TWI716475B - Surface-protective film and optical component attached with the same - Google Patents

Abstract

The present invention provides a surface-protective film and an optical component of using the same. The surface-protective film can be used for an optical film with a non-planar surface. Also, the surface-protective film causes less contamination to the adherend, which does not change over time. Further, the surface-protective film has excellent antistatic performance upon peeling which does not degrade over time. The surface-protective film (10) is formed by applying a release film (5) with a release agent layer (4) on an adhesive layer (2). The release film (5) is formed by laminating the release agent layer (4) on one side of a resin film (3). The release agent layer (4) includes: a release agent with dimethyl polysiloxane as the main component, an antistatic agent which does not react with the release agent, and an ester plasticizer containing at least one ether bond. The antistatic agent is an ionic compound with a melting point of 30~80℃. The antistatic agent and the ester plasticizer are transferred from the release agent layer (4) of the release film (5) to the surface of the adhesive layer (2), thereby reducing the electrostatic voltage when the adhesive layer (2) is peeled off from the adherend.

Description

Surface protection film and optical components with the film

The present invention relates to a surface protection film bonded to the surface of an optical component (hereinafter also referred to as an optical film) such as a polarizing plate, a retardation plate, and a lens film used for a display. In more detail, to provide a surface protective film with less contamination to an adherend, and further, to provide a surface protective film with excellent anti-peeling static electricity performance that deteriorates over time, and an optical component using the surface protective film .

In the past, in the manufacture and transportation of polarizers, retardation plates, lens films for displays, anti-reflection films, hard coat films, transparent conductive films for touch panels, and other optical films, as well as optical films such as displays using these films In the case of products, a surface protection film is attached to the surface of the optical film to prevent dirt or scratches on the surface in the subsequent process. Regarding the appearance inspection of the optical film as an optical product, in order to save the time of peeling off the surface protective film and re-adhesive, and to improve work efficiency, the surface protective film may be directly carried out in the state of bonding the surface protective film to the optical film.

Generally, in the preparation process of optical products, in order to prevent the adhesion of scratches or dirt, a surface protector with an adhesive layer on one side of the base film is used. Protective film. The surface protection film is bonded to the optical film via a micro-adhesive adhesive layer. The reason for making the adhesive layer micro-adhesive is that when the used surface protective film is peeled and removed from the surface of the optical film, it can be easily peeled off and the adhesive does not adhere and remain (that is, prevent the generation of glue residue) On the optical film that is the product of the adherend.

In recent years, in the production process of liquid crystal display panels, although the number of pieces generated is small, the peeling static voltage generated when the surface protective film bonded to the optical film is peeled and removed, which is used for control A phenomenon in which circuit components such as the driver IC of the display screen of a liquid crystal display panel are destroyed, or the orientation of liquid crystal molecules is impaired.

In addition, in order to reduce the power consumption of the liquid crystal display panel, the driving voltage of the liquid crystal material is lowered, and with this, the breakdown voltage of the driving IC is also lowered. Recently, it is required to make the peeling static voltage within the range of +0.7kV~-0.7kV.

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

In addition, in some liquid crystal panel manufacturers, as a method for evaluating the contamination of the surface protective film on the adherend, the following method is adopted: by temporarily peeling off the surface protective film attached to an optical film such as a polarizer, Laminate again in the state, and heat it under the specified conditions, then peel off the sheet It is a method of applying a protective film and observing the surface of the adherend. In this evaluation method, even if the surface contamination of the adherend is slight, there is a difference in the surface contamination of the adherend between the part where air bubbles are mixed and the part in contact with the adhesive of the surface protection film, then The surface contamination of the adherend remains in the form of traces of bubbles (sometimes called bubble penetration). Therefore, as an evaluation method for the contamination of the adherend surface, this evaluation method is a very strict evaluation method. In recent years, there has been a demand for a surface protective film that does not pose a problem in terms of contamination to the surface of the adherend even in the result of determination by such a strict evaluation method.

When peeling the surface protection film from the optical film as the adherend, in order to prevent the occurrence of defects caused by the high peeling static voltage, some people have proposed a method for suppressing the peeling static voltage. The surface protective film of the adhesive layer of the antistatic agent.

For example, Patent Document 1 discloses a surface protection film using an adhesive composed of an alkyltrimethylammonium salt, a hydroxyl group-containing acrylic polymer, and 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 adhesive sheets using the adhesive 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 anionic adsorptive compound, and a surface protection using the adhesive composition membrane.

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

In addition, Patent Document 5 discloses an adhesive composition and an adhesive sheet for a surface protection sheet of an optical member made of a polymer containing a liquid ionic salt.

【Existing technical documents】 【Patent Literature】

[Patent Document 1] JP 2005-131957 A

[Patent Document 2] JP 2005-330464 A

[Patent Document 3] Japanese Patent Application Publication No. 2005-314476

[Patent Document 4] JP 2006-152235 A

[Patent Document 5] JP 2008-069261 A

In the aforementioned Patent Documents 1 to 5, an antistatic agent is added to the inside of the adhesive layer. However, the thicker the adhesive layer, or the longer the time elapsed after it is attached to the adherend, the antistatic agent will transfer from the adhesive layer to the adherend compared to the adherend with the surface protective film. The more the amount. If the amount of the antistatic agent transferred to the adherend increases, the appearance quality of the optical film as the adherend may decrease, and the adhesiveness of the FPR film may decrease when the FPR film is bonded.

If the thickness of the adhesive layer is reduced in order to reduce the increase over time of the antistatic agent transferred from the adhesive layer to the adherend, other problems will arise. For example, when it is used for optical films having uneven surfaces such as polarizers that have been anti-glare treated for anti-glare, there is the following problem: the adhesive layer is difficult to follow. Air bubbles are mixed with the irregularities on the surface of the optical film, and the adhesive force decreases due to the decrease of the adhesion area between the optical film and the adhesive layer, and the surface protective film floats or falls off during use.

Therefore, there is a need for a surface protective film for optical films that can be bonded to optical films with uneven surfaces, has very little contamination on the adherend, and does not increase the contamination on the adherend even with time. In addition, there is a need for a surface protection film that can lower the peeling static voltage when the surface protection film is peeled from the adherend.

The inventors of the present application have conducted intensive research in order to solve these problems.

In order to reduce the contamination of the adherend and the increase in contamination over time, it is necessary to reduce the amount of the antistatic agent component in the adhesive layer that is presumed to be the cause of the contamination of the adherend. However, when the amount of the antistatic agent component in the adhesive layer is reduced, the peeling static voltage when the surface protective film is peeled from the adherend increases. Therefore, a method that can suppress the peeling static voltage when peeling the surface protective film from the adherend at a low level without increasing the absolute amount of the antistatic agent component in the adhesive layer has been studied.

As a result, it was found that by coating and drying an adhesive composition containing no antistatic agent to form an adhesive layer, only an appropriate amount of antistatic agent component is provided on the surface of the adhesive layer, not on the substrate The adhesive composition containing an antistatic agent is coated on one side of the film and dried to form an adhesive layer, which can reduce the peeling static voltage when peeling the surface protective film from the optical film as the adherend Thus, the present invention has been completed.

The present invention is made in view of the above situation, and its purpose is to provide Provides an optical film with uneven surface that can also be laminated, has less pollution to the adherend, and has low pollution to the adherend. It does not change even with time, and has excellent resistance to deterioration with time. It peels off the surface protective film with electrostatic performance and the optical component using the surface protective film.

In order to solve the above-mentioned technical problems, the inventive concept of the present invention is that the surface protection film of the present invention coats and dries and laminates an adhesive layer without an antistatic agent on one side of the substrate film. An appropriate amount of antistatic agent is provided on the surface of the adhesive layer to lower the contamination to the adherend and at the same time lower the peeling static voltage when peeling off the optical film as the adherend.

In order to solve the above-mentioned technical problems, the present invention provides a surface protection film by forming an adhesive layer on one surface of a base film made of a transparent resin, and laminating a release agent on the adhesive layer A layer of release film, characterized in that the release film is formed by laminating a release agent layer on one side of a resin film, wherein the release agent layer contains a release agent mainly composed of polydimethylsiloxane , An antistatic agent that does not react with the release agent, and an ester plasticizer containing at least one ether bond, the antistatic agent component is an ionic compound with a melting point of 30 to 80°C, the antistatic agent component Transfer with the ester plasticizer from the release agent layer of the release film to the surface of the adhesive layer, thereby reducing the peeling static voltage when the adhesive layer is peeled from the adherend .

In addition, the adhesive layer is preferably formed by crosslinking an adhesive composition containing a (meth)acrylate copolymer and a crosslinking agent.

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

In addition, the present invention provides an optical component formed by bonding the above-mentioned surface protection film.

The surface protective film of the present invention has less contamination to the adherend, and the low contamination to the adherend does not change even with time. In addition, the surface protection film of the present invention can be used even if the adherend is an optical film having irregularities on the surface of an AG polarizing plate or the like. In addition, according to the present invention, it is possible to provide a surface protective film with excellent anti-peeling static electricity performance that is not degraded over time, can lower the peeling static voltage generated when peeling from the optical film as an adherend, And an optical component using the surface protection film.

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

1‧‧‧Base film

2‧‧‧Adhesive layer

3‧‧‧Resin film

4‧‧‧Release agent layer

5‧‧‧Peeling film

7‧‧‧Antistatic agent and ester plasticizer

8‧‧‧Adhesive (optical parts)

10‧‧‧Surface protective film

11‧‧‧Peel off the surface protective film of the release film

20‧‧‧Optical parts with surface protective film attached

Fig. 1 is a schematic diagram showing the concept of the surface protection film of the present invention.

Fig. 2 is a cross-sectional view showing a state after peeling the release film 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.

The present invention will be described in detail below through embodiments.

Fig. 1 is a schematic diagram showing the concept of the surface protection film of the present invention. The surface protection film 10 has an adhesive layer 2 formed on the surface of one surface of the transparent base film 1. On the surface of the adhesive layer 2, the resin film 3 is laminated with The release film 5 of the release agent layer 4.

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, it is possible to perform the appearance inspection of the optical component in a state where the surface protection film is bonded to the optical component as an adherend. The film composed of a transparent resin used as the base film 1, suitable for use is polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and polyethylene terephthalate. Polyester films such as butylene terephthalate. In addition to polyester films, films made of other resins can also be used as long as they have the required strength and optical compatibility. The base film 1 may be a non-stretched film, or a uniaxially or biaxially stretched film. In addition, the stretching magnification of the stretched film or the orientation angle in the axial direction formed with the crystallization of the stretched film 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, but for example, a thickness of about 12 to 100 μm is preferable, and a thickness of about 20 to 50 μm is easier to handle, so it is more preferable .

In addition, if necessary, an antifouling layer for preventing surface fouling, 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, the surface of the base film 1 may be subjected to surface modification by corona discharge, application of an anchoring agent, and other easy adhesion treatments.

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

As the (meth)acrylate copolymer, the main monomers such as n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, etc. are combined with acrylonitrile, vinyl acetate, and methyl acrylate. Comonomers such as methyl acrylate and ethyl acrylate, functional monomers such as acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxybutyl acrylate, glycidyl methacrylate, N-methylolmethacrylamide, etc. It is a copolymer of polyoxyalkylene-containing monomers such as methoxy polyethylene glycol methacrylate. (Meth) acrylate copolymer, its main monomer and other monomers can be (meth) acrylate, as a monomer other than the main monomer, it can also contain one or more than (meth) Monomers other than acrylate. Other monomers other than the main monomer can be selected from, but are not particularly limited to, the aforementioned comonomers, functional monomers, polyoxyalkylene-containing monomers, and the like.

As the curing agent added to the adhesive layer 2, a crosslinking agent for crosslinking the (meth)acrylate copolymer includes isocyanate compounds, epoxy compounds, melamine compounds, metal chelate compounds, and the like. In addition, examples of the thickener include rosins, coumarone-indenes, terpenes, petroleum, phenols, and the like.

The thickness of the adhesive layer 2 used in the surface protective film 10 of the present invention is not particularly limited, but is preferably about 5 to 40 μm in thickness, and more preferably about 10 to 30 μm in thickness. In addition, since the workability when peeling the surface protective film from the adherend is excellent, it is preferable that the peel strength (adhesive force) of the surface protective film to the surface of the adherend is about 0.03~0.3N/25mm with micro adhesive force. Adhesive layer 2. In addition, since the workability when peeling off the peeling film 5 from the surface protective film 10 is excellent, the peeling force when peeling off the peeling film 5 from the adhesive layer 2 is preferably 0.2 N/50 mm or less, more preferably 0.14 N/50 mm or less.

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. The release agent layer 4 contains polydimethylsiloxane as the main component. A release agent, an antistatic agent that does not react with the release agent, and an ester plasticizer containing at least one ether bond. In the release film used in the surface protection film of the present invention, the antistatic agent component is preferably an ionic compound having a melting point of 30 to 80°C.

As the resin film 3, a polyester film, a polyamide film, a polyethylene film, a polypropylene film, a polyimide film, etc. can be mentioned. Since it has excellent transparency and low price, a polyester film is particularly preferred. The resin film may be an unstretched film, or a uniaxially or biaxially stretched film. In addition, the stretching magnification of the stretched film and the orientation angle in the axial direction formed with the crystallization of the stretched film can be controlled to specific values.

The thickness of the resin film 3 is not particularly limited, but for example, a thickness of about 12 to 100 μm is preferable, and a thickness of about 16 to 50 μm is easier to handle, which is more preferable.

In addition, the surface of the resin film 3 may be subjected to surface modification by corona discharge, application of an anchoring agent, and other easy adhesion treatments as needed.

Examples of the release agent comprising polydimethylsiloxane as the main component of the release agent layer 4 include well-known silicone release agents such as addition reaction type, condensation reaction type, cationic polymerization type, and radical polymerization type. . The products of the addition reaction type silicone stripper sold on the market, for example, include KS-776A, KS-847T, KS-779H, KS-837, KS-778, KS-830 (Shin-Etsu Chemical Co., Ltd. ) Manufacturing), SRX-211, SRX-345, SRX-357, SD7333, SD7220, SD7223, LTC-300B, LTC-350G, LTC-310 (manufactured by Dow Corning Toray Co., Ltd.), etc. Condensation reaction type silicone peeling on the market Examples of products of the release agent include SRX-290 and SYLOFF-23 (manufactured by Dow Corning Toray Co., Ltd.). Products of cationic polymerized silicone release agents sold on the market include, for example, TPR-6501, TPR-6500, UV9300, VU9315, UV9430 (manufactured by Momentive Performance Materials Company), and X62-7622 (Shin-Etsu Chemical Co., Ltd.) Stock) manufacturing) etc. The free radical polymerization type silicone release agent products sold on the market include X62-7205 (manufactured by Shin-Etsu Chemical Co., Ltd.).

As the antistatic agent constituting the release agent layer 4, it is preferable that the dispersibility with respect to the release agent solution containing polydimethylsiloxane as the main component is good, and does not hinder those with polydimethylsiloxane as the main component. Cured antistatic agent for release agent. In addition, in order to transfer from the release agent layer 4 to the surface of the adhesive layer 2 and impart an antistatic effect to the adhesive layer 2, an antistatic agent that does not react with a release agent mainly composed of polydimethylsiloxane is preferable. Ionic compounds with a melting point of 30 to 80°C are very suitable as such antistatic agents.

The ionic compound having a melting point of 30 to 80°C is an ionic compound having a cation and an anion. Examples of the cation include pyridine cation, imidazole cation, pyrimidine cation, pyrazole cation, pyrrolidinium cation, ammonium cation, etc. nitrogen cation and phosphonium cation, sulfonium cation cation, the anion is hexafluorophosphate (PF ₆ ^-), thiocyanate (SCN ^-), alkylbenzenesulfonates ^{_{(RC 6 H 4 SO 3 -}} ), , tetrafluoroborate (BF ₄ ^-) or a compound of organic and inorganic anions ^- ₍₄ ClO) perchlorate. By selecting the chain length of the alkyl group or the position and number of the substituents, an ionic compound with a melting point of 30 to 80°C can be obtained. The cation is preferably a quaternary nitrogen-containing onium cation, and examples thereof include quaternary pyridine cations such as 1-alkylpyridine (the carbon atoms at positions 2 to 6 may have or may not be substituted.), or 1,3-dioxane Quaternary imidazole cations such as quaternary imidazoles (the carbon atoms at positions 2, 4, and 5 may have or may not be substituted.), quaternary ammonium cations such as tetraalkylammonium, etc.

The amount of the antistatic agent added to the release agent whose main component is polydimethylsiloxane varies depending on the type of antistatic agent or the affinity with the release agent. The amount of antistatic agent added can be set in consideration of the expected peeling static voltage when peeling the surface protective film from the adherend, the contamination to the adherend, and the adhesion characteristics.

The ester plasticizer containing at least one ether bond constituting the release agent layer 4 is used to improve the antistatic performance of the surface of the adhesive layer 2. The plasticizer contained in the release agent layer 4 is preferably a plasticizer with good dispersibility to a release agent solution containing polydimethylsiloxane as a main component. In addition, a plasticizer that does not hinder the curing of the release agent whose main component is polydimethylsiloxane is preferable. In addition, the plasticizer plays a role of assisting the transfer of the antistatic agent contained in the release agent layer 4 from the release agent layer 4 to the surface of the adhesive layer 2. Therefore, the plasticizer is preferably one that does not react with the release agent whose main component is polydimethylsiloxane. As such a plasticizer, an ester plasticizer containing at least one ether bond in the molecule is suitable.

At least one ether bond existing in the molecule in the ester plasticizer is required to increase the affinity with the antistatic agent. In addition, in the surface protection film of the present invention, when the release agent layer is in contact with the adhesive layer, a plasticizer is used in order to efficiently transfer the antistatic agent component from the release agent layer to the surface of the adhesive layer. . In the present invention, in order to increase the affinity between the release agent layer and the adhesive layer, a plasticizer containing an ester group is suitably used.

As an ester plasticizer containing at least one ether bond in the molecule The agent includes, for example, diethylene glycol di-2-ethylhexanoate, tetraethylene glycol di-2-ethylhexanoate, hexaethylene glycol di-2-ethylhexanoate, triethylhexanoate Glycol diethyl butyrate, polyethylene glycol diethyl butyrate, polypropylene glycol diethylhexanoate, triethylene glycol dibenzoate, tetraethylene glycol dibenzoate, poly Ethylene glycol dibenzoate, polypropylene glycol dibenzoate, or polyethylene glycol-2-ethylhexanoic acid benzoate, etc. One type or two or more types can be selected from these ester plasticizer groups and used. Here, ethyl hexanoate is also called ethylhexanoate, ethylhexoate, ethyl hexane acid ester, and the like. Benzoate (benzoate) refers to benzoate.

The amount of ester plasticizer added to the release agent with polydimethylsiloxane as the main component varies depending on the type of plasticizer and the affinity with the release agent, but it can be considered from the adherend Set the desired peeling static voltage when peeling off the surface protective film, the pollution to the adherend, and the adhesion characteristics.

There is no particular limitation on the mixing method between the release agent containing polydimethylsiloxane as the main component, the antistatic agent and the ester plasticizer. Any of the following methods can be used: a method of adding and mixing an antistatic agent and an ester plasticizer to a release agent with polydimethylsiloxane as the main component, and then adding and mixing a catalyst for curing the release agent; using organic After the solvent predilutes the release agent with polydimethylsiloxane as the main component, the method of adding and mixing antistatic agent, ester plasticizer and the catalyst for curing of the release agent; will use polydimethylsiloxane as The main component of the release agent is diluted in an organic solvent in advance, the catalyst is added and mixed, and then the antistatic agent and ester plasticizer are added and mixed. In addition, if necessary, an adhesion improving agent such as a silane coupling agent, or a material that assists an antistatic effect such as a polyoxyalkylene group-containing compound may be added.

The mixing ratio of the release agent with polydimethylsiloxane as the main component, the antistatic agent and the ester plasticizer is not particularly limited, but it is relative to the release agent with polydimethylsiloxane as the main component. The solid content is 100 parts, and the total of the antistatic agent and the ester plasticizer based on the solid content is preferably a ratio of about 5 to 100 parts. Relative to 100 parts of the solid content of the release agent with polydimethylsiloxane as the main component, if the total amount of the antistatic agent and the ester plasticizer converted into the solid content is less than 5 parts, then The transfer amount of the antistatic agent and the ester plasticizer to the surface of the adhesive layer is reduced, and it is difficult to exert the antistatic function imparted to the adhesive. In addition, relative to 100 parts of the solid content of the release agent with polydimethylsiloxane as the main component, if the total amount of the antistatic agent and the ester plasticizer converted into the solid content exceeds 100 parts , The antistatic agent and ester plasticizer and the release agent with polydimethylsiloxane as the main component are also transferred to the surface of the adhesive layer at the same time, so the adhesive properties of the adhesive may be reduced.

The method of forming the adhesive layer 2 on the base film 1 of the surface protection film 10 of this invention, and the method of bonding the release film 5 can be performed by a well-known method, and it is not specifically limited. Specifically, the following methods can be cited: (1) The resin composition for forming the adhesive layer 2 is coated on one side of the base film 1, and dried to form the adhesive layer, and then the release film 5 is laminated Method; (2) The resin composition used to form the adhesive layer 2 is coated on the surface of the release film 5 and dried to form the adhesive layer, and then the method of laminating the base film 1, etc., use any of them The method can be.

In addition, the method of forming the adhesive layer 2 on the surface of the base film 1 may be a known method. Specifically, reverse coating, knife coating, gravure coating, slit extrusion coating, Meyer bar coating, air knife coating can be used. Known coating methods such as cloth.

In addition, in the same manner, the release agent layer 4 may be formed on the resin film 3 by using a known method. Specifically, well-known coating methods such as gravure coating, Meyer bar coating, and air knife coating can be used.

The surface protective film 10 of the present invention having the above-mentioned structure preferably has a surface potential of +0.7 kV to -0.7 kV when the adhesive layer is peeled from the optical film as an adherend. Furthermore, the surface potential is more preferably +0.5kV to -0.5kV, particularly preferably +0.1kV to -0.1kV. The surface potential can be adjusted by adding or subtracting the types and addition amount of the antistatic agent and ester plasticizer contained in the release agent layer.

Fig. 2 is a cross-sectional view showing a state after peeling a release film from the surface protection film of the present invention.

By peeling off the release film 5 from the surface protection film 10 shown in FIG. 1, part of the antistatic agent and ester plasticizer (reference numeral 7) contained in the release agent layer 4 of the release film 5 is transferred It is printed (attached) to the surface of the adhesive layer 2 of the surface protective film 10. Therefore, in FIG. 2, the antistatic agent and the ester plasticizer transferred on the surface of the adhesive layer 2 of the surface protective film 11 in the state where the release film is peeled off are indicated by the spots of reference numeral 7. By transferring the components 7 of the antistatic agent and the ester plasticizer from the release film 5 to the surface of the adhesive layer 2, the adhesive layer 2 is removed from the adherend as compared with the adhesive layer 2 before the transfer. The peeling static voltage during peeling decreases. In addition, the peeling static voltage when peeling the adhesive layer from the adherend can be measured by a known method. For example, after attaching the surface protective film to the adherend such as polarizer, use a high-speed peel tester (manufactured by TESTER SANGYO CO,. LTD.) to peel the surface protective film at a peeling speed of 40m per minute while using the surface potential A meter (manufactured by KEYENCE CORPORATION) measures the surface potential of the surface of the adherend every 10 ms, and uses the maximum absolute value of the surface potential at this time as the peeling static voltage (kV).

In the surface protection film of the present invention, when the surface protection film 11 in the state where the release film is peeled off as shown in FIG. 2 is attached to the adherend, the antistatic film is transferred to the surface of the adhesive layer 2 Agents and ester plasticizers are in contact with the surface of the adherend. Thereby, the peeling static voltage when peeling the surface protection 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.

The release film 5 is peeled from the surface protection film 10 of the present invention, and the adhesive layer 2 is exposed, and is bonded to the optical component 8 as the adherend via the adhesive layer 2.

That is, Fig. 3 shows an optical component 20 to which the surface protection film 11 of the present invention is bonded. Examples of optical components include optical films such as a polarizing plate, a retardation plate, a lens film, a polarizing plate that also serves as a retardation plate, and a polarizing plate that also serves as a lens film. The above-mentioned optical components can be used as constituent components of liquid crystal display devices such as liquid crystal display panels, optical system devices of various measuring instruments, and the like. In addition, examples of optical components include optical films such as anti-reflection 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 11 is peeled and removed from the optical component (optical film) as an adherend, the static voltage for suppressing peeling can be sufficiently low. Therefore, there is no need to worry about damaging circuit components such as driver ICs, TFT elements, gate line driver circuits, etc., and the production efficiency in the manufacturing process of liquid crystal display panels can be improved, and the reliability of the production process can be maintained.

[Example]

Next, the present invention will be further explained based on the embodiments.

(Example 1) (Production of surface protective film)

5 parts by weight of addition reaction type silicone (manufactured by Dow Corning Toray Co., Ltd., trade name: SRX-345), and 0.75 parts by weight of N-butyl-4 as an ionic compound with a melting point of 48°C -Picoline hexafluorophosphate, 0.75 parts by weight of tetraethylene glycol di-2-ethylhexanoate, 95 parts by weight of toluene and ethyl acetate as a 1:1 mixed solvent, 0.05 parts by weight of platinum catalyst (Manufactured by Dow Corning Toray Co., Ltd., trade name: SRX-212) was mixed, stirred and mixed to prepare a paint for forming the release agent layer of Example 1. The coating used to form the release agent layer of Example 1 was coated on the surface of a polyethylene terephthalate film with 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 oven for 1 minute, and the peeling film of Example 1 was obtained. On the other hand, relative to the copolymerization of 90 parts by weight of 2-ethylhexyl acrylate, 7 parts by weight of methoxy polyethylene glycol (400) methacrylate, and 3 parts by weight of 2-hydroxyethyl acrylate 100 parts by weight of the 30% ethyl acetate solution of the adhesive polymer composed of the material, stirring and mixing 1.2 parts by weight of the isocyanate curing agent (manufactured by TOSOH CORPORATION, trade name: CORONATE (registered trademark) HX), preparation example 1 The adhesive composition. In addition, CORONATE (registered trademark) HX is a curing agent of the HDI type (hexamethylene diisocyanate type).

After coating the adhesive composition of Example 1 on the surface of a polyethylene terephthalate film with a thickness of 38 μm so that the thickness after drying is 20 μm, it was dried in a hot air circulation oven at 100°C 2 minutes to form an adhesive layer. Of After that, on the surface of the adhesive layer, the release film of Example 1 prepared above was bonded via a release agent layer (silicone-treated surface). The obtained adhesive film was kept at a temperature of 40° C. for 5 days to cure the adhesive layer to obtain the surface protective film of Example 1.

(Example 2)

Except that instead of N-butyl-4-methylpyridine hexafluorophosphate, 1-methyl-3-ethylimidazole hexafluorophosphate, which is an ionic compound with a melting point of 62°C, was used, it was the same as Example 1 Ground, the surface protection film of Example 2 was obtained.

(Comparative example 1)

5 parts by weight of addition reaction type silicone (manufactured by Dow Corning Toray Co., Ltd., trade name: SRX-345), 95 parts by weight of toluene and ethyl acetate as a 1:1 mixed solvent, 0.05 parts by weight A platinum catalyst (manufactured by Dow Corning Toray Co., Ltd., trade name: SRX-212) was mixed, stirred and mixed to prepare a paint for forming the release agent layer of Comparative Example 1. On the surface of a polyethylene terephthalate film with a thickness of 38 μm, the paint used to form the release agent layer of Comparative Example 1 was coated with a thickness of 0.2 μm after drying using a Meyer rod. The hot air circulation oven at 120° C. was dried for 1 minute to obtain a peeling film of Comparative Example 1. On the other hand, with respect to 100 parts by weight of the adhesive polymer solution of Example 1 (a 30% ethyl acetate solution with a solid content), 0.3 parts by weight of N-butyl-4-methylpyridine were stirred and mixed. Fluorophosphate, 1.5 parts by weight of isocyanate curing agent (manufactured by Dow Corning Toray Co., Ltd., trade name: Corona (registered trademark) HX), and the adhesive composition of Comparative Example 1 was prepared.

After coating the adhesive composition of Comparative Example 1 on the surface of a polyethylene terephthalate film with a thickness of 38 μm so that the thickness after drying is 20 μm, it was performed using a hot air circulation drying oven at 100°C. Dry for 2 minutes to form an adhesive layer. Then, on the surface of the adhesive layer, the release agent layer (silicone-treated surface) of the release film of Comparative Example 1 prepared above was bonded. The obtained adhesive film was kept at a temperature of 40° C. for 5 days to cure the adhesive layer to obtain a surface protective film of Comparative Example 1.

(Comparative example 2)

Except that N-butyl-4-methylpyridine hexafluorophosphate was not added to the adhesive layer, in the same manner as in Comparative Example 1, a surface protective film of Comparative Example 2 was obtained.

(Comparative example 3)

Except that tetraethylene glycol di-2-ethylhexanoate as an ester plasticizer was not added to the release agent layer, the surface protection film of Comparative Example 3 was obtained in the same manner as in Example 1.

(Example 3)

The surface protective film of Example 3 was obtained in the same manner as in Example 1, except that the adhesive composition of Example 1 was replaced with the following adhesive composition. In the adhesive composition, relative to 100 parts by weight of A 30% ethyl acetate solution of adhesive polymer composed of 58 parts by weight of 2-ethylhexyl acrylate, 38 parts by weight of butyl acrylate, and 4 parts by weight of a copolymer of 2-hydroxyethyl acrylate, added In addition, 1.2 parts by weight of an isocyanate curing agent (manufactured by TOSOH CORPORATION, trade name: Corona (registered trademark) HX) was mixed.

(Example 4)

The surface protective film of Example 4 was obtained in the same manner as in Example 1, except that the adhesive composition of Example 1 was replaced with the following adhesive composition. In the adhesive composition, relative to 100 parts by weight A 30% ethyl acetate solution of adhesive polymer composed of 96 parts by weight of 2-ethylhexyl acrylate and 4 parts by weight of a copolymer of 2-hydroxyethyl acrylate, with 1.2 parts by weight of isocyanate added and mixed Curing agent (manufactured by TOSOH CORPORATION, trade name: Corona (Registered trademark) HX).

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

<Measurement method of peeling force of peeling film>

The sample of the surface protection film was cut to a width of 50 mm and a length of 150 mm. Under the test environment of 23℃×50%RH, the tensile testing machine was used to measure the strength when peeling the peeling film along the direction of 180° at a peeling speed of 300mm/min. 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 treatment polarizer (AG-LR polarizer) was bonded to the surface of the glass plate using a double-sided adhesive tape for a laminator. Then, a surface protective film cut into a width of 25 mm was bonded to the surface of the polarizer, and then stored in a test environment of 23° C.×50% RH for one day. After that, the tensile tester was used to measure the strength when peeling off the surface protection film along a 180° direction at a peeling speed of 300 mm/min, and this was used as the adhesive force (N/25mm).

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

The anti-glare and low-reflection treatment polarizer (AG-LR polarizer) was bonded to the surface of the glass plate using a double-sided adhesive tape for a laminator. Then, a surface protective film cut into a width of 25 mm was bonded to the surface of the polarizer, and then stored in a test environment of 23° C.×50% RH for one day. After that, a high-speed peel tester (manufactured by TESTER SANGYO CO,. LTD.) was used to peel off the surface protective film at a peeling speed of 40m per minute, while a surface potentiometer (manufactured by KEYENCE CORPORATION) was used to measure the surface potential of the polarizer surface every 10 ms, The maximum value of the absolute value of the surface potential at this time was taken as the peeling static voltage (kV).

<Determination method of surface fouling of surface protective film>

The anti-glare and low-reflection treatment polarizer (AG-LR polarizer) was bonded to the surface of the glass plate using a double-sided adhesive tape for a laminator. Then, a surface protective film cut to a width of 25 mm was bonded on the surface of the polarizer, and then stored in a test environment of 23° C.×50% RH for 3 days and 30 days. After that, the surface protection film was peeled off, and whether there was contamination on the surface of the polarizer was visually observed. As a criterion for the surface contamination, the case where there is no contamination transfer on the polarizing plate was evaluated as (○), and the case where contamination transfer on the polarizing plate was confirmed was evaluated as (×).

The measurement results of the obtained surface protective films of Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Tables 1 and 2. "2EHA" is 2-ethylhexyl acrylate, "HEA" is 2-hydroxyethyl acrylate, "BA" is butyl acrylate, "# 400G" is methoxy polyethylene glycol (400) methacrylate , "AS-a" is N-butyl-4-methylpyridine hexafluorophosphate, "AS-b" is 1-methyl-3-ethylimidazole hexafluorophosphate, "plasticizer" is four Ethylene glycol di-2-ethylhexanoate. In Tables 1 and 2, the composition of the adhesive layer is expressed in parts by weight so that the total amount of the adhesive polymer (solid content) is about 100 parts by weight. Therefore, in the adhesive layer of Comparative Example 1, the weight ratio of the adhesive polymer (solid content) to N-butyl-4-methylpyridine hexafluorophosphate is 30 parts by weight: 0.3 parts by weight = 100 parts by weight : 1.0 part by weight.

From the measurement results shown in Table 1 and Table 2, the following conclusions can be obtained.

The surface protection films of Examples 1 to 4 of the present invention have moderate adhesion, do not pollute the surface of the adherend, and have a low peeling static voltage when the surface protection film is peeled from the adherend.

On the other hand, the surface of Comparative Example 1 containing an antistatic agent in the adhesive layer The protective film, when peeling the surface protective film from the adherend, has a low and good peeling static voltage, but after peeling off, the contamination of the adherend increases.

In addition, the surface protective film of Comparative Example 2 in which both the adhesive layer of the surface protective film and the release agent layer of the release film did not contain an antistatic agent had good contamination to the adherend, but protected the surface When the film is peeled from the adherend, the peeling static voltage increases.

That is, the surface protective film of Comparative Example 1 in which the adhesive layer of the surface protective film contains an antistatic agent, and the comparative example in which neither the adhesive layer of the surface protective film nor the release agent layer of the release film contains an antistatic agent In the surface protection film of 2, it is difficult to balance the reduction of the peeling static voltage and the contamination of the adherend.

On the other hand, after the release agent layer of the release film contains the antistatic agent and the ester plasticizer, the antistatic agent and the ester plasticizer of the release agent layer are transferred only on the surface of the adhesive layer. In the surface protection films of Examples 1 to 4, the addition of a small amount of ester plasticizer has a significant effect of reducing the peeling static voltage. Therefore, there is no pollution to the adherend, and the peeling static resistance is also good.

In addition, in the surface protective film of Comparative Example 3 that contained only the antistatic agent in the release agent layer and did not contain the ester plasticizer, there was no contamination to the adherend, and the anti-peeling static electricity performance was also good. However, when compared with the surface protection films of Examples 1 to 4 in which an antistatic agent and an ester plasticizer were contained in the release agent layer, the peeling static voltage increased.

【Industrial Utilization Possibility】

The surface protection film of the present invention can be used in, for example, optical films such as polarizers, retardation plates, lens films, and other various optical components in production processes, etc., to be bonded to the optical components to protect the surface. In addition, the surface protective film of the present invention can reduce the static voltage generated when peeling from the adherend. In addition, the anti-peeling static electricity performance changes with time and the pollution to the adherend is small, which can improve the yield of the production process, and has great industrial use value.

1‧‧‧Base film

2‧‧‧Adhesive layer

3‧‧‧Resin film

4‧‧‧Release agent layer

5‧‧‧Peeling film

7‧‧‧Antistatic agent and ester plasticizer

10‧‧‧Surface protective film

Claims (4)

A surface protection film formed by forming an adhesive layer on one surface of a substrate film composed of a resin having transparency, and bonding a release film with a release agent layer on the adhesive layer It is characterized in that the release film is formed by laminating the release agent layer on one side of a resin film, wherein the release agent layer contains a release agent mainly composed of polydimethylsiloxane and does not interact with The release agent reacts with an antistatic agent and an ester plasticizer containing at least one ether bond. The antistatic agent component is an ionic compound with a cation and an anion with a melting point of 30 to 80°C. The cation is One or more selected from the group consisting of pyridinium cation, imidazole cation, pyrimidine cation, pyrazole cation, pyrrolidinium cation, ammonium cation, phosphine cation and sulfonium cation, the antistatic agent component and the ester plasticizer are selected from The release agent layer of the release film is transferred 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 patent application is characterized in that the adhesive layer is formed by crosslinking an adhesive composition containing a (meth)acrylate copolymer and a crosslinking agent. The surface protection film described in item 1 or 2 of the scope of the patent application is characterized in that the peeling force when the peeling film is peeled from the adhesive layer is 0.2 N/50 mm or less. An optical component formed by laminating the surface protective film described in any one of items 1 to 3 in the scope of patent application.

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