JP6216523B2 - Method for producing multilayer laminated film - Google Patents

Description

  The present invention is a multilayer laminated film in which at least two films having at least one transparent film are pressure-bonded by passing between a laminating roll having a driving roll and a driven roll through an adhesive layer or an adhesive layer. It relates to the manufacturing method.

  The production method of the present invention can be applied to the production of various multilayer laminated films. For example, a first transparent film and a second transparent film can be used as the at least two films. When at least one of the first film and the second transparent film is a transparent conductive film having a transparent conductive layer on one side of the film, it can be used in a method for producing a transparent conductive laminate. The transparent conductive layer in the transparent conductive laminate is used as a transparent electrode in a display system such as a liquid crystal display or an electroluminescence display, a touch panel, or the like, after being appropriately processed. In addition, the transparent conductive laminate, the antistatic of transparent articles, the electromagnetic wave shielding, the liquid crystal light control glass, the transparent heater, etc.

  In the method for producing a multilayer laminated film of the present invention, in addition to the first transparent film and the second transparent film, a third film (and a plurality of films) is passed through an adhesive layer or a pressure-sensitive adhesive layer. And can be laminated. For example, a polarizing film can be used as the third film between the first transparent film and the second transparent film, and used in a method for producing a polarizing plate. In this case, the first and second transparent films are used as a transparent protective film for a polarizing film. Moreover, the manufacturing method of the multilayer laminated film of this invention can be used also in the method of manufacturing the polarizing plate in which a transparent protective film exists only in the one side of a polarizing film. In addition, the method for producing a multilayer laminated film of the present invention can be applied to the production of a multilayer laminated film used for packaging foods, medical devices and the like.

  Conventionally, when a multilayer laminated film is produced by laminating at least two transparent films, an adhesive or a pressure-sensitive adhesive is usually used. In the production of the multilayer laminated film, a pair of laminate rolls of a drive roll and a driven roll is used.

  However, in the method for producing a multilayer laminated film, scratches on the film surface generated during lamination and air bubbles mixed during lamination are factors that greatly reduce production efficiency. As a method for suppressing the generation of scratches at the time of lamination, for example, a method of combining a metal roll and an elastic roll as a laminate roll (Patent Document 1) and a method of adjusting an indentation amount at the time of lamination with a cotter have been proposed. Further, as a method for suppressing air bubble mixing during lamination, a method for suppressing entrained air during lamination by replacement gas purge (Patent Document 2) has been proposed.

JP 2008-037092 A JP 2010-125702 A

  However, in the method for producing a multilayer laminated film, there has been no known method that can suppress both scratches on the film surface that occur during lamination and bubbles that are mixed during lamination.

  The present invention is a method for producing a multilayer laminated film in which at least two films are pressure-bonded by passing between a laminate roll having a driving roll and a driven roll via an adhesive layer or a pressure-sensitive adhesive layer. It is an object of the present invention to provide a production method capable of suppressing both scratches on the film surface that are sometimes generated and air bubbles mixed during lamination.

  As a result of intensive studies to solve the above problems, the present inventors have found that the object can be achieved by the following production method, and have completed the present invention.

That is, in a method for producing a multilayer laminated film in which at least two films are pressure-bonded by passing between a laminate roll having a drive roll and a driven roll via an adhesive layer or a pressure-sensitive adhesive layer.
At least one of the at least two films is a transparent film,
The follower roll is
The driven roll has the first driven roll and the second driven roll,
The diameter of the second driven roll is smaller than the diameter of the driving roll and the first driven roll, and is arranged between the driving roll and the first driven roll,
The present invention relates to a method for producing a multilayer laminated film, wherein the at least two films are pressure-bonded by the driving roll and the second driven roll.

  In the manufacturing method of the said multilayer laminated film, it is preferable that the said drive roll is a metal roll and a said 2nd driven roll is a metal roll or an elastic roll. The elastic roll has a roll core part and an elastic layer provided on the roll core part. The rubber hardness of the elastic layer of the elastic roll relating to the second driven roll is preferably 70 or more and 100 or less.

  In the method for producing the multilayer laminated film, the at least two films may include a first transparent film and a second transparent film. For example, it is suitably applied when at least one of the first transparent film and the second transparent film is a transparent conductive film having a transparent conductive layer on one side of the transparent film.

  A third film can be used between the first transparent film and the second transparent film. For example, it can apply to the method of manufacturing a polarizing plate, using a polarizing film as said 3rd film, and using the transparent protective film for polarizing films as a 1st transparent film and a 2nd transparent film.

  In the manufacturing method of the said multilayer laminated film, it is preferable that the lamination pressure between the said drive roll and the said driven roll is 0.05 Mpa or more and 5 Mpa or less.

  In the method for producing a multilayer laminated film, it is preferable that a difference in rotational speed between the driving roll and the driven roll is 1% or less.

  In the manufacturing method of the said multilayer laminated film, an iron roll or a stainless steel roll is used suitably as said metal roll.

  In a conventional method for producing a multilayer laminated film, for example, a laminate roll combining an elastic roll and a metal roll has been used. For elastic rolls (driven rolls), optimization of rubber hardness has been performed. However, at the time of lamination, due to the difference in the speed of the driving roll (metal roll) and the material of the elastic roll (driven roll), the rotational speed of each roll does not match, so microslip occurs between the film surface and each roll. Scratches were generated on the surface of the multilayer laminated film obtained.

  In the method for producing a multilayer laminated film of the present invention, a driving roll and a driven roll are used for laminating at least two films. As the driven roll, the first driven roll, the driving roll, and the first driven roll A second driven roll having a smaller diameter than the diameter is used. A second driven roll (small diameter roll) is disposed between the driving roll and the first driven roll, and the at least two films are pressure-bonded by the driving roll and the second driven roll (small diameter roll). Thus, in the laminate roll of the present invention, since the film is laminated between the drive roll and the second driven roll (small diameter roll), the difference in rotational speed between the rolls can be kept small, and the film surface Micro-slip with each roll is unlikely to occur, and generation of scratches on the surface of the obtained multilayer laminated film can be suppressed.

  As the laminate roll, a metal roll is preferably used as the driving roll, and a metal roll or an elastic roll is preferably used as the second driven roll (small diameter roll). In particular, when the small-diameter roll is a metal roll or an elastic roll having an elastic layer with high rubber hardness (70 to 100), the outermost surface of the small-diameter roll (second driven roll) has high hardness. In this case, in the combination of the metal roll (driving roll) and the small diameter roll (second driven roll), the outermost surface (metal) of the metal roll (driving roll) and the outermost surface of the small diameter roll (second driven roll) are both. The hardness is high, and the difference in rotational speed between the rolls can be kept small. Therefore, microslip between the film surface and each roll is less likely to occur, and the generation of scratches on the surface of the obtained multilayer laminated film can be further suppressed.

  In addition, it has been found that to suppress air bubbles mixed during lamination, it is effective to increase the amount of pushing from the drive roll and apply a linear pressure of a certain value or more. However, in the laminate roll used in the conventional method for producing a multilayer laminated film, when a linear pressure of a certain value or more is applied, the occurrence of micro slip becomes remarkable and the occurrence of scratches on the film surface increases. On the other hand, if the linear pressure is lowered by adjusting the amount of indentation at the time of lamination in order to suppress the generation of scratches on the film surface, there will be no scratches generated on the film surface, but bubbles will become conspicuous.

  The second driven roll (small-diameter roll) used for the laminate roll of the present invention has good flexibility and elasticity because the first driven roll exists, and the pressing contact surface by the driving roll is elastically deformed (depressed). Thus, the contact area (nip) can be greatly increased. In particular, when the small-diameter roll is a metal roll, or when an elastic roll having an elastic layer with high rubber hardness (70 to 100) is used, the contact area (nip) can be greatly increased. Therefore, according to the laminating roll of the present invention, even when the linear pressure is set low, it is possible to ensure the amount of indentation from the driving roll, and both the scratches on the film surface generated during laminating and the air bubbles mixed during laminating Can be suppressed. When using only the elastic roll whose outermost surface is rubber as the driven roll without using the second driven roll as the driven roll, the outermost surface is deformed and crushed by the linear pressure due to the nip. The length changes, micro slip occurs, and the film surface is scratched. On the other hand, when the first driven roll and the second driven roll (small-diameter roll) are used in combination, the outermost surface is high in hardness, so that the outermost surface is deformed and crushed by linear pressure due to the nip like rubber. There is no change in the length of the entire roll. Therefore, since the driving roll (metal roll) and the small diameter roll (second driven roll) synchronize with each other, micro slip can be suppressed.

It is an example of the schematic of the manufacturing method of the multilayer laminated film of this invention. It is an example of the schematic of the manufacturing method of the multilayer laminated film of this invention. It is an example of the schematic of the manufacturing method of the conventional multilayer laminated film. It is an example of the schematic of the manufacturing method of the conventional multilayer laminated film.

  Below, the manufacturing method of the multilayer laminated film of this invention is demonstrated, referring drawings.

  FIG. 1 shows an example of a method for producing a multilayer laminated film according to the present invention. The first film A1 and the second film A2 are pressed by passing between laminate rolls, and the multilayer laminated film L Is forming. The laminate roll is a combination of a drive roll R1, a first driven roll R2, and a second driven roll R3. The second driven roll (small diameter roll) R3 is disposed between the drive roll R1 and the first driven roll R2. The first film A1 and the second film A2 are pressure-bonded by the driving roll R1 and the second driven roll (small diameter roll) R3.

  FIG. 2 shows an example of a method for producing another multilayer laminated film of the present invention. In FIG. 1, the first film A1 and the second film A2 are provided on both sides of the third film B, and the driving roll. The multilayer laminated film L is formed by pressure bonding by passing between the laminate rolls of R1 and the second driven roll (small diameter roll) R3.

  As the diameter of the driving roll R1, the smaller the diameter, the smaller the area that comes into contact with each film, so the pressure applied to the film surface is relatively higher. For this reason, the diameter of each roll is preferably 300 mm or less, and more preferably 250 mm or less. However, if this diameter is too small, the durability of the roll will be weakened, so that sufficient force cannot be applied. Therefore, it is preferable to use a roll of 50 mm or more, more preferably a roll of 100 mm or more in diameter. Furthermore, it is preferable to use a roll having a diameter of 150 mm or more.

  Moreover, the diameter of the 1st driven roll R2 can use the thing of the range similar to the drive roll R1. The diameter of the first driven roll R2 may be the same as or different from the driving roll R1, but the diameter of the first driven roll R2 is from the viewpoint of further suppressing the deflection of the second driven roll R3. Is preferably approximately the same diameter (± 10 mm) as the diameter of the drive roll R1.

  The diameter of the second driven roll (small diameter roll) R3 is smaller than the diameter of the drive roll R1 and the first driven roll R2. The diameter of the second driven roll (small diameter roll) R3 is preferably 20 mm or more smaller than the diameter (smaller one) of the drive roll R1 and the first driven roll R2, more preferably 50 mm or smaller. On the other hand, if the diameter is too small, the durability of the roll will be weak, and the roll will bend easily and will not be able to be laminated uniformly. For example, as the second driven roll (small diameter roll) R3, It is preferable to use a roll having a diameter of 10 mm or more, and it is more preferable to use a roll having a diameter of 30 mm or more.

  For example, the driving roll R1 and the first driven roll R2 preferably have a diameter of 150 to 250 mm, and in this case, the second driven roll (small diameter roll) R3 preferably has a diameter of 30 to 150 mm. Furthermore, it is preferable that it is 50-100 mm.

  The second driven roll (small diameter roll) R3 is disposed between the driving roll R1 and the first driven roll R2, and the at least two films are formed by the driving roll R1 and the second driven roll (small diameter roll) R3. Is crimped. The arrangement of the second driven roll (small diameter roll) R3 is such that the first film A1 and the second film A2 are pressure-bonded by the driving roll R1 and the second driven roll (small diameter roll) R3, and the multilayer laminated film L is bonded. There is no particular limitation as long as it can be formed. As shown in FIGS. 1 and 2, the second driven roll (small diameter roll) R3 is arranged such that the second driven roll (small diameter roll) R3 has the center point of the second driven roll (small diameter roll) R3 as the driving roll R1. And the first driven roll R2 are preferably provided so as to be on a line connecting the center points of the first driven roll R2 in that the entire roll width can be laminated with a uniform force. In FIGS. 1 and 2, one driven roll R2 and one second driven roll (small-diameter roll) R3 are used as the driven roll, but the first driven roll R2 and the second driven roll ( One or more driven rolls other than (small diameter roll) R3 can be used.

  Various rolls are used for the drive roll R1, the first driven roll R2, and the second driven roll (small diameter roll) R3. For example, a metal roll or an elastic roll can be used.

  Examples of the material for the metal roll include iron, stainless steel, titanium, aluminum, and nickel. As a material of the metal roll, an iron roll or a stainless steel roll is preferable from the viewpoint of cost effectiveness and corrosion resistance.

  The elastic roll has a roll core part and an elastic layer provided on the roll core part. As the material for the roll core, the exemplified metal, resin, or the like is used, and a cylindrical or rod-like material is usually used. The elastic layer is formed of, for example, a rubber material such as silicon rubber or an elastic material such as resin. Moreover, it is preferable that the thickness of an elastic layer is about 0.5-10 mm, for example, Furthermore, it is preferable that it is 1-5 mm.

  The rubber hardness of the elastic layer is preferably selected from the range of 20 to 95. The rubber hardness of the elastic layer can be selected according to the type and thickness of at least two films, an adhesive layer or an adhesive layer. The rubber hardness was measured based on JIS K-6253 (A type).

  In the present invention, at least two films are pressure-bonded by a laminating roll in which a driving roll R1, a driven roll having a first driven roll R2 and a second driven roll (small diameter roll) R3 are combined. At least one of the at least two films is a transparent film. In FIGS. 1 and 2, at least one of the first film A1 and the second film A2 is a transparent film. 1 and 2, the first film A1 is conveyed from the drive roll R1 side, and the second film A2 is conveyed from the driven roll R2 side. At the nip point p between the driving roll R1 and the second driven roll (small-diameter roll) R3 shown in FIGS. 1 and 2, the second driven roll (small-diameter roll) R3 is elastically deformed by pushing from the driving roll R1 side. be able to.

  As the driving roll R1, either a metal roll or an elastic roll can be used, but a multilayer obtained by suppressing the difference in rotational speed from the second driven roll R3 (small diameter roll) to be less likely to cause microslip. It is preferable to use a metal roll from the viewpoint that generation of scratches on the surface of the laminated film can be further suppressed.

  As the first driven roll R2, either a metal roll or an elastic roll can be used, but the difference between the rotational speeds of the driving roll R1 and the second driven roll R3 is suppressed to be small and micro slip is less likely to occur. It is preferable to use a metal roll from the point which can suppress generation | occurrence | production of the crack of the multilayer laminated | multilayer film surface to be produced more.

  As the second driven roll R3 (small-diameter roll), either a metal roll or an elastic roll can be used, but the hardness of the outermost surface is high, and the difference in rotational speed from the drive roll R1 is kept small, resulting in micro slip. It is preferable to use a metal roll or an elastic roll having a rubber hardness of 70 or more and 100 or less from the viewpoint of making it difficult to suppress the generation of scratches on the surface of the resulting multilayer laminated film. The rubber hardness of the elastic layer is preferably 70 or more and 95 or less, and more preferably 80 or more and 95 or less.

In the present invention, the laminate roll is preferably designed in consideration of the combination of the drive roll R1 and the second driven roll R3 (small diameter roll). The combination is
i) Driving roll (metal roll) R1 and second driven roll R2 (elastic roll),
ii) A driving roll (metal roll) R1 and a second driven roll R2 (metal roll) are preferred. In both cases i) and ii), the first driven roll R2 is preferably a metal roll.

  In the case of FIG. 1, between the drive roll R1 and the second driven roll R3 (small-diameter roll), the first film A1 and the second film A2 are adhesive layers or pressure-sensitive adhesive layers (not shown). ) To stick together. In the case of FIG. 2, the first film A1 and the second film A2 are bonded to each other on both surfaces of the third film B via an adhesive layer or an adhesive layer (not shown). The adhesive layer or the pressure-sensitive adhesive layer may be provided on the first film A1 or the second film A2, or may be provided on both sides. When the third film B is used, an adhesive layer or a pressure-sensitive adhesive layer can be provided on one side or both sides of the third film B. The adhesive layer or pressure-sensitive adhesive layer is passed between the drive roll R1 and the second driven roll R3 (small diameter roll) together with the adhesive (solution) or pressure-sensitive adhesive (solution) whose concentration and viscosity are adjusted. It can also be crimped. In addition, the adhesive layer and the pressure-sensitive adhesive layer can be bonded in a solid state.

  The roll diameters of the driving roll R1 and the driven roll (first driven roll R2, second driven roll R3 (small diameter roll) R2), the conveyance speed of the film when bonded, and the like are appropriately adjusted, and the adhesive layer or The thickness of the pressure-sensitive adhesive layer can be adjusted as appropriate.

  Moreover, the conveyance speed at the time of bonding is not particularly limited, and it is usually preferably adjusted at about 2 m / min to 50 m / min.

  The laminating pressure between the laminating rolls (between the driving roll R1 and the second driven roll R3 (small diameter roll) R2) at the time of bonding is not particularly limited and is appropriately set. The laminating pressure is preferably about 0.05 MPa to 5 MPa, more preferably 0.1 MPa to 4 MPa, and more preferably 0 from the viewpoint of suppressing scratches on the film surface and air bubbles mixed during laminating and productivity. .5 MPa or more and 3 MPa or less is preferable. If the laminating pressure is less than 0.05 MPa, sufficient pressing cannot be performed, and bubbles are generated between the films. On the other hand, if the laminating pressure is greater than 5 MPa, scratches on the film surface are likely to occur. Lamination pressure was measured using a pressure-sensitive paper “Prescale” manufactured by Fujifilm, and the color change of the pressure-sensitive paper was binarized by computer image processing. It is obtained from the approximate expression.

<Film>
In the present invention, at least two films are used. Although the thickness in particular of a film is not restrict | limited, For example, it is 1-300 micrometers, it is preferable that it is 10-200 micrometers, and it is more preferable that it is 20-150 micrometers. Various plastic films can be usually used as the film.

<Transparent film>
In the present invention, at least two films are used, but at least one film is a transparent film. The transparent film is not particularly limited, but various plastic films having transparency are used. Examples of the plastic film material include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycycloolefin, polyacetate, polyethersulfone, polycarbonate, polyamide, polyimide, (meth) acrylic polymer, polyvinyl chloride, and polychlorinated chloride. Examples include vinylidene, polystyrene, polyvinyl alcohol, polyarylate, polyphenylene sulfide, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polyolefins such as polyethylene, polypropylene, and ethylene / propylene copolymers. It is done.

  Although the thickness in particular of the said transparent film is not restrict | limited, For example, it is 15-300 micrometers, it is preferable that it is 15-200 micrometers, and it is more preferable that it is 20-150 micrometers. Further, when at least two films have the first transparent film and the second transparent film, the thicknesses of the first transparent film and the second transparent film may be the same or different. For example, when it is set as a thin film, the thickness of one film can be installed in the range of 15 to 75 μm, further 20 to 75 μm, and further 23 to 50 μm.

  The transparent film can be preliminarily subjected to etching treatment or undercoating treatment such as sputtering, corona discharge, plasma discharge, flame, ultraviolet ray irradiation, electron beam irradiation, chemical conversion and oxidation. Moreover, you may remove and clean by solvent washing | cleaning, ultrasonic cleaning, etc. as needed. The transparent film can be provided with an easy-adhesive layer on the bonding surface of the adhesive layer or the pressure-sensitive adhesive layer.

<Transparent conductive film>
The production method of the present invention can be applied to the production of various multilayer laminated films. For example, when the first transparent film and the second transparent film are used as at least two films, the first transparent film and the A transparent conductive laminate can be produced using a transparent conductive film having a transparent conductive layer on one side of the transparent film as at least one of the second transparent films. The transparent conductive film is arranged so that the transparent conductive layer side is the roll side. Moreover, when using a transparent conductive film as either one of a 1st transparent film or a 2nd transparent film, from a viewpoint which does not produce a micro slip effectively, it is transparent conductive on the metal roll (drive roll) side. It is preferable to apply a film.

<Transparent conductive layer>
The constituent material of the transparent conductive layer is not particularly limited, and is selected from the group consisting of indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten. A metal oxide of at least one metal is used. The metal oxide may further contain a metal atom shown in the above group, if necessary. For example, indium tin oxide (ITO), indium zinc oxide, indium oxide-zinc oxide composite oxide, or the like is preferably used, and ITO is particularly preferably used. Further, as the constituent material of the first transparent conductive layer, aluminum zinc oxide, gallium zinc oxide, fluorine zinc oxide, fluorine indium oxide, antimony tin oxide, fluorine tin oxide, phosphorus tin oxide, etc. Can be used. In addition, as a constituent material of the first transparent conductive layer, a conductive polymer such as polythiophene, carbon nanotube, or the like can be used.

The thickness of the transparent conductive layer is not particularly limited, but is preferably 10 nm or more in order to obtain a continuous film having a good conductivity of 1 × 10 ³ Ω / □ or less. The thickness is more preferably 10 to 300 nm, and further preferably 15 to 100 nm. When the film thickness becomes too thick, the transparency is lowered, and it is preferably 15 to 35 nm, more preferably in the range of 20 to 30 nm.

  It does not specifically limit as a formation method of a transparent conductive layer, A conventionally well-known method is employable. Specifically, for example, a method for forming a transparent conductive layer by a vacuum deposition method, a sputtering method, an ion plating method, a coating method or the like can be exemplified. In addition, an appropriate method can be adopted depending on the required film thickness.

<Undercoat layer>
The transparent conductive film can be provided with a transparent conductive layer on the first and second transparent films via an undercoat layer. One or more undercoat layers can be provided. The undercoat layer can be formed of an inorganic material, an organic material, or a mixture of an inorganic material and an organic material.

  The thickness of the undercoat layer is not particularly limited, but is usually about 1 to 300 nm, preferably 5 to 300 nm, from the viewpoint of optical design and the effect of preventing oligomer generation from the first transparent film. It is. In addition, when providing two or more undercoat layers, the thickness of each layer is about 5-250 nm, Preferably it is 10-250 nm.

<Polarizing plate>
Moreover, the manufacturing method of the multilayer laminated film of the present invention uses, for example, a polarizing film as the third film when the first transparent film and the second transparent film are used as at least two films. It can use in the method of manufacturing a polarizing plate, using the transparent protective film for polarizing films as a 2nd transparent film. On the other hand, a transparent film (transparent protective film) and a polarizing film are used as at least two films, and the polarizing plate having a transparent protective film only on one side of the polarizing film can also be used.

  The polarizing film is not particularly limited, and various types can be used. Examples of polarizing films include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films, and two colors such as iodine and dichroic dyes. Examples include polyene-based oriented films such as those obtained by adsorbing a functional material and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizing film made of a polyvinyl alcohol film and a dichroic substance such as iodine is preferable. The thickness of these polarizing films is not particularly limited, but is generally about 5 to 80 μm. The thickness of the polarizing film is preferably 15 to 35 μm. If the thickness of the polarizing film is too thin, it will be easily damaged when bonded to the transparent protective film. On the other hand, if the polarizing film is too thick, the drying efficiency tends to deteriorate, which is not preferable in terms of productivity.

  A polarizing film obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared, for example, by immersing polyvinyl alcohol in an iodine aqueous solution and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution of boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  Moreover, as a polarizing film, for example, a dichroic substance may be kneaded into a polymer film such as a dry stretching method or polyethylene terephthalate (PET), formed into a film, and stretched, or a liquid crystal aligned in a uniaxial direction. O-type that uses dichroic dye as a guest (US Pat. No. 5,523,863, JP-T-3-503322), dichroic lyotropic liquid crystal, etc. E type (US Pat. No. 6,049,428).

  The polarizing film can be used as an optical film obtained by further laminating at least one various optical functional layers. Examples of the optical functional layer include a hard coat treatment layer, an antireflection treatment layer, a sticking prevention treatment layer, a surface treatment layer such as a diffusion layer or an antiglare treatment layer, and an alignment liquid crystal for the purpose of viewing angle compensation or optical compensation. Layer.

<Adhesive layer or pressure-sensitive adhesive layer>
The adhesive layer or the pressure-sensitive adhesive layer is not particularly limited as long as it is optically transparent, and water-based, solvent-based, hot-melt, and radical-curing types are used. As described above, when producing a transparent conductive laminate or a polarizing plate as a multilayer laminate film, a transparent curable adhesive layer is suitable.

<Transparent curable adhesive layer>
For forming the transparent curable adhesive layer, for example, a radical curable adhesive is suitably used. Examples of the radical curable adhesive include active energy ray curable adhesives such as an electron beam curable type and an ultraviolet curable type. In particular, an active energy ray curable adhesive that can be cured in a short time is preferable, and an ultraviolet curable adhesive that can be cured with low energy is more preferable.

  The ultraviolet curable adhesive can be roughly classified into a radical polymerization curable adhesive and a cationic polymerization adhesive. In addition, the radical polymerization curable adhesive can be used as a thermosetting adhesive.

  Examples of the curable component of the radical polymerization curable adhesive include a compound having a (meth) acryloyl group and a compound having a vinyl group. These curable components may be monofunctional or bifunctional or higher. Moreover, these curable components can be used individually by 1 type or in combination of 2 or more types. As these curable components, for example, compounds having a (meth) acryloyl group are suitable.

  Specific examples of the compound having a (meth) acryloyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and 2-methyl-2-nitro. Propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) Acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate 4-methyl-2- Ropirupenchiru (meth) acrylate, n- octadecyl (meth) (meth) acrylic acid (1-20 carbon atoms) such as acrylates alkyl esters.

  Examples of the compound having a (meth) acryloyl group include cycloalkyl (meth) acrylate (for example, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylate (for example, benzyl (meth)). Acrylates), polycyclic (meth) acrylates (for example, 2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl 2-norbornylmethyl (meth) acrylate, etc.), hydroxyl group-containing (meth) acrylic acid esters (eg, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl) Butyl (meth) methacrylate), alkoxy group or phenoxy group-containing (meth) acrylic acid esters (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate), 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, etc.), epoxy group-containing (meth) acrylic acid esters (for example, glycidyl (meth) acrylate, etc.), halogen-containing ( (Meth) acrylic acid esters (for example, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropro) Le (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate), alkylaminoalkyl (meth) acrylates (e.g., dimethylaminoethyl (meth) acrylate, etc.) and the like.

  Moreover, as a compound which has (meth) acryloyl group other than the above, hydroxyethyl acrylamide, N-methylol acrylamide, N-methoxymethyl acrylamide (SP value 22.9), N-ethoxymethyl acrylamide, (meth) acrylamide, etc. Examples thereof include amide group-containing monomers. Moreover, nitrogen-containing monomers, such as acryloyl morpholine, etc. are mentioned.

  Examples of the curable component of the radical polymerization curable adhesive include compounds having a plurality of polymerizable double bonds such as a (meth) acryloyl group and a vinyl group, and the compound can be used as a crosslinking component. It can also be mixed with the adhesive component. Examples of the curable component that becomes such a crosslinking component include tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, and EO. Modified diglycerin tetraacrylate, Aronix M-220 (manufactured by Toagosei Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DCP-A (kyoeisha) Chemicals), SR-531 (Sartomer), CD-536 (Sartomer) and the like. Moreover, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate monomers, and the like are included as necessary.

  The radical polymerization curable adhesive contains the curable component, and in addition to the component, a radical polymerization initiator is added according to the type of curing. When the adhesive is used as an electron beam curable type, it is not particularly necessary that the adhesive contains a radical polymerization initiator, but when it is used as an ultraviolet curable type or a thermosetting type, radical polymerization is started. An agent is used. The usage-amount of a radical polymerization initiator is about 0.1-10 weight part normally per 100 weight part of sclerosing | hardenable components, Preferably, it is 0.5-3 weight part. Moreover, the radical polymerization curable adhesive may be added with a photosensitizer that increases the curing speed and sensitivity of the electron beam typified by a carbonyl compound, if necessary. The usage-amount of a photosensitizer is about 0.001-10 weight part normally per 100 weight part of sclerosing | hardenable components, Preferably, it is 0.01-3 weight part.

  Examples of the curable component of the cationic polymerization curable adhesive include compounds having an epoxy group or an oxetanyl group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various generally known curable epoxy compounds can be used. As a preferable epoxy compound, a compound having at least two epoxy groups and at least one aromatic ring in the molecule, or at least two epoxy groups in the molecule, at least one of which has an alicyclic ring. Examples thereof include a compound formed between two adjacent carbon atoms constituting it.

  For forming the transparent curable adhesive layer, examples of the water-based curable adhesive include vinyl polymer, gelatin, vinyl latex, polyurethane, isocyanate, polyester, and epoxy. . Such an adhesive layer composed of an aqueous adhesive can be formed as an aqueous solution coating / drying layer, etc., but when preparing the aqueous solution, a catalyst such as a crosslinking agent, other additives, and an acid can be used as necessary. Can be blended.

  As the water-based adhesive, an adhesive containing a vinyl polymer is preferably used, and the vinyl polymer is preferably a polyvinyl alcohol resin. Moreover, as a polyvinyl alcohol-type resin, the adhesive agent containing the polyvinyl alcohol-type resin which has an acetoacetyl group is more preferable from the point which improves durability. Moreover, as a crosslinking agent which can be mix | blended with a polyvinyl alcohol-type resin, the compound which has at least two functional groups reactive with a polyvinyl alcohol-type resin can be used preferably. For example, boric acid, borax, carboxylic acid compounds, alkyldiamines; isocyanates; epoxies; monoaldehydes; dialdehydes; amino-formaldehyde resins; and divalent or trivalent metal salts and oxides thereof Is mentioned.

  The adhesive that forms the curable adhesive layer may appropriately contain an additive if necessary. Examples of additives include coupling agents such as silane coupling agents and titanium coupling agents, adhesion promoters typified by ethylene oxide, additives that improve wettability with transparent films, acryloxy group compounds and hydrocarbons (Natural and synthetic resins) and other additives that improve mechanical strength and processability, UV absorbers, anti-aging agents, dyes, processing aids, ion trapping agents, antioxidants, tackifiers, Stabilizers such as fillers (other than metal compound fillers), plasticizers, leveling agents, foaming inhibitors, antistatic cracks, heat stabilizers, hydrolysis stabilizers, and the like.

  The adhesive coating method is appropriately selected depending on the viscosity of the adhesive and the target thickness. Examples of coating methods include reverse coaters, gravure coaters (direct, reverse and offset), bar reverse coaters, roll coaters, die coaters, bar coaters, rod coaters and the like. In addition, for coating, a method such as a dapping method can be appropriately used.

  Moreover, it is preferable that the thickness of the said transparent curable adhesive layer is 0.01-10 micrometers. More preferably, it is 0.1-5 micrometers, More preferably, it is 0.3-4 micrometers.

  The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive. Various pressure-sensitive adhesives can be used as the pressure-sensitive adhesive, such as rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives, polyvinylpyrrolidone-based pressure-sensitive adhesives, Examples include acrylamide-based adhesives and cellulose-based adhesives. An adhesive base polymer is selected according to the type of the adhesive. Among the pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and are excellent in weather resistance and heat resistance. The

  As described above, after laminating and bonding the first transparent film and the second transparent film through the adhesive layer or the pressure-sensitive adhesive layer with the laminate roll, a curing treatment and a drying step are appropriately performed. Is done.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded. In each example, both parts and% are based on weight.

Example 1
<Transparent conductive film: first transparent film>
An indium tin oxide (ITO) layer was formed on one side of the polyene terephthalate film using a sputtering apparatus equipped with a sintered body target of indium tin oxide of 97% indium oxide and 3% tin oxide. The thickness of the polyethylene terephthalate film was 25 μm, and the thickness of the indium tin oxide layer was 22 nm.

<Preparation of active energy ray-curable adhesive>
30 parts of hydroxyethyl acrylamide, 30 parts of methyl acrylate, 40 parts of Aronix M-220 (manufactured by Toagosei Co., Ltd.), 1.5 parts of IRGACURE907 (manufactured by Ciba Japan) are mixed and stirred at 50 ° C. for 1 hour for active energy rays A curable adhesive was obtained.

<Manufacture of transparent conductive laminate>
Next, the active energy ray-curable adhesive composition is applied to the surface of the transparent conductive film on which the ITO layer is not formed with an MCD coater (manufactured by Fuji Machine) (cell shape: honeycomb, number of gravure roll wires: 1000). Using this / inch, rotational speed 140% / line speed), the coating was applied to a thickness of 1 μm. Next, a polyethylene terephthalate film (second transparent film) having a thickness of 100 μm was bonded through the active energy ray-curable adhesive. Thereafter, from the second transparent film side, ultraviolet rays (wavelength 365 nm) of a high-pressure mercury lamp are irradiated to cure the adhesive, and a transparent conductive laminate having a transparent conductive layer on one side of the first transparent film is obtained. Obtained. The film thickness was measured using a film thickness meter (Digital Dial Gauge DG-205 manufactured by Peacock). The cumulative amount of ultraviolet light was 600 mJ / cm ² .

<Laminate roll>
For the above bonding, a laminate roll in which the following drive roll and driven roll were combined was used.
Drive roll: SUS roll with a diameter of 200 mm.
First driven roll: a roll made of SUS having a diameter of 200 mm.
Second driven roll: a rubber roll 1 having an elastic layer (thickness of 3 mm, Titan rubber having a rubber hardness of 90) having a diameter of 80 mm (manufactured by Kauki Roll Mfg. Co., Ltd.)
In the embodiment shown in FIG. 1, the first transparent film (transparent conductive film) was conveyed from the drive roll side, and the second transparent film was conveyed from the driven roll side. In each case, the line speed was 15 m / min, and the laminating pressure was 3.0 MPa.

Examples 2-6
A transparent conductive laminate was produced in the same manner as in Example 1 except that the type of the second driven roll, the laminating pressure, and the line speed were changed as shown in Table 1 in <Laminate roll> of Example 1. . In Examples 4 to 6, a rubber roll 2 (manufactured by Kakkuri Roll Co., Ltd.) having an elastic layer (silicon rubber having a thickness of 3 mm and a rubber hardness of 60) having a diameter of 80 mm was used as the second driven roll.

Comparative Examples 1-3
Example 1 <Laminating roll> In the embodiment shown in FIG. 3 (without using the second driven roll), except that the first driven roll, laminating pressure, and line speed were changed as shown in Table 1. A transparent conductive laminate was produced in the same manner as in Example 1. As the first driven roll, a rubber roll 3 having a diameter of 200 mm having an elastic layer (silicon rubber having a thickness of 3 mm and a rubber hardness of 80) was used.

Example 7
<Polarizer: Third film>
A polyvinyl alcohol film having an average polymerization degree of 2400, a saponification degree of 99.9 mol%, and a thickness of 75 μm was immersed in warm water at 30 ° C. for 60 seconds to swell. Subsequently, the film was stretched to 3.5 times while dyeing in an iodine solution of 0.3 wt% (weight ratio: iodine / potassium iodide = 0.5 / 8) at 30 ° C. for 1 minute. Thereafter, the total draw ratio was stretched to 6 times while being immersed in a 4% by weight boric acid aqueous solution at 65 ° C. for 0.5 minutes. After stretching, drying was performed in an oven at 70 ° C. for 3 minutes to obtain a polarizer having a thickness of 26 μm. The moisture content of the polarizer was 13.5% by weight.

<Transparent protective film: 1st and 2nd transparent film>
A lactonized polymethyl methacrylate film (lactonization rate 20%, thickness 30 μm) was used.

<Creation of polarizing plate>
On the two transparent protective films, the same active energy ray-curable adhesive composition as in Example 1 was used, using a micro gravure coater (gravure roll: # 700, rotational speed 175% / line speed), A transparent protective film with an adhesive coated to a thickness of 1 μm was obtained. Next, in the embodiment shown in FIG. 2, the transparent protective film with an adhesive was pasted from both sides of the polarizer using the same laminate roll as in Example 1 under the same conditions. From the bonded transparent protective film side (both sides), ultraviolet rays (gallium filled metal halide lamp, irradiation device: Fusion UV Systems, Inc. Light HAMMER10 manufactured by Inc. Valve: V bulb Peak illuminance: 1600 mW / cm ² , integrated irradiation amount 800 / mJ / The adhesive was cured by irradiating cm ² (wavelength 380 to 440 nm) to obtain a polarizing plate having a transparent protective film on both sides of the polarizer, the line speed was 15 m / min, and the cumulative amount of ultraviolet light 800 mJ / cm. ^{It was set as 2. In} addition, the illumination intensity of the ultraviolet-ray was measured using the Sola-Check system by Solatell.

Examples 8-12
A polarizing plate was produced in the same manner as in Example 7 except that the type of driving roll, laminating pressure, and line speed were changed as shown in Table 2 in <Laminating roll> in Example 7. In Examples 10 to 12, a rubber roll 2 having an elastic layer (silicon rubber having a thickness of 3 mm and a rubber hardness of 60) having a diameter of 80 mm (manufactured by Kakkuri Roll Mfg. Co., Ltd.) was used as the second driven roll.

Comparative Examples 4-6
In <laminate roll> of Example 7, in the mode shown in FIG. 4 (without using the second driven roll), the first driven roll, the lamination pressure, and the line speed were changed as shown in Table 2. A polarizing plate was produced in the same manner as in Example 7. As the first driven roll, a rubber roll 3 having a diameter of 200 mm having an elastic layer (silicon rubber having a thickness of 3 mm and a rubber hardness of 80) was used.

  The following evaluation was performed about the said transparent conductive laminated body. The results are shown in Table 1. Moreover, the following evaluation was performed about the polarizing plate. The results are shown in Table 2.

<Difference in rotational speed between driving roll and second driven roll>
The difference (%) in the rotational speed between the driving roll and the second driven roll was calculated from the measured value of the rotary encoder incremental type E6A2-C manufactured by OMRON Corporation. The difference in rotational speed is preferably 1% or less, more preferably 0.5% or less, and further preferably 0.3% or less.

<Scratches>
The obtained transparent conductive laminate or polarizing plate was irradiated with LED light in a dark room, and scratches observed by transmission and reflection were visually evaluated according to the following criteria.
○: No scratch Δ: No more than 5 scratches in 1 m ^{2 with} a maximum length of less than 1 mm.
X: Scratches with a maximum length of 1 mm or more exceed 5 in 1 m ² .

<Bubble>
Bubbles observed with the microscope (10 times) of the obtained transparent conductive laminate or polarizing plate were evaluated according to the following criteria.
○: No bubbles.
Δ: 5 or less bubbles having a maximum length of less than 30 μm in 25 cm ² .
X: The number of bubbles having a maximum length of less than 30 μm exceeds 5 in 25 cm ² .

  In the embodiment, since a laminate roll in which a drive roll and a second driven roll (small diameter roll) are combined is used, the difference in rotational speed between the drive roll and the second driven roll can be controlled to be small. Even if the pressure is relatively small, scratches and bubbles can be suppressed to produce a transparent conductive laminate and a polarizing plate. On the other hand, in Comparative Examples 1 to 3 and Comparative Examples 4 to 6, since a pair of laminate rolls combining a conventional drive roll (metal roll) and a driven roll (rubber roll which is an elastic roll) is used, The difference in the rotational speed of the driven roll cannot be controlled small. Therefore, in Comparative Examples 1 to 3 and Comparative Examples 4 to 6, there is a scratch even if the laminate pressure is relatively small. Further, in Comparative Examples 2, 3 and Comparative Examples 5 and 6, since the line speed is higher than that in Comparative Examples 1 and 4, the difference in rotational speed also increases, and bubbles tend to deteriorate.

A1 1st film A2 2nd film B 3rd film R1 Drive roll R2 1st driven roll R3 2nd driven roll

Claims (10)

In the method for producing a multilayer laminated film in which at least two films are pressure-bonded by passing between a laminate roll having a drive roll and a driven roll via an adhesive layer or a pressure-sensitive adhesive layer.
At least one of the at least two films is a transparent film,
The driven roll has the first driven roll and the second driven roll,
The diameter of the second driven roll is smaller than the diameter of the driving roll and the first driven roll, and the second driven roll is disposed between the driving roll and the first driven roll,
The difference between the diameter of the first driven roll and the diameter of the drive roll is ± 10 mm or less,
A method for producing a multilayer laminated film, wherein the pressure-bonding of the at least two films is performed by the driving roll and the second driven roll. The drive roll is a metal roll;
The multilayer laminate according to claim 1, wherein the second driven roll is a metal roll or an elastic roll, and the elastic roll has a roll core part and an elastic layer provided on the roll core part. A method for producing a film.   The method for producing a multilayer laminated film according to claim 2, wherein the rubber hardness of the elastic layer of the elastic roll according to the second driven roll is 70 or more and 100 or less.   The said at least 2 film has a 1st transparent film and a 2nd transparent film, The manufacturing method of the multilayer laminated film in any one of Claims 1-3 characterized by the above-mentioned. At least either one of the first transparent film and the second transparent film, Ri transparent conductive film der having a transparent conductive layer on one surface of a transparent film,
The method for producing a multilayer laminated film according to claim 4, wherein a surface resistance of the transparent conductive film is 1 × 10 ³ Ω or less .   The method for producing a multilayer laminated film according to claim 4, wherein a third film is used between the first transparent film and the second transparent film.   The multilayer laminate according to claim 6, wherein the third film is a polarizing film, the first transparent film and the second transparent film are transparent protective films for the polarizing film, and a polarizing plate is produced. A method for producing a film.   The method for producing a multilayer laminated film according to any one of claims 1 to 7, wherein a laminating pressure between the driving roll and the driven roll is 0.05 MPa or more and 5 MPa or less.   The method for producing a multilayer laminated film according to any one of claims 1 to 8, wherein a difference in rotational speed between the driving roll and the driven roll is 1% or less. The said metal roll is an iron roll or a stainless steel roll, The manufacturing method of the multilayer laminated film in any one of Claims 2-9 characterized by the above-mentioned.

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