TW201510146A - Adhesive composition - Google Patents

Abstract

Provided is an adhesive composition, including: an acryl-based copolymer prepared by copolymerizing monomers including 1 to 10 parts by weight of a (meth)acrylate-based monomer having a carboxyl group and 0.1 to 2 parts by weight of a (meth)acrylate-based monomer having a linear or cyclic alkyl group with 4 or more carbon atoms substituted with a hydroxyl group, based on 100 parts by weight of all monomers; a trifunctional or higher tolylene diisocyanate-based cross-linking agent; and an ionic anti-static agent having a Na<SP>+</SP> or K<SP>+</SP> ion, so that the adhesive composition can improve anti-static property and durability at the same time, have no fear of deterioration in physical properties due to change over time (change in high temperature or high temperature and high humidity environment), and shorten the curing period.

Description

Adhesive composition

The present invention relates to an adhesive composition which has good antistatic properties and liquid stability and a short curing period.

In general, a liquid crystal display (LCD) includes a polarizing plate and a liquid crystal cell having a liquid crystal, wherein an adhesive layer suitable for bonding the liquid crystal cell to the polarizing plate is used. For the adhesive, an acrylic adhesive comprising an acrylic polymer having good adhesion and transparency as a base material is widely used.

During the process of bonding the polarizing plate to the liquid crystal cell, the release film is peeled off from the adhesive layer to cause static electricity. Static electricity can affect the alignment of the liquid crystal, cause liquid crystal defects, or induce electrostatic attraction, so that the foreign matter flows into the liquid crystal cell and the adhesive to cause contamination.

In order to solve those problems, an ionic antistatic agent is mixed with an adhesive composition. However, the appearance of bleed due to the migration of the ionic antistatic agent to the surface causes curling, foaming, delamination, and the like. More specifically, those defects may be more severe at high temperatures or high temperatures.

Meanwhile, conventionally, an adhesive composition comprising an acrylic copolymer obtained by copolymerization of an oxyalkylene-containing monomer has been disclosed [Korean Patent Publication Nos. 2012-0073093 and 2009-0055576]. However, it may As the time increases, the viscosity of the acrylic copolymer increases, so that the acrylic copolymer is difficult to store in mass production.

In addition, in addition to antistatic properties and durability, the adhesive composition also plays an important factor influencing productivity during curing, and more specifically, it can affect storage capacity, inventory management, and emergency shipment processing. , and the like.

Therefore, conventionally, various catalysts which can increase the crosslinking reaction rate to shorten the curing period have been described [Korean Patent Publication Nos. 2012-0091549 and 2010-0039274]. However, it is important to control the amount of catalyst used in the crosslinking reaction. More specifically, if too much catalyst is added, the risk of equipment clogging or the like will result.

The present invention solves the above problems that have occurred in the prior art, and an object of the present invention is to provide an adhesive composition which can improve antistatic properties and durability while not increasing the viscosity over time. The curing period is shortened without using a crosslinking catalyst.

According to an object of the present invention, there is provided an adhesive composition comprising: an acrylic copolymer comprising 1 to 10 parts by weight of a carboxyl group on the basis of 100 parts by weight of all monomers ( a methyl acrylate monomer and 0.1 to 2 parts by weight of a monomer having a (meth) acrylate monomer having a linear or cyclic alkyl group substituted with 4 or more carbon atoms by a hydroxyl group; Preparation; a trifunctional or higher toluene diisocyanate crosslinking agent; and an ionic antistatic agent having Na ⁺ or K ⁺ ions.

The (meth) acrylate monomer having a linear or cyclic alkyl group having a hydroxyl group substituted with 4 or more carbon atoms may be at least one selected from the group consisting of 4-hydroxybutyl acrylate and 6-hydroxyhexyl group (A) Acrylate, octyl 8-hydroxy(meth)acrylate, and The group formed.

The monomer for preparing the acrylic copolymer may further comprise a (meth) acrylate monomer having an aromatic ring.

The antistatic agent can be a fluorine-containing anion.

The fluorine-containing anion can be OTF ( ), TFSI ( ), or FSI ( ).

The acrylic copolymer may comprise (1) 88 to 98 parts by weight of an alkyl (meth) acrylate monomer having 1 to 12 carbon atoms, based on 100 parts by weight of all monomers. 2) 1 to 10 parts by weight of a (meth) acrylate monomer having a carboxy group; and 3) 0.1 to 2 parts by weight of a linear or cyclic alkyl group having 4 or more carbon atoms substituted with a hydroxy group The monomer of the (meth) acrylate monomer is copolymerized to prepare.

The adhesive composition may comprise 0.1 to 1 part by weight of a trifunctional or higher toluene diisocyanate crosslinking agent, and 0.5 to 5 parts by weight of Na, based on 100 parts by weight of the acrylic copolymer. ⁺ or K ⁺ ion ionic antistatic agent.

During the curing of the adhesive composition, it may be 48 hours or less at a time point based on 23 ° C and 65% RH not changing with time, and the adhesive composition is placed before room temperature for 24 hours. The subsequent viscosity change can be 50% or less.

The present invention discloses an adhesive composition which has good antistatic properties and liquid stability and a short curing period.

Next, the details of the present invention will be described below.

The adhesive composition of the present invention comprises: an acrylic copolymer comprising 1 to 10 parts by weight of a (meth) acrylate monomer having a carboxyl group, based on 100 parts by weight of all monomers. And 0.1 to 2 parts by weight of a monomer having a (meth) acrylate monomer having a linear or cyclic alkyl group substituted with 4 or more carbon atoms by a hydroxyl group; a trifunctional group or higher; a toluene diisocyanate crosslinking agent; and an ionic antistatic agent having Na ⁺ or K ⁺ ions.

The (meth) acrylate monomer having a monocarboxy group suppresses the occurrence of bleed out due to the migration of the ionic antistatic agent to the surface, and improves the durability by enhancing the adhesion to the glass. The (meth) acrylate monomer having a monohydroxy group can shorten the curing period of the adhesive composition by increasing the crosslinking reaction.

Further, the Na+ or K+ ions of the ionic antistatic agent form a coordinate bond with the hydroxyl group, thereby suppressing the reaction of the hydroxyl group and the isocyanate, thereby improving the liquid stability of the adhesive composition.

Further, the trifunctional or higher toluene diisocyanate crosslinking agent is an aromatic isocyanate which has good reactivity with a (meth) acrylate monomer having a monohydroxy group, thereby shortening the adhesive composition. During the curing of the object.

In other words, the present invention is characterized in that a (meth) acrylate monomer having a carboxyl group and a (meth) acrylate having a linear or cyclic alkyl group having a hydroxyl group substituted by four or more carbon atoms The monomer is contained in a monomer for preparing an acrylic copolymer; a trifunctional or higher toluene diisocyanate crosslinking agent and an ionic antistatic agent having Na ⁺ and K ⁺ ions are used; The monomer used to prepare the acrylic copolymer also adopts an optimum mixing ratio to simultaneously improve antistatic properties, durability, curing time, and liquid stability.

The acrylic copolymer of the present invention is preferably a (meth) acrylate comprising: 88 to 98 parts by weight of an alkyl group having 1 to 12 carbon atoms, based on 100 parts by weight of all monomers. a monomer; 1 to 10 parts by weight of a (meth) acrylate monomer having a carboxy group; and 0.1 to 2 parts by weight of a linear or cyclic alkyl group having a hydroxyl group substituted with 4 or more carbon atoms ( A monomer of a methyl acrylate monomer is copolymerized to prepare.

Examples of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms are methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (methyl). Butyl acrylate, butyl n-(meth)acrylate, butyl 2-(meth)acrylate, butyl t-(meth)acrylate, ethylhexyl 2-(meth)acrylate, (methyl) Ethyl acrylate, propyl n-(meth)acrylate, isopropyl (meth)acrylate, amyl (meth)acrylate, octyl n-(meth)acrylate, isooctyl (meth)acrylate, Bismuth (meth)acrylate Ester, decyl (meth) acrylate, lauryl (meth) acrylate, and the like. Among them, n-butyl acrylate, ethyl hexyl acrylate, or a mixture thereof is preferred. They may be used singly or in combination of two or more.

The (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms may be contained in an amount of from 88 to 98 parts by weight based on 100 parts by weight of all the monomers. If the (meth) acrylate monomer is less than 88 parts by weight, the adhesion will be insufficient, but if it exceeds 98 parts by weight, the cohesive force will be lowered.

As the (meth) acrylate monomer having a monocarboxy group, acrylic acid or methacrylic acid can be used.

The content of the (meth) acrylate monomer having a monocarboxy group is preferably from 1 to 10 parts by weight based on 100 parts by weight of all the monomers. If the content is less than 1 part by weight, the effect of suppressing the bleeding of the ionic antistatic agent will be small, the durability will be deteriorated, or the effect as a catalyst for the crosslinking reaction will be weak, resulting in failure to be shortened during curing. If the content exceeds 10 parts by weight, the liquid stability of the adhesive composition may be deteriorated due to excessive crosslinking reaction.

The (meth) acrylate monomer having a linear or cyclic alkyl group having a hydroxyl group substituted with 4 or more carbon atoms may be at least one selected from the group consisting of 4-hydroxybutyl (meth) acrylate, 6- Hydroxyhexyl (meth) acrylate, 8-hydroxy (meth) acrylate, and The group formed. Considering the curing period, preferably 4-hydroxybutyl acrylate or .

The content of the (meth) acrylate monomer having a linear or cyclic alkyl group having 4 or more carbon atoms substituted with a hydroxyl group is preferably 0.1 to 100 parts by weight based on all monomers. 2 parts by weight. If the content is less than 0.1 parts by weight, it may be slightly shortened during curing. If the content exceeds 2 parts by weight, the liquid stability of the adhesive composition may be deteriorated due to excessive crosslinking reaction.

Further, in order to prevent light leakage, the monomer for producing an acrylic copolymer of the present invention may further comprise a (meth) acrylate monomer having an aromatic ring group.

Examples of the (meth) acrylate monomer having an aromatic ring group may be at least one selected from the group consisting of 2-ethylphenoxy (meth) acrylate, 2-ethyl thiophenyl (meth) acrylate, Phenyl (meth) acrylate, benzyl (meth) acrylate, ethyl 2-phenyl (meth) acrylate, propyl 3-phenyl (meth) acrylate, 4-phenyl (methyl) Butyl acrylate, ethyl 2-methylphenyl (meth)acrylate, ethyl 2-2-3-phenylphenyl (meth)acrylate, 2-4-methylphenyl (meth)acrylate Ester, ethyl 2-(4-propylphenyl)(meth)acrylate, ethyl 2-(4-(1-methylethyl)phenyl)(meth)acrylate, 2-(4-A Ethyl phenyl)ethyl (meth)acrylate, ethyl 2-(4-cyclohexylphenyl)(meth)acrylate, ethyl 2-(2-chlorophenyl)(meth)acrylate, 2-( 3-chlorobenzene)ethyl (meth)acrylate, ethyl 2-(4-chlorophenyl)(meth)acrylate, ethyl 2-(4-bromophenyl)(meth)acrylate, 2-(3- A group consisting of phenylbenzene)ethyl (meth)acrylate and ethyl 2-(4-benzylphenyl)(meth)acrylate. In view of copolymerization reactivity, 2-ethylphenoxy (meth) acrylate or benzyl (meth) acrylate is preferred.

a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms, a (meth) acrylate monomer having a carboxyl group, and having 4 groups substituted with a hydroxyl group When the (meth) acrylate monomer having a linear or cyclic alkyl group of a plurality of carbon atoms is 100 parts by weight, the content of the (meth) acrylate monomer having an aromatic ring group is preferably 6 Up to 12 parts by weight. If it is added in an amount of less than 6 parts by weight or more than 12 parts by weight, light leakage will occur.

The preparation method of the copolymer is not particularly limited. The copolymer can be prepared by conventional methods such as bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization. Among them, solution polymerization is preferred. Further, a solvent commonly used in conventional polymerization, a polymerization initiator, a chain transfer agent for controlling molecular weight, and the like can also be used.

The weight average molecular weight of the copolymer (in terms of polystyrene, Mw), measured by colloidal permeation chromatography, is from 50,000 to 2,000,000, and preferably from 400,000 to 2,000,000. If the weight average molecular weight of the copolymer is less than 50,000, the cohesive force with the copolymer will be insufficient, resulting in a problem of adhesion durability. If the weight average molecular weight of the copolymer exceeds 200,000, a large amount of a diluent solvent is required for coating to ensure processability.

The cross-linking agent improves adhesion and durability, maintains reliability at high temperatures, and retains the shape of the adhesive. More specifically, it is considered to be a (meth) acrylate monomer having a monocarboxy group and a (meth) acrylate having a linear or cyclic alkyl group having a hydroxyl group substituted by four or more carbon atoms. As the reactivity, durability, and light leakage prevention of the monomer, a trifunctional or higher toluene diisocyanate crosslinking agent is preferably used.

Examples of the trifunctional or higher toluene diisocyanate crosslinking agent are toluene diisocyanate (Urethane Co., Ltd., Japan, CORONATE-L) trimethylolpropane adduct and toluene diisocyanate tripolymer (Aekyung Chemical Co., Ltd.) Division, AKNATE TR-50).

The trifunctional or higher toluene diisocyanate crosslinking agent may be included in an amount of 0.1 to 1 part by weight based on 100 parts by weight of all the monomers. If the content is less than 0.1 part by weight, the degree of crosslinking will be insufficient, resulting in a decrease in cohesive force, resulting in deterioration in durability such as peeling and weaken cuttability. If the content exceeds 1.0 part by weight, it will be difficult to ensure the stability of the liquid.

In order to improve liquid stability, the present invention may comprise an ionic antistatic agent having Na ⁺ and K ⁺ ions which reduces the reaction rate of a hydroxyl group and an isocyanate group in the acrylic copolymer.

As the anion of the ionic antistatic agent, a fluorine-containing anion or an iodide ion can be used. The fluorine-containing anion can be trifluoromethanesulfonic acid ( ), bis(trifluorosulfonyl)imide ( And bis(fluorosulfonyl)imide ( ).

The ionic antistatic agent is contained in an amount of from 0.5 to 5 parts by weight based on 100 parts by weight of the acrylic copolymer. If the content of the ionic antistatic agent is less than 0.5 part by weight, the antistatic property is insufficient, and if the content of the ionic antistatic agent exceeds 5 parts by weight, the durability cannot be maintained.

Further, the adhesive composition of the present invention may further comprise a decane coupling agent.

The kind of the decane coupling agent is not particularly limited. Examples of the decane coupling agent are vinyl chlorodecane, vinyl trimethoxy decane, vinyl triethoxy decane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxy decane, 3-ring Oxypropoxy Propyltrimethoxydecane, 3-glycidoxypropylmethyldiethoxydecane, 3-glycidoxypropylmethyldiethoxydecane, 3-glycidoxypropyl Triethoxydecane, p-styryltrimethoxydecane, 3-methacryloxypropyltriethoxydecane, 3-methacryloxypropyltrimethoxydecane, 3-methyl Acryloxymethyldimethoxydecane, 3-methacryloxypropylmethyldiethoxydecane, 3-acryloyloxypropyltrimethoxydecane, N-2-(aminoethyl) 3-aminopropylmethyldimethoxydecane, N-2-(aminoethyl)-3-aminopropyltrimethoxydecane, N-2-(aminoethyl)-3-aminopropyl Triethoxy decane, 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 3-triethoxymethylidene-N-(1,3-dimethyl-arylene , propylamine, N-phenyl-3-aminopropyltrimethoxydecane, 3-chloropropyltrimethoxydecane, 3-mercaptopropylmethyldimethoxydecane, 3-mercaptopropyltrimethoxy Decane, bis(triethoxymethanepropylpropyl) tetrasulfide, 3-isocyanate propyl triethoxy decane, and . They may be used singly or in combination of two or more.

The adhesive composition may further comprise, in addition to the above composition, an adduct such as a tackifier resin, an antioxidant, a leveling agent, a surface lubricant, a dye, a pigment, an antifoaming agent, a filler, and a light stabilizer to control adhesion. Force, cohesion, viscosity, modulus of elasticity, glass transition temperature, and the like.

The content of the additive can be appropriately controlled within a range that does not deteriorate the effect of the present invention.

The adhesive composition of the present invention can be used as an adhesive for bonding a polarizing plate to a liquid crystal cell or an adhesive for a surface protective film. Further, the adhesive composition of the present invention can be used for a protective film, a reflective sheet, an adhesive sheet for molding, and used for Photographic adhesive sheets, adhesive sheets for marking land, adhesives for optical adhesive products, and electronic products, and adhesive sheet products for general advertising products.

The preferred embodiments are provided to aid in the understanding of the present invention, and the following examples are merely illustrative of the invention and are not intended to limit the invention. The scope of the present invention is defined by the scope of the appended claims, unless otherwise claimed.

Preparation example: acrylic copolymer

Preparation Examples 1 to 11 and Comparative Preparation Examples 1 to 5

The monomer mixture prepared according to the composition shown in Table 1 was placed in a 1 liter reactor equipped with a cooling device to promote nitrogen reflux and temperature control, and then 100 parts by weight of ethyl acetate was added as a solvent. among them. After that, it was purged with nitrogen for 1 hour to remove oxygen, and the temperature was maintained at 78 °C. Stir the mixture evenly. Then, 0.03 part by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator, and a reaction was further carried out for 8 hours to prepare an acrylic copolymer having a weight average molecular weight of about 780,000.

Examples 1 to 18 and Comparative Examples 1 to 12

Each of the adhesive compositions having a solid content of 15% was prepared by mixing an acrylic copolymer, an ionic antistatic agent, and a crosslinking agent as shown in Table 2, and the mixture was diluted with ethyl acetate.

Each of the adhesive compositions prepared as above was applied onto a release film coated with a ruthenium release agent to have a thickness of 25 μm, followed by drying at 100 ° C for 1 minute. Thereby forming an adhesive layer. A separate release film is laminated thereon to produce an adhesive sheet.

The release film of the produced adhesive sheet was peeled off, and then the formed adhesive layer was laminated to a 185 μm-thick iodine-based polarizing plate by an adhesive treatment to produce an adhesive polarizing plate. The produced polarizing plate was stored under the conditions of 23 ° C and 60% RH.

Test case

The physical properties of the adhesive composition, the adhesive sheet, and the adhesive-attached polarizing plate obtained by the examples and the comparative examples were measured by the following methods, and the measurement results are reported in Table 3.

1. Storage stability (viscosity change, %)

The viscosity of the adhesive composition was measured using a viscometer (Brookfield LVDV-II+B type (rotor code 3, 30 rpm)) and the viscosity of the adhesive composition after standing at room temperature for 24 hours, and the viscosity was calculated. Change (△η).

<Evaluation criteria>

○: Δη<50%

△: 50% Δη<100%

×: 100% △η

2. During curing

When the prepared adhesive sheet was cured at 23 ° C and 65% RH for 1 to 10 days, the gel fraction was measured daily as described below. The number of days of curing is extended until the gel fraction is no longer increased, that is, the curing period is determined accordingly.

Approximately 0.25 g of the adhesive layer of the adhesive sheet was fixed to a 250-mesh wire mesh (100 mm X 100 mm), and the wire mesh was wrapped to prevent the gel from escaping therefrom. A precision balance was used to accurately measure the weight, and the wire mesh was immersed in an ethyl acetate solution for 3 days. The soaked wire mesh was taken out, then rinsed with a small amount of ethyl acetate solution, dried at 120 ° C for 24 hours, and then weighed. The measured weight is used to calculate the gel fraction by Equation 1. The gelation rate (%) = (CA) / was determined based on the calculated time when the gel fraction fell within the range of 70% to 80% and no change with time was observed: [Equation 1] (BA) x 100

Wherein in Equation 1, A is the weight (g) of the wire mesh; B is the weight of the adhesive layer fixed to the wire mesh (BA: weight of the adhesive layer, g); and C is after the wire mesh is soaked and dried Weight (CA: weight of gel resin, g)].

3. Durability (heat resistance, heat and humidity resistance)

The prepared polarizing plate with an adhesive was cut into a size of 90 mm × 170 mm to prepare a sample, and the release film was peeled off therefrom, and the polarizing plate was attached to both sides of the glass substrate (110 mm × 190 mm × 0.7 mm). The light absorption axes of the polarizing plates are made orthogonal to each other. Here, a pressure of 5 kg/cm ² was applied and carried out in a clean room to avoid generation of bubbles or foreign materials. In order to measure heat resistance, the sample was placed at a temperature of 80 ° C for 1000 hours, and then, whether or not foaming or peeling occurred was observed. In order to measure the heat and humidity resistance, the sample was placed under conditions of 60 ° C and 90% RH for 1000 hours, and it was observed whether foaming or peeling occurred. Here, the sample was placed at room temperature for 24 hours before the sample evaluation.

<Evaluation criteria>

◎: No bubbles or peeling:

○: The number of bubbles or peeling <5

△: 5 The number of bubbles or peeling <10

×:10 Number of bubbles or strips

4. Antistatic properties (surface resistivity, Ω / □)

After the release film was peeled off from the adhesive sheet, the surface resistance values of the three points were measured 10 times, and the measured values were averaged.

Here, surface resistance measurement was performed using a surface resistance analyzer (MCP-HT450/MITSUBISHI CHEMICAL), a probe (URS, UR100), and a probe inspection sheet (for URS, for UR 100).

As is apparent from Table 3, the curing period of the adhesive composition according to Examples 1 to 18 of the present invention was shortened to 12 to 36 hours, which simultaneously improved the antistatic property and durability as compared with the adhesive compositions of Comparative Examples 1 to 12. Sexuality, and not afraid of physical characteristics, deteriorates with time (changes in high temperature or high temperature and high humidity environment).

As described above, the adhesive composition of the present invention can simultaneously improve the antistatic property and durability without deteriorating the physical properties with time (change in high temperature or high temperature and high humidity environment).

Further, the adhesive composition according to the present invention is significantly shortened to a period of 48 hours or less, and preferably 36 hours or less, during curing. Therefore, it is possible to suppress the use of too many additives which are commonly used to shorten the curing period, thereby improving conventional problems such as clogging of the device and the like.

Claims (8)

An adhesive composition comprising: an acrylic copolymer, comprising 1 to 10 parts by weight of a (meth) acrylate monomer having a carboxyl group, based on 100 parts by weight of all monomers; 0.1 to 2 parts by weight of a monomer having a (meth) acrylate monomer having a linear or cyclic alkyl group substituted with 4 or more carbon atoms by a hydroxyl group; a trifunctional group or higher; a toluene diisocyanate crosslinking agent; and an ionic antistatic agent having Na ⁺ or K ⁺ ions. The adhesive composition according to claim 1, wherein the (meth) acrylate monomer having a linear or cyclic alkyl group having a hydroxyl group substituted with 4 or more carbon atoms is at least one selected Free 4-hydroxybutyl acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxy (meth) acrylate, and The group formed. The adhesive composition according to claim 1, wherein the monomer for preparing the acrylic copolymer further comprises a (meth) acrylate monomer having an aromatic ring. The adhesive composition of claim 1, wherein the antistatic agent is a fluorine-containing anion. The adhesive composition of claim 4, wherein the fluorine-containing anion is trifluoromethanesulfonic acid ( ), bis(trifluorosulfonyl)imide ( ) or bis(fluorosulfonyl)imide ( ). The adhesive composition according to claim 1, wherein the acrylic copolymer comprises, by weight of 100 parts by weight of all monomers, by containing: 1) 88 to 98 parts by weight having 1 to 12 a (meth) acrylate monomer having an alkyl group of carbon atoms; 2) 1 to 10 parts by weight of a (meth) acrylate monomer having a carboxy group; and 3) 0.1 to 2 parts by weight having a hydroxyl group A monomer which replaces a linear or cyclic alkyl (meth) acrylate monomer having 4 or more carbon atoms is copolymerized to prepare. The adhesive composition according to claim 1, comprising 0.1 to 1 part by weight of a trifunctional or higher toluene diisocyanate crosslinking agent based on 100 parts by weight of the acrylic copolymer. And 0.5 to 5 parts by weight of an ionic antistatic agent having Na ⁺ or K ⁺ ions. The adhesive composition according to claim 1, wherein during the curing of the adhesive composition, it is 48 hours or less at a time point based on 23 ° C and 65% RH not changing with time. And the adhesive composition had a viscosity change of 50% or less before and after being left at room temperature for 24 hours.