JP6567931B2 - Method for producing laminated optical film - Google Patents

Description

  The present invention relates to a method for producing a laminated optical film.

  A polarizing plate which is a kind of laminated optical film constitutes a liquid crystal display device. A polarizing plate is equipped with the polarizer which is 1 type of an optical film, and the protective film laminated | stacked on the single side | surface or both surfaces of the polarizer. Patent Document 1 below discloses forming a transparent resin layer by coating a resin solution on one or both surfaces of a polarizing film. When it is necessary to protect an optical film other than the polarizer, the laminated optical film includes a resin layer that overlaps the optical film.

JP 2000-199819 A

  In recent years, with the thinning of mobile devices such as smartphones, it has been required to thin laminated optical films used for mobile devices. One way to thin the laminated optical film is to overlay a thinner protective layer on the optical film instead of a conventional protective film. For example, when manufacturing a polarizing plate, using a coating apparatus such as a gravure roll, forming a coating film containing an active energy ray-curable resin on the surface of the polarizer, and curing this coating film with active energy rays It is easy to form a protective layer (resin layer) thinner than a conventional protective film. However, when the coating film is applied to the surface of the polarizer, the coating apparatus comes into contact with the polarizer and damages the surface of the polarizer. Such a problem may also occur when a protective layer is formed on the surface of an optical film other than the polarizer. That is, when the coating apparatus damages the surface of the optical film, the optical function of the optical film is impaired. In addition, the protective layer (resin layer) formed on the surface of the polarizer may also be damaged by contact with a roll or the like during subsequent processes or during transportation.

  This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the laminated optical film which can suppress the damage of the resin layer surface which overlaps with the optical film surface and an optical film.

A method for producing a laminated optical film according to one aspect of the present invention includes a coating step of forming a coating film containing an active energy ray-curable resin on a surface of a film-like substrate that has not been subjected to corona treatment , A curing step in which the material is bonded to the surface of the optical film via the coating film, an active energy ray is irradiated from the substrate side to the coating film, and a resin layer is formed from the coating film; It includes a peeling step of peeling the substrate from the resin layer, the transmittance of the active energy ray in the substrate state, and are 70% or more, the substrate is a cyclic polyolefin resin or an acrylic resin, a resin layer Is a protective layer for protecting the optical film.

  In one aspect of the present invention, the active energy ray may be ultraviolet light.

  In one aspect of the present invention, the active energy ray-curable resin may be at least one selected from the group consisting of epoxy resins, acrylic resins, and oxetane resins.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the lamination | stacking optical film which can suppress the damage of the resin film surface which overlaps with the optical film surface and an optical film is provided.

FIG. 1 is a schematic view showing a method for producing a polarizing plate according to the first embodiment of the present invention. (A) in FIG. 2, (b) in FIG. 2, and (c) in FIG. 2 are schematic views showing a method for producing a polarizing plate according to the first embodiment of the present invention. FIG. 3 is a schematic view showing a method for producing a polarizing plate according to the second embodiment of the present invention. (A) in FIG. 4, (b) in FIG. 4, and (c) in FIG. 4 are schematic views showing a method for producing a polarizing plate according to the second embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals. The present invention is not limited to the following embodiment.

(First embodiment)
1st embodiment is related with the manufacturing method of the polarizing plate which is 1 type of a laminated optical film. The manufacturing method of the polarizing plate which concerns on 1st embodiment is provided with a coating process, a bonding process, and a hardening process at least. In the coating process, a coating film containing the active energy ray-curable resin is formed on the surface of the film-like substrate. In the bonding step, the substrate is bonded to the surface of the optical film via the coating film. In the curing step, the active energy ray is irradiated onto the coating film from the substrate side to form a resin layer from the coating film. Below, each process is demonstrated in detail.

[Coating process]
As shown to (a) in FIG.1 and FIG.2, the 1st laminated body 24 is used in the coating process of 1st embodiment. The first laminate 24 includes a film-like polarizer 38, an adhesive layer 36 that overlaps the polarizer 38, and a protective film 34 that is bonded to the polarizer 38 through the adhesive layer 36.

  The film-like polarizer 38 may be produced, for example, by the following procedure.

  First, a film-like polyvinyl alcohol-based resin is stretched in a uniaxial direction or a biaxial direction. Subsequently, the polyvinyl alcohol resin is dyed with iodine or a dichroic dye. The polyvinyl alcohol resin after dyeing is treated with a solution of a crosslinking agent (for example, an aqueous solution of boric acid) for crosslinking. After the treatment with the crosslinking agent, the polyvinyl alcohol-based resin is washed with water and subsequently dried. Through the above procedure, a polarizer 38 is obtained. The polyvinyl alcohol resin can be obtained by saponifying a polyvinyl acetate resin. The polyvinyl acetate resin is, for example, polyvinyl acetate, which is a homopolymer of vinyl acetate, or a copolymer of vinyl acetate and another monomer (for example, ethylene-vinyl acetate copolymer). Good. Other monomers that copolymerize with vinyl acetate may be unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, or acrylamides with ammonium groups in addition to ethylene. The polyvinyl alcohol resin may be modified. The modified polyvinyl alcohol resin may be, for example, polyvinyl formal modified with aldehydes, polyvinyl acetal, or polyvinyl butyral.

  The thickness of the polarizer 38 may be 10 μm or less, or 8 μm or less. The thinner the polarizer 38, the easier it is to make the polarizing plate thinner. The thickness of the polarizer 38 may be 2 μm or more. The thicker the polarizer 38, the easier it is to improve the mechanical strength of the polarizer 38.

  The protective film 34 has a function of protecting the polarizer 38. The protective film 34 may be a light-transmitting thermoplastic resin and may be an optically transparent thermoplastic resin. The resin constituting the protective film 34 is, for example, a chain polyolefin resin, a cyclic polyolefin resin, a cellulose ester resin, a polyester resin, a polycarbonate resin, a (meth) acrylic resin, a polystyrene resin, or a mixture thereof. Or it may be a copolymer.

  The chain polyolefin resin may be a homopolymer of a chain olefin such as a polyethylene resin or a polypropylene resin. The chain polyolefin resin may be a copolymer composed of two or more chain olefins.

  The cyclic polyolefin resin may be, for example, a ring-opening (co) polymer of a cyclic olefin or an addition polymer of a cyclic olefin. The cyclic polyolefin resin may be, for example, a copolymer (for example, a random copolymer) of a cyclic olefin and a chain olefin. The chain olefin constituting the copolymer may be, for example, ethylene or propylene. The cyclic polyolefin resin may be a graft polymer obtained by modifying the above polymer with an unsaturated carboxylic acid or a derivative thereof, or a hydride thereof. The cyclic polyolefin resin may be a norbornene resin using a norbornene monomer such as norbornene or a polycyclic norbornene monomer.

  The cellulose ester resin may be, for example, cellulose triacetate (triacetyl cellulose), cellulose diacetate, cellulose tripropionate, or cellulose dipropionate. These copolymers may be used. A cellulose ester resin in which a part of the hydroxyl group is modified with another substituent may be used.

  Polyester resins other than cellulose ester resins may be used. The polyester resin may be, for example, a polycondensate of a polyvalent carboxylic acid or derivative thereof and a polyhydric alcohol. The polyvalent carboxylic acid or derivative thereof may be a dicarboxylic acid or derivative thereof. The polyvalent carboxylic acid or derivative thereof may be, for example, terephthalic acid, isophthalic acid, dimethyl terephthalate, or dimethyl naphthalenedicarboxylate. The polyhydric alcohol may be, for example, a diol. The polyhydric alcohol may be, for example, ethylene glycol, propanediol, butanediol, neopentyl glycol, or cyclohexanedimethanol.

  The polyester resin may be, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, or polycyclohexanedimethyl naphthalate. .

  The polycarbonate-based resin is a polymer in which polymerized units (monomers) are bonded via a carbonate group. The polycarbonate resin may be a modified polycarbonate having a modified polymer skeleton, or may be a copolymerized polycarbonate.

  (Meth) acrylic resin is, for example, poly (meth) acrylic acid ester (for example, polymethyl methacrylate); methyl methacrylate- (meth) acrylic acid copolymer; methyl methacrylate- (meth) acrylic acid ester Polymer; methyl methacrylate-acrylic ester- (meth) acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (for example, MS resin); having methyl methacrylate and alicyclic hydrocarbon group It may be a copolymer with a compound (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.).

  The protective film 34 may include at least one additive selected from the group consisting of a lubricant, a plasticizer, a dispersant, a heat stabilizer, an ultraviolet absorber, an infrared absorber, an antistatic agent, and an antioxidant.

  The thickness of the protective film 34 may be 90 μm or less, 50 μm or less, or 30 μm or less. The thinner the protective film 34, the easier it is to make the polarizing plate thinner. The thickness of the protective film 34 may be 5 μm or more. The thicker the protective film 34 is, the easier it is to improve the mechanical strength and handleability of the protective film 34.

  The protective film 34 may be a film having an optical function, such as a retardation film or a brightness enhancement film. For example, a retardation film to which an arbitrary retardation value is given can be obtained by stretching a film made of the thermoplastic resin or forming a liquid crystal layer or the like on the film.

  The adhesive layer 36 may include an aqueous adhesive such as polyvinyl alcohol, and may include an active energy ray curable resin described later. The thickness of the cured adhesive layer 36 may be, for example, 0.05 μm or more and 10 μm or less. As the adhesive layer 36 is thicker, bubbles are less likely to be formed between the polarizer 38 and the protective film 34, and the polarizer 38 and the protective film 34 are more easily bonded firmly. The thinner the adhesive layer 36, the easier it is to make the polarizing plate thinner.

  As shown to (a) in FIG.1 and FIG.2, in the coating process of 1st embodiment, using the coating apparatus 1, the coating film 32a containing active energy ray curable resin is made into film-form base | substrate. It is formed on the surface of the material 22a. That is, in the coating process, the second laminated body 22b including the base material 22a and the coating film 32a formed on the surface of the base material 22a is produced. The coating apparatus 1 may be a gravure coater such as a micro chamber doctor, for example. The coating film 32a may consist only of active energy ray-curable resin. As described above, since the coating film 32a is formed not on the surface of the polarizer 38 but on the surface of the substrate 22a, the coating apparatus 1 does not directly contact the surface of the polarizer 38. Therefore, there is no damage on the surface of the polarizer 38 due to contact with the coating apparatus 1.

The transmittance of the active energy ray in the base material 22a is 70% or more. The active energy ray may be, for example, ultraviolet light, visible light, electron beam, or X-ray. The transmittance of the active energy ray in the base material 22a may be 75% or more, 76.7% or more, 80% or more, or 89% or more. The transmittance of the active energy rays in the base material 22a may be 95% or less, 99% or less, or less than 100%. In addition, the transmittance | permeability haze of the active energy ray in the base material 22a may be defined as (I / I ₀ ) × 100, for example. I ₀ is the radiation divergence of the active energy ray incident on the base material 22a. I ₀ is the radiant divergence of the active energy ray that has passed through the substrate 22a.

  The transmittance of active energy rays in the base material 22a can be measured using, for example, an ultraviolet-visible gold-infrared spectrophotometer “V-7100” manufactured by JASCO Corporation.

  The active energy ray may be ultraviolet light. The base material 22a having an ultraviolet transmittance of 70% or more may include at least one selected from the group consisting of a cyclic polyolefin resin, a polypropylene resin, an acrylic resin, and a polyethylene resin, for example.

  The cyclic polyolefin resin may be, for example, a ring-opening (co) polymer of a cyclic olefin or an addition polymer of a cyclic olefin. The cyclic polyolefin resin may be, for example, a copolymer (for example, a random copolymer) of a cyclic olefin and a chain olefin. The chain olefin constituting the copolymer may be, for example, ethylene or propylene. The cyclic polyolefin resin may be a graft polymer obtained by modifying the above polymer with an unsaturated carboxylic acid or a derivative thereof, or a hydride thereof. The cyclic polyolefin resin may be a norbornene resin using a norbornene monomer such as norbornene or a polycyclic norbornene monomer.

  Acrylic resin ((meth) acrylic resin) is, for example, poly (meth) acrylic acid ester (for example, polymethyl methacrylate); methyl methacrylate- (meth) acrylic acid copolymer; methyl methacrylate- (meta ) Acrylate ester copolymer; Methyl methacrylate-Acrylate ester- (Meth) acrylic acid copolymer; (Meth) acrylate methyl-styrene copolymer (for example, MS resin); Methyl methacrylate and alicyclic It may be a copolymer with a compound having a hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl copolymer (meth) acrylate).

  The active energy ray-curable resin is a resin that cures when irradiated with active energy rays. The active energy ray-curable resin may be a kind of resin and may include a plurality of kinds of resins.

  When the active energy ray is ultraviolet light, the active energy ray curable resin is an ultraviolet curable resin. The ultraviolet curable resin can be prepared as a solventless adhesive. Therefore, when the active energy ray curable resin is an ultraviolet curable resin, the drying step for removing the solvent may not be performed after the coating step, the bonding step, or the curing step. Further, the ultraviolet curable resin is easy to use in combination with a protective film having a low moisture permeability as compared with the water-based adhesive.

  The ultraviolet curable resin may contain a cationic polymerizable curable compound or a radical polymerizable curable compound. The ultraviolet curable resin may contain a cationic polymerization initiator or a radical polymerization initiator for initiating the curing reaction of the curable compound.

  The cationically polymerizable curable compound may be, for example, an epoxy resin (a compound having at least one epoxy group in the molecule) or an oxetane resin (a compound having at least one oxetane ring in the molecule). The radical polymerizable curable compound may be, for example, a (meth) acrylic resin (a compound having at least one (meth) acryloyloxy group in the molecule). The radical polymerizable curable compound may be a vinyl resin having a radical polymerizable double bond.

  The active energy ray curable resin may be a cationic polymerization accelerator, an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, or an antifoaming agent, if necessary. Agents, antistatic agents, leveling agents, or solvents.

  The active energy ray may be an ultraviolet A wave (UVA). The ultraviolet A wave is ultraviolet light having a wavelength of 400 to 315 nm. The resin constituting the base material 22a having an ultraviolet A wave transmittance of 70% or more may be, for example, a cyclic polyolefin resin, a polypropylene resin, or an acrylic resin. The active energy ray-curable resin (ultraviolet curable resin) that is cured by irradiation with ultraviolet A waves may be, for example, an epoxy resin, an acrylic resin, or an oxetane resin. The active energy ray may be an ultraviolet B wave (UVB). The ultraviolet B wave is an ultraviolet ray having a wavelength of 315 to 280 nm. The resin constituting the base material 22a having an ultraviolet B wave transmittance of 70% or more may be, for example, a cyclic polyolefin resin, a polypropylene resin, or an acrylic resin. The active energy ray-curable resin (ultraviolet curable resin) that is cured by irradiation with ultraviolet B waves may be, for example, an epoxy resin, an acrylic resin, or an oxetane resin. The active energy ray may be an ultraviolet C wave (UVC). The ultraviolet C wave is an ultraviolet ray having a wavelength of less than 280 nm. A resin having an ultraviolet C wave transmittance of 70% or more may be used for the base material 22a.

  The active energy ray may be visible light. A resin having a visible light transmittance of 70% or more may be used for the base material 22a.

  For example, when the active energy ray is ultraviolet light using a high-pressure mercury lamp as a light source, the wavelength of the ultraviolet light is 300 nm, and the base material 22a is made of a cyclic polyolefin resin film or a polypropylene resin film, The transmittance of the active energy ray is 89%. In this case, the active energy ray-curable resin that is cured by irradiation with active energy rays is, for example, an epoxy resin. For example, when the active energy rays are ultraviolet rays using a high-pressure mercury lamp as a light source, the wavelength of the ultraviolet rays is 300 nm, and the substrate 22a is made of an acrylic resin film, the transmittance of the active energy rays in the substrate 22a is 76.7%. In this case, the active energy ray-curable resin that is cured by irradiation with active energy rays is, for example, an epoxy resin.

  The thickness of the base material 22a may be, for example, 5 μm or more and 100 μm or less. The thinner the substrate 22a, the higher the transmittance of active energy rays in the substrate 22a. The thicker the base material 22a, the lower the transmittance of active energy rays in the base material 22a.

[Bonding process]
As shown to (a) in FIG.1 and FIG.2, the 1st laminated body 24a is conveyed along the direction d24, and is supplied between a pair of bonding rolls (roll 7a and 7b). The guide roll 5 a is in contact with the surface of the protective film 34 included in the first laminate 24. Moreover, the 2nd laminated body 22b is conveyed along the direction d22, and is supplied between a pair of rolls 7a and 7b. The guide roll 5b is in contact with the surface of the base material 22a included in the second laminate 22b.

  As shown to (a) and (b) in FIG.1 and FIG.2, in the bonding process, the coating film 32a of the 2nd laminated body 22b is made to oppose the polarizer 38 of the 1st laminated body 24, and the 1st The stacked body 24 and the second stacked body are stacked. The overlapped first laminate 24 and second laminate 22b are sandwiched between a pair of rolls 7a and 7b. In other words, the base material 22a is bonded to the surface of the polarizer 38 through the coating film 32a using a pair of bonding rolls. As a result, the base material 22a, the coating film 32a overlapping the base material 22a, the polarizer 38 overlapping the coating film 32a, the adhesive layer 36 overlapping the polarizer 38, and the protective film 34 overlapping the adhesive layer 36 are provided. The 3rd laminated body 26a provided is obtained.

[Curing process and peeling process]
As shown in FIG. 1, the 3rd laminated body 26a is conveyed along the direction d26 from between a pair of rolls 7a and 7b. In the curing step, the active energy ray L is irradiated to the coating film 32a from the substrate 22a side using the irradiation device 3. That is, the active energy ray L is indirectly irradiated to the coating film 32a through the base material 22a. That is, the active energy ray L passes through the base material 22a and reaches the coating film 32a. By the irradiation with the active energy ray L, the coating film 32a is cured to become the resin layer 32b.

  The irradiation device 3 may be, 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, a microwave excitation mercury lamp, or a metal halide lamp.

  A peeling step may be performed after the curing step. As shown in FIGS. 1 and 2 (b) and (c), in the peeling step, the base material 22a is peeled from the resin layer 32b of the third laminate 26a. In the peeling step, the guide roll 5c contacts the base material 22a included in the third stacked body 26a. The 4th laminated body 26b from which the base material 22a was peeled is conveyed in the direction d26.

  When the peeling step is performed, the polarizing plate does not include the base material 22a. The polarizing plate (fourth laminated body 26b) completed through the peeling step includes a resin layer 32b, a polarizer 38 that directly overlaps the resin layer 32, and an adhesive layer 36, as shown in FIG. And a protective film 34 bonded to the polarizer 38 via the. Moreover, as long as the base material 22a becomes unnecessary in a post process, it is not necessary to peel the base material 22a. By the base material 22a protecting the resin layer 32b, it is possible to suppress the generation of scratches and irregularities on the surface of the resin layer 32b.

  The resin layer 32 b may be a protective layer that protects the polarizer 38. The resin layer 32b may be an optical compensation layer (OC layer). The polarizing plate (fourth laminated body 26b) may include another optical layer laminated on the protective film 34 or the resin layer 32b. Other optical layers include, for example, a reflective polarizing film, a film with antiglare function, a film with antireflection function, a reflective film, a transflective film, a viewing angle compensation film, a hard coat layer, an adhesive layer, and a touch sensor layer. It may be an antistatic layer or an antifouling layer.

  In the curing step, since the transmittance of the active energy ray L in the base material 22a is 70% or more, the coating film 32a is more uniform than in the case where the transmittance of the active energy ray L in the base material is less than the lower limit value. It is easy to cure sufficiently. As a result, the resin layer 32b having a high hardness and hardly scratched is formed. Therefore, even when the base material 22a is peeled from the resin layer 32b, a part of the resin layer 32b or uncured resin is difficult to adhere to the surface of the base material 22a after peeling. That is, it is suppressed that the surface of the resin layer 32b that has been in contact with the base material 22a is damaged as the base material 22a is peeled off. For the above reasons, damage to the resin layer 32b overlapping the film-like polarizer 38 (optical film) is suppressed.

  When performing a peeling process, you may form the coating film 32a in the surface of the base material 22a which has not been roughened in a coating process. When the roughening treatment is applied to the base material 22a, the coating film 32a is likely to be in close contact with the surface of the base material 22a, and the base material 22a is difficult to peel off from the cured coating film 32a (resin layer 32b). Further, when the surface roughening treatment is performed on the base material 22a, the surface of the resin layer 32b in contact with the base material 22a may be damaged as the base material 22a is peeled off. Therefore, by forming the coating film 32a on the surface of the base material 22a that has not been subjected to the roughening treatment, the base material 22a is easily peeled off from the resin layer 32b in the peeling step, and the surface of the resin layer 32b is damaged. It is suppressed. The surface roughening treatment may be, for example, plasma treatment, corona treatment, ultraviolet irradiation treatment, or flame treatment (flame treatment).

  The peeling process may not be performed. When not performing a peeling process, you may give a roughening process to the surface of the base material 22a before a coating process. In the subsequent coating process, the coating film 32a may be formed on the surface of the roughened substrate 22a. As a result, the base material 22a becomes difficult to peel from the resin layer 32b. When the peeling process is not performed, the completed polarizing plate is attached to the polarizer 38 via the base material 22a, the resin layer 32b overlapping the base material, the polarizer 38 overlapping the resin layer 32, and the adhesive layer 36. And a combined protective film 34. The base material 22 a may function as a film that protects the polarizer 38. The polarizing plate may include another optical layer laminated on the base material 22a.

(Second embodiment)
The manufacturing method of the polarizing plate which concerns on 2nd embodiment of this invention is the same as 1st embodiment except the matter described below. Also in the second embodiment, similarly to the first embodiment, damage to the resin layer 32b overlapping the polarizer 38 (optical film) is suppressed. Hereinafter, descriptions of matters common to the first embodiment and the second embodiment are omitted.

  The manufacturing method of the polarizing plate which concerns on 2nd embodiment is equipped with a coating process, a bonding process, and a hardening process at least similarly to 1st embodiment. However, in the coating process of the second embodiment, a coating film is formed on the surface of each of the pair of base materials. In the bonding step of the second embodiment, a film-like polarizer is disposed between a pair of substrates. And a pair of base material is bonded on both surfaces of a polarizer through a coating film. In the curing step of the second embodiment, a pair of resin layers sandwiching the polarizer are formed by irradiating the coating film with active energy rays from the respective sides of the pair of base materials. These steps will be described in detail below.

  As shown to (a) in FIG.3 and FIG.4, in the coating process of 2nd embodiment, using the coating apparatus 1a, the coating film 54a containing active energy ray curable resin is made into film-form base | substrate. Formed on the surface of the material 44a to produce a laminate 44b. The laminated body 44b of the second embodiment may be the same as the second laminated body 22b of the first embodiment. In the coating process, the coating device 1b is used to form the coating film 52a containing the active energy ray-curable resin on the surface of the film-like base material 42a to produce the laminate 42b. The laminated body 42b of the second embodiment may be the same as the second laminated body 22b of the first embodiment. The composition of the coating film 54a of the laminate 44b may be the same as that of the coating film 52a of the laminate 42b. The composition of the coating film 54a of the laminate 44b may be different from the coating film 52a of the laminate 42b. The composition of the base material 44a of the stacked body 44b may be the same as that of the base material 42a of the stacked body 42b. The composition of the base material 44a of the laminate 44b may be different from the base material 42a of the laminate 42b. As described above, since the coating film 52a is formed not on the surface of the polarizer 38 but on the surface of the base material 42a, the coating apparatus 1b does not directly contact the surface of the polarizer 38. Moreover, since the coating film 54a is formed not on the surface of the polarizer 38 but on the surface of the substrate 44a, the coating apparatus 1a does not directly contact the surface of the polarizer 38. Accordingly, there is no damage on both surfaces of the polarizer 38 due to contact with the coating apparatuses 1a and 1b.

  As shown in FIG. 3, in 2nd embodiment, the laminated body 44b is conveyed along the direction d44, and is supplied between a pair of bonding rolls (roll 7c and 7d). The guide roll 5d is in contact with the surface of the base material 44a included in the stacked body 44b. Moreover, the laminated body 42b is conveyed along the direction d42, and is supplied between the rolls 7c and 7d. The guide roll 5e is in contact with the surface of the base material 42a included in the stacked body 42b. Moreover, the film-like polarizer 38 is supplied between the rolls 7c and 7d.

  As shown to (a) and (b) in FIG.3 and FIG.4, in the bonding process of 2nd embodiment, the polarizer 38 is pinched | interposed between a pair of laminated bodies 44b and 42b. The coating film 54 a of the laminate 44 b faces one surface of the polarizer 38. The coating film 52a of the laminate 42b faces the other surface of the polarizer 38. Then, the stacked body 44b, the polarizer 38, and the stacked body 42b are overlapped and sandwiched between a pair of rolls 7c and 7d. As a result, as shown in FIG. 4B, the base material 44a is bonded to one surface of the polarizer 38 through the coating film 54a, and the base material 42a is passed through the coating film 52a. , And bonded to the other surface of the polarizer 38. That is, in the bonding step, the base material 42a, the coating film 52a overlapping the base material 42a, the polarizer 38 overlapping the coating film 52a, the coating film 54a overlapping the polarizer 38, and the base material 44a overlapping the coating film 54a. And a laminated body 46a comprising:

  As shown in FIG. 4, in 2nd embodiment, the laminated body 46 is conveyed along the direction d46 from between a pair of rolls 7c and 7d. In the curing step, the coating device 54a is cured by indirectly irradiating the coating material 54a with the active energy ray L from the side of the substrate 44a using the irradiation device 3a. That is, the active energy ray L passes through the base material 44a and reaches the coating film 54a. At the same time, using the irradiation device 3b, the active energy ray L is indirectly irradiated from the substrate 42a side to the coating film 52a to cure the coating film 52a. That is, the active energy ray L passes through the base material 42a and reaches the coating film 52a. Through the above curing process, the resin layer 52b is formed from the coating film 52a, and the resin layer 54b is formed from the coating film 54a.

  As shown to (b) and (c) in FIG.3 and FIG.4, in 2nd embodiment, you may implement a peeling process after a hardening process. In the peeling step, the base material 44a is peeled from the resin layer 54b of the laminated body 46a. In the peeling step, the guide roll 5f is in contact with the base material 44a included in the stacked body 46a. In the peeling process, the base material 42a is peeled from the resin layer 52b of the laminate 46a. In the peeling step, the guide roll 5g is in contact with the base material 42a included in the stacked body 46a. The laminated body 46b from which the base materials 42a and 44a have been peeled is conveyed in the direction d46.

  When the peeling process is performed, the polarizing plate does not include the base material 42a or 44a. For example, the polarizing plate completed through the peeling process may include at least the resin layer 52b, the polarizer 38 that directly overlaps the resin layer 52b, and another resin layer 54b that directly overlaps the polarizer 38. . The polarizing plate may include another optical layer laminated on the resin layer 52b or 54b. Further, the base material 42a or 44a may not be peeled off unless the base material 42a or 44a becomes unnecessary in a subsequent process. Since the base material 42a protects the resin layer 52b, it is possible to suppress the generation of scratches and irregularities on the surface of the resin layer 52b. By the base material 44a protecting the resin layer 54b, it is possible to suppress the generation of scratches and irregularities on the surface of the resin layer 54b.

  When carrying out the peeling step, the base materials 42a and 44a that have not been subjected to the roughening treatment may be used in the coating step.

  In 2nd embodiment, you may peel only either one of the base materials 42a or 44a in a peeling process. When only one of the base materials 42a or 44a is peeled off, a base material that has been subjected to a roughening treatment may be used in the coating process as the base material on the side that does not peel off. In the second embodiment, the peeling process may not be performed. In the case where the peeling step is not performed, a base material that has been subjected to a roughening treatment may be used in the coating step. Substrates 42a and 44a are arranged on the outer surface of the polarizing plate completed without performing the peeling step. The polarizing plate may include another optical layer laminated on the base material 42a or 44a.

  As mentioned above, although 1st embodiment and 2nd embodiment of this invention were described, this invention is not limited to the said embodiment at all.

  For example, the optical film on which the resin layer is formed may be other optical layers instead of the polarizer. For example, in the same manner when a resin layer is formed on the surface of a polarizer, a protective film, a reflective polarizing film, a film with an antiglare function, a film with a surface antireflection function, a reflective film, a transflective film, a viewing angle A resin layer may be formed on the surface of an optical layer such as a compensation film, a touch sensor layer, or a liquid crystal layer.

  Hereinafter, although the content of the present invention is explained in detail using an example and a comparative example, the present invention is not limited to the following examples.

[Example 1]
(1) Primer layer formation process Polyvinyl alcohol powder was melt | dissolved in 95 degreeC hot water, and the polyvinyl alcohol aqueous solution with a density | concentration of 3 weight% was prepared. As the polyvinyl alcohol powder, “Z-200” (average polymerization degree 1100, saponification degree 99.5 mol%) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. was used. A crosslinking agent was mixed in the polyvinyl alcohol aqueous solution. The addition amount of the crosslinking agent was adjusted to 5 parts by weight with respect to 6 parts by weight of the polyvinyl alcohol powder. As the cross-linking agent, “SUMIREZ RESIN 650” manufactured by Taoka Chemical Co., Ltd. was used. Through the above steps, a primer layer forming coating solution (coating solution 1) was obtained.

  An unstretched polypropylene film (melting point: 163 ° C.) having a thickness of 90 μm was prepared as a base film. One side of the substrate film was subjected to corona treatment. The coating liquid 1 was apply | coated to the surface of the base film to which the corona treatment was performed using the small diameter gravure coater. The primer layer was formed by drying the coating liquid 1 apply | coated to the base film at 80 degreeC for 10 minute (s). The thickness of the primer layer was 0.2 μm.

(2) Production of laminated film (resin layer forming step)
Polyvinyl alcohol powder was dissolved in hot water at 95 ° C. to prepare a polyvinyl alcohol aqueous solution having a concentration of 8% by weight. As the polyvinyl alcohol powder, “PVA124” (average polymerization degree 2400, saponification degree 98.0 to 99.0 mol%) manufactured by Kuraray Co., Ltd. was used. This aqueous polyvinyl alcohol solution was used as a coating liquid (coating liquid 2) for forming a polyvinyl alcohol-based resin layer.

  The coating liquid 2 was apply | coated to the surface of the primer layer formed in the base film using the lip coater. The coating liquid 2 applied on the surface of the primer layer was dried at 80 ° C. for 20 minutes to form a polyvinyl alcohol-based resin layer on the primer layer. The laminated film which consists of a base film, the primer layer which overlaps with a base film, and the polyvinyl alcohol-type resin layer which overlaps with a primer layer was obtained by the above process.

(3) Production of stretched film (stretching process)
The free end uniaxial stretching of the 5.3 times laminated film was performed at 160 ° C. to obtain a stretched film. A floating vertical uniaxial stretching apparatus was used for stretching the laminated film. The thickness of the stretched polyvinyl alcohol resin layer was 5.0 μm.

(4) Production of polarizing laminated film (dyeing process)
The stretched film was immersed in an aqueous solution (dyeing solution) of iodine and potassium iodide for about 180 seconds to dye the polyvinyl alcohol resin layer. The temperature of the staining solution was adjusted to 30 ° C. The weight of iodine in the staining solution was adjusted to 0.6 parts by weight per 100 parts by weight of water. The weight of potassium iodide in the staining solution was adjusted to 10 parts by weight per 100 parts by weight of water. After the dyeing treatment, the excess dyeing solution was washed away from the polyvinyl alcohol resin layer using 10 ° C. pure water.

  In the subsequent first crosslinking treatment, the stretched film was immersed in an aqueous solution containing boric acid (first crosslinking solution) for 120 seconds. The temperature of the first crosslinking liquid was adjusted to 78 ° C. The weight of boric acid in the first crosslinking liquid was adjusted to 9.5 parts by weight per 100 parts by weight of water.

  In the subsequent second crosslinking treatment, the stretched film was immersed in an aqueous solution (second crosslinking solution) containing boric acid and potassium iodide for 60 seconds. The temperature of the second cross-linking liquid was adjusted to 70 ° C. The weight of boric acid in the second crosslinking liquid was adjusted to 9.5 parts by weight per 100 parts by weight of water. The weight of potassium iodide in the second crosslinking liquid was adjusted to 4 parts by weight per 100 parts by weight of water.

  After the second crosslinking treatment, the stretched film was washed with pure water at 10 ° C. for 10 seconds. The stretched film after washing was dried at 40 ° C. for 300 seconds.

  By the above process, the polarizing laminated film which consists of a base film and a film-form polarizer which overlaps with a base film was obtained.

(5) Production of Polarizer with Protective Film A film made of a triacetyl cellulose resin was prepared as the first protective film. The thickness of the first protective film was 25 μm. The first protective film is disposed on the outer side (opposite to the display cell) when the polarizing plate is disposed on the display cell.

  The surface of the first protective film was subjected to corona treatment. An ultraviolet curable adhesive was applied to the surface of the first protective film subjected to the corona treatment to form a first adhesive layer. As the ultraviolet curable adhesive, “KR-70T” manufactured by ADEKA Corporation was used. A small-diameter gravure coater was used for application of the ultraviolet curable adhesive.

  The first protective film was bonded to the surface of the polarizer of the polarizing laminate film via the first adhesive layer. A pair of bonding rolls was used for bonding the first protective film.

Next, the first adhesive layer was cured by irradiating the first adhesive layer with ultraviolet rays from the polarizing laminated film side using a high-pressure mercury lamp. The thickness of the 1st adhesive bond layer after hardening was 1.2 micrometers. The integrated amount of ultraviolet light was adjusted to 200 mJ / cm ² .

  Through the above steps, the base film, the polarizer overlapping the base film, the first adhesive layer overlapping the polarizer, and the first protective film bonded to the polarizer via the first adhesive layer A laminated body consisting of was obtained. By peeling the substrate film from the laminate, the polarizer, the first adhesive layer overlapping the polarizer, and the first protective film bonded to the polarizer via the first adhesive layer are formed. A polarizer with a protective film was obtained.

(6) Production of polarizing plate (Coating process)
In order to form the protective layer, an epoxy resin which is a kind of active energy ray curable resin (ultraviolet curable resin) was prepared. The protective layer is disposed on the display cell side when the polarizing plate is disposed on the display cell. As the epoxy resin, “KR-25T” manufactured by ADEKA Corporation was used. A film made of a cyclic polyolefin resin film was prepared as a transfer substrate. The thickness of the transfer substrate was 20 μm. Using a small-diameter gravure coater, an epoxy resin was applied to the surface of the substrate to form a coating film made of the epoxy resin on the surface of the substrate.

(Bonding process)
The transfer substrate was bonded to the surface of the polarizer constituting the polarizer with a protective film via the coating film. A pasting roll was used for pasting.

(Curing process)
Using a high-pressure mercury lamp, the coating film was irradiated with ultraviolet rays (active energy rays) from the transfer substrate side. The coating film was cured by ultraviolet irradiation to form a resin layer. The integrated light quantity of the ultraviolet rays irradiated on the transfer substrate was adjusted to 200 mJ / cm ² . The wavelength of the ultraviolet light was 300 nm. Table 1 below shows the transmittance of ultraviolet rays in the transfer substrate. The thickness of the resin layer was 3.5 μm.

(Peeling process)
After the curing step, the transfer substrate was peeled from the resin layer.

  Example 1 provided with the resin layer, the polarizer overlapped with the resin layer, the first adhesive layer, and the first protective film bonded to the polarizer through the first adhesive layer by the above steps. A polarizing plate was prepared.

[Examples 1 to 3, Comparative Example 1]
Except having used the transfer base material shown in following Table 1, it carried out similarly to Example 1, and produced each Example and Comparative Example 1 each polarizing plate. Table 1 below shows the transmittance of ultraviolet rays in the transfer substrates used in the other Examples and Comparative Example 1.

[Comparative Example 2]
In the coating process of Comparative Example 2, an epoxy resin was directly applied to the surface of the polarizer constituting the polarizer with a protective film using a small diameter gravure coater to form a coating film.

  In the curing process of Comparative Example 2, the coating film formed on the surface of the polarizer was directly irradiated with ultraviolet rays to form a resin layer on the surface of the polarizer.

  As described above, a polarizing plate of Comparative Example 2 was produced in the same manner as in Example 1 except that the resin layer was formed without using a transfer substrate.

<Observation of the surface of the resin layer>
The polarizing plate of Example 1 was cut to prepare a sample. The sample dimensions were 500 mm × 500 mm. The sample was placed under a fluorescent lamp, and light was applied to the surface of the resin layer included in the sample. A reflection image of light on the surface of the resin layer was observed. The results of observation are shown in Table 1 below.

  In the same manner as in Example 1, the surfaces of the resin layers in other Examples and Comparative Examples were observed. The results of observation are shown in Table 1 below. A in Table 1 below means that no scratches or irregularities were found on the surface of the resin layer. B means that irregularities were found on the surface of the resin layer. C means that the surface of the resin layer was scratched.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to manufacture the laminated | multilayer optical film which can suppress the damage of the resin film surface which overlaps with the optical film surface and an optical film.

  38 ... Polarizer (optical film), 32a, 52a, 54a ... coating film, 32b, 52b, 54b ... resin layer (protective layer), 22a, 42a, 44a ... base material, L ... active energy ray.

Claims (3)

A coating step that forms a coating film containing an active energy ray-curable resin on the surface of the film-like substrate that has not been subjected to corona treatment ; and
A laminating step of laminating the base material on the surface of the optical film via the coating film,
A curing step of irradiating the coating film with active energy rays from the substrate side to form a resin layer from the coating film,
A peeling step of peeling the base material from the resin layer;
With
Transmittance of the active energy ray in said substrate, der 70% is, the substrate is a cyclic polyolefin resin or an acrylic resin,
The resin layer is a protective layer that protects the optical film.
A method for producing a laminated optical film. The active energy ray is ultraviolet light;
The method for producing a laminated optical film according to claim 1. The active energy ray-curable resin is at least one selected from the group consisting of epoxy resins, acrylic resins and oxetane resins,
The manufacturing method of the laminated | multilayer optical film of Claim 1 or 2 .

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