KR20180027481A - Antistatic surface-protective film and optical component attached with the same - Google Patents

Abstract

The present invention provides an antistatic surface protective film in which a foreign substance (adhesive paste) originating from an adhesive is difficult to appear even at the time of cutting; has great affinity (wettability) to an optical film having irregularities on a surface which is an adherend; has low contaminating property and the low contaminating property to the adherend does not change even with lapse of time; and has excellent peeling antistatic performance without deterioration due to aging, and an optical component to which the antistatic surface protective film is attached. A polyurethane-based adhesive layer (2) not containing an antistatic agent, an antistatic agent layer (3), and a peeling film (4) processed to be peeled are laminated in order on one surface of a base film (1) made of a resin having transparency to form the antistatic surface protective film (10).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an antistatic surface protective film and an optical component having the antistatic surface protective film,

The present invention relates to a surface protective film that is applied to the surface of an optical component such as a polarizing plate, a retarder, and a lens film for display (hereinafter, sometimes referred to as an optical film). More particularly, the present invention relates to a pressure-sensitive adhesive composition which is excellent in affinity (wettability) for an optical film having irregularities on the surface, and is free from contamination to an adherend An antistatic surface protective film which does not deteriorate over time and has excellent peeling electrification preventing performance, and an optical component to which the antistatic surface protective film is adhered.

When an optical product such as a polarizing plate, a retardation film, a lens film for display, an antireflection film, a hard coat film, a transparent conductive film for a touch panel, and a display using the optical film is manufactured and transported, To prevent contamination and scratches on the surface in a subsequent process. The appearance inspection of the optical film, which is a product, may be carried out in a state in which the surface protective film is stuck to the optical film in order to reduce the labor of peeling the surface protective film, and to improve the working efficiency.

Background Art [0002] Conventionally, a surface protective film having a pressure-sensitive adhesive layer formed on one surface of a base film is generally used to prevent scratches or contamination from adhering to the surface of a base film in the production process of optical products. The surface protective film is bonded to the optical film through a pressure-sensitive adhesive layer having no adhesive force. Adhesive strength of the pressure sensitive adhesive layer can be easily peeled off when the used surface protective film is peeled off from the surface of the optical film and the pressure sensitive adhesive is adhered to the optical film of the product to be adhered so as not to remain (To prevent the occurrence of so-called adhesive residue).

Although acrylic pressure-sensitive adhesives are widely used as the pressure-sensitive adhesive of the non-adhesive force, when the optical film is cut to a predetermined size in accordance with the size of the display, the pressure-sensitive adhesive is torn by the edge blades and foreign substances (also referred to as pressure- There is a problem that it is easy to do. If such foreign matter is generated, problems such as process contamination and traces of pressed on the optical film occur. For this reason, there is a demand for a surface protective film which is less likely to generate foreign matter when the optical film to which the surface protective film is adhered is slit or cut. In addition, it is also possible to use a surface protective film (e.g., a polarizing plate having a prism sheet or an anti-glare treatment) having good affinity (wettability) for an optical film having a concavo-convex shape on its surface, .

As described above, a surface protective film using a polyurethane-based pressure-sensitive adhesive is used for a demand for a surface protective film which is less liable to generate a sticky mass during slits or terminations and has good affinity for various optical films.

2. Description of the Related Art In recent years, in a production process of a liquid crystal display panel, a circuit component such as a driver IC for controlling a display screen of a liquid crystal display panel by a peeling electrification voltage generated when a surface protective film adhered on an optical film is peeled and removed And the phenomenon that the orientation of the liquid crystal molecules is damaged is small.

Further, in order to reduce the power consumption of the liquid crystal display panel, the driving voltage of the liquid crystal material is lowered, and accordingly the breakdown voltage of the driver IC is lowered. In recent years, it has been required to set the peeling electrification voltage within the range of +0.7 kV to -0.7 kV.

A surface protective film using a pressure-sensitive adhesive layer containing an antistatic agent for suppressing the peeling electrification voltage has been proposed in order to prevent a problem caused by a high peeling electrification voltage when the surface protective film is peeled off from the optical film to be adhered .

For example, Patent Document 1 discloses an antistatic pressure-sensitive adhesive comprising a polyurethane having an alkylene oxide chain, an ionic compound and a trifunctional isocyanate compound. Patent Document 2 discloses a polyurethane pressure-sensitive adhesive composition for a surface protective film, which comprises at least one salt selected from the group consisting of alkali metal salts of super strong acid and alkaline earth metal salts. Patent Document 3 discloses a pressure-sensitive adhesive composition comprising an ionic liquid containing a fluoro organic anion and a polyurethane having a number average molecular weight of 5,000 or more, and a surface protective film using the pressure-sensitive adhesive composition.

Japanese Patent Application Laid-Open No. 2005-154491 Japanese Laid-Open Patent Publication No. 2006-182794 Japanese Patent Application Laid-Open No. 2007-277484

In the above Patent Documents 1 to 3, an antistatic agent is added in the pressure-sensitive adhesive layer. However, as the thickness of the pressure-sensitive adhesive layer becomes thicker, the amount of the antistatic agent transferred from the pressure-sensitive adhesive layer to the adherend with respect to the adherend to which the surface protective film is adhered increases There is a lot of concern. If the amount of the antistatic agent transferred to the adherend increases, the appearance quality of the optical film as the adherend may decrease, or the adherence characteristics of the surface protective film may change over time.

As described above, another problem arises when the thickness of the pressure-sensitive adhesive is reduced in order to reduce the change with time in the antistatic agent transferred from the pressure-sensitive adhesive layer to the adherend. For example, when the optical film is used for an optical film having irregularities on the surface, such as a polarizing plate subjected to anti-glare treatment for preventing flashing, the pressure sensitive adhesive can not follow the unevenness of the surface of the optical film, And the adhesive area of the pressure-sensitive adhesive is reduced, so that the adhesive force is lowered, and the surface protective film is peeled off or peeled during use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a pressure-sensitive adhesive sheet which is excellent in affinity (wettability) for an optical film having unevenness on the surface thereof, It is an object of the present invention to provide a surface protective film having little stain on an adherend, a low staining property on an adherend even after a lapse of time, and an excellent peeling electrification preventing performance without deterioration over time, and an optical component to which the stain adhered .

The present inventors have conducted extensive studies to solve this problem.

First, in order to reduce the contamination of the adherend and to reduce the change with time of the antistatic performance, it is necessary to reduce the amount of the antistatic agent added, which is presumed to be a cause of contaminating the adherend. However, when the addition amount of the antistatic agent is reduced, the peeling electrification voltage when peeling the surface protective film from the adherend becomes high. Here, the present inventors have studied a method of suppressing the peeling electrification voltage when the surface protective film is peeled off from the adherend without increasing the absolute amount of the antistatic agent added. As a result, it has been found that, instead of adding an antistatic agent into the pressure-sensitive adhesive composition and mixing them to form a pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition is coated and dried to laminate the pressure- It is possible to suppress the peeling electrification voltage when the film is peeled off from the optically-usable film as the adherend, thereby completing the present invention.

That is, in order to solve the above-described problems, the present invention relates to a method for producing a releasing film, comprising the steps of: forming a base film made of a resin having transparency on one side thereof with a polyurethane pressure- And an antistatic surface protective film laminated on the surface of the antistatic film.

Further, it is preferable that the antistatic agent layer contains an ionic compound.

Further, it is preferable that the antistatic agent layer contains an ionic compound which makes the alkali metal a cation.

The thickness of the antistatic agent layer is preferably 0.01 to 0.3 mu m.

The present invention also provides an optical component in which the antistatic surface protective film is bonded.

The surface protective film of the present invention is excellent in affinity (wettability) with respect to optical films having irregularities on the surface of the surface of the surface of the adherend, It is possible to provide a surface protective film having excellent anti-peeling and antistatic properties without deterioration with time, and an optical component to which the surface protective film is adhered.

Further, according to the surface protective film of the present invention, since it is possible to reliably protect the surface of the optical film, generation of defective products can be suppressed in the production process of the optical component, and productivity and yield can be improved .

1 is a cross-sectional view showing the concept of an antistatic surface protective film of the present invention.
2 is a cross-sectional view showing a state in which the release film is peeled off from the antistatic surface protective film of the present invention.
3 is a cross-sectional view showing one embodiment of the antistatic surface protective film of the present invention bonded to an optical component.

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

1 is a cross-sectional view showing the concept of an antistatic surface protective film of the present invention. In this antistatic surface protective film 10, a pressure-sensitive adhesive layer 2 not containing an antistatic agent is formed on the surface of one side of the transparent base film 1. An antistatic agent layer 3 in which an antistatic agent containing material is present is formed on the surface of the pressure sensitive adhesive layer 2 and a release film 4 having been subjected to a release treatment is bonded to the surface of the antistatic agent layer 3 .

As the base film (1) used in the antistatic surface protective film (10) according to the present invention, a base film made of a resin having transparency and flexibility is used. Thus, the appearance of the optical component can be inspected with the antistatic surface protective film adhered to the optical component as the adherend. The transparent resin film 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, films made of other resins can be used as long as they have the necessary strength and optical suitability. The base film (1) may be a non-oriented film or a uniaxially or biaxially oriented film. The stretching magnification of the stretched film or the orientation angle in the axial direction formed by crystallization of the stretched film may be controlled to a specific value.

The thickness of the base film (1) used in the antistatic surface protective film (10) according to the present invention is not particularly limited. For example, a thickness of about 12 to 100 m is preferable. Further, if the thickness of the base film 1 is about 20 to 50 mu m, it is easy to handle and more preferable.

If necessary, an antifouling layer, antistatic layer, anti-scratch hard coat layer, or the like for preventing surface contamination can be formed on the surface of the base film 1 opposite to the surface on which the pressure-sensitive adhesive layer 2 is formed. Further, the surface of the base film 1 may be subjected to easy adhesion treatment such as surface modification by corona discharge, application of an anchor coat, and the like.

The pressure-sensitive adhesive layer (2) used in the antistatic surface protective film (10) according to the present invention can be easily peeled off from the adherend after the adherend is adhered to the surface of the adherend, It is difficult to contaminate the adhesive. In addition, it is preferable to form a pressure-sensitive adhesive layer using a polyurethane-based pressure-sensitive adhesive composition, since the occurrence of a mass of pressure-sensitive adhesive during the termination is small and the wettability to an adherend such as an optical film is good.

The polyurethane based pressure sensitive adhesive is a polyurethane resin composed of a polyol component and a polyisocyanate component and may be selected in consideration of adhesiveness, wettability, adherend staining property, etc., and the polyol component and the polyisocyanate component are not particularly limited. The polyurethane resin may be used singly or in combination of two or more kinds.

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

As the polyisocyanate component, an aliphatic polyisocyanate, an alicyclic polyisocyanate, an aromatic polyisocyanate, a multimer of a diisocyanate, and the like are used. These polyisocyanate components may be used alone or in combination of two or more.

Examples of commercially available products of polyurethane-series pressure-sensitive adhesives include Saiabain (registered trademark) SH-101, SH-101M, SP-205, SP-220 (manufactured by Toyochem), ARAKOTE (registered trademark) FT100, FT200 Ltd.), UN1175 and UN1176 (manufactured by Daido Chemical Industry Co., Ltd.), and the like. The pressure-sensitive adhesive layer may be one obtained by crosslinking or curing the polyurethane pressure-sensitive adhesive.

The thickness of the pressure-sensitive adhesive layer (2) used in the antistatic surface protective film (10) according to the present invention is not particularly limited. For example, the thickness is preferably about 5 to 40 m, Is more preferable.

The pressure-sensitive adhesive layer (2) may be formed on the surface of the base film (1) by a known method. Specifically, known coating methods such as reverse coating, comma coating, gravure coating, slot die coating, Meyer bar coating and air knife coating can be used.

The antistatic agent-containing material for constituting the antistatic agent layer 3 used in the antistatic surface protective film 10 according to the present invention may be an antistatic agent alone or a mixture of an antistatic agent and various resins. As the antistatic agent, an ionic compound is preferable. Examples of the resin used for the mixture of the antistatic agent and various resins include a polyester resin, a polyamide resin, a polyurethane resin, a polyolefin resin, a polyvinyl butyral resin, a polyvinyl alcohol resin, a polyvinyl acetate resin, A resin, a silicone resin, and a fluororesin.

The ionic compound is an ionic compound having a cation and an anion. Examples of the cation include an organic cation or an inorganic cation such as alkali metal cation, pyridinium cation, imidazolium cation, pyrimidinium cation, pyrazolium cation, pyrrolidinium cation, ammonium cation Etc., phosphonium cation, sulfonium cation, and the like. The nitrogen atom onium cation may have an organic group such as an alkyl group or a substituent. Preferably a quaternary nitrogen atom onium cation, a quaternary pyridinium cation or a quaternary pyridinium cation such as 1-alkyl pyridinium (the carbon atom at the 2-6 position may have a substituent or may be unsubstituted) - dialkyl imidazolium (quaternary imidazolium cation, such as the carbon atoms at the 2, 4 and 5 positions may have a substituent or may be unsubstituted), N-alkylpyrimidinium (2-position and 4- Position carbon atom may have a substituent or may be unsubstituted), 1,2-dialkylpyrazolium (the carbon atom at the 3-5 position may have a substituent, Quaternary pyrrolidinium cation such as quaternary pyrazolium cation, such as 1,1-dialkylpyrrolidinium (the carbon atom at 2-5 position may have a substituent or may be unsubstituted) And quaternary ammonium cation such as quaternium, tetraalkylammonium and the like. Examples of the phosphonium cation include phosphonium cation that has an organic group such as tetraalkylphosphonium. Examples of the sulfonium cation include sulfonium cationes having an organic group such as trialkylsulfonium.

Further, the anion is an organic anion or an inorganic anion, for _{example, C n H 2n + 1 COO} -, C n F 2n + 1 COO -, NO 3 -, C n F 2n + 1 SO 3 -, (C n F 2n + 1 SO 2) ^{_{2 n -, (C n F}} 2n + 1 SO 2) 3 C -, RC 6 H 4 SO 3 -, PO 4 3-, AlCl 4 -, Al 2 Cl 7 -, ClO 4 -, BF 4 -, PF 6 - , AsF ₆ ^- , SbF ₆ ^- , SCN ^- and the like. These ionic compounds may be used alone or in combination of two or more. To stabilize the ionic material, a compound containing a polyoxyalkylene structure may be added. In these formulas, subscript n is an integer of 0 or more. When n = 0, it corresponds to HCOO ^- , (FSO ₂ ) ₂ N ^- and so on.

Among them, an ionic compound (alkali metal salt) having an alkali metal cation as a cation is preferable. Examples of the alkali metal salts include metal salts of lithium, sodium and potassium. Specifically, for example, a cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ and a cation selected from Cl ^- , Br ^- , I ^- , BF ₄ ^- , PF ₆ ^- , SCN ^- , ClO ₄ ^- , CF ₃ SO ₃ ^- , (FSO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₂ N ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- and (CF ₃ SO ₂ ) ₃ C ^- Is used. Among _{others, LiBr, LiI, LiBF 4,} LiPF 6, LiSCN, LiClO 4, LiCF 3 SO 3, Li (FSO 2) 2 N, Li (CF 3 SO 2) 2 N, Li (C 2 F 5 SO 2 ) ₂ N, and Li (CF ₃ SO ₂ ) ₃ C are preferably used. These alkali metal salts may be used alone or in combination of two or more. To stabilize the ionic material, a compound containing a polyoxyalkylene structure may be added.

The thickness of the coating film after drying of the antistatic agent layer 3 may be determined in consideration of the kind of the antistatic agent, its antistatic property and the stain on the adherend, but is preferably 0.3 탆 or less. When the thickness of the antistatic agent layer 3 exceeds 0.3 占 퐉, when the surface protective film is adhered to the adherend, the component of the pressure sensitive adhesive composition is exposed from the resin forming the antistatic agent layer to the interface between the surface protective film and the adherend And the adhesive force of the pressure-sensitive adhesive layer 2 does not reach a predetermined value, which is not preferable. The thickness of the antistatic agent layer 3 is, for example, 0.01 to 0.3 mu m.

In view of the excellent operability in peeling off the antistatic surface protective film 10 (more specifically, the antistatic surface protective film 11 obtained by peeling off the release film shown in Fig. 2) from the adherend, It is preferable that the peel strength (adhesive force) when the film 10 is peeled off from the surface of the adherend is an adhesive strength of about 0.03 to 0.3 N / 25 mm.

In view of the excellent operability in peeling off the release film 4 from the antistatic surface protective film 10, the peeling force at the time of peeling off the release film 4 from the antistatic agent layer 3 is higher than the release rate 0.3 m / min and a peeling angle of 180 deg., it is preferable that the thickness is 0.005 to 0.3 N / 50 mm.

In the antistatic surface protective film 10 according to the present invention, the method for forming the antistatic agent layer 3 on the surface of the pressure-sensitive adhesive layer 2 is not particularly limited. For example, a method of incorporating the antistatic agent-containing material into the release agent layer of the release film 4 and transferring the release agent to the pressure-sensitive adhesive layer 2 when the release film 4 is adhered to the pressure-sensitive adhesive layer 2, (2) a method of printing the antistatic agent-containing material on the surface of the pressure-sensitive adhesive layer 2, (3) a method of applying the antistatic agent-containing material on the surface of the pressure-sensitive adhesive layer 2, and the like. The antistatic agent-containing material may be printed or applied uniformly or may be printed or applied in a specific pattern. The adhesion of the pressure-sensitive adhesive layer to the adherend of the antistatic surface protective film, and the like. The printing or application method of the antistatic agent-containing material may be carried out by a known method.

The resin used for the release film 4 used in the antistatic surface protective film 10 shown in Fig. 1 is not particularly limited. As the release film 4, for example, a resin film such as a polyester film, a polyamide film, a polyethylene film, a polypropylene film and a polyimide film may be coated with a silicone release agent, a long chain alkyl group- A release film treated with a release agent, and a release film obtained by forming a resin having a releasing property such as polyethylene resin, polypropylene resin, polymethylpentene resin, and fluorine resin.

The thickness of the release film is not particularly limited. For example, the thickness of the release film is preferably about 12 to 100 mu m, and the thickness of about 20 to 50 mu m is easier to handle and more preferable.

2 is a cross-sectional view showing a state in which the release film is peeled off from the antistatic surface protective film of the present invention. In the antistatic surface protective film 11 from which the release film shown in Fig. 2 is peeled, the antistatic agent layer 3 is formed on the surface of the pressure-sensitive adhesive layer 2. [

3 is a cross-sectional view showing an embodiment in which an antistatic surface protective film of the present invention is applied to an optical component.

In the antistatic surface protective film 10 of the present invention, the peeling film 4 is peeled off and the antistatic agent layer 3 is exposed (the antistatic surface protective film 11 in Fig. 2) And is adhered to the optical component 5 as an adherend with the antistatic agent layer 3 interposed therebetween.

That is, FIG. 3 shows an optical component 20 to which an antistatic surface protective film 11 in a state of peeling the release film 4 from the antistatic surface protective film 10 of the present invention is bonded. Examples of the optical component include optical films such as a polarizing plate, a retardation plate, a lens film, a polarizing plate serving as a retardation plate, and a polarizing plate serving also 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 and an optical system device of various instruments. 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. Particularly, it is preferable to use an anti-fouling film which is adhered to an antifouling treated surface of an optical film such as a low reflection polarizing plate (LR polarizing plate) and an anti-glare low reflection polarizing plate (AG-LR polarizing plate) whose surface is treated with a silicone compound, It can be preferably used as an anti-surface protective film.

When the antistatic surface protective film 11 in a state in which the release film 4 is peeled from the antistatic surface protective film 10 of the present invention is peeled off from the optical component (optical film) It can be suppressed sufficiently low. Therefore, there is no fear of destroying the circuit components such as the driver IC, the TFT element, and the gate line driving circuit, and the production efficiency in the process of manufacturing the liquid crystal display panel and the like can be increased, and the reliability of the production process can be maintained.

Example

Next, the present invention will be described in detail by examples.

(Example 1)

(Preparation of antistatic surface protective film)

100 parts by weight of a polyurethane pressure-sensitive adhesive (Arakoto (registered trademark) FT200, manufactured by Arakawa Chemical Industries, Ltd., content of non-volatile components of the pressure-sensitive adhesive of 40% by weight) And 5.7 parts by weight of a curing agent nonvolatile ingredient (trade name: Aracat (registered trademark) CL2503, manufactured by Arakawa Chemical Industries, Ltd., content: 40% by weight) And then dried in a hot air circulating oven at 100 캜 for 2 minutes to form a pressure-sensitive adhesive layer. Thereafter, an ethyl acetate solution of lithium bis (trifluoromethanesulfonyl) imide as an antistatic agent was applied to the surface of the pressure-sensitive adhesive layer using Meyer Bar No. 4 so that the thickness of the antistatic agent layer after drying was 0.1 탆 Thereafter, it was heated and dried in a hot-air circulating oven at 100 ° C for 2 minutes to prepare a sample having an antistatic agent layer formed on the surface of the pressure-sensitive adhesive layer. A release film (DIAFOLY MRF38 manufactured by Mitsubishi Plastics, Inc., a polyethylene terephthalate film having a thickness of 38 m treated with a silicone release agent) was applied to the surface of the pressure-sensitive adhesive layer of this sample to obtain an antistatic surface A protective film was obtained.

(Example 2)

The antistatic surface protective film of Example 2 was obtained in the same manner as in Example 1 except that the antistatic agent of Example 1 was lithium bis (fluorosulfonyl) imide and the antistatic agent layer after drying had a thickness of 0.05 占 퐉. ≪ / RTI >

(Example 3)

An antistatic surface protective film of Example 3 was obtained in the same manner as in Example 1 except that the thickness of the antistatic agent layer of Example 1 after drying was 0.3 占 퐉.

The procedure of Example 1 was repeated except that the antistatic agent of Example 1 was replaced with tri-n-butylmethylammonium bistrifluoromethanesulfonimide (manufactured by 3M Japan Co., Ltd., product number: FC-4400) An antistatic surface protective film was obtained.

(Comparative Example 1)

A pressure-sensitive adhesive composition prepared by mixing an antistatic agent mixed with an antistatic agent of Example 1 at a solid content ratio of 100: 1.5 in the pressure-sensitive adhesive composition of Example 1 instead of laminating the antistatic agent layer on the pressure- An antistatic surface protective film of Comparative Example 1 was obtained in the same manner as in Example 1 except that the coating was applied so as to have a thickness of 20 탆.

(Comparative Example 2)

A surface protective film of Comparative Example 2 was obtained in the same manner as in Example 1 except that no antistatic agent layer was formed.

(Comparative Example 3)

An antistatic surface protective film of Comparative Example 3 was obtained in the same manner as in Example 1 except that the thickness of the antistatic agent layer after drying was 0.5 탆.

Hereinafter, the evaluation test method and results are shown.

≪ Method of measuring peel strength of release film >

A sample of the antistatic surface protective film is cut to a width of 50 mm and a length of 150 mm. The strength of the peeled film peeled off from the antistatic agent layer in the direction of 180 ° at a peeling rate of 300 mm / min under a test environment of 23 ° C × 50% RH was measured using a tensile tester, and the peel strength (N / 50 mm).

(Method for measuring the surface resistivity of the surface of the antistatic agent)

After the release film was peeled off from the sample of the antistatic surface protective film, the surface resistivity of the surface of the antistatic agent layer was measured by using a high resistance resistivity meter (Hirestr (registered trademark) -UP manufactured by Mitsubishi Chemical Corporation) Measurement is made under the condition of a voltage of 100 V and a measurement time of 30 seconds.

≪ Method of measuring adhesion of antistatic surface protective film >

An anti-glare low reflection polarizing plate (AG-LR polarizing plate) was bonded to the surface of the glass plate using a coater. Thereafter, an antistatic surface protective film cut to a width of 25 mm was applied to the surface of the polarizing plate, and then stored for 1 day under a test environment of 23 DEG C x 50% RH. Thereafter, the strength when the antistatic surface protective film was peeled off in the direction of 180 DEG at a peeling speed of 300 mm / min was measured using a tensile tester, and this was regarded as an adhesive force (N / 25 mm).

≪ Method of measuring peeling electrification voltage of antistatic surface protective film >

An anti-glare low reflection polarizing plate (AG-LR polarizing plate) was bonded to the surface of the glass plate using a coater. Thereafter, an antistatic surface protective film cut to a width of 25 mm was applied to the surface of the polarizing plate through an antistatic agent layer, and then stored for 1 day under a test environment of 23 占 폚 占 50% RH. Thereafter, while peeling off the antistatic surface protective film at a peeling rate of 40 m per minute using a high-speed peeling tester (manufactured by Tester Industries), the surface potential of the surface of the polarizing plate was measured every 10 ms using a surface electrometer The maximum value of the absolute value of the surface potential when measured was taken as the peeling electromotive force (kV).

<Method of confirming surface staining property of antistatic surface protective film>

An anti-glare low reflection polarizing plate (AG-LR polarizing plate) was bonded to the surface of the glass plate using a coater. Thereafter, an antistatic surface protective film cut to a width of 25 mm was applied to the surface of the polarizing plate through an antistatic agent layer, and then stored for 3 days and 30 days under a test environment of 23 占 폚 占 50% RH. Thereafter, the antistatic surface protective film was peeled off, and the staining property of the surface of the polarizing plate was visually observed. As a criterion of the surface staining property, the case where no staining was observed on the polarizing plate was evaluated as (o), and the case where the staining on the polarizing plate was confirmed as (x).

The obtained antistatic surface protective films of Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1 and Table 2, respectively. "LiFSI" is lithium bis (fluorosulfonyl) imide, "FC-4400" is tri-n-butyl methyl ammonium bistrifluoro Methane sulfone imide, respectively. "5.9E9" of the surface resistivity of the surface of the antistatic agent layer means 5.9 × 10 ⁹ and "overrange" means that the surface resistivity (Ω / □) exceeds the upper limit of measurement (1.0 × 10 ¹³ or more) Means impossible to measure.

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

The antistatic surface protective film of Examples 1 to 4 according to the present invention had an appropriate adhesion even in the bonding via the antistatic agent layer and was free from contamination to the surface of the adherend and also the antistatic surface protective film was peeled from the adherend The peeling electrification voltage is low.

On the other hand, the surface protective film of Comparative Example 1, in which the antistatic agent was uniformly mixed with the pressure-sensitive adhesive layer, was good because the peeling electrification voltage when the surface protective film was peeled off from the adherend was low. However, The fecal matter was worsened. Further, the surface protective film of Comparative Example 2 in which the antistatic agent layer was not formed on the surface of the pressure-sensitive adhesive layer had a higher peeling electrification voltage when the surface protective film was peeled from the adherend. In Comparative Example 3 in which the thickness of the antistatic agent layer was increased, the peeling electrification voltage when the surface protective film was peeled off from the adherend was low because of the low degree of contamination to the adherend after peeling.

The antistatic surface protective film of the present invention can be used to protect the surface of an antireflection film or the like in a production process of an optical film such as a polarizing plate, a retardation film, and a lens film, . Further, the surface protective film of the present invention can reduce the amount of static electricity generated when peeling off from the adherend, and furthermore, the peeling electrification preventing performance is less changed with time, the adherend is less contaminated, Can be improved in the yield of industrial use.

One… Base film, 2 ... Adhesive layer, 3 ... Antistatic agent layer, 4 ... Peeling film, 5 ... Optical components, 10 ... Antistatic surface protection film, 11 ... Antistatic surface protection film with exfoliating film, 20 ... Antistatic surface protective film.

Claims (3)

A polyurethane pressure-sensitive adhesive layer not containing an antistatic agent and an antistatic agent layer composed only of an antistatic agent are stacked in this order on one surface of a base film made of a resin having transparency,
Wherein the antistatic agent is a lithium salt,
Wherein the antistatic agent layer has a thickness of 0.01 to 0.3 mu m,
Wherein the antistatic agent layer is formed by transferring a release film formed by laminating a release agent containing a release agent and an antistatic agent on one side of a resin film to the polyurethane pressure sensitive adhesive layer when the release film is applied to the polyurethane pressure sensitive adhesive layer Wherein the antistatic surface protective film is a film having antistatic properties. The method according to claim 1,
That the antistatic agent _{LiBr, LiI, LiBF 4, LiPF} 6, LiSCN, LiClO 4, LiCF 3 SO 3, Li (FSO 2) 2 N, Li (CF 3 SO 2) 2 N, Li (C 2 F 5 SO 2 ) ₂ N, and Li (CF ₃ SO ₂ ) ₃ C. The antistatic surface protective film according to claim 1, An optical component in which the antistatic surface protective film of claim 1 or 2 is bonded.

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