JP2002003800A - Recyclable adhesive tape repeelable by heat-foaming - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a repeelable adhesive tape that is readily and efficiently peelable by utilizing the foam formation by heat with no adverse effect to environment. SOLUTION: The objective recyclable adhesive tape repeelable by the heat foaming is prepared by formulating 10-30 mass parts of thermally expandable fine hollow particles into 100 mass parts of an active energy-curable adhesive, applying the formulated adhesive to the tape base material or mold release paper and curing the resultant tape or paper with active energy rays.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive tape from which an adherend bonded by an adhesive tape is easily or automatically peeled off by heat treatment.

[0002]

2. Description of the Related Art In recent years, various combinations of different materials have been used in automobiles, electric appliances, household goods, and the like in consideration of their structure, cost, and functionality. However, when recycling these commodities, it is necessary to disassemble and collect various materials. For this purpose, it is necessary to peel off the joining portion and further remove the adhesive or the adhesive tape used for the joining, which requires a great deal of labor and time for separation. There is a demand for an adhesive tape which is easily peeled off or peels off automatically due to some external factors.

Hitherto, as such a peeling adhesive tape, an adhesive tape using a UV adhesive has been used, a method of peeling by reducing adhesiveness by crosslinking an adhesive interface by UV crosslinking, and a method of heat shrinking a substrate. How to peel off,
A method using heat foaming, a method using water swelling or a water-soluble adhesive, and immersion in water have been proposed.

In the case of (1), one of the adherends needs to be UV-transmissive, which limits the range of use. In the case of (1), if the adhesion of the pressure-sensitive adhesive to the adherend is strong, the peelability is poor, so that it is difficult to obtain a tape having a sufficient adhesive strength, and a heat-shrinkable film (for example, a polystyrene film) is used. The pressure-sensitive adhesive tape used as the tape base has high rigidity, and has problems such as poor followability to a curved surface. However, the adhesive itself has no water resistance and moisture resistance, and its use is limited. Further, it is necessary to treat wastewater used for immersion.

[0005]

For the above reasons, the problem to be solved by the present invention is to further develop the above-mentioned method utilizing hot foaming, so that the problems in the conventional method described above can be eliminated. An object of the present invention is to provide a removable pressure-sensitive adhesive tape which can be peeled efficiently and easily, and which can be recycled without adversely affecting the environment.

[0006]

Acrylic adhesives, urethane adhesives and rubber adhesives generally used for adhesive tapes tend to cause a seizure phenomenon in which the adhesion to an adherend is further increased by heating. In addition, there is a problem that a sufficiently good peeling cannot be obtained even when the thermally expandable fine hollow particles, that is, the thermally expandable fine balloons, which are blended in the adhesive for heating and foaming, are foamed by heating. However, the present inventors have found that the use of the above-mentioned UV pressure-sensitive adhesive hardly causes the baking phenomenon, and that good peeling can be obtained by foaming.

[0007] That is, the means of the present invention for solving the above-mentioned problem is that in the invention of claim 1, the thermal expansion which expands by heating with respect to 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive on the tape base material or release paper. 10-30 hollow fine particles
This is a recyclable heat-removable pressure-sensitive adhesive tape characterized by being coated with a compounded adhesive containing a part by mass and cured with an active energy ray.

According to the second aspect of the present invention, the active energy ray-curable pressure-sensitive adhesive has a number average molecular weight of 3,000 to 100,000.
70 to 98% by mass of the prepolymer of the chemical formula (1)
A mixed prepolymer having a balance of a prepolymer having a number average molecular weight of 1,000 to 100,000 and a chemical formula (2);
2. A recyclable heat-removable pressure-sensitive adhesive tape according to claim 1, wherein 1 to 10% by mass of a photopolymerization initiator is added to 90 to 99% by mass of the mixed prepolymer. It is.

[0009]

## STR3 ## AI- (PI-) nC (1) wherein A: alcohol component having a photosensitive group I: isocyanate group P: polyester diol comprising dibasic acid and diol C: Monoalcohol component n: 3 to 10

[0010]

## STR4 ## AI- (PI-) m-A (2) wherein A: alcohol component having a photosensitive group I: isocyanate group P: polyester diol comprising dibasic acid and diol m: 1-3

Further, the prepolymer of the formula (1) and the prepolymer of the formula (2) are UV adhesives which are cured by irradiation with ultraviolet rays.

According to the third aspect of the present invention, the prepolymers represented by the chemical formulas (1) and (2) are formed by a polyaddition reaction of an isocyanate group of I and a hydroxyl group of A, P or C. 3. The method according to claim 2, wherein
And a recyclable pressure-sensitive adhesive tape which is recyclable by means of (1).

In the invention of claim 4, the thermally expandable fine hollow particles have an expansion ratio of 20 to 100 times and an expansion start temperature of 100 to 150 ° C.
A recyclable pressure-sensitive adhesive tape by recyclable heating and foaming according to any one of the above items.

According to the fifth aspect of the present invention, the compounded pressure-sensitive adhesive is applied to 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive and 10 to 30 parts by mass of the heat-expandable fine hollow body, and to the tackifier resin 0 to 3 by mass.
0 parts by mass, and 0 to 10 parts by mass of a filler are added as optional components. A recyclable heat-foamable pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein the adhesive tape is recyclable. is there.

In the above description, the active energy ray refers to an ultraviolet ray (UV ray), and the active energy ray-curable pressure-sensitive adhesive referred to in the present invention is a pressure-sensitive adhesive that is cured by irradiating ultraviolet rays, that is, a UV pressure-sensitive adhesive. In the present invention, it refers to a UV adhesive compounded in a specific ratio.

[0016]

Embodiments of the present invention will be described.
For 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive, a heat-expandable fine hollow particle which expands by heating is 10 to 3
0 parts by mass are blended to form a blended pressure-sensitive adhesive which is a pressure-sensitive adhesive composition,
This adhesive was applied to a tape substrate, and then irradiated with active energy rays, that is, ultraviolet rays, to cure the adhesive composition to produce an adhesive tape.

Examples of the tape substrate include synthetic resin films such as polyethylene, polypropylene, polystyrene, and polyethylene terephthalate, and nonwoven fabrics, Japanese paper, and metal foils.
Materials generally used for adhesive tapes can be used.
However, a material that does not easily hinder the expansion of the pressure-sensitive adhesive layer due to heat foaming is preferable. Therefore, a non-carrier tape composed of only the pressure-sensitive adhesive layer without a tape substrate is most suitable as the pressure-sensitive adhesive tape of the present invention.

When this non-carrier tape is used, the above-mentioned compounded adhesive is applied on release paper and then cured by irradiation with an active energy ray. In the case of a sheet form, a release paper is further bonded to the other adhesive surface, and in the case of a roll form, it is wound up and completed. Further, the pressure-sensitive adhesive tape of the present invention comprises a single-sided pressure-sensitive adhesive tape or a double-sided pressure-sensitive adhesive tape.

As the active energy ray-curable pressure-sensitive adhesive,
The number average molecular weight is 3,000 to 100,000, preferably 1
70 to 98% by mass of the prepolymer having the structure represented by the chemical formula (1) of 0000 to 50,000, and the remainder having a number average molecular weight of 1,000 to 100,000, preferably 1,000 to 200,000
A prepolymer of the structure of formula (2) of 00, ie 3
A mixed prepolymer consisting of 0 to 2% by mass of a prepolymer having a structure of the chemical formula (2);
The photopolymerization initiator as a catalyst is used in an amount of 1 to 10 based on 99% by mass.
% By mass.

[0020]

## STR5 ## AI- (PI-) nC (1) wherein A: alcohol component having a photosensitive group I: isocyanate group P: polyester diol comprising dibasic acid and diol C: Monoalcohol component n: 3 to 10

[0021]

A- (PI-) m-A (2) wherein A: alcohol component having a photosensitive group I: isocyanate group P: polyester diol comprising dibasic acid and diol m: 1-3

The prepolymers represented by the chemical formulas (1) and (2) are formed by the polyaddition reaction of the isocyanate group of I and the hydroxyl group of A, P or C.

Now, the prepolymer of the formula (1) or (2) will be described in more detail.
Examples of the alcohol component having a photosensitive group of A include (meth)
Examples of the acryloyl group include hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate. Examples of vinyl ethers include hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, and cyclohexyl diacrylate. There is methanol monovinyl ether, and as the epoxide, there is lisidol.

The isocyanate group of I is a non-responsible diisocyanate such as hexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, hydrogenated MDI, or a trimer of these alone or as a mixture. .

Examples of the polyester diol comprising a dibasic acid of P and a diol include dibasic acids such as succinic acid, adipic acid, phthalic acid, dimer acid and hydrogenated dimer acid, and ethylene glycol, propylene glycol, butylene glycol and pentane. Diol, hexane diol, heptane diol, octane diol, nonane diol, decane diol, dimer diol, hydrogenated dimer diol and a polyester diol composed of a diol such as an isomer thereof, and a hydroxycarboxylic acid such as apple in the polyol. Polyester diol incorporating acid, dimethylolpropionic acid, dimethylolbutanoic acid, 1,2-hydroxystearic acid and the like. Further, it is a polyester diol obtained by ring opening such as γ-butyrolactone and ε-caprolactone.
These molecular weights are desirably 500-5000,
More preferably, it is 1000-3000.

The monoalcohol component of C includes methanol, ethanol, propanol, pentanol, hexanol, heptanol, octanol, nonanol,
Decanol, undecanol, dodecanol, tridecanol, octadecanol, and isomers thereof, and hydroxycarboxylic acids such as hydroxyacetic acid, hydroxypropionic acid, hydroxybutanoic acid, azelaic acid, and 1-2-hydroxystearic acid.

Further, as a photopolymerization initiator, when A is a (meth) acryloyl group, 1 to 10 parts by mass, preferably 1 to 3 parts by mass of hydroxycyclohexyl phenyl ketone, 1-phenyl-2-hydroxy-2-methylpropan-1-one,
2,2-dimethoxy-2-phenylacetophenone, benzophenone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 4-
(2-acryloyloxyethoxy) phenyl- (2-
(Hydroxy-2-propyl) ketone, a polymer thereof, or a combination of camphorquinone and a tertiary amine is preferred. Also, A
In other cases, 1 to 10 parts by mass, preferably 2 to 5 parts by mass, of onium such as p-hydroxyphenylbenzylsulfonium salt and p-methoxycarbonyloxyethoxyphenyldimethylsulfonium salt, relative to 100 parts by mass of the prepolymer. It is preferable to use a salt in combination.

The thermally expandable fine hollow particles have an expansion ratio of 20 to
100 times, and the foaming start temperature is 100 to 150 ° C.

The compounded adhesive is 100 parts of an active energy ray-curable pressure-sensitive adhesive, 10 to 30 parts by mass of a heat-expandable fine hollow body, 0 to 30 parts by mass of a tackifier resin, and 0 to 10 parts of a filler.
Parts by weight are added as optional components.

As the tackifying resin, conventionally known resins can be widely used, and may be selected according to the adherend. For example, rosin ester resin, phenol resin, xylene resin, xylene phenol resin, terpene phenol resin, various petroleum resins such as aromatic type, aliphatic-aromatic copolymer type or alicyclic type, coumarone resin, low molecular weight polystyrene type Resins, terpene resins and the like.

The addition amount is preferably from 0 to 30 parts by mass based on 100 parts by mass of the active energy ray-curable pressure-sensitive adhesive. When the amount exceeds 30 parts by mass, the adhesion to the adherend is increased, and it becomes difficult to thermally peel off.

Further, the active energy ray-curable pressure-sensitive adhesive is used in order to improve heat resistance, to make the pressure-sensitive adhesive film tough and easy to peel off, and to make it easy to remove the pressure-sensitive adhesive tape after the heat treatment. , A filler can be optionally added.

As the filler, conventionally known fillers can be used, and examples thereof include calcium carbonate-based, titanium oxide-based, silicic acid-based, and silicic anhydride-based fillers. Increasing the amount of addition deteriorates the transmittance of the active energy ray and causes a curing failure. Therefore, the amount of addition is limited depending on the type of the filler, although it is different. Silica is most preferred as a filler that hardly inhibits curing. In this case, the addition amount is preferably from 0 to 10 parts by mass based on 100 parts by mass of the active energy ray-curable resin. If the amount exceeds 10 parts by mass, the transmittance of active energy rays, that is, UV rays decreases, and a long curing time is required. In addition, the properties of the cured pressure-sensitive adhesive, particularly tackiness, are reduced.

The pressure-sensitive adhesive tape of the present invention is a single-sided or double-sided pressure-sensitive adhesive tape obtained by applying the above-mentioned pressure-sensitive adhesive composition on a tape substrate or release paper, and then irradiating with an active energy ray. In a sheet or roll form.

[0035]

EXAMPLES Next, Tables 1 to 3 show examples of the present invention and comparative examples.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

Prior to the examples, a method of synthesizing a UV adhesive as a prepolymer of the formula (1) to be mixed with the active energy ray-curable adhesive will be described. Synthesis Example 1: UV which is a prepolymer represented by chemical formula (1)
The method for synthesizing the pressure-sensitive adhesive (1) will be described. First, 1400 g of a polyester diol composed of adipic acid and neopentyl glycol and having a hydroxyl value of 56.1, 177.6 g of isophorone diisocyanate, 0.2 g of BHT, and 0.2 g of dibutyltin dilaurate were cooled to a 3 L size equipped with four tubes. After charging in a neck flask and reacting at 80 ° C. for 5 hours, 11.6 g of hydroxyethyl acrylate, 1.4 g of isononanol and 0.2 g of methquinone were added, and the reaction was further carried out for 12 hours. The disappearance of the isocyanate group was confirmed by infrared absorption spectrum, and the reaction was completed. The obtained prepolymer of the chemical formula (1) had a number average molecular weight in terms of styrene of 16,000 by GPC.

Synthesis Example 2 This is a method for synthesizing a UV adhesive (2) which is a prepolymer represented by the chemical formula (2). That is, in Synthesis Example 1 described above, 600 g of a polyester diol composed of adipic acid and neopentyl glycol and having a hydroxyl value of 56.1, and isophorone diisocyanate 88.8.
g, BHT 0.2 g, dibutyltin dilaurate 0.2
The reaction was carried out under the same conditions as in Synthesis Example 1 except that g and 11.6 g of hydroxyethyl acrylate were further added instead of isononal. The obtained prepolymer of the chemical formula (2) had a number average molecular weight in terms of styrene of 8,000 by GPC.

Next, Comparative Examples and Examples of the present invention will be described below in the order of Tables 1 to 3. In all Comparative Examples and Examples, 97% by mass of the mixed prepolymer composed of the UV adhesive (1) and the UV adhesive (2)
The photopolymerization initiator hydroxycyclohexyl phenyl ketone was added in an amount of 3% by mass. However, since the photopolymerization initiator acts as a catalyst, Tables 1 to 3
Not shown.

COMPARATIVE EXAMPLE 1 This was prepared as follows.
V adhesive (1) alone, 20 parts by mass of thermally expandable fine hollow particles (trade name: Expancel 091 DU manufactured by Nippon Philite) per 100 parts by mass of UV adhesive (1). The mixed pressure-sensitive adhesive liquid obtained by adding and mixing is applied on a release paper with a tape thickness of 160 using an applicator.
Apply so as to be ± 5 μm. Then, ultraviolet rays were irradiated from the surface of the applied pressure-sensitive adhesive (irradiation amount: 2000 mj / cm ² ,
(A 2KW metal halide lamp, manufactured by Matsushita Electric Works, Ltd.) and cured to produce a non-carrier adhesive tape.

Comparative Example 2 The procedure of Comparative Example 1 was repeated except that the UV-sensitive adhesive (1) and the UV-sensitive adhesive (2) were used as a mixture of 1 part by mass as a pressure-sensitive adhesive base.

Example 1 The same procedure as in Comparative Example 1 was carried out except that a UV adhesive (1) was used in an amount of 98 parts by mass and a UV adhesive (2) was used in an amount of 2 parts by mass. .

Example 2 The procedure of Comparative Example 1 was repeated except that the UV-sensitive adhesive (1) was 95 parts by mass and the UV-sensitive adhesive (2) was 5 parts by mass. .

Example 3 The procedure of Comparative Example 1 was repeated except that the UV-sensitive adhesive (1) was 90 parts by mass and the UV-sensitive adhesive (2) was 10 parts by mass. .

Example 4 A pressure-sensitive adhesive base was prepared in the same manner as in Comparative Example 1, except that the UV pressure-sensitive adhesive (1) was 80 parts by mass and the UV pressure-sensitive adhesive (2) was 20 parts by weight. .

Example 5: A pressure-sensitive adhesive base was prepared in the same manner as in Comparative Example 1 except that the UV pressure-sensitive adhesive (1) was 70 parts by mass and the UV pressure-sensitive adhesive (2) was 30 parts by weight. .

Comparative Example 3 An adhesive base was prepared in the same manner as in Comparative Example 1 except that the UV adhesive (1) was a 60 parts by mass and the UV adhesive (2) was 40 parts by mass. .

Comparative Example 4 The procedure of Example 5 was repeated, except that the amount of the heat-expandable fine hollow particles was changed to 5 parts by mass.

Example 6 A sample was produced in the same manner as in Example 5, except that the amount of the thermally expandable fine hollow particles was changed to 10 parts by mass.

Example 7 A sample was prepared in the same manner as in Example 5, except that the amount of the thermally expandable fine hollow particles was changed to 30 parts by mass.

Comparative Example 5 The procedure of Example 5 was repeated except that the amount of the thermally expandable fine hollow particles was changed to 40 parts by mass.

Example 8: As a pressure-sensitive adhesive base, 90 parts by weight of the UV pressure-sensitive adhesive (1) and 10 parts by weight of the UV pressure-sensitive adhesive (2) were mixed, and 20 parts by weight of the heat-expandable fine hollow particles were added thereto. And 20 parts by mass of a tackifying resin (trade name: Escolets 5380, manufactured by Tonex Corporation, 50% toluene solution of hydrogenated alicyclic hydrocarbon), and mixed on a release paper. After applying with 9
Evaporate the solvent in an oven at 0 ° C. for 2 minutes. next,
Irradiate ultraviolet rays from the surface of the compounded adhesive (irradiation amount 2000mj
/ Cm ² , an ultraviolet curing device manufactured by Matsushita Electric Works: 2KW metal halide lamp) and cured to produce a non-carrier adhesive tape. The tape thickness was 160 ± 5 μm.

Comparative Example 6 The procedure of Example 8 was repeated except that the amount of the tackifier resin was changed to 60 parts by mass.

Comparative Example 7: Production was carried out in the same manner as in Example 8 except that the amount of the tackifier resin was changed to 80 parts by mass.

Example 9: As a pressure-sensitive adhesive base, 90 parts by weight of the UV pressure-sensitive adhesive (1) and 10 parts by weight of the UV pressure-sensitive adhesive (2) were mixed, and 20 parts by weight of the thermally expandable fine hollow particles were added thereto. , 20 parts by mass of a tackifying resin (trade name: Escolets 5380, manufactured by Tonex Corporation, 50% toluene solution of hydrogenated alicyclic hydrocarbon), filler (trade name: Aerosil R)
972, silica manufactured by Nippon Aerosil Co.) was prepared in the same manner as in Example 8, except that a compounded adhesive obtained by adding and mixing 5 parts by mass was used.

Example 10 The procedure of Example 9 was repeated except that the filler was changed to 10 parts by mass.

Example 11 The procedure of Example 9 was repeated, except that the filler was changed to 20 parts by mass.

Comparative Example 8: A compounded pressure-sensitive adhesive obtained by adding 20 parts by mass of a fine hollow body made of thermal expansion to an acrylic solvent-type pressure-sensitive adhesive was coated on release paper. The solvent was volatilized in an oven at 90 ° C. to produce a non-carrier adhesive tape. The tape thickness was 160 ± 5 μm.

Comparative Example 9 A compounded pressure-sensitive adhesive obtained by adding 20 parts by mass of a fine hollow body made of thermal expansion to a rubber-based solvent-type pressure-sensitive adhesive was coated on release paper. The solvent was volatilized in an oven at 90 ° C. to produce a non-carrier adhesive tape. The tape thickness was 160 ± 5 μm.

Various evaluation test methods in Tables 1 to 3 will be described below. 180 ° peel strength: SUS304 plate (thickness: 2 mm) (described as “ST” in the table) and polystyrene plate (thickness: 2 m)
m) A pressure-sensitive adhesive tape to be subjected to a test is pressed on a 25 mm width JIS 2 kg roll (described as “styrene” in the table). A polyester film (thickness: 25 μm) is attached to the other pressure-sensitive adhesive surface. 72 hours after crimping, 23 ± 2 ° C
And measure the 180 ° peel strength after standing. The pulling speed is 300 mm / min.

Shear strength: SUS304 plate (2 mm thick)
(Described as “ST” in the table) and a polystyrene plate (thickness 2).
mm) (described as “styrene” in the table) are adhered to each other with an adhesive tape to be subjected to a test so as to have an adhesion area of 25 mm × 25 mm, and pressed with a 10 kg roll. The shear strength after standing at 23 ± 2 ° C. for 72 hours after the pressure bonding is measured. The pulling speed is 50 mm / min.

Holding force: A test specimen similar to the shear test was prepared, suspended at 60 ° C. under a load of 9.81 N, and the time required for the weight to fall was measured.

Thermal peelability: SUS304 plate (2 mm thick)
(Described as “ST” in the table) and a polystyrene plate (thickness 2).
mm) (described as “styrene” in the table) are adhered to each other with an adhesive tape to be used for the test, and pressed with a 10 kg roll. After standing at 23 ± 2 ° C for 72 hours after crimping, 150 ° C
In an oven for 20 minutes and observe the state of the bonded portion.

In the table, ◎ indicates that the adherend and the tape spontaneously peeled off,
Indicates separation. In the table, ○ indicates that the adherend and the tape did not peel off spontaneously, but could be easily separated. In the table, △ indicates that separation can be achieved by prying between the adherends with a screwdriver or the like. In the table, x indicates that the tape adheres to the adherend and does not peel off easily even if it is pryed open with a screwdriver or the like. If it is forcibly peeled off, the tape is completely broken and remains on the adherend.

As shown in the above table, Comparative Example 1, Comparative Example 2 and Comparative Example 7 have a thermal peeling property of Δ and need to be squeezed with a screwdriver, which is not sufficiently suitable for the purpose of the present invention. In Examples 1 and 6, the thermal releasability was ○, and it did not spontaneously separate, but could be easily separated. In Comparative Example 5, the heat-expandable fine-grained hollow body was as small as 5 parts by mass. Comparative Example 3 and Comparative Example 5 have excellent thermal peelability.
But excellent in peeling strength and shear strength under normal conditions. In Comparative Example 6, the tackifier was added in an amount not less than the amount added in the present invention, and the heat peelability was slightly low.
And inferior to Example 8 in which the components other than the tackifier were the same. Comparative Example 8 further contains a tackifier and has a thermal peeling property of Δ and cannot be put to practical use. Comparative Examples 8 and 9 contain an appropriate amount of heat-expandable fine hollow particles because the adhesive is an acrylic or rubber-based adhesive unlike the UV adhesive in the present invention. Even if the fine hollow particles are foamed, sufficiently good peeling cannot be obtained, and the thermal peelability is x, so that they cannot be put to practical use.

[0068]

As described above, according to the present invention, the peeling strength, shear strength and holding power are not less than those of the conventional adhesive tape, but the seizure phenomenon is caused by heating. The adherend and the tape can be easily separated or spontaneously peeled off without further increasing the adhesion to the adherend. Therefore, the members adhered using the pressure-sensitive adhesive tape of the present invention can be easily separated and separated again, so that the adherend and the pressure-sensitive adhesive tape can be separately separated and collected and treated, so that they can be recycled without harming the environment. Therefore, the pressure-sensitive adhesive tape of the present invention has excellent effects as compared with conventional pressure-sensitive adhesive tapes.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Ikeda 5-2-2-5 Nishikujo-cho, Nara-shi F-term in Kyoeisha Chemical Co., Ltd. Nara Research Laboratory 4J004 AA10 AA14 AB06 CA02 CA04 CA06 CA08 CC02 DB03 EA01 FA08 4J027 AG03 AG09 AG24 AG33 AJ01 AJ02 BA01 CA36 CA39 CB10 CC03 CD09 4J040 EF111 FA221 GA05 GA20 HB18 HC03 HD18 JA01 JB07 KA11 LA06 LA08 MA10 NA05 NA12 NA15 PA32

Claims (5)

[Claims] 1. A mixed pressure-sensitive adhesive containing 10 to 30 parts by mass of a heat-expandable fine hollow body which expands by heating with respect to 100 parts by mass of an active energy ray-curable pressure-sensitive adhesive is applied to a tape base material or release paper. A recyclable adhesive tape formed by heating and foaming, which is hardened by active energy rays. 2. The active energy ray-curable pressure-sensitive adhesive comprises 70 to 98% by mass of a prepolymer of the formula (1) having a number average molecular weight of 3,000 to 100,000, and the remainder has a chemical formula (2) of a number average molecular weight of 1,000 to 100,000. 2. The recycling method according to claim 1, wherein a mixed prepolymer comprising the prepolymer of (1) and 1 to 10% by mass of a photopolymerization initiator is added to 90 to 99% by mass of the mixed prepolymer. Adhesive tape that is removable by heating and foaming. ## STR1 ## AI- (PI-) nC (1) wherein A: alcohol component having a photosensitive group I: isocyanate group P: polyester diol comprising dibasic acid and diol C: Monoalcohol component n: 3 to 10 A-I- (P-I-) mA (2) where A: alcohol component having a photosensitive group I: isocyanate group P: dibasic acid And polyester diols consisting of diols m: 1 to 3 3. The prepolymers of formulas (1) and (2) are characterized in that the isocyanate group of I and the hydroxyl group of A, P or C are bonded by a polyaddition reaction. The recyclable pressure-sensitive adhesive tape according to claim 2, which is recyclable. 4. The heat-expandable fine-particle hollow body has an expansion ratio of 20.
The removable pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive tape has a foaming start temperature of 100 to 150 ° C. 5. The compounded adhesive comprises 100 parts by mass of an active energy ray-curable pressure-sensitive adhesive, 10 to 30 parts by mass of a heat-expandable fine-grained hollow body, 0 to 30 parts by mass of a tackifier resin, and 0 parts by mass of a filler.
The removable pressure-sensitive adhesive tape by recyclable heating and foaming according to any one of claims 1 to 4, wherein 10 to 10 parts by mass is added as an optional component.