CN106199810A - The manufacture method of polarization plates - Google Patents

Abstract

The present invention relates to one in the two-sided stacking respectively of polaroid (35) the manufacture method of the polarization plates being bonded with protective film (31,32); polaroid (35) and protective film (31,32) are overlapped via adhesive and obtain duplexer (37); then; above-mentioned duplexer (37) is made to adhere to the convex surface being formed as arc-shaped along the direction of transfer of this duplexer (37); it is preferably the outer surface of roller (38); irradiate the active energy ray from active-energy beam irradiating apparatus (39,40) simultaneously, make adhesive polymerizing curable.

Description

Manufacturing method of polarizing plate

This application is a divisional application of the application No. 200810191091.6 and the title of the invention "Method for Manufacturing Polarizing Plate" submitted by the applicant on November 24, 2008.

technical field

The present invention relates to a production method of a polarizing plate which is practical as one of optical components constituting a liquid crystal display device.

Background technique

A polarizing plate is practical as one of optical components constituting a liquid crystal display device. FIG. 4 shows a structure in which a linear polarizing film, which is a type of polarizing plate, is laminated on a liquid crystal cell. On the light source side surface of the liquid crystal cell 10 constituting the liquid crystal display panel, a linear polarizing film 12 is laminated with an adhesive layer 11 to form a liquid crystal display panel.

A polarizing plate is generally used in a state where a protective film is laminated on both sides of the polarizing plate, incorporated into a liquid crystal display device. That is, as shown in FIG. 5 , in a common polarizing plate 20, protective films 22, 23 are laminated and bonded via adhesive layers 24, 25 on both sides of a polarizing plate 21 (Japanese Patent Laid-Open No. JP2004-245925, Japanese Laid-Open JP2005- Bulletin No. 173216).

However, in the polarizing plate produced as described above, the side attached to the liquid crystal cell is curled into a depression (hereinafter referred to as "reverse curl"), and the entire polarizing plate is wavily formed (hereinafter referred to as "reverse curl"). wavy curl"). Such reverse curls and wavy curls tend to leave air bubbles on the bonding surface when the polarizing plate is bonded to the liquid crystal cell, which causes waste of the liquid crystal panel. Therefore, it is desired that the polarizing plate does not generate reverse curls and wavy curls, and if curls do not occur, or even if curls occur, the polarizing plate is curled to form protrusions on the side attached to the liquid crystal cell (hereinafter referred to as "normal curl").

Contents of the invention

An object of the present invention is to provide a production method and production apparatus of a polarizing plate that suppress the generation of reverse curl and wavy curl.

The inventors of the present invention have conducted many intensive studies in order to achieve the above object, and as a result, found that the occurrence of reverse curl and wave curl can be suppressed by polymerizing and curing the adhesive in a state where the following laminate is bent in a normal curl, From the completion of the present invention, the laminate is formed by laminating a protective film on one or both sides of a polarizing plate via an adhesive.

That is, a method for manufacturing a polarizing plate of the present invention, the polarizing plate is a polarizing plate in which a protective film is laminated on one side or both sides of the polarizing plate and bonded, wherein the polarizing plate and the protective film are passed through The adhesives are piled up to obtain a laminate, and then the laminate is adhered to a convex curved surface formed in an arc shape along the longitudinal direction (transfer direction) of the laminate, and the adhesive is polymerized and cured. As the convex curved surface, for example, the outer peripheral surface of a roller can be used.

As the above-mentioned polarizer, a polyvinyl alcohol film in which iodine or a dichroic dye is uniaxially stretched is adsorbed and oriented, and as one of the above-mentioned protective films, an amorphous polyolefin-based resin film is used as the above-mentioned protective film. Another example of the film is triacetyl cellulose film, but it is not limited thereto.

It is preferable to irradiate the laminated body adhered to the above-mentioned convex curved surface to polymerize and cure with active energy rays, or to heat to polymerize and cure.

In addition, the polarizing plate manufacturing apparatus of the present invention has a mechanism for applying an adhesive to one side of the protective film or both sides of the polarizer; a mechanism for superimposing the protective film on both sides of the polarizer through the adhesive layer; and a mechanism for polymerizing and curing the adhesive. wherein, the mechanism for polymerizing and curing the adhesive includes: a roller that adheres the polarizing plate after the protective film is attached to the outer peripheral surface and conveys it simultaneously, and an active energy that irradiates active energy rays to the outer peripheral surface of the roller. ray irradiation device.

According to the present invention, a laminate formed by laminating a polarizing plate and a protective film via an adhesive is formed into an arc-shaped convex surface along the longitudinal direction (conveyance direction) of the laminate, and simultaneously irradiated with active energy rays. The adhesive is polymerized and cured, so that when the polarizing plate is bonded to the liquid crystal cell, the occurrence of reverse curl and wavy curl can be suppressed. The generation of reverse curl and wavy curl is caused by remaining air bubbles on the bonding surface and causing the liquid crystal panel to occur. cause of deterioration.

Description of drawings

FIG. 1 is a schematic side view showing an embodiment of the apparatus for producing a polarizing plate of the present invention.

2(A) and (B) are explanatory diagrams showing a method of evaluating curl generated on a polarizing plate.

3 is an explanatory diagram showing a method of polymerizing and curing an adhesive by irradiation of active energy rays in Comparative Examples 1 and 2. FIG.

FIG. 4 is an explanatory diagram illustrating a structure in which a linear polarizing film, which is a type of polarizing plate, is laminated on a liquid crystal cell.

FIG. 5 is an explanatory diagram illustrating the structure of a polarizing plate.

Symbol Description

30: Manufacturing device of polarizing plate

31, 32: Protective film

33, 34: Adhesive coating device

35: Polarizer

36: pinch roller

37: laminated body

38: roll

39, 40, 41: Active energy ray irradiation device

42: Nipping roller for transmission

50: polarizing plate

51: wavelength

52: Amplitude

60: laminate

61: UV irradiation device

detailed description

Hereinafter, an embodiment of the present invention will be described. The polarizing plate in this embodiment is formed of a polarizing plate and a protective film laminated on both surfaces thereof via an adhesive. As the above-mentioned polarizer, polarizers conventionally used in the production of polarizing plates (for example, the polarizers described in the above-mentioned Japanese Patent Laid-Open No. 2004-245925 ) can be used, and generally uniaxially stretched polyvinyl alcohol using iodine Or dichroic dye dyeing, followed by boric acid treatment to form a thin film. The thickness of the polarizing plate is preferably in the range of 5 to 50 μm.

The protective films laminated on both sides of the polarizing plate may be of the same type or of different types. When using different types of protective films, use non-crystalline polyolefin resin films, polyester resin films, acrylic resin films, polycarbonate resin films, polysulfone resin films, and alicyclic polyimide resin films for one of the protective films Such as resin films with low moisture permeability. Amorphous polyolefin resin films include, for example, "TOPAS" manufactured by Ticona, Germany, "ARTON" manufactured by JSR (Co., Ltd.), "ZEONOR" and "ZEONOR" manufactured by ZEON (K.K.) in Japan. ZEONEX), "APPEL" manufactured by Mitsui Chemicals Co., Ltd., and the like. As the other protective film, acetyl cellulose ester-based films such as triacetyl cellulose films and diacetyl cellulose films are used other than the above-mentioned films. Examples of the triacetyl cellulose film include "FUJITAC TD80", "FUJITAC TD80UF" and "FUJITAC TD80UZ" manufactured by Fujifilm Corporation, and "KC8UX2M" and "KC8UY" manufactured by UNIKA Corporation.

Before the protective film is bonded to the polarizing plate, an alkali treatment, a corona discharge treatment, a primer treatment, an anchor coating treatment, and other adhesion-facilitating treatments may be applied to the bonding surface. In addition, the surface of the protective film opposite to the surface bonded to the polarizing plate may have various treatment layers such as a hard coat layer, an antireflection layer, and an antiglare layer. The thickness of the protective film is usually in the range of about 5 to 200 μm, preferably 10 to 120 μm, and more preferably 10 to 85 μm.

For adhesives, from the viewpoint of weather resistance, refractive index, cationic polymerizability, etc., for example, as described in JP2004-245925 A, a ring that does not contain an aromatic ring in the molecule can be used in the adhesive. Oxygen resin, but not limited thereto, various adhesives conventionally used in the production of polarizing plates can be used. As said epoxy resin, hydrogenated epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, etc. are used, for example. A polymerization initiator such as a photocationic polymerization initiator for polymerization by irradiation of active energy rays, a thermal cationic polymerization initiator for polymerization by heating, and other additives (activators, etc.) can be added to the epoxy resin component to prepare Adhesive composition for coating.

Hereinafter, the polarizing plate manufacturing apparatus and manufacturing method of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of the apparatus for producing a polarizing plate of the present invention.

In the polarizing plate manufacturing device 30 shown in Fig. 1, be provided with in sequence along the conveying direction: be used for the adhesive coating device 33,34 of adhesive agent coating adhesive on one side of protective film 31,32; Be used for overlapping protective film 31, 32. The nip roller 36 of the polarizer 35; the roller 38 for adhering the laminated body 37 bonded with the above-mentioned protective films 31, 32 and the polarizer 35; provided at a position opposite to the outer peripheral surface of the roller 38 The first active energy ray irradiation devices 39 and 40 ; the second active energy ray irradiation device 41 provided on the downstream side in the conveying direction; and the nip roller 42 for conveyance.

That is, the protective films 31 and 32 that are continuously drawn out from the roll-shaped state are coated with an adhesive on one side by the adhesive coating devices 33 and 34 . Similar to the protective films 31 and 32 described above, the protective films 31 and 32 are superimposed on both sides of the polarizing plate 35 drawn out continuously through the adhesive agent and the nip rolls 36 to form a laminate 37 . In the process of transporting the laminated body 37 while adhering to the outer peripheral surface of the roller 38 , the outer peripheral surface of the roller 38 is irradiated with active energy rays from the first active energy ray irradiation devices 39 and 40 to polymerize and cure the adhesive. Moreover, the 2nd active energy ray irradiation device 41 arrange|positioned on the downstream side of a conveyance direction is a device for fully polymerizing and hardening an adhesive agent, and can be omitted as needed.

The method of applying the adhesive to the protective films 31 and 32 is not particularly limited, for example, a doctor blade, a wire bar, a die coater, a comma coater, or a gravure plate can be used. Various coating methods such as printing coating. Among them, in film coating, the adhesive coating devices 33 and 34 are preferably gravure rolls in consideration of the degree of freedom with respect to the pass line, the correspondence with the width, and the like.

When gravure rolls are used as the adhesive coating devices 33 and 34 for adhesive coating, the thickness of the adhesive layer is adjusted according to the ratio of the gravure roll speed to the line speed, that is, the draw ratio. The line speed of protective film 31,32 is set as 15～50m/min, gravure roller is rotated to the opposite direction of the conveying direction of this protective film 31,32, and the speed of gravure roller is set as 5～500m/min. (stretch ratio 1-10), thereby adjusting the coating thickness of the adhesive layer to about 1-10 μm.

The outer peripheral surface of the roller 38 is configured as a mirror-finished convex curved surface, and the laminated body 37 is adhered to the surface while being conveyed, and the adhesive is polymerized and cured by the active energy ray irradiation devices 39 and 40 during this process. When polymerizing and curing the adhesive, as long as the laminate 37 is sufficiently adhered, the diameter of the roller 38 is not particularly limited, but the laminate 37 whose adhesive layer is in an uncured state is preferably passed through the roller 38 at a rate of 30 mJ/cm. The accumulated light amount of ultraviolet rays of ² irradiates active energy rays. The roller 38 may follow the linear motion of the laminated body 37 or be driven to rotate, or may be fixed so that the laminated body 37 slides on the surface thereof. In addition, the roll 38 may function as a cooling roll in order to prevent heat from being added to the laminate 37 during polymerization and solidification by irradiation of active energy rays. The surface temperature of the cooling roll at this time is preferably 20 to 25°C.

When polymerization and curing are carried out by irradiation of active energy rays, the light source used is not particularly limited, and one with a light emission distribution below 400nm can be used, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, an ultraviolet lamp, Microwave excited mercury lamps, metal halide lamps, etc. The intensity of light irradiation on the epoxy resin composition is not particularly limited depending on the target composition, but the intensity of irradiation in the wavelength region effective for activation of the initiator is preferably 0.1 to 100 mJ/cm ² . If the light irradiation intensity to the resin composition is less than 0.1mJ/cm ² , the reaction time will be too long, and if it exceeds 100mJ/cm ² , the epoxy resin composition may be formed due to the heat radiated from the lamp and the heat generated during the polymerization of the composition. Yellowing of objects and deterioration of polarizers.

The time for irradiating the composition with active energy rays is controlled for each polymerized composition and is not particularly limited, but is preferably set so that the cumulative light amount expressed as the product of irradiation intensity and irradiation time is 10 to 5000 mJ/cm ² . For example, if the accumulated light amount to the above-mentioned epoxy resin composition is less than 10 mJ/cm ² , the generation of activated species from the initiator is insufficient, and the curing of the obtained protective film may be insufficient. On the other hand, if the accumulated light amount exceeds If it is 5000mJ/cm ² , the irradiation time will be very long, which is disadvantageous for improving productivity.

When ultraviolet light is used as the active energy ray, the linear velocity of the laminate 37 is not particularly limited, but it is preferable to use a tension of 100 to 800 N, an irradiation intensity of at least 30 mJ/cm ² or more, and a speed of 0.3 seconds or more in the longitudinal direction (transportation direction). The laminated body 37 is irradiated with active energy rays under the condition of irradiation time. In addition, when the cumulative amount of active energy ray irradiation by the active energy ray devices 39 and 40 is not sufficient, an auxiliary second active energy ray device 41 may be provided to additionally irradiate active energy rays to complete the polymerization of the adhesive of the laminated body 37 .

The thus obtained polarizing plate, compared with the conventional case where the polarizing plate is horizontally conveyed and passed under the active energy ray device at a predetermined tension (see FIG. When sticking to a liquid crystal cell, air bubbles do not remain on the bonding surface, and occurrence of defects in a liquid crystal panel can be reduced.

Hereinafter, the present invention will be specifically described by giving examples, but the present invention is not limited to the following examples.

Example 1

An amorphous polyolefin resin film [ZEONOR] (manufactured by Zeon Co., Ltd., Japan) with a thickness of 75 μm and a triacetyl cellulose film [KC8U2MW] (manufactured by Konika Minolta Co., Ltd., Japan) with a thickness of 80 μm were prepared. On one side of each of the amorphous polyolefin resin film and the triacetyl cellulose film, an epoxy resin composition [KRX492] as an adhesive was applied using a microchamber coating machine (manufactured by Fuji Machinery Co., Ltd.) as an adhesive coating device. -30] (manufactured by ADEKA Corporation). By setting the linear speed of the laminated body to 11 m/min, making the gravure roll rotate in the opposite direction to the conveying direction of the laminated material, and setting the speed of the gravure roll to 22 m/min, the thickness of the adhesive layer is about is 2 μm.

Next, the non-crystalline polyolefin resin film and the triacetyl cellulose film were bonded via the epoxy resin composition on both sides of the 25 μm-thick polyvinyl alcohol-based film in which iodine was adsorbed and oriented. coincide.

The polarizing plate was passed along the longitudinal direction at a linear speed of 11 m/min under a tension of 600 N while adhering the surface on which the triacetyl cellulose film of the polarizing plate was laminated to the outer peripheral surface of a cooling roll at 23°C. Among the ultraviolet rays irradiated by the EHAN1700NAL high-pressure mercury lamp 2 which is an ultraviolet lamp included in an ultraviolet irradiation device (manufactured by GS-YUASA Co., Ltd.). The cumulative ultraviolet light intensity at this time was 110 (mJ/cm ² ). The cumulative light intensity of ultraviolet rays is measured based on irradiation in the UVB region with a wavelength region of 280 to 320 nm. Thereafter, the laminated body having a width direction of 1330 mm was cut at 600 mm in the longitudinal direction, and the degree of wave curl was evaluated by the following method.

That is, as shown in FIG. 2 , the wave number, wavelength, and amplitude of the downward-facing polarizing plate 50 to which the triacetyl cellulose film was bonded were measured. The wave number is the number of peaks aligned in the width direction of the polarizing plate 50. As shown in FIG. In addition, as shown in FIG. 2(A), the amplitude 52 measures the length between the apexes of the crests and troughs at positions a to e that divide the polarizing plate 50 into five equal parts in the width direction, and is half the value of the length. The above measurement results are shown in FIG. 1 .

Example 2

A polarizing plate was obtained in the same manner as in Example 1 except that the cumulative light intensity of ultraviolet rays was 143 (mJ/cm ² ). The results are shown in Table 1.

Comparative example 1

A laminate 60 formed by laminating an amorphous polyolefin resin film and a triacetyl cellulose film on both sides of a polyvinyl alcohol film via an epoxy resin composition [KRX492-32] (manufactured by ADEKA Corporation) as an adhesive, such as As shown in Fig. 3, under the tension of 600N, under the condition of not sticking to the roller, the ultraviolet rays possessed by the ultraviolet irradiation device 61 (FUSION: made by Fu-jung Co., Ltd.) The lamp, that is, LH10-60UV electrodeless lamp 1, is irradiated with ultraviolet rays to make it polymerized and cured. At this time, the cumulative light intensity of ultraviolet rays was 119 (mJ/cm ² ). In addition, a polarizing plate was obtained in the same manner as in Example 1. The results are shown in Figure 1.

Comparative example 2

A polarizing plate was obtained in the same manner as in Comparative Example 1 except that the cumulative light intensity of ultraviolet rays was 27 (mJ/cm ² ). The results are shown in Table 1.

Table 1

As shown in Table 1, both of the polarizing plates of Comparative Example 1 and Comparative Example 2 produced wave curls, and compared with Comparative Example 2, the polarizing plate of Comparative Example 1 having a larger accumulated light amount of ultraviolet rays produced stronger wave curls. On the other hand, the wave number of the polarizing plates obtained in Example 1 and Example 2 was 0, and the generation of reverse curl and wavy curl was suppressed. Furthermore, in Examples 1 and 2, the obtained film was cut into a rectangle of 20 cm x 30 cm, set on a flat plate, and the state of bending (curl) at the four corners was checked, but no curl was observed at all.

Claims (13)

1. A method of manufacturing a polarizing plate in which the occurrence of wave curl is suppressed, which is a method of manufacturing a polarizing plate in which a protective film is laminated on one or both sides of a polarizing plate and bonded, wherein, The polarizer and the protective film are superimposed through an adhesive to obtain a laminate, and then, the laminate is adhered to a convex surface formed in an arc shape along the longitudinal direction of the laminate, and the laminate is irradiated with The active energy rays polymerize and cure the adhesive. 2. The manufacture method of polarizing plate as claimed in claim 1, wherein, The convex curved surface is the outer peripheral surface of the roller. 3. The manufacture method of polarizing plate as claimed in claim 2, wherein, The surface temperature of the roller is 20-25°C. 4. The manufacture method of polarizing plate as claimed in claim 2, wherein, The laminate with the adhesive layer in an uncured state was irradiated with active energy rays at a cumulative ultraviolet light intensity of 30 mJ/cm ² while passing through the roller. 5. the manufacture method of polarizing plate as claimed in claim 1 or 2, wherein, The polarizer is a polyvinyl alcohol film that has been uniaxially stretched and iodine or a dichroic dye is adsorbed and oriented. One of the protective films is an amorphous polyolefin resin film, and the other is a triacetyl cellulose film. . 6. The manufacture method of polarizing plate as claimed in claim 1, wherein, The thickness of the adhesive layer is 1-10 μm. 7 . The method for manufacturing a polarizing plate according to claim 1 , wherein the irradiation intensity of the active energy rays is 0.1-100 mJ/cm ² . 8. The manufacture method of polarizing plate as claimed in claim 1, wherein, The active energy ray is irradiated on the downstream side of the convex curved surface in the conveying direction to completely polymerize and cure the adhesive. 9. An apparatus for producing a polarizing plate in which the generation of wave curl is suppressed, comprising: Mechanism for coating adhesive on one side of a protective film or both sides of a polarizer; A mechanism for superimposing the protective film on one or both sides of the polarizer via an adhesive layer; and A mechanism for polymerizing and curing an adhesive wherein, The mechanism for polymerizing and curing the adhesive includes: a roller for conveying a polarizer laminated with a protective film to its outer peripheral surface while adhering it; and an active energy ray irradiation device for irradiating active energy rays to the outer peripheral surface of the roller. . 10. The polarizing plate manufacturing apparatus according to claim 9, wherein the active energy ray irradiation device is an ultraviolet irradiation device. 11 . The apparatus for manufacturing a polarizing plate according to claim 9 , wherein the irradiation intensity of the active energy rays is 0.1-100 mJ/cm ² . 12. The manufacturing apparatus of polarizing plate as claimed in claim 9, wherein, A second active energy ray irradiation device for completely curing the adhesive is provided on the downstream side of the active energy ray irradiation device in the conveyance direction. 13. The manufacturing apparatus of polarizing plate as claimed in claim 9, wherein, The surface temperature of the roller is 20-25°C.