KR100886677B1 - Acrylic adhesive composition and adhesive commodities containing the same - Google Patents

Abstract

The present invention is an acrylic adhesive resin: petroleum resin tackifier; And it provides an acrylic pressure-sensitive adhesive composition and a pressure-sensitive adhesive article comprising the thermally expandable filler.

The acrylic pressure-sensitive adhesive composition according to the present invention by using a petroleum resin-based tackifier is strengthened the initial adhesive strength and the adhesive holding power of the pressure-sensitive adhesive in the case of the aqueous acrylic pressure-sensitive adhesive is also easy to desorption after use by including a heat-expandable filler Has an advantage.

Acrylic adhesive resin, petroleum resin tackifier, thermally expandable filler, initial adhesion. Adhesion, water resistance, desorption

Description

Acrylic pressure-sensitive adhesive composition and pressure-sensitive adhesive article comprising the same {Acrylic adhesive composition and adhesive commodities containing the same}

1 is a schematic diagram showing a desorption process of the pressure-sensitive adhesive tape according to an embodiment of the present invention.

2 is a process chart showing a manufacturing process of the pressure-sensitive adhesive tape according to an embodiment of the present invention.

The present invention relates to an acrylic pressure-sensitive adhesive composition and a pressure-sensitive adhesive article including the same, and more particularly, to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive article having excellent initial adhesive force and pressure-sensitive adhesive force, excellent water resistance, and easy desorption after use.

Masking tapes, which are currently used for deadner application in the paint line of automobiles, have a predetermined size of holes therein to prevent application and protection. However, after passing through the firing line after the deadner spraying operation, the workers have to manually detach the masking process.In this process, the masking tape is not easy to be removed and defects such as adhesive residue may occur after the work. There is.

In addition, with the recent development of the IT industry, various electric and electronic products including displays are composed of various materials such as metals, ceramics, and plastics. Various adhesives are used to make this possible. In particular, in recent years, as electronic products have become slimmer, electronic components used therein tend to be more compact, and thus, necessity of an adhesive having excellent adhesive force to attach it is increasing. If the product is assembled incorrectly during the process and needs to be detached between parts, it needs to be removed without damaging the parts. Also in the pressure-sensitive adhesive itself, it is required to have characteristics such as heat insulation, insulation, thermal conductivity, electrical conductivity, electromagnetic shielding, durability and water resistance, oil resistance.

As a conventional technique relating to a detachable adhesive, a technique relating to an adhesive containing a foaming agent is described in Japanese Patent Laid-Open No. 5-279636 for ease of peeling. In the above patent, the adhesive contains a foaming agent so that the foaming agent is foamed by heating so that the substrates adhered by the adhesive can be easily separated.

Moreover, the adhesive using the side chain crystallization polymer (Japanese Patent Laid-Open No. 9-249858, etc.), the adhesive using a heat-curable compound (Japanese Patent Laid-Open No. 10-25456, etc.), and the like are also known. The pressure sensitive adhesive described in Japanese Patent Application Laid-Open No. 9-249858 contains a polymer that is branched and crystallized at a temperature of about 15 ° C. or lower so that the pressure-sensitive adhesive force is reduced to facilitate peeling, and the pressure-sensitive adhesive described in Japanese Unexamined Patent Publication No. 10-25456 The pressure-sensitive adhesive is characterized in that the adhesive force is reduced by curing the pressure-sensitive adhesive by heating about 50 to 150 ℃. However, all of the pressure-sensitive adhesives have a problem that peeling occurs at a relatively low temperature, and in particular, pressure-sensitive adhesives containing a thermosetting compound have a problem of high adhesive cost and low adhesive strength during use in the case of electronic products that generate heat.

In addition, Japanese Patent Laid-Open No. 10-316953 discloses a thermally conductive pressure-sensitive adhesive that adds a plasticizer having a boiling point of 150 ° C. or higher and exhibits high adhesion when using the pressure-sensitive adhesive but exhibits peelability after use of the pressure-sensitive adhesive. However, in the case of the pressure-sensitive adhesive, there is a problem that the adhesive force may be lowered because the plasticizer is included.

In addition, Korean Patent Laid-Open Publication No. 2003-0060736 discloses a method to facilitate desorption after use by including a compound that can expand by heat in an adhesive, but is not suitable for use where a high initial adhesive force is required, such as a small electronic product. There is a problem that the adhesive strength is insufficient, especially in the case of the water-based pressure-sensitive adhesive.

Therefore, not only the adhesive force is excellent in the use environment of the adhesive tape and the properties such as durability and water resistance, but also after use, it is easily detached from the used products such as the surface of automobiles and electronics where the adhesive article is used, and the residue of the adhesive There is a great need for development of a pressure-sensitive adhesive composition that does not leave.

The present invention is to achieve the above object, the first technical problem of the present invention is not only excellent in the initial adhesive strength, adhesive holding force and re-adhesive force, but also excellent in water resistance, and easy to remove after use to leave residue on the surface of the product used It is to provide an acrylic pressure-sensitive adhesive composition.

The second technical problem of the present invention is to provide an adhesive article such as an adhesive tape and an adhesive film including the acrylic adhesive composition.

The above and other objects of the present invention can be achieved by the present invention described below.

The present invention to achieve the first technical problem

Acrylic pressure-sensitive adhesive resins; Petroleum resin tackifiers; And it provides an acrylic pressure-sensitive adhesive composition comprising a thermally expandable filler.

The present invention to achieve the second technical problem

It provides an adhesive article comprising the acrylic pressure-sensitive adhesive composition.

When using a pressure-sensitive adhesive article such as pressure-sensitive adhesive tape, pressure-sensitive adhesive film, etc. comprising the acrylic pressure-sensitive adhesive composition according to the present invention as a masking tape for painting a car or a film for bonding electronic products, excellent initial adhesive force, adhesive holding power and re-adhesive power and also used If it needs to be discarded or separated afterwards, it can be easily detached and has the advantage that no adhesive residue remains on the product surface even after detachment.

Hereinafter, the present invention will be described in detail.

First, the acrylic pressure-sensitive adhesive composition according to the present invention will be described as follows.

The acrylic pressure-sensitive adhesive composition according to the present invention is based on acrylic pressure-sensitive adhesive resin. In the present invention, the acrylic pressure-sensitive adhesive resin is preferably an aqueous acrylic pressure-sensitive adhesive resin prepared by emulsion polymerization from an acrylic monomer or an oil-based acrylic pressure-sensitive adhesive resin prepared by solution polymerization or bulk polymerization from an acrylic monomer. Hereinafter, the manufacturing method of the said aqueous acrylic adhesive resin and oily acrylic adhesive resin is divided and demonstrated.

Water-based acrylic pressure-sensitive adhesive resin

In the present invention, the aqueous acrylic pressure-sensitive adhesive resin is 0.01 to 5 parts by weight of surfactant, 0.01 to 5 parts by weight of crosslinking agent, 100 to 100 parts by weight of the monomer mixture consisting of 80 to 99% by weight of the soft acrylic monomer and 1 to 20% by weight of the hard acrylic monomer. It can be prepared by emulsion polymerization by mixing 0.01 to 5 parts by weight of the initiator and 70 to 100 parts by weight of water.

The soft acrylic monomer serves to increase the initial adhesive strength and the adhesive holding force of the acrylic pressure-sensitive adhesive, the hard acrylic monomer serves to increase the cohesive force of the acrylic pressure-sensitive adhesive to play a role of leaving no residue after use.

In the present invention, the soft acryl-based monomer is butyl (meth) acrylate, hexyl (meth) acrylate, n-octyl (meth) acrylate, the glass transition temperature (Tg) of the homopolymer prepared therefrom is -20 ℃ or less, It may be selected from the group consisting of isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and isononyl (meth) acrylate, but is not limited thereto. In the present invention, the soft acrylic monomer is preferably 80 to 99% by weight based on the total monomer mixture. When the content of the soft acrylic monomer is less than 80% by weight, there is a problem in that the initial adhesive strength of the pressure-sensitive adhesive is weakened, and when the content of the soft acrylic monomer exceeds 99% by weight, there is a problem of weakening weather resistance and high temperature cohesion.

In the present invention, the hard acrylic monomer may be a (meth) acrylic acid, maleic acid, fumaric acid, acrylamide, N-vinyl pyrrolidone and N-vinyl caprolactam having a glass transition temperature (Tg) of at least 90 ° C of the homopolymer prepared therefrom. It may be selected from the group consisting of, but is not limited thereto. In the present invention, the hard acrylic monomer is preferably 1 to 20% by weight based on the total monomer mixture. If the content of the hard acrylic monomer is less than 1% by weight, there is a problem of weakening cohesion, weather resistance, weakening of adhesion, and the like, and if it exceeds 20% by weight, there is a problem of weakening the initial adhesive strength of the pressure-sensitive adhesive.

In the present invention, the surfactant used in the emulsion polymerization serves to facilitate the emulsion polymerization by activating the interface between the acrylic monomer and water, the surfactant in the present invention is known in the art Any surfactant can be used. Examples of the surfactant include, but are not limited to, anionic surfactants such as sulfone-based and amine-based, nonionic surfactants such as hydroxyl-based, or combinations thereof. In the present invention, the surfactant is preferably used in 0.01 to 5 parts by weight based on 100 parts by weight of the monomer mixture. If the surfactant is used less than 0.01 parts by weight of monomer micelles (micelle) is broken and there is a problem that is difficult to emulsify, when used in excess of 5 parts by weight there are a lot of residual surfactants have a problem in weather resistance, the problem that the molecular weight can be reduced It is not desirable to have.

In the present invention, in the emulsion polymerization of the acrylic monomer, a crosslinking agent is used. Crosslinking agent in the present invention serves to strengthen the adhesive strength through the cross-linking between the acrylic polymer in the polymerization process of the acrylic monomers and the adhesiveness of the adhesive. In the present invention, the crosslinking agent may be a thermal crosslinking agent or a photocrosslinking agent conventionally used in the art. For example, diacrylate crosslinking agent containing hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, and triethylene glycol diacrylate, triacrylate crosslinking agent, aziridine crosslinking agent, epoxy crosslinking agent Etc. may be used, but the present invention is not limited thereto. In the present invention, the crosslinking agent is preferably used in an amount of 0.01 to 5 parts by weight, more preferably 0.1 to 0.5 parts by weight, based on 100 parts by weight of the monomer mixture. If the amount of the crosslinking agent is less than 0.01 parts by weight, it may adversely affect cohesion or weather resistance. If the amount of the crosslinking agent is more than 2 parts by weight, the initial adhesive strength and overall adhesive properties may be deteriorated, which is not preferable.

In the present invention, in the emulsion polymerization of the acrylic monomer, a radical initiator is used. Radical initiators that can be used in the present invention may be used azo or peroxide initiators commonly used in the art. For example, benzoyl peroxide, tertiary butyl peroxide, dietary butyl peroxide, azobisisobutyronitrile and the like can be used, but are not limited thereto. In the present invention, the initiator is preferably used in 0.01 to 5 parts by weight, more preferably 0.1 to 1 parts by weight based on 100 parts by weight of the monomer mixture. If the amount of the initiator is less than 0.01 parts by weight, the polymerization does not proceed sufficiently to obtain the desired viscosity, and if it exceeds 5 parts by weight, the resulting polymer is too low in molecular weight, which is not preferable because the adhesive strength may drop.

In the present invention, in the emulsion polymerization of the acrylic monomer, water is used as a medium, and the amount of water used in the present invention is preferably 40 to 100 parts by weight based on 100 parts by weight of the monomer mixture. If the water is less than 40 parts by weight or more than 100 parts by weight, it is not preferable because it is difficult to produce a polymer having a desired viscosity and molecular weight.

In the present invention, the polymerization method of the acrylic monomer by the emulsion polymerization may be polymerized using a polymerization method commonly used in the art to which the present invention belongs, and the polymerization method does not limit the present invention, but for the efficiency of the initiator It is preferable to carry out at the temperature conditions of 40-80 degreeC. In addition, the weight average molecular weight of the polymer produced by the emulsion polymerization in the present invention is preferably 200,000 to 1,000,000, more preferably 400,000 to 600,000. If the weight average molecular weight is less than 200,000, the viscosity may be too low, the adhesive force may be lowered and the weather resistance may be lowered. If the weight average molecular weight is more than 1,000,000, the adhesive force is too high and the high temperature peelability required by the invention is weakened, which is not preferable. In the present invention, the viscosity of the polymer produced by the emulsion polymerization is preferably 2,000 to 100,000 cps, more preferably 4,000 to 8,000. If the viscosity is less than 2,000 cps, there is a problem that is difficult to apply to the pressure-sensitive adhesive tape and if it exceeds 100,000 cps there is a problem of poor workability is not preferable.

Oily Acrylic Adhesive Resin

In the present invention, the oil-based acrylic pressure-sensitive adhesive resin is prepared by a method that does not contain water, and may be prepared by using a method of solution polymerization or bulk polymerization according to the following method.

The method for producing the oil-based acrylic pressure-sensitive adhesive resin by the solution polymerization is 0.01 to 5 parts by weight of a crosslinking agent, 100 to 0.01 parts by weight of a monomer mixture consisting of 80 to 99% by weight of a soft acrylic monomer and 1 to 20% by weight of a hard acrylic monomer, and 0.01 to radical initiator. It can be carried out by mixing 5 parts by weight and 30 to 70 parts by weight of the reaction solvent. The soft acrylic monomer, the hard acrylic monomer, the crosslinking agent, and the radical initiator may be used in the same amount as the materials described in the method for preparing the aqueous acrylic pressure-sensitive adhesive resin. In addition, the reaction solvent may be used a reaction solvent commonly used in the art. For example, benzene, toluene, xylene, ethyl acetate and the like can be used, and the amount thereof is preferably 30 to 70 parts by weight based on 100 parts by weight of the monomer mixture. If the reaction solvent is less than 30 parts by weight or more than 70 parts by weight, it is not preferable because it is difficult to produce a polymer having a desired viscosity and molecular weight. The solution polymerization method may be carried out using the polymerization conditions commonly known in the art to which the reaction mixture belongs, the polymerization conditions do not limit the present invention, but the temperature of 40 to 80 ℃ for the efficiency of the initiator It is preferable to carry out in the range. In the present invention, the acrylic polymer prepared by the solution polymerization method has a weight average molecular weight of 200,000 to 1,000,000, and a viscosity of 2,000 to 100,000 cps, as described in the method of preparing the aqueous acrylic pressure-sensitive adhesive resin.

In addition, the method for producing the oil-based pressure-sensitive adhesive resin by the bulk polymerization is 0.01 to 5 parts by weight of the crosslinking agent and 0.01 to 5 parts by weight of the monomer mixture consisting of 80 to 99% by weight of the soft acrylic monomer and 1 to 99% by weight of the hard acrylic monomer. 5 parts by weight can be mixed. The soft acrylic monomer, the hard acrylic monomer, and the crosslinking agent may be used in the same amount as the materials described in the method for preparing the aqueous acrylic pressure-sensitive adhesive resin. In addition, the bulk polymerization method according to the present invention does not use a reaction solvent, and may be used by mixing a photoinitiator and a thermal initiator. Since polymerization by the photoinitiator may lower the polymerization efficiency, it is preferable to adjust the molecular weight and viscosity of the polymer to a desired range by using a thermal initiator mixed. As the photoinitiator that can be used in the present invention, benzoin methyl ether, benzoin isopropyl ether, anisoin methyl ether, benzoin, benzyl, benzyl ketal, etc. may be used, but is not limited thereto. In addition, the thermal initiator may be a peroxide-based or amine-based thermal initiator including benzoyl peroxide, but is not limited thereto. The polymerization method may be carried out using the polymerization conditions commonly known in the art to which the reaction mixture belongs, the polymerization conditions do not limit the present invention, but for the efficiency of the initiator 60 to 120 in the post-polymerization process It is preferable to carry out postpolymerization for 2 to 3 minutes in the temperature range of ° C. In addition, in the present invention, the acrylic polymer prepared by the bulk polymerization method may have a weight average molecular weight of 200,000 to 1,000,000 and a viscosity of 2,000 to 100,000 cps as described in the method of preparing the aqueous acrylic pressure-sensitive adhesive resin.

Next, the petroleum resin tackifier which is one component of the adhesive composition which concerns on this invention is demonstrated.

In general, acrylic pressure-sensitive adhesive resins are known to have a weaker adhesive force than rubber-based resins. Therefore, the pressure-sensitive adhesive composition according to the present invention includes a tackifier to increase the adhesive strength, in particular the initial adhesive strength of the acrylic pressure-sensitive adhesive resin.

The tackifier is a substance that is mixed with the adhesive resin to increase the initial adhesive strength and to increase the adhesive holding force. The conventional JP-A-1-98676, JP-A 64-60677, JP-A-63-256672, Republic of Korea Japanese Patent Application Laid-Open No. 2002-0056050 discloses a method of strengthening the adhesive force by using a rosin-based resin, a terpene-based resin, and a fiber-based resin as a tackifier. However, since the tackifiers are water-soluble, there is a problem that the resistance to water is weak when used in the pressure-sensitive adhesive. The present inventors have found that resistance to water is increased when petroleum resin-based tackifiers are used without using the water-soluble tackifiers. In particular, when the petroleum resin-based tackifier is mixed with the aqueous acrylic pressure-sensitive adhesive resin, it has been found that the problem of poor water resistance, which is a problem of the aqueous acrylic pressure-sensitive adhesive resin, can be remarkably improved.

In the present invention, the petroleum resin tackifier is preferably a polymer polymerized from a vinyl monomer containing acryloyl group or methacryloyl group in order to ensure compatibility with the acrylic pressure-sensitive adhesive resin. In addition, the vinyl monomer containing the acryloyl group or the methacryloyl group is preferably a vinyl monomer having 3 to 12 carbon atoms, more preferably a vinyl monomer having 5 to 9 carbon atoms. When the carbon number is less than 3, compatibility with the acrylic pressure-sensitive adhesive resin may be lowered. When the carbon number exceeds 12, viscosity control is not easy, so it is not preferable.

The polymer used as the tackifier in the present invention has a viscosity of 2,000 to 18,000 cps, preferably a weight average molecular weight of 500 to 50,000. If the viscosity is less than 2,000, there is a problem in that the adhesiveness is weakened, and if the viscosity exceeds 100,000, there is a problem in that workability is poor, which is not preferable. In addition, if the weight average molecular weight is less than 500, the adhesive strength is weakened, and if the weight average molecular weight exceeds 50,000, the tackifying function is weakened, which is not preferable.

The content of the tackifier in the present invention is preferably 5 to 30 parts by weight, more preferably 5 to 17 parts by weight based on 100 parts by weight of the acrylic pressure-sensitive adhesive resin according to the present invention. When the content of the tackifier is less than 5 parts by weight, the effect of initial adhesion and adhesion retention may be reduced. If the content of the tackifier is greater than 30 parts by weight, the relative content of the pressure-sensitive adhesive resin is reduced, and thus the adhesive strength is not preferable.

Next, the thermally expansible filler which is one component of the adhesive composition which concerns on this invention is demonstrated.

The acrylic pressure-sensitive adhesive composition according to the present invention includes a heat-expandable filler in order to facilitate the desorption from the product after use of the pressure-sensitive adhesive. The thermally expandable filler serves to facilitate desorption by reducing the contact area of the pressure-sensitive adhesive article, such as pressure-sensitive adhesive tape containing the product, such that the volume is expanded in a certain temperature range. In the present invention, the thermally expandable filler is preferably a material capable of expanding in a volume in a temperature range of 80 to 200 ℃, more preferably 100 to 200 ℃ more than the operating temperature of the acrylic pressure-sensitive adhesive article. Examples of thermally expandable fillers that may be used in the present invention include thermosetting or thermoplastic plastics, and more specifically, polymeric sphere expancel 551 DU sold by Akzo Nobel. Can be mentioned. In addition, the size of the thermally expandable filler in the present invention is preferably an average particle diameter of 6 to 32 ㎛. If the average particle diameter of the thermally expandable filler is less than 6 μm, the desorption efficiency may be poor and desorption may not proceed smoothly, and residues may remain even after desorption. If the average particle diameter of the thermally expandable filler exceeds 32 μm, the adhesive force may be reduced. Therefore, it is not preferable.

In the present invention, the thermally expandable filler may be added during the polymerization of the acrylic pressure-sensitive adhesive resin according to the present invention, may be mixed after the polymerization of the acrylic pressure-sensitive adhesive resin, this is not limiting the present invention.

The content of the thermally expandable filler in the present invention is preferably 1 to 40 parts by weight, more preferably 10 to 20 parts by weight based on 100 parts by weight of the acrylic adhesive resin according to the present invention. If the content is less than 1 part by weight, the desorption effect may be insufficient after use, leaving an adhesive residue. If the content is more than 40 parts by weight, the amount of the filler may be excessively large, which may reduce the adhesive force.

A process in which the pressure-sensitive adhesive article prepared from the pressure-sensitive adhesive composition including the thermally expandable filler is detached from the product used is well illustrated in FIG. 1. 1 is a schematic diagram showing a process of detaching the pressure-sensitive adhesive tape according to an embodiment of the present invention. Referring to FIG. 1, the pressure-sensitive adhesive tape including the pressure-sensitive adhesive resin and the tackifier 11 and the thermally expandable filler 12 is dried when the pressure-sensitive adhesive tape and the tackifier 11 are dried after the pressure-sensitive adhesive tape is applied. Adhesion to the used product occurs, and when heated thereafter, the thermally expandable filler 13 included in the pressure-sensitive adhesive composition expands, and the contact area between the pressure-sensitive adhesive tape and the used product decreases, so that desorption occurs.

Since the acrylic pressure-sensitive adhesive resin and the tackifier of the present invention is excellent in cohesion, there is an advantage in that the adhesive composition is desorbed without leaving the adhesive composition on the surface of the product used.

The present invention provides a pressure-sensitive adhesive article comprising the acrylic pressure-sensitive adhesive composition. In the present invention, the adhesive article may be a transfer tape, an adhesive tape including a double-sided tape, an adhesive film, or a hot melt, but is not limited thereto.

The process of manufacturing the pressure-sensitive adhesive tape according to an embodiment of the present invention is well shown in FIG. Figure 2 is a schematic diagram showing a manufacturing process of the pressure-sensitive adhesive tape according to an embodiment of the present invention. Referring to FIG. 2, the backing film 22 supplied through the backing film supply roll 24 passes through the coating machine 21 containing the pressure sensitive adhesive composition, and the pressure sensitive adhesive composition is coated on the upper surface thereof. After drying and post-polymerization takes place in the temperature range of 60 to 80 ℃ passing through the oven (23). The pressure-sensitive adhesive tape passing through the oven 23 is wound on a winding roll 25.

In the above, the acrylic adhesive composition which concerns on this invention, and the adhesive article manufactured from it were demonstrated.

Acrylic pressure-sensitive adhesive composition according to the present invention, including petroleum resin-based tackifiers excellent in initial adhesive strength and pressure-resistance, excellent water resistance, and includes a heat-expandable filler can be easily removable by heating during desorption after use.

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

Example

Preparation of Acrylic Pressure-sensitive Adhesive Resin

Production Example  One

100 parts by weight of a monomer mixture consisting of 25% by weight of butyl acrylate, 60% by weight of 2-ethylhexyl acrylate, 10% by weight of acrylic acid and 5% by weight of methyl methacrylate, 2.5 parts by weight of benzoyl peroxide as initiator, hexane as a crosslinking agent. 0.5 parts by weight of diol diacrylate, 5 parts by weight of sodium dodecyl sufate, an anionic surfactant as a surfactant, and 40 parts by weight of water were mixed, followed by 8 hours at a temperature of 60 ° C. in a reactor including a stirrer. Polymerization to give a polymer. The weight average molecular weight of the polymer was 400,000, and the viscosity was 5,000 cps.

Production Example  2

4 parts by weight of benzoyl peroxide as an initiator and hexanediol as a crosslinking agent in 100 parts by weight of a monomer mixture consisting of 25% by weight of butyl acrylate, 60% by weight of 2-ethylhexyl acrylate, 10% by weight of acrylic acid and 5% by weight of methyl methacrylate. 0.2 parts by weight of diacrylate and 50 parts by weight of toluene were mixed, and then polymerized in a reactor including a stirrer for 8 hours at a temperature of 70 ° C. to obtain a polymer. The weight average molecular weight of the polymer was 1,000,000 and the viscosity was 17,000 cps.

Production Example  3

Igacure 651 (Irgacure 651, Ciba) 1 as a photoinitiator in 100 parts by weight of a monomer mixture consisting of 25% by weight butyl acrylate, 60% by weight 2-ethylhexyl acrylate, 10% by weight acrylic acid and 5% by weight methyl methacrylate. After mixing parts by weight, 5 parts by weight of benzoyl peroxide as a thermal initiator and 1 part by weight of hexanediol diacrylate as a crosslinking agent, photopolymerization was carried out while irradiating UV with a UV lamp (Sankyo, 40W) in a reactor with a stirrer. Heat of 70 ° C conduction was added for 2 to 3 minutes to postpolymerize to obtain a polymer.

Petroleum Resin System  Tackifier

Hydrocarbon-based resin having 5 carbon atoms (LA-1100SE manufactured by Kolon Chemical) and hydrocarbon-based resin having 9 carbon atoms (LP-90E manufactured by Kolon Chemical) were used as it is.

Thermal expansion Filler

Polymer Sphere Expancel 551 DU sold by Akzo Nobel was used as it is.

Example  One

The pressure-sensitive adhesive composition uniformly mixed with 100 parts by weight of the petroleum resin-based tackifier and 30 parts by weight of the heat-expandable filler in 100 parts by weight of the aqueous acrylic pressure-sensitive adhesive resin prepared in Preparation Example 1 was evenly applied to a backing film with a thickness of 120 μm. After drying in an oven and then wound to prepare an adhesive tape.

Example  2

It carried out in the same manner as in Example 1 using the oil-based acrylic pressure-sensitive adhesive resin prepared in Preparation Example 2.

Example  3

It was carried out in the same manner as in Example 1 using the oil-based acrylic pressure-sensitive adhesive resin prepared in Preparation Example 3.

Comparative example  One

Using the aqueous acrylic pressure-sensitive adhesive resin prepared in Preparation Example 1 was carried out in the same manner as in Example 1, but without using a tackifier.

Comparative example  2

Using the aqueous acrylic pressure-sensitive adhesive resin prepared in Preparation Example 1 was carried out in the same manner as in Example 1, but used as a tackifier by mixing Aquatac 6080A of Arizona Chemical Co., Ltd., a rosin-based tackifier.

Examples 1 to 3 and Comparative Examples 1 to 2 are summarized in Table 1.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Acrylic adhesive resin (Production Example 1) 100 - - 100 100 Acrylic adhesive resin (Production Example 2) - 100 - - - Acrylic adhesive resin (Production Example 3) - - 100 - - Petroleum resin tackifier 20 20 20 - - Rosin Type Tackifier - - - - 20 Thermally expandable fillers 30 30 30 30 30

(Performance test)

The performance of the pressure-sensitive adhesive tapes prepared according to the methods of Examples 1 to 3 and Comparative Examples 1 to 2 was tested using the following method.

Adhesion

Based on the methods of ASTMD3121-94, D3654, D3330, etc., the adhesive force was evaluated as the load which loads in the 180 degree direction at 300 mm / min speed | rate by 1 inch width. The unit of adhesion is kgf / in.

Water resistance

According to ASTM D3564, the water resistance was evaluated as the time (h) that the adhesion was maintained in a constant temperature and humidity chamber (40 ° C. temperature / 80% humidity) after maintaining at room temperature for 24 hours after adhesion.

cohesion

Cohesion was evaluated as time (h) the adhesion at 60 ° C. was maintained according to ASTM D3654.

Desorption

After the adhesive tape was adhered to the coating plate, water was sprayed to qualitatively evaluate the detachment as follows.

 No residue on desorption: ◎, Some residue on desorption: ○, Many residues on desorption:

The performance test evaluation result of the said Examples 1-3 and Comparative Examples 1-2 was put together in Table 2.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Adhesive force (kgf / in) 3.5 4.2 4 2.5 3.6 Water resistance (h) 48 80 100     10 10 Cohesion (h) 120 180 1000 140 120 Desorption ◎ ◎ ◎ ◎ ◎

As can be seen from the results of Table 2, the pressure-sensitive adhesive composition of Examples 1 to 3 consisting of an aqueous acrylic pressure-sensitive adhesive resin or an oily acrylic pressure-sensitive adhesive resin, a petroleum resin-based tackifier and a heat-expandable filler, used a tackifier in terms of adhesive strength. It is much better than the case of Comparative Example 1 that is not, and compared with the case of Comparative Example 2 using a conventional rosin-based tackifier can be confirmed that the equivalent level or more. In addition, in terms of cohesion and desorption, the results were equivalent to those of Comparative Examples 1 and 2, and in particular, in terms of water resistance, the results of comparing Example 1 and Comparative Examples 1 to 2 were as follows. In addition, it can be seen that the conventional rosin-based tackifiers have been significantly improved.

The acrylic pressure-sensitive adhesive composition according to the present invention uses a petroleum resin-based tackifier to strengthen the initial adhesive strength in order to compensate for the fact that the initial adhesive strength in the conventional acrylic pressure-sensitive adhesive somewhat lower. In the case of the aqueous acrylic pressure-sensitive adhesive may also be improved in water resistance. In addition, since the acrylic pressure-sensitive adhesive composition according to the present invention includes a thermally expandable filler therein, it may be easily removed by expanding the filler by heating when necessary to remove it after use.

Although the present invention has been described above through specific embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the technical idea of the present invention, and such modifications and modifications belong to the appended claims.

Claims (17)

Acrylic adhesive resins; Petroleum resin tackifiers; And thermally expandable fillers, An acrylic pressure sensitive adhesive composition wherein the petroleum resin tackifier is a polymer polymerized from a (meth) acryloyl group-containing vinyl monomer having 3 to 12 carbon atoms. The method of claim 1, Acrylic adhesive composition, characterized in that the acrylic adhesive resin is an aqueous acrylic adhesive resin or an oil-based acrylic adhesive resin. The method of claim 2, The aqueous acrylic adhesive resin is 80 to 99% by weight of a flexible acrylic monomer; 100 parts by weight of the monomer mixture composed of 1 to 20% by weight of the hard acrylic monomer, 0.01 to 5 parts by weight of the surfactant, 0.01 to 5 parts by weight of the crosslinking agent, 0.01 to 5 parts by weight of the radical initiator, and 70 to 100 parts by weight of the emulsion to mix Acrylic pressure-sensitive adhesive composition, characterized in that prepared. The method of claim 2, The oil-based acrylic adhesive resin is 80 to 99% by weight of a flexible acrylic monomer; It is prepared by solution polymerization by mixing 0.01 to 5 parts by weight of a crosslinking agent, 0.01 to 5 parts by weight of a radical initiator, and 30 to 70 parts by weight of a reaction solvent to 100 parts by weight of a monomer mixture composed of 1 to 20% by weight of a hard acrylic monomer Acrylic pressure-sensitive adhesive composition. The method of claim 2, 80 to 99% by weight of the acrylic adhesive resin is a flexible acrylic monomer; An acrylic pressure-sensitive adhesive composition prepared by mass polymerization by mixing 0.01-5 parts by weight of a crosslinking agent and 0.01-5 parts by weight of a mixed initiator of a photoinitiator and a thermal initiator with 100 parts by weight of a monomer mixture composed of 1 to 20% by weight of a hard acrylic monomer. The method according to any one of claims 3 to 5, The soft acrylic monomers are butyl (meth) acrylate, hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and isononyl (meth) The acrylic pressure-sensitive adhesive composition, characterized in that selected from the group consisting of. The method according to any one of claims 3 to 5, The acrylic adhesive composition, wherein the hard acrylic monomer is selected from the group consisting of (meth) acrylic acid, maleic acid, fumaric acid, acrylamide, N-vinyl pyrrolidone and N-vinyl caprolactam. The method according to any one of claims 3 to 5, Acrylic cross-linking agent is selected from the group consisting of hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate and triethylene glycol diacrylate. The method of claim 2, The acrylic pressure-sensitive adhesive composition, characterized in that the weight average molecular weight of the aqueous acrylic pressure-sensitive adhesive resin or oily acrylic pressure-sensitive adhesive resin is 200,000 to 1,000,000, the viscosity is 2,000 to 100,000 cps. delete The method of claim 1, Acrylic polymer composition, characterized in that the viscosity of the polymer is 1,000 to 80,000cps, the weight average molecular weight is 500 to 50,000. The method of claim 1, The acrylic pressure-sensitive adhesive composition, characterized in that the content of the petroleum resin tackifier is 5 to 30 parts by weight based on 100 parts by weight of the acrylic adhesive resin. The method of claim 1, The thermally expandable filler is an acrylic pressure-sensitive adhesive composition, characterized in that the thermosetting or thermoplastic plastics thermal expansion at 80 to 200 ℃. The method of claim 1, Acrylic adhesive composition, characterized in that the size of the thermally expandable filler has an average particle diameter of 6 to 32 ㎛. The method of claim 1, Acrylic adhesive composition, characterized in that the content of the thermally expandable filler is 15 to 40 parts by weight based on 100 parts by weight of the acrylic adhesive resin. An adhesive article comprising the pressure sensitive adhesive composition of claim 1. The method of claim 16, The pressure-sensitive adhesive article, characterized in that the pressure-sensitive adhesive article is a pressure-sensitive adhesive tape, pressure-sensitive adhesive film or hot melt.

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