TWI641485B - Surface protection film and optical component attached with the same - Google Patents

Abstract

The present invention provides a surface protection film that can also be used for an optical film having unevenness on the surface, has little pollution to the adherend, has low pollution to the adherend, and does not deteriorate with time, and has excellent anti-peel electrostatic properties. , And optical parts using this surface protection film. An adhesive layer (2) is formed on one side of a base film (1) made of a transparent resin, and a release film (4) having a release layer (4) is bonded to the adhesive layer (2) ( In the surface protection film (10) of 5), the release film (5) is formed by laminating a release agent layer (4) on one side of the resin film (3), and the release agent layer (4) contains dimethyl polysilicon Oxyalkane as a main component of a release agent and an antistatic agent that does not react with the release agent. By transferring the antistatic component from the release film (5) to the surface of the adhesive layer (2), it can reduce the amount of The peeling static voltage when the adhesive layer (2) is peeled off from the body.

Description

Surface protection film and optical parts bonded with the surface protection film

The present invention relates to a surface protection film bonded to the surface of an optical component (hereinafter, sometimes referred to as an "optical film") such as a polarizing plate, a retardation plate, and a lens film for a display. In more detail, the present invention provides a surface protection film with less contamination to an adherend, a surface protection film having excellent anti-peel electrostatic properties without deterioration over time, and an optical component to which the surface protection film is bonded. .

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.

Conventionally, in the manufacturing steps of optical products, in order to prevent the adhesion of scratches and dirt, a surface protective film having an adhesive layer provided on one side of a base film has been generally used. The surface protective film is adhered to the optical film with an adhesive layer having a slight adhesive force. The reason why the adhesive layer is set to micro-adhesion is that in order to The used surface protection film can be easily peeled off when it is peeled off from the surface of the optical film, and in order to prevent the adhesive from adhering and remaining on the optical film of the product as an adherend (so-called anti-adhesive agent) Residues occur).

In recent years, in the production process of liquid crystal display panels, the peeling static voltage generated when the surface protective film attached to the optical film is peeled off and removed, the circuits such as a driver IC for controlling the display screen of the liquid crystal display are destroyed. The parts and the orientation of the 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.

In recent years, with the spread of 3D displays (stereoscopic displays), FPR (Film Patterned Retarder) films are sometimes bonded to the surface of optical films such as polarizing plates. The surface protective film bonded to the surface of an optical film such as a polarizing plate is peeled off, and then 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 in 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 of the adherend by the surface protective film, the following method is adopted: first, the surface protective film attached to the optical film such as a polarizing plate is peeled off 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 by the adherend is trace, However, if there is a difference in contamination with 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, based on the results of determination by such a strict evaluation method, there is also a need for a surface protective film that has no problem with the surface contamination of the adherend.

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

For example, Patent Document 1 discloses a surface protective 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 adhesive composition composed of an acrylic polymer, a polyether polyol compound, and an alkali metal salt treated with an anion-adsorbing compound, and a surface protection using the same. membrane.

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.

[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

In the aforementioned Patent Documents 1 to 4, an antistatic agent is added inside the adhesive layer. However, the thicker the adhesive layer is, the more the antistatic agent moves from the adhesive layer to the adherend to which the surface protective film is attached as time passes after the adherence to the adherend. When the amount of the antistatic agent moved to the adherend increases, the appearance quality of the optical film as the adherend decreases; or when the FPR film is bonded, there is a possibility that the adhesiveness of the FPR film decreases.

In order to reduce the change with time of the antistatic agent moving from the adhesive layer to the adherend at this time, if the thickness of the adhesive layer is reduced, other problems will occur. For example, when used for an optical film with unevenness on the surface, such as a polarizing plate after anti-glare treatment is applied to prevent glare, the adhesive layer cannot meet the unevenness on the surface of the optical film and mix bubbles, or because the optical film and the The adhesion area of the adhesive is reduced to reduce the adhesive force, and there is a problem that the protective film is separated or peeled during use.

Therefore, there is a need for a surface protection film for use in an optical film, which can also be used for an optical film having unevenness on the surface, which has very little pollution to the adherend and does not change the contamination property to the adherend over time. In addition, it is also possible to reduce the surface protection film when peeling off the static voltage when the surface protection film is peeled.

The inventors have carefully studied this subject.

To reduce contamination of adherends and also reduce contamination over time It is necessary to reduce the amount of antistatic components that are supposed to contaminate the adherend. However, when the amount of the antistatic component 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 component.

As a result, it was found that instead of adding an antistatic agent to the adhesive and mixing to form an adhesive layer, the adhesive composition was coated and dried to laminate the adhesive layer, and then an appropriate amount of antistatic was applied to the surface of the adhesive layer. The component 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 circumstances, and an object thereof is to provide an optical film having unevenness on the surface, which can be used and has less pollution to an adherend, and that the low pollution to the adherend does not change with time. A surface protection film that changes over time, and further has a surface protection film with excellent anti-peel electrostatic properties without deterioration over time, and an optical component using the surface protection film.

In order to solve the above-mentioned problems, the technical idea of the surface protective film of the present invention is to apply an appropriate amount of an antistatic agent to the surface of the adhesive layer after the adhesive composition is applied and dried to laminate the adhesive layer. The contamination property to the adherend is suppressed, and the peeling static voltage when peeled from the optical film as an adherend can be suppressed.

In order to solve the above-mentioned problems, the present invention provides a surface protective film having an adhesive layer formed on one surface of a base film made of a resin having transparency, and a release agent is bonded to the adhesive layer. Layer of release film A surface protection film, wherein the release film is formed by laminating a release agent layer on one side of a resin film, and the release agent layer contains a release agent containing dimethylpolysiloxane as a main component and does not occur with the release agent. In the reacted antistatic agent, the antistatic agent component is transferred from the release film to the surface of the adhesive layer, thereby reducing the peeling static voltage when the adhesive layer is peeled from the adherend.

The antistatic agent is preferably an alkali metal salt.

In addition, it is preferable that the adhesive layer is obtained by crosslinking a (meth) acrylate copolymer.

The peeling force when peeling the peeling film from the adhesive layer is preferably 0.2 N / 50 mm or less.

In addition, the present invention provides an optical component to which the above-mentioned surface protection film is bonded.

The surface protection film of the present invention has less pollution to the adherend, and the low pollution property to the adherend does not change with time. In addition, according to the present invention, an optical film having unevenness on the surface, such as an AG polarizing plate, can be used. In addition, the surface protection film according to the present invention can provide a surface protection capable of suppressing the peeling static voltage that occurs when peeling from an optical film as an adherend, and having excellent anti-peeling electrostatic properties without deterioration over time. Film, and optical parts using the surface protection film.

According to the surface protective film of the present invention, the surface of the optical film can be reliably protected, and therefore, productivity can be improved and yield can be improved.

1‧‧‧ substrate film

2‧‧‧ Adhesive layer

3‧‧‧ resin film

4‧‧‧ peeling agent layer

5‧‧‧ peeling film

7‧‧‧Antistatic agent

8‧‧‧ Adhered body (optical parts)

10‧‧‧ surface protective film

11‧‧‧Surface protective film after peeling off the peeling film

20‧‧‧ Optical parts with surface protective film

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

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

Fig. 3 is a sectional view showing an embodiment of an optical component according to 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 a surface protective film of the present invention. In this surface protection film 10, an adhesive layer 2 is formed on one surface 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 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 component can be performed in the state which bonded the surface protection film to the optical component 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 subjected to uniaxial stretching or biaxial stretching. The stretching ratio of the stretched film and the orientation angle in the axial direction formed by the crystallization of the stretched film may be controlled to specific values.

The thickness of the base film 1 used in the surface protection film 10 of the present invention is not particularly limited. For example, a thickness of about 12 to 100 μm is preferred; a thickness of about 20 to 50 μm is easy to handle, so More ideal.

In addition, if necessary, an antifouling layer, an antistatic layer, and a hard coat 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. . 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 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 adherent layer of the adherend. However, it is not particularly limited, but in view of durability and the like after bonding to an optical film, an 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 other monomers may be (meth) acrylic acid esters; as a monomer other than the main monomer, one or two or more kinds of (meth) acrylic acid may be contained. Monomers other than acrylate.

In addition, a polyoxyalkylene-containing compound may be copolymerized or mixed with a (meth) acrylate copolymer. Examples of the compound containing a copolymerizable polyoxyalkylene include polyethylene glycol (400) monoacrylate, polyethylene glycol (400) monomethacrylate, and methoxypolyethylene glycol (400 ) Acrylate, methoxy polyethylene glycol (400) methacrylate, polypropylene glycol (400) monoacrylic acid Esters, 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 monomers and functional monomers of the (meth) acrylate copolymer, it is possible to obtain a polyoxyalkylene-containing copolymer. Adhesive.

The polyoxyalkylene group-containing compound that can be mixed with the (meth) acrylate copolymer is preferably a (meth) acrylate copolymer containing a polyoxyalkylene group, and more preferably a polyoxyalkylene group-containing compound. Examples of polymers of (meth) acrylic monomers 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 Polymers such as methoxy polypropylene glycol (400) methacrylate. By mixing these polyoxyalkylene-containing compounds with the (meth) acrylate copolymer, a binder obtained by adding a polyoxyalkylene-containing compound can be obtained.

As a hardening | curing agent added to the adhesive agent layer 2, as a crosslinking agent which bridge | crosslinks a (meth) acrylate copolymer, an isocyanate compound, an epoxy compound, a melamine compound, a metal chelate, etc. are mentioned. Examples of the thickener include rosin, coumarone-indene, terpene, petroleum, and phenol.

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

The release film 5 used in the surface protection film 10 of the present invention is formed by laminating a release agent layer 4 on one side of the resin film 3, and the release agent layer 4 contains dimethylpolysiloxane as A main component release agent and an antistatic agent which does not react with the release agent.

Examples of the resin film 3 include a polyester film, a polyamide film, a polyethylene film, a polypropylene film, and a polyimide film. From the viewpoint of excellent transparency and 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 formed by the crystallization of the stretched film 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 an easy-adhesion treatment such as surface modification by corona discharge, application of a primer, and the like, as necessary.

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 (Tao Corning Toray Co., Ltd. (manufactured by Dow Corning Toray Co., Ltd.) and the like. 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.

As the antistatic agent constituting the release agent layer 4, it is preferred that the release agent solution containing dimethylpolysiloxane as a main component has good dispersibility and does not hinder the use of dimethylpolysiloxane as a main component. Cured antistatic agent for release agents. In addition, for the antistatic agent, in order to impart antistatic effect to the adhesive layer from the release agent layer 4 to the surface of the adhesive layer 2, it is preferable not to peel off with dimethylpolysiloxane as a main component. Antistatic agents that react. As such an antistatic agent, an alkali metal salt is preferred.

Examples of the alkali metal salt include lithium, sodium, and potassium metal salts. Specifically, for example, is preferably used by Li ^+, Na ^+, K ⁺ cations and ^{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 and the like 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 singly or in combination of two or more kinds. In order to stabilize the ionic substance, a compound containing a polyoxyalkylene structure may be added.

Antistatic agent compared to the release agent containing dimethyl polysiloxane as the main component The amount added depends on the type of antistatic agent and the degree of affinity with the release agent, as long as the static voltage required for peeling the surface protection film from the adherend and the contamination of the adherend are considered. It is only necessary to set properties such as adhesiveness and adhesion characteristics.

The release agent layer 4 may be a release agent layer 4 formed by a mixture of a release agent containing dimethylpolysiloxane as a main component and an antistatic agent that does not react with the release agent. There is no particular limitation on the method of mixing the release agent containing dimethylpolysiloxane as the main component and the antistatic agent. Any of the following mixing methods may be adopted: a method in which an antistatic agent is added to a release agent containing dimethylpolysiloxane as a main component and mixed, and then a catalyst for curing the release agent is added and mixed; an organic method is used in advance A method of diluting a release agent containing dimethyl polysiloxane as a main component, adding an antistatic agent and a curing agent for curing the release agent, and mixing them; a method of removing a poly dimethyl polysiloxane as a main component in advance A method in which an agent is diluted in an organic solvent, a catalyst is added and mixed, and then an antistatic agent is added and mixed. 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.

The mixing ratio of the release agent containing dimethyl polysiloxane as the main component and the antistatic agent is not particularly limited, but it is relative to the solid content of the release agent containing dimethyl polysiloxane as the main component. The component 100 is preferably an antistatic agent having a ratio of about 5 to 100 in terms of solid content. Relative to the solid content 100 of the release agent containing dimethyl polysiloxane as the main component, if the addition amount of the antistatic agent in terms of solid content is less than 5, the transfer amount of the antistatic agent to the surface of the adhesive layer It also becomes smaller, making it difficult for the adhesive layer to exert an antistatic function. In addition, with respect to the solid content 100 of a release agent containing dimethylpolysiloxane as a main component, if If the antistatic agent is added in an amount of more than 100 in terms of solid content, the peeling agent containing dimethyl polysiloxane as the main component together with the antistatic agent will also be transferred to the surface of the adhesive layer. Reduce the adhesive properties of the adhesive layer.

In the present invention, both the method of forming the adhesive layer 2 on the base film 1 of the surface protection film 10 and the method of bonding the release film 5 can be performed by a known method and are not particularly limited. Specifically, (1) a method of applying the resin composition for forming the adhesive layer 2 on one surface of the base film 1 and drying the adhesive composition to form the adhesive layer and bonding the release film 5; (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, known coating methods such as reverse coating, comma 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 surface protection 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, addition amount, and the like of the 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 surface protection film of the present invention.

By peeling the release film 5 from the surface protection film 10 shown in FIG. 1, a part of the antistatic agent (reference numeral 7) contained in the release agent layer 4 of the release film 5 is transferred (adhered) to the surface The surface of the adhesive layer 2 of the protective film 10. Therefore, in FIG. 2, the antistatic agent transferred to the surface of the adhesive layer 2 of the surface protective film is schematically shown by the spots of reference numeral 7. By transferring the components of the antistatic agent 7 from the release film 5 to the surface of the adhesive layer 2, compared with the adhesive layer 2 before the transfer, the peeling static voltage when the adhesive layer 2 is peeled off from the adherend can be reduced. . The peeling static voltage when the adhesive layer is peeled from the adherend can be measured by a known method. For example, after a surface protective film is bonded to an adherend such as a polarizing plate, a high-speed peel tester (manufactured by TESTER Sangyo Co., Ltd.) is used at a peeling speed of 40 m per minute. While peeling the surface protective film, the surface potential of the surface of the adherend was measured using a surface potentiometer (manufactured by Keyence Corporation) every 10 ms, and the maximum value of the absolute value of the surface potential at this time was taken as the peel Static voltage (kV).

In the surface protection film of the present invention, when the surface protection film 11 in a state where the release film is peeled off as shown in FIG. 2 is attached to the adherend, the antistatic agent transferred to the surface of the adhesive layer 2 Make contact with the surface of the adherend. With this operation, it is possible to suppress the peeling static voltage when the surface protective film is peeled from the adherend again.

3 is a cross-sectional view showing an embodiment of an optical component according to the present invention.

In a state where the release film 5 is peeled from the surface protective film 10 of the present invention and the adhesive layer 2 is exposed, the adhesive layer 2 is bonded to the optical component 8 as an adherend.

That is, FIG. 3 shows the optical component 20 to which the surface protection film 10 of the present invention is bonded. Examples of the optical component include a polarizing plate, a retardation plate, and a lens. Optical films such as a film, a polarizing plate also serving as a retardation plate, and a polarizing plate also serving as a lens film. Such an optical component is used as a component of a liquid crystal display device such as a liquid crystal display panel, an optical system device of various measuring instruments and the like. Examples of the optical component include optical films such as antireflection films, hard coat films, and transparent conductive films for touch panels.

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

[Example]

Hereinafter, the present invention will be further explained by examples.

(Example 1)

(Manufacture of surface protection film)

5 parts by weight of an addition reaction type polysiloxane (product name is SRX-345, manufactured by Dow Corning Toray Co., Ltd.), 7.5 parts by weight of a 10% ethyl acetate solution of lithium perchlorate, and 95 Part by weight of toluene and a mixed solvent of 1: 1 ethyl acetate and 0.05 parts by weight of a platinum catalyst (product name: SRX-212, manufactured by Dow Corning Toray Co., Ltd.) are mixed together and stirred to prepare A coating material for forming the release agent layer of Example 1 was described. Using a Müller rod, the coating for 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. Then, it was dried in a hot-air loop-type oven at 120 ° C. for 1 minute to obtain the release film of Example 1. On the other hand, 2-ethylhexyl acrylate and propylene will be used in a weight ratio of 100: 4. 30 parts by weight of an acrylate copolymer having a weight average molecular weight of 470,000, which was copolymerized with 2-hydroxyethyl enoate, was dissolved in 70 parts by weight of ethyl acetate to obtain a binder (a solid content of 30% Ethyl acetate solution), and 1.2 parts by weight of HD1 type curing agent (product name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) is added to 100 parts by weight of the adhesive. ) And mixed to form an application liquid, and the application liquid was applied to the surface of a polyethylene terephthalate film having a thickness of 38 μm so as to have a thickness of 20 μm after drying, and then heated by hot air at 100 ° C. The loop oven 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 Example 1 produced as described above was bonded. The obtained adhesive film was held in an environment at 40 ° C. for 5 days to cure the adhesive, and the surface protective film of Example 1 was obtained.

(Example 2)

A surface protection film of Example 2 was obtained in the same manner as in Example 1 except that the coating material for forming the release agent layer of Example 1 was applied so that the thickness after drying became 0.1 μm.

(Example 3)

Except for the addition reaction type polysiloxane of Example 1, SRX-211 (product name) manufactured by Dow Corning Toray Co., Ltd. was used, and lithium bis (trifluoromethanesulfonium) imide 10% was used. A surface protection film of Example 3 was obtained in the same manner as in Example 1 except that 10 parts by weight of the ethyl acetate solution was used instead of 7.5 parts by weight of the 10% ethyl acetate solution of lithium perchlorate.

(Comparative example 1)

Add 5 parts by weight of addition reaction type polysiloxane (product name is SRX-345, manufactured by Dow Corning Toray Co., Ltd., 95 parts by weight of toluene and ethyl acetate mixed solvent of 1: 1, and 0.05 parts by weight of platinum catalyst (product name is SRX-212, Dow Corning Toray (manufactured by Toray Co., Ltd.) was mixed together and stirred to prepare a coating material for forming a release agent layer of Comparative Example 1. The coating material for forming the release agent layer of Comparative Example 1 was applied on a surface of a polyethylene terephthalate film having a thickness of 38 μm using a Meyer bar so that the thickness after drying was 0.2 μm. It dried in the hot-air loop-type oven at 120 degreeC for 1 minute, and the peeling film of the comparative example 1 was obtained. On the other hand, with respect to 100 parts by weight of the binder of Example 1 (ethyl acetate solution having a solid content of 30%), 5 parts by weight of a 10% ethyl acetate solution of lithium perchlorate and HDI were added and mixed. Type curing agent (product name: Coronate HX, manufactured by Japan Polyurethane Industry Co., Ltd.) 1.2 parts by weight to form an application liquid, and the application liquid is applied to a polymer pair having a thickness of 38 μm so that the thickness after drying becomes 20 μm. The surface of the ethylene phthalate film was then dried in a hot air loop 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 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 cure the adhesive, and a surface protective film of Comparative Example 1 was obtained.

(Comparative example 2)

A surface protection film of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that 0.2 parts by weight of a 10% ethyl acetate solution of lithium perchlorate was used.

(Example 4)

Acrylic acid 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 30 parts by weight of the ester copolymer was dissolved in 70 parts by weight of ethyl acetate to form a binder (30% ethyl acetate solution in solid content), and 1.2 parts by weight of the binder was added and mixed with 100 parts by weight of the binder. An HDI-based curing agent (product name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) was used to obtain an application liquid. The application liquid was used in place of the application liquid of Example 1 except that the same operation was performed as in Example 1. A surface protection film of Example 4 was obtained.

(Example 5)

The weight average molecular weight of 2-ethylhexyl acrylate, methoxypolyethylene glycol (400) methacrylate and 2-hydroxyethyl acrylate in a weight ratio of 90: 10: 4 was 380,000 30 parts by weight of acrylate copolymer was dissolved in 70 parts by weight of ethyl acetate to form a binder (30% ethyl acetate solution in solid content), and 1.2 parts by weight was added to and mixed with 100 parts by weight of the binder. HDI-based curing agent (product name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) to obtain an application liquid. The application liquid was used in place of the application liquid of Example 1 except that the application liquid was used in the same manner as in Example 1. By performing the operation, a surface protection film of Example 5 was obtained.

(Example 6)

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

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

<Method for measuring peeling force of release film>

A sample of the surface protection 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 surface protective film>

An anti-glare and low-reflection polarizer (AG-LR polarizer) was laminated on the surface of the glass plate using a laminator. Then, a surface protection 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 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, and this was taken as the adhesive force (N / 25 mm).

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

An anti-glare and low-reflection polarizer (AG-LR polarizer) was laminated on the surface of the glass plate using a laminator. Then, a surface protection 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 the surface protective film at a peeling speed of 40 m per minute, a surface potentiometer (Keyence (Stocks) (Manufactured by Keyence Corporation), 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).

<A method for confirming the surface contamination of a surface protective film>

An anti-glare and low-reflection polarizer (AG-LR polarizer) was laminated on the surface of the glass plate using a laminator. Then, a surface protection 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 surface protective film was peeled off, and the presence or absence of contamination on the surface of the polarizing plate was visually observed to confirm the surface contamination. As a criterion for determining the surface contamination, it was judged as (○) when there was no contamination transfer on the polarizing plate, and it was judged as (×) when contamination transfer was confirmed on the polarizing plate.

The obtained 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 (trifluoromethanesulfonyl) imide.

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

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

On the other hand, in the surface protection film of Comparative Example 1 in which an antistatic agent was added to the adhesive layer, although the peeling static voltage was low and good when the surface protection film was peeled from the adherend, the peeling was performed on the adherend after peeling. More pollution. In Comparative Example 2 in which the amount of the antistatic agent was reduced, although the contamination property to the adherend was improved, the peeling static voltage when the surface protective film was peeled from the adherend was high.

That is, according to Comparative Examples 1 and 2 in which an antistatic agent was mixed with an adhesive, it was difficult to achieve both a reduction in peeling static voltage and an improvement in contamination of an adherend. On the other hand, Examples 1 to 6 in which an antistatic agent was added to the release agent layer and transferred to the surface of the adhesive layer had the effect of reducing the peeling static voltage with a small amount of addition. Pollution, a good surface protective film was obtained.

(Industrial availability)

The surface protection film of the present invention can be applied to, for example, optical films such as polarizing plates, retardation plates, and lens films. In addition, in the production steps of various optical components and the like, the surface protective films are bonded to the optical components and the like. Used to protect its surface. In addition, the surface protection film of the present invention can reduce the amount of static electricity generated when peeling from the adherend, and it can reduce the degradation of the antistatic properties with time and less pollution to the adherend, and can improve the yield of the production step. The industrial use value is great.

Claims (5)

A release film for an antistatic surface protection film. An antistatic surface protection film with an adhesive layer formed on one side of a base film can transfer an antistatic agent to the surface of the aforementioned adhesive layer, and is characterized in that the aforementioned adhesive The layer is an acrylic adhesive layer cross-linked with an adhesive composition containing a (meth) acrylate copolymer and a cross-linking agent. The cross-linking agent is selected from the group consisting of an isocyanate compound, an epoxy compound, a melamine compound, and a metal chelate. One or more of the compound group consisting of a substance, the release film for an antistatic surface protection film is formed by laminating a release agent layer containing an antistatic agent on one side of a resin film, and the release agent layer is formed by A polysiloxane containing a release agent as a main component and a resin composition of an antistatic agent which does not react with the release agent, and the release film for the antistatic surface protection film is bonded to the adhesive through the release agent layer. In the case of the surface of the layer, the antistatic agent component of the release agent layer is changed from the release agent layer of the release film for the antistatic surface protection film to the surface of the adhesive layer. Transfer. For example, the release film for an antistatic surface protection film according to item 1 of the patent application, wherein the aforementioned release agent layer is 100 parts by weight of the solid content of the release agent containing the aforementioned dimethylpolysiloxane as a main component, and the aforementioned antistatic The agent contains 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 application, wherein the release film for an antistatic surface protection film is adhered to the surface of the adhesive layer through the release agent layer, and then the temperature is 23 ° C × In a 50% RH test environment, a tensile tester was used at a peeling speed of 300 mm / min in a direction of 180 °, and the peeling force when peeling from the adhesive layer was 0.2 N / 50 mm 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 aforementioned antistatic agent is an alkali metal salt. An antistatic surface protective film for an optical film, which is bonded with a release film for an antistatic surface protective film as described in any one of claims 1 to 4 of the scope of patent application.