KR20200018556A - Pressure sensitive adhesive composition - Google Patents

Abstract

The present invention relates to an adhesive composition, a protective film, an optical element, and a display device. An adhesive sheet formed using the adhesive composition of the present invention exhibits an appropriate level of surface resistance and excellent peeling charging characteristics, and does not leave the contamination to an adherend even after peeling after adhering to the adherend for a long time. The adhesive sheet using the adhesive composition of the present invention can be applied to a variety of applications, for example, can be used as a protective film of an optical member, such as a polarizing plate.

Description

Adhesive composition {PRESSURE SENSITIVE ADHESIVE COMPOSITION}

The present application relates to an adhesive composition.

A protective film may be used to prevent dirt, such as dust, or scratches from occurring on optical elements such as polarizing plates, other plastic products, home appliances or automobiles. Protective films require proper peel strength and antistatic properties.

For example, when peeling a protective film at high speed for the use of a product or the assembly of another product, it is required that the peeling force (henceforth "high speed peeling force") is 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 speed should be relatively high to show an appropriate protective function.

In addition, foreign matters such as dust may be sucked by static electricity generated mainly when the protective film is peeled off, or, in the case of electronic products, electrostatic destruction or malfunction of the device may be caused. In particular, in recent years, as the accessories are integrated due to the spread of computers and the multi-functionality of liquid crystal TVs and mobile phones, the problem caused by static electricity has been further highlighted.

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 exists an attempt to mix | blend an ethylene oxide modified dioctyl plasticizer with an adhesive, and to suppress generation | occurrence | production of static electricity. In addition, in patent document 2, an organic salt is added to an adhesive, and in patent document 3, a metal salt and a chelating agent are mix | blended with an adhesive. However, according to the above methods, contamination by transfer of the pressure-sensitive adhesive component to the protected product occurs, or it is difficult to suppress static electricity generated at an early stage.

Japanese Laid-Open Patent Publication 1993-140519 Republic of Korea Patent Publication No. 2004-0030919 Korean Laid-Open Patent Publication No. 2006-0128659

The present application provides an adhesive composition. The pressure-sensitive adhesive sheet formed using the pressure-sensitive adhesive composition of the present application can exhibit an appropriate high speed and low speed peeling force and at the same time maintain a good balance between the two. 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 charging characteristics, and does not leave contamination with the adherend even after peeling after being adhered 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, for example, can be used as a protective film of an optical member such as a polarizing plate.

Exemplary pressure-sensitive adhesive composition may include an acrylic pressure-sensitive adhesive resin. As used herein, the term acrylic adhesive resin may have a property capable of forming an adhesive, and may mean a resin including 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. Included as a main component in the present application means that the proportion of the component is 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more by weight, or It may mean more than 95%. The upper limit of the ratio may be 100%.

The acrylic adhesive resin may have a molecular weight distribution of 5 or less. The term molecular weight distribution may mean the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn). In the present application, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are converted values for standard polystyrene (PS) measured by gel permeation chromatography (GPC). In another example, the molecular weight distribution may be 4.5 or less, 4 or less, 3.5 or less, 3 or less, 2.5 or less, or 2 or less. In addition, 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 use a resin produced by a LRP (Living Radical Polymerization) method. Resin synthesize | combined by the said LRP system shows narrow molecular weight distribution (PDI, Mw / Mn). Moreover, the said adhesive resin has few ratios of a low molecular weight component. Applying such an adhesive resin, for example, may be provided with an adhesive capable of minimizing contamination on the surface of the adherend after peeling.

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 produced by Living Radical Polymerization (LRP).

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

The pressure-sensitive adhesive resin has a molecular weight (weight average molecular weight or number average molecular weight) of 5,000 or less, and the proportion of the resin component is 5 wt% or less, 4.5 wt% or less, 4 wt% or less, 3.5 wt% or less, 3 wt% or less, 2 wt% Or less than 1.5% or less than or equal to 1% by weight. The lower the ratio of the resin component is, the lower the pressure-sensitive adhesive can be obtained, and the lower limit thereof is not particularly limited. For example, the ratio may be greater than or equal to 0 weight percent or greater than 0 weight percent. In addition, the molecular weight of the resin component may be about 100 or more in other examples.

As the adhesive resin, various kinds of adhesive resins can be used without particular limitation as long as the one of the above-described characteristics is shown.

In one example, the adhesive resin may include any one or two or more monomers of a monomer including an alkylene oxide chain, a nitrogen-containing reactive compound, and a hydroxy group-containing monomer as monomer components. As used herein, the term monomer refers to all kinds of compounds capable of forming an adhesive resin through a polymerization reaction. In addition, the fact that the adhesive resin includes a monomer as a monomer component may mean that the monomer is included in a state in which the monomers are polymerized to form side chains or main chains of the adhesive resin. In addition, unless otherwise specified herein, the adhesive resin may include, contain, or have any monomer, which may mean that the monomer is included, contains, or has a monomer.

As a monomer which has an alkylene oxide chain, the compound represented by following formula (1) can be illustrated, for example.

[Formula 1]

In Formula 1, Q is hydrogen or an alkyl group, U is an alkylene group, Z is a hydrogen, alkyl group or an aryl group, and m may be any number, for example, a number in the range of 0 to 20.

When two or more [—U—O—] units are present in Formula 1, the number of carbon atoms of U in the units may be the same or different.

M in Formula 1 is a number in the range of 0-20. Within this range, the polymerization efficiency and the crystallinity of the pressure sensitive adhesive resin can be maintained in an appropriate range during the production of the pressure sensitive adhesive resin, and appropriate conductivity can be given to the pressure sensitive adhesive. In particular, the effect of preventing contamination of the adherend within the above range can be maximized.

As used herein, unless otherwise specified, 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. The alkyl group may be linear, branched or cyclic. The alkyl group may be unsubstituted or substituted by one or more substituents.

As used herein, unless otherwise specified, the term alkylene group or alkylidene group may be 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, or 1 to 4 carbon atoms. have. The alkylene group or alkylidene group may be linear, branched or cyclic. The alkylene group or alkylidene group may be substituted by one or more substituents if necessary.

In Formula 1, Q may be an alkyl group, for example, an alkyl group having 1 to 8 carbon atoms or 1 to 4 carbon atoms. When using a compound in which Q is an alkyl group, for example, when the pressure-sensitive adhesive composition is applied to a protective film or the like, it may be advantageous that the protective film is easily removed without residues or stains on the adherend.

As used herein, unless otherwise specified, the term aryl group is condensed or bonded, including a benzene ring, or two or more benzene rings connected, or two or more benzene rings sharing one or two or more carbon atoms It may mean a monovalent residue derived from a compound or a derivative thereof containing the structure. 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. As such an aryl group, a phenyl group, phenylethyl group, phenylpropyl group, benzyl group, tolyl group, xylyl group or a naphthyl group can be illustrated.

As a substituent which may be substituted in a specific functional group, for example, the said alkyl group, the alkylidene group, or the alkylene group in this specification, an alkyl group, an alkoxy group, an alkenyl group, an epoxy group, a cyano group, a carboxyl group, acryloyl group, meta Cryloyl group, acryloyloxy group, methacryloyloxy group or aryl group may be exemplified, but is not limited thereto.

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

The kind of nitrogen-containing reactive compound which can be contained in an adhesive resin is not specifically limited. As used herein, the term nitrogen-containing reactive compound may mean a compound having at least one nitrogen atom and having a reactivity capable of polymerizing with another monomer forming an adhesive resin. As the compound, for example, an amide group-containing monomer, an amino group-containing monomer, an imide group-containing monomer or a cyano group-containing monomer may be used. As said amide group-containing monomer, it is (meth) acrylamide or N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, for example. , N-methylol (meth) acrylamide, diacetone (meth) acrylamide, N-vinylacetoamide, N, N'-methylenebis (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide , N, N-dimethylaminopropylmethacrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, or (meth) acryloyl morpholine and the like can be exemplified, and as the amino group-containing monomer, aminoethyl (meth) Acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like can be exemplified, and examples of the imide group-containing monomer include N-isopropylmaleimide, N Cyclohexylmaleimide or itaciconimide 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 ensure proper physical properties, for example, conductivity, and to secure excellent peeling properties, for example, a balance of low and high speed peeling force, and to maximize the effect of preventing contamination to the adherend, in particular, N, N- Dialkyl (meth) acrylamide can be used as said 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 also include a hydroxyl group containing monomer. The monomer may provide a hydroxyl group to the adhesive resin.

As a hydroxyl group containing monomer, the monomer represented by following formula (2) can be illustrated, for example.

[Formula 2]

In Formula 2, Q is hydrogen or an alkyl group, A and B are each independently an alkylene group, and n is any number, for example, a number from 0 to 10.

When two or more [—O—B—] units are present in Formula 2, the carbon number of B in the units may be the same or different.

In Formula 2, A and B may be each independently a linear alkylene group.

As a compound of Formula (2), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate , 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate or 2-hydroxypropylene glycol (meth) acrylate, and the like can be exemplified, but is not limited thereto.

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

For example, the adhesive resin is represented by Formula 2 and is present in A and B of Formula 2 while being represented by Formula 2 and the first monomer having the number of carbons of the alkylene group in A and B of Formula 2 being in the range of 1 to 3. The number of carbon of the alkylene group to include 4 to 20, 4 to 16, 4 to 12, 4 to 8 or 4 to 6 may include a polymer unit of the second monomer.

As such, when calculating the number of carbons to distinguish the first and second monomers, only the number of carbons of the alkylene group formed in the straight chain form is considered. For example, the substituents containing carbon in A and B are substituted. In this case, the carbon number of the substituent is not considered. Thus, through the polymerization unit of the two kinds of hydroxy monomers, a pressure-sensitive adhesive excellent in particularly excellent peel force characteristics, that is, the balance of high-speed and low-speed peel force can be provided. In addition, a pressure-sensitive adhesive composition which can reduce contamination to the adherend through appropriate control of the ratio of the monomer may be provided.

The ratio of the weights of the first and second monomers in the adhesive resin may be adjusted in order to secure peeling properties, that is, excellent balance of low speed and high speed peeling force, while ensuring various physical properties such as adhesive performance. For example, the ratio (A / B) of the weight (A) of the first monomer and the weight (B) of the second monomer in the adhesive resin may be one or more or more than one. In another example, the ratio may be at least about 1.1 or at least 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 performance within the range of such a ratio and exhibits an appropriate balance of high speed and low speed peeling force without leaving contaminants during peeling.

The pressure-sensitive adhesive resin may include any one or two or more of the monomers described above. In one example, in the case of including all of the monomers, the adhesive resin may include 0.1 to 5 parts by weight of the monomer of Formula 1, 1 to 30 parts by weight of the polymerization unit 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 may be included as a monomer component. Unless otherwise specified in the present specification, the unit weight part may mean a ratio of weight between each component. For example, the pressure-sensitive adhesive resin is 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 monomer components. Included is the ratio of the weight (A) of the monomer of Formula 1, the weight (B) of the nitrogen-containing reactive compound, the weight (C) of the first monomer and the weight (D) of the second monomer (A: B: C: It can mean that the said adhesive resin was formed from the mixture of the monomer containing each said monomer so that D) may become "0.1-5: 1-30: 0.1-15: 0.1-5". 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. In addition, the nitrogen-containing reactive monomer may be included in 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. The pressure-sensitive adhesive composition can be provided that exhibits a suitable high-speed and low-speed peeling force within the ratio range of the monomer as described above, while maintaining a good balance between the two. In addition, the pressure-sensitive adhesive composition may be provided by using the pressure-sensitive adhesive resin, which exhibits an appropriate level of surface resistance and excellent peeling charging characteristics, and does not leave contamination to the adherend even after peeling after being attached to the adherend for a long time. If necessary, the weight ratio (E) of the monomer of Formula 1 and the weight ratio (N) of the nitrogen-containing reactive compound in the adhesive resin may be further adjusted, for example, the ratio (N / E) of the weight is about 0.1 to 10, about 0.1 to 9, about 0.1 to 8, about 0.1 to 7, about 0.1 to 6, about 0.1 to 5, about 0.1 to 4, about 0.1 to 3, about 0.5 to 3 or about 0.5 to 2 Can be adjusted within.

The adhesive resin may also further comprise polymerized units of (meth) acrylic acid ester monomers, for example alkyl (meth) acrylates.

As alkyl (meth) acrylate, the alkyl (meth) acrylate which has a C1-C14 alkyl group can be used in consideration of cohesion force, glass transition temperature, or adhesiveness of an adhesive, for example. Such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) Acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (Meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, and the like can be exemplified, and one or two or more of the above are polymerized units to an adhesive resin. It may be included as.

The adhesive resin may include 65 parts by weight to 99 parts by weight or 70 parts by weight to 90 parts by weight of polymerized units of the (meth) acrylic acid ester monomer. The weight ratio may be changed, for example, in consideration of the specific type of each monomer and the like as necessary.

The said adhesive resin is a well-known monomer used for manufacture of the adhesive resin of an adhesive, for example, (meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy, if necessary Carboxyl group-containing monomers such as propyl acid, 4- (meth) acryloyloxy butyric acid, acrylic acid duplex, itaconic acid, maleic acid and maleic anhydride; Radical polymerizable containing a monomer having an isocyanate group, a monomer having a glycidyl group such as glycidyl (meth) acrylate, or a nitrogen atom such as (meth) acrylamide, N-vinyl pyrrolidone or N-vinyl caprolactam, etc. It may further include a radical polymerizable monomer such as a monomer or styrene. Such monomers may be polymerized to be included in the adhesive resin, and for example, may be included in the adhesive resin in a ratio of about 20 parts by weight or less.

Adhesive resin can be manufactured by selecting the required monomer from the above-mentioned monomers, and applying the mixture of the monomer which mix | blended the selected monomer in the target ratio to LRP (Living Radical Polymerization) system.

The pressure-sensitive adhesive composition may include a light stabilizer, for example, a light stabilizer such as a hindered amine compound. Such light stabilizers are not aggregated even when the pressure sensitive adhesive is left at high temperature, for example, so that the concentration of the antistatic agent described later in the aggregated cluster does not increase, and the alkylene oxide contained in the pressure sensitive adhesive resin is included. The ether binding site of the chain is decomposed by heat to generate radicals, or the hydroxyl group-containing monomer can be prevented from causing a condensation reaction, thereby greatly improving the storage stability of the pressure-sensitive adhesive composition.

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

As a crosslinking agent, an aliphatic isocyanate crosslinking agent can be used, for example. When such a crosslinking agent implements a crosslinked structure with the pressure-sensitive adhesive resin, that is, the pressure-sensitive adhesive resin including two or more hydroxyl group-containing monomers, a pressure-sensitive adhesive having a necessary antistatic property with suitable low speed and high speed peeling force may be realized. For example, as a crosslinking agent, the crosslinking agent containing an aliphatic cyclic isocyanate compound and / or an aliphatic acyclic isocyanate compound can be used. As used herein, the term aliphatic cyclic isocyanate compound means an isocyanate compound that includes a ring structure, but the structure does not correspond to an aromatic ring, and the aliphatic acyclic isocyanate compound is, for example, an aliphatic linear or It may mean a branched isocyanate compound. As the aliphatic cyclic isocyanate compound, for example, isocyanate compounds such as isophorone diisocyanate or methylene dicyclohexyl diisocyanate or cyclohexane diisocyanate, and the like Derivatives such as dimers or trimers, or reactants of any of the above with polyols (ex. Trimethylolpropane) may be exemplified, and aliphatic acyclic isocyanate compounds include carbon atoms such as hexamethylene diisocyanate and the like. Alkylene diisocyanate compounds having from 20 to 20 carbon atoms, 1 to 12 carbon atoms or 1 to 8 carbon atoms, derivatives thereof such as dimers or trimers, or any of the above and polyols (ex. Reactant with propane) Etc. may be exemplified, but is not limited thereto.

In the case where 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 necessary. Typically, about 1 part by weight to about 500 parts by weight or about 20 parts by weight to about 300 parts by weight of the 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. Examples thereof include MHG-80B manufactured by Asahi and NZ-1 manufactured by Duranate P or BAYER. There is this.

As a crosslinking agent, if necessary further above, ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'- tetraglycidyl ethylenediamine or glycerin Epoxy crosslinking agents such as diglycidyl ether and the like; N, N'-toluene-2,4-bis (1-aziridinecarboxamide), N, N'-diphenylmethane-4,4'-bis (1-aziridinecarboxamide), triethylene melamine Aziridine crosslinkers such as bisisoprotaloyl-1- (2-methylaziridine) or tri-1-aziridinylphosphineoxide or aluminum, iron, zinc, tin, titanium, antimony, magnesium and / or vanadium A well-known crosslinking agent, such as a metal chelate crosslinking agent which is a compound in which a polyvalent metal like this is coordinated with acetyl acetone, ethyl acetoacetate, etc. can be used together.

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. An appropriate crosslinked structure can be realized in this range, and the low speed and high speed peeling force of the pressure-sensitive adhesive can be adjusted to the desired range.

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

As the ionic compound, for example, a metal salt can be used. The metal salt may include, for example, an alkali metal cation or an alkaline earth metal cation. As the cation, lithium ions (Li ⁺ ), sodium ions (Na ⁺ ), potassium ions (K ⁺ ), rubidium ions (Rb ⁺ ), cesium ions (Cs ⁺ ), beryllium ions (Be ²⁺ ), magnesium ions ( Mg ²⁺ ), calcium ions (Ca ²⁺ ), strontium ions (Sr ²⁺ ), and barium ions (Ba ²⁺ ) may be exemplified by one or two or more kinds thereof. For example, lithium ions, sodium ions, Lithium ions may be used in consideration of one or more kinds of potassium ions, magnesium ions, calcium ions, and barium ions, or ionic 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- ), carboxybenzenesulfonate (COOH (C ₆ H ₄ ) SO ₃ ⁻ ), trichloromethanesulfonate (CF ₃ SO ₂ ⁻ ), benzoate (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 -) or the like can be illustrated.

In another example, an anion or bisfluorosulfonylimide represented by the following Chemical Formula 5 may be used as the anion.

[Formula 5]

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

In formula (5), 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, n is 2 or 3.

In Formula 5, when Y is carbon, m is 1, when Y is sulfur, m is 2, n is 2 when X is nitrogen, and n may be 3 when X is carbon.

Anions or bis (fluorosulfonyl) imides of formula (5) exhibit high electronegativity due to perfluoroalkyl groups (R _f ) or fluorine groups, and also include unique resonance structures, forming weak bonds with cations At the same time, it has hydrophobicity. Therefore, while an ionic compound shows the outstanding compatibility with other components of compositions, such as adhesive resin, it can provide high antistatic property even in a small amount.

R _f of 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, in which case the perfluoroalkyl group is linear, branched or It may have a cyclic structure. The anion of Formula 5 may be a sulfonyl metide, sulfonylimide, carbonyl metide, or carbonyl imide anion, and specifically, tristrifluoromethanesulfonylmethide and bistrifluoromethanesulfide Ponylimide, bisperfluorobutanesulfonylimide, bispentafluoroethanesulfonylimide, tristrifluoromethanecarbonylmide, bisperfluorobutanecarbonylimide or bispentafluoroethanecarbonyl It may be a kind of imide or the like or a mixture of two or more thereof.

As the ionic compound, for example, as a cation, N-ethyl-N, N-dimethyl-N-propylammonium, N, N, N-trimethyl-N-propylammonium, N-methyl-N, N, N -Tributylammonium, N-ethyl-N, N, N-tributylammonium, N-methyl-N, N, N-trihexylammonium, N-ethyl-N, N, N-trihexylammonium, N-methyl Quaternary ammonium, such as -N, N, N-trioctylammonium or N-ethyl-N, N, N-trioctylammonium, phosphonium, pyridinium, imidazolium, An organic salt containing pyrolidinium, piperidinium, or the like together with the anion component may be used, or the metal salt and the organic salt may be used in combination if necessary.

The content of the ionic compound in the pressure-sensitive adhesive composition is not particularly limited, for example, may be present in a ratio of 0.01 parts by weight to 5 parts by weight with respect to 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 components.

The pressure-sensitive adhesive composition may further include a silane coupling agent. Examples of the coupling agent include gamma-glycidoxypropyl triethoxy silane, gamma-glycidoxypropyl trimethoxy silane, gamma-glycidoxypropyl methyldiethoxy silane, gamma-glycidoxypropyl triethoxy silane , 3-mercaptopropyl trimethoxy silane, vinyltrimethoxysilane, vinyltriethoxy silane, gamma-methacryloxypropyl trimethoxy silane, gamma-methacryloxy propyl triethoxy silane, gamma-aminopropyl tri Methoxy silane, gamma-aminopropyl triethoxy silane, 3-isocyanato propyl triethoxy silane, gamma-acetoacetate propyl trimethoxysilane, gamma-acetoacetate propyl triethoxy silane, beta-cyanoacetyl Trimethoxy silane, beta-cyanoacetyl triethoxy silane, acetoxyaceto trimethoxy silane, and one or more kinds of the above may be used. Can be. For example, it may be appropriate to use a silane coupling agent having an acetoacetate group or a beta-cyanoacetyl group as the silane coupling agent. The silane coupling agent may be included in the pressure-sensitive 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 pressure-sensitive adhesive resin. Appropriate adhesive strength increase effect and durability can be secured in the above range.

The pressure-sensitive adhesive composition may further include a tackifier in view of control of adhesion performance. As a tackifier, hydrocarbon resin or its hydrogenated substance, rosin resin or its hydrogenated substance, rosin ester resin or its hydrogenated substance, terpene resin or its hydrogenated substance, terpene phenol resin or its hydrogenated substance, polymeric rosin resin or polymeric rosin One kind or a mixture of two or more kinds such as an ester resin can be used. A 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. Suitable addition effect and compatibility and cohesive force improvement effect can be secured in the said content range.

The pressure-sensitive adhesive composition may also include a coordinating compound, a photoinitiator, a polyfunctional acrylate, an epoxy resin, a crosslinking agent, a UV stabilizer, an antioxidant, which can form a coordinating bond with the antistatic agent within a range that does not affect the effect of the application. It may further comprise one or more additives selected from the group consisting of colorants, reinforcing agents, fillers, antifoams, surfactants and plasticizers.

The pressure-sensitive adhesive composition has a low-speed peeling force of about 1 gf / 25 mm to 40 gf / 25mm, 1 gf / 25mm to 35 gf / 25mm for an adherend having a surface energy of 30 mN / m or less in a crosslinked structure. 1 gf / 25mm to 30 gf / 25mm, 1 gf / 25mm to 25 gf / 25mm or 1 gf / 25mm to 20 gf / 25mm, high speed peeling force 10 gf / 25mm to 300 gf / 25mm, 10 gf / 25mm To 250 gf / 25mm, 10 gf / 25mm to 200 gf / 25mm, 20 gf / 25mm to 200 gf / 25mm or 30 gf / 25mm to 200 gf / 25mm.

As used herein, the term low speed peel force is a peel force measured at a peel angle of 180 degrees and a peel rate of 0.3 m / min, and a high speed peel force is measured at a peel angle of 180 degrees and a peel rate of 30 m / min. May be a peel force.

Specifically, the peeling force of the adhesive composition is obtained by attaching the pressure-sensitive adhesive composition having a crosslinked structure to an adherend having a surface energy of 30 mN / m or less, and maintaining it at a temperature of 23 ° C. and a relative humidity of 65% for 24 hours. It may be measured at each peeling angle and peeling rate. The specific way of measuring each peel force 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 may be applied. For example, the contact angle of an adherend can be measured and surface energy can be calculated | required from this, or it can measure using a well-known surface energy measuring equipment. The surface energy of the adherend may be, for example, about 10 m / N / m to about 30 mN / m.

The pressure-sensitive adhesive composition may also 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, or 7 to 20. have.

The pressure-sensitive adhesive composition is also a peeling electrification voltage generated when peeling at a peel angle of 180 degrees and a peel rate of 40 m / min from the adherend, that is, the adherend having a surface energy of 30 mN / m or less in a state where a crosslinked structure is realized. May be 0.7 kV or less. The measuring method of the peeling electrification voltage is described in the following Examples.

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

The present application also relates to an adhesive sheet. The said adhesive sheet can be a protective film, specifically, the protective film for optical elements.

For example, the adhesive sheet can be used as a protective film for optical elements, 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 terms polarizer and polarizer refer to objects that are distinguished from each other. In other words, the polarizer refers to a film, sheet or device itself exhibiting a polarizing function, and the polarizing plate means an optical element including other elements together with the polarizer. As other elements that may be included in the optical device together with the polarizer, a polarizer protective film or a retardation layer may be exemplified, but is not limited thereto.

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

The pressure-sensitive adhesive composition exhibits a relatively high low-speed peeling force and a relatively low high-speed peeling force after the crosslinking structure is implemented, and is excellent in balance between both peeling forces, and has excellent durability, workability, transparency, and antistatic property. Accordingly, the protective film protects the surface of optical elements such as polarizing plates, retardation plates, optical compensation films, reflecting sheets, and luminance enhancing films used in various optical devices or components or display devices or components, for example, LCDs. Although it can be effectively used as a surface protective film for, the use is not limited to the protective film.

As the surface protective base film, a general film or sheet known in the art may be used. For example, polyester films such as polyethylene terephthalate or polybutylene terephthalate, polytetrafluoroethylene film, polyethylene film, polypropylene film, polybutene film, polybutadiene film, poly (vinyl chloride) film or polyimide film Plastic films such as Such a film may consist of a single layer, or two or more layers may be laminated, and in some cases, may further include a functional layer such as an antifouling layer or an antistatic layer. In addition, from the standpoint of improving substrate adhesion, surface treatment such as primer treatment may be performed on one or both surfaces of the substrate.

The thickness of the base film is not particularly limited as it is appropriately selected depending on the use, and can be generally formed in a thickness of 5 μm to 500 μm or 10 μm to 100 μm.

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 μm to 100 μm or 5 μm to 50 μm.

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

[Equation 1]

Gel content = B / A × 100

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

In addition, the pressure-sensitive adhesive layer is 5% by weight, 4.5% by weight, 4% by weight, 3.5% by weight, 3% by weight, 2% by weight of a resin component having a molecular weight (weight average molecular weight or number average molecular weight) of 5,000 or less. It may include up to%, 1.5% by weight or less than 1% by weight. The lower the ratio of the resin component is, the lower the pressure-sensitive adhesive can be obtained, and the lower limit thereof is not particularly limited. For example, the ratio may be greater than or equal to 0 weight percent or greater than 0 weight percent. In addition, the molecular weight of the resin component may be about 100 or more in other examples.

The present application also relates to a method of producing the protective film.

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

Specific characteristics of the pressure-sensitive adhesive resin prepared above, the composition of the monomer and the like are as described above.

Therefore, in the manufacturing method, the molecular weight distribution of the resin may 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 a living radical polymerization method in the process of preparing the adhesive resin. . In this case, the molecular weight distribution may be one or more.

In the above production method, the pressure-sensitive adhesive resin solution 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 based on the solid content of 5% by weight or less, 4.5% by weight or less, 4% by weight or less, It may be controlled to be 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 ratio of the resin component is, the lower the pressure-sensitive adhesive can be obtained, and the lower limit thereof is not particularly limited. For example, the ratio may be greater than or equal to 0 weight percent or greater than 0 weight percent. In addition, the molecular weight of the resin component may be about 100 or more in other examples.

The specific aspect of the LRP (Living Radical Polymerization) method of manufacturing the resin is not particularly limited, and a known method may be applied. For example, ARGET which performs polymerization under an organic or inorganic reducing agent which generates electrons by using atomic transfer radical polymerization (ATRP) using an atomic transfer radical polymerizing agent as a polymerization control agent, and an atomic transfer radical polymerization agent as a polymerization control agent. Activators Regenerated by Electron Transfer (ATRP), Initiators for Continuous Activator Regeneration (ICAR) Atomic Radical Polymerization (ATRP), Reversible Addition-Opening Chain Transfer Using Reversible Addition-Open Chain Transfer Or an organic tellurium compound as an initiator, but is not limited thereto.

The method for 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 may be formed through a coating and curing process using a pressure-sensitive adhesive coating solution prepared by mixing other components such as a crosslinking agent in the solution.

For example, a method of applying the coating solution to a base film or the like by means of a conventional bar coater or the like and curing, or applying the pressure-sensitive adhesive composition or the coating solution to the surface of the peelable base material once, curing it, and transferring it to the base film again, etc. Can be used

The formation process of the pressure-sensitive adhesive layer is preferably performed after sufficiently removing the bubble-inducing component such as volatile components or reaction residues in the pressure-sensitive adhesive composition or coating solution. Accordingly, the crosslinking density or molecular weight of the pressure-sensitive adhesive is too low, the elastic modulus is lowered, the bubbles existing between the glass plate and the pressure-sensitive adhesive layer in a high temperature state can be increased to prevent the problem of forming a scattering body therein.

In addition, the method of curing the pressure-sensitive adhesive composition in the above process is also not particularly limited, and for example, the adhesive resin and the crosslinking agent included in the composition may be subjected to an appropriate aging process or to induce activation of a photoinitiator. It may be carried out through light irradiation, for example ultraviolet light irradiation.

The present application also relates to an optical device. An exemplary optical element may include an optical element and the adhesive sheet attached to a 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, and thus the optical element may be protected by the surface protection base film.

As an optical element contained in an optical element, a polarizer, a polarizing plate, a polarizer protective film, a retardation layer, a viewing angle compensation layer, etc. can be illustrated, for example.

As the polarizer as described above, for example, a general kind known in the art such as polyvinyl alcohol polarizer can be employed without limitation.

The 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 in a polyvinyl alcohol-based resin film. Polyvinyl alcohol-type resin which comprises a polarizer can be obtained by gelatinizing polyvinylacetate-type resin, for example. In this case, the polyvinylacetate-based resin that can be used may include not only a single adhesive resin of vinyl acetate but also a co-adhesive resin of vinyl acetate and other monomers copolymerizable with the above. Examples of the monomer copolymerizable with vinyl acetate include one or two or more kinds of unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and acrylamides having an ammonium group, but are not limited thereto. no. The degree of gelation of the polyvinyl alcohol-based resin is usually about 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be further modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. In addition, 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.

Polyvinyl alcohol-type resin is formed into a film, and can be used as a raw film of a polarizer. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and a general method known in the art can be used. The thickness of the raw film formed into a polyvinyl alcohol-based resin is not particularly limited, and may be appropriately controlled within, for example, 1 µm to 150 µm. In consideration of ease of stretching and the like, the thickness of the master film can be controlled to 10 ㎛ or more. The polarizer is a step of stretching (ex. Uniaxial stretching) the polyvinyl alcohol resin film as described above, a step of dyeing the polyvinyl alcohol resin film with a dichroic dye, adsorbing the dichroic dye, and a dichroic dye adsorbed. The polyvinyl alcohol-based resin film can be produced through a process of treating with a boric acid aqueous solution and a process of washing with water after treating with a boric acid aqueous solution. As the dichroic dye, iodine or a dichroic organic dye may be used.

The polarizing plate may include, for example, the polarizer; And it may include another optical film attached to one side or both sides of the polarizer. As another optical film, the above-described polarizer protective film, a retardation layer, a viewing angle compensation layer, an antiglare layer, and the like can be exemplified.

A polarizer protective film is a protective film with respect to a polarizer by the concept distinguished from the protective film containing the said adhesive layer in the above. As a polarizer protective film, For example, Cellulose-type films, such as triacetyl cellulose; Acrylic film; Polyester film such as polycarbonate film or polyethylene terephthalate film; Polyether sulfone-based film; And / or a polyethylene film, a polypropylene film, or a polyolefin film having a cyclo- or norbornene structure, or a polyolefin-based film such as ethylene propylene co-adhesive resin, or the like. The thickness of the protective film is also not particularly limited, and may be formed in a conventional thickness.

In the optical device, a surface treatment layer may exist on the surface of the optical device protected by the protective film. For example, the surface treatment layer may have a surface energy of 30 mN / m or less. That is, a surface treatment layer having a surface energy of 30 mN / m or less is formed on the surface of the 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. Can be.

The surface treatment layer may include a high hardness layer, an anti-glare layer such as an AG (anti-glare) layer or a semi-glare (SG) layer, or a low reflection layer such as an anti reflection (AR) layer or a low reflection (LR) layer. May be exemplified.

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

The high hardness layer may be, for example, a high hardness resin layer. The resin layer may include, for example, a room temperature curing type, a moisture curing type, a thermosetting type, or an active energy ray curable 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. In the description of the high hardness layer, the "cured state" may mean a case in which the components contained in the respective resin compositions are converted into a hard state through a crosslinking reaction or a polymerization reaction. In addition, the above-mentioned room temperature curing type, moisture curing type, thermosetting type or active energy ray-curable resin composition, the curing state is induced at room temperature, or in the presence of suitable moisture, can be induced by the application of heat or irradiation of active energy rays. By composition may be meant.

In this field, various resin compositions are known which can satisfy the pencil hardness in the above-mentioned range in the cured state, and the average technician 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, a polyester compound, or the like as a main material. In the above, the "compound" may be a monomeric, oligomeric or adhesive resinous compound.

In one example, as the resin composition, 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.

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

The adhesive resin component may include a component known in the art as a so-called active energy ray polymerizable oligomer such as urethane acrylate, epoxy acrylate, ether acrylate or ester acrylate, or a monomer such as (meth) acrylic acid ester monomer or the like. Polymerized mixtures can be exemplified. Examples of the (meth) acrylic acid ester monomers include alkyl (meth) acrylates, (meth) acrylates having aromatic groups, heterocyclic (meth) acrylates or alkoxy (meth) acrylates. Various adhesive resin components for producing an active energy ray-curable composition are known in this field, and such compounds may be selected as necessary.

As the monomer for reactive dilution, which may be included in the active energy ray-curable acrylic composition, a monomer having one or two or more active energy ray-curable functional groups, for example, acryloyl group or methacryloyl group, may be exemplified. . As the monomer for reactive dilution, for example, the (meth) acrylic acid ester monomer or polyfunctional acrylate may be used.

The selection of the above components or the blending ratio of the selected components for producing the active energy ray-curable acrylic composition is not particularly limited, and may be adjusted in consideration of the hardness and other physical properties of the desired resin layer.

As an anti-glare layer such as an AG layer or an SG layer, for example, a resin layer containing a resin layer or particles having an uneven surface formed therein, or a resin layer in which the particles have particles having a refractive index different from that of the resin layer can be used. Can be.

As said resin layer, the resin layer used for formation of the said high hardness layer can be used as said, for example. When forming an anti-glare layer, although it is not necessary to adjust the component of a resin composition so that a resin layer may show high hardness, you may form a resin layer so that a high hardness may be shown.

The method of forming the uneven surface on the resin layer is not particularly limited. For example, the concave-convex structure can be realized by curing the resin composition in a state in which the coating layer of the resin composition is brought into contact with a mold having a desired concave-convex structure, or by mixing, coating and curing particles of an appropriate particle size in the resin composition. have.

The anti-glare layer may also be implemented using particles having a refractive index different from that of the resin layer.

In one example, the particles, for example, the difference in refractive index with the resin layer may be 0.03 or less or 0.02 to 0.2. If the difference in the refractive index is too small, it is difficult to cause haze, and if the difference is too large, scattering in the resin layer may occur, increasing haze, but deterioration of light transmittance or contrast characteristics may be induced. Consideration can be given to appropriate particles.

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, particles having irregularities formed on the surface can be used as the particles. Such particles have, for example, an average surface roughness (Rz) of 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 of the unevenness 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 or 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 or barium sulfate, and the like. Examples of the organic particles may include particles including a crosslinked or non-crosslinked material 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, but are not limited thereto. It is not.

The content of the uneven structure or the particles formed in the resin layer is not particularly limited. The shape of the uneven structure or the content of the particles, for example, in the case of the AG layer, so that the haze of the resin layer is about 5% to 15%, 7% to 13% or about 10%. In the case of the SG layer, the haze may be adjusted to be about 1% to 3%. The haze can be measured according to the manufacturer's manual using a hazemeter such as Sepung's HR-100 or HM-150.

The low reflection layer, such as an AR layer or an LR layer, may be formed by coating a low refractive material. There are various known low refractive materials that can form a low reflection layer, all of which may be appropriately selected and used for the optical element. The low reflection layer may be formed such that the reflectance is about 1% or less through the coating of the low refractive material.

In the formation of the surface treatment layer, Korean Unexamined Patent Publication Nos. 2007-0101001, 2011-0095464, 2011-0095004, 2011-0095820, 2000-0019116, 2000-0009647, and 2000 -0018983, 2003-0068335, 2002-0066505, 2002-0008267, 2001-0111362, 2004-0083916, 2004-0085484, 2008-0005722, 2008-0063107 The materials known from Japanese Patent Application No. 2008-0101801 or 2009-0049557 may also be used.

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

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

The kind of liquid crystal panel contained in a liquid crystal display device is not specifically limited. For example, F various passive matrix systems including, but not limited to, TN (Twisted Neumatic), STN (Super Twisted Neumatic), F (ferroelectric), PD (polymer dispersed LCD), and the like; Various active matrix schemes including two terminals and three terminals; Both known liquid crystal panels, including IPS mode panels and VA mode panels, can be applied. In addition, the kind and other manufacturing methods of other components included in the liquid crystal display device are not particularly limited, and general configurations in this field can be employed without limitation.

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 charging characteristics, and does not leave contamination with the adherend even after peeling after being adhered to the adherend for a long time. The pressure-sensitive adhesive sheet using the pressure-sensitive adhesive composition of the present application may be applied to various applications, for example, may be used as a protective film of 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. Molecular weight evaluation

The number average molecular weight (Mn) and molecular weight distribution (PDI) were measured under the following conditions using GPC. For the preparation of the calibration curve, the measurement results were converted using standard polystyrene of the Aglient system.

<Measurement condition>

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

Column: Connect 2 PL Mixed B

Column temperature: 40 ℃

Eluent: THF (Tetrahydrofuran)

Flow rate: 1.0mL / min

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

2. Measurement of low speed peeling force

The 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 with a roller of 2 Kg according to JIS Z 0237. Thereafter, after storing for 24 hours at a temperature of 23 ℃ and a relative humidity of 65%, the specimen was prepared by cutting to a length of 25 mm and a length of 120 mm. Thereafter, the test piece was fixed to the glass substrate, and the peel force was measured while peeling the adhesive sheet from the antiglare layer in the horizontal direction at a peel angle of 180 degrees and a peel rate of 0.3 m / min using a tensile tester. Peel force was measured on two identical specimens and then the average value was employed.

3. Measurement of high speed peeling force

The 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 with a roller of 2 Kg according to JIS Z 0237. Thereafter, after storing for 24 hours at a temperature of 23 ℃ and 65% relative humidity, a specimen was prepared by cutting so as to have a length of 25 mm and a length of 250 mm. Thereafter, the test piece was fixed to the glass substrate, and the peel force was measured while peeling the adhesive sheet from the anti-glare layer in the horizontal direction using a tensile tester at a peel angle of 180 degrees and a peel rate of 30 m / min. Peel force was measured on two identical specimens and then the average value was employed.

4. Measurement of peeling electrification voltage (ESD)

Specimens were prepared which were the same as those used for the 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 a glass substrate, and the peeling electrification voltage was measured while peeling the adhesive sheet of the specimen at a peel angle of about 180 degrees and a peel rate of 40 m / min with a tensile tester.

5. Whether the stain occurs after removing the adhesive sheet

After peeling the adhesive sheet from the same specimen used in the measurement of the low-speed peeling force, it was observed whether or not staining caused by static electricity occurred on the surface of the adherend and evaluated according to the following criteria.

<Evaluation Criteria>

A: When no stain occurs on the surface of the adherend

B: When stains occur on the surface of the adherend

Preparation Example 1 Preparation of Acrylic Copolymer (A)

2-ethylhexyl acrylate (EHA), 4-hydroxybutyl acrylate (HBA), 2-hydroxyethyl acrylate (HEA) and polyethylene glycol monomethyl ether methacrylate (ethylene oxide addition moles) as monomer components: 9 mole) (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 monomer mixture of the above ratio, 0.17 parts by weight of 2-cyano-2-propyl benzodithioate, 0.05 parts by weight of azobisisobutyronitrile, ethyl acetate in a 1 L reactor equipped with a refrigeration device for nitrogen gas reflux and for easy temperature control. After inserting 100 parts by weight, the stopper was sealed and oxygen was removed through nitrogen bubbling for 30 minutes. Then, the reaction flask was immersed in an oil bath previously heated to 60 ° C. to start the reaction. Samples were taken periodically to determine the conversion rate and the reaction was terminated when the conversion rate reached 90% or more.

Preparation Examples 2 to 4

Living radical polymers were prepared in the same manner as in Preparation Example 1, except that the ratio of the monomer components was adjusted as in Table 1 below.

Production 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) (× 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-hydroxybutyl butyl
HEA: 2-hydroxyethyl acrylate
DMAEA: dimethylaminoethyl acrylate
PEGMA: polyethyleneglycol monomethyl ether methacrylate (the number of ethylene oxide addition moles: 9 mol)

Preparation Example 5.

N-butyl acrylate (BA), 4-hydroxybutyl acrylate (HBA), 2-hydroxyethyl acrylate (HEA) in a 1 L reactor with nitrogen gas refluxed and a chiller installed to facilitate temperature control Was added in a weight ratio of 63: 2: 35, and 100 parts by weight of ethyl acetate was added to 100 parts by weight of monomer as a solvent. Subsequently, nitrogen gas was purged for 1 hour to remove oxygen, 0.1 part by weight of a reaction initiator (AIBN: azobisisobutyronitrile) was added thereto, and reacted for about 8 hours, after which the reaction mixture was diluted with ethyl acetate to form an acrylic adhesive resin (B1). Was prepared.

Preparation Example 6.

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

Production 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) (× 10000) 35 98 Molecular Weight Distribution (PDI) 6.2 8.2 EHA 2-ethylhexyl acrylate
BA: n-butyl acrylate
HBA: 4-hydroxybutyl butyl
HEA: 2-hydroxyethyl acrylate
DMAEA: dimethylaminoethyl acrylate
PEGMA: polyethyleneglycol monomethyl ether methacrylate (the number of ethylene oxide addition moles: 9 mol)

Examples 1-4 and Comparative Examples 1 and 2

Preparation of Pressure-Sensitive Adhesive Composition

The pressure-sensitive adhesive resin, crosslinking agent and antistatic agent of each preparation example were uniformly blended in the weight ratio as shown in Table 3 below, and the pressure-sensitive adhesive composition was prepared by diluting to an appropriate concentration in consideration of coating properties.

Preparation of Adhesive Sheet

The prepared pressure-sensitive adhesive composition was coated and dried on one surface of a poly (ethylene terephthalate) PET film (thickness: 38 μm) to form a uniform coating layer having a thickness of about 20 μm. Subsequently, the adhesive sheet was prepared by maintaining the coating layer at about 90 ° C. for 3 minutes to induce a crosslinking reaction.

Example Comparative example One 2 3 4 One 2 Acrylic adhesive resin A1 A2 A2 A3 B1 B2 Crosslinking agent 4.0 4.0 4.0 4.0 4.0 4.0 Antistatic A1 0.5 0.5 0.5 0.5 0.5 A2 0.5 Ratio unit: 100 parts by weight of acrylic adhesive resin
Crosslinking agent: MHG-80B, manufactured by Asahi
A1: lithium bistrifluoromethanesulfonylimide
A2: methyl tributylammonium bistrifluoromethanesulfonylimide

Physical properties measured for each of the pressure-sensitive adhesive sheet 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 Smear A A A A B B L: Low speed peeling force (unit: gf / inch)
H: High speed peeling force (unit: gf / inch)
H / L: Ratio of high speed peeling force (H) and low speed peeling force (L)
ESD: Peeling Voltage (Unit: kV)

Claims (12)

Including the acrylic adhesive resin whose molecular weight distribution is 5 or less,
The acrylic pressure-sensitive adhesive resin, the polymerization unit of the first monomer having a carbon number of 1 to 3 carbon atoms of the alkylene group represented by the formula (2) A and B in the formula (2); And a polymerized unit of a second monomer having a carbon number of 4 to 20 carbon atoms of the alkylene group represented by A and B of Chemical Formula 2, wherein the carbon number of the alkylene group is linear. Means the carbon number of the REN group),
Pressure-sensitive adhesive composition in which the ratio (a / b) of the weight (a) of the first monomer and the weight (b) of the second monomer is in the range of 1 to 20:
[Formula 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 of claim 1, wherein the acrylic pressure-sensitive adhesive resin is a living radical polymer (LRP). The pressure-sensitive adhesive composition of 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, comprising 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 of claim 1, wherein the acrylic pressure-sensitive adhesive resin is a random copolymer or a block copolymer. The pressure-sensitive adhesive composition of claim 1, wherein the pressure-sensitive adhesive further comprises a polymerized unit derived from a compound represented by the following general formula (1) or a nitrogen-containing reactive compound:
[Formula 1]

In Formula 1, Q is hydrogen or an alkyl group, U is an alkylene group, m is a number in the range of 0 to 20, and Z is hydrogen, an alkyl group or an aryl group. The pressure-sensitive adhesive composition of claim 1, further comprising a crosslinking agent. The pressure-sensitive adhesive composition of claim 7, wherein the crosslinking agent comprises at least one selected from the group consisting of aliphatic cyclic isocyanate compounds and aliphatic acyclic isocyanate compounds. Surface protective base layer; And an adhesive layer formed on one or both surfaces of the substrate layer and comprising the adhesive composition of claim 1 in a crosslinked state. The surface protection film of Claim 9 in which an adhesive layer contains the resin component whose molecular weight is 5,000 or less in the ratio of 5 weight% or less. The optical element of Claim 9 adhere | attached on the surface so that peeling is possible. A display device comprising the optical element of claim 11.