KR20210000663A - Method for producing antistatic surface-protective film, and antistatic surface-protective film - Google Patents

Abstract

Provided is an antistatic surface protective film which has a well-balanced adhesive force at a low peeling speed and a high peeling speed and can achieve compatibility of antistatic performance and stain resistance. A release film (5) on which a release agent layer (4) containing an antistatic agent is laminated is bonded to a surface of an adhesive layer (2) formed by crosslinking an adhesive composition via the release agent layer (4), and the antistatic agent of the release agent layer (4) is transferred to the surface of the adhesive layer (2). The adhesive composition comprises: (A) an acrylic polymer containing 50 parts by weight or more of 2-ethylhexyl acrylate and 5 to 40 parts by weight of a total of one or more monofunctional methacrylate monomers whose homopolymer has a Tg that is 0°C or higher based on 100 parts by weight of a total of at least two kinds of alkyl (meth) acrylates having C1 to C10 carbon atoms; (C) an isocyanate compound having a trifunctionality or higher; (D) a crosslinking retarder; and (E) a crosslinking accelerator other than a tin compound.

Description

Manufacturing method of antistatic surface protective film, antistatic surface protective film TECHNICAL FIELD [METHOD FOR PRODUCING ANTISTATIC SURFACE-PROTECTIVE FILM, AND ANTISTATIC SURFACE-PROTECTIVE FILM}

The present invention relates to a method for producing an antistatic surface protective film, which can be preferably used for a surface protective film such as a surface protective film for a polarizing plate, and an antistatic surface protective film. More specifically, a method of manufacturing an antistatic surface protective film capable of achieving both antistatic performance and stain resistance performance, as well as having a balanced adhesive force in a low-speed peeling rate and a high-speed peeling rate, and antistatic surface protection It's about providing a film.

Conventionally, in a manufacturing process of an optical member such as a polarizing plate, which is a member constituting a liquid crystal display, a surface protective film for temporarily protecting the surface of the optical member is bonded. Such a surface protection film is used only in the process of manufacturing an optical member, and is removed by peeling from the optical member when the optical member is attached to a liquid crystal display. Since the surface protective film for protecting the surface of such an optical member is used only in the manufacturing process of the optical member, it is also generally referred to as a process film.

As described above, in the surface protective film used in the process of manufacturing an optical member, an adhesive layer is formed on one side of a polyethylene terephthalate (PET) resin film having optical transparency. In addition, in order to protect the pressure-sensitive adhesive layer on the surface of the pressure-sensitive adhesive layer of the surface protection film, a release-treated release film is adhered to the surface of the pressure-sensitive adhesive layer.

Further, optical members such as polarizing plates are subjected to a product inspection accompanying optical evaluation such as display capability, color, contrast, and foreign matter mixing of the liquid crystal panel in a state in which the surface protective film is adhered thereto. For this reason, the required performance for the surface protection film is that no air bubbles or foreign substances are mixed in the pressure-sensitive adhesive layer, and that the adhesion of the low molecular weight component of the pressure-sensitive adhesive composition to the surface of the adherend can be reduced, that is, contamination resistance. It is required to have performance.

In addition, when peeling the surface protective film from an optical member such as a polarizing plate, there is a concern that the peeling charge caused by static electricity generated when the pressure-sensitive adhesive layer is peeled from the adherend affects the failure of the electric control circuit of the liquid crystal display. do. For this reason, the pressure-sensitive adhesive layer of the surface protective film is required to have excellent antistatic performance.

In addition, in addition to triacetyl cellulose (TAC), which is conventionally used as a protective layer (also called a protective film) of a polarizer of a polarizing plate, acrylic resins such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), etc. When peeling the surface protective film of a polarizing plate, such as a polyester resin, a cyclic olefin polymer, and a polycarbonate, the adoption of the material which is easy to cause peeling charge is expanding. For this reason, it is necessary that the antistatic performance required for the pressure-sensitive adhesive layer for a surface protective film of the polarizing plate is superior to the conventional one.

Moreover, when finally peeling a surface protective film from an optical member, such as a polarizing plate, it is required to be able to peel quickly. So-called high-speed peeling, so as to be able to peel quickly, the adhesive force is required to have little change even with the peeling speed.

As described above, in recent years, with respect to the pressure-sensitive adhesive layer constituting the surface protection film, (1) balancing the adhesive strength in the low-speed peeling speed and the high-speed peeling speed, (2) having fouling resistance, (3) excellent charging What has prevention performance, etc. are demanded from the point of ease of use in using a surface protective film.

However, with respect to the required performance for the pressure-sensitive adhesive layer constituting the surface protective film, although it is possible to satisfy the respective required performance of each of these (1) to (3), (1) required for the pressure-sensitive adhesive layer of the surface protective film It was a very difficult task to simultaneously satisfy all the required performances of) to (3).

In order to solve these problems, for example, (1) having a balance of adhesive strength in a low-speed peeling speed and a high-speed peeling speed, (2) having a stain resistance performance, and (3) having excellent antistatic performance As for each, the following proposals are known.

(1) Regarding the balance of adhesive force in the low-speed peeling rate and the high-speed peeling rate, a copolymer of a (meth)acrylate alkyl ester having an alkyl group having 7 or less carbon atoms and a copolymerizable compound containing a carboxyl group is used as a main component, and this is a crosslinking agent. In the acrylic pressure-sensitive adhesive layer obtained by cross-linking treatment, there is a problem that adhesion of the pressure-sensitive adhesive to the adherend side occurs when adhered for a long period of time, and the increase in the adhesive force to the adherend with time is large. In order to avoid this, a copolymer of a (meth)acrylate alkyl ester having an alkyl group having 8 to 10 carbon atoms and a copolymerizable compound having an alcoholic hydroxyl group is used, and the gel fraction obtained by crosslinking this with a crosslinking agent is 60% or more, and A surface protection member in which the pressure-sensitive adhesive layer is formed is known (Patent Document 1).

However, in the pressure-sensitive adhesive layer described in Patent Document 1, there has been a problem that the increase in the adhesive force to the adherend with time change has not been completely solved.

Further, it is known that a small amount of a copolymer of an alkyl (meth)acrylate and a copolymerizable compound containing a carboxyl group is blended in the same copolymer as described above to form a pressure-sensitive adhesive layer obtained by crosslinking the same with a crosslinking agent. However, when these pressure-sensitive adhesive layers have low surface tension and are used to protect the surface of a plastic plate with a smooth surface, it may cause peeling phenomena such as lifting due to heating during processing or storage, or at high speed peeling speed, which is a manual area. There was also a problem that the re-peelability was poor due to the high adhesion of

In order to solve these problems, a) 100 parts by weight of an alkyl (meth)acrylate containing an alkyl (meth)acrylate having an alkyl group having 8 to 10 carbon atoms as a main component, b) 1 to 15 parts by weight of a copolymerizable compound containing a carboxyl group A pressure-sensitive adhesive composition comprising a copolymer of a monomer mixture obtained by adding parts and c) 3 to 100 parts by weight of a vinyl ester of an aliphatic carboxylic acid having 1 to 5 carbon atoms, and a crosslinking agent equivalent to or more than the carboxyl group of the component b). It has been proposed (Patent Document 2).

In the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition described in Patent Document 2, during processing or storage, peeling phenomena such as lifting do not occur, and the increase in adhesive strength over time is small, and re-peelability is excellent, and long-term storage, In particular, even long-term storage in a high-temperature atmosphere, it is said that it can be peeled again with a small force, and the adhesive residue is not generated on the adherend at that time, and even when high-speed peeling is performed, it can be peeled again with a small force.

However, in the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition described in Patent Document 2, the gel fractions of the pressure-sensitive adhesive layers in Examples 1 to 3 are all 90%, and the adhesive strength at a low-speed peeling rate tends to be excessive, and from the pressure-sensitive adhesive layer Unpolymerized monomers or oligomers are easily eluted. In addition, in Patent Document 2, there is no description of antistatic performance and fouling resistance, and when a material that is liable to cause peeling and charging is used as an adherend, it is improved to a pressure-sensitive adhesive layer having excellent antistatic performance and fouling resistance. There was a problem that it was difficult.

In addition, (2) for those having stain resistance, 0 parts by mass or more and less than 0.5 parts by mass of carboxyl group-containing monomer, 0.6 to 9 parts by mass of hydroxy group-containing (meth)acrylic monomer, and 99.4 to 90.5 parts by mass of (meth)acrylic acid ester monomer 100 parts by mass of a (meth)acrylic copolymer having a weight average molecular weight of 100,000 or more and less than 1 million; And a pressure-sensitive adhesive composition containing 0.1 to 5 parts by mass of a carbodiimide crosslinking agent (Patent Document 3).

The pressure-sensitive adhesive composition described in Patent Document 3 is characterized by using a carbodiimide-based cross-linking agent as a cross-linking agent for a (meth)acrylic copolymer having a specific composition. Thereby, it is possible to provide a pressure-sensitive adhesive layer having a crosslinked structure capable of following shrinkage due to pressure and temperature during autoclave treatment. For this reason, the pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition described in Patent Document 3 can suppress and prevent foaming even under high temperature and high pressure conditions (in the case of autoclave treatment), has excellent fouling resistance, and excellent transparency. It is said to be.

However, in the pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition described in Patent Document 3, the stain resistance is improved, but the antistatic performance is improved along with the excellent adhesion performance by balancing the adhesive force in the low-speed peeling speed and the high-speed peeling speed. Reconciliation has not been realized, and it remains an additional task to be solved.

In addition, (3), as a method for imparting antistatic properties to the surface protective film, as a method for imparting antistatic properties to the surface protective film, a method of incorporating an antistatic agent into a base film is known. Examples of antistatic agents include (a) various cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium salts, and primary to tertiary amino groups, (b) sulfonate groups, sulfate ester bases, and phosphoric acid esters. Anionic antistatic agents having anionic groups such as bases and phosphonic acid groups, (c) amphoteric antistatic agents such as amino acid and amino sulfuric acid esters, (d) nonionic charging such as amino alcohol, glycerin and polyethylene glycol An inhibitor, (e) a high molecular weight antistatic agent obtained by making the above antistatic agent high molecular weight, etc. are disclosed (Patent Document 4).

However, in the surface protective film described in Patent Document 4, there is a description of imparting antistatic performance related to adhesion of foreign matter to an adherend, but a solution for achieving both excellent adhesion performance and stain resistance performance is not described. However, it remains an additional task to be solved.

In addition, in recent years, it has been proposed to contain an antistatic agent in a base film or to directly contain an antistatic agent in the pressure-sensitive adhesive layer without being applied to the surface of the base film. For example, an antistatic pressure-sensitive adhesive composition is disclosed wherein a salt having an anion having a fluoro group and a sulfonyl group is dissolved in a polyether ester plasticizer containing a polyether group in the main chain. (Patent Document 5).

In the pressure-sensitive adhesive composition described in Patent Document 5, an ester formed from a mono or dicarboxylic acid having a saturated or unsaturated acyclic hydrocarbon group as a plasticizer and an alcohol having an acyclic hydrocarbon group having 1 to 20 carbon atoms, or in the unsaturated acyclic hydrocarbon group It is disclosed to use plasticizers in which the unsaturated groups are epoxidized esters. The mono or dicarboxylic acid having such a saturated or unsaturated acyclic hydrocarbon group has a carbon number close to that of the acrylic monomer constituting the acrylic copolymer used in the pressure-sensitive adhesive layer, so that compatibility with the antistatic pressure-sensitive adhesive composition becomes good, and the plasticizer Is preferably held in the acrylic antistatic pressure-sensitive adhesive composition, so that bleed-out is suppressed.

However, in the pressure-sensitive adhesive layer obtained by crosslinking the antistatic pressure-sensitive adhesive composition described in Patent Literature 5, there is a disclosure of a technique for improving antistatic performance and bleed-out, but it is excellent by balancing the adhesive force in a low-speed peeling speed and a high-speed peeling speed. There is no description of what the adhesive performance is obtained from, and the subject of obtaining an adhesive layer having excellent adhesive performance remains.

Japanese Laid-Open Patent Publication No. 63-225677 Japanese Laid-Open Patent Publication No. Hei 11-256111 Japanese Unexamined Patent Publication No. 2011-122054 Japanese Laid-Open Patent Publication No. Hei 11-070629 Japanese Unexamined Patent Publication No. 2014-118469

As described above, as the required performance for the pressure-sensitive adhesive layer constituting the surface protective film, (1) balancing the adhesive force in the low-speed peeling speed and the high-speed peeling speed, (2) having fouling resistance, (3) No prior art has been found to solve the problem of simultaneously achieving what has excellent antistatic performance.

In addition, the relationship between the antistatic performance of the pressure-sensitive adhesive layer and the surface protective film using the pressure-sensitive adhesive composition conventionally formed using the pressure-sensitive adhesive composition with antistatic performance and the stain resistance for the adherend is a trade-off relationship, and the antistatic performance It was difficult to improve the fouling resistance performance while maintaining.

Furthermore, in recent years, the kinds of materials of the adherend to which the surface protection film is adhered are increasing, and the surface-treated state of the adherend also spans many areas, so that the pressure-sensitive adhesive layer constituting the surface protection film is particularly suitable for all adherends, It is becoming increasingly difficult to balance the adhesive strength in the above (1) low-speed peeling speed and high-speed peeling speed, and (2) having stain resistance performance.

The present invention has been made in view of the above circumstances, and has a balanced adhesive force in a low-speed peeling speed and a high-speed peeling speed, and the manufacture of an antistatic surface protective film capable of achieving both antistatic performance and stain resistance performance It is a subject to provide a method and an antistatic surface protection film.

In order to solve the above problems, the antistatic surface protective film of the present invention includes (A) 2-ethylhexyl acrylate in the alkyl (meth)acrylate having C1 to C10 carbon atoms in the alkyl group, and the glass transition point temperature of the homopolymer. The content ratio of the monofunctional methacrylate monomer having (Tg) of 0°C or higher is specified in a specific range. In addition, after coating and drying the pressure-sensitive adhesive composition to laminate the pressure-sensitive adhesive layer, a liquid silicone-based compound and an antistatic agent are added to the surface of the pressure-sensitive adhesive layer in an appropriate amount at 20°C to reduce contamination of the adherend ( It has a fouling performance), and it is made into a technical idea to suppress the peeling electrification voltage at the time of peeling from an optical film as an adherend low.

In order to solve the above problems, the present invention is a method of manufacturing an antistatic surface protective film, the following steps (1) to (3),

Step (1): A pressure-sensitive adhesive composition containing an acrylic polymer and a crosslinking agent, wherein the acrylic polymer comprises: (A) 100 parts by weight in total of at least two kinds of alkyl (meth)acrylates having C1-C10 alkyl groups, (B) 1.0 to 6.0 parts by weight in total of at least one copolymerizable monomer containing a hydroxyl group, and (F) at least one of the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomers constituting the polyalkylene glycol chain An acrylic polymer composed of a copolymer having a weight average molecular weight of more than 300,000 and not more than 1 million, obtained by copolymerization of 1.0 to 50 parts by weight of a total of at least one species without containing a copolymerizable monomer having a carboxyl group, wherein the (A) alkyl group has C1 to Of a total of 100 parts by weight of at least two types of C10 alkyl (meth)acrylate, at least 50 parts by weight of 2-ethylhexyl acrylate and at least one monofunctional methacrylate monomer having a homopolymer Tg of 0°C or higher The total is contained in a ratio of 5 to 40 parts by weight, and the pressure-sensitive adhesive composition comprises (C) a trifunctional or higher isocyanate compound as the crosslinking agent, further (D) a crosslinking retarder, and (E) a tin compound as a crosslinking accelerator. A step of preparing a pressure-sensitive adhesive composition comprising a crosslinking accelerator other than, and

Step (2): A step of producing a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition on one side of a base film made of a resin having transparency, and

Step (3): 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 a resin film is bonded through the release agent layer, and the antistatic agent of the release agent layer is attached to the above. The process of transferring to the surface of the pressure-sensitive adhesive layer is produced through the sequence of steps (1) to (3), wherein the release agent layer is a release agent containing dimethylpolysiloxane as a main component, a silicone compound that is a liquid at 20°C, and an antistatic agent. It provides a method for producing an antistatic surface protective film, characterized in that formed by a resin composition containing a.

In addition, the monofunctional methacrylate monomer having a Tg of 0°C or higher of the homopolymer is n-butyl methacrylate, isobutyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, and n-propyl methacrylate. Rate, isopropyl methacrylate, ethyl methacrylate, it is preferably at least one selected from the compound group consisting of methyl methacrylate.

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

In addition, the present invention is an antistatic surface protective film comprising a pressure-sensitive adhesive layer obtained by crosslinking an acrylic polymer and a pressure-sensitive adhesive composition containing a crosslinking agent on one side of a base film made of a resin having transparency, wherein the acrylic polymer comprises ( A) 100 parts by weight in total of at least two or more types of alkyl (meth)acrylates having C1 to C10 carbon atoms in the alkyl group, and (B) 1.0 to 6.0 parts by weight in total of at least one or more copolymerizable monomers containing a hydroxyl group; (F) 1.0 to 50 parts by weight of a total of at least one or more mono(meth)acrylic acid ester monomers comprising a polyalkylene glycol chain constituting the polyalkylene glycol chain, copolymerized without containing a copolymerizable monomer having a carboxyl group. An acrylic polymer consisting of a copolymer having an average molecular weight of more than 300,000 and not more than 1 million, and 2-ethylhexyl in a total of 100 parts by weight of at least two types of alkyl (meth)acrylates having C1 to C10 in the (A) alkyl group A total of at least 50 parts by weight of acrylate and at least one monofunctional methacrylate monomer having a Tg of 0° C. or more of the homopolymer is contained in a ratio of 5 to 40 parts by weight, and the pressure-sensitive adhesive composition comprises ( C) a trifunctional or higher functional isocyanate compound, further comprising (D) a crosslinking retardant and (E) a crosslinking accelerator other than a tin compound as a crosslinking accelerator, on the surface of the pressure-sensitive adhesive layer and on one side of the resin film. A release film on which a release agent layer containing an antistatic agent is laminated is formed by bonding through the release agent layer, the antistatic agent of the release agent layer is transferred to the surface of the pressure sensitive adhesive layer, and the release agent layer is dimethylpolysiloxane An antistatic surface protective film, characterized in that it is formed of a resin composition containing a release agent containing as a main component, a liquid silicone compound at 20°C, and an antistatic agent.

In addition, the monofunctional methacrylate monomer having a Tg of 0°C or higher of the homopolymer is n-butyl methacrylate, isobutyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, and n-propyl methacrylate. Rate, isopropyl methacrylate, ethyl methacrylate, it is preferably at least one selected from the compound group consisting of methyl methacrylate.

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

In addition, the (F) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer constituting the polyalkylene glycol chain has an average repetition number of alkylene oxide constituting the polyalkylene glycol chain is 3 to 14, The diester content in the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer is 0.2% or less, and as the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer, polyalkylene glycol mono(meth)acrylate, methoxy It is preferably at least one or more selected from the group consisting of polyalkylene glycol (meth)acrylate and ethoxypolyalkylene glycol (meth)acrylate.

In addition, it is an antistatic surface protective film used as a surface protective film for a polarizing plate, and in the use of the surface protective film for a polarizing plate, the protective layer of the polarizer of the polarizing plate serving as an adherend is composed of a TAC-based film, a PMMA-based film, and a PET-based film. It is at least one selected from the group, and the surface treatment applied to the surface of the protective layer of the polarizer of the polarizing plate is untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment, and AG-AR treatment. It is preferable that it is at least 1 type selected.

In addition, the (B) copolymerizable monomer containing a hydroxyl group is 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy At least one selected from the group of compounds consisting of oxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and N-hydroxyethyl (meth) acrylamide desirable.

In addition, the (D) crosslinking retardant is a ketoenol tautomer compound, and the (D) crosslinking retardant is contained in an amount of 0.1 to 300 parts by weight based on 100 parts by weight of the acrylic polymer, and the (E ) The crosslinking accelerator is at least one metal chelate compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound, and 0.001 to 0.5 weight of the (E) crosslinking accelerator per 100 parts by weight of the acrylic polymer It contains in a ratio of parts, and it is preferable that the weight part ratio of said (D)/ said (E) is 80-1000.

Further, it is preferable that the pressure-sensitive adhesive composition contains a polyether-modified siloxane compound having an HLB value of 6 to 12 and a weight average molecular weight of 10000 or less in a ratio of 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the acrylic polymer.

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

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

The antistatic surface protective film of the present invention has little contamination with respect to the adherend, and the contamination resistance performance with respect to the adherend does not change with time. Further, according to the present invention, even as an optical film in which the surface of an adherend such as an LR polarizing plate or an AG-LR polarizing plate is anti-staining with a silicone compound or a fluorine compound, it occurs when the antistatic surface protective film is peeled from the adherend. An antistatic surface protective film can be provided that does not deteriorate with time and has excellent peeling antistatic performance.

According to the antistatic surface protective film of the present invention, also in the surface protective film for polarizing plates using PMMA as a base material, (1) balancing the adhesive force in a low-speed peeling rate and a high-speed peeling rate, and (2) fouling resistance performance It can be compatible with having.

In addition, (A) in the alkyl (meth)acrylate having C1 to C10 carbon atoms in the alkyl group, 2-ethylhexyl acrylate and a monofunctional methacrylate monomer having a homopolymer glass transition temperature (Tg) of 0°C or higher. By specifying the content ratio in a specific range, in particular, even in the surface protective film for polarizing plates using PMMA as a base material, (1) balancing the adhesive force in the low-speed peeling rate and the high-speed peeling rate, and (2) fouling resistance performance It can be compatible with having.

On the other hand, to contain one or more monofunctional methacrylate monomers having a Tg of 0°C or higher of the homopolymer (1) to balance the adhesive strength in the low-speed peeling rate and the high-speed peeling rate, and (2) stain resistance It is not clear why it is contributing to making it compatible with having performance. The reason to be considered is that although these methacrylate monomers do not have a polar functional group such as a carboxyl group or an amide group, or a long-chain alkyl group exceeding C10, a polymer having a high Tg is obtained, so that the adhesion performance in the crosslinked state is improved. What can be greatly improved, and in the case of the protective layer of the polarizer of the polarizing plate used as the adherend in the use of the surface protective film for polarizing plates is a PMMA-based film, affinity with methyl methacrylate, which is the main component of the PMMA-based film This improvement and the like are estimated as the reason.

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

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

1 is a cross-sectional view showing the concept of the antistatic surface protective film of the present embodiment. In this antistatic surface protective film 10, an adhesive layer 2 is formed on the surface of one side of the transparent base film 1. The release film 5 in which the release agent layer 4 was formed on the surface of the resin film 3 is pasted on the surface of the pressure-sensitive adhesive layer 2.

As the base film 1 used for the antistatic surface protective film 10 according to the present embodiment, a base film made of a resin having transparency and flexibility is used. Thereby, the external appearance inspection of an optical component can be performed in the state in which the antistatic surface protection film was attached to the optical component which is an adherend. The film made of a transparent resin used as the base film 1 is preferably a polyester film such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and polybutylene terephthalate. In addition to the polyester film, films made of other resins can also be used as long as they have necessary strength and have optical suitability. The base film 1 may be a non-stretched film or a uniaxial or biaxially stretched film. Further, the draw ratio of the stretched film and the orientation angle in the axial direction formed with 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 embodiment 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 If it is thick, it is easy to handle and is more preferable.

Further, if necessary, an antifouling layer, an antistatic layer, an anti-scratch hard coat layer, and the like can be formed on the side opposite to the surface on which the pressure-sensitive adhesive layer 2 of the base film 1 is formed. Further, the surface of the base film 1 may be subjected to an easily bonding treatment such as surface modification by corona discharge and application of an anchor coat agent.

In addition, the pressure-sensitive adhesive layer 2 used in the antistatic surface protective film 10 according to the present embodiment is adhered to the surface of the adherend, and can be easily peeled off after use, and it is difficult to contaminate the adherend. If it is a pressure-sensitive adhesive, it is not particularly limited, but in consideration of durability and the like after bonding to an optical film, it is common to use an acrylic pressure-sensitive adhesive layer obtained by crosslinking an acrylic polymer.

As the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer (2), the acrylic polymer comprises (A) 100 parts by weight in total of at least two or more kinds of alkyl (meth)acrylates having C1 to C10 carbon atoms in the alkyl group, and (B) a hydroxyl group. 1.0 to 6.0 parts by weight of the total of at least one copolymerizable monomer containing, and (F) the sum of at least one or more mono(meth)acrylic acid ester monomers containing polyalkylene glycol chains constituting the polyalkylene glycol chain 1.0 An acrylic polymer composed of a copolymer having a weight average molecular weight of more than 300,000 and not more than 1 million, copolymerized without containing a copolymerizable monomer having a carboxyl group, wherein (A) an alkyl group having C1 to C10 ( Of the total 100 parts by weight of at least two types of meth)acrylate, the sum of at least 50 parts by weight of 2-ethylhexyl acrylate and at least one monofunctional methacrylate monomer having a homopolymer having a Tg of 0°C or higher is 5 to Consisting of 40 parts by weight of the pressure-sensitive adhesive composition, as the crosslinking agent (C) a trifunctional or higher isocyanate compound, further (D) a crosslinking retarder, and (E) a crosslinking accelerator other than a tin compound as a crosslinking accelerator The pressure-sensitive adhesive composition containing is mentioned.

Examples of the (A) alkyl group having C1 to C10 alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylic. Rate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate , Heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl ( Meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like. The alkyl group of these alkyl (meth)acrylates may be acyclic (linear or branched) or cyclic (monocyclic or polycyclic).

In the acrylic polymer, the sum of at least 50 parts by weight of 2-ethylhexyl acrylate and at least one monofunctional methacrylate monomer having a homopolymer having a Tg of 0°C or higher in 100 parts by weight of the total of (A) is 5 to It is preferably contained in a proportion of 40 parts by weight.

In addition, 2-ethylhexyl acrylate is preferably contained in a ratio of 50 parts by weight or more, more preferably in a ratio of 60 parts by weight or more, and a ratio of 70 parts by weight or more, based on the total 100 parts by weight of (A). It is particularly preferable to contain as.

In addition, as monofunctional methacrylate monomers having a Tg of 0°C or higher among the alkyl (meth)acrylates having C1 to C10 carbon atoms in the (A) alkyl group, n-butyl methacrylate, isobutyl methacrylate, s -Butyl methacrylate, t-butyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, ethyl methacrylate, methyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n -At least one selected from the group of compounds consisting of hexyl methacrylate, isohexyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, and dicyclopentamethacrylate. Among these monofunctional methacrylate monomers having a Tg of 0° C. or higher, a methacrylate monomer having a C1-C6 alkyl group is preferred, a methacrylate monomer having a C1-C4 alkyl group is more preferred, and n-butyl Compound group consisting of methacrylate, isobutyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, ethyl methacrylate, and methyl methacrylate It is particularly preferred that it is at least one selected from.

In addition, the total of at least one monofunctional methacrylate monomer having a Tg of 0°C or higher is preferably contained in a ratio of 5 to 40 parts by weight, based on the total 100 parts by weight of (A), and 8 to 40 parts by weight. It is more preferable to contain as, and it is particularly preferable to contain in a proportion of 10 to 35 parts by weight. On the other hand, in the following description, when simply referring to a monomer as Tg, it may refer to the Tg of a homopolymer.

As a copolymerizable monomer containing a hydroxyl group (B) used in the acrylic polymer, 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylic In the compound group consisting of rate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc. It is preferable that it is at least one or more selected.

The acrylic polymer is preferably made of 1.0 to 6.0 parts by weight of the total of at least one copolymerizable monomer containing the (B) hydroxyl group relative to the total 100 parts by weight of the (A), and 2.0 It is more preferable to contain it in a ratio of -6.0 weight part, and it is especially preferable to contain it in a 2.5-5.5 weight part ratio.

The acrylic polymer is preferably copolymerized with (F) a polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer constituting the polyalkylene glycol chain. Further, the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer may be added to the pressure-sensitive adhesive composition as a component different from the acrylic polymer. In either case, the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer can function as an antistatic aid.

The polyalkylene glycol chain-containing 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 contained in the polyalkylene glycol. Since the (meth)acrylic acid ester group becomes a polymerizable group, it can be copolymerized with the acrylic polymer. Polyalkylene glycol mono(meth)acrylate in which the other hydroxyl group is OH as it is, or alkoxypolyalkylene glycol mono(meth)acrylate in which other hydroxyl groups are converted to alkyl ether may be used. On the other hand, since polyalkylene glycol mono(meth)acrylate corresponds to the above (F), even if it contains a hydroxyl group, it is not classified as the above (B).

The polyalkylene glycol constituting the polyalkylene glycol chain may be a glycol compound having one or two or more alkylene groups. For example, polyethylene glycol, polypropylene glycol, polybutylene glycol, polyethylene glycol-poly Propylene glycol, polyethylene glycol-polybutylene glycol, polypropylene glycol-polybutylene glycol, polyethylene glycol-polypropylene glycol-polybutylene glycol, and the like.

It is preferable that the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer has an average repeat number of 3 to 14 of the alkylene oxide constituting the polyalkylene glycol chain. The ``average repetition number of alkylene oxides'' is the average of the repeating number of alkylene oxide units in the ``polyalkylene glycol chains'' part of the molecular structure of the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer. It's a number.

Further, it is preferable that the diester content in the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer is 0.2% or less. "The diester content in a monomer" is the content rate (weight%) of the polyalkylene glycol di(meth)acrylic acid ester contained in the said polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer.

Examples of the polyalkylene glycol chain-containing mono (meth)acrylic acid ester monomer include polyalkylene glycol mono (meth)acrylate, methoxypolyalkylene glycol (meth)acrylate, and ethoxypolyalkylene glycol (meth)acrylic. It is preferable that it is at least one or more selected from the group consisting of a rate.

The acrylic polymer is the polyalkylene glycol chain-containing mono (meth)acrylic acid ester monomer, polyalkylene glycol mono (meth) acrylate, methoxy polyalkylene glycol (meth) acrylate, ethoxy polyalkylene glycol ( It is preferable to copolymerize at least one or more selected from the group consisting of meth) acrylates in a ratio of 1 to 50 parts by weight with respect to 100 parts by weight of the total of (A), and copolymerization in a ratio of 1 to 35 parts by weight. It is more preferable that it is formed, and it is particularly preferable that it is copolymerized in a ratio of 1 to 25 parts by weight.

The method for producing the acrylic polymer is not particularly limited, and appropriately known polymerization methods such as a solution polymerization method and an emulsion polymerization method may be used. The acrylic polymer preferably has a weight average molecular weight of more than 300,000 and 1 million or less. Further, the acrylic polymer is an acrylic polymer copolymerized without containing a copolymerizable monomer having a carboxyl group. It is preferable that the acid value of the acrylic polymer is 0.1 to 1.0. Thereby, the fouling resistance performance can be improved. Here, the "acid value" is one of the indexes indicating the content of the acid, and is represented by the number of mg of potassium hydroxide required to neutralize 1 g of a polymer containing a carboxyl group.

The pressure-sensitive adhesive composition according to the present embodiment further contains (C) a trifunctional or higher isocyanate compound as a crosslinking agent. (C) Examples of trifunctional or higher isocyanate compounds include biuret modified products and isocyanates of diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, and xylylene diisocyanate. And adducts with trivalent or higher polyols such as a rate-modified product, trimethylolpropane, and glycerin. (C) As the ratio of the trifunctional or higher isocyanate compound, for example, it is preferably contained in a ratio of 0.1 to 10 parts by weight, more preferably 0.1 to 6 parts by weight, based on 100 parts by weight of the acrylic polymer. desirable.

The pressure-sensitive adhesive composition according to the present embodiment contains (D) a crosslinking retarder. (D) As a crosslinking retarder, β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, stearyl acetoacetate, acetylacetone, 2,4-hexanedione And β-diketones such as benzoyl acetone. These are ketoenol tautomeric compounds, and (C) by blocking the isocyanate group of the trifunctional or higher isocyanate compound, excessive viscosity increase or gelation of the pressure-sensitive adhesive composition after blending of the crosslinking agent is suppressed, and the pot life of the pressure-sensitive adhesive composition is extended. can do. (D) The crosslinking retardant is particularly preferably at least one or more selected from the group of compounds consisting of acetylacetone and ethyl acetoacetate. It is preferable to contain (D) a crosslinking retardant in an amount of 0.1 to 300 parts by weight based on 100 parts by weight of the acrylic polymer.

The pressure-sensitive adhesive composition according to the present embodiment (E) contains a crosslinking accelerator other than a tin compound as a crosslinking accelerator. (E) The crosslinking accelerator may be a substance that functions as a catalyst for the reaction (crosslinking reaction) of the acrylic polymer and the crosslinking agent when (C) trifunctional or higher isocyanate compounds are used as a crosslinking agent. (E) As a crosslinking accelerator, a metal chelate compound is preferable. The metal chelate compound is a compound in which at least one polydentate ligand L is bonded to a central metal atom M. The metal chelate compound may or may not have at least one monodentate ligand X bonded to the metal atom M. Specific examples of the metal chelate compound include tris (2,4-pentanedionate) iron (III), iron trisacetylacetonate, titanium trisacetylacetonate, ruthenium trisacetylacetonate, zinc bisacetylacetonate, aluminum tris Acetylacetonate, zirconium tetrakisacetylacetonate, tris (2,4-hexanedionate) iron (III), bis (2,4-hexanedionate) zinc, tris (2,4-hexanedionate) titanium, Tris (2,4-hexanedionate) aluminum, tetrakis (2,4-hexanedionate) zirconium, and the like.

(E) The crosslinking accelerator is preferably at least one or more metal chelate compounds selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound. It is preferable to contain (E) a crosslinking accelerator in a proportion of 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the acrylic polymer.

Since the (D) crosslinking retardant has an effect of suppressing crosslinking as opposed to the (E) crosslinking accelerator, it is preferable to appropriately set the ratio of the (D) crosslinking retardant and (E) the crosslinking accelerator. In order to lengthen the pot life of the pressure-sensitive adhesive composition and improve storage stability, the weight part ratio of (D)/(E) is preferably 80 to 1000, more preferably 80 to 700, and 80 to 300. It is particularly preferred. Here, the weight part ratio of (D)/(E) is a value of the quotient obtained by dividing the weight part of (D) by the weight part of (E).

The pressure-sensitive adhesive composition according to the present embodiment may contain (G) a polyether-modified siloxane compound as an optional component. The polyether-modified siloxane compound is a siloxane compound having a polyether group, and in addition to the conventional siloxane unit [-SiR ¹ ₂ -O-], a siloxane unit having a polyether group [-SiR ¹ (R ² O(R ³ O) _n R ⁴ )-O-]. Here, R ¹ is one or two or more alkyl or aryl groups, R ² and R ³ are one or two or more alkylene groups, and R ⁴ is one or two or more alkyl or acyl groups (terminal groups). Show. Examples of the polyether group include polyoxyalkylene groups such as polyoxyethylene group [(C ₂ H ₄ O) _n ] and polyoxypropylene group [(C ₃ H ₆ O) _n ]. In the siloxane unit having a polyether group, the terminal of the polyether group may be an OH group (R ⁴ =H in the above formula).

It is preferable that the polyether-modified siloxane compound is a polyether-modified siloxane compound having an HLB value of 6 to 12. In addition, the polyether-modified siloxane compound is preferably contained in an amount of 0.01 to 0.5 parts by weight, more preferably 0.02 to 0.35 parts by weight, more preferably 0.02 to 0.25 parts by weight, based on 100 parts by weight of the acrylic polymer. It is particularly preferred to contain in a negative proportion. The HLB value is, for example, a hydrophilic lipophilic balance (hydrophilic lipophilicity ratio) prescribed by JIS K3211 (terminal surfactant).

The polyether-modified siloxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane main chain having a silicon hydride group by hydrosilylation reaction. Specifically, dimethylsiloxane/methyl (polyoxyethylene) siloxane copolymer, dimethylsiloxane/methyl (polyoxyethylene) siloxane/methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane/methyl (polyoxypropylene) siloxane polymer, etc. Can be mentioned.

By blending the polyether-modified siloxane compound into the pressure-sensitive adhesive composition, it is possible to improve the adhesion and rework performance of the pressure-sensitive adhesive layer. It is preferable that the weight average molecular weight of the said polyether-modified siloxane compound is 10000 or less. From the viewpoint of compatibility with the acrylic polymer, a low HLB value and a low molecular weight have good compatibility, but a polyether-modified siloxane compound having a low molecular weight has a relatively high HLB value and is excellent even if the compatibility with the acrylic polymer is slightly low. Antistatic properties are obtained.

The pressure-sensitive adhesive composition of the present embodiment is not limited to the above-described additives, and known additives such as surfactants, curing accelerators, plasticizers, fillers, curing retardants, processing aids, anti-aging agents, and antioxidants may be appropriately blended. These may be used alone or in combination of two or more.

The thickness of the pressure-sensitive adhesive layer 2 used in the antistatic surface protective film 10 according to the present embodiment is not particularly limited, but, for example, a thickness of about 5 to 40 µm is preferable, and 10 to 30 µm The thickness of about is more preferable. When peeling the antistatic surface protective film from the adherend, the pressure-sensitive adhesive layer 2 having a non-adhesive force of about 0.03 to 0.3 N/25 mm of the peel strength (adhesion force) of the antistatic surface protective film to the surface of the adherend It is preferable from the viewpoint of excellent operability. In addition, in terms of excellent operability when peeling the release film 5 from the antistatic surface protective film 10, the peeling force of the release film 5 from the pressure-sensitive adhesive layer 2 is 0.2 N/50 mm or less. desirable.

In addition, the release film 5 used in the antistatic surface protective film 10 according to the present embodiment includes a release agent containing dimethylpolysiloxane as a main component on one side of the resin film 3, and a silicone compound which is a liquid at 20°C. And, the release agent layer 4 is formed of a resin composition containing an antistatic agent.

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 a polyester film is particularly preferred in view of excellent transparency and relatively low price. . The resin film may be a non-stretched film or a uniaxial or biaxially stretched film. Further, the draw ratio of the stretched film and the orientation angle in the axial direction formed with crystallization of the stretched film may be controlled to a specific value.

Although the thickness of the resin film 3 is not particularly limited, for example, a thickness of about 12 to 100 µm is preferable, and a thickness of about 20 to 50 µm is more preferable for easy handling.

Further, if necessary, the surface of the resin film 3 may be subjected to easy adhesion treatment such as surface modification by corona discharge and application of an anchor coat agent.

Examples of the release agent containing dimethylpolysiloxane constituting the release agent layer 4 as a main component include known silicone release agents such as addition reaction type, condensation reaction type, cationic polymerization type, and radical polymerization type. Products marketed as addition reaction silicone-based release agents include, for example, KS-776A, KS-847T, KS-779H, KS-837, KS-778, KS-830 (manufactured by Shin-Etsu Chemical Co., Ltd.), and 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. As a condensation reaction type, commercially available products include, for example, SRX-290 and SYLOFF-23 (manufactured by Toray Dow Corning Co., Ltd.). Products marketed as cationic polymerization types 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 the like. As a product marketed as a radical polymerization type, X62-7205 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. are mentioned, for example.

Examples of the silicone-based compound that is a liquid at 20° C. constituting the release agent layer 4 include polyether-modified silicone, alkyl-modified silicone, carbinol higher fatty acid ester-modified silicone, and the like. In this embodiment, in order to improve the antistatic property on the surface of the pressure-sensitive adhesive layer, a silicone-based compound that is a liquid at 20°C in a state of being compatible in a release agent layer containing dimethylpolysiloxane as a main component is used. Among the modified silicone compounds, polyether-modified silicone is preferred for the use of the present embodiment. 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 in the side chain, compatibility with a silicone release agent or antistatic effect, etc. Physical properties are adjusted.

In addition, products marketed as polyether-modified silicone include, for example, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, and 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 liquid silicone compound added at 20°C to the release agent containing dimethylpolysiloxane as a main component varies depending on the type of silicone compound or the degree of compatibility with the release agent, but is required when peeling the antistatic surface protective film from the adherend. It may be set in consideration of the required peeling voltage, contamination resistance to the adherend, and adhesion characteristics.

It is preferable that the antistatic agent constituting the release agent layer 4 has good dispersibility in a release agent solution containing dimethylpolysiloxane as a main component, and does not inhibit curing of the release agent containing dimethylpolysiloxane as a main component. As such an antistatic agent, an alkali metal salt is preferable. Examples of the alkali metal salt include metal salts composed of lithium, sodium, and potassium. Specifically, for example, Li ^+, Na ^+, and cations consisting of ^{K +, Cl -, Br -} , I -, BF 4 -, PF 6 -, SCN -, ClO 4 -, CF 3 SO 3 - ^{_{, (FSO 2) 2 N -}} , (CF 3 SO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, (CF 3 SO 2) 3 C - anion to metal salt is preferably constituted by comprising the Used. In particular, it is preferable that the antistatic agent in the release agent layer 4 is a Li salt, and is at least one selected from the group of compounds consisting of LiTFSI, LiFSI, and LiTF. Here, LiTFSI represents Li(CF ₃ SO ₂ ) ₂ N. In addition, LiFSI represents Li(FSO ₂ ) ₂ N. In addition, LiTF represents LiCF ₃ SO ₃ . These alkali metal salts may be used alone or in combination of two or more. In order to stabilize the ionic substance, a compound containing a polyoxyalkylene structure may be added.

The amount of antistatic agent added to the release agent containing dimethylpolysiloxane as a main component varies depending on the type of antistatic agent or the degree of affinity with the release agent, but the peeling voltage required when peeling the antistatic surface protective film from the adherend, and the adherend It can be set in consideration of contamination resistance and adhesion properties.

There is no particular limitation on the mixing method of the release agent containing dimethylpolysiloxane as a main component and the polyether-modified silicone and the antistatic agent. A method of adding and mixing a catalyst for curing the release agent after adding and mixing polyether-modified silicone and an antistatic agent to a release agent containing dimethylpolysiloxane as a main component, and denatures polyether after diluting a release agent containing dimethylpolysiloxane as a main component with an organic solvent in advance. A method of adding and mixing a catalyst for curing silicone, an antistatic agent, and a release agent, and after diluting a release agent containing siloxane as a main component in an organic solvent in advance, adding and mixing the catalyst, and then adding and mixing polyether-modified silicone and an antistatic agent Any method, such as a method of doing it, may be used. Further, if necessary, an adhesion improving agent such as a silane coupling agent or a material that aids in antistatic effect such as a compound containing a polyoxyalkylene group may be added.

The mixing ratio of the release agent containing dimethylpolysiloxane as a main component, the polyether-modified silicone and the antistatic agent is not particularly limited, but a polyether-modified silicone and an antistatic agent are used as a solid content based on 100 parts by weight of the solid content of the release agent containing dimethylpolysiloxane as a main component. A weight ratio of about 5 to 100 parts by weight is preferred. If the amount of polyether-modified silicone and antistatic agent added in terms of solid content is less than 5 parts by weight relative to 100 parts by weight of the solid content of the release agent containing dimethylpolysiloxane as a main component, the amount of antistatic agent transferred to the surface of the pressure-sensitive adhesive layer will also decrease and charge the adhesive. It becomes difficult to exhibit the function of prevention. In addition, if the added amount of polyether-modified silicone and antistatic agent in terms of solid content exceeds 100 parts by weight of 100 parts by weight of solid content of a release agent containing dimethylpolysiloxane as a main component, dimethylpolysiloxane is the main component together with polyether-modified silicone and antistatic agent. Since the release agent to be used is transferred to the surface of the pressure-sensitive adhesive layer, there is a possibility that the adhesive properties of the pressure-sensitive adhesive are deteriorated.

The method of forming the pressure-sensitive adhesive layer 2 and the method of bonding the release film 5 to the base film 1 of the antistatic surface protective film 10 according to the present embodiment may be performed by a known method, and is particularly limited. It doesn't work. Specifically, (1) a method of bonding the release film 5 after forming a pressure-sensitive adhesive layer by applying and drying a resin composition for forming the pressure-sensitive adhesive layer 2 on one side of the base film 1, (2 ) A method of applying and drying a resin composition for forming the pressure-sensitive adhesive layer 2 on the surface of the release film 5 to form a pressure-sensitive adhesive layer, and then bonding the base film 1, etc. may be mentioned. Also works.

In addition, 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.

In addition, similarly, forming the release agent layer 4 on the resin film 3 may be performed by a known method. Specifically, known coating methods such as gravure coating, Mayer bar coating, and air knife coating can be used.

2 is a cross-sectional view showing a state in which the release film 5 is peeled from the antistatic surface protection film 10. Part of the antistatic agent 7 included in the release agent layer 4 of the release film 5 by peeling the release film 5 from the antistatic surface protection film 10 shown in FIG. 1 is an antistatic surface protection film It is transferred (attached) to the surface of the pressure-sensitive adhesive layer 2 of (10). For this reason, 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 represented by a spot of 7.

In the antistatic surface protective film according to the present embodiment, in bonding the antistatic surface protective film 11 in a state in which the release film shown in FIG. 2 has been peeled off to an adherend, transferred to the surface of the pressure-sensitive adhesive layer 2 The antistatic agent 7 contacts the surface of the adherend. Thereby, the peeling electrification voltage at the time of peeling the antistatic surface protective film again from an adherend can be suppressed low. On the other hand, in addition to the antistatic agent 7, a liquid silicone compound may be transferred from the release agent layer 4 to the surface of the pressure-sensitive adhesive layer 2 at 20°C.

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

From the antistatic surface protective film 10 according to the present embodiment, the peeling film 5 is peeled off, and the pressure-sensitive adhesive layer 2 is exposed, and the optical component 8 as an adherend through the pressure-sensitive adhesive layer 2 ) Is attached to.

That is, in FIG. 3, the optical component 20 to which the antistatic surface protective film 10 of this embodiment was pasted is shown. As optical parts, optical films, such as a polarizing plate, a retardation plate, a lens film, a retardation plate combined polarizing plate, and a lens film combined polarizing plate, are mentioned. Such optical components are used as constituent members of liquid crystal display devices such as liquid crystal display panels and optical system devices of various instruments. Moreover, as an optical component, films for optics, such as an antireflection film, a hard coat film, and a transparent conductive film for touch panels, are also mentioned. In particular, the surface is bonded to the stain-resistant surface of an optical film such as a low-reflective treatment polarizing plate (LR polarizing plate) or an anti-glare low-reflection treatment polarizing plate (AG-LR polarizing plate) that is anti-staining from a silicone compound or a fluorine compound. It can be preferably used as an antistatic surface protective film.

According to the optical component of the present embodiment, when peeling and removing the antistatic surface protective film 10 from an optical component (optical film) as an adherend, since the peeling electrification voltage can be sufficiently low, the driver IC, the TFT element, There is no fear of destroying circuit components such as a gate line driving circuit, and production efficiency in a process of manufacturing a liquid crystal display panel or the like can be improved, and reliability of the production process can be maintained.

The antistatic surface protective film 10 of this embodiment is preferable as a surface protective film for polarizing plates. The pressure-sensitive adhesive layer 2 of the antistatic surface protective film 10 may be bonded to the protective layer of the polarizer of the polarizing plate. Here, in the use of the surface protective film for polarizing plates, at least one or more selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film as the protective layer of the polarizer of the polarizing plate serving as an adherend. Here, TAC is an abbreviation of triacetyl cellulose, PMMA is polymethyl methacrylate, and PET is an abbreviation of polyethylene terephthalate.

In addition, in the use of the surface protective film for polarizing plates, the surface treatment applied to the surface of the protective layer of the polarizer of the polarizing plate as an adherend is untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment, and AG-AR treatment. It may be at least one or more selected from the group consisting of. Here, AG refers to anti-glare, LR refers to low reflection, and AR refers to anti-reflection.

In the antistatic surface protective film 10 of the present embodiment, the surface resistivity of the pressure-sensitive adhesive layer 2 obtained by crosslinking the pressure-sensitive adhesive composition to which the antistatic agent of the release agent layer 4 has been transferred is 1.0×10 ⁺¹² Ω/□ or less. It is preferable, and it is more preferable that it is 5.0×10 ⁺¹¹ Ω/□ or less, and particularly preferably 1.0×10 ⁺¹¹ Ω/□ or less. When the surface resistivity of the pressure-sensitive adhesive layer 2 is large, the ability to pass static electricity generated when the pressure-sensitive adhesive layer 2 is peeled from the adherend is inferior. Therefore, by making the surface resistivity of the pressure-sensitive adhesive layer 2 sufficiently small, the peeling electrification voltage caused by static electricity generated when the pressure-sensitive adhesive layer 2 is peeled from the adherend is reduced, thereby suppressing the influence on the adherend. can do.

In the antistatic surface protective film 10 of the present embodiment, the pressure-sensitive adhesive layer 2 obtained by crosslinking the pressure-sensitive adhesive composition to which the antistatic agent of the release agent layer 4 is transferred is a composition for forming a low refractive index layer containing a fluorine compound It is preferable that the peeling electrification voltage of the pressure-sensitive adhesive layer 2 with respect to the low refractive index layer formed by using is within the range of +0.3 to -0.3 kV. As a fluorine compound used in the composition for forming a low refractive index layer, a fluorinated copolymer such as one or two or more polymers such as fluorinated olefins, fluorinated vinyl ethers, and fluorinated alkyl (meth)acrylates, and silane compounds containing fluorinated alkyl groups Condensation products, such as are mentioned. In addition to the fluorinated monomer, the fluorinated copolymer may be copolymerized with a non-fluorinated monomer such as olefins, vinyl ethers, and (meth)acrylates. The low refractive index layer may be combined with a high refractive index layer or the like to form an antireflection layer.

When measuring the peeling electrification voltage with respect to the low refractive index layer, PMMA substrates and TAC substrates may be mentioned as the substrate for forming the low refractive index layer on the surface. In addition, in the antistatic surface protective film 10 of the present embodiment, the pressure-sensitive adhesive layer 2 obtained by crosslinking the pressure-sensitive adhesive composition to which the antistatic agent of the release agent layer 4 is transferred is treated on the surfaces of the PMMA substrate and the TAC substrate. It is preferable that the peeling electrification voltage for the unfinished plain layer is in the range of +0.3 to -0.3 kV.

When the pressure-sensitive adhesive layer 2 was bonded to an adherend such as a polarizing plate, left to stand for 2 days (48 hours) in an atmosphere of a temperature of 60° C. and a humidity of 90% RH, taken out under the above atmosphere, and then peeled after 1 day elapsed It is desirable that there is no contamination. Examples of the adherend include a polarizing plate in which a protective layer is laminated on a polarizer, and the surface of the protective layer is treated with a low-reflection surface with a composition containing a fluorine compound. The composition containing the fluorine compound used for the low-reflection surface treatment may be the same as or different from the resin composition for forming a low refractive index layer containing the fluorine compound described above. As the protective layer and the surface treatment, the protective layer of the above-described polarizer and the surface treatment applied to the surface thereof are exemplified. Specifically, the surface substrate is one selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film, and the surface treatment applied to the surface of the surface substrate is untreated, AG treatment, LR treatment, AR A polarizing plate which is one type selected from the group consisting of treatment, AG-LR treatment, and AG-AR treatment can be mentioned.

In the antistatic surface protective film 10 of the present embodiment, a pressure-sensitive adhesive layer 2 obtained by crosslinking the pressure-sensitive adhesive composition to which the antistatic agent of the release agent layer 4 has been transferred is placed on one side of a 38 μm-thick polyester film, After the antistatic surface protective film 10 laminated to a thickness of 15 μm is adhered to the surface of the polarizing plate, when peeling the antistatic surface protective film 10 from the polarizing plate, a low-speed peeling rate of 0.3 m/min It is preferable that the adhesive force is 0.01 to 0.1 N/25 mm, the adhesive force at a high-speed peeling speed of 30 m/min is 1.0 N/25 mm or less, and the adhesive force at a high-speed peeling speed of 30 m/min is 0.2 to 0.8 N/25 mm. More preferable. Thereby, the performance in which the adhesive force has little change even with the peeling speed is obtained, and it becomes possible to peel quickly even by high-speed peeling. Further, for reattachment, even when the antistatic surface protection film 10 is once peeled off, an excessive force is not required, and it is easy to peel from the adherend.

In the antistatic surface protective film 10 of this embodiment, the gel fraction of the pressure-sensitive adhesive layer 2 obtained by crosslinking the pressure-sensitive adhesive composition to which the antistatic agent of the release agent layer 4 is transferred is preferably 95 to 100%, It is more preferable that it is 97-100%. As described above, the high gel fraction of the pressure-sensitive adhesive layer 2 does not increase the adhesive strength at a low-speed peeling rate, and the elution of unpolymerized monomers or oligomers from the pressure-sensitive adhesive layer 2 is reduced, and reworkability and high temperature/high humidity. It is possible to suppress the contamination of the adherend by improving the durability in the.

The adhesive film of this embodiment is formed by forming an adhesive layer obtained by crosslinking the adhesive composition of this embodiment on one side or both sides of a resin film. In addition, the surface protection film of this embodiment is a surface protection film obtained by forming an adhesive layer formed by crosslinking the adhesive composition of this embodiment on one side of a resin film. The surface protective film of this embodiment becomes an antistatic surface protective film by transferring the antistatic agent of the release agent layer 4 to the surface of the pressure-sensitive adhesive layer 2, and has excellent antistatic performance. In addition, the antistatic surface protective film of the present embodiment has excellent balance of adhesive force in a low-speed peeling speed and a high-speed peeling speed, and further has stain resistance. For this reason, it can be used suitably as the use of the surface protection film of a polarizing plate.

Further, by laminating the pressure-sensitive adhesive layer 2 obtained by crosslinking the pressure-sensitive adhesive composition to which the antistatic agent of the release agent layer 4 has been transferred, on at least one side of the optical film, an optical film with a pressure-sensitive adhesive layer can be obtained. As an optical film, a polarizing film, a retardation film, an antireflection film, an anti-glare (anti-glare) film, an ultraviolet absorbing film, an infrared absorbing film, an optical compensation film, a brightness improving film, etc. are mentioned. Devices to which the optical member is applied include a liquid crystal panel, an organic EL panel, and a touch panel.

In the case of an optical surface protective film and an adhesive film such as a surface protective film for a polarizing plate, it is preferable that the base film and the adhesive layer have sufficient transparency.

Example

Hereinafter, the present invention will be described in detail with reference to examples.

<Preparation of adhesive composition>

[Example 1]

Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, and air in the reaction apparatus was replaced with nitrogen gas. Then, 80 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of n-butyl methacrylate, 4.5 parts by weight of 8-hydroxyoctyl acrylate, and 10 parts by weight of polypropylene glycol monoacrylate (n=12) A solvent (ethyl acetate) was added together with the part. Thereafter, 0.1 parts 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. To this acrylic polymer solution, 8.5 parts by weight of acetylacetone was added and stirred, and then coronate HX (isocyanurate of hexamethylene diisocyanate compound) was added in 2.0 parts by weight, titanium trisacetylacetonate 0.1 parts by weight, polyether 0.05 parts by weight of a modified siloxane compound (HLB=7) was added and mixed with stirring to obtain the pressure-sensitive adhesive composition of Example 1.

[Examples 2 to 6 and Comparative Examples 1 to 4]

Except having made the composition of the adhesive composition of Example 1 the same as the description in Table 1, respectively, it carried out similarly to Example 1, and obtained the adhesive compositions of Examples 2-6 and Comparative Examples 1-4. In the case of the pressure-sensitive adhesive composition of Comparative Examples 1 and 2, the compound shown in the "antistatic agent" of Table 2 was further added to the pressure-sensitive adhesive composition. On the other hand, the acrylic polymers of Examples 1 to 6 and Comparative Examples 1 to 3 were copolymers having a weight average molecular weight of more than 300,000 and 1 million or less. The acrylic polymer of Comparative Example 4 was a copolymer having a weight average molecular weight of 100,000.

In each column of Table 1 and the "antistatic agent" of Table 2, parts by weight of each component were calculated as 100 parts by weight of the total amount of alkyl (meth)acrylates having C1 to C10 in the (A) alkyl group. "(D)/(E)" in Table 2 is a weight part ratio. In addition, in each column of (B) to (G) of Table 1, the content ratio of each component when the weight part of the acrylic polymer calculated as the sum of the weight parts of (A), (B), and (F) is 100 parts by weight. (Parts by weight) is represented by a numerical value in parentheses (). In addition, in the "antistatic agent" of Table 2, LiTFSI represents Li(CF ₃ SO ₂ ) ₂ N, and LiTF represents LiCF ₃ SO ₃ .

In addition, the compound names of the abbreviations of each component of (A) to (G) used in Table 1 are shown in Table 3. Meanwhile, Coronate (registered trademark) HX, HL, and L are brand names of Tosoh Corporation, and Takenate (registered trademark) D-140N and D-110N are brand names of Mitsui Chemicals Corporation.

In addition, (F) of the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomers constituting the polyalkylene glycol chain, F-1 to F-3 are monomers having a diester content of 0.2 wt% or less, and F-4 is It is a monomer having a diester content of 0.8 wt%. The value of n represents the average repetition number of the alkylene oxide.

In addition, in the (G) polyether-modified siloxane compound, the weight average molecular weight of G-1 to G-6 is 10000 or less.

<Production of antistatic surface protective film>

[Example 1]

Addition-reactive silicone (manufactured by Toray Dow Corning, product name: SRX-345) 5 parts by weight, polyether-modified silicone (manufactured by Toray Dow Corning, product name: SH8400) 0.15 parts by weight, lithium bis( 0.5 parts by weight of trifluoromethanesulfonyl)imide salt (LiTFSI), 95 parts by weight of a 1:1 mixed solvent of toluene and ethyl acetate, and a platinum catalyst (manufactured by Toray Dow Corning Co., Ltd., product name: SRX-212 Catalyst) ) 0.05 parts by weight was mixed, stirred and mixed, to prepare a paint for forming the release agent layer of Example 1. On the surface of a polyethylene terephthalate film having a thickness of 38 μm, the paint for forming the release agent layer of Example 1 was applied immediately so that the thickness after drying became 0.2 μm, and dried in a hot air circulation oven at 120° C. for 1 minute. The release film of Example 1 was obtained.

The pressure-sensitive adhesive composition of Example 1 was applied to the surface of a polyethylene terephthalate film having a thickness of 38 μm to a thickness of 15 μm after drying, and then dried in a hot air circulation oven at 100° C. for 2 minutes to form a pressure-sensitive adhesive layer. Then, the release agent layer (silicon treated surface) of the release film of Example 1 produced above was attached to the surface of this pressure-sensitive adhesive layer. The obtained adhesive film was kept warm for 5 days in an environment at 40°C, and the adhesive was cured to obtain an antistatic surface protective film of Example 1.

[Examples 2 to 6]

Except that the composition of the coating material for forming the release agent layer of Example 1 was the same as the description in Table 4, respectively, in the same manner as in Example 1, a coating material for forming the release agent layer of Examples 2 to 6 was obtained.

In addition, in the same manner as in Example 1, except that the pressure-sensitive adhesive composition of Example 1 and the paint for forming the release agent layer were used as the pressure-sensitive adhesive composition of Examples 2 to 6 and the paint for forming the release agent layer, respectively, An antistatic surface protective film was obtained.

[Comparative Example 1]

Addition-reactive silicone (manufactured by Toray Dow Corning Co., Ltd., product name: SRX-345) 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 part by weight was mixed, stirred and mixed, and a coating material for forming a release agent layer of Comparative Example 1 was prepared. On the surface of a polyethylene terephthalate film having a thickness of 38 μm, the paint for forming the release agent layer of Comparative Example 1 was applied immediately so that the thickness after drying became 0.2 μm, and dried for 1 minute in a hot air circulation oven at 120° C. for comparison The release film of Example 1 was obtained.

The pressure-sensitive adhesive composition of Comparative Example 1 was applied to a surface of a polyethylene terephthalate film having a thickness of 38 μm to a thickness of 15 μm after drying, and then dried in a hot air circulation oven at 100° C. for 2 minutes to form a pressure-sensitive adhesive layer. Then, the release agent layer (silicon treated surface) of the release film of Comparative Example 1 produced above was pasted on the surface of this pressure-sensitive adhesive layer. The obtained adhesive film was kept warm for 5 days in an environment at 40°C, and the adhesive was cured to obtain an antistatic surface protective film of Comparative Example 1.

[Comparative Example 2]

Except having used the adhesive composition of Comparative Example 1 as the adhesive composition of Comparative Example 2, it carried out similarly to Comparative Example 1, and obtained the antistatic surface protective film of Comparative Example 2.

[Comparative Examples 3 to 4]

Except that the composition of the coating material for forming the release agent layer of Example 1 was the same as the description in Table 4, respectively, in the same manner as in Example 1, a coating material for forming the release agent layer of Comparative Examples 3 to 4 was obtained. In addition, the pressure-sensitive adhesive composition of Example 1 and the coating material for forming the release agent layer were used as the pressure-sensitive adhesive composition of Comparative Examples 3 to 4 and the coating material for forming the release agent layer, respectively, in the same manner as in Example 1, An antistatic surface protective film was obtained.

On the other hand, in the "antistatic agent" of Table 4, LiTFSI represents Li(CF ₃ SO ₂ ) ₂ N, LiFSI represents Li(FSO ₂ ) ₂ N, and LiTF represents LiCF ₃ SO ₃ .

<Test method and evaluation>

The antistatic surface protective films in Examples 1 to 6 and Comparative Examples 1 to 4 were aged for 7 days in an atmosphere at a temperature of 23°C and a humidity of 50% RH, respectively, and then evaluated by the following test methods. On the other hand, in the antistatic surface protective films of Examples 1 to 6 and Comparative Examples 3 to 4, by peeling the release film, the antistatic agent of the release agent layer can be transferred to the surface of the pressure-sensitive adhesive layer. In Comparative Examples 1 to 2, the entire pressure-sensitive adhesive layer contains an antistatic agent.

<Test method of adhesive force>

The release film was peeled off, and the antistatic surface protective film exposing the pressure-sensitive adhesive layer having a thickness of 15 μm was bonded to the surface of the polarizing plate through the pressure-sensitive adhesive layer, and left to stand for 1 day, then, at 50° C., 5 atm, and automatically for 20 minutes. What was claved and left for an additional 12 hours at room temperature was used as a sample for measuring adhesion. The obtained measurement sample was peeled at a low speed (0.3 m/min) or a high speed (30 m/min) using a tensile tester in the 180° direction, and the measured peel strength was taken as the adhesive force.

Here, the protective layer of the polarizer of the polarizing plate is polymethyl methacrylate (PMMA) having an AG-LR treatment layer.

<Test method of surface resistivity>

After aging the antistatic surface protective film, before bonding to the polarizing plate, peel the release film to expose the pressure-sensitive adhesive layer, and use a resistivity meter Hiresta (registered trademark) UP-HT450 (manufactured by Mitsubishi Chemical Analytech). The surface resistivity of the layer was measured.

<Test method of peeling large voltage>

The release film was peeled off, and the antistatic surface protective film in which the pressure-sensitive adhesive layer was exposed was bonded to a polarizing plate having a low refractive index layer formed using a composition for forming a low refractive index layer containing a fluorine compound on the adherend surface. When the antistatic surface protective film is peeled 180° at a tensile speed of 30m/min, the voltage (high voltage) generated by charging the adherend is measured using high-precision electrostatic sensors SK-035 and SK-200 (manufactured by Keyence Corporation). It measured, and the maximum value of the measured value was made into the peeling electric voltage.

<Test method of contamination resistance>

On one side of the glass plate, the surface base material shown in Table 6 and the polarizing plate having the surface treatment (untreated in the case of Plain) were bonded using a bonding machine via an adhesive layer (double-sided adhesive tape). Then, the antistatic surface protective film was attached to the surface of the polarizing plate using a bonding machine. After bonding to the adherend, it was allowed to stand for 2 days (48 hours) in an atmosphere of a temperature of 60° C. and a humidity of 90% RH, and after taking out under the above atmosphere, after 1 day elapsed, the antistatic surface protective film was peeled off the surface of the polarizing plate. The contamination state of was observed with the naked eye. As a criterion for determining the fouling resistance, when there was no contamination on the surface of the polarizing plate, "○" was evaluated, when there was a little contamination, "Δ", and when there was contamination, "x" was evaluated.

In Tables 5 to 6, the evaluation results of the antistatic surface protective films of Examples 1 to 6 and Comparative Examples 1 to 4 are shown. The "surface resistivity" in Table 5 was expressed by a method in which "m×10 ⁺ⁿ " is "mE+n" (where m is an arbitrary real value, and n is a positive integer).

The antistatic surface protective films of Examples 1 to 6 had an adhesive strength of 0.01 to 0.1 N/25 mm to a polarizing plate as an adherend at a low-speed peeling speed of 0.3 m/min, and an adhesive force of 1.0 N at a high-speed peeling speed of 30 m/min. From the point of /25 mm or less, the adhesive performance by balancing the adhesive force was excellent in the low-speed peeling speed and the high-speed peeling speed.

In addition, since the antistatic surface protective film of Examples 1 to 6 transfers the antistatic agent of the release agent layer to the surface of the pressure sensitive adhesive layer, the surface resistivity of the pressure sensitive adhesive layer is 1.0 × 10 ⁺¹² Ω/□ or less, and contains a fluorine compound. The peeling electrification voltage of the pressure-sensitive adhesive layer to the low-refractive-index layer formed using the composition for forming a low-refractive-index layer was in the range of +0.3 to -0.3 kV, and the antistatic performance was excellent.

In addition, after bonding the antistatic surface protective films of Examples 1 to 6 to the adherend, they were left to stand for 48 hours in an atmosphere of a temperature of 60°C and a humidity of 90% RH, and even after taking out from the atmosphere for 1 day, various polarizing plates as adherends were There was no contamination, and the contamination resistance was excellent.

That is, according to the evaluation results shown in Tables 5-6, it is demonstrated that the antistatic surface protective film of Examples 1-6 was able to solve the subject of this invention.

Antistatic surface protection film of Comparative Example 1 (Tg of the monofunctional methacrylate monomer copolymerized with an acrylic polymer is less than 0°C, the entire pressure-sensitive adhesive layer contains an antistatic agent, and the release agent layer is a liquid silicone type at 20°C Compound and antistatic agent were not included), the stain resistance performance was slightly poor.

In addition, the antistatic surface protective film of Comparative Example 2 (a monofunctional methacrylate monomer copolymerized with an acrylic polymer and a hydroxyl group-containing monomer are excessive, and the acrylic polymer is a polyalkylene glycol chain-containing mono( It does not contain meth)acrylic acid ester monomer, contains an antistatic agent in the entire pressure-sensitive adhesive layer, and the release agent layer does not contain a liquid silicone compound and an antistatic agent at 20°C.) It was high, and the anti-pollution performance was poor.

In addition, the antistatic surface protective film of Comparative Example 3 (the acrylic polymer does not contain a methacrylate monomer having a Tg of 0°C or higher, and a polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer constituting a polyalkylene glycol chain, , Containing a carboxyl group-containing monomer) had high adhesive strength, high surface resistance, high peeling voltage, and poor stain resistance.

Further, the antistatic surface protective film of Comparative Example 4 (the weight average molecular weight of the acrylic polymer was small) was poor in stain resistance.

Thus, in the antistatic surface protective film of Comparative Examples 1 to 4, the subject of the present invention could not be solved.

One… Base film, 2... Adhesive layer, 3... Resin film, 4... Release agent layer, 5... Release film, 7... Antistatic agent, 8... Adherend (optical part), 10... Antistatic surface protection film, 11... Antistatic surface protective film from which the peeling film was peeled off, 20... Optical parts with antistatic surface protection film attached.

Claims (13)

As a manufacturing method of an antistatic surface protective film, the following steps (1) to (3),
Step (1): As an adhesive composition containing an acrylic polymer and a crosslinking agent, the acrylic polymer,
(A) 100 parts by weight in total of at least two or more types of alkyl (meth)acrylates having C1 to C10 in the alkyl group,
(B) 1.0 to 6.0 parts by weight in total of at least one or more copolymerizable monomers containing a hydroxyl group,
(F) 1.0 to 50 parts by weight of a total of at least one or more mono(meth)acrylic acid ester monomers comprising a polyalkylene glycol chain constituting the polyalkylene glycol chain, copolymerized without containing a copolymerizable monomer having a carboxyl group. It is an acrylic polymer composed of a copolymer having an average molecular weight of more than 300,000 and not more than 1 million,
(A) In a total of 100 parts by weight of at least two or more types of alkyl (meth)acrylates having C1 to C10 carbon atoms in the alkyl group, 50 parts by weight or more of 2-ethylhexyl acrylate, and the Tg of the homopolymer is 0°C or more. Consisting of containing the sum of at least one type of monofunctional methacrylate monomer in a ratio of 5 to 40 parts by weight,
The step of producing a pressure-sensitive adhesive composition in which the pressure-sensitive adhesive composition contains (C) an isocyanate compound having trifunctional or higher functionality as the crosslinking agent, further (D) a crosslinking retardant, and (E) a crosslinking accelerator other than a tin compound as a crosslinking accelerator and,
Step (2): A step of producing a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition on one side of a base film made of a resin having transparency, and
Step (3): 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 a resin film is bonded through the release agent layer, and the antistatic agent of the release agent layer is attached to the above. Process of transferring to the surface of the adhesive layer
Is produced through the sequence of steps (1) to (3),
The method for producing an antistatic surface protective film, wherein the release agent layer is formed of a resin composition containing a release agent containing dimethylpolysiloxane as a main component, a liquid silicone compound at 20°C, and an antistatic agent. The method of claim 1,
Monofunctional methacrylate monomers having a Tg of 0°C or higher of the homopolymer are n-butyl methacrylate, isobutyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, n-propyl methacrylate, Method for producing an antistatic surface protection film, characterized in that at least one selected from the group of compounds consisting of isopropyl methacrylate, ethyl methacrylate, and methyl methacrylate. The method according to claim 1 or 2,
The method for producing an antistatic surface protective film, wherein the antistatic agent in the release agent layer is an alkali metal salt. An antistatic surface protective film comprising a pressure-sensitive adhesive layer formed by crosslinking an acrylic polymer and a pressure-sensitive adhesive composition containing a crosslinking agent on one side of a base film made of a resin having transparency,
The acrylic polymer,
(A) 100 parts by weight in total of at least two or more types of alkyl (meth)acrylates having C1 to C10 in the alkyl group,
(B) 1.0 to 6.0 parts by weight in total of at least one or more copolymerizable monomers containing a hydroxyl group,
(F) 1.0 to 50 parts by weight of a total of at least one or more mono(meth)acrylic acid ester monomers comprising a polyalkylene glycol chain constituting the polyalkylene glycol chain, copolymerized without containing a copolymerizable monomer having a carboxyl group. It is an acrylic polymer composed of a copolymer having an average molecular weight of more than 300,000 and not more than 1 million,
(A) In a total of 100 parts by weight of at least two or more types of alkyl (meth)acrylates having C1 to C10 carbon atoms in the alkyl group, 50 parts by weight or more of 2-ethylhexyl acrylate, and the Tg of the homopolymer is 0°C or more. Consisting of containing the sum of at least one type of monofunctional methacrylate monomer in a ratio of 5 to 40 parts by weight,
The pressure-sensitive adhesive composition comprises (C) a trifunctional or higher isocyanate compound as the crosslinking agent, further (D) a crosslinking retarder, and (E) a crosslinking accelerator other than a tin compound as a crosslinking accelerator,
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 resin film is bonded through the release agent layer, and the antistatic agent of the release agent layer is Is transferred to the surface,
The antistatic surface protective film, wherein the release agent layer is formed of a resin composition containing a release agent containing dimethylpolysiloxane as a main component, a liquid silicone compound at 20°C, and an antistatic agent. The method of claim 4,
Monofunctional methacrylate monomers having a Tg of 0°C or higher of the homopolymer are n-butyl methacrylate, isobutyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, n-propyl methacrylate, Antistatic surface protective film, characterized in that at least one selected from the group of compounds consisting of isopropyl methacrylate, ethyl methacrylate, and methyl methacrylate. The method according to claim 4 or 5,
An antistatic surface protective film, wherein the antistatic agent in the release agent layer is an alkali metal salt. The method according to claim 4 or 5,
The (F) polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer constituting the polyalkylene glycol chain has an average repetition number of 3 to 14 alkylene oxide constituting the polyalkylene glycol chain,
The diester content in the polyalkylene glycol chain-containing mono(meth)acrylic acid ester monomer is 0.2% or less,
As the polyalkylene glycol chain-containing mono (meth) acrylic acid ester monomer, polyalkylene glycol mono (meth) acrylate, methoxy polyalkylene glycol (meth) acrylate, and ethoxy polyalkylene glycol (meth) acrylate Antistatic surface protective film, characterized in that at least one or more selected from the group consisting of. The method according to claim 4 or 5,
It is an antistatic surface protective film used as a surface protective film for polarizing plates,
In the use of the surface protective film for a polarizing plate, the protective layer of the polarizer of the polarizing plate used as an adherend is at least one selected from the group consisting of a TAC-based film, a PMMA-based film, and a PET-based film, and a protective layer of the polarizer of the polarizing plate Surface treatment applied to the surface of the antistatic surface protective film, characterized in that at least one selected from the group consisting of untreated, AG treatment, LR treatment, AR treatment, AG-LR treatment and AG-AR treatment. The method according to claim 4 or 5,
(B) The copolymerizable monomer containing a hydroxyl group is 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl Characterized in that at least one selected from the group consisting of (meth)acrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide Anti-static surface protective film. The method according to claim 4 or 5,
The (D) crosslinking retardant is a ketoenol tautomer compound,
Consisting of containing 0.1 to 300 parts by weight of the (D) crosslinking retardant relative to 100 parts by weight of the acrylic polymer,
The (E) crosslinking accelerator is at least one metal chelate compound selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound,
Consisting of containing 0.001 to 0.5 parts by weight of the (E) crosslinking accelerator based on 100 parts by weight of the acrylic polymer,
The antistatic surface protective film, characterized in that the weight part ratio of the (D) / (E) is 80 to 1000. The method according to claim 4 or 5,
Antistatic surface protection, characterized in that the pressure-sensitive adhesive composition contains 0.01 to 0.5 parts by weight of a polyether-modified siloxane compound having an HLB value of 6 to 12 and a weight average molecular weight of 10000 or less with respect to 100 parts by weight of the acrylic polymer. film. The method according to claim 4 or 5,
The antistatic surface protective film, wherein the silicone compound in the release agent layer is polyether-modified silicone. The method according to claim 4 or 5,
The antistatic agent in the release agent layer is a Li salt, and is at least one or more selected from the group consisting of LiTFSI, LiFSI, and LiTF.

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