JP2002129134A - Recyclable water-based adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based adhesive which can give a bonded panel composed of a porous board and a decorative metallic sheet bonded thereto and from which the constituents can be recycled by re-releasing them without breaking them. SOLUTION: An adhesive panel prepared by bonding a decorative metallic sheet to a porous board with an adhesive comprising (A) an aqueous polymer dispersion capable of forming a film having a tensile strength of 1-28 MPa and an elongation of 100-2,000% when dried and (B) thermally expandable particulate hollow body is exposed to a hot atmosphere, whereupon the adhesive panel can be separated into the porous board and the decorative metallic sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in an adhesive panel formed by bonding a porous metal board to a decorative metal sheet having an adhesive surface such as a color-painted metal sheet or a metal sheet subjected to phosphate treatment or anodization. The present invention relates to a water-based adhesive composition having improved adhesiveness, water resistance, and heat resistance and excellent in re-peeling work due to poor adhesion and re-peeling work for future recycling.

[0002]

2. Description of the Related Art Conventionally, adhesive panels have been widely used in the fields of building materials such as offices, condominiums and houses, housing equipment and vehicles. These include steel plates or other metal plates with a color-coated adhesive surface, or phosphate-treated steel plates, anodized aluminum plates, or other surface-treated metal plates. A composite material obtained by attaching a porous board such as a gypsum board to a difficult-to-adhere material (referred to as a “glue panel”).

[0003] By the way, when renovating or dismantling work such as office materials, condominiums, houses, and other building materials, housing equipment, and vehicles, they are released into the environment as a great deal of industrial waste, which has been a serious social problem. Is one of the causes. In particular, in the case where the decorative metal plate is collectively processed without re-peeling from the adhesive panel, it is not suitable for recycling, and there is a possibility that the environment is further destructed.

In order to facilitate re-peeling in consideration of recycling in advance, it is used for bonding between woods.
In a decorative plate in which a decorative metal plate is bonded with a weak adhesive material, such as an acrylic adhesive, which is an adhesive disclosed in Japanese Patent No. 61468, peeling or floating easily occurs during daily use as a building material or a home appliance. The use of such materials for homes, vehicles, and the like, which require durability, has been a fundamental problem. That is, the adhesive panel, which is an adhesive product, must have basic performance that can be used with peace of mind when in use, and must be removable as easily as possible without destruction of the material when unnecessary. If the material can be easily peeled off without destruction of the material, there is an advantage that the material can be recycled and reused.

[0005] Unfortunately, however, there has not yet been found any convenient adhesive which gives the required quality and performance when needed and can be easily peeled off when unnecessary.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a decorative metal plate, which is a hard-to-bond material, with excellent adhesion, to provide a basic performance that can be used safely at the time of use, and to recycle such as re-peeling in the future. It is to develop an adhesive that takes into consideration the technology.

[0007] The reason why the decorative metal plate is difficult to bond is that a color-coated steel plate whose other surface (bonding surface) is coated with a polymer paint such as an epoxy coat or a PVC coat, another metal plate, or phosphorus This is because it is a steel plate subjected to a salt treatment or an aluminum plate subjected to anodization.
Therefore, the adhesive must basically adhere well to these materials.

[0008] Since these adhesive panels are used for building materials, housing equipment, and the like, they must be adhesives that exhibit performance levels such as water resistance and heat resistance that pass quality requirements tests in the industry.

Further, the adhesive panel needs to maintain a sufficient adhesive state and adhesive performance when it is used as an adhesive product, and the decorative metal plate and the porous board are in a state of spontaneous peeling when recycled. Alternatively, it must be an adhesive having a peeling easiness such that only the decorative metal plate can be easily peeled off by hand.

[0010]

Means for Solving the Problems The present inventors have started research on blending a heat-expandable fine hollow particle, that is, a heat-expandable microcapsule, with an emulsion adhesive. These heat-expandable fine hollow particles are widely used in industrial materials utilizing heat expandability.

In the case of an adhesive panel, if only the adhesiveness to difficult adhesion is considered, the problem can be solved by blending a heat-expandable fine-grained hollow body with a pressure-sensitive adhesive such as an acrylic adhesive. It is not at all suitable for the industry's quality requirements test, such as performance.

When the heat-expandable fine hollow particles are blended with an aqueous adhesive, the adhesive and water resistance originally possessed by the adhesive tend to decrease, and therefore, these disadvantages must be covered. Therefore, we decided to develop an adhesive that incorporates a heat-expandable fine-grained hollow body, and that exhibits excellent adhesiveness to decorative boards, and a performance level that passes industry quality requirements such as water resistance and heat resistance. We continued our research.

Furthermore, under the premise that the decorative board has excellent adhesiveness, water resistance, heat resistance, and other performance levels, it is necessary to check whether the decorative metal sheet and the porous board are in a spontaneously peeled state when recycled. In order to make the adhesive having the ease of peeling such that only the metal plate can be easily peeled by hand,
Since it is necessary to find a property that can make maximum use of the expansion force of the heat-expandable fine-grained hollow body, further studies have been made.

Even when the thermally expandable fine hollow particles are blended, the decorative board is provided with excellent adhesiveness and performance levels such as water resistance and heat resistance, and the expansion power of the thermally expandable fine hollow particles is maximized. Finally, the present invention has been completed by finally finding the characteristics that can be used.

Hereinafter, means of the present invention for solving the above-mentioned problems will be described.

According to the first aspect of the present invention, A) the formed film after drying has a tensile strength of 1 to 28 MPa and an elongation of 100 to 20 MPa.
An aqueous adhesive composition for a removable adhesive panel, comprising an aqueous dispersion containing a polymer having a property of 00% and (B) a thermally expandable fine hollow particle.

In the present invention, when a polymer material having a tensile strength and an elongation rate of (A) a formed film after drying is in this region, the adhesiveness to a decorative metal plate is relatively excellent,
The adhesive performance is maintained during use, and the expansion power of the thermally expandable fine hollow particles can be used effectively.
It is possible to give a peeling easiness such that only the decorative metal plate can be easily peeled off by hand.

In the invention of claim 2, the aqueous dispersion containing the polymer of component A) is selected from polyvinyl acetate-based polymers, urethane-based polymers, acrylic polymers, silicone-based polymers, chloroprene elastomers, and styrene-butadiene elastomers. The aqueous adhesive composition for a removable adhesive panel according to claim 1, wherein the aqueous adhesive composition comprises one or more polymers.

According to a third aspect of the present invention, the aqueous dispersion containing the polymer of the component (A) comprises an ethylene-vinyl acetate copolymer emulsion. It is an aqueous adhesive composition for an adhesive panel.

According to a fourth aspect of the present invention, the aqueous dispersion containing the polymer of the component (A) comprises an ethylene-vinyl acetate copolymer emulsion and an anionic polyurethane emulsion. The water-based adhesive composition for a removable adhesive panel according to the above.

According to the third or fourth aspect of the present invention, the heat-expandable fine particles are excellent in suitability for a production line, give the most excellent adhesiveness to a decorative metal plate, exhibit quality properties such as water resistance and heat resistance. Because the hollow body has excellent followability of expansion, re-peeling performance during recycling is also excellent.

In particular, when an ethylene-vinyl acetate copolymer emulsion and an anionic polyurethane emulsion, particularly an anionic polyurethane emulsion modified with sulfonic acid, are blended, the adhesiveness and water resistance are reduced due to the blending of the heat-expandable fine hollow particles. Can be suppressed.

Further, when the ethylene-vinyl acetate copolymer emulsion has a property that the toluene-insoluble content is 70% by mass or more, the effect of suppressing the decrease in adhesiveness and water resistance due to the addition of the heat-expandable fine hollow particles. Is remarkable.

According to a fifth aspect of the present invention, the thermally expandable fine hollow particles of the component (B) have an expansion ratio of 20 to 100 times and an expansion start temperature of 90 to 150 ° C. 5. A removable adhesive water-based adhesive composition for an adhesive panel according to any one of the above-mentioned means.

When the thermally expandable fine hollow particles having the above properties are used, a sufficient bonding state and bonding performance can be maintained when used as an adhesive product, and the heating time for recycling is relatively short. It can be done in a short time.

In the invention of claim 6, the thermally expandable fine hollow particles of the component (B) are composed of the polymer solid content of the component (A) of 1%.
The adhesive composition for an adhesive panel according to any one of claims 1 to 5, wherein 2 to 100 parts by mass is blended with respect to 00 parts by mass.

If this blending region is selected, the adhesiveness and water resistance of the heat-expandable fine hollow particles are relatively low, and the expansion force of the heat-expandable fine hollow particles can be maximized. When 5 to 75 parts by mass is selected among these, the decrease in adhesion and water resistance is the least, and the expansion force of the thermally expandable fine hollow particles can be maximized.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, (A) the formed film after drying has a tensile strength of 1 to 28 MPa and an elongation of 100%.
It begins with a determination of whether the polymer has 特性 2000% properties. When measuring these, if the dry film of the aqueous dispersion containing the polymer is in this range,
It can be used as it is. If not in this range, a softener such as a plasticizer or a reinforcing agent such as an inorganic filler may be adjusted to have the physical properties in this region.

(A) When the formed film after drying has a tensile strength, that is, a strength of less than 1 MPa, the cohesive force is insufficient.
When the adhesive performance cannot be maintained when used as an adhesive panel and exceeds 28 MPa, the effect of the present invention cannot be obtained by suppressing the expansion of the thermally expandable fine hollow particles. If the elongation percentage of the formed film after drying is less than 100%, the effect of the present invention cannot be obtained by suppressing the expansion of the thermally expandable fine hollow particles, and if it exceeds 2000%, the cohesive force is insufficient. Adhesive performance cannot be maintained when used as an adhesive panel.

[0030] The most effective physical properties providing the effect of maintaining the adhesiveness, the adhesive performance during use, and maximizing the expansion of the heat-expandable fine hollow particles are 3 to 15 MPa, and the elongation rate is 200 to 200.
It is in the range of 1500%.

A method for obtaining this formed film can be obtained by uniformly applying an aqueous dispersion containing a polymer on release paper or the like, and then drying it naturally. Confirmation of the characteristics of the formed film can be determined by a method based on JIS K6251. Here, the film tensile strength is the maximum breaking strength at a normal temperature of 23 ° C., and the elongation is the maximum elongation at that time. In the case where (B) a thermally expandable fine hollow particle is blended,
Since the maximum strength and elongation are affected by the degree of homodispersion, the determination must be made without blending.

(A) The advantage of selecting an aqueous dispersion containing a polymer is (B) the ease of mixing of the thermally expandable fine hollow particles,
Adhesive panels are easy to produce, suitable for production lines, and consider safety, hygiene, and the environment. (A) Aqueous dispersion containing polymer (B) The method of blending the heat-expandable fine hollow particles is as follows. The aqueous dispersion containing (A) polymer is charged using an aqueous processing vessel, and (B) heat-expandable After compounding the fine hollow particles, they can be obtained by homogenous mixing. The aqueous dispersion containing the polymer (A) may be blended with the polymer solution obtained by emulsion polymerization and (B) the hollow particles having thermal expansion properties may be blended into a drum as in a production site using a simple stirring device. Good. (B) It is an advantageous method to blend the thermally expandable fine hollow body gradually to obtain a homogeneous mixture.

(A) The aqueous dispersion (ie, polymer emulsion) containing the polymer is at least one selected from the group consisting of a polyvinyl acetate polymer, a urethane polymer, an acrylic polymer, a silicone polymer, a chloroprene elastomer and a styrene butadiene elastomer. May be selected. The polyvinyl acetate-based polymer is a polyvinyl acetate homopolymer, an ethylene-vinyl acetate-based copolymer, an ethylene-vinyl acetate-acrylate-based copolymer, or a vinyl acetate-acrylate-based copolymer. The acrylic polymer is a (meth) acrylate-based copolymer or a (meth) acrylate-styrene copolymer. An anionic polyurethane emulsion is a polyurethane emulsion having anion electrification in the molecule. Among them, the sulfonic acid-modified anionic polyurethane polymer is a urethane polymer having a sulfonate group in the urethane polymer molecule and usually being a sulfonate salt and being emulsion-stable. The water-dispersible silicone polymer is a silicone polymer having a skeleton having an organosilane structure, and a modified silicone polymer having a main chain structure of polyoxypropylene.

In the present invention, as the component (A), an adhesive comprising an ethylene-vinyl acetate copolymer emulsion or an ethylene-vinyl acetate copolymer emulsion and an anionic polyurethane emulsion, particularly an anionic polyurethane emulsion modified with sulfonic acid. By selecting the agent, it is suitable for production lines in panel factories, etc., gives the best adhesion to decorative metal sheets, expresses quality performance such as water resistance and heat resistance, and expands the thermally expandable fine hollow particles Because of the excellent followability, the re-peeling performance during recycling is also excellent. Further, when the ethylene-vinyl acetate copolymer emulsion has a property that the toluene-insoluble content is 70% by mass or more, the effect of suppressing the decrease in adhesiveness and water resistance due to the blending of the thermally expandable fine hollow particles is remarkable. Become. When an ethylene-vinyl acetate copolymer emulsion having a toluene insoluble content of 70% by mass or more and a sulfonic acid-modified anionic urethane emulsion are particularly combined, the adhesiveness, which is an adverse effect of the blending of the thermally expandable fine hollow particles, In addition, a decrease in water resistance can be suppressed to the utmost.

This is a polyvinyl alcohol-containing ethylene-vinyl acetate-polyfunctional monomer copolymer emulsion having a toluene insoluble content of 70% by mass or more. They are,
It can be obtained by using the manufacturing method disclosed in Japanese Patent Application Laid-Open No. 9-194811. The urethane emulsion having the property of being sulfonate-modified is preferably an aromatic anionic urethane emulsion having a sulfonic acid group and a polyester skeleton.

Further, when a high degree of water resistance, heat resistance, boiling resistance, etc. is required for an exterior adhesive panel or the like, a crosslinking agent represented by a polyisocyanate compound or an epoxy compound may be added to the adhesive of the present invention. it can.

In the present invention, the thermally expandable fine hollow body is
A component that is blended to re-peel only the decorative metal plate by heating, and has a foaming ratio of 20 to 100 times and a foaming start temperature of 90 to 150 ° C. Such a heat-expandable fine hollow body is a fine hollow body made of a plastic sphere having an average particle diameter of 3 to 30 µ generated in a polymer shell containing a liquid gas, and when heated, the gas pressure inside the shell is reduced. The softening of the thermoplastic shell increases the volume dramatically and results in hollow spherical particles. In the thermally expandable fine hollow particles having an expansion ratio of less than 20 times, the re-peeling performance tends to decrease, and in the thermally expandable fine particles having an expansion ratio of more than 100 times, the foaming start temperature exceeds 150 ° C. Due to the tendency, it is necessary to set the heating temperature high and set the time long. The average particle size of the thermally expandable fine hollow particles is very important. If the average particle size is less than 3 μm, the removability and the dispersibility during mixing may be reduced. If it exceeds 30μ, the tendency to form coarse particles during mixing increases. In particular, the average particle size is 9 to
The present invention can be implemented most effectively by selecting a thermally expandable fine hollow body in the range of 17μ. A plastic sphere is preferable because an acrylic polymer containing no chlorine compound does not generate dioxin and can maximize compatibility with an ethylene-vinyl acetate copolymer emulsion and expandability. Commercially available products can be used for these thermally expandable fine hollow bodies,
Commercially available products include, for example, EXPANCEL053
DU (Expancel, expansion ratio 35 times, expansion start temperature 101 ° C).

The aqueous adhesive composition of the present invention can be obtained by mixing (A) an aqueous dispersion containing a polymer, that is, a polymer aqueous emulsion and (B) a heat-expandable fine hollow particle, or (A) ethylene-vinyl acetate. The preferred range of the mixing ratio of the system copolymer emulsion and (B) the heat-expandable fine hollow particles is 2 to 100 parts by weight, particularly 100 parts by weight (solid content) of component (A). 5-7
It is preferably 5 parts by mass. If the amount of the component (B) is too small, it is difficult to remove again.
Poor workability when using an adhesive and a tendency to increase costs arise.

In the adhesive of the present invention, a thickener, pH
Adjusters, fillers, organic solvents, plasticizers, defoamers, and fungicides can be added.

In describing the embodiments of the present invention,
An ethylene-vinyl acetate copolymer emulsion or an ethylene-vinyl acetate copolymer emulsion and a sulfonic acid-modified anionic polyurethane emulsion will be described in detail as a polymer aqueous emulsion. The decorative metal plate will be described using a color steel plate.

The adhesive for an adhesive panel of the present invention can be produced on a production line commonly used in the industry.
That is, usually, an adhesive is applied to the surface of a porous board such as a gypsum board using a spreader, a nozzle applicator, or the like, and a decorative metal plate is placed on the porous board. It can be manufactured by crimping with a press.
At this stage, if a flaw or a coating defect is found on the surface of the decorative panel, re-peeling by the following method is also an advantage of the present invention in that bonding can be performed again.

The adhesive panel thus obtained is widely used in the fields of building materials such as offices, condominiums and houses, housing equipment and vehicles.

Conventionally, these adhesive panels have been disposed of as troublesome industrial wastes after being dismantled.
When the adhesive of the present invention is used, it can be recycled by re-peeling. At the time of re-peeling, the adhesive panel
By leaving it for 20 minutes or more in the above atmosphere and immediately forcibly peeling it off by hand or the like, a decorative metal plate and a porous board such as a gypsum board can be separated and peeled again. In addition,
When left at 120 ° C. for a long time (about 1 hour), the same effect is observed. When increasing the efficiency of these re-peeling,
At the time of heating, ultraviolet irradiation, infrared radiation, or far infrared radiation can be used in combination. The decorative metal plate thus separated by re-peeling can be reused by polishing and repainting. If the porous board has little damage, it can be reused as it is. If both are badly scratched or stained, the metal decorative board can be reused by re-melting and the porous board can be reused by re-crushing. In the unlikely event that it has to be discarded, it is separated so that the burden on the environment can be significantly reduced compared to the past.

[0044]

EXAMPLES The present invention will be described in detail with reference to Examples below, but the present invention is not limited to these Examples.

Production of EVA (1) A polyvinyl alcohol-containing ethylene-vinyl acetate-polyfunctional monomer copolymer emulsion having a toluene insoluble content of 70% by mass or more has a mass ratio of ethylene / vinyl acetate of 17/83, It is a copolymer obtained by selecting triallyl isocyanurate as a functional monomer and copolymerizing the polyfunctional polymer / vinyl acetate so that the mass ratio thereof becomes 0.1 / 100. A polyvinyl alcohol aqueous solution was charged into a pressure polymerization apparatus so as to be 5% by mass of all the polymers, and ethylene gas corresponding to the design value was sealed. Then, a mixed solution of vinyl acetate and a polyfunctional monomer was added dropwise, At 50-70 ° C by emulsion polymerization. This polymer had a toluene-insoluble content of 92.5% by mass and had a viscosity of 2
000 mPa · s / 25 ° C., solid content 55.3% by mass, p
H4.6, film tensile strength 9.8MPa, elongation 700
%Met. This resin emulsion is referred to as EVA (1).

Example 1 (A) Sumikaflex 400 (manufactured by Sumitomo Chemical Co., Ltd.) as an ethylene-vinyl acetate-based copolymer emulsion
Manufactured, solid content concentration 55% by mass, pH 5, film tensile strength 7.4 MPa, elongation 520%, hereinafter, "SF400"
It is described. ), And 100 parts by mass (solid content) of the component (A), EXPANCEL053DU (manufactured by Expancel, Inc.)
30 parts by mass of a foaming magnification of 35 times and a foaming start temperature of 101 ° C.) were added and mixed to obtain an aqueous adhesive composition.

(Examples 2 to 6, Comparative Examples 1 and 2) Panflex OM-4000 (manufactured by Kuraray Co., Ltd.) having the compounding amount shown in Table 1, solid content concentration 56% by mass, pH 5, film tensile strength 4.0 MPa, Elongation rate 1000%, below, "OM400
0 ". ), EVA (1), Panflex O
M-3100 (manufactured by Kuraray Co., Ltd., solid content concentration: 47% by mass, pH: 5, film tensile strength: 0.6 MPa, elongation: 30)
00% or more, hereinafter referred to as “OM-3100”. ), Sumikaflex 480 (Sumitomo Chemical Industries, Ltd.)
Manufactured, solid content concentration 55 mass%, pH 5, film tensile strength 2
9.0 MPa, 0% elongation, hereinafter referred to as “SF480”. ) Aromatic anionic polyurethane emulsion modified with sulfonic acid, that is, having a polyester skeleton having a sulfonic acid group (solid content: 45% by mass, pH: 8,
Film tensile strength 30 MPa, elongation 665%, below
It is described as "S group-containing PU". A water-based adhesive composition was obtained in the same manner as in Example 1 except that [the above-mentioned component (A)] and the thermally expandable fine hollow particles [the above-mentioned component (B)] were used. In Table 1, the numerical values of the components A and B indicate parts by mass.

The aqueous adhesive compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were subjected to the following performance evaluations, and the results are shown in Table 1.

[0049]

[Table 1]

As described above, in Examples 1 to 4, the adhesive was not adhered to the decorative metal plate by leaving it in a hot air circulator of 150 ° C. or more for 20 minutes, having a practical adhesive strength. That is, re-peeling was confirmed in the state of interfacial peeling. In Examples 5 and 6, the addition of a sulfonic acid-modified anionic polyurethane emulsion improves the normal-state and wet heat-resistant adhesive strengths, and the ethylene-vinyl acetate copolymer emulsion having a toluene-insoluble content of 70% by mass or more. In particular, the effect is remarkably exhibited in the combination, and furthermore, in a hot air circulator of 150 ° C. or more,
It was confirmed that the film was peeled off again after being left for a minute. In addition, in the aqueous adhesive compositions of Examples 5 to 6, it was confirmed that a decorative metal sheet in which an adhesive surface was a steel sheet subjected to only an rust-proof treatment with an epoxy resin (polymer) coat and phosphoric acid was confirmed. The effect was recognized. In Comparative Examples 1 and 2, the tensile strength of the film of the component (A) was 1
~ 28MPa and elongation percentage of film is 100 ~ 200
It was confirmed that when the value deviated from the range of 0%, re-peeling was not possible.

(Preparation of Adhesive Panel Sample) The obtained aqueous adhesive composition was uniformly applied to a 12.0 mm-thick gypsum board using a rubber roll so as to have an application amount of 110 g / m ^2. 1.0 mm on the adhesive composition coated surface
After bonding a decorative metal plate with a thick adhesive surface coated with a PVC resin (polymer), 0.5M at 22 ° C atmosphere
It pressed at the pressure of Pa for 1 hour. After the pressure was released, it was left to cure at the same temperature for 5 days to prepare an adhesive panel sample.

(Normal Bonding Strength Test) The obtained adhesive panel sample was cut so as to leave a bonded portion of 25 mm square, and was subjected to Autograph AG-5 at 22 ° C. in an atmosphere.
000A (made by Shimadzu Corporation), 50 mm
The adhesive strength at the time of tensile shearing at a rate of / min was measured.

(Moisture and Heat Adhesion Strength Test) The obtained adhesive panel sample was cut so as to leave a bonded portion of 25 mm square, left at 40 ° C. in a 90% RH atmosphere for 48 hours, and then immediately Using the graph AG-5000A, the adhesive strength at the time of tensile shearing at a speed of 50 mm / min was measured.

(Repeeling test with hot air circulator) Adhesion The obtained decorative board sample was cut into a 150 mm square, and the hot air circulator HIS manufactured by Kusumoto Kasei Co., Ltd. was adjusted to each temperature shown in Table 1.
It was left in PEC HT210 for 20 minutes to evaluate the state of re-peeling.

The evaluation of the state of re-peeling is based on the following criteria. ○: Immediately after peeling by hand, if just peeled by hand, only the decorative metal plate peels off in an interface peeling state. X: Three-stage evaluation of immediately peeling by hand after standing and peeling in the state of paper breakage of the gypsum board. Of these criteria, the practical range of the present invention is ○.

(Examples 7 to 12 and Comparative Examples 4 to 6) The formulations of the adhesives of Examples 7 to 12 and Comparative Examples 4 to 6 shown in Table 2 were as follows.
It is the same as Examples 1 to 6 and Comparative Examples 1 to 3 shown in Table 1.
In the experiment of Table 2, in order to clearly evaluate the difference between the adhesiveness and the water resistance, an epoxy-coated 1.0 mm-thick decorative metal plate and a 10 mm-thick plywood for concrete panel (the plywood for a concrete panel with a poor adhesion surface) were used. Control panel plywood).

[0057]

[Table 2]

(Preparation of Adhesive Panel Sample) The obtained aqueous adhesive composition was uniformly applied on a control panel plywood having a thickness of 10 mm using a rubber roll so as to have an application amount of 150 g / m ^2. After a decorative metal plate (backside epoxy-coated steel plate) having a thickness of 1.0 mm was bonded to the surface on which the composition was applied, the plate was pressed at a pressure of 0.5 MPa in a 22 ° C. atmosphere for 3 hours. After the pressure was released, it was left to cure at the same temperature for 5 days to prepare an adhesive panel sample.

(Normal Adhesion Strength Test) The obtained adhesive panel sample was used as a test piece. This was subjected to an adhesion test using a plane tensile test described in JAS special plywood. 25
Cutting so that the bonded part of mm square remains, 22
Autograph AG-5000A
Using (manufactured by Shimadzu Corporation), the adhesive strength at the time of tensile shearing at a speed of 5 mm / min was measured.

(Water Resistant Bond Strength Test) A test piece was prepared from the obtained adhesive panel sample in the same manner as in the normal bond strength test, and immersed in 23 ° C. room temperature water for 3 hours.
Immediately, using Autograph AG-5000A, 5
The adhesive strength when subjected to tensile shear at a speed of mm / min was measured.

(Removal Test Using Hot Air Circulator) The obtained decorative board sample was cut into 150 mm squares, and
Hot air circulator HISPECH manufactured by Kusumoto Kasei Co., Ltd.
The temperature of T210 was adjusted to 150 ° C. and evaluated after standing for 20 minutes. Evaluation criteria are the same as in Examples 1 to 6.

[0062]

As described above, the present invention relates to (A)
An aqueous adhesive composition comprising a polymer having characteristics of a tensile strength of the formed film after drying of 1 to 28 MPa and an elongation of 100 to 2000% and (B) a heat-expandable fine hollow particle is defined as an adhesive. By doing this, it is possible to re-peel the adhesive panel with the decorative metal plate bonded to the porous board using this adhesive, without causing material breakage in a heated atmosphere. Since only the board can be peeled off in the interface peeling state, the equipment and equipment made of the adhesive panel consisting of the porous board and the decorative metal plate can be easily peeled off and recycled without harming the environment. It has excellent effects.

Claims (6)

[Claims] 1. An aqueous dispersion containing a polymer having characteristics of (A) a tensile strength of a formed film after drying of 1 to 28 MPa and an elongation of 100 to 2000%, and (B) a thermally expandable fine hollow particle body. A water-based adhesive composition for a removable adhesive panel, comprising: 2. The aqueous dispersion containing the polymer of the component (A) is at least one selected from the group consisting of polyvinyl acetate-based polymers, urethane-based polymers, acrylic polymers, silicone-based polymers, chloroprene elastomers, and styrene-butadiene elastomers. The water-based adhesive composition for a removable adhesive panel according to claim 1, further comprising a polymer. 3. The water-based adhesive for a removable adhesive panel according to claim 1, wherein the aqueous dispersion containing the polymer as the component (A) comprises an ethylene-vinyl acetate copolymer emulsion. Composition. 4. The removable peelable composition according to claim 1, wherein the aqueous dispersion containing the polymer of the component (A) comprises an ethylene-vinyl acetate copolymer emulsion and an anionic polyurethane emulsion. An aqueous adhesive composition for an adhesive panel. 5. The heat-expandable fine hollow particle of the component (B) has an expansion ratio of 20 to 100 times and an expansion start temperature of 90 to 100.
The aqueous adhesive composition for a removable adhesive panel according to any one of claims 1 to 4, wherein the aqueous adhesive composition is at 150C. 6. The thermally expandable fine hollow particles of the component (B) include:
The adhesive composition for an adhesive panel according to any one of claims 1 to 5, wherein 2 to 100 parts by mass is blended with respect to 100 parts by mass of the polymer solid content in the component (A). .