JPH1110797A - Lamination process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lamination process for obtaining an (optical) laminate of a cellulose film and a polyvinyl alcohol film, both of which are free from a microbubble defect and have a presentable appearance. SOLUTION: When a cellulose film and a polyvinyl alcohol film are laminated to each other with an adhesive, formulas 3>=X-Y>=0.01 and 10>=Y>=0.1 are to be satisfied. In the formulas, X is the supply amount (g) of an adhesive; Y is the actual consumption (g) of the adhesive; and X-Y is the leakage amount (g) of the adhesive at both ends at the time of adhesion and these parameters indicate the amount of the adhesive per 1 m<2> of laminated face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laminating a cellulose film and a polyvinyl alcohol film, and more particularly, to an optical laminate such as a polarizing plate or a retardation plate having a small appearance defect and good appearance quality. And a lamination method particularly useful in the production of

[0002]

2. Description of the Related Art Conventionally, a polyvinyl alcohol (hereinafter sometimes referred to as PVA) -based polarizing plate or retardation plate has a structure in which a cellulose film is provided on both sides of a polarizing film or a retardation film. When manufacturing such a polarizing plate or a retardation plate, wet lamination using an adhesive (aqueous adhesive) is usually performed. Specifically, the adhesive is first applied to a polarizing film (or a retardation film). Film on both sides of the film to remove cellulose triacetate (hereinafter TAC)
It may be called. ) A method of repeating lamination with a film one side at a time, applying an adhesive on both sides of a polarizing film (or retardation film) first,
A method of laminating with a C film, a method in which an adhesive is first applied to one side of each TAC film and the lamination with a polarizing film (or a retardation film) is repeated one side at a time, and the adhesive is first applied to one side of each TAC film. On both sides at the same time polarizing film (or retardation film)
Laminating with the adhesive, first apply the adhesive to one TA
Coat one side of the C film and laminate it with a polarizing film (or retardation film) to obtain a two-layer laminate, and further apply an adhesive to the polarizing film (or retardation film) side of the two-layer laminate. Laminating with a TAC film, a glue is first applied to one side of a polarizing film (or a retardation film), and then laminated with one TAC film to obtain a two-layer laminate, and then the other TA
A method of applying an adhesive to one side of the C film and laminating the TAC film and the two-layer laminate, and a method of applying and laminating the adhesive simultaneously with the polarizing film (or retardation film) and the TAC film in three layers ( Squeeze coat and lamination). In such a laminating method, the adhesive to be used does not generate excessive foaming, does not damage the base material to be laminated, and a foreign matter such as a residual adhesive remaining on the laminating roll. Use a roll that is easy to remove even if it adheres, and use a roll that does not extremely generate static electricity during use.There is no special point to note in the conventional technique at the time of lamination, and lamination It was an easy technique at the time of difficulty.

On the other hand, the progress of liquid crystal display devices using such a polarizing plate or a retardation plate has been remarkable in recent years. In the past, only TN type liquid crystal display devices such as small watches were used. The STN type liquid crystal display device and the TFT type liquid crystal display device represented by the car navigation system were invented and actually used. In particular, the progress of the TFT type liquid crystal display device has been remarkable, and the large display and the display quality can be realized as CRT display device. Have been.

Accordingly, it is required that various performances of various parts such as a glass cell, a liquid crystal material, a polarizing plate, and a retardation plate in a liquid crystal display device are improved, and that defects in them are further reduced and the number thereof is reduced. It has become. The polarizing plate, which used to be only an 8-segment monochrome display, has been implemented in notebook PCs and car navigation systems, leading to more detailed and precise color moving image display, optical performance, durability, visibility, appearance quality, and large area. Various improvements in performance such as reduction in optical performance and unevenness in optical performance have been required. At the polarizing plate manufacturing site, when manufacturing TN type polarizing plates such as small watches in the past, defects
The size is 100-700 μm, and the number is 5-35 / m
Those had been at ^2, when the current TFT type polarizing plate production is required to be free from defects (that is, a 0 / m ^2), in reality, one / m ² or less in 60~100μm In the era of the requirement of 0.05 pieces / m ² , innovation in the manufacturing method has been rapidly demanded.

[0005]

SUMMARY OF THE INVENTION In view of the above background, the present invention is particularly preferable for a polarizing plate and a retardation plate for a TFT type liquid crystal display device (referred to collectively as an optical laminate) and has a fine structure. Bubble defects (fine bubble defects remaining in the adhesive between the cellulose-based film and the polyvinyl alcohol-based film, having a size of 50 to 1500 μm. It is an object to provide a method of laminating a cellulose-based film and a polyvinyl alcohol-based film with few nuclei and only foamed cells.)

[0006]

Means for Solving the Problems However, as a result of intensive studies to solve such problems, the present inventor has found that when laminating a cellulose-based film and a polyvinyl alcohol-based film using an adhesive, the following (1) ),
When a laminating method satisfying the expression (2) is performed, it has been found that a laminated body having no fine bubble defects can be obtained, and the present invention has been completed. 3 ≧ X−Y ≧ 0.01 (1) 10 ≧ Y ≧ 0.1 (2) (where X is the adhesive supply amount (g) and Y is the actual adhesive) (Amount used (g), XY is the amount of liquid leakage (g) at both ends at the time of bonding, and indicates the amount per 1 m ^{2 of the} laminated surface.)

Further, the effect of the present invention can be obtained when the two ends of the laminating roll are disposed at the same position as the two ends of the polyvinyl alcohol-based film or outside the both ends and inside the both ends of the cellulose-based film. It turned out to be able to demonstrate it. In the present invention,
A film in which polarization properties are imparted to a PVA film by the adsorption orientation of an iodine compound is referred to as a "polarizing film", and when a TAC film as a protective film is provided on both sides (or one side) of the "polarizing film", the "polarizing plate" It is called and distinguished. Further, a film to which a PVA film is stretched to have retardation performance is referred to as a “retardation film”, and both sides (or one side) of the “retardation film” are TA films of a protective film.
When a C film is provided, it is distinguished by being referred to as a “retardation plate”.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. The substrate used in the lamination method of the present invention will be described. The cellulose ester as a raw material of the cellulose-based film used in the present invention is not particularly limited as long as it is an ester of cellulose and an acid, preferably, an ester of cellulose and a fatty acid, cellulose triacetate, cellulose diacetate, cellulose Tripropionate, cellulose dipropionate and the like are used.
As a raw material of such a cellulosic film for use as an optical laminate, cellulose triacetate (cellulose triacetate) is preferable in terms of low birefringence and high transmittance, and the thickness of the cellulosic film is particularly limited. However, the thickness is preferably 20 to 150 μm, more preferably 50 to 85 μm.
μm is preferred. In addition, these cellulose-based films are usually put to practical use after their adhesive surfaces are surface-modified such as alkali saponification or corona treatment in order to reinforce adhesion in lamination.

The raw material (polyvinyl alcohol-based resin) of the polyvinyl alcohol-based film used in the present invention is:
Usually, it is produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. However, the present invention is not limited to this, and a small amount of unsaturated carboxylic acid (salt, ester, amide, nitrile, etc. ), Olefins, vinyl ethers, unsaturated sulfonic acid salts, and the like. The polyvinyl alcohol-based film is not particularly limited as long as such a raw material is used, but a polarizing film obtained by treating an iodine compound and a boron compound after forming a polyvinyl alcohol-based resin, or a polyvinyl alcohol-based resin is formed. And then at 130-230 ° C at 1.01-1.4.
There is a retardation film obtained by a 5-fold stretching treatment, and further, a polarizing film having a high degree of polarization and high transmittance and a retardation film having a low retardation (3 to 50 nm) suitable for a TFT type liquid crystal display device are preferable. . The thickness of the polyvinyl alcohol-based film is not particularly limited, but is preferably 20 to 150 μm, and more preferably 45 to 85 μm.
μm is preferred.

[0010] The adhesive used in the present invention means a solvent and an additive unless otherwise specified. The amount of X and Y is not limited to the solid content in the adhesive but also to the solvent. Is the weight at the time of coating, including The resin for the adhesive is not particularly limited as long as the cellulose-based film and the polyvinyl alcohol-based film can be adhered to each other and are transparent after drying. For example, a polyvinyl acetate-based resin, a polyvinyl alcohol-based resin, There are ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer saponified resin, epoxy resin, acrylic resin, urethane resin, etc., but in terms of transmittance, water-based adhesive mainly containing polyvinyl alcohol-based resin. Resins are preferred, and among them, the degree of saponification is 90.0 to 100 mol%, and the degree of polymerization is 1500 to 100.
00 polyvinyl alcohol resin is particularly preferred.

The water-based adhesive may or may not contain additives, and is not particularly limited. However, dialkyl sulfosuccinate metal salts, fatty acid alkylol amide sulfates, secondary alcohols, etc. At least one selected from ethoxy sulfate, N-acylmethyltaurine, α-olefin sulfonate, and sodium formalin naphthalene sulfonate condensate, and the content is 0.05 to 1.5% by weight. When the content is less than 0.05% by weight, the suppressive force against foaming tends to decrease, and 1.5% by weight
When the value exceeds, the tendency of the interface peeling between the cellulose film and the polyvinyl alcohol film during the durability test increases, which is inconvenient. Among such additives, a metal salt of a dialkyl sulfosuccinate, particularly a soda salt of a dialkyl sulfosuccinate, is optimal because the effect is exhibited with a small amount of addition. The industrial production method of such a water-based adhesive is not particularly limited, but after dissolving a polyvinyl alcohol-based resin and the above-mentioned additives in water, the water-based adhesive is filtered and put to practical use. The water for the solvent is not particularly limited, and the filtration is not particularly limited.
% Filtration capacity)
When the effect of the present invention can be maximized, and when the thickness exceeds 0.3 μm, it is inconvenient that minute foreign matters which cause the generation of fine bubble defects cannot be removed from the aqueous adhesive used for lamination. In addition, usually, it is used for lamination after being filtered with a 0.1-0.3 μm membrane filter.

Next, a method for laminating a cellulose film and a polyvinyl alcohol film will be described. In the present invention, the greatest feature of laminating such a cellulose-based film and a polyvinyl alcohol-based film using an adhesive is to satisfy the following expressions (1) and (2). 3 ≧ X−Y ≧ 0.01 (1) 10 ≧ Y ≧ 0.1 (2) (where X is the adhesive supply amount (g) and Y is the actual adhesive) (Amount used (g), XY is the amount of liquid leakage (g) at both ends at the time of bonding, and indicates the amount per 1 m ^{2 of the} laminated surface.)

In this connection, when XY exceeds 3, the vicinity of the laminating roll is contaminated with the leakage adhesive or the flow of the adhesive (at the time of lamination) at the time of lamination becomes too strong, and the number of fine bubbles increases. When XY is less than 0.01, the occurrence of microbubble defects on the adhesive surface between the cellulose film and the polyvinyl alcohol film increases, or the cellulose film or the polyvinyl alcohol film It is not possible to remove film-containing components such as a plasticizer and a lubricant eluted from the surface of the adhesive into the adhesive, and these are inconvenient because they become the core and bubbles are generated.
When Y exceeds 10, the amount of the adhesive is too large, and large irregularities (size: 500 to 5000 μm) and large bubble defects (size: 300 to 5000 μm) are generated.
When the amount is less than the above, the amount of the adhesive is too small to cause poor adhesion, that is, large bubbles are generated between the cellulose-based film and the polyvinyl alcohol-based film, which is inconvenient.

Factors controlling the amounts of X-Y and Y of the adhesive include the type of adhesive used, the concentration and viscosity of the adhesive, the type of coating coater used, and the liquid supply to the coating coater. Coating coater conditions such as amount and liquid supply conditions,
The hardness and roughness of the rubber and resin on the surface of the laminating roll, the combination of the laminating rolls, the roll clearance between the laminating rolls, the shape and surface width of the laminating rolls, the nip pressure of the laminating, the laminating speed, and the water content of the film to be laminated There are various laminating conditions such as a surface energy state of a film surface, a concentration, a viscosity, and a thickness of a coated adhesive, a means for extruding the adhesive from a laminating roll, and the like, and the amounts of XY and Y are controlled. The method may be carried out in any combination of these factors, and such a method is not particularly limited. However, after defining X, a method of controlling by defining the amount of Y, and a method of controlling XY There are two methods of controlling by defining the amount. The method of controlling by regulating the amount of Y includes a method of controlling by a roll clearance between laminating rolls, a method of controlling by a concentration of an adhesive, and a method of controlling by a laminating speed. There are many methods such as a method of controlling by nip line pressure, and a method of controlling by defining the amount of XY includes a method of controlling by forcibly sucking the coating liquid from both ends of the laminate. Among them, a method in which the amount of Y is regulated and controlled by the nip line pressure is preferable.

Although the nip line pressure is not particularly limited, it is usually selected from the range of 10 to 1000 kg / m. Regarding the method of controlling the line pressure, usually, two diameters are set at two places at both ends of the laminating roll. Is provided with a shaft having a diameter of 25 to 50 mm, and a pressurizing device using an air cylinder is provided at at least both ends of the laminating roll, so that the linear pressure during lamination can be controlled.

The other laminating conditions used in the control method are not particularly limited. For example, the adhesive supply amount X (g) can be arbitrarily selected and is not particularly limited. .11-13
It is appropriately selected from the range of (g). Laminating speed,
The temperature of the laminating roll, the cellulosic film, the polyvinyl alcohol-based film, and the tension of the laminate after lamination thereof can also be arbitrarily selected, and are not particularly limited, but usually, the speed is in the range of 1 to 15 m / min. Than,
The temperature is in the range of 10 to 35 ° C and the tension is 0.5
It is appropriately selected from the range of 25 kg / 1 m width.

The shape and material of the laminating roll to be used are not particularly limited. Usually, the diameter of the laminating roll is also not particularly limited, but is 75 to 300 mm.
The surface length of the laminating roll is not particularly limited, either, but both ends of the laminating roll are at the same position as the both ends of the polyvinyl alcohol-based film or outside both ends, and inside the both ends of the cellulose-based film. It is particularly preferable that a laminating roll is provided, and when both ends of the laminating roll are at the same position as or outside the both ends of the cellulosic film, fine bubbles cannot be completely removed and are generated near the ear end of the laminate. This is disadvantageous because the number of microbubble defects increases. Further, when both ends of the laminating roll are inside the both ends of the polyvinyl alcohol-based film, irregularities and fine bubble defects are concentrated near the edge of the polyvinyl alcohol-based film, which is inconvenient.

The material of the laminating roll is not particularly limited, but at least one surface material of the laminating roll is made of resin or rubber, and the laminating method includes the following seven methods industrially as described above. ,
In order to carry out such lamination, it is necessary to apply an adhesive prior to the base material to be laminated in the above-mentioned methods.
Also, a coater is used.Specifically, there are a microgravure coater, a mangle roll coater, a die coater, a sponge roll coater, an exaine roll coater and the like which can be applied thinly without damaging the base material to be used and have less foaming. Is done. The method is called squeeze coat and lamination in which the coater and the laminator are performed in the same place, and the method is preferable in terms of suppressing curl generated in the film, in terms of production efficiency and simplicity of equipment. It is a target.

In the above cases, two sheets of the cellulose film and the polyvinyl alcohol film are sandwiched between the laminate rolls, and both ends of the laminate roll are installed as described above, and the adhesive (adhesive supply amount X (g)) At the same time as or after coating, the adhesive leaking from the left and right ends of the polyvinyl alcohol-based film (the amount of liquid leaked at both ends during bonding XY)
g) may be removed by suction or the like, and such a removal operation is not particularly limited, but a pipe or the like may be applied to the left end and the right end of the polyvinyl alcohol-based film, and the left end and the right end of the laminate roll to remove the leakage adhesive. A suction method is preferred. In the above case (when three films are used), the width of the front and back two cellulosic films is almost the same, the left end and the right end are almost aligned, and both ends of the laminating roll are installed as described above. At the same time or after the application of the adhesive (adhesive supply liquid amount Xg / per side), the adhesive leaks from both ends of the laminating roll or both ends of the polyvinyl alcohol-based film (the amount of liquid leaked at both ends during bonding X-Yg). (One side) may be removed by suction or the like. Such a removal operation is not particularly limited, but a pipe or the like may be inserted into the left and right ends of the polyvinyl alcohol-based film at a position after the lamination. The method of laminating by leaking the adhesive and applying it is ~
Is the most efficient and preferred.

In the laminating method, usually, two laminating rolls are used as one set in laminating. However, a laminating method using one laminating roll, that is, a laminating roll is arranged on one side and the other side is used. An air slit or an air knife is placed in between, and a cellulose-based film / polyvinyl alcohol-based film or a cellulose-based film / polyvinyl alcohol-based film / cellulose-based film is passed through, and the air slit or air is added while attaching each film to a laminating roll. When using the method of laminating by pressing with compressed air from a knife, if the above laminating method or the above laminating roll is used, the effect of suppressing the occurrence of microbubble defects does not change, but disturbing the nearby air From one laminating roll Preferably more ways to the lamination method 2 using the laminate roll from.

Such a laminate is usually prepared at a temperature of 15 to 2
5 ° C, humidity 50-70% RH, cleanliness 10,000-
In an environment of 100 CFT, it is performed while applying ionized air generated from a static eliminator so that static electricity is not generated on the film, thus forming an optical laminate of a polarizing plate and a retardation plate. 1
After being dried at room temperature at 0 to 35 ° C. for 25 to 285 seconds,
Hot air drying at a temperature exceeding 35 ° C., preferably 40 to 10
It is preferable to dry with hot air at 0 ° C. for 1 to 10 minutes.
When the time is less than 2 seconds, fine bubble defects tend to increase,
When the time exceeds 285 seconds, the durability of the optical laminate of the polarizing plate and the retardation plate is lowered, which is inconvenient. Thus, after such a series of drying steps, an optical laminate having good appearance without fine bubble defects can be obtained.

Although such a lamination method is useful for TAC films, the thickness of one side of these films is 1 to
A TAC film coated with a 10 μm clear hard coat layer or an anti-glare hard coat layer, and furthermore, an ITO layer, an antifouling treatment layer,
It is also useful for laminated TAC films provided with layers imparting various functions such as an antistatic layer and a low reflection layer, and a polarizing plate or a retardation plate free from fine bubble defects can be obtained. T for car navigation and other applications
It is suitable for FT type liquid crystal display devices.

Although the method for laminating an optical laminate such as a polarizing plate or a retardation plate has been described in detail above, the present invention is not limited to these optical laminates, and is not limited to these optical laminates. Regarding the laminate film (laminated body) of polyvinyl alcohol-based film, that is, cellulose film used for film condenser, manga cell screen plate, anti-fog film, anti-glare film, ground glass film, colored film, etc. It is useful when producing a laminate with an alcohol-based film. The present invention has a structure of a cellulose film and a polyvinyl alcohol film, but is also effective for a structure of a laminate of a cellulose film and a cellulose film.

[0024]

Next, the present invention will be described in more detail with reference to examples.
In Examples, “%” is based on weight unless otherwise specified. Example 1 (1) Film and adhesive used for lamination As a polyvinyl alcohol-based film, the average degree of polymerization was 3
A polarizing film having a transmittance of 43.5%, a degree of polarization of 99.95%, a thickness of 20 μm, and a width of 654 mm was prepared using a polyvinyl alcohol-based resin having a base weight of 900 and a saponification degree of 99.5 mol%. A cellulose triacetate film having a thickness of 80 μm and a width of 670 mm and having an adhesive surface alkali-saponified was prepared as a cellulose film. As an adhesive, a polyvinyl alcohol-based resin (polymerization degree 2
600, 99.9 mol% of saponification degree) and 0.5 wt% of dialkyl sulfosuccinate soda salt (“Neocol SW” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were dissolved.
An aqueous adhesive filtered through a 0.1 μm membrane filter was prepared.

(2) Lamination In a clean room having a clean degree of 100 CFT and 25 ° C. and 60% RH, a cellulose triacetate film is placed on both sides of the polarizing film so that the polarizing film enters the center in the width direction of the cellulose triacetate film. While placing, diameter 1
Two rubber rolls obtained by rotating and polishing an NBR rubber roll of 50 mm (rubber thickness 15 mm, core diameter 120 mm, roll surface length 660 mm, core material SS410) and hardness (Shore A) 80 (degrees) with sandpaper # 3000 1
Using a pair, while arranging such two laminating rolls so as to enter the center in the width direction of the cellulose triacetate film, each tension is 10 kg / 1 m width, lamination speed is 5.0 m / min, and linear pressure is applied. Is 300 kg / 1 m width, with no clearance (a situation where the distance between the Lami rolls can be approached to 0 μm in a state where the film is not sandwiched between the Lami rolls), and has three layers (TAC film / adhesive / polarizing film / adhesive / TAC). Film) was simultaneously laminated. Lamination surface 1m for the lamination
^The adhesive supply amount Xg per ² (per surface) is 6 (g)
And pressurized at the above linear pressure while supplying at
(G) was applied in 5 g. Liquid leakage at both ends during bonding XY
(G) is 1 g, which was removed by inserting thin tubes into the left and right ends of the polarizing film at the point where the adhesive after lamination did not dry out. Immediately after such lamination, 2
After drying at room temperature for 5 seconds at 5 ° C, drying was performed at 90 ° C for 3 minutes to obtain a polarizing plate.

The obtained polarizing plate was cut into a total length in the width direction and a length in the longitudinal direction of 1000 mm to obtain a polarizing plate sample for evaluation. The obtained polarizing plate samples were evaluated as follows.・ (Microbubble defects) The number of microbubble defects in the area of the polarizing plate sample (100 pieces) excluding 13 mm from the edge of the polarizing film was confirmed by visual inspection, and the size was checked with a microscope. Was counted. For fine bubble defects,
For any fine bubbles, those even 50μm or more in size is ○ 0.1 pieces / m ² or less distribution, which exceeds 0.1 pieces / m ² (the state of giant bubbles insufficient adhesive ) Was evaluated as x.

Example 2 The laminating conditions in Example 1 were X = 0.6 (g), the linear pressure of the nip pressure was 470 kg / 1 m, and Y = 0.5.
Example 1 except that (g) (XY was 0.1 (g))
In the same manner as in the above, a polarizing plate was obtained. A polarizing plate sample for cut-out evaluation was obtained and evaluated in the same manner as in Example 1.

Comparative Example 1 The laminating conditions in Example 1 were X = 12 (g), the linear pressure of the nip pressure was 150 kg / 1 m width, and Y = 11.
(G) A polarizing plate was obtained in the same manner as in Example 1 except that (XY was 1 (g)). A polarizing plate sample for cut-out evaluation was obtained and evaluated in the same manner as in Example 1.

Comparative Example 2 The laminating conditions of Example 1 were set such that X = 0.10 (g), the linear pressure of the nip pressure was 750 kg / 1 m width, and Y = 0.
A polarizing plate was obtained in the same manner as in Example 1 except that 08 (g) (XY was 0.02 (g)). A polarizing plate sample for cut-out evaluation was obtained and evaluated in the same manner as in Example 1.

Comparative Example 3 The laminating conditions of Example 1 were X = 9 (g), the linear pressure of the nip pressure was 300 kg / 1 m width, and Y = 5 (g).
A polarizing plate was obtained in the same manner as in Example 1 except that (XY was 4 (g)). A polarizing plate sample for cut-out evaluation was obtained and evaluated in the same manner as in Example 1.

Comparative Example 4 The laminating conditions of Example 1 were as follows: X = 5.008 (g);
The linear pressure of the nip pressure is set to 300 kg / 1m width, and Y =
A polarizing plate was obtained in the same manner as in Example 1 except that 5.000 (g) (XY was 0.008 (g)). A polarizing plate sample for cut-out evaluation was obtained and evaluated in the same manner as in Example 1. Table 1 shows the evaluation results of the fine bubble defects of the example and the comparative example.

[0032]

[Table 1]

[0033]

The laminating method of the present invention satisfies the above-mentioned specific relations (1) and (2) when laminating a cellulose film and a polyvinyl alcohol film with an adhesive. Laminates with good appearance performance are obtained without fine bubble defects, especially when the polyvinyl alcohol-based film is an optical laminate such as a polarizing film or a retardation film, and is used for word processing, television, personal computers, car navigation, etc. It is useful for TFT type liquid crystal display devices.

Claims (6)

[Claims] 1. A laminating method for laminating a cellulose film and a polyvinyl alcohol film using an adhesive, wherein the following formulas (1) and (2) are satisfied. 3 ≧ X−Y ≧ 0.01 (1) 10 ≧ Y ≧ 0.1 (2) (where X is the adhesive supply amount (g) and Y is the actual adhesive) (Amount used (g), XY is the amount of liquid leakage (g) at both ends at the time of bonding, and indicates the amount per 1 m ^{2 of the} laminated surface.) 2. Laminating rolls are arranged so that both ends of the laminating roll are located at the same position as the both ends of the polyvinyl alcohol-based film or outside both ends and inside the both ends of the cellulose-based film. The lamination method according to claim 1. 3. The lamination method according to claim 1, wherein the adhesive is a water-based adhesive containing a polyvinyl alcohol-based resin as a main component. 4. An aqueous adhesive comprising a dialkyl sulfosuccinate metal salt, a fatty acid alkylol amide sulfate, a secondary alcohol ethoxy sulfate, and N
-At least one selected from acylmethyltaurine, α-olefin sulfonate and sodium naphthalene sulfonate condensate, and the content thereof is 0.05 to 1.5% by weight. The lamination method according to claim 3. 5. The lamination method according to claim 1, wherein the cellulose-based film is a cellulose triacetate film. 6. The laminating method according to claim 1, wherein the polyvinyl alcohol-based film is a polarizing film or a retardation film.