JP4182244B2 - Method for producing functional film with pressure sensitive adhesive - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a functional film with a pressure sensitive adhesive.
[0002]
[Prior art]
Functional films, such as optical functional films such as polarizing films and retardation films, are often used in a state where a pressure-sensitive adhesive is laminated. This is because a functional film with a pressure-sensitive adhesive can be easily bonded and laminated to other members and other functional films. For example, bonding a polarizing plate with a pressure sensitive adhesive to a liquid crystal cell to form a liquid crystal display is widely performed. In addition, when a polarizing film and a retardation film are laminated to form an elliptical polarizing plate or a circular polarizing plate, or when an antireflection film is laminated to a polarizing film to form an antireflection polarizing film, the reflective film is laminated to the polarizing film. For example, when a reflective polarizing film is used, a film having a pressure-sensitive adhesive layer provided on one film is generally attached to the other film.
[0003]
Various proposals have been made for such functional films with pressure-sensitive adhesives or pressure-sensitive adhesive films therefor. For example, in Japanese Patent Publication No. 4-50352 (Patent Document 1), in producing a laminate of a pressure-sensitive adhesive film composed of a support layer made of a thermoplastic resin, a pressure-sensitive adhesive layer, and a release layer, Extruding the support layer into a film, on the other hand, the pressure-sensitive adhesive layer and the release layer are combined and laminated in a die, and this is co-extruded so that the pressure-sensitive adhesive layer is on the support layer side, Furthermore, it is disclosed that a pressure-sensitive adhesive film is produced by pressure-bonding three layers with a roll immediately after extrusion. Japanese Patent Laid-Open No. 9-243824 (Patent Document 2) discloses a surface protective pressure-sensitive adhesive tape that is provided with a pressure-sensitive adhesive layer on one side of a base film and is bonded to a polarizing film or a retardation film for a liquid crystal display. Discloses that the adhesive force between the pressure-sensitive adhesive layer and the base film is smaller than the adhesive force between the pressure-sensitive adhesive layer and the polarizing plate or the retardation film. Further, JP 2000-111731 A (Patent Document 3) discloses that a protective film affixed to the adherend surface of a polarizing film is half-cut into a frame shape in the vicinity of the peripheral edge of the polarizing plate, leaving a peripheral edge for protection. It is disclosed that a polarizing plate laminate is produced by peeling a film and attaching another pressure-sensitive adhesive sheet to the exposed adherend surface of a polarizing film.
[0004]
And, press bonding and roll bonding are adopted for the process of laminating a pressure sensitive adhesive on an optical functional film such as a polarizing film or a retardation film, but the pressure sensitive adhesive is wider than the width of the functional film. If the width is too large, the protruding pressure-sensitive adhesive will cause the press machine and roll to become dirty, which is not suitable for continuous production. Therefore, generally, the width of the pressure-sensitive adhesive is made smaller than the width of the functional film. However, in this case, since the functional film can only be actually used in the portion where the pressure-sensitive adhesive is laminated, the entire width of the functional film cannot be used.
[0005]
When laminating with the width of the pressure-sensitive adhesive smaller than the width of the functional film, the pressure-sensitive adhesive is removed to the end of the functional film by slitting the part where the pressure-sensitive adhesive is not provided. It is a laminated functional film with a full width pressure sensitive adhesive. However, in this method, the functional film is cut off, and further slit scraps may cause contamination of the subsequent process.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 4-50352 [Patent Document 2]
JP-A-9-243824 [Patent Document 3]
JP 2000-111731 A [0007]
[Problems to be solved by the invention]
Then, the subject of this invention is manufacturing a functional film with a pressure sensitive adhesive by which the pressure sensitive adhesive was laminated | stacked over the full width of the functional film, without discarding a functional film.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, in the present invention, a functional film having a smaller width is laminated on the first process film; separately, a pressure-sensitive adhesive layer is formed on the second process film, and the width of the pressure-sensitive adhesive layer is formed here. Is not greater than the width of the second process film and greater than the width of the functional film, but not greater than the width of the first process film, and the pressure sensitive adhesive adheres to the second process film. The adhesive force to the first process film is larger than the force; the functional film laminated on the first process film and the pressure-sensitive adhesive layer formed on the second process film are bonded together, In that case, it presses so that the exposed surface of a pressure sensitive adhesive layer may contact a 1st process film; Then, a functional film with a pressure sensitive adhesive is peeled off from a functional film then. The There is provided a method of forming.
[0009]
The second step film used here is preferably subjected to a mold release treatment on the surface on which the pressure-sensitive adhesive layer is formed. Moreover, bonding of the functional film laminated | stacked on the 1st process film and the pressure sensitive adhesive layer formed in the 2nd process film can be advantageously performed by roll bonding.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating the method of the present invention step by step.
[0011]
As shown in FIG. 1A, in the present invention, first, the functional film 20 is laminated on the first process film 11, while the pressure-sensitive adhesive layer 31 is formed on the second process film 12. . The relationship between the width a of the first process film 11 and the width b of the functional film 20 is a> b. And the functional film 20 is laminated | stacked on the center of the width direction of the 1st process film 11, and the 1st process film 11 protrudes from the functional film 20 in the width direction both sides. The relationship between the width c of the second process film 12 and the width d of the pressure-sensitive adhesive layer 31 is that the latter is not larger than the former, in other words, the latter is the same as or smaller than the former, and therefore c ≧ d It is. The width d of the pressure-sensitive adhesive layer 31 is larger than the width b of the functional film 20, but not larger than the width a of the first process film 11, in other words, the same as the width a of the first process film 20. Or smaller, and therefore, a ≧ d> b.
[0012]
In addition, the pressure-sensitive adhesive layer 31 is bonded to the second process film 12 at this stage, but the adhesive force thereof is greater to the first process film 11 than to the second process film 12. It is important to use one. Thus, after using the thing which has the adhesive force with respect to the pressure sensitive adhesive layer 31 as the 1st process film 11 and the 2nd process film 12, after passing through the bonding and press process mentioned later, a 1st When the process film 11 is peeled from the functional film 20, the pressure-sensitive adhesive layer 31 in contact with the first process film 11 is transferred to the first process film 11 side.
[0013]
The functional film 20 laminated on the first process film 11 and the pressure-sensitive adhesive layer 31 formed on the second process film 12 are then functional films as shown in FIG. The 20 side and the pressure sensitive adhesive layer 31 side are bonded together. At this time, as is clear from the above definition, the width b of the functional film 20 is the smallest, but in other words, the functional film 20 is located approximately at the center of the pressure-sensitive adhesive layer 31. The pressure adhesive layer 31 is bonded so that both ends in the width direction protrude from both ends in the width direction of the functional film 20.
[0014]
Subsequently, as shown in FIG. 1C, the exposed surface of the pressure-sensitive adhesive layer 31, that is, the both end portions in the width direction protruding from the functional film 20 are pressed so as to contact the first process film 11. To do. Thereby, the pressure-sensitive adhesive layer 31 is bonded to the first process film 11 on the surface not bonded to the functional film 20. The pressure at the time of pressing may be such that the exposed surface of the pressure-sensitive adhesive layer 31 is in contact with the first process film 11 and is, for example, about 50 to 500 kPa. If the pressure becomes too large, the optical function of the functional film 20 may be affected. Therefore, it is desirable to set the pressure so as not to cause such an effect.
[0015]
Thereafter, the first process film 11 is peeled from the functional film 20 as shown in FIG. At this time, since the adhesive force of the pressure-sensitive adhesive layer 31 is greater for the first process film 11 than for the second process film 12, the functional film 20 of the pressure-sensitive adhesive contacts. The portion 32 is left on the second step film 12 side in a state sandwiched between the second step film 12 and the functional film 20, and is not in contact with the functional film 20, that is, the first step. The part adhered to the film 11 is peeled off from the second process film 12 and transferred to the first process film 12 side.
[0016]
Thus, a laminate in which the pressure-sensitive adhesive layer 32 is provided with substantially the same width as the width b of the functional film 20, and the second process film 12 is bonded to the other surface of the pressure-sensitive adhesive layer 32. Is obtained.
[0017]
FIG. 2 is a schematic cross-sectional view showing an example in which transfer failure of the pressure-sensitive adhesive layer occurs when the first process film 11 is peeled off. When the adhesive force of the pressure-sensitive adhesive to the first process film 11 and the adhesive force to the second process film 12 are approximately the same, a part of the pressure-sensitive adhesive 32 remains in the second process film 12. As a result, a part of the pressure-sensitive adhesive 33 is transferred to the first process film 11 and the transfer becomes mottled. On the other hand, when the adhesive force of the pressure sensitive adhesive to the second process film 12 is greater than the adhesive force to the first process film 11, the first process film 11 is peeled from the functional film 20. Moreover, the pressure-sensitive adhesive layer 32 remains on the second process film 12 over almost the entire surface.
[0018]
In the present invention, the adhesive force of the pressure-sensitive adhesive layer 31 is made larger with respect to the first process film 11 than with respect to the second process film 12, but this difference in adhesive force is JIS K 6854- The 180 degree peeling adhesion strength by 2 is preferably 0.2 N / 25 mm or more.
[0019]
The material of the first process film 11 and the second process film 12 is not particularly limited, and various known resins can be used. For example, a polyolefin resin such as polyethylene or polypropylene, a polystyrene resin, a polyvinyl chloride resin, a polyvinyl acetate resin, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, a norbornene or a derivative containing a derivative thereof as a monomer. Synthesis of cyclic polyolefin resin such as coalescence, polycarbonate resin, polysulfone resin, polyethersulfone resin, polyarylate resin, polyvinyl alcohol resin, polyurethane resin, polyacrylate resin, polymethacrylate resin Polymers and natural polymers such as cellulose resins such as cellulose diacetate and cellulose triacetate can be used.
[0020]
The synthetic polymer may of course be a homopolymer of one kind of monomer, or may be a copolymer obtained by copolymerizing two or more kinds of monomers constituting each of the above resins. For example, an ethylene-vinyl alcohol copolymer that is a saponified product of an ethylene-vinyl acetate copolymer has a certain degree of adhesion to a normal resin, and therefore the first step for holding the functional film 20 The film 11 is preferable. A film having a multilayer structure composed of two or more kinds of polymers can also be used. A combination is selected from the above-mentioned various polymers so that the adhesive force of the pressure-sensitive adhesive layer 30 is greater for the first process film 11 than for the second process film 12.
[0021]
The first process film 11 and / or the second process film 12 may be subjected to a release treatment. The mold release process is a process for facilitating peeling when the adhesive is peeled off. In particular, the second process film 12 has substantially the same width as the functional film 20 as shown in FIG. Since it is held on one side of the pressure-sensitive adhesive layer 32 and then peeled off, a release treatment is applied to at least the surface of the second process film 12 on which the pressure-sensitive adhesive is laminated. It is preferable. The mold release treatment is generally performed by applying a mold release agent, and examples of the mold release agent include, but are not limited to, silicone resins, fluorine resins, and long-chain alkyl group-containing compounds. Of these, silicone-based release agents are generally used.
[0022]
The thickness of the first process film 11 and the second process film 12 may be about 20 to 200 μm, respectively.
[0023]
As the functional film 20, various films provided with an optical function can be used. The material is not particularly limited. For example, polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyvinyl chloride resins, polyvinyl acetate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, norbornene And cyclic polyolefin resins such as polymers having monomers as derivatives thereof, polycarbonate resins, polysulfone resins, polyether sulfone resins, polyarylate resins, polyvinyl alcohol resins, polyurethane resins, polyacrylate resins Synthetic polymers such as polymethacrylate resins and natural polymers such as cellulose resins such as cellulose diacetate and cellulose triacetate can be used. The synthetic polymer may of course be a homopolymer of one kind of monomer, or may be a copolymer obtained by copolymerizing two or more kinds of monomers constituting each of the above resins.
[0024]
The functional film 20 may be an ultraviolet curable resin or an electron beam curable resin. In this case, if the manufacturing method which hardens | cures after apply | coating a monomer to a base film is employ | adopted, a base film can also be made into the 1st process film 11 as it is.
[0025]
Examples of the functional film include a polarizing film and a retardation film. The polarizing film is obtained by, for example, aligning polyvinyl alcohol with iodine or a dichroic dye. Since polyvinyl alcohol is inferior in water resistance, it is preferably coated with a protective film, and cellulose triacetate is usually used for the protective film.
[0026]
The retardation film has a retardation (retardation) by stretching a resin film. For example, a polycarbonate resin, a polysulfone resin, a polyethersulfone resin, a polyarylate resin, a norbornene resin, and the like. Mainly used. A well-known method can be employ | adopted for extending | stretching, and longitudinal extending | stretching like extending | stretching between rolls and transverse extending | stretching like tenter extending | stretching are used a lot. Further, the stretching direction may be uniaxial stretching, but there are also those which have been oriented in the thickness direction in order to adjust the viewing angle when used in a liquid crystal display device. The retardation value of the retardation film is appropriately determined according to the desired characteristics, but generally a film having a range of 100 to 1,000 nm is often used. Moreover, it is one of the preferable forms to use a quarter wavelength film or a half wavelength film.
[0027]
The thickness of the functional film 20 varies depending on the type, but is generally in the range of about 20 to 200 μm.
[0028]
The pressure-sensitive adhesive 31 is a viscoelastic material that can be removed with almost no trace if it adheres to the surface of the adherend, if it adheres to the surface of another substance simply by pressing and peels it off the surface. It is also called an adhesive. Pressure-sensitive adhesives include acrylic, vinyl chloride, synthetic rubber, natural rubber, and silicone types. From these, transparent and optically isotropic A sex type can be selected and used. Among these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are one of the preferred resin bodies from the viewpoint of handling properties and durability.
[0029]
Acrylic pressure-sensitive adhesive is composed of a main monomer component having a low glass transition temperature that provides adhesion, a comonomer component having a high glass transition temperature that provides adhesion and cohesion, and a monomer component containing functional groups for improving crosslinking and adhesion. It is made of a copolymer mainly composed of Examples of the main monomer component include ethyl acrylate, butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, cyclohexyl acrylate, alkyl acrylates such as benzyl acrylate, butyl methacrylate, And methacrylic acid alkyl esters such as amyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. Examples of the comonomer component include methyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, styrene, acrylonitrile and the like. Furthermore, as functional group-containing monomer components, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, N -Hydroxyl group-containing monomers such as methylolacrylamide, acrylamide, methacrylamide, glycidyl methacrylate and the like.
[0030]
The pressure sensitive adhesive is preferably a crosslinked type. In this case, for example, various crosslinking agents such as an epoxy compound, an isocyanate compound, a metal chelate compound, a metal alkoxide, a metal salt, an amine compound, a hydrazine compound, and an aldehyde compound are used for crosslinking, and irradiation is performed. The method of making it bridge | crosslink can be applied, and these are suitably selected according to the kind of functional group. Furthermore, the weight average molecular weight of the main polymer constituting the pressure sensitive adhesive is preferably about 600,000 to 2,000,000, more preferably 800,000 to 1,800,000. When the weight average molecular weight is less than 600,000, the adhesiveness and durability of the adhesive to the adherend decrease when the amount of the plasticizer described later is large. In addition, when the weight average molecular weight exceeds 2 million, especially when the amount of plasticizer is small, the elasticity of the adhesive is increased and the flexibility is reduced, and the adherend generates contraction stress. Cannot be absorbed or relaxed.
[0031]
It is preferable to add a plasticizer to the pressure-sensitive adhesive. Examples of the plasticizer include phthalic acid esters, trimellitic acid esters, pyromellitic acid esters, adipic acid esters, sebacic acid esters, phosphoric acid triesters, glycol esters, process oils, liquid polyethers, A liquid polyterpene, other liquid resin, etc. are mentioned, One of these can be used individually or in mixture of 2 or more types. Furthermore, various additives such as an ultraviolet absorber, a light stabilizer, and an antioxidant can be added to the pressure-sensitive adhesive as necessary.
[0032]
The pressure-sensitive adhesive can be used by laminating two or more layers. When two or more layers are laminated, the same layer may be used or different layers may be used. The thickness of the pressure-sensitive adhesive layer 31 is usually about 10 to 50 μm, and when it is a laminate of two or more layers, it is preferable that the thickness is within this range as a whole.
[0033]
Moreover, the method of laminating the film for carrying out the present invention is not particularly limited, but press bonding, roll bonding, and the like can be employed. Generally, roll bonding is adopted as a preferred method because it is excellent in product uniformity and mass productivity.
[0034]
When supplying the laminated body of the 1st process film 11 and the functional film 20 and the laminated body of the 2nd process film 12 and the pressure sensitive adhesive layer 31 to a press bonding apparatus and a roll bonding apparatus, each The shape is not particularly limited. For example, when both are sheet-shaped, it becomes sheet-to-sheet bonding. Moreover, when one side is a sheet shape and the other is a roll shape, it becomes sheet-to-roll bonding. Furthermore, when both are roll shapes, it becomes roll-to-roll bonding. Generally, since roll-to-roll bonding is excellent in product uniformity and mass productivity, it is preferable that both have a roll shape.
[0035]
【Example】
Examples of the present invention are shown below, but the present invention is not limited to these examples.
[0036]
Example 1
In this example, the following materials were used.
Functional film: “Sumikalite SEF460510” (manufactured by Sumitomo Chemical Co., Ltd.), which is a uniaxially stretched retardation film made of polycarbonate and having a thickness of 60 μm.
First process film: “6221F” (product of Sekisui Chemical Co., Ltd.), which is a two-layer structure composed of polyethylene and an ethylene-vinyl alcohol copolymer and has a total thickness of 60 μm.
Second process film: a polyethylene terephthalate film having a thickness of 38 μm and having a release treatment on one side.
Pressure sensitive adhesive: “# 7 glue” (Lintech Co., Ltd.), which is an acrylate pressure sensitive adhesive. This pressure-sensitive adhesive “# 7 glue” has a 180 degree peeling adhesive strength (gripping speed of 300 mm / min) according to JIS K 6854-2 to the ethylene-vinyl alcohol copolymer surface of the first process film of 0. It was 42 N / 25 mm, and the same 180 degree peel-off adhesion strength with respect to the release-treated surface of the second process film was 0.08 N / 25 mm.
[0037]
At the center of the width direction on the ethylene-vinyl alcohol copolymer side of the first process film having a width of 40 cm and a length of 100 cm, the above-mentioned retardation film having a width of 10 cm and a length of 100 cm is laminated on a laminate made by Fuji Pla Co., Ltd. Machine). On the other hand, the pressure-sensitive adhesive “# 7 glue” was formed to a thickness of 25 μm on the entire surface of the release treatment surface of the second process film 30 cm wide × 100 cm long. Next, roll-to-roll bonding of the surface of the retardation film and the surface of the pressure-sensitive adhesive using the same “lami packer” as above so that the retardation film is in the center of the pressure-sensitive adhesive in the width direction. did. When the first process film is peeled off for this laminated product, two extra pressure-sensitive adhesives are transferred onto the first process film with a width of 10 cm and a length of 100 cm. A phase difference film was obtained. This is because the adhesive force of “# 7 glue” is higher on the first process film than on the second process film, so that an extra pressure-sensitive adhesive layer is selectively transferred to the first process film. This is because.
[0038]
Comparative Example 1
In Example 1, a film having a width of 50 cm and a length of 100 cm was used as the second process film, and the pressure sensitive adhesive “# 7 glue” was formed on the entire surface of one side, and laminated in the same manner as in Example 1. An attempt was made to make a product. In this case, the protruding adhesive was wound around the roll and the retardation film became unusable. This is because the width of the pressure sensitive adhesive was larger than the width of the first process film.
[0039]
Comparative Example 2
In Example 1, a film having a width of 5 cm and a length of 100 cm was used as the second process film, and the pressure sensitive adhesive “# 7 glue” was formed on the entire surface of one side, and laminated in the same manner as in Example 1. An article was made. About this laminated product, when the first process film was peeled off, only the first process film was peeled off. This laminate cannot use the entire width of the retardation film, and only the width where the pressure-sensitive adhesive is laminated can be used as the retardation film with a pressure-sensitive adhesive. This is because the width of the pressure sensitive adhesive was smaller than the width of the retardation film.
[0040]
Comparative Example 3
In Example 1, instead of the pressure sensitive adhesive “# 7 glue”, a laminated product was used in the same manner as in Example 1 except that an acrylate pressure sensitive adhesive “# 0 glue” (product of Lintec Corporation) was used. Was made. The "# 0 glue" used here has a 180 degree peeling adhesive strength (gripping speed of 300 mm / min) according to JIS K 6854-2 to the ethylene-vinyl alcohol copolymer surface of the first process film of 0.02 N / The same 180 degree peel-off adhesion strength with respect to the release-treated surface of the second process film was 0.09 N / 25 mm. When the first process film was peeled off from the obtained laminated product, only the first process film was peeled off, and the excess pressure-sensitive adhesive remained on the second process film. This is because the adhesive force of “# 0 glue” is greater on the second process film than on the first process film, so the extra pressure-sensitive adhesive layer was not transferred to the first process film. is there.
[0041]
The results of the above examples and comparative examples are summarized in Table 1.
[0042]
[Table 1]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Example No. Pressure-sensitive adhesive Pressure-sensitive adhesive width Operability Functional film availability ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ━━━━━
Example 1 # 7 glue 30cm Good 100%
───────────────────────────────────
Comparative Example 1 # 7 glue 50cm roll 0%
Comparative Example 2 # 7 paste 5cm good 50%
Comparative Example 3 # 0 glue 30cm Good No glue transferred ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
[0043]
【The invention's effect】
According to the present invention, a functional film in which a pressure-sensitive adhesive is laminated over the entire width of one side can be reliably produced with good operability.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing the method of the present invention step by step.
FIG. 2 is a schematic cross-sectional view showing an example in which a pressure-sensitive adhesive layer causes a transfer failure when the first process film is peeled off.
[Explanation of symbols]
11 …… First process film,
12 ... Second process film,
20: Functional film,
31-33 ... Pressure-sensitive adhesive layer.

Claims (3)

Laminating a functional film having a smaller width on the first process film;
Separately, a pressure sensitive adhesive layer is formed on the second process film, and the width of the pressure sensitive adhesive layer is not larger than the width of the second process film and larger than the width of the functional film. Not greater than the width of the first process film and the pressure sensitive adhesive has a greater adhesion to the first process film than to the second process film;
The functional film laminated on the first process film and the pressure-sensitive adhesive layer formed on the second process film are bonded together, and at this time, the exposed surface of the pressure-sensitive adhesive layer is the first. Pressing to contact the process film;
The first process film is peeled from the functional film,
A method for producing a functional film with a pressure-sensitive adhesive. The method according to claim 1, wherein the second step film is subjected to a release treatment on the surface on which the pressure-sensitive adhesive layer is formed. The method according to claim 1 or 2, wherein the functional film laminated on the first process film and the pressure-sensitive adhesive layer formed on the second process film are bonded by roll bonding. .

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