JP2016183243A - Surface protective film and optical component having the same stuck thereto - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface protective film which prevents a foreign matter (balled glue of adhesive) caused by an adhesive layer from occurring when cut to a predetermined size, has excellent conformability (wettability) to an optical film having unevenness thereon, causes little contamination on an adherend, and has excellent peeling antistatic performance while avoiding degradation with time, and to provide an optical component having the same stuck thereto.SOLUTION: There is provided a surface protective film 10 which has an adhesive layer 2 formed of a silicone adhesive composition containing polyether modified silicone on at least one surface of a transparent base material film 1, and has a film 5 for sticking having an antistatic agent layer 4 stuck onto the adhesive layer through the antistatic agent layer, where the film for sticking has an antistatic agent layer 4 containing a binder resin and an antistatic agent that does not react with the binder resin laminated on one surface of a resin film 3, the a component of the antistatic agent layer is transferred onto the surface of the adhesive layer from the film for sticking, and a peeling electrification voltage when the adhesive layer is peeled from an adherend is reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surface protective film that is attached to the surface of an optical component such as a polarizing plate, a retardation plate, a lens film for display, or a cover glass. More specifically, foreign matter (adhesive glue balls) caused by the adhesive layer is less likely to occur even when trimmed to a predetermined size, and is compatible with optical films with uneven surfaces (wetability). Therefore, the present invention provides a surface protective film having excellent anti-peeling performance without deterioration over time, with little contamination to the adherend, and an optical component on which the surface protective film is bonded.

  When manufacturing and transporting optical films such as polarizing plates, retardation plates, lens films for displays, antireflection films, hard coat films, transparent conductive films for touch panels, and displays using the same. For example, a surface protective film is bonded to the surface of the optical film to prevent the surface from being stained or scratched in the subsequent step. The appearance inspection of the optical film, which is a product, may be performed while the surface protective film is bonded to the optical film in order to remove the trouble of bonding the surface protective film and increase the work efficiency again.

  Conventionally, a surface protective film provided with a pressure-sensitive adhesive layer on one surface of a base film is generally used in order to prevent adhesion of scratches and dirt in the manufacturing process of optical products. The surface protective film is bonded to the optical film via a pressure-sensitive adhesive layer. The adhesive layer has a slight adhesive force because it can be easily removed when the used surface protection film is removed from the surface of the optical film and the adhesive is an adherend. This is to prevent the adhesive film from adhering and remaining on the optical film (preventing the occurrence of so-called adhesive residue).

  In surface protection films for optical parts, acrylic adhesives are often used. However, when the optical film bonded with the surface protective film is cut to a predetermined size according to the dimensions of the display, the adhesive of the surface protective film is torn off by the cutting blade, and a small piece of foreign matter (glue ball) There is a problem that it is easy to occur. When such foreign matter is generated, it may cause problems such as process contamination (contamination of used devices, semi-finished products, etc.) and generation of traces on the optical film. For this reason, there is a demand for a surface protective film that generates less foreign matter when slitting or cutting an optical film having a surface protective film bonded thereto. Also, it has good conformability (wetting) to optical films with irregularities on the surface, such as prism sheets and antiglare-treated polarizing plates, and air bubbles enter when the surface protective film is bonded to the optical film. There is a need for difficult surface protection films.

  As described above, a polyurethane-based adhesive or a silicone-based adhesive is required because it is difficult to generate adhesive balls of adhesive during slitting and cutting, and a surface protective film having good compatibility with various optical films is required. A surface protective film using is preferably used.

In recent years, in the production process of a liquid crystal display panel, the surface protection film bonded on the optical film is controlled by a peeling voltage generated when the surface protective film is peeled off and removed. The phenomenon of circuit components such as driver ICs being destroyed and the phenomenon of damaging the orientation of liquid crystal molecules are occurring with a small number of occurrences.
Further, in order to reduce the power consumption of the liquid crystal display panel, the driving voltage of the liquid crystal material has been lowered, and accordingly, the breakdown voltage of the driver IC has also been lowered. Recently, it has been required to set the peeling band voltage within the range of +0.7 kV to -0.7 kV.

  When peeling the surface protection film from the optical film that is the adherend, use an adhesive layer containing an antistatic agent to keep the stripping voltage low to prevent problems due to high stripping voltage. Surface protection films that have been proposed have been proposed.

  Patent Document 1 and Patent Document 2 disclose a surface protective film using an acrylic pressure-sensitive adhesive containing an acrylic polymer and an antistatic agent. Patent Document 3 discloses an antistatic pressure-sensitive adhesive comprising a polyurethane having an alkylene oxide chain, an ionic compound, and a trifunctional isocyanate compound. Patent Document 4 discloses a polyurethane pressure-sensitive adhesive composition for a surface protective film, which contains at least one salt of an alkali metal salt of an ultrastrong acid or an alkaline earth metal salt. Furthermore, Patent Document 5 discloses an adhesive composition comprising an ionic liquid containing a fluoroorganic anion, a polyurethane having a number average molecular weight of 5,000 or more, and a surface protective film using the adhesive composition. Yes. Patent Document 6 discloses a conductive silicone pressure-sensitive adhesive composition comprising a silicone-based pressure-sensitive adhesive and conductive powder.

JP 2005-131957 A Japanese Patent Laying-Open No. 2005-330464 JP 2005-154491 A JP 2006-182794 A JP 2007-277484 A Japanese Patent No. 3956121

  In the surface protective films described in Patent Documents 1 and 2, since an acrylic adhesive is used, when the optical film is cut into a predetermined size according to the size of the display, the adhesive is a cutting blade. There is a problem in that small pieces of foreign matter (also called paste balls) are easily generated. When such a foreign substance is generated, it may cause problems such as process contamination and generation of traces on the optical film.

  In the surface protective films described in Patent Documents 3 to 5, since a urethane-based adhesive is used, the generation of small pieces (glue balls) during cutting of an optical film is small, but a silicone-based adhesive. Compared to the above, there is a problem that the conformability (wetting property) to the adherend is inferior. Although it does not become a big problem with respect to the optical film and glass with a comparatively smooth surface, there existed a problem that adaptability was inferior with respect to the optical film which has uneven | corrugated shape on the surface.

  On the other hand, in the conductive silicone pressure-sensitive adhesive composition for adhesion described in the above-mentioned Patent Document 6, since conductive powder is used for the silicone pressure-sensitive adhesive, there is a problem that optical properties such as transparency are inferior. However, it has been difficult to use as a surface protective film to be adhered to the surface of optical parts such as glass and various optical films.

  The present invention has been made in view of the above circumstances, and it is difficult for foreign matters (adhesive balls of adhesive) to be generated due to the adhesive layer when cutting to a predetermined size, and the surface has irregularities. Surface protective film that has excellent conformability (wetability) to the film, little contamination to the adherend, and excellent anti-peeling antistatic performance without deterioration over time, and optical component on which it is bonded It is an issue to provide.

The present inventors have intensively studied this problem.
In order to obtain a surface protection film that does not easily generate foreign matter (glue balls) due to the pressure-sensitive adhesive layer during cutting and has good conformability (wetting properties) to optical films with uneven surfaces, It was judged that an adhesive was suitable. In view of this, a pressure-sensitive adhesive layer that can impart antistatic properties to the silicone pressure-sensitive adhesive layer and does not deteriorate the optical characteristics was investigated. In addition, in order to reduce the contamination of the adherend and reduce the change in contamination over time, it was considered necessary to reduce the content of the antistatic agent presumed to contaminate the adherend. . Furthermore, a method for suppressing the stripping voltage when the surface protective film was peeled from the adherend without increasing the content of the antistatic agent was studied.

  The present invention does not form an adhesive layer by mixing an antistatic agent in an adhesive composition, but first, an adhesive composition containing no antistatic agent is applied to one side of a substrate. Work and dry to stack the adhesive layer. After that, a film for laminating having a resin layer containing an antistatic agent is laminated so that the pressure-sensitive adhesive layer and the antistatic agent layer are in contact with each other, and an appropriate amount of an antistatic agent component is applied to the surface of the pressure-sensitive adhesive layer. The technical idea is to transfer and apply from the side of the laminating film. The present inventors have found that a surface protective film capable of suppressing the peeling voltage when the surface protective film is peeled from the adherend can be obtained by this technical idea, and completed the present invention.

  That is, in order to solve the above problems, the present invention has a pressure-sensitive adhesive layer made of a silicone pressure-sensitive adhesive composition containing polyether-modified silicone on at least one surface of a transparent substrate, and the pressure-sensitive adhesive layer is formed on the pressure-sensitive adhesive layer. In the surface protective film in which the laminating film having the antistatic agent layer is laminated via the antistatic agent layer, the laminating film is provided on one side of the resin film as the antistatic agent layer. An antistatic agent layer containing a binder resin and an antistatic agent that does not react with the binder resin is laminated, and the components of the antistatic agent layer are transferred from the laminating film to the surface of the adhesive layer. And providing a surface protective film characterized in that a peeling voltage when the pressure-sensitive adhesive layer is peeled off from the adherend is reduced.

  The antistatic agent is preferably an ionic compound.

  The antistatic agent is preferably an ionic compound having an alkali metal as a cation.

  Moreover, it is preferable that the thickness of the said adhesive layer is 2-250 micrometers.

  Moreover, it is preferable that the peeling force at the time of peeling the said film for bonding from the said adhesive layer is 0.005-0.3N / 50mm.

  Moreover, this invention provides the optical component formed by bonding said surface protection film.

The surface protective film of the present invention is less likely to generate foreign matter (glue balls) due to the pressure-sensitive adhesive layer at the time of cutting, has good conformability (wetability) to an optical film having irregularities on the surface, and It is possible to provide a surface protective film having excellent anti-peeling performance without deteriorating with time with little contamination to the adherend, and an optical component on which the surface protective film is bonded.
Further, according to the surface protective film of the present invention, it is possible to suppress the generation of foreign matters (glue balls) due to the pressure-sensitive adhesive layer even at the time of cutting, so that process contamination or traces are generated on the optical film. The occurrence of defects can be prevented.
Moreover, according to the surface protective film of this invention, since the surface of an optical film can be protected reliably, the improvement of productivity and the improvement of a yield can be aimed at.

It is a conceptual sectional view of the surface protection film of the present invention. It is sectional drawing which shows the state which peeled off the film for bonding from the surface protection film of this invention. It is sectional drawing which shows one of the Examples which bonded the surface protection film of this invention to the optical component.

Hereinafter, the present invention will be described in detail based on embodiments.
FIG. 1 is a conceptual cross-sectional view of the surface protective film of the present invention. The surface protective film 10 has a pressure-sensitive adhesive layer 2 formed on the surface of one side of a transparent base film 1. On the surface of the pressure-sensitive adhesive layer 2, a bonding film 5 in which an antistatic agent layer 4 is formed on the surface of a resin film 3 is bonded.

  As the substrate film 1 used for the surface protective film 10 according to the present invention, a substrate film (transparent substrate) made of a resin having transparency and flexibility is used. Thereby, the external appearance test | inspection of an optical component can be performed in the state which bonded the surface protection film to the optical component which is a to-be-adhered body. The film made of a resin having transparency used as the base film 1 is preferably a polyester film such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, or polybutylene terephthalate. In addition to the polyester film, a film made of another resin can be used as long as it has a required strength and optical suitability. The base film 1 may be an unstretched film or a uniaxially or biaxially stretched film. Moreover, you may control the draw ratio of a stretched film, and the orientation angle of the axial direction formed with crystallization of a stretched film to a specific value.

Although the thickness of the base film 1 used for the surface protection film 10 according to the present invention is not particularly limited, for example, a thickness of about 12 to 100 μm is preferable, and a thickness of about 20 to 50 μm is easy to handle. preferable.
Further, if necessary, an antifouling layer for preventing the surface from being stained, an antistatic agent layer, a hard coat layer for preventing scratches, etc. on the surface opposite to the surface on which the adhesive layer 2 of the base film 1 is formed. Can be provided. Further, the surface of the base film 1 may be subjected to easy adhesion treatment such as surface modification by corona discharge and application of an anchor coating agent.

  The pressure-sensitive adhesive layer 2 used in the surface protective film 10 according to the present invention is a pressure-sensitive adhesive that adheres to the surface of an adherend and can be easily peeled off after use and hardly contaminates the adherend. . In addition, a silicone-based pressure-sensitive adhesive is suitable because it produces less glue balls during cutting and has good wettability to an adherend such as an optical film.

As the silicone-based pressure-sensitive adhesive, there are an addition reaction type and a peroxide curing type depending on the reaction form, but the addition reaction type is preferable because the adherend contamination property is low. Moreover, the adhesive force of an adhesive can be changed with the compounding ratio of a linear silicone polymer and a silicone resin, and the crosslinking density of a silicone polymer. The pressure-sensitive adhesive used for the surface protective film is preferably one having a relatively light adhesive strength.
Examples of commercially available silicone adhesives include Shin-Etsu Chemical KR-3704, X40-3306, Toray Dow Corning DC7651ADHESIVE, SD7587L PSA, Aika Kogyo SE9500, SE9600, and the like.

  The silicone pressure-sensitive adhesive preferably contains a polyether-modified silicone in order to facilitate the transfer of the antistatic agent from the laminating film. The polyether-modified silicone is added to increase the affinity between the silicone pressure-sensitive adhesive and the antistatic agent and to easily impart antistatic performance to the pressure-sensitive adhesive layer. The polyether-modified silicone may be a polysiloxane having a polyalkylene oxide group (polymethyl polyalkylene oxide siloxane), and may be a copolymer of polydimethylsiloxane and polymethyl polyalkylene oxide siloxane as necessary. Examples of the polyalkylene oxide include ethylene oxide, propylene oxide, and a copolymer of ethylene oxide and propylene oxide. There are various types of polyether-modified silicones depending on the presence or absence of polydimethylsiloxane components, copolymerization ratios, types of polyalkylene oxide groups, etc., and can be selected in consideration of antistatic performance and adherend contamination. Good.

  As commercially available polyether-modified silicones, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF manufactured by Shin-Etsu Chemical Co., Ltd. -643, KF-644, KF-6020, KF-6204, KF-6011, KF-6012, KF-6015, KF-6017, Toray Dow Corning SH8700, SH8400, SF8410, L-7002, FZ-2104, FZ-77, L-7606, etc. are mentioned.

  The thickness of the pressure-sensitive adhesive layer 2 used in the surface protective film 10 according to the present invention may be selected according to the type and surface shape of the adherend, but is often about 2 to 250 μm. A thickness of about 5 to 40 μm is preferable and a thickness of about 10 to 30 μm is more preferable from the viewpoint of price and conformability to the adherend. It is the surface protection from the adherend that the peel strength (adhesive strength) of the surface protective film to the surface of the adherend is about 0.03 to 0.3 N / 25 mm and has a slight adhesive strength. It is preferable because it is excellent in operability when peeling the film. Moreover, since it is excellent in the operativity at the time of peeling the film 5 for bonding from the surface protection film 10, the peeling force when peeling the film 5 for bonding from the adhesive layer 2 is peeling rate 0.3m / min. When measured under the condition of a peeling angle of 180 °, it is preferably 0.005 to 0.3 N / 50 mm.

  Moreover, the film 5 for bonding used for the surface protection film 10 according to the present invention includes an antistatic agent layer 4 containing a binder resin and an antistatic agent that does not react with the binder resin on one surface of the resin film 3. Are stacked.

Examples of the resin film 3 include a polyester film, a polyamide film, a polyethylene film, a polypropylene film, and a polyimide film. The polyester film is particularly preferable because of its excellent transparency and a relatively low price. preferable. The resin film may be an unstretched film or a uniaxially or biaxially stretched film. Moreover, you may control the draw ratio of a stretched film, and the orientation angle of the axial direction formed with crystallization of a stretched film to a specific value.
Although the thickness of the resin film 3 is not particularly limited, for example, a thickness of about 12 to 100 μm is preferable, and a thickness of about 20 to 50 μm is more preferable because it is easy to handle.
Further, if necessary, the surface of the resin film 3 may be subjected to easy adhesion treatment such as surface modification by plasma discharge or corona discharge, application of an anchor coating agent, and the like.

  Examples of the binder resin constituting the antistatic agent layer 4 include polyester resin, polyurethane resin, polyamide resin, polyimide resin, polyolefin resin, alkyd resin, cellulose resin, polyvinyl alcohol resin, melamine resin, and phenol resin. As the binder resin, any of a crosslinking type, a type that volatilizes a solvent or a dispersion medium, and the like can be used.

  The antistatic agent 7 constituting the antistatic agent layer 4 has good dispersibility with respect to the binder resin solution and does not inhibit the curing of the binder resin if the binder resin is of a curing type. Is preferred. Moreover, since it transfers to the surface of the adhesive layer 2 from the antistatic agent layer 4 and provides the antistatic effect to the adhesive layer 2, the antistatic agent which does not react with binder resin is good. As such an antistatic agent, an ionic compound is suitable.

The ionic compound is an ionic compound having a cation and an anion, and the cation includes an alkali metal cation, a pyridinium cation, an imidazolium cation, a pyrimidinium cation, a pyrazolium cation, a pyrrolidinium cation, and an ammonium cation. And organic cation or inorganic cation such as phosphonium cation and sulfonium cation. The anions 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 ^- such as, include organic or inorganic anion. These ionic compounds may be used alone or in admixture of two or more. In order to stabilize the ionic substance, a compound containing a polyoxyalkylene structure may be added.

Among these, an ionic compound (alkali metal salt) having an alkali metal cation as a cation is preferable. Examples of the alkali metal salt include metal salts composed of lithium, sodium, and potassium. Specifically, for example, a cation selected from Li ⁺ , Na ⁺ , K ^{+ and the} like, 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 a anion selected from such Constructed metal salts are preferably used. Among these, 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 ) Lithium salts such as ₂ N and Li (CF ₃ SO ₂ ) ₃ C are preferably used. As these alkali metal salts, one kind of alkali metal salt may be used alone, or two or more kinds may be mixed and used. In order to stabilize the ionic substance, a compound containing a polyoxyalkylene structure may be added.

  The amount of antistatic agent added to the binder resin varies depending on the type of antistatic agent and the degree of affinity with the binder resin, but the desired stripping voltage and deposition when peeling the surface protective film from the adherend. What is necessary is just to set in consideration of the contamination property to the body and the adhesive property.

  There is no particular limitation on the method of mixing the binder resin and the antistatic agent. A method of adding and mixing an antistatic agent after diluting a binder resin with a solvent or a dispersion medium, a method of diluting a binder resin and an antistatic agent after mixing the binder resin and the antistatic agent, After diluting with a dispersion medium, any method such as mixing both may be used. In addition, if necessary, a crosslinking agent or crosslinking catalyst for curing the binder resin, an adhesion improver for improving the adhesion of the binder resin to the resin film, or a binder resin coating containing an antistatic agent is applied. Additives such as leveling agents for improving workability may be added.

  The mixing ratio of the binder resin and the antistatic agent is not particularly limited, but a ratio of about 5 to 100 with the antistatic agent as the solid content is preferable with respect to the solid content 100 of the binder resin. When the addition amount of the antistatic agent in terms of solid content is less than 5 with respect to the solid content 100 of the binder resin, the transfer amount of the antistatic agent 7 to the surface of the adhesive layer 2 also decreases, and the adhesive layer 2 makes it difficult to exhibit antistatic properties against peeling. Further, when the addition amount of the antistatic agent in terms of solid content exceeds 100 ratio with respect to the solid content 100 of the binder resin, the binder resin as well as the antistatic agent 7 is transferred to the surface of the pressure-sensitive adhesive layer 2. Therefore, there is a possibility that the adhesive property of the adhesive layer 2 is lowered.

  The method for forming the pressure-sensitive adhesive layer 2 and the method for laminating the laminating film 5 on the base film 1 of the surface protective film 10 according to the present invention may be carried out by known methods, and are not particularly limited. Specifically, a method of laminating the laminating film 5 after applying a resin composition for forming the pressure-sensitive adhesive layer 2 on one side of the base film 1 and drying to form a pressure-sensitive adhesive layer is generally used. Is.

  Moreover, what is necessary is just to perform the adhesive layer 2 on the surface of the base film 1 by a well-known method. Specifically, known coating methods such as reverse coating, comma coating, gravure coating, slot die coating, Mayer bar coating, and air knife coating can be used.

  Similarly, the antistatic agent layer 4 may be formed on the resin film 3 by a known method. Specifically, known coating methods such as gravure coating, Mayer bar coating, and air knife coating can be used.

  The surface protective film 10 according to the present invention having the above configuration preferably has a surface potential of +0.7 kV to −0.7 kV when peeled from the optical film as an adherend. Furthermore, the surface potential is more preferably +0.5 kV to −0.5 kV, and the surface potential is particularly preferably +0.1 kV to −0.1 kV. This surface potential can be adjusted by adjusting the type and amount of the antistatic agent 7 contained in the antistatic agent layer 4.

FIG. 2 is a cross-sectional view showing a state in which the laminating film is peeled off from the surface protective film of the present invention.
By peeling off the laminating film 5 from the surface protective film 10 shown in FIG. 1, a part of the antistatic agent (symbol 7) contained in the antistatic agent layer 4 of the laminating film 5 becomes a surface protective film. It is transferred (attached) to the surface of the ten pressure-sensitive adhesive layers 2. Therefore, in FIG. 2, the antistatic agent adhering to the surface of the pressure-sensitive adhesive layer 2 of the surface protective film is schematically indicated by the reference numeral 7. When the component of the antistatic agent 7 is transferred from the bonding film 5 to the surface of the pressure-sensitive adhesive layer 2, the pressure-sensitive adhesive layer 2 is peeled off from the adherend as compared with the pressure-sensitive adhesive layer 2 before transfer. The peeling voltage at the time is reduced. In addition, the peeling voltage at the time of peeling an adhesive layer from a to-be-adhered body can be measured by a well-known method. For example, after the surface protective film is bonded to an adherend such as a polarizing plate, the surface of the adherend is peeled off at a peeling speed of 40 m / min using a high speed peel tester (manufactured by Tester Sangyo). The maximum value of the absolute value of the surface potential when the surface potential is measured every 10 ms by using a surface potentiometer (manufactured by Keyence Corporation) is measured as a peeling voltage (kV).
In the surface protective film according to the present invention, when the surface protective film 11 in the state where the film for bonding shown in FIG. 2 is peeled off is bonded to the adherend, the charge transferred to the surface of the pressure-sensitive adhesive layer 2 is transferred. The inhibitor contacts the surface of the adherend. As a result, the stripping voltage when the surface protective film is peeled off from the adherend can be kept low.

FIG. 3 is a cross-sectional view showing an example in which the surface protective film of the present invention is bonded to an optical component.
From the surface protective film 10 of the present invention, the adhesive film 2 is peeled off and the pressure-sensitive adhesive layer 2 is exposed (surface protective film 11 in FIG. 2), and the adherend is interposed through the pressure-sensitive adhesive layer 2. It is bonded to the optical component 8.
That is, FIG. 3 has shown the optical component 20 with which the surface protection film 11 of the state which peeled the film 5 for bonding from the surface protection film 10 of this invention was bonded. Examples of the optical component 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. Such an optical component is used as a constituent member of a liquid crystal display device such as a liquid crystal display panel, an optical system device of various instruments, and the like. Examples of the optical component include optical films such as an antireflection film, a hard coat film, and a transparent conductive film for a touch panel.
When the surface protective film 11 in a state where the bonding film 5 is peeled off from the surface protective film 10 of the present invention is peeled off from the optical component (optical film) as an adherend, the peeling voltage is sufficiently low. Can be suppressed. Therefore, there is no fear of destroying circuit components such as a driver IC, a TFT element, and a gate line driving circuit, and the production efficiency in the process of manufacturing a liquid crystal display panel and the like can be improved and the reliability of the production process can be maintained.

Next, the present invention will be further described with reference to examples.
Example 1
(Production of surface protective film)
1.5 parts by weight of ethyl cellulose (Etcel (registered trademark) 100FP manufactured by Dow Chemical), 1.125 parts by weight of a 20% ethyl acetate solution of lithium bis (fluorosulfonyl) imide, a 1: 1 mixed solvent of toluene and ethyl acetate 98. 5 parts by weight were mixed and stirred and mixed to prepare a coating material for forming the antistatic agent layer of Example 1. The paint for forming the antistatic agent layer of Example 1 was applied to the surface of a polyethylene terephthalate film having a thickness of 38 μm with a Mayer bar so that the thickness after drying was 0.2 μm, and a hot air circulation type at 120 ° C. It dried for 1 minute in oven, and the film for bonding of Example 1 was obtained. Meanwhile, 100 parts by weight of a silicone pressure-sensitive adhesive (manufactured by Shin-Etsu Chemical Co., Ltd., product name: X-40-3306), 0.2 part by weight of a catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., product name: PL-50T), polyether The coating liquid obtained by adding and mixing 1.0 part by weight of modified silicone oil (manufactured by Toray Dow Corning Co., Ltd., product name: SH8400) was dried on the surface of a polyethylene terephthalate film having a thickness of 38 μm, and the thickness after drying was 20 μm. Thus, after apply | coating, it was made to dry for 2 minutes in 100 degreeC hot-air circulation type oven, and the adhesive layer was formed. Then, the antistatic agent layer (antistatic treatment surface) of the film for pasting of Example 1 produced above was bonded to the surface of this adhesive layer. The obtained pressure-sensitive adhesive film was kept warm at 40 ° C. for 5 days to cure the pressure-sensitive adhesive, and the surface protective film of Example 1 was obtained.

(Example 2)
A surface protective film of Example 2 was obtained in the same manner as in Example 1 except that the antistatic agent was changed to lithium bis (trifluoromethanesulfonyl) imide.

Example 3
The coating material for forming the antistatic agent layer of Example 1 was prepared by using 3.125 parts by weight of aminoalkyd resin (manufactured by Hitachi Chemical Co., Ltd., product name: Tessfine (registered trademark) 303), catalyst (Hitachi Chemical Industry Co., Ltd.). Manufactured, product name: dryer 900) 0.1 parts by weight, lithium bis (trifluoromethanesulfonyl) imide 20% ethyl acetate solution 1 part, toluene and ethyl acetate 1: 1 mixed solvent 96.275 parts by weight A surface protective film of Example 3 was obtained in the same manner as in Example 1 except that the paint was stirred and mixed.

(Comparative Example 1)
A mixture of 1.5 parts by weight of ethyl cellulose (Etocel (registered trademark) 100FP manufactured by Dow Chemical) and 98.5 parts by weight of a 1: 1 mixed solvent of toluene and ethyl acetate was stirred and mixed. The paint on the film side was adjusted. On the surface of a polyethylene terephthalate film having a thickness of 38 μm, the paint on the side of the laminating film of Comparative Example 1 was applied with a Mayer bar so that the thickness after drying was 0.2 μm, and a 120 ° C. hot-air circulating oven And dried for 1 minute to obtain a laminating film of Comparative Example 1. Meanwhile, 100 parts by weight of a silicone pressure-sensitive adhesive (manufactured by Shin-Etsu Chemical Co., Ltd., product name: X-40-3306), 0.2 part by weight of a catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., product name: PL-50T), polyether Modified silicone oil (Toray Dow Corning Co., Ltd., product name: SH8400) 1.0 part by weight, lithium bis (fluorosulfonyl) imide 20% ethyl acetate solution 2.5 parts by weight was added and mixed. The film was applied to the surface of a polyethylene terephthalate film having a thickness of 38 μm so that the thickness after drying was 20 μm, and then dried in a hot air circulation oven at 100 ° C. for 2 minutes to form an adhesive layer. Then, the binder resin coating layer of the film for pasting of the comparative example 1 produced above was bonded on the surface of this adhesive layer. The obtained pressure-sensitive adhesive film was kept warm at 40 ° C. for 5 days to cure the pressure-sensitive adhesive, and the surface protective film of Comparative Example 1 was obtained.

(Comparative Example 2)
A surface protective film of Comparative Example 2 was obtained in the same manner as in Example 1 except that lithium bis (fluorosulfonyl) imide was not added to the antistatic agent layer. In this case, a binder resin coating layer that does not contain an antistatic agent is formed on the surface of the laminating film, as in Comparative Example 1.

(Comparative Example 3)
A surface protective film of Comparative Example 3 was obtained in the same manner as in Example 1, except that 1.0 part by weight of SH8400 was added to the antistatic agent layer without adding SH8400 to the adhesive layer.

The evaluation test methods and results are shown below.
(Surface resistivity of antistatic agent layer and adhesive layer)
The surface resistivity of the antistatic agent layer of the laminating film and the surface resistivity of the pressure-sensitive adhesive layer of the surface protective film are measured with a high performance high resistivity meter (Hiresta (registered trademark) -UP manufactured by Mitsubishi Chemical Analytech Co., Ltd.). The measurement was performed under the conditions of an applied voltage of 100 V and a measurement time of 30 seconds. The measurement is carried out by keeping the pressure-sensitive adhesive film bonded with the pressure-sensitive adhesive layer and the antistatic agent layer in an environment of 40 ° C. for 5 days, then peeling the film for bonding from the pressure-sensitive adhesive film, and bonding it to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film. The surface resistivity (Ω / □) of the antistatic agent layer of the film is measured.

(Measurement method of peel strength of laminating film)
A sample of the surface protective film is cut into a width of 50 mm and a length of 150 mm. In a test environment of 23 ° C. × 50% RH, the strength when the laminated film was peeled in the direction of 180 ° at a peeling speed of 300 mm / min was measured using a tensile tester, and this was measured. The peeling force (N / 50 mm) was used.

(Measurement method of adhesive strength of surface protective film)
A polarizing plate (AG-LR polarizing plate) subjected to antiglare low reflection treatment was bonded to the surface of the glass plate using a bonding machine. Thereafter, a surface protective film cut to a width of 25 mm was bonded to the surface of the polarizing plate, and then stored for 1 day in a test environment of 23 ° C. × 50% RH. Then, the strength when the surface protective film was peeled in the direction of 180 ° at a peeling speed of 300 mm / min was measured using a tensile tester, and this was defined as adhesive strength (N / 25 mm).

(Measurement method of peeling voltage of surface protective film)
A polarizing plate (AG-LR polarizing plate) subjected to antiglare low reflection treatment was bonded to the surface of the glass plate using a bonding machine. Thereafter, a surface protective film cut to a width of 25 mm was bonded to the surface of the polarizing plate, and then stored for 1 day in a test environment of 23 ° C. × 50% RH. Then, using a surface potentiometer (manufactured by Keyence Corporation), the surface potential of the polarizing plate surface was peeled off while peeling the surface protective film at a peeling speed of 40 m / min using a high-speed peel tester (manufactured by Tester Sangyo). The maximum value of the absolute value of the surface potential when measured every 10 ms was defined as the stripping voltage (kV).

(Method for confirming surface contamination of surface protective film)
A polarizing plate (AG-LR polarizing plate) subjected to antiglare low reflection treatment was bonded to the surface of the glass plate using a bonding machine. Thereafter, a surface protective film cut to a width of 25 mm was bonded to the surface of the polarizing plate, and then stored for 3 days and 30 days in a test environment of 23 ° C. × 50% RH. Thereafter, the surface protective film was peeled off, and the presence or absence of contamination on the surface of the polarizing plate was visually observed to confirm surface contamination. As criteria for determining surface contamination, the case where there was no migration of contamination on the polarizing plate was marked with (◯), and the case where the migration of contamination was confirmed on the polarizing plate was marked with (×).

Table 1 shows the measured results of the obtained surface protective films of Examples 1 to 3 and Comparative Examples 1 to 3. “X40-3306” is X-40-3306, “PL-50T” is PL-50T, “SH8400” is SH8400, “100FP” is Etocel® 100FP, “LiFSI” is Lithium bis (fluorosulfonyl) imide, “LiTFSI” means lithium bis (trifluoromethylsulfonyl) imide, “T303” means Tesfine (registered trademark) 303, and “D900” means dryer 900.
The “bonding layer” is a general term for an antistatic agent layer and a binder resin coating layer that are laminated on one side of a bonding film.
The surface resistivity A is a value obtained by measuring the surface resistivity (Ω / □) of the pressure-sensitive adhesive layer of the surface protective film of the present invention. Further, the surface resistivity B is a value obtained by measuring the surface resistivity (Ω / □) of the antistatic agent layer of the laminating film after peeling from the surface of the pressure-sensitive adhesive layer. OR in Table 1 is an abbreviation for overrange, meaning that the measurement range of the high performance high resistivity meter (Hiresta (registered trademark) -UP manufactured by Mitsubishi Chemical Analytech Co., Ltd.) is exceeded, and the surface resistivity is 1E + 13Ω. / □ means more than. In the notation of surface resistivity, for example, 1.7E + 10 means 1.7 × 10 to the 10th power. The unit of surface resistivity is Ω / □.

From the measurement results shown in Table 1, the following can be understood.
The surface protective films of Examples 1 to 3 according to the present invention have an appropriate adhesive force, have no contamination on the surface of the adherend, and have a peeling voltage when the surface protective film is peeled from the adherend. Low.
On the other hand, the surface protective film of Comparative Example 1 in which the antistatic agent is mixed with the pressure-sensitive adhesive layer has a low and low peel voltage when the surface protective film is peeled off from the adherend. The contamination to the kimono increased. Further, in the surface protective film of Comparative Example 2 in which no antistatic agent was used, the contamination with respect to the adherend was improved, but the peel voltage when the surface protective film was peeled off from the adherend was increased. The surface protection film of Comparative Example 3 used on the bonding layer side without using the polyether-modified silicone on the pressure-sensitive adhesive layer side also had a high peel voltage when the surface protection film was peeled off from the adherend.

  The surface protective film of the present invention is, for example, in production processes of optical films such as polarizing plates, retardation plates, lens films, antireflection films, hard coat films, transparent conductive films, and other various optical components. , And can be used to protect the surface by bonding to the optical component or the like. In addition, the surface protective film of the present invention is less likely to cause foreign matter (glue balls) due to the pressure-sensitive adhesive layer at the time of cutting, and has good conformability (wetting) to an optical film having irregularities on the surface, Since it has excellent anti-separation performance without deterioration over time, the amount of static electricity generated when it is peeled off from the adherend can be reduced, and there is little change in the anti-peeling performance over time and contamination of the adherend. The yield can be improved and the industrial utility value is great.

DESCRIPTION OF SYMBOLS 1 ... Base film, 2 ... Adhesive layer, 3 ... Resin film, 4 ... Antistatic agent layer, 5 ... Laminating film, 7 ... Antistatic agent, 8 ... Adhering body (optical component), 10 ... Surface Protective film, 11... Surface protective film from which film for bonding is peeled off, 20... Optical component bonded with surface protective film.

Claims (6)

  A film for laminating having an adhesive layer comprising a silicone adhesive composition containing polyether-modified silicone on at least one surface of a transparent substrate, and having an antistatic agent layer on the adhesive layer, In the surface protective film bonded through the antistatic agent layer, the film for laminating is formed on one side of the resin film as the antistatic agent layer, a binder resin, and an antistatic agent that does not react with the binder resin; When the antistatic agent layer containing is laminated, the components of the antistatic agent layer are transferred from the laminating film to the surface of the adhesive layer, and the adhesive layer is peeled off from the adherend A surface protective film having a reduced stripping voltage.   The surface protection film according to claim 1, wherein the antistatic agent is an ionic compound.   The surface protection film according to claim 1, wherein the antistatic agent is an ionic compound having an alkali metal as a cation.   The surface protective film according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 2 to 250 μm.   The surface protection film according to any one of claims 1 to 4, wherein a peeling force when the film for laminating is peeled from the pressure-sensitive adhesive layer is 0.005 to 0.3 N / 50 mm. .   An optical component obtained by bonding the surface protective film according to claim 1.

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