TWI411654B - Antistatic acrylic pressure sensitive adhesive agent and protective film for optical element - Google Patents

Abstract

An antistatic acrylic pressure-sensitive adhesive characterized by comprising an acrylic copolymer (A) having a hydroxy group and an alkylene oxide chain in side chains, an ionic compound (B), a hardener (C), and an antioxidant (D). The antistatic pressure-sensitive adhesive is suitable for use as a pressure-sensitive adhesive for pressure-sensitive adhesive films for protecting the surface of an optical member. The pressure-sensitive adhesive solution before incorporation of the hardener has satisfactory storage stability. The antistatic pressure-sensitive adhesive has excellent transparency, is almost colorless, has excellent strippability after application, and is less apt to cause electrification upon stripping.

Description

Antistatic acrylic adhesive and protective film for optical member

The present invention relates to an antistatic adhesive and a protective film for an optical member carrying an adhesive layer formed of the above antistatic adhesive. More specifically, the present invention relates to an adhesive suitable for use in a surface protective film for mechanically and electrically protecting a surface of an adherend for a specified period of time. More specifically, the adhesive of the present invention is suitable for the formation of an adhesive film for surface protection of an optical member such as a liquid crystal panel, a plasma display, a polarizing plate, or a CRT (Brown Tube).

Conventionally, on the surface of various types of displays such as a word processor, a computer, a mobile phone, a television, or an optical component such as a polarizing plate or a laminate thereof, an electronic substrate or the like, the surface is generally protected and functionalized. Next, a transparent surface protective film (base film) such as polyethylene, polyester, or polypropylene is laminated through an adhesive layer.

Most of these surface protective adhesive films are peeled off after completion of surface protection work such as liquid crystal display. However, when the surface protective adhesive film is peeled off, there is a problem that static electricity is generated and the surrounding impurities are caught. Further, there is a problem that the liquid crystal or the electronic circuit is broken due to the peeling electrification which occurs when the adhesive film is peeled off from the surface.

Therefore, various proposals have been made as means for imparting antistatic properties to the surface protective adhesive film. Representative methods include, for example, the following three methods.

(1) a method of imparting antistatic property to a substrate film itself constituting the surface protective adhesive film; (2) between the substrate film constituting the surface protective adhesive film and the adhesive layer, or the substrate film is not laminated and adhered A method of providing a layer having antistatic properties on the surface of the layer; and (3) a method of imparting antistatic properties to the layer of the adhesive layer constituting the surface protective adhesive film.

(1) A method of obtaining a conductive base film by kneading an anionic compound such as an organic sulfonate group such as an organic sulfonate group, a conductive filler such as an organic sulfonate group, or a thermoplastic resin such as a polyester or a polyethylene which is a raw material of a base film. In this case, the transparency of the base film is lowered, and the film is colored.

However, during the application of the surface protective adhesive film to the adherend, it is also necessary to allow the surface protection appearance of the adherend to be inspected through the adhesive film. Therefore, the substrate film itself must have excellent transparency and no optical defects.

Therefore, in the case where the surface protective film using the base film containing the antistatic agent is attached to the adherend, the problem of the adherend is hard to be seen. Moreover, there is also a problem of high price of the base film.

The method of (2) further has various changes shown below (for example, Patent Documents 1 to 5).

(2-1) a method of vapor-depositing a metal compound on at least one side of the base film; and (2-2) a method of providing a layer containing the following various antistatic agents on at least one side of the base film: a 4-grade ammonium salt, having An anionic surfactant such as a long-chain alkyl compound of a sulfonate group; a thiophene derivative; a polymer having an ionized nitrogen element in the main chain; or a sulfonate-modified polystyrene.

However, since an anionic surfactant such as a long-chain alkyl compound having a sulfonate group belongs to a relatively low molecular weight, a part of the antistatic agent is moved into the antistatic coating film to be concentrated on the substrate film. The problem of shifting the interface to the opposite side of the substrate film, or the problem that the antistatic property is lowered with time.

Further, since the polymer having an ionized nitrogen element in the main chain or a sulfonate-based modified polyethylene or the like has a relatively high molecular weight, the above problem does not occur. However, in order to obtain good antistatic properties, it is necessary to add a large amount of an antistatic agent, and it is necessary to increase the film thickness of the antistatic layer, which is economically unfavorable. Further, there is a problem in that when a film scrap which is not a product (for example, a film end portion which is cut and removed in a manufacturing step) is recovered, a recycled material for film production is used, and when melt film forming, The antistatic agent component contained in the recycled material is thermally deteriorated, and the regenerated film is significantly colored, which is not practical (poorly recyclable). Therefore, there is a disadvantage that it is difficult to peel off between the films (blocking occurs), and the coating film is easily scratched, so that it is desired to solve the problem.

(3) The method of imparting antistatic property to a peeling interface where static electricity is generated, a method of forming an adhesive layer using a resin having antistatic property, and forming an adhesive layer by using an adhesive containing an antistatic agent Method (Patent Document 6).

In the former case, the antistatic property of the electrically conductive resin itself may be insufficient.

In the latter case, various antistatic agents and conductive powders such as carbon black can be used. However, in the case of using an adhesive containing a surfactant, in general, there is a tendency that the surfactant is concentrated on the surface of the adhesive layer (that is, the interface with the adherend), resulting in an extremely susceptible adhesive property. The effect of humidity. That is, the moisture causes the cohesive force of the adhesive layer to be lowered, and when the adhesive film is protected by the peeling surface, the adhesive layer is likely to partially remain on the adherend (so-called "retained"). On the other hand, when a conductive adhesive containing a conductive powder such as carbon black is used, the transparency of the adhesive layer and the surface protective adhesive film is lowered, or the film is colored.

Further, the use of an antistatic agent which is excellent in transparency and hardly causes coloring problems is also disclosed (for example, Patent Document 7).

However, the invention described in Patent Document 7 relates to an electrode gasket for use in attaching to a living body, and the conductive adhesive described in Patent Document 7 is not applicable to the electrode gasket. Surface protection adhesive film user.

Further, in the case where the adhesive layer which crosslinks the resin component in the adhesive via the curing agent is obtained as in the present invention, the shape is generally used for the purpose of ensuring the pot life (use time) of the adhesive. The hardener is first separated and the hardener is added before the adhesive is to be used. (Hereinafter, the adhesive solution containing no hardener is referred to as the "main agent".)

When the main component contains an alkylene oxide chain, the alkylene oxide chain is decomposed to generate a radical, so that the viscosity of the main agent itself rises with the passage of time, and the applicability of the adhesive is caused by the adhesive agent. Deterioration is considered a problem and is expected to be resolved.

Further, the adhesive containing the main agent and the curing agent is applied to various substrates such as a plastic film, dried, and cured to form an adhesive layer, and then attached to the adherend. In the case where the main component contains an alkylene oxide chain, the main agent reacts with the hardener to form an adhesive layer, and the decomposition of the alkylene oxide chain continues as time passes. If the decomposition of the alkylene oxide chain proceeds, there is also a problem that the conductivity is lowered.

(Patent Document 1) Japanese Patent Laid-Open Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Japanese Patent Publication No. 2002-275296 (Patent Document 5) Japanese Patent Laid-Open No. Hei 1-253482 (Patent Document 7) Japanese Patent No. 2718519

An object of the present invention is to provide an antistatic agent which is suitable as an adhesive for a surface protective adhesive film for optical members such as various displays and polarizing plates. The main agent has good storage stability, excellent transparency, almost no coloring phenomenon, and further It is excellent in peelability and has less peeling electrification at the time of peeling.

As a result of intensive review, the present inventors have found that an acrylic copolymer (A), an ionic compound (B), a hardener (C), and an antioxidant (D) having a hydroxyl group and an alkylene oxide chain in a side chain are contained. The present invention can be obtained by obtaining an antistatic adhesive having a good storage stability of a main agent and having moderate conductivity.

That is, the present invention relates to an antistatic acrylic adhesive characterized by comprising an acrylic copolymer (A), an ionic compound (B), and a hardener (C) having a hydroxyl group and an alkylene oxide chain in a side chain. And antioxidant (D).

In a preferred embodiment of the acrylic adhesive of the present invention, the alkylene oxide has a molar number of 4 to 16.

In another preferred embodiment of the acrylic adhesive of the present invention, the alkylene oxide chain is an ethylene oxide chain.

Further, in another preferred aspect of the acrylic pressure-sensitive adhesive of the present invention, the antioxidant (D) is at least one selected from the group consisting of a phenolic antioxidant, a phosphorous acid antioxidant, and a thioether antioxidant. .

Further, in another preferred embodiment of the acrylic pressure-sensitive adhesive of the present invention, the acrylic copolymer (A) has a weight average molecular weight of 50,000 to 1,000,000.

Further, in another preferred aspect of the invention, the ionic compound (B) is liquid or solid at normal temperature.

Further, in another preferred aspect of the invention, the ionic compound (B) is an inorganic salt of an alkali metal or an organic salt of an alkali metal.

Further, in another preferred embodiment of the acrylic pressure-sensitive adhesive of the present invention, the acrylic copolymer (E) having no alkylene oxide chain is further contained.

Further, in another preferred embodiment of the acrylic pressure-sensitive adhesive of the present invention, the low molecular weight acrylic copolymer (Al) having a weight average molecular weight of 50,000 to 200,000 in the side chain having a hydroxyl group and an alkylene oxide chain and A high molecular weight acrylic copolymer (E1) having an alkylene oxide chain having a weight average molecular weight of 200,000 to 1,000,000.

In another preferred embodiment of the acrylic pressure-sensitive adhesive of the present invention, the ionic compound (B) is contained in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the total of the acrylic copolymers (A) and (E).

Further, in another preferred embodiment of the acrylic pressure-sensitive adhesive of the present invention, the acrylic copolymer (A) is obtained by copolymerizing a monomer having an alkylene oxide chain to form an acrylic copolymer. When all the monomers of (A) are 100% by weight, the monomer having an alkylene oxide chain is 1 to 60% by weight.

Further, in another preferred embodiment of the acrylic pressure-sensitive adhesive of the present invention, the acrylic copolymer (A) is obtained by copolymerizing a monomer having an alkylene oxide chain to form an acrylic copolymer. When all the monomers (A) and (E) are 100% by weight, the monomer having an alkylene oxide chain is 1 to 60% by weight.

Further, in another preferred aspect of the acrylic adhesive of the present invention, the hardener (C) is a trifunctional isocyanate compound and/or a polyfunctional epoxy compound.

Further, the present invention relates to a protective film for an optical member characterized in that an adhesive layer formed of the above-mentioned antistatic acrylic adhesive is laminated on at least one side of a plastic film substrate.

According to the present invention, it is possible to obtain an antistatic adhesive which is excellent in storage stability of the main component, has an appropriate surface resistance value, and is excellent in transparency and removability.

The acrylic copolymer (A) used in the present invention may have a hydroxyl group and an alkylene oxide chain, and may be an acrylic monomer (a1) having a hydroxyl group and an acrylic monomer (a2) having an alkylene oxide chain. And if necessary, it can be synthesized with the other acrylic monomer (a3) which is copolymerized, that is, the acrylic monomer (a3) which does not have a hydroxyl group and an alkylene oxide chain.

The acrylic monomer (a1) having a hydroxyl group used in the present invention is an acrylic monomer (a1) having a hydroxyl group but no alkylene oxide chain, and specifically, 2-hydroxyethyl (methyl) Acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerin mono (meth) acrylate, and the like. In the present invention, 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate is preferred.

In the present invention, the purpose of using the hydroxyl group-containing acrylic monomer (a1) is to ensure adhesion to the adherend and to ensure removability. When the adhesive layer is formed, a curing agent (C) such as an isocyanate-based curing agent, which will be described later, is reacted with the hydroxyl groups to form a crosslinked structure, and other acrylic copolymers (A) to be described later can be suppressed. The molecular weight, thereby achieving a balance between adhesion and re-peelability.

Therefore, when only the acrylic copolymer (A) is used and the acrylic copolymer (E) is not used in combination, when all the monomers constituting the acrylic copolymer (A) are 100% by weight, acrylic acid having a hydroxyl group is used. The monomer (a1) is preferably 1 to 30% by weight. More preferably, it is 3 to 10% by weight.

Further, in the case where the acrylic copolymer (A) and the acrylic copolymer (E) are used in combination, when all the monomers of the structures (A) and (E) are 100% by weight, the acrylic monomer having a hydroxyl group (a1) is preferably 1 to 30% by weight. More preferably, it is 3 to 10% by weight.

In any of the above cases, when the acrylic monomer (a1) having a hydroxyl group is less than 1% by weight, the degree of crosslinking and the cohesive force of the adhesive layer are insufficient, the adhesive force is excessively increased, or the adhesive is likely to occur. Therefore, it is not good. If it exceeds 30% by weight, the degree of crosslinking is too high and lacks adhesion, which is not preferable.

Examples of the acrylic monomer (a2) having an alkylene oxide chain which can be used in the present invention include a monomer having an ethylene oxide chain, a monomer having an propylene oxide chain, and a single having the above two. body.

The molar number of the alkylene oxide chain (that is, the number of repeating units) is preferably from 3 to 20, preferably from 4 to 16, and more preferably from 6 to 12. When the molar number of addition of the alkylene oxide chain is too large, the treatment at the time of polymerization becomes complicated, the crystallinity of the copolymer obtained by the polymerization becomes high, or the formed adhesive layer tends to be solidified. On the other hand, if the molar number of addition of the alkylene oxide chain is too small, in order to obtain the desired conductivity, the monomer (a2) must be used in a large amount. In this case, it is formed as a by-product in the production step of the monomer (a2), and is affected by the bifunctional monomer contained in the monomer (a2) in the form of impurities, and tends to be easily gelled during polymerization.

Examples of the monomer having an ethylene oxide chain include alkoxy polyethylene glycol (meth) acrylate and alkoxy polyethylene glycol such as ethoxypolyethylene glycol (meth) acrylate ( Methyl) acrylate or polyethylene glycol (meth) acrylate, and the like.

Examples of the monomer having a propylene oxide chain include alkoxy polypropylene glycol (meth) acrylate such as methoxypolypropylene glycol (meth) acrylate or ethoxypolypropylene glycol (meth) acrylate or polycondensation. Propylene glycol (meth) acrylate and the like.

In the present invention, in consideration of compatibility with the ionic compound (B) described later, a monomer having an ethylene oxide chain is preferred. Further, from the viewpoint of not inhibiting the reactivity of the isocyanate-based crosslinking agent from the hydroxyl group derived from the monomer (a1) in the main component, the terminal hydroxyl group of the alkylene oxide chain is preferably an alkyl group-blocked alkoxy group. The acrylic monomer (a2) having an alkylene oxide chain used in the present invention is preferably methoxypolyethylene glycol (meth) acrylate or ethoxypolyethylene glycol (meth) acrylate.

The purpose of using the alkylene oxide chain-containing acrylic monomer (a2) in the present invention is to express the conductivity of the ionic compound (B) and the alkylene oxide chain. Therefore, the alkylene oxide chain is of great importance not only in the formation of a complex, but also as a mobile medium for the ionic compound (B). In other words, the conductivity in the present invention largely varies depending on the amount of the ionic compound (B) and the content of the monomer (a2) having an alkylene oxide chain.

Therefore, when only the acrylic copolymer (A) is used and the acrylic copolymer (E) is not used in combination, when all the monomers constituting the acrylic copolymer (A) are made 100% by weight, the alkylene oxide has an alkylene oxide. The chain acrylic monomer (a2) is preferably from 1 to 60% by weight. More preferably, it is 5 to 50% by weight, and particularly preferably 8 to 40% by weight.

Further, in the case where the acrylic copolymer (A) and the acrylic copolymer (E) are used in combination, when all of the monomers (A) and (E) are made 100% by weight, the acrylic acid having an alkylene oxide chain The monomer (a2) is preferably from 1 to 60% by weight. More preferably, it is 5 to 50% by weight, and particularly preferably 8 to 40% by weight.

When the amount of the acrylic monomer (a2) having an alkylene oxide is too small, the antistatic effect tends to be small. When the amount is too large, the crystallinity is high, and the high-speed peeling property and the antistatic property tend to be poor.

Examples of the monomer (a3) which can be copolymerized with the above acrylic monomer in the present invention include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. Butyl (meth)acrylate, amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate Ester, decyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, (a Tetracarbonate, heptyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, (a) Base) hexadecyl acrylate, eicosyl (meth) acrylate, stearyl (meth) acrylate, tetracosyl (meth) acrylate, (meth) acrylate, and the like. In the present invention, from the viewpoint of securing the adhesiveness, it is preferred to supply the acrylic monomer (a3) having 4 to 12 carbon atoms to the copolymerization. More preferred are butyl (meth)acrylate and 2-ethylhexyl (meth) acrylate.

These may be used singly or in combination of two or more kinds for the purpose of obtaining the preferable physical properties of the adhesive.

Weight average molecular weight of the acrylic copolymer (A1) having a hydroxyl group, the acrylic monomer (a2) having an alkylene oxide chain, and another monomer (a3) (Mw) is preferably 50,000 to 1,000,000, and a low molecular weight acrylic copolymer (A1) of 50,000 to 200,000 is more preferable.

As described in the prior art, for the adhesive for the optical member protective film, antistatic function, removability, and transparency are required. Therefore, from the viewpoint of antistatic function, the acrylic copolymer (A) preferably contains a large amount of an alkylene oxide chain.

In addition, the optical member is very thin and easily damaged, and is also relatively strong. As the protective film is attached to different adherends, the amount of peeling force required for the protective film and the adhesive is also different.

In other words, in the case where the optical member which is easily damaged is used as the adherend, the peeling force is preferably 200 g/25 mm or less, and more preferably 100 g/25 mm or less, in order not to damage the adherend when the film is protected after peeling and attaching.

On the other hand, in the case where a tough optical member is used as the adherend, the peeling force can be tolerated to 1000 g/25 mm.

Further, regardless of the type of adherend, it is always required that the adhesive does not remain in the adherend at the time of peeling.

The peeling force of the adhesive is greatly affected by the cohesive force of the main component constituting the adhesive itself and the crosslinking state of the main component and the hardener (C) to be described later. In general, the peeling force can be reduced by using a large amount of the hardener (C) for the main component. Further, in general, by increasing the molecular weight of the main component, the cohesive force of the main component itself can be increased.

In the adhesive of the present invention, when a low peeling force of 200 g/25 mm or less is required at the time of peeling, it is used in an amount of 1 to 30 parts by weight based on 100 parts by weight of the main component (that is, the acrylic copolymer (A)). The hardener (C) is preferably used in an amount of 2 to 20 parts by weight, more preferably 3 to 15 parts by weight. Further, from the viewpoint of exhibiting a low peeling force, it is preferred that the hardener (C) is more. However, if it is too much, the cross-linking is excessive, although it is smooth but it cannot be peeled off, and the rough is peeled off.

The acrylic monomer (a2) having an alkylene oxide chain used in the present invention can be easily copolymerized with other acrylic monomers (a1) and (a3), but has a large reverse chain transfer effect. Therefore, when the content of the alkylene oxide chain is increased from the viewpoint of improving conductivity, the molecular weight of the obtained acrylic copolymer (A) is liable to lower. When the molecular weight is lowered, the aggregation force of the acrylic copolymer (A) itself is liable to lower, and it is easy to leave an adhesive on the adherend during peeling.

However, if a relatively large amount of the hardener (C) is used for the acrylic copolymer (A) as described above in order to secure a low peeling force, a densely crosslinked adhesive layer can be obtained, even if a lower molecular weight acrylic resin is used. The copolymer (A1) does not leave an adhesive on the adherend during peeling.

Therefore, in the case where excellent electrical conductivity and low peeling force as described above are required, a weight average molecular weight (Mw) of 50,000 which is obtained by copolymerizing a large number of acrylic monomers (a2) having an alkylene oxide chain is used. The low molecular weight acrylic copolymer (A1) of ~200,000 is one of the preferable aspects as the acrylic copolymer (A).

Further, in the present invention, as the acrylic copolymer (A), a high molecular weight acrylic copolymer (A2) having a weight average molecular weight (Mw) of 200,000 to 1,000,000 may be used. By performing copolymerization while suppressing the chain transfer effect of the acrylic monomer (a2) having an alkylene oxide chain, an acrylic copolymer (A2) having a high molecular weight and excellent conductivity can be obtained.

For example, it can be obtained by setting a plurality of polymerization steps (multistage polymerization), reducing the amount of the initiator, or controlling the monomer concentration.

The multistage polymerization in the present invention means that the monomer is divided into a plurality of times for polymerization. For example, a case where all the monomers are charged in advance in a reaction container, or a monomer is added without dropping a monomer in the reaction container in advance, and all of the monomers are dropped while being polymerized; In the case where a part of the monomer is previously charged into the reaction vessel, and the remaining monomer is dropped while being polymerized, it is a two-stage polymerization. Further, the case where the above remaining monomer is divided into two stages and polymerized is referred to as a three-stage polymerization.

These polymerization methods can be selected according to the purpose of adjusting the molecular weight of the obtained polymer and the like.

In the present invention, more specifically, an acrylic monomer (a2) having an alkylene oxide chain for copolymerization or a monomer other than (a2) may be used in the initial stage of polymerization (reaction vessel). The polymerization is carried out as a main component, and after the polymerization is carried out to a certain extent, all or a majority of the acrylic monomer (a2) having an alkylene oxide chain is supplied to the polymerization to obtain a high molecular weight acrylic copolymer ( A2).

In the case of using such a so-called multistage polymerization method, when an amount of the acrylic monomer (a2) having an alkylene oxide chain is mainly polymerized, a polymerization initiator can be further used.

In addition, the high molecular weight acryl-based copolymer (A2) itself has a large cohesive force compared to the above-mentioned low molecular weight acryl-based copolymer (A1). Therefore, even if the amount of the curing agent (C) is reduced, it is difficult to remain at the time of peeling. gum. However, in the case where micro-adhesion of a peeling force of 100 g / 25 mm or less (preferably 50 g / 25 mm or less) is required, it is preferable to form a dense crosslinked structure in the adhesive layer. Therefore, the curing agent (C) is preferably the same as the above-mentioned low molecular weight acrylic copolymer (A1), and is preferably used in an amount of about 1 to 30 parts by weight based on 100 parts by weight of the high molecular weight acrylic copolymer (A2).

Further, in the present invention, an acrylic copolymer (E) having no alkylene oxide chain may be used in combination, and a high molecular weight acrylic acid having an alkylene oxide chain having a weight average molecular weight (Mw) of 200,000 or more and 1,000,000 or less may be used. The copolymer (E1) is used in combination with a low molecular weight acrylic copolymer (A1) having an alkylene oxide chain having a weight average molecular weight (Mw) of 50,000 to 200,000, and is also one of the aspects of the present invention.

When the high molecular weight acrylic copolymer (E1) is used in combination, the low molecular weight acrylic copolymer (A1) / high molecular weight acrylic copolymer (E1) = 5 to 80 / 20 to 95 (weight ratio) is preferred, 10~ 60/40~90 (weight ratio) is better.

The above-mentioned low molecular weight acrylic copolymer (A1) is excellent in electrical conductivity in most cases, but self-inhibited due to small cohesive force. From the viewpoint of preventing the glue remaining, the hardener (C) must be used in a large amount. The amount of the curing agent (C) can be reduced by using the high molecular weight acrylic copolymer (E1) in combination with such a low molecular weight acrylic copolymer (A1). For example, the curing agent (C) may be used in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the total of the low molecular weight acrylic copolymer (A1) and the high molecular weight acrylic copolymer (E1). The amount used. In the case where the peeling force of about 1000 g/25 mm can be tolerated at the time of peeling, by using the high molecular weight acrylic copolymer (E1) in combination and reducing the hardener (C), it is possible to respond to various grades of antistatic property and repeelability. Requirements.

In addition, when the amount of the low molecular weight acrylic copolymer (A1) and the high molecular weight acrylic copolymer (E1) is 100 parts by weight, the curing agent (C) is used in an amount of 1 to 30 parts by weight to obtain a low peeling force. Adhesive.

The acrylic copolymer (E) having no alkylene oxide chain used in the present invention can be obtained in the same manner as the acrylic monomer (A) except that the acrylic monomer having an alkylene oxide chain is not supplied to the polymerization.

In the present invention, in the case where the acrylic copolymer (A) and the acrylic copolymer (E) are used in combination, the two may be mixed after (A) and (E), respectively, or the acrylic may be obtained first. The copolymer (A) polymerizes the monomer constituting the acrylic copolymer (E) in the presence of the (A), or the acrylic copolymer (E) can be obtained first, and the presence of the (E) The monomer constituting the acrylic copolymer (A) is polymerized.

The ionic compound (B) used in the present invention may be any ionic compound which is liquid or solid at normal temperature. Here, the normal temperature means 25 ° C. Moreover, the ionic compound (B) used in the present invention may, for example, be an inorganic salt of an alkali metal or an organic salt of an alkali metal. Further, a surfactant or other such as ammonium chloride, aluminum chloride, copper chloride, iron chloride, ferrous chloride, ammonium sulfate or the like can be given. These may be used singly or in combination of two or more, and an alkali metal salt, a liquid ionic compound or a solid ionic compound is preferred, and an alkali metal salt or a liquid ionic compound is more preferable.

The alkali metal salt to be used in the present invention may be a metal salt composed of lithium, sodium, potassium or the like, and is composed of a cation portion formed of Li ⁺ , Na ⁺ and K ⁺ and various anion portions. Depending on the type of anion moiety, it can be classified into inorganic salts and organic salts.

Examples of the inorganic salts of the alkali metal include sodium chloride, potassium chloride, lithium chloride, lithium perchlorate (LiClO ₄ ), potassium chlorate, potassium nitrate, sodium nitrate, sodium carbonate, sodium sulfide sulfide, and LiBr. LiI, LiBF ₄ , LiPF ₆ , LiSCN, and the like. From the viewpoints of conductivity and safety, sodium chloride, potassium chloride, lithium perchlorate or the like is preferred.

Examples of the organic salt of an alkali metal include sodium acetate, sodium alginate, sodium lignosulfonate, sodium toluenesulfonate, LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, and Li (CF ₃ SO _{2 ).} )IN, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ )IN, Li(CF ₃ SO ₂ ) ₃ C, etc., with LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ )IN, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ )IN, Li(CF ₃ SO ₂ ) ₃ C, etc., preferably Li ( a fluorine-containing sulfonium imide lithium salt such as CF ₃ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ )IN, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ )IN, especially It is preferably a (perfluoroalkylsulfonyl) quinone imide lithium salt.

In the present invention, a liquid ionic compound as the ionic compound (B), which is a compound exhibiting liquid properties at normal temperature, is composed of a cationic component and an anionic component.

Examples of the cationic component of the ionic compound (B) of the present invention include a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, a cation having a pyrrole skeleton, an imidazolium cation, and a tetrahydropyrimidine. a phosphonium cation, a dihydropyrimidinium cation, a pyrazolinium cation, a tetraalkylammonium cation, a trialkyl phosphonium cation, a tetraalkyl phosphonium cation, or the like.

The anion component of the ionic compound (B) of the present invention is not particularly limited as long as it satisfies the conditions of the liquid ionic compound, and for example, Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl can be used. ₇ ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , NO ₃ ^- , CH ₃ COO ^- , CF ₃ COO ^- , CH ₃ SO ₃ ^- , CF ₃ SO ₃ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^- , ASF ₆ ^- , SbF ₆ ^- , NbF ₆ ^- , TaF ₆ ^- , F(HF) _n ^- , (CN) ₂ N ^- , C ₄ F ₉ SO ₃ ^- , ( C ₂ F ₅ SO ₂ ) ₂ N ^- , C ₃ F ₇ COO ^- , (CF ₃ SO ₂ )(CF ₃ CO)N ^- and the like. Among them, in particular, an anion component of a fluorine-containing atom is preferred because an ionic compound having a low melting point can be obtained.

Specific examples of the liquid ionic compound to be used in the present invention can be appropriately selected from the combination of the above cationic component and anionic component, and examples thereof include 1-butylpyridinium tetrafluoroborate and 1-butylpyridinium hexafluorophosphate. Phosphate, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis ( Trifluoromethanesulfonyl) quinone imine, 1-butyl-3-methylpyridinium bis(pentafluoroethanesulfonyl) quinone imine, 1-hexylpyridinium tetrafluoroborate, 2-methyl- 1-pyrroline tetrafluoroborate, 1-ethyl-2-phenylindole tetrafluoroborate, 1,2-dimethylindole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl -3-methylimidazolium heptafluoroacetate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium perfluorobutanesulfonate, 1- Ethyl-3-methylimidazolium Cyanamide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) quinone imine, 1-ethyl-3-methylimidazolium bis(pentafluoroethanesulfonyl) quinone imine 1-ethyl-3-methylimidazolium tris(trifluoromethanesulfonyl)methide, 1-butyl-3-methylimidazolium Tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium hexafluoroacetate Butyrate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazole Bis(trifluoromethanesulfonyl) quinone imine, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium Tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoro Borate, 1-octyl-3-methylimidazolium hexafluorophosphate , 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium bis(trifluoromethanesulfonyl) quinone imine, 1-methyl Pyrazolium tetrafluoroborate, 3-methylpyrazolium tetrafluoroborate, tetrahexylammonium bis(trifluoromethanesulfonyl) quinone imine, diallyldimethylammonium tetrafluoroborate, two Allyldimethylammonium tetrafluoromethanesulfonate, diallyldimethylammonium bis(trifluoromethanesulfonyl) quinone imine, diallyldimethylammonium bis(pentafluoroethanesulfonate) Iridium imine, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate, N,N-diethyl-N-methyl-N -(2-methoxyethyl)ammonium trifluoromethanesulfonate, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonate) Iridium imine, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(pentafluoroethanesulfonyl) quinone imine, epoxy propyl trimethyl Glycol trifluoromethanesulfonate, epoxypropyltrimethylammonium bis(trifluoromethanesulfonyl) quinone imine, epoxypropyltrimethylammonium bis(pentafluoroethanesulfonyl) quinone imine 1-butylpyridinium (trifluoromethanesulfonate) Trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonate) Trifluoroacetamide, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (trifluoromethanesulfonyl)trifluoroacetamide, diallyl Dimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, epoxypropyltrimethylamine (trifluoromethanesulfonyl) trifluoroacetamide, N,N-dimethyl-N- Ethyl-N-propylammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl-N-ethyl-N-butylammonium bis(trifluoromethanesulfonyl)pyrene Amine, N,N-dimethyl-N-ethyl-N-pentyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl-N-ethyl-N-hexylammonium Bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl-N-ethyl-N-heptyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl --N-ethyl-N-decyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl-N,N-dipropylammonium bis(trifluoromethanesulfonyl) Yttrium imine, N,N-dimethyl-N-propyl-N-butylammonium bis(trifluoromethanesulfonyl)pyrene Amine, N,N-dimethyl-N-propyl-N-pentyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl-N-propyl-N-hexylammonium Bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl-N-propyl-N-heptyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl --N-butyl-N-hexyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dimethyl-N-butyl-N-heptyl ammonium bis(trifluoromethanesulfonyl)醯imino, N,N-dimethyl-N-pentyl-N-hexyl ammonium bis(trifluoromethanesulfonyl) fluorene imine, N,N-dimethyl-N,N-dihexylammonium Bis(trifluoromethanesulfonyl) quinone imine, trimethylheptyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-diethyl-N-methyl-N-propyl ammonium Bis(trifluoromethanesulfonyl) quinone imine, N,N-diethyl-N-methyl-N-pentyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-diethyl --N-methyl-N-heptyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-diethyl-N-propyl-N-amyl ammonium bis(trifluoromethanesulfonate Iridium imine, triethylpropylammonium bis(trifluoromethanesulfonyl) quinone imine, triethylammonium bismuth (three Methanesulfonyl) quinone imine, triethylheptyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dipropyl-N-methyl-N-ethylammonium bis(trifluoro Methanesulfonyl) quinone imine, N,N-dipropyl-N-methyl-N-pentyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dipropyl-N- Butyl-N-hexyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dipropyl-N,N-dihexyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N, N-dibutyl-N-methyl-N-pentyl ammonium bis(trifluoromethanesulfonyl) quinone imine, N,N-dibutyl-N-methyl-N-hexyl ammonium bis(trifluoro Methanesulfonyl) quinone imine, trioctylmethylammonium bis(trifluoromethanesulfonyl) quinone imine, N-methyl-N-ethyl-N-propyl-N-amyl ammonium bis ( Trifluoromethanesulfonyl) quinone imine and the like.

The solid ionic compound which can be used as the ionic compound (B) in the present invention means a combination of the above cationic component and anionic component, and exhibits a solid property at normal temperature.

The surfactant which can be used as the ionic compound (B) in the present invention may, for example, be a cationic surfactant or an anionic surfactant.

The cationic surfactant may, for example, be an alkyltrimethylammonium salt, a acyloyl guanamine propyltrimethylammonium methoxide, an alkylbenzylmethylammonium salt or a guanylcholine chloride. a styrene copolymer having a 4-stage ammonium group such as a (meth) acrylate copolymer having a 4-stage ammonium group such as polydimethylaminoethyl methacrylate or a polyvinyl benzyl trimethyl ammonium chloride; A diallylamino group copolymer having a 4-stage ammonium group such as polydiallyldimethylammonium chloride or the like. These compounds may be used singly or in combination of two or more.

Examples of the anionic surfactant include alkylsulfonates, alkylbenzenesulfonates, alkylsulfate salts, alkylethoxysulfate salts, alkyl phosphate salts, and sulfonic acid group-containing styrene copolymers. Fit and so on. These compounds may be used singly or in combination of two or more.

Further, the total amount of the ionic compound (B) is 100 parts by weight based on 100 parts by weight of the acrylic copolymer (A) or, in the case where the acrylic copolymer (E) is used in combination, the total amount of the conjugated compound (B) is 0.1 to 50 parts by weight is preferred. More preferably, it is 1 to 30 parts by weight. When the amount is less than 0.1 part by weight, sufficient ionic conductivity cannot be obtained. When more than 50 parts by weight of the ionic compound (B) is contained, the effect of improving the conductivity is hardly expected, and the adhesive property is likely to be lowered and the cause is lowered. The decrease in compatibility with the resin causes whitening of the coating film, which is not preferable.

In the time stability of an adhesive film (that is, a protective film for an optical member) comprising an antistatic acrylic adhesive, the amount of the ionic compound (B) and the acrylic copolymer (A) are greatly affected. The amount of alkylene oxide chain contained in it is affected.

When the amount of the alkylene oxide chain is large, the ionic compound (B) can be efficiently formed into a complex. However, when the amount of the alkylene oxide chain is small and the amount of the ionic compound is large, an excessive amount of the complex can not be formed. The ionic compound is transferred to the surface of the adhesive layer, which easily causes the above-mentioned whitening phenomenon. Moreover, the surface resistance value over time also tends to rise.

From such a viewpoint, it is preferable to increase the amount of the alkylene oxide chain contained in the adhesive layer as much as possible, and to add a minimum amount of the ionic compound (B) which exhibits the required conductivity.

In the antistatic acrylic pressure-sensitive adhesive of the present invention, in order to enhance the cohesive force and the degree of crosslinking, a curing agent (C) can be suitably used.

The curing agent (C) of the present invention preferably has two or more functional groups reactive with a functional group such as a hydroxyl group contained in the acrylic copolymers (A) and (E) in one molecule. For example, a known trifunctional isocyanate compound or a known polyfunctional epoxy compound can be suitably used. These can also be used in combination.

As a known trifunctional isocyanate compound, a so-called addition product obtained by modifying a known diisocyanate compound with a trifunctional polyol component, a burrete body obtained by reacting a diisocyanate compound with water, and a molecule of 3 molecules can be used. A trimer (trimeric isocyanate) having a trimeric isocyanate ring formed of a diisocyanate compound.

Examples of the known diisocyanate compound include aromatic diisocyanate, aliphatic diisocyanate, aromatic aliphatic diisocyanate, and alicyclic diisocyanate.

Examples of the aromatic diisocyanate include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, and 4,4'-diphenyl diiso isocyanate. Methyl cyanate, 2,4-methylphenylene diisocyanate, 2,6-methylphenylene diisocyanate, 4,4'-tolidine diisocyanate, diansamine diisocyanate, 4,4'- Diphenyl ether diisocyanate or the like.

Examples of the aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propyl propyl diisocyanate, and 2,3-. Butyl diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like.

Examples of the aromatic aliphatic diisocyanate include ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, and ω,ω'-two. Isocyanate-1,4-diethylbenzene, 1,4-tetramethylstilbene diisocyanate, 1,3-tetramethylstilbene diisocyanate, and the like.

Examples of the alicyclic diisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-diisocyanate cyclopentyl ester, and 1,3-diisocyanate ring. Hexyl ester, cyclohexyl 1,4-diisocyanate, cyclohexyl methyl-2,4-diisocyanate, cyclohexyl methyl-2,6-diisocyanate, 4,4'- Methylene bis(cyclohexyl isocyanate), 1,4-bis(isocyanatemethyl)cyclohexane, 1,4-bis(isocyanatemethyl)cyclohexane, and the like.

Used in the diisocyanate compound of the present invention to use methyl 4,4'-diphenyldiisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl Isocyanate (also known as "isophorone diisocyanate") is preferred.

The well-known polyfunctional epoxy compound is not particularly limited as long as it is a compound having a plurality of epoxy groups in the molecule. Specific examples of the polyfunctional epoxy compound include ethylene glycol diepoxypropyl ether, polyethylene glycol diepoxypropyl ether, 1,6-hexanediol diepoxypropyl ether, and double Phenol A. Epichlorohydrin type epoxy resin, N, N, N', N'-tetraepoxypropyl-m-xylylenediamine, 1,3-bis(N,N-diepoxypropylaminomethyl) Cyclohexane, N,N-diepoxypropylaniline, N,N-diepoxypropyltoluamide, and the like.

As the curing agent (C), a trifunctional isocyanate compound and a polyfunctional epoxy compound may be used alone or in combination. When it is used for applications where flexibility is emphasized, it is preferred to use a trifunctional isocyanate compound, and in the case where heat resistance is required, it is preferred to use a polyfunctional epoxy compound.

In the case of a low peeling force of 200 g/25 mm or less (preferably 100 g/25 mm) or less as described above, the hardener (C) is used in an amount of 1 to 30 by weight with respect to 100 parts by weight of the acrylic copolymer (A). Preferably, it is preferably 2 to 20 parts by weight, more preferably 3 to 15 parts by weight.

Further, in the case of using a polyfunctional epoxy compound, in order to act as a crosslinking agent more effectively, it is preferred to contain acrylic acid or methacrylic acid in the acrylic copolymer (A). The content thereof is preferably 0.5 to 5% by weight in the total acrylic monomer. If it is less than 0.5%, it is not sufficient to act as a crosslinking agent. If it exceeds 5%, the pot life after the addition of the curing agent (C) is likely to be short, which is not preferable.

In the antistatic adhesive of the present invention, it is important to use an antioxidant (D).

One of the purposes is to suppress the increase in the viscosity of the main agent over time. Another object is to suppress the conductivity of the adhesive layer from decreasing as time passes after the main agent reacts with the hardener.

In the acrylic copolymer (A) of the present invention, a monomer having a large amount of alkylene oxide chains is used, and in a severe environment (for example, air temperature, room temperature of 50 ° C or higher), the ester bond portion which is unstable to heat is decomposed. , generating free radicals. Due to the influence, the residual monomer remaining in the main component when the acrylic copolymer (A) or the acrylic copolymer (E) is obtained may be polymerized over time to cause the main agent to be thickened. In the present invention, by using the antioxidant (D), the decomposition of the ester bond of the alkylene oxide chain can be suppressed, and the increase in the viscosity of the main agent with time can be suppressed. Further, in the present invention, by using the antioxidant (D), after the reaction between the main component and the curing agent, decomposition of the ether bond of the alkylene oxide chain can be suppressed, and the decrease in the electrical conductivity of the adhesive layer can be suppressed with time.

The amount of the antioxidant (D) to be used is preferably 0.01 to 10.0 parts by weight, more preferably 0.1 to 3.0 parts by weight, per 100 parts by weight of the acrylic copolymer (A). When the amount is less than 0.01 parts by weight, the effect of suppressing the increase in the viscosity of the main agent is insufficient, and if it is more than 10.0 parts by weight, the adherend may be contaminated by the antioxidant component.

As the antioxidant (D) used in the present invention, a known antioxidant can be used.

Examples of the known antioxidant (D) include a phenol-based antioxidant, a phosphite-based antioxidant, and a thioether-based antioxidant. These may be used alone or in combination as many may be used. In the present invention, a phenol-based antioxidant is preferred, and particularly a hindered phenol-based antioxidant is preferred from the viewpoints of heat resistance, weather resistance, and compatibility.

The phenolic antioxidant may, for example, be a compound of the following CAS number. 27676-62-6, 1843-03-4, 85-60-9, 2085-79-3, 6683-19-8, 36443-68-2, 90498-90-1 (Adekastub A0-80), 1709- 70-2, 41484-35-9, 23128-74-7, 125643-61-0, 134701-20-5, 976-56-7, 65140-91-2, 110553-27-0, 35074-77- 2, 40601-76-1, 68411-46-1, 991-84-4 and so on.

Examples of the phosphite-based antioxidant include compounds of the following CAS numbers. 52664-24-1, 3806-34-6, 26741-53-7, 80693-00-1, 126050-54-2 (Adekastub HP-10), 31570-04-4, 13003-12-8, 26523- 78-4 and so on.

Examples of the thioether-based antioxidant include [66534-05-2, 71982-66-6] (Adekastub A0-23), 29598-76-3, and 10595-72-9.

In the antistatic adhesive of the present invention, other resins such as an acrylic resin, a polyester resin, an amine resin, an epoxy resin, or a polyurethane resin may be used in combination as needed. Moreover, depending on the use, the following additives may be formulated: an adhesive-imparting agent, a filler such as talc, calcium carbonate, or titanium oxide; a coloring agent; a UV absorber; an antifoaming agent; a light stabilizer.

By using the antistatic adhesive of the present invention, an adhesive sheet formed by laminating an adhesive layer formed of the adhesive with a plastic film, paper, cloth, foam or the like can be obtained, and the adhesive layer can be used. The surface is covered with a release sheet.

Adhesive sheets can be coated or impregnated with various substrates and dried. Hardened. Alternatively, an adhesive may be applied to the release sheet, dried, and various substrates may be laminated on the surface of the simultaneously formed adhesive layer to make the hydroxyl group in the adhesive and the isocyanate group in the hardener (C), or an adhesive. The carboxyl group in the reaction is obtained by reacting an epoxy group in the hardener (C).

The adhesive of the present invention is preferably applied to a transparent plastic film as a substrate, whereby it can be suitably used for producing a surface protective adhesive film for an optical member.

Examples of the plastic film include a polyvinyl chloride film, a polyethylene film, a polyethylene terephthalate (PET) film, a polyurethane film, a nylon film, a treated polyolefin film, and an untreated polyolefin film. Wait.

The antistatic adhesive of the present invention is preferably coated on a substrate or the like to be dried. When hardened, it becomes a thickness of about 2 to 200 μm. If it is less than 2 μm, the ion conductivity is lacking, and if it exceeds 200 μm, the production and handling of the adhesive film become difficult.

Thus, an antistatic adhesive film having a surface resistance value of 10 ^{1 1} Ω/□ or less of the adhesive layer can be obtained.

By using the antistatic adhesive of the present invention, various aspects of the antistatic adhesive film can be obtained in consideration of the use, the required properties, and the like.

For example, an antistatic adhesive film for a protective film for a polarizing plate will be described with reference to the drawings.

1 is an antistatic adhesive film of the present invention comprising a PET (polyethylene terephthalate) film substrate 1 and an antistatic acrylic adhesive layer 2 supported on one surface thereof, using antistatic A schematic cross-sectional view of the state in which the acrylic pressure-sensitive adhesive layer 2 is attached to the polarizing plate 3.

2 shows an antistatic adhesive film of the present invention in which an antistatic acrylic adhesive layer 2 is provided on both sides of a PET film substrate 1, and is attached to the polarizing plate 3 by an antistatic acrylic adhesive layer 2. A schematic cross-sectional view of the state.

3 is an antistatic adhesive film of the present invention in which an antistatic coating agent layer 4 is provided on one surface of a PET film substrate 1 and an antistatic acrylic adhesive layer 2 is further carried thereon. A schematic cross-sectional view of the state in which the antistatic acrylic pressure-sensitive adhesive layer 2 is attached to the polarizing plate 3.

4 is an antistatic adhesive film of the present invention in which an antistatic acrylic adhesive layer 2 is provided on one surface of a PET film substrate 1, and an antistatic coating agent layer 4 is provided on the reverse side surface thereof. A schematic cross-sectional view of the state in which the antistatic acrylic pressure-sensitive adhesive layer 2 is attached to the polarizing plate 3.

In the case where the adhesive of the present invention is used for a film for surface protection of an optical member or an electronic member, an antistatic coating agent layer may be provided as shown in FIGS. 3 and 4 in order to further reduce the peeling charge amount.

Further, in the use of the plastic film in a functional manner, as shown in Fig. 2, an antistatic acrylic adhesive layer may be provided on both surfaces of the base film to further bond an antistatic acrylic adhesive layer. Functional film (for example, retardation film, optical compensation film, light diffusion film, electromagnetic wave shielding film, etc.).

Considering the workability and production cost, the best aspect is shown in Figure 1.

As shown in FIG. 3 and FIG. 4, antistatic property is not provided on the opposite side (top coating) between the adhesive layer and the plastic film substrate, or on the side of the adhesive layer not belonging to the plastic film substrate (top coating). Examples of the antistatic agent used in the case of the coating layer include a metal filler, a quaternary ammonium salt derivative, a surfactant, and a conductive resin.

Examples of the metal filler include metal oxides such as tin oxide, zinc oxide, iron oxide, and cerium oxide; carbon; metals such as silver and copper. When considering the transparency of a coating film, tin oxide, cerium oxide, etc. are preferable.

As the 4-grade ammonium salt derivative, a polymer having a (meth) acrylate monomer having a quaternary ammonium salt or a copolymer with another (meth) acrylate monomer can be used.

The antistatic coating layer preferably has a thickness of 0.1 to 50 μm, more preferably 1 μm to 20 μm. If it is less than 0.1 μm, the antistatic performance may not be sufficiently exhibited. If it exceeds 50 μm, problems such as cost and coatability may occur.

(Example) (Synthesis Example 1)

The acrylic copolymer (A) composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

In other words, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 46% by weight of 2EHA was added to the reaction tank [indicating 46% of the "68"% by weight shown in Table 1). ; the same as the following], 50% by weight of BA, 50% by weight of 2HEA, the total amount of AM90G, and an appropriate amount of ethyl acetate as a solvent, azobisisobutyronitrile as a starter, and an appropriate amount of residual monomer The total amount, ethyl acetate, azobisisobutyronitrile and the mixed solution were dropped over about 1 hour, and polymerized at about 80 ° C for 5 hours under a nitrogen atmosphere. After completion of the reaction, it was cooled and diluted with ethyl acetate. The reaction solution has a solid content of 40% and a viscosity of 1300 mPa. s, Mw (weight average molecular weight) 310,000.

(Synthesis Example 2)

The acrylic copolymer (A) composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

In other words, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 44% by weight of 2EHA, 50% by weight of 2HEA, and the total amount of M40G were placed in the reaction tank, and an appropriate amount was used as a solvent. Ethyl acetate, azobisisobutyronitrile as a starter, adding a suitable amount of residual monomer, ethyl acetate, azobisisobutyronitrile and mixing the solution takes about 1 hour to drip, under nitrogen atmosphere Polymerization was carried out at 80 ° C for 5 hours. After completion of the reaction, it was cooled and diluted with ethyl acetate. The reaction solution has a solid content of 41% and a viscosity of 1200 mPa. s, Mw (weight average molecular weight) 350,000.

(Synthesis Example 3)

The acrylic copolymer (A) composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

In other words, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 35 wt% of 2EHA, 30% by weight of BA, and 30% by weight of 2HEA, and an appropriate amount were placed in the reaction vessel. Ethyl acetate as a solvent and azobisisobutyronitrile as a starter, followed by adding an appropriate amount of 42% by weight of 2EHA, 40% by weight of BA, 40% by weight of 2HEA, 30% by weight of M90G, and ethyl acetate The solution of the ester, azobisisobutyronitrile and the mixture was dropped over about 1 hour, and polymerized at about 80 ° C for 1 hour under a nitrogen atmosphere.

Thereafter, a solution in which an appropriate amount of residual monomer, ethyl acetate, azobisisobutyronitrile was added and mixed was dropped over about 1 hour, and polymerization was carried out at about 80 ° C for 5 hours under a nitrogen atmosphere. After completion of the reaction, it was cooled and diluted with ethyl acetate and toluene. The reaction solution has a solid content of 40% and a viscosity of 1500 mPa. s, Mw (weight average molecular weight) 330,000.

(Synthesis Example 4)

The acrylic copolymer (A) composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

In other words, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 40% by weight of 2EHA, 30% by weight of BA, and 30% by weight of 2HEA, and an appropriate amount were placed in the reaction vessel. Ethyl acetate as a solvent and azobisisobutyronitrile as a starter, followed by adding an appropriate amount of 46% by weight of 2EHA, 40% by weight of BA, 40% by weight of 2HEA, 20% by weight of M90G, and ethyl acetate The solution of the ester, azobisisobutyronitrile and the mixture was dropped over about 1 hour, and polymerized at about 80 ° C for 1 hour under a nitrogen atmosphere.

Thereafter, a solution in which an appropriate amount of residual monomer, ethyl acetate, azobisisobutyronitrile was added and mixed was dropped over about 1 hour, and polymerization was carried out at about 80 ° C for 5 hours under a nitrogen atmosphere. After completion of the reaction, it was cooled and diluted with ethyl acetate and toluene. The reaction solution has a solid content of 40% and a viscosity of 3700 mPa. s, Mw (weight average molecular weight) 250,000.

(Synthesis Example 5)

The acrylic copolymer (A) composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

In other words, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 74% by weight of 2EHA, 50% by weight of 2HEA, and an appropriate amount of ethyl acetate as a solvent were placed in the reaction vessel. As the initiator, azobisisobutyronitrile, adding a suitable amount of the remaining monomer, ethyl acetate, toluene, azobisisobutyronitrile and mixing the solution takes about 1 hour to drip, about 80 ° C under nitrogen atmosphere Polymerization for 5 hours. After completion of the reaction, it was cooled and diluted with toluene. The reaction solution has a solid content of 41% and a viscosity of 1000 mPa. s, Mw (weight average molecular weight) 110,000.

(Synthesis Example 6)

The acrylic copolymer (A) composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

Specifically, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 44% by weight of 2EHA, 50% by weight of BA, 50% by weight of 2HEA, and 50% of AA were placed in the reaction vessel. % by weight, the total amount of M40G, and an appropriate amount of ethyl acetate as a solvent, azobisisobutyronitrile as a starter, and a suitable amount of residual monomer, ethyl acetate, azobisisobutyronitrile and a mixed solution It took about 1 hour to drip and was polymerized at about 80 ° C for 5 hours under a nitrogen atmosphere. After completion of the reaction, it was cooled and diluted with ethyl acetate. The reaction solution has a solid content of 40% and a viscosity of 2000 mPa. s, Mw (weight average molecular weight) 320,000.

(Synthesis Example 7)

The acrylic copolymer (A) composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

In other words, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 88% by weight of 2EHA, 50% by weight of 2HEA, and an appropriate amount of ethyl acetate as a solvent were placed in the reaction vessel. As the initiator, azobisisobutyronitrile, adding a suitable amount of the remaining monomer, ethyl acetate, toluene, azobisisobutyronitrile and mixing the solution takes about 1 hour to drip, about 80 ° C under nitrogen atmosphere Polymerization for 5 hours. After completion of the reaction, it was cooled and diluted with toluene. The reaction solution has a solid content of 40% and a viscosity of 400 mPa. s, Mw (weight average molecular weight) 105,000.

(Synthesis Example 8)

The acrylic copolymer (E) composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

In other words, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 50% by weight of 2EHA, 50% by weight of BA, and 50% by weight of 2HEA, and an appropriate amount were placed in the reaction vessel. Ethyl acetate as a solvent, azobisisobutyronitrile as a starter, and a solution in which an appropriate amount of residual monomer, ethyl acetate, azobisisobutyronitrile is added and mixed, and it takes about 1 hour to drip under nitrogen atmosphere Polymerization was carried out at about 80 ° C for 5 hours. After completion of the reaction, it was cooled and diluted with ethyl acetate. The reaction solution has a solid content of 41% and a viscosity of 1700 mPa. s, Mw (weight average molecular weight) 400,000.

(Synthesis Example 9)

An acrylic copolymer composed of a monomer having a composition ratio shown in Table 1 and containing no hydroxyl group was obtained by the following method.

Specifically, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and 35 wt% of 2EHA, 30% by weight of BA, and an appropriate amount of ethyl acetate as a solvent were placed in the reaction vessel. As the initiator, azobisisobutyronitrile, followed by adding an appropriate amount of 42% by weight of 2EHA, 40% by weight of BA, 30% by weight of M90G, ethyl acetate, azobisisobutyronitrile and mixed solution It took about 1 hour to drip and was polymerized at about 80 ° C for 1 hour under a nitrogen atmosphere.

Thereafter, a solution in which an appropriate amount of residual monomer, ethyl acetate, azobisisobutyronitrile was added and mixed was dropped over about 1 hour, and polymerization was carried out at about 80 ° C for 5 hours under a nitrogen atmosphere. After completion of the reaction, it was cooled and diluted with ethyl acetate and toluene. The reaction solution has a solid content of 40% and a viscosity of 1300 mPa. s, Mw (weight average molecular weight) 350,000.

(Synthesis Example 10)

The hydroxy group-free acrylic copolymer composed of the monomer having the composition ratio shown in Table 1 was obtained by the following method.

In other words, a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel was used, and all the monomers, benzene as a solvent, and azobisisobutyronitrile as a starter were charged into the reaction vessel. The polymerization was carried out at about 80 ° C for 5 hours under a nitrogen atmosphere to obtain a reaction solution of 40% solid content.

2EHA: 2-ethylhexyl acrylate BA: butyl acrylate 2HEA: 2-hydroxyethyl acrylate AA: acrylic acid AM90G: methoxy polyethylene glycol acrylate (ethylene oxide 9 mol) M230G: methoxy poly Glycol methacrylate (ethylene oxide 23 mol) M90G: methoxy polyethylene glycol methacrylate (ethylene oxide 9 mol) M40G: methoxy polyethylene glycol methacrylate (epoxy B) Alkane 4mol)

[Example 1]

3 g of lithium perchlorate and "Adekastub AO-80" (antioxidant: 3,9-bis[1,1-dimethyl-2-[] were prepared for 40 g of the solid content of the acrylic resin solution obtained in Synthesis Example 1. --(3-Tertibutyl-4-hydroxy-5-methylphenyl)propanyloxy]ethyl]2,4,8,10-tetra-sentyloxy[5,5]Eleven 0.2 g of alkane; manufactured by Asahi Kasei Co., Ltd., and 10 g of a 37% ethyl acetate solution of methyl phenyl diisocyanate trimethylolpropane adduct as a curing agent to prepare an adhesive.

The obtained adhesive was applied to a release paper, and the dried coating film was 20 μm. After drying at 100 ° C for 2 minutes, a polyethylene terephthalate film (thickness 38 μm) was laminated and simultaneously formed. The adhesive layer was passed through this state for 2 days to obtain a test adhesive tape.

Using the test adhesive tape, the adhesion, surface resistance value, re-peelability, and transparency were evaluated by the methods shown below. In addition, the storage stability of the main agent of the adhesive was evaluated.

<adhesion>

The release paper of the test adhesive tape was peeled off, and the exposed adhesive layer was adhered to a glass plate having a thickness of 2 mm at 23 ° C to 50% RH, and subjected to roll pressing in accordance with JIS Z-0237. After 24 hours of pressing, the peel strength (180 degree peeling, stretching speed 300 mm/min; unit g/25 mm width) was measured by a Schopper type peeling tester.

<surface resistance value>

The release paper of the test adhesive tape was peeled off, and the surface resistance value (Ω/□) of the surface of the exposed adhesive layer was measured using a surface resistance value measuring device (manufactured by Mitsubishi Chemical Corporation).

<repeelability>

The release tape of the test adhesive tape was peeled off, and the exposed adhesive layer was adhered to the glass plate, and then left at 60 ° C - 95% RH for 24 hours, cooled to 23 ° C - 50% RH, and then from the glass plate. Peeling was performed to visually evaluate the residual property to the glass plate. Specifically, the state after peeling was evaluated in the following four stages.

No glue is transferred to the adherend ◎ Only a small amount of glue is transferred to the adherend ○ Some of the glue is transferred to the adherend △ All the glue is transferred to the adherend ╳

<Transparency>

The release tape of the test adhesive tape was peeled off, the exposed adhesive layer was adhered to the glass plate, and left at 60 ° C - 95% RH for 24 hours, cooled to 23 ° C - 50% RH, and visually evaluated. .

Colorless and transparent ◎ Only a small amount of fogging ○ Can see white turbidity, agglomerate △ opaque ╳

<Storage stability of the main agent>

The main agent of the adhesive (when no hardener was added to the formulation) was placed in a closed container, and the rate of increase in viscosity after one month in an oven at 50 ° C was measured.

Viscosity increase rate is less than 10% ◎ Viscosity increase rate is 10% or more and less than 20% ○ Viscosity increase rate is 20% or more and less than 50% △ Viscosity increase rate is 50% or more or gelation occurs ╳

[Examples 2, 3, 5]

An adhesive was prepared in the same manner as in Example 1 except that the acrylic resin obtained in Synthesis Examples 2, 3, and 5 was used, and lithium perchlorate was used in an amount of 5 g, and evaluated in the same manner as in Example 1.

[Example 4]

An adhesive was prepared in the same manner as in Example 1 except that the acrylic resin obtained in Synthesis Example 4 was used, and lithium perchlorate was used in an amount of 3 g, and evaluated in the same manner as in Example 1.

[Embodiment 6]

The same procedure as in Example 1 was carried out except that the acrylic resin obtained in Synthesis Example 6 was used as a curing agent using 3 g of a N, N, N', N'-tetraepoxypropyl-m-xylylenediamine 5% toluene solution. The adhesive was obtained and evaluated in the same manner as in Example 1.

[Embodiment 7]

50 g of the acrylic resin solution obtained in Synthesis Example 5 and 50 g of the acrylic resin solution obtained in Synthesis Example 8 were mixed in the same manner as in Example 1 except that 5 g of perchlorate was used, and the evaluation was carried out in the same manner as in Example 1.

[Embodiment 8]

An adhesive was prepared in the same manner as in Example 1 except that the acrylic resin obtained in Synthesis Example 7 was used, and lithium perchlorate was used in an amount of 1 g, and evaluated in the same manner as in Example 1.

[Embodiment 9]

An adhesive was prepared in the same manner as in Example 1 except that the acrylic resin obtained in Synthesis Example 7 was used, and lithium perchlorate was used in an amount of 3 g, and evaluated in the same manner as in Example 1.

[Examples 10, 11]

The same procedure as in Example 1 was carried out except that the acrylic resin obtained in Synthesis Examples 5 and 7 was used, and lithium perchlorate was used in an amount of 1 g, and the test adhesive tape was obtained at room temperature for 7 days.

[Embodiment 12]

The acrylic resin obtained in Synthesis Example 7 was used in the same manner as in Example 1 except that lithium perchlorate was used in an amount of 1 g and a test adhesive tape was obtained by heating at 50 ° C for 30 days.

[Example 13]

An adhesive was prepared in the same manner as in Example 8 except that 0.5 g of CIL-314 (manufactured by Carlit Corporation, Japan: liquid ionic compound; pyridinium derivative) was used instead of 1 g of lithium perchlorate, and the evaluation was carried out in the same manner as in Example 1.

[Embodiment 14]

An adhesive was prepared in the same manner as in Example 8 except that 0.3 g of lithium bis(pentafluoroethanesulfonyl) ruthenium was used instead of 1 g of lithium perchlorate, and the evaluation was carried out in the same manner as in Example 1.

[Example 15]

An adhesive was prepared in the same manner as in Example 8 except that 1 g of PEL-20A (manufactured by Carlit Corporation, Japan: lithium perchlorate/polyether polyol) was used instead of 1 g of lithium perchlorate, and the evaluation was carried out in the same manner as in Example 1.

[Example 16]

An adhesive was prepared in the same manner as in Example 8 except that 1 g of Elegan C-114 (manufactured by Nippon Oil Co., Ltd.: cationic surfactant) was used instead of 1 g of lithium perchlorate, and the evaluation was carried out in the same manner as in Example 1.

[Example 17]

An adhesive was prepared in the same manner as in Example 8 except that 1 g of KS-1262 (manufactured by Kao Corporation: anionic surfactant) was used instead of 1 g of lithium perchlorate, and the evaluation was carried out in the same manner as in Example 1.

[Embodiment 18]

Other than 0.1 g of Elegan C-114 (manufactured by Nippon Oil Co., Ltd.: cationic surfactant) and 0.1 g of PEL-20A (manufactured by Japan Carlit Co., Ltd.: lithium perchlorate/polyether polyol) were used in place of 1 g of lithium perchlorate. An adhesive was prepared in the same manner as in Example 8 and evaluated in the same manner as in Example 1.

[Embodiment 19]

An adhesive was prepared in the same manner as in Example 8 except that 0.3 g of Adekastub HP-10 (manufactured by Asahi Kasei Co., Ltd.: phosphite antioxidant) was used instead of 0.2 g of "Adekastub AO-80". Evaluation.

[Example 20]

An adhesive was prepared in the same manner as in Example 8 except that 0.2 g of Adekastub AO-23 (Adhesive AO-80) was used instead of 0.2 g of Adekastub AO-80, and the evaluation was carried out in the same manner as in Example 1. .

[Example 21]

An adhesive was prepared in the same manner as in Example 8 except that 0.2 g of Tinuvin T-123 (manufactured by Ciba Specialty Chemical Co., Ltd.: hindered amine-based antioxidant) was used instead of 0.2 g of "Adekastub AO-80", and the evaluation was carried out in the same manner as in Example 1. .

[Example 22]

An adhesive was prepared in the same manner as in Example 8 except that 0.2 g of Irgans 1010 (manufactured by Ciba Specialty Chemical Co., Ltd.: hindered phenol-based antioxidant) was used instead of 0.2 g of "Adekastub AO-80", and the evaluation was carried out in the same manner as in Example 1.

[Example 23]

An adhesive was prepared in the same manner as in Example 8 except that 1 g of ILA2-2 (manufactured by Kwong Wing Chemical Co., Ltd. solid ionic compound) was used instead of 1 g of lithium perchlorate, and the evaluation was carried out in the same manner as in Example 1.

[Comparative Examples 1, 4]

An adhesive was prepared in the same manner as in Example 1 except that each of the acrylic resins obtained in Synthesis Examples 8 and 3 and lithium perchlorate and "Adekastub AO-80" were used, and evaluation was carried out in the same manner as in Example 1.

[Comparative Example 2]

An adhesive was prepared in the same manner as in Example 1 except that the acrylic resin obtained in Synthesis Example 8 was used, and "Adekastub AO-80" was not used, and it was evaluated in the same manner as in Example 1.

[Comparative Example 3]

An adhesive was prepared in the same manner as in Example 1 except that the acrylic resin obtained in Synthesis Example 9 was used, lithium perchlorate was used in an amount of 5 g, and "Adekastub AO-80" was not used. The evaluation was carried out in the same manner as in Example 1.

[Comparative Example 5]

An adhesive was prepared in the same manner as in Example 1 except that the acrylic resin obtained in Synthesis Example 2 was used, lithium perchlorate was used in an amount of 5 g, and a curing agent was not used. The evaluation was carried out in the same manner as in Example 1.

[Comparative Example 6]

The acrylic resin solution obtained in Synthesis Example 10 was desolvated, dissolved in acetonitrile, and 3% by weight of lithium perchlorate was added to the solid portion of the acrylic resin to dissolve it. The homogeneous viscous liquid was cast on an aluminum foil, and dried at 80 ° C for about 2 days to completely evaporate the acetone. The obtained resin sheet was laminated to a polyethylene terephthalate film (thickness: 38 μm) and evaluated in the same manner as in Example 1.

[Comparative Example 7]

The same procedure as in Example 1 was carried out except that the acrylic resin obtained in Synthesis Example 7 was used, and Adekastub AO-80 was used, and 1 g of lithium perchlorate was used, and the test adhesive tape was obtained at room temperature for 7 days. The adhesive was evaluated in the same manner as in Example 1.

[Comparative Example 8]

The evaluation was carried out in the same manner as in Example 1 except that the acrylic resin obtained in Synthesis Example 7 was used, and Adekastub AO-80 was used, and 1 g of lithium perchlorate was used, and the test adhesive tape was obtained at 50 ° C for 30 days.

As described above, it is understood that the antistatic adhesive of the present invention is excellent in storage stability, surface resistance (electrical conductivity), transparency, and removability of the main agent.

On the other hand, since the adhesive agent of the comparative example 1 does not contain an alkylene oxide chain and an ionic compound, it is not electrically conductive at all. Since the adhesive shown in Comparative Example 2 does not have an alkylene oxide chain, the ionic compound cannot be dissolved and aggregates, and the transparency and surface resistance are not good. Since the adhesive shown in Comparative Example 3 does not contain a monomer having a hydroxyl group, the crosslinking effect by the curing agent cannot be obtained, and the removability is not good. Further, since the antioxidant is not contained, the main component is stored. Poor stability. Since the adhesive shown in Comparative Example 4 does not contain an ionic compound, it has poor conductivity, and since it does not contain an antioxidant, the storage stability of the main agent is not good. In the adhesive shown in Comparative Example 5, since the hardener was not used at all, the cohesive force was insufficient and the removability was poor.

In Comparative Example 6, the acrylic copolymer (A) was prepared in advance as in the present invention, and the acrylic copolymer (A) was not further hardened between the release paper and the polyethylene terephthalate film. The agent was crosslinked to form an adhesive layer, and only the acrylic resin was laminated on the polyethylene terephthalate film. Since the curing agent was not used, the cohesive force as an adhesive was insufficient, and the removability was poor.

Further, since the adhesives shown in Comparative Examples 7 and 8 did not contain an antioxidant, the storage stability of the main agent was not good. In the case where the antioxidant is not contained, since the surface resistance value of the adhesive layer after the reaction between the main agent and the hardener also becomes larger as time passes, the stability of the antistatic property is not good.

(industrial availability)

The antistatic adhesive of the present invention has good storage stability, has a moderate surface resistance value, and is excellent in transparency and re-peelability, and is therefore suitable for use as a mechanical and electrical property for a specified period on the surface of an adherend. The protective surface protective film can be suitably used for the formation of an adhesive film for surface protection of an optical component such as a liquid crystal panel, a plasma display, a polarizing plate, or a CRT (Brown Tube).

The invention is described above in terms of specific aspects, and variations or modifications which are readily conceivable by those skilled in the art are included in the scope of the invention.

1. . . Plastic film substrate

2. . . Antistatic acrylic adhesive layer

3. . . Polarizer

4. . . Antistatic coating layer

1 is a view showing an antistatic adhesive film of the present invention comprising a PET film substrate and an antistatic acrylic adhesive layer supported on one surface thereof, which is attached to a polarizing plate by an antistatic acrylic adhesive layer. A schematic cross-sectional view of the state.

2 is a schematic cross-sectional view showing an antistatic adhesive film of the present invention in which an antistatic acrylic adhesive layer is provided on both surfaces of a PET film substrate, and an antistatic acrylic adhesive layer is attached to the polarizing plate. Figure.

3 is an antistatic adhesive film of the present invention in which an antistatic coating agent layer is provided on one surface of a PET film substrate and an antistatic acrylic adhesive layer is further carried thereon, and the antistatic coating is used. A schematic cross-sectional view of a state in which the acrylic pressure-sensitive adhesive layer is attached to the polarizing plate 3.

4 is an antistatic adhesive film of the present invention in which an antistatic acrylic adhesive layer is provided on one surface of a PET film substrate and an antistatic coating agent layer is provided on the reverse side surface thereof, and the antistatic adhesive film is used. A schematic cross-sectional view of a state in which the electrostatic acrylic adhesive layer is attached to the polarizing plate 3.

1. . . Plastic film substrate

2. . . Antistatic acrylic adhesive layer

3. . . Polarizer

Claims (14)

An antistatic acrylic adhesive comprising: an acrylic copolymer (A) having a hydroxyl group and an alkylene oxide chain in a side chain, an ionic compound (B), a hardener (C), and an antioxidant (D). The antioxidant (D) is at least one selected from the group consisting of a phenolic antioxidant, a phosphorous acid antioxidant, and a thioether antioxidant. An antistatic acrylic adhesive according to the first aspect of the invention, wherein the alkylene oxide chain has an addition molar number of 4 to 16. An antistatic acrylic adhesive according to claim 1, wherein the alkylene oxide chain is an ethylene oxide chain. The antistatic acrylic adhesive according to the first aspect of the invention, wherein the acrylic copolymer (A) has a weight average molecular weight of 50,000 to 1,000,000. An antistatic acrylic adhesive according to the first aspect of the invention, wherein the ionic compound (B) is liquid or solid at normal temperature. The antistatic acrylic adhesive according to claim 1, wherein the ionic compound (B) is an inorganic salt of an alkali metal or an organic salt of an alkali metal. An antistatic acrylic pressure-sensitive adhesive according to claim 1, which further comprises an acrylic copolymer (E) having no alkylene oxide chain. An antistatic acrylic adhesive according to claim 7, wherein the low molecular weight acrylic copolymer (A1) having a weight average molecular weight of 50,000 to 200,000 in a side chain having a hydroxyl group and an alkylene oxide chain is not The high molecular weight acrylic copolymer (E1) having an average weight molecular weight of the alkylene oxide chain of 200,000 to 1,000,000. The antistatic acrylic pressure-sensitive adhesive according to the first aspect of the invention, wherein the ionic compound (B) is contained in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the acrylic copolymer (A). The antistatic acrylic pressure-sensitive adhesive of the seventh aspect of the invention, wherein the ionic compound (B) is contained in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the total of the acrylic copolymers (A) and (E). The antistatic acrylic pressure-sensitive adhesive according to the first aspect of the invention, wherein the acrylic copolymer (A) is obtained by copolymerizing a monomer having an alkylene oxide chain, and constituting the acrylic copolymer ( In the case where all of the monomers of A) are 100% by weight, the monomer having an alkylene oxide chain is 1 to 60% by weight. The antistatic acrylic pressure-sensitive adhesive of the seventh aspect of the invention, wherein the acrylic copolymer (A) is obtained by copolymerizing a monomer having an alkylene oxide chain, and constituting the acrylic copolymer ( When all of the monomers A) and (E) are 100% by weight, the monomer having an alkylene oxide chain is 1 to 60% by weight. The antistatic acrylic adhesive according to claim 1, wherein the curing agent (C) is a trifunctional isocyanate compound and/or a polyfunctional epoxy compound. A protective film for an optical member, characterized in that an adhesive layer formed of an antistatic acrylic adhesive of the first application of the patent application is laminated on at least one side of a plastic film substrate.