KR20160146586A - Pressure sensitive adhesive composition - Google Patents

Abstract

The present invention relates to an adhesive composition, a protection film, an optical element, and a display device. An adhesive sheet formed by using the adhesive composition of the present invention exhibits a proper level of surface resistance and excellent peeling and charge characteristics. Also, when being detached from an object after being attached to the object for a long period of time, the adhesive sheet does not leave any contamination on the object. Thus, the adhesive sheet formed by using the adhesive composition of the present invention can be applied to various uses. For example, the adhesive sheet can be used as a protection film on an optical member such as a polarizing plate. The adhesive composition includes an acrylic resin having a molecular weight distribution of 5 or less.

Description

[0001] PRESSURE SENSITIVE ADHESIVE COMPOSITION [0002]

The present application is directed to a pressure sensitive adhesive composition.

A protective film may be used to prevent dust, dirt, or the like from adhering to the optical element such as a polarizing plate, other plastic products, household appliances, automobiles, or the like. The protective film is required to have an appropriate peeling force and antistatic property.

For example, when a protective film is peeled at a high speed for use of a product or for assembling another product, it is required that the peel force (hereinafter, referred to as "high peel force") be relatively low. On the other hand, the peeling force (hereinafter referred to as " low-speed peeling force ") at the time of peeling at a slow rate may be relatively high to exhibit an appropriate protective function.

In addition, foreign matter such as dust may be sucked due to static electricity generated mainly at the time of peeling off the protective film, and in the case of electronic products, electrostatic destruction or malfunction of the device may be caused. Particularly, in recent years, due to the spread of computers and the multifunctionality of liquid crystal TVs and mobile phones, components are integrated, and problems caused by static electricity are becoming more and more evident.

Accordingly, efforts have been made to impart an antistatic function to the pressure-sensitive adhesive contained in the protective film.

For example, in Patent Document 1, there is an attempt to suppress the generation of static electricity by blending an ethylene oxide-modified dioctyl phthalate plasticizer with a pressure-sensitive adhesive. In Patent Document 2, an organic salt is added to a pressure-sensitive adhesive, and in Patent Document 3, a metal salt and a chelating agent are mixed in a pressure-sensitive adhesive. However, according to the above methods, it is difficult to prevent the occurrence of contamination of the pressure sensitive adhesive component by transfer to the protected product or the static electricity generated at the initial stage.

Japanese Patent Application Laid-Open No. 1993-140519 Korean Patent Publication No. 2004-0030919 Korean Patent Publication No. 2006-0128659

The present application provides a pressure-sensitive adhesive composition. The pressure-sensitive adhesive sheet formed using the pressure-sensitive adhesive composition of the present application exhibits appropriate high-speed and low-speed peel force and can maintain a good balance between them. The pressure-sensitive adhesive sheet formed by using the pressure-sensitive adhesive composition of the present application exhibits an appropriate level of surface resistance and excellent peeling electrification characteristics, and does not leave any contamination on the adherend even after being peeled off after adhering to the adherend for a long time. The pressure-sensitive adhesive sheet using the pressure-sensitive adhesive composition of the present application can be applied to various applications, and can be used as a protective film for an optical member such as a polarizing plate.

Exemplary pressure sensitive adhesive compositions may comprise acrylic adhesive resins. The term acrylic adhesive resin in the present application means a resin having properties capable of forming a pressure-sensitive adhesive and containing an acrylic monomer as a main component. The term acrylic monomer may mean a derivative of acrylic acid or methacrylic acid such as acrylic acid, methacrylic acid or (meth) acrylic acid ester. The inclusion of the main component in the present application means that the proportion of the component is at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90% 95% or more. The upper limit of the ratio may be 100%.

The acrylic pressure-sensitive adhesive resin may have a molecular weight distribution of 5 or less. The term molecular weight distribution can mean the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn). In the present application, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values converted to standard polystyrene (PS) measured by GPC (Gel Permeation Chromatography). In another example, the molecular weight distribution may be less than 4.5, less than 4, less than 3.5, less than 3, less than 2.5 or less than 2. The molecular weight distribution may be one or more.

The adhesive resin may be a so-called Living Radical Polymerized Polymer. The term living radical polymer may be a resin produced by the LRP (Living Radical Polymerization) method. The resin synthesized by the LRP method shows a narrow molecular weight distribution (PDI, Mw / Mn). In addition, the adhesive resin has a low proportion of low molecular weight components. When such a pressure-sensitive adhesive resin is applied, for example, a pressure-sensitive adhesive capable of minimizing contamination on the surface of an adherend after peeling can be provided.

The living radical polymer may be a random copolymer or a block copolymer.

Accordingly, one aspect of the present application relates to a pressure-sensitive adhesive composition comprising a pressure-sensitive adhesive resin produced by a living radical polymerization (LRP) method.

In the present application, the acrylic adhesive resin may have a molecular weight within the range of 50,000 to 3,000,000. In other examples, the molecular weight may be less than 2.5 million, less than 2 million, less than 1.5 million, less than 1,000,000, less than 900,000, less than 800,000 or less than 700,000. The molecular weight may be a weight average molecular weight (Mw).

The adhesive resin preferably has a proportion of a resin component having a molecular weight (weight average molecular weight or number average molecular weight) of 5,000 or less of 5 wt% or less, 4.5 wt% or less, 4 wt% or less, 3.5 wt% or less, 3 wt% Or less, 1.5 wt% or less, or 1 wt% or less. The lower the proportion of the resin component, the lower the staining property of the pressure-sensitive adhesive can be obtained, and the lower limit is not particularly limited. For example, the ratio may be greater than 0 wt% or greater than 0 wt%. In addition, the molecular weight of the resin component may be about 100 or more in another example.

As the adhesive resin, various types of adhesive resins can be used without particular limitation, which indicates any one of the above-mentioned characteristics.

In one example, the pressure-sensitive adhesive resin may include any one or two or more monomers as the monomer components, including a monomer containing an alkylene oxide chain, a nitrogen-containing reactive compound, and a hydroxyl group-containing monomer. As used herein, the term monomers means all kinds of compounds capable of forming an adhesive resin through polymerization. The inclusion of a monomer as a monomer component in the pressure-sensitive adhesive resin may mean that the monomer is polymerized to include side chains or main chains of the pressure-sensitive adhesive resin. Also, unless otherwise specified in this specification, the inclusion, incorporation, or incorporation of a monomer by a pressure-sensitive adhesive resin may mean that the monomer contains, contains, or has the above-mentioned monomer as a polymerization unit.

As the monomer having an alkylene oxide chain, for example, a compound represented by the following general formula (1) can be exemplified.

[Chemical Formula 1]

Q is hydrogen or an alkyl group, U is an alkylene group, Z is hydrogen, an alkyl group or an aryl group, and m is an arbitrary number,

When two or more [-U-O-] units are present in the formula (1), the number of carbon atoms of the U in the unit may be the same or different.

In the formula (1), m is a number within the range of 0 to 20. Within this range, it is possible to maintain the polymerization efficiency and the crystallinity of the adhesive resin in an appropriate range during the production of the adhesive resin, and to impart appropriate conductivity to the adhesive. In particular, the effect of preventing contamination of the adherend within the above range can be maximized.

As used herein, the term alkyl group may mean an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms, unless otherwise specified. The alkyl group may be straight-chain, branched or cyclic. The alkyl group may be substituted by one or more substituents, or may be unsubstituted.

As used herein, unless otherwise specified, the term "alkylene group" or "alkylidene group" means an alkylene group or an alkylidene group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, have. The alkylene group or alkylidene group may be linear, branched or cyclic. The alkylene or alkylidene group may be optionally substituted by one or more substituents.

In another embodiment, Q in formula (1) may be an alkyl group, for example, an alkyl group having 1 to 8 carbon atoms or 1 to 4 carbon atoms. When Q is an alkyl group, for example, it may be advantageous that the protective film is easily removed without residue or unevenness on the adherend when the pressure-sensitive adhesive composition is applied to a protective film or the like.

As used herein, the term aryl group, unless otherwise specified, includes a benzene ring, or two or more benzene rings may be connected, or two or more benzene rings may share one or more carbon atoms, May refer to a monovalent residue derived from a compound or a derivative thereof having a structure represented by the following formula: The aryl group may be, for example, an aryl group having 6 to 25 carbon atoms, 6 to 22 carbon atoms, 6 to 16 carbon atoms, or 6 to 13 carbon atoms. Examples of the aryl group include a phenyl group, a phenylethyl group, a phenylpropyl group, a benzyl group, a tolyl group, a xylyl group and a naphthyl group.

Examples of the substituent which may be substituted in the specific functional group, for example, the alkyl group, the alkylidene group or the alkylene group in the present specification include an alkyl group, an alkoxy group, an alkenyl group, an epoxy group, a cyano group, a carboxyl group, An acryloyloxy group, a methacryloyloxy group or an aryl group, but the present invention is not limited thereto.

As the compound of the formula (1), an alkoxyalkoxyalkyl (meth) acrylate and the like can be mentioned. Examples of the alkoxy include alkoxy having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms and 1 to 4 carbon atoms, and specifically, a methoxy group or an ethoxy group can be exemplified .

The kind of the nitrogen-containing reactive compound that can be contained in the adhesive resin is not particularly limited. As used herein, the term nitrogen-containing reactive compound may mean a compound containing at least one nitrogen atom and having a reactivity capable of being polymerized with other monomers forming a pressure-sensitive adhesive resin. As the above-mentioned compounds, for example, amide group-containing monomers, amino group-containing monomers, imide group-containing monomers or cyano group-containing monomers can be used. Examples of the amide group-containing monomer include amides such as (meth) acrylamide or N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N- (Meth) acrylamide, N, N'-methylenebis (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, , N, N-dimethylaminopropyl methacrylamide, N-vinylpyrrolidone, N-vinylcaprolactam or (meth) acryloylmorpholine. Examples of the amino group-containing monomer include aminoethyl (meth) Acrylate, N, N-dimethylaminoethyl (meth) acrylate or N, N-dimethylaminopropyl (meth) acrylate. Examples of the imide group-containing monomer include N-isopropyl maleimide, N - cyclohexylmaleimide or itaconimide etc. It can be exemplified, and a cyano group-containing monomer include, but as acrylonitrile or methacrylonitrile, etc. The nitrile can be exemplified, without being limited thereto. In order to maximize the effect of securing adequate physical properties, for example, conductivity, and excellent peeling properties, for example, balance of low speed and high speed peeling force and preventing contamination of the adherend, Dialkyl (meth) acrylamide can be used as the nitrogen-containing reactive compound. In this case, the N, N-dialkyl (meth) acrylamide may include an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms.

The adhesive resin may further comprise a hydroxyl group-containing monomer. The monomer may provide a hydroxy group to the adhesive resin.

As the hydroxy group-containing monomer, for example, a monomer represented by the following formula (2) can be mentioned.

(2)

In formula (2), Q is hydrogen or an alkyl group, A and B are each independently an alkylene group, and n is an arbitrary number, for example, a number of 0 to 10.

When two or more [-O-B-] units are present in the general formula (2), the number of carbon atoms of B in the unit may be the same or different

In formula (2), A and B may be, for example, each independently an alkylene group which is linear.

Examples of the compound of formula (2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 2-hydroxyethyleneglycol (meth) acrylate or 2-hydroxypropyleneglycol (meth) acrylate, but are not limited thereto.

In one example, as the hydroxy group-containing monomer, two types of monomers having different carbon numbers in the side chain may be used.

For example, the adhesive resin may be represented by the formula (2), and the first monomer having the number of carbon atoms of the alkylene groups present in A and B in the formula (2) is present in the range of 1 to 3, 4 to 16, 4 to 12, 4 to 8, or 4 to 6 carbon atoms of the alkylene group to which the alkylene group is attached.

When calculating the number of carbons in order to distinguish the first and second monomers, only the number of carbon atoms of the alkylene group formed in a straight chain form is considered. For example, when the substituents containing carbon are substituted for A and B The carbon number of the substituent is not taken into consideration. As described above, the pressure-sensitive adhesive excellent in the peeling force characteristic, that is, the balance between the high-speed and low-speed peeling force, can be provided through the polymerization unit of the two kinds of hydroxyl group monomers. In addition, it is possible to provide a pressure-sensitive adhesive composition which can reduce contamination to an adherend through proper control of the ratio of the monomer.

The ratio of the weight of the first and second monomers in the pressure-sensitive adhesive resin can be adjusted in order to secure the balance of the peeling properties, that is, the excellent low-speed and high-speed peeling force, while securing various properties such as adhesion performance in an appropriate range. For example, the ratio (A / B) of the weight (A) of the first monomer to the weight (B) of the second monomer in the adhesive resin may be 1 or more or more than 1. In another example, the ratio may be greater than or equal to about 1.1 or greater than or equal to about 1.2. In another example, the ratio may be about 25 or less, about 20 or less, about 15 or less, about 10 or less, about 8 or less, or about 5 or less. It is possible to provide a pressure-sensitive adhesive which exhibits an appropriate antistatic property within such a ratio and exhibits a balance of appropriate high-speed and low-speed peeling force without leaving a contaminant at the time of peeling.

The adhesive resin may include any one or two or more of the above-mentioned monomers. In one example, the adhesive resin comprises 0.1 to 5 parts by weight of the monomer of Formula 1, 1 to 30 parts by weight of the nitrogen-containing reactive compound, 0.1 to 15 parts by weight of the first monomer, And 0.1 to 5 parts by weight of the second monomer as a monomer component. Unless specifically stated otherwise in this specification, the unit weight portion may mean the ratio of the weight between each component. For example, the adhesive resin may be prepared by mixing 0.1 to 5 parts by weight of the monomer of the formula (1), 1 to 30 parts by weight of the nitrogen-containing reactive compound, 0.1 to 15 parts by weight of the first monomer and 0.1 to 5 parts by weight of the second monomer, The ratio of the weight (A) of the monomer of formula (1), the weight of the nitrogen-containing reactive compound (B), the weight of the first monomer (C) and the weight of the second monomer (D) May mean that the pressure-sensitive adhesive resin is formed from a mixture of monomers each containing the respective monomers so that the pressure-sensitive adhesive resin (D) is 0.1 to 5: 1 to 30: 0.1 to 15: 0.1 to 5. In another example, the monomer of Formula 1 may be included in about 1 to 5 parts by weight, about 2 to 5 parts by weight, or about 3 to 5 parts by weight. The nitrogen-containing reactive monomer may be included in an amount of about 1 to 25 parts by weight, about 1 to 20 parts by weight, about 1 to 15 parts by weight, about 1 to 10 parts by weight, or about 1 to 7 parts by weight. In addition, the first monomer may be included in about 1 to 10 parts by weight in another example, and the second monomer may be included in about 1 to 5 parts by weight in another example. It is possible to provide a pressure-sensitive adhesive composition which exhibits an appropriate high-speed and low-speed peeling force within a range of the above-mentioned monomers and maintains a good balance between them. Further, by using the pressure-sensitive adhesive resin, a pressure-sensitive adhesive composition which exhibits an appropriate level of surface resistance and excellent peeling electrification characteristics and which does not leave a stain on the adherend even after being peeled off after adhering to an adherend for a long time can be provided. If necessary, the weight ratio (E) of the monomers of formula (1) and the weight ratio (N) of the nitrogen-containing reactive compound in the adhesive resin can be further controlled. For example, From about 0.1 to about 10, from about 0.1 to about 9, from about 0.1 to about 8, from about 0.1 to about 7, from about 0.1 to about 6, from about 0.1 to about 5, from about 0.1 to about 4, from about 0.1 to about 3, from about 0.5 to about 3, ≪ / RTI >

The adhesive resin may further comprise a polymerization unit of a (meth) acrylic acid ester monomer, for example, an alkyl (meth) acrylate.

As the alkyl (meth) acrylate, for example, an alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms may be used in consideration of the cohesive force of the pressure-sensitive adhesive, the glass transition temperature, or the tackiness. Examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, sec-butyl (Meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate and tetradecyl (meth) acrylate. Of these, ≪ / RTI >

The adhesive resin may contain from 65 to 99 parts by weight of the (meth) acrylic acid ester monomer or from 70 to 90 parts by weight of the polymerization unit. The weight ratio may be changed, for example, in consideration of the specific kind of each monomer, etc., if necessary.

The pressure-sensitive adhesive resin may contain, if necessary, a known monomer used for producing a pressure-sensitive adhesive of a pressure-sensitive adhesive, such as (meth) acrylic acid, 2- (meth) acryloyloxyacetic acid, 3- Carboxyl group-containing monomers such as propyl acid, 4- (meth) acryloyloxybutyl acid, acrylic acid doublet, itaconic acid, maleic acid and maleic anhydride; A monomer having an isocyanate group, a monomer having a glycidyl group such as glycidyl (meth) acrylate, or a monomer having a nitrogen atom such as (meth) acrylamide, N-vinylpyrrolidone or N-vinylcaprolactam, And may further include a radically polymerizable monomer such as a monomer or styrene. These monomers may be polymerized and contained in the adhesive resin, and may be included in the adhesive resin in a proportion of, for example, about 20 parts by weight or less.

The pressure-sensitive adhesive resin can be prepared by selecting a necessary monomer among the monomers described above, and applying a mixture of monomers in which the selected monomer is blended in a desired ratio to the Living Radical Polymerization (LRP) method.

The pressure-sensitive adhesive composition may include a light stabilizer, for example, a light stabilizer such as a hindered amine compound. Such a photostabilizer does not aggregate even when the pressure-sensitive adhesive is left under high temperature conditions, for example, and does not cause the phenomenon that the concentration of the antistatic agent described later increases in the agglomerated clusters, and the amount of the alkylene oxide It is possible to prevent the problem that the ether bonding site of the chain is decomposed by heat to generate radicals or that the hydroxyl group containing monomer causes a condensation reaction and the storage stability of the pressure sensitive adhesive composition can be greatly improved.

The pressure-sensitive adhesive composition may further comprise a crosslinking agent, which may react with the crosslinking point of the pressure-sensitive adhesive resin to realize a crosslinked structure.

As the crosslinking agent, for example, an aliphatic isocyanate crosslinking agent can be used. When such a cross-linking agent has a cross-linking structure with the above-mentioned pressure-sensitive adhesive resin, that is, a pressure-sensitive adhesive resin containing two or more kinds of hydroxy group-containing monomers, a pressure-sensitive adhesive having antistatic properties necessary together with appropriate low- and high- For example, as the crosslinking agent, a crosslinking agent comprising an aliphatic cyclic isocyanate compound and / or an aliphatic acyclic isocyanate compound can be used. The term aliphatic cyclic isocyanate compound as used herein means an isocyanate compound containing a cyclic structure and having a cyclic structure in which the structure does not correspond to an aromatic ring. The aliphatic acyclic isocyanate compound may be, for example, an aliphatic linear or branched May mean a branched isocyanate compound. Examples of the aliphatic cyclic isocyanate compound include isocyanate compounds such as isophorone diisocyanate or methylene dicyclohexyl diisocyanate or cyclohexane diisocyanate, A derivative such as a dimer or a trimer or a reaction product of any of the above with a polyol (ex. Trimethylol propane) can be exemplified. As the aliphatic acyclic isocyanate compound, there may be mentioned a compound having a carbon number of 1, such as hexamethylene diisocyanate An alkylene diisocyanate compound having from 1 to 20 carbon atoms, from 1 to 12 carbon atoms, or from 1 to 8 carbon atoms, a derivative thereof such as a dimer or a trimer thereof, or any one of the above and a polyol (e.g., trimethylol Propane) And the like, but the present invention is not limited thereto.

When the aliphatic cyclic isocyanate compound and the aliphatic acyclic isocyanate compound are used together, the ratio is not particularly limited and may be appropriately selected as needed. Generally, from 1 part by weight to 500 parts by weight or from 20 parts by weight to 300 parts by weight of an aliphatic acyclic isocyanate compound may be included in the crosslinking agent, relative to 100 parts by weight of the aliphatic cyclic isocyanate compound. As such a crosslinking agent, that is, a crosslinking agent containing an aliphatic cyclic isocyanate compound and an aliphatic acyclic isocyanate compound may be used, and examples thereof include MHG-80B and Duranate P manufactured by Asahi, or NZ-1 manufactured by BAYER .

As the crosslinking agent, ethylene glycol diglycidyl ether, triglycidyl ether, trimethylol propane triglycidyl ether, N, N, N ', N'-tetraglycidyl ethylenediamine or glycerin Epoxy cross-linking agents such as diglycidyl ether and the like; Bis (1-aziridine carboxamide), N, N'-diphenylmethane-4,4'-bis (1-aziridine carboxamide), triethylene melamine Iron, zinc, tin, titanium, antimony, magnesium, and / or vanadium, such as bis (isoproparyl) -1- (2-methyl aziridine), or tri-1-aziridinyl phosphine oxide, Can be used together with a known crosslinking agent such as a metal chelate crosslinking agent, which is a compound coordinated to acetyl acetone, acetyl acetate or the like.

The pressure-sensitive adhesive composition may include 0.01 to 10 parts by weight or 0.01 to 5 parts by weight of a crosslinking agent based on 100 parts by weight of the pressure-sensitive adhesive resin. In such a range, an appropriate crosslinking structure is realized, and the low speed and high speed peeling force of the pressure sensitive adhesive can be adjusted to a desired range.

The pressure-sensitive adhesive composition may further comprise an antistatic agent. As the antistatic agent, for example, an ionic compound may be used.

As the ionic compound, for example, a metal salt may be used. The metal salt may include, for example, an alkali metal cation or an alkaline earth metal cation. Cations, the lithium ions (Li ^+), sodium ion (Na ^+), potassium ion (K ^+), rubidium ions (Rb ^+), cesium ion (Cs ^+), beryllium ion (Be ^{2 +),} magnesium ion ( Mg ^{2 +),} calcium ions (Ca ^{2 +),} strontium ion (Sr ^{2 +)} and barium ion (Ba ^{2 +)} there is iljong or two kinds or more of the like can be illustrated, for example, a lithium ion, a sodium ion, Potassium ion, magnesium ion, calcium ion and barium ion, or ion stability and mobility.

As the anion contained in the ionic compound is _{^{PF 6 -, AsF -, NO}} 2 -, fluoride (F ^-), chloride (Cl ^-), bromide (Br ^-), iodide (I ^-), perchlorate (ClO ₄ ^-), hydroxide (OH ^-), carbonate (CO ₃ ^{2 -),} nitrate (NO ₃ ^-), trifluoromethane sulfonate (CF ₃ SO ₃ ^-), sulfonate (SO ₄ ^-), hexafluorophosphate (PF ₆ ^-), methyl benzene sulfonate _{(CH 3 (C 6 H 4} ) SO 3 -), p- toluenesulfonate _{(CH 3 C 6 H 4 SO} 3 -), tetraborate (B ₄ O ₇ ^2-), carboxymethyl sulfonate _{(COOH (C 6 H 4)} SO 3 -), sulfonate as a triple (CF ₃ SO ₂ ^-), benzo carbonate ^{_{(C 6 H 5 COO -)}} , acetate ( a), a triple acetate _{^{- CH 3 COO (CF 3 COO}} -), tetrafluoroborate (BF ₄ ^-), tetra-benzyl borate _{(B (C 6 H 5)} 4 -) or tris pentafluoroethyl trifluoromethyl Phosphate (P (C ₂ F ₅ ) ₃ F ₃ ^- ), and the like.

In another example, the anion may be an anion or bifluorosulfonylimide represented by the following formula (5), or the like.

[Chemical Formula 5]

[X (YO _m R _f ) _n ] ^-

X is a nitrogen atom or a carbon atom, Y is a carbon atom or a sulfur atom, R _f is a perfluoroalkyl group, m is 1 or 2, and n is 2 or 3.

In formula (5), when Y is carbon, m is 1, and when Y is sulfur, m is 2, n is 2 when X is nitrogen, and n is 3 when X is carbon.

The anion or bis (fluorosulfonyl) imide of formula (5) exhibits high electronegativity due to the perfluoroalkyl group (R _f ) or the fluorine group and also forms a weak bond with the cation, including a unique resonance structure And at the same time has hydrophobicity. Therefore, the ionic compound exhibits excellent compatibility with other components of a composition such as a pressure-sensitive adhesive resin, and can give a high antistatic property even in a small amount.

R _f in Formula 5 may be a perfluoroalkyl group having 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, wherein the perfluoroalkyl group may be a straight chain, And may have a cyclic structure. The anion of formula (5) may be a sulfonylimide-based, sulfonylimide-based, carbonylimide-based or carbonylimide-based anion, and specifically includes tris trifluoromethanesulfonylmethide, bistrifluoromethanesulfonyl A perfluorobutanesulfonylimide, bispentafluoroethanesulfonylimide, tris trifluoromethanecarbonylmide, bis perfluorobutanecarbonylimide or bispentafluoroethanecarbonyl, bispentafluoroethanesulfonylimide, bis Imide, etc., or a mixture of two or more species.

Examples of the ionic compound include N, N-dimethyl N-propylammonium, N, N, N-trimethyl-N-propylammonium, N-methyl- N, N, N-trihexylammonium, N-methyl-N, N, N-trihexylammonium, N-ethyl- Quaternary ammonium such as N, N, N-trioctylammonium or N-ethyl-N, N, N-trioctylammonium, phosphonium, pyridinium, imidazolium, An organic salt containing pyrolidinium or piperidinium together with the anion component may be used and, if necessary, the metal salt and the organic salt may be used in combination.

The content of the ionic compound in the pressure-sensitive adhesive composition is not particularly limited and may be, for example, 0.01 to 5 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive resin. The ratio of the ionic compound can be changed in consideration of the desired antistatic property and compatibility between the components.

The pressure-sensitive adhesive composition may further include a silane coupling agent. Examples of the coupling agent include gamma-glycidoxypropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-glycidoxypropyltriethoxysilane , 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-methacryloxypropyltriethoxysilane, gamma-aminopropyltri But are not limited to, methoxy silane, gamma-aminopropyl triethoxy silane, 3-isocyanatopropyl triethoxy silane, gamma-acetoacetate propyl trimethoxysilane, gamma-acetoacetate propyl triethoxy silane, Trimethoxysilane, beta-cyanoacetyltriethoxysilane, acetoxyacetotrimethoxysilane, and mixtures of one or more of the above can be used. . For example, as the silane coupling agent, it may be appropriate to use a silane coupling agent having an acetoacetate group or a beta-cyanoacetyl group. The silane coupling agent may be included in the adhesive composition in an amount of 0.01 to 5 parts by weight, or 0.01 to 1 part by weight based on 100 parts by weight of the adhesive resin. An appropriate adhesive force increasing effect and endurance reliability can be ensured within the above range.

The pressure-sensitive adhesive composition may further include a tackifier in view of control of the tack performance. Examples of the tackifier include a hydrocarbon resin or a hydrogenated product thereof, a rosin resin or a hydrogenated product thereof, a rosin ester resin or a hydrogenated product thereof, a terpene resin or a hydrogenated product thereof, a terpene phenol resin or a hydrogenated product thereof, Ester resins and the like, or mixtures of two or more thereof. The tackifier may be included in the composition in an amount of 1 part by weight to 100 parts by weight based on 100 parts by weight of the co-adhesive resin. It is possible to secure a suitable addition effect and a commercial and cohesive force improving effect in the above content range.

The pressure-sensitive adhesive composition may also contain a coordinating compound capable of forming a coordination bond with the antistatic agent, a photoinitiator, a multifunctional acrylate, an epoxy resin, a crosslinking agent, a UV stabilizer, an antioxidant, A colorant, a reinforcing agent, a filler, a defoaming agent, a surfactant, and a plasticizer.

The pressure-sensitive adhesive composition preferably has a low peeling strength of about 1 gf / 25 mm to 40 gf / 25 mm, 1 gf / 25 mm to 35 gf / 25 mm, and a low peel strength for an adherend having a surface energy of 30 mN / 25 g / 25 mm to 30 gf / 25 mm, 1 gf / 25 mm to 25 gf / 25 mm or 1 gf / 25 mm to 20 gf / 25 mm and a high peel strength of 10 gf / 25 mm to 300 gf / 25 g / 25 mm to 200 gf / 25 mm, or 20 gf / 25 mm to 200 gf / 25 mm or 30 gf / 25 mm to 200 gf / 25 mm.

The term low-speed peeling force is, for example, the peeling force measured at a peeling angle of 180 degrees and a peeling speed of 0.3 m / min. The high-speed peeling force was measured at a peeling angle of 180 degrees and a peeling speed of 30 m / min It can be peeling force.

Specifically, each of the peel strengths was measured by attaching a pressure-sensitive adhesive composition having a crosslinked structure to an adherend having a surface energy of 30 mN / m or less, holding the layer at 23 ° C and 65% relative humidity for 24 hours, And may be one measured at each peeling angle and peeling speed. A specific method of measuring each of the peeling forces is described in the following examples.

The method of measuring the surface energy of the adherend is not particularly limited, and a known method of measuring the surface energy can be applied. For example, the contact angle of an adherend may be measured, the surface energy may be determined therefrom, or the surface energy may be measured using a known surface energy measuring device. The surface energy of the adherend may be, for example, about 10 m / N / m to 30 mN / m.

The pressure-sensitive adhesive composition may further have a ratio H / L of the high-speed peeling force H to the low-speed peeling force L of 1 to 30, 1 to 25, 1 to 20, 5 to 20, have.

The pressure-sensitive adhesive composition is also excellent in peeling electrification voltage, which is generated when the adherend, i.e., an adherend having a surface energy of 30 mN / m or less is peeled off at a peeling angle of 180 degrees and a peeling speed of 40 m / Can be 0.7 kV or less. The method of measuring the peeling electrification voltage is described in the following examples.

If the low-speed peeling force, the high-speed peeling force and / or the peeling electrification voltage are secured as described above, it can be easily peeled off at a high speed while minimizing the occurrence of static electricity while exhibiting an appropriate protection function for the adherend.

The present application is also directed to a pressure sensitive adhesive sheet. The adhesive sheet may be, for example, a protective film, specifically a protective film for an optical element.

For example, the pressure-sensitive adhesive sheet can be used as a protective film for an optical element such as a polarizing plate, a polarizer, a polarizer protective film, a retardation film, a viewing angle compensation film, and a brightness enhancement film. As used herein, the term polarizer and polarizer refers to objects that are distinguished from each other. That is, the polarizer refers to a film, sheet or device itself exhibiting a polarization function, and the polarizer refers to an optical element including other elements together with the polarizer. Other elements that can be included in the optical element together with the polarizer include, but are not limited to, a polarizer protective film or a retardation layer.

The pressure sensitive adhesive sheet may include, for example, a surface protecting base film and a pressure sensitive adhesive layer present on one side of the base film. The pressure-sensitive adhesive layer may include, for example, a pressure-sensitive adhesive composition that is crosslinked, that is, a pressure-sensitive adhesive composition having a crosslinked structure, as the pressure-sensitive adhesive composition.

The pressure-sensitive adhesive composition exhibits relatively high low-speed peeling force and relatively low high-speed peeling force after the crosslinked structure is implemented, and excellent balance between the peel strength and excellent durability reliability, workability, transparency and antistatic property. Thus, the protective film is used for protecting the surface of an optical element such as a polarizing plate, a retardation plate, an optical compensation film, a reflection sheet and a brightness enhancement film used for various optical devices or parts, display devices or parts such as LCD , But the use of the protective film is not limited to the use of the protective film.

As the surface protective base film, a general film or sheet known in this field can be used. For example, a polyester film such as polyethylene terephthalate or polybutylene terephthalate, a polytetrafluoroethylene film, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a poly (vinyl chloride) film or a polyimide film And the like. Such a film may be composed of a single layer, or two or more layers may be laminated, and in some cases, a functional layer such as an antifouling layer or an antistatic layer may further be included. From the viewpoint of improving the adhesion of the substrate, a surface treatment such as a primer treatment may be performed on one surface or both surfaces of the substrate.

The thickness of the base film may be suitably selected depending on the application and is not particularly limited, and may be generally formed to a thickness of 5 to 500 탆 or 10 to 100 탆.

The thickness of the pressure-sensitive adhesive layer included in the pressure-sensitive adhesive sheet is not particularly limited, and may be, for example, 2 m to 100 m or 5 m to 50 m.

The pressure-sensitive adhesive layer may have, for example, a gel content of about 80% to about 99%. The gel content can be calculated, for example, by the following equation (1).

[Equation 1]

Gel content = B / A x 100

In the formula 1, A represents the mass of the pressure-sensitive adhesive, and B represents the dry mass of the insoluble fractions recovered after immersing the pressure-sensitive adhesive in ethyl acetate at room temperature for 48 hours.

The pressure-sensitive adhesive layer may contain a resin component having a molecular weight (weight-average molecular weight or number-average molecular weight) of 5,000 or less, 4.5 wt% or less, 4 wt% or less, 3.5 wt% or less, 3 wt% Or less, 1.5 wt% or less, or 1 wt% or less. The lower the proportion of the resin component, the lower the staining property of the pressure-sensitive adhesive can be obtained, and the lower limit is not particularly limited. For example, the ratio may be greater than 0 wt% or greater than 0 wt%. In addition, the molecular weight of the resin component may be about 100 or more in another example.

The present application also relates to a method for producing said protective film.

The manufacturing method includes the steps of: preparing an acrylic pressure-sensitive adhesive resin solution having a molecular weight distribution of 5 or less by living radical polymerization; And forming a pressure-sensitive adhesive layer on the surface protective base layer using the pressure-sensitive adhesive resin solution.

The specific properties of the pressure-sensitive adhesive resin prepared above, the composition of the monomers, and the like are as described above.

Accordingly, in the above production process, the molecular weight distribution of the resin can be controlled to 5 or less, 4.5 or less, 4 or less, 3.5 or less, 3 or less, 2.5 or less or 2 or less by the living radical polymerization method in the process of producing the adhesive resin . In this case, the molecular weight distribution may be one or more.

In addition, in the above production method, the adhesive resin solution may have a proportion of a resin component having a molecular weight (weight average molecular weight or number average molecular weight) of 5,000 or less based on the solid content thereof is 5 wt% or less, 4.5 wt% or less, 3.5 wt% or less, 3 wt% or less, 2 wt% or less, 1.5 wt% or less, or 1 wt% or less. The lower the proportion of the resin component, the lower the staining property of the pressure-sensitive adhesive can be obtained, and the lower limit is not particularly limited. For example, the ratio may be greater than 0 wt% or greater than 0 wt%. In addition, the molecular weight of the resin component may be about 100 or more in another example.

A specific mode of the LRP (Living Radical Polymerization) method for producing the resin is not particularly limited, and a known method can be applied. For example, an atom transfer radical polymerization method (ATRP) using an atom transfer radical polymerization agent as a polymerization initiator, an ARGET method using an atom transfer radical polymerization agent as an polymerization initiator and performing polymerization under an organic or inorganic reducing agent that generates electrons (ATRP), Initiators for Continuous Activator Regeneration (ATRP), Atom Transfer Radical Polymerization (ATRP), Reversible Additonal Separation by Chain Transfer Agent (RAFT) or an organic tellurium compound as an initiator, but the present invention is not limited thereto.

The method of forming the pressure-sensitive adhesive layer using the pressure-sensitive adhesive resin solution prepared as described above is not particularly limited. For example, the pressure-sensitive adhesive layer can be formed through a coating and curing process using an adhesive coating solution prepared by blending other components such as a crosslinking agent into the solution.

A method in which the coating liquid is applied to a base film or the like by a conventional means such as a bar coater and cured or a method in which a pressure sensitive adhesive composition or coating solution is once coated on the surface of a releasable substrate and cured, Can be used.

The process of forming the pressure-sensitive adhesive layer is preferably performed after sufficiently removing the bubble-inducing component such as the volatile component or the reaction residue in the pressure-sensitive adhesive composition or the coating liquid. Accordingly, the crosslinking density or the molecular weight of the pressure-sensitive adhesive is too low to lower the elastic modulus, and bubbles existing between the glass plate and the pressure-sensitive adhesive layer at high temperature are increased to form scattering bodies therein.

Also, the method of curing the pressure-sensitive adhesive composition in the above process is not particularly limited. For example, the pressure-sensitive adhesive resin and the crosslinking agent contained in the composition may be subjected to an appropriate aging process to react them, For example, ultraviolet irradiation, or the like.

The present application is also directed to optical elements. An exemplary optical element may include an optical element and the adhesive sheet attached to the surface of the optical element. For example, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is attached to the surface of the optical element, so that the optical element can be protected by the surface-protecting base film.

As the optical element included in the optical element, for example, a polarizer, a polarizing plate, a polarizer protective film, a retardation layer or a viewing angle compensation layer can be exemplified.

As the polarizer, for example, general types known in the art such as polyvinyl alcohol polarizers and the like can be employed without limitation.

A polarizer is a functional film or sheet capable of extracting only light vibrating in one direction from incident light while vibrating in various directions. Such a polarizer may be, for example, a form in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. The polyvinyl alcohol-based resin constituting the polarizer can be obtained by, for example, gelling a polyvinyl acetate-based resin. In this case, the polyvinyl acetate-based resin that can be used may include not only a single-stick adhesive resin of vinyl acetate but also a co-adhesive resin of vinyl acetate and other monomers copolymerizable therewith. Examples of the monomer copolymerizable with vinyl acetate include monomers such as unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group, or a mixture of two or more thereof. no. The degree of gelation of the polyvinyl alcohol-based resin may be generally from 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol-based resin may be about 1,000 to 10,000, preferably about 1,500 to 5,000.

A polyvinyl alcohol-based resin may be formed and used as the original film of the polarizer. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and a general method known in this field can be used. The thickness of the original film formed of a polyvinyl alcohol-based resin is not particularly limited, and can be suitably controlled within a range of, for example, 1 m to 150 m. The thickness of the original film can be controlled to 10 mu m or more in consideration of easiness of drawing and the like. The polarizer is formed by a process of stretching a polyvinyl alcohol-based resin film as described above (e.g., uniaxial stretching), dyeing a polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, A process of treating a polyvinyl alcohol resin film with a boric acid aqueous solution and a process of washing with a boric acid aqueous solution after washing. As the dichroic dye, iodine or dichroic organic dyes may be used.

The polarizer may include, for example, the polarizer; And other optical films attached to one side or both sides of the polarizer. Examples of the other optical films include the above-described polarizer protective film, retardation layer, viewing angle compensation layer, antiglare layer, and the like.

The polarizer protective film is a protective film for a polarizer in a concept distinct from a protective film containing the pressure-sensitive adhesive layer. As the polarizer protective film, for example, a cellulose-based film such as triacetylcellulose; Acrylic film; Polyester-based films such as polycarbonate film or polyethylene terephthalate film; Polyethersulfone-based films; And a protective film composed of a polyethylene film, a polypropylene film, or a polyolefin film such as a polyolefin film having a cyclo or norbornene structure or an ethylene propylene co-adhesive resin, or the like. The thickness of the protective film is also not particularly limited, and can be formed in a usual thickness.

In the optical element, a surface treatment layer may be present on the surface of the optical element protected by the protective film. The surface treatment layer may have a surface energy of 30 mN / m or less, for example. That is, a surface treatment layer having a surface energy of 30 mN / m or less is formed on a surface of an optical element protected by the protective film in the optical element, and the pressure sensitive adhesive layer of the protective film is attached to the surface treatment layer .

The surface treatment layer may be a low reflection layer such as an anti-glare layer or an anti-reflection (AR) layer or a low reflection (LR) layer such as a hard layer, an anti-glare layer or a semi- Can be illustrated.

The high hardness layer may be a layer having a pencil hardness of at least 1H or 2H or more under a load of 500 g. Pencil hardness can be measured, for example, according to ASTM D 3363 specification using the pencil lead specified in KS G2603.

The high hardness layer may be, for example, a resin layer having a high hardness. The resin layer may include, for example, a room temperature curing type, a moisture curing type, a thermosetting type, or an active energy ray curing type resin composition in a cured state. In one example, the resin layer may include a thermosetting or active energy ray-curable resin composition, or an active energy ray-curable resin composition in a cured state. The term " cured state " in the description of the hardened layer means a case where the components contained in each of the resin compositions are converted into a hard state through a cross-linking reaction or a polymerization reaction. The above-mentioned room temperature curing type, moisture curing type, thermosetting type or active energy ray curable type resin composition can be prepared by heating the cured state at room temperature or by heating in the presence of appropriate humidity or irradiation of active energy rays ≪ / RTI > composition.

In this field, various resin compositions are known which can satisfy the pencil hardness in the above-mentioned range in a cured state, and an average person can easily select a suitable resin composition.

In one example, the resin composition may include an acrylic compound, an epoxy compound, a urethane compound, a phenol compound or a polyester compound as a main component. In the above, the "compound" may be a monomeric, oligomeric or adhesive resin compound.

In one example, an acrylic resin composition excellent in optical properties such as transparency and excellent in resistance to yellowing, for example, an active energy ray-curable acrylic resin composition can be used as the resin composition.

The active energy ray-curable acrylic composition may include, for example, an active energy ray-polymerizable adhesive resin component and a reactive diluting monomer.

Examples of the adhesive resin component include a component known as an actinic energy pre-polymerizable oligomer such as urethane acrylate, epoxy acrylate, ether acrylate or ester acrylate, or a monomer such as a (meth) acrylic acid ester monomer or the like Can be exemplified. Examples of the (meth) acrylic acid ester monomer include alkyl (meth) acrylate, (meth) acrylate having an aromatic group, heterocyclic (meth) acrylate or alkoxy (meth) acrylate. In this field, various pressure-sensitive adhesive resin components for producing an active energy ray-curable composition are known, and such compounds can be selected as needed.

Examples of the reactive diluting monomer which can be contained in the active energy ray-curable acrylic composition include monomers having one or more active energy ray-curable functional groups such as an acryloyl group or a methacryloyl group . As the reactive diluting monomer, for example, the above (meth) acrylic acid ester monomers, multifunctional acrylates, and the like can be used.

The selection of the above-mentioned components for forming the active energy ray-curable acrylic composition, the blending ratio of the selected components and the like are not particularly limited and can be adjusted in consideration of the hardness and other physical properties of the desired resin layer.

As the anti-glare layer such as the AG layer or the SG layer, for example, a resin layer in which an uneven surface is formed or a resin layer containing particles, wherein the resin is a particle layer having a refractive index different from that of the resin layer .

As the resin layer, for example, a resin layer used for forming the high hardness layer may be used. In the case of forming the anti-glare layer, it is not necessary to adjust the components of the resin composition so that the resin layer necessarily exhibits high hardness, but a resin layer may be formed so as to exhibit high hardness.

The method of forming the uneven surface on the resin layer is not particularly limited. For example, the resin composition may be cured in a state in which a coating layer of the resin composition is brought into contact with a metal mold having a desired concavo-convex structure, or particles having a particle diameter appropriate for the resin composition may be blended, have.

The anti-glare layer may also be formed using particles having different refractive indices from the resin layer.

In one example, the difference in refractive index between the particles and the resin layer may be 0.03 or less or 0.02 to 0.2, for example. If the difference in refractive index is too small, it is difficult to cause haze. On the contrary, if the refractive index difference is excessively large, scattering in the resin layer occurs a lot and haze increases, but deterioration of light transmittance or contrast characteristics may be induced. And appropriate particles can be selected.

The shape of the particles contained in the resin layer is not particularly limited and may be, for example, spherical, elliptical, polyhedral, amorphous or other shapes. The particles may have an average diameter of 50 nm to 5,000 nm. In one example, as the particles, particles having irregularities on the surface can be used. Such particles may have a mean surface roughness (Rz) of, for example, 10 nm to 50 nm or 20 nm to 40 nm, and / or a maximum height of irregularities formed on the surface of about 100 nm to 500 nm or 200 nm to 400 nm, and the width between the irregularities may be 400 nm to 1,200 nm or 600 nm to 1,000 nm. Such particles are excellent in compatibility with the resin layer and in dispersibility therein.

As the particles, various inorganic or organic particles can be exemplified. Examples of the inorganic particles include silica, amorphous titania, amorphous zirconia, indium oxide, alumina, amorphous zinc oxide, amorphous cerium oxide, barium oxide, calcium carbonate, amorphous barium titanate, barium sulfate, Examples of the organic particles include crosslinked or non-crosslinked particles of an organic material such as an acrylic resin, a styrene resin, a urethane resin, a melamine resin, a benzoguanamine resin, an epoxy resin or a silicone resin, It is not.

The concavo-convex structure or the content of the particles formed on the resin layer is not particularly limited. The shape of the concave-convex structure or the content of the particles may be controlled such that the haze of the AG layer is about 5% to 15%, 7% to 13%, or about 10% And in the case of the SG layer, the haze can be adjusted to be about 1% to 3%. The haze can be measured according to the manufacturer's manual using a hazemeter such as HR-100 or HM-150 of Sephiroth Co.,

A low reflection layer such as an AR layer or an LR layer can be formed by coating a low refractive material. A low refractive index material capable of forming a low reflection layer is variously known and can be suitably selected and used for the optical element. The low reflection layer can be formed to have a reflectance of about 1% or less through coating of a low refractive material.

The formation of the surface treatment layer may be carried out in the manner described in Korean Patent Publication Nos. 2007-0101001, 2011-0095464, 2011-0095004, 2011-0095820, 2000-0019116, 2000-0009647, 2000 -0018983, 2003-0068335, 2002-0066505, 2002-0008267, 2001-0111362, 2004-0083916, 2004-0085484, 2008-0005722, 2008-0063107 A material known in JP-A-2008-0101801 or JP-A-2009-0049557 can also be used.

The surface treatment layer may be formed singly, or two or more of them may be formed in combination. As an example of the combination, a case where a high hardness layer is first formed on the surface of the base layer and a low reflection layer is formed again on the surface of the base layer is exemplified.

The present application also relates to a display device, for example, a liquid crystal display (LCD). An exemplary display device may include a liquid crystal panel, and the optical element may be attached to one or both sides of the liquid crystal panel. The film may be attached to the liquid crystal panel using, for example, an adhesive or a pressure-sensitive adhesive. In the above, the adhesive or pressure-sensitive adhesive is an adhesive or a pressure-sensitive adhesive other than the pressure-sensitive adhesive present in the protective film described above.

The type of the liquid crystal panel included in the liquid crystal display device is not particularly limited. For example, the present invention is not limited to the type, but various passive matrix methods including TN (Twisted Neumatic) type, STN (Super Twisted Neumatic) type, F (ferroelectric) type and PD (polymer dispersed LCD) type; Various active matrix systems including two-terminal and three-terminal; Any known liquid crystal panel including a horizontal mode (IPS mode) panel and a vertical mode (VA mode) panel can be applied. The types of other structures included in the liquid crystal display device and the manufacturing method thereof are also not particularly limited, and general structures in this field can be employed without any limitations.

The pressure-sensitive adhesive sheet formed by using the pressure-sensitive adhesive composition of the present application exhibits an appropriate level of surface resistance and excellent peeling electrification characteristics, and does not leave any contamination on the adherend even after being peeled off after adhering to the adherend for a long time. The pressure-sensitive adhesive sheet using the pressure-sensitive adhesive composition of the present application can be applied to various applications, and can be used as a protective film for an optical member such as a polarizing plate.

Hereinafter, the pressure-sensitive adhesive composition will be described in more detail with reference to Examples and Comparative Examples, but the scope of the pressure-sensitive adhesive composition is not limited to the following examples.

1. Evaluation of molecular weight

The number average molecular weight (Mn) and the molecular weight distribution (PDI) were measured by GPC under the following conditions. The calibration curve was prepared using the standard polystyrene of the Aglient system.

<Measurement Conditions>

Measurer: Aglient GPC (Aglient 1200 series, U.S.)

Column: Two PL Mixed B connections

Column temperature: 40 ° C

Eluent: THF (Tetrahydrofuran)

Flow rate: 1.0 mL / min

Concentration: ~ 1 mg / mL (100 μL injection)

2. Low speed Exfoliation  Measure

The pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples were attached to the anti-glare layer of the polarizing plate on which the anti-glare layer was formed, using a roller of 2 Kg according to JIS Z 0237. Thereafter, the sample was stored at a temperature of 23 DEG C and a relative humidity of 65% for 24 hours, and then cut to a length of 25 mm and a length of 120 mm. Thereafter, the specimen was fixed to the glass substrate, and the peeling force was measured using a tensile tester while peeling the adhesive sheet from the anti-glare layer in a transverse direction at a peeling angle of 180 degrees and a peeling speed of 0.3 m / min. The peeling force was measured for two identical specimens and the average value was adopted.

3. High speed Exfoliation  Measure

The pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples were attached to the anti-glare layer of the polarizing plate on which the anti-glare layer was formed, using a roller of 2 Kg according to JIS Z 0237. Thereafter, after being stored at a temperature of 23 DEG C and a relative humidity of 65% for 24 hours, the specimen was cut by cutting to a length of 25 mm and a length of 250 mm. Thereafter, the specimen was fixed to the glass substrate, and the peeling force was measured while peeling the adhesive sheet from the anti-glare layer in the transverse direction at a peeling angle of 180 degrees and a peeling speed of 30 m / min using a tensile tester. The peeling force was measured for two identical specimens and the average value was adopted.

4. Measurement of stripping voltage (ESD)

The specimens were the same as those used for low speed and high speed peel force measurements, with a length of about 22 cm and a length of about 25 cm. Subsequently, the specimen was fixed to the glass substrate, and the peeling electrification voltage was measured while peeling off the adhesive sheet of the specimen with a tensile tester at a peeling angle of about 180 degrees and a peeling speed of 40 m / min.

5. Whether or not the stain occurred after removing the adhesive sheet

After peeling off the pressure-sensitive adhesive sheet from the same specimen as that used in the measurement of the low-speed peeling force, it was observed whether or not the surface of the adhered object was contaminated by static electricity.

<Evaluation Criteria>

A: Unevenness on the surface of the adherend

B: When the surface of the adherend is stained

Manufacturing example  1. Preparation of acrylic copolymer (A)

(EHA), 4-hydroxybutyl acrylate (HBA), 2-hydroxyethyl acrylate (HEA) and polyethylene glycol monomethyl ether methacrylate (number of moles of ethylene oxide: 9 mol) (PEGMA) in a weight ratio of 80: 2: 8: 10 (EHA: HBA: HEA: PEGMA) was synthesized in the following manner. 100 parts by weight of the above monomer mixture, 0.17 part by weight of 2-cyano-2-propyl benzodithioate, 0.05 part by weight of azobisisobutyronitrile, 0.1 part by weight of ethyl acetate, 100 parts by weight were added, the cap was sealed, and oxygen was removed through nitrogen bubbling for 30 minutes. The reaction flask was then immersed in an oil bath preheated to 60 &lt; 0 &gt; C to initiate the reaction. A sample was taken periodically to measure the conversion rate, and the reaction was terminated when the conversion rate reached 90% or more

Manufacturing example  2 to 4

A living radical polymer was prepared in the same manner as in Preparation Example 1 except that the proportion of the monomer components was controlled as shown in Table 1 below.

Manufacturing example One 2 3 4 A1 A2 A3 A4 acryl
cohesion
Suzy EHA 80 70 71 BA 10 63 HBA 2 One 4 2 HEA 8 9 35 PEGMA 10 15 DMAEA 10 Number average molecular weight (Mn) (x 10000) 10.1 15.6 28.1 65 Molecular weight distribution (PDI) 1.6 1.6 2.1 3.5 EHA: 2-ethylhexyl acrylate
BA: n-butyl acrylate
HBA: 4-hydroxyl butyl acrylate
HEA: 2-hydroxyethyl acrylate
DMAEA: Dimethylaminoethyl acrylate
PEGMA: polyethylene glycol monomethyl ether methacrylate (number of moles of ethylene oxide added: 9 moles)

Manufacturing example  5.

(BA), 4-hydroxybutyl acrylate (HBA), 2-hydroxyethylacrylate (HEA), and the like were added to a 1 L reactor equipped with a cooling device so that nitrogen gas was refluxed and temperature- Was added in a weight ratio of 63: 2: 35, and 100 parts by weight of ethyl acetate was added as a solvent to 100 parts by weight of the monomer. Next, nitrogen gas was purged for 1 hour to remove oxygen, and 0.1 part by weight of a reaction initiator (AIBN: azobisisobutyronitrile) was added thereto for about 8 hours. The reaction mixture was diluted with ethyl acetate to obtain an acrylic pressure- .

Manufacturing example  6.

A polymer was prepared in the same manner as in Production Example 5, except that the proportions of the monomer components were adjusted as shown in Table 2 below.

Manufacturing example 5 6 B1 B2 acryl
cohesion
Suzy EHA 71 BA 63 HBA 2 4 HEA 35 PEGMA 15 DMAEA Number average molecular weight (Mn) (x 10000) 35 98 Molecular weight distribution (PDI) 6.2 8.2 EHA: 2-ethylhexyl acrylate
BA: n-butyl acrylate
HBA: 4-hydroxyl butyl acrylate
HEA: 2-hydroxyethyl acrylate
DMAEA: Dimethylaminoethyl acrylate
PEGMA: polyethylene glycol monomethyl ether methacrylate (number of moles of ethylene oxide added: 9 moles)

Example  1 to 4 and Comparative Example  1 and 2

Preparation of pressure-sensitive adhesive composition

The pressure-sensitive adhesive resin, the crosslinking agent and the antistatic agent in each of the above-mentioned production examples were uniformly blended at the same weight ratios as shown in Table 3 below and diluted to a proper concentration in consideration of coating properties to prepare a pressure-sensitive adhesive composition.

Production of pressure-sensitive adhesive sheet

The pressure-sensitive adhesive composition thus prepared was coated on one side of a PET (poly (ethylene terephthalate)) film (thickness: 38 占 퐉) and dried to form a uniform coating layer having a thickness of about 20 占 퐉. Subsequently, the adhesive layer was maintained at about 90 DEG C for about 3 minutes to induce a crosslinking reaction on the coating layer to produce a pressure-sensitive adhesive sheet.

Example Comparative Example One 2 3 4 One 2 Acrylic adhesive resin A1 A2 A2 A3 B1 B2 Cross-linking agent 4.0 4.0 4.0 4.0 4.0 4.0 Antistatic agent A1 0.5 0.5 0.5 0.5 0.5 A2 0.5 Ratio unit: Acrylic adhesive resin 100 parts by weight
Crosslinking agent: MHG-80B, manufactured by Asahi
A1: lithium bistrifluoromethanesulfonylimide
A2: Methyl tributyl ammonium bistrifluoromethanesulfonylimide

The measured physical properties of each of the pressure-sensitive adhesive sheets prepared above are summarized in Table 4 below.

Example Comparative Example One 2 3 4 One 2 Peel force L 2.6 2.5 3.4 2.2 3.6 4.5 H 49 48 54 42 61 63 H / L 18 19 16 19 17 14 ESD 0.3 0.2 0.4 0.3 0.4 0.3 Stain occurrence A A A A B B L: Low-speed peel force (unit: gf / inch)
H: High-speed peel force (unit: gf / inch)
H / L: High rate of peeling force (H) Percentage of peeling force (L)
ESD: Peeling Voltage (Unit: kV)

Claims (15)

And an acrylic pressure-sensitive adhesive resin having a molecular weight distribution of 5 or less. The pressure-sensitive adhesive composition according to claim 1, wherein the acrylic pressure-sensitive adhesive resin is a living radical polymer (LRP). The pressure-sensitive adhesive composition according to claim 1, wherein the acrylic pressure-sensitive adhesive resin has a molecular weight in the range of 50,000 to 3,000,000. The pressure-sensitive adhesive composition according to claim 1, which comprises a resin component having a molecular weight of 5,000 or less in a proportion of 5% by weight or less. The pressure-sensitive adhesive composition according to claim 1, wherein the acrylic pressure-sensitive adhesive resin is a random copolymer or a block copolymer. The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive resin comprises a polymerization unit derived from a compound of the following formula (1) or a nitrogen-containing reactive compound:
[Chemical Formula 1]

Q is hydrogen or an alkyl group, U is an alkylene group, m is a number within the range of 0 to 20, and Z is hydrogen, an alkyl group or an aryl group. The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive resin comprises a polymerization unit derived from a compound represented by the following formula (2):
(2)

In Formula (2), Q is hydrogen or an alkyl group, A and B are each independently an alkylene group, and n is a number in the range of 0 to 10. The pressure-sensitive adhesive composition according to claim 1, further comprising a crosslinking agent. The pressure-sensitive adhesive composition according to claim 8, wherein the crosslinking agent comprises at least one selected from the group consisting of an aliphatic cyclic isocyanate compound and an aliphatic acyclic isocyanate compound. A surface protective substrate layer; And a pressure-sensitive adhesive layer formed on one surface or both surfaces of the base layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive composition of claim 1 in a crosslinked state. The surface-protective film according to claim 10, wherein the pressure-sensitive adhesive layer contains a resin component having a molecular weight of 5,000 or less in a proportion of 5% by weight or less. Preparing an acrylic adhesive resin solution having a molecular weight distribution of 5 or less by a living radical polymerization method; And forming a pressure-sensitive adhesive layer on the surface protective base layer using the pressure-sensitive adhesive resin solution. The method for producing a surface protective film according to claim 12, wherein the ratio of the resin component having a molecular weight of 5,000 or less contained in the acrylic adhesive resin solution is adjusted to 5 wt% or less. An optical element according to claim 10, wherein the protective film is attached to the surface so as to be peelable. A display device comprising the optical element of claim 14.