JP6741440B2 - Laminated optical film manufacturing method and laminated optical film manufacturing apparatus - Google Patents

Description

The present invention relates to a laminated optical film manufacturing method and a laminated optical film manufacturing apparatus.

A polarizing plate, which is a type of laminated optical film, constitutes a liquid crystal display device. The polarizing plate includes, for example, a polarizer that is a type of optical film and another optical film (for example, a protective film) that overlaps the polarizer. As described in Patent Document 1 below, a conventional method for manufacturing a polarizing plate includes a step of sandwiching two optical films that overlap with each other with an active energy ray-curable resin (adhesive) between a pair of rolls, and bonding them together. After the laminating step, an irradiation step of irradiating the resin interposed between the two optical films with an active energy ray is provided.

JP, 2013-92766, A

When the plurality of bonded optical films are conveyed between the bonding step and the irradiation step, the end portions of the optical films may be deformed in a wavy shape. In addition, the optical film during transportation may be loosened. Further, the optical film being conveyed may be curved in its width direction (direction substantially perpendicular to the conveying direction). Since the resin before the irradiation step is not cured, the optical film that overlaps with the resin is peeled or floated due to the deformation, slack, or curvature as described above. Such peeling of the optical film causes defects in the laminated optical film such as a polarizing plate.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a laminated optical film capable of suppressing peeling of films after laminating films, and an apparatus for producing a laminated optical film. And

A method for manufacturing a laminated optical film according to one aspect of the present invention includes a laminating step of laminating a plurality of films overlapping with an active energy ray-curable resin with a pair of rolls, and laminating a plurality of films, and laminating. An irradiation step of irradiating active energy rays toward a pair of rolls from which the plurality of formed films are delivered. The individual films used in the laminating step may be a single optical film, or may be a plurality of optical films (a laminate of optical films) already laminated in another step. .. The optical film may be referred to as an optical layer.

The manufacturing apparatus for a laminated optical film according to one aspect of the present invention, sandwiching a plurality of films that overlap with each other through an active energy ray-curable resin, a pair of rolls for bonding the plurality of films, and the plurality of bonded films. An irradiation device that irradiates an active energy ray toward a pair of rolls that are fed.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a laminated optical film and the manufacturing apparatus of a laminated optical film which can suppress peeling of a film after bonding films are provided.

FIG. 1 is a schematic diagram showing a method for manufacturing a laminated optical film (polarizing plate) according to the first embodiment of the present invention, and a manufacturing apparatus used for the manufacturing method. FIG. 2 is an enlarged view of the vicinity of a pair of rolls included in the manufacturing apparatus shown in FIG. FIG. 3 is a modification of the pair of rolls shown in FIG. (A) in FIG. 4, (b) in FIG. 4, and (c) in FIG. 4 are schematic views showing a method for producing a laminated optical film according to the first embodiment of the present invention. FIG. 5: is a schematic diagram which shows the manufacturing method used for the manufacturing method of the laminated optical film which concerns on 2nd embodiment of this invention, and the said manufacturing method. (A) in FIG. 6 and (b) in FIG. 6 are schematic diagrams showing a method for manufacturing a laminated optical film according to the second embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. In the drawings, the same reference numerals are given to the same components. All of FIGS. 1 to 6 show a plane perpendicular to the rotation axis of the first roll 7a and the rotation axis of the second roll 7b. Both the first roll 7a and the second roll 7b have a substantially cylindrical shape. Each of FIGS. 1 to 6 shows a plane perpendicular to the surface of each film, and the film and the laminate are shown as lines. X, Y, and Z shown in FIGS. 1 to 3 and 5 mean three coordinate axes orthogonal to each other. The Z-axis points in the vertical direction. The X axis and the Y axis are horizontal.

(First embodiment)
The first embodiment relates to a method for manufacturing a polarizing plate, which is a type of laminated optical film. The method for manufacturing a polarizing plate according to the first embodiment includes a coating step, a bonding step, and an irradiation step. In the coating step, a coating film containing an active energy ray-curable resin is formed on the surface of a film-shaped substrate. In the bonding step, the base material is bonded to the surface of the film-shaped polarizer via the coating film. In the irradiation step, the coating film sandwiched between the base material and the polarizer is irradiated with active energy rays. Hereinafter, each step will be described in detail.

As shown in FIG. 1, the manufacturing apparatus 100 for a laminated optical film (polarizing plate) according to the first embodiment is directed between a pair of rolls (first roll 7a and second roll 7b) and a pair of rolls. And an irradiation device 3 for irradiating the active energy ray L. The first roll 7a and the second roll 7b are arranged parallel to each other.

As shown in FIGS. 1 to 4, in the bonding step, the first laminated body 24 and the second laminated body 22b are used. The first stacked body 24 includes a film-shaped polarizer 38, an adhesive layer 36 that overlaps the polarizer 38, and a protective film 34 that is attached to the polarizer 38 via the adhesive layer 36. The second stacked body 22b includes a film-shaped base material 22a and a coating film 32a formed on the surface of the base material 22a.

The film-shaped polarizer 38 included in the first stacked body 24 may be manufactured by the following procedure, for example.

First, a film-shaped polyvinyl alcohol resin is stretched uniaxially or biaxially. 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 cross-linking agent (for example, an aqueous solution of boric acid) for cross-linking. After the treatment with the crosslinking agent, the polyvinyl alcohol resin is washed with water and then dried. The polarizer 38 is obtained through the above procedure. The polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based 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, in addition to ethylene, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, or acrylamides having ammonium groups. The polyvinyl alcohol-based resin may be modified. The modified polyvinyl alcohol-based resin may be, for example, aldehyde-modified polyvinyl formal, polyvinyl acetal, or polyvinyl butyral.

The thickness of the polarizer 38 may be, for example, 30 μm or less, 20 μm or less, 10 μm or less, or 8 μm or less. The thinner the polarizer 38, the easier it is to make the entire polarizing plate thinner. The thickness of the polarizer 38 may be, for example, 2 μm or more. The thicker the polarizer 38, the easier the mechanical strength of the polarizer 38 is improved.

The protective film 34 has a function of protecting the polarizer 38. The protective film 34 only needs to be a translucent thermoplastic resin, and may be an optically transparent thermoplastic resin. The resin forming 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. Alternatively, it may be a copolymer.

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

The cyclic polyolefin-based 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-based resin may be, for example, a copolymer of a cyclic olefin and a chain olefin (for example, a random copolymer). 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-based resin may be, for example, a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer.

The cellulose ester resin may be, for example, cellulose triacetate (triacetyl cellulose), cellulose diacetate, cellulose tripropionate or cellulose dipropionate. You may use these copolymers. A cellulose ester-based resin in which a part of hydroxyl groups is modified with another substituent may be used.

A polyester resin other than the cellulose ester resin may be used. The polyester resin may be, for example, a polycondensate of a polyvalent carboxylic acid or its derivative and a polyhydric alcohol. The polycarboxylic acid or its derivative may be a dicarboxylic acid or its derivative. The polycarboxylic acid or its derivative 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 can 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, polycyclohexane dimethyl terephthalate, or polycyclohexane dimethyl naphthalate. ..

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

The (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 copolymer. Polymer; methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymer; methyl (meth)acrylate-styrene copolymer (for example, MS resin); methyl methacrylate and alicyclic hydrocarbon group It may be a copolymer with a compound (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth)acrylate 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, for example, 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 entire polarizing plate thinner. The thickness of the protective film 34 may be, for example, 5 μm or more. The thicker the protective film 34, the easier the mechanical strength and handleability of the protective film 34 improve.

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 having an arbitrary retardation value is obtained by stretching a film made of the above thermoplastic resin or forming a liquid crystal layer or the like on the film.

The adhesive layer 36 may contain an aqueous adhesive such as polyvinyl alcohol, and may contain 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. The thicker the adhesive layer 36 is, the more difficult bubbles are formed between the polarizer 38 and the protective film 34, and the polarizer 38 and the protective film 34 are more easily adhered to each other. The thinner the adhesive layer 36, the easier it is to make the entire polarizing plate thinner.

As shown in FIG. 1, the first stacked body 24a is conveyed in the direction d24 and supplied between the pair of bonding rolls (first roll 7a and second roll 7b). The guide roll 5a contacts the surface of the protective film 34 included in the first laminate 24.

As shown in (a) of FIGS. 1 and 4, in the coating step, the coating device 1 is used to apply the coating film 32a containing the active energy ray-curable resin to the surface of the film-shaped substrate 22a. Form. As a result, the second stacked body 22b including the base material 22a and the coating film 32a formed on the surface of the base material 22a is obtained. The coating device 1 may be, for example, a gravure coater such as a microchamber doctor. The coating film 32a may include, for example, an active energy ray curable resin.

The active energy ray curable resin is a resin that is cured by being irradiated with an active energy ray. The active energy rays may be, for example, ultraviolet rays, visible light, electron rays, or X-rays. The active energy ray curable resin may be 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, it is not necessary to perform the drying step for removing the solvent after the coating step or the irradiation step. Further, the ultraviolet curable resin is easier to use together with the protective film having a lower moisture permeability than the water-based adhesive.

The active energy ray-curable resin may be one kind of resin and may contain plural kinds of resins. For example, the active energy ray curable resin may include a cationically polymerizable curable compound or a radically polymerizable curable compound. The active energy ray curable resin may contain a cationic polymerization initiator or a radical polymerization initiator for initiating a curing reaction of the curable compound.

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

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

The base material 22a may be a film similar to the protective film 34.

As shown in FIG. 1, the second laminated body 22b is conveyed in the direction d22 and supplied between the pair of bonding rolls (first roll 7a and second roll 7b). The guide roll 5b contacts the surface of the base material 22a included in the second stacked body 22b.

As shown in FIGS. 1 to 4, in the bonding step, the coating film 32a of the second laminated body 22b is opposed to the polarizer 38 of the first laminated body 24, and the first laminated body 24 and the second laminated body 22b are separated. Overlap. The first laminated body 24 and the second laminated body are sandwiched by the first laminated body 24 and the second laminated body 22b, which are overlapped with each other through the coating film 32a (active energy ray curable resin), by a pair of rolls (7a, 7b), and the first laminated body 24 and the second laminated body. The body 22b is attached. In other words, the base material 22a is bonded to the surface of the polarizer 38 via the coating film 32a using the pair of rolls (7a, 7b).

The first roll 7a may be made of, for example, a metal, and the second roll 7b may be made of, for example, an elastic body. The metal forming the first roll 7a (base material of the first roll 7a) may be, for example, iron or stainless steel (SUS304 or the like). The elastic body forming the second roll 7b (base material of the second roll 7b) may be, for example, nitrile rubber (NBR), urethane rubber, silicone rubber, or ethylene propylene diene rubber (EPDM). Both the first roll 7a and the second roll 7b may be made of metal. Both the first roll 7a and the second roll 7b may be made of an elastic body.

The diameter of the cross section (circle) of the first roll 7a perpendicular to the rotation axis may be, for example, 40 to 400 mm, or 80 to 250 mm. The diameter of the cross section (circle) of the second roll 7b perpendicular to the rotation axis may also be, for example, 40 to 400 mm, or 80 to 250 mm. As shown in FIGS. 1 and 2, the diameter of the first roll 7a may be the same as the diameter of the second roll 7b. As shown in FIG. 3, the diameter of the first roll 7a may be different from the diameter of the second roll 7b. The size relationship between the diameter of the first roll 7a and the diameter of the second roll 7b shown in FIG. 3 may be reversed. The width of the first roll 7a in the direction of the rotation axis may be, for example, 300 to 3000 mm. The width of the second roll 7b in the direction of the rotation axis may also be 300 to 3000 mm, for example.

The thickness of the first roll 7a should be substantially uniform, and the thickness of the second roll 7b should also be substantially uniform. When both rolls have a uniform thickness, uniform pressure tends to act on the plurality of films (the first laminate 24 and the second laminate 22b) sandwiched between the rolls. As a result, it is difficult for wrinkles to be formed on the film. The diameter of the first roll 7a may decrease from the central portion of the first roll 7a toward the end portion. That is, the first roll 7a may be a roll (crown roll) having a tapered outer peripheral shape. The second roll 7b may also be a crown roll.

The pressure exerted by the first roll 7a and the second roll 7b on the first stacked body 24 and the second stacked body 22b may be, for example, 0.3 to 3.0 MPa, or 0.7 to 2.3 MPa.

Through the above bonding step, the third laminated body 26a shown in (b) of FIG. 4 is obtained. The third laminate 26a includes a base material 22a, a coating film 32a overlapping the base material 22a, a polarizer 38 overlapping the coating film 32a, an adhesive layer 36 overlapping the polarizer 38, and a protection layer overlapping the adhesive layer 36. And a film 34.

As shown in FIG. 1, in the irradiation step, the third laminated body 26a (the laminated first laminated body 24 and second laminated body 22b) is fed out between the pair of rolls (7a and 7b) in the direction d26. .. Then, the irradiation device 3 is used to irradiate the active energy ray L between the pair of rolls (7a and 7b) from which the third stacked body 26a is fed. In the irradiation step, immediately after bonding the plurality of films (first laminate 24 and second laminate 22b) with a pair of rolls (7a and 7b), between the pair of rolls (7a and 7b), The active energy ray L may be irradiated. In the irradiation step, the plurality of films (the first laminate 24 and the second laminate 22b) are bonded together by the pair of rolls (7a and 7b), and at the same time, the films are directed between the pair of rolls (7a and 7b). Alternatively, the active energy ray L may be irradiated.

In the irradiation step, by irradiation with the active energy ray L, the active energy ray-curable resin in the coating film 32a of the third stacked body 26a cures to become the resin layer 32b (see FIG. 4B). .. The resin layer 32b may be a protective layer that protects the polarizer 38. The resin layer 32b may be an optical compensation layer.

Simultaneously with the laminating step or immediately after the laminating step, the active energy ray curable resin interposed between the plurality of films (the first laminate 24 and the second laminate 22b) is cured to thereby obtain a plurality of films. Are easily fixed to each other via resin. As a result, peeling of the films in the plurality of films (third laminate 26a) after the irradiation step is suppressed. Even if the film is deformed, loosened, or curved during transportation after the irradiation step, peeling between the films is suppressed. In order to suppress the peeling of the film after the irradiation step, the active energy ray-curable resin does not necessarily have to be completely cured in the irradiation step. Incomplete curing, semi-curing or temporary curing of the active energy ray-curable resin in the irradiation step can sufficiently suppress the peeling of the film after the irradiation step. That is, in the irradiation step, the coating film 32a may be incompletely cured or may be completely cured. In other words, the resin layer 32b may be a semi-cured resin layer or a completely cured resin layer. The transport speed of the third laminate 26a (a plurality of films that have been bonded together) is not particularly limited, but may be, for example, 1 to 100 m/min, or 10 to 30 m/min. When the transport speed is within the above-mentioned range, the active energy ray-curable resin interposed between the plurality of films (the first laminate 24 and the base material 22a) at the same time as the bonding step or immediately after the bonding step. Is easy to cure.

As described above, in the first embodiment, the irradiation process is performed at a timing earlier than the conventional one. That is, in the first embodiment, curing of the active energy ray-curable resin is started earlier than in the conventional case. As a result, the plurality of films are fixed to each other via the resin earlier than before, and the peeling of the films is suppressed.

"Between a pair of rolls (7a and 7b) in which a plurality of laminated films (first laminated body 24 and second laminated body 22b) are fed" is paraphrased as "irradiation space IS" described below. .. As shown in FIG. 2 and FIG. 3, the tangent plane Pt intersects with the plurality of films (the first laminate 24 and the second laminate 22b) that are bonded together, and the pair of rolls (7a, 7b). It is defined as the plane that touches both surfaces. That is, the tangent plane Pt contacts the surface of the first roll 7a (side surface of the cylinder) and also contacts the surface of the second roll 7b (side surface of the cylinder). The tangent plane Pt is a virtual plane. The line of intersection I is defined as the line of intersection between the tangent plane Pt and the plurality of laminated films. The intersection line I is a virtual straight line. The rotation axis A1 is defined as the rotation axis of the first roll 7a. The rotation axis A2 is defined as the rotation axis of the second roll 7b. The plane Pa is defined as a plane including both the rotation axes (A1, A2) of the pair of rolls. The plane Pa is a virtual plane. The distance R is defined as the distance between the intersection line I and the plane Pa. Based on the above Pt, I, A1, A2, Pa and R, the “irradiation space IS” is defined as a cylindrical space whose intersection line I is the central axis and whose radius is R. The irradiation space IS is a virtual space. The irradiation step can be restated as a step of irradiating a part or all of the plurality of films located in the irradiation space IS with the active energy ray. The active energy ray may be irradiated to a region (irradiation region IS′) surrounded by the pair of rolls (7a and 7b) and the tangent plane Pt in the irradiation space IS. That is, in the irradiation step, a part or all of the plurality of films located in the irradiation region IS′ may be irradiated with the active energy ray. In the case of irradiating the irradiation area IS′ with active energy rays, the active energy ray curing interposed between the plurality of films (the first laminate 24 and the base material 22a) is performed at the same time as the bonding step or immediately after the bonding step. Resin is easier to cure. A part of the active energy ray L may be applied to the plurality of films (the first laminate 24 and the base material 22a) that have passed through the irradiation space IS. Curing of the active energy ray curable resin (the coating film 32a or the resin layer 32b) is performed by the active energy rays L irradiated on the plurality of films (the first laminate 24 and the base material 22a) after passing through the irradiation space IS. It may be further promoted.

In the irradiation step, it is preferable that the active energy rays L are uniformly irradiated on the whole of the plurality of films (third laminate 26a). Therefore, it is preferable that the light source of the active energy ray L included in the irradiation device 3 extends in the width direction (Y-axis direction) of the plurality of films (the first laminate 24 and the base material 22a) to be bonded. In other words, the light source of the active energy ray L included in the irradiation device 3 should extend along the rotation axis direction (Y axis direction) of the pair of rolls (7a and 7b). The manufacturing apparatus 100 may include a mechanism (irradiation angle adjusting means) that freely adjusts the direction of the active energy ray L emitted from the irradiation device 3. The manufacturing apparatus 100 may have a mechanism (irradiation position adjusting means) that freely moves the irradiation device 3 in the vertical direction (Z-axis direction) or the horizontal direction (X-axis direction or Y-axis direction).

The irradiation device 3 may be, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, or a metal halide lamp. The irradiation intensity of the active energy ray L may be, for example, 30 to 100 mJ/cm ² .

As shown in FIG. 1, in the irradiation step, the coating film 32a may be irradiated with the active energy rays L from the side of the base material 22a. That is, the active energy ray L may be applied to the coating film 32a via the base material 22a. The active energy ray L may be applied to the coating film 32a from the protective film 34 side. That is, the irradiation device 3 may be disposed on the protective film 34 side, and the coating film 32 a may be irradiated with the active energy ray L via the protective film 34 and the polarizer 38. You may irradiate the coating film 32a with the active energy ray L from the base material 22a side and the protective film 34 side. That is, the active energy ray L may be applied to both surfaces (front and back) of the coating film 32a. In the irradiation process using the irradiation device 3, when the coating film 32a is incompletely cured, a second irradiation process using another irradiation device may be performed after the irradiation process using the irradiation device 3. After the second irradiation step, a third irradiation step using another irradiation device may be performed. That is, the coating film 32a may be incompletely cured in the first irradiation step using the irradiation device 3, and the coating film 32a may be completely cured in the second and subsequent irradiation steps using another irradiation device.

The peeling step may be performed after the irradiation step. As shown in FIGS. 1 and 4B and 4C, in the peeling step, the base material 22a is peeled from the resin layer 32b of the third stacked body 26a. In the peeling step, the guide roll 5c contacts the base material 22a included in the third stacked body 26a. The fourth stacked body 26b from which the base material 22a is peeled off is conveyed in the direction d26.

When the peeling process is performed, the completed polarizing plate does not include the base material 22a. In other words, the polarizing plate (fourth stacked body 26b) completed through the peeling step has a resin layer 32b and a polarizer 38 directly overlapping the resin layer 32, as shown in (c) of FIG. The protective film 34 is attached to the polarizer 38 via the adhesive layer 36.

When the peeling step is performed, the coating film 32a may be formed on the surface of the base material 22a that has not been roughened in the coating step. When the roughening treatment is applied to the base material 22a, the coating film 32a easily adheres to the surface of the base material 22a, and the base material 22a is less likely to be peeled off from the cured coating film 32a (resin layer 32b). When the peeling step is performed, the coating film 32a is formed on the surface of the base material 22a that has not been roughened, so that the base material 22a can be easily peeled from the resin layer 32b in the peeling step. The roughening treatment may be, for example, plasma treatment, corona treatment, ultraviolet irradiation treatment, or flame treatment (flame treatment).

The peeling step may not be performed. When the peeling step is not performed, the surface of the base material 22a may be roughened before the coating step. In the subsequent coating step, the coating film 32a may be formed on the surface of the roughened base material 22a. As a result, it becomes difficult for the base material 22a to be separated from the resin layer 32b. When the peeling step is not carried out, the completed polarizing plate has a base material 22a, a resin layer 32b overlapping the base material 22a (a coating film 32a after curing), and a resin layer, as shown in (b) of FIG. A polarizer 38 that overlaps 32 b, an adhesive layer 36 that overlaps the polarizer 38, and a protective film 34 that overlaps the adhesive layer 36 are provided. The base material 22 a may function as a film that protects the polarizer 38. The polarizing plate including the base material 22a may include another optical layer laminated on the base material 22a.

The polarizing plate may include another optical film (optical layer) laminated on the protective film 34, the base material 22a, or the resin layer 32b. The other optical film (optical layer) is, for example, a reflective polarizing film, a film with an antiglare function, a film with a surface antireflection function, a reflective film, a semi-transmissive reflective film, a viewing angle compensation film, a hard coat layer, an adhesive layer. , A touch sensor layer, an antistatic layer or an antifouling layer.

(Second embodiment)
The method for producing a laminated optical film according to the second embodiment of the present invention is the same as that of the first embodiment, except for the matters described below. In the following, description of matters common to the first embodiment and the second embodiment will be omitted.

The manufacturing method of the laminated optical film which concerns on 2nd embodiment is equipped with a coating process, a bonding process, and an irradiation process 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 laminating step of the second embodiment, a film-shaped polarizer is arranged between a pair of base materials. Then, the pair of base materials are attached to both surfaces of the polarizer through the coating film. In the irradiation step of the second embodiment, after the pair of base materials are attached to both surfaces of the polarizer, the coating film is irradiated with active energy rays. These steps will be described in detail below.

As shown in FIG. 5, the laminated optical film (polarizing plate) manufacturing apparatus 200 according to the second embodiment is directed between a pair of rolls (first roll 7a and second roll 7b) and a pair of rolls. , A pair of irradiation devices 3a and 3b for irradiating the active energy ray L. The irradiation devices 3a and 3b may be the same as the irradiation device 3 used in the first embodiment.

As shown in (a) of FIG. 5 and FIG. 6, in the coating process of the second embodiment, the coating device 1a is used to coat the coating film 54a containing the active energy ray-curable resin with a film-shaped base. It is formed on the surface of the material 44a to produce a laminated body 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 step, 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-shaped substrate 42a to produce the laminated body 42b. The laminated body 42b of the second embodiment may be the same as the second laminated body 22b of the first embodiment. The coating film 54a of the laminate 44b may have the same composition as the coating film 52a of the laminate 42b. The coating film 54a of the laminate 44b may have a composition different from that of the coating film 52a of the laminate 42b. The composition of the base material 44a of the laminated body 44b may be the same as that of the base material 42a of the laminated body 42b. The composition of the base material 44a of the laminated body 44b may be different from that of the base material 42a of the laminated body 42b. The coating devices 1a and 1b may be the same as the coating device 1 of the first embodiment.

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

As shown in FIGS. 5 and 6, in the bonding step of the second embodiment, the polarizer 38 is sandwiched between the pair of laminated bodies 42b and 44b. The coating film 54 a of the laminate 44 b faces one surface of the polarizer 38. The coating film 52a of the laminated body 42b faces the other surface of the polarizer 38. Then, the laminated body 44b, the polarizer 38, and the laminated body 42b are stacked and sandwiched by a pair of rolls (7a and 7b). As a result, as shown in FIG. 6B, the base material 44a is bonded to one surface of the polarizer 38 via the coating film 54a. The base material 42a is attached to the other surface of the polarizer 38 via the coating film 52a. 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. A laminated body 46 including is obtained.

As shown in FIG. 5, in the irradiation step, the laminated body 46 (the laminated polarizer 38 and the laminated bodies 42b and 44b) is fed out in a direction d46 from between the pair of rolls (7a and 7b). Then, using the pair of irradiation devices 3a and 3b, the active energy ray L is irradiated toward between the pair of rolls (7a and 7b) from which the laminated body 46 is fed. That is, in the irradiation step, a part or all of the plurality of films (the laminated body 46) located in the irradiation space IS is irradiated with the active energy ray. In the irradiation step, a part or all of the plurality of films (laminated body 46) located in the irradiation region IS′ may be irradiated with the active energy ray. As described below, the definition of the irradiation space IS in the second embodiment is almost the same as the definition of the irradiation space IS in the first embodiment. The definition of the irradiation area IS' in the second embodiment is almost the same as the definition of the irradiation area IS' in the first embodiment. The tangent plane Pt is defined as a plane that intersects the plurality of laminated films (laminated body 46) and is in contact with both surfaces of the pair of rolls (7a, 7b). The line of intersection I is defined as the line of intersection between the tangent plane Pt and the plurality of laminated films (laminated body 46). The rotation axis A1 is defined as the rotation axis of the first roll 7a. The rotation axis A2 is defined as the rotation axis of the second roll 7b. The plane Pa is defined as a plane including both the rotation axes (A1, A2) of the pair of rolls. The distance R is defined as the distance between the intersection line I and the plane Pa. The “irradiation space IS” is defined as a cylindrical space whose intersection line I is the central axis and whose radius is R. The irradiation region IS' is defined as a region of the irradiation space IS surrounded by the pair of rolls (7a and 7b) and the tangent plane Pt. In the irradiation step, immediately after bonding the polarizer 38 and the laminates 42b and 44b with the pair of rolls (7a and 7b), the active energy ray L is irradiated toward between the pair of rolls (7a and 7b). You may In the irradiation step, the polarizer 38 and the laminated bodies 42b and 44b are bonded together with a pair of rolls (7a and 7b), and at the same time, the active energy ray L is irradiated toward between the pair of rolls (7a and 7b). You may.

In the irradiation step, the irradiation device 3a is used to indirectly irradiate the coating film 54a with the active energy rays L from the side of the base material 44a to cure the coating film 54a. At the same time, the irradiation device 3b is used to indirectly irradiate the coating film 52a with the active energy ray L from the side of the base material 42a to cure the coating film 52a. Through the above irradiation process, the resin layer 52b is formed from the coating film 52a and the resin layer 54b is formed from the coating film 54a. The coating film 52a may be incompletely cured or may be completely cured. In other words, the resin layer 52b may be a semi-cured resin layer or a completely cured resin layer. The coating film 54a may be incompletely cured or may be completely cured. In other words, the resin layer 54b may be a semi-cured resin layer or a completely cured resin layer. One of the irradiation devices 3a and 3b may be omitted. That is, both the coating films 52a and 54a may be cured only by the active energy rays L emitted from one of the irradiation devices 3a and 3b.

As described above, also in the second embodiment, the irradiation step is performed at a timing earlier than that of the conventional one. That is, also in the second embodiment, the curing of the active energy ray-curable resin is started earlier than in the conventional case. As a result, the plurality of films are fixed to each other via the resin earlier than before, and the peeling of the films is suppressed.

Also in the second embodiment, a part of the active energy ray L may be applied to the laminated body 46 after passing between the pair of rolls (7a and 7b). That is, a part of the active energy ray L may be applied to the laminated body 46 that has passed through the irradiation space IS.

When the active energy ray curable resin (coating 52a or 54a) is incompletely cured by the irradiation of the active energy ray L directed between the pair of rolls (7a and 7b), another irradiation step (second time). Irradiation step) may be performed. For example, the laminated body 46 is conveyed between the pair of rolls (7a and 7b) along the direction d46. The surface of the laminated body 46 on the base material 42a side is brought into contact with the cooling roll 9. The surface of the laminate 46 facing the side opposite to the cooling roll 9 on the side of the base material 44a is irradiated with the active energy rays L from the irradiation device 3c. The active energy ray L penetrates the base material 44a and reaches the coating films 52a and 54a. The second irradiation of the active energy ray L accelerates the curing of the coating films 52a and 54a. The coatings 52a and 54a may be completely cured by the second irradiation step. The irradiation device 3c may be the same as the irradiation device 3 used in the first embodiment.

In a modification of the second irradiation step, the active energy ray L may be irradiated onto the coating film 32a from the side of the base material 42a of the laminated body 46. That is, the irradiation device 3c may be arranged on the base material 42a side of the laminated body 46, and the active energy rays L may be applied to the coating films 52a and 54a via the base material 42a. In the second irradiation step, a pair of irradiation devices may be used to irradiate the coating films 52a and 54a with the active energy rays L from both surface sides of the laminated body 46.

The coating films 52a and 54a may be incompletely cured by the second irradiation step using the irradiation device 3c. In this case, another irradiation step (third irradiation step) may be performed. For example, the laminated body 46 is conveyed from the irradiation device 3c to the irradiation device 3d via the guide roll 5f. Then, the active energy ray L is again applied to the coating films 52a and 54a using the irradiation device 3d. The irradiation of the active energy ray L for the third time accelerates the curing of the coating films 52a and 54a. The irradiation device 3d may be the same as the irradiation device 3 used in the first embodiment.

In the second embodiment, the peeling step may be performed after the irradiation step. For example, in the peeling step, the base material 42a may be peeled from the resin layer 52b of the laminate 46. The base material 44a may be separated from the resin layer 54b of the laminated body 46.

When the peeling process is performed, the polarizing plate completed in the second embodiment does not include the base material 42a or 44a. For example, the polarizing plate completed through the peeling step 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 film (optical layer) laminated on the resin layer 52b or 54b. The other optical film (optical layer) is, for example, a reflective polarizing film, a film with an antiglare function, a film with a surface antireflection function, a reflective film, a semi-transmissive reflective film, a viewing angle compensation film, a hard coat layer, an adhesive layer. , A touch sensor layer, an antistatic layer or an antifouling layer.

When the peeling process is performed, the base materials 42a and 44a that have not been roughened may be used in the coating process.

In the second embodiment, only one of the base materials 42a or 44a may be peeled off in the peeling step. When only one of the base materials 42a or 44a is to be peeled off, a roughened base material may be used in the coating step as the non-peeling side base material. In the second embodiment, the peeling process may not be performed. When the peeling step is not performed, the base material subjected to the roughening treatment may be used in the coating step. When the peeling step is not performed, the polarizing plate completed in the second embodiment may be the laminated body 46 itself shown in (b) of FIG. The polarizing plate may include another optical film (optical layer) laminated on the base material 42a or 44a. The other optical film (optical layer) is, for example, a reflective polarizing film, a film with an antiglare function, a film with a surface antireflection function, a reflective film, a semi-transmissive reflective film, a viewing angle compensation film, a hard coat layer, an adhesive layer. , A touch sensor layer, an antistatic layer or an antifouling layer.

Although the first and second embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.

For example, the films attached to each other may be an optical film (optical layer) other than the polarizer or a laminated body of these. For example, the film is 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 compensation film, a touch sensor layer, an antistatic layer, an antifouling layer or a liquid crystal layer. And so on.

According to the present invention, for example, in the production of a polarizing plate, it is possible to suppress peeling of the films after the optical films are bonded together.

3a, 3b, 3c, 3d... Irradiation device, 7a... First roll, 7b... Second roll, 22a, 42a, 44a... Base material (film), 24... First laminate (film), 26b... Fourth laminate Body (polarizing plate or laminated optical film), 32a, 52a, 54a... Coating film (active energy ray curable resin), 38... Polarizer (film), 46... Laminated body (polarizing plate or laminated optical film), 100, 200... Manufacturing apparatus for laminated optical film, L... Active energy ray.

Claims (8)

A plurality of films that overlap with each other through the active energy ray curable resin, sandwiched by a pair of rolls,
A laminating step of laminating the plurality of films,
It said plurality of films positioned on your Keru irradiation space IS between the pair of rolls which the plurality of films pasted is paid out, an irradiation step of irradiating the active energy ray directly,
Equipped with
In the irradiation space IS, a center line is an intersection line I between the tangential plane Pt that contacts both surfaces of the rolls forming the pair of rolls and the plurality of films, and the rolls forming the pair of rolls. cylindrical space der that the distance between the radius of the plane Pa containing both axes of rotation and the intersection line I of Ru,
Method for manufacturing laminated optical film. The laminated optical film is a polarizing plate,
The method for producing a laminated optical film according to claim 1. The pair of rolls is made of metal,
The method for manufacturing the laminated optical film according to claim 1. The active energy ray curable resin is an ultraviolet curable resin,
The active energy rays are ultraviolet rays,
The method for manufacturing the laminated optical film according to claim 1. A plurality of films sandwiched via an active energy ray-curable resin, a pair of rolls for laminating the plurality of films,
It said plurality of films in which the plurality of films pasted is located within your Keru irradiation space IS between the pair of rolls fed out, an irradiation device for irradiating an active energy ray directly,
Equipped with
In the irradiation space IS, a center line is an intersection line I between the tangential plane Pt that contacts both surfaces of the rolls forming the pair of rolls and the plurality of films, and the rolls forming the pair of rolls. cylindrical space der that the distance between the radius of the plane Pa containing both axes of rotation and the intersection line I of Ru,
Manufacturing equipment for laminated optical film. The laminated optical film is a polarizing plate,
An apparatus for manufacturing the laminated optical film according to claim 5. The pair of rolls is made of metal,
An apparatus for producing a laminated optical film according to claim 5. The active energy ray curable resin is an ultraviolet curable resin,
The active energy rays are ultraviolet rays,
The manufacturing apparatus of the laminated optical film as described in any one of Claims 5-7.

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