JP6378731B2 - Method for producing laminated optical film - Google Patents

Description

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

  Conventionally, a polarizing plate is known as one of optical components constituting a liquid crystal display device or the like. In general, a polarizing film has a protective film laminated on one side or both sides of a polarizing film, and the mechanical strength, thermal stability, water resistance and the like of the polarizing film are supplemented.

  As a method for laminating a polarizing film and a protective film, a method of bonding with a pair of bonding rolls is known. For example, in Patent Document 1, both films are bonded using a pair of rubber rolls whose roll surface is rubber.

Japanese Patent No. 5399890

  In general, when optical films are bonded using a bonding roll, if the bonding roll has scratches or deformation, these shapes are transferred to the optical film, and a defective laminated optical film is produced.

  Then, an object of this invention is to provide the manufacturing method of the laminated optical film which can suppress that the defect based on the damage | wound of a bonding roll and a deformation | transformation generate | occur | produces in a laminated optical film.

  In the present invention, the first optical film and the second optical element disposed on one or both sides of the first optical film via an adhesive layer or an adhesive layer between a pair of rotating bonding rolls. And a first optical film and a second optical film are bonded to each other, wherein the laminated optical film is a method for manufacturing a laminated optical film, and is the outermost of at least one of the pair of bonding rolls. The outer layer is rubber, and the elastic recovery rate of rubber is 70% or more.

  In this method for producing a laminated optical film, the outermost layer of at least one of the pair of bonding rolls is rubber, and its elastic recovery rate is 70% or more. It is difficult to recover the deformation of the bonding roll. Therefore, according to the manufacturing method of this laminated optical film, it can suppress that the defect based on the damage | wound and deformation | transformation of a bonding roll generate | occur | produces in a laminated optical film.

  Here, at least one of the second optical films may be a transparent film. The transparent film may be a protective film, and the first optical film may be a polarizing film. Furthermore, the polarizing film may contain a polyvinyl alcohol resin.

  In this method for producing a laminated optical film, the polarizing film may have a thickness of 20 μm or less, the protective film may have a thickness of 30 μm or less, and the laminated optical film has a thickness of 100 μm or less. May be. In general, as the thickness of the laminated optical film is smaller, defects based on scratches or deformation of the bonding roll are more likely to occur, and thus each film having the thickness can be said to be suitable for applying the present invention.

  As another aspect of the method for producing the laminated optical film, the first optical film is a polarizing plate including a polarizing film and a protective film, and the first optical film and the second optical film are combined with an adhesive layer. You may paste through.

  Also 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.

  In any of the above production methods, the rubber hardness measured according to JIS K 6253 may be 83 to 97 °. Even with this rubber hardness, if the elastic recovery rate satisfies the above value, the effect of the present invention is exhibited.

  In any of the above production methods, the pair of bonding rolls may be such that the outermost layer may be rubber, and the elastic recovery rate of rubber may be 70% or more. In this case, the effect of the present invention is further improved.

  In any of the above production methods, at least one pressing roll is brought into contact with at least one bonding roll of the pair of bonding rolls, and the bonding roll is pressed in a direction in which the pair of bonding rolls approach each other. May be. In this case, since it becomes easy to apply a uniform load in the width direction of the bonding roll, it is preferable.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the laminated optical film which can suppress that the defect based on the damage | wound of a bonding roll and a deformation | transformation generate | occur | produces in a laminated optical film can be provided.

It is a figure which shows a mode that each film is bonded by a pair of bonding roll. It is sectional drawing of the polarizing plate which concerns on 1st Embodiment. It is explanatory drawing of how to obtain | require an elastic recovery factor. (A) is sectional drawing of the polarizing plate with an adhesive concerning 2nd Embodiment. (B) is sectional drawing of the other polarizing plate with an adhesive which concerns on 2nd Embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same part or an equivalent part, and the overlapping description is abbreviate | omitted. The dimensional ratios in the drawings do not necessarily match the actual ones, and in particular, the thickness is exaggerated.

<First Embodiment>
As 1st Embodiment, the polarizing film as a 1st optical film and the protective film as a 2nd optical film are bonded together, and the example which manufactures the polarizing plate as a laminated optical film is shown.

  As shown in FIG. 1, between a pair of rotating laminating rolls 1 and 1, a polarizing film 2 and protective films 3 and 3 arranged on both sides thereof are introduced while being conveyed, and both films Is formed.

  Here, immediately 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 (FIG. 2) between the polarizing film 2 and the protective films 3, 3. See). As a method of interposing the adhesive layer 5, a mode in which an adhesive is applied to both surfaces of the polarizing film 2 may be used, or a mode in which an adhesive is applied to the surface facing the polarizing film 2 among the surfaces of the protective films 3 and 3. But you can. The polarizing film 2 and the protective films 3 and 3 are bonded by the adhesive.

  At the time of bonding, the pair of bonding rolls 1, 1 may be pressed by a pair of pressing rolls 6, 6 provided so as to be in contact therewith. Here, the pair of pressing rolls 6 and 6 are provided on the straight line connecting the pair of bonding rolls 1 and 1 and sandwiching the bonding rolls 1 and 1. And the press rolls 6 and 6 press the bonding rolls 1 and 1 in the direction which approaches mutually. It is preferable to use the pressing rolls 6 and 6 because it is easy to apply a uniform load in the width direction of the bonding rolls 1 and 1. In addition, a press roll does not necessarily need to be made into a pair, It is good also as an aspect which presses one bonding roll with one press roll.

  The bonding rolls 1 and 1 and the pressing rolls 6 and 6 are all rotatable. By rotating at least one of the bonding rolls 1 and 1 and the pressing rolls 6 and 6, the bonding rolls 1 and 1 rotate, and the polarizing film 2 and the protective films 3 and 3 are bonded and conveyed. Can do. The roll that is not rotationally rotated rotates in association with the rotational driving of the contacting roll.

  The laminated film 4 after passing through the pair of bonding rolls 1, 1 is such that the polarizing film 2 and the protective films 3, 3 are bonded by the adhesive layers 5, 5. Then, the laminated film 4 is completed as the polarizing plate (laminated optical film) 10 shown in FIG. 2 by curing the adhesive layer 5.

  The polarizing plate 10 has a protective film 3 laminated on both surfaces of a polarizing film 2 with an adhesive layer 5 interposed therebetween.

  As the material of the polarizing film 2, known materials that have been conventionally used for the production of polarizing plates can be used. For example, polyvinyl alcohol resin, polyvinyl acetate resin, ethylene / vinyl acetate (EVA) resin, polyamide Examples thereof include resins and polyester resins. Of these, polyvinyl alcohol resins are preferred. Usually, as a starting material for producing the polarizing film 2, 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 is used. The polarizing film 2 is obtained by subjecting this unstretched film to dyeing treatment, boric acid treatment, and stretching treatment.

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

  The protective film 3 is a film that prevents the main surface and end of the polarizing film 2 from cracking and scratching. Here, the “protective film” refers to a film physically laminated at a position closest to the polarizing film 2 among various films that can be laminated on the polarizing film 2.

  The protective film 3 is preferably composed of various transparent resin films known in the field of polarizing plates. For example, cellulose resin whose typical example is triacetyl cellulose, polyolefin resin whose typical example is polypropylene resin, cyclic olefin resin whose typical example is norbornene resin, acrylic whose typical example is polymethyl methacrylate resin Examples thereof include polyester resins and polyester resins having polyethylene terephthalate resins as representative examples. Among these, cellulose resin is representative.

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

  The protective films 3 and 3 may be made of the same material as each other or may be made 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, and still more preferably 9 to 25 μm.

  As the adhesive, various adhesives conventionally used in the production of polarizing plates can be used. For example, an epoxy resin that does not contain an aromatic ring in the molecule is preferable from the viewpoint of weather resistance, refractive index, cationic polymerizability, and the like. Moreover, what hardens | cures by irradiation of active energy ray (an ultraviolet ray or a heat ray) is preferable.

  As an epoxy resin, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. are preferable, for example. For epoxy resins, polymerization initiators (for example, photocationic polymerization initiators for polymerization by UV irradiation, thermal cationic polymerization initiators for polymerization by heat ray irradiation), and other additives (sensitizers, etc.) Can be added to prepare an epoxy resin composition for coating.

  As the adhesive, acrylic resins such as acrylamide, acrylate, urethane acrylate, and epoxy acrylate, and 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 cell (image display element) such as a liquid crystal cell. The polarizing plate 10 can further include another optical layer laminated on the protective film 3. As another optical layer, a reflective polarizing film that transmits a certain kind of polarized light and reflects polarized light having the opposite properties; a film with an antiglare function having an uneven surface; a film with a surface antireflection function; surface A reflective film having a reflective function; a transflective film having both a reflective function and a transmissive function; and a viewing angle compensation film.

  The thickness of the polarizing plate 10 comprising 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 further preferably 30 to 80 μm. preferable.

  As for a pair of bonding rolls 1 and 1, as for all, the outermost layer consists of rubber | gum. The whole of the bonding rolls 1 and 1 may be made of rubber, or the center part may be made of metal and only the outermost layer may be made of rubber. Moreover, as another aspect, the outermost layer of one bonding roll 1 may consist of rubber | gum, and the outermost layer of the other bonding roll 1 may consist of metal. That is, at least one outermost layer of the pair of bonding rolls 1 and 1 only needs to be made of rubber.

  The roll diameter of the bonding rolls 1 and 1 is preferably 50 to 500 mm, more preferably 80 to 450 mm, and 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 linear pressure to each film at the time of 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, still 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 roll is strong, and wrinkles and the like are likely to occur on the film during bonding. On the other hand, when the rubber layer is too thick, the linear pressure on each film laminated at the time of bonding becomes insufficient, and defects such as bubbles may occur in the laminated film 4. On the other hand, if the rubber layer is too thick, it takes a lot of time to manufacture the rubber roll, which is not preferable from an economical viewpoint. The rubber layer may be formed by laminating a plurality of materials having different compositions from the viewpoint of adhesion to the metal roll.

  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 that has occurred is easy to recover, the elastic recovery rate is preferably 75% or more, more preferably 80% or more, and 85% or more. More preferably. Examples of the upper limit of the elastic recovery rate include 99%, 97%, and 95%.

  Here, the “elastic recovery rate” is the ratio of the elastic deformation to the total amount of work based on both deformations when the indentation work is given to a member exhibiting plastic deformation and elastic deformation. Say.

  The elastic recovery rate can be measured using a micro hardness meter (for example, product name “Fischer Scope HM2000”, manufactured by Fisher Instruments Co., Ltd.). That is, a regular square pyramid Vickers indenter (made of diamond, facing angle 136 °) is pushed from the surface at a load speed of 350 mN / 10 s against the test object, reaches a maximum load of 350 mN, and then holds the maximum load for 10 s. Then, it can be determined from the test load and the indentation depth when the Vickers indenter is removed from the surface to be tested at an unloading speed of 350 mN / 10 s.

Specifically, when the relationship between the indentation depth (h) when the Vickers indenter is indented into the test object and the magnitude of the observed test load (F) is shown in a graph, as shown in FIG. Become. Here, h on the horizontal axis indicates the length of the portion of the height of the Vickers indenter that has been pushed into the test object. When the Vickers indenter is pushed in from the measurement start point t ₀ through t ₁ to t ₂ , and then the pushing is released, t ₃ is reached. indentation depth h _p of the t ₃ point, it relaxed from t ₂ point becomes smaller than the indentation depth h _c that is expected if was linear. Here, the region surrounded by the points t _{0 to} t _{3 is} the amount of work of plastic deformation (W _plast ), and the t ₂ -t ₃ line generated when the pressing is released and t ₂ The region surrounded by the h _max line parallel to the vertical axis and the horizontal axis is the work of elastic deformation (W _elast ).

Here, the elastic recovery rate is
Elastic recovery _{(%) = {W elast /} (W elast + W plast)} × 100
It is a value defined by.

  Examples of the rubber material of the outermost layer of the bonding roll 1 include NBR (acrylonitrile butadiene rubber), urethane rubber, silicon rubber, EPDM rubber, butyl rubber, and fluorine rubber.

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

  The material of the pressing rolls 6 and 6 may be metal or rubber. In the case of rubber, preferred values for the elastic recovery rate and rubber hardness are the same numerical ranges as the elastic recovery rate and rubber hardness of the rubber in the bonding roll 1.

  Although the preferable conditions of the pressure concerning the film pinched | interposed with the bonding rolls 1 and 1 at the time of bonding are not specifically limited, 0.01-10 MPa is preferable and 0.1-5 MPa is more preferable. When the said pressure is large, it exists in the tendency for the defect based on the damage | wound and deformation | transformation of the bonding rolls 1 and 1 to generate | occur | produce easily. Moreover, when the said pressure is small, it will not bond uniformly and it exists in the tendency for defects, such as a bubble, to generate | occur | produce easily.

  Preferable conditions for the tension applied to each film at the time of bonding may vary depending on the film material, the bonding temperature, etc., but the film before bonding is preferably 10 to 1000 N / m, more preferably 50 to 500 N / m. preferable. Moreover, 10-2000 N / m is preferable and, as for the tension | tensile_strength applied to the film after bonding, 100-1500 N / m is more preferable. When the tension is in the above range, wrinkles and sagging are less likely to occur in the film, and the possibility that the film is stretched or broken can be further reduced.

  In the manufacturing method of the polarizing plate 10 demonstrated above, since the outermost layer of a pair of bonding rolls 1 and 1 is rubber | gum, and the elastic recovery rate is 70% or more, the bonding rolls 1 and 1 are scratched. Deformation hardly occurs. Moreover, even if the bonding rolls 1 and 1 are damaged or deformed, they are difficult to transfer to the polarizing plate 10. Therefore, according to the manufacturing method of this polarizing plate 10, it can suppress that the defect based on the damage | wound and deformation | transformation of the bonding rolls 1 and 1 generate | occur | produces in the polarizing plate 10. FIG.

  In particular, the smaller the thickness of the film to be bonded or the polarizing plate to be manufactured, the easier it is to generate defects based on scratches and deformation of the bonding roll, so this manufacturing method is suitable for bonding a film having a small thickness. It can be said that. Moreover, it becomes easy to control appearances, such as a skin defect and a stripe, favorably by making elastic recovery rate and rubber hardness into said value in bonding of a film with small thickness.

  In addition, in the said embodiment, although the example (three sheet bonding) which bonds the protective films 3 and 3 to both surfaces of the polarizing film 2 was shown, the aspect (2) which bonds the protective film 3 only to the single side | surface of the polarizing film 2. It is good also as sheet bonding).

  In the above embodiment, the example in which the first optical film is the polarizing film 2 and the second optical film is the protective films 3 and 3 has been described, but these may be other types of films. . Moreover, the film bonded on both surfaces of the polarizing film 2 does not necessarily need to be the same kind of film, and may be a different kind of film.

<Second Embodiment>
As 2nd Embodiment, the polarizing plate as a 1st optical film and the other optical film as a 2nd optical film are bonded, and the "polarizing plate with an adhesive" as a laminated optical film is manufactured. An example is shown. 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 production method of the present embodiment has an adhesive layer 7 on one side of the polarizing plate 10 produced in the first embodiment. The temporary protective film (second optical film) 8 is bonded.

  The temporary protective film 8 is a film that can be peeled off from the polarizing plate 10 on which the temporary protective film 8 is laminated, and is a film for protecting the surface of the protective film 3 on which the temporary protective film 8 is laminated from damage, abrasion, and the like. is there. The material of the temporary protective film 8 is preferably a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, or polybutylene terephthalate, and the same material as the protective film 3 may be used. Other plastics films having the required strength and optical suitability, such as polyolefin films, polyacetate films, polycarbonate films, polyphenylene sulfide films, polyamide films, polyvinyl chloride films, ethylene-acetic acid A vinyl copolymer film, various liquid crystal polymer films, etc. can be used.

  The temporary protective film 8 is laminated on the protective film 3 and then bonded to the protective film 3 until the use of the polarizing plate 20A with an adhesive, and is peeled off from the protective film 3 at the time of use. At this time, the pressure-sensitive adhesive layer 7 is peeled off from the polarizing plate 10 side while 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 still more preferably 15 to 50 μm.

  The pressure-sensitive adhesive layer 7 can be composed of acrylic resin, silicone resin, polyester, polyurethane, polyether, or the like.

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

  Examples of the method of providing the pressure-sensitive adhesive layer 7 include various pressure-sensitive adhesives such as an acrylic one-component or two-component adhesive, a rubber-based adhesive, and a silicone-based adhesive on the temporary protective film 8. After the pressure-sensitive adhesive layer 7 is formed, a method of laminating it on the protective film 3 may be used. Usually, a film that is once wound up in a roll shape with a release film coated on the pressure-sensitive adhesive layer is bonded (two sheets). The release film is peeled off immediately before bonding). Moreover, the method of apply | coating the solution containing the said resin and arbitrary additive components to the protective film 3 of the polarizing plate 10 may be used. After providing the pressure-sensitive adhesive layer 7, the polarizing plate 10 and the temporary protective film 8 are bonded with a pair of bonding rolls shown in FIG. .

  Also in this embodiment, it can suppress that the defect based on the damage | wound and deformation | transformation of the bonding rolls 1 and 1 generate | occur | produces in the polarizing plate 20A with an adhesive.

  Although the example in which the second optical film is the temporary protective film 8 is shown above, the second optical film is a separate film 9 instead of the temporary protective film 8 as shown in FIG. There may be.

  The separate film 9 is a peelable film that is attached for the purpose of protecting the pressure-sensitive adhesive layer 7 and preventing adhesion of foreign matter, and is peeled off when the pressure-sensitive adhesive polarizing plate 20B is used so that the pressure-sensitive adhesive layer 7 is exposed. Is done. The separate film 9 can be made of, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate, or the like. Among these, a stretched film of polyethylene terephthalate is preferable.

  The pressure-sensitive adhesive layer 7 on which the separate film 9 is laminated is a layer that functions when the polarizing plate 10 is attached to another article (for example, a liquid crystal cell or a touch panel). As the material for the pressure-sensitive adhesive layer 7, the same material as that used when the temporary protective film 8 is laminated can be used.

  The separation film 9 may be subjected to a release treatment with a silicone resin or the like on the surface in contact with the pressure-sensitive adhesive layer 7 so that it can be easily peeled off when the pressure-sensitive adhesive polarizing plate 20B is used. When the separate film 9 is peeled off, the pressure-sensitive adhesive layer 7 remains on the polarizing plate 10 side.

  The thickness of the separate film 9 is preferably 5 to 70 μm, more preferably 10 to 60 μm, and still more preferably 15 to 50 μm.

  In the present embodiment, an example of the polarizing plates 20A and 20B with the adhesive in which the polarizing plate 10 further includes the temporary protective film 8 or the separate film 9 is shown, but the polarizing plates 20A and 20B with the adhesive are temporarily protected. Both the film 8 and the separate film 9 may be provided.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the first optical film is a polarizing film, but other optical films having no polarizing property can also be targeted.

  Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the following Example.

The films used are 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 then dried. Thickness 12 μm.
Protective film A: Triacetyl cellulose film (trade name “Konica Minolta Optical Film KC2UAW”, manufactured by Konica Minolta Advanced Layer Co., Ltd.). Thickness 25 μm.
Protective film B: Cyclic olefin resin film (trade name “ZEONOR FILM ZF14-23”, manufactured by ZEON CORPORATION). Thickness 23 μm.
-Temporary protective film with adhesive: a film comprising a polyethylene terephthalate base film and an acrylic resin adhesive layer (trade name "AS3-304 (19)", manufactured by Fujimori Kogyo Co., Ltd.). A thickness of 58 μm (a thickness of only the base film excluding the pressure-sensitive adhesive layer is 38 μm).
Separate film with adhesive: A film (trade name “# L2-NCF”, manufactured by Lintec Corporation) made of a polyethylene terephthalate separate film that has been subjected to a release treatment and an acrylic resin adhesive. Thickness 43 μm (thickness 38 μm of separate film excluding adhesive layer).

  The adhesive was prepared as follows. In 100 parts by weight of water, 4 parts by weight of acetoacetyl group-modified polyvinyl alcohol (trade name “Gosefimer Z-200”, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and sodium glyoxylate (trade name “SPM-01”) 4 parts by weight (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was dissolved to prepare an aqueous adhesive.

The rubber material used for the bonding roll and the pressure roll was produced by the following method.
NBR polymer, sulfur, silicon dioxide, and phthalic acid plasticizer were weighed so as to have a predetermined weight ratio, kneaded with a kneader, and then molded into a roll by sheet molding. The composition of the produced rubber material was the following weight ratio.
・ Rubber material A
N B R polymer: Sulfur: silicon dioxide: phthalate plasticizer = 100: 12: 60: 9
・ Rubber material B
N B R polymer: Sulfur: silicon dioxide: phthalate plasticizer = 100: 7: 60: 8
・ Rubber material C
N B R polymer: Sulfur: silicon dioxide: phthalate plasticizer = 100: 8: 70: 3
Table 1 shows the elastic recovery rate (%) and hardness (°) of the produced rubber material.

The rolls used are as follows.
Bonding roll whose outermost layer is made of rubber: The entire roll diameter is 300 mm, and the thickness of the rubber material in the outermost layer is 16.5 mm. The rubber materials A, B, and C were used as the rubber material.
・ Metal roll: Made of stainless steel.
・ Pressing roll: The rubber material is the above rubber material A.

(Examples 1 and 2)
Using the bonding roll shown in Table 1, the protective film A was bonded to one surface of the polarizing film, and the protective film B was bonded to the other surface (three sheets bonded) to obtain a polarizing plate. At this time, the adhesive was applied to the polarizing film side. The thickness of the obtained polarizing plate was 60 μm.

(Example 3)
Using the bonding roll shown in Table 1, the polarizing plate produced in Example 1 and the temporary protective film with an adhesive were bonded (two sheets bonding), and the polarizing plate with an adhesive was obtained.

Example 4
Using the bonding roll shown in Table 1, the polarizing plate produced in Example 1 and the adhesive-attached separate film were bonded (two-sheet bonding) to obtain a pressure-sensitive adhesive polarizing plate.

(Example 5)
Using the bonding roll shown in Table 1, the protective film A was bonded to one surface of the polarizing film, and the protective film B was bonded to the other surface (three sheets bonded) to obtain a polarizing plate. At this time, the adhesive was applied to the polarizing film side. Moreover, the metal roll was pressed against the rubber roll side using the press roll. The thickness of the obtained polarizing plate was 60 μm.

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

The surfaces of the polarizing plates and the polarizing plates with adhesives obtained in Examples 1 to 5 and Comparative Example 1 were visually observed. The results were as shown in Table 1.
Evaluation symbol A: No defects were found.
B: A slight defect that was considered to have been transferred from the scratch or deformation of the bonding roll was observed (within an allowable range).
C: Many defects considered to have been transferred from the scratch or deformation of the bonding roll were observed.

  DESCRIPTION OF SYMBOLS 1 ... Bonding roll, 2 ... Polarizing film (1st optical film), 3 ... Protective film (2nd optical film), 4 ... Laminated film, 5 ... Adhesive layer, 6 ... Press roll, 7 ... Adhesive Layer, 8 ... temporary protective film (second optical film), 9 ... separate film (second optical film), 10 ... polarizing plate (laminated optical film, first optical film), 20A, 20B ... adhesive A polarizing plate (laminated optical film).

Claims (9)

Between a pair of rotating laminating rolls, a first optical film, a second optical film disposed on one or both sides of the first optical film via an adhesive layer or an adhesive layer, Is a method for producing a laminated optical film, wherein the first optical film and the second optical film are bonded together,
Of the pair of bonding rolls, the outermost layer of at least one of the bonding rolls is rubber,
Ri der at least 70% elastic recovery of the rubber,
Rubber hardness of the rubber was measured in accordance with JIS K 6253 is, Ru eighty-three to ninety-seven ° der method for producing a laminated optical film.   The method for producing a laminated optical film according to claim 1, wherein at least one of the second optical films is a transparent film. The transparent film is a protective film,
The method for producing a laminated optical film according to claim 2, wherein the first optical film is a polarizing film.   The said polarizing film is a manufacturing method of the laminated optical film of Claim 3 containing polyvinyl alcohol-type resin. The polarizing film has a thickness of 20 μm or less,
The protective film has a thickness of 30 μm or less,
The manufacturing method of the laminated optical film of Claim 3 or 4 whose thickness of the said laminated optical film is 100 micrometers or less. The first optical film is a polarizing plate comprising a polarizing film and a protective film,
The manufacturing method of the laminated optical film of Claim 2 which bonds a said 1st optical film and a said 2nd optical film through the said adhesive layer. The polarizing film has a thickness of 20 μm or less,
The protective film has a thickness of 30 μm or less,
The manufacturing method of the laminated optical film of Claim 6 whose thickness of the said polarizing plate is 100 micrometers or less. Each of the pair of bonding rolls has an outermost layer of rubber,
The method for producing a laminated optical film according to any one of claims 1 to 7 , wherein an elastic recovery rate of the rubber is 70% or more. The at least 1 press roll is made to contact at least one said bonding roll among said pair of bonding rolls, and the said bonding roll is pressed in the direction where the said pair of bonding rolls mutually approach. The method for producing a laminated optical film according to claim 8 .

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