TWI709489B - Surface-protective film and optical component attached with the same - Google Patents

Abstract

The present invention provides a surface-protective film for which foreign matter (lumps of paste) caused by the adhesive do not easily occur when cut, which has conformability (wettability) even for an optical film having an uneven surface, for which there is also little contamination of the adherend and for which the low contamination property of the adherend does not change over time, and which has excellent peeling antistatic performance that does not deteriorate over time, and an optical component attached with the same. In accordance with the present invention, in a surface-protective film 10 in which an adhesive layer 2 including a polyurethane-based adhesive is formed on one surface of a base film 1 including a transparent resin and a peeling film 5 having a release agent layer 4 is attached on the adhesive layer 2, the peeling film 5 has the release agent layer 4 containing a release agent and an antistatic agent that does not react with the release agent laminated on one surface of a resin film 3, a component of the antistatic agent is transferred to a surface of the adhesive layer 2 from the peeling film 5, and the peeling charge pressure is reduced when the adhesive layer 2 is peeled from the adherend.

Description

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

The present invention relates to a surface protection film bonded to optical components (hereinafter, sometimes referred to as "optical film") such as polarizing plates, phase difference plates, and lens films for displays. In more detail, to provide an optical film that hardly appears when foreign matter (glue block) caused by adhesives occurs during cutting and has unevenness on the surface. The conformability (wettability) is also good, and it is good for adhesion. The surface protective film that has less body pollution and low pollution to the adherend does not change over time. It also has a surface that has excellent anti-peeling and static electricity performance that does not deteriorate over time (does not deteriorate over time) A protective film and an optical component to which the surface protective film is bonded.

At present, when manufacturing and transporting optical films such as polarizing plates, phase difference plates, display lens films, anti-reflection films, hard coat films, transparent conductive films for touch panels, and optical products such as displays using them, pass A surface protection film is attached to the surface of the optical film to prevent surface contamination and scratches in the subsequent steps. In order to save the labor and time of peeling off the surface protection film and then attaching it to improve work efficiency, for the visual inspection of the optical film as a product, the surface protection film may also be attached to the optical film. State directly Shi.

In the past, in order to prevent the adhesion of scratches and dirt in the manufacturing process of optical products, a surface protective film in which an adhesive layer is provided on one side of a base film is generally used. The surface protection film is bonded to the optical film by a micro-adhesive adhesive layer. The reason for setting the adhesive layer to micro-adhesive force is that it can be easily peeled off when the used surface protective film is peeled from the surface of the optical film, and to prevent the adhesive from adhering and remaining on the adherend. The phenomenon on the optical film of the product (the so-called prevention of the occurrence of adhesive residue).

As a micro-adhesive adhesive, acrylic adhesives are mostly used. However, when the optical film is cut to a predetermined size according to the size of the display, the adhesive is broken under the cutting knife and is likely to produce small pieces of foreign matter ( Also known as "glue block") problem. If such a foreign matter is generated, it may cause problems such as step contamination, or being pressed on the optical film to produce marks. Therefore, there is a demand for a surface protection film that produces less foreign matter when tearing or cutting the optical film to which the surface protection film is bonded. In addition, it is also required to have good conformability (wettability) for optical films with uneven surfaces such as prism sheets, anti-glare treated polarizers, etc., and it is also required to bond surface protective films to optical films. A surface protection film that is difficult for bubbles to enter when on the film.

In this way, in response to the need for a surface protective film that is difficult to produce glue lump during tearing or cutting, and has a good adaptability to various optical films, a surface protective film using a polyurethane adhesive is adopted.

In addition, in recent years, in the production process of liquid crystal display panels, the surface protection film attached to the optical film is peeled off and removed. The peeling of the static voltage will destroy the circuit components such as the driver IC used to control the display screen of the liquid crystal display, and the orientation of the liquid crystal molecules will be damaged. Although the number of occurrences of these phenomena is small, 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 consequently the breakdown voltage of the driving IC also tends to decrease. Recently, it is required to control the stripping static voltage within the range of +0.7kV~-0.7kV.

In order to prevent defects caused by the high peeling static voltage when peeling the surface protective film from the optical film as the adherend, some people have proposed a surface protective film that contains an antistatic agent for reducing the peeling static voltage. Adhesive layer.

For example, Patent Document 1 discloses an antistatic adhesive composed of a polyurethane having an alkylene oxide chain, an ionic compound, and a trifunctional isocyanate compound. In addition, Patent Document 2 discloses a polyurethane adhesive composition for a surface protective film, which is characterized by containing at least one salt of an alkali metal salt and an alkaline earth metal salt of a super acid. In addition, Patent Document 3 discloses a bonding agent composition and a surface protective film using the bonding agent composition, wherein the bonding agent composition is composed of an ionic liquid containing a fluorine organic anion and a polyurethane having a number average molecular weight of 5000 or more. composition.

【Prior Technical Literature】 【Technical Literature】

[Patent Document 1] Japanese Patent Application Publication No. 2005-154491

[Patent Document 2] JP 2006-182794 A

[Patent Document 3] JP 2007-277484 A

In Patent Documents 1 to 3, an antistatic agent is added to the inside of the adhesive layer. However, the thicker the thickness of the adhesive layer, and as time elapses after being attached to the adherend, the more the antistatic agent moves from the adhesive layer to the adherend to which the surface protective film is attached. If the amount of the antistatic agent moved to the adherend is large, the appearance quality of the optical film as the adherend may decrease, or the adhesion properties of the surface protection film may change with time.

If the thickness of the adhesive is reduced in order to reduce the time-dependent change in the movement of the antistatic agent from the adhesive layer to the adherend, other problems will arise. For example, when used for an optical film with irregularities on the surface such as a polarizing plate that has been anti-glare treated for anti-glare, there is a problem that the adhesive cannot cater to (follow) the irregularities on the surface of the optical film and mix in bubbles, or , Due to the reduction of the bonding area between the optical film and the adhesive, the bonding force is reduced, and the surface protection film floats or peels during use.

The present invention has been completed in view of the above circumstances, and its subject is to provide a conformability (conformability) (lubricity) of an optical film that is hard to cause foreign matter (glue) due to adhesives during cutting and has irregularities on the surface. A surface protective film that has good wettability, less pollution to the adherend, and low pollution to the adherend that does not change over time. It also has a surface that has excellent anti-peeling and electrostatic performance without deterioration over time. A protective film and an optical component to which the surface protective film is bonded.

The inventors of the present invention conducted intensive research on this subject.

In order to reduce the pollution to the adherend and also reduce the time-dependent change in pollution, it is necessary to reduce the amount of antistatic agent that is presumed to cause pollution to the adherend. However, when the amount of the antistatic agent is reduced, the peeling static voltage when the surface protection film is peeled from the adherend becomes higher. The inventors of the present invention studied a method of lowering the peeling static voltage when peeling the surface protective film from the adherend without increasing the absolute amount of the antistatic agent.

As a result, it was found that instead of adding an antistatic agent to the bonding agent and mixing to form a bonding agent layer, a bonding agent composition containing no antistatic agent was coated and dried to laminate the bonding agent layer, and then the bonding agent layer The release film with the release agent layer containing the antistatic agent is bonded in contact with the release agent layer, and an appropriate amount of antistatic agent is transferred from the release film side to the surface of the adhesive layer, thereby obtaining a surface that can inhibit peeling The present invention has been completed based on the above-mentioned findings.

That is, the present invention provides a surface protection film in which a polyurethane-based adhesive layer is formed on one side of a base film composed of a resin having transparency, and a release agent layer is bonded to the adhesive layer The surface protection film of the release film, wherein the release film is formed by laminating a release agent layer on one side of the resin film, and the release agent layer includes a release agent and an antistatic agent that does not react with the release agent, and the antistatic The components of the electrostatic agent transfer from the peeling film to the surface of the adhesive layer, reducing the peeling static voltage when the adhesive layer is peeled from the adherend.

In addition, it is preferable that the antistatic agent is an ionic compound.

In addition, the antistatic agent is preferably an ionic compound having an alkali metal as a cation.

In addition, the surface potential when peeled from the optical film as an adherend is preferably +0.7 kV to -0.7 kV.

Preferably, the adhesive layer is formed by cross-linking a polyurethane-based adhesive.

Preferably, the peeling force when the peeling film is peeled off from the adhesive layer is 0.005 to 0.3 N/50 mm.

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 is a kind of optical film that is hard to appear due to foreign matter (glue block) caused by adhesive during cutting, and has good adaptability (wettability) with respect to the surface. The surface protective film that has less body pollution and low pollution to the adherend does not change over time is also a surface protective film that has excellent anti-peeling static electricity performance that does not deteriorate over time. The present invention also provides an optical component to which the surface protection film is bonded.

Based on the surface protection film of the present invention, the surface of the optical film can be reliably protected, and therefore the production efficiency and the yield can be improved.

1‧‧‧Base film

2‧‧‧Binder layer

3‧‧‧Resin film

4‧‧‧Release agent layer

5‧‧‧Peeling film

7‧‧‧Antistatic agent

8‧‧‧To be adhered (optical parts)

10‧‧‧Surface protective film

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

20‧‧‧Optical parts with surface protective film

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

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

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

[Forms of implementing the invention]

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

Fig. 1 is a cross-sectional view showing the concept of the surface protective film of the present invention. The surface protection film 10 has an adhesive layer 2 formed on one surface of a transparent base film 1. A release film 5 is bonded to 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 visual inspection of the optical component can be implemented in the state which bonded the surface protection film to the optical component as an adherend. A film made of a transparent resin used as the base film 1, preferably using polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate (polyethylene isophthalate) ), Polybutylene terephthalate and other polyester films. As this base film, what is necessary is just to have required intensity|strength and optical compatibility, and it is also possible to use the film comprised with other resin besides a 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 of the stretched film in the axial direction accompanying crystallization may be controlled to a 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, the thickness is preferably about 12 to 100 μm; if the thickness is about 20 to 50 μm, it is easy to handle, and therefore more Preferred.

In addition, if necessary, an antifouling layer for preventing surface contamination, an antistatic layer, a hard coat layer for preventing scratches, etc. may be provided on the surface of the base film 1 opposite to the surface on which the adhesive layer 2 is formed. . In addition, it can also be implemented on the surface of the base film 1. Surface modification by corona discharge, application of primer and other easy bonding treatments.

In addition, the adhesive layer 2 used in the surface protective film 10 of the present invention is adhered to the surface of the adherend, can be easily peeled off after use, and is difficult to contaminate the adhesive layer of the adherend. In addition, a polyurethane-based adhesive is preferable from the viewpoints that there are few glue bumps during cutting and good wettability to adherends such as optical films.

As a polyurethane binder, it is a polyurethane resin composed of a polyol component and a polyisocyanate component. It can be selected in consideration of adhesion, wettability, and contamination by adherends. There is no polyol component and polyisocyanate component. Special restrictions. The polyurethane resin may be used alone or in combination of two or more kinds.

Examples of polyol components include polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, castor oil-based polyols, and the like. These polyol components may be used alone or in combination of two or more kinds.

As the polyisocyanate component, aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate, a polymer of diisocyanate, etc. are used. These polyisocyanate components may be used alone or in combination of two or more kinds.

，註冊商標)SH-101、SH-101M、SP-205、SP-220(TOYOCHEM CO.,LTD.製造)；ARACOAT(

，註冊商標)FT100、FT200(荒川化學工業股份 有限公司製造)；UN1175、UN1176(大同化成工業股份有限公司製造)等。黏結劑層也可以是使聚氨酯類黏結劑交聯或固化而成。 As a commercially available product of polyurethane-based adhesives, CYABINE (

, Registered trademark) SH-101, SH-101M, SP-205, SP-220 (manufactured by TOYOCHEM CO., LTD.); ARACOAT (

, Registered trademark) FT100, FT200 (manufactured by Arakawa Chemical Industry Co., Ltd.); UN1175, UN1176 (manufactured by Datong Chemical Industry Co., Ltd.), etc. The adhesive layer may also be formed by crosslinking or curing a polyurethane-based adhesive.

The thickness of the adhesive layer 2 used in the surface protection film 10 of the present invention is not particularly limited. For example, it is preferably a thickness of about 5-40 μm, and more preferably a thickness of about 10-30 μm. When the peel strength (adhesive force) of the surface protective film to the surface of the adherend is about 0.03~0.3N/25mm, the adhesive layer 2 with micro-adhesive force, the operation when peeling the surface protective film from the adherend It is excellent in performance and therefore preferred. In addition, from the viewpoint of excellent workability when peeling off the peeling film 5 from the surface protective film 10, the peeling force of peeling off the peeling film 5 from the adhesive layer 2 is preferably under the conditions of a peeling speed of 0.3 m/min and a peeling angle of 180° The measurement is 0.005~0.3N/50mm.

In addition, 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. The release agent layer 4 contains a release agent and does not interact with the release agent. Reactive antistatic agent.

As the resin film 3, a polyester film, a polyamide film, a polyethylene film, a polypropylene film, a polyimide film, etc. can be cited. From the viewpoint of excellent transparency and relatively low cost, a polyester film is particularly preferred . The resin film may be an unstretched film, a uniaxially stretched film or a biaxially stretched film. In addition, the stretching ratio of the stretched film and the orientation angle of the stretched film in the axial direction accompanying crystallization may be controlled to a specific value.

The thickness of the resin film 3 is not particularly limited. For example, it is preferably a thickness of about 12 to 100 μm; if it is a thickness of about 20 to 50 μm, handling is easy, which is more preferable.

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

As the release agent constituting the release agent layer 4, a polysiloxane-based release agent, a long-chain alkyl group-containing release agent, a fluorine-based release agent, and the like can be mentioned.

As a silicone type release agent, well-known polysiloxane type release agents, such as an addition reaction type, a condensation reaction type, a cationic polymerization type, a radical polymerization type, etc. are mentioned. As commercially available products of addition reaction type polysiloxane-based release agents, for example, KS-776A, KS-847T, KS-779H, KS-837, KS-778, KS-830 (Shin-Etsu Chemical Industry Co., Ltd.); SRX-211, SRX-345, SRX-357, SD7333, SD7220, SD7223, LTC-300B, LTC-350G, LTC-310 (Dow Corning Toray Co., Ltd. (Dow Corning Toray Co. ,Ltd.) manufacturing) and so on. As a condensation reaction type commercially available product, for example, SRX-290, SYLOFF-23 (manufactured by Dow Corning Toray Co., Ltd.) and the like can be cited. Examples of commercially available cationic polymerization products include TPR-6501, TPR-6500, UV9300, UV9315, and UV9430 (manufactured by Momentive Performance Materials Inc.); X62-7622 (Shin-Etsu Chemical Industry Co., Ltd.) Co., Ltd.), etc. As a radical polymerization type commercially available product, for example, X62-7205 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be cited.

As a release agent containing a long-chain alkyl group-containing resin as the main component, there can be mentioned: long-chain alkyl-containing amino alkyd resin, long-chain alkyl-containing acrylic resin, long-chain aliphatic side group type resin (selection From the reaction between at least one active hydrogen-containing polymer among polyvinyl alcohol, ethylene/vinyl alcohol copolymer, polyethyleneimine, and hydroxyl-containing cellulose derivatives, and long-chain alkyl-containing isocyanate Products) and other known long-chain alkyl-containing release agents. It may be a release agent that adds a curing agent and an ultraviolet initiator to perform a curing reaction, or may be a release agent that is cured by volatilizing a solvent.

As the "long-chain alkyl group", an alkyl group having 8 to 30 carbon atoms is preferable, and the number of carbon atoms may be 10 or more, 12 or more, 18 or less, or 24 or less. Among them, a linear alkyl group is preferable. As specific examples, can be selected from decyl, undecyl, lauryl, dodecyl, tridecyl, myristyl, tetradecyl, pentadecyl, cetyl, palm One or two or more alkyl groups selected from the group consisting of hexadecyl, hexadecyl, heptadecyl, stearyl, octadecyl, nonadecyl, eicosyl, and behenyl.

，註冊商標)RA-30；一方社油脂工業股份有限公司製造的Piroiru(

，註冊商標)1010、Piroiru 1010S、Piroiru 1050、Piroiru HT；中京油脂股份有限公司製造的Resem N-137；花王股份有限公司製造的Exceparl(

，註冊商標)PS-MA；日立化成股份有限公司製造的Tess Fine(

，註冊商標)303等。 For products that are commercially available as long-chain alkyl-containing resin-based release agents, 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 manufactured by Zhongjing Oil Co., Ltd.; Exceparl (

, Registered trademark) PS-MA; Hitachi Chemical Co., Ltd. manufactured Tess Fine (

, Registered trademark) 303 and so on.

Examples of the fluorine-based release agent include a coating agent obtained by dispersing a perfluoroalkyl group-containing vinyl ether-based polymer, or a fluororesin such as tetrafluoroethylene, trifluoroethylene, and the like in a binder resin.

As the antistatic agent constituting the release agent layer 4, an antistatic agent that has good dispersibility in the release agent solution and does not hinder the curing of the release agent is preferable. In addition, in order to move from the release agent layer 4 to the surface of the adhesive layer 2, the adhesive layer is given For the antistatic effect, an antistatic agent that does not react with the release agent is preferable. As such an antistatic agent, an ionic compound is preferable.

The ionic compound is an ionic compound having a cation and an anion. Examples of the cation include alkali metal cations, pyridinium cations, imidazolium cations, pyrimidinium cations, pyrazolium cations, pyrrolium cations, and ammonium cations. Such as nitrogen-containing onium cations, phosphonium cations, sulfonium cations, etc. The nitrogen-containing onium cation may have an organic group such as an alkyl group and a substituent. It is preferably a quaternary nitrogen cation, and examples thereof include: 1-alkylpyridinium (carbon atoms at positions 2 to 6 may or may not have substituents), such as quaternary pyridinium cations, 1,3-dioxane Quaternary imidazolium cations such as the base imidazolium (the carbon atoms at positions 2, 4, and 5 may or may not have substituents), and N-alkylpyrimidinium (carbon atoms at positions 2 and 4-6 are both It may have or may not have substituents), such as quaternary pyrimidinium cations, 1,2-dialkylpyrazolium (carbon atoms at positions 3 to 5 may have or may not have substituents), etc. Quaternary pyrazolium cation, 1,1-dialkylpyrrolium (carbon atoms at positions 2 to 5 may or may not have substituents) and other quaternary pyrrolium cations, quaternary ammonium such as tetraalkylammonium Cation etc. Examples of phosphonium cations include phosphonium cations having organic groups such as tetraalkylphosphorus. Examples of sulfonium cations include sulfonium cations having organic groups such as trialkylaluminium.

Further, as the anion, include ^{_{C n H 2n + 1 COO -}} , C n F 2n + 1 COO -, NO 3 -, C n F 2n + 1 SO 3 -, (C n F 2n + 1 SO 2) _{^{2 N -, (C n F}} 2n + 1 SO 2) 3 C -, RC 6 H 4 SO 3 -, PO 4 3-, AlCl 4 -, Al 2 Cl 7 -, ClO 4 -, BF 4 -, PF _{^{6 -, AsF 6 -, SbF}} 6 -, SCN - and so on. These ionic compounds may be used alone or in mixture of two or more kinds. In order to stabilize the ionic substance, a compound containing a polyoxyalkylene structure may be added.

Among them, as the cation, an ionic compound (alkali metal salt) having an alkali metal cation is preferable. The alkali metal salt may include: lithium, sodium and potassium salts, specifically, for example, is preferably used by the Li ^+, Na ^+, K ⁺ and other cations and ^{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 ^- and other anions composed of metal salts. 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, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ ) ₃ C and other lithium salts. These alkali metal salts may be used alone or in combination of two or more kinds. In order to stabilize the ionic substance, a compound containing a polyoxyalkylene structure may be added.

The amount of antistatic agent added to the release agent varies according to the type of antistatic agent and the degree of affinity with the release agent, as long as the peeling static voltage required to peel the surface protective film from the adherend is considered , Just set the pollution and bonding characteristics of the adherend.

The mixing method of the release agent and the antistatic agent is not particularly limited. Any of the following mixing methods can be used: after adding an antistatic agent to the release agent for mixing, adding a catalyst for curing the release agent and mixing; after diluting the release agent with an organic solvent in advance, adding an antistatic agent and peeling A method of mixing a catalyst for curing the agent; a method of diluting the release agent with an organic solvent in advance, adding a catalyst and mixing, and then adding an antistatic agent and mixing. In addition, if necessary, materials that assist the antistatic effect such as adhesion promoters such as silane coupling agents and polyoxyalkylene-containing compounds may be added.

The mixing ratio of the release agent and the antistatic agent is not particularly limited, but it is preferable that the antistatic agent has a ratio of about 5 to 100 in terms of solid content relative to 100 solid content of the release agent. Relative to the solid content of the release agent 100, if the amount of antistatic agent added in terms of solid content is less than 5, the amount of antistatic agent transferred to the surface of the adhesive layer will also decrease, making it difficult to make the adhesive layer antistatic Function. In addition, with respect to the solid content of the release agent 100, if the addition amount of the antistatic agent in terms of solid content exceeds 100, the release agent will also be transferred to the surface of the adhesive layer together with the antistatic agent. Therefore, it may Will reduce the bonding properties of the adhesive layer.

In the present invention, 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 there is no particular limitation. Specifically, it can include: (1) a method of applying a resin composition for forming the adhesive layer 2 on one side of the base film 1 and drying to form the adhesive layer and then attaching the release film 5; (2) A method of applying and drying the resin composition for forming the adhesive layer 2 on the surface of the release film 5 to form the adhesive layer, and then bonding the base film 1 together. Either method can be used.

In addition, 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.

In addition, 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, Meeller bar coating, and air knife coating can be used.

For 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. In addition, 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. The surface potential can be adjusted by changing the type and amount of the antistatic agent contained in the release agent layer.

2 is a cross-sectional view showing a state after peeling off the release film 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. 1, a part of the antistatic agent (reference numeral 7) contained in the release agent layer 4 of the release film 5 is transferred (attached) to the surface Protect the surface of the adhesive layer 2 of the film 10. Therefore, in FIG. 2, the spots with reference numeral 7 schematically show the antistatic agent attached to the surface of the adhesive layer 2 of the surface protective film. When the components of the antistatic agent 7 are transferred from the peeling 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 is reduced. In addition, the peeling static voltage when peeling off the adhesive layer from the adherend can be measured by a known method. For example, after attaching a surface protection film to an adherend such as a polarizing plate, the surface is peeled off using a high-speed peeling tester (manufactured by TESTER Sangyo Co., Ltd.) at a peeling speed of 40m per minute While protecting the film, a surface potentiometer (manufactured by Keyence Corporation) was used to measure the surface potential of the adherend surface every 10 ms, and the maximum absolute value of the surface potential at this time was taken as the peeling static voltage ( kV) is measured.

For the surface protection film of the present invention, when the surface protection film shown in Figure 2 is peeled off When the surface protective film 11 in a film state is attached to the adherend, the antistatic agent transferred to the surface of the adhesive layer 2 comes into contact with the surface of the adherend. By this operation, the peeling static voltage when peeling off the surface protective film from the adherend again can be suppressed low.

Fig. 3 is a cross-sectional view showing an embodiment of the optical component of the present invention. In a state where the peeling film 5 is peeled off from the surface protection 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, the optical component 20 to which the surface protection film 10 of this invention was bonded is shown in FIG. As an optical component, optical films, such as a polarizing plate, a phase difference plate, a lens film, a polarizing plate also used as a phase difference plate, and a polarizing plate also used as a lens film, are mentioned. Such optical components are used as constituent components of liquid crystal display devices such as liquid crystal display panels and various optical system devices of measuring instruments. In addition, examples of optical components 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 and removed from the optical component (optical film) as the adherend, the peeling static voltage can be sufficiently suppressed to a low level. Therefore, without worrying about damaging circuit components such as driver ICs, TFT elements, gate line driver circuits, etc., it is possible to improve production efficiency in steps such as manufacturing liquid crystal display panels, and ensure the reliability of production steps.

[Example]

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

(Manufacture of surface protective film)

(Example 1)

Add 5 parts by weight of addition reaction type polysiloxane release agent (the product name is SRX-211, the non-volatile content of the release agent is 30% by weight, manufactured by Dow Corning Toray Co., Ltd.), 5 parts by weight 20% by weight ethyl acetate solution of lithium bis(fluorosulfonyl)imide, 90 parts by weight of toluene and ethyl acetate as a 1:1 mixed solvent, and 0.05 parts by weight of platinum catalyst (product name is SRX-212 Catalyst (manufactured by Dow Corning Toray Co., Ltd.) was mixed together and stirred and mixed to prepare a coating for forming the release agent layer of Example 1. Using a Meeller rod, the paint used to form the release agent layer of Example 1 was applied to the surface of a 38 μm thick polyethylene terephthalate film so that the thickness after drying became 0.2 μm. It was dried in a hot-air loop oven at 120°C for 1 minute to obtain a peeling film of Example 1. On the other hand, 100 parts by weight of polyurethane adhesive (product name "ARACOAT FT200", 40% by weight of non-volatile matter in the adhesive, manufactured by Arakawa Chemical Industry Co., Ltd.), 5.7 parts by weight of curing agent ( The product name is "ARACOAT CL2503", the non-volatile content of the curing agent is 40% by weight, manufactured by Arakawa Chemical Industry Co., Ltd.) and mixed to obtain a coating solution. The coating solution is dried so that the thickness after drying becomes 20μm After coating on the surface of a polyethylene terephthalate film with a thickness of 38 μm, it was dried in a hot-air loop oven at 100°C for 2 minutes to form an adhesive layer. Then, on the surface of the adhesive layer, the release agent layer (polysiloxane-treated surface) of the release film of Example 1 produced above was bonded. The resulting adhesive conjunctiva was kept at a temperature of 40° C. for 5 days to cure the adhesive, and the antistatic surface protective film of Example 1 was obtained.

(Example 2)

In addition to changing the antistatic agent to lithium bis(trifluoromethanesulfonate) imide, the Example 1 was operated in the same manner, and the protective film of Example 2 was obtained.

(Comparative example 1)

Add 5 parts by weight of addition reaction type polysiloxane release agent (product name is SRX-211, the content of non-volatile matter of the release agent is 30% by weight, manufactured by Dow Corning Toray Co., Ltd.), 95 parts by weight Toluene and ethyl acetate are a 1:1 mixed solvent, and 0.05 parts by weight of platinum catalyst (product name is SRX-212 Catalyst, manufactured by Dow Corning Toray Co., Ltd.) and mixed together and mixed to prepare Paint used to form the release agent layer of Comparative Example 1. Using a Meeller rod, the paint used to form the release agent layer of Comparative Example 1 was applied to the surface of a 38 μm-thick polyethylene terephthalate film so that the thickness after drying became 0.2 μm. It was dried in a hot-air circulating oven at 120° C. for 1 minute to obtain a release film of Comparative Example 1. On the other hand, 100 parts by weight of polyurethane adhesive (product name "ARACOAT FT200", 40% by weight of non-volatile matter in the adhesive, manufactured by Arakawa Chemical Industry Co., Ltd.), 5.7 parts by weight of curing agent ( The product name is "ARACOAT CL2503", the non-volatile content of the curing agent is 40% by weight, manufactured by Arakawa Chemical Industry Co., Ltd., and 20% by weight acetic acid mixed with 10 parts by weight of lithium bis(fluorosulfonyl)imide Ethyl solution, the mixed coating solution, so that the thickness after drying becomes 20μm, apply it to the surface of the polyethylene terephthalate film with a thickness of 38μm, and then circulate it in hot air at 100°C Dry for 2 minutes in a type oven to form an adhesive layer. Then, on the surface of the adhesive layer, the release agent layer (polysiloxane-treated surface) of the release film of Comparative Example 1 produced above was bonded. The obtained adhesive film was kept at a temperature of 40° C. for 5 days to cure the adhesive, and an antistatic surface protective film of Comparative Example 1 was obtained.

(Comparative example 2)

Except for not adding lithium bis(fluorosulfonyl)imide to the release agent layer, the same procedure as in Example 1 was carried out to obtain a surface protective film of Comparative Example 2.

The method and results of the evaluation test are shown below.

(Method for measuring the surface resistivity of the release agent layer and the adhesive layer)

，註冊商標)-UP，在外加電壓100V、測定時間30秒的條件下，測定了剝離膜的剝離劑層的表面電阻率和表面保護膜的黏結劑層的表面電阻率。測定了將單獨的剝離膜(剝離膜單體)在40℃環境下保溫5天而進行老化後的試樣的剝離劑層的表面電阻率；以及，將貼合了黏結劑層和剝離劑層而成的黏結膜在40℃環境下保溫5天後，從黏結膜上剝下剝離膜，並分別測定了黏結膜的黏結劑層的表面電阻率B和剝離膜的剝離劑層的表面電阻率C。 Use Hiresta manufactured by Mitsubishi Chemical Corporation (

, Registered trademark)-UP, under the conditions of an applied voltage of 100V 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. The surface resistivity 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 then aged was measured; and the adhesive layer and the release agent layer were bonded together After the resulting conjunctiva was kept at 40°C for 5 days, the peeling film was peeled off from the conjunctiva, and the surface resistivity B of the adhesive layer of the conjunctiva and the surface resistivity of the peeling agent layer of the peeling film were measured. C.

<Measurement method of peeling force of peeling film>

The sample of the surface protection film was cut to a size of 50 mm in width and 150 mm in length. In a test environment of 23℃×50%RH, the peeling film was peeled off 180° at a peeling speed of 300mm/min using a tensile testing machine, the strength at this time was measured, and this was used as the peeling force of the peeling film (N /50mm).

<Measurement method of adhesion of surface protective film>

The anti-glare and low-reflection treated polarizing plate (AG-LR polarizing plate) is laminated on the surface of the glass plate with a laminating machine. 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 of 23° C.×50% RH for one day. Then, use a tensile testing machine to move toward 180° at a peeling speed of 300mm/min. Peel off the surface protective film in the direction, measure the strength at this time, and use it as the adhesive force (N/25mm).

<Measurement method of peeling static voltage of surface protective film>

The anti-glare and low-reflection treated polarizing plate (AG-LR polarizing plate) is laminated on the surface of the glass plate with a laminating machine. 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 of 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 Co., Ltd.) (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 used as the peeling static voltage (kV).

<How to confirm the surface contamination of the surface protective film>

The anti-glare and low-reflection treated polarizing plate (AG-LR polarizing plate) is laminated on the surface of the glass plate with a laminating machine. Then, a surface protection film cut into a width of 25 mm was attached to the surface of the polarizing plate, and then stored in a test environment of 23° C.×50% RH for 3 days and 30 days. Then, the surface protection 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 the determination of surface contamination, it was judged as (○) when there was no contamination transfer on the polarizing plate, and it was judged as (×) when the contamination transfer on the polarizing plate was confirmed.

The obtained surface protective films of Examples 1 and 2 and Comparative Examples 1 and 2 were measured, and the measurement results are shown in Table 1. Among them, "FT200" refers to the non-volatile material of the binder contained in ARACOAT FT200, and "CL2503" refers to the non-volatile material of the curing agent contained in ARACOAT CL2503, "LiFSI" It refers to lithium bis(fluorosulfonyl)imide, "LiTFSI" refers to lithium bis(trifluoromethanesulfonyl)imide, "211" refers to the non-volatile substance of stripping agent contained in SRX-211, and "212" is Refers to SRX-212.

In addition, respectively, the surface resistivity A refers to the surface resistivity (Ω/□) of the peeling surface of the peeling film after aging a separate peeling film (peeling film monomer), and the surface resistivity B refers to the surface protective film The surface resistivity of the adhesive surface (Ω/□), and the surface resistivity C refers to the surface resistivity (Ω/□) of the peeling surface of the peeling film after peeling from the adhesive surface. OR in the table is the abbreviation of "Over Range", which means beyond the measuring range of the surface resistance meter (Hiresta-UP), meaning that the surface resistivity is 1E+13Ω/□ or more. In addition, the surface resistivity is expressed by the exponential notation method specified in JIS X 0210. For example, 4.9E+8 means 4.9×10 to the 8th power.

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

The surface protection films of Examples 1 to 2 of the present invention have appropriate adhesion strength, do not contaminate the surface of the adherend, and have low peeling static voltage when peeling the surface protection film from the adherend. In addition, the surface resistivity of the release agent layer of the release film is 4.9E+8~6.4E+8Ω/口 in the case of a separate release film, but the release agent layer of the release film after being bonded to the adhesive surface and peeled off The surface resistivity of the adhesive is out of the over range (above 1.0E+13). Compared with this, the surface resistivity of the adhesive surface is reduced to 7.8E+9~1.2E+10Ω/□. It can be seen that, The antistatic agent has moved from the release agent to the adhesive surface.

On the other hand, for the surface protective film of Comparative Example 1 in which an antistatic agent was added to the adhesive layer, although the peeling static voltage when the surface protective film was peeled from the adherend was low and good, the peeling Of pollution. In addition, in Comparative Example 2 in which no antistatic agent was used, although the contamination to the adherend was improved, the peeling static voltage when the surface protective film was peeled from the adherend was high.

【Industrial Utilization】

The surface protection film of the present invention can be applied to, for example, optical films such as polarizers, phase difference plates, lens films, etc., and can be used by bonding to the optical components in the production steps of various optical components, etc. To protect its surface. In addition, the surface protective film of the present invention can reduce the amount of static electricity generated when peeling from the adherend, and the anti-peeling electrostatic performance has little change with time (does not change with the passage of time). With less pollution, it can improve the yield of production steps, and has great industrial use value.

1‧‧‧Base film

2‧‧‧Binder layer

3‧‧‧Resin film

4‧‧‧Release agent layer

5‧‧‧Peeling film

7‧‧‧Antistatic agent

10‧‧‧Surface protective film

Claims (5)

A surface protection film in which a polyurethane-based adhesive layer is formed on one side of a base film made of a transparent resin, and the surface of the release film with a release agent layer is bonded to the adhesive layer A protective film, wherein the release film is formed by laminating a release agent layer on one side of a resin film, the release agent layer includes a release agent and an antistatic agent that does not react with the release agent, and the antistatic agent is An ionic compound with an alkali metal as a cation, the adhesive layer does not contain an antistatic agent, and the release agent layer contains 5 to 100 parts by weight relative to 100 parts by weight of the solid content of the release agent. In the antistatic agent, the components of the antistatic agent are 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 protection film described in the first item of the scope of patent application, wherein the adhesive layer is formed by cross-linking a polyurethane-based adhesive. The surface protection film described in the first or second item of the scope of patent application, wherein the surface potential when peeled from the optical film as the adherend is +0.7kV~-0.7kV. The surface protection film according to item 1 or 2 of the scope of patent application, wherein the peeling force of the peeling film when peeling from the adhesive layer is 0.005 to 0.3 N/50 mm. An optical component, which is laminated with the surface protection film described in any one of items 1 to 4 in the scope of the patent application.

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