JP5954427B2 - Display device with touch panel - Google Patents

Description

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

  In recent years, as various electronic devices such as a mobile phone, a portable terminal, and a personal computer have become highly functional and diversified, a touch panel is used as one of input means to these electronic devices. The touch panel has optical transparency, and when it is bonded to, for example, a liquid crystal display device, the touch panel is mounted on a polarizing plate of the liquid crystal display device via an adhesive.

  Conventionally, a touch panel mounted on the surface of an information display unit of a mobile terminal is light transmissive in order to make the information displayed on the information display unit easier to see and to prevent damage 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.

  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 capacitance changes between the X electrode pattern and the Y electrode pattern, so that the change in capacitance is detected via the X electrode pattern and the Y electrode pattern. Thus, the pressing position can be specified.

  In a capacitance type touch panel, it is necessary to accurately detect a change in capacitance, and for that purpose, it is necessary to block electrical noise from peripheral components. For example, by providing a shield layer between the touch panel and the display panel, it is possible to block electrical noise from the display panel, that is, noise generated when the TFT (Thin Film Transistor) of the display panel is turned on / off. it can. At this time, the material of the shield layer is required to be transparent and conductive, and ITO which is the same material as the electrode of the touch panel can be used. The ITO film of the shield layer does not need to be patterned and may be formed on the entire surface of the substrate.

  However, the ITO film has a relatively high b * value in the L * a * b * color system and is easily yellowish. For this reason, if an ITO film is used for the shield layer in addition to the two-layer electrode, the display device equipped with the capacitive touch panel includes a total of three ITO films, resulting in a more yellowish color. The optical characteristics will be deteriorated. In addition, since an expensive vacuum sputtering apparatus is required to form the ITO film, further improvement in cost and productivity is required.

  Therefore, in Patent Document 1, the shield layer between the touch panel and the display panel is made of a conductive polymer (for example, polyethylene dioxythiophene). Many conductive polymers have a negative b * value and are bluish, which is effective in preventing the touch panel from becoming yellowish and can provide a touch panel with good optical properties. . In addition, the conductive polymer can be dispersed mainly in a liquid, so it can be applied wet without the need for an expensive vacuum device required for ITO film formation, improving productivity, and cost. It is possible to go down.

  Further, in Patent Document 2, the electrode structure in the touch panel is devised so that two types of electrodes and a shield layer are constituted by a total of two layers. Further, in Patent Document 3, a shield layer is formed using silver nanowires instead of ITO as a transparent conductive material. In these configurations, since the number of ITO films in the display device with a touch panel is two, it is considered that the deterioration of the optical characteristics of the touch panel can be suppressed as compared with the three-layer structure.

JP 2012-68760 A (refer to claim 1, paragraph [0011], FIG. 1 etc.) JP 2010-44453 A (refer to claim 1, paragraph [0020], FIG. 1, FIG. 2, etc.) JP 2012-8255 A (refer to claims 1, 12, 17, paragraphs [0026] to [0031], FIG. 1, FIG. 3, etc.)

  By the way, when a shield layer is comprised with silver nanowire, a shield layer is formed by apply | coating the coating liquid which disperse | distributed silver nanowire on a base material, and making it dry, for example. A display layer with a touch panel can be configured by forming a shield layer on the polarizing plate by water-based application of such silver nanowires and bonding the shield layer and the touch panel via an adhesive layer.

  At this time, if the glass substrate (cover glass) is located on the outermost layer of the touch panel (the side opposite to the display device), the moisture in the shield layer generated by the aqueous coating escapes to the outside of the touch panel through the glass substrate. Stays in the shield layer. As a result, the shielding property of the shield layer is lowered by the moisture, and noise from the display panel cannot be blocked, and the touch panel is liable to malfunction.

  The polarizing plate on which the shield layer is formed generally has a structure in which a polarizer is sandwiched between a protective film (touch panel side film) and a counter film (display panel side film). At this time, if the moisture permeability of the counter film is high, the moisture in the shield layer moves to the counter film side via the protective film and the polarizer. That is, the moisture passes through the polarizer. For this reason, the polarizer is deteriorated due to the moisture, and a reddish display may occur during black display.

  Furthermore, if the thickness of the protective film increases too much, the polarizing plate tends to warp due to the moisture absorption of the protective film or the shrinkage or expansion due to temperature change.

  In view of the above circumstances, the object of the present invention is to shield the conductive layer from moisture even when the touch panel and the display device are bonded via a conductive layer (shield layer) and the conductive layer is formed by aqueous coating of nanowires. An object of the present invention is to provide a display device with a touch panel that can suppress the deterioration of the property and the deterioration of the polarizing plate and can suppress the warpage of the polarizing plate.

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

1. A display device with a touch panel in which a touch panel including a cover glass is bonded to the polarizing plate side of a display device having a polarizing plate on a display panel,
The polarizing plate has a polarizer, a protective film that is bonded to the surface of the polarizer on the touch panel side, and a counter film that is bonded to the back surface of the polarizer.
The protective film includes a cellulose ester film having a thickness of 15 to 30 μm, and a conductive layer formed by aqueous coating of nanowires on the touch panel side with respect to the cellulose ester film,
The facing film with a touch panel characterized by comprising the following optical film moisture permeability 200g / m 2 / ^24h display device.

  2. 2. The display device with a touch panel as described in 1 above, wherein retardation Ro in the in-plane direction of the cellulose ester film of the protective film is 0 nm to 10 nm.

  3. 2. The display device with a touch panel as described in 1 above, wherein an in-plane retardation Ro of the cellulose ester film of the protective film is 60 nm to 150 nm.

  4). 4. The display device with a touch panel according to any one of 1 to 3, wherein the nanowire is a silver nanowire.

  5. 5. The display device with a touch panel according to any one of 1 to 4, wherein the optical film of the counter film is a resin film made of cyclic polyolefin or acrylic.

  6). 6. The display device with a touch panel according to any one of 1 to 5, wherein retardation Ro in the in-plane direction of the optical film of the counter film is 0 nm to 10 nm.

  7). 6. The display device with a touch panel according to any one of 1 to 5, wherein retardation Ro in the in-plane direction of the optical film of the counter film is 120 nm to 150 nm.

  8). 8. The display device with a touch panel according to any one of 1 to 7, wherein the display panel is a liquid crystal display panel.

  9. 8. The display device with a touch panel according to any one of 1 to 7, wherein the display panel is an organic EL display panel.

  According to said structure, since the protective film of a polarizing plate contains the hygroscopicity and highly moisture-permeable cellulose-ester film, a conductive layer is formed by the aqueous | water-based application | coating of nanowire on the touch panel side with respect to this cellulose-ester film. Even if formed, moisture in the conductive layer can be absorbed by the cellulose ester film. Thereby, it can suppress that the shielding performance of a conductive layer falls with the said water | moisture content.

The counter films of the protective film includes a following optical film moisture permeability 200g / m 2 / ^24h, has low hygroscopicity, water content of the conductive layer, opposite the film side through the cellulose ester film and a polarizer Can be suppressed. As a result, deterioration of the polarizer due to the moisture can be suppressed.

  Moreover, since the thickness of the cellulose ester film of the protective film is as thin as 15 to 30 μm, the stress due to shrinkage and expansion when the moisture content of the cellulose ester film is changed is reduced, which causes warping of the polarizing plate. 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. It is sectional drawing which shows typically the structural example of the liquid crystal display panel as a display panel which the said display apparatus with a touch panel has. It is sectional drawing which shows typically the structural example of the organic electroluminescent display panel as said display panel.

  An embodiment of the present invention will be described below with reference to the drawings. In the present 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 constituted by a liquid crystal display panel (LCD) or an organic EL (Electro-Luminescence) display, details of which will be described later. The organic EL display panel is also called OLED (Organic light-Emitting Diode). 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.

  The polarizing plate 2 is laminated on a polarizer 3 that transmits predetermined linearly polarized light, a film 4 that is laminated on the surface of the polarizer 3 (touch panel 20 side), and a back surface of the polarizer 3 (display panel 1 side). It consists of a film 5. 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. A completely saponified polyvinyl alcohol aqueous solution is bonded as an adhesive to the front and back surfaces.

  The film 4 is configured as a hard coat film in which a hard coat layer 4b is laminated on a film substrate 4a, and has a function as a protective film for protecting the surface of the polarizing plate 2 (polarizer 3). . Although the film base material 4a can be comprised with various materials, in this embodiment, it is comprised with the cellulose ester film of thickness 15-30 micrometers among them.

  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.

  Further, in the film 4, the surface of the touch panel 20 side with respect to the film substrate 4a (cellulose ester film) (the surface on the touch panel 20 side of the hard coat layer 4b when the hard coat layer 4b is formed) is electrically conductive. Layer 40 is formed. The conductive layer 40 is provided for the purpose of blocking electrical noise from the display panel 1. For example, a coating liquid in which metal nanowires such as silver and copper are dispersed is applied to the substrate surface (aqueous coating). It is formed by drying.

  In the case where the display panel 1 is a liquid crystal display panel, another polarizing plate (not shown) is disposed on the opposite side of the display panel 1 from the polarizing plate 2. On the other hand, when the display panel 1 is an organic EL display panel, the polarizing plate 2 is preferably configured as a circularly polarizing plate (or an elliptically polarizing plate) for preventing external light reflection. 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 °.

Film 5 is an opposing film facing the film 4 through the polarizer 3, moisture permeability is constituted by an optical film is not more than 200g / m 2 / ^24h. 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. 40 μm. In addition, the moisture permeability in this invention represents what was measured on test conditions 40 degreeC and 90% RH.

  The touch panel 20 is a capacitive touch panel, and is formed by adhering a conductive film 23 via a pressure-sensitive adhesive layer 22 on a glass substrate 21 serving as a cover glass. The surface of the glass substrate 21 (the surface opposite to the conductive film 23 side) is a touch surface of the touch panel 20. The pressure-sensitive adhesive layer 22 is composed of an adhesive layer such as a transparent optical double-sided tape (OCA) or a UV curable resin (OCR).

  The conductive film 23 is formed by laminating a first electrode pattern made of a transparent conductive film (for example, ITO), an insulating layer, and a second electrode pattern made of a transparent conductive film (for example, ITO) on a film substrate. It is constructed and is also called a film sensor. Said film base material has a function as a scattering prevention film which prevents scattering of the glass substrate 21. The first electrode pattern and the second electrode pattern extend in the X direction and the Y direction orthogonal to each other in a plane parallel to the film substrate. An insulating layer may be formed on the second electrode pattern as necessary.

  In addition, the conductive film 23 may be configured by bonding the first electrode pattern to the surface of the film base material and bonding the second electrode pattern to the back surface. In addition, a hard coat layer may be formed on the film substrate for the purpose of surface protection.

  When the surface of the touch panel 20 is pressed with a finger, the capacitance between the first electrode pattern and the second electrode pattern of the conductive film 23 changes. By detecting the change in the capacitance via the first electrode pattern and the second electrode pattern, the pressed position (coordinates) can be specified.

  Similar to the pressure-sensitive adhesive layer 22, the pressure-sensitive adhesive layer 30 is configured by an adhesive layer such as OCA or OCR, and is formed on the entire surface of the conductive layer 40 to join the touch panel 20 and the display device 10. .

In said structure, the film 4 as a protective film of the polarizing plate 2 contains the film base material 4a which consists of a cellulose-ester film. Cellulose ester film, moisture permeability at a thickness of 80μm terms about 800~1000g ^/ m 2 ^/ 24h and a very high, excellent in hygroscopicity. For this reason, even if the conductive layer 40 is formed by the aqueous | water-based application | coating of metal nanowire, the water | moisture content of the conductive layer 40 can be absorbed with said cellulose-ester film.

  Therefore, in the configuration in which the glass substrate 21 is located on the outermost layer (the side opposite to the display panel 1) of the touch panel 20 as in the present embodiment, moisture in the conductive layer 40 cannot pass through the glass substrate 21. Although it does not escape to the outside of the touch panel 20, even in such a configuration, the moisture of the conductive layer 40 is absorbed by the cellulose ester film (film 4) inside the glass substrate 21, and the conductive layer 40 receives moisture. Can be prevented from accumulating. Thereby, it can suppress that the shielding performance of the conductive layer 40 falls with said water | moisture content, and the noise from the display panel 1 can be interrupted | blocked by the conductive layer 40 reliably. As a result, the malfunction of the touch panel 20 due to the noise can be suppressed. Such an effect can be obtained regardless of the metal material of the metal nanowire used for the aqueous coating. For example, even if the metal nanowire is a silver nanowire, the above effect can be obtained.

Moreover, the film 5 as an opposing film contains the optical film of moisture permeability 200g / m < ² > / 24h or less. Since the optical film has low moisture permeability and low hygroscopicity as described above, the moisture in the conductive layer 40 moves to the film 5 side through the film substrate 4a (cellulose ester film) and the polarizer 3. It becomes difficult and the hygroscopic property in the film base material 4a can further be improved. As a result, deterioration of the polarizer 3 due to moisture in the conductive layer 40 can be suppressed, and a reddish display can be suppressed even during black display. In particular, since a resin made of COP or acrylic has a low moisture permeability as described above, it is possible to reliably suppress deterioration of the polarizer 3 by forming the optical film using such a resin.

  Moreover, since the thickness of the cellulose ester film which comprises the film base material 4a of the film 4 is as thin as 15-30 micrometers, the stress which generate | occur | produces by shrinkage | contraction and expansion | swelling at the time of moisture absorption or drying becomes small. It is possible to suppress the occurrence of warping.

  By the way, in the cellulose ester film of the film 4 described above, the retardation Ro in the in-plane direction may be 0 nm to 10 nm. In this case, since there is little interference due to the phase difference in the in-plane direction, the visibility when viewing the display device 10 with the naked eye via the touch panel 20 can be improved.

  In addition, when setting the retardation Ro of the cellulose ester film of the film 4 to 0 nm to 10 nm, it is realized by setting the bonding angle of the cellulose ester film (film substrate 4a) to the polarizer 3 to 0 ° to 15 °. Is preferred. Here, the bonding angle is an angle formed between the absorption axis of the polarizer 3 and the slow axis of the cellulose ester film. The direction of the slow axis of the cellulose ester film at this time is determined by the Abbe refractometer (1T) as the average in-plane refractive index of the sample at a light wavelength of 590 nm under an environment of a temperature of 23 ° C. and a relative humidity of 55% RH. It can be determined by measurement. By setting such an angle, even when the retardation in the in-plane direction slightly varies, the optical influence can be reduced.

  In the cellulose ester film of the film 4 described above, the retardation Ro in the in-plane direction may be 60 nm to 150 nm. In this case, it is preferable to arrange the protective film so that the slow axis of the protective film 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. .

  In addition, when the display panel 1 is an LCD, the film 5 as the counter film may be simply provided 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. The retardation Ro in the in-plane direction is preferably 0 nm to 10 nm. The film 5 is preferably an optical film that imparts in-plane retardation of about ¼ of the transmission wavelength, preferably 120 nm to 150 nm of retardation Ro in the in-plane direction.

  When the display panel 1 is an OLED display, for example, for incident light having a wavelength of 550 nm, the optical film functions as a quarter-wave plate, and a combination of the optical film and the polarizer 3 forms a circularly polarizing plate. In addition, an external light reflection preventing function can be provided. Further, when the display panel 1 is, for example, a liquid crystal display panel, luminance reduction due to the presence of a liquid crystal disclination portion (a portion where the alignment of the liquid crystal is discontinuous) is caused by the optical film (¼ wavelength plate) Can be improved.

[Display panel]
FIG. 2 is a cross-sectional view schematically showing a configuration example of the liquid crystal display panel 50 as the display panel 1. The liquid crystal display panel 50 is configured by sandwiching a liquid crystal layer 53 between two substrates 51 and 52. The liquid crystal layer 53 is sealed between the two substrates 51 and 52 by a sealing material 54. On one substrate 51, a pixel electrode corresponding to each pixel, a TFT which is a switching element for controlling ON / OFF of display in each pixel, and various wirings (scanning lines and signal lines) connected to the TFT are provided. And an alignment film for aligning liquid crystal molecules. On the other substrate 52, a common electrode, a color filter for performing color display, and an alignment film are formed. With respect to such a liquid crystal display panel 50, the above polarizing plate 2 is disposed on one side, and on the other side, another polarizing plate (not shown) and a backlight ( (Not shown).

  In the above configuration, light (linearly polarized light) transmitted through the polarizing plate on the back side out of the light emitted from the backlight is incident on the liquid crystal layer 53 through the substrate 51 and propagates in the thickness direction of the liquid crystal layer 53. However, the polarization state changes according to the refractive index anisotropy (birefringence) of the liquid crystal. Of the light that has passed through the liquid crystal layer 53 and the substrate 52, only the light having the polarization component in a specific direction is emitted as display light by the polarizing plate 2 on the front side. The display is performed by changing the voltage applied to the liquid crystal layer 53 to change the orientation of the liquid crystal molecules.

  On the other hand, FIG. 3 is a cross-sectional view schematically showing a configuration example of the organic EL display panel 60 as the display panel 1. The organic EL display panel 60 includes a metal electrode 62, a light emitting layer 63, a transparent electrode (ITO, etc.) 64, and a sealing layer 65 in this order on a substrate 61 made of glass, polyimide, or the like. The metal electrode 62 may be composed of a reflective electrode and a transparent electrode.

  In the above configuration, when a voltage is applied to the metal electrode 62 and the transparent electrode 64, electrons are injected into the light emitting layer 63 from the electrode serving as the cathode among the metal electrode 62 and the transparent electrode 64, and serving as the anode. Holes are injected from the light source and recombined in the light emitting layer 63, whereby visible light emission corresponding to the light emission characteristics of the light emitting layer 63 occurs. The light generated in the light emitting layer 63 is taken out to the outside directly or after being reflected by the metal electrode 62 through the transparent electrode 64.

[About polarizing plate]
Hereinafter, the detail of each layer which comprises the above-mentioned polarizing plate 2 is demonstrated. In addition, about the film base material and hard coat layer which are shown below, it is applicable also to the film base material and hard coat layer of the conductive film 23 of the touch panel 20.

[Film substrate]
A thermoplastic resin or a thermosetting resin can be used as the film base 4a and the film 5 of the polarizing plate 2 (hereinafter, when it is not necessary to distinguish between them, they are collectively referred to as a film base). .

(Thermoplastic resin)
A thermoplastic resin refers to a resin that becomes soft when heated to the glass transition temperature or melting point and can be molded into the 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 the present embodiment, a particularly suitable resin will be described in detail.

<Cellulose ester resin>
The cellulose ester resin that can be used in this embodiment is selected from cellulose (di, tri) acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose phthalate. It is preferable that it is at least one kind.

  Among these, particularly preferable 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 an 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.

  Furthermore, 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, More preferably, it is 2.5-5.0, More preferably, 3.0-5.0 cellulose ester is used preferably.

  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. It is preferable that it is 6-7 and electrical conductivity is 1-100 microsiemens / 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. 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 cooling dissolution method as described in JP-A-9-95538 and a high-pressure method as described in JP-A-11-21379 can be used. The method of pressurizing at a boiling point or higher is preferred.

  Return 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.

  A pressure die that can adjust the slit shape of the die base portion and can easily make the film thickness uniform is preferable. 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 to 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.

  In addition, it is preferable that the residual solvent amount at the time of peeling of the web on the metal support at the time of peeling is peeled in the range of 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 at the time of peeling the metal support and the film is usually 196 to 245 N / m. If wrinkles easily occur during peeling, peeling is preferably performed with a tension of 190 N / m or less, and further, peeling is performed with a minimum tension that can be peeled to 166.6 N / m, and then with a minimum tension of 137.2 N / m. It is preferable to peel off at a minimum tension of -100 N / m.

  In the present 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 residual solvent. Throughout the drying is generally carried out at 40-250 ° C. It is particularly preferable to dry at 40 to 160 ° C.

  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 the zones do not interfere with each other.

  In addition, extending | stretching operation may be divided | segmented and implemented in multiple steps, and it is also preferable to implement biaxial stretching in a casting direction and a 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) Stretching in the casting direction-Stretching in the width direction-Stretching in the casting direction-Stretching in the casting direction b) Stretching in the width direction-Stretching in the width direction-Stretching in the casting direction-Stretching in the casting direction

  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 in 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 in the web is 10% by mass or less. More preferably, it is 5% by mass or less.

  30-160 degreeC is preferable, as for the drying temperature in the case of extending | stretching, 50-150 degreeC is more preferable, and 70-140 degreeC is the most preferable.

  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 method may be used. There are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, and the like.

  The film base material according to the present embodiment is preferably a long film, and specifically, has a thickness of about 100 m to 5000 m and is usually provided in a roll shape. Moreover, it is preferable that the width | variety of a film is 1.3-4m, and it is more preferable that it is 1.4-2m.

<Manufacturing method of base material by melt casting film forming method>
Next, a method for producing a film base material by a 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 decomposition of the raw material. In particular, since the 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 to keep the moisture content at 200 ppm or less, and further 100 ppm or less.

  The 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 that the shearing force is suppressed and the resin can be pelletized so as not to 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.

  A film is formed 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, using a single-screw or twin-screw type extruder, the melt temperature Tm when extruding the pellet is about 200 to 300 ° C., filtered through a leaf disk type filter or the like to remove foreign matters, 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 or reduced pressure or in an inert gas atmosphere.

  When foreign matter such as scratches or plasticizer aggregates adheres to the die, streak-like 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 contacts 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 having a 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.

  Although there is no restriction | limiting in particular in a cooling roll, What is necessary is just a roll provided with the structure where the heat medium which can control temperature inside, or a refrigerant | coolant body flows with 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.

  Examples of the surface material of the cooling roll include carbon steel, stainless steel, aluminum, and titanium. 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 chill 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 03-124425, JP 08-224772, JP 07-1000096, JP 10-272676, WO 97/028950, JP 11-235747, JP 2002-2002. It is possible to use a silicon rubber roll whose surface is coated with a thin film metal, as described in Japanese Patent Nos. 36332, 2005-172940, and 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. 2004-18279, paragraph numbers 0023 to 0039, Japanese Patent Application Laid-Open No. 10-306175, Japanese Patent Application Laid-Open No. 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 a phosphorus compound is 0.01-10 mass parts normally with respect to 100 mass parts of resin, Preferably it is 0.05-5 mass parts, More preferably, it is 0.1-3 mass parts.

(Other antioxidants)
Dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropioate) Nate) and the like, 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 and the like, heat-resistant processing stabilizers 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 ether (ie, 4,4'-dihydroxydiphenyldimethylmethane), epoxidized unsaturated fatty acid ester (especially an ester of an alkyl of about 2 to 2 carbon atoms of a fatty acid of 2 to 22 carbon atoms (e.g. 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, which generally contain 12 to 22 carbon atoms)).

<Light stabilizer>
Light stabilizers include hindered amine light stabilizer (HALS) compounds, which are known compounds, such as columns 5-11 of US Pat. No. 4,619,956 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 them 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. Moreover, you may use the ultraviolet absorber of Unexamined-Japanese-Patent No. 10-182621, Unexamined-Japanese-Patent No. 8-337574, and the polymeric ultraviolet absorber of Unexamined-Japanese-Patent No. 6-148430.

  In the present embodiment, the ultraviolet absorber is preferably added 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 film substrate 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, a 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 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, with the total composition being 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 unpreferable.

(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 above-mentioned cationically polymerizable compound is contained in the hard coat layer composition, the amount of the cationically polymerizable compound in the hard coat layer composition is usually 1 to 90 parts by mass when the entire composition is 100 parts by mass. 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 from 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.

  Moreover, it is preferable to make the hard coat layer contain reactive silica fine particles (Xa) surface-treated with an organic compound having a polymerizable unsaturated group from the viewpoint of better exhibiting the effects of the present embodiment. Hereinafter, the reactive silica fine particles (Xa) surface-treated with an organic compound having a polymerizable unsaturated group will be described.

  Moreover, it is preferable that a hard-coat layer contains the active energy ray-curable resin and microparticles | fine-particles which were mentioned above, and is active energy ray-curable resin: microparticles | fine-particles = 90: 10-20: 80 by content 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. As a compounding quantity of a photoinitiator, it is preferable by mass ratio that it is photoinitiator: active energy ray hardening-type resin = 20: 100-0.01: 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.

  Moreover, the hard coat layer may contain the same ultraviolet absorber as the above-mentioned 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. As content of a ultraviolet absorber, it is preferable that it is a mass ratio and is ultraviolet absorber: hard-coat layer composition = 0.01: 100-10: 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-layer 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 a drying process, the layers are stacked one after another by an extrusion coater or simultaneously by 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 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 the wet film thickness. The dry film thickness is preferably about 5 to 20 μm, and 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 the film having the 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 a 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 refractive index in the 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 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 by adding fine particles to the hard coat layer or a method of forming protrusions on the surface by pressing the mold. 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.

  As acrylic adhesives, 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 In combination, isocyanate crosslinker, epoxy crosslinker, aziridine crosslinker, metal chelate crosslinker It includes a crosslinking agent that is reacted.

  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. . The thickness of a preferable adhesive layer is 3-12 micrometers.

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. The storage elastic modulus of a preferable 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 a film on the pressure-sensitive adhesive layer prepared by applying a pressure-sensitive adhesive-containing composition to a 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 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, 0.03~3.0g / ^{m 2} is preferred. The release sheet is laminated with the surface having the release agent in contact with the pressure-sensitive adhesive layer.

[Conductive layer]
The conductive layer as the shield layer (corresponding to the conductive layer 40 in FIG. 1) preferably contains at least a conductive substance, and further contains a binder, a photosensitive compound, and, if necessary, other components.

[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 that either the fiber of a solid structure and a hollow structure, or an electroconductive polymer is contained.

  Here, the solid structure fiber may be referred to as a wire, and the hollow structure fiber may be referred to as a tube.

  In addition, a conductive fiber 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 “nanowire”.

  In addition, conductive fibers 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 “nanotubes”.

  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, and iridium. 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 short axis length of the metal nanowires was measured using a transmission electron microscope (TEM; manufactured by JEOL Ltd., JEM-2000FX), and 300 metal nanowires were observed. 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 (sometimes referred to as “average length”) of the metal nanowires 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 major 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.

  There is no restriction | limiting in particular as a manufacturing method of the said metal nanotube, According to the objective, it can select suitably. 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.

  There is no restriction | limiting in particular as a manufacturing method of a carbon nanotube, According to the objective, it can select suitably. 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 conductive fiber preferably has an aspect ratio of 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).

  There is no restriction | limiting in particular as a measuring method of an aspect ratio, According to the objective, it can select suitably, For example, the method etc. which measure with an electron microscope etc. are mentioned.

  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 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. 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 comprising (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>
On the glass substrate as a cover glass, the conductive film produced as follows was affixed through the adhesive layer, and the touchscreen module was produced. At this time, OCA was used as the pressure-sensitive adhesive layer.

(Preparation of conductive film)
On the same film as the cellulose ester film A-1 as a protective film described later, a hard coat layer composition filtered through a polypropylene filter having a pore diameter of 0.4 μm was applied using a micro gravure coater. 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.

Next, an ITO film having a thickness of 20 nm was formed on the produced cellulose ester film of the hard coat film by a sputtering method, and this was etched to form a first electrode pattern extending in the X direction. Then, an insulating layer made of SiO ₂ having a thickness of 200 nm was formed on the first electrode pattern by a sputtering method. Thereafter, an ITO film having a thickness of 20 nm was formed on the insulating layer by a sputtering method, and this was etched to form a second electrode pattern extending in the Y direction. Further, an insulating layer made of SiO ₂ having a thickness of 200 nm was formed on the second electrode pattern by a sputtering method.

  After the conductive film is pasted on the glass substrate, Ag paste is applied to the first electrode pattern and the second electrode pattern of the conductive film and sintered, and the first electrode pattern, the second electrode pattern, and the control circuit are read. The touch panel module was completed by connecting via wires.

<Preparation of polarizing plate>
A polarizing plate is produced by bonding a protective film on one surface of a polarizing film as a polarizer and bonding a counter film on the other surface.

(Preparation of protective film)
[Production 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-1 100 parts by mass Polyester compound 6 parts by mass Sugar ester compound 6 parts by mass Particulate additive solution 1 1 part by mass 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 until the residual solvent amount in the cast (cast) film reached 75% on the stainless steel belt support, 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 having a width of 10 mm and a height of 10 μm was applied to both ends of the film, wound into a roll, and a cellulose ester film A-1 having a dry film thickness of 15 μm was obtained. The winding length was 5200 m.

In the cellulose ester film A-1, the retardation in the in-plane direction (retardation Ro) was 0 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-6]
Cellulose ester films A-2 to A-6 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.

[Formation of conductive layer]
<Silver nanowires>
Silver nanowires (AgNW) 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 solution 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-dispersed coating solution was applied onto cellulose ester films A-1, A-3 to A-6 using a bar coater manufactured by Matsuo Sangyo Co., Ltd., dried at 120 ° C. for 2 minutes, and then silver nanowires A coating was provided.

<Copper nanowire>
Copper nanowires (CuNW) 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, the blue colloidal dispersion was stirred at room temperature in the atmosphere, and 100 ml (0.5 mmol) of a 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.

(Preparation of counter film)
<Production of acrylic film>
Acrylic film B-1 was produced by the following method.

(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.

  Thereafter, a 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 Japanese Patent Application Laid-Open No. 11-235747 was used (the one described as a double holding roll, except that the thickness of the thin metal outer cylinder was 2 mm). In addition, the temperature of the triple cast roll containing a chill roll was made into touch roll temperature +3 degreeC, touch roll temperature -2 degreeC, and touch roll temperature -7 degreeC in order from the upstream.

  Then, after trimming both ends (5 cm each of the full width) immediately before winding, thicknessing (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 20 μm.

  Moreover, the acrylic film B-5 was produced like the acrylic film B-1 except having changed the film thickness and the in-plane retardation Ro as shown in Table 1.

<Production of COP film>
COP films B-2 to B-4 were produced by the following method.

<< Preparation of COP film B-2 >>
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 (made by Fuji Silysia Co., grade: G-3 particle size: 50 μm) whose adsorbed water content was adjusted to 10% by mass was added and reacted for 1 hour. The reaction solution was put into 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 to 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 B-2 having a dry film thickness of 25 μm. The winding length was 5000 m. About retardation of COP film B-2, retardation Ro was 120 nm.

<< Production of COP Films B-3, B-4, A-7 >>
COP films B-3, B-4, and A-7 were produced in the same manner as the COP film B-2 except that the film thickness and retardation Ro were changed as described in Table 1.

<Cellulose ester film>
The same thing as the cellulose-ester film A-2 of the protective film mentioned above was used as the cellulose-ester film B-6 of a counter film.

(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 preliminarily swollen in water at a temperature of 30 ° C. for 30 seconds, 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 the condition that the tension applied to the film was 700 N / m, and 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.

(Lamination of film on polarizer)
According to the following processes 1-4, the protective film was bonded together on the surface of the polarizing film, and the opposing film was bonded together on the back surface of the polarizing film, and the polarizing plate was produced.

[Process 1]
The aforementioned polarizing film was immersed in a storage tank of a polyvinyl alcohol adhesive solution having a solid content of 2% by mass for 1 to 2 seconds.

[Process 2]
The alkali treatment was performed on the cellulose ester film A-1 under the following conditions.
(Alkali treatment)
Saponification step 2.5 mol / L-KOH 50 ° C. 120 seconds Water washing step Water 30 ° C. 60 seconds Neutralization step 10 parts by mass HCl 30 ° C. 45 seconds Water washing step Water 30 ° C. 60 seconds After saponification treatment, water washing, neutralization, water washing in this order Followed by drying at 100 ° C.

  Next, the polarizing film was immersed in the polyvinyl alcohol adhesive solution used in Step 1. Excess adhesive adhered to the immersed polarizing film was lightly removed, and this polarizing film was sandwiched between the cellulose ester film A-1 and the acrylic film B-1, and laminated. At this time, the bonding angle between each film and the polarizing film, that is, the angle formed between the slow axis of each film and the absorption axis of the polarizing film was set as the bonding angle shown in Table 1.

[Process 3]
The laminate was laminated with two rotating rollers at a pressure of ^{20 to} 30 N / cm ² and a speed of about 2 m / min. At this time, care was taken to prevent bubbles from entering.

[Process 4]
The sample prepared in Step 3 was dried in a dryer at a temperature of 100 ° C. for 5 minutes to prepare a roll-shaped polarizing plate.

  Cellulose ester films A-2 to A-6 were also subjected to alkali treatment under the same conditions as described above, and were then attached to the polarizing film at the attachment angles shown in Table 1. Further, the counter films (COP films B-2 to B-4, acrylic film B-5, and cellulose ester film B-6) were also attached to the polarizing film at the sticking angles shown in Table 1.

  The combinations of the protective film and the counter film in the polarizing plates according to Examples 1 to 5 and Comparative Examples 1 to 4 are as shown in Table 1.

<Assembly of display device with touch panel>
The conductive film of the touch panel and the polarizing plate of the liquid crystal display device were bonded together via an adhesive layer to configure a liquid crystal display device with a touch panel. More specifically, the surface of the protective film (conductive layer) of the polarizing plate of the liquid crystal display device is coated with SVR1240 manufactured by Sony Chemical & Information Device Co. as a pressure-sensitive adhesive. A conductive film was attached. 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.

<Evaluation of display device with touch panel>
(1) Evaluation of shielding property The manufactured liquid crystal display device with a touch panel was subjected to a temperature change from −20 ° C. to 80 ° C. for 200 cycles at an interval of 30 minutes in an environment with a relative humidity of 50% RH. Then, the touch test of the touch panel module was performed and it was confirmed whether malfunction occurred. The evaluation criteria at this time are as follows.
○: No malfunction occurred when pressed 100 times.
(Triangle | delta): A malfunction is 1 time or more and less than 5 times when it presses 100 times.
X: Malfunction occurred 5 times or more when pressed 100 times.

(2) About Polarizer Deterioration After the produced display device with a touch panel was allowed to stand for 500 hours in an environment of 60 ° C. and 90%, 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.

(3) Curling of polarizing plate The produced polarizing plate is chip-cut into A4 size (29.7 × 21.0 cm), and is subjected to general environment (23 ° C., 50% RH) and humid environment (30 ° C., 90 ° % RH) for 24 hours, and the film curl height was measured. And the average value of the height of four corners was calculated, and the degree of curling of the polarizing plate was evaluated based on the following criteria.
A: The average height is 0 mm or more and less than 15 mm.
Δ: The average height is 15 mm or more and less than 30 mm.
X: The average height is 50 mm or more.

[Evaluation results]
In Comparative Example 2, since the protective film of the polarizing plate does not include a conductive layer, electrical noise from the display panel cannot be cut off, resulting in many malfunctions of the touch panel. On the other hand, in Example 1 etc., since the protective film includes a conductive layer and electrical noise can be blocked by the conductive layer, the shielding property is good. In addition, since the protective film includes a cellulose ester film having high hygroscopicity and moisture permeability, even if the conductive layer is formed by aqueous application of silver nanowires, the moisture of the conductive layer can be absorbed by the cellulose ester film. . For this reason, it is thought that the shielding fall by the water | moisture content of a conductive layer can be suppressed.

  Moreover, in Comparative Example 1 in which the opposing film of the protective film is a cellulose ester film, polarizer deterioration occurs. This is because the cellulose ester film has high moisture permeability and good hygroscopicity, so the moisture in the conductive layer easily moves to the counter film side through the protective film and the polarizer, and the moisture passes through the polarizer. I think that the. In contrast, in Example 1 or the like, the polarizer is not deteriorated, but this is because the counter film is a film having a low moisture permeability other than the cellulose ester film, and the transmission of the moisture in the polarizer is suppressed. I think that the.

  Furthermore, in Comparative Example 3, curling occurs in the polarizing plate, which is considered to be because the thickness of the cellulose ester film of the protective film is as thick as 40 nm, and stress due to shrinkage and expansion due to moisture absorption and drying increases. . On the other hand, in Example 1 etc., the polarizing plate is not curled. This is probably because the thickness of the cellulose ester film of the protective film is 15 to 30 nm and the generated stress is small.

  In Comparative Example 4, the protective film includes a COP film having low hygroscopicity, and the COP film cannot absorb the moisture of the conductive layer, so that the shielding property of the conductive layer is reduced by moisture. It seems to be. Further, since COP films having low hygroscopicity exist on both sides of the polarizer, it is considered that moisture in the conductive layer is trapped between these films, and the polarizer is deteriorated by this moisture.

As mentioned above, in Examples 1-5, the protective film of a polarizing plate contains the cellulose-ester film whose thickness is 15-30 micrometers, and the conductive layer formed by the aqueous | water-based application | coating of nanowire, because it contains moisture permeability 200g / m 2 / ^24h or less of the optical film, it is possible to suppress the moisture shielding property decreases and the polarizer degradation by the conductive layer, it can be said that it is possible to suppress the warping polarizing plate .

  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.

  The present invention can be used in a display device with a touch panel in which a touch panel including a cover glass is bonded to a polarizing plate on a display panel.

DESCRIPTION OF SYMBOLS 1 Display panel 2 Polarizing plate 3 Polarizer 4 Film (protective film)
4a Film substrate (cellulose ester film)
5 Film (opposite film)
DESCRIPTION OF SYMBOLS 10 Display apparatus 20 Touch panel 21 Glass substrate 30 Adhesive layer 40 Conductive layer 50 Liquid crystal display panel 60 Organic EL display panel

Claims (9)

A display device with a touch panel in which a touch panel including a cover glass is bonded to the polarizing plate side of a display device having a polarizing plate on a display panel,
The polarizing plate has a polarizer, a protective film bonded to the surface of the polarizer on the touch panel side, and a counter film bonded to the back surface of the polarizer,
The protective film includes a cellulose ester film having a thickness of 15 to 30 μm, and a conductive layer formed by aqueous coating of nanowires on the touch panel side with respect to the cellulose ester film,
The facing film with a touch panel characterized by comprising the following optical film moisture permeability 200g / m 2 / ^24h display device.   The display device with a touch panel according to claim 1, wherein retardation Ro in the in-plane direction of the cellulose ester film of the protective film is 0 nm to 10 nm.   The display device with a touch panel according to claim 1, wherein retardation Ro in the in-plane direction of the cellulose ester film of the protective film is 60 nm to 150 nm.   The display device with a touch panel according to claim 1, wherein the nanowire is a silver nanowire.   The display device with a touch panel according to claim 1, wherein the optical film of the counter film is a resin film made of cyclic polyolefin or acrylic.   The display device with a touch panel according to claim 1, wherein retardation Ro in the in-plane direction of the optical film of the counter film is 0 nm to 10 nm.   The display device with a touch panel according to claim 1, wherein retardation Ro in the in-plane direction of the optical film of the counter film is 120 nm to 150 nm.   The display device with a touch panel according to claim 1, wherein the display panel is a liquid crystal display panel.   The display device with a touch panel according to claim 1, wherein the display panel is an organic EL display panel.

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