KR101510470B1 - Adhesive composition, product using the same, and display using the product - Google Patents

Abstract

The present invention provides a pressure-sensitive adhesive composition which is excellent in coatability, transparency, adhesiveness (particularly, low-temperature adhesion property), excellent foam resistance and peelability, and excellent in internal performance.

The pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition comprising an acrylic polymer having a weight average molecular weight of 400,000 to 1,600,000 which is composed of an alkoxyalkyl acrylate (component A) and an acrylic monomer having a crosslinkable functional group (component B) , Wherein the content of the component A is 45 to 99.5 parts by weight and the content of the component B is 0.5 to 4.5 parts by weight based on 100 parts by weight of the total monomer component constituting the acrylic polymer and the amount of the carboxyl group- As shown in FIG.

A pressure-sensitive adhesive composition, an alkoxyalkyl acrylate, an acrylic monomer

Description

TECHNICAL FIELD [0001] The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive product using the pressure-

The present invention relates to an acrylic pressure sensitive adhesive composition. More specifically, the present invention relates to a pressure-sensitive adhesive which is excellent in adhesion to a transparent plastic such as glass and acrylic, polycarbonate, and polyethylene terephthalate (PET), excellent foam resistance and peelability, transparency and coating property, ≪ / RTI > Further, the present invention relates to a pressure-sensitive adhesive product coated with the pressure-sensitive adhesive composition, and a display to which the pressure-sensitive adhesive product is bonded.

Recently, FPD (Flat Panel Display) including a liquid crystal display (LCD) has been widely used. The FPD is manufactured by laminating an optical film having various functions via a pressure-sensitive adhesive (pressure-sensitive adhesive). In these applications, the pressure-sensitive adhesive is required to have excellent reliability such as adhesiveness and transparency as well as properties such as foaming and peeling in a high-temperature or high-humidity environment (foaming and releasability).

Conventionally, as a method for improving the foaming and peeling property under a high temperature and high humidity environment, a method in which a homopolymer is copolymerized with a monomer containing a functional group such as a monomer (high Tg monomer) or a carboxyl group exhibiting a high glass transition temperature (Tg) (Low molecular weight polymer) is added to the pressure-sensitive adhesive to increase the Tg of the pressure-sensitive adhesive.

For example, there has been known a pressure-sensitive adhesive composition which is excellent in adhesiveness to plastics at room temperature and high temperature and foam resistance, including an oligomer containing a polymer containing a carboxyl group-containing monomer as a constituent component and an amino group-containing monomer as a constituent component Patent Document 1). (Meth) acrylic acid ester polymer (A) having a weight average molecular weight of 500,000 to 2,500,000 and (meth) acrylic acid ester polymer (B) having a weight average molecular weight of 5,000 to 500,000, B) has a nitrogen-containing functional group (see Patent Document 2). Further, 100 parts by weight of a pressure-sensitive adhesive polymer obtained by copolymerizing a carboxyl group-containing monomer with a (meth) acrylic acid alkoxyalkyl ester as a main component and 100 parts by weight of an alkyl methacrylate ester, a methacrylic acid cycloalkyl ester, 5 to 40 parts by weight of a low molecular weight polymer obtained by copolymerizing an amino group or an amide group-containing monomer as a main component, and 0.001 to 2.0 parts by weight of a crosslinking agent, and a pressure-sensitive adhesive sheet using the pressure- (See Patent Document 3).

However, these pressure-sensitive adhesive compositions have a problem that their adhesive properties under low-temperature or high-speed conditions deteriorate as the Tg of the pressure-sensitive adhesive increases. In addition, the pressure-sensitive adhesive composition containing a carboxyl group-containing monomer has a problem that the internal performance is poor when it is adhered to a metal thin film (including a metal oxide thin film). That is, it is a reality that an excellent pressure-sensitive adhesive composition in which all the properties such as anti-foaming and peeling properties under a high-temperature and high-humidity environment, adhesive properties in a low-temperature region,

[Patent Document 1] Japanese Patent No. 3516035 Specification

[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2001-89731

[Patent Document 3] Japanese Unexamined Patent Publication No. 2002-327160

An object of the present invention is to provide a pressure-sensitive adhesive composition which is excellent in coatability, adhesiveness, transparency, anti-foaming and releasability, and excellent in internal performance. The present invention also provides a highly reliable adhesive product and display using the same.

In some applications, there is a strict requirement for suppressing the yellowing of the pressure-sensitive adhesive. For example, in the case of using an aromatic isocyanate compound as a crosslinking agent, yellowing is a problem and a countermeasure is sometimes required. As a method for suppressing the yellowing, it is effective to use an aliphatic isocyanate crosslinking agent. However, in this case, it has been found that the crosslinking speed is abnormally slowed, and there is a problem in productivity. In a general adhesive sheet, it is possible to accelerate the crosslinking reaction by warming. However, since there is a strict appearance requirement in display applications, it is difficult to use a crosslinking promoting method by heating which is easy to generate and promote scratching.

Accordingly, another object of the present invention is to provide a pressure-sensitive adhesive composition which is further excellent in yellowing resistance and productivity and a pressure-sensitive adhesive product and display using the same.

The present inventors have made intensive investigations in order to achieve the above object and as a result have found that an acrylic polymer having a specific molecular weight having an alkoxyalkyl acrylate as a main monomer can take a crosslinked structure, A pressure-sensitive adhesive composition that satisfies the foamability and peelability of the undercoat layer can be obtained. Thus, the present invention has been completed.

In addition, by using an amine compound containing a specific amount of an aliphatic isocyanate crosslinking agent and a plurality of hydroxyl groups, it is possible to obtain a pressure-sensitive adhesive composition excellent in productivity even when yellowing is suppressed and crosslinking is not promoted by heating Respectively.

That is, the present invention relates to a pressure-sensitive adhesive composition comprising an acrylic polymer having a weight average molecular weight of 400,000 to 1,600,000, which is composed of an alkoxyalkyl acrylate (component A) and an acrylic monomer (component B) having a crosslinkable functional group as essential monomer components and a crosslinking agent , Wherein the content of the component A is 45 to 99.5 parts by weight and the content of the component B is 0.5 to 4.5 parts by weight based on 100 parts by weight of the total monomer components constituting the acrylic polymer and the content of the carboxyl group- The present invention provides a pressure-sensitive adhesive composition comprising the pressure-sensitive adhesive composition of the present invention.

Further, the present invention relates to an acrylic polymer composition comprising 100 parts by weight of an acrylic polymer having an average molecular weight of 400,000 to 1,600,000 which is composed of an alkoxyalkyl acrylate (component A) and an acrylic monomer having a crosslinkable functional group (component B) as essential monomer components, 0.01 to 3.0 parts by weight of an aliphatic isocyanate crosslinking agent and 0.01 to 5.0 parts by weight of an amine-based compound containing a plurality of hydroxyl groups, wherein the component (A) relative to 100 parts by weight of the total monomer component constituting the acrylic polymer A content of 45 to 99.5 parts by weight, a content of component B of 0.5 to 4.5 parts by weight, and substantially no carboxyl group-containing monomer in the monomer component constituting the acrylic polymer.

Further, the present invention provides the above pressure-sensitive adhesive composition, wherein component B is an acrylic monomer having a hydroxyl group.

Further, the present invention provides the above pressure-sensitive adhesive composition wherein the gel fraction after cross-linking structuring is 40 to 80%.

The present invention also provides a pressure-sensitive adhesive product coated with the pressure-sensitive adhesive composition.

Further, the present invention provides a display using the adhesive product.

According to the pressure-sensitive adhesive composition of the present invention, since it has the above-described constitution, it is excellent in coatability, adhesiveness (particularly low temperature bonding property), transparency and anti-foamability and peelability, , Optical properties such as visibility of these products can be improved. Further, since the metal thin film (including the metal oxide thin film) is not corroded, it can be used also for a portion for laminating a film formed with a metal thin film such as an ITO (indium tin oxide) film.

Furthermore, by using an amine compound containing a specific amount of an aliphatic isocyanate crosslinking agent and a plurality of hydroxyl groups, the productivity is improved even when the inner wall is not denatured and the temperature is not elevated. Therefore, .

[Pressure sensitive adhesive composition]

The pressure-sensitive adhesive composition of the present invention comprises an acrylic polymer and a crosslinking agent as essential components.

The acrylic polymer used in the pressure-sensitive adhesive composition of the present invention is a polymer composed of an acrylic acid alkoxyalkyl ester (alkoxyalkyl acrylate) (hereinafter occasionally referred to as "component A") as a monomer main component. In addition to the monomer main component, an acrylic monomer having a crosslinkable functional group (excluding a carboxyl group) (hereinafter sometimes referred to as "component B") is included as an essential copolymerizable monomer component. If desired, another monomer component may be used. On the other hand, the monomer containing a carboxyl group is substantially not contained as a monomer component.

Examples of the alkoxyalkyl acrylate (component A) include, but are not limited to, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, methoxytriethylene glycol acrylate, 3-methoxypropyl acrylate, Methoxybutyl acrylate, 4-ethoxybutyl acrylate, and the like. The component A may be used alone or in combination of two or more.

In the acrylic polymer, the monomer proportion of the component A as the main component of the monomer is 45 to 99.5 parts by weight, preferably 50 to 80 parts by weight, per 100 parts by weight of the total monomer component. When the content of the component A in the total monomer components is less than 45 parts by weight, the foaming and releasability becomes insufficient. On the other hand, if it exceeds 99.5 parts by weight, the content of the component B is lowered, the crosslinking structure in the polymer becomes insufficient, and the foaming and peeling property becomes insufficient. On the other hand, the above-mentioned monomer ratio refers to the ratio (mixing ratio) of the amount of each monomer component in the preparation of the acrylic polymer. Other monomer ratios and monomer contents are also the same.

The crosslinkable functional group in the acrylic monomer (component B) having a crosslinkable functional group is not particularly limited as long as it is a functional group other than a carboxyl group and is a functional group capable of crosslinking with a crosslinking agent which will be described later. Examples thereof include glycidyl groups, amino groups, An amide group, and a hydroxyl group. Specific examples of the component B include glycidyl (meth) acrylate, glycidylmethyl (meth) acrylate, and glycidylmethyl (meth) acrylate as a monomer having a glycidyl group; Examples of the monomer having an amino group include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate; N-methylol acrylamide as a monomer having an N-methylolamide group; (Meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate as the monomer having a hydroxyl group. . Among them, preferred is a monomer having an N-methylolamide group, an acrylic monomer having a hydroxyl group, more preferably an acrylic monomer having a hydroxyl group, particularly preferably 2-hydroxyethyl acrylate (2HEA) Hydroxybutyl acrylate (4HBA), 3-hydroxypropyl acrylate (3HPA), and 6-hydroxyhexyl acrylate (6HHA). On the other hand, "(meth) acryl" means "acrylic" and / or "methacryl". The same goes for the following.

In the acrylic polymer, the proportion of the monomer B is 0.5 to 4.5 parts by weight, preferably 0.5 to 3.0 parts by weight, more preferably 0.5 to 2.0 parts by weight based on 100 parts by weight of the total monomer component. When the content of the component B in the total monomer components is less than 0.5 parts by weight, the crosslinking structure into the polymer becomes insufficient and the foaming tends to occur. On the other hand, if it exceeds 4.5 parts by weight, the cross-linking structure becomes too dense to easily cause peeling.

The acrylic polymer does not substantially contain a monomer containing a carboxyl group as a monomer component. On the other hand, "substantially not included" means that the active compound is not compounded except when it is inevitably incorporated. Specifically, it is less than 0.05 part by weight based on 100 parts by weight of the total monomer component, preferably 0.01 part by weight By weight, more preferably less than 0.001 part by weight. When the carboxyl group-containing monomer is included, the corrosion resistance to the metal thin film is lowered (for example, the conductive performance of the ITO film is lowered). On the other hand, examples of the carboxyl group-containing monomer include acrylic acid (AA), methacrylic acid, itaconic acid, maleic acid, fumaric acid and crotonic acid. Incidentally, the acid anhydrides of these carboxyl group-containing monomers (for example, an acid anhydride group-containing monomer such as maleic anhydride and itaconic anhydride) are also included as the carboxyl group-containing monomers.

Examples of other monomer components other than the component A and the component B in the acrylic polymer include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 12 carbon atoms such as (meth) acrylic acid methyl, (meth) (Meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, isobutyl (meth) acrylate, isobutyl (meth) acrylate, sec- (Meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl ) Decyl acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, and dodecyl (meth) acrylate. In addition, methacrylic acid alkoxyalkyl esters such as methoxyethyl methacrylate and ethoxyethyl methacrylate; Polyfunctional monomers such as triethylene glycol diacrylate, ethylene glycol dimethacrylate and trimethylolpropane tri (meth) acrylate; Vinyl acetate, styrene, and cyclohexyl (meth) acrylate.

Among the above-mentioned other monomer components, a monomer having a Tg of 0 占 폚 or less as a homopolymer is preferred from the viewpoint of suppressing the glass transition temperature (Tg) of the acrylic polymer to a low level, more preferably a monomer having a Tg of -40 占 폚 or lower It is a monomer. For example, 2-ethylhexyl acrylate (2EHA) and butyl acrylate (BA) are preferred.

The acrylic polymer can be produced by a publicly known polymerization method. Examples of the polymerization method of the acrylic polymer include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method and a polymerization method by ultraviolet irradiation. From the viewpoints of transparency, water resistance and cost, Method is preferable, and particularly, a solution polymerization method is preferable.

The polymerization initiator used in the solution polymerization of the acrylic polymer is not particularly limited and may be appropriately selected from known and publicly available ones. For example, 2,2'-azobisisobutyronitrile, 2,2'-azo Bis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis Azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2,4,4-trimethylpentane), dimethyl-2,2'-azobis Azo-based polymerization initiators such as < RTI ID = 0.0 > Butyl peroxybenzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis (t- And peroxide-based polymerization initiators such as trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, and the like are preferably exemplified. The polymerization initiator may be used alone or in combination of two or more. The amount of the polymerization initiator to be used is not particularly limited and may be selected within a range of, for example, about 0.01 to 1 part by weight based on 100 parts by weight of the total monomer component.

On the other hand, various general solvents can be used in solution polymerization. Examples of such a solvent include esters such as ethyl acetate and n-butyl acetate; Aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; And organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. Solvents may be used alone or in combination of two or more.

The weight average molecular weight of the acrylic polymer (hereinafter sometimes simply referred to as molecular weight) is 400,000 or more and 1.6 million or less (400,000 to 1,600,000), preferably 60,000 to 1,200,000, and more preferably, Only. If the weight average molecular weight of the acrylic polymer is less than 400,000, the adhesive force and cohesive force required for the pressure-sensitive adhesive can not be obtained and the foamability and peeling property becomes insufficient. On the other hand, if the acrylic polymer exceeds 160,000, .

On the other hand, the weight average molecular weight (Mw) can be measured by a gel permeation chromatograph (GPC) method. More specifically, it can be determined by measurement under the following GPC measurement conditions with a polystyrene conversion value using a trade name "HLC-8120GPC" (manufactured by TOSOH CORPORATION) as a GPC measurement apparatus.

Measurement conditions of GPC

Sample concentration: 0.2 wt% (tetrahydrofuran solution)

Sample injection volume: 10 μl

Eluent: tetrahydrofuran (THF)

· Flow rate (flow rate): 0.6 mL / min

· Column temperature (measuring temperature): 40 ° C

Column: trade name "TSKgelSuperHM-H / H4000 / H3000 / H2000" (manufactured by Toso Kabushiki Kaisha)

Detector: Differential refractometer (RI)

The weight average molecular weight of the acrylic polymer can be adjusted by the monomer concentration, the monomer dropping rate, etc. in addition to the kind of the polymerization initiator, the amount of the polymerization initiator used, and the temperature and time during polymerization.

The glass transition temperature (Tg) of the acrylic polymer is preferably in the range of -40 to -40 DEG C in terms of improving the adhesion property at low temperature or the property at high speed (for example, the property (drop impact resistance) 70 deg. C is preferable, and more preferably -50 deg. C to -70 deg. On the other hand, Tg of the acrylic polymer is a glass transition temperature (theoretical value) expressed by the following equation.

1 / Tg = W ₁ / Tg ₁ + W ₂ / Tg ₂ + + W _n / Tg _n

In the above equation, Tg is the glass transition temperature (unit: K) of the acrylic polymer, Tg _n is the glass transition temperature (unit: K) of the homopolymer of monomer n, and W _n is the weight fraction of monomer n.

The storage modulus of the acrylic polymer at 80 캜 is preferably 0.01 MPa or more, and more preferably 0.03 MPa or more. On the other hand, the storage elastic modulus was measured at a frequency of 1 Hz using an "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific, and the pressure-sensitive adhesive layer was laminated to a thickness of about 1.5 mm. On the other hand, the measurement was carried out at a temperature raising rate of 5 deg. C / min in the range of -70 to 200 deg.

The crosslinking agent to be used in the pressure-sensitive adhesive composition of the present invention can be widely selected from among conventionally known ones, but may be suitably selected from a polyfunctional melamine compound, a polyfunctional epoxy compound, a polyfunctional isocyanate compound and the like by the functional group of the component B. The crosslinking agent may be used alone or in combination of two or more. In the present invention, by using a cross-linking agent, the cross-linking structure is formed to balance the foam-release properties.

Examples of the polyfunctional melamine compound include methylated trimethylol melamine, butylated hexamethylol melamine, and the like. Examples of the polyfunctional epoxy compound include diglycidyl aniline, glycerin diglycidyl ether, and the like. As the polyfunctional isocyanate compound, for example, a reaction of tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI), polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate, trimethylol propane and tolylene diisocyanate Products, polyether polyisocyanates, polyester polyisocyanates, and the like. Among them, it is preferable to use a monomer containing a hydroxyl group as the component B and use a polyfunctional isocyanate compound (isocyanate crosslinking agent) as a crosslinking agent.

Above all, it is preferable to use an aliphatic isocyanate crosslinking agent as a crosslinking agent, particularly from the viewpoint of improving yellowing resistance (yellowing inhibition). As the aliphatic isocyanate crosslinking agent, conventionally known ones can be widely used, and examples thereof include 1,6-hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate, 3- Methyl-1,5-pentane diisocyanate, lysine diisocyanate, isophorone diisocyanate, cyclohexyl diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethyl xylene Diisocyanate, and the like. Among them, hexamethylene diisocyanate (1,6-hexamethylene diisocyanate) (including a reaction product using HDI) is preferably used as the component B, a monomer containing a hydroxyl group and a crosslinking agent.

The amount of the crosslinking agent to be used is not particularly limited, but is usually 0.01 to 5 parts by weight, more preferably 0.01 to 3 parts by weight, further preferably 0.1 to 3 parts by weight, more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the acrylic polymer. Most preferably 0.1 to 1.0 part by weight.

In order to accelerate the crosslinking reaction, an amine compound containing a plurality of hydroxyl groups may be used in the pressure-sensitive adhesive composition of the present invention. The use of an aliphatic isocyanate crosslinking agent as the crosslinking agent is particularly preferably used in view of maintaining the productivity (particularly, the crosslinking reaction proceeds rapidly even if the crosslinking is not promoted by heating). The amine compound containing a plurality of hydroxyl groups is not particularly limited as long as it is an amine compound having two or more hydroxyl groups (alcoholic hydroxyl groups) in the molecule. In the amine compound, the number of nitrogen atoms contained in the molecule is not particularly limited. The amine compound containing a plurality of hydroxyl groups may be used alone or in combination of two or more.

Specific examples of the amine compound containing a plurality of hydroxyl groups include amine compounds having one nitrogen atom in the molecule, such as diethanolamine, dipropanolamine, diisopropanolamine, N-methyldiethanol Dialkylamines such as amine, N-methyldiisopropanolamine, N-ethyldiethanolamine, N-ethyldiisopropanolamine, N-butyldiethanolamine and N-butyldiisopropanolamine; And trialcohol amines such as triethanolamine, tripropanolamine and triisopropanolamine.

Examples of the amine compound having two nitrogen atoms in the molecule include amine compounds represented by the following formula (1).

Wherein R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom or [- (R ⁵ O) _m (R ⁶ O) _n -H]. Here, R ⁵ and R ⁶ are different and each represents an alkylene group. m and n are an integer of 0 or more and do not become 0 at the same time. Two or more of R ¹ , R ² , R ³ and R ⁴ are [- (R ⁵ O) _m (R ⁶ O) _n -H]. X represents a divalent hydrocarbon group, and p is an integer of 1 or more.

Examples of the alkylene group represented by R ⁵ and R ⁶ in the general formula (1) include alkylene groups having about 1 to 6 carbon atoms such as methylene, ethylene, propylene, trimethylene, tetramethylene, ethylethylene, pentamethylene, (Preferably an alkylene group having 1 to 4 carbon atoms, more preferably an alkylene group having 2 or 3 carbon atoms). The alkylene group may have either a straight chain or branched chain form. Among them, an ethylene group and a propylene group are preferably used as the alkylene group of R ⁵ and R ⁶ .

In addition, although m and n are not particularly limited as long as they are integers of 0 or more, for example, at least one of m and n may be selected from the range of 0 to 20, preferably 1 to 10. It is often the case that one of m and n is 0 and the other is an integer of 1 or more (especially 1). On the other hand, m and n are not 0 at the same time (when - (R ⁵ O) _m (R ⁶ O) _n -H] represents a hydrogen atom when m and n are both 0).

Further, X represents a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include an alkylene group, a cycloalkylene group, and an arylene group. The alkylene group of X may be either straight-chain or branched. It may be either saturated or unsaturated. Examples of the alkylene group represented by X include an alkylene group having about 1 to 6 carbon atoms (preferably an alkylene group having 1 to 4 carbon atoms, more preferably an alkylene group having 2 or 4 carbon atoms, such as methylene, ethylene, propylene, trimethylene, 3 < / RTI > alkylene group). Examples of the cycloalkylene group include a cycloalkylene group of about 5 to 12-membered rings such as a 1,2-cyclohexylene group, a 1,3-cyclohexylene group, and a 1,4-cyclohexylene group. . As the arylene group, for example, a 1,2-phenylene group, a 1,3-phenylene group and a 1,4-phenylene group can be used.

In addition, p is not particularly limited as long as it is an integer of 1 or more, and can be selected from the range of, for example, about 1 to 10, preferably 1 to 6, more preferably 1 to 4.

More specifically, examples of the amine compound represented by Formula 1 include N, N, N ', N'-tetrakis (2-hydroxyethyl) ethylenediamine, N, N, N, N ', N'-tetrakis (2-hydroxypropyl) ethylenediamine, N, -Hydroxypropyl) trimethylenediamine, polyoxyethylene condensates of alkylene diamines such as polyoxyethylene condensates of ethylene diamine, polyoxypropylene condensates of ethylene diamine, and polyoxyethylene-polyoxypropylene condensates of ethylene diamine, Condensates and the like. As such an amine compound, commercially available products such as "EDP-300", "EDP-450", "EDP-1100" and "Pluronic" (manufactured by ADEKA Corporation) may be used.

The amount of the amine compound containing a plurality of hydroxyl groups is preferably from 0.01 to 5.0 parts by weight, more preferably from 0.01 to 5.0 parts by weight, based on 100 parts by weight of the acrylic polymer, from the viewpoints of promoting the crosslinking reaction and improving the productivity Is 0.05 to 1.0 part by weight.

In order to accelerate the crosslinking reaction, a crosslinking accelerator other than those described above may be used in the pressure-sensitive adhesive composition of the present invention. Examples of such a crosslinking accelerator include amino compounds such as N, N, N ', N'-tetramethylhexanediamine and imidazole, amine compounds having a plurality of reactive functional groups other than hydroxyl groups, cobalt naphthenate, dibutyltin di Acetate, dibutyltin hydroxide, dibutyltin laurate, and the like. These may be used alone or in combination of two or more. The amount of the crosslinking accelerator to be used is usually 0.001 to 0.5 parts by weight, and more preferably 0.001 to 0.3 parts by weight, based on 100 parts by weight of the acrylic polymer.

The pressure-sensitive adhesive composition of the present invention may contain other general additives such as an ultraviolet absorber, a light stabilizer, an anti-aging agent, a peel adjustment agent, a tackifier, a plasticizer, a softener, a filler, a colorant (such as a pigment or a dye) And the like.

The pressure-sensitive adhesive composition of the present invention can be produced by mixing an acrylic polymer and a crosslinking agent, and optionally a nitrogen atom-containing hydroxy compound (particularly, an amine compound containing a plurality of hydroxyl groups) and other crosslinking accelerators and other additives have.

The gel fraction of the cross-linked structured pressure-sensitive adhesive of the present invention (pressure-sensitive adhesive after cross-linking) is preferably 40 to 80%, more preferably 50 to 70% from the viewpoint of balance of anti-foaming and releasability. The gel fraction can be obtained as an ethyl acetate insoluble fraction, specifically, the weight fraction (% by weight) of the insoluble matter after immersion in ethyl acetate at 23 DEG C for 7 days with respect to the sample before immersion. The gel fraction can be controlled by the addition amount of the crosslinking agent, the content of the component B, and the molecular weight of the polymer component. When the gel fraction is less than 40%, foaming tends to occur easily. When the gel fraction is more than 80%, "lifting" and "peeling"

Specifically, the gel fraction (ratio of solvent insoluble matter) is a value calculated by, for example, the following "method for measuring gel fraction".

(Method of measuring gel fraction)

Approximately 0.1 g of the cross-linked structured pressure-sensitive adhesive (pressure-sensitive adhesive after crosslinking) was taken, and it was packed with a porous tetrafluoroethylene sheet (trade name: "NTF1122", manufactured by Nitto Denko K.K.) having an average pore size of 0.2 μm, And the weight is set to the weight before immersion. On the other hand, the weight before immersion is the total weight of the pressure-sensitive adhesive, the tetrafluoroethylene sheet and the smoke chamber. Further, the total weight of the tetrafluoroethylene sheet and the combustion chamber is also measured, and this weight is taken as the weight of the bag.

Next, the pressure-sensitive adhesive is wrapped in a tetrafluoroethylene sheet and bundled into a cylinder (hereinafter referred to as "sample") is placed in a 50 ml container filled with ethyl acetate and left at 23 ° C. for 7 days. Thereafter, a sample (after the treatment with ethyl acetate) is taken out from the vessel, transferred to an aluminum cup, dried in a drier at 130 캜 for 2 hours to remove ethyl acetate, and the weight is measured.

Then, the gel fraction is calculated from the following equation (1).

Gel fraction (% by weight) = (A-B) / (C-B) 100

(In the formula (1), A is the weight after immersion, B is the weight of the bag, and C is the weight before immersion)

For example, it is preferable that the gel fraction of the pressure-sensitive adhesive when the pressure-sensitive adhesive composition is crosslinked and structured at 23 DEG C for 168 hours satisfies the above range. Further, depending on the use, it is preferable that the gel fraction of the pressure-sensitive adhesive when it is crosslinked structured at 50 캜 for 72 hours satisfies the above-mentioned range.

As described above, alkyl (meth) acrylate has been generally used as a main monomer component in the conventional pressure sensitive adhesive (pressure-sensitive adhesive composition). However, the acrylic polymer formed from such a pressure-sensitive adhesive composition has a problem that the storage elastic modulus at a high temperature is lowered, and the foamability and peelability under high temperature and high humidity environments are not sufficient. Therefore, in order to improve the above characteristics, the copolymerization of a high Tg monomer or a functional group-containing monomer (a carboxyl group-containing monomer such as acrylic acid) or the addition of an oligomer (low molecular weight polymer) (Tg) is increased, and the molecular weight of the polymer is increased. However, when the total Tg of the whole system is increased, the storage elastic modulus of the room temperature region is also increased. Therefore, bubbles tend to be easily formed at the time of bonding, and problems such as low temperature and high speed characteristics are deteriorated. Therefore, there is a problem that the coating property is deteriorated and the productivity is deteriorated. Further, in the case of using the carboxyl group-containing monomer such as acrylic acid as the monomer component for the above purpose and the improvement of the adhesiveness and cohesiveness, there is a problem that the internal performance of the metal thin film (metal oxide thin film) . In other words, it was impossible to achieve all of the characteristics such as anti-foaming peelability, internal performance, and low-temperature characteristics (low-temperature adhesion properties) at a high level.

On the contrary, in the present invention, alkoxyalkyl acrylate having a suitable polarity is used as a main monomer component without using a carboxyl group-containing monomer as a monomer component of the pressure-sensitive adhesive, and the monomer composition, molecular weight and degree of crosslinking of the pressure- It has succeeded in achieving compatibility between low-temperature and high-temperature adhesion performance and anti-corrosion performance while satisfying the foamability and peelability. Further, by using the above-mentioned composition, there is no problem such as increase in the viscosity of the polymer due to the fact that the hydrogen bonding is too strong, as in the case of copolymerizing the alkoxyalkyl acrylate and the carboxyl group-containing monomer, An acrylic polymer excellent in coatability can be obtained.

The mechanism of the effect expression by the acrylic polymer constituting the pressure-sensitive adhesive composition of the present invention is not clear, but is estimated as follows. In the present invention, since the alkoxyalkyl acrylate (component A) is used as the main monomer, the Tg of the polymer is relatively low. On the other hand, by the effect of the alkoxyl group of the alkoxyalkyl acrylate and the specific molecular weight in the present invention, appropriate interactions function when the pressure-sensitive adhesive composition is made into a high molecular weight, the entanglement of the polymer chains increases, The storage elastic modulus of the polymer is not lowered even at a high temperature because the entanglement becomes difficult to be released. For this reason, the storage elastic modulus at a high temperature can be kept high even at a relatively low Tg and molecular weight, and satisfactory adhesiveness at low temperature and high speed can be achieved while satisfying both anti-foaming and peeling resistance at high temperatures.

Further, since the acrylic polymer constituting the pressure-sensitive adhesive composition of the present invention does not contain a carboxyl group-containing monomer as a constituent monomer, the resistance value of a metal thin film (metal oxide thin film) such as ITO generated due to an acid component does not occur, It can be suitably used for applications such as laminating ITO films. Although the mechanism of the rise of the resistance value is not clear, the carboxyl group-containing monomer remaining as a monomer at the time of polymerization and the low molecular weight polymer which can be dissolved in water penetrate into the ITO film by moisture under high temperature and high humidity conditions, .

The acrylic polymer constituting the pressure-sensitive adhesive composition of the present invention contains a specific amount of a monomer (component B) having a crosslinkable functional group such as a hydroxyl group and is crosslinked by a crosslinking agent. Therefore, the acrylic polymer can have an appropriate degree of crosslinking, And exhibits an effect of preventing foaming or peeling at a high temperature.

Further, by using an aliphatic isocyanate crosslinking agent as a crosslinking agent and further adding an amine compound containing a plurality of hydroxyl groups, a pressure-sensitive adhesive composition that is compatible with a high level of flame retardancy, productivity, and appearance can be obtained.

[Adhesive products]

By applying the pressure-sensitive adhesive composition of the present invention onto a substrate or a release liner to form a pressure-sensitive adhesive layer, a pressure-sensitive adhesive product is obtained. The adhesive product of the present invention includes, for example, an adhesive sheet, an adhesive tape, and the like. The adhesive product of the present invention may be in the form of a sheet-like (base-less leased) substrate or a tape-like one obtained by coating the pressure-sensitive adhesive composition on a release liner, It may be in the form of a sheet on which a pressure-sensitive adhesive layer is provided or in the form of a tape.

The thickness of the pressure-sensitive adhesive layer (coating thickness of the pressure-sensitive adhesive composition, thickness after drying) is not particularly limited and is, for example, preferably 5 to 1000 占 퐉, more preferably 10 to 100 占 퐉. On the other hand, the pressure-sensitive adhesive layer may have any form of a single layer or a laminate.

The gel fraction of the pressure-sensitive adhesive layer (cross-linked structured pressure-sensitive adhesive) is preferably from 40 to 80%, more preferably from 50 to 70%, as described above from the viewpoint of balance of anti-foaming and releasability.

When the pressure-sensitive adhesive layer is provided on a substrate, the substrate is not particularly limited, but various optical films such as a plastic film, an antireflection (AR) film, a polarizing plate and a retardation plate can be given. Examples of the material of the plastic film and the like include polyester such as polyethylene terephthalate (PET), acrylic resin such as polymethyl methacrylate (PMMA), polycarbonate, triacetylcellulose, polysulfone, polyarylate, And plastic materials such as "Atton (cyclic olefin polymer: manufactured by JSR Corporation)" and "Zeonor (cyclic olefin polymer; manufactured by Nippon Zeon Co., Ltd.)". On the other hand, the plastic materials may be used alone or in combination of two or more. The thickness of the substrate is not particularly limited, and is preferably 10 to 1000 mu m, for example. On the other hand, the substrate may have a single-layer structure or a multi-layer structure. The substrate surface may be subjected to appropriate known or conventional surface treatment such as chemical treatment such as physical treatment such as corona discharge treatment and plasma treatment, priming treatment and the like.

Meanwhile, in the production of the pressure sensitive adhesive product of the present invention, a known coating method can be used for coating the pressure-sensitive adhesive composition, and conventional coaters such as a gravure roll coater, a reverse roll coater, a kiss roll coater, , A bar coater, a knife coater, a spray coater, or the like.

The pressure-sensitive adhesive layer portion of the pressure-sensitive adhesive product of the present invention preferably has high transparency when used in optical applications such as displays, and for example, has a total light transmittance (in accordance with JIS K 7361) in a visible light wavelength region of 90 % Or more, more preferably 91% or more. The haze value (in accordance with JIS K 7136) of the pressure-sensitive adhesive layer portion in the adhesive product is preferably, for example, less than 1.0%, more preferably less than 0.8%. On the other hand, the total light transmittance and the haze are measured by a haze meter (manufactured by Murakami Color Research Laboratory, product name: "HM-150 " "). ≪ / RTI >

The adherend of the adhesive product (pressure-sensitive adhesive sheet, pressure-sensitive adhesive tape) is not particularly limited, and examples thereof include an acrylic resin plate, a polycarbonate plate, glass, and polyethylene terephthalate.

The adhesive product of the present invention is preferably used for displays such as a plasma display panel (PDP), a touch panel, and a liquid crystal panel. Among them, it is particularly preferably used for the purpose of directly bonding and fixing to a metal thin film such as a touch panel, from the viewpoints of the corrosion resistance, transparency and adhesive property.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Acrylic Polymer Production Example 1

(Acrylic Polymer A)

As a monomer component, 70 parts by weight of 2-methoxyethyl acrylate, 29 parts by weight of 2-ethylhexyl acrylate, 1 part by weight of 4-hydroxybutyl acrylate, and 2,2'-azobisisobutyronitrile : 0.2 part by weight and ethyl acetate as a polymerization solvent: 100 parts by weight were charged in a separable flask and stirred for 1 hour while introducing nitrogen gas. After the oxygen in the polymerization system was removed in this way, the temperature was raised to 63 ° C and the reaction was carried out for 10 hours. Then, toluene was added to the solution to obtain an acrylic polymer solution having a solid concentration of 25% by weight (sometimes referred to as "acrylic polymer solution A" . The weight average molecular weight of the acrylic polymer (sometimes referred to as "acrylic polymer A") in the acrylic polymer solution A was 1.5 million.

(Acrylic Polymers B to K)

As shown in Table 1, the kind of the monomer components, the amount of the monomer components, and the amount of the solvent (ethyl acetate) were changed to obtain acrylic polymer solutions (sometimes referred to as "acrylic polymer solutions B to K"). The weight average molecular weights of the acrylic polymers (sometimes referred to as "acrylic polymers B to K ", respectively) in the acrylic polymer solutions B to K are shown in Table 1.

Example 1

0.3 part by weight of a polyfunctional isocyanate compound (trade name: "Colonate L ", manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent was added to 100 parts by weight of acrylic polymer solution A (100 parts by weight of acrylic polymer A) To prepare a pressure-sensitive adhesive composition (solution).

The solution obtained above was applied on the releasable surface of a polyethylene terephthalate (PET) film (thickness: 38 mu m) (release liner) obtained by releasing the surface thereof to a thickness of about 25 mu m after drying, Followed by aging at 50 캜 for 72 hours to prepare a pressure-sensitive adhesive sheet of base-less resin.

Examples 2 to 8 and Comparative Examples 1 to 5

As shown in Table 2, a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet were prepared in the same manner as in Example 1, except that the kind of the acrylic polymer solution and the blending amount of the crosslinking agent were changed.

[evaluation]

The pressure-sensitive adhesive compositions and pressure-sensitive adhesive sheets obtained in Examples 1 to 8 and Comparative Examples 1 to 5 were evaluated for coatability, transparency, adhesiveness (low temperature adhesion property), anti-foaming peelability and corrosion resistance by the following measuring methods or evaluation methods Respectively. The evaluation results are shown in Table 2. On the other hand, the gel fraction in Table 2 is the value of the gel fraction of the pressure sensitive adhesive collected from the pressure sensitive adhesive sheet.

(1) Transparency (total light transmittance, haze value)

Each of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples was bonded to a slide glass (trade name "S-1111" manufactured by Matsunami Glass Co., Ltd., total light transmittance: 91.8%, haze value: 0.4% The film was peeled off to prepare a test piece having a layer structure of a pressure-sensitive adhesive layer / a slide glass. The haze value (%) of the test piece was measured using a haze meter (trade name: "HM- 150 ", manufactured by Murakami Color Research Laboratory) . On the other hand, the haze value (%) was obtained by using the equation "diffusion transmittance / total light transmittance × 100".

When the haze value is less than 1.0%, transparency is good (O), and when it is 1.0% or more, it is poor (X).

(2) Coating property

In the examples and comparative examples, when the pressure-sensitive adhesive sheet was produced by flexibly applying the obtained pressure-sensitive adhesive solution (pressure-sensitive adhesive composition) at a coating rate of 1 to 10 m / min to a PET film (release liner) subjected to release treatment, (?), Coating streaks or the like were generated in which the coated surface was smooth and no smooth surface was formed, and it was judged that the coating was poor (x). On the other hand, the judgment was made with naked eyes.

(3) Corrosion resistance

PET film (trade name: "Rumilas S-10 # 25 ", manufactured by Toray Co., Ltd., thickness: 25 μm) was bonded to the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, cut into a size of 20 mm × 50 mm, Respectively.

As shown in Fig. 1, a silver paste was applied to both ends of a conductive PET film (trade name: "ELEKORZA P400L-TNMP ", trade name; manufactured by Nitto Denko K.K .; size: 70 mm x 25 mm) The adhesive surface of the test piece 1 with the release liner peeled off was bonded to the surface (on the side of the ITO film formation surface 2) of the test piece 1. This was allowed to stand for 250 hours under the conditions of 60 ° C and 95% RH and 80 ° C, The resistance value was measured by attaching an electrode to the silver paste portion 3 at both ends using "Digital Millimeter High Testers Part No. 3540" manufactured by Hioki Denki Co., Ltd. Respectively.

When the rate of change of the resistivity was less than 120%, the corrosion resistance was good (), and when the rate of resistance was 120% or more, the corrosion resistance was poor ().

On the other hand, as the blank, the same test was conducted using only the conductive PET film not adhering the adhesive sheet, and as a result, it was 120% under the condition of 110% at 80 캜 and 95% RH at 60 캜.

(4) Foam peelability

The pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples was bonded to a PET film (trade name "A4300", manufactured by Toyo Boseki Co., Ltd., thickness: 125 μm) to prepare a film piece having a width of 100 mm and a length of 100 mm.

The release liner was peeled off from the film piece and fixed to a polycarbonate (PC) plate (trade name: "Panlite PC1111", thickness: 1 mm, manufactured by DAIJIN KASEI CO., LTD.) To fix the PET film / pressure- ≪ / RTI > was prepared.

The sample piece was subjected to heat treatment (heat resistance test) in an oven at 80 캜 for 5 hours. After the heat resistance test, the sample pieces were visually observed at the adhesive interface (interface between the pressure-sensitive adhesive layer and the PC plate), and when no "bubble" or " "And" peel-off "were found to be slight, it was judged that the defective peeling property was poor (×).

(5) Low temperature adhesion property

2, an acrylic plate 41 (length 70 mm x width 50 mm x thickness 2.0 mm) (trade name "Acrylite ", manufactured by Mitsubishi Rayon Co., Ltd.) and PET film (manufactured by Toyo Boseki Co., An acrylic plate 42 (120 mm long × 50 mm wide) obtained by bonding an adhesive sheet 43 (trade name "A4300, # 125" mm) to prepare a measurement sample (4). The bonding (pressing) was performed under one reciprocating condition using a 5 kg roller, and the bonding area was 10 mm x 50 mm.

The sample for measurement was autoclaved at 50 DEG C under a pressure of 5 atm for 30 minutes and then aged for 24 hours under an atmosphere of 50 DEG C and normal pressure and allowed to stand for 3 hours at a measurement temperature (-30 DEG C) .

As shown in Figs. 3 to 5, the measurement sample was set in an impact testing apparatus, and an impact test was performed at an angle of 10 DEG to 90 DEG at 10 DEG in an environment of -30 DEG C, 41) were measured. Details of the impact test method and the test apparatus are as follows.

[Impact test apparatus, test method]

(i) Test equipment

Fig. 3 shows a schematic view of the test apparatus. The test apparatus 5 is composed of a rectangular frame (long side 610 mm, short side 322 mm) made of stainless steel plate having a plate thickness of 6 mm and an L-shaped cross section (one side of L letter and 50 mm on the other side) A rectangular frame (long side 1010 mm, short side 322 mm) made of a stainless steel plate having a plate thickness of 3 mm and an L-shaped cross section (one side of the L letter and the other side of 25 mm each) The second angle 52 is vertically erected and the upper frame 52A of the second angle 52 is formed with an L-shaped cross section having a thickness of 3 mm and one side of the L- The upper frame 53A of the third angle 53 (total weight 3.3 kg) made of a rectangular frame made of a stainless steel plate (long side 915 mm and short side 310 mm) is connected by a hinge so that the third angle 53 Is rotated with respect to the second angle (52).

As shown in Fig. 4, the measurement sample 4 is held as a sample retaining section with the U-shaped cross section of the lower end frame 53B of the third angle 53 (20 from the lower end of the acrylic plate 42) lt; RTI ID = 0.0 > mm). < / RTI >

(ii) Test method

5, the third angle 53 is lifted up to a position at a predetermined angle? With respect to the second angle 52, and then the second angle 52 (As shown by the arrow a). This operation is performed by changing the angle [alpha].

6, a force (an inertial force) is applied to the acrylic plate 41 in the direction of the arrow b in the drawing. By this force, the acrylic plate 41 is moved from the acrylic plate 42 The angle of peeling was measured.

On the other hand, the angle? (Measurement angle) was increased by 10 degrees from 10 to 90 degrees.

As is clear from the results of Tables 1 and 2, the pressure-sensitive adhesive composition satisfying the requirements of the present invention is excellent in coating properties, and the pressure-sensitive adhesive layer and the pressure-sensitive adhesive sheet formed from the pressure- And it is excellent in the foaming and peeling property. Further, there is no problem that the adherend is adhered to the conductive film to corrode the adherend even if it is stored for a long time under a high-temperature environment or a high-temperature and high-humidity environment (Example).

Further, in the pressure-sensitive adhesive sheets of Examples 1, 3, and 8, no peeling of the acrylic plate was observed even at a measurement angle of 90 degrees in the test (impact test) of the low temperature adhesion property. Further, in Examples 2 and 4 to 7, peeling of the acrylic plate was observed at a measurement angle of 50 °, and good low-temperature bonding properties were exhibited. In addition, the transparency of the pressure-sensitive adhesive sheet of the examples was all good (O).

On the other hand, when the blending amount of the alkoxyalkyl acrylate as the component A was small (Comparative Examples 1 and 4) or when the molecular weight of the acrylic polymer was too small (Comparative Example 3), the anti-foaming and peeling properties were deteriorated. In addition, when the molecular weight of the acrylic polymer was too large (Comparative Example 5), the coating properties were deteriorated. Further, in the case of using acrylic acid (carboxyl group-containing monomer) as the monomer component (Comparative Example 2), there was a problem that the adherend was corroded when it was stored for a long period under a high temperature and high humidity environment.

Next, the effect of improving the vulcanization resistance and productivity in the case of using an amine compound containing an aliphatic isocyanate crosslinking agent and a plurality of hydroxyl groups will be described on the basis of examples. However, the present invention is not limited to these examples.

Production Example 2 of Acrylic Polymer

(Acrylic polymer L)

As shown in Table 3, a predetermined amount of a monomer component and ethyl acetate as a polymerization solvent were put into a separation flask, and stirred for 1 hour while introducing nitrogen gas. After the oxygen in the polymerization system was removed in this manner, the temperature was raised to 63 ° C and 0.2 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator was added. After 10 hours of reaction, MEK (methyl ethyl ketone) was added , And an acrylic polymer solution having a solid content concentration of 25% by weight (sometimes referred to as "acrylic polymer solution L").

(Acrylic Polymers M to T)

As shown in Table 3, the acrylic polymer solution (sometimes referred to as "acrylic polymer solution M to T" in some cases) was obtained by changing the kind of monomer component, blending amount and blending amount of solvent (ethyl acetate).

On the other hand, the weight average molecular weights of the acrylic polymers (sometimes referred to as "acrylic polymers L to T ", respectively) in the acrylic polymer solutions L to T are shown in Table 3.

Example 9

An aliphatic polyfunctional isocyanate compound (trade name: "Colonate HL ", trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent was added to 100 parts by weight of acrylic polymer L (100 parts by weight of acrylic polymer L) And 0.3 part by weight of a polyol obtained by adding propylene oxide to ethylene diamine as a crosslinking aid (manufactured by ADEKA, trade name "EDP-300") were added to prepare a pressure-sensitive adhesive composition (solution).

The solution obtained above was applied on the releasable surface of a polyethylene terephthalate (PET) film (thickness: 38 mu m) (release liner) obtained by releasing the surface thereof to a thickness of about 25 mu m after drying, Dried for 3 minutes, and further aged at 23 캜 for 7 days to prepare a pressure-sensitive adhesive sheet of base-less resin.

Examples 10 to 23 and Comparative Examples 6 to 10

As shown in Tables 4 and 5, a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet were prepared in the same manner as in Example 9, except that the kind of the acrylic polymer solution and the type and amount of the crosslinking agent and the crosslinking aid were changed.

[evaluation]

The pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet obtained in Examples 9 to 23 and Comparative Examples 6 to 10 were evaluated for coatability, transparency, anti-foaming peelability, corrosion resistance, productivity (crosslinking degree increasing method), vulcanization resistance Value) was evaluated.

On the other hand, the measurement method or evaluation method of transparency, coatability, corrosion resistance and anti-foaming peelability are the same as those of the above-described evaluation methods (1) to (4). The ascending method and the vulcanization denaturation of the crosslinking degree were evaluated by the following measuring method or evaluation method. The evaluation results are shown in Tables 4 and 5. The gel fractions in Tables 4 and 5 are values of the gel fraction of the pressure sensitive adhesive collected from the pressure sensitive adhesive sheet.

(6) Increasing the degree of crosslinking (productivity)

The pressure-sensitive adhesive compositions obtained in Examples and Comparative Examples were applied on a release-treated surface of a PET film which had been subjected to releasing treatment on the surface thereof so as to have a thickness of about 25 탆 after drying and then heated and dried at 130 캜 for 3 minutes to form a pressure- Respectively. The thus obtained pressure-sensitive adhesive layer was subjected to aging under two different aging conditions of 50 占 폚 for 24 hours and 23 占 폚 for 168 hours (seven days) to prepare a sample of the pressure-sensitive adhesive (pressure-sensitive adhesive after crosslinking).

Approximately 0.1 g of a pressure-sensitive adhesive (pressure-sensitive adhesive after crosslinking) under the above aging conditions (50 DEG C for 24 hours and 23 DEG C for 168 hours) was taken and the gel fraction (% by weight) was calculated according to the above-mentioned " .

(&Quot; Gel fraction of 24 hours at 50 占 폚 for 24 hours at 50 占 폚 for 24 hours) and gel fraction (referred to as "Gel fraction of 168 hours at 23 占 폚 for 168 hours at 23 占 폚) (%) Of the degree of crosslinking was calculated using the formula.

Increase of crosslinking ratio (%) = (gel fraction at 23 占 폚 for 168 hours) / (gel fraction at 50 占 폚 for 24 hours) 占 100

On the other hand, the larger the crosslinking degree rise method is, the more easily the crosslinking reaction proceeds at room temperature and the productivity is good.

(7) Moisture denaturation (b value after heat treatment at 80 캜 for 500 hours, b value after heat treatment at 80 캜 for 1000 hours)

Samples (each of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples) were subjected to heat treatment under predetermined conditions (80 ° C for 500 hours and 80 ° C for 1000 hours), and then transferred onto a slide glass (trade name "S- 1111 ", was adhered to the 91.8% total light transmittance, haze value 0.4%), and exposing the adhesive layer (PET film was peeled off), by the spectrophotometer DOT-3C of manufacture by Murakami color Lab L ^* a ^* b ^* b in the color coordinate system The values were evaluated.

On the other hand, the transparency of the examples was all good (O).

As apparent from the results of Tables 3 to 5, the pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet using a predetermined amount of the aliphatic isocyanate crosslinking agent and the crosslinking aid of the amine-based compound containing a plurality of hydroxyl groups are excellent in coatability, Not only was excellent in corrosion resistance, but also showed excellent yellowing resistance without yellowing even when heated for a long period of time. Further, the crosslinking degree also increased relatively quickly even at a temperature condition of 23 캜 and productivity was excellent (Examples 9 to 20).

On the other hand, when an aromatic isocyanate crosslinking agent is used or when a crosslinking aid of an amine compound containing a plurality of hydroxyl groups is not used in an appropriate amount, properties such as coatability, anti-foaming / peeling property and corrosion resistance are excellent However, the yellowing was somewhat remarkable, the crosslinking degree was slow, and aging at 23 DEG C for 168 hours resulted in inadequate crosslinking, so that the productivity could not be made high at a high level in the absence of yellowing resistance and warming ( Examples 21 to 23).

On the other hand, even when the crosslinking aid of an amine compound containing an aliphatic isocyanate crosslinking agent and a plurality of hydroxyl groups is used, when the component A or the component B is not used as a monomer component or when acrylic acid is used, If it is not in an appropriate range, there is a problem of coating property, anti-foaming / peeling property, and corrosion resistance, and the effect of the present invention can not be obtained (Comparative Examples 6 to 10).

1 is a schematic view showing a resistance value measurement sample used for evaluation of corrosion resistance in the embodiment.

2 is a schematic sectional view (2a) and a schematic front view (2b) showing a sample for measurement used for testing low-temperature bonding properties.

3 is a schematic view showing a test apparatus used for testing low-temperature adhesion properties.

Fig. 4 is a schematic sectional view showing a sample holding portion of the test apparatus of Fig. 3;

5 is a schematic view (a schematic side view of the test apparatus) showing a test method for low-temperature adhesion properties.

6 is a schematic view showing the force applied to the sample for measurement in the test of the low-temperature bonding property.

DESCRIPTION OF THE REFERENCE NUMERALS

1 specimen

2 Conductive PET film (exposed part of the ITO film forming side)

3 Conductive PET film (silver paste applied portion)

4 Sample for measurement

   41 acrylic plate

   42 An acrylic plate with a PET film bonded to the surface with an adhesive

      42a PET film

      42b acrylic plate

   43 Adhesive sheet

5 Impact testing device

   51 1st angle

   52 2nd angle

      52A Top frame of 2nd angle

   53 Third angle

      53A Top frame of 3rd angle

      53B Lower frame of third angle

α measurement angle

a The direction of movement of the third angle in the impact test

b Direction of force applied to the acrylic plate in the impact test

Claims (6)

An acrylic polymer having a weight average molecular weight of 400,000 to 1,600,000 and an acrylic monomer having an alkoxyalkyl acrylate (component A) and an acrylic monomer having a crosslinkable functional group (component B) as essential monomer components and a crosslinking agent, Wherein the content of the component A is 45 to 99.5 parts by weight based on 100 parts by weight of the monomer component, the content of the component B is 0.5 to 4.5 parts by weight, the content of the carboxyl group-containing monomer in the monomer component constituting the acrylic polymer is 100 parts by weight And less than 0.05 part by weight of the pressure-sensitive adhesive composition. The positive resist composition as claimed in claim 1, which comprises 100 parts by weight of an acrylic polymer having an alkoxyalkyl acrylate (component A) and an acrylic monomer having a crosslinkable functional group (component B) as essential monomer components and having a weight average molecular weight of 400,000 to 1,600,000, 0.01 to 3.0 parts by weight of an aliphatic isocyanate crosslinking agent and 0.01 to 5.0 parts by weight of an amine compound containing a plurality of hydroxyl groups and the content of the component A relative to 100 parts by weight of the total monomer component constituting the acrylic polymer is 45 To 99.5 parts by weight, the content of component B is 0.5 to 4.5 parts by weight, and the content of the carboxyl group-containing monomer in the monomer component constituting the acrylic polymer is less than 0.05 part by weight based on 100 parts by weight of the total monomer components . The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the component B is an acrylic monomer having a hydroxyl group. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the gel fraction after cross-linking is 40 to 80%. A pressure-sensitive adhesive product to which the pressure-sensitive adhesive composition according to claim 1 or 2 is applied. A display using the adhesive product according to claim 5.

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