TWI704057B - Method for producing laminated optical film - Google Patents

Abstract

This invention provide a method for manufacturing a laminated optical film capable of suppressing defects caused by scratches or deformation of laminating roll in a laminated optical film.

This method for manufacturing a laminated optical film of this invention includes introducing a first optical film 2 and a second optical film 3 to be provided on one side or both sides of the first optical film 2 via an adhesive layer or a pressure-sensitive adhesive layer between a pair of rotating laminating rollers 1, 1, and laminating the first optical film 2 and the second optical film 3, wherein, the outermost layer of at least one roller 1 of the pair of lamination rollers 1, 1 is rubber, and the elastic recovery rate of the rubber is 70% or more, so that scratches is not easy to occur on the laminating roller 1, and deformation of the laminating roller 1 is easy to recover.

Description

Manufacturing method of laminated optical film

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

In the past, a polarizing plate has been known as one of the optical components constituting the liquid crystal display device. The polarizing plate is generally a protective film laminated on one side or both sides of the polarizing film to reinforce the mechanical strength, thermal stability, and water resistance of the polarizing film.

Regarding the stacking method of the polarizing film and the protective film, a method of bonding by a pair of bonding rolls is known. For example, in Patent Document 1, two films are bonded to a rubber roller with one of the roller surfaces being rubber.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5399890

Generally, when using a laminating roller to bond optical films to each other, if there are scratches or deformations on the bonding roller, these shapes will be transferred to the optical film, and a defective laminated optical film will be produced.

Therefore, the object of the present invention is to provide a method for manufacturing a laminated optical film that can suppress defects caused by scratches or deformation of the laminating roller in the laminated optical film.

The manufacturing method of the laminated optical film of the present invention involves introducing the first optical film between a pair of laminating rolls that rotate, and the adhesive layer or adhesive is interposed on one side or both sides of the first optical film (pressure sensitive adhesive) layer of the second optical film, bonding the first optical film and the second optical film, wherein, among a pair of bonding rollers, the outermost layer of at least one of the bonding rollers is rubber. The elastic recovery rate is over 70%.

In the manufacturing method of this laminated optical film, the outermost layer of at least one of the laminating rollers of a pair of laminating rollers is rubber, and the elastic recovery rate of rubber is more than 70%, so it is not easy to cause scratches on the laminating roller , The deformation of the laminating roller is easy to recover. Therefore, with this manufacturing method of the laminated optical film, it is possible to suppress the occurrence of defects in the laminated optical film due to scratches or deformation of the laminating roller.

Here, at least one of the second optical films may be a transparent film.

Furthermore, the transparent film may be a protective film, and the first optical film may be a polarizing film. Furthermore, the polarizing film may contain polyvinyl alcohol resin.

In the manufacturing method of the laminated optical film, the thickness of the polarizing film can be 20 μm or less, the thickness of the protective film can be 30 μm or less, and the thickness of the laminated optical film can be 100 μm or less. Generally, the smaller the thickness of the laminated optical film, the more likely it is that defects caused by scratches or deformation of the laminating roll will occur, so each film with this thickness can be said to be suitable for applying the present invention.

Regarding another aspect of the manufacturing method of this laminated optical film, the first optical film system is provided with a polarizing plate of a polarizing film and a protective film, and the first optical film and the second optical film can be bonded via an adhesive layer.

Even in this aspect, the thickness of the polarizing film may be 20 μm or less, the thickness of the protective film may be 30 μm or less, and the thickness of the polarizing plate may be 100 μm or less.

Even in any of the above manufacturing methods, the rubber hardness of the rubber measured in accordance with JIS K 6253 can be 83 to 97°. Even for this rubber hardness, if the elastic recovery rate satisfies the above-mentioned value, the effect of the present invention can be exerted.

Even in any of the above-mentioned manufacturing methods, either of the pair of laminating rollers may be the outermost layer of rubber, and the elastic recovery rate of rubber may be 70% or more. In this case, the effect of the present invention can be further exerted.

Even in any of the above-mentioned manufacturing methods, at least one pressing roller can be brought into contact with at least one of a pair of laminating rollers, and the laminating roller is pressed in a direction in which the pair of laminating rollers approach each other. Pressure. At this time, it becomes easy to apply uniform weight to the width direction of the bonding roll, which is preferable.

According to the present invention, it is possible to provide a method for manufacturing a laminated optical film that can suppress defects caused by scratches or deformation of the laminating roller in the laminated optical film.

1‧‧‧Laminating roller

2‧‧‧Polarizing film (first optical film)

3‧‧‧Protection Film (Second Optical Film)

4‧‧‧Laminated film

5‧‧‧Adhesive layer

6‧‧‧Press roller

7‧‧‧Adhesive layer

8‧‧‧Temporary Protective Film (Second Optical Film)

9‧‧‧Separation film (Second optical film)

10‧‧‧Polarizer (Laminated optical film, the first optical film)

20A, 20B‧‧‧Polarizer with adhesive (multilayer optical film)

Fig. 1 is a diagram showing the state of bonding each film by a pair of bonding rolls.

Figure 2 is a cross-sectional view of the polarizing plate of the first embodiment.

Figure 3 is an explanatory diagram of how to obtain the elastic recovery rate.

Fig. 4(a) is a cross-sectional view of the polarizing plate with adhesive in the second embodiment. Fig. 4(b) is a cross-sectional view of another polarizing plate with adhesive in the second embodiment.

Hereinafter, suitable embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same part or the corresponding part is given the same code|symbol, and the repeated description is abbreviate|omitted. In addition, the size ratio of each drawing may not be consistent with the actual one, and the thickness is particularly exaggerated.

<First Embodiment>

In the first embodiment, an example in which a polarizing film as a first optical film and a protective film as a second optical film are bonded together to manufacture a polarizing plate as a laminated optical film is shown.

As shown in Figure 1, the polarizing film 2 and the protective films 3, 3 arranged on both sides of the polarizing film 2 are transported and introduced between a pair of laminating rollers 1, 1 that rotate to form a laminated layer with two laminated films膜4。 Film 4.

Here, immediately before the polarizing film 2 and the protective films 3, 3 are introduced into the pair of laminating rollers 1, 1, the adhesive layers 5, 5 are inserted between the polarizing film 2 and the protective films 3, 3 (refer to Figure 2 ). The method for intervening the adhesive layer 5 can be a pattern of coating the adhesive on both sides of the polarizing film 2 or a pattern of coating the adhesive on the surface of the protective films 3 and 3 facing the polarizing film 2. With the adhesive, the polarizing film 2 and the protective films 3 and 3 are bonded together.

When laminating, a pair of laminating rollers 1,1 can be combined with The contact method is set by one of the pressing rollers 6, 6 to press. Here, the pair of pressing rollers 6, 6 are provided on a straight line connecting the pair of bonding rollers 1, 1 and at positions where the bonding rollers 1, 1 are clamped. Then, the pressing rollers 6, 6 are pressed in a direction in which the bonding rollers 1, 1 approach each other. If the pressing rollers 6, 6 are used, it becomes easy to apply uniform weighting in the width direction of the laminating rollers 1, 1, which is preferable. In addition, the pressing roller system does not necessarily have to be a pair, and it may be a state in which one pressing roller is used to press one side of the bonding roller.

Any one of laminating rollers 1, 1 and pressing rollers 6, 6 can be rotated. By rotating at least one of the laminating rollers 1, 1 and the pressing rollers 6, 6 and the laminating rollers 1, 1 are rotated, the polarizing film 2 and the protective films 3, 3 can be laminated and transported. The rollers that are not rotationally driven rotate as the contacted rollers are rotationally driven.

The laminated film 4 after passing through a pair of laminating rollers 1, 1 becomes the polarizing film 2 and the protective film 3, 3 connected by the adhesive layers 5, 5. After that, the laminated film 4 is cured by the adhesive layer 5 to complete the polarizing plate (laminated optical film) 10 shown in FIG. 2.

The polarizing plate 10 is formed by laminating the protective film 3 on both sides of the polarizing film 2 with the adhesive layer 5 interposed therebetween.

The material of the polarizing film 2 can use known materials conventionally used in the manufacture of polarizing plates, such as polyvinyl alcohol resin, polyvinyl acetate resin, ethylene/vinyl acetate (EVA) resin, polyamide resin, and polyester resin. Resin etc. Among them, polyvinyl alcohol-based resins are preferred. Generally, the starting material for the production of the polarizing film 2 is an unstretched film of a polyvinyl alcohol resin film having a thickness of 5 to 100 μm, preferably 10 to 80 μm. The polarizing film 2 can be dyed, boric acid treated, and extended by making this unstretched film Developed by processing.

The thickness of the polarizing film 2 is preferably 3 to 20 μm, more preferably 5 to 18 μm, and even more preferably 7 to 16 μm.

The protective film 3 is a film to prevent cracks or scratches on the main surface or end of the polarizing film 2. Here, among the various films that can be laminated on the polarizing film 2, the "protective film" particularly refers to a film that is physically laminated at the position closest to the polarizing film 2.

The protective film 3 is preferably composed of various transparent resin films known in the field of polarizing plates. Examples include cellulose resins represented by triacetyl cellulose, polyolefin resins represented by polypropylene resins, cyclic olefin resins represented by norbornene resins, and polyolefin resins. Methyl methacrylate resin is a representative example of acrylic resin, and polyethylene terephthalate resin is a representative example of polyester resin. Among them, cellulose resin is representative.

Here, when the protective film is "transparent", it means that the total light transmittance measured in accordance with JIS K 7361 is 70% or more.

The protective films 3 and 3 can be made of the same kind of material or different kinds of materials.

The protective film 3 may be a film without optical functions, or a film with optical functions such as a retardation film or a brightness enhancement film.

The thickness of the protective film 3 is preferably 5 to 30 μm, more preferably 7 to 27 μm, and even more preferably 9 to 25 μm.

As the adhesive, various adhesives conventionally used in the manufacture of polarizing plates can be used. For example, from the viewpoint of weather resistance, refractive index, cationic polymerizability, etc. In terms of points, epoxy resins that do not contain aromatic rings in the molecule are preferred. Moreover, it is preferably cured by irradiation with active energy rays (ultraviolet rays or heat rays).

The epoxy resin is preferably hydrogenated epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, etc., for example. For epoxy resins, polymerization initiators (such as photocationic polymerization initiators for polymerization by ultraviolet radiation, thermal cationic polymerization initiators for polymerization by heat ray irradiation) can be added, and Other additives (sensitizers, etc.) are used to prepare epoxy resin compositions for coating.

In addition, as the adhesive, acrylic resins such as acrylamide, acrylate, urethane acrylate, and epoxy acrylate, or polyvinyl alcohol-based water-based adhesives can also be used.

The polarizing plate 10 is bonded to one side or both sides of a display unit (image display element) such as a liquid crystal cell. The polarizing plate 10 may further include other optical layers laminated on the protective film 3. Other optical layers include, for example, a reflective polarizing film that allows certain polarized light to pass through and reflects polarized light showing the opposite nature; a film with an anti-glare function that has a concave-convex shape on the surface; a film with a surface reflection function; A reflective film with reflective function on the surface; a semi-transmissive reflective film with both reflective and penetrating functions; viewing angle compensation film, etc.

The thickness of the polarizing plate 10 composed of the three layers of the polarizing film 2 and the protective films 3 and 3 is preferably 20 to 100 μm, more preferably 25 to 90 μm, and even more preferably 30 to 80 μm.

Any one of a pair of laminating rollers 1, 1 is the outermost layer made of rubber. The lamination rollers 1, 1 may be composed entirely of rubber, or the center may be composed of metal and only the outermost layer may be composed of rubber. And just In other aspects, the outermost layer of the laminating roller 1 on one side is made of rubber, and the outermost layer of the laminating roller 1 on the other side is made of metal. That is, as long as the outermost layer of at least one of the pair of bonding rollers 1, 1 is made of rubber.

The roll diameter of the laminating roll 1,1 is preferably 50 to 500 mm, more preferably 80 to 450 mm, and even more preferably 100 to 400 mm. When the roll diameter of the bonding rolls 1 and 1 is in such a range, it is easy to apply a sufficient linear pressure to each film during bonding, and it is easy to suppress the generation of wrinkles or bubbles in the laminated film 4.

The thickness of the rubber layer is preferably 1 to 50 mm, more preferably 5 to 40 mm, more preferably 10 to 30 mm, and particularly preferably 10 to 20 mm. If the thickness of the rubber layer is too thin, the influence of the metal roller is strong, and wrinkles etc. are likely to occur in the film during lamination. On the other hand, if the thickness of the rubber layer is too thick, the linear pressure to the laminated films during bonding may be insufficient, and defects such as bubbles may be generated in the laminated film 4. In addition, if the thickness of the rubber layer is too thick, it takes a lot of time to manufacture the rubber roller, which is not economical. In addition, from the viewpoint of adhesion to the metal roller, the rubber layer can be laminated with plural materials with different compositions.

The elastic recovery rate of this rubber is more than 70%. From the viewpoint that it is not easy to cause scratches on the rubber surface during lamination, and the deformation is easy to recover, the elastic recovery rate is preferably 75% or more, more preferably 80% or more, and 85% or more. Better. The upper limit of the elastic recovery rate can be, for example, 99%, 97%, 95%, etc.

Here, "elastic recovery rate" refers to the amount of press-fitting work applied to a member showing plastic deformation and elastic deformation, compared to the The total amount of work, the ratio of elastic deformation.

The elastic recovery rate can be measured using a micro hardness meter (for example, a product name "Fisherscope HM2000", manufactured by Fisher Instruments Co., Ltd.). That is, the Vickers indenter of the square pyramid (made by Zanshi, 136° diagonal) is pressed into the test object from the surface at a load speed of 350mN/10s. After reaching the maximum load of 350mN, the maximum load is maintained for 10s. Thereafter, it can be obtained from the test load and the indentation depth when the Vickers indenter is removed from the surface of the test object at a load removal speed of 350mN/10s.

Specifically, the relationship between the penetration depth (h) when the Vickers indenter is pressed into the test object and the observed test load (F) is shown in the graph, as shown in Figure 3.

Here, h on the horizontal axis represents the length of the part pressed into the test object among the height of the Vickers indenter. From the measurement start point t ₀ , the Vickers indenter is pushed in until it reaches t ₂ through t _1, and after that, when the pressure is released, it reaches t ₃ . The indentation depth h _p at the point t ₃ is less than the value of the indentation depth h _c expected when the relaxation from the point t ₂ is linear. Here, the area surrounded by the points from t ₀ to t ₃ is the amount of work done by plastic deformation (W _plast ), which is the line t ₂ -t ₃ generated when the release of press-in is relaxed, passing through t ₂ and The area enclosed by the h _max line parallel to the vertical axis and the horizontal axis is the amount of work done by elastic deformation (W _elast ).

Here, the elastic recovery rate is the value defined by the elastic recovery rate (%)={W _elast /(W _elast + W _plast )}×100.

The material of the rubber of the outermost layer of the laminating roller 1 may include, for example, NBR (acrylonitrile/butadiene rubber), urethane rubber, silicone rubber, EPDM rubber, butyl rubber, fluoro rubber, and the like.

The rubber hardness of the rubber is preferably 83 to 97° when measured in accordance with JIS K 6253-3 (2012), more preferably 85 to 97°, and even more preferably 85 to 90°. Generally, although the value of rubber hardness tends to be higher, the elastic recovery rate tends to be higher. However, in this embodiment, even if the rubber hardness is within the above range, the elastic recovery rate shows a desired value.

The material of the pressing rollers 6, 6 can be metal or rubber. In the case of rubber, its elastic recovery rate and rubber hardness can be exemplified in the same numerical range as the elastic recovery rate and rubber hardness of the rubber in the laminating roller 1 as preferred values.

The preferable conditions of the pressure applied to the film clamped by the laminating rolls 1, 1 during the lamination are not particularly limited, and 0.01 to 10 MPa is preferred, and 0.1 to 5 MPa is more preferred. When the above pressure is large, defects due to scratches or deformation of the bonding rollers 1, 1 tend to occur. In addition, when the above-mentioned pressure is small, defects such as bubbles and the like tend to be formed without uniform bonding.

The optimal conditions of the tension applied to each film during lamination can vary depending on the film material, lamination temperature, etc., but the film system before lamination is preferably 10 to 1000N/m, and 50 to 500N/m m is better. In addition, the tension applied to the laminated film is preferably 10 to 2000 N/m, and more preferably 100 to 1500 N/m. If the tension is within the above range, it is more difficult to produce wrinkles or slack in the film, and the possibility of stretching or breaking of the film can be reduced.

In the manufacturing method of the polarizing plate 10 described above, the outermost layer of the pair of laminating rollers 1, 1 is rubber, and its elastic recovery rate is more than 70%, so it is difficult to cause scratches or deformation on the laminating rollers 1, 1 . In addition, even if scratches or deformations occur on the bonding rollers 1 and 1, it is difficult to transfer them to the polarizing plate 10. Therefore, according to the manufacturing method of the polarizing plate 10, it is possible to suppress the occurrence of defects in the polarizing plate 10 due to scratches or deformation of the bonding rollers 1, 1.

In particular, the smaller the thickness of the laminated film or the manufactured polarizing plate, the more likely it is to produce defects due to scratches or deformation of the laminating roller. Therefore, this manufacturing method is suitable for laminating films with a small thickness. In addition, the elastic recovery rate and rubber hardness are the above-mentioned values in the lamination of films with a small thickness, thereby easily controlling the appearance of surface defects, streaks, etc.

In addition, in the above-mentioned embodiment, the protective film 3, 3 is attached to both sides of the polarizing film 2 (three-piece bonding), but the protective film 3 may be attached to only one side of the polarizing film 2 Like (two pieces fit).

In addition, in the above-mentioned embodiment, the example in which the first optical film is the polarizing film 2 and the second optical film are the protective films 3 and 3 is shown, but these may be other types of films. In addition, the film system attached to both sides of the polarizing film 2 does not necessarily need to be the same kind of film, but may be another kind of film.

<Second Embodiment>

The second embodiment shows an example in which a polarizing plate as a first optical film and another optical film as a second optical film are bonded together to produce a "adhesive polarizing plate" as a laminated optical film. Hereinafter, the differences from the first embodiment will be explained.

As shown in FIG. 4(a), the adhesive-attached polarizing plate 20A manufactured by the manufacturing method of this embodiment is formed on one side of the polarizing plate 10 manufactured in the first embodiment through the adhesive layer 7 A temporary protective film (second optical film) 8 is laminated.

The temporary protective film 8 is a film that can be peeled off from the laminated polarizing plate 10, and is a film for protecting the surface of the protective film 3 on which the temporary protective film 8 has been laminated from damage, abrasion, etc. The material of the temporary protective film 8 is preferably polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and polybutylene terephthalate. , The same thing as the protective film 3 can also be used. As long as it has the necessary strength and optical compatibility, other plastic films can be used, such as polyolefin film, polyacetate film, polycarbonate film, polyphenylene sulfide film, polyamide film, and polychloride Ethylene film, ethylene-vinyl acetate copolymer film, various liquid crystal polymer films, etc.

The temporary protective film 8 is laminated to the protective film 3 after being laminated on the protective film 3 until the time of use of the polarizing plate 20A with the adhesive, and is peeled off from the protective film 3 during use. At this time, the adhesive layer 7 is peeled off from the polarizing plate 10 side in a state of being attached to the temporary protective film 8 side.

The thickness of the temporary protective film 8 is preferably 5 to 70 μm, more preferably 10 to 60 μm, and even more preferably 15 to 50 μm.

The adhesive layer 7 may be composed of acrylic resin, or silicone resin, polyester, polyurethane, polyether, or the like.

The thickness of the adhesive layer 7 is preferably 2 to 40 μm, and more preferably 4 to 25 μm.

The method of providing the adhesive layer 7 can be, for example, using various adhesives such as acrylic one-component or two-component adhesives, rubber-based adhesives, and silicone-based adhesives on the temporary protective film 8. The method of laminating the protective film 3 after the adhesive layer 7 is formed is usually the one that is temporarily wound into a roll with a peeling film coated on the adhesive layer. The peeling film was peeled off before bonding (two-piece bonding) and used. In addition, it may be a method of applying a solution containing the above-mentioned resin and optional additional components to the protective film 3 of the polarizing plate 10. After the adhesive layer 7 is provided, the polarizing plate 10 and the temporary protective film 8 are bonded by one pair of bonding rollers as shown in FIG. 1 (two-piece bonding) to manufacture the polarizing plate 20A with the adhesive.

Even in this embodiment, it is possible to suppress the occurrence of defects due to scratches or deformation of the bonding rollers 1, 1 on the polarizing plate 20A with the adhesive.

In the above-mentioned system, an example in which the second optical film is the temporary protective film 8 is shown, but the second optical film system may be a separation film 9 instead of the temporary protective film 8 as shown in FIG. 4(b).

The separation film 9 is a peelable film attached for the purpose of protecting the adhesive layer 7 or preventing foreign matter from adhering. When the polarizing plate 20B with the adhesive is used, the separation film 9 is peeled to expose the adhesive layer 7. The separation membrane 9 may be composed of, for example, polyethylene resins such as polyethylene, polypropylene resins such as polypropylene, polyester resins such as polyethylene terephthalate, and the like. Among them, a stretched film of polyethylene terephthalate is preferred.

The adhesive layer 7 in which the separation film 9 is laminated is a layer that functions when attaching the polarizing plate 10 to other articles (for example, a liquid crystal cell or a touch panel). The material of the adhesive layer 7 can be the same material as when the temporary protective film 8 is laminated.

Regarding the separation film 9, in order to be easily peeled off when the polarizer 20B with an adhesive is used, the surface contacting the adhesive layer 7 may be subjected to a release treatment with silicone resin or the like. When the separation film 9 is peeled off, the adhesive layer 7 will remain on the polarizing plate 10 side.

The thickness of the separation membrane 9 is preferably 5 to 70 μm, more preferably 10 to 60 μm, and even more preferably 15 to 50 μm.

In addition, in the present embodiment, the polarizer 10 is further provided with a temporary protective film 8 or an example of the polarizing plates 20A and 20B of the separating film 9 with adhesive, but the polarizing plates 20A, 20B with adhesive may also be provided with temporary protective films 8 and separation membrane 9.

As mentioned above, although the suitable embodiment of this invention was described, this invention is not limited at all by the said embodiment. For example, in the above-mentioned embodiment, the first optical film is a film having polarizing properties as an example, but other optical films that do not have polarizing properties may be targeted.

[Example]

Hereinafter, examples and comparative examples are listed to more specifically describe the content of the present invention. In addition, the present invention is not limited by the following examples.

The film used is as follows.

‧Polarizing film: Polyvinyl alcohol resin film (trade name "VF-PE # 3000", manufactured by Kuraray Co., Ltd.) is dyed with iodine, stretched, and dried. The thickness is 12μm.

‧Protection film A...Triacetyl cellulose film (trade name "Konica Minolta Optical Film KC2UAW", manufactured by Konica Minolta Advanced Layers Co., Ltd.). The thickness is 25μm.

‧Protective film B... Cyclic olefin resin film (trade name "Zeonor Film ZF14-23", manufactured by Zeon Co., Ltd.). The thickness is 23μm.

‧Temporary protective film with adhesive...a film composed of a base film of polyethylene terephthalate and an adhesive layer of acrylic resin (trade name "AS3-304(19)", manufactured by Fujimori Industry Co., Ltd.). The thickness is 58μm (the thickness of only the base film from which the adhesive layer has been removed is 38μm).

‧Separation membrane with adhesive... a membrane composed of a separation membrane of polyethylene terephthalate subjected to a release treatment and an acrylic resin adhesive (trade name "# L2-NCF", Lintec shares Limited company). The thickness is 43 μm (the thickness of only the separation film from which the adhesive layer has been removed is 38 μm).

The adhesive system is prepared as follows. In 100 parts by weight of water, 4 parts by weight of polyvinyl alcohol (trade name "Gohsefimer Z-200", manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and sodium glyoxylate (trade name " SPM-01", manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 4 parts by weight to prepare a water-based adhesive.

The rubber material used for the laminating roller and the pressing roller is made by the following method.

The NBR polymer, sulfur, silicon dioxide, and phthalic acid-based plasticizer are measured in a predetermined weight ratio, kneaded with a kneader, and then molded into a roll by sheet molding. The composition of the produced rubber material is set to the following weight ratio.

‧Rubber material A

NBR polymer: sulfur: silicon dioxide: phthalic acid plasticizer=100:12:60:9

‧Rubber material B

NBR polymer: sulfur: silicon dioxide: phthalic acid plasticizer=100:7:60:8

‧Rubber material C

NBR polymer: sulfur: silicon dioxide: phthalic acid plasticizer=100:8:70:3

Table 1 shows the elastic recovery rate (%) and hardness (°) of the produced rubber material.

The rollers used are as follows.

‧Laminating roller made of rubber on the outermost layer...The overall diameter of the roller is 300mm, and the thickness of the rubber material on the outermost layer is 16.5mm. As the rubber material, the above rubber materials A, B, and C are used.

‧Metal roller... made of stainless steel.

‧Press roller...The rubber material is the above rubber material A.

(Examples 1 and 2)

Using the laminating roller shown in Table 1, the protective film A was stuck on one side of the polarizing film, and the protective film B was stuck on the other side (three-piece bonding) to obtain a polarizing plate. At this time, the adhesive is applied to the polarizing film side. The thickness of the obtained polarizer is 60 μm.

(Example 3)

Using the bonding roller shown in Table 1, the polarizing plate manufactured in Example 1 and the temporary protective film with adhesive were bonded (two-piece bonding) to obtain a polarizing plate with adhesive.

(Example 4)

Using the laminating roller shown in Table 1, the polarizing plate manufactured in Example 1 and the adhesive-attached separation film were attached (two-piece laminating) to obtain the adhesive bias Light board.

(Example 5)

Using the laminating roller shown in Table 1, the protective film A was stuck on one side of the polarizing film, and the protective film B was stuck on the other side (three-piece bonding) to obtain a polarizing plate. At this time, the adhesive is applied to the polarizing film side. In addition, the metal roller was pressed against the rubber roller side using a pressing roller. The thickness of the obtained polarizer is 60 μm.

(Comparative example 1)

Using the laminating roller shown in Table 1, the protective film A was stuck on one side of the polarizing film, and the protective film B was stuck on the other side (three-piece bonding) to obtain a polarizing plate. At this time, the adhesive is applied to the polarizing film side. The thickness of the obtained polarizer is 60 μm.

The surfaces of the polarizing plates obtained in Examples 1 to 5 and Comparative Example 1 and the polarizing plate with adhesive were visually observed. The results are shown in Table 1.

‧Evaluation mark

A... No defects can be seen.

B...Slightly seen defects (within the allowable range) that are considered to be scratches or deformations of the bonding roller being transferred.

C... I saw a lot of defects that were considered to be scratches or deformations of the bonding roller and were transferred.

1‧‧‧Laminating roller

2‧‧‧Polarizing film (first optical film)

3‧‧‧Protection Film (Second Optical Film)

4‧‧‧Laminated film

6‧‧‧Press roller

Claims (9)

A method for manufacturing a laminated optical film, in which a first optical film is introduced between a pair of laminating rolls that are rotated, and an adhesive layer or an adhesive layer is interposed on one or both sides of the first optical film The second optical film is arranged to bond the first optical film and the second optical film, wherein the outermost layer of at least one of the bonding rollers in the pair of bonding rollers is rubber, and the elasticity of the rubber The recovery rate is more than 70%. The material of the aforementioned rubber is NBR, urethane rubber, silicone rubber, EPDM rubber, butyl rubber, or fluorine rubber. The rubber hardness of the aforementioned rubber measured in accordance with JIS K 6253 is 83 to 97°. The manufacturing method of the laminated optical film described in the first item of the patent application, wherein at least one of the second optical films is a transparent film. The manufacturing method of the laminated optical film as described in the second item of the scope of patent application, wherein the transparent film is a protective film and the first optical film is a polarizing film. The manufacturing method of the laminated optical film described in the scope of patent application 3, wherein the polarizing film contains a polyvinyl alcohol-based resin. The method for manufacturing a laminated optical film as described in item 3 or 4 of the scope of patent application, wherein the thickness of the polarizing film is 20 μm or less, the thickness of the protective film is 30 μm or less, and the thickness of the laminated optical film is 100 μm or less. Manufacturer of laminated optical film as described in item 2 of the scope of patent application A method in which the first optical film is provided with a polarizing plate including a polarizing film and a protective film, and the manufacturing method is to bond the first optical film and the second optical film via the adhesive layer. The method for manufacturing a laminated optical film as described in claim 6 wherein the thickness of the polarizing film is 20 μm or less, the thickness of the protective film is 30 μm or less, and the thickness of the polarizing plate is 100 μm or less. The method for manufacturing a laminated optical film as described in any one of items 1 to 4 of the scope of the patent application, wherein any one of the aforementioned pair of laminating rollers is the outermost layer of rubber, and the elastic recovery rate of the aforementioned rubber More than 70%. The method for manufacturing a laminated optical film as described in any one of items 1 to 4 of the scope of the patent application, wherein at least one pressing roller is brought into contact with at least one of the aforementioned pair of laminating rollers, The bonding roller is pressed in a direction in which the pair of bonding rollers approach each other.

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