TWI671202B - Method of manufacturing sheet film - Google Patents

Abstract

The present invention provides a method for manufacturing a sheet-like film, which is a cutting step having a multilayer film having an adhesive layer having n layers (n is an integer of 1 or more) and obtaining a sheet-like film from the multilayer film, wherein the cutting step The method includes a step of cutting the multi-layer film from a first surface of the multi-layer film to a second surface of the multi-layer film, and cutting the multi-layer film; any of the n-layers of the adhesive layer When the adhesive layer is used as a reference adhesive layer, the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film satisfies the following relational expression (1), t / V <1 / ω ₁ (1)

[In the above-mentioned relational expression (1), t represents the thickness (μm) of the multilayer film, and ω ₁ represents the storage elasticity calculated from the measurement value of the dynamic viscoelasticity measurement performed at the frequency sweep of the reference adhesive layer at a temperature of 20 ° C. Frequency (1 / sec) when the modulus is displayed as 3.0 × 10 ⁵ (Pa)].

Description

Manufacturing method of sheet film

The present invention relates to a method for manufacturing a sheet-like film from a multilayer film having an adhesive layer, and also relates to a manufacturing apparatus for the multilayer film and a cutting method for the multilayer film.

Conventionally, as a method of cutting a multilayer film including a polarizing plate or the like, a method of cutting using a cutting blade is known (for example, Japanese Patent Application Laid-Open No. 2015-33727 (Patent Document 1)).

Patent Document 1 discloses that a cutting blade for cutting a multilayer film uses a cutting blade having a surface roughness at a tip end portion of the blade in a specific numerical range to suppress fluff on a cutting surface.

As described in Patent Document 1, when a multilayer film is cut using a cutting blade, fine unevenness in the form of stripes may occur in the vicinity of the cutting portion on the surface of the multilayer film. When cutting multilayer films for mobile devices such as smartphones to make sheet films, the size of the sheet film is small and the displayed text and images are relatively small. The screen can be seen from a short distance, even with slight unevenness. Obvious and easy to cause defects in appearance. The present inventors have conducted studies and found that when a multilayer film has an adhesive layer, such striped fine unevenness is liable to occur. Then further research found that this could be suppressed This method of fine stripe-like unevenness is completed, and the present invention has been completed.

An object of the present invention is to provide a method and apparatus for producing a sheet-like film capable of suppressing generation of fine unevenness in a stripe shape, and a method for cutting a multilayer film.

This invention provides the manufacturing method and manufacturing apparatus of the sheet-like film shown below, and the cutting method of a multilayer film.

[1] A method for manufacturing a sheet-shaped film, comprising a cutting step of cutting a multilayer film having an adhesive layer having n layers (n is an integer of 1 or more) and obtaining a sheet-shaped film from the multilayer film, wherein the cutting step The method includes a step of cutting the multi-layer film from a first surface of the multi-layer film to a second surface of the multi-layer film, and cutting the multi-layer film; any of the n-layers of the adhesive layer When the adhesive layer is used as a reference adhesive layer, the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film satisfies the following relational expression (1).

t / V <1 / ω ₁ (1)

[In the above-mentioned relational expression (1), t represents the thickness (μm) of the multilayer film, and ω ₁ represents the storage elasticity calculated from the measurement value of the dynamic viscoelasticity measurement performed at the frequency sweep of the reference adhesive layer at a temperature of 20 ° C. Frequency when the modulus is 3.0 × 10 ⁵ (Pa) (1 / s)

[2] The method for producing a sheet-like film according to [1], wherein the adhesive layer having the smallest storage elastic modulus at a temperature of 20 ° C. and an angular frequency of 1,000 rad / sec among the aforementioned adhesive layers is set as The aforementioned reference adhesive layer.

[3] The method for producing a sheet-like film according to [1], wherein the multilayer film system includes a separation film on the outermost surface and adhesion under the outermost surface layer by peeling off the separation film. The adhesive layer; and the adhesive layer below the outermost layer is referred to as the reference adhesive layer.

[4] The method for producing a sheet-like film according to any one of [1] to [3], wherein the multilayer film has a polarizer.

[5] An apparatus for manufacturing a sheet-like film, comprising a cutting section for cutting a multilayer film having an adhesive layer having n layers (n is an integer of 1 or more) and obtaining a sheet-shaped film from the multilayer film, wherein The cutting unit includes a cutting blade configured to enter the multilayer film from the first surface of the multilayer film toward the second surface of the multilayer film, and a control unit that controls the movement of the cutting blade; When any one of the n-layered adhesive layers is used as a reference adhesive layer, the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film satisfies the following relation ( 1).

t / V <1 / ω ₁ (1)

[In the above-mentioned relational expression (1), t represents the thickness (μm) of the multilayer film, and ω ₁ represents the storage elasticity calculated from the measurement value of the dynamic viscoelasticity measurement performed at the frequency sweep of the reference adhesive layer at a temperature of 20 ° C. Frequency when the modulus is 3.0 × 10 ⁵ (Pa) (1 / s)

[6] The device for manufacturing a sheet-like film according to [5], wherein the adhesive layer having the smallest storage elastic modulus among the adhesive layers at a temperature of 20 ° C and an angular frequency of 1,000 rad / sec is set as The aforementioned reference adhesive layer.

[7] The apparatus for producing a sheet-like film according to [5], wherein the multilayer film includes: a topmost separation film; and an adhesive exposed under the outermost surface layer by peeling of the separation film. The adhesive layer; and the adhesive layer below the outermost layer is referred to as the reference adhesive layer.

[8] The apparatus for producing a sheet-like film according to any one of [5] to [7], wherein the multilayer film includes a polarizer.

[9] A method for cutting a multilayer film, which is a method for cutting a multilayer film having an adhesive layer having n layers (n is an integer of 1 or more). The method for cutting a multilayer film includes: The first surface of the multilayer film enters into the multilayer film toward the second surface of the multilayer film, and the cutting step of cutting the multilayer film is performed; and any one of the n-layer adhesive layers is used as a reference adhesive. In the agent layer, the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film satisfies the following relational expression (1).

t / V <1 / ω ₁ (1)

[In the above-mentioned relational expression (1), t represents the thickness (μm) of the multilayer film, and ω ₁ represents the storage elasticity calculated from the measurement value of the dynamic viscoelasticity measurement performed at the frequency sweep of the reference adhesive layer at a temperature of 20 ° C. Frequency when the modulus is 3.0 × 10 ⁵ (Pa) (1 / s)

[10] The method for cutting a multilayer film according to [9], wherein the adhesive layer having the smallest storage elastic modulus at a temperature of 20 ° C. and an angular frequency of 1,000 rad / sec among the adhesive layers is the aforementioned Reference adhesive layer.

[11] The method for cutting a multilayer film according to [9], wherein the multilayer film includes: a topmost separation film; and an adhesive agent exposed under the outermost surface layer by peeling of the separation film. And the adhesive layer below the outermost layer is referred to as the reference adhesive layer.

[12] The method for cutting a multilayer film according to any one of [9] to [11], wherein the multilayer film has a polarizer.

The above and other objects, features, forms, and advantages of the present invention are related to the attached drawings and can be understood from the following detailed description.

10‧‧‧Multilayer film

10a‧‧‧multilayer film

10b‧‧‧multilayer film

10c‧‧‧multilayer film

10d‧‧‧multilayer film

11‧‧‧ sheet film

20‧‧‧ cutting device

21‧‧‧cutting blade member

21a‧‧‧cutting blade member

21b‧‧‧cutting blade member

22‧‧‧Blade receiving board

23‧‧‧bearing platform

24‧‧‧Control Department

31‧‧‧first adhesive layer

60‧‧‧ protective film

61‧‧‧resin film (non-adhesive resin layer)

62‧‧‧Second adhesive layer (adhesive resin layer)

70‧‧‧ separation membrane

100‧‧‧ polarizing plate

101‧‧‧ first surface (layer)

102‧‧‧Second surface (adhesive layer)

102a‧‧‧ convex strip

103‧‧‧Floor

103a‧‧‧ convex strip

211‧‧‧cutting blade

211a‧‧‧cutting blade

211b‧‧‧cutting blade

212a‧‧‧ elastomer

212b‧‧‧ elastomer

213a‧‧‧holding department

Figures 1 (a), (b), and (c) schematically show the cutting steps for obtaining a sheet-like film from a multilayer film An example of a schematic diagram.

2 (a) and 2 (b) are schematic diagrams schematically showing an example of a cutting step for obtaining a sheet-like film from a multilayer film.

3 (a), (b), and (c) are schematic diagrams schematically showing an example of a dicing step for obtaining a sheet-like film from a multilayer film.

Fig. 4 is a cross-sectional view schematically showing a cutting device having a cutting blade.

Fig. 5 shows (a) a sectional view, (b) a perspective view viewed from the bottom, and (c) a bottom view showing an example of a cutting blade member.

Figures 6 (a), (b), and (c) are diagrams schematically showing the cutting operation of the cutting blade.

FIG. 7 is a bottom view showing an example different from the cutting blade member of FIG. 5.

FIG. 8 is an image diagram showing fine stripe-like unevenness generated near the cut surface of the multilayer film surface.

FIG. 9 is a schematic cross-sectional view schematically showing an example of a specific layer configuration of a multilayer film.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all the drawings below, for easy understanding of each component, the display ratio is appropriately adjusted, and the ratio of each component displayed in the drawing and the ratio of the actual component are not necessarily the same.

[Manufacturing method of sheet film]

The manufacturing method of the sheet-like film of this embodiment is a cutting process which has a multilayer film which cuts the adhesive layer which has n layers (n is an integer of 1 or more), and obtains a sheet-like film from a multilayer film. Cutting step package It includes a step of cutting the multilayer film from the first surface of the multilayer film to the second surface of the multilayer film, and cutting the multilayer film.

In the cutting step, the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film is satisfied when any one of the n layers of the foregoing adhesive layers is used as the reference adhesive layer. The following relational expression (1).

t / V <1 / ω ₁ (1)

In the above-mentioned relational expression (1), t represents the thickness (μm) of the multilayer film, and ω ₁ represents the storage elastic modulus calculated based on the measurement value of the dynamic viscoelasticity measurement performed at a frequency sweep of the reference adhesive layer at a temperature of 20 ° C. The frequency (1 / sec) when displayed is 3.0 × 10 ⁵ (Pa).

By making the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film satisfy the above-mentioned relational expression (1), it is possible to suppress the occurrence of fine unevenness in the reference adhesive layer in the cutting step, and as a result, it can be suppressed in the multilayer Stripe-like fine irregularities occur near the cut surface of the film surface. The reference adhesive layer is preferably an adhesive layer that is liable to cause fine unevenness in the cutting step. The method of selecting the reference adhesive layer will be described in detail later.

The present inventors have found that the viscoelastic properties of the adhesive layer in the cutting step are related to the ease of generation of fine unevenness in the adhesive layer. The fine unevenness generated in the adhesive layer is the cause of the fine unevenness generated on the surface of the multilayer film. The viscoelastic properties of the adhesive layer during the cutting step depend on the speed at which the cutting blade passes through the adhesive layer. The inventors have assumed that the approximate time t / V required for a cutting blade that is related to the passage speed to pass through the first surface to the second surface of the multilayer film is very short, and the viscoelastic properties of the adhesive layer can be properly maintained. The agent layer is less prone to generate fine unevenness, and it is difficult to produce fine unevenness near the cut surface of the multilayer film surface. Intensive research has been conducted to complete the above-mentioned relational expression (1). In addition, the speed V (μm / sec) is the speed of the cutting blade on the first surface of the multilayer film, but the speed of the cutting blade in the multilayer film can also be controlled to be about the same speed, so it passes through the first surface of the multilayer film. The time required to reach the second surface can be regarded as approximately the same as the approximate time t / V. Generally, the approximate time t / V is set to less than 9.0 × 10 ^-3 (seconds), and in order to suppress fine unevenness on the surface of the multilayer film, it is preferably set to less than 2.5 × 10 ^-3 (seconds). The approximate time t / V is usually 1.0 × 10 ^-4 (seconds) or more.

From the viewpoint of further suppressing the generation of fine unevenness in the adhesive layer, in the cutting step, the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film is based on the n-layer of the aforementioned adhesive layer. When any one of the adhesive layers is used as the reference adhesive layer, the above relational expression (1) is satisfied, and preferably the following relational expression (2) is satisfied.

t / V <1 / ω ₂ (2)

In the above-mentioned relational expression (2), t represents the thickness (μm) of the multilayer film in the same way as the relational expression (1), and ω ₂ represents the dynamic viscoelasticity measurement performed by the frequency sweep of the reference adhesive layer at a temperature of 20 ° C. The storage elastic modulus calculated from the measured value is displayed as a frequency (1 / sec) at 6.0 × 10 ⁵ (Pa).

<Cutting step>

1 to 3 are schematic diagrams each schematically showing an example of a cutting step of cutting a multilayer film to obtain a sheet-like film from the multilayer film. In FIGS. 1 to 3, the dotted lines indicate the cutting lines in the cutting step. In the example shown in FIG. 1, a long and thin multilayer film 10a is cut in a direction perpendicular to the long side direction using a cutting blade with a straight blade tip (see FIG. 1 (a)) to obtain a chipped multilayer film. 10b (refer to FIG. 1 (b)), and thereafter, using a cutting blade with a straight blade tip to cut the small-sized multilayer film 10b in the longitudinal direction of the original multilayer film 10a (refer to FIG. 1) (b)) to obtain a sheet-like film 11 having a desired size (see FIG. 1 (c)).

In the example shown in FIG. 2, the elongated multilayer film 10 a is punched and cut with a die-cutting blade (see FIG. 2 (a)) to obtain a sheet-like film 11 of a desired size (see FIG. 2 (b )).

In the example shown in FIG. 3, a thin multi-layer film 10a is cut in a direction perpendicular to the long side direction using a cutting blade with a straight blade tip (see FIG. 3 (a)) to obtain a chipped multilayer film. 10c (refer to FIG. 3 (b)), and then press with a die-cutting blade to obtain a sheet-like film 11 having a desired size (refer to FIG. 3 (c)).

The cutting direction of the cutting steps shown in FIGS. 1 to 3 is not particularly limited. When cutting a multilayer film having an orientation characteristic, the cutting direction is determined so that a sheet-like film 11 having a desired orientation characteristic can be obtained. .

In each of the examples shown in Figs. 1 to 3, one or more sheet-like films can be obtained from the multilayer film after one or more cuttings. The number of cuts in the cutting step is not limited. In addition, the above description is for the case where all the cutting in the cutting step is a cutting step, but any cutting is not limited if it is a cutting step. In addition to the cutting step, a cutting step including laser light cutting, rotating circular blade cutting, or the like may also be used. That is, the obtained sheet-like film may be a cut surface including a cutting step. The stripe-shaped fine unevenness easily occurs near the cut portion of the surface of the multilayer film by the press-cutting step. However, in this embodiment, even if all the cutting is a press-cutting step, the generation of such stripe-shaped fine unevenness can be suppressed.

<Cutting step>

Fig. 4 is a cross-sectional view schematically showing a cutting device having a cutting blade. The cutting device 20 shown in FIG. 4 can perform the cutting step of this embodiment. The cutting device 20 is provided with a cutting blade member 21 having a cutting blade, and a control for controlling the cutting blade member 21 to move up and down. The manufacturing portion 24 and the upper surface of the blade receiving plate 22 are provided with a supporting table 23 for supporting the multilayer film 10. The multi-layer film 10 is carried on the supporting table 23 in a manner to be in contact with the blade receiving plate 22. In the multilayer film 10 carried on the supporting table 23, a surface in contact with the blade receiving plate 22 is set as a second surface 102, and a surface on the upper side opposite to the second surface 102 is set as a first surface 101. In the cutting step, the cutting blade member 21 is moved downward so that the cutting blade enters the multilayer film 10 from the first surface 101 toward the second surface 102 of the multilayer film 10. Thereafter, the cutting blade member 21 is moved upward to separate the cutting blade from the multilayer film 10. The multilayer film 10 is cut by this up and down movement of the cutting blade member 21.

FIG. 5 (a) is a cross-sectional view showing the cutting blade member 21a as an example of the cutting blade member 21 shown in FIG. 4 in detail. Fig. 5 (b) is a perspective view showing the cutting blade member 21a as viewed from the bottom, and the a-a cross-sectional view of Fig. 5 (b) corresponds to Fig. 5 (a). Fig. 5 (c) is a bottom view showing the cutting blade member 21a. The cutting blade member 21a includes a cutting blade 211a having a straight blade tip, a holding portion 213a holding the cutting blade 211a, and an elastic body 212a disposed below the holding portion 213a. The lowermost part of the elastic body 212a is located at the same position as or lower than the blade front end portion of the cutting blade 211a.

Figs. 6 (a) to (c) are diagrams schematically showing the state of a cutting blade 211a when the multilayer film 10 is cut by a cutting device having a cutting blade member 21a shown in Figs. 5 (a) to (c). Illustration of cutting action. The cutting operation moves the cutting blade member 21a downward (refer to FIG. 6 (a)), and the lowermost part of the elastic body 212a of the cutting blade member 21a is brought into contact with the first surface 101 of the multilayer film 10 (refer to FIG. 6). (b)). After that, by moving the cutting blade member 21a further downward, the elastic body 212a contracts on the first surface 101 of the multilayer film 10, and only the cutting blade 211a passes through the multilayer film. The first surface 101 of 10 enters the multilayer film 10 until it reaches the blade receiving plate 22 (see FIG. 6 (c)). After the cutting blade 211 a reaches the blade receiving plate 22, the moving direction of the cutting blade member 21 is switched to the upper direction, and the cutting blade 211 a is pulled out from the multilayer film 10. The multilayer film 10 is cut in the laminating direction by the above cutting operation.

The cutting blade 211a included in the cutting blade member 21a is not limited to a cutting blade capable of cutting the multilayer film 10 in a straight line as shown in FIGS. 5 (a) to (c), and can be designed to perform the required cutting . It may be a die-shaped die-cutting blade capable of punching a rectangular sheet-shaped film from the multilayer film 10. An example of a cutting blade member having a die-shaped cutting blade is shown in FIG. 7 in a bottom view. The cutting blade member 21b shown in FIG. 7 includes a cutting blade 211b, a holding member, and an elastic body 212b. The cutting blade member 21b is the same as the cutting blade member 21a shown in FIG. 5 except that the shape of the cutting blade 211b is different. In the structure, the multilayer film 10 can be cut by the same method.

For the cutting blades 211a and 211b, a Thomson blade is preferably used. Thomson blades can also be resin-coated. The elastic bodies 212a and 212b are not limited as long as they can shrink on the surface of the multilayer film, and can sandwich and fix the multilayer film 10 together with the blade receiving plate 22 during cutting. Porous materials such as urethane foam and soft materials such as urethane rubber are preferably used.

In the cutting device of this embodiment, the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film is such that the control section 24 controls the downward moving speed of the cutting blade member 21 to satisfy the relationship (1) .

<Other steps>

The method for producing a sheet-like film according to this embodiment may include steps other than the cutting step described above, and examples thereof include a step for producing a multilayer film for producing a multilayer film, and rolling out a multilayer film wound into a roll. Step of unwinding, conveying step of conveying multilayer film or sheet film, drying step of drying multilayer film or sheet film, and the like.

<Multilayer film>

The multilayer film is not particularly limited as long as it has an adhesive layer. The multilayer film may be, for example, an optical laminated film. In the case of an optical laminated film, even slight irregularities easily cause problems in appearance. The thickness of the multilayer film is, for example, 5 to 3000 μm, and preferably 20 to 500 μm. The layer structure of the multilayer film is preferably such that the contaminant layer is not easily attached to the adhesive layer during the cutting step so that the adhesive layer is not exposed on the outermost surface.

When the multilayer film has an adhesive layer, if a cutting blade is used for cutting, stripe-like fine unevenness is easily generated near the cut surface of the multilayer film surface. However, the method for manufacturing a sheet-like film according to this embodiment can suppress such fine unevenness The generation. More specifically, the fine unevenness is often a stripe-shaped ridge extending in a direction substantially parallel to the cutting surface, and most of it is generated on the second surface in contact with the blade receiving plate. Although the mechanism for the generation of fine unevenness is not clear, as for a possible mechanism, it can be listed as follows: through the entry of the cutting blade, different shear stresses are generated in each layer, which acts on the two layers in contact with the adhesive layer. Different shear stress causes local deformation of the adhesive layer. It is speculated that this local deformation is due to the softer adhesive layer than the other layers.

FIG. 8 is an image diagram showing fine stripe-like unevenness generated near the cut surface of the multilayer film surface. The mechanism for generating fine unevenness using FIG. 8 is one possible mechanism. The fine unevenness suppressed by the method for manufacturing a sheet-shaped film according to this embodiment is not limited to the unevenness caused by this mechanism. The figure schematically shows the fine unevenness. In FIG. 8, the multilayer film 10 as a cutting target is assumed to include a layer 101, an adhesive layer 102, and a layer 103. When the cutting blade 211 enters the multilayer film 10, different shear stresses are generated in each layer. 102 is softer than the adjacent layers 101 and 103, and the shear stress acting on the two layers 101 and 103 is different, which causes a part of the vicinity of the cutting surface of the adhesive layer 102 to swell slightly to form a convex strip 102a. Due to the convex strips 102a of the adhesive layer 102, the layer 103 adjacent to the adhesive layer 102 is sometimes slightly raised to form the convex strips 103a. As described above, the ridges 102a formed on the adhesive layer 102 and the ridges 103a formed on the layer 103 cause the appearance of streak-like irregularities.

[Adhesive layer]

The adhesive layer may be composed of a (meth) acrylic-based, rubber-based, urethane-based, ester-based, silicone-based, or polyvinyl ether-based resin as a main component. Among them, a (meth) acrylic resin excellent in transparency, weather resistance, heat resistance and the like as a base polymer is preferably an adhesive composition. The adhesive composition may be an active energy ray hardening type or a thermosetting type.

As the (meth) acrylic resin (base polymer) used in the adhesive composition, for example, butyl (meth) acrylate, ethyl (meth) acrylate, and isooctyl (meth) acrylate are suitably used. A polymer or copolymer in which one or two or more of (meth) acrylates such as esters and 2-ethylhexyl (meth) acrylate are used as monomers. Preferably, the base polymer is copolymerized with a polar monomer. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, and (meth) acrylic acid. Monomers having a carboxyl group, a hydroxyl group, a sulfonylamino group, an amino group, and an epoxy group, such as N, N-dimethylaminoethyl ester and glycidyl (meth) acrylate.

The adhesive composition may include only the base polymer described above, and usually further contains a crosslinking agent. Examples of the cross-linking agent include: a metal ion having a valence of two or more that forms a carboxylic acid metal salt with a carboxyl group, a polyamine compound that forms a amide bond with a carboxyl group, a polyepoxide compound that forms an ester bond with a carboxyl group, or a polyvalent compound Alcohols, polyisocyanate compounds that form amido bonds with carboxyl groups. Among these, a polyisocyanate compound is preferable.

The active energy ray-curable adhesive composition refers to a property that is hardened by being irradiated with active energy rays such as ultraviolet rays or electron rays, and has adhesiveness before irradiation with active energy rays, and can be adhered to an adherend such as a film. An adhesive composition that adjusts the properties of adhesion by irradiating active energy rays to harden. The active energy ray-curable adhesive composition is preferably an ultraviolet-curable type. The active energy ray-curable adhesive composition contains an active energy ray polymerizable compound in addition to a base polymer and a crosslinking agent. If necessary, a photopolymerization initiator, a photosensitizer, and the like may be further contained.

The adhesive composition may contain fine particles, beads (resin beads, glass beads, etc.), glass fibers, resins other than the base polymer, tackifiers, fillers (metal powder or other Inorganic powder, etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers, corrosion inhibitors, photopolymerization starters and other additives.

The organic solvent diluent of the adhesive composition can be coated on a substrate, and an adhesive layer can be formed by drying. When an active energy ray-curable adhesive composition is used, a hardened product having a desired degree of hardening can be obtained by irradiating the formed adhesive layer with an active energy ray.

The thickness of the adhesive layer may be, for example, 1 to 40 μm. When the thickness of the adhesive layer is 1 to 40 μm, fine stripe-like unevenness is easily generated by the cutting step. However, according to the method for manufacturing the sheet film of this embodiment, even if the thickness of the adhesive layer is 1 to 40 μm, It suppresses the generation of fine unevenness in stripes.

The adhesive layer can display a storage elastic modulus of 0.15 to 1 MPa at a temperature of 20 ° C and an angular frequency of 1,000 rad / sec. When the adhesive layer has the above-mentioned storage elastic modulus, it is softer than other layers and easily generates fine unevenness. However, according to the manufacturing method of the sheet film of this embodiment, the storage elastic modulus of the adhesive layer at a temperature of 20 ° C is 0.15 to 1MPa, can still suppress the generation of fine unevenness.

The storage elastic modulus of the adhesive layer can be measured using a commercially available viscoelasticity measuring device such as a viscoelasticity measuring device "DYNAMIC ANALYZER RDA II" manufactured by REOMETRIC.

Examples of the method for adjusting the storage elastic modulus to the above range include adding an oligomer to a base polymer or an adhesive composition further containing a crosslinking agent, and specifically, a urethane (formaldehyde Group) an acrylate-based oligomer to obtain an active energy ray-curable adhesive composition (preferably an ultraviolet-curable adhesive composition). More preferably, the active energy ray is irradiated to moderately harden the adhesive layer.

[Reference adhesive layer]

The multilayer film manufactured by the manufacturing method of the sheet-like film of this embodiment, or the manufacturing method of the sheet-like film of this embodiment has an n-layer (n is an integer of 1 or more) adhesive layer. When there is one adhesive layer included in the multilayer film, the speed of the cutting blade is controlled to satisfy the above-mentioned relational expression (1) by using the adhesive layer as a reference adhesive layer. When the adhesive layer included in the multilayer film is a plurality of layers, it is preferable to use the adhesive layer that is prone to generate unevenness in the cutting step as a reference adhesive layer. The adhesive layers exemplified below in i) and ii) are exemplified by the present inventor's use of an adhesive layer that is prone to generate unevenness in the cutting step as a reference adhesive layer.

i) Store the adhesive layer with the smallest modulus of elasticity at a temperature of 20 ℃, ii) The multilayer film has a topmost separation membrane and an adhesive layer under the outermost surface layer which is exposed by peeling of the separation membrane, and the adhesive layer below the outermost layer.

In the method for producing a sheet-like film according to this embodiment, it is preferable that when any of the n-layer adhesive layers is used as the reference adhesive layer, the speed of the cutting blade satisfies the relational expression (1).

[Example of layer constitution of multilayer film]

FIG. 9 is a schematic cross-sectional view schematically showing an example of a specific layer configuration of a multilayer film manufactured by the method for manufacturing a sheet-like film according to this embodiment or the method for manufacturing a sheet-like film according to this embodiment. The multilayer film 10d is a polarizing plate 100 including a polarizer (not shown in FIG. 9), a protective film 60 laminated on one surface thereof, a first adhesive layer 31 laminated on the other surface, and The peelable separation film 70 on the outer surface of the first adhesive layer 31 is used to temporarily protect the first adhesive layer 31. On the other hand, the surface on the protective film 60 side (the surface to which the protective film 60 is adhered) and the surface of the first adhesive layer 31 (the surface to which the first adhesive layer 31 is adhered) in the polarizing plate 100 may be, for example, a protective film or other optical The surface of a film, or a layer attached to a film.

One surface of the protective film 60 may be adhesive, and the other surface may be non-adhesive, and the polarizing plate 100 may be adhered and laminated on one of the adhesive surfaces. Examples of such a protective film 60 include a so-called self-adhesive protective film. The self-adhesive protective film system is, for example, a resin film composed of a non-adhesive resin layer 61 including a non-adhesive resin, and an adhesive resin layer 62 including a self-adhesive resin. Examples of the self-adhesive protective film include "TORETECH" (manufactured by TORAY FILM Processing Co., Ltd.). In addition, a protective film composed of a resin film (base film) 61 and a second adhesive layer 62 laminated on the resin film may be laminated on the polarizing plate 100 through the adhesive layer. When the protective film 60 has the second adhesive layer 62, the storage elastic modulus thereof is generally larger than the storage elastic modulus of the first adhesive layer.

The polarizing plate 100 is a polarizing element including at least a polarizer and a first adhesive layer 31, and generally further includes a protective film adhered to one or both sides of the polarizer. The polarizing plate 100 may include, in addition to a protective film, another optical film such as a film having an optical function different from that of a polarizer, or a layer added to a film such as an optical layer. Various optical films including a protective film can be passed through an adhesive layer Or stick the adhesive layer. The polarizing plate 100 may be one including an adhesive layer, or may be one not including an adhesive layer. When the adhesive layer is included, the adhesive layer included in the polarizing plate 100 becomes one of the adhesive layers included in the n layers of the multilayer film.

The thickness of the polarizing plate 100 is usually 20 to 200 μm, preferably 30 to 150 μm, more preferably 40 to 120 μm, and even more preferably 50 to 100 μm.

The multilayer film 10d may be a raw material film continuously rolled out and transported from a film roll, and other raw material films continuously rolled out from the film roll may be laminated, and the obtained elongated laminated film may be wound into a roll shape. Produced by a so-called roll-to-roll method, it can also be a multilayer film obtained by cutting it. In the method for manufacturing a sheet-like film according to this embodiment, a multilayer film 10d is cut in a cutting step to produce a sheet-like film.

When the multilayer film 10 d includes the first adhesive layer 31 and the second adhesive layer 62 as the adhesive layer, the first adhesive layer 31 on which the peelable separation film 70 is laminated is usually prone to fine unevenness during the cutting step. This is thought to be because the separation film 70 is peeled or displaced due to the effect of shear stress, and the displacement of the adhesive layer is fixed.

When the multilayer film 10d is cut by the cutting device shown in FIG. 4, the protective film 60 side can be used as the first surface, and the separation film 70 side can be used as the second surface, so that the separation film 70 is in contact with the blade receiving plate 22. It is carried on the bearing table 23 for cutting, and the separation film 70 side can be used as the first surface, and the protective film 60 side can be used as the second surface, so that the resin film 61 constituting the protective film 60 is in contact with the blade receiving plate 22 The method is carried on the supporting platform 23 for cutting. According to the method for manufacturing a sheet-like film according to this embodiment, even if the multi-layer film 10d is carried in any direction, it is possible to suppress generation of fine unevenness in a stripe shape due to the cutting step.

Although the shape of the uncut multilayer film 10d is not particularly limited, it is generally elongated (belt shape). Although the length of the slender direction and the width direction of the uncut multilayer film 10d is not particularly limited, the length of the slender direction of the multilayer film 10d is generally 100m to 20,000m, and the length of the width direction is 1000mm to 1500mm. In addition, after the multilayer film 10d is cut into small pieces of the multilayer film 10d, a cutting step may be performed. At this time, although the shape of the small-piece multilayer film 10d is not particularly limited, it is preferably a square shape having long sides and short sides, and generally a rectangular shape. The length of the long side and the short side is not particularly limited, for example, the length of the long side is 900 mm or less, and the length of the short side is 800 mm or less.

The size, shape, and cutting angle of the sheet-like film are not particularly limited. The sheet-like film is preferably a square shape, and more preferably a square shape having long sides and short sides. This square shape is preferably rectangular. When the sheet-like film is rectangular, the length of the long side is, for example, 50 mm to 300 mm, and preferably 70 mm to 200 mm. The length of the short side is, for example, 30 mm to 200 mm, and preferably 40 mm to 100 mm. In the press-cutting step, the minute irregularities generated on the surface of the sheet-like film near the cutting surface, the smaller the size of the sheet-like film, the more conspicuous it becomes, and it is easy to become an appearance defect. Even when the size of the sheet-like film is small, fine unevenness can be prevented.

(1) Polarizer

A polarizer is an absorption-type polarizer having the property of absorbing linearly polarized light having a vibration plane parallel to its absorption axis and penetrating linearly polarized light having a vibration plane perpendicular to the absorption axis (parallel to the transmission axis). A polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. The polarizer may include, for example, a step of uniaxially stretching the polyvinyl alcohol-based resin film, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye to adsorb the dichroic dye, and an adsorbed solution with a boric acid aqueous solution. Process for processing a polyvinyl alcohol-based resin film of a dichroic pigment, and It is manufactured by a method in which an acid aqueous solution is subjected to a washing step.

The thickness of the polarizer is preferably 50 μm or less, and more preferably 30 μm or less. Setting the thickness of the polarizer to 30 μm or less is favorable for the polarizing plate 100 and even the thinning of the image display device. The thickness of the polarizer is usually 2 μm or more (for example, 5 μm or more).

(2) Protective film

The protective film that can be laminated on one or both sides of the polarizer may be a thermoplastic resin (for example, a chain polyolefin resin (polypropylene resin, etc.), a ring-shaped resin, etc.) that has translucency (preferably optically transparent). Polyolefin-based resins (such as norbornene-based resins) and other polyolefin-based resins; cellulose resins such as triethyl cellulose and diethyl cellulose; polyethylene terephthalate, polybutylene terephthalate Polyester resins such as diesters; polycarbonate resins; (meth) acrylic resins such as methyl methacrylate resins; polystyrene resins; polyvinyl chloride resins; acrylonitrile-butadiene-benzene Vinyl resin; Acrylonitrile-styrene resin; Polyvinyl acetate resin; Polyvinylidene chloride resin; Polyamine resin; Polyacetal resin; Modified polyphenylene ether resin; Polyfluorene resin Resin; polyether fluorene resin; polyarylate resin; polyfluorene amine imine resin; polyfluorene amine resin; etc.]. Among them, polyolefin resins and cellulose resins are preferably used. The "(meth) acrylic resin" in the present specification means at least one selected from the group consisting of an acrylic resin and a methacrylic resin. The same applies to other terms with "(methyl)".

The thickness of the protective film is usually 1 to 100 μm, but from the viewpoints of strength, operability, etc., it is preferably 5 to 60 μm, and more preferably 5 to 50 μm.

The protective film may include a hard coat layer, an anti-glare layer, a light diffusion layer, and a retardation layer (a retardation layer having a retardation value of 1/4 wavelength) on at least one of the surfaces (the surface opposite to the polarizer). Etc.), anti-reflection layer, antistatic layer, antifouling layer and other surface treatment layers (coatings) or optical layers.

The protective film can be adhered to a polarizer via an adhesive layer, for example. As the adhesive forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive can be used, and a water-based adhesive or an active energy ray-curable adhesive is preferred.

(3) Other optical films

The polarizing plate 100 may include other optical films other than a polarizer and a protective film, and representative examples thereof include a brightness enhancement film and a retardation film. When the polarizing plate 100 includes another optical film, the protective film 60 may be laminated on the surface of the optical film.

(4) The first adhesive layer

The first adhesive layer 31 is an adhesive layer disposed on the outermost surface of the polarizing plate 100, and can be used to adhere a multilayer film to an image display element (such as a liquid crystal cell) or other optical members. The thickness of the first adhesive layer 31 may be 1 to 40 μm, but from the viewpoint of thinning the polarizing plate 100 and the viewpoint of maintaining good processability and suppressing the dimensional change of the polarizing plate 100, it is preferably set to 3 To 25 μm (for example, 3 to 20 μm, more preferably 3 to 15 μm). The material of the first adhesive layer 31 is applied to the description of the above-mentioned adhesive layer.

(5) Separation membrane

The separation film 70 is a film temporarily adhered to protect the surface until the first adhesive layer 31 is adhered to an image display element (for example, a liquid crystal cell) or other optical members. The separation film 70 is generally composed of a thermoplastic resin film subjected to a release treatment on one side, and the release treatment surface is adhered to the first adhesive layer 31. The thermoplastic resin constituting the separation membrane 70 may be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, or a polyester such as polyethylene terephthalate or polyethylene naphthalate. Department of resin and so on. On the surface of the third adhesive layer 32, an optical film such as the brightness enhancement film 50 may be pasted, and the same separation film as described above may be pasted to temporarily protect the surface. The thickness of the separation membrane 70 is, for example, 10 to 100 μm. When the aforementioned storage elastic modulus of the first adhesive layer 31 is 0.15 to 1 MPa, if the thickness of the separation membrane in direct contact with the first adhesive layer 31 is 50 μm or less, during the cutting step, due to the first adhesion here, The fine unevenness of the agent layer 31 may increase, and the method of the present invention is preferably applied.

(6) Protective film

The protective film 60 is composed of a resin film 61 and a non-adhesive resin layer 62 or a second adhesive layer 62 laminated on the resin film. The protective film 60 is a film for protecting the surface of the polarizing plate 100. Generally, for example, after the polarizing plate with the protective film is attached to an image display element or other optical member, an adhesive resin layer 62 or a second adhesive having the protective film is adhered. The agent layer 62 is peeled and removed together.

The resin constituting the resin film 61 may be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, or a polyester resin such as polyethylene terephthalate or polyethylene naphthalate. Thermoplastic resins such as resins and polycarbonate resins. Polyester resins such as polyethylene terephthalate are preferred. The resin film 61 may have a single-layer structure or a multi-layer structure, but from the viewpoints of ease of production and manufacturing cost, a single-layer structure is preferred. The second adhesive layer 62 refers to the description of the first adhesive layer 31 described above.

[Production Device for Sheet Film]

The manufacturing apparatus of the sheet-like film of this embodiment has a cutting part which cuts the multilayer film which has an adhesive layer, and obtains a sheet-like film from a multilayer film. The cutting unit includes a cutting blade that can be placed in the multilayer film from a first surface of the multilayer film toward a second surface of the multilayer film. In the manufacturing method of a sheet-shaped film to which a cutting part is applied, the said cutting device was demonstrated. About the manufacturing method of the sheet-like film suitable for a multilayer film system, the said multilayer film was demonstrated.

The manufacturing apparatus of the sheet-like film of this embodiment may be provided with the other than the said cutting part. The constituent elements include, for example, a multilayer film manufacturing section for manufacturing a multilayer film, a roll-out section for winding a roll-shaped multilayer film, a transport section for transporting a multilayer film or a sheet film, a dried multilayer film or a sheet film Drying section and so on.

[Cutting method of multilayer film]

The cutting method of the multilayer film of this embodiment includes a cutting step of cutting the multilayer film by moving a cutting blade into the multilayer film from the first surface of the multilayer film to the second surface of the multilayer film. The dicing method is a description of the above-mentioned dicing steps in the method for producing a sheet-like film.

[Example]

Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited to these examples.

[Multilayer film A]

As for the multilayer film A to be cut, a cyclic olefin polymer (COP) polarizing plate (material for mass production of SRD341) with a protective film having a thickness of 185 μm and a length of 300 mm on the long side and a length of 210 mm on the short side was used. The COP polarizing plate with protective film is formed by laminating a protective film (58 μm), a TAC film (25 μm) as a protective film, a PVA film (12 μm) as a polarizer, a COP film (23 μm), and first adhesion. The structure of an agent layer (20 μm) and a PET film (38 μm) as a separation membrane. One side of the protective film is adhesive, and the other side is non-adhesive. The one side of the adhesive film is in contact with the TAC film and adhered.

The storage modulus of the first adhesive layer was 0.34 MPa at a temperature of 20 ° C and an angular frequency of 1,000 rad / sec. Regarding the multilayer film A, the first adhesive layer is used as a reference adhesive layer. Regarding the reference adhesive layer (first adhesive layer), a dynamic viscoelasticity measurement at a frequency of 20 ° C was performed by using a viscoelasticity measuring device "DYNAMIC ANALYZER RDA II" manufactured by REOMETRIC, and a storage elastic modulus was derived from the measured values. The frequency ω ₁ when the number is displayed as 3.0 × 10 ⁵ (Pa) is 1.20 × 10 ² (1 / second). Similarly, the frequency ω ₂ when the storage elastic modulus was 6.0 × 10 ⁵ (Pa) was derived from the measured values and was 6.03 × 10 ² (1 / second).

[Multilayer film B]

The multilayer film B uses an adhesive composition different from the adhesive composition constituting the first adhesive layer of the multilayer film A as the adhesive composition constituting the first adhesive layer, except that the thickness of the first adhesive layer is The thickness is 15 μm, and the thickness of the multilayer film B is other than 180 μm. The structure is the same as that of the multilayer film A. The storage modulus of the first adhesive layer was 0.65 MPa at a temperature of 20 ° C and an angular frequency of 1,000 rad / sec. The multilayer film B is based on the first adhesive layer as a reference adhesive layer. Regarding the reference adhesive layer, a dynamic viscoelasticity measurement at a frequency of 20 ° C was performed using a viscoelasticity measuring device "DYNAMIC ANALYZER RDA II" manufactured by REOMETRIC. The storage elastic modulus was derived from the measured values and displayed as 3.0 × 10 ⁵ The frequency ω ₁ at (Pa) is 1.62 × 10 (1 / second). In the same manner, the frequency ω ₂ when the storage elastic modulus was 6.0 × 10 ⁵ (Pa) was derived from the measured values, which was 1.38 × 10 ² (1 / second).

[Example 1]

(Cutting test)

The cutting test was performed using a cutting device shown in FIG. 4, which is provided with a cutting blade member 21 a shown in FIG. 5. As the cutting blade 211a of the cutting blade member 21a, a Thomson blade (manufactured by Takino Seiki Co., Ltd.) having a length of 614 mm in the longitudinal direction was used.

First, the multilayer film A is carried on the supporting table 23 so as to be in contact with the blade receiving plate 22. At this time, the PET film (58 μm) constituting the protective film is placed on the upper side, and the PET film (38 μm) as the separation film is placed on the lower side. Then, the cutting blade 211a was allowed to enter the multilayer film A on the surface of the protective film at a speed of 7.6 × 10 ⁴ (μm / sec), and cut in a direction perpendicular to the absorption axis to divide the COP polarizing plate with the protective film into two equal parts. .

(Evaluation of streaks)

Five samples were subjected to a cutting test, and the five samples were evaluated visually for the presence or absence of streaks in the vicinity of the cut surface of the surface of the cut piece divided into two. The evaluation results are shown in Table 1.

[Example 2]

In the cutting test, the cutting test was performed in the same manner as in Example 1 except that the cutting blade 211a was allowed to enter the multilayer film A at a speed of 1.2 × 10 ⁵ μm / sec on the surface of the protective film, and the presence or absence of streaks was evaluated. Bump. The evaluation results are shown in Table 1.

[Example 3]

The cutting test was performed in the same manner as in Example 1 except that the multilayer film B was used instead of the multilayer film A, and the cutting blade 211a entered the multilayer film B at a speed of 2.1 × 10 ⁴ μm / sec on the surface of the protective film. A cutting test was performed to evaluate the presence or absence of streaks. The evaluation results are shown in Table 1.

[Example 4]

In the cutting test, a cutting test was performed in the same manner as in Example 3, except that the cutting blade 211a was allowed to enter the multilayer film B on the surface of the protective film at a speed of 7.6 × 10 ⁴ μm / second, and the presence or absence of streaks was evaluated. Bump. The evaluation results are shown in Table 1.

[Comparative Example 1]

In the cutting test, the cutting test was performed in the same manner as in Example 1 except that the cutting blade 211a was allowed to enter the multilayer film A at a speed of 6.6 × 10 ³ μm / sec on the surface of the protective film, and the presence or absence of streaks was evaluated. Bump. The evaluation results are shown in Table 1.

[Comparative Example 2]

In the cutting test, a cutting test was performed in the same manner as in Example 1 except that the cutting blade 211a was allowed to enter the multilayer film A at a speed of 2.1 × 10 ⁴ μm / sec on the surface of the protective film, and the presence or absence of streaks was evaluated. Bump. The evaluation results are shown in Table 1.

The above is a description of the embodiments of the present invention, but the embodiments disclosed this time are illustrative in all respects, and are not limited. The scope of the present invention is shown according to the scope of the patent application, and it includes all changes within the same meaning and scope as the scope of the patent application.

Claims (18)

A method for manufacturing a sheet-shaped film, comprising a cutting step of cutting a multilayer film having an adhesive layer of n layers to obtain a sheet-shaped film from the multilayer film, where n is an integer of 1 or more, and the cutting step includes a cutting blade. From the first surface of the multi-layer film to the second surface of the multi-layer film, enter the multi-layer film, and the cutting step of cutting the multi-layer film is performed by using any of the n-layers of the aforementioned adhesive layers When the adhesive layer is a reference, the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film satisfies the following relationship (1), and t / V <1 / ω ₁ (1) the above relationship In formula (1), t represents the thickness (μm) of the multilayer film, and ω ₁ represents the storage elastic modulus calculated based on the measurement value of the dynamic viscoelasticity measurement performed by the frequency sweep of the reference adhesive layer at a temperature of 20 ° C. The frequency (1 / sec) at 3.0 × 10 ⁵ (Pa). The method for manufacturing a sheet-like film according to item 1 of the scope of patent application, wherein the adhesive layer having the smallest storage elastic modulus among the aforementioned adhesive layers at a temperature of 20 ° C and an angular frequency of 1,000 rad / sec is set as The aforementioned reference adhesive layer. The method for manufacturing a sheet-like film according to item 1 of the scope of the patent application, wherein the multi-layered film system includes: a separation film on the outermost layer, and adhesion under the outermost surface layer by peeling of the separation film The adhesive layer; and the adhesive layer below the outermost layer is referred to as the reference adhesive layer. The method for manufacturing a sheet-like film according to item 1 of the scope of patent application, wherein the multilayer film has a polarizer. The method for manufacturing a sheet-like film according to item 1 of the scope of patent application, wherein the thickness of the reference adhesive layer is 1 to 20 μm. The method for manufacturing a sheet-like film according to any one of claims 1 to 5, wherein the aforementioned cutting blade is a Thomson blade. An apparatus for manufacturing a sheet-like film, comprising a cutting section for cutting a multilayer film having an adhesive layer of n layers and obtaining a sheet-shaped film from the multilayer film, where n is an integer of 1 or more, and the cutting section is provided with: A cutting blade that can enter the multilayer film from the first surface of the multilayer film to the second surface of the multilayer film; and a control part that controls the movement of the cutting blade; the control part is for adhering the n layers of the adhesive When any one of the adhesive layers is used as the reference adhesive layer, it is performed so that the speed V (μm / sec) of the cutting blade on the first surface of the multilayer film satisfies the following relational expression (1). Control, t / V <1 / ω ₁ (1) In the above relational expression (1), t represents the thickness (μm) of the multilayer film, and ω ₁ represents the frequency scan performed at a temperature of 20 ° C based on the reference adhesive layer described above. The storage elastic modulus calculated from the measured value of the dynamic viscoelasticity measurement is shown as a frequency (1 / second) at 3.0 × 10 ⁵ (Pa). The device for manufacturing a sheet-like film according to item 7 of the scope of patent application, wherein the adhesive layer having the smallest storage modulus of elasticity among the aforementioned adhesive layers at a temperature of 20 ° C and an angular frequency of 1,000 rad / sec is set as The aforementioned reference adhesive layer. The apparatus for manufacturing a sheet-like film according to item 7 of the scope of the patent application, wherein the multilayer film includes: a topmost separation film; and an adhesion under the outermost surface layer by peeling of the separation film. The adhesive layer; and the adhesive layer below the outermost layer is referred to as the reference adhesive layer. The device for manufacturing a sheet-like film according to item 7 of the scope of application for a patent, wherein the multilayer film has a polarizer. The device for manufacturing a sheet-like film according to item 7 of the scope of patent application, wherein the thickness of the reference adhesive layer is 1 to 20 μm. According to the device for manufacturing a sheet-like film according to any one of claims 7 to 11, in the patent application scope, wherein the cutting blade is a Thomson blade. A cutting method of a multilayer film is to cut a multilayer film having an adhesive layer of n layers, where n is an integer of 1 or more. The cutting method of the multilayer film includes: pressing a cutting blade from the first surface of the multilayer film toward the foregoing. The second surface of the multilayer film enters into the multilayer film, and the cutting step of cutting the multilayer film is performed; when any one of the n layers of the adhesive layers is used as a reference adhesive layer, the aforementioned cutting blade The speed V (μm / sec) of the first surface of the multilayer film satisfies the following relationship (1), t / V <1 / ω ₁ (1) In the relationship (1), t represents the Thickness (μm), ω ₁ represents the frequency at which the storage elastic modulus calculated based on the measured value of the dynamic viscoelasticity measurement performed by the frequency sweep of the reference adhesive layer at a temperature of 20 ° C is 3.0 × 10 ⁵ (Pa) (1 second). The method for cutting a multilayer film according to item 13 of the scope of patent application, wherein the adhesive layer having the smallest storage modulus of elasticity among the aforementioned adhesive layers at a temperature of 20 ° C and an angular frequency of 1,000 rad / sec is set as the foregoing Reference adhesive layer. The method for cutting a multilayer film according to item 13 of the scope of the patent application, wherein the multilayer film has: a topmost separation film; and an adhesive agent exposed under the topmost surface layer by peeling the separation film. And the adhesive layer below the outermost layer is referred to as the reference adhesive layer. The method for cutting a multilayer film according to item 13 of the scope of application, wherein the multilayer film has a polarizer. The method for cutting a multilayer film according to item 13 of the scope of the patent application, wherein the thickness of the reference adhesive layer is 1 to 20 μm. The method for cutting a multilayer film according to any one of claims 13 to 17, wherein the aforementioned cutting blade is a Thomson blade.