KR20090010294A - Antistatic pressure sensitive adhesive composition and polarizer including the same - Google Patents

Abstract

An antistatic adhesive composition and a polarizer including the same are provided to suppress the generation of electro static while enough maintaining the property of an adhesive and to prevent the exfoliation between an adhesive layer and a glass substrate and the foaming within the adhesive layer. An antistatic adhesive composition comprises (a) an acrylic copolymer 100.0 parts by weight which contains an acrylic acid ester monomer indicated as the chemical formula 1 and a unsaturated carboxylic acid monomer having one double bond and one or a plurality of carboxylic groups within molecule and has the average molecular weight (Mw) of 1,000,000~2,000,000; (b) a cross-linking agent 0.1~10 parts by weight; (c) an oligomer type silane coupling agent 0.01~2 parts by weight; and (d) lithiumbisimide 0.0001~0.001 parts by weight. In the chemical formula 1, R is hydrogen or methyl group; R2 is C1-10 alkyl group or alkoxy group-substituted or non-substituted C1-14 linear or branched alkyl group or aralkyl group.

Description

Antistatic pressure-sensitive adhesive composition, a polarizing plate comprising the same {Antistatic pressure sensitive adhesive composition and polarizer including the same}

The present invention relates to an antistatic pressure-sensitive adhesive composition and a polarizing plate including the same, and more particularly, to an antistatic pressure-sensitive adhesive composition excellent in antistatic performance, excellent adhesiveness under high temperature or high temperature and high humidity, and a polarizing plate including the same.

In general, in order to manufacture a liquid crystal display device, a liquid crystal cell and a polarizing plate containing a liquid crystal are basically required, and an appropriate adhesive layer or adhesive layer for bonding them should be used. The polarizing plate is stretched in a predetermined direction, and in order to protect both sides of PVA (Poly vinyl alcohol), which is a polarizing film (or polarizer) dyed with an iodine compound or a dichroic polarizing material, triacetyl cellulose (Triacetyl Cellulose, A TAC) protective film is laminated, and an antistatic layer, a reflective ring layer, a hard coating layer, etc. are laminated thereon, and a protective film made of a triacetyl cellulose film or a polymer of a cyclic olefin is formed on the opposite side, and the adhesive film is formed thereon. It is composed of a multilayer structure in which layers and release films are laminated.

On the other hand, when the polarizing plate on which the pressure-sensitive adhesive is laminated is bonded to the liquid crystal cell glass, when there is any problem, the polarizing plate on which the pressure-sensitive adhesive is laminated is applied again after peeling off the polarizing plate, but the pressure-sensitive adhesive is laminated on the polarizing plate from the liquid crystal cell glass. Even after peeling, what is excellent in what is called a rework property in which the residue of a adhesive, a cloudiness, etc. do not generate | occur | produce most on the surface of the glass substrate which was abutting the adhesive layer is calculated | required. Thereby, even if it peels the polarizing plate which an adhesive was laminated once from a glass substrate, since the surface of the glass substrate after peeling is maintained in a favorable state, it becomes possible to use as a glass substrate again.

In manufacturing a liquid crystal display, when the release film is peeled from the pressure-sensitive adhesive layer in the process of attaching the polarizing plate to the liquid crystal cell, static electricity is generated. The generated static electricity affects the alignment of the liquid crystal inside the liquid crystal display, thereby preventing defects. It causes the contamination by foreign matter between the liquid crystal cell and the adhesive by the electrostatic attraction.

In order to solve the problem caused by the static electricity, generally in forming an adhesive layer on the protective film, a method using a conductive adhesive with a conductive material added to the adhesive, an antistatic layer by applying a conductive material between the polarizing plate and the adhesive layer As the method for forming the polymer and the polymer added as the pressure-sensitive adhesive composition, a method using an ionic acrylate copolymer is used.

Among these, considering the fairness, it is most preferable to use a conductive adhesive, and a technique using an alkali metal salt as an antistatic agent which is excellent in conductivity and solves the problem of leakage to the surface is known.

In order to improve the compatibility of alkali metal salts, antistatic pressure-sensitive adhesives containing alkali metal salts have been reported to use polyether plasticizers or polymers containing ether groups. (KR20060018495A, KR20050072567A, JP2006111856A, JP2006111846A, JP2005206776A, JP11061085A, KR20060049137A)

An antistatic pressure-sensitive adhesive containing no polyether plasticizer and an alkali metal salt includes a technique for a composition containing 0.001 to 25 parts by weight of an anion and an alkali metal cation containing an acrylic polymer and a perfluoroalkyl group (KR20060127347A) and An antistatic adhesive composition containing an acrylic polymer having an acid value of 29 or less and 0.01 to 5% of fluorine-containing free lithium imide has been introduced (JP2005306937A).

However, the problem of the antistatic pressure-sensitive adhesive containing an alkali metal salt as described above has a problem that it is difficult to give the antistatic property while maintaining the physical properties of the pressure-sensitive adhesive by the addition of the alkali metal salt.

Therefore, in order to solve these problems in this field, the development of a new antistatic adhesive composition is required.

In order to solve the problems of the prior art as described above, the present invention can sufficiently suppress the generation of static electricity while sufficiently maintaining the physical properties of the pressure-sensitive adhesive, excellent adhesiveness under high temperature or high temperature and high humidity, the gap between the glass substrate and the pressure-sensitive adhesive layer It aims at providing the antistatic adhesive composition which can suppress peeling and foaming in an adhesive layer, and is excellent in the rework property at the time of peeling the polarizing plate matched with the glass substrate of a liquid crystal cell.

In order to achieve the above object, the present invention comprises a) i) an (meth) acrylic acid ester monomer represented by Formula 1 and ii) an unsaturated carboxylic acid monomer having one double bond and one or more carboxyl groups in the molecule, and 100 parts by weight of an acrylic copolymer having an average molecular weight (Mw) of 1,000,000 to 2,000,000; b) 0.1 to 10 parts by weight of crosslinking agent; c) 0.01 to 2 parts by weight of oligomeric silane coupling agent; And d) 0.001 to 0.0001 parts by weight of lithium bis (trifluoromethanesulfonyl) imide to provide an antistatic pressure-sensitive adhesive composition.

<Formula 1>

In Formula 1, R1 is hydrogen or methyl, and R2 is a C1-C14 linear or branched alkyl or aralkyl group which is unsubstituted or substituted with a C1-C10 alkyl group or an alkoxy group.

In another aspect, the present invention provides a polarizing plate comprising the antistatic pressure-sensitive adhesive composition as an adhesive layer on one side or both sides of the polarizing film.

The antistatic pressure sensitive adhesive composition of the present invention can sufficiently suppress static electricity generation while sufficiently maintaining the physical properties of the pressure sensitive adhesive, and has excellent adhesiveness under high temperature or high temperature and high humidity, and is caused by gaps or peeling between the glass substrate and the pressure sensitive adhesive layer, and in the pressure sensitive adhesive layer. The antistatic adhesive composition which can suppress foaming and is excellent in the rework property at the time of peeling the polarizing plate in which the adhesive was laminated | stacked on the liquid crystal cell glass substrate can be provided.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention have studied an antistatic pressure-sensitive adhesive composition having excellent antistatic properties, improved adhesion to glass under high temperature or high temperature and high humidity conditions, and excellent durability. And a pressure-sensitive adhesive composition containing an acrylic copolymer, a crosslinking agent, an oligomeric silane coupling agent, and lithium bis (trifluoromethanesulfonyl) imide containing an unsaturated carboxylic acid monomer having one or a plurality of carboxyl groups and a carboxyl group. It is possible to suppress the gaps, peeling, and foaming between the pressure-sensitive adhesive layer during adhesion, confirming that the durability and reworkability is excellent, and completed the present invention based on this.

The antistatic pressure-sensitive adhesive composition of the present invention comprises a) (a) a (meth) acrylic acid ester monomer represented by Formula 1 and ii) an unsaturated carboxylic acid monomer having one double bond and one or a plurality of carboxyl groups in a molecule, and having a weight average 100 parts by weight of an acrylic copolymer having a molecular weight (Mw) of 1,000,000 to 2,000,000, b) 0.1 to 10 parts by weight of a crosslinking agent, c) 0.01 to 2 parts by weight of an oligomeric silane coupling agent, and d) lithium bis (trifluoromethanesulfonyl) It is characterized by including an imide 0.001 ~ 0.0001 parts by weight.

The a) acrylic copolymer included in the antistatic adhesive composition of the present invention is iii) (meth) acrylic acid ester monomer represented by Formula 1 and ii) unsaturated carboxylic acid monomer having one double bond and one or a plurality of carboxyl groups in the molecule. It includes.

<Formula 1>

In Formula 1, R1 is hydrogen or methyl, and R2 is a C1-C14 linear or branched alkyl or aralkyl group which is unsubstituted or substituted with a C1-C10 alkyl group or an alkoxy group.

The iii) (meth) acrylic acid ester monomer preferably has an alkyl group or an aralkyl group having 1 to 14 carbon atoms in order to maintain a constant cohesive force at high temperature. If carbon number exceeds 14, the problem that the cohesion force of an adhesive becomes low will arise.

In addition, the iii) (meth) acrylic acid ester monomer may be substituted or unsubstituted with an alkyl group or an alkoxy group having 1 to 10 carbon atoms. If the carbon number exceeds 10, the glass transition temperature of the pressure-sensitive adhesive is increased, causing problems of deterioration of tackiness. Can be.

(Iii) The (meth) acrylic acid ester monomer is methyl acrylic acid (methyl acrylic acid), ethyl acrylate (ethyl acrylic acid), propyl acrylic acid (propyl acrylic acid), N-butyl acrylic acid (N-butyl acrylic acid), N-octyl acrylate (N-octyl acrylic acid), lauryl acrylic acid, isobutyl acrylic acid, 2-ethylhexyl acrylic acid, isooctyl acrylic acid, methacryl Propyl methacrylic acid, N-butyl methacrylic acid, N-octyl methacrylic acid, lauryl methacrylic acid, methacrylic acid Isobutyl methacrylic acid, 2-ethylhexyl methacrylic acid, isooctyl methacrylic acid, 2-methoxyehtyl acrylic acid, acrylic acid Ethoxyethyl acrylic acid, methacrylic acid 2- 1 or 2 selected from the group consisting of 2-methoxyethyl methacrylic acid, ethoxyethyl methacrylic acid, benzyl acrylic acid and benzyl acrylic acid The above can be mixed and used.

The said (i) (meth) acrylic acid ester monomer (non-volatile content) is contained 80-99.8 weight% in the said a) acrylic polymer (non-volatile content), Preferably it contains 90-99.8 weight%. When included in an amount of 80 to 99.8 wt%, the initial adhesion is excellent, the cohesion is kept constant, and there is an advantage of excellent durability.

Ii) The unsaturated carboxylic acid monomer having one double bond and one or more carboxyl groups in the molecule acts to impart cohesion or adhesive strength by chemical bonding so as not to cause cohesive breakage of the pressure-sensitive adhesive under high temperature or high temperature and high humidity conditions by reacting with a crosslinking agent. Do it.

Specific examples of the unsaturated carboxylic acid monomer having one double bond and at least one carboxyl group in the ii) molecule include acrylic acid, methacrylic acid, maleic acid and itaconic acid, and acrylic acid and methacrylic acid are preferable.

In addition, the monomer ii) may further include a monomer having a polar functional group in addition to the unsaturated carboxylic acid monomer having one double bond and one or more carboxyl groups in the molecule. Examples of the polar functional group include a hydroxyl group, an amide group, an epoxy group, an oxetanyl group, an amino group, an isocyanate group, an aldehyde group and the like.

Examples of the monomer in which the polar functional group is a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like.

Examples of the monomer in which the polar functional group is an amide include acrylamide, methacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide or N-metholacrylamide Etc. can be mentioned.

Examples of the monomer in which the polar functional group is an epoxy group include glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl acrylate or 3,4-epoxycyclohexylmethyl methacrylate. .

Examples of the monomer in which the polar functional group is an oxetanyl group include oxetanyl (meth) acrylate, 3-oxetanylmethyl (meth) acrylate, and (3-methyl-3-oxetanyl) methyl (meth) acrylate. Or (3-ethyl-3-oxetanyl) methyl (meth) acrylate.

Examples of the monomer in which the polar functional group is an amino group include N, N-dimethylaminoethyl acrylate or allyl amine.

2-methacryloyloxyethyl isocyanate etc. are mentioned as an example of the monomer in which the said polar functional group is an isocyanate group.

Examples of the monomer in which the polar functional group is an aldehyde group include acrylaldehyde and the like.

It is preferable that the said ii) carboxylic acid monomer (non-volatile content) is contained in 0.2 to 10 weight% with respect to the said acrylic polymer (non-volatile content). When included in an amount of 0.2 to 10% by weight, the adhesion between the glass substrate and the pressure-sensitive adhesive layer when the adhesive is adhered to the glass substrate is suppressed.

The a) acrylic polymer may further include one or two or more selected from a heterocyclic monomer, an alicyclic monomer and a vinyl monomer in an amount of 0 to 10% by weight based on the acrylic polymer (nonvolatile content).

The molecular weight of the a) acrylic polymer is preferably 1,000,000 to 2,000,000 in terms of weight average molecular weight (Mw) in terms of standard polystyrene by GPC. When the weight average molecular weight (Mw) is 1,000,000 to 2,000,000, the adhesiveness is excellent under high temperature and high humidity, and it is possible to suppress the gap and peeling between the glass substrate and the pressure-sensitive adhesive layer, thereby improving reworkability.

The a) acrylic polymer may further include other acrylic polymer.

The method of preparing the a) acrylic polymer may be prepared using a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, or a suspension polymerization method, and it is particularly preferable to prepare a solution polymerization method.

B) the crosslinking agent included in the antistatic adhesive composition of the present invention reacts with a carboxyl group, a hydroxyl group, an amide group, an epoxy group, an oxetanyl group, an amino group, an isocyanate group, an aldehyde group, and the like to enhance the cohesive force of the adhesive. The b) crosslinking agent may be used by mixing one or two or more selected from the group consisting of melamine derivatives, polyisocyanate compounds and polyepoxy compounds.

Specific examples of the melamine derivatives include hexamethyrolmelamine, hexamethoxymethylmelamine or hexabutoxymethylmelamine, and the like.

Specific examples of the polyisocyanate compound include diisocyanate compounds such as tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, 2,4- or 4,4-diphenylmethane diisocyanate, and trimethyrol propane of diisocyanate. And adducts to polyhydric alcohol compounds.

Specific examples of the polyepoxy compound include an epoxy compound of bisphenol A and an epichlorohydrin condensate type, polyglycidyl ether of a polyoxyalkylene polyol, glycerin diglycidyl ether, triglycidyl ether, and tetraglycidyl xylenediamine Etc. can be mentioned. It is preferable to use a polyisocyanate compound or a polyepoxy compound.

The b) crosslinking agent (non-volatile content) is preferably used in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the a) acrylic polymer (non-volatile content), more preferably 0.2 to 2 parts by weight. When included in an amount of 0.1 to 10 parts by weight, the pressure of the pressure-sensitive adhesive is excellent, there is no problem in adhesion durability such as bubbles or peeling, there is no lifting phenomenon does not occur there is an excellent durability reliability. If less than 0.1 part by weight, the internal stress is small and the adhesive strength is increased, it is difficult to secure durability, it is difficult to secure re-peelability and cutability. When it exceeds 10 parts by weight, the adhesive force is small, there is a problem that difficult to secure durability.

The adhesive composition of this invention contains c) oligomer type silane coupling agent. The main chain of the oligomeric silane coupling agent is fixed by entanglement with the polymer or fixed to the polymer by a functional group such as an epoxy group, an amine group or the like located on a branch connected to the main chain, and the alkoxysilane portion is strongly bound to the glass substrate of the liquid crystal cell, It serves to connect the pressure-sensitive adhesive and the liquid crystal cell. This improves the adhesion stability and further improves the heat and moisture resistance properties, and especially helps to improve the adhesion reliability when left for a long time under high temperature and high humidity. In addition, the most notable characteristic of the oligomeric silane coupling agent is that the migration from the inside of the pressure-sensitive adhesive to the surface is small, thereby suppressing the change of adhesion with the glass substrate over time, and has the advantage of easy durability.

C) The oligomeric silane coupling agent is an oligomeric silane in which at least one of tetramethoxysilane, tetraethoxysilane or tetrapropoxysilane and one or more alkoxysilanes having an epoxy group, an amine group or a thiol group are formed by copolymerization. It can be used 1 type or in mixture of 2 or more types selected from the group which consists of coupling agents.

The c) oligomeric silane coupling agent (nonvolatile content) is preferably used in an amount of 0.01 to 2 parts by weight based on 100 parts by weight of the a) acrylic copolymer (nonvolatile content). More preferably, it is 0.05-1 weight part.

When the silane coupling agent is included in an amount of 0.01 to 2 parts by weight, there is an advantage in that the adhesion stability and the adhesion reliability are improved under high temperature and high humidity. If it is less than 0.01 weight part, there exists a problem that the adhesive force with a cell is weak, and when it exceeds 2 weight part, there exists a problem that a rework property is bad.

D) Lithium bis (trifluoromethanesulfonyl) imide contained in the antistatic adhesive composition of the present invention imparts ionic conductivity to the adhesive, forms a stable structure, and functions to improve antistatic performance. The lithium bis (trifluoromethanesulfonyl) imide has excellent compatibility with the adhesive due to low coordination to metal cations and high hydrogenity due to the resonance structure of the anion and the high electronegativity of fluorine atoms. Optically transparent under moist heat conditions.

The d) lithium bis (trifluoromethanesulfonyl) imide is preferably included in an amount of 0.001 to 0.0001 parts by weight based on the solid content of the a) acrylic copolymer. When included at 0.001 to 0.0001 parts by weight, the cohesive force is kept constant, thereby improving durability and improving the antistatic property. When included in less than 0.0001 parts by weight, the physical properties of the pressure-sensitive adhesive is easy to reproduce, but it is difficult to secure sufficient antistatic performance. If it is contained in an amount exceeding 0.001 parts by weight, it is difficult to secure the physical properties of the pressure-sensitive adhesive such as gel fraction, adhesive strength, durability.

The antistatic adhesive composition of this invention can mix | blend well-known various additives in the range which does not reduce the function made into the objective of this invention, such as antistatic property, durability, re-peelability, and adhesive characteristics.

Examples of the additives include tackifying resins, plasticizers, ultraviolet light inhibitors, mold inhibitors, antifoaming agents and the like.

The tackifying resin acts to adjust the adhesive performance of the acrylic pressure-sensitive adhesive, rosin, rosin derivative or its hydrogenated body, polyterpene resin, terpene phenol resin, xylene resin, styrene resin, coumarone-indene resin, C5 petroleum Resin or C9 petroleum resin etc. can be used individually or in mixture of 2 or more types.

Examples of the plasticizer include carboxylic acid esters or chlorinated paraffins represented by phthalic acid esters.

Examples of the ultraviolet inhibitor include benzophenone ultraviolet ray inhibitors.

Examples of the antifungal agent include copper oxide or phenolic compounds.

Examples of the antifoaming agent include alcohols and silicone compounds.

The adhesive composition of this invention can be apply | coated directly to a base material or by a transfer method using a normal coating apparatus. In the case of direct coating, triacetyl cellulose or cyclic olefin polymer as a protective film of the polarizing plate can be used as a base material, and as a base material which can be used when applying by transfer method, polyethylene, polypropylene, polyethylene terephthalate, soft polyvinyl chloride Silicone or fluorinated release film can be used for various plastic films, resin plates, etc., but it is preferable to use a silicon release-treated substrate on polyethylene terephthalate.

After coating and drying, if necessary curing (approximately 14 days), the curing is completely cured by the crosslinking reaction between the crosslinking agent and the polymer, thereby exhibiting sufficient adhesion characteristics. Curing conditions, for example, usually proceed for 10 to 20 days at room temperature and 3 to 6 days at 40 to 50 ° C, and can be cured under more severe temperature conditions to shorten the curing time.

The present invention also provides a polarizing plate including the pressure-sensitive adhesive composition as an adhesive layer and a liquid crystal display including the polarizing plate.

The polarizing plate is formed by laminating a protective film on one side or both sides of a polarizing film (polarizer). The protective film and polarizer (polarizing film) which comprise a polarizing plate are not specifically limited.

Preferably, examples of the polarizing film include a film obtained by incorporating a polarizing component such as iodine or a dichroic dye into a film made of polyvinyl alcohol-based resin, and stretching the film. It is not limited, and can form a conventional thickness. At this time, the polyvinyl alcohol-based resin may be used polyvinyl alcohol, polyvinyl formal, polyvinyl acetal and ethylene, saponified vinyl acetate copolymer.

One side or both sides of the polarizing film has a cellulose-based film such as triacetyl cellulose, a polycarbonate film, a polyester-based film such as polyethylene terephthalate, a polyether sulfone-based film, polyethylene, polypropylene, cyclo-based or norbornene structure The multilayer film etc. which laminated | stacked protective films, such as a polyolefin type film and polyolefin type films, such as an ethylene-propylene copolymer, can be formed. At this time, the thickness of these protective films is also not particularly limited, and may form a conventional thickness.

In the present invention, the method of forming the pressure-sensitive adhesive layer on the polarizing plate is not particularly limited, and a method of applying and drying the pressure-sensitive adhesive using a bar coater or the like directly on the surface of the polarizing plate, or applying the pressure-sensitive adhesive to the surface of the peelable substrate once and drying The method of transferring the adhesive layer formed on the surface of this peelable base material to the surface of a polarizing plate, and then aging can be applied.

In addition, the polarizing plate of the present invention may be laminated with one or more layers that provide additional functions such as a protective layer, a reflective layer, an antiglare layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancement film.

The polarizing plate to which the pressure-sensitive adhesive of the present invention is applied can be applied to all conventional liquid crystal display devices, and the kind of the liquid crystal panel is not particularly limited. Preferably, the present invention may comprise a liquid crystal display device including a liquid crystal panel obtained by bonding the pressure-sensitive adhesive polarizing plate to one side or both sides of a liquid crystal cell.

The pressure-sensitive adhesive composition of the present invention can be suitably used not only as a pressure-sensitive adhesive for polarizing plates, but also as a pressure-sensitive adhesive for electrical or electronic component processing tapes such as carrier tapes, surface protection tapes such as stainless steel sheets, plastic plates, sheets, mats, adhesive labels, stickers, tapes, and the like. Can be.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

Polymerization example  1: Preparation of Acrylic Copolymer A-1

A 4-neck jacketed reactor (1L) was equipped with a stirrer, a thermometer, a reflux condenser, a dropping lot, and a nitrogen gas inlet tube, 164 parts by weight of ethyl acetate, 136 parts by weight of n-butylacrylic acid, and 0.6 parts by weight of acrylic acid. 0.7 weight part of, # 2-hydroxyethylacrylic acids were thrown in, and the reactor external temperature was heated up at 50 degreeC. A solution in which 0.14 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) was completely dissolved was added dropwise to 10 parts by weight of ethyl acetate as a reaction initiator. After the reaction was continued for 5 hours while maintaining the jacket outside temperature at 50 ° C, 90 parts of ethyl acetate was slowly added dropwise using a dropping lot for 1 hour. In addition, after 6 hours of additional stirring at the same temperature, 304 parts of ethyl acetate was added and stirred for 2 hours. Then, the solid content concentration is 20% by weight, represented by the formula (1), R 1 is hydrogen, R 2 is a linear alkyl having 4 carbon atoms and unsaturated (meth) acrylic acid monomer having one double bond and one or more carboxyl groups in the molecule The acrylic copolymer A-1 containing the carboxylic acid monomer and having a weight average molecular weight (polystyrene 'conversion) of 1,350,000 by GPC method was obtained.

Polymerization example  2: Preparation of Acrylic Copolymer A-2

The reaction was carried out in the same manner as in Polymerization Example 1, except that 0.35 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) was completely added dropwise to 10 parts by weight of ethyl acetate as a reaction initiator, and the solid content concentration was 20% by weight, An acrylic copolymer A-2 having a weight average molecular weight (polystyrene-like) 960,000 by GPC method was obtained.

Example  1 to 5 and Comparative example  1 to 12: Preparation of Antistatic Adhesive Composition

Mixing was carried out in the composition ratios (in terms of non-volatile content) shown in Table 1 and stirred for 10 minutes to prepare a uniform mixed solution. This was dried on two PET films (25 cm × 20 cm) coated with a release agent using an applicator, and then coated to have a thickness of 25 μm, respectively, and 100 ° C. The oven was dried in a forced hot air dryer for 3 minutes.

Table 1

Acrylic polymer (parts by weight) Crosslinking agent (parts by weight) Silane coupling agent (parts by weight) Metal salt (parts by weight) Example 1 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.0001 Example 2 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.0003 Example 3 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.0005 Example 4 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.0008 Example 5 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.001 Comparative Example 1 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0 Comparative Example 2 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.00005 Comparative Example 3 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.005 Comparative Example 4 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.01 Comparative Example 5 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.05 Comparative Example 6 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.1 Comparative Example 7 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.5 Comparative Example 8 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 One Comparative Example 9 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 2 Comparative Example 10 A-1 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 5 Comparative Example 11 A-2 100 B-1 / B-2 0.2 / 1 C-1 0.1 D-1 0.0005 Comparative Example 12 A-1 100 B-1 / B-2 0.2 / 1 C-2 0.1 D-1 0.0005

A-1: Acrylic Polymer Prepared by Synthesis Example

A-2: Acrylic Polymer Prepared by Synthesis Example

B-1: N, N, N ', N'-tetraglycidyl xylenediamine (trade name: TETRAD-X, manufacturer: X, Mitsubishi Chemical Company)

B-2: coronate-L (manufacturer: Japan Polyurethane Industry Co., Ltd.)

C-1: copolymer of 3-mercaptopropyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane (brand name: X-41-1818M, manufacturer: Shin-Etsu Corp. make)

C-2: 3-glycidoxy propyl trimethoxysilane (brand name: KBM-403, manufacturer: Shin-Etsu Corporation make)

D-1: lithium bis (trifluoromethanesulfonyl) imide (trade name: HQ-115, manufacturer: 3M)

Test Example : Performance Test of Antistatic Adhesive Composition

One PET film was laminated by laminating another release film on an adhesive layer made of the antistatic adhesive compositions of Examples 1 to 5 and Comparative Examples 1 to 12 to form a non-carrier film (NCF). The pressure-sensitive adhesive layer was obtained and stored in a thermo-hygrostat (60%, 25 ° C.) for gel fraction analysis, and another PET film was adhered to the polarizing plate as in the following plywood process, and the adhesion, durability and reworkability were evaluated.

(Plywood process)

The pressure-sensitive adhesive layer prepared above was adhesively processed on an iodine-based polarizing plate having a thickness of 185 μm, and stored in a thermo-hygrostat (60%, 25 ° C.). The obtained polarizing plate was cut | disconnected to the appropriate magnitude | size, and used for evaluation.

Evaluation test

Durability Reliability Evaluation

The polarizing plate (250 mm x 200 mm) coated with the adhesive prepared in Examples 1 to 5 and Comparative Examples 1 to 12 was cut into a size of a glass substrate (200 mm x 200 mm x 0.7 mm) and attached to the glass substrate. At this time, the pressure was about 5kg / ㎠ to clean the room so that no bubbles or foreign matter.

Moisture and heat resistance: In order to determine the heat and humidity characteristics of these specimens, the specimens were left for 500 hours at 60 ° C. and 90% relative humidity, and then observed for bubble or peeling.

Heat resistance: The heat resistance was observed at 80 ℃ for 500 hours after the bubble or peeling. Immediately after evaluating the state of the specimen was performed at room temperature for 24 hours. The evaluation criteria for reliability are as follows.

○: no bubbles or peeling

△: bubble or peeling phenomenon

×: Bubbles or peeling phenomenon

Surface resistance measurement method

The surface resistance of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive prepared in Examples 1 to 5 and Comparative Examples 1 to 12 was measured using the plywood process. The surface resistance was observed under a voltage of 500 V at a temperature of 23 ° C. and a relative humidity of 60%. Surface resistances above 10 ¹⁴ are generally considered to be antistatic.

Measuring instrument: Surface resistance measuring instrument (MCP-HT450 / MITSUBISHI CHEMICAL), probe bar (URS, UR100), probe bar measuring instrument (URS, for UR 100)

-Measuring method: Measure the three places of the surface 10 times and take the average value.

<Evaluation of reworkability>

The pressure-sensitive adhesive coated polarizing plate (250mm × 200mm) prepared in Examples 1 to 5 and Comparative Examples 1 to 12 was cut into a size of a glass substrate (200mm × 200mm × 0.7mm), attached to a glass substrate, and the temperature was 50 ° C., The autoclave process was performed for 20 minutes by the pressure of 5 kg / cm <2> (490.3 kPA). Subsequently, after 48 hours of storage in an oven at 50 ° C, the polarizing plate was peeled from the pressure-sensitive adhesive test piece in a 180 ° direction at a rate of 300 mm / min in an atmosphere of a temperature of 23 ° C and a relative humidity of 50%, and the surface of the glass substrate after peeling. Observed. The results were classified according to the following criteria, and shown in Table 2 as well.

(Circle): The surface blur of a glass plate is not observed.

(Triangle | delta): The surface blur of a glass plate is observed.

X: The peeling residue of an adhesive is observed on the glass plate surface.

 Table 2

Durability (Heat Resistant / Heat Resistant) Surface resistivity (Ω / □) Reworkability Example 1 ○ / ○ 4 × 10 ¹³ ○ Example 2 ○ / ○ 1 × 10 ¹³ ○ Example 3 ○ / ○ 9 × 10 ¹² ○ Example 4 ○ / ○ 8 × 10 ¹² ○ Example 5 ○ / ○ 8 × 10 ¹² ○ Comparative Example 1 ○ / ○ > 10 ¹⁴ ○ Comparative Example 2 ○ / ○ > 10 ¹⁴ ○ Comparative Example 3 △ / ○ 4 × 10 ¹² ○ Comparative Example 4 △ / ○ 7 × 10 ¹¹ ○ Comparative Example 5 △ / ○ 4 × 10 ¹¹ ○ Comparative Example 6 △ / ○ 3 × 10 ¹¹ ○ Comparative Example 7 × / △ 2 × 10 ¹¹ ○ Comparative Example 8 × / △ 1 × 10 ¹¹ ○ Comparative Example 9 × / △ 4 × 10 ¹⁰ ○ Comparative Example 10 × / × 3 × 10 ⁹ ○ Comparative Example 11 × / △ 7 × 10 ¹² △ Comparative Example 12 ○ / ○ 9 × 10 ¹² ×

According to the results of Table 2, the antistatic pressure-sensitive adhesive compositions of Examples 1 to 5 have sufficient antistatic ability required when the polarizing plate is bonded by addition of 0.001 to 0.0001 parts by weight of lithium bis (trifluoromethanesulfonyl) imide. While exhibiting, favorable values are maintained in durability and reworkability. However, as in Comparative Example 1-2, when lithium bis (trifluoromethanesulfonyl) imide is less than 0.0001, it does not show sufficient antistatic property, on the contrary, as in Comparative Example 3-10, lithium bis (trifluoro When romethanesulfonyl) imide is more than 0.001, antistatic property is excellent, but durability has not been secured. In Comparative Example 11, in which the polymer had a molecular weight of 1.4 million or less, durability was not secured, and there was a problem in reworkability as well. Moreover, in the case of the comparative example 12 using the silane coupling agent of a monomolecular form, there existed a problem in reworkability.

Claims (5)

a) i) a (meth) acrylic acid ester monomer represented by Formula 1 and ii) an unsaturated carboxylic acid monomer having one double bond and one or a plurality of carboxyl groups in the molecule, wherein the weight average molecular weight (Mw) is 1,000,000 to 2,000,000 100 parts by weight of acrylic copolymer; b) 0.1 to 10 parts by weight of crosslinking agent; c) 0.01 to 2 parts by weight of oligomeric silane coupling agent; And d) antistatic pressure-sensitive adhesive composition comprising a lithium bis (trifluoromethanesulfonyl) imide 0.0001 ~ 0.001 parts by weight: <Formula 1>

In Formula 1, R1 is hydrogen or methyl, and R2 is a C1-C14 linear or branched alkyl or aralkyl group which is unsubstituted or substituted with a C1-C10 alkyl group or an alkoxy group. The method according to claim 1, (Iii) The (meth) acrylic acid ester monomer is methyl acrylic acid (methyl acrylic acid), ethyl acrylate (ethyl acrylic acid), propyl acrylic acid (propyl acrylic acid), N-butyl acrylic acid (N-butyl acrylic acid), N-octyl acrylate (N-octyl acrylic acid), lauryl acrylic acid, isobutyl acrylic acid, 2-ethylhexyl acrylic acid, isooctyl acrylic acid, methacryl Propyl methacrylic acid, N-butyl methacrylic acid, N-octyl methacrylic acid, lauryl methacrylic acid, methacrylic acid Isobutyl methacrylic acid, 2-ethylhexyl methacrylic acid, isooctyl methacrylic acid, 2-methoxyehtyl acrylic acid, acrylic acid Ethoxyethyl acrylic acid, methacrylic acid 2-meth 1 or 2 selected from the group consisting of 2-methoxyethyl methacrylic acid, ethoxyethyl methacrylic acid, benzyl acrylic acid and benzyl acrylic acid An antistatic adhesive composition characterized by the above. The method according to claim 1, C) The oligomeric silane coupling agent is an oligomer type in which at least one of tetramethoxysilane, tetraethoxysilane or tetrapropoxysilane and at least one of alkoxy silanes having an epoxy group, an amine group or a thiol group are formed by copolymerization. It is a silane coupling agent, The antistatic adhesive composition characterized by the above-mentioned. The method according to claim 1, Said ii) unsaturated carboxylic acid monomer having one double bond and one or a plurality of carboxyl groups in the molecule is selected from the group consisting of acrylic acid, methacrylic acid, maleic acid and itaconic acid. A polarizing plate comprising the antistatic pressure sensitive adhesive composition of claim 1 as an adhesive layer on one or both surfaces of the polarizing film.