KR101742846B1 - Method of solvent-type adhesive composition with excellent polymerization stability - Google Patents

Abstract

Preparing a first mixed solution comprising a polymerization monomer containing 15 to 70 parts by weight of a hydrophilic functional group-containing monomer per 100 parts by weight of the (meth) acrylic acid ester monomer and an organic solvent for polymerization; Adding a photopolymerization initiator to the first mixed solution to prepare a second mixed solution; And irradiating ultraviolet light to the second mixed solution to initiate a photopolymerization reaction to form an acrylic copolymer resin.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a solvent-type pressure-

To a process for producing a solvent-type pressure-sensitive adhesive composition excellent in polymerization reaction stability.

Four methods of solution polymerization, emulsion polymerization, pearl polymerization and bulk polymerization are generally used as methods for producing acrylic polymers by polymerizing acrylic monomers.

Among them, the bulk polymerization method uses a peroxide-based or azo-based initiator which is initiated by heat as a polymerization initiator. In order to cause a polymerization reaction, a certain amount of heat must be supplied to the inside of the reaction system. There is a problem that the decomposition of the initiator is accelerated successively by the polymerization heat generated during the polymerization reaction and the reaction proceeds explosively. In addition, since there is no dispersion medium for controlling the heat of polymerization occurring during the reaction of the solvent or water or for dissolving or dispersing the generated polymer, the polymer produced through the polymerization reaction at the initial stage of the polymerization reaction is dissolved by the unreacted acrylic monomer as a solvent However, when the polymerization rate is increased over time, the acrylic monomer used as a solvent sharply decreases and the viscosity of the polymerization reaction rapidly increases.

Therefore, there is a need for an acrylic polymerization method capable of solving the problem of progress of explosive reaction and high viscosity.

One embodiment of the present invention provides a method for producing a solvent-type pressure-sensitive adhesive composition which is excellent in stability during a polymerization reaction even though it contains a large amount of hydrophilic functional group-containing monomer.

Another embodiment of the present invention provides an acrylic copolymer resin having a low molecular weight and a high molecular weight.

In one embodiment of the present invention, a first mixed solution comprising a polymerization monomer containing 15 to 70 parts by weight of a hydrophilic functional group-containing monomer relative to 100 parts by weight of the (meth) acrylic acid ester-based monomer and an organic solvent for polymerization reaction Lt; / RTI > Adding a photopolymerization initiator to the first mixed solution to prepare a second mixed solution; And irradiating ultraviolet light to the second mixed solution to initiate a photopolymerization reaction to form an acrylic copolymer resin.

The conversion of the polymerization monomer to the acrylic copolymer resin may be about 70% or more.

The weight average molecular weight of the acrylic copolymer resin prepared by the method for preparing a solvent-type pressure-sensitive adhesive composition may be about 1 million to about 350.

The acrylic copolymer resin produced by the method for preparing a solvent-type pressure-sensitive adhesive composition may have a weight average molecular weight distribution (PolyDispersity Index) of about 1 to about 5. [

The glass transition temperature of the acrylic copolymer resin produced by the method for preparing a solvent-type pressure-sensitive adhesive composition may be about -20 캜 or lower.

The (meth) acrylate monomer may be at least one selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (Meth) acrylate, isononyl (meth) acrylate, isononyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Ethylbutyl (meth) acrylate, and combinations thereof.

The hydrophilic functional group-containing monomer may be at least one selected from the group consisting of a hydroxyl group-containing monomer, an amino group-containing monomer, a carboxyl group-containing monomer, a sulfonic group-containing monomer, a morpholine group-containing monomer and a glycidyl group-containing monomer.

The organic solvent for polymerization may be about 10 parts by weight to about 900 parts by weight based on 100 parts by weight of the polymerization monomer.

The organic solvent for polymerization may be at least one selected from the group consisting of ethyl ether, acetone, acetonitrile, petroleum ether, isopropyl alcohol, methanol, ethanol, n-pentane, n-hexane, benzene, dichloromethane, trichloromethane, methyl acetate, At least one member selected from the group consisting of glycol dimethyl ether, methyl ethyl ketone, trichloromethane, tetrachloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, n-hexane, cyclohexane, .

The photopolymerization initiator may be about 0.1 part by weight to about 5 parts by weight based on 100 parts by weight of the polymerization monomer.

The photopolymerization initiator may be at least one selected from the group consisting of a benzoin compound, a hydroxy ketone compound, an amino ketone compound, a phosphine oxide compound, and combinations thereof.

The ultraviolet irradiation may be performed at a wavelength of about 100 nm to about 400 nm.

The exothermic temperature during the photopolymerization reaction may be about 0.5 ° C to about 10 ° C.

Adding 0.02 parts by weight to 2.0 parts by weight of at least one additive selected from the group consisting of a crosslinking agent, a curing agent, a coupling agent, and a combination thereof to 100 parts by weight of the acrylic copolymer resin.

In another embodiment of the present invention, there is provided an acrylic copolymer resin having a weight average molecular weight of 1,000,000 to 3,500,000, wherein the acrylic copolymer resin has a molecular weight distribution (Poly Dispersity Index) of 1 to 5 or less, And a glass transition temperature of about -20 占 폚 to about -45 占 폚.

The peel strength of the solvent-type pressure-sensitive adhesive composition may be about 1,700 g / in to about 2,400 g / in.

The haze value of the solvent-type pressure-sensitive adhesive composition may be about 0.1% to about 0.5%.

The method of preparing the solvent-type pressure-sensitive adhesive composition is advantageous in terms of cost because of short polymerization time and low temperature during polymerization, and is capable of controlling the reaction heat and thus has excellent polymerization stability.

The solvent-type pressure-sensitive adhesive composition and the pressure-sensitive adhesive film containing the solvent-type pressure-sensitive adhesive composition according to the present invention can be produced without clouding under high temperature and high humidity conditions.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

In one embodiment of the present invention, a first mixed solution comprising a polymerization monomer containing 15 to 70 parts by weight of a hydrophilic functional group-containing monomer relative to 100 parts by weight of the (meth) acrylic acid ester-based monomer and an organic solvent for polymerization reaction Lt; / RTI > Adding a photopolymerization initiator to the first mixed solution to prepare a second mixed solution; And irradiating ultraviolet light to the second mixed solution to initiate a photopolymerization reaction to form an acrylic copolymer resin.

Generally, the polymerization reaction is a thermochemical polymerization reaction and a photochemical polymerization reaction. In the thermochemical polymerization process, a radical reaction is formed by the thermal decomposition reaction, so that a large amount of heat is required, There are long disadvantages. In addition, when the functional group-containing monomer is introduced in an amount exceeding a certain amount in order to improve the adhesive property of the composition prepared by the thermal polymerization reaction, a large amount of the reaction heat is generated, so that the stability of the polymerization reaction is poor and the reaction is difficult to proceed.

On the other hand, in the photochemical polymerization method, unlike a general thermochemical polymerization reaction which requires a large amount of heat, polymerization can be carried out at room temperature, so that the polymerization reaction is easily controlled and the polymerization time is short. Even when a large amount of functional group- The temperature can be controlled and a large amount of reaction heat is not generated, the polymerization reaction can be continued and the adhesion performance of the composition formed by photopolymerization can be improved.

Accordingly, an embodiment of the present invention provides a method for manufacturing a solvent-type pressure-sensitive adhesive composition which enables the polymerization reaction to be controlled stably while allowing the polymerization monomer to contain a hydrophilic functional group-containing monomer in a certain amount or more.

When a pressure sensitive adhesive sheet is formed from a solvent type pressure sensitive adhesive composition prepared by introducing a hydrophilic functional group-containing monomer having a certain content or more, the pressure sensitive adhesive sheet has a peeling force of a certain level or higher and, at the same time, The anti-clouding performance can be exhibited.

Specifically, the polymerization monomer may contain about 15 parts by weight to about 70 parts by weight of the hydrophilic functional group-containing monomer relative to 100 parts by weight of the (meth) acrylic acid ester-based monomer. The method of preparing the solvent-type pressure-sensitive adhesive composition forms an acrylic copolymer resin through a photopolymerization reaction, and even when a large amount of the hydrophilic functional group-containing monomer is contained, the polymerization reaction is not unstable.

When the hydrophilic functional group-containing monomer is contained in an amount of less than about 15 parts by weight based on 100 parts by weight of the (meth) acrylate-based monomer, there is a fear of cloudiness, and when the monomer is contained in an amount exceeding about 70 parts by weight, .

Therefore, by including the hydrophilic functional group-containing monomer within the above range, the polymerization stability can be secured, the occurrence of clouding can be suppressed, and the durability can be easily improved.

The conversion of the polymerization monomer to the acrylic copolymer resin may be about 70% or more. The conversion rate refers to a rate at which the polymerization monomer is converted into the acrylic copolymer resin, specifically, about 85% to about 99%. When the polymerization monomer is photopolymerized, the viscosity rises sharply with the polymerization reaction time, resulting in a conversion of less than about 70%. In the method for producing a solvent type composition, the organic solvent for dilution is added during the polymerization reaction to lower the viscosity, And can be implemented at about 70% or more.

The weight average molecular weight of the acrylic copolymer resin prepared by the method for preparing a solvent-type pressure-sensitive adhesive composition may be about 1 million to about 350. The weight average molecular weight means an average weight average molecular weight obtained by averaging the weight average molecular weight of the component molecular species of the polymer compound having a weight average molecular weight distribution by a weight fraction and is determined by a photopolymerization reaction by controlling the content of the hydrophilic functional group- It is possible to produce an acrylic copolymer resin having a low molecular weight and an acrylic copolymer resin having a high molecular weight with ease of control.

By keeping the weight average molecular weight of the acrylic copolymer resin within the above range, it is possible to secure a solvent-type pressure-sensitive adhesive composition excellent in cutting property and workability and having mechanical strength and stable physical properties even at high temperatures, Can be extended.

The acrylic copolymer resin produced by the method for preparing a solvent-type pressure-sensitive adhesive composition may have a weight average molecular weight distribution (PolyDispersity Index) of about 1 to about 5. [ Since the ordinary polymer compound is a molecular species compound having a different weight average molecular weight, it has a weight average molecular weight and a polydispersity, and thus the acrylic copolymer resin may have a weight average molecular weight distribution. The weight average molecular weight distribution refers to a ratio of a weight average molecular weight (Mw) to a number average weight average molecular weight (Mn), and can be measured using gel permeation chromatography (GPC). As the weight average molecular weight distribution is larger, Means that the weight average molecular weight is distributed widely throughout the molecular weight, and the smaller the weight average molecular weight distribution is, the narrower the weight average molecular weight is distributed around the weight average molecular weight.

As the weight average molecular weight distribution becomes wider, the shear stress decreases and the workability improves. However, the mechanical strength and durability of the pressure-sensitive adhesive composition deteriorate, and as the weight average molecular weight distribution narrows, the mechanical strength and durability are improved, but the workability may be lowered.

The weight average molecular weight distribution of the acrylic copolymer resin prepared by the method for producing a solvent type pressure-sensitive adhesive composition is measured in the above-described range, which is excellent in that not only mechanical strength and durability but also workability of the pressure-sensitive adhesive composition can be increased. Mechanical strength and durability may be deteriorated and the workability may also be deteriorated.

The glass transition temperature of the acrylic copolymer resin produced by the above solvent-type pressure-sensitive adhesive composition manufacturing method may be about -20 캜 or less, specifically about -45 캜 to -25 캜. If the glass transition temperature of the prepared acrylic copolymer resin is out of the above range, the modulus of elasticity is excessively increased, resulting in deterioration of the tackiness and deterioration of cuttability and workability.

The (meth) acrylate monomer may be at least one selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (Meth) acrylate, isononyl (meth) acrylate, isononyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Ethylbutyl (meth) acrylate, and combinations thereof.

The hydrophilic functional group-containing monomer may be at least one selected from hydroxyl group-containing monomers, amino group-containing monomers, carboxyl group-containing monomers, sulfonic group-containing monomers, morpholine group-containing monomers and glycidyl group-containing monomers.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylic acid hydroxyalkyl esters such as 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate and (4-hydroxymethylcyclohexyl) methyl Acryloyloxyethyl-2-hydroxyethylphthalic acid, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylate, Containing monomers including primary hydroxyl group-containing monomers such as (meth) acrylamide; Hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2- Acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and other secondary hydroxyl group-containing monomers; And tertiary hydroxyl group-containing monomers such as 2,2-dimethyl-2-hydroxyethyl (meth) acrylate.

Typically, the transparent pressure-sensitive adhesive composition is composed of an acrylic-based monomer, and includes an acid component such as acrylic acid. Accordingly, various acid components present in the transparent pressure-sensitive adhesive composition on the touch pad side oxidize the conductive layer composed of ITO, which may increase the resistance of the conductive layer and deteriorate the properties of the touch pad.

In order to solve this problem, when a non-acid type monomer is used, among the above-mentioned hydroxyl group-containing monomers, when 2-hydroxyethyl acrylate is used, the acrylic copolymer resin is an acid- So that it can be applied to a display material.

Examples of the amino group-containing monomer include dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate.

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic acid, itaconic acid, fumaric acid, acrylamide N-glycolic acid, cinnamic acid, Michael adducts of (meth) acrylic acid (Methacrylic acid dimmer, acrylic acid trimer, methacrylic acid trimer, acrylic acid tetramer, methacrylic acid tetramer, etc.), 2- (meth) acryloyloxyethyldicarboxylic acid monoester Acryloyloxyethylphthalic acid monoester, 2-methacryloyloxyethylphthalic acid monoester, 2-acryloyloxyethylphthalic acid monoester, 2-acryloyloxyethylphthalic acid monoester, 2-acryloyloxyethylphthalic acid monoester, Hydrofluoric acid monoester, 2-methacryloyloxyethylhexahydrophthalic acid monoester, etc.) and the like.

For example, when acrylic acid is used as the hydrophilic functional group-containing monomer, an acid type acrylic copolymer resin containing an acid (aicd) can be formed, which can be used for industrial and domestic use. Can be used.

Examples of the sulfone group-containing monomer include olefin sulfone such as ethylene sulfone, allyl sulfone, and methallylsulfone, 2-acrylamide-2-methylpropanesulfone, styrenesulfone or salts thereof. Examples of the monomer containing morpholine group include 4-methylmorpholine, and examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

The organic solvent for polymerization may be about 10 parts by weight to about 900 parts by weight based on 100 parts by weight of the polymerization monomer. By including the organic solvent within the above range, it is possible to solve the problem that agitation and processing become difficult due to an increase in viscosity which is increased as the weight average molecular weight increases during photopolymerization.

Specifically, the polymerization reaction organic solvent is not particularly limited. However, when the drying time of the organic solvent is too long or when it is necessary to dry at a high temperature, a problem may arise in terms of workability or durability of the solvent-type pressure-sensitive adhesive composition, so that a solvent having a volatilization temperature of about 100 ° C or less is used . In consideration of the moldability of the solvent-type pressure-sensitive adhesive composition, a small amount of an organic solvent having a volatilization temperature higher than the above range may be mixed and used.

For example, the organic solvent for polymerization may be at least one selected from the group consisting of ethyl ether, acetone, acetonitrile, petroleum ether, isopropyl alcohol, methanol, ethanol, n-pentane, n-hexane, benzene, dichloromethane, trichloromethane, Ethyl acetate, ethylene glycol dimethyl ether, methyl ethyl ketone, trichloromethane, tetrachloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, n-hexane, cyclohexane and combinations thereof . ≪ / RTI >

The photopolymerization initiator may be about 0.1 part by weight to about 5 parts by weight based on 100 parts by weight of the polymerization monomer. If the content of the photopolymerization initiator is less than about 0.1 parts by weight, polymerization or curing reaction may not be performed smoothly. If the content is more than about 5 parts by weight, physical properties such as durability and transparency may be deteriorated.

The photopolymerization initiator may be at least one selected from the group consisting of a benzoin compound, a hydroxy ketone compound, an amino ketone compound, a phosphine oxide compound, and a combination thereof. However, It is not particularly limited as long as it can be started.

For example, the photopolymerization initiator may be selected from benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethyl anino acetophenone, 2 , 2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy- Propane-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2- propyl) Ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-ethyl anthraquinone, 2- Quinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethylketal, p - dimethylamino benzoate (2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide But is not limited thereto.

The ultraviolet irradiation may be performed at a wavelength of about 100 nm to about 400 nm. By irradiating ultraviolet light at the wavelength within the above range, the effect of the polymerization initiation reaction can be easily realized in the photopolymerization reaction. The ultraviolet irradiation dose is not particularly limited as long as it is controlled to such an extent that sufficient curing can be achieved without impairing all properties, for example, an illuminance of about 50 mW / cm ² to about 1,000 mW / cm ² , / cm ² to about 1,000 mJ / cm ² may be.

The photopolymerization reaction can be conducted for about 10 minutes to about 4 hours. Since the reaction time is short by performing the photopolymerization reaction within the above-mentioned range of time, the productivity of the pressure-sensitive adhesive composition can be secured.

When the acrylic copolymer resin is formed by the thermal polymerization reaction, the reaction should proceed for about 6 hours to about 10 hours. As a result, the polymerization time is prolonged and a large amount of energy is consumed However, by performing a photopolymerization reaction, the reaction time can be shortened and the energy consumption can be minimized.

In the photopolymerization reaction, the process temperature may be about 25 캜 to about 40 캜. Since the polymerization temperature during the photopolymerization reaction is maintained relatively low as compared with the polymerization temperature during the thermal polymerization reaction, it is possible to control the reaction amount under the mild conditions by controlling the reaction heat and the reaction rate.

Generally, when a polymerization initiator containing a large amount of functional group-containing monomer is initiated, a large amount of heat is generated to cause stirring failure due to reaction congestion or viscosity increase. However, when the photopolymerization reaction is used, the exothermic temperature can be controlled effectively, Resin can be produced. Specifically, when the exothermic temperature is lower than about 0.5 ° C, the polymer having the target weight average molecular weight is not polymerized. When the temperature is more than about 10 ° C, gel reaction or side reaction may occur.

The method may further include the step of adding to the acrylic copolymer resin thus formed at least one additive selected from the group consisting of a crosslinking agent, a curing agent, a coupling agent, and a combination thereof.

The crosslinking agent improves the cohesive force of the solvent-type pressure-sensitive adhesive composition through the reaction with the polar functional group contained in the acrylic copolymer resin, imparts a crosslinking structure, and controls the adhesive property.

The type of the crosslinking agent is not particularly limited and a typical crosslinking agent such as a urethane crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, a polyisocyanate crosslinking agent and a metal chelate compound may be used. Among them, the use of a polyisocyanate crosslinking agent It is advantageous to improve the curing rate and the durability of the pressure-sensitive adhesive composition.

Examples of the urethane-based crosslinking agent include at least one selected from the group consisting of toluylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and triphenylmethane-4,4 ', 4 "-triisocyanate and the like ; Examples of the epoxy cross-linking agent include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'-tetraglycidylethylenediamine and glycerin diglycidyl ether ≪ RTI ID = 0.0 > and / or < / RTI > Examples of the aziridine crosslinking agent include N, N'-hexamethylene-1,6-bis (1-aziridine carboxamide) [HDU], N, N'- (2-methyl aziridine) and tri (N, N'-diphenylmethane-4,4'-bis -1-aziridinylphosphine oxide, and the like.

The diisocyanate used to form the polyisocyanate crosslinking agent may be selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, tetramethylxylyl diisocyanate, bis (4-isocyanatocyclohexyl) methane.

Examples of the metal chelate compound include compounds in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and / or vanadium is coordinated to acetylacetone or ethyl acetoacetate. But is not limited to.

The acrylic copolymer resin may further contain a curing agent. The curing agent is selected from the group consisting of amine-based curing agents, guanidine-based curing agents, imidazole curing agents, phenol-based curing agents, acid anhydride-based or isocyanate-based compounds, such as trilene diisocyanate, hexamethylene diisocyanate, isoform diisocyanate, xylene diisocyanate, At least one of isocyanate, diphenylmethane diisocyanate, water-added diphenylmethane diisocyanate, tetramethylxylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate or polymethylene polyphenyl isocyanate.

The acrylic copolymer resin may further include a coupling agent. The coupling agent improves the adhesiveness and adhesive stability of the solvent-type pressure-sensitive adhesive composition and can improve heat resistance and moisture resistance. In addition, the coupling agent can improve adhesion reliability when the pressure-sensitive adhesive composition is allowed to stand for a long time under high temperature or high humidity conditions.

Examples of the coupling agent include? -Glycidoxypropyltriethoxysilane,? -Glycidoxypropyltrimethoxysilane,? -Glycidoxypropylmethyldiethoxysilane,? -Glycidoxypropyltriethoxysilane , 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane,? -Methacryloxypropyltrimethoxysilane,? -Methacryloxypropyltriethoxysilane,? -Aminopropyltri Methoxy silane,? -Aminopropyltriethoxy silane, 3-isocyanatopropyl triethoxy silane,? -Acetoacetate propyl trimethoxy silane,? -Acetoacetate propyl triethoxy silane,? -Cyano acetyl Trimethoxysilane,? -Cyanoacetyltriethoxysilane, acetoxyacetotrimethoxysilane, and mixtures of one kind or more of the above can be used. In the present invention, it is preferable to use a silane-based coupling agent having an acetoacetate group or a? -Cyanoacetyl group, but the present invention is not limited thereto.

The additive may be included in an amount of about 0.02 part by weight to about 2.0 parts by weight based on 100 parts by weight of the acrylic copolymer resin. If the content of the additive is less than about 0.02 parts by weight, the cohesive strength and hardenability of the pressure-sensitive adhesive composition is low, and the heat resistance is deteriorated to make it difficult to use for a long period of time. If the content is more than about 2.0 parts by weight, .

In addition, the method for preparing the solvent-type pressure-sensitive adhesive composition may include a step of appropriately adding an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, a defoamer, a surfactant, a plasticizer and the like for general purposes for specific purposes.

Another embodiment of the present invention is a resin composition comprising an acrylic copolymer resin having a weight average molecular weight of 1,000,000 to 3,500,000, wherein the acrylic copolymer resin has a molecular weight distribution (PolyDispersity Index) of 1 to 5 or less, and the glass of the acrylic copolymer resin And a transition temperature of from -20 占 폚 to -45 占 폚.

The peel strength of the solvent-type pressure-sensitive adhesive composition may be about 1,700 g / in to about 2,400 g / in. The solvent-type pressure-sensitive adhesive composition was prepared by dissolving 15 parts by weight of the hydrophilic functional group-containing monomer in 100 parts by weight of the (meth) acrylic acid ester-based monomer, To 70 parts by weight of the polymerizable monomer, excellent adhesion can be secured.

If the content of the hydrophilic functional group-containing monomer in the solvent-type pressure-sensitive adhesive composition is too low, it may be difficult to ensure the desired durability of the solvent-type pressure-sensitive adhesive composition, so that the effect of the adhesive force may be insufficient. If the content of the monomer is too high, The process efficiency may be deteriorated and the defect rate for the adhesive force may be increased.

The haze value of the solvent-type pressure-sensitive adhesive composition may be about 0.1% to about 0.5%. When the conventional pressure sensitive adhesive composition is exposed to a high temperature and high humidity environment for a long time, whitish appearance appears. The acrylic copolymer resin of the solvent type pressure sensitive adhesive composition is formed to contain a certain amount of the hydrophilic functional group containing monomer, It is possible to reduce the probability that the water is absorbed and the whitening phenomenon occurs.

Specifically, when the solvent-type pressure-sensitive adhesive composition is stored under constant temperature and humidity conditions of 85 ° C and 85% RH for 7 days, and the haze value is evaluated, the whitening phenomenon can be prevented while maintaining the haze value in the above range.

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

< Example  And Comparative Example >

Example  One

(3-L) reactor equipped with a cooling device for reflux of nitrogen gas and easy temperature control was charged with 17.64 parts by weight of 2-hydroxyethyl acrylate (2-HEA) monomer per 100 parts by weight of ethylhexyl acrylate Ethyl acetate (EAc) was added as an organic solvent for polymerization reaction with the monomer and stirred to prepare a first mixed solution.

The stirring was continued and the temperature of the first mixed solution was raised to 30 DEG C while dissolved oxygen in the first mixed solution was removed for 30 minutes. At this time, the temperature of the first mixed solution was maintained at 30 ° C., and a photopolymerization initiator prepared by dissolving in a small amount of ethylacetate was added to the reactor to prepare a second mixed solution. The polymerization reaction was conducted by irradiating ultraviolet rays of 360 nm wavelength To thereby form an acrylic copolymer resin.

0.2 parts by weight of a HDI-based curing agent MHG-80B (Asahi Kasei) and a silane-based coupling agent (KBM 403, ShinEtsu) were added in an amount of 0.3 parts by weight based on 100 parts by weight of the acrylic copolymer resin, And this was diluted with a solvent to prepare a coating solution. The prepared coating solution was coated on a release-treated polyethylene terephthalate (PET) film having a thickness of 75 탆, dried and coated to a thickness of about 50 탆. Thereafter, it was dried at 110 DEG C for 3 minutes to thermally cure, and then aged at 50 DEG C for 3 days to prepare a pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive layer.

Example 2

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that 100 parts by weight of EHA and 33.3 parts by weight of 2-HEA were added.

Example 3

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that 100 parts by weight of EHA and 66.67 parts by weight of 2-HEA were added.

Example 4

To the 3L reactor equipped with a cooling device for regulating the temperature of the nitrogen gas and facilitating the temperature control, 100 parts by weight of ethylhexyl acrylate (EHA) was added with a polymerization monomer containing 17.64 parts by weight of acrylic acid (AA) monomer and ethyl acetate EAc) was added and stirred to prepare a first mixed solution.

The stirring was continued and the temperature of the mixed solution was raised to 30 DEG C while the dissolved oxygen in the first mixed solution was removed for 30 minutes. At this time, the temperature of the mixed solution was maintained at 30 ° C., and a photopolymerization initiator prepared by dissolving in a small amount of ethylacetate was added to the reactor to prepare a second mixed solution. The polymerization reaction was carried out by irradiating with ultraviolet ray of 360 nm wavelength, To form a coalesced resin.

0.1 part by weight of an aziridine crosslinking agent (HDU, N, N'-hexamethylene-1,6-bis (10 aziridine carboxamide)) was added to 100 parts by weight of the acrylic copolymer resin to prepare a solvent type pressure- . Then, the prepared coating solution was coated on a release-treated polyethylene terephthalate (PET) film having a thickness of 75 μm and dried to coat the coating solution so that the thickness became 30 μm. Thereafter, the coating solution was dried at a temperature of 110 DEG C for 3 minutes, and aged at a temperature of 50 DEG C for 24 hours to prepare a pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive layer.

Example 5

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that 100 parts by weight of EHA and 33.3 parts by weight of AA were added.

Example 6

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that 100 parts by weight of EHA and 66.7 parts by weight of AA were added.

Comparative Example  One

The second mixed solution was introduced into a 2 L reactor equipped with a cooling device so that nitrogen gas was refluxed and the temperature thereof was easily controlled, and the polymerization reaction was carried out by applying heat at 65 ° C. A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that an acrylic copolymer resin was formed.

Comparative Example  2

The second mixed solution was introduced into a 2 L reactor equipped with a cooling device so that nitrogen gas was refluxed and the temperature thereof was easily controlled, and the polymerization reaction was carried out by applying heat at 65 ° C. A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 3, except that an acrylic copolymer resin was formed.

Comparative Example  3

The second mixed solution was introduced into a 2 L reactor equipped with a cooling device so that nitrogen gas was refluxed and the temperature thereof was easily controlled, and the polymerization reaction was carried out by applying heat at 65 ° C. A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 4, except that an acrylic copolymer resin was formed.

Comparative Example  4

The second mixed solution was introduced into a 2 L reactor equipped with a cooling device so that nitrogen gas was refluxed and the temperature thereof was easily controlled, and the polymerization reaction was carried out by applying heat at 65 ° C. A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 6 except that an acrylic copolymer resin was formed.

Comparative Example  5

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that 100 parts by weight of EHA and 5.263 parts by weight of 2-HEA were added.

Comparative Example  6

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that 100 parts by weight of EHA and 80 parts by weight of 2-HEA were added.

Polymerization method Monomer composition ratio Polymerization stability Example 1 Light curing EHA (100) HEA (17.64) O Example 2 Light curing EHA (100) HEA (33.3) O Example 3 Light curing EHA (100) HEA (66.67) O Example 4 Light curing EHA (100) AA (17.64) O Example 5 Light curing EHA (100) AA (33.3) O Example 6 Light curing EHA (100) AA (66.67) O Comparative Example 1 Thermal polymerization EHA (100) HEA (17.64) X Comparative Example 2 Thermal polymerization EHA (100) HEA (66.67) X Comparative Example 3 Thermal polymerization EHA (100) AA (17.64) X Comparative Example 4 Thermal polymerization EHA (100) AA (66.67) X Comparative Example 5 Light curing EHA (100) HEA (5.263) △ Comparative Example 6 Light curing EHA (100) HEA (80) X

O: High polymerization reaction stability,?: Polymerization reaction stability Usually, X: Low polymerization reaction stability

< Experimental Example - Physical properties of solvent-type pressure-sensitive adhesive composition

1) Measurement of Weight Average Molecular Weight and Weight Average Molecular Weight Distribution: A gel permeation chromatograph (Agilient) was used to measure the rate of 1.0 minute by using tetrahydrofuran as a solvent. The calibration curve was compared with a calibration curve of a polystyrene standard sample, EXAMPLES AND COMPARATIVE EXAMPLES The weight average molecular weight and the weight average molecular weight distribution of the acrylic copolymer resin were measured.

2) Conversion rate: The difference between the theoretical solid concentration of the acrylic copolymer resin and the solid content concentration measured in the actual experiment when the added polymerizable monomer was converted into the 100% acrylic copolymer resin was expressed as a percentage, The conversion rate was calculated.

[General formula]

Conversion ratio (%) = {(measured solid content concentration) / (theoretical solid concentration)} X100

3) Measurement of gel content: The pressure-sensitive adhesive sheets of the examples and comparative examples were stored in a constant temperature and humidity room (23 DEG C, 60% RH) for about 7 days. Next, 0.3 g of the solvent-type pressure-sensitive adhesive composition was collected from the pressure-sensitive adhesive sheet, placed in a stainless steel 200 mesh wire net, immersed in 100 ml of ethyl acetate, and stored in a dark room at room temperature for 48 hours.

Subsequently, after the insoluble fractions were separated, the insoluble minute adhesive composition was dried in an oven at 120 ° C. for 4 hours, and its dry mass was measured. Thereafter, the measurement results of the respective masses were substituted into the following <Formula 1>, and the gel content was measured.

&Lt; General Formula 1 > Gel content (%) = B / AX100

A: The mass of the pressure-sensitive adhesive composition collected from the pressure-sensitive adhesive sheet

B: The pressure-sensitive adhesive composition was immersed in ethyl acetate at room temperature for 48 hours, and insoluble fractions were collected. Ethyl acetate was removed from the insolublesensitive adhesive composition and the dry mass

4) Peeling force measurement: The above-mentioned Examples and Comparative Examples were attached to the glass surface at a rate of 300 / min and peel strength was measured while peeling off after 30 minutes.

5) Evaluation of durability: The PET film was removed from the pressure sensitive adhesive sheet prepared in Examples and Comparative Examples, a hard coated surface of a polycarbonate (PC) film was attached to one side of the pressure sensitive adhesive layer, (PET film ITO side / pressure-sensitive adhesive layer / PC film hard coated side) was prepared by adhering and pressing the ITO side of the PET film having the ITO layer formed on one side thereof. Thereafter, the specimens were stored for 7 days under constant temperature and humidity conditions of 85 ° C and 85% RH, and the degree of opacity was visually observed and evaluated according to the following criteria.

6) Evaluation of peel strength: The pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples were cut to a size of 25 mm x 20 cm (width x length) to prepare specimens. Thereafter, one surface of the specimen was reciprocated five times with a 2 kg roller on a glass substrate surface, and after 30 minutes passed, the specimen was subjected to a tensile tester at a peel rate of 300 mm / min and a peel angle of 180 The peeling force was measured.

7) Measurement of HAZE (%): The PET film was removed from the pressure-sensitive adhesive sheet prepared in Examples and Comparative Examples, and one side of the pressure-sensitive adhesive layer was attached to the glass surface. Day, the haze value was measured based on ASTM D1003.

Mw Conversion Rate (%) PDI Gel (%) Peel force (g / in) Haze value
(%) Presence or absence of cloudiness
(7 days later) Example 1 103 million 91 3 82 1750 0.5 O Example 2 1.1 million 91 3 83 2040 0.4 O Example 3 1 million 92 2.8 81 1900 0.2 O Example 4 147 million 93 3.5 80 2200 0.4 O Example 5 1.7 million 91 2.7 84 2000 0.3 O Example 6 2.3 million 90 3 82 2380 0.1 O Comparative Example 1 98 million 87 8 85 1530 0.7 X Comparative Example 2 95 million 89 8.5 88 1650 0.8 X Comparative Example 3 87 million 90 10 86 1690 0.6 X Comparative Example 4 89 million 91 8.9 87 1500 0.6 X Comparative Example 5 1 million 92 7.2 88 980 1.0 X Comparative Example 6 99 million 91 8 89 1200 0.6 X

O: no cloudiness observed, X: cloudiness observed

The results are shown in Table 2. Referring to Table 2, it was found that Examples 1 to 6 were more excellent in polymerization reaction stability than Comparative Examples 1 to 4 in producing an acrylic copolymer resin, and Examples 1 to 6 When the haze value was measured to be significantly less than that of the comparative example, no cloudiness was observed, whereas in Comparative Examples 1 to 4, cloudiness was observed.

The acrylic copolymer resins of Examples 1 to 5 had a weight average molecular weight of 1,000,000 or more and a high molecular weight relative to the weight average molecular weight of the acrylic copolymer resin of Comparative Examples 1 to 4 and a weight average molecular weight distribution (PDI) of 5 or less Respectively.

On the other hand, Comparative Example 5 contained less than 15 parts by weight of hydrophilic functional group-containing monomer and contained more than 70 parts by weight of Comparative Example 6, and Comparative Example 6 was formed by photopolymerization. In Comparative Example 6, however, , And Comparative Example 5 was found to have cloudiness due to an increase in haze value because the content of hydrophilic was small. It was thus found that the content of the hydrophilic functional group-containing monomer had a significant influence on polymerization stability and opacity.

Claims (17)

Preparing a first mixed solution comprising a polymerization monomer containing 15 to 70 parts by weight of a hydrophilic functional group-containing monomer per 100 parts by weight of the (meth) acrylic acid ester monomer and an organic solvent for polymerization;
Adding a photopolymerization initiator to the first mixed solution to prepare a second mixed solution; And
And irradiating ultraviolet light to the second mixed solution to initiate a photopolymerization reaction to form an acrylic copolymer resin,
The photopolymerization reaction is carried out at 25 to 40 ° C for 10 minutes to 4 hours, and the photopolymerization reaction is carried out at a temperature of 0.5 to 10 ° C
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
Wherein the conversion ratio of the polymerization monomer to the acrylic copolymer resin is 70% or more
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
The acrylic copolymer resin produced by the method for producing a solvent-type pressure-sensitive adhesive composition has a weight average molecular weight of 1 million to 3,000,000
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
The acrylic copolymer resin produced by the method for producing a solvent-type pressure-sensitive adhesive composition has a weight average molecular weight distribution (PolyDispersity Index) of 1 to 5
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
Wherein the acrylic copolymer resin produced by the method for producing a solvent-type pressure-sensitive adhesive composition has a glass transition temperature of -20 占 폚 or lower
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
The (meth) acrylate monomer may be at least one selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (Meth) acrylate, isononyl (meth) acrylate, isononyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Ethylbutyl (meth) acrylate, and combinations thereof.
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
Wherein the hydrophilic functional group-containing monomer is at least one selected from the group consisting of a hydroxyl group-containing monomer, an amino group-containing monomer, a carboxyl group-containing monomer, a sulfonic group-containing monomer, a morpholin group-containing monomer and a glycidyl group-
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
The organic solvent for polymerization is added in an amount of 10 to 900 parts by weight per 100 parts by weight of the polymerizable monomer
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
The organic solvent for polymerization may be at least one selected from the group consisting of ethyl ether, acetone, acetonitrile, petroleum ether, isopropyl alcohol, methanol, ethanol, n-pentane, n-hexane, benzene, dichloromethane, trichloromethane, methyl acetate, At least one selected from the group consisting of glycol dimethyl ether, methyl ethyl ketone, trichloromethane, tetrachloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, n-hexane, cyclohexane,
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
The photopolymerization initiator is added in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the polymerization monomer
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
Wherein the photopolymerization initiator is at least one selected from the group consisting of a benzoin compound, a hydroxy ketone compound, an amino ketone compound, a phosphine oxide compound,
A method for producing a solvent-type pressure-sensitive adhesive composition.
The method according to claim 1,
The ultraviolet ray irradiation is performed at a wavelength of 100 nm to 400 nm
A method for producing a solvent-type pressure-sensitive adhesive composition.
delete The method according to claim 1,
Further comprising adding 0.02 part by weight to 2.0 parts by weight of at least one additive selected from the group consisting of a crosslinking agent, a curing agent, a coupling agent and a combination thereof to 100 parts by weight of the acrylic copolymer resin
A method for producing a solvent-type pressure-sensitive adhesive composition.
And an acrylic copolymer resin having a weight average molecular weight of 1,000,000 to 3,500,000, wherein the acrylic copolymer resin has a molecular weight distribution (PolyDispersity Index) of 1 to 5 or less, and the acrylic copolymer resin has a glass transition temperature of -20 占 폚 to -45 &lt;
A process for the preparation of
Solvent type pressure-sensitive adhesive composition.
16. The method of claim 15,
Wherein the solvent-type pressure-sensitive adhesive composition has a peel strength of 1,700 g / in to 2,400 g / in
Solvent type pressure-sensitive adhesive composition.
16. The method of claim 15,
Wherein the solvent-type pressure-sensitive adhesive composition has a haze value of 0.1% to 0.5%
Solvent type pressure-sensitive adhesive composition.