KR101084033B1 - Acrylic pressure sensitive adhesive composition and surface protective film using them - Google Patents

Abstract

The present invention relates to an acrylic pressure-sensitive adhesive composition and a surface protective film using the same.

The acrylic pressure-sensitive adhesive composition of the present invention contains 0.01 to 0.5 parts by weight of the hydrophilic compound with respect to 100 parts by weight of the acrylic copolymer, and by controlling the physical properties by optimizing the content of the hydrophilic compound, to the adherend properties in the heat and humidity conditions Provides an acrylic pressure-sensitive adhesive composition having little effect or curling, excellent in stain resistance to an adherend, excellent in peelability and antistatic property when peeling, and the present invention contains the acrylic pressure-sensitive adhesive composition on at least one side of the base film. A pressure-sensitive adhesive layer is laminated to provide a surface protection film, and is effective in preventing curling of adherends under moisture and heat conditions, and thus is useful as a surface protection film for polarizing plates of liquid crystal displays.

Adhesive, Polarizing Plate, Protective Film, Curl, Hydrophilic, Antistatic, Alkylene Oxide

Description

ACRYLIC PRESSURE SENSITIVE ADHESIVE COMPOSITION AND SURFACE PROTECTIVE FILM USING THEM}

The present invention relates to an acrylic pressure-sensitive adhesive composition and a surface protective film using the same, and more particularly, the present invention is to control the physical properties by containing a hydrophilic compound in the acrylic copolymer in an optimum content, thereby affecting the adherend properties in the heat and humidity conditions The present invention relates to an acrylic pressure-sensitive adhesive composition having little or no curl and excellent in fouling resistance to an adherend, reliable peeling force, and antistatic property when peeling, and a surface protective film using the same.

A surface protective film is generally used for the purpose of preventing the wound and the dirt which arises at the time of processing and conveying a to-be-adhered body by using the adhesive layer apply | coated on the protective film side, ie, a to-be-adhered body.

In one example, the polarizing plate used in the liquid crystal display panel is the surface attached to the pressure-sensitive adhesive layer of the surface protection film is protected by the surface protection film, and then removed by peeling in the inspection process. At this time, since the protective film and the adhesive which comprise a surface protection film are comprised by the plastic material, electrical insulation is high and static electricity generate | occur | produces at the time of friction and peeling. At this time, if foreign matter is deposited on the surface by static electricity generated or voltage is applied to the liquid crystal in the state of static electricity remaining, the orientation of the liquid crystal molecules is lost and defects are caused because the panel is defective. In order to prevent such a phenomenon, various antistatic agents are used in the surface protection film.

In recent years, the surface treatment of a polarizing plate is performed in various ways. The surface treatment of the polarizing plate includes an anti-glare layer, a low refractive layer and / or a high refractive layer, an antifouling layer, and the like, each having a different surface roughness and surface energy. In particular, the anti-glare layer has a rougher surface roughness and lower surface energy than the triacetyl cellulose (hereinafter referred to as "TAC") layer, so that a large amount of bubbles are generated in the autoclave process due to the incorporation of fine bubbles when the protective film is attached. The wettability of the pressure-sensitive adhesive for protective film is important because it causes.

Various types of plasticizers or surfactants are used to increase the antistatic property and to improve the wet property during such peeling.

In Japanese Patent Laid-Open No. 6-128539, a polyether polyol compound and an alkali metal salt are used as an antistatic agent in order to prevent the antistatic agent from detaching from the surface of the adherend. . However, if the above technique is also processed under high temperature conditions, the bleeding phenomenon is inevitable and the surface of the adherend is contaminated. In order to improve this, Japanese Patent Laid-Open No. 2006-111856 adds an antistatic agent composed of an ethylene oxide group-containing compound and an alkali metal salt. However, by using a hydrophilic compound called an alkylene oxide, it is absorbed under time or moisture and heat conditions, causing a change in adherend properties due to contamination of the adherend or penetration of moisture. In particular, in the case of the TAC layer used for polarizer protection of the polarizing plate, when the moisture absorbs, the TAC layer expands and causes curl of the polarizing plate due to the difference in the expansion ratio of the upper and lower layers.

In Korean Patent Publication No. 2007-0041238, a hydrophilic complex compound and a hydrophobic complex compound are used in combination to provide antistatic properties to an untreated TAC and an anti-glare layer (AG TAC) and to prevent bleed-out. . However, even if the amount of the hydrophilic complex compound used is added in an amount of about 0.5 parts by weight with respect to 100 parts by weight of the adhesive resin, curling of the polarizing plate cannot be prevented under moisture-resistant heat conditions.

It is known that curl of a polarizing plate which is made of a multilayer is caused by moisture absorption and expansion due to aging of the layer, and is thus caused by deviating between layers. Such curls cause great problems in the dimensional stability of the polarizing plate, and are recognized as important problems in connection with problems such as peeling between layers, deterioration of reliability due to peeling from the glass substrate, light leakage of the polarizing plate, and the like.

In Japanese Patent Laid-Open No. 2005-049597, as a liner (or liner or separator) in which curl generation is suppressed, the difference between the shrinkage rate (X) of the liner and the shrinkage rate (Y) of the laminated polarizer with liner is defined as shown in Equation 1 below. Doing.

-0.1 ≤ shrinkage (X)-shrinkage (Y) ≤ 0

In other words, it is proposed that there is no difference between the shrinkage rate (X) of the liner and the shrinkage rate (Y) of the laminated polarizer with a liner, or that it is negative.In the curl direction, the liner shrinkage is smaller than that of the laminated polarizer with a liner. Or (+) curl, embossed curl) "

)로 나타난다.That is, a polarizing plate; adhesive; And in the protective film in which the liner is sequentially laminated, if the liner shrinkage is less than the shrinkage of the laminated polarizer with a liner, since the shrinkage of the polarizing plate located at the bottom occurs a lot, the pressure-sensitive adhesive is raised upward (+) curl (

Appears.

In addition, Japanese Patent Application Laid-Open No. 2005-326531 discloses a polarizing plate with a protective film in which the moisture content before the pressure-sensitive adhesive layer and separator lamination is 2.85 to 3.8% by weight, and the moisture content of the pressure-sensitive adhesive polarizing plate is 2.0 to 2.7% by weight.

In this case, by setting the evaluation criteria that the (+) curl is 35 cm or less and the (-) curl is 5 cm or less, it is known that the (-) curl is a more important factor in causing the defect of the polarizer than the (+) curl. .

In Japanese Patent Laid-Open No. 2005-338367, a protective film is laminated on one surface of a polarizing plate, and an adhesive layer and a separator are laminated on a rear surface of the polarizing plate, wherein the shear adhesive force (F1) and the adhesive layer between the polarizing plate and the protective film are laminated. And the relationship between the shear adhesion force (F2) between the separators, as shown in Equation 2 below.

0.08 ≤ F2 / F1 ≤ 12.5

That is, it is proposed that (+) curl generate | occur | produces so that the value of the shear adhesive force F2 between an adhesive layer and a separator is large.

As described above, various attempts have been made to solve the problem of the conventional polarizer curl, but there is a limit in fundamentally solving the curl problem of the polarizer.

Accordingly, the present inventors have made efforts to fundamentally solve the curl problem of the polarizing plate, to provide a novel acrylic pressure-sensitive adhesive composition that can solve the problem of static electricity charging or contamination in a balanced manner, and the surface protective film containing the acrylic pressure-sensitive adhesive composition The present invention was completed by almost no influence on the characteristics of the adherend or curling under moisture and heat resistance conditions, excellent contamination resistance to the adherend, excellent reliability of peeling force, and excellent antistatic property during peeling.

An object of the present invention is to provide an acrylic pressure-sensitive adhesive composition that can solve the problem of static electricity charging or pollution.

Another object of the present invention is to contain an hydrophilic compound in the acrylic copolymer in an optimum amount, so that there is little influence on the characteristics of the adherend or curling under moisture and heat conditions, excellent contamination resistance to the adherend, reliable peeling force, when peeling It is to provide an acrylic pressure-sensitive adhesive composition excellent in antistatic properties.

Still another object of the present invention is to provide a surface protective film in which a pressure-sensitive adhesive layer containing the acrylic pressure-sensitive adhesive composition is laminated on at least one surface of a base film.

In order to achieve the above object, the present invention comprises (a) an acrylic copolymer, (b) a hydrophilic compound and (c) a non-hydrophilic compound, the hydrophilic compound is 0.01 to 100 parts by weight of the solid content of the acrylic copolymer, It provides an acrylic pressure-sensitive adhesive composition containing 0.5 parts by weight.

(B) Hydrophilic compounds used in the present invention are -COOH, -COOM (M is a monovalent, divalent or trivalent metal ion or substituted or unsubstituted ammonium ion), -OH, -NH ₂ , -SO ₃ H Selected from the group consisting of a compound or an ether group (-O-), a ketone group (-CO-) and an ester group (-COO-) containing a polar group selected from the group consisting of a amide group and a phosphate ester group It includes the compound containing the polar group to become in a structure.

Preferred examples of the hydrophilic compound include at least one selected from the group consisting of polyether esters, polyvinyl pyrrolidones, vinyl pyrrolidone-vinyl acetate copolymers, polyvinyl ethers, and menyl vinyl ether-maleic anhydride copolymers. It is to use that.

In particular, the polyether ester compound is a compound containing an alkylene oxide group having an alkyl group having 1 to 10 carbon atoms, more preferably the polyether ester compound is selected from the group of polyalkylene oxide compounds having 2 to 4 carbon atoms. It is a copolymer consisting of one or more kinds or two or more kinds.

In the acrylic pressure-sensitive adhesive composition of the present invention, (a) the acrylic copolymer is iii) 90 to 99.9 wt% of (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms and ii) a vinyl monomer and an acrylic monomer having a crosslinkable functional group. It is to use the one prepared by copolymerizing 0.1 to 10% by weight alone or mixed form selected from.

In addition, in the acrylic pressure-sensitive adhesive composition of the present invention, (c) the non-hydrophilic compound is in the form of a metal salt or an organic salt excluding a hydrophilic group, and usually within a range satisfying these conditions, a plasticizer, an antistatic agent, a surfactant, an antioxidant, a foaming agent, It is to use an additive component alone or in combination of two or more selected from compounds used as antifoaming agents, reinforcing agents, colorants, and fillers.

The present invention provides a surface protective film in which a pressure-sensitive adhesive layer containing the acrylic pressure-sensitive adhesive composition is laminated on at least one surface of the base film and the base film.

Furthermore, the surface protective film of the present invention is particularly useful as a surface protective film for a liquid crystal display polarizing plate because the acrylic pressure-sensitive adhesive composition is effective for preventing curl generation of adherends under moisture and heat conditions.

According to the present invention, there is provided an acrylic pressure-sensitive adhesive composition containing the hydrophilic compound in an optimum amount with respect to the acrylic copolymer to control the physical properties, and in particular, there is little influence on the adherend properties or curling under moisture and heat conditions, It is possible to provide an acrylic pressure-sensitive adhesive composition that is excellent in stain resistance, and has excellent reliability peel strength and antistatic property at the time of peeling.

In addition, the present invention is excellent in the physical properties, in particular, using an acrylic pressure-sensitive adhesive composition effective for preventing the occurrence of curl and the effect on the adherend properties in the heat and humidity conditions, the polar protective plate surface protective film that can fundamentally solve the curl problem of the polarizing plate Can be provided.

Hereinafter, the present invention will be described in detail.

The present invention comprises (a) an acrylic copolymer, (b) a hydrophilic compound, and (c) a non-hydrophilic compound, wherein the hydrophilic compound contains 0.01 to 0.5 parts by weight based on 100 parts by weight of solids of the acrylic copolymer. To provide a composition.

Hereinafter, each composition constituting the acrylic pressure-sensitive adhesive composition of the present invention will be described in detail.

(a) Acrylic Copolymer

The (a) acrylic copolymer used in the present invention is not particularly limited as long as it is commonly used as an adhesive in the art, but preferably iii) 90 to 99.9 weight of (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms. % And ii) a copolymer prepared by copolymerizing 0.1 to 10% by weight of a single or mixed form of a vinyl monomer having a crosslinkable functional group and an acrylic monomer.

I) The (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms may be used by copolymerizing with a co-monomer having a high glass transition temperature in order to impart adhesion and cohesion to the acrylic copolymer.

Preferred examples of the (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms include i) alkyl ester having 1 to 12 carbon atoms of acrylic acid (or methacrylic acid), specifically butyl (meth) acrylate and ethyl. (Meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, n-octyl meta In the group consisting of acrylate, n-tetradecyl methacrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate and 2-ethylbutyl (meth) acrylate It can be used individually or in mixture of 2 or more types selected.

The vinyl-based monomer and / or the acrylic-based monomer having the crosslinkable functional group of ii) react with the crosslinking agent to provide a cohesive force or adhesive strength by firm chemical bonding so that cohesive breakage of the pressure-sensitive adhesive does not occur at high temperature or high humidity conditions. .

Preferred examples of the vinyl monomer having a crosslinkable functional group and / or acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth). Monomers containing a hydroxy group such as acrylate, 6-hydroxyhexyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate, or 2-hydroxypropylene glycol (meth) acrylate; Monomers containing a carboxyl group such as (meth) acrylic acid, maleic acid, or fumaric acid; Or a mixture of two or more selected from nitrogen-containing monomers such as acrylamide, N-vinyl pyrrolidone or N-vinyl caprolactam.

The preferred content of the vinyl-based monomer and / or acrylic monomer having a crosslinkable functional group is contained in 0.1 to 10% by weight, if the content is less than 0.1% by weight, there is a problem that cohesive failure is likely to occur at high temperature or high humidity conditions On the other hand, if it exceeds 10% by weight, the compatibility is reduced to reduce the flow characteristics.

(b) hydrophilic compounds

(B) Hydrophilic compound used in the present invention is -COOH, -COOM (M is a monovalent, divalent or trivalent metal ion or substituted or unsubstituted ammonium ion), -OH, -NH ₂ , -SO ₃ H A compound containing a polar group selected from the group consisting of a amide group and a phosphate ester group at the terminal of the structure. In addition, the compound containing a polar group selected from the group consisting of ether group (-O-), ketone group (-CO-) and ester group (-COO-) in the structure, the hydrophilic compound of the present invention is an alkyl group or It means the compound which shows hydrophilicity rather than nonpolar groups, such as an aromatic residue.

The hydrophilic compound is 0.01 to 0.5 parts by weight, preferably 0.01 to 0.3 parts by weight, more preferably 0.05 to 0.3 parts by weight based on 100 parts by weight of the acrylic copolymer. At this time, if the content of the hydrophilic compound is less than 0.01 parts by weight, moisture absorption of the adherend is prevented, but curl generation is prevented, but antistatic property is poor for hydrophilic substrates such as untreated TAC, and wettability on the hydrophilic surface is greatly reduced. On the other hand, if the content of the hydrophilic compound exceeds 0.5 parts by weight, the antistatic property and wettability of the hydrophilic substrate is improved, but moisture absorption is induced to the adherend to which the pressure-sensitive adhesive is attached to induce swelling by moisture, resulting in an unbalanced form of the adherend. It will cause curls. In particular, when used as a pressure-sensitive adhesive for the protective film TAC attached to the protective film is expanded by the absorption of moisture to induce (-) curl in the polarizing plate causes a large failure. Therefore, the hydrophilic compound of the present invention can not be used for antistatic property or wettability, but the amount of the hydrophilic compound should be optimized to a minimum in order to prevent curling.

The hydrophilic compound used in the present invention is at least one selected from the group consisting of polyether esters, polyvinyl pyrrolidones, vinyl pyrrolidone-vinyl acetate copolymers, polyvinyl ethers and menyl vinyl ether-maleic anhydride copolymers. It is to use that.

In particular, the polyether ester compound is the most commonly used among the materials exhibiting antistatic properties, specifically, a compound containing an alkylene oxide group having an alkyl group having 1 to 10 carbon atoms, more preferably having 2 to 4 carbon atoms. At least one selected from the group of polyalkylene oxide compounds is mixed. Specific examples thereof include polyethylene oxide, polypropylene oxide, poly 1,3-butylene oxide, poly 1,4-butylene oxide and the like.

Looking at the specific composition of the compound containing an ethylene oxide group having 2 carbon atoms in the alkylene oxide compound, as the compound containing an ethylene oxide group, if the compound having an ethylene oxide group is not particularly limited, a known ethylene oxide group containing compound may be used as appropriate Can be.

Examples thereof include polyoxyethylene alkyl amines, polyoxyethylene diamines, polyoxyethylene fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl ethers, and the like. Anionic surfactants, such as a warm surfactant, a polyoxyethylene alkyl ether sulfate ester salt, and a polyoxyethylene alkyl phenyl ether phosphate ester salt, a cationic surfactant which has an ethylene oxide group, ethylene glycol, etc. are mentioned. In this case, specific examples of ethylene glycol include polyethylene glycol, polydiethylene glycol, polytriethylene glycol, polyhexethylene glycol, and the like, and the compound may be used alone or in combination of two or more thereof.

Furthermore, it is not limited to the compound containing a C2-C ethylene oxide group among the said alkylene oxide compounds, It is similarly applied to the C2-C or more alkylene oxide compound.

That is, two or more of the alkylene oxide compounds may be selected to form a copolymer. Examples thereof include polypropylene oxide-polyethylene oxide, polypropylene oxide-polyethylene oxide-polypropylene oxide, block copolymers of polyethylene oxide-polypropylene oxide-polyethylene oxide, random copolymers of polyethylene oxide and polypropylene oxide, or star-shaped aerials. A coalescence is mentioned, It can use individually or in mixture of 2 or more types.

(c) Non-hydrophilic  compound

(C) The non-hydrophilic compound used in the present invention means a material used to compensate for the improvement of the antistatic property and the wettability to the adherend as the hydrophilic compound is used for the purpose of preventing curl generation.

In this case, the non-hydrophilic compound in the present invention may be used without particular limitation, so long as it is a compound in the form of a metal salt or organic salt excluding a hydrophilic group, within the range that satisfies these conditions, plasticizers, antistatic agents, surfactants, Compounds used alone or in combination of two or more selected from compounds used as antioxidants, foaming agents, antifoaming agents, reinforcing agents, colorants, and fillers may be used.

In addition, the present invention is a base film; And a pressure-sensitive adhesive layer containing the acrylic pressure-sensitive adhesive composition on at least one surface of the base film.

Furthermore, the present invention has little effect on curling properties or curling under moisture and heat conditions, and excellent antifouling resistance to the adherend, and excellent antistatic property by using an acrylic pressure-sensitive adhesive composition having excellent peeling strength and antistatic properties during peeling, It can provide the surface protection film for polarizing plates which can simultaneously solve the property and stain resistance, and can solve the curl problem of a polarizing plate fundamentally.

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

This embodiment is intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples.

< Example  1>

Step 1: preparing the acrylic copolymer

89.0 wt% of 2-ethylhexyl acrylate (2-EHA), 9.0 wt% of n-butyl acrylate (BA), and 2-hydroxy in a 1 L reactor equipped with a refrigeration system for easy reflux of nitrogen gas After the monomer mixture consisting of 2.0% by weight of ethyl acrylate (2-HEA) was added, 100 parts by weight of an ethyl acetate (EAc) solvent was added to 100 parts by weight of the monomer mixture. Then, after purging nitrogen gas for 1 hour to remove oxygen, it was maintained at 55 ℃. To the mixture was added 0.05 parts by weight of azobisisobutyronitrile (AIBN) diluted to 50% concentration in ethyl acetate as a reaction initiator, and reacted for 8 hours to prepare an acrylic copolymer.

2. Compounding and Coating Process

To 100 parts by weight of the acrylic copolymer prepared above, 3.0 parts by weight of prepolymer (HDI) of hexamethylene diisocyanate, 0.1 parts by weight of polyethylene oxide (molecular weight 1000) and 0.5 parts by weight of lithium perchlorate were added as a crosslinking agent, and diluted to an appropriate concentration. After uniformly mixing, the coating was coated on one surface of a biaxially stretched polyethylene terephthalate film having a thickness of 38 μm, and dried to prepare a uniform adhesive layer having a thickness of 20 μm.

3. Plywood Process

The release film was laminated on the adhesive layer coated on one side of the polyethylene terephthalate film, and stored for 3 days at a temperature of 50 ° C. for sufficient aging.

The surface protection film prepared as described above was cut to an appropriate size and attached to the triacetyl cellulose surface (normal TAC film, Japan Fuji Film Co.) and anti-glare layer surface (AG TAC, Japan DNP Co., Ltd., surface roughness 0.3) of the polarizing plate, respectively. Performance evaluation was performed.

< Example  2 to 6>

It was carried out in the same manner as in Example 1, except that it was carried out in the component and its composition ratio as shown in Table 1 below. At this time, the unit of each numerical value of Table 1 is a weight part.

division Example Comparative example One 2 3 4 5 6 One 2 3 4 5 Acrylic Copolymer 100 100 100 100 100 100 100 100 100 100 100 Hydrophilic
compound PEO 0.1 - - - - - 0.0 2.0 - - - PPO - 0.1 - - - - - - 2.0 - - PEL-20A - - 0.05 0.1 0.3 - - - - 3.0 - PEL-100A - - - 0.1 - - - - 3.0 Non-hydrophilic
compound LiClO ₄ 0.5 - - - - - 0.5 - - - - LiN (SO ₂ CF ₃ ) ₂ - 0.5 - - - - - - - 0.5 - DOP 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 PEO: Polyethylene oxide (molecular weight 1000)
PPO: Polypropylene Oxide (Molecular Weight 1200)
PEL-20A: PEO-PPO copolymer (PEO> PPO) / Metal salt content (10%)
PEL-100A: PEO-PPO copolymer (PEO <PPO) / Metal salt content (10%)
LiClO ₄ : Lithium Perchloride
LiN (SO ₂ CF ₃ ) ₂ : Lithium bistrifluoromethanesulfonimide
DOP: Di-2-ethylhexyl phthalate

< Experimental Example  1>

The protective film prepared in Examples 1 to 4 and Comparative Examples 1 to 5 was measured in the same amount as the amount of curl, peel strength, wettability and durability, and the results are shown in Table 2 .

One. Curl  Volume measurement

After attaching the protective film, the pressure-sensitive adhesive, and the separators prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were cut into 15 inch size so that the axial angle of the polarizing plate is 45 °, to make an initial sample, 60 ℃ × 90% RH After storage for 100 hours in the environment, the height was measured by separating the (+) curl and (-) curl.

2. 180 ° Peel strength  Measure

The protective films prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were applied to JIS Z 0237 on the triacetyl cellulose (TAC, manufactured by Fujifilm, Japan) surface and the antiglare layer (AG, manufactured by DNP, Japan) of the polarizing plate. After attaching with a roller of 2 kg, it measured using the tensile tester at 180 degree angle and the peeling speed of 0.3 m / min and 30 m / min.

3. Wetting

The protective films prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were attached to the AG surface of the polarizing plate (strip type of 25 mm x 50 mm) with a roller of 2 kg according to JIS Z 0237, and then After peeling off a protective film, it measured by the time when an adhesive surface adheres again. In addition, the protective film was attached to the AG surface of the polarizing plate (250 mm × 250 mm) with a roller of 2 kg, and then the presence or absence of air bubbles after the autoclave process at 75 ° C. and 5 kg / cm 2 for 90 minutes was determined.

4. Peeling voltage  Measure

The protective films prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were attached to the untreated TAC side and AG side of the polarizing plate with a roller of 2 kg based on JIS Z 0237, and cut into 15 inch sizes, and cut to 30 m / s. The constant voltage generated using a constant voltage meter (Statiron-DZ3) was measured at a height of 30 mm from the surface of the polarizing plate while peeling at the rate of minutes. At this time, in Table 2, no treatment is a normal TAC, and AG denotes an anti-glare treatment (AG TAC).)

division Curl quantity
[Cm] Peeling band voltage [KV] Wettability Peel Strength [gf / 25㎜] No treatment AG time
[second] bubble
The presence or absence 0.3m / min 30m / min No treatment AG No treatment AG Example 1 -2.4 0.5 -0.5 10 × 8 7 104 100 Example 2 -2.2 0.6 -0.5 9 × 8 7 110 102 Example 3 +0.2 0.7 -0.5 11 × 8 8 112 108 Example 4 -1.5 0.3 -0.5 10 × 7 8 100 102 Example 5 -1.8 0.2 -0.2 9 × 6 7 96 98 Example 6 -1.2 0.3 -0.5 10 × 8 9 102 105 Comparative Example 1 +1.1 1.3 -0.8 9 × 13 11 141 135 Comparative Example 2 -9.4 0.2 -1.2 13 ○ 6 8 90 95 Comparative Example 3 -8.2 0.3 -1.2 13 ○ 6 8 95 95 Comparative Example 4 -9.5 0.2 -0.1 14 × 7 6 92 90 Comparative Example 5 -8.7 0.1 -0.8 13 × 6 7 95 97

As shown in Table 2, according to the present invention, the film using the acrylic pressure-sensitive adhesive composition of Examples 1 to 6, compared to the film prepared in Comparative Examples 1 to 5, the effect or curl on the adherend characteristics under moisture and heat conditions It hardly occurred and was excellent in stain resistance. In addition, it was confirmed that the durability, antistatic properties and excellent peeling force.

As described above, the present invention provides an acrylic pressure-sensitive adhesive composition containing 0.01 to 0.5 parts by weight of the hydrophilic compound with respect to 100 parts by weight of the acrylic copolymer, the present invention by limiting the content of the hydrophilic compound to control the physical properties The present invention provides an acrylic pressure-sensitive adhesive composition having little effect on curling properties or curling under moisture and heat resistance conditions, excellent stain resistance to adherends, and excellent peeling strength and antistatic properties during peeling.

Accordingly, the present invention provides a surface protection film comprising the pressure-sensitive adhesive layer containing the acrylic pressure-sensitive adhesive composition of the present invention, in particular, the surface protection film of the present invention simultaneously solves the antistatic property and the stain resistance, and in particular, fundamentally solves the curl problem of the polarizing plate. It is useful as a surface protection film for polarizing plates that can be solved.

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

Claims (10)

(a) an acrylic copolymer, (b) hydrophilic compounds and (c) an acrylic pressure-sensitive adhesive composition for a polarizing plate surface protective film comprising a non-hydrophilic compound, wherein the hydrophilic compound is contained in an amount of 0.01 to 0.3 parts by weight based on 100 parts by weight of the solid content of the acrylic copolymer, thereby suppressing the occurrence of curl under moisture and heat conditions. . The method according to claim 1, wherein the hydrophilic compound is -COOH, -COOM (M is a monovalent, divalent or trivalent metal ion or substituted or unsubstituted ammonium ion), -OH, -NH ₂ , -SO ₃ H, The acrylic pressure-sensitive adhesive composition for polarizing plate surface protective film, characterized in that the compound containing a polar group selected from the group consisting of an amide group and a phosphate ester group at the end of the structure. The method of claim 1, wherein the hydrophilic compound is a compound containing in the structure a polar group selected from the group consisting of ether group (-O-), ketone group (-CO-) and ester group (-COO-) Acrylic pressure-sensitive adhesive composition for the polarizing plate surface protective film. The method according to claim 1, wherein the hydrophilic compound is selected from the group consisting of poly ether esters, poly vinyl pyrrolidones, vinyl pyrrolidone-vinyl acetate copolymers, polyvinyl ethers and menyl vinyl ether-maleic anhydride copolymers. Acrylic type adhesive composition for said polarizing plate surface protection film characterized by the above-mentioned. The acrylic pressure-sensitive adhesive composition for polarizing plate surface protective film according to claim 4, wherein the polyether ester compound is a compound containing an alkylene oxide group having an alkyl group having 1 to 10 carbon atoms. The acrylic pressure-sensitive adhesive for polarizing plate surface protective film according to claim 5, wherein the polyether ester compound is a copolymer composed of one or more selected from the group of polyalkylene oxide compounds having 2 to 4 carbon atoms. Composition. delete delete Base film; A pressure-sensitive adhesive layer containing the acrylic pressure-sensitive adhesive composition of claim 1 on at least one surface of the base film; Laminated surface protective film for polarization is suppressed curl generation in heat and humidity conditions. delete