WO2014064999A1

WO2014064999A1 - Display device with touch panel

Info

Publication number: WO2014064999A1
Application number: PCT/JP2013/073134
Authority: WO
Inventors: 啓史別宮; 梅田　博紀
Original assignee: コニカミノルタ株式会社
Priority date: 2012-10-22
Filing date: 2013-08-29
Publication date: 2014-05-01
Also published as: KR101662466B1; KR20150056823A; JP5958550B2; JPWO2014064999A1

Abstract

A display device with a touch panel, wherein an electrode layer in the touch panel (20) is configured by one layer, and a conductive film (24) is pasted upon the electrode layer. The conductive film (24) has: a shatterproof film (25) comprising a cellulose ester film; and a conductive layer (26) formed by aqueous coating of a conductive material. In a polarizing plate (2) in the display device (10), a film (5) on the display panel (1) side relative to a polarizer (3) is an optical film having a moisture permeability of no more than 200 g/m²/24 h. The film (4) on the touch panel side relative to the polarizer (3) includes a cellulose ester film having a plasticizer and a thickness of 15-30 µm. The plasticizer is UV-bonded to the polarizer (3) via a surface on the opposite side to the side on which the plasticizer has a large amount of uneven distribution in the film thickness direction.

Description

Display device with touch panel

The present invention relates to a display measure with a touch panel in which a touch panel and a display device are bonded via an adhesive layer.

In recent years, as various electronic devices such as mobile phones, mobile terminals, and personal computers have become highly functional and diversified, touch panels are used as one of means for inputting to these electronic devices. The touch panel has optical transparency, and when it is bonded to a liquid crystal display device, for example, it is attached to the polarizing plate side of the liquid crystal panel via an adhesive.

Conventionally, a touch panel mounted on the surface of an information display unit of a mobile terminal is light-transmitting from the viewpoint of making the information displayed on the information display unit easy to see and not breaking even if the mobile terminal is dropped. A high-quality plastic plate was used. However, if the plastic plate is made thin in order to pursue the reduction in thickness and weight required for the portable terminal, the strength of the plastic plate is insufficient. In order to solve this problem, in recent years, a glass substrate having higher strength than a plastic plate has been used for a touch panel mounted on the surface of an information display unit.

However, when a glass substrate is used, the glass substrate may be damaged when the mobile terminal is dropped, and the fragments may be scattered. For this reason, it has been conventionally studied to use a glass scattering prevention film by bonding it to the surface of a glass substrate. Generally, a polyethylene terephthalate (PET) film that is inexpensive and has an anti-scattering effect is used as a glass anti-scattering film. Since the PET film generally has low adhesion to the pressure-sensitive adhesive layer, in order to improve the adhesion, a PET film with an easy adhesion layer provided with a thin film called an easy adhesion layer is used.

However, the PET film may generate interference fringes due to the refractive index relationship and may reduce the visibility of display information. In order to improve this, a triacetyl cellulose film with an adhesive layer is used instead of a PET film, and it is studied to prevent scattering of the glass substrate by bonding to the outermost surface of the glass substrate as a protective film. (For example, refer to Patent Document 1).

On the other hand, there are various types of touch panels, one of which is a capacitive touch panel. In this capacitive touch panel, an X electrode pattern formed on a transparent substrate so as to extend in the X direction by a transparent conductive film, and Y formed so as to extend in the Y direction by another transparent conductive film. An electrode pattern is provided. Examples of the X electrode pattern and the Y electrode pattern include a rectangular pattern and a diamond pattern, which are formed using ITO (Indium Tin Oxide). When the surface of the substrate of the touch panel is pressed with a finger, the X electrode pattern and the Y electrode pattern come into contact with each other, and the capacitance at that position changes. It is possible to specify the pressed position by detecting via the.

In a capacitive touch panel having such a two-layer transparent conductive film and a touch surface made of glass, a transparent optical double-sided tape (OCA; Optical) is applied to the two-layer transparent conductive film. If another glass substrate is pasted together through (Clear Adhesive tape) or a filler, the touch panel becomes thicker. In this regard, the electrostatic capacitance type touch panel of Patent Document 2 includes a two-layer transparent conductive film extending in directions orthogonal to each other and the touch surface is a glass substrate. By using only one glass substrate, the entire touch panel is reduced in thickness.

However, when a thin touch panel using only one glass substrate as in Patent Document 2 is attached to, for example, a liquid crystal display device as a display device via an adhesive layer, an electrode layer (X electrode pattern, The position of the (Y electrode pattern) approaches the liquid crystal panel. For this reason, when each pixel of the liquid crystal panel is driven, it is easily affected by electrical noise (including leakage current) generated by ON / OFF of a switching element (for example, TFT) provided corresponding to each pixel. Is likely to malfunction (for example, the pressed position cannot be detected accurately due to the noise).

Also, in the configuration in which two electrode layers are formed on the glass substrate, if either one of the two electrode layers is disconnected when the glass substrate is cut, a defective product is obtained. For this reason, the probability of becoming a defective product is high, leading to a decrease in yield and a decrease in productivity of the touch panel.

In contrast, the touch panel of Patent Document 3 employs a configuration in which only one electrode layer on the substrate is provided, and a shield layer is provided on the opposite side of the substrate from the electrode layer. By making the electrode layer one layer, it is possible to avoid a decrease in yield due to the disconnection of the electrode layer when cutting the glass substrate, and it is possible to cut off electrical noise from the display panel with a shield layer, thereby suppressing malfunction of the touch panel. It is considered possible.

JP 2011-209512 A (refer to claim 1, paragraph [0012], FIG. 1, etc.) JP 2011-186717 A (refer to claim 1, paragraphs [0016] and 0022], FIG. 1 and the like) Japanese Patent Laying-Open No. 2012-008255 (see paragraph [0107], FIG. 4 etc.)

By the way, the polarizing plate of the liquid crystal display device to which the touch panel is bonded has a structure in which a polarizer is sandwiched between a surface protective film (film on the touch panel side) and a back surface protective film (film on the display panel side). At this time, as a method of bonding the surface protective film and the back surface protective film to the polarizer, there is a method of bonding by ultraviolet irradiation (UV irradiation). In this method, an ultraviolet curable adhesive is applied to the front and back surfaces of the polarizer, the UV light is irradiated to the adhesive in a state where the polarizer is sandwiched between the front and back protective films, and the adhesive is cured. By doing so, a polarizing plate is formed. However, when UV irradiation is performed, the orientation of the polarizer is disturbed due to curing shrinkage of the adhesive during UV irradiation, and the contrast is lowered.

Also, for example, when the above-described shield layer is bonded to a film by aqueous coating, or when the polarizer is formed of a PVA (polyvinyl alcohol) film, moisture is contained in the shield layer or the polarizer. At this time, if the moisture permeability of the back surface protective film of the polarizer is high, the moisture is absorbed by the back surface protective film, and the retardation (retardation) of the back surface protective film varies. Since the back surface protective film is positioned on the display panel side with respect to the polarizer, if the phase difference of the back surface protective film fluctuates, display unevenness such as white spots occurs during black display.

Furthermore, if the glass substrate is located in the outermost layer of the touch panel (the layer opposite to the display device), the moisture cannot pass through the glass substrate and cannot escape to the outside of the touch panel. Then, the polarizer may be deteriorated by the moisture, resulting in a reddish display during black display.

In view of the circumstances described above, an object of the present invention is to suppress a decrease in the yield of touch panels and malfunction due to electrical noise, and to adhere a protective film to both sides of a polarizer via an ultraviolet curable adhesive. An object of the present invention is to provide a display device with a touch panel that can suppress disorder of the orientation of the polarizer due to curing shrinkage of the agent, fluctuation of the retardation of the back surface protective film, and deterioration of the polarizer due to moisture.

The above object of the present invention is achieved by the following configuration.

1. A display device with a touch panel in which the electrode layer side of a touch panel having an electrode layer on a glass substrate and the polarizing plate side of a display device having a polarizing plate on a display panel are bonded via an adhesive layer. ,
The electrode layer of the touch panel is composed of one layer, and a conductive film is bonded on the electrode layer,
The conductive film is made of a cellulose ester film and is formed by a water-based coating of a conductive material on the side opposite to the electrode layer with respect to the scattering prevention film for preventing the glass substrate from scattering. And a conductive layer
The polarizing plate includes a polarizer, a surface protective film bonded to the touch panel side of the polarizer via an ultraviolet curable adhesive, and an ultraviolet curable adhesive on the display panel side of the polarizer. With a back surface protective film bonded through
The back surface protective film is a following optical film moisture permeability 200g ^/ m 2 ^/ 24h,
The surface protective film is a cellulose ester film having a plasticizer and having a thickness of 15 to 30 μm, and the polarizing film passes through a surface opposite to the side where the plasticizer is unevenly distributed in the thickness direction of the film. A display device with a touch panel, which is bonded to a child.

2. 2. The display device with a touch panel as described in 1 above, wherein the polarizing plate further has a hard coat layer on the side opposite to the polarizer with respect to the surface protective film.

3. The display device with a touch panel according to 1 or 2, wherein the conductive material is a conductive fiber.

4. 4. The display device with a touch panel as described in 3 above, wherein the conductive fiber is a metal nanowire.

5. 5. The display device with a touch panel according to any one of 1 to 4, wherein the optical film of the back surface protective film is a film made of any one of acrylic, cyclic polyolefin, and polycarbonate.

According to said structure, since the electrode layer on a glass substrate is one layer in a touch panel, the fall of the yield by the disconnection of the electrode layer at the time of cutting a glass substrate, and the fall of productivity of a touch panel can be suppressed. . Further, scattering of the glass substrate due to impact or the like can be prevented by the anti-scattering film, and further, electrical noise from the display device can be blocked by the conductive layer, and malfunction of the touch panel can be suppressed.

Further, in the configuration in which the surface protective film is bonded to the polarizer via an ultraviolet curable adhesive, the surface protective film is a surface opposite to the side where a large amount of plasticizer is unevenly distributed in the thickness direction of the cellulose ester film. Since the adhesive is bonded to the polarizer through the adhesive, it suppresses the curing shrinkage of the adhesive due to ultraviolet irradiation, and a lot of plasticizer is arranged on the surface on the touch panel side, so that the stress when the touch panel is pressed is reduced. It can be absorbed by a cellulose ester film. As a result, it is possible to suppress the disorder of the orientation of the polarizer and to suppress the decrease in contrast.

Further, the back surface protective film of a polarizing plate includes the following optical film moisture permeability 200g ^/ m 2 ^/ 24h. Thereby, it is possible to suppress the moisture content of the conductive layer formed by aqueous coating and the moisture content of the polarizer (for example, PVA) from being transmitted, and to prevent the retardation (retardation) of the back protective film from fluctuating due to the moisture content. It is possible to suppress the occurrence of display irregularities such as white spots during black display.

Moreover, since both the scattering prevention film and the surface protective film of the polarizing plate contain a cellulose ester film having high moisture absorption and moisture permeability, the moisture can be trapped (captured) by both cellulose ester films. . Thereby, it can suppress that a polarizer deteriorates with the said water | moisture content, and it can suppress that it becomes a reddish display at the time of black display.

In addition, since the cellulose ester film of the surface protective film is as thin as 15 to 30 μm, it is easy for water to escape from the polarizer to the anti-scattering film via the surface protective film, and the deterioration of the polarizer due to moisture is ensured. Can be suppressed.

It is sectional drawing which shows the schematic structure of the display apparatus with a touchscreen which concerns on embodiment of this invention.

An embodiment of the present invention will be described below with reference to the drawings. In this specification, when the numerical range is expressed as A to B, the numerical value range includes the values of the lower limit A and the upper limit B.

[Display device with touch panel]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of a display device with a touch panel according to the present embodiment. As shown in the figure, the display device with a touch panel is configured by bonding the display device 10 and the touch panel 20 through an adhesive layer 30.

The display device 10 is configured by laminating a polarizing plate 2 on a display panel 1. The display panel 1 can be configured by a liquid crystal display panel (LCD: Liquid Crystal Display) or an organic EL (OLED: Organic light-Emitting Diode) display. LCDs and OLEDs have a plurality of pixels arranged in a matrix, and display is performed by turning on / off the driving of each pixel by a switching element such as a TFT (Thin Film Transistor). When the display panel 1 is an LCD, another polarizing plate (not shown) is disposed on the opposite side of the display panel 1 from the polarizing plate 2.

The polarizing plate 2 includes a polarizer 3 that transmits predetermined linearly polarized light, a film 4 that is laminated on the touch panel 20 side of the polarizer 3, and a film 5 that is laminated on the display panel 1 side of the polarizer 3 (back surface protective film). ) And. The polarizer 3 is obtained by, for example, dyeing a polyvinyl alcohol film with a dichroic dye and stretching the film at a high magnification. After being subjected to an alkali treatment (also referred to as a saponification treatment), the above-described films 4 and 5 are converted into the polarizer 3. The adhesive is bonded to each of these surfaces via an ultraviolet curable adhesive, and the solvent is removed by drying and the adhesive is cured by ultraviolet irradiation (UV irradiation).

The film 4 is configured as a hard coat film in which a hard coat layer 4b is laminated on a film substrate 4a (surface protective film), and has a function of protecting the surface of the polarizing plate 2 (polarizer 3). Yes. The film substrate 4a can be composed of various materials, but in the present embodiment, among them, it is composed of a cellulose ester film having a thickness of 15 to 30 μm. Cellulose ester film, the moisture permeability is as high as about 800g ^/ m 2 ^/ 24h with a thickness 80μm terms has excellent hygroscopicity.

The hard coat layer 4b is made of, for example, an active energy ray-curable resin and has a thickness of several μm. Although the film 4 may be configured as a protective film by itself (without laminating a hard coat layer) alone, the film 4 may be a hard coat film in which a hard coat layer 4b is formed on the film substrate 4a. The function of protecting the surface of the polarizing plate 2 can be enhanced. Particularly in the present embodiment, since the film substrate 4a is a thin film, the display panel 1 is easily damaged when the touch panel is pressed. However, by using the film 4 as a hard coat film, such damage is caused. Occurrence can be suppressed.

The film substrate 4a has a plasticizer. Although details of the plasticizer material will be described later, this plasticizer is added to the cellulose ester film for the purpose of improving moisture permeability, fluidity of the composition, and flexibility of the film. The cellulose ester film can be formed by a solution casting film forming method, which will be described later. At this time, since the solvent evaporates on the support on which the dope is cast, the plasticizer is in the thickness direction of the film. It becomes easy to be unevenly distributed. That is, the concentration of the plasticizer increases on one side than the center in the thickness direction of the film, and decreases on the other side. In the present embodiment, in the film substrate 4a, the surface (namely, the harder surface) opposite to the surface (namely, the softer surface) on which the plasticizer is unevenly distributed in the thickness direction is polarized. A bonding surface with the child 3 is used, and the bonding surface and the polarizer 3 are bonded to each other with an ultraviolet curable adhesive.

In addition, the surface on the side where a lot of plasticizers are unevenly distributed can be identified by, for example, analysis with a time-of-flight secondary ion mass spectrometer (TOF-SIMS).

The hard coat layer 4b described above is formed on the surface of the film substrate 4a on which the plasticizer is unevenly distributed (the surface on the side opposite to the polarizer 3).

In addition, when the display panel 1 is OLED, it is preferable that the polarizing plate 2 is comprised as a circularly-polarizing plate (or elliptical polarizing plate) for external light reflection prevention. In the case of a circularly polarizing plate, the film 5 on the display panel 1 side of the polarizer 3 is an optical film that imparts an in-plane retardation of about ¼ of the wavelength to the transmitted light. It is preferable that the polarizer 3 and the film 5 are bonded together so that the axis (transmission axis or absorption axis) and the slow axis of the film 5 intersect at an angle of about 45 °.

When the display panel 1 is an LCD, the film 5 may be provided simply as a protective film for a polarizer, or may be a protective film that also serves as a retardation film having a desired optical compensation function. As described above, when the display panel 1 is an OLED display, the film 5 is preferably an optical film that imparts an in-plane retardation of about ¼ of the transmission wavelength.

Moreover, the film 5 in this embodiment is comprised with the optical film whose water vapor transmission rate is 200 g / m < ² > / 24h or less. As such an optical film, a film made of acrylic, cyclic polyolefin (COP), or polycarbonate (PC) resin can be used. By the way, the moisture permeability of acrylic 100g ^/ m 2 ^/ 24h. A 40 [mu] m, the moisture permeability of the COP 0.1g ^/ m 2 ^/ 24h. Is 40μm, moisture permeability of the PC is 100g ^/ m 2 ^/ 24h. It is about 40 μm. In addition, the moisture permeability in this invention represents what was measured on test conditions 40 degreeC and 90% RH.

This optical film moisture permeability exceeding 200g / m 2 / ^24h, since provided in the display panel 1 side of the polarizer 3, when the phase difference of the optical film is changed by moisture, from the display panel 1 This is because the polarization state of light is changed by the optical film, and the amount of light may decrease when passing through the polarizer 3. On the other hand, the scattering prevention film 25 and the surface protection film (film substrate 4a), which will be described later, provided outside the polarizer 3 have no influence on the polarization state even if the phase difference fluctuates due to moisture. In addition, a cellulose ester film having high water absorption can be preferably used.

The touch panel 20 is a capacitive touch panel, and has an electrode pattern 22 (electrode layer) made of a transparent conductive film (for example, ITO) and an interlayer insulating layer 23 on a glass substrate 21. That is, in the touch panel 20, only one glass substrate 21 is used, and the thin touch panel 20 is configured as compared with the configuration using two glass substrates.

The surface of the glass substrate 21 (the surface opposite to the electrode pattern 22) is a touch surface of the touch panel 20. The electrode pattern 22 is formed on the glass substrate 21 so as to extend in one direction (for example, the X direction). The interlayer insulating layer 23 is formed on the glass substrate 21 so as to cover the electrode pattern 22.

When the surface of the touch panel 20 is pressed with a finger, the electrode pattern 22 is grounded through the human body at the touched point, and the resistance value between the electrode pattern 22 and the ground line changes. By detecting the change in the resistance value by an external detection circuit connected to the electrode pattern 22, the coordinates of the touched point are specified.

Also, a conductive film 24 is bonded onto the electrode pattern 22 (on the interlayer insulating layer 23) via an adhesive layer (not shown). The conductive film 24 includes a scattering prevention film 25 and a conductive layer 26.

The scattering prevention film 25 includes a cellulose ester film, and is provided to prevent the glass substrate 21 from scattering due to external impact or the like. As the cellulose ester film, a cellulose triacetate film having a retardation Ro in the in-plane direction of 0 nm to 10 nm can be used. In this case, since there is little interference due to the phase difference in the in-plane direction, it is possible to improve the visibility when viewing the display panel 10 with the naked eye via the touch panel 20.

When the retardation Ro in the in-plane direction of the scattering prevention film 25 is 0 nm to 10 nm, the bonding angle of the scattering prevention film 25 with respect to the polarizer 3 is preferably 0 ° to 15 °. Here, the bonding angle is an angle formed by the optical axis (transmission axis or absorption axis) of the polarizer 3 and the slow axis of the scattering prevention film 25. At this time, the direction of the slow axis of the anti-scattering film 25 is determined by an Abbe refractometer (1T) in an in-plane average refractive index at a light wavelength of 590 nm under an environment of a temperature of 23 ° C. and a relative humidity of 55% RH. Can be obtained by measuring. By setting it as such an angle, even when the retardation of the in-plane direction of a scattering prevention film changes a little, an optical influence can be reduced.

Further, as the cellulose ester film of the anti-scattering film 25, a cellulose diacetate film having a retardation Ro in the in-plane direction of 30 nm to 200 nm may be used. In this case, it is preferable that the anti-scattering film is disposed so that the slow axis thereof is in the direction of 10 to 80 ° with respect to the optical axis (transmission axis or absorption axis) of the polarizer 3. With such a configuration, the linearly polarized light transmitted through the polarizer 3 can be changed to elliptically polarized light or circularly polarized light, so that the visibility when viewing the display device 10 with polarized sunglasses can be improved. .

The conductive layer 26 is formed by water-based application of a conductive material on the side opposite to the electrode pattern 22 with respect to the scattering prevention film 25. As said conductive material, the conductive fiber and conductive polymer which consist of metal nanowires, such as silver nanowire (AgNW) and copper nanowire (CuNW), can be used, and a conductive fiber is used preferably especially. Details of the conductive fibers such as metal nanowires will be described later.

The pressure-sensitive adhesive layer 30 is composed of an adhesive layer such as OCA or UV curable resin (OCR), and is formed on the entire surface of the polarizing plate 2 of the display device 10 to join the touch panel 20 and the display device 10 together. Yes.

According to said structure, since the electrode layer on the glass substrate 21 is one layer of the electrode pattern 22 in the touch panel 20, compared with the structure of two electrode layers, the electrode layer at the time of cutting the glass substrate 21 It is possible to suppress a decrease in yield due to the disconnection of wire and thus a decrease in productivity of the touch panel 20.

Further, since the conductive film 24 bonded on the electrode pattern 22 has the scattering prevention film 25, the scattering prevention film 25 can prevent the scattering of the glass substrate 21 due to impact or the like. Further, in a thin configuration in which a single glass substrate is used, the touch panel 20 is close to the display device 10 and easily receives electrical noise from the display device 10. However, since the conductive film 24 includes the conductive layer 26, the electrical noise can be blocked by the conductive layer 26. Therefore, even if such a thin configuration is used, an error of the touch panel 20 due to the electrical noise is caused. Operation can be suppressed.

In particular, by using conductive fibers made of metal nanowires as a conductive material and applying this to water, the conductive layer 26 that blocks electrical noise can be reliably realized.

In the case where the film 4 and the film 5 of the polarizing plate 3 are bonded to the polarizer 3 through an ultraviolet curable adhesive, the film 4 includes a cellulose ester film, and the plasticizer in the cellulose ester film Is bonded to the polarizer 3 through a surface opposite to the surface on the side where a large amount of is unevenly distributed. Thereby, while suppressing the curing shrinkage of the adhesive at the time of UV irradiation, a lot of plasticizer is arranged on the surface on the touch panel 20 side, and the stress when the touch panel 20 is pressed is absorbed by the cellulose ester film. be able to. As a result, disorder of the orientation of the polarizer 3 can be suppressed, and a decrease in contrast can be suppressed.

Further, when the hard coat layer 4b is provided on the surface of the film 4 (cellulose ester film) on the side with a large amount of plasticizer, the surface of the film 4 becomes soft and easily absorbs stress when the touch panel 20 is pressed. Therefore, the hard coat film can be made difficult to break.

Further, the film 5 of the polarizing plate 3 includes the following optical film moisture permeability 200g ^/ m 2 ^/ 24h. Thereby, the water | moisture content of the conductive layer 26 formed by the above-mentioned aqueous coating and the water | moisture content of the polarizer 3 become difficult to permeate | transmit the film 5, and it can suppress that the phase difference of the film 5 fluctuates with said water | moisture content. . As a result, it is possible to suppress display unevenness such as white spots during black display.

Particularly, by using a film made of any one of acrylic, cyclic polyolefin, and polycarbonate as the optical film having low moisture permeability, the above effect can be obtained with certainty.

Further, since the glass substrate is located on the outermost surface of the touch panel 20, the moisture cannot escape to the outside of the touch panel 20 and is confined between the glass substrate 21 and the film 5. However, both the scattering prevention film 25 of the conductive film 24 and the film 4 of the polarizing plate 3 contain cellulose ester films having high hygroscopicity and high moisture permeability, so that the moisture is trapped (captured) by both cellulose ester films. )can do. Thereby, it can suppress that the polarizer 3 deteriorates with the said water | moisture content, and can suppress that it becomes a reddish display at the time of black display.

Further, since the cellulose ester film included in the film 4 is as thin as 15 to 30 μm, water easily escapes from the polarizer 3 through the film 4 to the scattering prevention film 25, and the polarizer 3 is deteriorated by moisture. Can be reliably suppressed.

[About polarizing plate]
Hereinafter, the detail of each layer which comprises the above-mentioned polarizing plate 2 is demonstrated. In addition, about the protective film (surface protective film, back surface protective film) and hard coat layer shown below, it can be applied also to the scattering prevention film 25 of the touch panel 20.

[Protective film]
A film substrate 4a which is a protective film on the touch panel 20 side of the polarizing plate 2 is composed of a cellulose ester film having a thickness of 15 to 30 μm. The cellulose ester resin used will be described in detail later.

The film 5 is a protective film of the display panel 1 side of the polarizing plate 2 is not particularly limited and may be a thermoplastic resin or a thermosetting resin, moisture permeability is less than 200 g / m 2 / ^24h Film Specifically, it is desirable to use an optical film made of acrylic resin, cyclic polyolefin (COP), polycarbonate (PC), or the like.

(Thermoplastic resin)
The thermoplastic resin that can be used for the film 5 refers to a resin that becomes soft when heated to a glass transition temperature or a melting point and can be molded into a desired shape.

General thermoplastic resins include cellulose esters, polyethylene (PE), high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene. (PS), polyvinyl acetate (PVAc), Teflon (registered trademark) (polytetrafluoroethylene, PTFE), ABS resin (acrylonitrile butadiene styrene resin), AS resin, acrylic resin (PMMA), or the like can be used.

Especially when strength and resistance to breakage are required, polyamide (PA), nylon, polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE, PPO), polybutylene terephthalate (PBT) Polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate (GF-PET), cyclic polyolefin (COP), and the like can be used.

Furthermore, when high heat distortion temperature and long-term use characteristics are required, polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer, polyether Ether ketone, thermoplastic polyimide (PI), polyamideimide (PAI), or the like can be used.

In the present embodiment, from the viewpoint of manifesting the effects of the present embodiment, it is preferable to use a cellulose ester resin as the film substrate 4a, and as the film 5, a polycarbonate resin, a polyethylene terephthalate resin, an acrylic resin, or a polyolefin resin. Is preferably used.

Hereinafter, in this embodiment, the cellulose ester resin used suitably for the film base material 4a will be described in detail.

<Cellulose ester resin>
Cellulose ester resins that can be used for the film 4a in this embodiment are cellulose (di, tri) acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose. It is preferably at least one selected from phthalates.

Among these, particularly preferred cellulose esters include cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate.

As the substitution degree of the mixed fatty acid ester, more preferable cellulose acetate propionate and lower fatty acid ester of cellulose acetate butyrate have an acyl group having 2 to 4 carbon atoms as a substituent, and the substitution degree of the acetyl group is X. When the substitution degree of propionyl group or butyryl group is Y, it is preferably a cellulose resin containing a cellulose ester that simultaneously satisfies the following formulas (I) and (II).
Formula (I) 2.6 ≦ X + Y ≦ 3.0
Formula (II) 1.0 ≦ X ≦ 2.5

Of these, cellulose acetate propionate is particularly preferably used. Among them, 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9 are preferable. The part not substituted with the acyl group is usually present as a hydroxyl group. These can be synthesized by known methods.

Further, the cellulose ester used in the present embodiment is preferably one having a weight average molecular weight Mw / number average molecular weight Mn ratio of 1.5 to 5.5, particularly preferably 2.0 to 5.0, The cellulose ester is more preferably 2.5 to 5.0, and more preferably 3.0 to 5.0 cellulose ester.

The raw material cellulose of the cellulose ester used in this embodiment may be wood pulp or cotton linter. The wood pulp may be coniferous or hardwood, but coniferous is more preferred. A cotton linter is preferably used from the viewpoint of releasability during film formation. The cellulose ester made from these can be mixed suitably or can be used independently.

For example, the ratio of cellulose ester derived from cellulose linter: cellulose ester derived from wood pulp (coniferous): cellulose ester derived from wood pulp (hardwood) is 100: 0: 0, 90: 10: 0, 85: 15: 0, 50:50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0: 15, 40:30:30 can be used. .

In this embodiment, 1 g of cellulose ester resin is added to 20 ml of pure water (electric conductivity of 0.1 μS / cm or less, pH 6.8), and the pH when stirred in a nitrogen atmosphere at 25 ° C. for 1 hr. Preferably, the electrical conductivity is 6 to 7 and the electrical conductivity is 1 to 100 μS / cm.

[Film production method]
As a method for producing a film substrate, production methods such as a normal inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, and a hot press method can be used. A casting method such as a melt casting film forming method is preferably used. In addition, about the film base material (cellulose ester film) of a surface protection film, since it is necessary to make a plasticizer unevenly distribute in a film thickness direction, it forms into a film by the solution casting film forming method especially. Hereinafter, the preferable manufacturing method of a film base material is demonstrated.

<Manufacturing method of base material by solution casting film forming method>
1) Dissolution Step The dissolution step is a step in which a dope is formed by dissolving a thermoplastic resin, a heat-shrinkable material, and other additives in an organic solvent mainly composed of a good solvent for the thermoplastic resin while stirring. is there. A good solvent refers to an organic solvent having good solubility in a thermoplastic resin in an optical film manufacturing method by a solution casting film forming method, and also shows a main effect on dissolution, among which a large amount The organic solvent used in the above is called a main (organic) solvent or a main (organic) solvent.

For the dissolution of the thermoplastic resin, a method carried out at normal pressure, a method carried out below the boiling point of the main solvent, a method carried out under pressure above the boiling point of the main solvent, JP-A-9-95544, JP-A-9-95557 Alternatively, various dissolution methods such as a method using a cooling dissolution method as described in JP-A-9-95538 and a method using a high pressure as described in JP-A-11-21379 can be used. The method of pressurizing at a boiling point or higher is preferred.

* Recycled materials are also reused. The return material refers to a material obtained by finely pulverizing a film, which is generated when a film is formed, a material obtained by cutting off both sides of the film, or a film raw material that has been speculated out due to scratches or the like.

2) Casting process In the casting process, the dope is fed to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump), and transferred to an endless metal belt such as a stainless steel belt or a rotating metal. This is a step of casting a dope from a pressure die slit to a casting position on a metal support such as a drum.

¡Pressure dies that can adjust the slit shape of the die base and make the film thickness uniform are preferred. Examples of the pressure die include a coat hanger die and a T die, and any of them is preferably used. The surface of the metal support is a mirror surface. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked. Or it is also preferable to obtain the film of a laminated structure by the co-casting method which casts several dope simultaneously.

3) Solvent evaporation process The solvent evaporation process is a process in which a web (a dope film formed by casting a dope on a casting support) is heated on the casting support to evaporate the solvent.

To evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back side of the support by a liquid, a method of transferring heat from the front and back by radiant heat, and the like. High efficiency and preferable. A method of combining them is also preferably used. The web on the support after casting is preferably dried on the support in an atmosphere of 40 to 100 ° C. In order to maintain the atmosphere at 40 to 100 ° C., it is preferable to apply hot air at this temperature to the upper surface of the web or heat by means such as infrared rays.

From the viewpoint of surface quality, moisture permeability, and peelability, it is preferable to peel the web from the support within 30 to 120 seconds.

4) Peeling process A peeling process is a process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process.

The temperature at the peeling position on the metal support is preferably 10 to 40 ° C, more preferably 11 to 30 ° C.

The amount of residual solvent at the time of peeling of the web on the metal support at the time of peeling is preferably 50 to 120% by mass depending on the strength of drying conditions, the length of the metal support, and the like. If the web is peeled off at a time when the amount of residual solvent is larger, if the web is too soft, the flatness at the time of peeling will be lost, and slippage and vertical stripes are likely to occur due to the peeling tension. The amount of solvent is determined.

The residual solvent amount of the web is defined by the following formula.
Residual solvent amount (%) = (mass before web heat treatment−mass after web heat treatment) / (mass after web heat treatment) × 100
Note that the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.

The peeling tension when peeling the metal support and the film is usually 196 to 245 N / m. If wrinkles easily occur during peeling, it is preferable to peel with a tension of 190 N / m or less, and further peel with a minimum tension that can be peeled up to 166.6 N / m, and then with a minimum tension of 137.2 N / m. Although it is preferable, it is particularly preferable to peel at a minimum tension of -100 N / m.

In this embodiment, the temperature at the peeling position on the metal support is preferably −50 to 40 ° C., more preferably 10 to 40 ° C., and most preferably 15 to 30 ° C.

5) Drying and stretching step In the drying and stretching step, after peeling, a drying device that transports the web alternately through a plurality of rolls arranged in the drying device, and / or a tenter that clips and transports both ends of the web with clips. This is a step of drying the web using a stretching device.

The drying means is generally one that blows hot air on both sides of the web, but there is also a means for heating by applying microwaves instead of wind. Too rapid drying tends to impair the flatness of the resulting film. Drying at a high temperature is preferably performed from about 8% by mass or less of the residual solvent. Throughout, drying is generally performed at 40-250 ° C. In particular, drying at 40 to 160 ° C. is preferable.

When using a tenter stretching apparatus, it is preferable to use an apparatus that can independently control the film gripping length (distance from the start of gripping to the end of gripping) left and right by the left and right gripping means of the tenter. In the tenter process, it is also preferable to intentionally create sections having different temperatures in order to improve planarity.

It is also preferable to provide a neutral zone between different temperature zones so that each zone does not cause interference.

The stretching operation may be performed in multiple stages, and it is also preferable to perform biaxial stretching in the casting direction and the width direction. When biaxial stretching is performed, simultaneous biaxial stretching may be performed or may be performed stepwise.

In this case, stepwise means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any one of the stages. Is also possible. That is, for example, the following stretching steps are possible.

a) Stretch in the casting direction-Stretch in the width direction-Stretch in the casting direction-Stretch in the casting direction b) Stretch in the width direction-Stretch in the width direction-Stretch in the casting direction-Stretch in the casting direction

In addition, simultaneous biaxial stretching includes stretching in one direction and contracting the other while relaxing the tension. The preferred draw ratio of simultaneous biaxial stretching can be in the range of x1.01 to x1.5 times in both the width direction and the longitudinal direction.

The amount of residual solvent of the web when stretching is preferably 20 to 100% by mass at the start of stretching, and drying is preferably performed while stretching until the amount of residual solvent of the web is 10% by mass or less. More preferably, it is 5% by mass or less.

The drying temperature when stretching is preferably 30 to 160 ° C, more preferably 50 to 150 ° C, and most preferably 70 to 140 ° C.

In the stretching step, it is preferable that the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the film, and the temperature distribution in the width direction in the stretching step is preferably within ± 5 ° C, and within ± 2 ° C. Is more preferable, and within ± 1 ° C. is most preferable.

6) Winding process The winding process is a process in which the amount of residual solvent in the web is 2% by mass or less and is wound as a film by a winder, and the amount of residual solvent is 0.4% by mass or less. Thus, a film having good dimensional stability can be obtained. It is particularly preferable to wind up at 0.00 to 0.10% by mass.

As a winding method, a generally used one may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, etc., and these may be used properly.

The protective film according to this embodiment is preferably a long film. Specifically, the protective film has a thickness of about 100 m to 5000 m and is usually provided in a roll shape. The film width is preferably 1.3 to 4 m, more preferably 1.4 to 2 m.

<Manufacturing method of base material by melt casting film forming method>
Next, the method in the case of manufacturing a back surface protective film by the melt casting film forming method will be described.

<Melted pellet manufacturing process>
The composition containing a resin used for melt extrusion is usually preferably kneaded in advance and pelletized.

Pelletization may be performed by a known method, for example, an additive consisting of a dried thermoplastic resin and a heat-shrinkable material is supplied to an extruder with a feeder, and kneaded using a single-screw or twin-screw extruder, It can be pelletized by extruding into a strand from a die, water cooling or air cooling, and cutting.

It is important to dry the raw material before extruding to prevent the raw material from being decomposed. In particular, since cellulose ester easily absorbs moisture, it is preferable to dry it at 70 to 140 ° C. for 3 hours or more with a dehumidifying hot air dryer or a vacuum dryer so that the moisture content is 200 ppm or less, and further 100 ppm or less.

Additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders. Moreover, in order to mix a small amount of additives, such as particle | grains and antioxidant, uniformly, it is preferable to mix beforehand.

The antioxidant may be mixed with each other, and if necessary, the antioxidant may be dissolved in a solvent, impregnated with a thermoplastic resin and mixed, or mixed by spraying. May be.

From the viewpoint that drying and mixing can be performed simultaneously, it is preferable to use a vacuum nauter mixer or the like. Further, if the contact with air, such as the exit from the feeder unit or die, it is preferable that the atmosphere such as dehumidified air and dehumidified N ₂ gas.

The extruder is preferably processed at as low a temperature as possible so as to be able to be pelletized so that the shear force is suppressed and the resin does not deteriorate (molecular weight reduction, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.

Film formation is performed using the pellets obtained as described above. It is also possible to feed the raw material powder directly to the extruder with a feeder and form a film as it is without pelletization.

<Process for extruding molten mixture from die to cooling roll>
First, the pellets produced are extruded using a single-screw or twin-screw extruder, the melting temperature Tm during extrusion is set to about 200 to 300 ° C., filtered through a leaf disk type filter or the like to remove foreign matter, and then the T-die The film is coextruded into a film, solidified on a cooling roll, and cast while pressing with an elastic touch roll. Tm is the temperature of the die exit portion of the extruder.

When introducing from the supply hopper to the extruder, it is preferable to prevent oxidative decomposition or the like under vacuum, reduced pressure, or inert gas atmosphere.

∙ If foreign matter such as scratches or plasticizer aggregates adheres to the die, streaky defects may occur. Such defects are also referred to as die lines, but in order to reduce surface defects such as die lines, it is preferable to have a structure in which the resin retention portion is minimized in the piping from the extruder to the die. . It is preferable to use a die that has as few scratches as possible inside the lip.

The inner surface that comes into contact with the molten resin, such as an extruder or a die, is preferably subjected to surface treatment that makes it difficult for the molten resin to adhere to the surface by reducing the surface roughness or using a material with low surface energy. Specifically, a hard chrome plated or ceramic sprayed material is polished so that the surface roughness is 0.2 S or less.

The cooling roll is not particularly limited, but may be a roll having a structure in which a heat medium or a cooling medium capable of temperature control flows through a highly rigid metal roll. Although the size of the cooling roll is not limited, it may be sufficient to cool the melt-extruded film, and the diameter of the cooling roll is usually about 100 mm to 1 m.

The surface material of the cooling roll includes carbon steel, stainless steel, aluminum, titanium and the like. Further, in order to increase the hardness of the surface or improve the releasability from the resin, it is preferable to perform a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying.

The surface roughness of the cooling roll surface is preferably 0.1 μm or less in terms of Ra, and more preferably 0.05 μm or less. The smoother the roll surface, the smoother the surface of the resulting film. Of course, it is preferable that the surface processed is further polished to have the above-described surface roughness.

Examples of the elastic touch roll include JP-A-03-124425, JP-A-08-224772, JP-A-07-1000096, JP-A-10-272676, WO97 / 028950, JP-A-11-235747, JP-A-2002-2002. It is possible to use a silicon rubber roll whose surface is coated with a thin film metal as described in JP-A-36332, JP-A-2005-172940 and JP-A-2005-280217.

When peeling the film from the cooling roll, it is preferable to control the tension to prevent deformation of the film.

[Production method of composite resin film]
The film base material of this embodiment can be comprised with a composite resin film. As a method for producing a composite resin film, it can be produced by a production method of an embodiment having a film forming step by a coextrusion method.

<Co-extrusion method>
In the present embodiment, a film having a laminated structure can also be produced by a coextrusion method. For example, a film having a structure of skin layer / core layer / skin layer can be produced. For example, the matting agent can be contained in the skin layer in a large amount or only in the skin layer. The plasticizer and the ultraviolet absorber can be contained in the core layer more than the skin layer, and may be contained only in the core layer. In addition, the type of plasticizer and ultraviolet absorber can be changed between the core layer and the skin layer. For example, the skin layer contains a low-volatile plasticizer and / or an ultraviolet absorber, and the core layer has excellent plasticity. It is also possible to add a plasticizer or an ultraviolet absorber excellent in ultraviolet absorption. The glass transition temperature of the skin layer and the core layer may be different, and the glass transition temperature of the core layer is preferably lower than the glass transition temperature of the skin layer. At this time, the glass transition temperatures of both the skin and the core can be measured, and an average value calculated from these volume fractions can be defined as the glass transition temperature Tg and similarly handled. Also, the viscosity of the melt containing the cellulose ester during melt casting may be different between the skin layer and the core layer, and the viscosity of the skin layer> the viscosity of the core layer or the viscosity of the core layer ≧ the viscosity of the skin layer may be used.

The above-mentioned co-extrusion method uses a plurality of extruders to heat and melt the resin to be laminated from each other, and after the respective resins are merged, co-extrusion is performed from the slit-shaped discharge port of the T die. Is a method of forming a cast sheet (unstretched state) by cooling and solidifying. As a method of joining the molten resin and extruding the sheet from the T-die, a feed block method in which the molten resin is joined and then the manifold is widened, and a multi-manifold method in which the molten resin is spread by the manifold and then joined together. Either of them can be used.

〔Additive〕

(Antioxidant)
The film substrate preferably contains an antioxidant as an additive. Preferred antioxidants are phosphorous or phenolic, and it is more preferred to combine phosphorous and phenolic simultaneously. Hereinafter, the antioxidant that can be suitably used in the present embodiment will be described.

<Phenolic antioxidant>
In this embodiment, a phenolic antioxidant is preferably used, and a hindered phenol compound is particularly preferably used.

<Phosphorus antioxidant>
As the phosphorus antioxidant, phosphorus compounds such as phosphite, phosphonite, phosphinite, or tertiary phosphane can be used. A conventionally known compound can be used as the phosphorus compound. For example, Japanese Patent Application Laid-Open Nos. 2002-138188, 2005-344444, paragraph numbers 0022 to 0027, Japanese Patent Application Laid-Open No. 2004-182979, paragraphs 0023 to 0039, Japanese Patent Application Laid-Open Nos. 10-306175, 1-254744, and Japanese Patent Application Laid-Open No. -270892, JP-A-5-202078, JP-A-5-178870, JP-T-2004-504435, JP-T-2004-530759, and JP-A-2005-353229. Is preferred.

The addition amount of the phosphorus compound is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the resin.

(Other antioxidants)
Dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropionate) Nate) and other sulfur-based antioxidants, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy -3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl acrylate, a heat resistant processing stabilizer such as 3,4-dihydro-2H-1 described in JP-B-08-27508 -Benzopyran compounds, 3,3'-spirodichroman compounds, 1,1-spiroindane compounds, morpholine, thiomorpho Emissions, thiomorpholine oxide, thiomorpholine dioxide, a compound having a piperazine skeleton partial structure, oxygen scavenger dialkoxy benzene type compound in JP-03-174150 describes the like. These antioxidant partial structures may be part of the polymer or regularly pendant into the polymer and introduced into part of the molecular structure of additives such as plasticizers, acid scavengers, and UV absorbers. It may be.

(Other additives)
In addition to the above-described compounds, the film substrate according to the present embodiment can contain various compounds as additives depending on the purpose.

<Acid scavenger>
The acid scavenger preferably comprises an epoxy compound as an acid scavenger described in US Pat. No. 4,137,201. Epoxy compounds as such acid scavengers are known in the art and are derived by condensation of diglycidyl ethers of various polyglycols, particularly about 8-40 moles of ethylene oxide per mole of polyglycol. Metal glycol compounds such as polyglycols, diglycidyl ethers of glycerol (eg, those conventionally used in and together with vinyl chloride polymer compositions), epoxidized ether condensation products, bisphenol A Diglycidyl ethers (ie, 4,4'-dihydroxydiphenyldimethylmethane), epoxidized unsaturated fatty acid esters (especially esters of alkyls of about 2 to 2 carbon atoms of fatty acids of 2 to 22 carbon atoms (eg Butyl epoxy stealey ), And various epoxidized long chain fatty acid triglycerides, etc. (eg, epoxidized vegetable oils and other unsaturated natural oils, which are sometimes epoxidized, which can be represented and exemplified by compositions such as epoxidized soybean oil) These are referred to as natural glycerides or unsaturated fatty acids and these fatty acids generally contain 12 to 22 carbon atoms)).

<Light stabilizer>
Light stabilizers include hindered amine light stabilizer (HALS) compounds, which are known compounds, such as US Pat. No. 4,619,956, columns 5-11 and US Pat. , 839, 405, as described in columns 3 to 5, including 2,2,6,6-tetraalkylpiperidine compounds, or acid addition salts thereof, or complexes of these with metal compounds It is. Furthermore, the light stabilizer described in JP 2007-63311 A can be used.

<Ultraviolet absorber>
As the ultraviolet absorber, from the viewpoint of preventing deterioration due to ultraviolet rays, those having excellent absorption ability of ultraviolet rays having a wavelength of 370 nm or less and those having little absorption of visible light having a wavelength of 400 nm or more are preferable from the viewpoint of liquid crystal display properties. Examples include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, etc., but benzophenone compounds and less colored benzotriazole compounds preferable. Further, ultraviolet absorbers described in JP-A-10-182621 and JP-A-8-337574, and polymer ultraviolet absorbers described in JP-A-6-148430 may be used.

In this embodiment, it is preferable to add the ultraviolet absorber in an amount of 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and further preferably 1 to 5% by mass. Two or more of these may be used in combination.

<Matting agent>
Fine particles such as a matting agent can be added to the film substrate of the present embodiment, and examples of the fine particles include inorganic compound fine particles and organic compound fine particles. Examples of the fine particles include inorganic fine particles such as silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate. Crosslinked polymer fine particles can be mentioned. Among these, silicon dioxide is preferable because it can reduce the haze of the resin substrate. In many cases, fine particles such as silicon dioxide are surface-treated with an organic material, but such particles are preferable because they can reduce the haze of the resin substrate.

<Plasticizer>
A plasticizer can be used in combination with the cellulose ester film in order to improve moisture permeability, fluidity of the composition, and flexibility of the film. Examples of the plasticizer include phthalate esters, fatty acid esters, trimellitic esters, phosphate esters, polyesters, sugar esters, acrylic polymers, and the like. Among these, from the viewpoint of moisture permeability, polyester-based and sugar ester-based polymer plasticizers are preferably used.

These plasticizers are preferably added in an amount of 0.5 to 30 parts by mass with respect to 100 parts by mass of the cellulose ester film.

[Hard coat layer]
A hard coat layer may be formed on the surface of the surface protective film (film substrate 4a) for the purpose of surface protection. The hard coat layer is preferably composed of, for example, an active energy ray curable resin.

(Active energy ray-curable resin)
The active energy ray-curable resin refers to a resin that cures through a crosslinking reaction or the like by irradiation with active rays such as ultraviolet rays or electron beams, and specifically, a resin having an ethylenically unsaturated group. More specifically, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, an ultraviolet curable epoxy resin, or the like is preferably used. Of these, ultraviolet curable acrylate resins are preferred.

As the ultraviolet curable acrylate resin, polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or methacryloyloxy groups in the molecule.

The compounding amount of the active energy ray-curable resin in the hard coat layer composition is usually 10 to 99 parts by mass, preferably 35 to 99 parts by mass, when the total composition is 100 parts by mass. When the blending amount of the active energy ray-curable resin is small, it is difficult to sufficiently obtain the film strength of the hard coat layer. Moreover, when there are many compounding quantities, since malfunctions, such as a film thickness uniformity at the time of apply | coating with the well-known coating method mentioned later and an application | coating stripe | line | muscle generate | occur | produce, it is not preferable.

(Cationically polymerizable compound)
The hard coat layer may further contain a cationically polymerizable compound. The cationically polymerizable compound is a resin that undergoes cationic polymerization by energy active ray irradiation or heat. Specific examples include an epoxy group, a cyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester compound, and a vinyloxo group. Among them, a compound having a functional group such as an epoxy group or a vinyl ether group is preferably used in this embodiment.

When the hard coat layer composition contains the cationic polymerizable compound, the compounding amount of the cationic polymerizable compound in the hard coat layer composition is usually 1 to 90 parts by weight when the entire composition is 100 parts by weight. The amount is preferably 1 to 50 parts by mass.

(Fine particles)
The hard coat layer may contain fine particles. Examples of the fine particles include inorganic fine particles and organic fine particles. As inorganic particles, silica, titanium oxide, aluminum oxide, tin oxide, indium oxide, ITO, zinc oxide, zirconium oxide, magnesium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated Mention may be made of calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. As organic particles, polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicon resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin powder, melamine resin powder, Examples thereof include polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, and polyfluorinated ethylene resin powder. The average particle diameter of these fine particles is preferably 30 nm to 200 nm in view of the stability and clearness of the hard coat layer coating composition. The hard coat layer may contain two or more kinds of fine particles having different particle sizes. From the viewpoint of easily achieving the desired pencil hardness, the hard coat layer preferably contains silica fine particles.

Also, from the viewpoint of better exhibiting the effects of the present embodiment, it is preferable that the hard coat layer contains reactive silica fine particles (Xa) surface-treated with an organic compound having a polymerizable unsaturated group.

The hard coat layer preferably contains the above-mentioned active energy ray-curable resin and fine particles, and the active mass ray-curable resin: fine particles = 90: 10 to 20:80 in terms of the mass ratio.

(Other additives, manufacturing method of hard coat layer)
The hard coat layer preferably further contains a photopolymerization initiator in order to accelerate the curing of the active energy ray-curable resin. The blending amount of the photopolymerization initiator is preferably, as a mass ratio, photopolymerization initiator: active energy ray-curable resin = 20: 100 to 0.01: 100.

Specific examples of the photopolymerization initiator include alkylphenone series, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto. It is not a thing. Commercially available products may be used, and preferred examples include Irgacure 184, Irgacure 907, and Irgacure 651 manufactured by BASF Japan.

Further, the hard coat layer may contain an ultraviolet absorber similar to the above-described ultraviolet absorber.

Furthermore, the hard coat layer is composed of two or more layers, and the hard coat layer in contact with the film substrate contains an ultraviolet absorber, so that the objective effect of the present embodiment is satisfactorily exhibited, and the hard coat layer The film strength (abrasion resistance) and the pencil hardness are preferred from the viewpoint of obtaining good results. The content of the UV absorber is preferably, as a mass ratio, UV absorber: hard coat layer composition = 0.01: 100 to 10: 100.

When two or more hard coat layers are provided, the thickness of the hard coat layer in contact with the film substrate is preferably in the range of 0.05 to 2 μm. Two or more layers may be formed as a simultaneous multilayer. The simultaneous multi-layering is to form a hard coat layer by applying two or more hard coat layers on a base material without going through a drying step. In order to laminate the second hard coat layer on the first hard coat layer without using a drying process, the layers are stacked one after another with an extrusion coater or simultaneously with a slot die having a plurality of slits. Can be done.

In addition, as a method for producing a hard coat layer, a hard coat layer coating composition diluted with a solvent that swells or partially dissolves a cellulose ester film is applied, dried and cured on the cellulose ester film by the following method. The method of providing is preferable from the viewpoint that interlayer adhesion between the hard coat layer and the cellulose ester film is easily obtained.

As the solvent for swelling or partially dissolving the cellulose ester film, a solvent containing a ketone and / or an acetate ester is preferable. Specifically, examples of the ketone include methyl ethyl ketone, acetone, and cyclohexanone. Examples of the acetate ester include ethyl acetate, methyl acetate, and butyl acetate. The hard coat layer coating composition may contain an alcohol solvent as the other solvent.

The coating amount of the hard coat layer coating composition is preferably 0.1 to 40 μm, more preferably 0.5 to 30 μm as a wet film thickness. The dry film thickness is preferably about 5 to 20 μm, preferably 7 to 12 μm.

The hard coat layer is a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die (extrusion) coater, a hard coat coating composition that forms a hard coat layer is applied using a known coating method such as an inkjet method, After application, the film can be dried, irradiated with actinic radiation (also referred to as UV curing treatment), and further subjected to heat treatment after UV curing as necessary. The heat treatment temperature after UV curing is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and particularly preferably 120 ° C. or higher. By performing the heat treatment after UV curing at such a high temperature, the mechanical strength (rubbing resistance, pencil hardness) of the hard coat layer becomes better.

<Functional layer>
In the hard coat film of this embodiment, functional layers such as a back coat layer, an antireflection layer and an antiglare layer can be provided in addition to the above hard coat layer.

(Back coat layer)
In the cellulose ester film of this embodiment, a back coat layer may be provided on the surface opposite to the side on which the hard coat layer is provided in order to prevent curling and blocking.

In terms of curling and blocking prevention, the back coat layer includes silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, indium oxide, Particles such as zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate can be added.

The particles contained in the backcoat layer are preferably 0.1 to 50% by mass with respect to the binder. When the back coat layer is provided, the increase in haze is preferably 0.5% or less, and particularly preferably 0.1% or less. As the binder, a cellulose ester resin is preferable. The coating composition for forming the backcoat layer preferably contains a solvent for alcohols, ketones and / or acetate ester sugars.

(Antireflection layer)
The hard coat film of the present embodiment can also be used as an antireflection film having an external light antireflection function by coating an antireflection layer on the hard coat layer.

The antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is composed of a low refractive index layer having a refractive index lower than that of the film substrate as a support, or a combination of a high refractive index layer having a refractive index higher than that of the support and a low refractive index layer. Is preferred. Particularly preferably, it is an antireflection layer composed of three or more refractive index layers, and three layers having different refractive indexes from the support side are divided into medium refractive index layers (high refractive index layers having a higher refractive index than the support). Are preferably laminated in the order of a layer having a lower refractive index) / a high refractive index layer / a low refractive index layer. Alternatively, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used.

As the layer structure of a film having an antireflection layer, the following structure is conceivable, but is not limited thereto.

Cellulose acetate film / hard coat layer / low refractive index layer Cellulose acetate film / hard coat layer / medium refractive index layer / low refractive index layer Cellulose acetate film / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index Layer Cellulose acetate film / hard coat layer / high refractive index layer (conductive layer) / low refractive index layer Cellulose acetate film / hard coat layer / antiglare layer / low refractive index layer

(Low refractive index layer)
The low refractive index layer preferably contains silica-based fine particles, and the refractive index is preferably in the range of 1.30 to 1.45 when measured at 23 ° C. and wavelength of 550 nm.

The film thickness of the low refractive index layer is preferably 5 nm to 0.5 μm, more preferably 10 nm to 0.3 μm, and most preferably 30 nm to 0.2 μm.

(High refractive index layer)
The refractive index of the high refractive index layer is preferably adjusted to a range of 1.4 to 2.2 by measuring at 23 ° C. and a wavelength of 550 nm. The thickness of the high refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm. The refractive index can be adjusted by adding metal oxide fine particles and the like. The metal oxide fine particles to be used preferably have a refractive index of 1.80 to 2.60, more preferably 1.85 to 2.50.

(Anti-glare layer)
On the hard coat layer, an antiglare layer can be provided as a functional layer. The antiglare layer reduces the visibility of the reflected image by blurring the outline of the image reflected on the film surface, so that the reflected image is reflected when using an image display device such as a liquid crystal display, an organic EL display, or a plasma display. It is a layer that keeps you from worrying. Specifically, the antiglare layer has an arithmetic average roughness Ra of 0.1 to 0.1 on the surface of the layer by adding fine particles or the like to the hard coat layer and pressing the mold to form protrusions on the surface. A layer adjusted to 1 μm is preferable.

(Adhesive layer)
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer (corresponding to the pressure-sensitive adhesive layer 30 in FIG. 1) used when bonding the touch panel to the display device is not particularly limited, and a known pressure-sensitive adhesive can be used. For example, an acrylic pressure-sensitive adhesive Silicone pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, and the like can be used, and acrylic pressure-sensitive adhesives that are relatively easy to control adhesive strength and storage elastic modulus are particularly preferable.

Acrylic adhesives include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, (meth)

acrylic

1 or 2 or more kinds of alkyl esters of 1 to 20 carbon atoms such as 2-ethylbutyl acid, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, and the alkyl acrylate Copolymerization with functional monomers such as (meth) acrylic acid, itaconic acid, maleic acid, maleic anhydride, 2-hydroxyethyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate that can be copolymerized with esters Combined with isocyanate crosslinker, epoxy crosslinker, aziridine crosslinker, metal chelate crosslink Obtained by reacting a crosslinking agent and the like.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 13 μm. When the thickness of the pressure-sensitive adhesive layer is 1 μm or more, sufficient adhesive strength can be obtained, and when the thickness is 13 μm or less, it is possible to suppress the protrusion of glue during punching or cutting, and high pencil hardness is maintained. . A preferable thickness of the pressure-sensitive adhesive layer is 3 to 12 μm.

As the storage elastic modulus of the pressure-sensitive adhesive layer, the storage elastic modulus at 0 ° C. is preferably 1.0 × 10 ⁶ to 1.0 × 10 ⁸ Pa. When the storage elastic modulus of the pressure-sensitive adhesive layer is 1.0 × 10 ⁶ Pa or more, sufficient punching processability, cutting processability and high pencil hardness are obtained, and when it is 1.0 × 10 ⁸ Pa or less, sufficient adhesiveness is obtained. Power is obtained. A preferable storage elastic modulus of the pressure-sensitive adhesive layer is 1.5 × 10 ⁶ to 1.0 × 10 ⁷ Pa.

Examples of the method of providing the pressure-sensitive adhesive layer on the film include a method of laminating the film on the pressure-sensitive adhesive layer prepared by applying the pressure-sensitive adhesive-containing composition to the release sheet and drying it. Examples of the method for applying the pressure-sensitive adhesive-containing composition include conventionally known methods such as bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, and curtain coating. Moreover, you may make it laminate | stack an adhesive layer by apply | coating the said adhesive containing composition directly on the surface of a film, and making it dry.

Although various release sheets can be used as the above release sheet, the release sheet is typically composed of a base sheet having peelability on the surface. Examples of the base sheet include films such as polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, and polycarbonate resin, films in which fillers such as fillers are blended with these films, and synthetic paper. Moreover, paper base materials, such as glassine paper, clay coat paper, and quality paper, are mentioned.

In order to give the surface of the base sheet peelability, a release agent such as a thermosetting silicone resin or an ultraviolet curable silicone resin may be attached to the surface by coating or the like. The coating amount of the release agent is preferably 0.03 to 3.0 g / m ² . The release sheet is laminated with the surface having the release agent in contact with the pressure-sensitive adhesive layer.

[Anti-scattering film]
The scattering prevention film 25 is provided on the electrode layer (electrode pattern 22) in order to prevent the glass substrate 21 from scattering due to an external impact or the like. In this embodiment, the scattering prevention film 25 is composed of a cellulose ester film having a thickness of 20 to 66 μm.

Examples of the cellulose ester resin that can be used for the scattering prevention film 25 include cellulose ester resins that can be used for the protective film (film substrate 4a) described above.

As such a cellulose ester film, a film having a retardation Ro in the in-plane direction of 0 nm to 10 nm can be preferably used. In this case, since there is little interference due to the phase difference in the in-plane direction, it is possible to improve the visibility when viewing the display panel 10 with the naked eye via the touch panel 20. When a film having a retardation Ro in the in-plane direction of 0 nm to 10 nm is used, a cellulose ester having a total acyl substitution degree of 2.6 or more is preferably used, and a cellulose acetate having a total acyl substitution degree of 2.6 or more (cellulose) Triacetate) is more preferably used.

Further, as the cellulose ester film of the scattering prevention film 25, a film having a retardation Ro in the in-plane direction of 30 nm to 200 nm is used, and the slow axis of the scattering prevention film is 10 to 80 with respect to the transmission axis of the polarizer 3. It is preferable that they are arranged in the direction of °. With such a configuration, the linearly polarized light transmitted through the polarizer 3 can be changed to elliptically polarized light or circularly polarized light, so that the visibility when viewing the display device 10 with polarized sunglasses can be improved. . In the case of a film having a retardation Ro of 30 nm to 200 nm, a cellulose ester having a total acyl substitution degree of less than 2.6 is preferably used, and cellulose acetate (cellulose diacetate) having a total acyl substitution degree of less than 2.6 is preferably used. More preferably used.

[Conductive layer]
The conductive layer (corresponding to the conductive layer 26 in FIG. 1) as an electromagnetic wave shielding layer formed on the scattering prevention film contains at least a conductive substance, and contains a binder, a photosensitive compound, and other components as necessary. It is desirable to contain.

[Conductive substance]
There is no restriction | limiting in particular as a structure of an electroconductive substance, Although it can select suitably according to the objective, It is preferable to contain the fiber and conductive polymer of any one of a solid structure and a hollow structure.

Here, solid structure fibers may be referred to as wires, and hollow structure fibers may be referred to as tubes.

Also, conductive fibers having an average minor axis length of 5 nm to 1,000 nm and an average major axis length of 1 μm to 100 μm may be referred to as “nanowires”.

In addition, a conductive fiber having an average minor axis length of 1 nm to 1,000 nm and an average major axis length of 0.1 μm to 1,000 μm and having a hollow structure may be referred to as “nanotube”.

The material of the conductive substance is not particularly limited as long as it has conductivity, and can be appropriately selected according to the purpose, but is preferably at least one of metal and carbon. Among these, the conductive fibers are preferably at least one of metal nanowires, metal nanotubes, and carbon nanotubes.

<Metal nanowires>
There is no restriction | limiting in particular as a material of metal nanowire, According to the objective, it can select suitably. For example, at least one metal selected from the group consisting of the fourth period, the fifth period, and the sixth period of the Long Periodic Table (IUPAC 1991) is preferred, and at least one kind selected from Group 2 to Group 14 is preferred. Metal is more preferable, and at least one metal selected from Group 2, Group 8, Group 9, Group 10, Group 11, Group 12, Group 13, and Group 14 is more preferable. It is particularly preferable to include it as a component.

Examples of the metal include copper, silver, gold, platinum, palladium, nickel, tin, cobalt, rhodium, iridium, iron, ruthenium, osmium, manganese, molybdenum, tungsten, niobium, tantel, titanium, bismuth, antimony, and lead. Or alloys thereof. Among these, silver and an alloy with silver are preferable in terms of excellent conductivity.

Examples of the metal used in the alloy with silver include platinum, osmium, palladium, iridium and the like. These may be used alone or in combination of two or more.

There is no restriction | limiting in particular as a shape of metal nanowire, According to the objective, it can select suitably. For example, it can take an arbitrary shape such as a columnar shape, a rectangular parallelepiped shape, or a columnar shape having a polygonal cross section. In applications where high transparency is required, a cylindrical shape or a cross-sectional shape with rounded polygonal corners is preferable. The cross-sectional shape of the metal nanowire can be examined by applying a metal nanowire aqueous dispersion on the substrate and observing the cross-section with a transmission electron microscope (TEM).

The average minor axis length (sometimes referred to as “average minor axis diameter” or “average diameter”) of the metal nanowires is preferably 1 nm to 50 nm. When the average minor axis length is less than 1 nm, the oxidation resistance deteriorates and the durability may deteriorate. When the average minor axis length exceeds 50 nm, scattering due to metal nanowires occurs and sufficient transparency is obtained. There are times when you can't. The average minor axis length is more preferably 10 nm to 40 nm, and further preferably 15 nm to 35 nm.

The average minor axis length of the metal nanowires was determined by observing 300 metal nanowires using a transmission electron microscope (TEM; manufactured by JEOL Ltd., JEM-2000FX) and calculating the average of the metal nanowires from the average value. Find the minor axis length. In addition, the shortest axis length when the short axis of the metal nanowire is not circular is the longest axis.

The average major axis length of the metal nanowire (sometimes referred to as “average length”) is preferably 1 μm to 40 μm. If the average major axis length is less than 1 μm, it may be difficult to form a dense network and sufficient conductivity may not be obtained. If it exceeds 40 μm, the metal nanowires are too long and manufactured. Sometimes entangled and agglomerates may occur during the manufacturing process. The average major axis length is more preferably 3 μm to 35 μm, and still more preferably 5 μm to 30 μm.

The average major axis length of the metal nanowire is, for example, observed with 300 metal nanowires using a transmission electron microscope (TEM; manufactured by JEOL Ltd., JEM-2000FX). Find the average major axis length. In addition, when the metal nanowire is bent, a circle having the arc as an arc is taken into consideration, and a value calculated from the radius and the curvature is defined as the major axis length.

Examples of the method for producing metal nanowires include, for example, JP 2009-215594 A, JP 2009-242880 A, JP 2009-299162 A, JP 2010-84173 A, and JP 2010-86714 A. The described method can be used. The method for producing the metal nanowire is not particularly limited and may be produced by any method. By reducing metal ions while heating in a solvent in which a halogen compound and a dispersion additive are dissolved as follows, It is preferable to manufacture.

<Metal nanotubes>
There is no restriction | limiting in particular as a material of a metal nanotube, What kind of metal may be sufficient, For example, the material of the above-mentioned metal nanowire etc. can be used.

The shape of the metal nanotube may be a single layer or a multilayer, but is preferably a single layer from the viewpoint of excellent conductivity and thermal conductivity.

The thickness of the metal nanotube (difference between the outer diameter and the inner diameter) is preferably 3 nm to 80 nm. When the thickness is less than 3 nm, the oxidation resistance may be deteriorated and the durability may be deteriorated. When the thickness is more than 80 nm, scattering due to the metal nanotube may occur. The thickness is more preferably 3 nm to 30 nm.

The average long axis length of the metal nanotube is preferably 1 μm to 40 μm, more preferably 3 μm to 35 μm, and still more preferably 5 μm to 30 μm.

The method for producing the metal nanotube is not particularly limited and may be appropriately selected depending on the purpose. For example, the method described in US Patent Application Publication No. 2005/0056118 and the like can be used.

<Carbon nanotube>
A carbon nanotube (CNT) is a substance in which a graphite-like carbon atomic surface (graphene sheet) is a single-layer or multilayer coaxial tube. Single-walled carbon nanotubes are called single-walled nanotubes (SWNT), multi-walled carbon nanotubes are called multi-walled nanotubes (MWNT), and in particular, double-walled carbon nanotubes are also called double-walled nanotubes (DWNT). In the conductive fiber used in the present embodiment, the carbon nanotube may be a single layer or a multilayer, but is preferably a single layer in terms of excellent conductivity and thermal conductivity.

The method for producing the carbon nanotube is not particularly limited and can be appropriately selected depending on the purpose. For example, catalytic hydrogen reduction of carbon dioxide, arc discharge method, laser evaporation method, thermal CVD method, plasma CVD method, vapor phase growth method, HiPco in which carbon monoxide is reacted with iron catalyst at high temperature and high pressure to grow in the vapor phase Known means such as a high-pressure carbon monoxide process can be used.

In addition, the carbon nanotubes obtained by these methods have been highly purified to remove residues such as by-products and catalytic metals by methods such as washing, centrifugation, filtration, oxidation, and chromatography. It is preferable at the point which can obtain a carbon nanotube.

The aspect ratio of the conductive fiber is preferably 10 or more. The aspect ratio generally means the ratio between the long side and the short side of the fibrous material (ratio of average major axis length / average minor axis length).

The aspect ratio measurement method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a method of measuring with an electron microscope.

When measuring the aspect ratio of the conductive fiber with an electron microscope, it is only necessary to confirm whether the aspect ratio of the conductive fiber is 10 or more with one field of view of the electron microscope. Moreover, the aspect ratio of the whole conductive fiber can be estimated by measuring the major axis length and the minor axis length of the conductive fiber separately.

When the conductive fiber is in a tube shape, the outer diameter of the tube is used as the diameter for calculating the aspect ratio.

The aspect ratio of the conductive fiber is not particularly limited as long as it is 10 or more, and can be appropriately selected according to the purpose, but is preferably 50 to 1,000,000. When the aspect ratio is less than 10, network formation with conductive fibers may not be performed, and sufficient conductivity may not be obtained. When the aspect ratio exceeds 1,000,000, the conductive fibers may be formed or in subsequent handling. Since the conductive fibers are entangled and aggregate before film formation, a stable liquid may not be obtained. The aspect ratio is more preferably 100 to 1,000,000.

The ratio (ratio) of the conductive fibers having an aspect ratio of 10 or more in the total conductive composition is preferably 50% or more by volume ratio. If the ratio is less than 50%, the conductive material that contributes to conductivity may decrease and conductivity may decrease. At the same time, a dense network cannot be formed, resulting in voltage concentration and durability. May fall. In addition, particles having a shape other than conductive fibers do not contribute greatly to conductivity and have absorption, which is not preferable. Especially in the case of metal, when plasmon absorption such as a sphere is strong, the transparency is deteriorated. It may end up. The ratio is more preferably 60% or more, and particularly preferably 75% or more.

Here, the ratio is, for example, when the conductive fiber is silver nanowire, the silver nanowire aqueous dispersion is filtered to separate the silver nanowire and the other particles, and the ICP emission analysis By measuring the amount of silver remaining on the filter paper and the amount of silver transmitted through the filter paper using an apparatus, the ratio of conductive fibers can be determined. By observing the conductive fibers remaining on the filter paper with a TEM, observing the short axis lengths of 300 conductive fibers and examining their distribution, the short axis length is 200 nm or less and the long axis length is It confirms that it is an electroconductive fiber whose length is 1 micrometer or more. Note that the filter paper measures the longest axis of particles other than the conductive fibers of the above size, and passes particles having a length not less than twice the longest axis and not more than the shortest length of the long axis of the conductive fibers. It is preferable to use one.

Here, the average minor axis length and the average major axis length of the conductive fiber can be obtained by observing a TEM image or an optical microscope image using, for example, a transmission electron microscope (TEM) or an optical microscope. it can. In the present embodiment, the average minor axis length and the average major axis length of the conductive fibers are obtained by observing 300 conductive fibers with a transmission electron microscope (TEM) and calculating the average value.

<Binder>
The binder for immobilizing the conductive fiber is an organic polymer, and promotes at least one alkali solubility in a molecule (preferably a molecule having an acrylic copolymer as a main chain). It can be appropriately selected from alkali-soluble resins having a group (for example, carboxyl group, phosphoric acid group, sulfonic acid group, etc.).

Among these, those that are soluble in an organic solvent and that can be developed with a weak alkaline aqueous solution are preferable, and those that have an acid-dissociable group and become alkali-soluble when the acid-dissociable group is dissociated by the action of an acid. Particularly preferred. In addition, an acid dissociable group represents the functional group which can dissociate in presence of an acid.

For the production of the binder, for example, a known radical polymerization method can be applied. Polymerization conditions such as temperature, pressure, type and amount of radical initiator, type of solvent, etc. when producing an alkali-soluble resin by the above radical polymerization method can be easily set by those skilled in the art, and the conditions are determined experimentally. Can be determined.

As the linear organic polymer, a polymer having a carboxylic acid in the side chain (photosensitive resin having an acidic group) is preferable.

Examples of the polymer having a carboxylic acid in the side chain include, for example, JP-A-59-44615, JP-B-54-34327, JP-B-58-12777, JP-B-54-25957, JP-A-59-53836, A methacrylic acid copolymer, an acrylic acid copolymer, an itaconic acid copolymer, a crotonic acid copolymer, a maleic acid copolymer, and a partial esterification as described in each publication of Japanese Utility Model Publication No. 59-71048. A maleic acid copolymer, etc., an acidic cellulose derivative having a carboxylic acid in the side chain, an acid anhydride added to a polymer having a hydroxyl group, and a polymer weight having a (meth) acryloyl group in the side chain Coalescence is also preferred.

Among these, benzyl (meth) acrylate / (meth) acrylic acid copolymers and multi-component copolymers composed of benzyl (meth) acrylate / (meth) acrylic acid / other monomers are particularly preferable.

Furthermore, a high molecular polymer having a (meth) acryloyl group in the side chain and a multi-component copolymer composed of (meth) acrylic acid / glycidyl (meth) acrylate / other monomers are also useful. The polymer can be used by mixing in an arbitrary amount.

In addition to the above, 2-hydroxypropyl (meth) acrylate / polystyrene macromonomer / benzyl methacrylate / methacrylic acid copolymer, 2-hydroxy-3-phenoxypropyl acrylate / polymethyl described in JP-A-7-140654 Methacrylate macromonomer / benzyl methacrylate / methacrylic acid copolymer, 2-hydroxyethyl methacrylate / polystyrene macromonomer / methyl methacrylate / methacrylic acid copolymer, 2-hydroxyethyl methacrylate / polystyrene macromonomer / benzyl methacrylate / methacrylic acid copolymer Coalescence, etc.

<Conductive polymer>
As the conductive polymer, for example, polyethylenedioxythiophene (PEDOT: PSS (Poly (3,4-ethylenedioxythiophene): Poly (styrenesulfonate)) containing polystyrenesulfonic acid can be used.

〔Example〕
Hereinafter, specific examples of the present invention will be described as examples. For comparison with the present invention, comparative examples will also be described. The present invention is not limited to the following examples. In the following description, “parts” or “%” indicates “parts by mass” or “mass%” unless otherwise specified.

<Production of touch panel module>
First, an ITO film having a thickness of 20 nm was formed on a (strengthened) glass substrate by a sputtering method, and this was etched to form a first electrode pattern extending in the X direction. Next, an interlayer insulating film made of SiO ₂ having a thickness of 200 nm was formed on the first electrode pattern by a sputtering method. Next, Ag paste was applied to the first electrode pattern and sintered, and the first electrode pattern and the control circuit were connected via lead wires.

Next, the conductive film was bonded onto the first electrode pattern (on the interlayer insulating film) via an adhesive layer to produce a touch panel module. At this time, an acrylic pressure-sensitive adhesive was used as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer. Hereinafter, production of the conductive film will be described.

(Preparation of conductive film)
<Preparation of anti-scattering film>
(Preparation of cellulose ester film A-1)
<Cellulose ester resin>
The cellulose ester resin CE-1 is as follows.
CE-1: cellulose triacetate (acetyl group substitution degree: 2.91, weight average molecular weight Mw: 300,000)

<Fine particle dispersion 1>
Silica fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.)
11 parts by mass Ethanol 89 parts by mass The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

<Fine particle addition liquid 1>
The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.
99 parts by mass of methylene chloride 5 parts by mass of fine particle dispersion 1

<Main dope A>
A main dope A having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Next, cellulose acetate was added to the pressurized dissolution tank containing the solvent while stirring. This was completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope A was prepared by filtration using 244.
Methylene chloride 340 parts by mass Ethanol 64 parts by mass CE-1 (cellulose triacetate) 100 parts by mass Polyester compound 6 parts by mass Sugar ester compound 6 parts by mass Particulate additive solution 1 1 part by mass A dope was prepared. Then, using an endless belt casting apparatus, the dope was cast uniformly on a stainless steel belt support at a temperature of 33 ° C. and a width of 1500 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

Next, the solvent was evaporated on the stainless steel belt support until the amount of residual solvent in the cast (cast) film became 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.

The peeled cellulose ester film was stretched 10% in the width direction using a tenter while applying heat at 160 ° C. The residual solvent at the start of stretching was 15%. Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m. After drying, the film was slit to a width of 1.5 m, a knurling process with a width of 10 mm and a height of 10 μm was applied to both ends of the film, and wound into a roll to obtain a cellulose ester film A-1 having a dry film thickness of 40 μm. The winding length was 5200 m.

In the cellulose ester film A-1, the retardation in the in-plane direction (retardation Ro) was 2 nm. The retardation Ro was measured using an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments). Incidentally, the retardation Ro (nm) in the in-plane direction of the film is obtained by the following equation.
Ro = (nx−ny) × d
Where d is the thickness (nm) of the film, nx is the refractive index in the slow axis direction, and ny is the refractive index in the direction perpendicular to the slow axis in the film plane.

(Production of cellulose ester films A-2 to A-5)
Cellulose ester films A-2 to A-5 were produced in the same manner as the cellulose ester film A-1, except that the film thickness and retardation Ro were changed as shown in Table 1.

(Preparation of PC film A-6)
In a reactor equipped with a thermometer, a stirrer, and a reflux condenser, 152400 parts of ion-exchanged water and 84320 parts of 25% aqueous sodium hydroxide solution were added, and 9,9-bis (4-hydroxy-3 having a purity of 99.8% by HPLC analysis. -Methylphenyl) fluorene (hereinafter abbreviated as “biscresol fluorene”) 34848 parts, 2,2-bis (4-hydroxyphenyl) propane 9008 parts (hereinafter abbreviated as “bisphenol A”) and After dissolving 88 parts of hydrosulfite, 178400 parts of methylene chloride was added and stirred. Then, 18248 parts of phosgene was blown in at a temperature of 15 to 25 ° C. over 60 minutes. After the completion of phosgene blowing, a solution obtained by dissolving 177.8 parts of p-tert-butylphenol in 2640 parts of methylene chloride and 10560 parts of a 25% aqueous sodium hydroxide solution were added. After emulsification, 32 parts of triethylamine was added and the mixture was added at 28 to 33 ° C. The reaction was terminated by stirring for a period of time.

After completion of the reaction, the product is diluted with methylene chloride, washed with water, acidified with hydrochloric acid and washed with water. When the conductivity of the aqueous phase is almost the same as that of ion-exchanged water, the methylene chloride phase is concentrated and dehydrated. A solution having a polycarbonate concentration of 20% was obtained. The polycarbonate (copolymer A) obtained by removing the solvent from this solution had a molar ratio of biscresol fluorene to bisphenol A of 70:30 (polymer yield 97%). This polymer had an intrinsic viscosity of 0.674 and a glass transition temperature Tg of 226 ° C.

25 parts by mass of the polycarbonate was dissolved while stirring at 25 ° C. with respect to 75 parts by mass of a mixed solvent of methylene chloride and ethanol containing 4 parts by mass of ethanol to obtain a transparent and viscous dope. The dope was poured on a 100 m stainless steel belt having a dew point controlled to 12 ° C. or less by blowing dry air and peeled off. The residual solvent concentration at that time was 35%. Due to the good releasability and low charge, the visual observation showed no peeling step or peeling streaks on the film surface. Thereafter, when the residual solvent concentration was 2%, the film was stretched twice in the width direction and then dried while maintaining the width. Thereafter, drying was performed until the residual solvent concentration became 1% or less to obtain PC film A-6 having a width of 1.5 m and a dry film thickness of 80 μm. The winding length was 5200 m. Also. The retardation of PC film A-6 was measured by the same measurement method as described above, and as a result, retardation Ro was 500 nm.

(Preparation of COP film A-7)
<Synthesis of polymer resin having alicyclic structure>
Under an ethylene atmosphere, toluene and a phenylnorbornene-toluene solution were placed in an autoclave having a volume of 1.6 l so that the phenylnorbornene concentration was 20 mol / l and the total liquid volume was 640 ml. Next, 5.88 mmol of methylaluminoxane (manufactured by Albemarle, MAO 20% toluene solution) and 1.5 μmol of methylene (cyclopentadienyl) (tetramethylcyclopentadienyl) zirconium dichloride were added on the basis of Al, and ethylene was introduced. Then, the reaction was carried out at 80 ° C. for 60 minutes while maintaining the pressure at 0.2 MPa.

After completion of the reaction, ethylene was depressurized while allowing to cool, and the system was replaced with nitrogen. Thereafter, 3.0 g of silica (manufactured by Fuji Silysia Co., grade: G-3 particle size: 50 μm) with the adsorbed water content adjusted to 10% by mass was added and reacted for 1 hour. The reaction solution was placed in a pressure filter (Advantech Toyo Co., Ltd., model KST-90-UH) set with filter paper (5C, 90 mm) and Celite (Wako Pure Chemical Industries, Ltd.), and pressure filtered with nitrogen. The polymerization solution was recovered. The polymerization solution was dropped dropwise in 5 times amount of acetone and deposited to obtain a polymer resin COP1 having an alicyclic structure. COP1 had a weight average molecular weight of 142,000 and a glass transition temperature of 140 ° C.

The polymer resin COP1 having an alicyclic structure synthesized above is dried for 2 hours at 70 ° C. using a hot air dryer in which air is circulated to remove moisture, and then resin melt kneaded with a 65 mmφ screw A COP film having a film thickness of 100 μm was extruded using a T-die film melt extrusion molding machine (T-die width 500 mm) having a machine under molding conditions of a molten resin temperature of 240 ° C. and a T-die temperature of 240 ° C.

Next, the peeled COP film was stretched 90% in the width direction using a tenter while applying heat at 200 ° C. Next, drying was completed while the drying zone was conveyed by a number of rollers. The drying temperature was 130 ° C. and the transport tension was 100 N / m. After drying, it was slit into a width of 1.5 m, a knurling process having a width of 10 mm and a height of 10 μm was applied to both ends of the film, and wound into a roll to obtain a COP film A-7 having a dry film thickness of 100 μm. The winding length was 5000 m. The retardation of the COP film A-7 was measured by the same measurement method as described above, and as a result, the retardation Ro was 0 nm.

(Preparation of PET film A-8)
<Polyester A>
To 100 parts by mass of dimethyl terephthalate and 64 parts by mass of ethylene glycol, 0.1 part by mass of calcium acetate hydrate was added, and transesterification was performed by a conventional method. The obtained product was mixed with ethylene glycol solution of 5-sodium sulfodi (β-hydroxyethyl) isophthalic acid (concentration 35% by mass) (7 mol% / total dicarboxylic acid component), polyethylene glycol (number average molecular weight 3000). 5.8 parts by mass (5% by mass / generated polyester), 0.05 parts by mass of antimony trioxide, and 0.13 parts by mass of trimethyl phosphate. Next, the temperature was gradually raised and the pressure was reduced, and polymerization was performed at 280 ° C. and 40 Pa to obtain polyester A. And as a result of calculating | requiring the intrinsic viscosity of the polyester A according to the method shown below, intrinsic viscosity was 0.50 dl / g.

The intrinsic viscosity was calculated by the following procedure using an Ubbelohde viscometer. Using a mixed solvent of phenol and 1,1,2,2-tetrachloroethane having a mass ratio of about 55:45 (adjusted to a flow time of 42.0 ± 0.1 seconds), the sample was dissolved to a concentration of 0.2 , 0.6, 1.0 (g / dl) solution (temperature 20 ° C.). Using an Ubbelohde viscometer, the specific viscosity (ηsp) at each concentration (C) was determined, and the equation [ηsp / C] was extrapolated to a concentration of zero (C → 0) to determine the intrinsic viscosity [η]. The unit of intrinsic viscosity [η] is dl / g.

The polyester A pellets were vacuum-dried at 150 ° C. for 8 hours, melt-extruded at 285 ° C. using an extruder, closely adhered to a 30 ° C. cooling drum while electrostatically applied, and cooled and solidified to obtain an unstretched sheet. It was. This unstretched sheet was stretched 2.0 times in the longitudinal direction at 90 ° C. using a roller-type longitudinal stretching machine. The temperature difference between the front and back surfaces was within 5 ° C.

The obtained uniaxially stretched film was stretched 1.2 times in the transverse direction at 100 ° C. using a tenter-type transverse stretching machine. Next, heat treatment was performed at 70 ° C. for 2 seconds, heat-fixed at 150 ° C. for the first heat setting zone for 10 seconds, heat-setting at the second heat setting zone at 180 ° C. for 15 seconds, and then 2% in the width direction at 160 ° C. The PET film A-8 having a width of 1.5 m and a dry film thickness of 100 μm was produced after being relaxed and wound up. The winding length was 5000 m. The retardation of the PET film A-8 was measured by the same measurement method as described above. As a result, the retardation Ro was 3000 nm.

The cellulose ester film, COP film, PC film, and PET film produced above were used as the anti-scattering film for the conductive film.

(Preparation of hard coat film)
On the cellulose ester film A-5, PC film A-6, and PET film A-8 produced above, the hard coat layer composition is filtered through a polypropylene filter having a pore size of 0.4 μm using a micro gravure coater. Applied. Then, after drying at a constant rate drying zone temperature of 95 ° C. and a reduced rate drying zone temperature of 95 ° C., an ultraviolet lamp is used, the illuminance of the irradiated part is 100 mW / cm ² , and the irradiation amount is 0.1 J / cm ^2. Was cured to form a hard coat layer having a dry film thickness of 3 μm. And the film after formation was wound up and it was set as the roll-shaped hard coat film. The hard coat layer was produced only when an ITO conductive film described later was formed as the conductive layer.

(Formation of conductive layer)
<Silver nanowires>
Silver nanowires were obtained by the method disclosed in Example 1 (synthesis of silver nanowires) in JP-T-2009-505358. That is, silver nanowires were synthesized by reduction of silver sulfate dissolved in ethylene glycol in the presence of polyvinylpyrrolidone (PVP). Note that the method of reducing metal ions and precipitating nano-sized metal particles by the reducing power of polyol (polyhydric alcohol) is also called a polyol method.

Next, a silver nanowire-dispersed coating liquid was obtained by the method disclosed in Example 8 (nanowire dispersion) of JP-T 2009-505358. That is, about 0.08% wt. HPMC (hydroxypropyl methylcellulose), about 0.36% wt. Silver nanowire, about 0.005% wt. Zonyl® FSO-100, and about 99.555% wt. Were mixed to obtain a silver nanowire-dispersed coating solution. This silver nanowire dispersion coating liquid was applied onto a cellulose ester film using a bar coater manufactured by Matsuo Sangyo Co., Ltd. and dried at 120 ° C. for 2 minutes to provide a silver nanowire coating film.

<Copper nanowire>
Copper nanowires were produced by the method described in JP-A-2002-266007. That is, 0.1 mmol of double-headed peptide lipid is placed in a sample bottle, and 100 ml of distilled water containing 8.0 mg (0.20 mmol) of double equivalent sodium hydroxide is added thereto, followed by ultrasonic irradiation (bath type). Thus, the double-headed peptide lipid was dissolved. This aqueous solution was kept at room temperature while stirring vigorously on a hot stirrer, and 1 ml of 0.1 mol / liter copper (II) acetate was added thereto. As a result, the solution gradually became cloudy and a blue colloidal dispersion was formed.

Next, this blue colloidal dispersion was stirred at room temperature in the air, and 100 ml (0.5 mmol) of 5 mmol / liter sodium borohydride aqueous solution was added. The solution immediately turned dark brown and a dark gray flocculent precipitate formed after approximately 6 hours. The cotton-like precipitate was observed with a transmission electron microscope, and the spherical structure having a diameter of several tens to several hundreds of nanometers and the formation of copper nanowires were confirmed. From the transmission electron micrograph, it was found that the average diameter of the copper nanowires was 10 to 20 nm and the average length was 1 to 10 μm or more.

<ITO conductive film>
Using an indium tin oxide target having a composition of In ₂ O ₂ / SnO ₂ = 90/10, with a vacuum of 10 ⁻⁴ Torr and introducing a mixed gas of argon / oxygen, a sputtering method is performed on the hard coat film. Further, an ITO conductive thin film having a thickness of 250 nm was provided.

<Preparation of polarizing plate>
Next, production of a polarizing plate for a display panel will be described. The polarizing plate is produced by bonding a surface protective film to one surface of a polarizing film as a polarizer and bonding a back surface protective film to the other surface. First, preparation of a surface protective film and a back surface protective film will be described.

(Creation of surface protective film)
<Production of cellulose ester film>
Cellulose ester films B-1 to B-5 and B-7 to B-8 were prepared in the same manner as the cellulose ester film A-1, except that the film thickness and retardation Ro were changed as shown in Table 1. did.

<Production of acrylic film>
Acrylic film B-6 was produced by the following method. The acrylic film B-6 did not contain a plasticizer.

(Preparation of acrylic film)
The following acrylic resin containing a lactone ring unit was prepared. That is, it was synthesized from 7500 g of methyl methacrylate and 2500 g of methyl 2- (hydroxymethyl) acrylate according to Production Example 1 of paragraphs [0222] to [0224] of JP-A-2008-9378, and the lactonization rate was 98%. = 134 ° C. acrylic resin was obtained.

(Acrylic film formation)
The prepared acrylic resin was dried with a vacuum dryer at 90 ° C. to a water content of 0.03% or less, and then a stabilizer (Irganox 1010 (manufactured by Ciba-Gigi Co., Ltd.)) was added in an amount of 0.3% by weight. In a nitrogen stream at 230 ° C., a biaxial kneading extruder with a vent was used to form an extruded strand in water and then cut to obtain pellets having a diameter of 3 mm and a length of 5 mm.

These pellets are dried in a vacuum dryer at 90 ° C. to a water content of 0.03% or less, and then kneaded at a supply unit 210 ° C., a compression unit 230 ° C., and a weighing unit 230 ° C. using a single-screw kneading extruder. And extruded from a hanger coat die. At this time, a 300-mesh screen filter, a gear pump, and a leaf disk filter with a filtration accuracy of 7 μm were arranged in this order between the extruder and the die, and these were connected by a melt pipe. Furthermore, a static mixer was installed in the melt pipe immediately before the die.

After this, the melt (molten resin) was extruded onto a triple cast roll. At this time, the touch roll was brought into contact with the most upstream cast roll (chill roll). The touch roll described in Example 1 of JP-A No. 11-235747 (the one described as a double holding roll was used, but the thickness of the thin metal outer cylinder was 2 mm) was used. The temperature of the triple cast rolls including the chill rolls was, in order from the upstream, touch roll temperature + 3 ° C., touch roll temperature −2 ° C., and touch roll temperature −7 ° C.

Then, after trimming both ends (5 cm each of the total width) immediately before winding, a thickness increasing process (knurling) with a width of 10 mm and a height of 20 μm was applied to both ends. Further, the film-forming width was 1.5 m, and the film was wound up 3000 m at a film-forming speed of 30 m / min. The thickness of the unstretched film after film formation was 40 μm.

(Creation of back surface protection film)
<Production of acrylic film>
Acrylic films C-1, C-4, and C-8 were produced in the same manner as the acrylic film B-6 except that the film thickness was changed as shown in Table 1.

<Production of COP film>
COP films C-2, C-3, C-6, and C-7 were produced in the same manner as COP film A-7 except that the film thickness was changed as shown in Table 1.

<Production of cellulose ester film>
A cellulose ester film C-5 was produced in the same manner as the cellulose ester film A-1, except that the film thickness and retardation Ro were changed as shown in Table 1.

(Production of polarizer)
100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400 was impregnated with 10 parts by mass of glycerin and 170 parts by mass of water. The film was melt-extruded from a T die onto a metal roll to form a film. Then, it dried and heat-processed and obtained the PVA film.

The obtained PVA film had an average thickness of 25 μm, a moisture content of 4.4%, and a film width of 3 m. Next, the obtained PVA film was continuously processed in the order of pre-swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to produce a polarizing film as a polarizer. That is, the PVA film was immersed in water at a temperature of 30 ° C. for 30 seconds to be pre-swelled, and immersed in an aqueous solution having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter at a temperature of 35 ° C. for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in a 50% aqueous solution with a boric acid concentration of 4% under a tension of 700 N / m. The potassium iodide concentration was 40 g / liter, and the boric acid concentration was 40 g / liter. Then, it was immersed in an aqueous solution having a zinc chloride concentration of 10 g / liter and a temperature of 30 ° C. for 5 minutes for fixing. Thereafter, the PVA film was taken out, dried with hot air at a temperature of 40 ° C., and further heat-treated at a temperature of 100 ° C. for 5 minutes. The obtained polarizing film had an average thickness of 13 μm, a polarizing performance of 43.0% transmittance, a polarization degree of 99.5%, and a dichroic ratio of 40.1.

(UV adhesion of film to polarizer)
A surface protective film and a back surface protective film are overlapped by a nip roll on both surfaces of a polyvinyl alcohol film (PVA film) having a thickness of 25 μm adsorbed and oriented with an epoxy resin composition as an ultraviolet curable adhesive. It was.

Next, the polarizing plate was irradiated with ultraviolet rays from two EHAN1700NAL high-pressure mercury lamps, which are ultraviolet lamps provided in an ultraviolet irradiation device (manufactured by GS-YUSASA), and the above adhesive was cured. At this time, while the surface of the polarizing plate on the surface protective film side is in close contact with the outer peripheral surface of the cooling roll at 23 ° C., the polarizing plate is polarized at a line speed of 11 m / min under a tension of 600 N in the longitudinal direction in the irradiated ultraviolet light. Was passed. At that time, the cumulative amount of ultraviolet light was 110 mJ / cm ² . The cumulative amount of ultraviolet light was measured based on irradiation in the UVB region having a wavelength range of 280 to 320 nm.

<Assembly of display device with touch panel>
The electrode layer side of the touch panel and the polarizing plate side of the liquid crystal display device were bonded together via an adhesive layer to constitute a liquid crystal display device with a touch panel.

More specifically, SVR1240 manufactured by Sony Chemical & Information Device Co. is applied as an adhesive to the surface of the protective film of the polarizing plate of the liquid crystal display device, and the liquid crystal display device and the touch panel are applied via the applied adhesive. Were pasted together. And both ultraviolet rays were irradiated to some adhesives, and both were temporarily fixed. Then, after inspecting for bubbles at the interface, the entire pressure-sensitive adhesive was completely cured by irradiation with ultraviolet rays.

Table 1 shows combinations of the conductive film, the surface protective film, and the back surface protective film in the liquid crystal display devices with touch panels according to Examples 1 to 4 and Comparative Examples 1 to 6.

<Evaluation of display device with touch panel>
(1) Evaluation of display unevenness The produced display device with a touch panel continued to display black for 120 hours in an environment of 60 ° C. and 90%, and the display state at that time was observed. The evaluation criteria at this time are as follows.
○: Neither the glare nor the white spotted pattern is generated.
(Triangle | delta): The nonuniformity of the white blank pattern generate | occur | produced.
X: Surface glare occurred.

(2) Evaluation of PVA orientation Contrast evaluation was performed about the produced display apparatus with a touch panel using the viewing angle characteristic measuring apparatus EZContrast (made by ELDIM). The evaluation criteria at this time are as follows.
○: Contrast is 100%.
Δ: Contrast reduction amount is less than 5%.
X: Contrast reduction amount is 5% or more.

(3) About Polarizer Degradation The prepared display device with a touch panel was allowed to stand in an environment of 60 ° C. and 90% for 500 hours, and then the state of black display was observed. The evaluation criteria at this time are as follows.
○: The display is black (not reddish).
Δ: Slightly reddish
X: The display is reddish.

[Evaluation results]
Table 2 shows the evaluation results of Examples 1 to 4 and Comparative Examples 1 to 6.

In Comparative Example 1 in which the back surface protective film of the polarizing plate contains cellulose ester, white display unevenness occurs during black display, whereas Examples 1 to 4 in which the back surface protective film contains COP or PMMA, Comparative Example In 2 to 6, display unevenness does not occur. This, COP and PMMA is less moisture permeability 200g ^/ m 2 ^/ 24h, it is possible to suppress the permeation of moisture as compared to a cellulose ester (moisture permeability 800g ^/ m 2 ^/ 24h or higher), the backside protective film It is considered that the phase difference (retardation Ro) is prevented from fluctuating due to the moisture, and white spots are not generated even during black display.

Moreover, even if the surface protection film contains the plasticizer in Comparative Example 2 and the surface protection film contains the plasticizer, the plasticizer is unevenly distributed on the polarizer side (less unevenly distributed on the touch panel side). In Comparative Example 6, a decrease in contrast occurs due to disorder in the orientation of the polarizer. On the other hand, in Examples 1 to 4 and Comparative Examples 1 and 3 to 5 in which the plasticizer contained in the surface protective film is unevenly distributed on the polarizer side, the contrast is not lowered due to disorder of the orientation of the polarizer. This is because the curing shrinkage of the adhesive at the time of UV adhesion of the surface protective film to the polarizer is suppressed by the surface with less plasticizer (the harder surface) in the surface protective film (cellulose ester film). This is thought to be because the disorder of the orientation of the film is suppressed.

In Comparative Examples 2 to 5, in which at least one of the conductive film scattering prevention film and the polarizing plate surface protective film is an optical film (PC, PMMA, COP, PET) having high moisture permeability, the polarizer is deteriorated. In Examples 1 to 4 and Comparative Examples 1 and 6 in which both the scattering prevention film and the surface protection film contain cellulose ester films having high moisture absorption and moisture permeability, the deterioration of the polarizer is small. This is because the moisture of the conductive layer and the polarizer (PVA) formed by aqueous coating is trapped by both the cellulose ester films, thereby preventing the polarizer from being deteriorated by the moisture. Conceivable. In particular, since the cellulose ester film of the surface protective film is as thin as 15 to 30 μm, it is easy for water to escape from the polarizer to the anti-scattering film through the surface protective film, and the polarizer is surely deteriorated by moisture. It is thought that it is suppressed to.

As described above, according to the configurations of Examples 1 to 4, display unevenness due to phase difference fluctuations of the back surface protective film, disorder of PVA orientation (contrast reduction) due to curing shrinkage during UV irradiation, and deterioration of the polarizer due to moisture are all caused. It can be said that it can be suppressed.

Separately from the above embodiment, touch panel A in which one electrode layer is formed on a glass substrate, and touch panel B in which two electrode layers (each electrode pattern in the X direction and Y direction) are formed on the glass substrate; In this case, the glass substrate was cut and the yield due to the disconnection of the electrode layer was examined. As a result, the yield of the touch panel A was better because the number of electrode layers was smaller (the occurrence rate of defective products due to the disconnection of the electrode layer was higher). It was found that touch panel productivity is high.

In the embodiment, a liquid crystal display panel (LCD) is used as the display panel, but it is considered that the same result can be obtained even when an OLED is used. That is, the display panel may be an LCD or an OLED. Moreover, when using OLED, the back surface protective film located in the OLED side with respect to a polarizer may be comprised with a quarter wavelength plate. Furthermore, the TFT substrate of the OLED may be composed of a resin substrate such as a film.

The present invention can be used for a display device with a touch panel in which a touch panel having an electrode layer on a glass substrate and a display device having a polarizing plate on a display panel are bonded together via an adhesive layer.

DESCRIPTION OF SYMBOLS 1 Display panel 2 Polarizing plate 3 Polarizer 4 Film 4a Film base material (surface protection film, cellulose ester film)
4b Hard coat layer 5 Film (back surface protective film)
DESCRIPTION OF SYMBOLS 10 Display apparatus 20 Touch panel 21 Glass substrate 22 Electrode pattern (electrode layer)
24 conductive film 25 scattering prevention film 26 conductive layer 30 pressure-sensitive adhesive layer

Claims

A display device with a touch panel in which the electrode layer side of a touch panel having an electrode layer on a glass substrate and the polarizing plate side of a display device having a polarizing plate on a display panel are bonded via an adhesive layer. ,
The electrode layer of the touch panel is composed of one layer, and a conductive film is bonded on the electrode layer,
The conductive film is made of a cellulose ester film and is formed by a water-based coating of a conductive material on the side opposite to the electrode layer with respect to the scattering prevention film for preventing the glass substrate from scattering. And a conductive layer
The polarizing plate includes a polarizer, a surface protective film bonded to the touch panel side of the polarizer via an ultraviolet curable adhesive, and an ultraviolet curable adhesive on the display panel side of the polarizer. With a back surface protective film bonded through
The back surface protective film is a following optical film moisture permeability 200g / m 2 / 24h,
The surface protective film is a cellulose ester film having a plasticizer and having a thickness of 15 to 30 μm, and the polarizing film passes through a surface opposite to the side where the plasticizer is unevenly distributed in the thickness direction of the film. A display device with a touch panel, which is bonded to a child.
The display device with a touch panel according to claim 1, wherein the polarizing plate further includes a hard coat layer on a side opposite to the polarizer with respect to the surface protective film.
The display device with a touch panel according to claim 1 or 2, wherein the conductive material is a conductive fiber.
The display device with a touch panel according to claim 3, wherein the conductive fiber is a metal nanowire.
The display device with a touch panel according to any one of claims 1 to 4, wherein the optical film of the back surface protective film is a film made of a resin selected from acrylic, cyclic polyolefin, and polycarbonate.