TWI617646B - Method for production antistatic surface protection film, and antistatic surface protection film - Google Patents

Abstract

The invention provides a method for manufacturing an antistatic surface protection film with less pollution to an adherend and no deterioration with time, and has excellent anti-peeling electrostatic performance, and an antistatic surface protection film. A method for manufacturing an antistatic surface protective film is to form an adhesive layer (2) on one side of a base film (1) made of a transparent resin, and then place the adhesive film on one side of the resin film (3). A release film (5) formed by laminating a release agent layer (4) containing an antistatic agent, and an antistatic surface protection bonded to the surface of the adhesive layer (2) by the release agent layer (4) A method for producing a film (10), wherein the release agent layer (4) comprises a release agent containing dimethylpolysiloxane as a main component, a polysiloxane compound that is liquid at 20 ° C, and antistatic Agent resin composition.

Description

Method for manufacturing antistatic surface protective film and antistatic surface protective film

The present invention relates to a method for producing an antistatic surface protective film and an antistatic surface bonded to the surface of an optical member (hereinafter, sometimes referred to as an "optical film") such as a polarizing plate, a retardation plate, and a lens film for a display Protective film. More specifically, the present invention provides a method for producing an antistatic surface protective film with less pollution to an adherend, no deterioration with time, and excellent anti-peeling electrostatic performance, and an antistatic surface protective film.

Currently, when manufacturing and transporting optical films such as polarizing plates, retardation plates, lens films for displays, anti-reflection films, hard coating films, transparent conductive films for touch panels, and optical products such as displays, The surface protection film is attached to the surface of the optical film to prevent surface contamination and scratches in subsequent steps. In order to save the labor and time of laminating the surface protective film and then attaching it to improve work efficiency, the appearance inspection of the optical film as a product may sometimes include a surface protective film laminated on the optical film. It is implemented directly in the state.

In the past, in order to prevent scratches and dirt during the manufacturing process of optical products For adhesion, a surface protection film having an adhesive layer provided on one side of a base film is generally used. The surface protective film is an adhesive layer that is bonded to the optical film with a slight adhesive force. The reason why the adhesive layer is set to have a microadhesive force is that when the used surface protective film is removed from the surface of the optical film and removed, it can be easily peeled off, and to prevent the adhesive from adhering and remaining on the substrate. Phenomenon on the optical film of the product of the adherend (so-called prevention of occurrence of adhesive residue).

In recent years, in the production process of a liquid crystal display panel, a peeling static voltage generated when a surface protective film attached to an optical film is peeled off and removed, destroying a driver IC or the like for controlling a display screen of a liquid crystal display panel. Circuit components and the orientation of liquid crystal molecules are damaged. Although these phenomena occur in a small number, they also occur.

In addition, in order to reduce the power consumption of the liquid crystal display panel, the driving voltage of the liquid crystal material tends to decrease, and the breakdown voltage of the driving IC also tends to decrease. Recently, it has been required to control the peeling static voltage within a range of +0.7 kV to -0.7 kV.

Therefore, in order to prevent defects caused by a high peeling static voltage when the surface protective film is peeled from an optical film as an adherend, a surface protective film has been proposed which uses an antistatic agent to reduce the peeling static voltage. Adhesive layer.

For example, Patent Document 1 discloses a surface protection film using an adhesive composed of an alkyltrimethylammonium salt, a hydroxyl-containing acrylic polymer, and a polyisocyanate.

In addition, Patent Document 2 discloses an adhesive composition composed of an ionic liquid and an acrylic polymer having an acid value of 1.0 or less, and an adhesive sheet using the composition.

In addition, Patent Document 3 discloses an acrylic polymer, a polymer An ether polyol compound, an adhesive composition composed of an alkali metal salt treated with an anion-adsorbing compound, and a surface protective film using the composition.

In addition, Patent Document 4 discloses an adhesive composition composed of an ionic liquid, an alkali metal salt, and a polymer having a glass transition temperature of 0 ° C. or lower, and a surface protective film using the composition.

In addition, Patent Documents 5 and 6 disclose the technical content of mixing a polyether-modified polysiloxane with an adhesive layer of a surface protective film.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1]: Japanese Patent Laid-Open No. 2005-131957

[Patent Document 2]: Japanese Patent Laid-Open No. 2005-330464

[Patent Document 3]: Japanese Patent Laid-Open No. 2005-314476

[Patent Document 4]: Japanese Patent Laid-Open No. 2006-152235

[Patent Document 5]: Japanese Patent Laid-Open No. 2009-275128

[Patent Document 6]: Japanese Patent No. 4537450

In the above Patent Documents 1 to 4, an antistatic agent is added inside the adhesive layer, but the thicker the thickness of the adhesive layer, the antistatic agent moves from the adhesive layer to the surface protective film over time. The more the attached adherend moves, the more it will move. In addition, in optical films such as LR (Low Reflective) polarizers and AG (Anti Glare) -LR polarizers, anti-fouling treatment is applied to the surface of the optical film by using a polysiloxane compound or fluoride. , When from When the surface protective film used for the optical film is peeled from the optical film to be an adherend, the peeling static voltage becomes high.

In addition, as described in Patent Documents 5 and 6, when the polyether-modified polysiloxane is mixed in the adhesive layer, it is difficult to fine-tune the adhesive force of the surface protective film. In addition, since the polyether-modified polysiloxane is mixed in the adhesive layer, when the conditions for coating and drying the adhesive composition on the substrate film are changed, the adhesion formed on the surface protective film is changed. The characteristics of the surface of the agent layer change subtly. In addition, from the viewpoint of protecting the surface of the optical film, the thickness of the adhesive layer cannot be set to be extremely thin. Therefore, according to the thickness of the adhesive layer, it is necessary to increase the amount of polyether-modified polysiloxane mixed in the adhesive layer. As a result, it is easy to contaminate the surface of the adherend, the adhesion force with time and the Pollution has changed.

In recent years, with the spread of 3D displays (stereoscopic displays), FPR (Film Patterned Retarder) films may be bonded to the surface of optical films such as polarizing plates. After peeling the surface protection film bonded to the surface of an optical film such as a polarizing plate, the FPR film is bonded. However, when the surface of an optical film such as a polarizing plate is contaminated with an adhesive or an antistatic agent used for a surface protective film, there is a problem that it is difficult to adhere the FPR film. Therefore, the surface protection film used for this application is required to have less contamination to an adherend.

On the other hand, in some liquid crystal panel manufacturers, as a method for evaluating the contamination property of a surface protection film to an adherend, the following method is used: the surface protection film bonded to an optical film such as a polarizing plate is peeled once After re-lamination in a state where air bubbles are mixed, the re-laminated article is heat-treated under prescribed conditions, and then the surface protective film is peeled off and the surface of the adherend is observed. In this evaluation method, even if the surface contamination of the adherend is trace If there is a difference in the contamination of the surface of the adherend between the portion where the bubbles are mixed and the portion where the adhesive of the surface protective film is in contact, it will remain as a bubble mark (also sometimes referred to as "bubble stain"). Therefore, as a method for evaluating the contamination of the surface of an adherend, it is a very strict evaluation method. In recent years, even as a result of determination by such a rigorous evaluation method, a surface protective film that has no problem with the surface contamination of an adherend is required. However, the current situation is that it has been difficult to solve this problem in a surface protection film using an adhesive layer containing an antistatic agent that has been proposed in the past.

Therefore, there is a need for a surface protection film for use in an optical film, which has very little contamination of the adherend and does not change the contamination of the adherend with time (it does not change over time). In addition, a surface protective film that suppresses the peeling static voltage when peeling from the adherend is low.

In order to solve this problem, the present inventors have conducted intensive studies.

In order to reduce contamination of the adherend and also to reduce the change with time of the antistatic performance, it is necessary to reduce the amount of the antistatic agent that is supposed to be the cause of contaminating the adherend. However, when the amount of the antistatic agent is reduced, the peeling static voltage when the surface protective film is peeled from the adherend becomes high. The present inventors have studied a method of suppressing the peeling static voltage when peeling a surface protective film from an adherend without increasing the absolute amount of an antistatic agent. As a result, it was found that instead of adding an antistatic agent to the adhesive composition and mixing to form an adhesive layer, the adhesive composition was coated and dried to laminate the adhesive layer, and then the adhesive was applied to the adhesive. The surface of the layer is provided with an appropriate amount of an antistatic agent component, which can suppress the peeling static voltage when peeling the surface protective film from the optical film as an adherend, and completed the present invention based on the above findings.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide an antistatic surface protection with excellent anti-peeling electrostatic properties with little pollution to adherends and no degradation with time (deterioration does not occur over time). A method for producing a film, and an antistatic surface protective film.

In order to solve the above-mentioned problem, the technical idea of the antistatic surface protection film of the present invention is that after applying the adhesive composition and drying to laminate the adhesive layer, the surface of the adhesive layer is given an appropriate amount at 20 ° C. The liquid silicone-based compound and the antistatic agent can suppress contamination of an adherend, and can suppress a peeling static voltage when peeled from an optical film as an adherend.

In order to solve the above-mentioned problems, the present invention provides a method for producing an antistatic surface protective film, which comprises forming an adhesive layer on one surface of a substrate film made of a transparent resin, and then placing the adhesive layer on one surface of the resin film. A method for producing an antistatic surface protective film in which a release agent layer containing a release agent layer is laminated, and the release agent layer is bonded to the surface of the adhesive layer, wherein the release agent layer comprises A resin composition containing methyl polysiloxane as a main component, a polysiloxane compound that is a liquid at 20 ° C., and an antistatic agent are formed.

The polysiloxane compound is preferably a polyether-modified polysiloxane.

The antistatic agent is preferably an alkali metal salt.

The adhesive layer is preferably an acrylic adhesive layer obtained by crosslinking a (meth) acrylate copolymer.

In addition, in order to solve the above-mentioned problems, the present invention provides an antistatic surface protective film formed by a transparent tree An adhesive layer is formed on one side of the base material film made of grease, and a release film in which a release agent layer containing an antistatic agent is laminated on one side of the resin film is bonded to the surface of the adhesive layer by the release agent layer. The release agent layer is formed of a resin composition containing a release agent containing dimethylpolysiloxane as a main component, a polysiloxane compound that is liquid at 20 ° C, and an antistatic agent.

The polysiloxane compound is preferably a polyether-modified polysiloxane.

The antistatic agent is preferably an alkali metal salt.

The adhesive layer is preferably an acrylic adhesive layer obtained by crosslinking a (meth) acrylate copolymer.

The present invention also provides an optical film to which the above-mentioned antistatic surface protective film is bonded.

In addition, the present invention provides an optical member to which the above-mentioned antistatic surface protective film is bonded.

The antistatic surface protection film of the present invention has less pollution to the adherend, and has no time-varying change to the adherend's low pollution (it will not change with time). In addition, based on the present invention, it is possible to provide a method for producing an antistatic surface protective film and an antistatic surface protective film, in which the surface of an adherend such as an LR polarizing plate or an AG-LR polarizing plate is made of polysiloxane Compounds, fluorides, and other optical films that have undergone antifouling treatment. This antistatic surface protective film also suppresses the peeling static voltage that occurs when the antistatic surface protective film is peeled from the adherend, and it has excellent deterioration over time. Anti-peeling electrostatic performance.

The antistatic surface protection film according to the present invention can reliably protect optical The surface of the film can therefore improve productivity and yield.

1‧‧‧ substrate film

2‧‧‧adhesive layer

3‧‧‧ resin film

4‧‧‧ peeling agent layer

5‧‧‧ peeling film

Polysiloxanes and antistatic agents that are liquid at 7‧‧‧20 ° C

8‧‧‧ Adhered body (optical member)

10‧‧‧Anti-static surface protective film

11‧‧‧ Anti-static surface protective film with peeling film

20‧‧‧ Optical member with anti-static surface protective film

FIG. 1 is a cross-sectional view showing the concept of an antistatic surface protection film of the present invention.

2 is a cross-sectional view showing a state where a release film is peeled from the antistatic surface protective film of the present invention.

FIG. 3 is a cross-sectional view showing an embodiment of the optical member of the present invention.

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

FIG. 1 is a cross-sectional view showing the concept of an antistatic surface protection film of the present invention. In this antistatic surface protection film 10, an adhesive layer 2 is formed on the surface of one side of a transparent base film 1. A release film 5 is laminated on the surface of the adhesive layer 2, and the release film 5 is formed by forming a release agent layer 4 on the surface of the resin film 3.

As the base film 1 used in the antistatic surface protection film 10 of the present invention, a base film made of a resin having transparency and flexibility is used. Thereby, the appearance inspection of an optical member can be performed in the state which bonded the antistatic surface protective film to the optical member as an adherend. As the film made of a transparent resin used as the base film 1, polyethylene terephthalate, polyethylene naphthalate, and polyethylene isophthalate ( Polyester films such as polyethylene isophthalate) and polybutylene terephthalate. The film may have a desired strength and optical compatibility, and a film made of another resin may be used in addition to the polyester film. The base film 1 may be an unstretched film or a film obtained by uniaxial stretching or biaxial stretching. In addition, the stretching ratio of the stretched film and the axial direction formed by the crystallization of the stretched film may be selected. The direction angle is controlled at a specific value.

The thickness of the base film 1 used in the antistatic surface protection film 10 of the present invention is not particularly limited, for example, a thickness of about 12 to 100 μm is preferred; if the thickness is about 20 to 50 μm, it is easy to handle And therefore better.

In addition, if necessary, an antifouling layer, an antistatic layer, and a hard coating layer to prevent surface contamination can be provided on the surface of the base film 1 opposite to the surface on which the adhesive layer 2 is formed. Wait. In addition, the surface of the base film 1 may be subjected to adhesion treatment such as surface modification by corona discharge, application of a primer, and the like.

In addition, as for the adhesive layer 2 used in the antistatic surface protection film 10 of the present invention, as long as it is adhered to the surface of the adherend, it can be easily peeled off after use and it is difficult to contaminate the adherend. The adhesive layer is not particularly limited, but in consideration of durability after bonding to an optical film, an acrylic adhesive layer obtained by crosslinking a (meth) acrylate copolymer is generally used. .

Examples of the (meth) acrylate copolymer include a copolymer obtained by copolymerizing a main monomer with a comonomer and a functional monomer. Among these, the main monomer includes n-butyl acrylate and acrylic acid. 2-ethylhexyl, isooctyl acrylate, isononyl acrylate, etc .; the comonomers include acrylonitrile, vinyl acetate, methyl methacrylate, ethyl acrylate, etc .; the functional monomer may be Examples include acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxybutyl acrylate, glycidyl methacrylate, and N-methylolmethacrylamide. In the (meth) acrylic acid ester copolymer, both the main monomer and the comonomer may be (meth) acrylic acid esters, and may contain one or two or more kinds of comonomers other than (meth) acrylic acid esters. Monomer.

In addition, the (meth) acrylate copolymer may be copolymerized or mixed with a polyoxyalkylene-containing compound. Examples of the copolymerizable polyoxyalkylene-containing compound include polyethylene glycol (400) monoacrylate, polyethylene glycol (400) monomethacrylate, and methoxypolyethylene glycol (400 ) Acrylate, methoxy polyethylene glycol (400) methacrylate, polypropylene glycol (400) monoacrylate, polypropylene glycol (400) monomethacrylate, methoxy polypropylene glycol (400) acrylate, Methoxy polypropylene glycol (400) methacrylate and the like. By copolymerizing these polyoxyalkylene-containing monomers with the main monomer and functional monomer of the (meth) acrylic acid ester copolymer, it is possible to obtain a polymer composed of a polyoxyalkylene-containing copolymer. Adhesive.

The polyoxyalkylene-containing compound that can be mixed with the (meth) acrylate copolymer is preferably a (meth) acrylate copolymer containing a polyoxyalkylene, and more preferably a polyoxyalkylene. Examples of polymers of (meth) acrylic monomers such as polyethylene glycol (400) monoacrylate, polyethylene glycol (400) monomethacrylate, and methoxypolyethylene glycol (400) Acrylate, methoxypolyethylene glycol (400) methacrylate, polypropylene glycol (400) monoacrylate, polypropylene glycol (400) monomethacrylate, methoxypolypropylene glycol (400) acrylic acid Polymers such as esters and methoxy polypropylene glycol (400) methacrylate. By mixing these polyoxyalkylene-containing compounds with the (meth) acrylate copolymer, an adhesive to which a polyoxyalkylene-containing compound is added can be obtained.

Examples of the curing agent added to the adhesive layer 2 include a isocyanate compound, an epoxy compound, a melamine compound, and a metal chelate as a crosslinking agent for crosslinking the (meth) acrylate copolymer. . Examples of the thickener include rosin, coumarone-indene, terpene, petroleum, and phenol.

The thickness of the adhesive layer 2 used in the antistatic surface protection film 10 of the present invention is not particularly limited. For example, a thickness of about 5 to 40 μm is preferred, and a thickness of about 10 to 30 μm is more preferred. When the peeling strength (adhesive force) of the antistatic surface protective film to the surface of the adherend is about 0.03 to 0.3N / 25mm and the adhesive layer 2 has a slight adhesive force, the antistatic surface is peeled from the adherend. The protective film is preferable because it has excellent operability. In addition, from the viewpoint of excellent operability when peeling the release film 5 from the antistatic surface protective film 10, it is preferable that the peel force of the peeling film 5 from the adhesive layer 2 is 0.2 N / 50 mm or less.

In addition, in the release film 5 used in the antistatic surface protection film 10 of the present invention, a release agent layer 4 is formed on one side of the resin film 3, and the release agent layer 4 contains Oxyalkane is a resin composition containing a release agent as a main component, a polysiloxane compound that is liquid at 20 ° C, and an antistatic agent.

Examples of the resin film 3 include a polyester film, a polyimide film, a polyethylene film, a polypropylene film, and a polyimide film. From the viewpoint of excellent transparency or relatively low cost, polyester is particularly preferred. membrane. The resin film may be an unstretched film, or a uniaxially stretched film or a biaxially stretched film. The stretching ratio of the stretched film and the orientation angle in the axial direction of the stretched film accompanying crystallization may be controlled to specific values.

The thickness of the resin film 3 is not particularly limited, and for example, a thickness of about 12 to 100 μm is preferable; a thickness of about 20 to 50 μm is easy to handle, so it is more preferable.

In addition, the surface of the resin film 3 may be subjected to corona-based treatment as necessary. Adhesive treatments such as surface modification by discharge and application of primer.

Examples of the release agent comprising dimethylpolysiloxane as the main component constituting the release agent layer 4 include well-known polysiloxanes such as addition reaction type, condensation reaction type, cation polymerization type, and radical polymerization type. Alkane release agent. Examples of commercially available products of the addition reaction type polysiloxane-based stripping agent include KS-776A, KS-847T, KS-779H, KS-837, KS-778, and KS-830 (Shin-Etsu Chemical Industry Co., Ltd. (Manufactured by the company); SRX-211, SRX-345, SRX-357, SD7333, SD7220, SD7223, LTC-300B, LTC-350G, LTC-310 (Dow Corning Toray (Stock) Company (Dow Corning Toray Co., Ltd.)). As a condensation reaction type commercially available product, SRX-290, SYLOFF-23 (made by Dow Corning Toray Co., Ltd.), etc. are mentioned, for example. Examples of commercially available cationic polymerization products include TPR-66501, TPR-6500, UV9300, UV9315, and UV9430 (manufactured by Momentive Performance Materials Inc.), X62-7622 (Shin-Etsu Chemical Industry Co., Ltd.) (Stock) company)). As a commercially available product of a radical polymerization type, X62-7205 (made by Shin-Etsu Chemical Industry Co., Ltd.) etc. are mentioned, for example.

Examples of the polysiloxane compound constituting the release agent layer 4 that is liquid at 20 ° C. include polyether-modified polysiloxane, alkyl-modified polysiloxane, and methanol higher fatty acid ester-modified polysiloxane. Siloxane, etc. In the present invention, in order to improve the antistatic property of the surface of the adhesive layer, a polysiloxane which is liquid at 20 ° C. in a state compatible with the release agent layer containing dimethylpolysiloxane as a main component is used. Compound. From the uses of the present invention, polyether-modified polysiloxanes among modified polysiloxane compounds are preferred. The polyether chain in the polyether-modified polysiloxane is composed of ethylene oxide (ethylene oxide), propylene oxide (propylene oxide), and the like, for example, by By selecting the molecular weight of the polyethylene oxide used in the side chain, physical properties such as compatibility with the polysiloxane release agent and antistatic effect can be adjusted.

Examples of commercially available products of polyether-modified polysiloxane include KF-351A, KF-352A, KF-353, KF-354L, KF-355A, and KF-642 (Shin-Etsu Chemical Industry ( Stock)); SH8400, SH8700, SF8410 (made by Dow Corning Toray Co., Ltd.); TSF-4440, TSF-44441, TSF-4445, TSF-4446, TSF-4450 (Made by Momentive Performance Materials Inc.); BYK-300, BYK-306, BYK-307, BYK-320, BYK-325, BYK-330 (by BYK-Chemie) and the like.

The amount of polysiloxane compounds that are liquid at 20 ° C relative to the release agent containing dimethylpolysiloxane as the main component depends on the type of the polysiloxane compound and the degree of compatibility with the release agent. The difference is different, as long as it is set in consideration of the peeling static voltage required when peeling the antistatic surface protective film from the adherend, the contamination property to the adherend, the adhesion characteristics, and the like.

The antistatic agent constituting the release agent layer 4 is preferably one having good dispersibility to a release agent solution containing dimethylpolysiloxane as a main component and not hindering a solution containing dimethylpolysiloxane as a main component. A hardened antistatic agent for release agents. As such an antistatic agent, an alkali metal salt is preferable.

The alkali metal salt may include: comprising lithium, sodium, potassium salts, specifically, for example, is preferably used by containing Li ^+, Na ^+, K ⁺ cations comprising Cl ^-, Br ^{-, _{I -, BF 4 -, PF}} 6 -, SCN -, ClO 4 -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, (CF 3 SO _{2) 3} C ^- anions consisting of a metal salt. Among them, LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li are particularly preferably used. (CF ₃ SO ₂ ) ₃ C and other lithium salts. These alkali metal salts may be used alone or in combination of two or more. To stabilize the ionic substance, a compound containing a polyoxyalkylene (polyethylene glycol) structure may be added.

The amount of antistatic agent added to the release agent containing dimethylpolysiloxane as the main component varies depending on the type of the antistatic agent and the degree of affinity with the release agent, but it is considered that The peeling static voltage required for peeling the antistatic surface protection film on the body, the contamination property of the adherend, the adhesion characteristics, and the like may be set.

There is no particular limitation on the method of mixing the release agent containing dimethylpolysiloxane as a main component, the polyether-modified polysiloxane, and the antistatic agent. Any one of the following mixing methods can be adopted: in a release agent containing dimethylpolysiloxane as a main component, after adding polyether-modified polysiloxane and an antistatic agent to mix, add a release agent for hardening A method of mixing catalysts; using an organic solvent to dilute a stripping agent containing dimethylpolysiloxane as a main component in advance, adding and mixing a polyether-modified polysiloxane and an antistatic agent and a curing agent for the stripping agent and mixing them A method of diluting a release agent containing polysiloxane as a main component in an organic solvent in advance, adding a catalyst and mixing, and then adding and mixing a polyether-modified polysiloxane and an antistatic agent. In addition, if necessary, materials such as an adhesion promoter such as a silane coupling agent, or a compound containing a polyoxyalkylene group to assist the antistatic effect may be added.

There is no particular limitation on the mixing ratio of the release agent containing dimethyl polysiloxane as the main component, the polyether-modified polysiloxane, and the antistatic agent, but it is relatively The solid component 100 of the release agent with alkane as the main component is preferably a polyether-modified polysiloxane and an antistatic agent. 5 to 100 ratio. Relative to the solid content 100 of the release agent containing dimethylpolysiloxane as the main component, if the polyether modified polysiloxane and the antistatic agent are added in a proportion of less than 5 in terms of solid content, antistatic The transfer amount of the adhesive to the surface of the adhesive layer is also reduced, making it difficult for the adhesive layer to exert an antistatic function. In addition, with respect to the solid content 100 of the release agent containing dimethylpolysiloxane as a main component, if the polyether-modified polysiloxane and the antistatic agent are added in an amount exceeding 100% in terms of solid content, then As a result, the release agent containing dimethylpolysiloxane as the main component together with the polyether-modified polysiloxane and the antistatic agent will also be transferred to the surface of the adhesive layer, so the adhesive layer may be reduced. Adhesive properties.

In the present invention, the method for forming the adhesive layer 2 on the base film 1 of the antistatic surface protection film 10 and the method for bonding the release film 5 can be performed by a known method, and are not particularly limited. Specifically, (1) the resin composition for forming the adhesive layer 2 is coated on one side of the base film 1 and dried to form an adhesive layer and then the release film 5 is bonded; Method; (2) a method of applying the resin composition for forming the adhesive layer 2 on the surface of the release film 5 and drying to form an adhesive layer, and then bonding the base film 1 and the like. Either method can be used.

When the adhesive layer 2 is formed on the surface of the base film 1, a known method can be used. Specifically, well-known coating methods, such as reverse coating, notch wheel blade coating, gravure coating, slit extrusion coating, Mayer bar coating, and air knife coating, can be used.

Similarly, when the release agent layer 4 is formed on the resin film 3, it can be performed by a well-known method. Specifically, well-known coating methods, such as gravure coating, Mylar bar coating, and air knife coating, can be used.

In the antistatic surface protective film 10 of the present invention having the above-mentioned configuration, the surface potential when peeled from the optical film as an adherend is preferably +0.7 kV to -0.7 kV. The surface potential is more preferably +0.5 kV to -0.5 kV, and the surface potential is more preferably +0.1 kV to -0.1 kV. This surface potential can be adjusted by changing the type and amount of polyether-modified polysiloxane and antistatic agent contained in the release agent layer.

FIG. 2 is a cross-sectional view showing a state where a release film is peeled from the antistatic surface protection film of the present invention.

By peeling the release film 5 from the antistatic surface protective film 10 shown in FIG. 1, the polysiloxane compound and the antistatic liquid contained in the release agent layer 4 of the release film 5 at 20 ° C. are liquid. A part of the adhesive (reference numeral 7) is transferred (attached) to the surface of the adhesive layer 2 of the antistatic surface protection film 10. Therefore, in FIG. 2, the spots of reference numeral 7 schematically show the polysiloxane compound and the polysiloxane compound that are liquid at 20 ° C. and are transferred to the surface of the adhesive layer 2 of the antistatic surface protection film. Antistatic agent.

In the antistatic surface protection film of the present invention, when the antistatic surface protection film 11 in a state where the release film is peeled off as shown in FIG. 2 is attached to the adherend, it is transferred to the adhesive layer 2 Surface polysiloxane compounds and antistatic agents that are liquid at 20 ° C come into contact with the surface of the adherend. With this operation, it is possible to suppress the peeling static voltage when the antistatic surface protective film is peeled from the adherend again.

FIG. 3 is a cross-sectional view showing an embodiment of an optical member of the present invention.

In a state where the release film 5 is peeled from the antistatic surface protection film 10 of the present invention and the adhesive layer 2 is exposed, the adhesive layer 2 is attached to the substrate as a substrate. On the optical member 8 of the adherend.

That is, FIG. 3 shows the optical member 20 to which the antistatic surface protective film 10 of the present invention is bonded. Examples of the optical member include optical films such as a polarizing plate, a retardation plate, a lens film, a polarizing plate also serving as a retardation plate, and a polarizing plate also serving as a lens film. Such an optical member is used as a constituent member of a liquid crystal display device such as a liquid crystal display panel, various optical systems such as various measuring instruments, and the like. Examples of the optical member include optical films such as antireflection films, hard coat films, and transparent conductive films for touch panels. In particular, it can be suitably used as a low-reflection-treated polarizing plate (LR polarizing plate) and an anti-glare low-reflection polarizing plate (AG) bonded to a surface that has been subjected to anti-pollution treatment with a polysiloxane compound, fluorine compound, or the like. -LR polarizer) Anti-static surface protective film on the surface of the optical film such as anti-pollution treatment.

According to the optical member of the present invention, when the antistatic surface protective film 10 is peeled off from the optical member (optical film) as an adherend, the peeling static voltage can be sufficiently suppressed to a low level, so there is no need to worry about Destroying circuit components such as a driving IC, a TFT element, and a gate line driving circuit can improve the production efficiency in the steps of manufacturing a liquid crystal display panel and the like, and ensure the reliability of the production steps.

[Example]

The present invention is further explained by the following examples.

(Example 1)

(Manufacture of antistatic surface protective film)

5 parts by weight of an addition reaction type polysiloxane (product name: SRX-345, manufactured by Dow Corning Toray Co., Ltd.) and 0.15 parts by weight of polyether modified Polysiloxane (Product name: SH8400, manufactured by Dow Corning Toray Co., Ltd.), 5 parts by weight of lithium perchlorate, 10% vinegar Acid ethyl ester solution, 95 parts by weight of toluene and ethyl acetate mixed solvent of 1: 1, and 0.05 parts by weight of a platinum catalyst (product name is SRX-212 Catalyst), Dow Corning Toray Co., Ltd. (Manufactured) were mixed together and stirred to prepare a coating material for forming the release agent layer of Example 1. Using a Müller rod, the coating material forming the release agent layer of Example 1 was applied on the surface of a polyethylene terephthalate film having a thickness of 38 μm so that the thickness after drying was 0.2 μm. It dried at 120 degreeC for 1 minute in the hot-air circulation type oven, and obtained the peeling film of Example 1. On the other hand, 30 parts by weight of an acrylate copolymer having a weight average molecular weight of 470,000, which was copolymerized with 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate at a weight ratio of 100: 4, was dissolved in 70 An adhesive (a 30% ethyl acetate solution having a solid content of 30% by weight) was added to ethyl acetate, and 1.2 parts by weight of an HDI-based hardener (product name: Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.) was mixed to form an application liquid, and the application liquid was applied to a thickness of 38 μm so that the thickness after drying was 20 μm. The surface of the polyethylene terephthalate film was dried in a hot air circulation oven at 100 ° C. for 2 minutes, thereby forming an adhesive layer. Then, on the surface of the adhesive layer, a release agent layer (polysiloxane-treated surface) of the release film of Example 1 produced as described above was bonded. The obtained adhesive film was held in an environment at 40 ° C. for 5 days to harden the adhesive, and the antistatic surface protection film of Example 1 was obtained.

(Example 2)

An Example was obtained in the same manner as in Example 1 except that the thickness after drying of the coating material forming the release agent layer of Example 1 was set to 0.1 μm. 2 Anti-static surface protective film.

(Example 3)

As the addition reaction type polysiloxane of Example 1, a product named SRX-211 manufactured by Dow Corning Toray Co., Ltd. was used as a polyether-modified polysiloxane Siloxane uses a product named KS-352A manufactured by Shin-Etsu Chemical Industry Co., Ltd., and uses 10 parts by weight of a lithium bis (trifluoromethanesulfonium) imide solution in 10% ethyl acetate instead of 5 weight. Parts of lithium perchlorate was a 10% ethyl acetate solution. Except for the above, the same operation as in Example 1 was performed to obtain an antistatic surface protection film of Example 3.

(Comparative example 1)

5 parts by weight of an addition reaction type polysiloxane (product name is SRX-345, manufactured by Dow Corning Toray Co., Ltd.), 95 parts by weight of a mixed solvent of toluene and ethyl acetate of 1: 1, And 0.05 parts by weight of a platinum catalyst (product name: SRX-212 Catalyst, manufactured by Dow Corning Toray Co., Ltd.) were mixed together and mixed by stirring to prepare a coating material for forming a release agent layer of Comparative Example 1. Using a Mettler rod, the coating material forming the release agent layer of Comparative Example 1 was coated on the surface of a polyethylene terephthalate film having a thickness of 38 μm so that the thickness after drying was 0.2 μm, and It dried in the hot-air circulation type oven at 120 degreeC for 1 minute, and the peeling film of the comparative example 1 was obtained. On the other hand, 0.3 parts by weight of a polyether-modified polysiloxane (product name) was added to and mixed with 100 parts by weight of the adhesive of Example 1 (ethyl acetate solution having a solid content of 30%). SH8400, manufactured by Dow Corning Toray Co., Ltd., 10 parts by weight of lithium perchlorate, 10% ethyl acetate solution, and 1.2 parts by weight of HDI-based hardener (Product name is Coronate HX, Japan Polyurethane Industrial Co., Ltd.) to form an application liquid, and apply the application liquid to a thickness of 20 μm after drying on a surface of a polyethylene terephthalate film having a thickness of 38 μm, and then apply 100 The hot air circulation oven at ℃ was dried for 2 minutes, thereby forming an adhesive layer. Then, on the surface of the adhesive layer, a release agent layer (polysiloxane-treated surface) of the release film of Comparative Example 1 produced as described above was bonded. The obtained adhesive film was held in an environment at 40 ° C. for 5 days to harden the adhesive, and an antistatic surface protective film of Comparative Example 1 was obtained.

(Comparative example 2)

In addition to setting polyether-modified polysiloxane (product name: SH8400, manufactured by Dow Corning Toray Co., Ltd.) to 0.03 parts by weight, and 10% ethyl acetate solution of lithium perchlorate to 1 weight Other operations were performed in the same manner as in Comparative Example 1, and an antistatic surface protective film of Comparative Example 2 was obtained.

(Example 4)

30 parts by weight of an acrylate copolymer having a weight average molecular weight of 480,000 obtained by copolymerizing 2-ethylhexyl acrylate, butyl acrylate, and 2-hydroxyethyl acrylate at a weight ratio of 60: 40: 4, was dissolved in An adhesive (70% ethyl acetate solution with a solid content of 30%) is formed in 70 parts by weight of ethyl acetate, and 1.2 parts by weight of HDI-based hardener (product name is added and mixed with 100 parts by weight of the adhesive). Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.) was used to obtain an application liquid, and this application liquid was used in place of the application liquid of Example 1, except that the same operation was performed as in Example 1 to obtain Example 4 Anti-static surface protective film.

(Example 5)

Weight average by copolymerizing 2-ethylhexyl acrylate, methoxypolyethylene glycol (400) methacrylate and 2-hydroxyethyl acrylate at a weight ratio of 90: 10: 4 30 parts by weight of a (meth) acrylate copolymer having a molecular weight of 380,000, dissolved in 70 parts by weight of ethyl acetate to form an adhesive (solid acetate content of 30% ethyl acetate solution), relative to 100 parts by weight This adhesive was added with 1.2 parts by weight of a HDI-based hardener (product name: Coronate HX, manufactured by Japan Polyurethane Industry Co., Ltd.) to obtain an application liquid, and the application liquid was used instead of the application liquid of Example 1. Other than that, it carried out similarly to Example 1, and obtained the antistatic surface protection film of Example 5.

(Example 6)

30 parts by weight of an acrylate copolymer having a weight average molecular weight of 520,000, which was obtained by copolymerizing 2-ethylhexyl acrylate and acrylic acid at a weight ratio of 100: 4, was dissolved in 70 parts by weight of ethyl acetate to form adhesion. Agent (solid content 30% ethyl acetate solution), and 1.0 part by weight of epoxy-based hardener (product name is TETRAD-C, Mitsubishi Gas Chemical Co., Ltd. is added to 100 parts by weight of the adhesive). ) (Manufactured by Mitsubishi Gas Chemical Company Inc.) to obtain an application liquid, and using this application liquid instead of the application liquid of Example 1, the same operation as in Example 1 was performed to obtain the antistatic of Example 6. Surface protective film.

The methods and results of the evaluation tests are shown below.

<Method for measuring peeling force of release film>

A sample of the antistatic surface protective film was cut with a width of 50 mm and a length of 150 mm. In a test environment of 23 ° C. × 50% RH, the peeling film was peeled in a 180 ° direction at a peeling speed of 300 mm / min using a tensile tester, and the strength at this time was measured, and this was used as the peeling force of the peeling film (N / 50mm).

<Method for measuring adhesive force of antistatic surface protective film>

An antiglare and low-reflection polarizer is laminated on the surface of the glass plate using a laminator (AG-LR polarizer). Then, an antistatic surface protective film cut into a width of 25 mm was bonded to the surface of the polarizing plate, and then stored in a test environment at 23 ° C. × 50% RH for one day. Then, the antistatic surface protective film was peeled off in a 180 ° direction at a peeling speed of 300 mm / min using a tensile tester, and the strength at this time was measured as the adhesive force (N / 25 mm).

<Method for measuring peeling static voltage of antistatic surface protective film>

An anti-glare low-reflection polarizer (AG-LR polarizer) was bonded to the surface of the glass plate using a laminator. Then, an antistatic surface protective film cut into a width of 25 mm was bonded to the surface of the polarizing plate, and then stored in a test environment at 23 ° C. × 50% RH for one day. Then, while using a high-speed peel tester (manufactured by TESTER Sangyo Co., Ltd.) to peel off the antistatic surface protective film at a peel rate of 40 m per minute, a surface potentiometer (Keyence The surface potential of the surface of the polarizing plate was measured every 10 ms, and the maximum value of the absolute value of the surface potential at this time was taken as the peeling static voltage (kV).

<Confirmation method of surface contamination property of antistatic surface protection film>

An anti-glare low-reflection polarizer (AG-LR polarizer) was bonded to the surface of the glass plate using a laminator. Then, an antistatic surface protective film cut into a width of 25 mm was bonded to the surface of the polarizing plate, and then stored in a test environment at 23 ° C. × 50% RH for 3 days and 30 days. Then, the antistatic surface protective film was peeled off, and the contamination of the surface of the polarizing plate was visually observed. As a criterion for determining the surface contamination, it was judged (○) when there was no pollution transfer on the polarizing plate, and (，) when it was confirmed that there was pollution transfer on the polarizing plate.

The obtained antistatic surface protective films of Examples 1 to 6 and Comparative Examples 1 to 2 were measured, and the measurement results are shown in Tables 1 to 2. Among them, "2EHA" refers to 2-ethylhexyl acrylate, "HEA" refers to 2-hydroxyethyl acrylate, "BA" refers to butyl acrylate, and "# 400G" refers to nailoxy polyethylene glycol (400 ) Methacrylate, "AA" means acrylic acid, "LiClO ₄ " means lithium perchlorate, and "Li (CF ₃ SO ₂ ) ₂ N" means lithium bis (trifluoromethanesulfonium) imide. The composition of the adhesive layer and the release agent layer is expressed in parts by weight such that the total amount of the adhesive agent or the total amount of the coating material forming the release agent layer is approximately 100 parts by weight.

From the measurement results shown in Tables 1 and 2, the following cases are known.

The anti-static surface protection films of Examples 1 to 6 of the present invention have proper adhesion, have no pollution to the surface of the adherend, and have a low peeling static voltage when the anti-static surface protection film is peeled from the adherend.

On the other hand, the antistatic surface protective film of Comparative Example 1 in which a polysiloxane compound and an antistatic agent were added to the adhesive layer was obtained from the adherend. When the antistatic surface protective film is peeled off, the peeling static voltage is low and good, but there is much contamination of the adherend after peeling. In Comparative Example 2 in which the amounts of the antistatic agent and the polysiloxane compound were reduced, although the contamination of the adherend was improved, the peeling static voltage when the antistatic surface protective film was peeled from the adherend high.

That is, in Comparative Examples 1 and 2 in which a polysiloxane compound and an antistatic agent were mixed in an adhesive, it was difficult to satisfy both the reduction of the peeling static voltage and the improvement of the contamination of the adherend. On the other hand, after adding a polysiloxane compound and an antistatic agent to the release agent layer, Examples 1 to 6 in which the polysiloxane compound and the antistatic agent were transferred to the surface of the adhesive layer have the following properties: A small amount of addition reduces the effect of peeling static voltage, so there is no pollution to the adherend, and a good antistatic surface protective film is obtained.

[Industrial availability]

The antistatic surface protective film of the present invention can be applied to, for example, optical films such as polarizing plates, retardation plates, and lens films for displays. In addition, in the production steps of various optical members and the like, the optical films can be protected. Members and other surfaces. In particular, when used as an antistatic surface protective film for an optical film such as an LR polarizing plate or an AG-LR polarizing plate whose surface has been subjected to antifouling treatment with a polysiloxane compound, a fluorine compound, or the like, it can be reduced. The amount of static electricity generated when peeling from the adherend.

The antistatic surface protection film of the invention has less pollution to the adherend and does not deteriorate with time (does not deteriorate over time), and has excellent anti-peeling static performance, so it can improve the yield of the production step. High utilization value.

1‧‧‧ substrate film

2‧‧‧adhesive layer

3‧‧‧ resin film

4‧‧‧ peeling agent layer

5‧‧‧ peeling film

Polysiloxanes and antistatic agents that are liquid at 7‧‧‧20 ° C

10‧‧‧Anti-static surface protective film

Claims (5)

A release film for an antistatic surface protection film, characterized in that the antistatic agent can be transferred only to the surface of the adhesive layer of the antistatic surface protection film that forms an adhesive layer on one side of the base film. In the above, the release film for an antistatic surface protection film is a laminate of a release agent layer containing an antistatic agent directly on one side of a resin film. The release agent layer contains dimethylpolysiloxane as a main component. A component release agent, a polyether-modified polysiloxane containing a polysiloxane compound that is liquid at 20 ° C., and a resin composition of an antistatic agent are formed, and the adhesive layer contains (meth) An acrylic adhesive layer obtained by cross-linking an acrylate copolymer and an adhesive composition of a cross-linking agent. The anti-static surface protective film is adhered to the adhesive layer with the release film interposed therebetween. In the case of a surface, the antistatic agent of the release agent layer can be transferred only to the surface of the adhesive layer. For example, the release film for an antistatic surface protection film according to item 1 of the application, wherein the release agent layer contains 100 parts by weight of the solid content of the release agent containing the dimethylpolysiloxane as a main component. The polyether-modified polysiloxane and the antistatic agent have a ratio of 5 to 100 parts by weight based on the solid content. For example, the release film for an antistatic surface protection film according to item 1 or 2 of the patent application scope, characterized in that the release film for the antistatic surface protection film is bonded to the surface of the adhesive layer with the release agent layer interposed In a test environment of 23 ° C. × 50% RH, the peeling force when peeling the release film for an antistatic surface protection film from the adhesive layer at a peeling speed of 300 mm / min in a direction of 180 ° using a tensile tester It is 0.2N / 50mm or less. For example, the release film for an antistatic surface protection film according to item 1 or 2 of the patent application scope, wherein the antistatic agent is an alkali metal salt. An antistatic surface protection film for an optical film, which is bonded with a release film for an antistatic surface protection film according to any one of claims 1 to 4 of the scope of patent application.