KR101837940B1 - Method for producing roll-body of surface-protective film for transparent conductive film - Google Patents

Abstract

It is an object of the present invention to provide a pressure-sensitive adhesive layer which maintains smoothness of the surface and has excellent handling property even when it is attached to a transparent conductive film, and improves defectiveness in appearance due to the surface protective film in the process of manufacturing and processing a transparent conductive film And a surface protective film for a transparent conductive film and a transparent conductive film using the same, which are excellent in productivity in the process of manufacturing a transparent electrode for a touch panel. A surface protective film (5) for a transparent conductive film which is used by being attached to the other surface of a transparent conductive film having a transparent conductive film formed on one side of a resin film, characterized in that an acrylic resin composition, using the acrylic pressure sensitive adhesive laminated pressure-sensitive adhesive layer (2) containing a cross-linking catalyst is a storage elastic modulus at 30 ℃ 4.0 × 10 ⁵ and Pa or more, the drying start after 15 minutes and 40 ℃ × 5 days in a pressure-sensitive adhesive layer PET after aging The adhesive strengths (a) and (b) to the film satisfy a relation of 0.9? A / b? 2.0.

Description

TECHNICAL FIELD [0001] The present invention relates to a surface protective film for a transparent conductive film,

The present invention relates to a surface protective film for a transparent conductive film to be used by being attached to the other surface of a transparent conductive film having a transparent conductive film formed on one side of a resin film, and a transparent conductive film using the same. More specifically, the present invention relates to a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed on a surface of a pressure-sensitive adhesive sheet, which has smoothness on the surface thereof and has excellent handling properties even when adhered to a transparent conductive film, And a good productivity in the process of manufacturing a transparent electrode for a touch panel, and a transparent conductive film using the same.

BACKGROUND ART [0002] Conventionally, a transparent conductive film (hereinafter sometimes simply referred to as a " conductive film ") has been known as a transparent conductive film in the technical fields of touch panels, electronic paper, electromagnetic wave shielding materials, various sensors, liquid crystal panels, organic EL, And is widely used for forming electrodes and the like. This transparent conductive film is formed by forming a transparent conductive film made of, for example, ITO (indium tin oxide compound), AZO or GZO (compound in which ZnO (zinc oxide) is added with aluminum or gallium) .

In the manufacturing process of the transparent electrode for a touch panel, a transparent conductive film having a transparent conductive film made of ITO, AZO, GZO, or the like is annealed, a crystallization process of a metal oxide film, a resist printing process, an etching process, A circuit forming process, an insulating layer printing process, a punching process, and the like. In the manufacturing process of such a transparent electrode, a surface protective film for a transparent conductive film is bonded and used in order to prevent damage or damage to the opposite side of the surface of the transparent conductive film on which the transparent conductive film is formed.

The protective film for a transparent conductive film is required to have heat resistance in that the annealing treatment, the formation of a wiring circuit by silver paste, and the like are performed at a temperature of about 150 캜 during the manufacturing process of the transparent electrode.

Various proposals have been made for a protective film for a transparent conductive film used in a manufacturing process of a transparent electrode such as a touch panel. For example, Patent Document 1 proposes a surface protective film for a transparent conductive film in which a pressure-sensitive adhesive layer is formed on one side of a substrate made of a thermoplastic resin film having a melting point of 200 ° C or higher. As compared with a surface protective film for a transparent conductive film using a polyolefin resin such as polyethylene or polypropylene as a base material.

Patent Document 2 discloses a surface protective film for a transparent conductive film which is applied on one side of a base film containing a polyethylene terephthalate resin and / or a polyethylene naphthalate resin and then dried at a predetermined temperature, residence time and tensile tension A method of producing a film has been proposed. The surface protective film for a transparent conductive film obtained by the above production method is not subjected to a large amount of curl even after being subjected to a heating step after being bonded to a transparent conductive film.

Patent Document 3 discloses a resin film in which a transparent conductive film is formed on one side of a resin film and a transparent conductive film having a protective film formed on the side of the resin film opposite to the side on which the transparent conductive film is formed and a protective film are formed, The coefficient of linear expansion in which the difference between the linear expansion coefficient of the first film having a heat shrinkage ratio of 0.5% or less in both the MD and TD directions after heating the film at 150 DEG C for 30 minutes and the resin film having the transparent conductive film and the protective film is 40 ppm / And the first film and the second film are formed in this order from the resin film. According to the present invention, it is possible to obtain a transparent conductive film having no dimensional change and curl due to heat treatment during a processing step such as a touch panel.

Patent Document 4 proposes a surface protective film for a transparent conductive film in which a surface of a pressure-sensitive adhesive layer of a surface protective film is smooth and defect defects in appearance are improved by using a release film having a predetermined thickness and a lubrication degree.

Japanese Patent Application Laid-Open No. 2003-170535 Japanese Patent Publication No. 4342775 Japanese Laid-Open Patent Publication No. 11-268168 Japanese Laid-Open Patent Publication No. 2013-226676

The present invention is to provide a surface protective film for a transparent conductive film, in which the pressure-sensitive adhesive layer of the surface protective film maintains the surface smoothness and defects in defects in appearance are improved, as in Patent Document 4. The surface protective film of Patent Document 4 is characterized by using a release film having a degree of polishing at 40 ° C of from 0.30 mN to 40 mN. However, the film having such a degree of stiffness has a problem in that the thickness becomes thick, there was. Further, when manufacturing the surface protective film or when using the surface protective film by the user, the winding diameter of the surface protective film may be restricted depending on the specification of the processing machine to be used. In this case, the surface protective film using a release film having a thick base material has a shorter winding length at a predetermined winding diameter than in a case where a release film having a thin base material is used, There was a falling problem.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a pressure-sensitive adhesive layer of a surface protective film for a transparent conductive film which maintains smoothness of the surface thereof while being rolled back from a roll, In the production and processing of a transparent conductive film, defective defects in appearance due to a surface protective film for a transparent conductive film are improved, and a surface for a transparent conductive film having a good productivity in the process of manufacturing a transparent electrode for a touch panel A protective film and a transparent conductive film using the same.

The surface protective film for a transparent conductive film is produced by applying a pressure-sensitive adhesive to a base film or a release film, evaporating the solvent in the pressure-sensitive adhesive by a drying process, and then peeling the release film or base film. As a result of intensive studies, the present inventors have found that there is a correlation between the cured state of the pressure-sensitive adhesive layer 15 minutes after the start of drying and the concavo-convex shape deformation on the surface of the pressure-sensitive adhesive layer. Also, by using the pressure-sensitive adhesive whose curing of the pressure-sensitive adhesive layer progresses within 15 minutes after the start of drying, even when a release film having a thin base thickness is used for adhesion of the pressure-sensitive adhesive layer of the surface protective film for a transparent conductive film, It is possible to suppress the occurrence of deformation of the unevenness on the surface to be adhered to the adherend, thereby completing the present invention.

In the process of producing a surface protective film, it is common to apply a pressure-sensitive adhesive on a base film and dry it to form a pressure-sensitive adhesive layer, and then cure in a roll state. During the curing period, Deformation occurs. Therefore, when the pressure-sensitive adhesive layer is cured after the release film is deformed, the surface shape of the release film is transferred to the surface of the pressure-sensitive adhesive layer, and when this is subjected to the production and processing steps of the transparent conductive film, It is becoming a cause of remarkable deterioration.

The present invention promotes the curing of the pressure-sensitive adhesive layer before the release film is deformed during the period of curing the surface protective film for a transparent conductive film in a roll form, thereby suppressing surface deformation of the pressure-sensitive adhesive layer even when the release film is deformed, It is a technical idea to keep it.

That is, in the period of curing the surface protective film for a transparent conductive film according to the present invention in a roll form, the curing of the pressure-sensitive adhesive layer is advanced before the pressure-sensitive adhesive layer to which the release film is adhered is deformed by the deformation of the release film, To prevent unevenness on the surface of the pressure-sensitive adhesive layer to be bonded to the pressure-sensitive adhesive layer, and to maintain smoothness.

The present inventors have found that the progress of curing of the pressure-sensitive adhesive layer can be grasped by comparing the adhesive strength of the pressure-sensitive adhesive layer after 15 minutes from the start of drying of the pressure-sensitive adhesive layer and after completing the aging (curing). More specifically, the ratio of the adhesive force of the pressure-sensitive adhesive layer to the PET film after 15 minutes of the start of drying of the pressure-sensitive adhesive layer and the completion of aging (curing) (the value obtained by dividing the pressure-sensitive adhesive force after 15 minutes from the start of drying by the pressure- It is possible to suppress the occurrence of deformation of the concavities and convexities on the surface to be adhered to the adherend of the pressure-sensitive adhesive layer even when a peeling film having a small thickness of the substrate is used for adhering the pressure-sensitive adhesive layer of the surface protective film for a transparent conductive film have.

In order to solve the above problems, the present invention provides the following surface protective film for a transparent conductive film.

1. A surface protective film for a transparent conductive film, which is used by being attached to the other surface of a transparent conductive film having a transparent conductive film formed on one side of a resin film, characterized in that an acrylic resin composition comprising an acrylic resin composition, a crosslinking agent and a crosslinking catalyst Wherein the pressure-sensitive adhesive layer has a storage elastic modulus at 30 DEG C of 4.0 x 10 < ⁵ > Pa or more and the pressure-sensitive adhesive layer after 15 minutes from the start of drying of the pressure- And the adhesive force of the pressure-sensitive adhesive layer to the PET film after aging at 40 DEG C for 5 days satisfies the following formula (1).

0.9? A / b? 2.0 (1)

(Where a is the adhesion of the pressure-sensitive adhesive layer to the PET film after 15 minutes from the start of drying of the pressure-sensitive adhesive layer and b is the adhesion of the pressure-sensitive adhesive layer to the PET film after aging at 40 ° C for 5 days).

In addition, the surface protective film for a transparent conductive film is provided with a transparent conductive film bonded to the other surface of a transparent conductive film having a transparent conductive film formed on one side of the resin film.

In the surface protective film for a transparent conductive film of the present invention, the pressure-sensitive adhesive layer formed in the state of being rewound from a roll retains the surface smoothness and has excellent handling even when it is attached to the transparent conductive film, A surface protective film for a transparent conductive film and a transparent conductive film using the surface protective film are excellent in productivity in a manufacturing process of a transparent electrode for a touch panel. .

In recent years, along with the thinning of the case of a high-performance portable terminal such as a smart phone, the thickness of the transparent conductive film to be used is progressing. The surface protective film for a transparent conductive film of the present invention has a very small curl that occurs even after a heating process in a state of being adhered to a thinned transparent conductive film in a manufacturing process of a transparent electrode for a touch panel. Thus, workability and production efficiency of the manufacturing process of the transparent electrode for a touch panel can be greatly improved.

1 is a cross-sectional view showing an example of a surface protective film for a transparent conductive film of the present invention.
2 is a cross-sectional view showing an example in which the surface protective film for a transparent conductive film of the present invention is applied to a transparent conductive film.
3 is a conceptual diagram showing an example of a method for producing a surface protective film for a transparent conductive film of the present invention.

Hereinafter, the present invention will be described in detail based on embodiments.

1 is a cross-sectional view showing an example of a surface protective film for a transparent conductive film of the present invention. In this surface protective film 5 for a transparent conductive film, a pressure-sensitive adhesive layer 2 is laminated on one surface of a transparent base material film 1 having flexibility. On the surface to be adhered to the adherend of the pressure-sensitive adhesive layer 2, the exfoliated release film 3 for protecting the surface of the pressure-sensitive adhesive layer is laminated via the exfoliated surface.

As the base film (1), a transparent flexible plastic film is used. Thus, the surface protective film for a transparent conductive film of the present invention can be subjected to a visual inspection of the conductive film while being bonded to the other surface of a transparent conductive film having a transparent conductive film formed on one surface thereof. The plastic film used as the base film (1) is preferably a polyester film such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and polybutylene terephthalate. In addition to the polyester film, plastic films of other resin types can be used as long as they have the required strength and optical suitability. The base film (1) is not particularly limited, such as a non-oriented film, a monoaxially or biaxially oriented film, and the like, but the heat shrinkage ratio of the base film is preferably low.

The thickness of the base film (1) of the surface protective film for a transparent conductive film according to the present invention is not particularly limited and may be selected according to the transparent conductive film to be used. When the thickness of the transparent conductive film to be used is as thick as 100 占 퐉 or more, the handling property of the transparent conductive film itself is not so bad, so that the surface protective film may be protected to protect the surface of the transparent conductive film. Therefore, the base film 1 of the surface protective film may have a thickness of about 25 to 75 mu m.

On the other hand, when the thickness of the transparent conductive film to be used is as thin as 50 m or less, the handling property of the transparent conductive film itself is poor. Therefore, it is preferable to use a thick substrate film in consideration of handling property. The thickness of the specific base film is preferably about 100 to 188 탆.

If necessary, an antioxidant layer, an antistatic layer, an oligomer-preventing layer, and an anti-scratch hard coat layer for preventing contamination of the surface are laminated on the opposite side of the surface of the base film 1 on which the pressure-sensitive adhesive layer 2 is laminated Or an easy adhesive treatment such as a corona discharge treatment or an anchor coat treatment may be carried out.

The pressure-sensitive adhesive layer (2) of the surface protective film for a transparent conductive film according to the present invention is preferably an acrylic pressure-sensitive adhesive. Particularly, a two-part type pressure-sensitive adhesive which blends an acrylic pressure-sensitive adhesive and a crosslinking agent immediately before use is preferable.

As the acrylic pressure-sensitive adhesive, a cross-linking agent is added to the (meth) acrylic polymer (acrylic resin composition), and if necessary, a pressure-sensitive adhesive to which a tackifier is added is preferable. The (meth) acrylic polymer is preferably a polymer obtained by copolymerizing a main monomer such as n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, etc. with acrylonitrile, vinyl acetate, methyl methacrylate, Of acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxybutyl acrylate, glycidyl methacrylate, N-methylol methacrylamide, and the like are generally copolymerized with a functional monomer such as acrylic acid, methacrylic acid, hydroxyethyl acrylate, The composition of the monomer constituting the (meth) acrylic polymer is preferably 50% or more of the (meth) acrylic monomer, and 100% of the (meth) acrylic monomer.

Examples of the crosslinking agent include an isocyanate compound, an epoxy compound, a melamine compound, and a metal chelate compound, among which an isocyanate compound is preferable. Further, a polyisocyanate compound having at least two or three or more isocyanate (NCO) groups in one molecule is preferable.

The polyisocyanate compound is classified into an aliphatic isocyanate, an aromatic isocyanate, a noncyclic isocyanate, and an alicyclic isocyanate, but any of them may be used. Specific examples of the bifunctional isocyanate compound include aliphatic isocyanate compounds such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and trimethylhexamethylene diisocyanate (TMDI), diphenylmethane diisocyanate (MDI ), Aromatic isocyanate compounds such as xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (H6XDI), dimethyldiphenylenediisocyanate (TOID), and tolylene diisocyanate (TDI).

Examples of the isocyanate compound having three or more functional groups include biuret-modified or isocyanurate-modified products of diisocyanates (compounds having two NCO groups in one molecule), tri- or higher-valent polyols such as trimethylolpropane (TMP) (A compound having at least three or more OH groups in the molecule).

The amount of the crosslinking agent to be added may be determined in consideration of the kind of the (meth) acryl-based polymer, the degree of polymerization, the amount of the functional group and the like, and is not particularly limited, but is generally about 0.5 to 10 parts by weight of the crosslinking agent relative to 100 parts by weight of the .

The surface protective film for a transparent conductive film according to the present invention is preferably a (meth) acrylic polymer and a cross-linking agent in that the curing of the pressure-sensitive adhesive layer needs to proceed before the release film is cured in the roll- In order to accelerate the crosslinking reaction, it is preferable to add a crosslinking catalyst. The crosslinking catalyst may be any substance that functions as a catalyst for the reaction (crosslinking reaction) of the (meth) acrylic polymer with the crosslinking agent. When the polyisocyanate compound is used as the crosslinking agent, an amine compound such as a tertiary amine, An organic lead compound, an organic zinc compound, and an organic iron compound.

Examples of tertiary amines include trialkylamines, N, N, N ', N'-tetraalkyldiamines, N, N-dialkylaminoalcohols, triethylenediamine, morpholine derivatives and piperazine derivatives .

Examples of the organic tin compound include dialkyltin oxide, dialkyltin fatty acid salt, and stannic acid tin salt.

The amount of the crosslinking catalyst to be added may be determined in consideration of the kind of the (meth) acrylic polymer, the degree of polymerization, the amount of the functional group, the kind of the crosslinking catalyst, the amount of the crosslinking catalyst and the like, and is not particularly limited. .

The crosslinking retarding agent may be contained as necessary in order to increase the viscosity of the pressure-sensitive adhesive composition after compounding the crosslinking agent or to prevent gelation and to increase the pot life of the pressure-sensitive adhesive composition.

Examples of the crosslinking retarder include? -Keto esters such as methyl acetoate, ethyl acetoate, octyl acetoate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoate; ketones such as acetylacetone, 2,4-hexanedione, And? -Diketone such as acetone. Particularly at least one selected from the group consisting of acetylacetone and ethyl acetoacetate. These are keto-enol tautomeric compounds. In a pressure-sensitive adhesive composition using a polyisocyanate compound as a cross-linking agent, blocking of the isocyanate group of the cross-linking agent inhibits excess viscosity increase or gelation of the pressure-sensitive adhesive composition after compounding of the cross- Port life can be extended.

The amount of the crosslinking retarder to be added is not particularly limited, but it is generally about 1.0 to 5.0 parts by weight based on 100 parts by weight of the (meth) acrylic polymer.

If necessary, a tackifier may be added to the tackifier. Examples of the tackifier include rosin, coumaroneindene, terpene, petroleum, and phenol.

The pressure-sensitive adhesive layer (2) of the surface protective film for a transparent conductive film according to the present invention may be mixed with an antistatic agent if necessary. As the antistatic agent, it is preferable that the (meth) acrylic polymer has good dispersion or compatibility. Examples of the antistatic agent that can be used include a surfactant system, an ionic liquid, an alkali metal salt, a metal oxide, a metal fine particle, a conductive polymer, carbon, and a carbon nanotube. A surfactant system, an ionic liquid, an alkali metal salt, and the like are preferable in terms of transparency and affinity for the (meth) acrylic polymer. The amount of the antistatic agent to be added to the pressure-sensitive adhesive can be appropriately determined in consideration of the kind of the antistatic agent and the compatibility with the base polymer. The type and amount of the antistatic agent are specifically set in consideration of the peeling electrification voltage required for peeling the surface protective film for a transparent conductive film according to the present invention from the transparent conductive film, the stain resistance of the adherend, and the adhesive strength .

The thickness of the pressure-sensitive adhesive layer (2) of the surface protective film for a transparent conductive film according to the present invention is not particularly limited, but is preferably 5 to 50 탆 or so, It is more preferable to make the thickness. If the thickness of the pressure-sensitive adhesive layer (2) exceeds 50 탆, the cost for producing the surface protective film for a transparent conductive film is increased, and therefore, the performance is poor. If the thickness of the pressure-sensitive adhesive layer 2 is less than 5 占 퐉, there is a problem that the adhesion to the transparent conductive film is lowered or the transparent conductive film is largely deformed when foreign substances are mixed when the surface protective film is applied to the transparent conductive film .

Further, the pressure-sensitive adhesive layer (2) of the surface protective film for a transparent conductive film according to the present invention has a peel strength of 0.05 to 0.5 N / 25 mm on the surface of the adherend, ) Pressure-sensitive adhesive layer. By providing such a surface protective film for a transparent conductive film having such an unfixed pressure-sensitive adhesive layer, it is possible to obtain excellent operability in that it can be easily peeled off from an adherend.

The material of the release film (3) of the surface protective film for a transparent conductive film according to the present invention is not particularly limited. As the material of the peelable film that can be used, a polyolefin film such as a polyethylene film, a polypropylene film, or a polymethylpentene film, or a peelable film obtained by peeling the surface of a film such as a polyester film using a peeling agent such as a silicon- , A fluororesin film, and a polyimide film. Alternatively, a plurality of films may be laminated using an adhesive, or laminated films may be laminated by melt-extruding a resin into a film. The single layer or laminated film is subjected to a peeling treatment using a peeling agent such as a silicon based peeling agent to obtain a peeling film.

Further, the thickness of the release film (3) of the surface protective film for a transparent conductive film according to the present invention is not particularly limited, and a thickness that is easy to use may be selected. Generally, the thickness is in the range of about 19 to 75 mu m.

When the release film 3 is made thick, the total length of the surface protective film for transparent conductive film in the roll having the same winding diameter wound in a roll shape is shortened. However, The appropriate thickness of the film is derived. The peeling film 3 is preferably a peeling film peeled off from a single-layer polyester film or a peeling film obtained by peeling a film obtained by laminating a polyester film with multiple layers using an adhesive.

The method of laminating the pressure-sensitive adhesive layer (2) and the release film (3) on the base film (1) in this order can be carried out by a known method and is not particularly limited. Specifically, there is a method in which the release film 3 is applied to the base film 1 after the pressure-sensitive adhesive layer 2 is coated and dried, a method in which the pressure-sensitive adhesive layer 2 is coated and dried on the release film 3, (1) may be bonded to each other.

Further, the pressure-sensitive adhesive layer can be formed on the base film 1 by a known method. Specifically, known coating methods such as a reverse coating method, a comma coating method, a gravure coating method, a slot die coating method, a Meyer bar coating method and an air knife coating method can be adopted.

The release film 3 may be peeled off by a known method. Specifically, a releasing agent is coated on one side of the releasing film 3 by a coating method such as a gravure coating method, a Meyer bar coating method or an air knife coating method, and the releasing agent is dried and cured by heating or ultraviolet irradiation . If necessary, the film to be peeled may be subjected to a pretreatment for improving adhesion to a film of a releasing agent such as a corona treatment, a plasma treatment or an anchor coat in advance.

2 is a schematic structural view showing an example of a laminated film 11 obtained by laminating a surface protective film for a transparent conductive film of the present invention onto a transparent conductive film.

The laminated film 11 is obtained by laminating the adhesive film 4 obtained by peeling the release film 3 from the surface protective film 5 for a transparent conductive film of the present invention by using the pressure sensitive adhesive layer 2 to form a transparent conductive film 10). ≪ / RTI > The transparent conductive film 10 is a transparent conductive film 7 formed on one surface 6a of the resin film 6. [ The adhesive film 4 is bonded to the other surface 6b of the resin film 6. [

Examples of the transparent conductive film 10 include a polyethylene terephthalate (PET) film in which a transparent conductive film such as ITO, AZO or GZO is formed, and a cyclic polyolefin film in which a transparent conductive film such as ITO, AZO or GZO is formed. Such a transparent conductive film is widely used for forming transparent electrodes and the like in the technical fields of touch panels, electronic paper, electromagnetic wave shielding materials, various sensors, liquid crystal panels, organic EL, solar cells and the like.

INDUSTRIAL APPLICABILITY The surface protective film for a transparent conductive film of the present invention can remarkably improve workability and production efficiency in the process of manufacturing a transparent electrode such as a touch panel and can reduce workability and handling property even in a thin transparent conductive film And exhibits excellent effects.

3 is a conceptual diagram showing an example of a method for producing a surface protective film for a transparent conductive film of the present invention.

The release film 3 and the base film 1 are released from the roll 21 on which the peeled release film 3 is wound and the roll 22 on which the base film 1 is wound. A pressure-sensitive adhesive is applied to one surface of the base film (1) by a pressure-sensitive adhesive application device (23). The base film 1 coated with the pressure-sensitive adhesive is dried in the drying furnace 24 to become the adhesive film 4. The surface of the adhesive film 4 on which the pressure-sensitive adhesive layer is formed is opposed to the exfoliated surface of the release film 3 and pressed against the pressure rolls 25 and 26 to obtain a surface protective film 5 for a transparent conductive film. The surface protective film (5) for the transparent conductive film is wound around the roll body (27). In general, the surface protective film 5 for a transparent conductive film is stored or transported in a state of a roll 27. [ The surface protective film 5 for a transparent conductive film is rewound from the roll body 27 when the film is bonded to the transparent conductive film 10.

Example

Next, the present invention will be described in detail based on examples.

(Production of surface protective film for transparent conductive film of Example 1)

One side of a biaxially stretched polyester film having a thickness of 25 占 퐉 was prepared by adding 1 part by weight of an addition reaction type silicone (manufactured by Toray Dow Corning, product name: SRX-211 to 100 parts by weight of platinum catalyst SRX-212 ) Was diluted with a mixed solvent of toluene and ethyl acetate 1: 1 to prepare a silicone film having a thickness of 0.1 mu m after being dried by a Meyer bar method. Further, the film was dried and cured in a hot-air circulating oven at 120 캜 for 1 minute to obtain a release film of Example 1.

The pressure-sensitive adhesive layer was prepared by blending an HDI crosslinking agent (Coronate HX manufactured by Nippon Polyurethane Industry Co., Ltd.) with 100 parts by weight of an acrylic polymer having a solid content of 40% copolymerized with 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate, And 0.03 part by weight of dibutyltin dilaurate as a crosslinking catalyst were added and mixed to form a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was applied on a polyethylene terephthalate film having a thickness of 125 탆 such that the thickness of the pressure-sensitive adhesive layer after drying was 20 탆, and the pressure-sensitive adhesive was dried in a hot air circulating oven at 130 캜 for 1 minute. Thereafter, the silicon-treated surface of the release film of Example 1 prepared above was laminated on the surface of the pressure-sensitive adhesive layer and laminated to obtain a surface protective film for a transparent conductive film of Example 1.

(Production of surface protective film for transparent conductive film of Example 2)

The surface protective film for a transparent conductive film of Example 2 was obtained in the same manner as in Example 1 except that the amount of the crosslinking agent added was changed to 6 parts by weight based on 100 parts by weight of the acrylic polymer.

(Production of surface protective film for transparent conductive film of Example 3)

The surface protective film for a transparent conductive film of Example 3 was obtained in the same manner as in Example 1 except that the amount of the crosslinking agent added was changed to 8 parts by weight based on 100 parts by weight of the acrylic polymer.

(Preparation of surface protective film for transparent conductive film of Comparative Example 1)

A surface protective film for a transparent conductive film of Comparative Example 1 was obtained in the same manner as in Example 1 except that the drying temperature of the pressure-sensitive adhesive layer was changed to 100 캜.

(Preparation of surface protective film for transparent conductive film of Comparative Example 2)

4 parts by weight of an epoxy cross-linking agent (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company) was added to 100 parts by weight of an acrylic polymer having a solid content of 40% copolymerized with butyl acrylate, 2-ethylhexyl acrylate and acrylic acid as a pressure- A surface protective film for a transparent conductive film of Comparative Example 2 was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive composition was added and mixed.

(Production of surface protective film for transparent conductive film of Comparative Example 3)

(Manufactured by NIPPON POLYURETHANE INDUSTRY CO., LTD.) Was added to 100 parts by weight of an acryl-based polymer having a solid content of 40% Coronate HX) as a cross-linking catalyst, and 0.03 part by weight of dibutyltin dilaurate as a crosslinking catalyst were added and mixed in the same manner as in Example 1 to obtain a surface protective film for a transparent conductive film of Comparative Example 3, .

(Preparation of surface protective film for transparent conductive film of Comparative Example 4)

A surface protective film for a transparent conductive film of Comparative Example 4 was obtained in the same manner as in Example 1 except that dibutyltin dilaurate as a crosslinking catalyst was not added.

Hereinafter, methods and test results of the evaluation test are shown. Here, the " hard-coated PET film " was used as an example of a base material (film) for a transparent conductive film.

(Measurement of storage elastic modulus)

With respect to the samples obtained in Examples and Comparative Examples, the storage elastic modulus at 30 캜 of the pressure-sensitive adhesive layer after curing for 5 days under the environment of 40 캜 was measured by a viscoelasticity measuring device (Reogel-E4000, manufactured by AVM Corporation).

(Measurement of Adhesion to PET Film)

For the samples obtained in Examples and Comparative Examples, the adhesive strength of the pressure-sensitive adhesive layer after 15 minutes from the start of drying of the pressure-sensitive adhesive layer and after curing for 5 days under the environment of 40 占 폚 was measured.

A sample is reciprocated and kneaded once with a 2 kg rubber roller on a biaxially oriented polyethylene terephthalate film (Dia Foil T100 manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 탆. When the PET film was peeled in a direction of 180 ° at a peeling rate of 300 mm / min using a small tabletop tester (EZ-L manufactured by Shimadzu Corporation) after leaving for 1 hour under an environment of 23 ° C. and 50% RH Were measured.

(Measurement of Initial Adhesion of Surface Protective Film for Transparent Conductive Film)

A hard coat-treated PET film (trade name: KB film # 50G01, product name: KB Film # 50G01) used for an ITO film subjected to a hard coat treatment on one side of a biaxially stretched polyester film having a thickness of 50 μm was used. A surface protective film for a transparent conductive film cut to a width of 25 mm was applied to the hard-coated surface of the PET film and stored for 1 hour under the conditions of 23 캜 and 50% RH to obtain a sample of initial adhesion . Thereafter, the strength when the surface protective film for a transparent conductive film was peeled off in the direction of 180 DEG at a peeling rate of 300 mm / min using a tensile tester was measured to obtain an initial adhesive force (N / 25 mm).

The measuring apparatus used was a compact benchtop test apparatus of type EZ-L manufactured by Shimadzu Corporation.

(Measurement of Adhesive Force after Heating of Surface Protective Film for Transparent Conductive Film)

A surface protective film for a transparent conductive film cut to a width of 25 mm was applied to the hard coated surface of the PET film and then stored for 1 hour in an environment at 150 캜 to measure a sticking force after heating. (N / 25 mm) after heating.

The measuring apparatus used was a compact benchtop test apparatus of type EZ-L manufactured by Shimadzu Corporation.

(A method for confirming the handling property when a surface protective film for a transparent conductive film is bonded to a hard coat-treated PET film)

The sample subjected to the appearance inspection of the surface protective film for a transparent conductive film was used as a surface protective film for the following transparent conductive film. A surface protective film for a transparent conductive film is applied to the hard-coated surface of a hard-coated PET film (product name: KB film # 50G01, manufactured by KYMOTO TOA Corporation), and then the laminate is cut into A4 size. Grab one corner of the four corners of the cut sample and swing back and forth twenty times before and after, as if floating in the air on the film side. Thereafter, it is visually confirmed whether the hard-coated PET film is folded or deformed. A hard coat-treated PET film was evaluated as having no folding or deformation (?), And having a folding or deformation as (X).

(Appearance inspection method of surface protective film for transparent conductive film)

A rolled product (400 mm wide x 100 m rolled up) of a surface protective film for a transparent conductive film is prepared in a test coater and kept in an oven at 40 캜 for 5 days to cure the adhesive. Thereafter, the appearance of the sample at a position 50 m from the end of the surface protective film for the transparent conductive film rewound from the rolled product (position substantially equal distance from both ends) is visually observed. (X) that the surface of the pressure-sensitive adhesive layer was smooth (?), That slight irregularities were generated on the surface of the pressure-sensitive adhesive layer (?), And that there was strong unevenness on the surface of the pressure-sensitive adhesive layer.

(Appearance inspection method of hard-coated film)

A sample subjected to a visual inspection of the surface protective film for a transparent conductive film was used as a surface protective film for the following transparent conductive film. A surface protective film for a transparent conductive film is applied to a hard coat treated surface of a hard coat treated PET film (product name: KB film # 50G01, manufactured by KYOTO CORPORATION), and then heat treatment is performed at 150 DEG C for 1 hour. After the surface protective film for a transparent conductive film is peeled off, the surface state of the hard-coated PET film is visually observed. The appearance of the hard coat-treated PET film was evaluated as smooth (O), the case where a slight deformation was generated in the concavo-convex shape (DELTA), and the case where a strong deformation was generated in the concavo-convex shape was evaluated as (X).

The measurement results for each sample are shown in Table 1. In Table 1, "Polymer A" is the acrylic polymer described in Example 1, "Polymer B" is the acrylic polymer described in Comparative Example 2, "Polymer C" is the acrylic polymer described in Comparative Example 3, "Crosslinking agent 1" is the HDI crosslinking agent described in Example 1 and Comparative Example 3, and "Crosslinking Agent 2" is the epoxy crosslinking agent described in Comparative Example 2. The value of the storage elastic modulus in Table 1 is expressed in a form in which a mantissa and an index are placed before and after E, for example, 4.0 x 10 < ⁵ >

From the measurement results shown in Table 1, the following can be found.

Quot; (a / b) of the adhesive force of the pressure-sensitive adhesive layer used in the surface protective film for a transparent conductive film in Examples 1 and 2 after 15 minutes of drying of the pressure-sensitive adhesive layer and after aging at 40 DEG C for 5 days, Is 1.4 to 1.6, the change of the adhesive force after 15 minutes of the start of drying and after completion of aging (curing) is small, and the surface irregularities of the pressure-sensitive adhesive layer are very small. The appearance of the hard-coated PET film using this surface protective film was good. In addition, handling properties when the surface protective film for transparent conductive film of Examples 1 and 2 were bonded to a hard coat-treated PET film were also excellent.

As for Example 3, the "ratio of the adhesive force to the PET film after 15 minutes of initiation of drying of the pressure-sensitive adhesive layer and after the completion of aging at 40 ° C for 5 days" (a / b) was 2.0. Compared with Examples 1 and 2, The unevenness of the surface of the layer was slightly increased, but the roughness of the surface of the pressure-sensitive adhesive layer was not transferred to the hard-coated PET film, and a hard-coated PET film having good appearance was obtained.

On the other hand, for Comparative Examples 1 and 2, "the ratio of the adhesive force to the PET film after 15 minutes of initiation of drying of the pressure-sensitive adhesive layer and after completion of aging at 40 ° C for 5 days" (a / b) was 2.3 to 8.5, The surface protective film had irregularities on the surface of the pressure-sensitive adhesive layer. Therefore, when the laminate laminated with the hard-coated PET film was heat-treated, the concave-convex shape of the surface of the pressure-sensitive adhesive layer was transferred to the hard-coated PET film, and the appearance of the hard-coated PET film deteriorated.

In Comparative Example 3, the storage modulus is 4.0 × 10 ⁵ small to be less than Pa, "the ratio of adhesion to the 15 minutes after start of drying of the pressure-sensitive adhesive layer and a PET film after 40 ℃ × 5 ilgan aging completion" of the pressure-sensitive adhesive layer (a / b) was 1.5. However, in the surface protective film for a transparent conductive film of Comparative Example 3, irregularities were generated on the surface of the pressure-sensitive adhesive layer. Therefore, when the laminate laminated with the hard-coated PET film was heat-treated, the concave-convex shape of the surface of the pressure-sensitive adhesive layer was transferred to the hard-coated PET film, and the appearance of the hard-coated PET film deteriorated.

In Comparative Example 4 in which the crosslinking catalyst was not added, the pressure-sensitive adhesive layer was cohesively broken in the evaluation of the adhesion of the pressure-sensitive adhesive layer to the PET film 15 minutes after the start of drying and the surface protective film for the transparent conductive film had unevenness on the surface of the pressure- Respectively. Therefore, when the laminate laminated with the hard-coated PET film was heat-treated, the concave-convex shape of the surface of the pressure-sensitive adhesive layer was transferred to the hard-coated PET film, and the appearance of the hard-coated PET film deteriorated.

The surface protective film for a transparent conductive film of the present invention has a very small curl that occurs even after a heating process in a state of being adhered to a thinned transparent conductive film in a manufacturing process of a transparent electrode for a touch panel. Thus, workability and production efficiency of the manufacturing process of the transparent electrode for a touch panel can be greatly improved. The surface protective film for a transparent conductive film of the present invention can be applied to a surface for manufacturing and processing a transparent conductive film used in technical fields such as a touch panel, an electronic paper, an electromagnetic wave shielding material, various sensors, a liquid crystal panel, an organic EL, It can be widely used as a protective film.

One… Base film, 2 ... Adhesive layer, 3 ... Peeling film, 4 ... Adhesive film, 5 ... Surface protective film for transparent conductive film, 6 ... Resin film, 6a ... One side of the resin film, 6b ... The other side of the resin film, 7 ... Transparent conductive film, 10 ... Transparent conductive film, 11 ... Laminated film, 21 ... The roll of the release film, 22 ... The roll of the base film, 23 ... Adhesive application device, 24 ... Drying, 25, 26 ... Squeeze roll, 27 ... A roll of a surface protective film for a transparent conductive film.

Claims (2)

A method for producing a roll of a surface protective film for a transparent conductive film, which is used by being attached to the other surface of a transparent conductive film having a transparent conductive film formed on one surface of a resin film,
An acrylic pressure sensitive adhesive composition comprising a (meth) acrylic polymer, a crosslinking agent and a crosslinking catalyst is applied to one side of a long substrate film wound and unwound from a roll of a base film to laminate the pressure sensitive adhesive layer, To form a crosslinked pressure-sensitive adhesive layer on the surface of the pressure-sensitive adhesive layer, and a long release film unwound and unwound from the roll of the release film is applied to the surface of the pressure-sensitive adhesive layer via the release agent layer of the release film, A long laminate is produced, and then the elongated laminate is wound to manufacture a roll of a surface protective film for a transparent conductive film,
Wherein the crosslinking agent is an isocyanate compound having three or more functional groups and is contained in an amount of 0.5 to 10 parts by weight of the crosslinking agent and 0.01 to 0.5 parts by weight of the crosslinking catalyst per 100 parts by weight of the (meth) acrylic polymer,
The pressure-sensitive adhesive layer and the storage modulus is 4.0 × 10 ⁵ Pa or more at 30 ℃ after aging 40 ℃ × 5 days, also, after the heat-drying and cross-linking initiated 15 minutes of the pressure-sensitive adhesive layer adhesion to the PET film of the pressure-sensitive adhesive layer and , And the crosslinking rate of the pressure-sensitive adhesive layer was heated and dried for 15 minutes so that the adhesive force of the pressure-sensitive adhesive layer to the PET film after aging at 40 DEG C for 5 days satisfied the following formula (1) Wherein the curing of the pressure-sensitive adhesive layer is advanced before the pressure-sensitive adhesive layer to which the release film is adhered is deformed by the deformation of the release film in the period of curing the pressure-
0.9? A / b? 2.0 (1)
(Where a is the adhesion of the pressure-sensitive adhesive layer to the PET film after 15 minutes from the start of drying of the pressure-sensitive adhesive layer and b is the adhesion of the pressure-sensitive adhesive layer to the PET film after aging at 40 ° C for 5 days). The method according to claim 1,
Wherein the release film is a release film having a release agent layer formed using a silicone-based release agent.

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