JP2022062003A - Antistatic surface protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antistatic surface protective film less in contamination to an adherent, and, having excellent release antistatic performance without deteriorating.

SOLUTION: On one surface of the substrate, an adhesive layer 2 made of an acrylic polymer of a copolymer obtained by copolymerizing (a1) 1 to 30 pts.mass of (meth)acrylic acid ester monomer of C1 to C4 carbon s of an alkyl group, (a2) 70 to 99 pts.mass of (meth)acrylic acid ester monomer of C5 to C18 of an alkyl group, and (B) 0.1 to 12 pts.mass of a copolymerizable monomer containing a hydroxy group, further the adhesive layer 2 obtained by crosslinking an adhesive composition containing (C) a divalent or more valent isocyanate compound, (D) a crosslinking accelerator, and (E) a keto-enol tautomeric isomer compound, and not containing an antistatic agent is formed, on its surface, a release film 5 in which a release layer 4 containing an antistatic agent is laminated on one surface of the resin film is laminated is adhered.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an antistatic surface protective film. More specifically, with respect to a method for manufacturing an antistatic surface protective film having antistatic performance and an antistatic surface protective film, the adherend is less contaminated and has excellent peeling antistatic performance without deterioration over time. A method for manufacturing an antistatic surface protective film and an antistatic surface protective film are provided.

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 optical products such as displays using them. A surface protective film is attached to the surface of the optical film to prevent the surface from being soiled or scratched in a subsequent step. The appearance inspection of the optical film as a product may be performed with the surface protective film attached to the optical film in order to save the trouble of peeling off the surface protective film and attaching it again to improve work efficiency.
Conventionally, a surface protective film provided with an adhesive layer on one side of a base film has been generally used in order to prevent scratches and stains from adhering in the manufacturing process of optical products. The surface protective film is attached to the optical film via a pressure-sensitive adhesive layer having a slight adhesive strength. The reason why the adhesive layer has a slight adhesive strength is that the used surface protective film can be easily peeled off when it is peeled off from the surface of the optical film, and the adhesive is an adherend of the product. This is to prevent it from adhering to the optical film and remaining (so-called adhesive residue is prevented).

In recent years, in the production process of a liquid crystal display panel, the display screen of the liquid crystal display panel is controlled by the peeling band voltage generated when the surface protective film bonded on the optical film is peeled off and removed. Although the number of occurrences is small, the phenomenon that circuit parts such as driver ICs are destroyed and the phenomenon that the orientation of liquid crystal molecules is damaged are occurring.
Further, in order to reduce the power consumption of the liquid crystal display panel, the driving voltage of the liquid crystal material is getting lower, and the breaking voltage of the driver IC is also getting lower accordingly. Recently, it has been required to keep the peeling band voltage in the range of +0.7 kV to −0.7 kV.
Therefore, when the surface protective film is peeled off from the optical film which is the adherend, a pressure-sensitive adhesive layer containing an antistatic agent for suppressing the peeling band voltage is prevented in order to prevent a problem due to a high peeling band voltage. A surface protective film using the above has been proposed.

For example, Patent Document 1 discloses a surface protective film using a pressure-sensitive adhesive composed of an alkyltrimethylammonium salt, a hydroxyl group-containing acrylic polymer, and a polyisocyanate.
Further, Patent Document 2 discloses a pressure-sensitive adhesive composition composed of an ionic liquid and an acrylic polymer having an acid value of 1.0 or less, and pressure-sensitive adhesive sheets using the same.
Further, Patent Document 3 discloses an adhesive composition composed of an acrylic polymer, a polyether polyol compound, an alkali metal salt treated with an anion-adsorbing compound, and a surface protection film using the same.
Further, Patent Document 4 discloses a pressure-sensitive adhesive composition composed of an ionic liquid, an alkali metal salt, a polymer having a glass transition temperature of 0 ° C. or lower, and a surface protective film using the same.
Further, Patent Documents 5 and 6 show that a polyether-modified silicone is mixed in the pressure-sensitive adhesive layer of the surface protective film.

Japanese Unexamined Patent Publication No. 2005-131957 Japanese Unexamined Patent Publication No. 2005-330464 Japanese Unexamined Patent Publication No. 2005-314476 Japanese Unexamined Patent Publication No. 2006-152235 Japanese Unexamined Patent Publication No. 2009-275128 Japanese Patent No. 4537450

In the above Patent Documents 1 to 4, an antistatic agent is added to the inside of the pressure-sensitive adhesive layer, but the surface protective film is bonded as the thickness of the pressure-sensitive adhesive layer increases and as the elapsed time elapses. The amount of the antistatic agent transferred from the pressure-sensitive adhesive layer to the adherend increases with respect to the adherend. Further, in optical films such as LR (Low Reflective) polarizing plates and AG (AntiGale) -LR polarizing plates, the surface of the optical film is treated with a silicone compound, a fluorine compound, or the like to prevent stains. When the surface protective film used for the optical film is peeled off from the optical film as an adherend, the peeling band voltage becomes high.

Further, when the polyether-modified silicone described in Patent Documents 5 and 6 is mixed in the pressure-sensitive adhesive layer, it is difficult to finely adjust the adhesive strength of the surface protective film. Further, since the polyether-modified silicone is mixed in the pressure-sensitive adhesive layer, when the conditions for applying and drying the pressure-sensitive adhesive composition on the base film change, the pressure-sensitive adhesive layer on which the surface protective film is formed is formed. Surface properties change subtly. Further, from the viewpoint of protecting the surface of the optical film, the thickness of the pressure-sensitive adhesive layer cannot be made extremely thin. Therefore, it is necessary to increase the amount of the polyether-modified silicone mixed in the pressure-sensitive adhesive layer according to the thickness of the pressure-sensitive adhesive layer. The contamination of the adherend changes.

In recent years, with the spread of 3D displays (stereoscopic displays), there are those in which an FPR (Film Patterned Renderer) film is attached to the surface of an optical film such as a polarizing plate. After peeling off the surface protective film attached to the surface of the optical film such as a polarizing plate, the FPR film is attached. However, if the surface of an optical film such as a polarizing plate is contaminated with an adhesive or an antistatic agent used for the surface protective film, there is a problem that the FPR film is difficult to adhere. Therefore, the surface protective film used for this purpose is required to have less contamination on the adherend.

On the other hand, in some liquid crystal panel makers, as a method of evaluating the contamination of the surface protective film on the adherend, the surface protective film attached to the optical film such as a polarizing plate is once peeled off and air bubbles are mixed. A method is adopted in which the reattached film is heat-treated under predetermined conditions, and then the surface protective film is peeled off to observe the surface of the adherend. In such an evaluation method, even if the surface contamination of the adherend is very small, the difference in the surface contamination of the adherend is between the portion where air bubbles are mixed and the portion where the adhesive of the surface protective film is in contact. If there is, it remains as a trace of bubbles (sometimes called bubble stains). Therefore, it is a very strict evaluation method as a method for evaluating the contamination of the surface of the adherend. In recent years, even as a result of determination by such a strict evaluation method, there is a demand for a surface protective film that does not have a problem of stainability on the surface of the adherend. However, it has been difficult to solve the problem with the conventionally proposed surface protective film using an adhesive layer containing an antistatic agent.

Therefore, there is a need for a surface protective film used for an optical film, which has very little contamination on the adherend and whose stainability on the adherend does not change with time. Further, there is a demand for a surface protective film in which the peeling band voltage at the time of peeling from the adherend is suppressed to a low level.

The present inventors have diligently studied to solve this problem.
In order to reduce the contamination of the adherend and the change in antistatic performance over time, it is necessary to reduce the amount of the antistatic agent added, which is presumed to be the cause of contaminating the adherend. However, when the amount of the antistatic agent added is reduced, the peeling band voltage when the surface protective film is peeled from the adherend becomes high. The present inventors have studied a method of suppressing the peeling band voltage when the surface protective film is peeled from the adherend without increasing the absolute amount of the antistatic agent added. As a result, instead of adding and mixing an antistatic agent in the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition is coated and dried to laminate the pressure-sensitive adhesive layer, and then the pressure-sensitive adhesive is applied. We have found that by imparting an appropriate amount of an antistatic agent component to the surface of the layer, the peeling band voltage when the surface protective film is peeled from the optical film as an adherend can be suppressed to a low level, and the present invention has been made. Was completed.

The present invention has been made in view of the above circumstances, and is a method for producing an antistatic surface protective film, which has less contamination on the adherend and has excellent peeling antistatic performance without deterioration over time, and charging. An object of the present invention is to provide a preventive surface protective film.

In order to solve the above problems, in the antistatic surface protective film of the present invention, an appropriate amount of antistatic agent is applied to the surface of the pressure-sensitive adhesive layer after the pressure-sensitive adhesive composition is applied and dried to laminate the pressure-sensitive adhesive layer. The technical idea is to keep the contamination property to the adherend low and to keep the peeling band voltage low when peeling from the optical film which is the adherend.

In order to solve the above problems, the present invention is a method for producing an antistatic surface protective film, wherein the following steps (1) to (3), step (1): a pressure-sensitive adhesive composition containing an acrylic polymer. In the acrylic polymer, the (a1) alkyl group has C1 to C1 to 100 parts by weight of the (meth) acrylic acid ester monomer having (A) alkyl groups having C1 to C18 carbon atoms. At least 1 to 30 parts by weight of at least one (meth) acrylic acid ester monomer of C4 and 70 to 99 parts by weight of at least one (meth) acrylic acid ester monomer having (a2) alkyl groups having C5 to C18 carbon atoms. From the acrylic polymer of the copolymer obtained by copolymerizing at least one of (B) a copolymerizable monomer containing a hydroxyl group with 0.1 to 12 parts by weight as a copolymerizable monomer group. The acrylic polymer does not contain a copolymerizable monomer containing a carboxyl group and a nitrogen-containing vinyl monomer containing no hydroxyl group, and the pressure-sensitive adhesive composition further comprises (C) a bifunctional or higher functional isocyanate compound. A step of preparing a pressure-sensitive adhesive composition containing (D) a cross-linking accelerator and (E) a ketoenol copolymer compound, and a step (2): a base film made of a transparent resin. A step of forming a pressure-sensitive adhesive layer obtained by cross-linking the pressure-sensitive adhesive composition on one side, and a step (3): a release agent layer containing an antioxidant on one side of a resin film is laminated on the surface of the pressure-sensitive adhesive layer. The steps (1) to (3) of the steps (1) to (3), wherein the peeled film is bonded via the peeling agent layer and the antistatic agent of the peeling agent layer is transferred to the surface of the pressure-sensitive adhesive layer. The release agent layer is formed of a resin composition containing a release agent containing a dimethylpolysiloxane as a main component and an antistatic agent, and the pressure-sensitive adhesive layer is subjected to a low-reflection surface treatment. The peeling band voltage at the time of peeling after being bonded to the polymerized polarizing plate is ± 0.6 kV or less, and the pressure-sensitive adhesive layer is bonded to the polymer subjected to the low-reflection surface treatment and then peeled off. Provided is a method for producing an antistatic surface protective film, which is characterized by having good stainability when the polymer is used.

Further, in the pressure-sensitive adhesive composition, the polyalkylene glycol mono (F) having an average number of repetitions of the alkylene oxide constituting the polyalkylene glycol chain of 3 to 14 and a diester content of 0.2% or less in the monomer (F). Meta) It is preferable to contain an acrylic acid ester monomer.

Further, it is preferable that the antistatic agent in the release agent layer is an alkali metal salt.

Further, in order to solve the above problems, in the present invention, a pressure-sensitive adhesive layer obtained by cross-linking a pressure-sensitive adhesive composition containing an acrylic polymer is formed on one side of a base film made of a transparent resin. A release film obtained by laminating a release agent layer containing an antioxidant on one side of a resin film on the surface of the pressure-sensitive adhesive layer is an antistatic surface protection film bonded via the release agent layer. The acrylic polymer is copolymerizable with (A) a total of 100 parts by weight of at least one (meth) acrylic acid ester monomer having an alkyl group having C1 to C18 and (B) a hydroxyl group. It is composed of an acrylic polymer of a copolymer obtained by copolymerizing at least one kind of monomer with 0.1 to 12 parts by weight in total, and the (A) alkyl group has (meth) carbon atoms of C1 to C18. Of the total of 100 parts by weight of at least one of the acrylic acid ester monomers, the total of at least one of the (meth) acrylic acid ester monomers having (a1) alkyl groups having C1 to C4 is 1 to 30 parts by weight. , (A2) The total of at least one of the (meth) acrylic acid ester monomers having C5 to C18 carbon atoms in the alkyl group is contained in a proportion of 70 to 99 parts by weight, and the acrylic polymer is carboxyl. A copolymerizable monomer containing a group and a nitrogen-containing vinyl monomer not containing a hydroxyl group are not copolymerized, and the pressure-sensitive adhesive composition further comprises (C) a bifunctional or higher functional isocyanate compound and (D). A release agent containing a cross-linking accelerator and (E) a ketoenol copolymer compound and containing no antistatic agent, and the release agent layer containing dimethylpolysiloxane as a main component. It is formed of a resin composition containing a polyether-modified silicone which is a liquid silicone-based compound at 20 ° C. and an antistatic agent, and is peeled off from the surface of the pressure-sensitive adhesive layer of the antistatic surface protective film. When the film is peeled off, the antistatic agent of the release agent layer is transferred to the surface of the pressure-sensitive adhesive layer, and the antistatic surface protective film from which the release film is peeled off is covered with the pressure-sensitive adhesive layer. It is characterized in that when the pressure-sensitive adhesive layer is peeled off from the polarizing plate after being bonded to a polarizing plate subjected to a low-reflection surface treatment as a body, the surface of the polarizing plate is visually observed and there is no contamination. Provided is an antistatic surface protective film.

Further, the pressure-sensitive adhesive composition further constitutes (F) a polyalkylene glycol chain with respect to a total of 100 parts by weight of the (meth) acrylic acid ester monomer having (A) alkyl groups having C1 to C18 carbon atoms. The average number of repetitions of the alkylene oxide is 3 to 14, and the diester content in the monomer is 0.2% or less. The polyalkylene glycol mono (meth) acrylic acid ester monomer is contained in an amount of 0 to 50 parts by weight (however, even if it is not contained). Yes) is preferred.

Further, the (D) cross-linking accelerator is at least one selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound, and is 0. It is 001 to 0.5 parts by weight, contains 0.1 to 300 parts by weight of the (E) ketoenol chelate compound, and has a weight ratio of (E) / (D) of 70 to 1000. It is preferable to have.

Further, the copolymerizable monomer containing the (B) hydroxyl group is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxyethyl (meth). ) At least one selected from the compound group consisting of acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide, and the acrylic polymer. It is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight.

Further, as the (C) bifunctional or higher functional isocyanate compound, the bifunctional isocyanate compound is an acyclic aliphatic isocyanate compound, which is a compound produced by reacting a diisocyanate compound with a diol compound, and is a diisocyanate compound. Is an aliphatic diisocyanate, one selected from the compound group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate, and 2-methyl- as the diol compound. 1,3-Propanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, It consists of one selected from the compound group consisting of 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol, and polypropylene glycol, and is trifunctional. Examples of the isocyanate compound include an isocyanurate form of a hexamethylene diisocyanate compound, an isocyanurate form of an isophorone diisocyanate compound, an adduct form of a hexamethylene diisocyanate compound, an adduct form of an isophorone diisocyanate compound, a burette form of a hexamethylene diisocyanate compound, and a burette of an isophorone diisocyanate compound. Body, isocyanurate of tolylene diisocyanate compound, isocyanurate of xylylene diisocyanate compound, isocyanurate of hydrogenated xylylene diisocyanate compound, adduct of tolylene diisocyanate compound, adduct of xylylene diisocyanate compound, hydrogenated xiri It is composed of an adduct body of a range isocyanate compound, and is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer.

Further, in the pressure-sensitive adhesive composition, 1.0 part by weight or less (0 parts by weight) of the (H) polyether-modified siloxane compound having an HLB value of 7 to 15 with respect to 100 parts by weight of the acrylic polymer is used. Excludes), preferably included.

Further, it is preferable that the silicone-based compound in the release agent layer is a polyether-modified silicone.

Further, it is preferable that the antistatic agent in the release agent layer is an alkali metal salt.

Further, the antistatic agent in the release agent layer is a Li salt, and it is preferable that the antistatic agent is at least one selected from the compound group consisting of LiTFSI, LiFSI and LiTF.

The present invention also provides an optical film in which the antistatic surface protective film is bonded together with the release film peeled off.

The present invention also provides an optical component in which the antistatic surface protective film is bonded together with the release film peeled off.

The antistatic surface protective film of the present invention has less contamination on the adherend, and the low contamination property on the adherend does not change with time. Further, according to the present invention, even if the surface of the adherend, such as an LR polarizing plate or an AG-LR polarizing plate, is antifouling treated with a silicone compound or a fluorine compound, antistatic treatment is performed. It is possible to provide an antistatic surface protective film which can suppress the peeling band voltage generated when the surface protective film is peeled from an adherend to a low value and has excellent peeling antistatic performance without deterioration over time.
According to the antistatic surface protective film of the present invention, the surface of the optical film can be reliably protected, so that productivity and yield can be improved.

It is sectional drawing which showed the concept of the antistatic surface protective film of this invention. It is sectional drawing which shows the state which peeled off the release film from the antistatic surface protection film of this invention. It is sectional drawing which showed one of the Examples of the optical component of this invention.

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

As the base film 1 used in the antistatic surface protective film 10 according to the present invention, a base film made of a transparent and flexible resin is used. This makes it possible to inspect the appearance of the optical component in a state where the antistatic surface protective film is attached to the optical component which is an adherend. As the film made of a transparent resin used as the base film 1, a polyester film such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and polybutylene terephthalate is preferably used. In addition to the polyester film, a film made of another resin can be used as long as it has the required strength and optical aptitude. The base film 1 may be a non-stretched film or a uniaxially or biaxially stretched film. Further, the draw ratio of the stretched film and the axial orientation angle formed by the crystallization of the stretched film may be controlled to a specific value.
The thickness of the base film 1 used for the antistatic surface protective film 10 according to 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 easy to handle. , More preferred.
Further, if necessary, an antifouling layer, an antistatic layer, a scratch-preventing hard coat layer, etc. for preventing surface contamination are provided on the surface of the base film 1 opposite to the surface on which the adhesive layer 2 is formed. Can be provided. Further, the surface of the base film 1 may be subjected to an easy-adhesion treatment such as surface modification by corona discharge or application of an anchor coating agent.

Further, the adhesive layer 2 used in the antistatic surface protective film 10 according to the present invention is an adhesive that adheres to the surface of the adherend, can be easily peeled off after use, and does not easily contaminate the adherend. If it is not particularly limited, it is preferable to use an acrylic pressure-sensitive adhesive obtained by cross-linking a pressure-sensitive adhesive composition containing an acrylic polymer, in consideration of durability after bonding to an optical film. It is common.

In particular, the acrylic polymer is (A) a (meth) acrylic acid ester monomer having an alkyl group having a carbon number of C1 to C18, and (a1) a (meth) acrylic acid ester monomer having an alkyl group having a carbon number of C1 to C4. Copolymerizable with at least one type and (a2) at least one type of (meth) acrylic acid ester monomer having an alkyl group having C5 to C18 carbon atoms and (B) a hydroxyl group as a copolymerizable monomer group. A pressure-sensitive adhesive layer made of an acrylic polymer of a copolymer obtained by copolymerizing at least one kind of monomer is preferable.
As the copolymerizable monomer group, the polyalkylene glycol having an average number of repetitions of the alkylene oxide constituting the (F) polyalkylene glycol chain of 3 to 14 and a diester content of 0.2% or less in the monomer is further formed. It can contain a mono (meth) acrylic acid ester monomer.
The acrylic polymer preferably does not contain a copolymerizable monomer containing a carboxyl group and a nitrogen-containing vinyl monomer containing no hydroxyl group.
Further, a pressure-sensitive adhesive composition comprising (C) a bifunctional or higher functional isocyanate compound, (D) a cross-linking accelerator, and (E) a keto-enol tautomer compound in addition to the acrylic polymer. The agent layer is preferred.

Among the (meth) acrylic acid ester monomers having (A) alkyl groups having C1 to C18 carbon atoms, at least one of the (a1) alkyl group carbon atoms (meth) acrylic acid ester monomers having C1 to C4 carbon atoms is selected as one. Examples thereof include butyl (meth) acrylate, isobutyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and isopropyl (meth) acrylate.
Further, examples of the (meth) acrylic acid ester monomer having (a2) alkyl groups having C5 to C18 carbon atoms include pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, and isooctyl. (Meta) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (Meta) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, myristyl (meth) acrylate, isomyristyl (meth) acrylate, cetyl ( Examples thereof include meta) acrylate, isosetyl (meth) acrylate, stearyl (meth) acrylate, and isostearyl (meth) acrylate.
(A1) A (meth) acrylic acid ester monomer having an alkyl group having a carbon number of C1 to C4 with respect to a total of 100 parts by weight of a (meth) acrylic acid ester monomer having an alkyl group having a carbon number of C1 to C18. At least one kind is contained in an amount of 1 to 30 parts by weight, and at least one kind of (meth) acrylic acid ester monomer having (a2) an alkyl group having C5 to C18 carbon atoms is contained in a ratio of 70 to 99 parts by weight. It is more preferable that at least one of the above (a1) is contained in an amount of 5 to 25 parts by weight and at least one of the above (a2) is contained in a proportion of 75 to 95 parts by weight. It is particularly preferable that at least one of a1) is contained in an amount of 8 to 22 parts by weight and at least one of (a2) is contained in an amount of 78 to 92 parts by weight.

(B) Examples of the copolymerizable monomer containing a hydroxyl group include 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate. Examples thereof include hydroxyalkyl (meth) acrylates such as N-hydroxy (meth) acrylamide, hydroxyl group-containing (meth) acrylamides such as N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl (meth) acrylamide.
8-Hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) ) At least one selected from the compound group consisting of acrylamide and N-hydroxyethyl (meth) acrylamide is preferable. These (B) hydroxyl group-containing copolymerizable monomers do not have a polyalkylene glycol chain, unlike the (F) polyalkylene glycol mono (meth) acrylic acid ester monomer described later.
(A) At least one copolymerizable monomer containing a hydroxyl group (B) is 0.1 to 0.1 to 100 parts by weight in total of the (meth) acrylic acid ester monomer having an alkyl group having C1 to C18 carbon atoms. The copolymerization is preferably carried out at a ratio of 12 parts by weight, more preferably 0.1 to 9.5 parts by weight, and particularly preferably 0.3 to 8 parts by weight.
Further, when the total amount of the acrylic polymers is 100 parts by weight, it is preferable that the copolymerizable monomer containing the (B) hydroxyl group is contained in a proportion of 0.1 to 10 parts by weight. It is more preferably 1 to 8.5 parts by weight, and particularly preferably 0.3 to 7.5 parts by weight.

(C) The bifunctional or higher functional isocyanate compound may be at least one or more selected from polyisocyanate compounds having at least two or more isocyanate (NCO) groups in one molecule. The polyisocyanate compound is classified into an aliphatic isocyanate, an aromatic isocyanate, an acyclic isocyanate, an alicyclic isocyanate and the like, but any of them may be used. Specific examples of the polyisocyanate compound include aliphatic isocyanate compounds such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and trimethylhexamethylene diisocyanate (TMDI), diphenylmethane diisocyanate (MDI), and xylylene diisocyanate (XDI). , Aromatic isocyanate compounds such as hydrogenated xylylene diisocyanate (H6XDI), dimethyldiphenylenedi isocyanate (TOID), and tolylene diisocyanate (TDI).
Examples of the trifunctional or higher functional isocyanate compound include a burette-modified form of a bifunctional isocyanate compound (a compound having two NCO groups in one molecule), an isocyanurate-modified form, and trivalent or higher valents such as trimethylolpropane (TMP) and glycerin. Examples thereof include an adduct form (polyol modified form) with a polyol (a compound having at least 3 or more OH groups in one molecule).
As the (C) bifunctional or higher functional isocyanate compound, it is also possible to use only the (C-1) trifunctional isocyanate compound or only the (C-2) bifunctional isocyanate compound. It is also possible to use the (C-1) trifunctional isocyanate compound and the (C-2) bifunctional isocyanate compound in combination.

Further, as the (C-1) trifunctional isocyanate compound used in the present invention, an isocyanurate form of a hexamethylene diisocyanate compound, an isocyanurate form of an isophorone diisocyanate compound, an adduct body of a hexamethylene diisocyanate compound, an adduct body of an isophorone diisocyanate compound, and the like. At least one selected from the (C-1-1) first aliphatic isocyanate compound group consisting of a burette of a hexamethylene diisocyanate compound and a burette of an isophorone diisocyanate compound, and tolylene diisocyanate. Isocyanurate of compound, isocyanurate of xylylene diisocyanate compound, isocyanurate of hydrogenated xylylene diisocyanate compound, adduct of tolylene diisocyanate compound, adduct of xylylene diisocyanate compound, adduct of hydrogenated xylylene diisocyanate compound It is preferable to contain at least one selected from the (C-1-2) second aromatic isocyanate compound group consisting of the body. It is preferable to use (C-1-1) the first aliphatic isocyanate compound group and (C-1-2) the second aromatic isocyanate compound group in combination. In the present invention, as the (C-1) trifunctional isocyanate compound, at least one selected from the (C-1-1) first aliphatic isocyanate compound group and (C-1-). 2) By using at least one selected from the second aromatic isocyanate compound group in combination, the balance of adhesive strength in the low-speed peeling region and the high-speed peeling region can be further improved. ..

Further, the (C-1) trifunctional isocyanate compound is at least one selected from the above-mentioned (C-1-1) first aliphatic isocyanate compound group, and the above-mentioned (C-1-). 2) Containing at least one selected from the second aromatic isocyanate compound group, 0.5 to 5.0 parts by weight in total with respect to 100 parts by weight of the acrylic polymer. It is preferably contained. In addition, at least one selected from the (C-1-1) first aliphatic isocyanate compound group and (C-1-2) second aromatic isocyanate compound group. The mixing ratio with at least one selected from the above is in the range of (C-1-1) :( C-1-2) in the range of 10%: 90% to 90%: 10% by weight. It is preferable to have.

Further, the (C-2) bifunctional isocyanate compound used in the present invention is preferably an acyclic aliphatic isocyanate compound, which is a compound produced by reacting a diisocyanate compound with a diol compound.
For example, a diisocyanate compound has a general formula "O = C = N-X-N = C = O" (where X is a divalent group), and a general formula "HO-Y-OH" (where Y is a divalent group). ), Examples of the compound produced by reacting the diisocyanate compound with the diol compound include the compound represented by the following general formula Z.

[General formula Z]
O = C = N-X- (NH-CO-O-YO-CO-NH-X) _n -N = C = O

Here, n is an integer of 0 or more. When n is 0, the general formula Z represents “O = C = N—X—N = C = O”. As the bifunctional acyclic aliphatic isocyanate compound, a compound having n of 0 in the general formula Z (a diisocyanate compound unreacted with a diol compound) may be contained, but a compound in which n is an integer of 1 or more is an essential component. It is preferable to include as. The bifunctional acyclic aliphatic isocyanate compound may be a mixture composed of a plurality of compounds having different n in the general formula Z.

The diisocyanate compound represented by the general formula “O = C = N—X—N = C = O” is an aliphatic diisocyanate. X is preferably an acyclic and aliphatic divalent group. The aliphatic diisocyanate is preferably one or more selected from the compound group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate.

The diol compound represented by the general formula "HO-Y-OH" is an aliphatic diol. Y is preferably an acyclic and aliphatic divalent group. Examples of the diol compound include 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, and 2-ethyl-2. -From the compound group consisting of butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol, and polypropylene glycol. It is preferably composed of one or more selected species.

The weight ratio (C-1 / C-2) of the (C-1) trifunctional isocyanate compound to the (C-2) bifunctional isocyanate compound is preferably 1 to 90. The amount of the (C) bifunctional or higher isocyanate compound is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer.

(D) The cross-linking accelerator may be a substance that functions as a catalyst for the reaction (cross-linking reaction) between the acrylic polymer and the cross-linking agent when the polyisocyanate compound is used as the cross-linking agent, and is a tertiary amine. Examples thereof include amine compounds such as, metal chelate compounds, organotin compounds, organolead compounds, and organometal compounds such as organozinc compounds. In the present invention, a metal chelate compound or an organic tin compound is preferable as the cross-linking accelerator.

The metal chelate compound is a compound in which one or more polydentate ligands L are bonded to the central metal atom M. The metal chelate compound may or may not have one or more monodentate ligands X attached to the metal atom M. For example, when the general formula of a metal chelate compound having one metal atom M is expressed by M (L) _m (X) _n , m ≧ 1 and n ≧ 0. When m is 2 or more, m L may be the same ligand or may be different ligands. When n is 2 or more, n Xs may be the same ligand or different ligands.

Examples of the metal atom M include Fe, Ni, Mn, Cr, V, Ti, Ru, Zn, Al, Zr, Sn and the like.
Examples of the polydentate ligand L include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetic acid, lauryl acetoacetic acid, and stearyl acetoacetic acid, and acetylacetone (also known as 2,4-pentandione). Examples thereof include β-diketones such as 2,4-hexanedione and benzoylacetone. These are keto-enol tautomeric compounds and may be enol-deprotonated enolates (eg, acetylacetonate) in the polydentate ligand L.
Examples of the monodentate ligand X include halogen atoms such as chlorine atom and bromine atom, pentanoyl group, hexanoyl group, 2-ethylhexanoyl group, octanoyl group, nonanoyl group, decanoyl group, dodecanoyl group and octadecanoyl group. Examples thereof include an alkoxy group such as a group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group and a butoxy group.

Specific examples of the metal chelate compound include tris (2,4-pentandionato) iron (III), iron tris acetylacetonate, titaniumtris acetylacetonate, ruthenium trisacetylacetonate, zinc bisacetylacetonate, and aluminum tris. Acetylacetonate, Zirconite Telux Acetylacetonate, Tris (2,4-hexanedionat) Iron (III), Bis (2,4-hexanezonato) Zinc, Tris (2,4-hexanezonato) Titanium, Tris Examples thereof include (2,4-hexanezonato) aluminum and tetrakis (2,4-hexanezonato) zirconium.

Examples of the organic tin compound include dialkyl tin oxide, a fatty acid salt of dialkyl tin, and a fatty acid salt of first tin. Conventionally, dibutyltin compounds have been widely used, but in recent years, the problem of toxicity of organotin compounds has been pointed out, and in particular, tributyltin (TBT) contained in dibutyltin compounds is also a concern as an endocrine disturbing substance. From the viewpoint of safety, a long-chain alkyl tin compound such as a dioctyl tin compound is preferable. Specific examples of the organic tin compound include dioctyl tin oxide and dioctyl tin dilaurate. Sn compounds can be used provisionally, but in the future, in view of the trend that the use of safer substances is required, Al, Ti, Fe, etc., which are safer than Sn, etc. It is preferable to use a metal chelate compound.
The crosslinking accelerator (D) in the pressure-sensitive adhesive composition according to the present invention is preferably at least one selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound.
The crosslinking accelerator (D) is preferably contained in an amount of 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the acrylic polymer.

(E) Ketoenol tetonic compounds include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetic acid, lauryl acetoacetic acid, and stearyl acetoacetic acid, acetylacetone, and 2,4-hexanedione. , Β-diketone such as benzoylacetone. In a pressure-sensitive adhesive composition using a polyisocyanate compound as a cross-linking agent, these prevent excessive increase in viscosity and gelation of the pressure-sensitive adhesive composition after blending the cross-linking agent by blocking the isocyanate group contained in the cross-linking agent. , The pot life of the adhesive composition can be extended.
The keto-enol tautomer compound is preferably contained in an amount of 0.1 to 300 parts by weight based on 100 parts by weight of the acrylic polymer.

Since the (E) keto-enol tautomer compound has an effect of suppressing cross-linking as opposed to the (D) cross-linking promoter, the ratio of the (E) keto-enol tautomer compound to the (D) cross-linking promoter. Is preferably set appropriately. In order to prolong the pot life of the pressure-sensitive adhesive composition and improve the storage stability, the weight ratio of (E) / (D) is preferably 70 to 1000, more preferably 70 to 700. , 80-600 is particularly preferable.

The acrylic polymer can optionally further contain (F) a polyalkylene glycol mono (meth) acrylic acid ester monomer as the copolymerizable monomer group. The (F) polyalkylene glycol mono (meth) acrylic acid ester monomer may be a compound in which one hydroxyl group is esterified as a (meth) acrylic acid ester among a plurality of hydroxyl groups of the polyalkylene glycol. Since the (meth) acrylic acid ester group becomes a polymerizable group, it can be copolymerized with the acrylic polymer. The other hydroxyl group may be OH as it is, or may be an alkyl ether such as methyl ether or ethyl ether, a saturated carboxylic acid ester such as an acetate ester, or the like.
Examples of the alkylene group contained in the polyalkylene glycol include, but are not limited to, an ethylene group, a propylene group, and a butylene group. The polyalkylene glycol may be a copolymer of two or more kinds of polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol. Examples of the polyalkylene glycol copolymer include polyethylene glycol-polypropylene glycol, polyethylene glycol-polybutylene glycol, polypropylene glycol-polybutylene glycol, polyethylene glycol-polypropylene glycol-polybutylene glycol, and the like. It may be a block copolymer or a random copolymer.
It is preferable that the polyalkylene glycol mono (meth) acrylic acid ester monomer (F) has an average number of repetitions of alkylene oxides constituting the polyalkylene glycol chain of 3 to 14. The "average number of repetitions of alkylene oxide" is the average number of repetitions of the alkylene oxide unit in the portion of the "polyalkylene glycol chain" contained in the molecular structure of the (F) polyalkylene glycol mono (meth) acrylic acid ester monomer. be.
In the (F) polyalkylene glycol mono (meth) acrylic acid ester monomer, the diester content in the monomer is preferably 0.2% or less. The “diester content in the monomer” is the content (% by weight) of the polyalkylene glycol di (meth) acrylic acid ester contained in the (F) polyalkylene glycol mono (meth) acrylic acid ester monomer.

The (F) polyalkylene glycol mono (meth) acrylic acid ester monomer was selected from polyalkylene glycol mono (meth) acrylate, methoxypolyalkylene glycol (meth) acrylate, and ethoxypolyalkylene glycol (meth) acrylate. It is preferably at least one kind.
More specifically, polyethylene glycol-mono (meth) acrylate, polypropylene glycol-mono (meth) acrylate, polybutylene glycol-mono (meth) acrylate, polyethylene glycol-polypropylene glycol-mono (meth) acrylate, polyethylene glycol-poly. Butylene glycol-mono (meth) acrylate, polypropylene glycol-polybutylene glycol-mono (meth) acrylate, polyethylene glycol-polypropylene glycol-polybutylene glycol-mono (meth) acrylate; methoxypolyethylene glycol- (meth) acrylate, methoxypolypropylene glycol -(Meta) acrylate, methoxypolybutylene glycol- (meth) acrylate, methoxy-polypropylene glycol-polypropylene glycol- (meth) acrylate, methoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, methoxy-polypropylene glycol-polybutylene Glycol- (meth) acrylate, methoxy-polypropylene glycol-polypropylene glycol-polybutylene glycol- (meth) acrylate; ethoxypolyethylene glycol- (meth) acrylate, ethoxypolypropylene glycol- (meth) acrylate, ethoxypolybutylene glycol- (meth) Acrylate, ethoxy-polypropylene glycol-polypropylene glycol- (meth) acrylate, ethoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, ethoxy-polypropylene glycol-polybutylene glycol- (meth) acrylate, ethoxy-polypropylene glycol-polypropylene glycol -Polybutylene glycol- (meth) acrylate and the like.
(A) When the total number of (meth) acrylic acid ester monomers having an alkyl group having C1 to C18 is 100 parts by weight, the weight of the (F) polyalkylene glycol mono (meth) acrylic acid ester monomer is 0 to 50 parts by weight. It is preferable that it is contained in a proportion of a portion. In the pressure-sensitive adhesive layer according to the present invention, the pressure-sensitive adhesive composition may not contain (F) a polyalkylene glycol mono (meth) acrylic acid ester monomer.

The pressure-sensitive adhesive composition can optionally contain a (H) polyether-modified siloxane compound having an HLB value of 7 to 15. The polyether-modified siloxane compound is a siloxane compound having a polyether group, and in addition to the usual siloxane unit [-SiR ¹ ₂ -O-], the siloxane unit having a polyether group [-SiR ¹ (R ² O (R 2 O)). It has R ³ O) _n R ⁴ ) -O-]. Here, R ¹ is one or more kinds of alkyl groups or aryl groups, R ² and R ³ are one or more kinds of alkylene groups, and R ⁴ is one or more kinds of alkyl groups or acyl groups. Etc. (terminal group). Examples of the polyether group include a polyoxyalkylene group such as a polyoxyethylene group [(C ₂ H ₄ O) _n ] and a polyoxypropylene group [(C ₃ H ₆ O) _n ].

The polyether-modified siloxane compound is preferably a polyether-modified siloxane compound having an HLB value of 7 to 15. Further, with respect to 100 parts by weight of the acrylic polymer, the amount of the polyether-modified siloxane compound having an HLB value of 7 to 15 is 1.0 part by weight or less (excluding the case of 0 parts by weight), 0.01 to 1.0. It is preferably contained in parts by weight. More preferably, it is 0.1 to 0.5 parts by weight.
The HLB is, for example, a hydrophilic lipophilic balance (hydrophilic lipophilic ratio) defined in JIS K3211 (surfactant term) and the like.

The polyether-modified siloxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group on a polyorganosiloxane backbone having a silicon hydride group by a hydrosilylation reaction. Specifically, dimethylsiloxane / methyl (polyoxyethylene) siloxane copolymer, dimethylsiloxane / methyl (polyoxyethylene) siloxane / methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane / methyl (polyoxypropylene) Examples thereof include siloxane polymers. The HLB value of the polyether-modified siloxane compound can be adjusted by selecting the ratio of the polyether group to the siloxane group.
By blending the (H) polyether-modified siloxane compound having an HLB value of 7 to 15 into the pressure-sensitive adhesive composition, the adhesive strength and contaminating property of the pressure-sensitive adhesive can be improved. If the pressure-sensitive adhesive composition does not contain a polyether-modified siloxane compound, the cost will be lower.

Further, as other components, the pressure-sensitive adhesive composition according to the present invention includes known known substances such as surfactants, curing accelerators, plasticizers, fillers, curing retarders, processing aids, antioxidants and antioxidants. Additives can be added as appropriate. These may be used alone or in combination of two or more.

The acrylic polymer used in the pressure-sensitive adhesive composition of the present invention has (a1) an alkyl group based on 100 parts by weight of a total of (meth) acrylic acid ester monomers having (A) alkyl groups having C1 to C18 carbon atoms. At least one kind of (meth) acrylic acid ester monomer having C1 to C4 carbon atoms is 1 to 30 parts by weight, and at least one kind of (meth) acrylic acid ester monomer having (a2) alkyl groups having C5 to C18 carbon atoms. Is synthesized by copolymerizing 70 to 99 parts by weight and 0.1 to 12 parts by weight of (B) at least one copolymerizable monomer containing a hydroxyl group as a copolymerizable monomer group. be able to. The copolymerizable monomer group may further contain (F) a polyalkylene glycol mono (meth) acrylic acid ester monomer. The polymerization method of the acrylic polymer is not particularly limited, and an appropriate polymerization method such as solution polymerization or emulsion polymerization can be used.
The pressure-sensitive adhesive composition of the present invention comprises (C) a bifunctional or higher functional isocyanate compound, (D) a cross-linking accelerator, (E) a ketoenol tautomer compound, and an optional additive as appropriate, in an acrylic polymer. Can be prepared by

Since the acrylic polymer does not contain a copolymerizable monomer containing a carboxyl group and a nitrogen-containing vinyl monomer not containing a hydroxyl group as a copolymerizable monomer group, the crosslinking rate is improved and the adhesive strength is stabilized. Is effective. As a monomer that reacts with (C) a bifunctional or higher functional isocyanate compound used as a cross-linking agent, it is preferable to use (B) a copolymerizable monomer containing a hydroxyl group. The preferable monomer composition of the acrylic polymer is one or more from the above (A) and the above (B), one or more from the above (A), the above (B) and the above (F), and the like. Can be mentioned.

The pressure-sensitive adhesive layer formed by cross-linking the pressure-sensitive adhesive composition has an adhesive force of 0.05 to 0.1 N / 25 mm at a low-speed peeling speed of 0.3 m / min and a high-speed peeling speed of 30 m / min. The adhesive strength is preferably 1.0 N / 25 mm or less. As a result, it is possible to obtain a performance in which the adhesive strength does not change much depending on the peeling speed, and it is possible to quickly peel even by high-speed peeling. Further, since it is reattached, even when the antistatic surface protective film is once peeled off, it does not require an excessive force and can be easily peeled off from the adherend.

It is preferable that the surface resistivity of the pressure-sensitive adhesive layer obtained by cross-linking the pressure-sensitive adhesive composition is 5.0 × 10 ⁺¹² Ω / □ or less, and the peeling band voltage is “± 0.6 kV or less”. In the present invention, "± 0.6 kV or less" means 0 to −0.6 kV and 0 to +0.6 kV, that is, −0.6 to +0.6 kV. If the surface resistivity is large, the performance of releasing static electricity generated by charging when the antistatic surface protective film is peeled off from the adherend is inferior. Therefore, by sufficiently reducing the surface resistivity, the peeling band voltage generated by the static electricity generated when the adherend peels off the adhesive layer is reduced, which affects the electric control circuit of the adherend and the like. Can be suppressed.

The gel fraction of the pressure-sensitive adhesive layer (the pressure-sensitive adhesive after cross-linking) obtained by cross-linking the pressure-sensitive adhesive composition of the present invention is preferably 95 to 100%. Due to such a high gel content, the adhesive strength does not become excessive at a low peeling speed, and the elution of unpolymerized monomers or oligomers from the acrylic polymer is reduced, resulting in contamination, high temperature, and high humidity. Durability is improved and contamination of the adherend can be suppressed.

The antistatic surface protective film of the present invention is formed by forming a pressure-sensitive adhesive layer formed by cross-linking a pressure-sensitive adhesive composition on one or both sides of a resin film. The antistatic surface protective film of the present invention is excellent in antistatic because a pressure-sensitive adhesive layer obtained by cross-linking a pressure-sensitive adhesive composition in which each of the above components (A) to (E) is blended in a well-balanced manner is formed. It has high performance, and has an excellent balance of adhesive strength in low-speed peeling speed and high-speed peeling speed, and also has excellent durability and stain resistance. Therefore, it can be suitably used as a surface protective film for a polarizing plate.

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, but is preferably, for example, about 5 to 40 μm, more preferably about 10 to 30 μm. From the adherend, the adhesive layer 2 having a slight adhesive strength having a peeling strength (adhesive strength) of the antistatic surface protective film on the surface of the adherend is about 0.03 to 0.3 N / 25 mm. It is preferable because it is excellent in operability when peeling off the antistatic surface protective film. Further, since the release film 5 is excellent in operability when the release film 5 is peeled off from the antistatic surface protective film 10, the release force of the release film 5 from the pressure-sensitive adhesive layer 2 is preferably 0.2 N / 50 mm or less.

Further, the release film 5 used for the antistatic surface protective film 10 according to the present invention has a resin composition containing a release agent containing dimethylpolysiloxane as a main component and an antistatic agent on one side of the resin film 3. The used release agent layer 4 is formed. The release agent layer 4 preferably further contains a silicone-based compound that is liquid at 20 ° C. The silicone-based compound in the release agent layer 4 is preferably a polyether-modified silicone.

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

Examples of the release agent containing dimethylpolysiloxane as a main component constituting the release agent layer 4 include known silicone-based release agents such as addition reaction type, condensation reaction type, cationic polymerization type, and radical polymerization type. Products commercially available as addition reaction type silicone release agents include, for example, KS-776A, KS-847T, KS-779H, KS-837, KS-778, KS-830 (manufactured by Shin-Etsu Chemical Co., Ltd.). , SRX-211, SRX-345, SRX-357, SD7333, SD7220, SD7223, LTC-300B, LTC-350G, LTC-310 (manufactured by Toray Dow Corning Co., Ltd.) and the like. Examples of products commercially available as a condensation reaction type include SRX-290 and SYLOFF-23 (manufactured by Toray Dow Corning Co., Ltd.). Products commercially available as cationically polymerized products include, for example, TPR-6501, TPR-6500, UV9300, VU9315, UV9430 (manufactured by Momentive Performance Materials), X62-7622 (manufactured by Shin-Etsu Chemical Co., Ltd.). ) And so on. Examples of products commercially available as a radical polymerization type include X62-7205 (manufactured by Shin-Etsu Chemical Co., Ltd.).

Examples of the silicone-based compound that is liquid at 20 ° C. constituting the release agent layer 4 include polyether-modified silicone, alkyl-modified silicone, and carbinol higher fatty acid ester-modified silicone. In the present invention, in order to improve the antistatic property on the surface of the pressure-sensitive adhesive layer, a silicone-based compound that is liquid at 20 ° C. in a state of being compatible with the release agent layer containing dimethylpolysiloxane as a main component is used. Be done. Among the modified silicone compounds, polyether-modified silicone is preferable for the application of the present invention. The polyether chain in the polyether-modified silicone is composed of ethylene oxide, propylene oxide, etc. For example, by selecting the molecular weight of the polyethylene oxide used for the side chain, physical properties such as compatibility with the silicone release agent and antistatic effect are obtained. Is adjusted.
Products commercially available as polyether-modified silicone include, for example, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-642 (manufactured by Shin-Etsu Chemical Co., Ltd.). SH8400, SH8700, SF8410 (manufactured by Toray Dow Corning Co., Ltd.), TSF-4440, TSF-4441, TSF-4445, TSF-4446, TSF-4450 (manufactured by Momentive Performance Materials), BYK-300, BYK -306, BYK-307, BYK-320, BYK-325, BYK-330 (manufactured by Big Chemie) and the like.
The amount of the silicone compound added, which is liquid at 20 ° C to the release agent containing dimethylpolysiloxane as the main component, varies depending on the type of the silicone compound and the degree of compatibility with the release agent, but an antistatic surface protective film is applied. It may be set in consideration of the desired peeling band voltage at the time of peeling from the body, the contaminating property to the adherend, the adhesive property, and the like.

The antistatic agent constituting the release agent layer 4 has good dispersibility in a release agent solution containing dimethylpolysiloxane as a main component and inhibits the curing of the release agent containing dimethylpolysiloxane as a main component. Those that do not are preferable. An alkali metal salt is suitable as such an antistatic agent.

Examples of the alkali metal salt include a metal salt composed of lithium, sodium and potassium. Specifically, for example, a cation consisting of Li ⁺ , Na ⁺ , K ⁺ , Cl ⁻ , Br ⁻ , I ⁻ , BF _4- , PF ₆ ⁻ , SCN ^{− ,} ClO _4- ^, CF ₃ SO _3- ^, A metal salt composed of anions consisting of (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 preferable. Used for. Among them, especially LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li (FSO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C and other lithium salts (Li salt), especially Li (CF ₃ SO ₂ ) ₂ N "abbreviation LiTFSI", Li (FSO ₂ ) ₂ N "abbreviation LiFSI" , LiCF ₃ SO ₃ "abbreviation LiTF or LiTf" is preferably used. These alkali metal salts may be used alone or in combination of two or more. A compound containing a polyoxyalkylene structure may be added to stabilize the ionic substance.
The amount of the antistatic agent added to the release agent containing dimethylpolysiloxane as the main component varies depending on the type of the antistatic agent and the degree of affinity with the release agent, but when the antistatic surface protective film is peeled off from the adherend. However, it may be set in consideration of the desired peeling band voltage, stain resistance to the adherend, adhesive properties, and the like.

The method of mixing the release agent containing dimethylpolysiloxane as a main component and the antistatic agent is not particularly limited. A method of adding an antistatic agent to a release agent containing dimethylpolysiloxane as a main component, mixing the mixture, and then adding and mixing a catalyst for curing the release agent. A release agent containing dimethylpolysiloxane as a main component is previously organic. A method of adding and mixing an antistatic agent and a catalyst for curing a release agent after diluting with a solvent. A release agent containing siloxane as a main component is diluted with an organic solvent in advance, then a catalyst is added and mixed, and then an antistatic agent is added. Any method may be used, such as a method of adding or mixing the above. Further, if necessary, an adhesion improver such as a silane coupling agent or a material that assists the antistatic effect such as a compound containing a polyoxyalkylene group may be added.
The method for mixing the polyether-modified silicone with the release agent is the same as the method for mixing with the antistatic agent, and is not particularly limited.

The mixing ratio of the release agent containing dimethylpolysiloxane as a main component and the antistatic agent is not particularly limited, but the antistatic agent is solidified with respect to the solid content 100 of the release agent containing dimethylpolysiloxane as a main component. A ratio of about 5 to 100 minutes is preferable. When the amount of the antistatic agent added in terms of solid content is less than the ratio of 5 to the solid content of 100 of the release agent containing dimethylpolysiloxane as a main component, the amount of transfer of the antistatic agent to the surface of the pressure-sensitive adhesive layer also increases. The amount is reduced, and it becomes difficult for the adhesive to exert its antistatic function. Further, when the amount of the antistatic agent added in terms of solid content exceeds 100 with respect to the solid content of 100 of the release agent containing dimethylpolysiloxane as the main component, dimethylpolysiloxane is used as the main component together with the antistatic agent. The release agent is also transferred to the surface of the pressure-sensitive adhesive layer, which may reduce the pressure-sensitive adhesive properties of the pressure-sensitive adhesive.
The mixing ratio of the polyether-modified silicone with respect to the release agent is preferably about the same as the mixing ratio of the antistatic agent, and is not particularly limited.

The method of forming the pressure-sensitive adhesive layer 2 and the method of attaching the release film 5 to the base film 1 of the antistatic surface protective film 10 according to the present invention may be performed by a known method and is not particularly limited. Specifically, (1) a method in which a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer 2 is applied to one side of a base film 1, dried to form a pressure-sensitive adhesive layer, and then a release film 5 is bonded. (2) A method of applying and drying a pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 2 on the surface of the release film 5 to form the pressure-sensitive adhesive layer, and then laminating the base film 1 and the like can be mentioned. However, any method may be used.

Further, 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, Mayer bar coating, and air knife coating can be used.

Similarly, the release 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.

FIG. 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.
By peeling the release film 5 from the antistatic surface protective film 10 shown in FIG. 1, a part of the antistatic agent (reference numeral 7) contained in the release agent layer 4 of the release film 5 is removed from the antistatic surface protective film. It is transferred (adhered) to the surface of the pressure-sensitive adhesive layer 2 of 10. Therefore, in FIG. 2, the antistatic agent transferred to the surface of the pressure-sensitive adhesive layer 2 of the antistatic surface protective film is schematically shown by the spots of reference numeral 7.
In the antistatic surface protective film according to the present invention, the antistatic surface protective film 11 in the state where the release film shown in FIG. 2 is peeled off is transferred to the surface of the pressure-sensitive adhesive layer 2 when the antistatic surface protective film 11 is attached to the adherend. In addition, the antistatic agent comes into contact with the surface of the adherend. As a result, when the antistatic surface protective film is peeled off from the adherend again, the peeling band voltage can be suppressed to a low level.

FIG. 3 is a cross-sectional view showing an embodiment of the optical component of the present invention.
The release film 5 is peeled off from the antistatic surface protective film 10 of the present invention, and the pressure-sensitive adhesive layer 2 is exposed and bonded to the optical component 8 which is an adherend via the pressure-sensitive adhesive layer 2. To.
That is, FIG. 3 shows an optical component 20 to which the antistatic surface protective film 10 of the present invention is attached. Examples of the optical component include an optical film 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 optical components are used as constituent members of various display devices such as liquid crystal display panels and organic EL display panels, and various instruments such as optical system devices. Further, examples of the optical component include an optical film such as an antireflection film, a hard coat film, and a transparent conductive film for a touch panel. In particular, the surface of an optical film such as a low-reflection treated polarizing plate (LR polarizing plate) or an anti-glare low-reflection treated polarizing plate (AG-LR polarizing plate) whose surface is antifouling treated with a silicone compound or a fluorine compound is used to prevent stains. It can be suitably used as an antistatic surface protective film to be bonded to a contaminated surface.
Examples of the low-reflection surface treatment layer of the LR polarizing plate include a metal oxide thin film (a vapor-deposited film such as SiO ₂ and TiO ₂ ) and an antireflection film such as a fluororesin. The antistatic surface protective film of the present invention reduces the peeling band voltage and has low stain resistance to the adherend even when the adhesive layer of the antistatic surface protective film is in contact with and bonded to these antireflection films. Can be compatible with.
According to the optical component of the present invention, when the antistatic surface protective film 10 is peeled off and removed from the optical component (optical film) which is an adherend, the peeling band voltage can be suppressed to a sufficiently low level, so that the driver can be used. There is no risk of damaging circuit components such as ICs, TFT elements, and gate wire drive circuits, and it is possible to improve production efficiency in the process of manufacturing liquid crystal display panels, organic EL display panels, etc., and maintain the reliability of the production process. ..

Next, the present invention will be further described by way of examples.

<Manufacturing of adhesive composition>
[Example 1]
Nitrogen gas was introduced into a reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen introduction tube, and the air in the reactor was replaced with nitrogen gas. Then, 60 parts by weight of a solvent (ethyl acetate) was added to the reaction apparatus together with 10 parts by weight of methyl acrylate, 90 parts by weight of 2-ethylhexyl acrylate, 5.0 parts by weight of 8-hydroxyoctyl acrylate, and 10 parts by weight of polypropylene glycol monoacrylate (n = 12). Added parts by weight. Then, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours and reacted at 65 ° C. for 6 hours to obtain an acrylic polymer solution of Example 1 having a weight average molecular weight of 500,000. rice field. To this acrylic polymer solution, 8.5 parts by weight of acetylacetone was added and stirred, and then 2.0 parts by weight of Coronate HX (isocyanurate form of hexamethylene diisocyanate compound) and 0.1 parts by weight of titanium trisacetylacetonate were added. Was stirred and mixed to obtain the pressure-sensitive adhesive composition of Example 1.

[Examples 2 to 6 and Comparative Examples 1 to 3]
The composition of the pressure-sensitive adhesive composition of Example 1 is the same as that of Example 1 except that the composition of the pressure-sensitive adhesive composition is as shown in Tables 1 and 2, respectively, and the pressure-sensitive adhesive compositions of Examples 2 to 6 and Comparative Examples 1 to 3 are used. I got something. In Tables 1 and 2, the monomers contained (copolymerized) in the acrylic polymer are (A), (B), (F), and "carboxyl group-containing monomer".

Tables 1 and 2 divide the integrated table showing the compounding ratio of each component into two, and in each case, the numerical value of the weight part obtained by assuming that the total of the group (A) is 100 parts by weight is enclosed in parentheses. Indicated by. The compound names of the abbreviations of the respective components used in Tables 1 and 2 are shown in Tables 3 and 4. Coronate (registered trademark) HX, HL and L are trade names of Tosoh Corporation, and Takenate (registered trademark) D-140N, D-127N and D-110N are trade names of Mitsui Chemicals, Inc. .. In "Antistatic Agents" in Table 2 and Table 7 below, LiTFSI stands for Li (CF ₃ SO ₂ ) ₂ N, LiFSI stands for Li (FSO ₂ ) ₂ N, and LiTF stands for LiCF ₃ SO ₃ . Further, in the compound used for the (F) polyalkylene glycol mono (meth) acrylic acid ester monomer of each example, the diester content in the monomer is 0.2% or less.

<Synthesis of bifunctional isocyanate compound>
The bifunctional isocyanate compounds of Synthesis Examples 1 and 2 were synthesized by the following methods. As shown in Tables 5 and 6, the diisocyanate and the diol compound were mixed at a molar ratio of NCO / OH = 16 and reacted at 120 ° C. for 3 hours, and then under reduced pressure using a thin film evaporator. The unreacted diisocyanate was removed to obtain the desired bifunctional isocyanate compound.

<Manufacturing of antistatic surface protective film>
[Example 1]
Additive reaction type silicone (manufactured by Toh Redow Corning Co., Ltd., product name: SRX-345) 5 parts by weight, polyether-modified silicone (manufactured by Toh Redow Corning Co., Ltd., product name: SH8400, main component: dimethyl, methyl (polyethylene oxide) Acetate) siloxane) 0.15 parts by weight, Li (CF ₃ SO ₂ ) ₂ N 0.5 parts by weight, 95 parts by weight of 1: 1 mixed solvent of toluene and ethyl acetate, and platinum catalyst (Dow Corning Co., Ltd.) (Manufactured by, product name: SRX-212 catalystist) 0.05 parts by weight were mixed, stirred and mixed to prepare a coating material forming the release agent layer of Example 1. The paint forming the release agent layer of Example 1 is 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 becomes 0.2 μm, and a hot air circulation oven at 120 ° C. Was dried for 1 minute to obtain a release film of Example 1.
The pressure-sensitive adhesive composition of Example 1 was applied to the surface of a polyethylene terephthalate film having a thickness of 38 μm so as to have a thickness of 20 μm after drying, and then dried in a hot air circulation oven at 100 ° C. for 2 minutes. Formed a pressure-sensitive adhesive layer. Then, the release agent layer (silicone-treated surface) of the release film of Example 1 prepared above was bonded to the surface of this pressure-sensitive adhesive layer. The obtained pressure-sensitive adhesive film was kept warm in an environment of 40 ° C. for 5 days to cure the pressure-sensitive adhesive to obtain an antistatic surface protective film of Example 1.

[Example 2]
The same as in Example 1 except that the pressure-sensitive adhesive composition of Example 1 was changed to the pressure-sensitive adhesive composition of Example 2 and the antistatic agent used for the release agent layer was LiCF ₃ SO ₃ . Antistatic surface protective film was obtained.

[Examples 3 to 6]
Same as Example 1 except that the pressure _- sensitive adhesive composition of Example 1 was used as the pressure-sensitive adhesive composition of Examples 3 to 6 and the antistatic agent used for the release agent layer was Li (FSO ₂ ) 2N. The antistatic surface protective film of Examples 3 to 6 was obtained.

[Comparative Example 1]
Additive reaction type silicone (manufactured by Toray Dow Corning Co., Ltd., product name: SRX-345) by 5 parts by weight, 95 parts by weight of a 1: 1 mixed solvent of toluene and ethyl acetate, and platinum catalyst (manufactured by Toray Dow Corning Co., Ltd.) , Product name: SRX-212 catalyst) 0.05 parts by weight were mixed, stirred and mixed to prepare a coating material forming the release agent layer of Comparative Example 1. The paint forming the release agent layer of Comparative Example 1 is 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 becomes 0.2 μm, and a hot air circulation oven at 120 ° C. Was dried for 1 minute to obtain a release film of Comparative Example 1.
The pressure-sensitive adhesive composition of Comparative Example 1 was applied to the surface of a polyethylene terephthalate film having a thickness of 38 μm so as to have a thickness of 20 μm after drying, and then dried in a hot air circulation oven at 100 ° C. for 2 minutes. Formed a pressure-sensitive adhesive layer. Then, the release agent layer (silicone-treated surface) of the release film of Comparative Example 1 prepared above was bonded to the surface of this pressure-sensitive adhesive layer. The obtained adhesive film was kept warm in an environment of 40 ° C. for 5 days to cure the adhesive to obtain an antistatic surface protective film of Comparative Example 1.

[Comparative Example 2]
An antistatic surface protective film of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that the pressure-sensitive adhesive composition of Comparative Example 1 was changed to the pressure-sensitive adhesive composition of Comparative Example 2.

[Comparative Example 3]
The same as in Example 1 except that the pressure _- sensitive adhesive composition of Example 1 was changed to the pressure-sensitive adhesive composition of Comparative Example 3 and the antistatic agent used for the release agent layer was Li (FSO ₂ ) 2N. An antistatic surface protective film of Comparative Example 3 was obtained.

Table 7 shows the composition of the release agent layer in the antistatic surface protective films of Examples 1 to 6 and Comparative Examples 1 to 3.

<Test method and evaluation>
The antistatic surface protective films of Examples 1 to 6 and Comparative Examples 1 to 3 were aged at 23 ° C. and 50% RH for 7 days, and then the release film (silicone resin coated PET film) was peeled off. The one with the pressure-sensitive adhesive layer exposed was used as a sample for measuring the surface resistance.
Further, the antistatic surface protective film on which the pressure-sensitive adhesive layer is exposed is attached to the surface of the polarizing plate attached to the liquid crystal cell via the pressure-sensitive adhesive layer, and after being left for one day, the temperature is 50 ° C. and 5 atm. A sample that was autoclaved for 20 minutes and left at room temperature for another 12 hours was used as a measurement sample for adhesive strength, peeling band voltage, and contamination.

<Adhesive strength>
The measurement sample obtained above (a 25 mm wide antistatic surface protective film bonded to the surface of the polarizing plate) was peeled at a low speed (0.3 m / min) in the 180 ° direction using a tensile tester. And peeling was performed at a high peeling speed (30 m / min), and the measured peeling strength was taken as the adhesive strength.

<Surface resistivity>
After aging, before bonding to the polarizing plate, the release film (PET film coated with silicone resin) is peeled off to expose the adhesive layer, and the resistance meter Hiresta UP-HT450 (manufactured by Mitsubishi Chemical Analytec) is used. The surface resistance of the pressure-sensitive adhesive layer was measured.

<Peeling band voltage>
High-precision electrostatic sensors SK-035 and SK-200 (stocks) can be used to measure the voltage (band voltage) generated by charging the polarizing plate when the measurement sample obtained above is peeled 180 ° at a tensile speed of 30 m / min. It was measured using (manufactured by the company Keyence), and the maximum value of the measured value was taken as the peeling band voltage.

<Pollutivity>
A polarizing plate with a low-reflection surface treatment applied to one side of the glass plate is placed through a pressure-sensitive adhesive layer (for example, a double-sided pressure-sensitive adhesive tape different from the pressure-sensitive adhesive layer of the antistatic surface protective film) using a laminating machine. And stick them together. Then, the antistatic surface protective film is bonded to the surface of the polarizing plate using a bonding machine. After storage in an environment of 23 ° C. and 50% RH for a period of 3 days and 30 days, the antistatic surface protective film is peeled off, and the state of contamination on the surface of the polarizing plate is visually observed.
The surface contamination is "○" when the surface of the polarizing plate is not contaminated in both 3-day storage and 30-day storage, and when there is slight contamination in either 3-day storage or 30-day storage. Was evaluated as “△”, and the case of contamination was evaluated as “×”.

Table 8 shows the evaluation results. The surface resistivity is expressed by a method in which "m × 10 ^{+ n} " is set to "mE + n" (where m is an arbitrary real number and n is a positive integer).

From the measurement results shown in Table 8, the following can be seen.
The antistatic surface protective films of Examples 1 to 6 according to the present invention have appropriate adhesive strength, do not contaminate the surface of the adherend, and when the antistatic surface protective film is peeled off from the adherend. The peeling band voltage is low.
On the other hand, the antistatic surface protective film of Comparative Example 1 in which the antistatic agent was added to the pressure-sensitive adhesive layer had a low surface resistivity of the pressure-sensitive adhesive layer and was good, but the contamination property was slightly inferior.
Further, in the antistatic surface protective film of Comparative Example 2, in addition to adding an antistatic agent to the pressure-sensitive adhesive layer, (a1) a (meth) acrylic acid ester monomer having an alkyl group having C1 to C4 carbon atoms and a (meth) acrylic acid ester monomer, and (B) Probably because the amount of the copolymerizable monomer containing a hydroxyl group added was large, the adhesive strength was large, the peeling zone voltage was high, and the contaminantability was slightly inferior.
Further, in the antistatic surface protective film of Comparative Example 3, the acrylic polymer does not contain the (a1) (meth) acrylic acid ester monomer having an alkyl group having C1 to C4 carbon atoms, but contains a monomer containing a carboxyl group. Therefore, the adhesive strength was high and the contaminantability was inferior.
That is, in Comparative Examples 1 and 2 in which the antistatic agent is mixed with the pressure-sensitive adhesive layer, it is difficult to achieve both reduction of the peeling zone voltage and low contamination with the adherend. On the other hand, in Examples 1 to 6, in which the antistatic agent was added to the release agent layer and then the antistatic agent contained in the release agent layer was transferred to the surface of the pressure-sensitive adhesive layer, a small amount of antistatic agent was applied to the release agent layer. Since the effect of reducing the peeling zone voltage was obtained even when the agent was added, there was no contamination on the adherend, and a good antistatic surface protective film was obtained.

The antistatic surface protective film of the present invention is, for example, an optical film such as a polarizing plate, a retardation plate, a lens film for a display, and the surface of the optical component in a production process of various optical components. Can be used to protect. In particular, when it is used as an antistatic surface protective film for an optical film such as an LR polarizing plate or an AG-LR polarizing plate whose surface is antifouling treated with a silicone compound or a fluorine compound, it is peeled off from the adherend. At that time, the amount of static electricity generated can be reduced.
The antistatic surface protective film of the present invention has less contamination on the adherend and has excellent peeling antistatic performance without deterioration over time, thus improving the yield of the production process of the optical film, optical parts, and the like. It can be used and has great industrial utility value.

1 ... Base film, 2 ... Adhesive layer, 3 ... Resin film, 4 ... Release agent layer, 5 ... Release film, 7 ... Antistatic agent, 8 ... Adhesive (optical component), 10 ... Antistatic surface protection Film, 11 ... Antistatic surface protective film from which the release film has been peeled off, 20 ... Optical components to which an antistatic surface protective film has been bonded.

Claims (3)

A pressure-sensitive adhesive layer obtained by cross-linking a pressure-sensitive adhesive composition containing an acrylic polymer and a cross-linking agent is formed on one side of a base material made of a transparent resin, and a resin is formed on the surface of the pressure-sensitive adhesive layer. A release film in which a release agent layer containing an antistatic agent is laminated on one side of the film is an antistatic surface protection film formed by laminating the release agent layer via the release agent layer.
The acrylic polymer is
(A) A total of 100 parts by weight of the (meth) acrylic acid ester monomer having an alkyl group having C1 to C18 carbon atoms.
(B) The acrylic polymer is a copolymer obtained by copolymerizing at least one copolymerizable monomer containing a hydroxyl group with 0.1 to 12 parts by weight.
Of the total 100 parts by weight of the (meth) acrylic acid ester monomer having C1 to C18 carbon atoms in the (A) alkyl group.
(A1) At least one kind of (meth) acrylic acid ester monomer having an alkyl group having C1 to C4 carbon atoms is added to 1 to 30 parts by weight.
(A2) The alkyl group contains at least one of the (meth) acrylic acid ester monomers having C5 to C18 carbon atoms in a proportion of 70 to 99 parts by weight.
The acrylic polymer does not copolymerize a copolymerizable monomer containing a carboxyl group and a nitrogen-containing vinyl monomer containing no hydroxyl group.
At least one selected from the compound group consisting of methyl (meth) acrylate and ethyl (meth) acrylate among at least one of the (meth) acrylic acid ester monomers having the number of carbon atoms of the (a1) alkyl group of C1 to C4. Contains seeds
The pressure-sensitive adhesive composition further contains (C) a bifunctional or higher functional isocyanate compound, (D) a cross-linking accelerator, and (E) a keto-enol tautomer compound, and also contains an antistatic agent. Not done,
An antistatic surface protective film having a surface resistivity of 5.0 × 10 ⁺¹² Ω / □ or less and a peeling band voltage of ± 0.6 kV or less of the pressure-sensitive adhesive layer. An optical film to which the antistatic surface protective film according to claim 1 is bonded. An optical component to which the antistatic surface protective film according to claim 1 is bonded.

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