KR100768745B1 - Adhesive film and polarizing plate containing the same - Google Patents

Abstract

 The present invention provides a pressure-sensitive adhesive film formed on one side, wherein the pressure-sensitive adhesive layer comprises a polar compound each containing one or more ester groups and alkylene oxide groups in the molecule; Acrylic copolymers; And it provides an adhesive film which is an adhesive composition comprising a metal salt compound.

The pressure-sensitive adhesive film according to the present invention provides excellent peeling force, appearance and antistatic performance while using only a small amount of additives, and the polarizing plate having the pressure-sensitive adhesive film can suppress a change in liquid crystal alignment due to static electricity even in a high speed peeling process. .

Description

Adhesive film and polarizing plate having same {Adhesive film and polarizing plate containing the same}

1 is a schematic diagram of an adhesive film 100 according to an embodiment of the present invention.

2 is a schematic diagram of an iodine-based polarizing plate 200 with an adhesive film according to an embodiment of the present invention.

3 is a schematic diagram of an iodine-based polarizing plate 300 that has been treated with anti-corrosion with an adhesive film according to an embodiment of the present invention.

4 is a schematic diagram illustrating a method of measuring a peeling electrification voltage (constant voltage) generated during peeling of an adhesive film according to an embodiment of the present invention.

<Description of Symbols Used in Drawings>

1: surface treatment layer 2: antistatic treatment layer

3: Base film 4: Acrylic adhesive with antistatic function

5: Release film 6: Protective film (TAC film)

7: polarizing film (PVA film) 8: adhesion layer

9: release film 10: anti-glare layer

11: glass substrate 12: peeling large-voltage (constant voltage) measuring sensor

1 to 4: adhesive film 6 to 8: polarizing plate

8 to 10: antiglare polarizer

100: adhesive film (including release film)

200: polarizing plate (including adhesive film and release film)

300: anti-glare polarizing plate (including adhesive film and release film)

The present invention relates to an adhesive film having an adhesive layer having an antistatic function on one side of a substrate, and a polarizing plate having the adhesive film.

Recently, the demand for liquid crystal displays (LCDs) has grown remarkably due to the spread of computers and the expansion of the market due to the multifunctionalization of mobile phones. In addition, high-density packaging technology is progressing to realize thinning and miniaturization, while LCD screens are becoming larger and wider. Major LCD manufacturers have been focusing on producing small panels of 20 inches or less so far, but have recently been actively using new technology to expand the product range to 20-inch and larger sizes. In particular, as the size of LCDs increases, a high-speed peeling process of peeling a liquid crystal protective adhesive film from a polarizing plate at a speed of 30 m to 50 m in 60 seconds has been used in order to improve productivity in manufacturing a liquid crystal display. In such a high-speed peeling process, static electricity is generated when the adhesive film is peeled off. Thus, the generated static electricity affects the alignment of the liquid crystal in the liquid crystal display to which the polarizer is attached, thereby causing a defect.

The generation of static electricity can be suppressed by forming an antistatic layer on the outer surface of the adhesive film or by forming an antistatic layer between the pressure-sensitive adhesive of the adhesive film and the base film, there is a problem that does not prevent the generation of static electricity. Therefore, in order to fundamentally suppress static electricity generation, it is preferable to give an antistatic function to the pressure-sensitive adhesive of the pressure-sensitive adhesive film.

For this purpose, generally, the method of adding the electrically conductive metal powder or the substance which has conductive components, such as a carbon particle, in the adhesive of an adhesive film is performed. However, when the metal powder or the carbon particles are added, a large amount of the metal powder or the carbon particles should be added in order to give the antistatic performance, thereby causing a problem that may lower the transparency of the adhesive film. On the other hand, there is also a method of improving the antistatic performance of the pressure-sensitive adhesive by adding a phthalate-based plasticizer inside the pressure-sensitive adhesive. However, in order to give a satisfactory antistatic function, an excess of 50 parts by weight or more may be added based on 100 parts by weight of the acrylic pressure sensitive adhesive, and in this case, it may result in deterioration of the substrate adhesiveness and adhesive performance of the pressure sensitive adhesive. And when using less than 10 parts by weight in order to maintain the substrate adhesion and adhesion performance can not have an antistatic function.

In addition to the above method, there are methods for adding various low molecular weight surfactants to the pressure-sensitive adhesive, but in this case, the compatibility with the resin is poor and the antistatic effect is not satisfactory, and the pressure-sensitive adhesive moves to the surface of the adherend. The phenomenon in which the adhesive is transferred to the surface also appears. In addition, since the antistatic performance is easy to depend on the external environment such as temperature, humidity, it is difficult to obtain a product having uniform characteristics.

More specifically, in the prior art of an adhesive film having an antistatic function, Japanese Patent Application Laid-Open No. Hei 5-140519 has flexibility by adding ethylene oxide-modified dioctyl-based plasticizer inside the pressure-sensitive adhesive of the pressure-sensitive adhesive film to suppress static electricity generation. Attempts have been made. However, it is difficult to fundamentally suppress static electricity generated when the pressure-sensitive adhesive film is peeled off at a high speed from the polarizing plate only by adding the plasticizer as described above. Japanese Patent No. 3190743 discloses an attempt to suppress static electricity by combining 5 to 40 parts by weight of a polyether polyol compound and an alkyl metal salt based on 100 parts by weight of an acrylic pressure-sensitive adhesive composition as an adhesive composition of an adhesive sheet. However, when the polyether polyol compound is used in the above weight parts, there is an effect of suppressing the generation of static electricity, but the surface migration of the polyether polyol compound increases, which may significantly reduce the peeling force or cause a problem of transferring to the surface of the adherend.

Therefore, there is still a need for a pressure-sensitive adhesive film that can effectively suppress the generation of static electricity during high-speed peeling without side effects such as a reduction in peel force and a decrease in film transparency as in the prior art.

The first technical problem to be achieved by the present invention is to provide an antistatic function pressure-sensitive adhesive film that can suppress the generation of static electricity during high-speed peeling without the above side effects.

The second technical problem to be achieved by the present invention is to provide a polarizing plate having the adhesive film.

The present invention to achieve the first technical problem,

The pressure-sensitive adhesive layer is formed on one side, the pressure-sensitive adhesive layer is

Polar compounds each containing at least one ester group and alkylene oxide group in a molecule thereof;

Acrylic copolymers; And,

Metal salt compounds;

It provides an adhesive film comprising a.

In the pressure-sensitive adhesive film according to an embodiment of the present invention, the compound including one or more ester groups and alkylene oxide groups in the molecule is preferably a compound represented by the following formula (1).

<Formula 1>

In Chemical Formula 1,

R ₁ is a linear or branched alkyl group having 1 to 20 carbon atoms, R ₂ is a linear or branched alkylene group having 2 to 20 carbon atoms, X is hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, or -C (= O) R ₃ , R ₃ is a linear or branched alkyl group having 1 to 20 carbon atoms, and n is 1 to 120.

In the pressure-sensitive adhesive film according to an embodiment of the present invention, it is more preferable that the compound represented by Chemical Formula 1 is represented by the following Chemical Formula 2.

<Formula 2>

In Chemical Formula 1,

R ₁ is a linear or branched alkyl group having 1 to 20 carbon atoms, X is hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, or -C (= 0) R ₃ , and R ₃ is a linear or branched alkyl group having 1 to 20 carbon atoms It is a branched alkyl group, n is 1-120.

In the pressure-sensitive adhesive film according to an embodiment of the present invention, it is preferable that the pressure-sensitive adhesive layer further includes a crosslinking agent.

In the pressure-sensitive adhesive film according to an embodiment of the present invention, 3 to 8 parts by weight of the polar compound including one or more ester groups and alkylene oxide groups in the molecule based on 100 parts by weight of the acrylic copolymer, It is preferable to contain 0.01-5 weight part of metal salt compounds.

In the pressure-sensitive adhesive film according to another embodiment of the present invention, it is preferable that the pressure-sensitive adhesive layer further includes 1 to 10 parts by weight of the crosslinking agent based on 100 parts by weight of the acrylic copolymer.

In the pressure-sensitive adhesive film according to an embodiment of the present invention, the molecular weight of the polar compound including one or more ester groups and alkylene oxide groups in the molecule is preferably 100 to 4000.

In the pressure-sensitive adhesive film according to an embodiment of the present invention, the metal salt compound is one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ and Ce ^{2+ Cl -, Br -, (CF} 3 SO 2) 2 N -, ClO 4 -, BF 4 -, PF 6 -, NO 3 - and at least one metal salt consisting of one anion selected from the group consisting of CO ₃ ^2- It is preferable that it is a compound.

When peeling the adhesive film according to an embodiment of the present invention from the adherend, the peeling electrification voltage is preferably -0.5kV to + 0.5kV.

The present invention to achieve the second technical problem,

It provides the polarizing plate provided with the adhesive film which concerns on the above.

The pressure-sensitive adhesive film according to the present invention provides an excellent peel force, appearance and antistatic performance while using only a small amount of additives, unlike a conventional pressure-sensitive adhesive film in which peeling force is reduced by using an excessive amount of additives and transparency of the film is reduced. The polarizing plate provided with an adhesive film can suppress the liquid-crystal orientation change by static electricity also in a high speed peeling process.

Hereinafter, the present invention will be described in more detail.

The present invention provides a pressure-sensitive adhesive film formed on one side, wherein the pressure-sensitive adhesive layer comprises a polar compound each containing one or more ester groups and alkylene oxide groups in the molecule; Acrylic copolymers; And it provides an adhesive film which is an adhesive composition comprising a metal salt compound. As shown in FIG. 1, the pressure-sensitive adhesive film 100 of the present invention basically includes only the base film 3 and the pressure-sensitive adhesive layer 4, but improves the antistatic function of the pressure-sensitive adhesive film and compatibility with the adherend. It is possible to have a configuration of the surface treatment layer 1, the antistatic treatment layer 2, the base film 3, the pressure-sensitive adhesive layer 4 and the release film (5).

First, the antistatic function of the adhesive film will be described. The following description of the antistatic function is for the purpose of understanding the present invention, and the scope of the present invention is not limited to the scope of the following description.

The antistatic function of the adhesive film is obtained by the polar compound and the metal salt compound. More specifically, a complex is formed with a cation of a metal salt to which a polar functional group of a polar compound including at least one ester group and an alkylene oxide group in the molecule is added together. Such a complex is dispersed while maintaining a physical crosslinked state inside the pressure-sensitive adhesive composition to impart electrical conductivity to the pressure-sensitive adhesive composition. That is to form a solid electrolyte (solid electrolyte). The pressure-sensitive adhesive composition having such electrical conductivity is very excellent in the ability of discharging the static electricity generated in the pressure-sensitive adhesive generated during the pressure-sensitive adhesive manufacturing process inside the pressure-sensitive adhesive to the air or through ground. Therefore, the static electricity generated during the peeling process of the adhesive film can be effectively reduced to lower the peel electrification voltage to a very low value. This peeling electrification voltage can also be expressed as a decrease in the accumulated charge amount.

The polar compound including one or more ester groups and alkylene oxide groups in the molecule used in the present invention may be represented by the following formula (1).

 <Formula 1>

In Formula 1, R ₁ is a linear or branched alkyl group having 1 to 20 carbon atoms, R ₂ is a linear or branched alkylene group having 2 to 20 carbon atoms, X is hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms Or -C (= 0) R ₃ , R ₃ is a linear or branched alkyl group having 1 to 20 carbon atoms, and n is 1 to 120.

In addition, the compound represented by Formula 1 may be more preferably represented by the following formula (2).

<Formula 2>

In Formula 1, R ₁ is a linear or branched alkyl group having 1 to 20 carbon atoms, X is hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, or -C (= O) R ₃ , R ₃ is 1 carbon Is a linear or branched alkyl group of 20 to 20, n is 1 to 120.

Most preferably, the compound represented by Formula 2 may be an alkylene oxide, polyethylene glycol ester, fatty acid alkyl ester of polyethylene glycol, carboxylic acid ester of polyethylene glycol ( Carboxylic acid ester of polyethylene glycol) may be used.

In addition, the pressure-sensitive adhesive layer in the pressure-sensitive adhesive film preferably further comprises a crosslinking agent. The crosslinking agent crosslinks the acrylic copolymer to increase the adhesion. The details of the crosslinking agents will be mentioned again in the content section below.

Next, the acrylic copolymer used in the present invention is not particularly limited, and any acrylic copolymer may be used as long as it can be used in the adhesive in the art. However, it is preferable to use the acrylic copolymer which has a hydroxyl group in consideration of the peeling force of an adhesive and a polarizing plate. The acrylic copolymer of the present invention is obtained by copolymerizing 70 to 99 parts by weight of a (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms and a monomer having 1 to 30 parts by weight of a crosslinkable hydroxyl group as a whole. It is preferable.

The (meth) acrylic acid ester monomer used in the acrylic copolymer of the present invention preferably has an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 2 to 8 carbon atoms.

When the alkyl group in the (meth) acrylic acid ester monomer is too long, the cohesive force of the pressure-sensitive adhesive is low, so to maintain the cohesive force under high temperature, it is preferable to select the carbon number of the alkyl group in the range of 1 to 12. Specific examples of the (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, Or isononyl (meth) acrylate, and the like, or these may be used alone or in combination of two or more thereof.

In addition, in order to control the glass transition temperature (T _g ) of the pressure-sensitive adhesive or impart other functional properties in the production of the acrylic copolymer of the present invention, it is also possible to further use other monomers, such as acrylonitrile, (Meth) acrylamide, N-methylacrylamide, styrene, methylstyrene, vinyltoluene, glycidyl (meth) acrylate, vinyl acetate, etc. are mentioned.

The monomer including the crosslinkable hydroxyl group provides a cohesive force or an adhesive strength by chemical bonding so that the cohesive force of the pressure-sensitive adhesive is not destroyed in a high temperature or high humidity condition by reacting with the crosslinking agent. The monomer containing the crosslinkable hydroxyl group is preferably a vinyl monomer and an acrylic monomer, or a mixture thereof.

As an example of the monomer containing the said crosslinkable hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate 2-hydroxyethylene glycol ( There exists a monomer containing hydroxyl groups, such as a meth) acrylate and 2-hydroxypropylene glycol (meth) acrylate. Monomers containing carboxyl groups such as acrylic acid, methacrylic acid, acrylic acid duplexes, itaconic acid, maleic acid and maleic anhydride may also be used.However, monomers having a carboxyl group form a strong bonding force with the surface of the polarizing plate to provide a very high peeling force. As it rises higher, a high load occurs when peeling off the adhesive film, which may lower productivity. Therefore, a monomer including a hydroxyl group should be used. Monomers containing the hydroxyl group may be used alone or in combination.

It is preferable to use 1-30 weight part of monomers containing the said hydroxyl group. When the content of the monomer containing a crosslinkable hydroxyl group is less than 1 part by weight, cohesive failure is likely to occur at high temperature or high humidity conditions, and the effect of improving adhesion is reduced. When the content of the monomer exceeds 30 parts by weight, the compatibility decreases, causing surface migration to occur severely, and the stress relaxation ability is reduced by decreasing the flow characteristics and increasing the cohesive force.

The copolymer is preferably used after sufficiently removing the components causing bubbles such as volatile components, reaction residues therein. When the crosslinking density or molecular weight of the copolymer is too low and the elastic modulus of the pressure-sensitive adhesive composition including the copolymer is too low, small bubbles existing between the polarizing plate and the pressure-sensitive adhesive layer in a high temperature state become large to form scattering bodies in the pressure-sensitive adhesive layer. . In addition, when the pressure-sensitive adhesive composition having a high elastic modulus is used for a long time, the phenomenon of lifting occurs in the terminal portion of the pressure-sensitive adhesive sheet due to excessive crosslinking reaction. In addition, since the viscoelastic properties of the pressure-sensitive adhesive mainly depend on the molecular weight, molecular weight distribution, or molecular structure of the copolymer, and in particular, it is determined by the molecular weight, the weight average molecular weight of the copolymer used in the present invention is preferably 200,000 to 1000,000. It can be prepared through conventional radical copolymerization mechanism.

The polymerization method of the copolymer used in the present invention is not particularly limited, and can be produced by polymerization methods such as solution polymerization, photopolymerization, bulk polymerization, suspension polymerization, emulsion polymerization, and the like. It is preferable to superpose | polymerize by the easy solution polymerization method. At this time, polymerization temperature is 50-140 degreeC, and it is preferable to add an initiator in the state in which monomer was mixed uniformly.

It is preferable that the adhesive composition contained in the adhesive film of this invention contains 3-8 weight part of polar compounds based on 100 weight part of said acrylic copolymers. If the content of the polar compound is less than 3 parts by weight, it does not form a complex with the alkali metal salt sufficiently to prevent the antistatic performance. If the content is more than 8 parts by weight, the surface of the polar compound increases, the antistatic effect is reduced and the inherent characteristics of the pressure-sensitive adhesive The problem that the adhesive force falls is generated. In addition, the content of the metal salt compound used in the pressure-sensitive adhesive composition of the present invention is preferably 0.01 to 5.0 parts by weight, more preferably 0.1 to 1.0 parts by weight based on 100 parts by weight of the acrylic copolymer. If the content of the metal salt is less than 0.01 parts by weight, a sufficient static reduction effect is not obtained. If the content is more than 5.0 parts by weight, the solubility of the metal salt is exceeded in the solvent, so that the metal salt is precipitated in a solid state, and thus the desired antistatic function cannot be obtained. It is not possible to obtain a uniform appearance after applying the adhesive.

As mentioned above, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer of the present invention preferably further includes a multifunctional crosslinking agent. As such a crosslinking agent, an isocyanate-based, epoxy-based, aziridine-based, metal chelate-based crosslinking agent, etc. may be used. Among them, the use of isocyanate is easy. Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoform diisocyanate, tetramethyl xylene diisocyanate, naphthalene diisocyanate and polyols such as trimethylolpropane and And reactants.

In addition, as the epoxy-based crosslinking agent, ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N, N-tetraglycidyl ethylenediamine, glycerin diglycidyl ether Etc. can be mentioned. As the aziridine-based crosslinking agent, N, N-toluene-2,4-bis (1-aziridinecarboxide), N, N-diphenylmethane-4,4`-bis (1-aziridinecarboxide) , Triethylenemelamine, bisisoprotaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide and the like. Examples of the metal chelate crosslinking agent include compounds in which polyvalent metals such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and vanadium are coordinated with acetylacetone or ethyl acetoacetate. The manufacturing method of the adhesive composition of this invention is not specifically limited, It can obtain by mixing the above-mentioned acrylic copolymer and a crosslinking agent by a conventional method.

At this time, the multifunctional crosslinking agent may be uniformly coated only when the functional group crosslinking reaction of the crosslinking agent is hardly generated in the compounding process for forming the adhesive layer. After the coating operation is completed, the cross-linking structure is formed through the drying and aging process to obtain an elastic and cohesive strong adhesive layer. At this time, by the strong cohesive force of the pressure-sensitive adhesive, adhesive properties such as durability, reliability, and cutability of the pressure-sensitive adhesive film are improved.

When considering the optimal physical balance, the pressure-sensitive adhesive composition included in the pressure-sensitive adhesive film according to the present invention preferably further includes 1 to 10 parts by weight of the crosslinking agent based on 100 parts by weight of the copolymer. The crosslinking density is suitably in the range of 5 to 95%. The above-mentioned crosslinking density refers to a numerical value obtained by weight percent of the amount of the crosslinked structure that is not dissolved in a solvent through a gel content measurement method of a generally known acrylic pressure sensitive adhesive. At this time, if the crosslinking density of the pressure-sensitive adhesive is less than 5%, the cohesive force of the pressure-sensitive adhesive is lowered, and problems may occur in the adhesive durability such as bubbles or peeling, and if it exceeds 95%, the durability reliability such as lifting is weak. have.

Therefore, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer in the pressure-sensitive adhesive film of the present invention, based on 100 parts by weight of the acrylic copolymer, 3 to 8 parts by weight of a polar compound each containing at least one ester group and an alkylene oxide group in the molecule, metal salt compound 0.01 It is preferred to include from 5 parts by weight to 1 to 10 parts by weight of the crosslinking agent.

In addition, the present invention may be mixed with the acrylic low molecular weight, epoxy resin and curing agent for a specific purpose, UV stabilizer, antioxidant, colorant, reinforcing agent, filler, antifoaming agent, surfactant, plasticizer and the like according to the general purpose It may be added as appropriate.

As the base film 3 used in the adhesive film 100 of the present invention, a biaxially stretched transparent polymer film is used, and a biaxially stretched polyethylene terephthalate film is suitable in consideration of heat resistance and transparency. The thickness of the film used is not particularly limited, but 25 to 50 microns (µm) are suitable. The adhesive film includes an adhesive layer 4 formed on one side of the base film 3.

In the present invention, the method of forming the pressure-sensitive adhesive layer on one side of the base film is not particularly limited, and a method of applying and drying the pressure-sensitive adhesive using a bar coater or the like directly on the surface of the base film, or excellent release property of the pressure-sensitive adhesive once After apply | coating to a peelable base material surface and drying, the method of transferring the adhesive layer formed in this peelable base material surface to the base film surface, and then aging may be applied.

Next, the polar compound including one or more ester groups and alkylene oxide groups in the molecule used in the pressure-sensitive adhesive composition included in the pressure-sensitive adhesive film of the present invention preferably has a weight average molecular weight (M _w ) of 100 to 4,000, More preferably, it is 500-2,000. When the polar compound having a weight average molecular weight of 100 or less is used, the polar compound which does not form a complex with the dissociated alkali metal salt metal ion migrates to the pressure-sensitive adhesive layer surface, and during the aging process, the polar compound is accelerated to the surface. After peeling of the adhesive film on a polarizing plate, a low molecular weight substance is transcribe | transferred on the surface of a to-be-adhered body, resulting in the contamination of the surface of a to-be-adhered body (for example, a polarizing plate). On the other hand, when the weight average molecular weight of the polar compound is 4,000 or more, the phenomenon of transition to the surface of the adherend is reduced, but when added to the adhesive copolymer, the viscosity of the copolymer is increased, and the mixed viscosity with the adhesive copolymer Not easy. Therefore, workability may be reduced, resulting in uneven coating, resulting in a problem that the thickness of the pressure-sensitive adhesive layer is not constant.

Next, in the pressure-sensitive adhesive composition included in the pressure-sensitive adhesive film of the present invention, examples of the metal salt compound include alkali metal salts and alkaline earth metal salt compounds, and the metal salt compound that is easily dissociated in an ionic form in a solvent is more preferable, and the metal is dissociated. The smaller the ion radius and the smaller the dissociation energy group, the more preferable the ion is.

For example, as a cation constituting the metal salt compound, it is preferable to use a metal salt containing an alkali metal such as Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , and an alkali earth metal. As an anion corresponding to the cationic metal is _{^{Cl -, Br -, BF 4}} -, PF 6 -, ClO 4 -, NO 2 -, CO 3 2-, CF 3 SO 3 - and (CF ₃ SO _{2) 2} N ^- the inorganic and organic anions and the like.

Moreover, as another metal salt compound containing the said metal cation, the metal salt of the alkyl phosphate ester which is an anionic organic compound, the metal salt of polyoxyethylene alkyl ether phosphate ester, etc. are mentioned.

In the present invention, the pressure-sensitive adhesive film is preferably a peeling electrification voltage at −0.5 kV to 0.5 kV when peeled from the adherend. The numerical value is more preferably -0.2 to 0.2kV, and most preferably -0.1 to 0.1kV. If the absolute value of the peeling electrification voltage (constant voltage) generated on the surface of the adherend during peeling of the adhesive film during the liquid crystal display manufacturing process exceeds 0.5 kV, there is a problem that the defective rate such as element breakdown increases due to static electricity, thereby preventing the static electricity. It is hard to see that this is.

 The adhesive film of the present invention may also be provided with an additional layer through surface treatment or antistatic treatment. As shown in FIG. 1, the pressure-sensitive adhesive film of the present invention has a structure of a surface treatment layer 1, an anti-reflective treatment layer 2, a base film 3, an adhesive layer 4, and a release film 5. It is possible. Basically, the adhesive film of the present invention is composed of only the base film 3 and the pressure-sensitive adhesive layer 4, but by adding the other components, the antistatic function of the present invention and compatibility with the adherend can be improved. One embodiment of the adhesive film is described in more detail in Example 1.

The pressure-sensitive adhesive film using the acrylic pressure-sensitive adhesive composition having an antistatic function of the present invention can be used without limitation in the use of industrial sheets, in particular, pressure-sensitive adhesive sheets for electronic components, optical films and the like. Multilayer laminate products, ie general commercial adhesive sheet products, medical patches, heat activated pressure sensitive adhesives, and the like can be applied to the same application field. As described above, the pressure-sensitive adhesive film of the present invention has at least the polar compound and the metal salt, which is excellent in durability, reliability and adhesiveness, and at the same time has an antistatic function.

In another aspect, the present invention provides a polarizing plate (200, 300) having an adhesive film according to the above. One embodiment of the polarizer is shown in FIGS. 2 and 3. In the polarizing plate 200 illustrated in FIG. 2, a TAC film 6 as a protective film is disposed on both sides of a PVA film 7, which is a polarizing film, respectively, followed by an adhesive layer 8 for a polarizing plate and a release film 9 for a polarizing plate. Is placed. The adhesive film 1-4 shown in FIG. 1 is disposed on an upper end of the polarizer 200. The polarizer 300 shown in FIG. 3 differs from that in which the anti-glare layer 10 is additionally included in the polarizer 200 of FIG. 2. The polarizers 200 and 300 shown in FIGS. 2 and 3 are described in more detail in the peel versus voltage measurement experiment of the embodiment.

The polarizing plate provided with the adhesive film has a very low peeling electrification voltage even at a high speed of peeling and does not cause a problem such as a change in liquid crystal alignment due to static electricity. The polarizing plate having the adhesive film is not particularly limited and may include all kinds of polarizing plates used in the art. The polarizing plate generally has a structure in which two or more films are stacked instead of a single film. The form in which the polarizing film and the protective film are mainly overlapped forms the basic structure. Representative examples of the polarizing film include polyvinyl alcohol (hereinafter referred to as PVA) -iodine-based, PVA-dye-based, PVA-based polyvinylene-based PVA-based polarizing films, and polyene-based polarizing films. By the way, since most of the general-purpose polarizing films are weak in mechanical strength with respect to the transmission axial direction and easily shrink or degrade due to heat or moisture, a protective film for blocking the film from the outside is used. Representative examples of such a protective film include a cellulose triacetate (hereinafter referred to as TAC) film having a low birefringence and a good appearance.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, which are intended to help a specific understanding of the present invention, and the scope of the present invention is not limited by the Examples.

Preparation of Adhesive Film

Example 1

(1) Manufacture of Acrylic Copolymer

In a 1L reactor equipped with a refrigeration system for reflux of nitrogen gas and easy temperature control, 85 parts by weight of 2-ethylhexyl acrylate (2-EHA), 12 parts by weight of n-butyl acrylate (BA), 2 having a hydroxyl group After adding a monomer mixture composed of 3 parts by weight of hydroxyethyl acrylate (2-HEA), 100 parts by weight of ethyl acetate (EtAc) was added as a solvent. Then, after purging nitrogen gas for 1 hour to remove oxygen, it was maintained at 55 ℃. After the solution was homogeneous, 0.03 parts by weight of azobisisobutyronitrile (AIBN) diluted with 50% by weight of ethyl acetate was added to the reaction initiator. Then, the solution was reacted for 15 hours to prepare an acrylic copolymer.

(2) Mixing process

65 parts by weight of ethyl acetate (EAc), which is a solvent, was diluted with respect to 100 parts by weight of the acrylic copolymer prepared above, and 4.0 parts by weight of a fatty acid ester of carboxylic acid ester of polyethylene glycol, a metal salt compound. 0.5 parts by weight of phosphorus Li (CF ₃ SO ₂ ) ₂ N and ₂ parts by weight of isocyanate hexamethylene diisocyanate (HMDI) as a crosslinking agent were sequentially added thereto, followed by uniformly stirring to prepare an acrylic pressure-sensitive adhesive composition.

(3) coating process

The acrylic pressure-sensitive adhesive composition prepared above was coated on a biaxially stretched polyethylene terephthalate film having a thickness of 38 μm using a bar coater, and dried at 120 ° C. for 3 minutes to obtain a uniform adhesive layer having a thickness of 22 μm.

(4) plywood process

The pressure-sensitive adhesive film was prepared by coating the pressure-sensitive adhesive composition in the coating process and laminating with a 25 μm-thick silicone coated release base film on a biaxially stretched polyethylene terephthalate film having a pressure-sensitive adhesive layer having a thickness of 22 μm on the surface.

Example 2

An adhesive film was prepared in the same manner as in Example 1 except that 0.5 parts by weight of LiClO ₄ metal salt was added in the compounding process.

Example 3

An adhesive film was prepared in the same manner as in Example 1, except that 3 parts by weight of polyethylene glycol carboxylic acid ester (Carboxylic acid ester of Polyethylene Glycol) was added.

Example 4

A pressure-sensitive adhesive film was prepared in the same manner as in Example 1 except that 8 parts by weight of polyethylene glycol carboxylic acid ester (Carboxylic acid ester of Polyethylene Glycol) was added.

Example 5

An adhesive film was prepared in the same manner as in Example 1 except that 0.01 part by weight of Li (CF ₃ SO ₂ ) ₂ N was added.

Example 6

A pressure-sensitive adhesive film was prepared in the same manner as in Example 1 except that 5 parts by weight of Li (CF ₃ SO ₂ ) ₂ N was added.

Comparative Example 1

An adhesive film was prepared in the same manner as in Example 1 except that only the acrylic copolymer was used in the compounding process and the polar compound and the metal salt compound were not used in order not to impart an antistatic function to the adhesive.

Comparative Example 2

An adhesive film was prepared in the same manner as in Comparative Example 1 except for adding only 4.0 parts by weight of a polyethylene glycol carboxylic acid ester (Polyethylene Glycol) as a polar compound.

Comparative Example 3

A pressure-sensitive adhesive film was manufactured in the same manner as in Comparative Example 1 except that 0.5 parts by weight of Li (CF ₃ SO ₂ ) ₂ N was additionally added.

Comparative Example 4

In the same manner as in Example 1, except that 2 parts by weight of a polar compound, a polyethylene glycol carboxylic acid ester of Polyethylene Glycol, and 0.5 parts by weight of a Li (CF ₃ SO ₂ ) ₂ N metal salt were added. An adhesive film was made.

Comparative Example 5

In the same manner as in Example 1, except that 10 parts by weight of a polar compound, a polyethylene glycol carboxylic acid ester of Polyethylene Glycol, and 0.5 parts by weight of a Li (CF ₃ SO ₂ ) ₂ N metal salt were added. An adhesive film was made.

Comparative Example 6

In the same manner as in Example 1, except that 4 parts by weight of a polar compound, a polyethylene glycol carboxylic acid ester of Polyethylene Glycol, and 0.005 parts by weight of a Li (CF ₃ SO ₂ ) ₂ N metal salt were added. An adhesive film was made.

Comparative Example 7

In the same manner as in Example 1, except that 4 parts by weight of a polyethylene glycol carboxylic acid ester (Polyethylene Glycol) and 10 parts by weight of a Li (CF ₃ SO ₂ ) ₂ N metal salt were added during the compounding process. An adhesive film was made.

Comparative Example 8

An adhesive film was prepared in the same manner as in Example 1, except that only 10 parts by weight of a polyethylene glycol carboxylic acid ester (Polyethylene Glycol), a polar compound, and no metal salt were added.

Polarizing plate manufacturing and peeling voltage measurement (constant voltage)

After leaving the pressure-sensitive adhesive film prepared in Examples 1-6 and Comparative Examples 1-8 at 64 ° C. for 64 hours to sufficiently mature the pressure-sensitive adhesive layer, the peelable base film having excellent releasability was peeled off and the thickness was 185 μm. In order to give an iodine polarizing plate or an anti-glare function, a specimen (20 cm × 30 cm) was manufactured by plywood with an iodine polarizing plate coated with an anti-glare treatment layer. After allowing it to stand for 24 hours, the pressure-sensitive adhesive film was peeled off from the polarizing plate at a speed of 30 m / min. At this time, the amount of constant voltage generated on the surface of the polarizing plate was measured using an electrostatic measuring sensor (STATIRON-M2). The measuring method is schematically illustrated in FIG. 4.

Manufacturing polarizer and measuring adhesive force (low peel force)

After leaving the pressure-sensitive adhesive film prepared in Examples 1-6 and Comparative Examples 1-8 at 64 ° C. for 64 hours to sufficiently mature the pressure-sensitive adhesive layer, the peelable base film having excellent releasability was peeled off and the thickness was 185 μm. In order to give an iodine polarizing plate or an anti-glare function, a specimen (20 cm × 30 cm) was manufactured by plywood with an iodine polarizing plate coated with an anti-glare treatment layer. After allowing to stand for 24 hours, the pressure-sensitive adhesive film was peeled off from the polarizing plate at a speed of 0.3 m / min. At this time, peeling force was measured and it determined as follows.

○: 3gf ~ 10gf

× 2gf or less

(When 2gf or less, there is no adhesive force, so the phenomenon of lifting of the adhesive film and the polarizing plate occurs)

Manufacturing polarizer and measuring adhesive force (high speed peeling force)

After leaving the pressure-sensitive adhesive film prepared in Examples 1-6 and Comparative Examples 1-8 at 64 ° C. for 64 hours to sufficiently mature the pressure-sensitive adhesive layer, the peelable base film having excellent releasability was peeled off and the thickness was 185 μm. In order to give an iodine polarizing plate or an anti-glare function, a specimen (20 cm × 30 cm) was manufactured by plywood with an iodine polarizing plate coated with an anti-glare treatment layer. After allowing it to stand for 24 hours, the pressure-sensitive adhesive film was peeled off from the polarizing plate at a speed of 30 m / min. At this time, peeling force was measured and it determined as follows.

○: 120gf ~ 150gf

×: 50gf or less or 300gf or more

(When 50gf or less, there is no adhesive force, so the lifting phenomenon of the adhesive film and the polarizing plate occurs, and when 300gf or more, the adhesive force is very high and high load occurs when peeling the adhesive film from the polarizing plate.)

Adhesive film coating appearance evaluation

The pressure-sensitive adhesive coating appearance of the pressure-sensitive adhesive films prepared in Examples 1-6 and Comparative Examples 1-8 was determined.

○: Transparent, without bubbles, streaks or stains

△: Some bubbles, streaks, stains, etc., but transparency is good

×: bubbles, streaks, stains, etc., poor transparency

Peeling Constant Voltage (kV) Low speed peeling force (adhesive force) High speed peeling force (adhesive force) Coating appearance Iodine Polarizing Plate Anti-glare iodine polarizer Example 1 0.1 0.1 ○ ○ ○ Example 2 0.1 0.1 ○ ○ ○ Example 3 0.2 0.3 ○ ○ ○ Example 4 0.4 0.5 ○ ○ ○ Example 5 1.0 1.2 ○ ○ ○ Example 6 0.1 0.2 ○ ○ △ Comparative Example 1 6.0 6.0 ○ ○ ○ Comparative Example 2 2.0 2.5 ○ ○ ○ Comparative Example 3 3.0 3.0 ○ ○ ○ Comparative Example 4 1.2 2.0 ○ ○ ○ Comparative Example 5 1.0 1.5 × (none) × (high) ○ Comparative Example 6 1.0 1.5 ○ ○ △ Comparative Example 7 0.4 1.0 ○ ○ X (stripes) Comparative Example 8 1.5 2.0 × (none) × (high) ○

In the case of the polarizing plate, the peeling constant voltage generated when the adhesive film was peeled off at a high speed was very low, and the coating appearance such as transparency was excellent, and the low peeling force and the high peeling force were very good. The pressure-sensitive adhesive layer of the above examples contained 3 to 8 parts by weight of the polar compound and 0.01 to 5 parts by weight of the metal salt compound based on 100 parts by weight of the acrylic copolymer. However, in the case of the polarizing plate with the pressure-sensitive adhesive film prepared in Comparative Examples 1-8, the peeling constant voltage is very high, the low speed peeling force is low, the high speed peeling force is very high, or the coating appearance is very bad. It did not satisfy the required physical properties.

This difference in physical properties is believed to be due to the optimization of the composition of the pressure-sensitive adhesive composition so as to have excellent antistatic performance and a good peeling force at the same time in the adhesive film of the present invention.

The adhesive film according to the present invention provides an excellent appearance such as excellent peeling force, transparency and excellent antistatic performance while using only a small amount of additives, and the polarizing plate having the adhesive film has a change in liquid crystal orientation due to static electricity even at a high speed peeling process. Can be suppressed.

Claims (10)

As the pressure-sensitive adhesive layer formed on one side A polar compound including one or more ester groups and alkylene oxide groups in the molecule, respectively; Acrylic copolymers; And, Metal salt compounds; Adhesive film comprising a. According to claim 1, wherein the compound containing at least one ester group and an alkylene oxide group in the molecule is represented by the formula (1): <Formula 1>

In Chemical Formula 1, R ₁ is a linear or branched alkyl group having 1 to 20 carbon atoms, R ₂ is a linear or branched alkylene group having 2 to 20 carbon atoms, X is hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, or -C (= O) R ₃ , R ₃ is a linear or branched alkyl group having 1 to 20 carbon atoms, and n is 1 to 120. The pressure-sensitive adhesive film of claim 1, wherein the compound including one or more ester groups and alkylene oxide groups in the molecule is represented by the following Chemical Formula 2. <Formula 2>

In Chemical Formula 1, R ₁ is a linear or branched alkyl group having 1 to 20 carbon atoms, X is hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, or -C (= 0) R ₃ , and R ₃ is a linear or branched alkyl group having 1 to 20 carbon atoms It is a branched alkyl group, n is 1-120. The pressure-sensitive adhesive film of claim 1, wherein the pressure-sensitive adhesive layer further comprises a crosslinking agent. According to claim 1, wherein the pressure-sensitive adhesive layer comprises 3 to 8 parts by weight of a polar compound containing at least one ester group and an alkylene oxide group in the molecule based on 100 parts by weight of the acrylic copolymer, 0.01 to 5 parts by weight of a metal salt compound Adhesive film characterized in that. The pressure-sensitive adhesive film of claim 5, wherein the pressure-sensitive adhesive layer further comprises 1 to 10 parts by weight of the crosslinking agent based on 100 parts by weight of the acrylic copolymer. The pressure-sensitive adhesive film according to claim 1, wherein the molecular weight of the polar compound including one or more ester groups and alkylene oxide groups in the molecule is 100 to 4000, respectively. The method of claim 1, wherein the metal compound is a ^{Li +, Na +, K +} , Mg 2+, Ca 2+, a cation selected from the group consisting of Ba ²⁺ and Ce ²⁺ and Cl ^-, Br ^-, ( ^{_{CF 3 SO 2) 2 N -}} , ClO 4 -, BF 4 -, PF 6 -, NO 3 - and CO ₃ ^2- group in which the adhesive characterized in that the selected one of at least one metal salt consisting of an anion of a compound consisting of at film. The pressure-sensitive adhesive film according to claim 1, wherein the peeling electrification voltage is -0.5 kV to 0.5 kV when the pressure-sensitive adhesive film is peeled off the adherend. The adhesive film in any one of Claims 1-9 was provided. The polarizing plate characterized by the above-mentioned.

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