TWI665086B - Surface-protective film and optical component attached with the same - Google Patents

Abstract

The present invention provides an optical film having unevenness on its surface. Surface protection film for use with less pollution to adherends and low pollution to adherends without change over time, and surface protection film with excellent anti-peel electrostatic properties without deterioration over time, and using the surface Protective film for optical components.

In 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 agent layer (4) is bonded to the adhesive layer (2). A release film (5), wherein the release film (5) is formed by laminating a release agent layer (4) on one side of a resin film (3), and the release agent layer (4) contains a resin containing a long-chain alkyl group as a main component A component release agent and an antistatic agent that does not react with the release agent. The antistatic component is transferred from the release film (5) to the surface of the adhesive layer (2), reducing the transfer of the adhesive layer (2) from the adherend. Peeling static voltage during peeling.

Description

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

The present invention relates to a surface protection film that is bonded to optical components (hereinafter, also referred to as "optical film") such as a polarizing plate, a retardation plate, and a lens film for a display. In more detail, a surface protection film with less contamination to an adherend is provided, and further, a surface protection film having excellent anti-peeling electrostatic properties without deterioration over time (without deterioration over time), and a sticker An optical component incorporating this surface protection film.

Currently, when manufacturing and transporting optical films such as polarizing plates, retardation plates, display lens films, anti-reflection films, hard coating films, transparent conductive films for touch panels, and optical products such as displays, A surface protective 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 injuries during the manufacturing process of optical products For the adhesion of marks and dirt, a surface protection film having an adhesive layer provided on one side of a base film is 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 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 adherend. Phenomenon on the optical film of the product (so-called preventing the occurrence of adhesive residue).

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 components 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. 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 of an adherend by a surface protective film, the following method is adopted: First, the surface protective film bonded on the optical film such as a polarizing plate is peeled off, and then re-bonded with air bubbles mixed, and the re-bonded article is heat-treated under predetermined conditions, and then the surface protective film is peeled off. And observe the surface of the adherend. In this evaluation method, even if the surface contamination of the adherend is slight, if there is a difference in the surface contamination of the adherend between the part where the air bubbles are mixed and the part in contact with the adhesive of the surface protective film, it will be regarded as air bubbles. Traces (sometimes called "bubble stains") remain. 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.

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 protective film using the composition. .

In addition, Patent Document 4 discloses a method comprising an ionic liquid and alkali gold. An adhesive composition comprising a metal salt, 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 Application Laid-Open No. 2005-131957

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

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

Patent Document 4: Japanese Patent Application 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 protection film is attached as time passes after the adherence to the adherend. When the amount of the antistatic agent moved to the adherend is larger, there is a possibility that the appearance quality of the optical film as the adherend is lowered, or the adhesiveness of the FPR film is lowered when the FPR film is bonded.

If the thickness of the adhesive is reduced in order to reduce such a time-varying change in the movement of the antistatic agent from the adhesive layer to the adherend, other problems arise. For example, when it is used for an optical film having unevenness on the surface such as a polarizing plate to which anti-glare treatment is applied for anti-glare, there is a problem that the adhesive cannot follow the unevenness on the surface of the optical film and mix bubbles, or Because the adhesion area between the optical film and the adhesive is reduced, the adhesive force is reduced, and the surface protective film floats or peels during use.

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 adherends, and low pollution to adherends does not occur over time. A surface protection film having a changed surface protection film and excellent anti-peeling electrostatic properties without deterioration over time (without degradation over time), and an optical component using the surface protection film.

The present inventors have conducted intensive studies on this subject.

In order to reduce the contamination of the adherend and also to reduce the chronological change in contamination, it is necessary to reduce the amount of the antistatic agent that is supposed to contaminate 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 for suppressing the peeling static voltage when peeling a surface protective film from an adherend to a relatively low level 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 and mixing to form an adhesive layer, the adhesive composition containing no antistatic agent was applied and dried to laminate the adhesive layer, and then the adhesive layer and the A release film having an antistatic agent-containing release agent layer was bonded to the release agent layer in a contact manner, and an appropriate amount of an antistatic component was transferred from the release film side to give the surface of the adhesive layer, thereby obtaining a charge amount capable of suppressing peeling. Based on the above findings, the present invention has been completed.

That is, this invention provides the surface protection film which formed the adhesive layer on the single side | surface of the base material film which consists of a transparent resin, and peeled the release agent layer on this adhesive layer, The surface protection film of a film, wherein the release film is formed by laminating a release agent layer on one side of a resin film, The release agent layer contains a release agent containing a long-chain alkyl group-containing resin as a main component and an antistatic agent that does not react with the release agent. The antistatic agent component is transferred from the release film to the surface of the adhesive layer. This reduces the peeling static voltage when the adhesive layer is peeled from the adherend.

The antistatic agent is preferably an alkali metal salt.

The adhesive layer is preferably formed by crosslinking a (meth) acrylate copolymer.

The surface potential when the surface protective film is peeled from the optical film as an adherend is preferably +0.7 kV to -0.7 kV.

The peeling force when the peeling film is peeled from the adhesive layer is preferably 0.005 to 0.3 N / 50 mm.

The present invention also provides an optical component having the above-mentioned surface protective film bonded thereto.

The 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). Moreover, according to this invention, even if the to-be-adhered body is an optical film which has unevenness on the surface, such as an AG polarizing plate, it can be used. In addition, the surface protection film according to the present invention can provide a peeling static voltage which can suppress the peeling of the surface protection film from being peeled off from the optical film as an adherend, and has excellent degradation resistance without degradation over time. Surface protective film with electrostatic properties, and optical component using the surface protective film.

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

1‧‧‧ substrate film

2‧‧‧ Adhesive layer

3‧‧‧ resin film

4‧‧‧ peeling agent layer

5‧‧‧ peeling film

7‧‧‧Antistatic agent

8‧‧‧ Adhered body (optical component)

10‧‧‧ surface protective film

11‧‧‧ Surface protection film with peeling film peeled off

20‧‧‧ Optical component 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 cross-sectional view showing an embodiment of an optical component of the present invention.

[Form of Implementing Invention]

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

FIG. 1 is a cross-sectional view showing the concept of a surface protective film of the present invention. This surface protective film 10 is formed with an adhesive layer 2 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 are preferably used. ), Polyester films such as polybutylene terephthalate. The substrate 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. In addition, 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 value.

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 it is more convenient Preferred.

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 adherend layer of the adherend. That is, there is no particular limitation, but in view of durability and the like after bonding to an optical film, a binder 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, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, etc .; the comonomers include acrylonitrile, vinyl acetate, methyl methacrylate, ethyl acrylate, etc .; the functionality Examples of the monomer 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, and may contain one or two or more kinds of (meth) acrylic acid as monomers other than the main monomer. Monomers other than esters.

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, a bond composed of the polyoxyalkylene-containing copolymer can be obtained. Agent.

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 and the (meth) acrylate copolymer, a binder to which a polyoxyalkylene-containing compound is added can be obtained.

As the curing agent added to the adhesive layer 2, as the crosslinking agent for crosslinking the (meth) acrylate copolymer, an isocyanate compound may be mentioned. Compounds, epoxy compounds, melamine compounds, metal chelates, etc. 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 It is preferable because it has excellent properties. In addition, from the viewpoint of excellent operability when peeling the peeling film 5 from the surface protective film 10, the conditions for peeling force of the peeling film 5 from the adhesive layer 2 at a peeling speed of 0.3 m / min and a peeling angle of 180 ° are preferred. The measurement is 0.005 to 0.3N / 50mm.

In addition, the release film 5 used in the surface protective 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 a resin containing a long-chain alkyl group as The main component is a 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, a polyester film is particularly preferred. . 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, for example, a thickness of about 12 to 100 μm is preferred; a thickness of about 20 to 50 μm is easy to handle because This is more preferred.

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 which comprises a resin containing a long-chain alkyl group as a main component constituting the release agent layer 4 include an amino alkyd resin containing a long-chain alkyl group, an acrylic resin containing a long-chain alkyl group, and a long-chain fat. Group pendant resin (at least one polymer selected from the group consisting of polyvinyl alcohol, ethylene / vinyl alcohol copolymer, polyethyleneimine, and hydroxyl-containing cellulose derivatives, and isocyanates containing long-chain alkyl groups Known reaction products such as long-chain alkyl-containing strippers. It may be a release agent that adds a curing agent and an ultraviolet initiator to perform a curing reaction, or a release agent that volatilizes a solvent and cures.

The "long-chain alkyl group" is preferably an alkyl group having 8 to 30 carbon atoms. The number of carbon atoms may be 10 or more, 12 or more, 18 or less, 24 or less, and among them, a linear alkyl group is preferred. Specific examples include those selected from the group consisting of decyl, undecyl, lauryl, dodecyl, tridecyl, myristyl, tetradecyl, pentadecyl, cetyl, palm One or two or more of alkyl, hexadecyl, heptyl, stearyl, stearyl, nonadecyl, eicosyl, behenyl, and the like.

As a commercially available product of a long-chain alkyl group-containing resin-based release agent, for example, ASHIO RESIN (manufactured by ASHIO CO., LTD. , Registered trademark) RA-30; Piroiru ( , Registered trademark) 1010, Piroiru 1010S, Piroiru 1050, Piroiru HT; Resem N-137 of Zhongjing Oil Co., Ltd .; Exceparl ( , Registered trademark) PS-MA; Tess Fine (made by Hitachi Chemical Co., Ltd. , Registered trademark) 303, etc.

As the antistatic agent constituting the release agent layer 4, it is preferable that the dispersant has a long-chain alkyl group-containing resin as a main component, and has good dispersibility, and does not hinder a release agent containing a long-chain alkyl group-containing resin as a main component. Cured antistatic agent. In addition, in order to impart an antistatic effect to the adhesive layer from the release agent layer 4 to the surface of the adhesive layer 2, an antistatic agent that does not react with a release agent containing a long-chain alkyl group-containing resin as a main component may be used. . As such an antistatic agent, an alkali metal salt is preferable.

Examples of the alkali metal salt include metal salts of lithium, sodium, and potassium. Specifically, for example, preferably a metal salt consisting of an anion and a cation, wherein the cation is selected from Li ^+, Na ^+, K ^+, the anion is selected from ^{Cl -, Br -, I -} , BF 4 -, PF _{^{6 -, SCN -, ClO 4}} -, CF 3 SO 3 -, (FSO 2) 2 N -, (CF 3 SO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, (CF 3 SO ₂ ) ₃ C ^-Medium . Among them, LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li (FSO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₂ N, and Li (C ₂ F ₅ SO) are particularly preferably used. ₂ ) Lithium salts such as ₂ N and Li (CF ₃ SO ₂ ) ₃ C. 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 structure may be added.

The amount of the antistatic agent added to the stripping agent containing a resin containing a long-chain alkyl group as a main component varies depending on the type of the antistatic agent and the degree of affinity with the stripping agent, as long as it takes into account The peeling static voltage required when the surface protective film is peeled off, the contamination property to the adherend, the adhesion characteristics, and the like may be set.

There is no particular limitation on the method of mixing the release agent and the antistatic agent containing the long-chain alkyl group-containing resin as a main component constituting the release agent layer 4. Any one of the following mixing methods may be adopted: a method in which an antistatic agent is added to a stripper containing a long-chain alkyl group-containing resin as a main component, and then a catalyst for curing the stripper is added and mixed; a method in advance is used; An organic solvent is used to dilute a long-chain alkyl group-containing resin as a main component, and an antistatic agent and a curing agent for a curing agent are added and mixed. The organic solvent is used to dilute the long-chain alkyl group-containing resin as a main component. A method of adding a catalyst to the component release agent and mixing the components, and then adding an antistatic agent and mixing the components. 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 the long-chain alkyl group-containing resin as the main component, but the solid ratio of the release agent containing the long-chain alkyl-group-containing resin as the main component The component 100 is preferably an antistatic agent in a ratio of about 5 to 100 in terms of solid content. Relative to the solid content 100 of the release agent containing a resin containing a long-chain alkyl group as a main component, if the amount of the antistatic agent added 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 the release agent containing a resin containing a long-chain alkyl group as a main component, if the amount of the antistatic agent added in terms of solid content exceeds 100, the antistatic agent is used together with the antistatic agent to contain a long chain. The peeling agent whose main component is an alkyl resin is also transferred to the surface of the adhesive layer, and therefore, the adhesive properties of the adhesive layer are reduced.

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 then bonding the release film 5 to the 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 it 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 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 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. Further, the surface potential is more preferably +0.5 kV to -0.5 kV, and the surface potential is particularly preferably +0.3 kV to -0.3 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 as shown in FIG. A part of the antistatic agent (reference numeral 7) contained in the release agent layer 4 of the film 5 is transferred (adhered) to the surface of the adhesive layer 2 of the surface protective film 10. Therefore, in FIG. 2, the antistatic agent attached to the surface of the adhesive layer 2 of the surface protective film is schematically shown by the spots of reference numeral 7. The components of the antistatic agent 7 are transferred from the release film 5 to the surface of the adhesive layer 2, and the peeling static voltage when the adhesive layer 2 is peeled from the adherend is reduced compared with the adhesive layer 2 before the transfer. The peeling static voltage when the adhesive layer is peeled from the adherend can be measured by a known method. For example, after the surface protective film is bonded to an adherend such as a polarizing plate, the surface is peeled off at a peeling speed of 40 m per minute using a high-speed peel tester (manufactured by TESTER Sangyo Co., Ltd.). While protecting the 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 used as the peeling 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. By this operation, the peeling static voltage when the surface protective film is peeled from the adherend again can be suppressed to a low level.

FIG. 3 is a cross-sectional view showing an embodiment of an optical component of 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 member 8 as an adherend.

That is, FIG. 3 shows the optical properties of the surface protective film 10 bonded to the present invention. Part 20. Examples of the optical component 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 component is used as a component 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 component include optical films such as antireflection films, hard coat films, and transparent conductive films for touch panels.

According to the optical member of the present invention, when the 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. Therefore, there is no need to worry about destroying circuit components such as a driving IC, a TFT element, a gate line driving circuit, etc., and it is possible to 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]

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

(Manufacture of surface protection film)

(Example 1)

3.125 parts by weight of a release agent containing a long-chain alkyl group-containing resin as a main component (the product name is "Tess Fine 303", manufactured by Hitachi Chemical Co., Ltd.), and 10 parts by weight of lithium bis (fluorosulfonyl) imide 10% ethyl acetate solution, 96.875 parts by weight of toluene and 50:50 mixed solvent of ethyl acetate, 0.09 parts by weight of catalyst (product name "Dryer 900", manufactured by Hitachi Chemical Co., Ltd.) The paint was formed by stirring and mixing to form the release agent layer of Example 1. The coating for the release agent layer of 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. Drying was performed in a hot-air loop-type oven at 120 ° C. for 1 minute, and a release film of Example 1 was obtained. On the other hand, 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate were copolymerized at a weight ratio of 100: 4, and 30 parts by weight of the obtained acrylate copolymer having a weight average molecular weight of 470,000 was dissolved in 70 parts by weight of ethyl acetate to obtain a binder (30% ethyl acetate solution with solid content), and 100 parts by weight of the binder was added and mixed with 1.2 parts by weight of an HDI-based curing agent (product name "Coronate ( , Registered trademark) HX ", manufactured by Nippon Polyurethane Industry Co., Ltd.) to form an application liquid, and apply the application liquid to a thickness of 38 μm so that the thickness after drying becomes 20 μm. The surface of the polyethylene terephthalate film was dried in a hot air loop oven at 100 ° C. for 2 minutes to form an adhesive layer. Then, the surface of the adhesive layer was bonded with the above The release agent layer (release agent-treated surface) of the release film of Example 1. The obtained adhesive film was kept at 40 ° C. for 5 days to cure the adhesive, thereby obtaining a surface protective film of Example 1. .

(Example 2)

8.33 parts by weight of a release agent containing a long-chain alkyl group-containing resin as a main component (product name: "Piroiru HT", manufactured by Fangyishe Oil Industry Co., Ltd.) and 10 parts by weight of bis (trifluoromethanesulfonium) A lithium imide 10% ethyl acetate solution, 91.67 parts by weight of toluene, and a 50:50 mixed solvent of ethyl acetate were mixed together and stirred to prepare a coating material for forming the release agent layer of Example 2. The coating for the release agent layer of Example 2 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. Drying was performed in a hot-air loop-type oven at 120 ° C. for 1 minute, and a release film of Example 2 was obtained. Except using the release film of Example 2 instead A protective film of Example 2 was obtained in the same manner as in Example 1 except for the release film of Example 1.

(Example 3)

1.5 parts by weight of a release agent containing a long-chain alkyl group-containing resin as a main component (product name: "Piroiru 1010S", manufactured by Fangyi Oil & Fat Industry Co., Ltd.) A lithium 10% ethyl acetate solution, 98.5 parts by weight of toluene, and a mixed solvent of ethyl acetate and isopropanol at a ratio of 50:40:10 were mixed together and stirred to prepare a coating for forming the release agent layer of Example 3. . The coating for the release agent layer of Example 3 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. Drying was performed in a hot-air loop-type oven at 120 ° C. for 1 minute, and a release film of Example 2 was obtained. A protective film of Example 3 was obtained in the same manner as in Example 1 except that the release film of Example 3 was used instead of the release film of Example 1.

(Comparative example 1)

A stripper containing 3.125 parts by weight of a resin containing a long-chain alkyl group as a main component (the product name is "Tess Fine 303", manufactured by Hitachi Chemical Co., Ltd.), and 96.875 parts by weight of toluene and ethyl acetate were 50:50. A mixed solvent and 0.09 parts by weight of a catalyst (product name: "Dryer 900", manufactured by Hitachi Chemical Co., Ltd.) were mixed together and stirred to prepare a coating material for forming a release agent layer of Comparative Example 1. The coating for 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. Drying was performed in a hot-air loop-type oven at 120 ° C. for 1 minute, and a release film of Example 1 was obtained. On the other hand, 5 parts by weight of lithium bis (fluorosulfonyl) imide 10% ethyl acetate was added to and mixed with 100 parts by weight of the binder (solid ethyl acetate solution having a solid content of 30%). Ester solution, 1.2 parts by weight of HDI-based curing agent (product name is "Coronate ( , Registered trademark) HX ", manufactured by Nippon Polyurethane Industry Co., Ltd.) to form an application liquid, and apply the application liquid to a thickness of 38 μm so that the thickness after drying becomes 20 μm. The surface of the polyethylene terephthalate film was dried in a hot air loop oven at 100 ° C. for 2 minutes to form an adhesive layer. Then, the surface of the adhesive layer was bonded with the above The release agent layer (polysiloxane-treated surface) of the produced release film of Comparative Example 1. The obtained adhesive film was held in an environment of 40 ° C. for 5 days to cure the adhesive, and Comparative Example 1 was obtained. Surface protective film.

(Comparative example 2)

A surface protection film of Comparative Example 2 was obtained in the same manner as in Example 3 except that lithium bis (fluorosulfonamido) imide was not added to the release agent layer.

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

<Method for measuring surface resistivity of release agent layer and adhesive layer>

Hiresta (manufactured by Mitsubishi Chemical Corporation) , Registered trademark) -UP, under the conditions of an applied voltage of 100 V and a measurement time of 30 seconds, the surface resistivity of the release agent layer of the release film and the surface resistivity of the adhesive layer of the surface protective film were measured. During the measurement, the surface resistivity A of the release agent layer of the sample after the individual release film (release film monomer) was kept at 40 ° C. for 5 days and etched was measured. Surface protection film (a surface protection film obtained by bonding an adhesive film and a release agent layer to a surface protection film at a temperature of 40 ° C. for 5 days to cure the adhesive). The surface resistivity B of the adhesive layer of the protective film and the surface resistivity C of the release agent layer of the release film.

<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 peel speed of 40 m per minute, a surface potentiometer (Keans Co., Ltd.) was used. (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 value. Off-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 (○) when there was no contaminated transition on the polarizing plate, and it was judged as (×) when there was contaminated transition on the polarizing plate.

The obtained surface protective films of Examples 1 to 3 and Comparative Examples 1 to 2 were measured, and the measurement results are shown in Table 1. Among them, "2EHA" refers to 2-ethylhexyl acrylate, "HEA" refers to 2-hydroxyethyl acrylate, "LiFSI" refers to lithium bis (fluorosulfonyl) imide, and "LiTFSI" refers to bis ( Trifluoromethanesulfonium sulfide) lithium imine, "303" means Tess Fine 303, "Dryer" means Dryer 900, and "HT" means Piroiru HT "1010S" means Piroiru 1010S.

In addition, the surface resistivity A refers to the surface resistivity (Ω / □) of the release agent surface of the release film after the release film (release film alone) is etched, and the surface resistivity B refers to the surface resistivity. Surface resistivity (Ω / □) of the adhesive surface of the surface protective film after the protective film is peeled off. The surface resistivity C refers to the surface resistivity of the release agent surface of the release film after peeling off the adhesive surface. (Ω / □). OR in the table is the abbreviation of “Over Range”, which means that the measurement range of the surface resistance meter (Hiresta-UP) is exceeded, which means that the surface resistivity is 1E + 13Ω / □ or more. In addition, the surface resistivity value is represented by the exponential notation method prescribed by JIS X 0210. For example, 3.9E + 8 is Refers to the 8th power of 3.9 × 10.

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

The surface protection films of Examples 1 to 3 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 surface protection film is peeled from the adherend. In addition, the surface resistivity of the release agent layer of the release film is 8.4E + 7 ~ 3.9E + 8Ω / □ when the release film (release film alone) is alone. The surface resistivity of the release agent layer of the release film adhered to the adhesive surface and peeled is outside the over range (1.0E + 13Ω / □ or more), compared with the surface of the adhesive surface The resistivity is reduced to 3.7E + 10 ~ 5.9E + 10Ω / □. From this, it can be seen that the antistatic agent has moved from the release agent to the adhesive surface.

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 no antistatic agent was used, although the contamination of the adherend was improved, the peeling static voltage when the surface protective film was peeled from the adherend was high.

[Industrial availability]

The surface protective 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, they are bonded to the optical components and the like. 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 the anti-peeling electrostatic properties do not change over time (will not change over time) and the Less pollution, can improve the yield of production steps, and has great industrial use value.

Claims (5)

A surface protection film is a surface protection film in which an adhesive layer is formed on one side of a substrate film made of a transparent resin, and a release film having a release agent layer is bonded to the adhesive layer. Wherein, the release film is formed by laminating a release agent layer on one side of a resin film, and the release agent layer includes a release agent containing a long-chain alkyl group-containing resin as a main component and does not react with the release agent. An antistatic agent, said antistatic agent is an alkali metal salt, and contains 5 to 100 parts by weight of the solid content relative to 100 parts by weight of the solid content of the release agent containing the long-chain alkyl group-containing resin as a main component. In the antistatic agent, the antistatic agent component is transferred from the release film to the surface of the adhesive layer to reduce the peeling static voltage when the adhesive layer is peeled from the adherend. The surface protective film according to item 1 of the scope of the patent application, wherein the adhesive layer is obtained by crosslinking a (meth) acrylate copolymer. The surface protective film according to item 1 or 2 of the scope of patent application, wherein the surface potential when peeled from the optical film as an adherend is +0.7 kV to -0.7 kV. The surface protective film according to item 1 or 2 of the scope of application for a patent, wherein a peeling force of the peeling film when peeling from the adhesive layer is 0.005 to 0.3 N / 50 mm. An optical component is bonded with the surface protective film according to any one of claims 1 to 4 of the scope of patent application.