JP2008045057A - Method for producing acrylic adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method by which a solvent-type antistatic adhesive suitable as the adhesive for a surface-protecting adhesive film of various kinds of optical members such as a polarizing plate, having excellent transparency, hardly having color, having excellent removability, and hardly causing electrification by peeling at the peeling can be produced safely. <P>SOLUTION: The method for producing the solvent-type antistatic acrylic adhesive includes mixing a solution of an acrylic copolymer (A) having a hydroxy group and an alkylene oxide chain on the side chain, an aqueous solution of an ion compound (B) and a curing agent (C). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a method for producing a solvent-type acrylic pressure-sensitive adhesive. In detail, this invention relates to the manufacturing method of the adhesive suitable for the surface protection film for protecting the to-be-adhered body surface mechanically and electrically for a predetermined period.
The pressure-sensitive adhesive obtained by the production method of the present invention is suitably used for forming a surface-protective pressure-sensitive adhesive film for optical components such as liquid crystal panels, plasma displays, polarizing plates, and CRTs (CRTs).

  Conventionally, the surface of various displays such as word processors, computers, mobile phones, televisions, or optical components such as polarizing plates and laminates equivalent thereto, electronic substrates, and the like are usually polyethylene for the purpose of surface protection and functionality. A transparent surface protective film (base film) such as polyester or polypropylene is laminated via an adhesive.

  In many cases, these surface protective pressure-sensitive adhesive films are peeled and removed after finishing the role of surface protection, for example, after the incorporation of a liquid crystal display or the like is completed. However, there is a problem that static electricity is generated when the surface protective adhesive film is peeled off and entraps surrounding dust. Furthermore, there may be a problem that the liquid crystal and the electronic circuit are destroyed due to peeling electrification generated when the surface protective adhesive film is peeled off.

Therefore, various measures have been proposed as means for imparting antistatic properties to the surface protective adhesive film.
As typical methods, for example, the following three methods can be mentioned.
For example,
(1) A method of imparting antistatic properties to the base film itself constituting the surface protective adhesive film,
(2) Between the base film and the pressure-sensitive adhesive layer constituting the surface protective pressure-sensitive adhesive film, on the side where the pressure-sensitive adhesive layer of the base film is not laminated, or between the base film and the pressure-sensitive adhesive layer A method of providing a layer having antistatic performance in between,
(3) A method of imparting antistatic properties to the pressure-sensitive adhesive layer constituting the surface protective pressure-sensitive adhesive film, etc.

The method (1) is a method in which a conductive base material is prepared by kneading an anionic compound such as an organic sulfonate group, a metal powder, or a conductive filler such as carbon black with a thermoplastic resin such as polyester or polyethylene as a raw material for the base film. In this case, the transparency of the base film is lowered or the film is colored.
By the way, even while the surface protective adhesive film is adhered to the adherend, the surface protective appearance of the adherend needs to be constantly inspected through the adhesive film. Therefore, the surface protective adhesive film pressure-sensitive adhesive sheet itself is required to be excellent in transparency and optically free from defects.
Therefore, when the surface protection adhesive film using an antistatic agent containing base film is stuck to a to-be-adhered body, there exists a problem that a to-be-adhered surface becomes difficult to see. There is also a problem that the base film becomes expensive.

The method (2) has various variations as shown below (for example, Patent Documents 1 to 5).
(2-1) A method of depositing a metal compound on at least one surface of a base film,
(2-2) An anionic surfactant such as a quaternary ammonium salt, a long-chain alkyl compound having a sulfonate group, a thiophene derivative, or a nitrogen element ionized in the main chain on at least one surface of the base film And a method of providing a layer containing various antistatic agents such as sulfonate group-modified polystyrene.
However, since an anionic surfactant such as a long-chain alkyl compound having a sulfonate group has a relatively low molecular weight, a part of the antistatic agent moves through the antistatic coating film to form a base film. There is a problem of accumulating at the interface and transferring to the opposite surface of the base film, and a problem that the antistatic property decreases with time.
In addition, since the polymer having nitrogen element ionized in the main chain, sulfonate group-modified polystyrene, and the like have a relatively high molecular weight, the above-described problems do not occur. However, in order to obtain good antistatic performance, it is necessary to add a large amount of antistatic agent, and it is not economical because it is necessary to increase the thickness of the antistatic layer. Furthermore, when scrap film that has not been turned into a product (for example, film edges cut and removed in the manufacturing process) is collected and used as a recycled material for film production, it is included in the recycled material during melt film formation. There arises a problem that the antistatic agent component is thermally deteriorated, and the film to be regenerated is extremely colored and lacks practicality (recoverability is poor). In addition, there are disadvantages that the films are difficult to peel (block) and the coating film is easily scraped, and the solution is desired.

The method (3) is a method of imparting antistatic performance to the peeling interface where static electricity is generated, and a method of forming a pressure sensitive adhesive using a resin having antistatic performance, and a pressure sensitive adhesive containing an antistatic agent-containing pressure sensitive adhesive. There is a method of forming a layer (Patent Document 6).
In the former case, the antistatic performance of the resin itself, which can be paraphrased as electrical conductivity, is insufficient.
In the latter case, examples of the antistatic agent used include various surfactants and conductive powders such as carbon black. However, when a surfactant-containing pressure-sensitive adhesive is used, the surfactant generally tends to be concentrated on the surface of the pressure-sensitive adhesive layer, i.e., the bonding interface with the adherend, and the pressure-sensitive adhesive performance is low due to the surfactant. Very sensitive. That is, when moisture reduces the cohesive force of the pressure-sensitive adhesive layer and peels off the surface protective pressure-sensitive adhesive film, a part of the pressure-sensitive adhesive layer tends to remain on the adherend (so-called “glue residue”). On the other hand, when a conductive pressure-sensitive adhesive containing conductive powder such as carbon black is used, there arises a problem that transparency of the pressure-sensitive adhesive layer and the surface protective pressure-sensitive adhesive film is lowered or the film is colored.

The use of an antistatic agent that 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 is for an electrode pad that is used by being attached to a living body, although it relates to a conductive adhesive, and the conductive adhesive described in Patent Document 7 is a surface protective adhesive film. It could not be used at all.

Patent Document 8 discloses an antistatic pressure-sensitive adhesive containing an ionic compound.
This pressure-sensitive adhesive has excellent performance as an antistatic pressure-sensitive adhesive, but it is difficult to handle ionic compounds (such as lithium perchlorate) in the manufacturing process, and is particularly dangerous when mixed with an organic solvent. It was seen.
Japanese Patent Laid-Open No. 7-26223 JP 11-256116 A JP 2001-219520 A JP 2002-060707 A JP 2002-275296 A JP-A-1-253482 Japanese Patent No. 2718519 Japanese Patent Application Laid-Open No. 2005-206776

  The object of the present invention is suitable as a pressure-sensitive adhesive for surface protective adhesive films of optical members such as various displays and polarizing plates, has excellent transparency and little coloration, has excellent removability, and has little peeling charge upon peeling. It aims at providing the manufacturing method which can manufacture an antistatic adhesive safely.

  As a result of intensive studies, the present inventor has found that an antistatic pressure-sensitive adhesive having appropriate conductivity can be safely produced by blending an ionic compound as an aqueous solution, and has completed the present invention. .

  That is, the present invention is a solvent characterized by mixing a solution of an acrylic copolymer (A) having a hydroxyl group and an alkylene oxide chain in the side chain, an aqueous solution of an ionic compound (B), and a curing agent (C). The present invention relates to a method for producing a type antistatic acrylic adhesive.

  The present invention also relates to a process for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to the invention, wherein the alkylene oxide chain is an ethylene oxide chain.

  The present invention also relates to the method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to any one of the above inventions, wherein the acrylic copolymer (A) has a weight average molecular weight of 50,000 to 1,000,000.

  Further, the present invention provides the solvent-type charging according to any one of the above inventions, wherein the ionic compound (B) is 0.01 to 30 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). The present invention relates to a method for producing a prevention acrylic adhesive.

  The present invention also relates to a method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to any one of the above inventions, wherein the ionic compound (B) is an inorganic salt.

  In the present invention, the acrylic copolymer (A) is obtained by subjecting a monomer having an alkylene oxide chain to copolymerization, and the total amount of monomers constituting the acrylic copolymer (A) is 100% by weight. Further, the present invention relates to a method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to any one of the above inventions, wherein the monomer having an alkylene oxide chain is 1 to 60 wt%.

  The present invention also relates to a method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to any one of the above inventions, wherein the curing agent (C) is a trifunctional isocyanate compound and / or a polyfunctional epoxy compound.

  Furthermore, the present invention relates to a solvent-type antistatic acrylic pressure-sensitive adhesive obtained by any one of the above-described production methods.

  Furthermore, the present invention relates to a protective film for an optical member, characterized in that an adhesive layer formed from the solvent-type antistatic acrylic adhesive of the present invention is laminated on at least one surface of a plastic film substrate.

  According to the present invention, it is possible to safely produce an antistatic pressure-sensitive adhesive having an appropriate surface resistance value and excellent in transparency and removability.

  The acrylic copolymer (A) used in the present invention has a hydroxyl group and an alkylene oxide chain, an acrylic monomer (a1) having a hydroxyl group, an acrylic monomer (a2) having an alkylene oxide chain, As needed, it can synthesize | combine from the other acrylic monomer (a3) copolymerizable with these (namely, acrylic monomer (a3) which has neither a hydroxyl group nor an alkylene oxide chain).

  Examples of the acrylic monomer (a1) having a hydroxyl group used in the present invention include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and glycerol mono (meth). An acrylate etc. are mentioned. In the present invention, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable.

  In the present invention, the purpose of using the acrylic monomer (a1) having a hydroxyl group is to ensure the removability while ensuring the adhesive force to the adherend. More specifically, a cross-linked structure is formed by utilizing the reaction between a curing agent (C) such as an isocyanate curing agent described later used in forming the pressure-sensitive adhesive layer and these hydroxyl groups, and as described later. By controlling the molecular weight of the acrylic copolymer (A), it is possible to balance the adhesive strength and the removability.

  Therefore, when the sum total of the monomer which comprises an acryl-type copolymer (A) is 100 weight%, it is preferable that the acryl-type monomer (a1) which has a hydroxyl group is 1-30 weight%. More preferably, it is 3 to 10% by weight. If the acrylic monomer (a1) having a hydroxyl group is less than 1% by weight, the degree of crosslinking and cohesion as the pressure-sensitive adhesive layer are insufficient, and the pressure-sensitive adhesive force becomes excessively large or adhesive residue tends to occur. If it exceeds 30% by weight, the degree of crosslinking becomes too high and the tackiness becomes poor.

  Examples of the acrylic monomer (a2) having an alkylene oxide chain used in the present invention include a monomer having an ethylene oxide chain, a monomer having a propylene oxide chain, and a monomer having both.

Examples of the monomer having an ethylene oxide chain include methoxypolyethylene glycol (meth) acrylate and polyethylene glycol (meth) acrylate.
Examples of the monomer having a propylene oxide chain include methoxypolypropylene glycol (meth) acrylate and polypropylene glycol (meth) acrylate.
In the present invention, in view of compatibility with an aqueous solution of an ionic compound (B) described later, a monomer having an ethylene oxide chain is preferable, and methoxypolyethylene glycol (meth) acrylate is particularly preferable.

There are two purposes for using the acrylic monomer (a2) having an alkylene oxide chain in the present invention.
The first is to adsorb water contained in the aqueous solution of the ionic compound (B) to the alkylene oxide chain and suppress the reaction between the isocyanate curing agent described later and water. In addition, the hydrophilic action of the monomer having an alkylene oxide chain makes it possible to stably take in water, and it is stable without containing aggregates or separating the solution while containing water. This is because an excellent pressure-sensitive adhesive solution can be obtained.
The second is to form a complex between the ionic compound (B) and the alkylene oxide to develop conductivity. Therefore, the role of the alkylene oxide chain is very large and not only provides a field for complex formation, but also serves as a transfer medium for the ionic compound (B). In other words, the conductivity in the present invention varies greatly depending on the amount of the ionic compound (B) and the content of the monomer (a2) having an alkylene oxide chain.

  Therefore, when the total amount of the monomers constituting the acrylic copolymer (A) is 100% by weight, the acrylic monomer (a2) having an alkylene oxide chain is preferably 1 to 60% by weight. More preferably, it is 5 to 50% by weight.

As the monomer (a3) copolymerizable with the above acrylic monomer used in the present invention, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) Acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) Acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate Rate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, heneicosyl (meth) acrylate, docosyl (meth) acrylate and (meth) acrylic acid. In the present invention, it is preferable to subject the acrylic monomer (a3) having 4 to 12 carbon atoms to copolymerization in terms of securing the adhesive physical properties. More preferred are butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate.
These can be appropriately selected and used alone or in combination of two or more for the purpose of obtaining desirable physical properties as an adhesive.

Weight average molecular weight of the acrylic copolymer (A) obtained by copolymerizing the acrylic monomer (a1) having a hydroxyl group, the acrylic monomer (a2) having an alkylene oxide chain, and other monomers (a3). (Mw) is preferably 50,000 to 1,000,000.
When the weight average molecular weight is less than 50,000, the cohesive force of the pressure-sensitive adhesive layer to be formed tends to be reduced, and adhesive residue tends to be generated when peeling from the adherend.
On the other hand, when the weight average molecular weight exceeds 1,000,000, handling becomes difficult, and further, the cohesive force becomes excessively high and the inconvenience that the adhesive force to the optical member becomes large is likely to occur.

The acrylic copolymer (A) can be obtained by radical polymerization of the monomers (a1) to (a2) or the monomers (a1) to (a3) in an organic solvent in the presence of a polymerization initiator.
As the polymerization initiator, conventionally known initiators such as peroxide polymerization initiators such as benzoyl peroxide and azo compound polymerization initiators such as azobisisobutyronitrile can be used.
Examples of the organic solvent used as the reaction solvent include ethyl acetate, toluene, MEK (methyl ethyl ketone), IPA (isopropyl alcohol), acetone, and methyl acetate. In the present invention, considering the solubility of the acrylic resin, ethyl acetate and toluene are preferable.
The reaction temperature is usually about 50 to 100 ° C., and the polymerization reaction is carried out for 3 to 10 hours.

The pressure-sensitive adhesive for the protective film for optical members is required to have an antistatic function, removability and transparency. Therefore, from the viewpoint of the antistatic function, it is preferable that the acrylic copolymer (A) contains more alkylene oxide chains.
By the way, some optical members are very thin and fragile, while others are relatively strong. Depending on the type of adherend to which the protective film is attached, the protective film and adhesive are required. The magnitude of the peel force applied is different.
That is, when the fragile optical member is used as an adherend, the peeling force is preferably 200 g / 25 mm or less so as not to damage the adherend when the protective film is peeled off after sticking. More preferably, it is 100 g / 25 mm or less.
On the other hand, when a relatively strong optical member is used as the adherend, the peeling force can be allowed to be about 1000 g / 25 mm.
It should be noted that it is always required that the pressure-sensitive adhesive does not remain on the adherend when it is peeled regardless of the adherend.

  The peel strength of the pressure-sensitive adhesive is greatly affected by the cohesive strength of the acrylic copolymer (A) itself, which is the main component constituting the pressure-sensitive adhesive, and the state of crosslinking between the main component and the curing agent (C) described later. Receive. In general, the peeling force can be reduced by using a large amount of the curing agent (C) with respect to the main component. In general, the cohesive force of the main component itself can be increased by increasing the molecular weight of the main component.

Next, an aqueous solution of the ionic compound (B) used in the present invention will be described.
The aqueous solution of the ionic compound (B) in the present invention is a solution obtained by dissolving the ionic compound (B) described later in water, and it may be dissolved at room temperature. Can be dissolved.
Many of the ionic compounds are water-soluble, and can form a complex with the alkylene oxide chain in the acrylic copolymer (A) having an alkylene oxide chain used in the present invention to exhibit conductivity. However, some ionic compounds have poor compatibility with the alkylene oxide chain. When such compounds are used, they are difficult to dissolve during the production of the pressure-sensitive adhesive and exhibit sufficient conductivity. It may not be possible. The ionic compound is not added as it is as in the present invention, but can be added in a stable state by adding it as an aqueous solution.
In addition, among ionic compounds, there are hazardous permeates such as lithium perchlorate and potassium chlorate, and it is very dangerous to directly mix them with an organic solvent. In that case, by adding it as an aqueous solution as in the present invention, safety is ensured and it can be used without any problem.

Next, the relationship between the acrylic copolymer (A) having an alkylene oxide chain and the aqueous solution of the ionic compound (B) will be described.
In general, an aqueous solution, that is, a composition containing water is rarely added to the solvent-type pressure-sensitive adhesive solution. The reason for this is not only that the solution is whitened or separated due to the presence of water, but when an isocyanate curing agent is used as the curing agent, the water and isocyanate in the solution react first, causing poor curing. This is because the coating film is whitened.

In the present invention, an isocyanate curing agent is preferably used, but the above-described problems are unlikely to occur. The reason is that many alkylene oxide chains contained in the acrylic copolymer (A) of the present invention capture water in the aqueous solution and suppress the reaction between water and the curing agent. Therefore, as described above, when the total amount of monomers constituting the acrylic copolymer (A) is 100% by weight, the monomer having an alkylene oxide chain is preferably 1 to 60% by weight, more preferably 5 to 5%. 50% by weight. If it is less than 1%, moisture cannot be sufficiently captured, so that curing failure is liable to occur, and if it exceeds 60% by weight, good adhesive performance is difficult to obtain.
In the solvent-type pressure-sensitive adhesive obtained by the production method of the present invention, the solvent is removed by drying in an oven or the like when forming the pressure-sensitive adhesive layer. At that time, the water trapped in the alkylene oxide chain quickly evaporates together with the organic solvent, and no water remains in the pressure-sensitive adhesive coating film.

  The concentration of the aqueous solution of the ionic compound (B) is preferably 1% by weight to 60% by weight, and more preferably 5% by weight to 50% by weight. If the amount is less than 1% by weight, the amount of water added to the resin solution becomes too large, so that the compatibility tends to be poor or poor curing occurs. The solubility of B) tends to be poor.

Examples of the ionic compound (B) used in the present invention include sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, ammonium chloride, potassium chlorate, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate. , Inorganic salts such as potassium nitrate, sodium nitrate, sodium carbonate, sodium thiocyanate,
Organic salts such as sodium acetate, sodium alginate, sodium lignin sulfonate, and sodium toluene sulfonate are listed.
These can be used alone or in combination. In view of conductivity and safety, inorganic salts are preferable, and among them, sodium chloride, potassium chloride, lithium perchlorate and the like are particularly preferable.

  Moreover, it is preferable that the usage-amount of an ionic compound (B) is 0.01-30 weight part with respect to 100 weight part of acrylic copolymers (A). More preferably, it is 0.1-10 weight part. If it is less than 0.01 part by weight, sufficient ionic conductivity cannot be obtained, and even if it contains more than 30 parts by weight of an ionic compound, the effect of improving conductivity can hardly be expected. This is not preferable because the coating film is likely to be whitened due to a decrease in compatibility.

The stability over time of the pressure-sensitive adhesive film using the solvent-type antistatic acrylic pressure-sensitive adhesive obtained by the present invention, that is, the protective film for optical members, includes the amount of the ionic compound (B) contained and the acrylic copolymer (A ) Greatly affects the amount of alkylene oxide chain contained.
When the amount of the alkylene oxide chain is large, a complex can be formed efficiently with the ionic compound (B), but when the amount of the alkylene oxide chain is small and the amount of the ionic compound is large, an excess that cannot form a complex is formed. The ionic compound moves to the surface of the pressure-sensitive adhesive layer, and the whitening phenomenon as described above tends to occur. In addition, the surface resistance value with time tends to increase.
From these viewpoints, it is preferable to increase the amount of alkylene oxide chains contained in the pressure-sensitive adhesive layer as much as possible and to add the minimum ionic compound (B) capable of expressing the required conductivity.

In the present invention, it is important to use the curing agent (C) in order to increase the cohesive strength and the degree of crosslinking.
The curing agent (C) of the present invention preferably has two or more functional groups that can react with a functional group such as a hydroxyl group contained in the acrylic copolymer (A) 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.

  The known trifunctional isocyanate compound includes a so-called adduct obtained by modifying a known diisocyanate compound with a trifunctional polyol component, a burette obtained by reacting the diisocyanate compound with water, and a 3 amount having an isocyanurate ring formed from three molecules of the diisocyanate compound. The body (isocyanurate body) can be used.

  Known diisocyanate compounds include aromatic diisocyanates, aliphatic diisocyanates, araliphatic diisocyanates, alicyclic diisocyanates, and the like.

  As aromatic diisocyanates, 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate Examples thereof include isocyanate, 4,4′-toluidine diisocyanate, dianisidine diisocyanate, and 4,4′-diphenyl ether diisocyanate.

  Aliphatic diisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4 , 4-trimethylhexamethylene diisocyanate and the like.

  Examples of the araliphatic diisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene, 1, Examples include 4-tetramethylxylylene diisocyanate and 1,3-tetramethylxylylene diisocyanate.

  Examples of alicyclic diisocyanates include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4- Examples include cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanatomethyl) cyclohexane and the like.

  As the diisocyanate compound used in the present invention, it is preferable to use 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (also known as isophorone diisocyanate).

  The 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 diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A / epichlorohydrin type epoxy resin, N, N, N′N′-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N-diglycidylaniline, N, N-diglycidyltoluidine, etc. It is done.

About the above-mentioned hardening | curing agent (C), a trifunctional isocyanate compound and a polyfunctional epoxy compound can be used individually and in combination, respectively. When used in applications that place importance on flexibility, it is preferable to use a trifunctional isocyanate compound. When heat resistance is required, it is preferable to use a polyfunctional epoxy compound.
As described above, when a low peeling force of 200 g / 25 mm or less, preferably 100 g / 25 mm or less is required, when using a trifunctional isocyanate compound, the acrylic copolymer (A) is used in 100 parts by weight. It is preferable to use 1 to 30 parts by weight of the curing agent (C), more preferably 2 to 20 parts by weight, and further preferably 3 to 15 parts by weight.
Moreover, when using a polyfunctional epoxy compound, in order to act as a crosslinking agent more effectively, it is preferable that acrylic acid or methacrylic acid is contained in the acrylic copolymer (A). About the content, it is preferable that it is 0.5 to 5% by weight ratio in all the acrylic monomers. If it is less than 0.5%, it does not sufficiently act as a crosslinking agent, and if it exceeds 5%, the pot life after the addition of the curing agent (C) tends to be short, such being undesirable. The amount of the curing agent (C) is preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A).

A solvent-type antistatic acrylic pressure-sensitive adhesive can be obtained by mixing a solution of the acrylic copolymer (A), an aqueous solution of the ionic compound (B), and a curing agent (C).
As a solution of the acrylic copolymer (A), a polymer solution obtained by radical polymerization of the monomers (a1) to (a2) or the monomers (a1) to (a3) in an organic solvent can be used as it is. However, if necessary, a solvent may be further added for dilution, and then mixed with other components.
In mixing, a conventionally known stirrer such as a disper can be used, but since an organic solvent is contained, it is preferable to mix in a closed system from the viewpoint of safety and environmental sanitation. If necessary, the inside of the system may be an inert gas atmosphere such as nitrogen gas.

The solvent-type antistatic acrylic adhesive obtained in the present invention has an acrylic copolymer other than the acrylic copolymer (A), for example, a hydroxyl group, and an alkylene oxide chain in order to control the adhesive physical properties of the adhesive. You may contain the acrylic copolymer which does not have.
Such an acrylic copolymer can be obtained by a method similar to that for the acrylic copolymer (A) by appropriately selecting a monomer.

If necessary, an aqueous solution of a water-soluble compound can be added to the solvent-type antistatic adhesive obtained in the present invention. As an addition method, first, an aqueous solution is prepared by dissolving a water-soluble compound in water, and then a solution of an acrylic copolymer (A), an aqueous solution of an ionic compound (B), a curing agent (C), and as necessary. What is necessary is just to mix with the other component used according to it.
Specific examples of water-soluble compounds include surfactants and conductive polymers.

  The solvent-type antistatic pressure-sensitive adhesive obtained in the present invention can be used in combination with other resins such as acrylic resin, polyester resin, amino resin, epoxy resin, and polyurethane resin as necessary. Depending on the application, tackifiers, talc, calcium carbonate, titanium oxide and other fillers, colorants, ultraviolet absorbers, antioxidants, antifoaming agents, light stabilizers, curing accelerators, curing retarders, You may mix | blend additives, such as phosphate ester.

Using the solvent-type antistatic pressure-sensitive adhesive obtained in the present invention, a pressure-sensitive adhesive sheet obtained by laminating a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive and a substrate such as a plastic film, paper, cloth, or foam is obtained. The surface of the pressure-sensitive adhesive layer can be covered with a release sheet.
The pressure-sensitive adhesive sheet can be obtained by applying or impregnating a pressure-sensitive adhesive to various substrates, and drying and curing it. Alternatively, a pressure-sensitive adhesive is applied on the release sheet, dried, and various substrates are laminated on the surface of the pressure-sensitive adhesive layer that is being formed, and a hydroxyl group in the pressure-sensitive adhesive and an isocyanate group in the curing agent (C), or It can also be obtained by advancing the reaction between the carboxyl group in the pressure-sensitive adhesive and the epoxy group in the curing agent (C).

  By applying the solvent-type pressure-sensitive adhesive obtained in the present invention to a transparent plastic film among the base materials, a surface protective pressure-sensitive adhesive film for an optical member can be suitably obtained.

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

The solvent-type antistatic pressure-sensitive adhesive obtained in the present invention is preferably applied to a substrate or the like so as to have a thickness of about 2 to 200 μm when dried and cured. If it is less than 2 μm, the ionic conductivity becomes poor, and if it exceeds 200 μm, the production and handling of the pressure-sensitive adhesive sheet becomes difficult.
In this way, an antistatic pressure-sensitive adhesive film having a surface resistance value of the pressure-sensitive adhesive layer of 10 ¹² Ω / □ or less can be obtained.

The solvent-type antistatic pressure-sensitive adhesive obtained in the present invention is used, and the antistatic pressure-sensitive adhesive film of various aspects can be obtained in consideration of its use and required performance.
For example, an antistatic pressure-sensitive adhesive film for a protective film for a polarizing plate will be described with reference to the drawings.
FIG. 1 shows an antistatic pressure-sensitive adhesive film according to the present invention comprising a PET (polyethylene terephthalate) film substrate 1 and an antistatic acrylic pressure-sensitive adhesive layer 2 carried on one surface thereof. FIG. 4 is a schematic cross-sectional view showing a state of being attached to a polarizing plate 3.

  FIG. 2 shows a state in which an antistatic pressure-sensitive adhesive film according to the present invention in which an antistatic acrylic pressure-sensitive adhesive layer 2 is provided on both surfaces of a PET film substrate 1 is attached to a polarizing plate 3 with one antistatic acrylic pressure-sensitive adhesive layer 2. It is a typical sectional view shown.

  FIG. 3 shows an antistatic adhesive film according to 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 supported thereon. FIG. 3 is a schematic cross-sectional view showing a state where the protective acrylic pressure-sensitive adhesive layer 2 is attached to the polarizing plate 3.

  FIG. 4 shows an antistatic adhesive film according to 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 opposite surface. FIG. 3 is a schematic cross-sectional view showing a state where the protective acrylic pressure-sensitive adhesive layer 2 is attached to the polarizing plate 3.

When the adhesive of the present invention is used for a film for protecting the surface 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 peel charge amount. Is possible.
In applications where the plastic film has functionality, as shown in FIG. 2, an antistatic acrylic pressure-sensitive adhesive layer is provided on both sides of the base film, and the functional film is provided on one antistatic acrylic pressure-sensitive adhesive layer. (For example, a retardation film, an optical compensation film, a light diffusion film, an electromagnetic wave shielding film, etc.) can be further bonded.
In consideration of workability and production cost, the embodiment of FIG. 1 is most preferable.

  As shown in FIG. 3 and FIG. 4, an antistatic coating layer having no adhesiveness is provided between the adhesive layer and the plastic film substrate, or on the opposite side (top coat) of the plastic film substrate that is not the adhesive layer side. Examples of the antistatic agent to be used 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 antimony oxide, and metals such as carbon, silver and copper. In consideration of the transparency of the coating film, tin oxide, antimony oxide and the like are preferable.

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

  The antistatic coating agent layer preferably has a thickness of 0.1 μm to 50 μm, more preferably 1 μm to 20 μm, as a coating film. If the thickness is less than 0.1 μm, the antistatic performance cannot be sufficiently exhibited.

(Synthesis Example 1)
An acrylic copolymer (A) composed of monomers having the composition ratio shown in Table 1 was obtained in the following manner.
That is, a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was used, and the reaction kettle was 46% by weight of 2EHA [46 of “68”% by weight described in Table 1] Meaning of% by weight; the same applies hereinafter), 50% by weight of BA, 50% by weight of 2HEA, total amount of AM90G, ethyl acetate as solvent, azobisisobutyronitrile as initiator,
A total amount of the remaining monomers, ethyl acetate, and azobisisobutyronitrile added in appropriate amounts and mixed were added dropwise over about 1 hour and polymerized at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate. This reaction solution had a solid content of 40%, a viscosity of 1300 cps, and Mw (weight average molecular weight) of 310,000.

(Synthesis Example 2)
An acrylic copolymer (A) composed of monomers having the composition ratio shown in Table 1 was obtained in the following manner.
That is, a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was used. The reaction kettle was 44% by weight of 2EHA, 2% by weight of HEA, the total amount of M40G, and ethyl acetate as a solvent. , Charge an appropriate amount of azobisisobutyronitrile as an initiator,
A total amount of the remaining monomers, ethyl acetate, and azobisisobutyronitrile added in appropriate amounts and mixed were added dropwise over about 1 hour and polymerized at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate. This reaction solution had a solid content of 41%, a viscosity of 1200 cps, and a Mw (weight average molecular weight) of 350,000.

(Synthesis Example 3)
An acrylic copolymer (A) composed of monomers having the composition ratio shown in Table 1 was obtained in the following manner.
That is, a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was used. The reaction kettle was 35% by weight of 2EHA, 30% by weight of BA, 30% by weight of 2HEA, A suitable amount of ethyl acetate and azobisisobutyronitrile as an initiator is charged.
Next, 42% by weight of 2EHA, 40% by weight of BA, 40% by weight of 2HEA, 30% by weight of M90G, ethyl acetate and azobisisobutyronitrile were added in an appropriate amount and mixed for about 1 hour. The solution was dropped and polymerized at about 80 ° C. for 1 hour in a nitrogen atmosphere.
Thereafter, a total amount of the remaining monomers, ethyl acetate, and azobisisobutyronitrile were added in appropriate amounts and mixed, and the solution was added dropwise over about 1 hour and polymerized at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate and toluene. This reaction solution had a solid content of 40%, a viscosity of 1500 cps, and Mw (weight average molecular weight) of 330,000.

(Synthesis Example 4)
An acrylic copolymer (A) composed of monomers having the composition ratio shown in Table 1 was obtained in the following manner.
That is, a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was used. The reaction kettle was 40% by weight of 2EHA, 30% by weight of BA, 30% by weight of 2HEA, A suitable amount of ethyl acetate and azobisisobutyronitrile as an initiator is charged.
Next, an appropriate amount of 46% by weight of 2EHA, 40% by weight of BA, 40% by weight of 2HEA, 20% by weight of M90G, ethyl acetate and azobisisobutyronitrile was added and mixed for about 1 hour. The solution was added dropwise and polymerized at about 80 ° C. for 1 hour in a nitrogen atmosphere.
Thereafter, a solution prepared by adding a proper amount of all the remaining monomers, ethyl acetate and azobisisobutyronitrile was added dropwise over about 1 hour, and polymerization was performed at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate and toluene. This reaction solution had a solid content of 40%, a viscosity of 3700 cps, and Mw (weight average molecular weight) of 250,000.

(Synthesis Example 5)
An acrylic copolymer (A) composed of monomers having the composition ratio shown in Table 1 was obtained in the following manner.
That is, a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer and a dropping funnel was used. The reaction kettle was 74% by weight of 2EHA, 50% by weight of 2HEA, ethyl acetate as a solvent, and as an initiator. An appropriate amount of azobisisobutyronitrile is charged,
A total amount of the remaining monomers, ethyl acetate, toluene, and azobisisobutyronitrile added in appropriate amounts and mixed were added dropwise over about 1 hour and polymerized at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with toluene. This reaction solution had a solid content of 41%, a viscosity of 1000 cps, and Mw (weight average molecular weight) of 110,000.

(Synthesis Example 6)
An acrylic copolymer (A) composed of monomers having the composition ratio shown in Table 1 was obtained in the following manner.
That is, a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was used, and the reaction kettle was 44% by weight of 2EHA, 50% by weight of BA, 50% by weight of 2HEA, 50% by weight, total amount of M40G, ethyl acetate as solvent, azobisisobutyronitrile as initiator,
A total amount of the remaining monomers, ethyl acetate, and azobisisobutyronitrile added in appropriate amounts and mixed were added dropwise over about 1 hour and polymerized at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate. This reaction solution had a solid content of 40%, a viscosity of 2000 cps, and Mw (weight average molecular weight) of 320,000.

(Synthesis Example 7)
An acrylic copolymer (A) composed of monomers having the composition ratio shown in Table 1 was obtained in the following manner.
That is, a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was used. The reaction kettle was 100% by weight of 2EHA, 63% by weight of BA, 50% by weight of 2HEA, A suitable amount of ethyl acetate and azobisisobutyronitrile as an initiator is charged.
A total amount of the remaining monomers, ethyl acetate, and azobisisobutyronitrile added in appropriate amounts and mixed were added dropwise over about 1 hour and polymerized at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate. This reaction solution had a solid content of 40%, a viscosity of 400 cps, and a Mw (weight average molecular weight) of 105,000.

(Synthesis Example 8)
The acrylic copolymer which does not contain the alkylene oxide chain | strand comprised from the monomer of the composition ratio shown in Table 1 was obtained in the following ways.
That is, a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was used. The reaction kettle was 50% by weight of 2EHA, 50% by weight of BA, 50% by weight of 2HEA, A suitable amount of ethyl acetate and azobisisobutyronitrile as an initiator is charged.
A total amount of the remaining monomers, ethyl acetate, and azobisisobutyronitrile added in appropriate amounts and mixed were added dropwise over about 1 hour and polymerized at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate. This reaction solution had a solid content of 41%, a viscosity of 1700 cps, and Mw (weight average molecular weight) 400,000.

(Synthesis Example 9)
An acrylic copolymer containing no hydroxyl group and composed of monomers having the composition ratio shown in Table 1 was obtained as follows.
That is, a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was used. The reaction kettle was 35% by weight of 2EHA, 30% by weight of BA, ethyl acetate as a solvent, and as an initiator. An appropriate amount of azobisisobutyronitrile is charged,
Next, a solution prepared by adding appropriate amounts of 42% by weight of 2EHA, 40% by weight of BA, 30% by weight of M90G, ethyl acetate and azobisisobutyronitrile was added dropwise over about 1 hour, Polymerization was carried out at about 80 ° C. for 1 hour.
Thereafter, a solution prepared by adding appropriate amounts of the remaining monomers, ethyl acetate, and azobisisobutyronitrile was added dropwise over about 1 hour and polymerized at about 80 ° C. for 5 hours in a nitrogen atmosphere. After completion of the reaction, the mixture was cooled and diluted with ethyl acetate and toluene. This reaction solution had a solid content of 40%, a viscosity of 1300 cps, and a Mw (weight average molecular weight) of 350,000.

[Example 1]
Compounding 30 g of 30% aqueous solution of lithium perchlorate and 40 g of 37% ethyl acetate solution of tolylene diisocyanate trimethylolpropane adduct as a curing agent for 40 g of the solid content of the acrylic resin solution obtained in Synthesis Example 1. A pressure sensitive adhesive was obtained.
The obtained pressure-sensitive adhesive was coated on a release paper so as to have a dry coating film thickness of 20 μm, dried at 100 ° C. for 2 minutes, and then a polyethylene terephthalate film (thickness 50 μm) was laminated on the pressure-sensitive adhesive layer being formed. The adhesive tape for a test was obtained by making it pass at room temperature for 7 days in the state.
Using the pressure-sensitive adhesive tape, the adhesive strength, surface resistance value, removability, and transparency were evaluated according to the following methods.

<Adhesive strength>
The release paper of the test pressure-sensitive adhesive tape was peeled off, and the exposed pressure-sensitive adhesive layer was attached to a glass plate having a thickness of 0.4 mm at 23 ° C.-65% RH, and roll-bonded according to JIS Z-0237. Peel strength (180 degree peel, pulling speed 300 mm / min; unit g / 25 mm width) was measured with a shopper type peel tester after 24 hours from the press bonding.

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

<Removability>
After peeling the release paper of the test adhesive tape and sticking the exposed adhesive layer to a glass plate, it was left to stand for 24 hours under conditions of 60 ° C.-95% RH and cooled to 23 ° C.-65% RH. After peeling off from the glass plate, the adhesive residue on the glass plate was visually evaluated. Specifically, the state after peeling was evaluated in the following four stages.
No adhesive transfer to the adherend ◎
Very few ○
Partially △
Fully migrated ×

<Transparency>
After peeling the release paper of the test adhesive tape and sticking the exposed adhesive layer to a glass plate, it was left to stand for 24 hours under conditions of 60 ° C.-95% RH and cooled to 23 ° C.-65% RH. And then visually evaluated.
Colorless and transparent ◎
Very slightly cloudy ○
Those that are cloudy or aggregated △
Not transparent ×

[Examples 2, 3, and 5] [Comparative Example 3]
A pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that each acrylic resin solution obtained in Synthesis Examples 2, 3, 5, and 9 was used, and evaluated in the same manner as in Example 1.

[Example 4]
A pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that the acrylic resin solution obtained in Synthesis Example 4 was used and 3.33 g of a 30% aqueous solution of lithium chloride was used instead of lithium perchlorate. And evaluated in the same manner.

[Example 6]
The same procedure as in Example 1 was conducted except that the acrylic resin solution obtained in Synthesis Example 6 was used and 3 g of a 5% toluene solution of N, N, N′N′-tetraglycidyl-m-xylenediamine was used as a curing agent. A pressure-sensitive adhesive was obtained and evaluated in the same manner as in Example 1.

[Example 7]
As an acrylic resin solution, a pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that 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 and used. Evaluation was performed in the same manner as in Example 1.

[Example 8]
A pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that the acrylic resin solution obtained in Synthesis Example 7 was used, and evaluated in the same manner as in Example 1.

[Example 9]
A pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that the acrylic resin solution obtained in Synthesis Example 7 was used and 6.66 g of a 30% aqueous solution of lithium perchlorate was used, and evaluation was performed in the same manner as in Example 1. .

[Comparative Examples 1 and 4]
Using each acrylic resin solution obtained in Synthesis Examples 8 and 3, a pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that a 30% aqueous solution of lithium perchlorate was not blended, and evaluated in the same manner as in Example 1. .

[Comparative Example 2]
A pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that the acrylic resin solution obtained in Synthesis Example 8 was used, and evaluated in the same manner as in Example 1.

[Comparative Example 5]
A pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that the acrylic resin solution obtained in Synthesis Example 2 was used and no curing agent was blended, and evaluation was performed in the same manner as in Example 1.

[Comparative Example 6]
A pressure-sensitive adhesive was obtained in the same manner as in Example 1 except that 1 g of lithium perchlorate was blended without dissolving in water, using the acrylic resin solution obtained in Synthesis Example 7, and evaluated in the same manner as in Example 1. did. In addition, when the lithium perchlorate was added and stirred, the temperature of the resin solution increased by 2 ° C., suggesting the danger of industrialization.

As described above, according to the present invention, it is possible to safely produce a solvent-type antistatic acrylic pressure-sensitive adhesive, and the resulting pressure-sensitive adhesive has surface resistance (conductivity), transparency, and removability. It turns out that it is excellent.
On the other hand, since the adhesive shown in Comparative Examples 1 and 4 does not contain an ionic compound, it has good removability and transparency, but has no conductivity. Since the pressure-sensitive adhesive shown in Comparative Example 2 does not have an alkylene oxide chain, the ionic compound does not dissolve and aggregates, resulting in poor transparency and surface resistance. Since the pressure-sensitive adhesive shown in Comparative Example 3 did not contain a hydroxyl group-containing monomer, the crosslinking effect by the curing agent was not obtained, and the removability was poor. Since the pressure-sensitive adhesive shown in Comparative Example 5 did not use a curing agent at all, the cohesive force was insufficient and the removability was poor. Although Comparative Example 6 has no problem in performance, it is not preferable because of its danger in the manufacturing process.

Schematic cross section showing a state in which an antistatic pressure-sensitive adhesive film according to the present invention comprising a PET film substrate and an antistatic acrylic pressure-sensitive adhesive layer carried on one surface thereof is attached to a polarizing plate with an antistatic acrylic pressure-sensitive adhesive layer FIG. It is typical sectional drawing which shows the state which affixed the antistatic adhesive film by this invention which provided the antistatic acrylic adhesive layer on both surfaces of a PET film base material to a polarizing plate by one antistatic acrylic adhesive layer. An antistatic pressure-sensitive adhesive film according to the present invention in which an antistatic coating agent layer is provided on one surface of a PET film substrate and an antistatic acrylic pressure-sensitive adhesive layer is supported thereon is polarized by the antistatic acrylic pressure-sensitive adhesive layer. FIG. 4 is a schematic cross-sectional view showing a state of being attached to a plate 3. An antistatic pressure-sensitive adhesive film according to the present invention in which an antistatic acrylic pressure-sensitive adhesive layer is provided on one surface of a PET film substrate and an antistatic coating agent layer is provided on the opposite surface is polarized by the antistatic acrylic pressure-sensitive adhesive layer. FIG. 4 is a schematic cross-sectional view showing a state of being attached to a plate 3.

Explanation of symbols

1: Plastic film substrate (PET)
2: Antistatic acrylic adhesive layer 3: Polarizing plate 4: Antistatic coating agent layer

Claims (9)

  A solvent-type antistatic acrylic pressure-sensitive adhesive characterized by mixing a solution of an acrylic copolymer (A) having a hydroxyl group and an alkylene oxide chain in the side chain, an aqueous solution of an ionic compound (B), and a curing agent (C). Manufacturing method.   The method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to claim 1, wherein the alkylene oxide chain is an ethylene oxide chain.   The method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to claim 1 or 2, wherein the acrylic copolymer (A) has a weight average molecular weight of 50,000 to 1,000,000.   4. The solvent-type antistatic acrylic according to claim 1, wherein the ionic compound (B) is 0.01 to 30 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). A method for producing an adhesive.   The method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the ionic compound (B) is an inorganic salt.   The acrylic copolymer (A) is obtained by subjecting a monomer having an alkylene oxide chain to copolymerization, and has an alkylene oxide chain in a total of 100% by weight of the monomers constituting the acrylic copolymer (A). 6. The method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to claim 1, wherein the monomer is 1 to 60% by weight.   The method for producing a solvent-type antistatic acrylic pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the curing agent (C) is a trifunctional isocyanate compound and / or a polyfunctional epoxy compound.   A solvent-type antistatic acrylic pressure-sensitive adhesive obtained by the production method according to claim 1. A protective film for an optical member, wherein an adhesive layer formed from the solvent-type antistatic acrylic adhesive according to claim 8 is laminated on at least one surface of a plastic film substrate.

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