, it is not particularly limited. At present, the most reliable and proven material is indium tin oxide (ITO).
As a method for producing the transparent electrode layer, any film forming method can be used as long as the film thickness can be controlled. For example, a method described in JP 2012-206307 A can be used.

The touch panel of the present invention can be used as an input device by being incorporated in a display device such as a liquid crystal display, a plasma display, an organic EL display, a CRT display, and electronic paper. By using the touch panel of the present invention, occurrence of interference unevenness can be suppressed and a touch panel with good color can be obtained.
There are two types of touch panel configurations, such as a resistance film type and a capacitance type. Capacitance type input devices have the advantage of simply forming a light-transmitting conductive film on a single substrate. A capacitance type is preferred. In such a capacitance-type input device, for example, when the electrode pattern is extended in a direction intersecting each other as the transparent electrode layer and a finger or the like comes into contact, it is detected that the capacitance between the electrodes changes. Thus, a type that detects the input position can be preferably used. Regarding the configuration of such a touch panel, for example, descriptions in JP 2010-86684 A, JP 2010-152809 A, JP 2010-257492 A, and the like can be referred to.
Regarding the configuration of an image display device equipped with a touch panel as a component, “Latest Touch Panel Technology” (published July 6, 2009, Techno Times), supervised by Yuji Mitani, “Technology and Development of Touch Panels”, CM Publishing (2004, 12), FPD International 2009 Forum T-11 Lecture Textbook, Cypress Semiconductor Corporation Application Note AN2292, and the like can be applied.
In addition, regarding the configuration of a liquid crystal display in which a touch panel can be incorporated, description in JP-A-2002-48913 can be referred to.

Hereinafter, the features of the present invention 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 invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

(Synthesis of polyester)
<Synthesis of Polyester X-1>
As an acidic component, 64 mol% of 2,6-naphthalenedicarboxylic acid, 14 mol% of terephthalic acid, 22 mol% of sodium 5-sulfoisophthalate, 73 mol% of ethylene glycol, 27 mol% of diethylene glycol as a diol component, acetic acid as a catalyst Zinc and antimony trioxide were charged into a reaction vessel, and an esterification reaction was performed at 220 ° C. for 3 hours. Subsequently, a polycondensation reaction was carried out at 250 ° C. under reduced pressure of 0.1 mHg for 3 hours to synthesize polyester X-1. X-1 had a glass transition temperature of 110 ° C., a number average molecular weight of 24,000, and a refractive index of 1.63.

<Synthesis of Polyester X-2>
The acid content was changed to 70 mol% for terephthalic acid, 17 mol% for isophthalic acid, 13 mol% for sodium 5-sulfoisophthalate, and 84 mol% for ethylene glycol and 16 mol% for diethylene glycol. Polyester X-2 was synthesized by the same method as -1. X-2 had a glass transition temperature of 69 ° C., a number average molecular weight of 23,000, and a refractive index of 1.57.

<Synthesis of Polyester Y-1>
As acidic components, terephthalic acid is 70 mol%, isophthalic acid is 25 mol%, sodium 5-sulfoisophthalate is 5 mol%, diol component is ethylene glycol 40 mol%, diethylene glycol 30 mol%, triethylene glycol 30%. Polyester Y-1 was synthesized in the same manner as X-1, except that the changes were made. Y-1 had a glass transition temperature of 45 ° C., a number average molecular weight of 20000, and a refractive index of 1.56.

Table 1 shows the composition, glass transition temperature, number average molecular weight, and refractive index of each polyester synthesized above.

(Example 1)
<Preparation of polyester film>
Polyethylene terephthalate (hereinafter referred to as PET) having an intrinsic viscosity of 0.66 polycondensed using antimony trioxide as a catalyst is dried to a moisture content of 50 ppm or less, and then melted in an extruder set at a heater temperature of 280 to 300 ° C. I let you. Next, the melted PET resin was discharged from a die part onto a chill roll electrostatically applied to obtain an amorphous film. Subsequently, the amorphous film was stretched 2.9 times with respect to the longitudinal direction of the film and then stretched 4.0 times with respect to the width direction of the film. A polyester film was prepared. The produced polyester film had a refractive index np of 1.66.

<Preparation of laminated film 1>
One surface of the produced polyester film was subjected to glow discharge treatment. The polymer layer coating solution was applied onto the glow discharge treated surface of the polyester film with a bar coater so as to achieve the dry film coating amount shown in Table 2, and dried at 165 ° C. for 2 minutes to obtain a polymer layer.
The thickness of the polymer layer was 130 nm, the refractive index was 1.65, and the value of the average particle diameter of the particles / the thickness of the polymer layer was 0.46.

(Examples 2 to 4 and Comparative Examples 1 to 3)
In the production of the laminated film 1, the laminated films 2 to 4 of Examples 2 to 4 and Comparative Examples 1 to 3 were prepared in the same manner as the production of the laminated film 1 except that the polymer layer was changed to the composition shown in Table 2 below. 7 was produced.

Table 2 below shows the composition, thickness, refractive index, average particle diameter of the particle / thickness of the polymer layer of the polymer layers of the laminated films 1 to 7 of the above examples and comparative examples.
In Table 2 below, tin oxide particles having an average particle diameter of 130 nm represent EP SPDL-2 manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.

<Preparation of laminated film having hard coat layer>
A hard coat layer coating solution having the following composition was formed by a bar coat method so that a wet thickness was formed so that the hard coat layer was formed adjacent to the surface of the polymer layers of the laminated films 1 to 7 of the above examples and comparative examples. It apply | coated so that it might become 2 micrometers. After drying at 90 ° C. for 1 minute, the resin was cured by irradiating ultraviolet rays at a dose of 1600 mJ / cm ² using a high-pressure mercury lamp. Thus, a hard coat layer was produced on the surface of the polymer layer, and laminated films 101 to 107 having the hard coat layer were produced. The hard coat layer had a thickness of 1 μm and a refractive index of 1.64.

・ 100 parts by mass of UV curable resin (manufactured by JSR Corporation, Z7410B)
・ Inorganic fine particles 20 parts by mass (zirconium oxide, manufactured by Nissan Chemical Industries, Ltd., OZ-S30K)

Table 3 below shows the results of evaluating the degree of interference unevenness, color, initial adhesion, and adhesion after wet heat aging of the laminated films of the above Examples and Comparative Examples.
The evaluation conditions for each evaluation item are shown below.

(Evaluation of interference unevenness of laminated film)
The laminated film 101 to 107 having the hard coat layer is generated by irradiating the hard coat layer side of the laminated film with the diffused light of the three-wavelength fluorescent lamp through the milky white acrylic plate from the desk on which the black doskin cloth is laminated. The reflected light was observed visually. And by visually observing the rainbow-colored interference unevenness observed at this time, ranking was performed according to the following evaluation criteria, and the interference unevenness of the laminated film was evaluated. Moreover, in visual observation, the blackening process was performed with respect to each film as forced condition evaluation, and what adjusted the transmittance | permeability of 500 nm light so that it might become 1% or less was evaluated separately. As the blackening treatment, magic ink (artline oil-based marker supplement ink KR-20 black, shachihata Co., Ltd.) was applied to the surface of the sample opposite to the surface to be observed (the surface opposite to the hard coat layer of the laminated film). After coating, the product was dried.
A: Iridescent interference unevenness is not visually confirmed in both the sample after the blackening treatment and the untreated sample.
C: Iridescent interference unevenness is visually confirmed in both the blackened sample and the untreated sample.

(Evaluation of color of laminated film)
For the laminated films 101 to 107 having a hard coat layer, b * values were measured in a transmission mode using a spectrocolorimeter (CM-3600d manufactured by Konica Minolta Sensing Co., Ltd.). The b * value represents the b * value in the L * a * b * color system, and the larger the value, the more yellow the transmitted light of the film.

(Evaluation of initial adhesion of laminated film)
One hundred blades were formed on the surfaces of the laminated films 101 to 107 having a hard coat layer by using 11 single-edged razors to make 11 scratches at 1 mm intervals in the vertical and horizontal directions. Next, cellophane tape (trade name: No. 405 manufactured by Nichiban Co., Ltd., No. 405, 24 mm width) was attached on this, and then completely adhered by rubbing with poppy rubber from above, and then the tape was applied to the hard coat layer at 90 ° C. The adhesion between the polymer layer of the laminated film and the hard coat layer was evaluated by obtaining the number of peeled cells by peeling the film by pulling it instantaneously in the direction.

(Evaluation of adhesion of laminated film after wet heat)
The laminated films 101 to 107 having the hard coat layer were held for 500 hours under the environmental conditions of 80 ° C. relative humidity 10% and 65 ° C. relative humidity 95%, and then conditioned for 1 hour under the environment of 25 ° C. relative humidity 60%. Then, the adhesiveness after wet heat aging between the polymer layer of the laminated film and the hard coat layer was evaluated by the same method as the evaluation of the initial adhesiveness of the laminated film described above. The evaluation method was also the same as the initial adhesion of the laminated film described above.

When the laminated film 101 using the laminated film 1 of Example 1 and the laminated film 104 using the laminated film 4 of Comparative Example 1 are compared, the average particle diameter of the particles of the polymer layer with respect to the thickness of the polymer layer is the laminated film. 101 is 0.46, which is 0.65 times or less, whereas the laminated film 104 has a value of 0.99 which exceeds 0.65 times, indicating that the laminated film 101 has a better color.
On the other hand, when the laminated film 101 and the laminated film 106 using the laminated film 6 of Comparative Example 3 are compared, the average particle diameter of the particles of the polymer layer does not change, but the thickness of the polymer layer is different. It can be seen that the laminated film 101 has a better color by changing the average particle diameter of the particles of the polymer layer with respect to the thickness of the film.
From this, it was found that the average particle diameter of the polymer layer / the thickness of the polymer layer is more important for the color than the average particle diameter of the particle of the polymer layer itself. .

When the laminated film 101 using the laminated film 1 of Example 1 and the laminated film 105 using the laminated film 5 of Comparative Example 2 are compared, the polyester that the polymer layer has has a naphthalene skeleton in the laminated film 101. On the other hand, the laminated film 105 does not have a naphthalene skeleton, and | n−np | ≦ 0.02 is satisfied in the laminated film 101 but not in the laminated film 105, and the laminated film 101 is more likely to cause interference unevenness. It can be seen that it has been reduced.

(Examples 5 to 8)
Separately, Acid Blue 29, Oxamine Blue 4R, Direct Blue 1, Azophloxine, and 0.005 mg / m ² in the polymer layer coating solution are added to the polymer layer coating solution of the laminated film 1 of Example 1 as a dye. Otherwise, the laminated films 8 to 11 of Examples 5 to 8 were produced in the same manner as the laminated film 1.
Further, using the laminated films 8 to 11, laminated films 108 to 111 having a hard coat layer were produced in the same manner as the laminated film 101 having a hard coat layer. When the laminated films 108 to 111 were evaluated, the interference unevenness, initial adhesion, and adhesion after wet heat aging were the same evaluation results as in Example 1, and the b * value was 0.2 to 0.6 for the color. And better results.

[Examples 11 to 18: Production of touch panel]
ITO was formed on the laminated film with a hard coat layer obtained in Examples 1 to 8 by a sputtering method so as to have a thickness of 20 nm. A stripe electrode was produced by photolithography to produce a touch panel. The touch panel produced in this example was excellent in interference unevenness and color.

According to the present invention, it is possible to provide a laminated film having a good color tone with suppressed occurrence of interference unevenness. For this reason, the laminated | multilayer film of this invention are used especially suitably for a touchscreen, and industrial applicability is high.

1 Polyester film 2 Polymer layer 3 Particles 4 Laminated film 5 Hard coat layer

Claims (20)

Having a polymer layer and a polyester film;
The polymer layer has a polyester having a naphthalene skeleton and particles,
The polymer layer has a thickness of 200 nm or less,
The average particle diameter of the particles is 0.65 times or less the thickness of the polymer layer,
A laminated film satisfying the following formula (I).
Formula (I) | n−np | ≦ 0.02
(In formula (I), n represents the refractive index of the polymer layer, and np represents the refractive index of the polyester film.) The laminated film according to claim 1, wherein the refractive index of the particles is 1.60 or more and 3.00 or less. The laminated film according to claim 1 or 2, wherein the particles are metal oxide particles. The laminated film according to any one of claims 1 to 3, wherein the polymer layer has a refractive index of 1.63 to 1.69. The laminated film according to any one of claims 1 to 4, wherein the refractive index of the polyester film is 1.62 or more and 1.71 or less. The laminated film according to any one of claims 1 to 5, wherein the polyester having the naphthalene skeleton has a refractive index of 1.60 or more and 1.75 or less. The laminated film according to any one of claims 1 to 6, wherein the laminated film is a laminated film for laminating a hard coat layer having a refractive index of 1.64 or more and 2.10 or less. The laminated film according to any one of claims 1 to 7, which has a hard coat layer having a refractive index of 1.64 or more and 2.10 or less. The laminated film according to claim 8, comprising the hard coat layer, the polymer layer, and the polyester film in this order. The laminated film according to claim 8 or 9, wherein the laminated film has a b * value of 0.1 or more and 1.0 or less.
(Here, the b * value represents the b * value in the L * a * b * color system.) The laminated film according to any one of claims 1 to 10, wherein the polymer layer has a thickness of 50 nm or more. The laminated film according to any one of claims 1 to 11, wherein an average particle diameter of the particles is 5 nm or more and 130 nm or less. The laminated film according to any one of claims 1 to 12, wherein the particles are tin oxide or zirconium oxide. The laminated film according to any one of claims 1 to 13, wherein the particles are contained in an amount of 40% by mass to 80% by mass with respect to the solid content contained in the polymer layer. The laminated film according to any one of claims 1 to 14, wherein the polyester having the naphthalene skeleton has a number average molecular weight of 15000 or more and 40000 or less. The polyester having the naphthalene skeleton has a glass transition temperature of 80 to 130 ° C.,
The laminated film according to any one of claims 1 to 15, wherein the polymer layer further comprises a polyester having a glass transition temperature of 0 to 80 ° C. The laminated film according to any one of claims 1 to 16, wherein the polymer layer further comprises a surfactant. The laminated film according to any one of claims 1 to 17, wherein the polymer layer further has a crosslinking agent. The laminated film according to any one of claims 1 to 18, wherein the polymer layer further has a colorant. A touch panel comprising the laminated film according to any one of claims 1 to 19 and a transparent conductive layer.

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