JP2015206967A - Method for manufacturing composite polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polarizing plate, in which even when an adhesive having high solubility with a transparent resin film is used in a process of bonding the transparent resin film and a polarizing film, cutting in the transparent resin film can be prevented.SOLUTION: A polarizing film, a first transparent resin film and a second transparent resin film are each conveyed in a long state and laminated. The first transparent resin film and a first adhesive composition have a such relationship that when the first adhesive composition is applied on the first transparent resin film as a single body while a tension of 18 N/50 mm width is applied in a conveyance direction of the resin film, a time period until the film is cut is 120 seconds or less. The method for manufacturing a polarizing plate includes: a lamination step of laminating the first transparent resin film and the second transparent resin film via a second adhesive layer or a pressure-sensitive adhesive layer; a first bonding step of bonding the polarizing film to the first transparent resin film via the first adhesive composition; and a first curing step of curing the first adhesive composition to form a first adhesive layer; and these steps are carried out in the described order.

Description

  The present invention relates to a method for producing a composite polarizing plate useful as one of optical components constituting a liquid crystal display device.

  The polarizing plate is useful as one of the optical components constituting the liquid crystal display device. The polarizing plate is usually used by being incorporated in a liquid crystal display device in a state where a transparent resin film is laminated as a protective film on both surfaces of the polarizing film. As a method for producing such a polarizing plate, for example, a method described in Japanese Patent No. 4861968 (Patent Document 1) may be mentioned. In this method, a polarizing film and a protective film, which are continuously drawn out from a state of being wound in a roll shape, are overlapped with an adhesive to form a laminate, and the active energy is applied to the laminate by a predetermined method. A polarizing plate is produced by irradiating a wire and curing the adhesive.

  Conventional polarizing plates used protective films for the purpose of preventing shrinkage and performance degradation of polarizing films, but recently with the multi-functionality of the films, a plurality of resin films having functionality at the same time as protection have been laminated. A polarizing plate has been proposed. For example, Japanese Patent Laying-Open No. 2010-217870 (Patent Document 2) discloses a configuration that is particularly a polarizing plate used in an IPS mode liquid crystal cell and that is less likely to cause color unevenness and has excellent viewing angle characteristics. Specifically, a transparent protective film is laminated on one surface of the polarizing film, and a first retardation film made of an olefin resin is laminated on the other surface of the polarizing film. The structure of the composite polarizing plate in which a specific second retardation film is laminated on the outer side of the adhesive layer is described. In addition, in Japanese Patent No. 4880719 (Patent Document 3), as a configuration of a high-brightness polarizing plate with a small amount of color shift, a polarizing plate in which a protective film is provided on one side or both sides of a polarizing film and a brightness improving film In addition, a configuration is described in which a protective film is sandwiched therebetween and an adhesive layer is interposed therebetween.

  In these polarizing plates, a retardation film or a protective film is laminated on a polarizing film, and another retardation film or a brightness enhancement film is bonded to the surface opposite to the surface on which the polarizing film is laminated. It is a thing of the structure by which the several transparent resin film was laminated | stacked on the single side | surface of the polarizing film.

Japanese Patent No. 4861968 (JP 2009-134190 A) JP 2010-217870 A Japanese Patent No. 4880719 (JP 2009-157392 A)

  By the way, the present inventors previously found that when different transparent resin films are laminated, a laminate having high adhesion can be obtained by using an adhesive containing a component that dissolves each film. A patent application has been filed as 2013-113739. However, this method has a problem that if an adhesive is applied to the film in a state in which the film is under tension, the film is cut during the conveyance of the film.

  The object of the present invention is to provide a method for producing a polarizing plate in which the transparent resin film is not cut even when an adhesive having high solubility of the transparent resin film is used in the step of bonding the transparent resin film and the polarizing film. There is.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have previously laminated a plurality of transparent resin films to be laminated, and then bonded to a polarizing film, whereby the solubility of the transparent resin film is high. It has been found that even when an adhesive is used, cutting of the transparent resin film in the production process of the polarizing plate is suppressed, and the present invention has been completed.

  That is, in the present invention, a first transparent resin film is laminated on a polarizing film made of a polyvinyl alcohol-based resin via a first adhesive layer formed from a first adhesive composition, and the first A method for producing a composite polarizing plate in which a second transparent resin film is laminated on a transparent resin film via a second adhesive layer or a pressure-sensitive adhesive layer, wherein the polarizing film, the first transparent resin film, And the second transparent resin film are laminated while being transported in a long shape, and the first transparent resin film and the first adhesive composition are 18 N / in the transport direction of the first transparent resin film alone. When the first transparent resin film is applied onto the first transparent resin film under a tension of 50 mm, the first transparent resin film and the first adhesive composition come into contact with each other. 1 transparent resin film It has a relationship that the time until cutting is 120 seconds or less, and the manufacturing method described above involves the first transparent resin film and the second transparent resin film via the second adhesive layer or the pressure-sensitive adhesive layer. Laminating step, laminating the polarizing film to the first transparent resin film via the first adhesive composition, and curing the first adhesive composition to cure the first adhesive composition The present invention provides a method for producing a composite polarizing plate comprising a first curing step for forming an adhesive layer and performing each step in this order.

  The first adhesive composition described above is preferably cured by irradiation with active energy rays.

  In the above composite polarizing plate, the first transparent resin film and the second transparent resin film are laminated in this order on one surface of the polarizing film, and the third surface is formed from the third adhesive composition on the other surface of the polarizing film. A third transparent resin film is laminated via a third adhesive layer, and the manufacturing method further includes a third transparent resin film via a third adhesive composition on the polarizing film. 2nd bonding process which bonds together, and the 2nd hardening process of hardening the 3rd adhesive composition and forming the 3rd adhesive layer.

  In said manufacturing method, it is preferable to perform a 1st bonding process and a 2nd bonding process simultaneously, and to perform a 1st hardening process and a 2nd hardening process simultaneously. Moreover, it is preferable that a 3rd adhesive composition is what hardens | cures by irradiation of an active energy ray.

  The first transparent resin film described above is preferably a retardation film made of an olefin resin. Moreover, it is preferable that the 2nd transparent resin film is a phase difference film in which the surface laminated | stacked on the 1st transparent resin film is a methacrylic resin layer.

  According to the present invention, when a laminate in which a plurality of transparent resin films are laminated is used in a method for producing a polarizing plate in which a polarizing film is laminated on at least one side, an adhesive having high solubility of the transparent resin film is used. However, the cutting | disconnection of the transparent resin film which generate | occur | produces in the manufacturing process of a polarizing plate is suppressed.

It is a cross-sectional schematic diagram which shows the example of arrangement | positioning of an apparatus suitable for performing the lamination process (1) in this invention. It is a cross-sectional schematic diagram which shows the example of arrangement | positioning of an apparatus suitable for performing the 1st bonding process (2)-2nd hardening process (5) in this invention.

[Production method of composite polarizing plate]
In the method for producing a composite polarizing plate of the present invention, a first transparent resin film and a second transparent resin film are laminated via a second adhesive layer or an adhesive layer, and the first transparent resin film / On the surface on the first transparent resin film side of the laminate obtained in the lamination step (1) and the lamination step (1) for producing a laminate of the second transparent resin film, the first adhesive composition is interposed. The polarizing film is bonded, the first bonding step (2) for producing a laminate of the polarizing film / first transparent resin film / second transparent resin film, and the first adhesive composition are cured. The first curing step (3) for forming the first adhesive layer is provided and performed in this order. Thus, the composite polarizing plate manufactured is a polarizing film, a 1st adhesive bond layer, a 1st transparent resin film, a 2nd adhesive bond layer or an adhesive layer, and a 2nd transparent resin film in this order. It will be laminated.

  In addition, the above-described composite polarizing plate has a third polarizing plate on the other surface (the surface opposite to the surface on which the first transparent resin film and the second transparent resin film are laminated), as required. A third transparent resin film may be laminated via a third adhesive layer formed from the adhesive composition. In this case, the method for producing the composite polarizing plate further comprises a third transparent resin film bonded to the polarizing film via the third adhesive composition, and the third transparent resin film / polarizing film / first transparent. 2nd bonding process (4) which produces the laminated body of a resin film / 2nd transparent resin film, and 2nd hardening which hardens a 3rd adhesive composition and forms a 3rd adhesive bond layer It is preferable to provide a process (5). At this time, a 1st bonding process (2) and a 2nd bonding process (4) may be performed simultaneously, and a 1st hardening process (3) and a 2nd curing process (5) may be performed simultaneously. it can.

  In addition, when performing bonding of said 1st transparent resin film and 2nd transparent resin film, bonding of a polarizing film and a laminated body, and bonding of a polarizing film and a 3rd transparent resin film, it adhere | attaches. In order to improve the property, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, solvent treatment, and saponification treatment may be appropriately performed on each bonding surface. Examples of the saponification treatment include a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide. Hereafter, the manufacturing method of the composite polarizing plate of this invention is demonstrated, referring a figure suitably.

  FIG. 1 is a schematic cross-sectional view showing an arrangement example of an apparatus suitable for performing the lamination step (1). In FIG. 1, a coating device 12 for applying an adhesive (adhesive composition) to one side of the first transparent resin film 10, and the first transparent resin film 10 and the second transparent resin film 14 are bonded together. The example of the apparatus which provided the nip roll 13 and the active energy ray irradiation apparatus 18 in order along the conveyance direction was shown.

  With reference to FIG. 1, first, the first transparent resin film 10 is continuously fed out from a feeding roll, and an adhesive composition is applied to the bonding surface by a coating device 12. Next, the first transparent resin film 10 is pasted by the nip roll 13 and the second transparent resin film 14 that is continuously fed from the feeding roll in the same manner as the first transparent resin film 10 through this adhesive composition. Thereafter, the adhesive composition is cured by irradiating active energy rays with the active energy ray irradiating device 18 to obtain a first transparent resin film / second transparent resin film laminate 20. The laminate 20 may be wound up or supplied to the next step without being wound up. In FIG. 1, the adhesive composition is applied to the first transparent resin film 10, but the present invention is not limited to this, and the adhesive composition is applied to the bonding surface of the second transparent resin film 14. May be. In this case, the first transparent resin film and the second transparent resin film may be exchanged, or the coating device 12 may be installed on the side where the second transparent resin film is conveyed.

  Although the coating method of adhesive composition is not specifically limited, For example, various coating systems, such as a doctor blade, a wire bar, a die coater, a comma coater, a gravure coater, can be utilized. Among these, it is preferable to adopt a gravure roll as the coating device 12 in consideration of thin film coating, the degree of freedom of the pass line, the correspondence to wideness, and the like.

  When a gravure roll is adopted as the coating apparatus 12, the thickness of the adhesive layer can be adjusted by a draw ratio that is a speed ratio of the gravure roll to a line speed. Specifically, the line speed of the first transparent resin film 10 is 15 to 50 m / min, the gravure roll is rotated in the direction opposite to the conveying direction of the first transparent resin film 10, and the rotation speed is 5 to 500 m / min. By adjusting the minute (the draw ratio is 1 to 10), the thickness of the adhesive layer after curing can be adjusted to be about 0.5 to 5 μm.

The 1st transparent resin film 10 and the 2nd transparent resin film 14 are bonded together by the nip roll 13 through the adhesive composition applied in this way. Then, an active energy ray is irradiated by the active energy ray irradiation apparatus 18, and the adhesive composition is cured to form a laminate. The light source used for the irradiation of the active energy ray is not particularly limited, but has a light emission distribution at a wavelength of 400 nm or less, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, microwave excitation A mercury lamp, a metal halide lamp, etc. can be used. The light irradiation intensity of the active energy ray is determined for each target adhesive composition and is not particularly limited. However, the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1. it is preferably ~200mW / cm ^2. When the light irradiation intensity to the adhesive composition is less than 0.1 mW / cm ² , the reaction time tends to be too long, and when it exceeds 200 mW / cm ² , the heat radiated from the lamp and the polymerization of the composition There is a possibility that yellowing of the adhesive composition and deterioration of the transparent resin film may occur due to heat generation at the time.

The irradiation time of the active energy rays to the adhesive composition is controlled for each adhesive composition to be cured, and is not particularly limited. However, the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 It is preferably set to be ˜5,000 mJ / cm ² . When the cumulative amount of light to the adhesive composition is less than 10 mJ / cm ² , the generation of active species derived from the initiator may not be sufficient, and the adhesive composition may be insufficiently cured. When the integrated light quantity exceeds 5,000 mJ / cm ² , the irradiation time becomes very long, which is disadvantageous for improving productivity.

  When ultraviolet rays are used as active energy rays, the line speed of each transparent resin film is not particularly limited, and active energy rays are irradiated to the laminate under a tension of 4 to 30 N / 50 mm width in the longitudinal direction (conveyance direction). It is preferable. Moreover, when the integrated light quantity is insufficient by irradiation of the active energy beam by the active energy beam device 14, a plurality of active energy beam devices are installed, the active energy beam is additionally irradiated, and the adhesive composition of the laminate is polymerized. May be completed.

  The adhesive composition is preferably a solvent-free composition because drying is not necessary. When a solvent is contained in the adhesive composition, a drying furnace may be installed before the first transparent resin film and the second transparent resin film are bonded together, and the solvent may be dried.

  When an adhesive composition in which the adhesive component is dissolved in water or an aqueous adhesive in which the adhesive component is dispersed in water is used as the adhesive composition, the adhesive is used in front of the nip roll 16 instead of the coating device 12. It is preferable to employ a method in which a supply device is installed and the adhesive composition is poured between the films to be bonded. In this case, it is preferable that a drying furnace for removing moisture contained in the adhesive is installed after the nip roll 16 and the film is bonded and then dried. In such a coating method, the thickness of the cured adhesive layer can be made less than 0.5 μm.

  When using an adhesive composition for bonding of the 1st transparent resin film 10 and the 2nd transparent resin film 14, it is preferable to provide a drying furnace after the coating apparatus 12. FIG. Moreover, after these films are bonded together through the pressure-sensitive adhesive composition, UV irradiation by the active energy ray device 14 and / or heating by a drying furnace are performed as necessary to form a laminate 20.

  When the 1st transparent resin film 10 and the 2nd transparent resin film 14 are bonded by an adhesive layer, it is also possible to manufacture the laminated body 20 by another embodiment. Specifically, for example, a pressure-sensitive adhesive layer is formed on a polyethylene terephthalate film that has been subjected to a release treatment, and this is laminated on a first transparent resin film to form a polyethylene terephthalate film / pressure-sensitive adhesive layer / first transparent resin film. Then, the laminate 20 can be manufactured by peeling the polyethylene terephthalate film and bonding the second transparent resin film through the exposed adhesive layer. The transparent resin film on which the polyethylene terephthalate film on which the pressure-sensitive adhesive layer is formed may be the first transparent resin film or the second transparent resin film.

  Next, a 1st bonding process (2), a 1st hardening process (3), a 2nd bonding process (4), and a 2nd hardening process (5) are demonstrated. These steps can be performed by a method similar to the method described in the lamination step (1).

  A 1st bonding process (2) and a 1st hardening process (3) are replaced with a 1st transparent resin film / 2nd instead of a 1st transparent resin film in the lamination process (1) demonstrated above. The laminated body of the transparent resin film is replaced with the second transparent resin film, the polarizing film is replaced with the adhesive composition or the pressure-sensitive adhesive composition forming the second adhesive layer or the pressure-sensitive adhesive layer, and the first adhesion. Each of the agent compositions may be used in the same manner as in the laminating step (1). For the first adhesive composition, an adhesive composition having high solubility of the first transparent resin film is used in order to improve the adhesion of the first transparent resin film by the first adhesive composition. It is preferable. Here, when the first transparent resin film is conveyed alone and coated with a highly soluble first adhesive composition, the first transparent resin film and the polarizing film are bonded before the first transparent resin film is bonded. Although there is a concern that the first transparent resin film may be broken, in the present invention, since the first transparent resin film and the second transparent resin film are laminated in advance, the first transparent resin film is not cut. .

  A 2nd bonding process (4) and a 2nd hardening process (5) can also be produced by the method similar to the lamination | stacking process (1) demonstrated above. That is, in the lamination step (1), the third transparent resin film is replaced with the first transparent resin film, and the polarizing film / first transparent resin film / second transparent resin is replaced with the second transparent resin film. In the same manner as in the laminating step (1), the laminated body of the film is replaced with the adhesive composition or the pressure-sensitive adhesive composition forming the second adhesive layer or the pressure-sensitive adhesive layer, and the third adhesive composition is used. Just do it.

  When laminating the third transparent resin film on the polarizing film, the first bonding step (2) and the second bonding step (4), the first curing step (3) and the second are described above. These curing steps (5) can be performed simultaneously. When carrying out simultaneously, although a transparent resin film will be bonded together on both surfaces of a polarizing film, a 1st transparent resin film and a 2nd transparent resin film are made into a laminated body beforehand, and a 1st transparent resin is made. Compared with the case where the film is used alone, handling properties at the time of conveyance are improved, and wrinkling of the film is less likely to occur at the time of bonding.

  FIG. 2 is a schematic cross-sectional view showing an arrangement example of apparatuses suitable for performing the first bonding step (2) to the second curing step (5). In FIG. 2, for convenience of explanation, the laminate 20 obtained in the laminating step (1) is bonded to one surface of the polarizing film 24, and the third transparent resin film 26 is laminated to the other surface. Although embodiment which manufactures the composite polarizing plate 30 formed was shown, as above-mentioned, the 3rd transparent resin film 26 is provided as needed.

  In FIG. 2, a coating device 22 that applies an adhesive to one side of a laminate 20 of a first transparent resin film / second transparent resin film, and an adhesive is applied to one side of a third transparent resin film 28. The example of the apparatus which provided the coating apparatus 28, the laminated body 20, the nip roll 30 which bonds the polarizing film 24, and the 3rd transparent resin film 26, and the active energy ray irradiation apparatus 32 in order along the conveyance direction was shown. With reference to FIG. 2, first, the laminate 20 is continuously drawn from a feed roll, and the first adhesive composition is applied to the surface on the first transparent resin film side by the coating device 22. In the same manner, the third transparent resin film 26 is continuously fed out from the feeding roll, and the third adhesive composition is applied to the bonding surface with the polarizing film by the coating device 28. Thereafter, the laminate 20 and the third transparent resin film 26 are bonded together by the nip roll 30 via the polarizing film 24 continuously fed from the feed roll and the respective adhesive compositions. Next, active energy rays are irradiated by an active energy ray irradiation device 32 to cure the respective adhesive compositions, whereby a composite polarizing plate 34 made of the laminate 20 / polarizing film 24 / third transparent resin film 26 is manufactured. The The composite polarizing plate 34 may be wound up or may be supplied to the next step in which an adhesive layer is subsequently provided on the surface.

  Examples of the method for applying the adhesive composition, the method for pasting the film, and the method for curing the adhesive include the same method as the above-described method for manufacturing the first transparent resin film / second transparent resin film laminate. Can be mentioned. That is, if necessary, a drying furnace may be installed before and after the film is bonded with a nip roll, or an adhesive supply device may be employed instead of the coating device depending on the type of adhesive employed.

[Polarized film]
Next, the structural member of the composite polarizing plate manufactured by this invention is demonstrated. In the polarizing film, a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin. By uniaxially stretching the polyvinyl alcohol-based resin film before, during or after the adsorption of the dichroic dye, the dichroic dye can be oriented in the stretching direction. The polyvinyl alcohol resin can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, and acrylamides having an ammonium group.

  The degree of saponification of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 mol% or more. This polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal, polyvinyl acetal, polyvinyl butyral and the like modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is usually in the range of 1,000 to 10,000, preferably in the range of 1,500 to 5,000.

  A film obtained by forming such a polyvinyl alcohol resin is used as a raw film of a polarizing film. The method for forming the polyvinyl alcohol-based resin is not particularly limited, and can be formed by a conventionally known appropriate method. Although the film thickness of the raw film which consists of polyvinyl alcohol-type resin is not specifically limited, For example, it is about 10-150 micrometers.

  A polarizing film usually includes a process of dyeing a polyvinyl alcohol resin film with a dichroic dye and adsorbing the dichroic dye (dyeing process), and a polyvinyl alcohol resin film on which the dichroic dye is adsorbed. It is manufactured through a step of treating with an acid aqueous solution (boric acid treatment step) and a step of washing with water after the treatment with the boric acid aqueous solution (water washing treatment step).

  In addition, in the production of the polarizing film, the polyvinyl alcohol-based resin film is uniaxially stretched, but this uniaxial stretching may be performed before the dyeing process, or may be performed during the dyeing process, or the dyeing process. It may be performed after the process. When uniaxial stretching is performed after the dyeing treatment step, this uniaxial stretching may be performed before the boric acid treatment step or during the boric acid treatment step. Of course, it is also possible to perform uniaxial stretching in these plural stages. Uniaxial stretching may be performed by passing between spaced apart rolls having different peripheral speeds, or may be performed by a method of sandwiching with hot rolls. Moreover, the dry-type extending | stretching which extends | stretches in air | atmosphere may be sufficient, and the wet extending | stretching which extends | stretches in the state swollen with the solvent may be sufficient. The draw ratio is usually about 3 to 8 times.

  The polyvinyl alcohol resin film is dyed with a dichroic dye, for example, by immersing the polyvinyl alcohol resin film in an aqueous solution containing the dichroic dye. As the dichroic dye, for example, iodine or a dichroic organic dye is used. Examples of the dichroic organic dye include dichroic direct dyes composed of disazo compounds such as C.I. DIRECT RED 39, and dichroic direct dyes composed of compounds such as trisazo and tetrakisazo. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

  When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water, and the content of potassium iodide is usually 0.5 to 20 parts by weight per 100 parts by weight of water. . When iodine is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is usually 20 to 40 ° C., and the immersion time (dyeing time) in this aqueous solution is usually 20 to 1,800 seconds. .

On the other hand, when a dichroic organic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic organic dye is usually employed. The content of the dichroic organic dye in this aqueous solution is usually 1 × 10 ⁻⁴ to 10 parts by weight, preferably 1 × 10 ⁻³ to 1 part by weight, more preferably 1 × 10 10 per 100 parts by weight of water. ⁻³ to 1 × 10 ⁻² parts by weight. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. When a dichroic organic dye is used as the dichroic dye, the temperature of the aqueous dye solution used for dyeing is usually 20 to 80 ° C., and the immersion time (dyeing time) in this aqueous solution is usually 10 to 1. 800 seconds.

  The boric acid treatment step is performed by immersing a polyvinyl alcohol-based resin film dyed with a dichroic dye in an aqueous boric acid solution. The amount of boric acid in the boric acid aqueous solution is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye in the dyeing process, the aqueous solution used in the boric acid treatment process preferably contains potassium iodide in addition to boric acid. In this case, the content of potassium iodide in the boric acid aqueous solution is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. The immersion time in the boric acid aqueous solution is usually 60 to 1,200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C., more preferably 60 to 80 ° C.

  In the subsequent water washing treatment step, the polyvinyl alcohol-based resin film after the boric acid treatment is washed with water, for example, by immersing it in water. The water temperature in the water washing treatment is usually 5 to 40 ° C., and the immersion time is usually 1 to 120 seconds. After the water washing treatment, usually a drying treatment is performed to obtain a polarizing film. The drying process can be performed using, for example, a hot air dryer or a far infrared heater. The temperature of a drying process is 30-100 degreeC normally, Preferably it is 50-80 degreeC. The time for the drying treatment is usually 60 to 600 seconds, preferably 120 to 600 seconds.

  As described above, it is possible to produce a polarizing film in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol resin film. The thickness of the polarizing film can be about 5 to 40 μm.

[Transparent resin film]
As described above, the transparent resin film of the present invention includes the first transparent resin film laminated on the polarizing film, the second transparent resin film laminated on the first transparent resin film, and the polarizing film. There exists a 3rd transparent resin film laminated | stacked on the surface on the opposite side to the surface bonded by the 1st transparent resin film. Here, the first transparent resin film, the second transparent resin film, and the third transparent resin film may all be the same, may be different from each other, or may be all different. As an example of a transparent resin film, since the same thing can be mentioned also in any transparent resin film, it demonstrates collectively here. In the following description, when it is simply described as “transparent resin film”, the content is common to all the first to third transparent resin films unless otherwise specified.

  As the transparent resin film in the present invention, a resin film composed of an appropriate material widely used as a protective film forming material in this field can be used without particular limitation. Examples of the resin constituting the resin film include cellulose acetate resin, cycloolefin resin, polyolefin resin, acrylic resin, polyimide resin, polycarbonate resin, and polyester resin. Among these, cellulose acetate resin and cycloolefin resin are preferably used.

  Said cellulose acetate type-resin film is a film which consists of a cellulose part or a complete acetate ester, for example, a triacetylcellulose film, a diacetylcellulose film, etc. are mentioned.

  Examples of the cellulose acetate-based resin constituting the cellulose acetate-based resin film include appropriate commercially available products such as “Fujitac TD80”, “Fujitac TD80UF” and “Fujitac TD80UZ” sold by Fuji Film Co., Ltd. A film made of cellulose acetate resin such as “KC2UA”, “KC8UX2M” and “KC8UY” (all are trade names) sold by Konica Minolta Opto Co., Ltd. can be suitably used.

  The cycloolefin-based resin is a thermoplastic resin having a unit of a monomer composed of a cyclic olefin (cycloolefin) such as norbornene or a polycyclic norbornene-based monomer (also called a thermoplastic cycloolefin-based resin). be called). This cycloolefin-based resin may be a hydrogenated product of the above-mentioned cycloolefin ring-opening polymer or a ring-opening copolymer using two or more cycloolefins. It may be an addition polymer with an aromatic compound having a group or the like. Those having a polar group introduced are also effective.

  When a transparent resin film is formed using a copolymer of a cycloolefin, a chain olefin, and an aromatic compound having a vinyl group, examples of the chain olefin include ethylene, propylene, and the like. Examples of the group compound include styrene, α-methylstyrene, and nuclear alkyl-substituted styrene. In such a copolymer, the monomer unit composed of cycloolefin may be 50 mol% or less (preferably 15 to 50 mol%). In particular, when a transparent resin film is formed using a terpolymer of a cycloolefin, a chain olefin, and an aromatic compound having a vinyl group, a monomer unit composed of a cycloolefin is relatively The amount can be small. In such a terpolymer, the monomer unit composed of a chain olefin is usually 5 to 80 mol%, and the monomer unit composed of an aromatic compound having a vinyl group is usually 5 to 80 mol%.

  Cycloolefin-based resins are commercially available as appropriate, for example, “Topas” sold by Ticona, “Arton” sold by JSR Corporation, and “Zeonor” (sold by Nippon Zeon Corporation). ZEONOR ”and“ ZEONEX ”,“ Appel ”(all are trade names) sold by Mitsui Chemicals, Inc., and the like can be preferably used. When such a cycloolefin-based resin is formed into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used. In addition, for example, “Essina” and “SCA40” sold by Sekisui Chemical Co., Ltd., “ZEONOR FILM” (all of which are trade names) sold by Optes Co., Ltd. are formed in advance. A commercially available cycloolefin resin film may be used as the transparent resin film.

  The cycloolefin resin film used as the transparent resin film may be uniaxially stretched or biaxially stretched. In this case, the draw ratio is usually 1.1 to 5 times, preferably 1.1 to 3 times.

  The transparent resin film used for this invention may be comprised by the single layer, and may be comprised by the multilayer. A film composed of multiple layers is produced, for example, by extruding a resin simultaneously during injection molding, and there is no adhesive or pressure-sensitive adhesive between layers. The resin forming the layer may be the same or different.

  The first transparent resin film may have a coating layer made of a liquid crystalline compound, a high molecular weight compound, or the like on the surface opposite to the surface to be bonded to the polarizing film. Further, the second transparent resin film is on the surface opposite to the surface bonded to the first transparent resin film, and the third transparent resin film is the surface opposite to the surface bonded to the polarizing film. Further, surface treatments such as antiglare treatment, hard coat treatment, antistatic treatment, and antireflection treatment may be applied.

  Moreover, the transparent resin film itself may have functionality. As a transparent resin film having functionality, a retardation film that has been stretched in one or more directions and developed a phase difference, or light emitted from a light source is separated into transmitted polarized light and reflected polarized light or scattered polarized light, and reflected polarized light or scattered polarized light. A brightness enhancement film that can improve the emission efficiency by using the recursive light from the backlight.

  The transparent resin film used for the polarizing plate of the present invention is preferably thin, but if it is too thin, the strength is lowered and the processability tends to be inferior. On the other hand, if it is too thick, the transparency tends to decrease or the weight of the polarizing plate tends to increase. From such a viewpoint, the thickness of the first transparent resin film in the polarizing plate of the present invention is usually 5 to 100 μm, preferably 10 to 80 μm, and more preferably 10 to 50 μm.

  As an example of a preferable configuration of the composite polarizing plate in the present invention, the first transparent resin film is a retardation film made of an olefin resin, and the second transparent resin film is laminated on the first transparent resin film. An example is a retardation film having a methacrylic resin layer on the surface, and the third transparent resin film is a transparent resin film made of cellulose acetate. In the composite polarizing plate of the present invention, the first transparent resin film and the second transparent resin film may have the configuration described in Patent Document 2 described above. As described in the same document, such a polarizing plate is less likely to cause local color unevenness even when two retardation films are laminated, and has a viewing angle characteristic when applied to an IPS mode liquid crystal cell. Are better.

[Adhesive layer and pressure-sensitive adhesive layer]
The adhesive layer in the present invention, that is, the first adhesive layer existing between the first transparent resin film and the polarizing film, the second adhesive existing between the first transparent resin film and the second transparent resin film. The layer and the third adhesive layer existing between the third transparent resin film and the polarizing film are each made of a cured product of the adhesive (adhesive composition) used. In the present invention, the first transparent resin film and the second transparent resin film are laminated via the second adhesive layer or the pressure-sensitive adhesive layer. Will be described after.

(Adhesive layer)
First, an adhesive layer used for laminating resin films in the present invention will be described. In the present invention, the first adhesive layer, the second adhesive layer, and the third adhesive layer are respectively the first adhesive composition, the second adhesive composition, and the third adhesive composition. Formed from. These adhesive compositions may be the same or different from each other independently. However, the adhesive compositions forming the first adhesive layer and the third adhesive layer may be the same. preferable. In the following description, when it is simply described as “adhesive composition”, the contents are common to all the first to third adhesive compositions unless otherwise specified.

  The adhesive composition in the present invention is not particularly limited, but a curable resin composition containing an active energy ray-curable compound, an adhesive component dissolved in water, or an adhesive component dispersed in water. Water-based adhesives. Here, the “active energy ray-curable compound” means a compound that can be cured by irradiation with active energy rays. In this invention, since the drying process after bonding is unnecessary, it is preferable to use the curable resin composition containing an active energy ray curable compound.

  The active energy ray-curable compound may be cationically polymerizable or radically polymerizable. Examples of the cationically polymerizable compound include an epoxy compound having at least one epoxy group in the molecule and an oxetane compound having at least one oxetane ring in the molecule. Examples of radically polymerizable compounds include (meth) acrylic compounds having at least one (meth) acryloyloxy group in the molecule. The term “(meth) acryloyloxy group” means that either a methacryloyloxy group or an acryloyloxy group may be used, and “(meth)” when referred to as (meth) acrylate has the same meaning. .

  Among the active energy ray-curable compounds used for the bonding, the first adhesive layer and the third adhesive layer used for bonding with the polarizing film preferably include at least an epoxy compound, whereby the polarizing film And good adhesion between the first transparent resin film and the third transparent resin film.

  From the viewpoint of weather resistance, refractive index, cationic polymerizability, and the like, the epoxy compound preferably contains an epoxy compound containing no aromatic ring in the molecule as a main component. As an epoxy compound which does not contain an aromatic ring in a molecule | numerator, the glycidyl ether of the polyol which has an alicyclic ring, an aliphatic epoxy compound, an alicyclic epoxy compound etc. can be illustrated.

  The glycidyl ether of a polyol having an alicyclic ring is a glycidyl etherification of a nuclear hydrogenated polyhydroxy compound obtained by selectively hydrogenating an aromatic polyol under pressure in the presence of a catalyst. Can be. Examples of the aromatic polyol include bisphenol type compounds such as bisphenol A, bispheel F and bisphenol S; novolak type resins such as phenol novolac resin, cresol novolac resin and hydroxybenzaldehyde phenol novolac resin; tetrahydroxydiphenylmethane, tetrahydroxy Examples thereof include polyfunctional compounds such as benzophenone and polyvinylphenol. Glycidyl ether can be obtained by reacting an alicyclic polyol obtained by hydrogenating the aromatic ring of these aromatic polyols with epichlorohydrin. Among these glycidyl ethers of polyols having an alicyclic ring, hydrogenated bisphenol A diglycidyl ether is preferable.

  The aliphatic epoxy compound can be a polyglycidyl ether of an aliphatic polyhydric alcohol or an alkylene oxide adduct thereof. More specifically, 1,4-butanediol diglycidyl ether; 1,6-hexanediol diglycidyl ether; glycerin triglycidyl ether; trimethylolpropane triglycidyl ether; polyethylene glycol diglycidyl ether; propylene Diglycidyl ether of glycol; diglycidyl ether of neopentyl glycol; adding one or more alkylene oxides (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol or glycerin Polyglycidyl ether of polyether polyol obtained by the above.

Moreover, the monofunctional epoxy compound represented by the following Formula (I) is also mentioned as an aliphatic epoxy compound. In the following formula (I), R ¹ represents an alkyl group having 1 to 15 carbon atoms, and this alkyl group may be linear, or may be branched when it has 3 or more carbon atoms. The alkyl group is preferably a relatively long chain, for example, having 6 or more carbon atoms, and more preferably in the range of 6 to 10 carbon atoms. Of these, a branched alkyl group is preferred. A typical example of the monofunctional epoxy compound represented by the formula (I) is 2-ethylhexyl glycidyl ether.

  An alicyclic epoxy compound is a compound having at least one epoxy group bonded to an alicyclic ring in the molecule. Here, the “epoxy group bonded to the alicyclic ring” means a bridged oxygen atom —O— in the structure represented by the following formula (II), wherein n is an integer of 2 to 5. is there.

A compound in which a group in a form in which one or a plurality of hydrogen atoms in (CH ₂ ) _n in formula (II) are removed is bonded to another chemical structure can be an alicyclic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _n forming the alicyclic ring may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group.

  Among the epoxy compounds as described above, alicyclic epoxy compounds, that is, compounds in which at least one of the epoxy groups is bonded to the alicyclic ring are preferable, and in particular, epoxycyclohexane [in formula (II), n = 3 And epoxycycloheptane (with n = 4 in the above formula (II)), the cured product has a high elastic modulus and gives good adhesion between the polarizing film and the transparent resin film. Therefore, it is more preferably used. Specific examples of the alicyclic epoxy compound are listed below. Here, the compound names are given first, and then the chemical formulas corresponding to each are shown, and the same reference numerals are given to the compound names and the chemical formulas corresponding thereto.

A: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate,
B: 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate,
C: ethylene bis (3,4-epoxycyclohexanecarboxylate),
D: Bis (3,4-epoxycyclohexylmethyl) adipate,
E: bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate,
F: Diethylene glycol bis (3,4-epoxycyclohexyl methyl ether),
G: ethylene glycol bis (3,4-epoxycyclohexyl methyl ether),
H: 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro [5.2.2.2.5.2] henicosane,
I: 3- (3,4-epoxycyclohexyl) -8,9-epoxy-1,5-dioxaspiro [5.5] undecane,
J: 4-vinylcyclohexene dioxide,
K: Limonene dioxide
L: bis (2,3-epoxycyclopentyl) ether,
M: Dicyclopentadiene dioxide and the like.

  In the curable resin composition, the epoxy compound may be used alone or in combination of two or more.

  Further, the curable resin composition may contain an oxetane compound in addition to the epoxy compound. By adding an oxetane compound, the viscosity of the curable resin composition can be lowered and the curing speed can be increased.

The oxetane compound is a compound having at least one oxetane ring (four-membered ether) in the molecule, such as 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3 -Oxetanyl) methoxymethyl] benzene, 3-ethyl-3- (phenoxymethyl) oxetane, di [(3-ethyl-3-oxetanyl) methyl] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane And phenol novolac oxetane. These oxetane compounds can be easily obtained as commercial products. For example, “Aron Oxetane OXT-101” and “Aron Oxetane OXT-” are trade names sold by Toagosei Co., Ltd. 121 ”,“ Aron Oxetane
OXT-211 ”,“ Aron Oxetane OXT-221 ”,“ Aron Oxetane OXT-212 ”, etc. The amount of the oxetane compound is not particularly limited, but it is usually based on the whole active energy ray-curable compound. It is 50 wt% or less, preferably 10 to 40 wt%.

  When the curable resin composition contains a cationically polymerizable compound such as an epoxy compound or an oxetane compound, a photocationic polymerization initiator is usually added to the curable resin composition. When a cationic photopolymerization initiator is used, it is possible to form an adhesive layer at room temperature, so the need to consider the heat resistance and distortion due to expansion of the transparent resin film or polarizing film is reduced, and the transparent resin film has good adhesion. A polarizing film and a transparent resin film can be bonded together. Moreover, since a photocationic polymerization initiator acts catalytically by light, even if this is mixed with a curable resin composition, the curable resin composition is excellent in storage stability and workability.

  The cationic photopolymerization initiator generates a cationic species or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams, and initiates a polymerization reaction of the cationically polymerizable compound. The cationic photopolymerization initiator may be of any type, but specific examples include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-arene complexes, etc. There is.

Examples of the aromatic diazonium salt include the following compounds.
Benzenediazonium hexafluoroantimonate,
Benzenediazonium hexafluorophosphate,
Benzenediazonium hexafluoroborate, etc.

Examples of the aromatic iodonium salt include the following compounds.
Diphenyliodonium tetrakis (pentafluorophenyl) borate,
Diphenyliodonium hexafluorophosphate,
Diphenyliodonium hexafluoroantimonate,
Di (4-nonylphenyl) iodonium hexafluorophosphate and the like.

Examples of the aromatic sulfonium salt include the following compounds.
Triphenylsulfonium hexafluorophosphate,
Triphenylsulfonium hexafluoroantimonate,
Triphenylsulfonium tetrakis (pentafluorophenyl) borate,
4,4'-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate,
4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluoroantimonate,
4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluorophosphate,
7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate,
7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate,
4-phenylcarbonyl-4'-diphenylsulfonio-diphenyl sulfide hexafluorophosphate,
4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenyl sulfide hexafluoroantimonate,
4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenyl sulfide tetrakis (pentafluorophenyl) borate and the like.

Moreover, as an iron-arene complex, the following compounds are mentioned, for example.
Xylene-cyclopentadienyl iron (II) hexafluoroantimonate,
Cumene-cyclopentadienyl iron (II) hexafluorophosphate,
Xylene-cyclopentadienyl iron (II) tris (trifluoromethylsulfonyl) methanide.

These photocationic polymerization initiators can be easily obtained as commercial products. For example, “Kayarad PCI-220” and “Kayarad PCI-620” sold by Nippon Kayaku Co., Ltd. under the trade names, respectively. "UVI-6990" sold by Dow Chemical Co., "UVACURE 1590" sold by Daicel Cytec, and "Adekaoptomer SP-150" sold by ADEKA And “Adekaoptomer SP-170”, “CI-5102”, “CIT-1370”, “CIT-1682”, “CIP-1866S” sold by Nippon Soda Co., Ltd.
“CIP-2048S” and “CIP-2064S”, “DPI-101”, “DPI-102”, “DPI-103”, “DPI-105”, “MPI-103” sold by Midori Chemical Co., Ltd. ”,“ MPI-105 ”,“ BBI-101 ”,
“BBI-102”, “BBI-103”, “BBI-105”, “TPS-101”, “TPS-102”, “TPS-103”,
“TPS-105”, “MDS-103”, “MDS-105”, “DTS-102” and “DTS-103”, “PI-2074” sold by Rhodia, and the like.

  These photocationic polymerization initiators may be used alone or in combination of two or more. Among these, in particular, the aromatic sulfonium salt has an ultraviolet absorption property even in a wavelength region of 300 nm or more, so that it has excellent curability and gives good mechanical strength. Since it can give the hardened | cured material which has the favorable adhesiveness between transparent resin films, it is used preferably.

  The compounding amount of the cationic photopolymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the total of the cationic polymerizable compounds including the epoxy compound and the oxetane compound. is there. If the amount of the cationic photopolymerization initiator is small, curing becomes insufficient, and the mechanical strength and the adhesiveness between the transparent resin films or between the polarizing film and the transparent resin film tend to be reduced. On the other hand, if the amount of the cationic photopolymerization initiator is too large, the ionic substance in the cured product will increase, resulting in an increase in the hygroscopicity of the cured product, and the durability performance of the resulting adhesive layer may decrease. is there.

  The radically polymerizable (meth) acrylic compound is obtained by reacting at least one (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule or two or more compounds having a functional group. And (meth) acrylate oligomers having at least two (meth) acryloyloxy groups in the molecule. These may be used alone or in combination of two or more. When two or more types are used in combination, two or more (meth) acrylate monomers may be used, two or more (meth) acrylate oligomers may be used, and, of course, one or more (meth) acrylate monomers. One or more (meth) acrylate oligomers may be used in combination.

  The above (meth) acrylate monomer includes a monofunctional (meth) acrylate monomer having one (meth) acryloyloxy group in the molecule, and a bifunctional (meth) acrylate having two (meth) acryloyloxy groups in the molecule. ) Acrylate monomers and polyfunctional (meth) acrylate monomers having three or more (meth) acryloyloxy groups in the molecule.

  Specific examples of monofunctional (meth) acrylate monomers include tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. 2-hydroxy-3-phenoxypropyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) Acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, benzyl (meth) acrylate, isobornyl ( (Meth) acrylate, phenoxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, ethyl carbitol (meth) acrylate, trimethylolpropane mono (meth) acrylate, pentaerythritol mono ( And (meth) acrylate and phenoxypolyethylene glycol (meth) acrylate.

  As the monofunctional (meth) acrylate monomer, a carboxyl group-containing (meth) acrylate monomer may be used. Examples of the carboxyl group-containing monofunctional (meth) acrylate monomer include 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, carboxyethyl (meth) acrylate, and 2- (meth). Examples include acryloyloxyethyl succinic acid, N- (meth) acryloyloxy-N ′, N′-dicarboxymethyl-p-phenylenediamine, and 4- (meth) acryloyloxyethyl trimellitic acid.

  N-substituted (meth) acrylamide may be used as the monofunctional (meth) acrylate monomer. N-substituted (meth) acrylamide is (meth) acrylamide having a substituent at the N-position. A typical example of the substituent is an alkyl group which may be further substituted, but may form a ring together with the nitrogen atom of (meth) acrylamide, and this ring is composed of a carbon atom and (meth) In addition to the nitrogen atom of acrylamide, you may have an oxygen atom as a ring member. Further, a substituent such as alkyl or oxo (═O) may be bonded to the carbon atom constituting the ring. N-substituted (meth) acrylamides can generally be prepared by reaction of (meth) acrylic acid or its chloride with a primary or secondary amine.

The N-substituted (meth) acrylamide is particularly preferably the one represented by the following formula (III). In the following formula (III), Q ¹ represents a hydrogen atom or a methyl group, Q ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and Q ³ represents a carbon number that may have a hydroxyl group or an amino group. Represents a 1-6 alkyl group, or Q ² and Q ³ together form a 5-membered or 6-membered ring which may have an oxygen atom as a ring member together with the nitrogen atom to which they are bonded . When Q ² is an alkyl group, and Q ³ is an alkyl group that may have a hydroxyl group or an amino group, each alkyl group may be linear or branched as long as it has 3 or more carbon atoms. Good. An example where Q ³ is an alkyl group having a hydroxyl group is a hydroxyalkyl group. Examples where Q ³ is an alkyl group having an amino group include an aminoalkyl group, an N-alkylaminoalkyl group, and an N, N-dialkylaminoalkyl group. When Q ² and Q ³ together form a 5-membered or 6-membered ring which may have an oxygen atom as a ring member together with the nitrogen atom to which they are bonded, the 5-membered or 6-membered ring An example of a ring in the form of a group leading to carbonyl (C═O) at the N-position is 1-pyrrolidinyl (C ₄ H ₈ N—), 2-oxazolidinon-3-yl (C ₂ H ₄ OC ( = O) N-), N- piperidino (C ₅ H _10), morpholino _{(C 2 H 4 OC 2 H} 4 N-) , and the like.

Specific examples of N-substituted (meth) acrylamides corresponding to formula (III), wherein Q ² is a hydrogen atom and Q ³ is an alkyl group include N-methyl (meth) acrylamide, N-ethyl (meta ) Acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, N-hexyl (meth) acrylamide and the like. Similarly, specific examples of N-substituted (meth) acrylamide in which both Q ² and Q ³ are alkyl groups include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide and the like.

Similarly, as specific examples of N-substituted (meth) acrylamide in which Q ² is a hydrogen atom and Q ³ is an alkyl group having a hydroxyl group, N-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (Meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide and the like. Similarly, as a specific example of N-substituted (meth) acrylamide in which Q ² is a hydrogen atom and Q ³ is an alkyl group having an amino group, N- [2- (N, N-dimethylamino) ethyl] (Meth) acrylamide, N- [2- (N, N-diethylamino) ethyl] (meth) acrylamide, N- [3- (N, N-dimethylamino) propyl] (meth) acrylamide, N- [1-methyl -1- (N, N-dimethylamino) ethyl] (meth) acrylamide.

Further, as a specific example of N-substituted (meth) acrylamide in which Q ² and Q ³ in the formula (III) are combined to form a 5-membered ring or a 6-membered ring with the nitrogen atom to which they are bonded, There are N-acryloylpyrrolidine, 3-acryloyl-2-oxazolidinone, 4-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine and the like.

  Among the N-substituted (meth) acrylamides mentioned above, N-hydroxyalkyl (meth) acrylamides such as N-hydroxymethylacrylamide and N- (2-hydroxyethyl) acrylamide, and N, N-dimethylacrylamide and N, N, N-dialkyl (meth) acrylamide such as N-diethylacrylamide is preferred, and N- (2-hydroxyethyl) acrylamide or N, N-dimethylacrylamide is particularly preferred.

  In addition, N-alkyl (meth) acrylamide having a long chain alkyl such as N-dodecyl (meth) acrylamide, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, and N- (alkoxyalkyl) (meth) acrylamide such as N- (butoxymethyl) acrylamide can also be used as the N-substituted (meth) acrylamide constituting the curable component of the active energy ray-curable resin composition.

  Bifunctional (meth) acrylate monomers include alkylene glycol di (meth) acrylates, polyoxyalkylene glycol di (meth) acrylates, halogen-substituted alkylene glycol di (meth) acrylates, aliphatic polyol di (meth) acrylates Di (meth) acrylates of hydrogenated dicyclopentadiene or tricyclodecane dialkanol, di (meth) acrylates of dioxane glycol or dioxane dialkanol, di (meth) of alkylene oxide adducts of bisphenol A or bisphenol F Representative examples include acrylates, epoxy di (meth) acrylates of bisphenol A or bisphenol F, and the like.

  More specific examples of the bifunctional (meth) acrylate monomer include ethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1 , 6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate, ditri Methylolpropane di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, silicone di (meth) acrylate, di (meth) acrylate of hydroxypivalic acid neopentyl glycol ester, 2,2 -Bis [4- (meth) acryloyloxyethoxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxyethoxyethoxycyclohexyl] propane, hydrogenated dicyclopentadienyl di (meth) acrylate, tricyclo Decanedimethanol di (meth) acrylate, 1,3-dioxane-2,5-diyldi (meth) acrylate [also known as dioxane glycol di (meth) acrylate], hydroxypivalaldehyde and trimethylo Acetal compound with propane [chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane], di (meth) acrylate, tris (hydroxyethyl) ) Isocyanurate di (meth) acrylate.

  The trifunctional or higher polyfunctional (meth) acrylate monomers include glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol. Tri- or higher functional aliphatic polyols such as tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate Poly (meth) acrylates are typical, other poly (meth) acrylates of tri- or higher functional halogen-substituted polyols, alkylene oxyalkylene glycerols. Adduct tri (meth) acrylate, trimethylolpropane alkylene oxide adduct tri (meth) acrylate, 1,1,1-tris [(meth) acryloyloxyethoxyethoxy] propane, tris (hydroxyethyl) isocyanurate Examples include tri (meth) acrylates.

  On the other hand, (meth) acrylate oligomers include urethane (meth) acrylate oligomers, polyester (meth) acrylate oligomers, and epoxy (meth) acrylate oligomers.

  The urethane (meth) acrylate oligomer is a compound having a urethane bond (—NHCOO—) and at least two (meth) acryloyloxy groups in the molecule. Specifically, a urethanization reaction product of a hydroxyl group-containing (meth) acrylate monomer and a polyisocyanate each having at least one (meth) acryloyloxy group and at least one hydroxyl group in the molecule, and a polyol Urethane reaction product of terminal isocyanate group-containing urethane compound obtained by reaction with isocyanate and (meth) acrylate monomer each having at least one (meth) acryloyloxy group and at least one hydroxyl group in the molecule, etc. It can be.

  Examples of hydroxyl group-containing (meth) acrylate monomers used in the urethanization reaction include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenoxy. Examples include propyl (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol penta (meth) acrylate.

  Examples of the polyisocyanate used for the urethanization reaction with the hydroxyl group-containing (meth) acrylate monomer include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and aromatics among these diisocyanates. Diisocyanates obtained by hydrogenating isocyanates (eg, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, etc.), di- or tri-isocyanates such as triphenylmethane triisocyanate, dibenzylbenzene triisocyanate, and the above And polyisocyanate obtained by increasing the amount of diisocyanate.

  In addition, as polyols used to obtain terminal isocyanate group-containing urethane compounds by reaction with polyisocyanates, polyester polyols, polyether polyols, etc., as well as aromatic, aliphatic and alicyclic polyols should be used. Can do. Aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylol ethane, trimethylol propane, ditriol. Examples include methylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, and hydrogenated bisphenol A.

  The polyester polyol is obtained by a dehydration condensation reaction between the above polyols and a polybasic carboxylic acid or an anhydride thereof. Examples of polybasic carboxylic acids or anhydrides thereof can be represented by adding “(anhydrous)” to those that may be anhydrides, and are represented by (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, (anhydrous) Itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, hexahydro (anhydrous) phthalic acid, etc.

  The polyether polyol may be a polyoxyalkylene-modified polyol obtained by a reaction of the above-described polyols or dihydroxybenzenes with an alkylene oxide, in addition to the polyalkylene glycol.

  The polyester (meth) acrylate oligomer is a compound having an ester bond and at least two (meth) acryloyloxy groups in the molecule. Specifically, it can be obtained by a dehydration condensation reaction using (meth) acrylic acid, polybasic carboxylic acid or anhydride thereof, and polyol. Examples of polybasic carboxylic acids or anhydrides thereof used in the dehydration condensation reaction can be represented by adding “(anhydrous)” to those that can be anhydrides. (Anhydrous) succinic acid, adipic acid, (anhydrous) There are maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, hexahydro (anhydrous) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like. Examples of the polyol used for the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, Examples include ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, and hydrogenated bisphenol A.

  The epoxy (meth) acrylate oligomer can be obtained by addition reaction of polyglycidyl ether and (meth) acrylic acid, and has at least two (meth) acryloyloxy groups in the molecule. Examples of the polyglycidyl ether used for the addition reaction include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bisphenol A diglycidyl ether.

  When the curable resin composition contains a radical polymerizable compound such as the (meth) acrylic compound as described above, a photo radical polymerization initiator is preferably blended. Any radical photopolymerization initiator may be used as long as it can initiate polymerization of a radical polymerizable compound such as a (meth) acrylic compound by irradiation with active energy rays, and a conventionally known one can be used. Specific examples of the photoradical polymerization initiator include acetophenone, 3-methylacetophenone, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1 -[4- (methylthio) phenyl-2-morpholinopropan-1-one and acetophenone-based initiators such as 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone, And benzophenone initiators such as 4,4'-diaminobenzophenone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; xanthone, fluorenone , Kanfu Kinon, benzaldehyde, there is such as anthraquinone.

  The compounding quantity of radical photopolymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of radically polymerizable compounds, such as a (meth) acrylic-type compound, Preferably it is 1-6 weight part. When there are few compounding quantities of radical photopolymerization initiator, hardening will become inadequate and it exists in the tendency for the adhesive strength of mechanical strength and transparent resin films, or a polarizing film and a transparent resin film to fall. Moreover, when there are too many compounding quantities of radical photopolymerization initiator, radicals, such as an active energy ray curable compound (a cation polymerizable curable compound containing an epoxy compound, and a (meth) acrylic compound) in a curable resin composition, are included. There is a possibility that the durability of the resulting adhesive layer is lowered due to relatively less polymerizable compound).

  Moreover, the curable resin composition may use the above-mentioned epoxy compound or the epoxy compound and the oxetane compound together with the radically polymerizable (meth) acrylic compound. By using these in combination, the effect of increasing the hardness and mechanical strength of the adhesive layer can be expected, and furthermore, the adjustment of the viscosity and curing rate of the curable resin composition can be more easily performed.

  The curable resin composition can further contain a photosensitizer as necessary. By adding a photosensitizer, the reactivity of cationic polymerization and / or radical polymerization is increased, and the mechanical strength of the adhesive layer and the adhesiveness between the transparent resin films or between the polarizing film and the transparent resin film are improved. Can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreductive dyes. More specific examples of photosensitizers include benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether and α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, o-benzoyl Benzophenone derivatives such as methyl benzoate, 4,4'-bis (dimethylamino) benzophenone and 4,4'-bis (diethylamino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; 2-chloro Anthraquinone derivatives such as anthraquinone and 2-methylanthraquinone; acridone derivatives such as N-methylacridone and N-butylacridone; other α, α-diethoxyacetophenone, benzyl, fluo There are renon, xanthone, uranyl compounds, halogen compounds and the like. These photosensitizers may be used alone or in combination of two or more. The photosensitizer is preferably blended at a ratio of 0.1 to 20 parts by weight based on 100 parts by weight of the entire active energy ray-curable compound.

  In the curable resin composition, a known polymer additive usually used for polymers can be added. For example, primary antioxidants such as phenols and amines, sulfur secondary antioxidants, hindered amine light stabilizers (HALS), UV absorbers such as benzophenone, benzotriazole, or benzoate Is mentioned.

  Furthermore, the curable resin composition may contain a solvent as needed. The solvent is appropriately selected in consideration of the solubility of the components constituting the curable resin composition. Examples of common solvents include aliphatic hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; such as methanol, ethanol, propanol, isopropanol and n-butanol Alcohols; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as methyl acetate, ethyl acetate and butyl acetate; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; methylene chloride and chloroform Such as halogenated hydrocarbons. The mixing ratio of the solvent is appropriately determined from the viewpoint of adjusting the viscosity depending on the processing purpose such as film formability.

  Examples of the water-based adhesive in which the adhesive component is dissolved in water or the adhesive component is dispersed in water include an adhesive composition using a polyvinyl alcohol resin or a urethane resin as a main component.

  When using a polyvinyl alcohol-based resin as the main component of the water-based adhesive, the polyvinyl alcohol-based resin is not only partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, but also carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, It may be a modified polyvinyl alcohol resin such as methylol group-modified polyvinyl alcohol or amino group-modified polyvinyl alcohol. When a polyvinyl alcohol resin is used as the adhesive component, the adhesive is often prepared as an aqueous solution of a polyvinyl alcohol resin. The density | concentration of the polyvinyl alcohol-type resin in an adhesive agent is about 1-10 weight part normally with respect to 100 weight part of water, Preferably it is 1-5 weight part.

  A water-based adhesive mainly composed of a polyvinyl alcohol resin can contain a crosslinking agent. The cross-linking agent may be a compound having a functional group having reactivity with a polyvinyl alcohol resin, and those conventionally used in polyvinyl alcohol adhesives can be used without particular limitation. When compounds capable of forming a crosslinking agent are listed by functional group, an isocyanate compound having at least two isocyanato groups (—NCO) in the molecule; an epoxy compound having at least two epoxy groups (crosslinked —O—) in the molecule; Mono- or di-aldehydes; organic titanium compounds; inorganic salts of divalent or trivalent metals such as magnesium, calcium, iron, nickel, zinc, and aluminum; metal salts of glyoxylic acid; methylol melamine;

  When a urethane resin is used as the main component of the water-based adhesive, examples of a suitable adhesive composition include a mixture of a polyester ionomer-type urethane resin and a compound having a glycidyloxy group. The polyester-based ionomer type urethane resin here is a urethane resin having a polyester skeleton, into which a small amount of an ionic component (hydrophilic component) is introduced. Such an ionomer type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier and becomes an emulsion. Polyester ionomer urethane resins are known per se. For example, Japanese Patent Application Laid-Open No. 7-97504 describes a polyester ionomer type urethane resin as an example of a polymer dispersant for dispersing a phenol resin in an aqueous medium. JP-A-2005-070140 and JP-A-2005-181817 describe a polarizing film made of a polyvinyl alcohol resin using a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group as an adhesive. The form which joins a cycloolefin system resin film is shown.

  In the present invention, the solubility of each transparent resin film by each adhesive composition is preferably higher from the viewpoint of adhesion between the films, but a plurality of adhesives between the first transparent resin film and the polarizing film are laminated. In particular, it is preferable that the first transparent resin film is highly soluble by the first adhesive composition used for the first adhesive layer because it is necessary to sufficiently adhere the film and the polarizing film.

  The solubility of the transparent resin film by the first adhesive composition is such that the first transparent resin is applied after the first adhesive composition is applied in a state where tension is applied to the first transparent resin film. The time until the film is cut is evaluated. Specifically, the first transparent resin film is cut with a width of 50 mm in a direction (TD) perpendicular to the transport direction of the first transparent resin film at the time of manufacture, and the end of the transport direction (MD) is cut with a jig. Clamp and apply 18N tension. The length in the MD direction at this time is arbitrary. Thereafter, the first adhesive composition is applied to the adhesive-coated surface, and the time until the first transparent resin film is cut is measured. The shorter this time, the higher the solubility of the first transparent resin film by the first adhesive composition and the higher the adhesion. In the present invention, as the first adhesive composition, the time from the contact of the first transparent resin film and the first adhesive composition to the cutting of the first transparent resin film is 120 seconds. Although what is below is used, this time is more preferably 60 seconds or less, and further preferably 30 seconds or less.

  In the present invention, the thickness of the adhesive layer after drying or curing is usually about 0.01 to 5 μm, but can be 1 μm or less when an aqueous adhesive is used. On the other hand, even when an adhesive made of a curable resin composition containing an active energy ray-curable compound is used, it is preferably 3 μm or less. If the adhesive layer is too thin, the adhesion may be insufficient. On the other hand, if the adhesive layer is too thick, the appearance of the polarizing plate may be poor.

(Adhesive layer)
Next, the adhesive layer used for lamination | stacking of a 1st transparent resin film and a 2nd transparent resin film is demonstrated. When an adhesive is used for laminating the first transparent resin film and the second transparent resin film, an acrylic polymer, silicone polymer, polyester, polyurethane, polyether, or the like is used as the base polymer for the adhesive. Things can be used. Above all, like acrylic pressure-sensitive adhesives, it has excellent optical transparency and adhesiveness, retains appropriate wettability and cohesion, and has weather resistance, heat resistance, etc. under conditions of heating and humidification It is preferable to select and use a material that does not cause peeling problems such as floating and peeling. In acrylic adhesives, alkyl esters of (meth) acrylic acid having an alkyl group having 20 or less carbon atoms such as methyl, ethyl and butyl groups, and (meth) acrylic acid and hydroxyethyl (meth) acrylate An acrylic copolymer having a weight average molecular weight of 100,000 or more, in which a glass transition temperature is preferably 25 ° C. or less, more preferably 0 ° C. or less Useful as a base polymer.

  The pressure-sensitive adhesive layer is formed, for example, by dissolving or dispersing the pressure-sensitive adhesive composition including the above-mentioned base polymer in an organic solvent such as toluene or ethyl acetate to prepare a 10 to 40% by weight solution, and protecting film The pressure-sensitive adhesive layer can be formed on the transparent resin film by forming a pressure-sensitive adhesive layer on the transparent resin film. In addition to the base polymer described above, a crosslinking agent is generally added to the adhesive. Furthermore, when bonding to a liquid crystal cell is intended, it is also preferable to mix a silane coupling agent. The thickness of the pressure-sensitive adhesive layer is determined according to the adhesive force and the like, but is usually in the range of 1 to 50 μm.

  The pressure-sensitive adhesive may be blended with fillers made of glass fiber, glass beads, resin beads, inorganic powders such as metal powder, pigments, colorants, antioxidants, ultraviolet absorbers, and the like as necessary. . Examples of ultraviolet absorbers include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.

<Active energy ray-curable compound>
“Celoxide 2021P”: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, obtained from Daicel Chemical Industries, Ltd.
“EX-214L”: 1,4-butanediol diglycidyl ether, obtained from Nagase ChemteX Corporation.
“EX-121”: 2-ethylhexyl glycidyl ether, obtained from Nagase ChemteX Corporation.
“EX-211”: Neopentyl glycol diglycidyl ether, obtained from Nagase ChemteX Corporation.
“HEAA”: N- (2-hydroxyethyl) acrylamide, obtained from Kojin Co., Ltd.

<Photocationic polymerization initiator>
“Adekaoptomer SP-150”: 4,4′-bis [diphenylsulfonio] diphenyl sulfide A photocationic polymerization initiator based on bishexafluorophosphate, obtained from ADEKA Co., Ltd. in the form of a propylene carbonate solution.
“Irgacure 907”: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, obtained from BASF Japan Ltd.

<Other ingredients>
“SH710”: Silicone leveling agent, obtained from Toray Dow Corning Co., Ltd.

[Manufacturing Example 1] Preparation of Adhesive Compositions A to C The following components are mixed to form an adhesive composition A corresponding to the first and third adhesive compositions, and a comparative adhesive composition B. The adhesive composition C corresponding to the second adhesive composition was prepared. In addition, although the photocationic polymerization initiator “Adekaoptomer SP-150” is a propylene carbonate solution, the following is indicated by the amount of the active ingredient.

<Adhesive composition A>
“Celoxide 2021P” 60 parts “EX-214L” 30 parts “EX-121” 10 parts “Adekaoptomer SP-150” 2.25 parts “SH710” 0.2 parts

<Adhesive composition B>
“Celoxide 2021P” 85 parts “EX-211” 15 parts “Adekaoptomer SP-150” 2.25 parts “SH710” 0.2 parts

<Adhesive composition C>
“HEAA” 80 parts Methyl acrylate 20 parts “Irgacure 907” 3 parts “SH710” 0.2 part

  About said adhesive composition A and B, the solubility of the transparent resin film was confirmed. As the transparent resin film, an amorphous polyolefin resin film having a thickness of 15 μm (trade name “Arton” from JSR Co., Ltd.) was used, and this was made into a piece of 200 mm × 50 mm so that the conveyance direction of the film was the long side. Cutting and fixing the end in the transport direction with a jig, 18N tension was applied. When the adhesive composition A prepared in Production Example 1 was applied to the surface so that the thickness after curing was 2 μm, the film was cut in 4 seconds. On the other hand, when the adhesive composition B was applied in the same manner, the film was not cut even after 180 seconds or longer.

[Production Example 2] Production of retardation film having methacrylic resin layer The styrene-maleic anhydride copolymer sold by Nova Chemical Japan Co., Ltd. under the trade name “Dylark D332” and having a glass transition temperature of 131 ° C. Polymerized resin was used. A methacrylic resin having a glass transition temperature of 105 ° C., which is used for “Technoloy S001” sold by Sumitomo Chemical Co., Ltd. and contains about 20% of acrylic rubber particles having an average particle diameter of 200 μm. Then, three-layer coextrusion is performed on both sides of the layer made of styrene-maleic anhydride copolymer resin so that a layer made of methacrylic resin is formed, and a layer made of styrene-maleic anhydride copolymer resin A transparent resin film having a three-layer structure was prepared in which the thickness of the methacrylic resin layer formed on both sides thereof was 14 μm. This three-layer transparent resin film is stretched to have a layer made of styrene-maleic anhydride copolymer resin having a thickness of 11 μm, a methacrylic resin layer having a thickness of 7 μm, and a total thickness of 25 μm. A retardation film having a methacrylic resin layer was prepared and used as a second transparent resin film.

  The Example and comparative example which manufactured the composite polarizing plate using said adhesive composition and retardation film are shown. As the first transparent resin film, an amorphous polyolefin resin film having a thickness of 15 μm [trade name “Arton” from JSR Co., Ltd.] was used as a third transparent resin film, and a 25 μm-thick triacetyl cellulose film [ Konica Minolta Opto's trade name “KC2UA”] was used.

[Example 1]
(Production of laminate of first transparent resin film / second transparent resin film)
On one side of a retardation film having a methacrylic resin layer produced in Production Example 2, the adhesive composition C produced in Production Example 1 is applied to a coating apparatus [product name “Microchamber Doctor” of Fuji Machine Industry Co., Ltd.] Was used for coating. The line speed is 20 m / min, the gravure roll is rotated in the direction opposite to the film transport direction, and the gravure roll speed is 20 m / min, so that the thickness of the cured adhesive layer is about 1 μm. Coated. Next, the retardation film having the methacrylic resin layer was overlapped with the amorphous polyolefin resin film with a nip roll through the adhesive composition C.

Next, ultraviolet rays irradiated from two EHAN1700NAL high-pressure mercury lamps, which are ultraviolet lamps provided in an ultraviolet irradiation device manufactured by GS Yuasa Corporation, are conveyed with a tension of 400 N in the longitudinal direction of the film. The adhesive composition C was cured to obtain a laminate. In the ultraviolet irradiation, the cumulative amount of ultraviolet light was set to 200 mJ / cm ² from the amorphous polyolefin resin film side of the laminate. The integrated light quantity of ultraviolet rays was measured based on irradiation in the UVB region having a wavelength range of 280 to 320 nm.

(Manufacture of composite polarizing plate)
Next, a composite polarizing plate was produced by laminating the above laminate on one side of the polarizing film and the above-mentioned 25 μm thick triacetylcellulose film on the other side through the adhesive composition A, respectively. First, the adhesive composition A produced in Production Example 1 was applied to one side of the above-mentioned triacetyl cellulose film and the non-crystalline polyolefin resin film of the laminate. The coating was made using the name “Microchamber Doctor”]. At this time, the thickness of the adhesive layer after curing is set such that the line speed of the laminate is 15 m / min, the gravure roll is rotated in the direction opposite to the conveying direction of the laminate, and the gravure roll speed is 30 m / min. The coating was carried out so as to be about 2 μm. Subsequently, these films were bonded to each other with a nip roll on a polyvinyl alcohol film having a thickness of 12 μm adsorbed and oriented through the adhesive composition A. At this time, the laminate was not broken.

A 400N tension is applied to the laminated body in the longitudinal direction of the film in the ultraviolet rays irradiated from two EHAN1700NAL high-pressure mercury lamps, which are ultraviolet lamps provided in an ultraviolet irradiation device manufactured by GS Yuasa Corporation. Then, the adhesive composition A was cured. In the ultraviolet irradiation, the integrated light amount of ultraviolet light was set to 250 mJ / cm ² from the transparent resin film laminate side. The integrated light quantity of ultraviolet rays was measured based on irradiation in the UVB region having a wavelength range of 280 to 320 nm. Thus, the composite polarizing plate which consists of a retardation film which has a triacetyl cellulose film / polarizing film / amorphous polyolefin resin film / methacrylic resin layer was manufactured.

<Evaluation of adhesive strength>
The retardation film surface having the methacrylic resin layer of the composite polarizing plate produced above was subjected to corona treatment, and then an acrylic pressure-sensitive adhesive sheet was bonded to the corona-treated surface. The obtained composite polarizing plate with pressure-sensitive adhesive was cut into a test piece having a width of 25 mm and a length of about 200 mm, and the pressure-sensitive adhesive surface was bonded to soda glass, and then the pressure was 5 kgf / cm ² and the temperature was 50 ° C. using an autoclave. And a pressure treatment for 20 minutes, and further allowed to stand for 1 day in an atmosphere at a temperature of 23 ° C. and a relative humidity of 60%. In this state, using a universal tensile testing machine ["AG-1" manufactured by Shimadzu Corporation], grab the triacetylcellulose film and polarizing film at one end in the length direction of the test piece (width of 25 mm), 90 ° Peel Test (JIS K 6854-1: 1999 “Adhesive-Peeling Adhesive Strength Test Method-No. 1” at a cross head speed (gripping speed) of 200 mm / min in an atmosphere of 23 ° C. and 60% relative humidity. Part: 90 degree peeling ”), and the adhesive force between the amorphous polyolefin resin film and the polarizing film was evaluated to be 1.2 N / 25 mm.

[Example 2]
It carried out similarly to Example 1 except having used the 15-micrometer-thick acrylic adhesive for bonding of the retardation film which has an amorphous polyolefin resin film and a methacrylic-type resin layer. In this step, there was no cutting of the film. Moreover, when the adhesive force between an amorphous polyolefin resin film and a polarizing film was evaluated, it was 1.1 N / 25mm.

[Comparative Example 1]
Production of the polarizing plate, without producing a laminate of the first transparent resin film / second transparent resin film, a triacetyl cellulose film on one side of the polarizing film, an amorphous polyolefin resin film on the other side, It carried out by the method of bonding through the adhesive composition A, respectively. The adhesive composition A produced in Production Example 1 was applied to each bonding surface of the triacetyl cellulose film and the amorphous polyolefin resin film by a coating apparatus [product name “Microchamber Doctor” of Fuji Machine Industry Co., Ltd.] ] Was used for coating. At this time, the thickness of the adhesive layer after curing is set such that the line speed of the laminate is 15 m / min, the gravure roll is rotated in the direction opposite to the conveying direction of the laminate, and the gravure roll speed is 30 m / min. The coating was carried out so as to be about 2 μm. Next, these films were bonded to a polyvinyl alcohol film having a thickness of 12 μm adsorbed and oriented through the adhesive composition A using a nip roll. The film was cut and the polarizing plate could not be produced. For this reason, the measurement of the adhesive force between an amorphous polyolefin resin film and a polarizing film was not implemented.

[Comparative Example 2]
The adhesive composition B produced in Production Example 1 was applied to one side of each of the triacetyl cellulose film and the amorphous polyolefin resin film, and the coating apparatus [product name “Microchamber Doctor” of Fuji Machine Industry Co., Ltd.] Was used for coating. The thickness of the adhesive layer after curing is about 2 μm by setting the line speed of the laminate to 15 m / min, rotating the gravure roll in the direction opposite to the conveying direction of the laminate and setting the gravure roll speed to 30 m / min. It was coated so that Subsequently, these films were bonded to each other with a nip roll on a polyvinyl alcohol film having a thickness of 12 μm adsorbed and oriented via the adhesive composition B. Here, although the amorphous polyolefin was not cut, wrinkles were generated in a part of the amorphous polyolefin resin film at the time of bonding.

  Thereafter, an acrylic pressure-sensitive adhesive layer and a retardation film having a methacrylic resin layer prepared in Production Example 2 were sequentially bonded to the surface of the amorphous polyolefin resin film to obtain a composite polarizing plate. It was 0.2 N / 25mm when the adhesive force between the amorphous polyolefin resin film and polarizing film of the obtained polarizing plate was evaluated.

  From Example and Comparative Example 1, by using a laminate in which a first transparent resin film and a second transparent resin film are laminated in advance, even when an adhesive composition having high film solubility is used, during transportation No cutting occurred in the film. On the other hand, it can be seen from Comparative Example 2 that when an adhesive composition having low solubility in the film is used, the adhesive strength is reduced although the film is not cut during conveyance. Further, in Comparative Example 2, wrinkles were generated at the time of pasting, whereas in Examples 1 and 2, no wrinkles were generated. Therefore, the first transparent resin film / the second transparent resin film was laminated. By using the body, it is considered that handling is improved as compared with the case of using a single layer film, and the generation of wrinkles is suppressed.

10: First transparent resin film,
12, 22, 28 ... coating equipment,
14 …… Second transparent resin film,
16, 30 ... nip roll,
18, 32 ... Active energy ray irradiation device,
20 …… Laminate,
24 …… Polarizing film,
26 …… Third transparent resin film,
34. Composite polarizing plate.

Claims (7)

A first transparent resin film is laminated on a polarizing film made of a polyvinyl alcohol-based resin via a first adhesive layer formed from the first adhesive composition, and the first transparent resin film is further coated with a first transparent resin film. A method for producing a composite polarizing plate in which a second transparent resin film is laminated via an adhesive layer or an adhesive layer of 2,
The polarizing film, the first transparent resin film, and the second transparent resin film are laminated while being conveyed in a long shape,
The first transparent resin film and the first adhesive composition are formed on the first transparent resin film by applying a tension of 18 N / 50 mm width in the transport direction of the first transparent resin film alone. When the first adhesive composition is applied, the time until the first transparent resin film is cut has a relationship of 120 seconds or less,
The method
A laminating step of laminating the first transparent resin film and the second transparent resin film via the second adhesive layer or the pressure-sensitive adhesive layer;
A first bonding step of bonding the polarizing film to the first transparent resin film via the first adhesive composition; and the first adhesive composition by curing the first adhesive composition. The manufacturing method of the composite polarizing plate characterized by including the 1st hardening process which forms an agent layer, and performing in this order.   The method for producing a composite polarizing plate according to claim 1, wherein the first adhesive composition is cured by irradiation with active energy rays. In the composite polarizing plate, the first transparent resin film and the second transparent resin film are laminated in this order on one surface of the polarizing film, and a third adhesive composition is formed on the other surface of the polarizing film. A third transparent resin film is laminated via a third adhesive layer formed from
The method further comprises:
A second bonding step in which the third transparent resin film is bonded to the polarizing film via the third adhesive composition; and the third adhesive composition is cured to cure the third adhesive. The manufacturing method of the composite polarizing plate of Claim 1 or 2 provided with the 2nd hardening process which forms an agent layer.   The composite polarizing plate production according to claim 3, wherein the first bonding step and the second bonding step are performed simultaneously, and the first curing step and the second curing step are performed simultaneously. Method.   The method for producing a composite polarizing plate according to claim 3 or 4, wherein the third adhesive composition is cured by irradiation with active energy rays.   The method for producing a composite polarizing plate according to claim 1, wherein the first transparent resin film is a retardation film made of an olefin resin.   The composite polarized light according to any one of claims 1 to 6, wherein the second transparent resin film is a retardation film having a methacrylic resin layer on the side laminated on the first transparent resin film. A manufacturing method of a board.

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