TW201739624A - Method for manufacturing laminated optical film - Google Patents

Abstract

The present invention provides a method for producing a laminated optical film which can suppress defects in the laminated optical film caused by scratching or deformation of the bonding roller. In the method for producing a laminated optical film of the present invention, the first optical film 2 is introduced between the one pair of the bonding rolls 1, 1 and the one side or both sides of the first optical film 2 are interposed. The second optical film 3, which is disposed next to the agent layer or the adhesive layer, is bonded to the first optical film 2 and the second optical film 3. The outermost layer of at least one of the pair of bonding rolls 1 and 1 is rubber, and the elastic recovery rate of the rubber is 70% or more. Therefore, the bonding roller 1 is less likely to be scratched. The deformation of the roll 1 is easy to recover.

Description

Method for manufacturing laminated optical film

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

Conventionally, a polarizing plate has been known as one of optical components such as a liquid crystal display device. The polarizing plate generally has a protective film laminated on one side or both sides of the polarizing film, and reinforced the mechanical strength, thermal stability, water resistance and the like of the polarizing film.

As a method of laminating a polarizing film and a 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 using one of the roll faces as a rubber.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5399890

In general, when the optical film is bonded to each other by using a bonding roller, if the bonding roller is scratched or deformed, the shape is transferred to the optical film, and a defective laminated optical film is produced.

Accordingly, an object of the present invention is to provide a method for producing a laminated optical film which can suppress defects in a laminated optical film due to scratching or deformation of a bonding roll.

In the method for producing a laminated optical film of the present invention, a first optical film is introduced between one of the pair of bonding rolls, and an adhesive layer or an adhesive is interposed between the one surface side or both sides of the first optical film. a second optical film disposed in a layer of a pressure sensitive adhesive, wherein the first optical film and the second optical film are bonded to each other, wherein at least one of the pair of bonding rolls is made of rubber, rubber The elastic recovery rate is 70% or more.

In the method for producing a laminated optical film, at least one of the pair of bonding rolls has rubber as the outermost layer of the bonding roller, and the elastic recovery rate of the rubber is 70% or more, so that the bonding roller is less likely to be scratched. The deformation of the bonding roller is easy to recover. Therefore, by the method for producing the laminated optical film, it is possible to suppress the occurrence of defects in the laminated optical film due to scratching or deformation of the bonding roller.

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

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

In the method for producing a laminated optical film, 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 laminated optical film may be 100 μm or less. In general, the smaller the thickness of the laminated optical film, the more likely the defect due to scratching or deformation of the bonding roller, so that each film having the thickness can be said to be suitable for the application of the present invention.

In another aspect of the method for producing a laminated optical film, the first optical film includes a polarizing film and a polarizing plate of a protective film, and the first optical film and the second optical film can be bonded together 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 may be 83 to 97°. Even if the rubber hardness is this, if the elastic recovery rate satisfies the above value, the effect of the present invention can be exerted.

In any of the above manufacturing methods, any one of the pair of bonding rolls may be rubbery at the outermost layer, and the elastic recovery rate of the rubber may be 70% or more. At this time, the effects of the present invention can be further exerted.

In any of the above manufacturing methods, at least one of the pressing rolls may be brought into contact with at least one of the pair of bonding rolls, and the bonding rolls may be moved toward each other in a direction in which the pair of bonding rolls approach each other. Pressure. At this time, it is easy to apply a uniform weight to the width direction of the bonding roller, which is preferable.

According to the present invention, it is possible to provide a method for producing a laminated optical film which can suppress the occurrence of defects in the laminated optical film due to scratching or deformation of the bonding roller.

1‧‧‧Fitting roller

2‧‧‧ polarizing film (first optical film)

3‧‧‧Protective film (2nd optical film)

4‧‧‧ laminated film

5‧‧‧ adhesive layer

6‧‧‧ Pressing roller

7‧‧‧Adhesive layer

8‧‧‧ Temporary protective film (2nd optical film)

9‧‧‧Separation membrane (2nd optical film)

10‧‧‧Polar plate (layered optical film, first optical film)

20A, 20B‧‧‧ polarizing plate with adhesive (laminated optical film)

Fig. 1 is a view showing a state in which each film is bonded by a pair of bonding rolls.

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

Fig. 3 is an explanatory diagram of a method of determining the elastic recovery rate.

Fig. 4(a) is a cross-sectional view showing a polarizing plate with an adhesive according to a second embodiment. Fig. 4(b) is a cross-sectional view showing another polarizing plate with an adhesive according to the second embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals are given to the same or corresponding parts, and the description of the same is omitted. Moreover, the dimensional ratio of each drawing does not necessarily coincide with the actual one, and in particular, the thickness is exaggerated.

<First embodiment>

In the first embodiment, a polarizing film as a laminated optical film is produced by laminating a polarizing film as a first optical film and a protective film as a second optical film.

As shown in Fig. 1, the polarizing film 2 and the protective films 3, 3 disposed on both sides thereof are introduced and transferred between the pair of bonding rolls 1, 1 to form a laminated layer of two films. Membrane 4.

Here, before the polarizing film 2 and the protective films 3, 3 are introduced into the pair of bonding rolls 1, 1, the adhesive layers 5, 5 are interposed between the polarizing film 2 and the protective films 3, 3 (refer to Fig. 2). ). The method of interposing the adhesive layer 5 may be a pattern in which an adhesive is applied to both surfaces of the polarizing film 2, or a pattern in which an adhesive is applied to the surface of the protective film 3, 3 facing the polarizing film 2. The polarizing film 2 and the protective films 3, 3 are bonded by an adhesive.

When fitted, a pair of bonding rolls 1, 1 can be used by One of the ways in which it is contacted is pressed against the pressing rolls 6, 6. Here, the pair of pressing rolls 6, 6 are provided on the straight line connecting the pair of bonding rolls 1, 1 and sandwiching the bonding rolls 1, 1. Then, the pressing rolls 6, 6 are pressed in a direction in which the bonding rolls 1, 1 approach each other. When the pressing rolls 6, 6 are used, it is easy to apply uniform weighting in the width direction of the bonding roll 1, and it is preferable. Moreover, the pressing roller system is not necessarily in pairs, and may be a state in which one of the pressing rollers is pressed by one pressing roller.

Any one of the bonding rolls 1, 1 and the pressing rolls 6, 6 can be rotated. At least one of the bonding rolls 1, 1 and the pressing rolls 6, 6 is rotationally driven, and the bonding rolls 1, 1 are rotated, and the polarizing film 2 and the protective films 3, 3 can be bonded and conveyed. The roller that is not rotationally driven rotates as the roller being contacted is rotationally driven.

The laminated film 4 after passing through the pair of bonding rolls 1, 1 becomes the polarizing film 2 and the protective film 3, 3 by the adhesive layers 5, 5. After the buildup film 4 is cured, the adhesive layer 5 is cured, and the polarizing plate (layered optical film) 10 shown in FIG. 2 is completed.

The polarizing plate 10 is formed by laminating the protective film 3 on both surfaces of the polarizing film 2 via the adhesive layer 5.

As the material of the polarizing film 2, a known material which is conventionally used for the production of a polarizing plate can be used, and examples thereof include a polyvinyl alcohol resin, a polyvinyl acetate resin, an ethylene/vinyl acetate (EVA) resin, a polyamide resin, and a polyester system. Resin, etc. Among them, a polyvinyl alcohol-based resin is preferred. In general, the starting material for the production of the polarizing film 2 is, for example, an unstretched film of a polyvinyl alcohol-based 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 delayed by the unstretched film. Stretched and processed.

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

The protective film 3 is a film that prevents cracking or scratching of the main surface or the end portion of the polarizing film 2. Here, among the various films which can be laminated on the polarizing film 2, the "protective film" means, in particular, a film which 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 from the field of polarizing plates. For example, a cellulose resin represented by triethyl fluorenyl cellulose, a polyolefin resin represented by a polypropylene resin, a cyclic olefin resin represented by a norbornene resin, and a poly The methyl methacrylate resin is a representative example of an acrylic resin, and a polyethylene terephthalate resin is a representative polyester resin. Among them, cellulose-based resins are representative.

Here, when the protective film is "transparent", the total light transmittance measured according to JIS K 7361 is 70% or more.

The protective films 3, 3 may be composed of the same kind of material, or may be composed of different materials.

The protective film 3 may be a film having no optical function, or may be a film having an optical function 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, still more preferably 9 to 25 μm.

As the subsequent agent, various adhesives conventionally used in the production of polarizing plates can be used. For example, from the viewpoints of weather resistance, refractive index, and cationic polymerization In view of the above, an epoxy resin containing no aromatic ring in the molecule is preferred. Further, it is preferably cured by irradiation with an active energy ray (ultraviolet rays or hot wires).

The epoxy resin is preferably a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin or the like. For the epoxy resin, a polymerization initiator (for example, a photocationic polymerization initiator for polymerization by irradiation with ultraviolet rays, a thermal cationic polymerization initiator for polymerization by heat irradiation), and Other additives (sensitizing agents, etc.) are used to prepare an epoxy resin composition for coating.

Further, as the adhesive, an acrylic resin such as acrylamide, acrylate, urethane acrylate or epoxy acrylate, or a polyvinyl alcohol-based water-based adhesive can 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 contain other optical layers laminated on the protective film 3. The other optical layer may, for example, be a reflective polarizing film that transmits a certain polarized light and reflects a polarized light having an opposite property; a film with an anti-glare function having a concave-convex shape on the surface; a film with a surface anti-reflective function; A reflective film having a reflective function on the surface; a semi-transmissive reflective film having both a reflecting function and a penetrating function; a viewing angle compensation film.

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

Any one of the pair of bonding rolls 1, 1 is made of rubber. The bonding rolls 1, 1 may be constructed entirely of rubber, or the center portion may be made of metal and the outermost layer may be made of rubber. Again, In other aspects, the outermost layer of one of the bonding rolls 1 may be made of rubber, and the outermost layer of the other bonding roll 1 may be made of metal. In other words, at least one of the pair of bonding rolls 1, 1 may be made of rubber.

The roll diameter of the bonding rolls 1, 1 is preferably 50 to 500 mm, more preferably 80 to 450 mm, still 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 sufficiently apply a line pressure to each film at the time of bonding, and it is easy to suppress generation of wrinkles, bubbles, and the like in the laminated film 4.

The thickness of the rubber layer is preferably from 1 to 50 mm, more preferably from 5 to 40 mm, still more preferably from 10 to 30 mm, and particularly preferably from 10 to 20 mm. If the thickness of the rubber layer is too thin, the influence of the metal roll is strong, and wrinkles are likely to occur in the film at the time of bonding. On the other hand, when the thickness of the rubber layer is too thick, there is a case where the line pressure of each film of the laminated layer is insufficient at the time of bonding, and defects such as bubbles are generated in the laminated film 4. Further, if the thickness of the rubber layer is too thick, it is not economically good because of the time required to manufacture the rubber roller. Further, from the viewpoint of adhesion to the metal roll, the rubber layer can be formed into a plurality of materials having different compositions.

The elastic recovery rate of the rubber is 70% or more. From the viewpoint that the rubber surface is less likely to be scratched at the time of bonding, and the deformation generated is easily recovered, the elastic recovery ratio is preferably 75% or more, more preferably 80% or more, and 85% or more. Better. The upper limit of the elastic recovery rate may be, for example, 99%, 97%, 95% or the like.

Here, the "elastic recovery rate" refers to the fact that when the amount of work is given to the member exhibiting plastic deformation and elastic deformation, the deformation is based on the two deformations. The total amount of work done, the ratio of the elastic deformation involved.

The elastic recovery rate can be measured using a micro hardness tester (for example, the product name "Fisherscope HM2000", manufactured by Fisher Instruments Co., Ltd.). That is, the Vickers indenter of the regular square pyramid (Zanshi system, opposite angle 136°) is pressed from the surface at a load speed of 350 mN/10 s for the test object, and after reaching the maximum load of 350 mN, it is maintained for 10 s in the state of maximum load load. Thereafter, the test load and the indentation depth at which the Vickers indenter is removed from the surface of the test object at a decoupling speed of 350 mN/10 s can be obtained.

Specifically, the relationship between the indentation depth (h) when the Vickers indenter is pressed into the test object and the magnitude (F) of the observed test load is shown in Fig. 3 as shown in Fig. 3.

Here, h on the horizontal axis represents the length of the portion of the Vickers indenter that is pressed into the test object. The Vickers indenter is pushed in from t ₁ and reaches t ₂ from the measurement start point t ₀ , and then, when the press is released, t _{3 is} reached. The indentation depth h _p of the t ₃ point is smaller than the value of the indentation depth h _c expected when the relaxation from the t ₂ point is a line type. Here, the region surrounded by each point of t ₀ to t ₃ is the work amount of plastic deformation (W _plast ), which is generated by the t ₂ -t ₃ line which is generated when the press-in is released, and passes through t ₂ and The h _max line parallel to the longitudinal axis and the area surrounded by the horizontal axis are the work of elastic deformation (W _elast ).

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

The material of the rubber of the outermost layer of the bonding roll 1 may, for example, be NBR (acrylonitrile/butadiene rubber), urethane rubber, polyoxyethylene rubber, EPDM rubber, butyl rubber, fluororubber or the like.

The rubber hardness of the rubber is preferably 83 to 97°, more preferably 85 to 97°, still more preferably 85 to 90°, as measured according to JIS K 6253-3 (2012). In general, the smaller the value of the rubber hardness, the higher the elastic recovery rate. However, in the present embodiment, even if the rubber hardness is within the above range, the elastic recovery ratio shows a desired value.

The material of the pressing rolls 6, 6 may be metal or rubber. In the case of rubber, the elastic recovery ratio and the rubber hardness can be exemplified as the same as the elastic recovery ratio of the rubber in the bonding roll 1 and the rubber hardness.

The preferable conditions for the pressure applied to the film sandwiched by the bonding rolls 1, 1 at the time of bonding are not particularly limited, and are preferably 0.01 to 10 MPa, more preferably 0.1 to 5 MPa. When the above pressure is large, there is a tendency that defects due to scratches or deformation of the bonding rolls 1, 1 are liable to occur. Further, when the pressure is small, there is a tendency that the defects are not uniformly adhered and bubbles or the like are easily generated.

The preferable conditions for the tension applied to each film at the time of bonding may vary depending on the material of the film, the bonding temperature, etc., but the film before bonding is preferably 10 to 1000 N/m, preferably 50 to 500 N/ m is better. Further, the tension applied to the film after bonding is preferably from 10 to 2,000 N/m, more preferably from 100 to 1,500 N/m. If the tension is within the above range, it is more difficult to cause wrinkles or slack in the film, and the possibility of film stretching or cracking can be further reduced.

In the method of manufacturing the polarizing plate 10 described above, the outermost layer of the pair of bonding rolls 1, 1 is rubber, and the elastic recovery rate is 70% or more, so that the bonding rolls 1, 1 are less likely to be scratched or deformed. . Further, even if the bonding rolls 1, 1 are scratched or deformed, 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 rolls 1, 1.

In particular, the smaller the thickness of the bonded film or the manufactured polarizing plate, the more likely the defect due to scratching or deformation of the bonding roller is. Therefore, the manufacturing method is suitable for bonding a film having a small thickness. Moreover, in the bonding of the film having a small thickness, the elastic recovery ratio and the rubber hardness are set to the above values, whereby the appearance of surface defects, streaks, and the like can be easily controlled satisfactorily.

In the above embodiment, the protective film 3, 3 is bonded to both surfaces of the polarizing film 2 (three-piece bonding), but the protective film 3 may be bonded to only one side of the polarizing film 2. Sample (two pieces fit).

Further, in the above embodiment, the first optical film is the polarizing film 2 and the second optical film is the protective film 3, 3, but these may be other types of films. Further, the film system bonded to both surfaces of the polarizing film 2 does not necessarily need to be the same type of film, and may be a film of another type.

<Second embodiment>

In the second embodiment, the polarizing plate as the first optical film and the other optical film as the second optical film are bonded together to produce an "adhesive-attached polarizing plate" as a laminated optical film. Hereinafter, differences from the first embodiment will be described.

As shown in Fig. 4(a), the polarizing plate 20A with an adhesive produced by the manufacturing method of the present embodiment is adhered to the single surface of the polarizing plate 10 manufactured in the first embodiment via the adhesive layer 7. The temporary protective film (second optical film) 8 was bonded.

The temporary protective film 8 is a film which can be peeled off from the polarizing plate 10 laminated thereon, and is used to protect the surface of the protective film 3 on which the temporary protective film 8 has been laminated from being damaged, worn, or the like. The material of the temporary protective film 8 is preferably a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate or polybutylene terephthalate. The same as the protective film 3 can also be used. As long as it has the necessary strength and optical suitability, other plastic films such as polyolefin film, polyacetate film, polycarbonate film, polyphenylene sulfide film, polyamide film, polychlorinated chlorine can be used. A vinyl film, an ethylene-vinyl acetate copolymer film, various liquid crystal polymer films, and the like.

After the temporary protective film 8 is laminated on the protective film 3, it is bonded to the protective film 3 until the polarizing plate 20A to which the adhesive is applied, and is peeled off from the protective film 3 at the time of use. At this time, the adhesive layer 7 is peeled off from the side of the polarizing plate 10 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, still more preferably 15 to 50 μm.

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

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

The method of providing the adhesive layer 7 may be, for example, using an acrylic one-liquid type or two-liquid type adhesive, a rubber-based adhesive, or a polyoxyn-based adhesive as the temporary protective film 8. The method of laminating the protective film 3 after the formation of the adhesive layer 7 is usually carried out by temporarily taking up the roll film from the state in which the release film is coated on the adhesive layer. The release film was peeled off before being bonded (two-piece bonding) and used. Further, a method of applying a solution containing the above resin and an optional additive component to the protective film 3 of the polarizing plate 10 may be employed. After the adhesive layer 7 is provided, the polarizing plate 10 and the temporary protective film 8 are bonded to the bonding roller as shown in Fig. 1 (two sheets are bonded together) to produce a polarizing plate 20A with an adhesive.

Even in the present embodiment, it is possible to suppress the occurrence of defects due to scratches or deformation of the bonding rolls 1, 1 in the polarizing plate 20A to which the adhesive is applied.

In the above, the second optical film is an example of the temporary protective film 8, but the second optical film is a separation film 9 instead of the temporary protective film 8 as shown in Fig. 4(b).

The separation membrane 9 is a peelable film that is attached for the purpose of protecting the adhesive layer 7 or preventing adhesion of foreign matter, and is peeled off when the polarizing plate 20B with an adhesive is used to expose the adhesive layer 7. The separation membrane 9 can be composed of, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, or a polyester resin such as polyethylene terephthalate. Among them, a stretch film of polyethylene terephthalate is preferred.

The adhesive layer 7 in which the separation film 9 is laminated is a layer that functions when the polarizing plate 10 is attached to another article such as a liquid crystal cell or a touch panel. As the material of the adhesive layer 7, the same material as that of the temporary protective film 8 can be used.

The separation membrane 9 can be easily peeled off when the polarizing plate 20B with an adhesive is used, and the surface to be contacted with the adhesive layer 7 can be subjected to a release treatment by a polyoxymethylene resin or the like. When the separation membrane 9 is peeled off, the adhesive layer 7 remains on the side of the polarizing plate 10.

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

In the present embodiment, the polarizing plate 10 further includes the polarizing plates 20A and 20B with the adhesive for the temporary protective film 8 or the separation film 9, but the polarizing plates 20A and 20B with the adhesive may also have a temporary protective film. 8 and both of the separation membranes 9.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiment, the first optical film is exemplified by a film having a polarizing property, but another optical film having no polarizing property may be used.

[Examples]

Hereinafter, the contents of the present invention will be more specifically described by way of examples and comparative examples. Further, the present invention is not limited by the following examples.

The film used is as follows.

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

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

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

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

‧Separation film with adhesive...film consisting of a polyethylene terephthalate separation membrane and an acrylic resin adhesive (trade name "# L2-NCF", Lintec) Limited company). The thickness was 43 μm (the thickness of only the separation membrane from which the adhesive layer had been removed was 38 μm).

The subsequent agent is prepared in the following manner. 4 parts by weight of ethyl acetonitrile-modified polyvinyl alcohol (trade name "Gohsefimer Z-200", manufactured by Nippon Synthetic Chemical Co., Ltd.) and sodium glyoxylate (product name) in 100 parts by weight of water 4 parts by weight of SPM-01", manufactured by Nippon Synthetic Chemical Industry Co., Ltd., and a water-based adhesive was prepared.

The rubber material used for the bonding roller and the pressing roller was produced in the following manner.

The NBR polymer, sulfur, cerium oxide, and citric acid plasticizer are metered so as to have a predetermined weight ratio, and after kneading by a kneading machine, they are formed into a roll by sheet molding. The composition of the rubber material produced was set to the following weight ratio.

‧Rubber material A

NMR polymer: sulfur: cerium oxide: phthalic acid plasticizer = 100:12:60:9

‧Rubber material B

NMR polymer: sulfur: cerium oxide: phthalic acid plasticizer = 100:7:60:8

‧Rubber material C

NMR polymer: sulfur: cerium oxide: phthalic acid plasticizer = 100:8:70:3

The elastic recovery ratio (%) and hardness (°) of the rubber material produced are shown in Table 1.

The rolls used are as follows.

‧The outermost layer is made of rubber. The roll diameter of the whole is 300mm, and the thickness of the rubber material at the outermost layer is 16.5mm. The rubber materials are the above-mentioned rubber materials A, B, and C.

‧ metal roll... made of stainless steel.

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

(Examples 1 and 2)

Using the bonding rolls shown in Table 1, the protective film A was bonded to one surface of the polarizing film, and the protective film B (three-piece bonding) was bonded to the other surface to obtain a polarizing plate. At this time, the adhesive agent was applied to the polarizing film side. The thickness of the obtained polarizing plate was 60 μm.

(Example 3)

Using the bonding rolls shown in Table 1, the polarizing plate produced in Example 1 and the temporary protective film with an adhesive were bonded (two sheets were bonded) to obtain a polarizing plate with an adhesive.

(Example 4)

Using the bonding rolls shown in Table 1, the polarizing plate produced in Example 1 and the separation film with an adhesive attached were bonded together (two sheets were bonded) to obtain a biasing agent. Light board.

(Example 5)

Using the bonding rolls shown in Table 1, the protective film A was bonded to one surface of the polarizing film, and the protective film B (three-piece bonding) was bonded to the other surface to obtain a polarizing plate. At this time, the adhesive agent was applied to the polarizing film side. Further, the metal roller was pressed against the rubber roller side by using a pressing roller. The thickness of the obtained polarizing plate was 60 μm.

(Comparative Example 1)

Using the bonding rolls shown in Table 1, the protective film A was bonded to one surface of the polarizing film, and the protective film B (three-piece bonding) was bonded to the other surface to obtain a polarizing plate. At this time, the adhesive agent was applied to the polarizing film side. The thickness of the obtained polarizing plate was 60 μm.

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

‧ evaluation mark

A... I can't see the defect.

B... I saw a slight flaw in the scratch or deformation of the bonding roller (within the allowable range).

C... I saw that many of them were defects in which the scratch or deformation of the bonding roller was transferred.

1‧‧‧Fitting roller

2‧‧‧ polarizing film (first optical film)

3‧‧‧Protective film (2nd optical film)

4‧‧‧ laminated film

6‧‧‧ Pressing roller

Claims (10)

A method for producing a laminated optical film, wherein a first optical film is introduced between one of the pair of bonding rolls, and an adhesive layer or an adhesive layer is interposed between one side or both sides of the first optical film. In the second optical film, the first optical film and the second optical film are bonded to each other, and at least one of the pair of bonding rolls is made of rubber, and the rubber is elastic. The response rate is over 70%. The method for producing a laminated optical film according to the first aspect of the invention, wherein at least one of the second optical films is a transparent film. The method for producing a laminated optical film according to the second aspect of the invention, wherein the transparent film is a protective film, and the first optical film is a polarizing film. The method for producing a laminated optical film according to claim 3, wherein the polarizing film contains a polyvinyl alcohol-based resin. The method for producing a laminated optical film according to the third aspect of the invention, 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. The method for producing a laminated optical film according to the second aspect of the invention, wherein the first optical film includes a polarizing film and a protective film, and the manufacturing method is the first optical film and the second optical The film is bonded to each other via the above-mentioned adhesive layer. The method for producing a laminated optical film according to claim 6, wherein the polarizing film has a thickness of 20 μm or less, the protective film has a thickness of 30 μm or less, and the polarizing plate has a thickness of 100 μm or less. The method for producing a laminated optical film according to any one of claims 1 to 7, wherein the rubber hardness of the rubber measured in accordance with JIS K 6253 is 83 to 97°. The method for producing a laminated optical film according to any one of the first to eighth aspect, wherein the one of the pair of bonding rolls is a rubber outermost layer, and the elastic recovery rate of the rubber is More than 70%. The method for producing a laminated optical film according to any one of claims 1 to 9, wherein at least one of the pressing rolls contacts at least one of the pair of bonding rolls, The bonding roller is pressed in a direction in which the pair of bonding rollers approach each other.