JP6120123B2 - Double-sided adhesive tape, article and separation method - Google Patents

Description

  The present invention is applied to an adherend and fixed between articles, and is pasted by an easily dismantleable double-sided adhesive tape that can be easily released after a certain period of time, and the double-sided adhesive tape. The present invention relates to a method for separating two or more adherends combined.

  Adhesive tape is a bonding means with excellent workability and high bonding reliability. It displays parts fixing applications in various industrial fields such as OA equipment, IT equipment, home appliances, automobiles, temporary fixing of parts, and product information. Used for labeling applications. In recent years, from the viewpoint of protecting the global environment, there is an increasing demand for recycling and reuse of used products in these industrial fields. When recycling and reusing various products, it is necessary to fix the parts and peel off the adhesive tape used for the labels. However, since the adhesive tape is provided at various locations in the product, Reduction of the work cost by a removal process is desired.

  As a pressure-sensitive adhesive tape that can be peeled relatively easily, for example, a pressure-sensitive adhesive member having two or more pressure-sensitive adhesive layers having different adhesive forces is disclosed (see Patent Document 1). The adhesive tape is obtained by bonding the adherend through a weak adhesive layer in an adhesive member having an adhesive layer having a superposed structure, thereby easily fixing the adherend and making the weak adhesive layer a release surface. It is an adhesive member that realizes easy disassembly.

  However, since the adhesive member has a plurality of adhesive layers as essential components, there is a problem in that the manufacturing cost increases. Moreover, since it is the structure by which adhesion | attachment with a to-be-adhered body is performed by a weak adhesion layer, there exists a restriction | limiting in improving adhesive force, and the expansion | deployment to the use which fixes an article | item firmly was difficult.

Japanese Patent Laid-Open No. 10-140093

  The problem to be solved by the present invention can be used for attaching to an adherend or fixing two or more adherends, and can be easily disassembled when separating the two or more adherends. Is to provide a simple double-sided adhesive tape.

  The present invention relates to a double-sided pressure-sensitive adhesive tape characterized by having a pressure-sensitive adhesive layer on both sides of an easily disintegrable layer containing a binder and thermally expandable microspheres, directly or via another layer.

  The present invention also relates to an article having a configuration in which two or more adherends are bonded by the double-sided pressure-sensitive adhesive tape.

  The present invention also relates to a method for separating two or more adherends constituting the article by heating the easily disintegrable layer constituting the article and expanding the thermally expandable microspheres.

  The double-sided pressure-sensitive adhesive tape of the present invention can be attached to an adherend, can firmly bond two or more adherends, and dismantle the article by eliminating the adhesion between the adherends. In this case, the two or more adherends can be easily separated by heating.

  According to the method for producing a double-sided pressure-sensitive adhesive tape of the present invention, the double-sided pressure-sensitive adhesive tape of the present invention can be produced.

  According to the separation method of the present invention, bonding of adherends can be easily separated.

It is sectional drawing which shows an example of embodiment of the double-sided adhesive tape which concerns on this invention. It is sectional drawing which shows an example of embodiment of the double-sided adhesive tape which concerns on this invention. It is a figure explaining an example of an embodiment of a manufacturing method of a double-sided adhesive tape concerning the present invention. It is a figure explaining an example of an embodiment of an adhesion method concerning the present invention. It is a figure explaining an example of embodiment of the separation method concerning the present invention. It is the figure which showed the mode of separation of the adherend typically. It is sectional drawing which shows an example of embodiment of the isolation | separation method which concerns on this invention. It is a figure explaining the structure of the double-sided adhesive tape of Example 1, the manufacturing method of the double-sided adhesive tape of Comparative Example 1, and the double-sided adhesive tape of Example 1, and the double-sided adhesive tape of Comparative Example 1. It is a figure explaining the method of the dismantling test in an Example.

≪Double-sided adhesive tape≫
The double-sided pressure-sensitive adhesive tape of the present invention is characterized by having a pressure-sensitive adhesive layer directly or via another layer on both surfaces of an easily dismantled layer containing a binder and thermally expandable microspheres.

  Hereinafter, an example of the embodiment of the double-sided pressure-sensitive adhesive tape of the present invention will be described.

<First Embodiment>
FIG. 1 is an example of an embodiment of a double-sided pressure-sensitive adhesive tape according to the present invention. The double-sided pressure-sensitive adhesive tape 1 has pressure-sensitive adhesive layers 20 and 21 on both sides of an easily dismantled layer 10 containing a binder 11 and thermally expandable microspheres 12. Release sheets 30 and 31 may be laminated on the pressure-sensitive adhesive layers 20 and 21, respectively.

Hereinafter, each structure of a double-sided adhesive tape is demonstrated.
[Easily dismantled layer]
The easily dismantled layer 10 contains a binder 11 and thermally expandable microspheres 12. The easily dismantled layer is a layer that is broken by a peeling stress such as separating the adherends when separating two or more adherends bonded together by the double-sided adhesive tape.

As the binder, a binder that can be easily disassembled by the expansion force of the thermally expandable microspheres can be used. Moreover, it is preferable to use what is thermoplastic as said binder. Here, thermoplastic and has a storage elastic modulus _{G 23} as measured by dynamic viscoelasticity spectrum at 1Hz and 23 ° C. of the binder in the range of ^{1.0 × 10 3 ~5.0 × 10 7} Pa storage modulus _{G 120} which is measured by a dynamic viscoelasticity spectrum at 1Hz and 120 ° C. refers to those in a range of ^{1.0 × 10 2 ~5.0 × 10 6} Pa.

In a normal state, when the adherends are firmly bonded to each other by the double-sided pressure-sensitive adhesive tape of the present invention, the storage elastic modulus measured by a dynamic viscoelastic spectrum at 1 Hz and 23 ° C. of the binder constituting the easily dismantled layer. it is preferred that G ₂₃ uses what is ^{1.0 × 10 3 ~5.0 × 10 7} Pa, more is possible to use those which is ^{5.0 × 10 3 ~5.0 × 10 6} Pa Preferably, it is more preferable to use what is 5.0 * 10 < ³ > -1.0 * 10 < ⁶ > Pa, It is especially preferable to use what is 1.0 * 10 < ⁴ > -1.0 * 10 < ⁶ > Pa. preferable.

Further, in order to easily separate the adherends by heating, the storage elastic modulus G ₁₂₀ measured by a dynamic viscoelastic spectrum at 1 Hz and 120 ° C. of the binder constituting the easily dismantled layer is 1.0 × 10 10. it is more preferable that the use of what is ^{2 ~5.0} × ¹⁰ 6 Pa to use a preferably ^{5.0 × 10 2 ~1.0 × 10 6} Pa, 5.0 × 10 2 ~ more preferable to use what is 5.0 × ¹⁰ 5 Pa, it is particularly preferable to use one which is ^{5.0 × 10 2 ~5.0 × 10 5} Pa.

The storage elastic modulus G ₁₂₀ of the binder in the easy dismantling layer, it is preferable that the smaller than the storage modulus G _23.

The storage modulus G ₂₃ and G ₁₂₀ refers to the results of the measurement for test piece formed by using a binder which constitutes the Disassembly layer. The test piece does not contain thermally expandable microspheres. The thickness of the test piece is 2 mm. The test piece can be obtained by, for example, applying a binder contained in the easily dismantled layer on the sheet.

Storage modulus G ₂₃ and G _120, using a commercial viscoelastic tester, can be measured by the method described in the examples below.

  The thickness of the easily dismantled layer is preferably 5 μm to 80 μm, more preferably 5 μm to 60 μm, and still more preferably 10 μm to 50 μm. The thickness of the easily dismantled layer is an average value obtained by measuring the thicknesses of 5 locations randomly selected in the thickness direction of the easily dismantled layer. When the thickness of the easily dismantled layer is within the above range, it is possible to form an easily dismantled layer that is easy to form a layer and is excellent in easy disassembly.

  As the binder contained in the easily dismantled layer, for example, a thermoplastic resin is preferably used because it is easily softened by heat and easily disassembled.

  Examples of the thermoplastic resin include urethane resins such as polyurethane (PU) and thermoplastic polyurethane (TPU); polycarbonate (PC); polyvinyl chloride (PVC) and vinyl chloride such as vinyl chloride-vinyl acetate copolymer resin. Resins such as polyacrylic acid, polymethacrylic acid, polymethyl acrylate, polymethyl methacrylate (PMMA), polyethyl methacrylate, etc .; polyethylene terephthalate (PET), polybutylene terephthalate, Polyester resins such as polytrimethylene terephthalate, polyethylene naphthalate and polybutylene naphthalate; Polyamide resins such as nylon (registered trademark); Polystyrene (PS), Imido-modified polystyrene, Acrylonitrile butadiene, Styrene (ABS) resin, imide ABS resin, styrene-acrylonitrile copolymer (SAN) resin, polystyrene resins such as acrylonitrile, ethylene-propylene-diene, styrene (AES) resin, polyethylene (PE) resin, polypropylene (PP) resin, cycloolefin resin, etc. Olefin resins; Cellulosic resins such as nitrocellulose and cellulose acetate; Silicone resins; Thermoplastic resins such as fluororesins, Styrenic thermoplastic elastomers, Olefin thermoplastic elastomers, Vinyl chloride thermoplastic elastomers, Urethane heat Examples include thermoplastic elastomers such as plastic elastomers, ester-based thermoplastic elastomers, and amide-based thermoplastic elastomers.

  Among these thermoplastic resins, among them, styrene thermoplastic elastomer, olefin thermoplastic elastomer, vinyl chloride thermoplastic elastomer, ester thermoplastic elastomer, urethane thermoplastic elastomer, amide thermoplastic elastomer or acrylic It is preferable to use a styrene resin or the like, and it is particularly preferable to use a styrene thermoplastic elastomer or an acrylic resin.

  Examples of the styrenic thermoplastic elastomer include styrene-based diblock copolymers such as styrene-ethylene-butylene copolymer (SEB); styrene-butadiene-styrene copolymer (SBS), and hydrogenated SBS (styrene). -Ethylene-butylene-styrene copolymer (SEBS)), styrene-isoprene-styrene copolymer (SIS), hydrogenated product of SIS (styrene-ethylene-propylene-styrene copolymer (SEPS)), styrene-isobutylene -Styrene-based triblock copolymer such as styrene copolymer (SIBS); Styrene-based tetrablock copolymer such as styrene-butadiene-styrene-butadiene (SBSB); Styrene-butadiene-styrene-butadiene-styrene (SBSBS) Styrene pentablots such as Copolymers; Styrenic multi-block copolymers having more than these repeating units; Hydrogenated products obtained by hydrogenating ethylenic double bonds of styrene random copolymers such as styrene-butadiene rubber (SBR); Can be mentioned. A commercially available styrene thermoplastic elastomer may be used.

  As the styrenic thermoplastic elastomer, it is possible to use a mixture of the styrene triblock copolymer and the styrene diblock copolymer, the storage elastic modulus at 23 ° C. and the storage elastic modulus at 120 ° C., It has a value obtained by dividing the storage elastic modulus at 23 ° C. by the storage elastic modulus measured at 120 ° C. As a result, two or more adherends are firmly bonded under a room temperature region of approximately 23 ° C. It is preferable to obtain an adhesive tape that can be easily separated from two or more adherends by being heated to about 120 ° C., and the styrenic diblock copolymer is added to the entire styrenic thermoplastic elastomer. On the other hand, it is more preferable to use what is contained in the range of 10% by mass to 90% by mass, and use in the range of 15% by mass to 80% by mass. Preferably the, and particularly preferably used in the range of 20 wt% to 75 wt%.

  As the styrenic thermoplastic elastomer, one having a weight average molecular weight in the range of 10,000 to 800,000 is preferably used in order to further improve the dismantling property by heating. It is more preferable to use those having a weight average molecular weight of 1, and it is more preferable to use those having a weight average molecular weight in the range of 150,000 to 450,000.

  As said acrylic resin, what is obtained by superposing | polymerizing the monomer containing an alkyl (meth) acrylate can be used, for example.

  As the alkyl (meth) acrylate, a (meth) acrylate having an alkyl group having 4 to 12 carbon atoms is preferably used. Specifically, butyl (meth) acrylate, isooctyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate or the like is preferably used, and butyl acrylate and 2-ethylhexyl acrylate are preferably used alone or in combination.

  In addition to those described above, acrylonitrile, (meth) acrylic acid, maleic anhydride, acrylamide, itaconic acid, styrene, vinyl acetate and the like can be used as the monomer.

  The thermally expandable microspheres contained in the easily dismantled layer can expand under the influence of heat. Specifically, as the thermally expandable microspheres, those having a thermal expansion coefficient at 120 ° C. of 150% or more are preferably used, and those having a thermal expansion coefficient at 120 ° C. of 170% or more are used. More preferably, the one having a coefficient of thermal expansion at 120 ° C. of 200% or more is further preferred, the one having a coefficient of thermal expansion at 120 ° C. of 220% or more is particularly preferred, and 250% or more It is particularly preferable to use a material that is easy to disassemble the easily dismantled layer, and as a result, the adherends can be easily separated from each other. The upper limit of the expansion coefficient is not particularly limited, but is preferably approximately 5000%. In addition, the said thermal expansion coefficient points out the value calculated with the following method.

  First, 1 g of thermally expandable microspheres (non-expanded) is placed in a volumetric flask and the true specific gravity is measured by a water displacement method. Next, 1 g of the thermally expandable microspheres is placed in a gear type oven and heated at 120 ° C. for 2 minutes to expand.

  Next, the expanded microspheres are placed in a volumetric flask and the true specific gravity is measured by a water displacement method.

  The ratio of the true specific gravity of the thermally expandable microsphere before expansion to the true specific gravity of the microsphere after thermal expansion was calculated and multiplied by 100 to obtain the coefficient of thermal expansion.

  The expansion start temperature of the thermally expandable microsphere is not particularly limited, but is preferably 80 ° C. or higher, more preferably 85 ° C. to 120 ° C., and 90 ° C. to 120 ° C. for easy disassembly. It is more preferable to separate them without causing expansion when the layers are formed and without causing damage to two or more adherends due to heat. The “expansion start temperature of the thermally expandable microsphere” is obtained by using a thermal analyzer (“TMA / SS6100”, manufactured by SII / Nanotechnology Co., Ltd.), and the expansion method (load: 0.1N, probe: 3 mmφ, temperature increase rate: 5 ° C./min), the temperature of the thermally expandable microspheres started to expand.

  The maximum expansion temperature of the thermally expandable microsphere is not particularly limited, but is preferably 90 ° C. or higher, preferably 90 ° C. to 180 ° C., and 100 ° C. or higher to 150 ° C. is 2 or higher. It is more preferable to separate them without causing damage to the adherend due to heat. The above-mentioned “maximum expansion temperature” uses a thermal analyzer (“TMA / SS6100”, manufactured by SII / Nanotechnology Co., Ltd.), and an expansion method (load: 0.1 N, probe: This is the temperature at which the expansion of the thermally expandable microspheres is maximized when evaluated at 3 mmφ and the heating rate of 5 ° C./min. Note that the thermally expandable microspheres heated to a temperature higher than the maximum expansion temperature usually contract and reduce the expansion rate, and therefore it is preferable not to heat to a temperature higher than the maximum expansion temperature.

  When producing the thermally expandable microspheres, it is difficult to make all the wall thickness of the capsule used for the production, the content of the gasified substance, etc. uniform, so the expansion start temperature and the maximum expansion The temperature usually has a certain range.

  The particle size of the thermally expandable microspheres (before expansion) is not particularly limited, but when heated, the dismantling property of the easy dismantling layer is further improved and the thinning of the dismantling layer and the double-sided adhesive tape is realized. In doing so, it is preferably in the range of 1 μm to 50 μm, more preferably in the range of 3 μm to 30 μm, and still more preferably in the range of 5 μm to 20 μm.

  The thermally expandable microspheres are usually a collection of particles having different particle sizes. Therefore, distribution (particle size distribution) is obtained when the particle diameter of the thermally expandable microsphere is measured. In the present invention, the particle size (before expansion) of the thermally expandable microsphere was obtained by performing measurement by a laser diffraction scattering method 10 times using a particle size distribution measuring device “Mastersizer 2000” manufactured by Malvern. The maximum value and the minimum value of 10 local maximum values based on 10 particle size distributions are used to represent the range. Specifically, the maximum value of 10 local maximum values based on 10 particle size distributions obtained by measuring the particle size (before expansion) of the thermally expandable microspheres 10 times by the above method is 15 μm, and the minimum When the value is 9 μm, the particle diameter (before expansion) of the thermally expandable microsphere is represented as 9 μm to 15 μm.

  As the heat-expandable microspheres, for example, those containing a substance that is gasified by heat in an elastic capsule can be used.

  As the substance that can be gasified by heat, it is preferable to use a substance that can be gasified by being heated to about 80 ° C. to 150 ° C., specifically, butane, isobutane, propane, isopropane, isopentane, isooctane, etc. More preferably, is used.

  As the capsule having elasticity, for example, a capsule composed of softening when heated to about 90 ° C. to 150 ° C. can be used. Specifically, vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol And capsules composed of polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone and the like.

  The heat-expandable microspheres can be produced by a known and common method such as a coacervation method or an interfacial polymerization method.

  Examples of the thermally expandable microsphere include “Matsumoto Microsphere” (trade name, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), “Microsphere Expandel” (trade name, manufactured by Nippon Philite Co., Ltd.), “ Commercial products such as “Die Form” (trade name, manufactured by Dainichi Seika Kogyo Co., Ltd.) can also be used.

  The content (blending amount) of the heat-expandable microspheres is based on 100 parts by weight of the binder contained in the easy-dismantling layer in order to achieve both good adhesion to the pressure-sensitive adhesive layer and easy disassembly. It is preferably 1 to 100 parts by mass, more preferably 3 to 50 parts by mass, and still more preferably 5 to 30 parts by mass.

[Adhesive layer]
The pressure-sensitive adhesive layers 20 and 21 are layers that adhere to the adherend. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layers 20 and 21 includes a natural rubber polymer, a synthetic rubber polymer, an acrylic polymer, a silicone polymer, a urethane polymer, a vinyl ether polymer, and the like. Can be used. Examples of the form of the pressure-sensitive adhesive include aqueous systems such as solvent-based, emulsion-type pressure-sensitive adhesives, and water-soluble pressure-sensitive adhesives, and solventless systems such as hot-melt pressure-sensitive adhesives, UV-curable pressure-sensitive adhesives, and EB-curable pressure-sensitive adhesives. .

  The pressure-sensitive adhesive layers 20 and 21 preferably contain an acrylic copolymer. An acrylic copolymer is a copolymer of (meth) acrylic acid that imparts hydrophilicity and other monomers copolymerizable therewith, and is obtained by reacting (meth) acrylic acid with vinyl ether. (Meth) acrylate etc. are mentioned.

  The thickness of the pressure-sensitive adhesive layer is preferably 5 μm to 100 μm, more preferably 10 μm to 80 μm, and still more preferably 30 μm to 70 μm. It is preferable for the thickness of the pressure-sensitive adhesive layer to be in the above range because layer formation is easy and adhesion between adherends is excellent.

  The pressure-sensitive adhesive layers 20 and 21 may contain a tackifier resin, a crosslinking agent, other additives, and the like as necessary.

  As the tackifier resin, for the purpose of adjusting the strong adhesion of the pressure-sensitive adhesive layer, for example, rosin tackifier resin, polymerized rosin tackifier resin, polymerized rosin ester tackifier resin, rosin phenol tackifier Examples thereof include a resin, a stabilized rosin ester tackifier resin, a disproportionated rosin ester tackifier resin, a terpene tackifier resin, a terpene phenol tackifier resin, and a petroleum resin tackifier resin.

  For the purpose of improving the cohesive strength of the pressure-sensitive adhesive layer, the crosslinking agent may be a known isocyanate-based crosslinking agent, epoxy-based crosslinking agent, aziridine-based crosslinking agent, polyvalent metal salt-based crosslinking agent, metal chelate-based crosslinking agent. Keto-hydrazide crosslinking agents, oxazoline crosslinking agents, carbodiimide crosslinking agents, silane crosslinking agents, glycidyl (alkoxy) epoxysilane crosslinking agents, and the like can be used.

  Examples of the additive include a base for adjusting pH (such as aqueous ammonia), an acid, a foaming agent, a plasticizer, a softening agent, an antioxidant, as long as the desired effect of the present invention is not inhibited as necessary. Fillers such as glass and plastic fibers, balloons, beads, metal powders, colorants such as pigments and dyes, pH adjusters, film formation aids, leveling agents, thickeners, water repellents, antifoaming agents, etc. The known materials can be optionally added to the pressure-sensitive adhesive. Moreover, you may add an acid catalyst and an acid generator.

  The acid catalyst and the acid generator can be used for the purpose of imparting disassembly by external stimulation of light or heat, for example. As the acid catalyst and the acid generator, those exemplified as those usable for the easily dismantled layer can be used.

  As said adhesive which can be used for formation of the said adhesive layer, what maintains a solvent can be used when maintaining favorable coating workability | operativity etc. As the solvent, for example, toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, hexane and the like can be used. Further, when an aqueous adhesive is used as the adhesive, water or an aqueous solvent mainly composed of water can be used as the solvent.

  Examples of the release sheets 30 and 31 include glassine paper, kraft paper, clay coat paper, paper laminated with a film such as polyethylene, paper coated with a resin such as polyvinyl alcohol or an acrylate copolymer, polyester, polypropylene, and the like. And those obtained by applying a fluororesin or silicone resin as a release agent to the synthetic resin film.

  The pair of pressure-sensitive adhesive layers of the double-sided pressure-sensitive adhesive tape of the present embodiment may have the same configuration or different configurations.

  Since the double-sided pressure-sensitive adhesive tape of this embodiment contains thermally expandable microspheres in the easily dismantled layer, the softening of the binder contained in the easily dismantled layer and the expansion of the thermally expandable microspheres are caused by heating. As a result, the adhesion between adherends can be disassembled with a weaker force than when an easily dismantled layer that does not contain a thermally expandable filler is used.

<Second Embodiment>
FIG. 2 is an example of an embodiment of a double-sided pressure-sensitive adhesive tape according to the present invention. The double-sided pressure-sensitive adhesive tape 2 has pressure-sensitive adhesive layers 20 and 21 on both sides of the easy-disassembly layer 10 containing the binder 11 and the thermally expandable microspheres 12, and both between the easy-disassembly layer and the pressure-sensitive adhesive layer. The base films 40 and 41 are provided. Release sheets 30 and 31 may be laminated on the pressure-sensitive adhesive layers 20 and 21, respectively.

  As for the double-sided adhesive tape of 2nd Embodiment, the double-sided tape of said <1st Embodiment> has further base film 40, 41 in both between the said easily dismantled layer and the said adhesive layer. It is. The description of points that are the same as those in the first embodiment will be omitted.

  Examples of the base film include polyolefin (for example, polypropylene, polyethylene), polyester (for example, polyethylene terephthalate, polyethylene naphthalate), polystyrene, acrylonitrile-butadiene-styrene resin (ABS resin), polycarbonate, polyimide film, polychlorination. Nonwoven fabrics, papers, cloths, metal foils and the like obtained by using plastic films made of vinyl, nylon, polyvinyl alcohol, etc., pulp, rayon, Manila hemp, acrylonitrile, nylon, polyester, and the like.

  The base film serves as a support when the double-sided adhesive tape is peeled off from the adherend after the adherends bonded with the double-sided adhesive tape are disassembled and the easily dismantled layer is broken. obtain.

  Therefore, the adhesiveness between the base film and the other layers of the double-sided pressure-sensitive adhesive tape (in this embodiment, the adhesiveness between the base films 40 and 41 and the adhesive layers 20 and 21) and the strength as a support are compatible. Since it is easy to do, a plastic film is preferable and a polyester film is more preferable.

  Further, for the purpose of improving the adhesion between the base film and the pressure-sensitive adhesive layer, a corona treatment, a plasma treatment, an anchor coat treatment or the like may be applied to one or both sides of the base film.

  In the double-sided pressure-sensitive adhesive tape of this embodiment, when heated, the binder contained in the easy-dismantling layer is softened, and the thermally expandable microspheres are expanded, so that the cohesive force of the easy-dismantling layer is dramatically increased. Since it lowers and is easily disassembled, the double-sided pressure-sensitive adhesive tape is disassembled with little force after the heating, and two or more adherends can be separated from each other.

  Moreover, the double-sided pressure-sensitive adhesive tape of the second embodiment further has a base film between the easily dismantled layer and the pressure-sensitive adhesive layer. In the disassembled double-sided pressure-sensitive adhesive tape, the residue of the double-sided pressure-sensitive adhesive tape may remain on the adherend. In particular, in a double-sided pressure-sensitive adhesive tape having a fragile layer that is easily disassembled, such as an easy-disassembly layer, it may be difficult to remove the residue of the double-sided pressure-sensitive adhesive tape remaining on the adherend. However, since the double-sided pressure-sensitive adhesive tape of this embodiment further has a base film between the easily dismantled layer and the pressure-sensitive adhesive layer, the double-sided pressure-sensitive adhesive tape disassembled by catching and pulling the base film part, etc. The entire residue can be easily removed from the adherend.

  In the present embodiment, the double-sided pressure-sensitive adhesive tape comprising the easily dismantled layer 10 containing the binder 11 and the heat-expandable microspheres 12, the pressure-sensitive adhesive layers 20, 21, the base film 40, 41, and the release sheets 30, 31. However, in addition to the above layer structure, it may further have an arbitrary layer structure.

  For example, as the double-sided pressure-sensitive adhesive tape of the present invention, a foam (foam) is used between the base films 40 and 41 and the pressure-sensitive adhesive layers 20 and 21 or between the base films 40 and 41 and the easily dismantled layer 10. A material having a material layer can be used. The foam layer serves as a cushion, and can provide cushioning properties to the double-sided pressure-sensitive adhesive tape having the foam layer.

  The double-sided pressure-sensitive adhesive tape of the present invention can be suitably used, for example, for adhesion between a rigid body and a rigid body as an adherend and separation between the rigid body and the rigid body. Examples of the rigid adherend include a metal plate, a metal casing, a metal cover, a glass plate, and a plastic plate. The two or more adherends bonded by the double-sided pressure-sensitive adhesive tape of the present invention may be the same kind of adherends or different kinds of adherends. The adherends bonded and separated by the double-sided pressure-sensitive adhesive tape of the present invention may be the same kind of adherends or different kinds of adherends.

  The double-sided pressure-sensitive adhesive tape of the present invention can be easily disassembled by heating when separating between members during reuse or recycling. For this reason, it can be suitably used as a double-sided pressure-sensitive adhesive tape that fixes parts of various products in industrial applications such as automobiles, building materials, OA, and home appliance industries. The work efficiency is also good when separating a large amount of parts during reuse or recycling, or when removing a large amount of labels.

  The double-sided pressure-sensitive adhesive tape of the present invention can be disassembled at a relatively low heating temperature. Therefore, in particular, it can be suitably used as a double-sided pressure-sensitive adhesive tape for fixing an electrical product such as a mobile phone, a video display device, a computer or the like that is likely to be deteriorated due to heat.

≪Method for manufacturing double-sided adhesive tape≫
The method for producing a double-sided pressure-sensitive adhesive tape of the present invention comprises preparing an easily disassembled layer containing a binder and thermally expandable microspheres, and bonding one adhesive layer to one side of the easily dismantled layer, and thereafter The other pressure-sensitive adhesive layer is bonded to the other side of the layer.

  FIG. 3 is an example of an embodiment of a method for producing a double-sided pressure-sensitive adhesive tape according to the present invention. First, a mixture of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, the binder constituting the easy-disassembly layer, and the thermally expandable microspheres is prepared. Next, as shown in FIG. 3, using an applicator, an adhesive is applied onto the release sheets 32 and 34 to form the adhesive layers 20 and 21, and a binder and thermally expandable microspheres are formed on the release sheet 33. The easily dismantled layer 10 is formed by applying the mixture. Next, after the pressure-sensitive adhesive layer 20 is bonded to one surface of the easy-dismantling layer 10, the pressure-sensitive adhesive layer 21 is bonded to the other surface of the easy-disassembling layer 10 to obtain a double-sided pressure-sensitive adhesive tape according to the present invention.

  The production of the double-sided pressure-sensitive adhesive tape is preferably performed at a temperature of 80 ° C. or lower, preferably 40 ° C. to 80 ° C., 50 ° C. to 80 ° C., in order to suppress the expansion of the thermally expandable microspheres. More preferably, it is carried out in the range of ° C.

  In the manufacturing method of the double-sided pressure-sensitive adhesive tape of the present embodiment, since the two pressure-sensitive adhesive layers 20 and 21 of the double-sided pressure-sensitive adhesive tape to be manufactured have the same configuration, the easy-disassembly layer and the pressure-sensitive adhesive layer are individually molded and bonded together. Thus, the step of forming the pressure-sensitive adhesive layer may be performed once, and a double-sided pressure-sensitive adhesive tape can be produced efficiently.

≪Adhesion method / Separation method≫
In the bonding method of the present invention, adherends are bonded to each other with the double-sided pressure-sensitive adhesive tape of the present invention.

  In the separation method of the present invention, the easy-disintegration layer is heated to separate the adherends bonded together by the bonding method of the present invention.

  FIG. 4 is an example of an embodiment of the bonding method of the present invention. As shown in FIG. 4, the adherends 50 and 51 are brought into contact with the pressure-sensitive adhesive layers 20 and 21 on both sides of the double-sided pressure-sensitive adhesive tape, and the adherends are bonded and bonded together.

  FIG. 5 is an example of an embodiment of the separation method according to the present invention.

  First, the double-sided adhesive tape is heated. You may heat a double-sided adhesive tape by heating the said adherend and the whole double-sided adhesive tape which were bonded together. Then, the binder 11 of the easily dismantled layer 10 is softened by heat, and the thermally expandable microspheres 12 expand. At this time, a peeling stress is applied to the double-sided pressure-sensitive adhesive tape by applying force to the double-sided pressure-sensitive adhesive tape in a direction in which the adherends 50 and 51 are separated. Since the easily expandable layer of the double-sided pressure-sensitive adhesive tape of the present invention contains thermally expandable microspheres, the adherends can be easily separated from each other when it expands due to heating or the like.

  FIG. 6 is a diagram schematically showing an example of the state of separation of adherends in the separation method of the present invention and another method. FIG. 6A is an example of the separation method of the present invention, and shows a case where the heat-expandable microspheres 12 are contained in the easy-disassembly layer 10 of the double-sided pressure-sensitive adhesive tape. FIG. 6B shows a case where the heat-expandable microspheres 12 are not contained in the easy-disassembly layer 10 of the double-sided pressure-sensitive adhesive tape.

  As shown in FIG. 6B, when the thermally expandable microspheres 12 are not blended in the easily dismantleable layer 10, the stress applied to the binder 11 is dispersed, and the layer of the binder 11 is difficult to disassemble.

  On the other hand, in the separation method of the present invention, since the heat-expandable microspheres 12 are contained in the easy-disassembly layer 10 of the double-sided pressure-sensitive adhesive tape, as shown in FIG. Compared with the case where the stress applied to the binder 11 is concentrated and the thermally expandable microspheres 12 are not blended in the easily dismantled layer, the easily dismantled layer can be disassembled with less force, and as a result, two or more easily. The adherend can be separated.

  Although the heating performed by the separation method can be appropriately selected depending on the thermally expandable microspheres used and the working environment, it is preferably 85 ° C to 150 ° C, more preferably 90 ° C to 120 ° C. The double-sided pressure-sensitive adhesive tape of the present invention can firmly adhere to adherends without being disassembled in a normal use environment (approximately 80 ° C. or lower), while being heated to the above temperature. The easily dismantled layer can be easily disassembled, and as a result, the adherend can be easily separated.

  Examples of the heating method include a method of directly or indirectly heating the double-sided pressure-sensitive adhesive tape using a dryer or a halogen lamp.

  During the heating, a halogen lamp may be brought close to or in contact with the double-sided pressure-sensitive adhesive tape, or the pressure-sensitive adhesive tape may be indirectly heated by bringing a halogen lamp close to or in contact with the adherend. For example, when the end of the double-sided pressure-sensitive adhesive tape protrudes outside the end of the adherend, a halogen lamp may approach or contact the end of the double-sided pressure-sensitive adhesive tape.

  In the heating step, it is preferable to use a heating device equipped with a halogen lamp or the like and heat the double-sided pressure-sensitive adhesive tape until the temperature reaches 80 ° C. to 130 ° C., more preferably 85 ° C. to 125 ° C. Preferably, heating is performed until the temperature reaches 90 ° C to 120 ° C. The heating is preferably within 20 seconds, more preferably within 15 seconds, and further preferably within a relatively short period of time within 10 seconds.

  Specifically, the heating step using the halogen lamp or the dryer is a step of setting the temperature of the double-sided pressure-sensitive adhesive tape to 100 ° C. within 20 seconds, so that the disassembly efficiency of the article can be improved and This is preferable because deformation of the body due to heat can be prevented.

  In addition, as a heating device equipped with a halogen lamp, for example, a “parallel light type halogen lamp heater” capable of heating a certain area in a short time, a condensing halogen type lamp capable of local heating, or the like may be used. In addition, the use of a parallel light type halogen lamp heater can heat a wide range at a time, so that the heating time can be shortened to the time described above.

Area heatable in the parallel light type halogen lamp heater ^once, preferably a 10cm ² ~500cm 2 about. Moreover, it is preferable that the heating device such as a parallel light type halogen lamp heater has a portable size and weight in order to improve the efficiency of the work for disassembling the article. The weight is preferably 3 kg or less, preferably 2 kg or less, and more preferably 0.1 kg to 1 kg.

  The article heated by the above method can be easily disassembled by applying little or no force to two or more adherends constituting the article.

  Since the double-sided pressure-sensitive adhesive tape of the present invention has a very excellent adhesive force in a temperature range of 60 ° C. or lower, a transparent top plate constituting an electronic device such as a copying machine or a multifunction machine having a copy function or a scan function, for example. And can be used for fixing to the casing.

  As the transparent top plate, it is possible to use a transparent top plate installed in a copying machine or a multifunction peripheral equipped with a general copy function or scan function.

  As the transparent top plate, for example, a transparent plate-like rigid body made of glass or plastic can be used. As said plastic, an acrylic board, a polycarbonate board, etc. can be used, for example.

  As the transparent top plate, those suitable for the shape of the copying machine or the like on which it is installed can be used, but it is usually preferable to use a square or rectangular one.

  If the double-sided pressure-sensitive adhesive tape is, for example, a rectangular transparent top plate, it is preferable that the double-sided pressure-sensitive adhesive tape is affixed along two opposing end portions. At this time, the adhesive tape can be cut into a cover corresponding to the length of the side of the transparent top plate. For example, the width is 0.5 mm to 20 mm and the length is 0.1 mm to 2 mm. It is preferable to use one that is 0 mm.

  Moreover, the double-sided pressure-sensitive adhesive tape of the present invention can be used exclusively for fixing members constituting mobile electronic devices. Examples of the member include two or more casings or lens members constituting an electronic device.

  Examples of the portable electronic device include those having a structure in which a case and one of a lens member or other case are joined via the double-sided adhesive tape as the member.

  Examples of the fixing of the member include a method in which one of the casing or the lens member and the other casing or the lens member are laminated via the double-sided adhesive tape and then cured for a certain period.

  FIG. 7 is an example of an embodiment of the separation method according to the present invention. First, the separation method as shown in FIG. 6 is performed. At this time, the residue of the double-sided adhesive tape that has been disassembled remains on the adherends 50 and 51. Next, the double-sided adhesive tape is cooled. Thereafter, by pulling the base film 41 portion, the entire residue of the double-sided pressure-sensitive adhesive tape can be peeled off from the adherend while the base film and the other layers of the double-sided pressure-sensitive adhesive tape are integrated.

  Cooling may be suitably cooled to a temperature at which the degree of softening of the binder in the residue of the double-sided pressure-sensitive adhesive tape softened by heating is reduced, and the residue of the double-sided pressure-sensitive adhesive tape is removed and becomes easy to handle, and is 35 ° C. or lower. The temperature is preferably 25 ° C. or lower.

[Production Example 1] Easy dismantling layer (1)
Styrene-isoprene block copolymer S having a weight average molecular weight of 200,000 (mixture of triblock copolymer and diblock copolymer. The proportion of the diblock copolymer to the total amount of the mixture is 52% by mass. The mass proportion of polystyrene units in the whole styrene-isoprene block copolymer is 15 mass%, the mass proportion of polyisoprene units is 85 mass%), 100 mass parts, C5 petroleum-based tackifying resin (softening point 100 ° C, number 40 parts by mass of average molecular weight 885), 30 parts by mass of polymerized rosin ester-based tackifier resin (softening point 125 ° C., number average molecular weight 880), HV-100 (manufactured by JX Nippon Mining & Metals Corporation, low 5 parts by mass of molecular weight polybutene), Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) as thermally expandable microspheres A thermal expansion coefficient at 120 ° C. of 370%, an expansion start temperature of 90 ° C. to 100 ° C., a maximum expansion temperature of 125 ° C. to 135 ° C., and a particle diameter (before expansion) of 9 μm to 15 μm) are mixed at a mixing ratio of 10 parts by mass. A synthetic rubber solution was obtained by dissolving in toluene.

  The easy-disintegration layer (1) was manufactured by apply | coating the said solution to the surface of a peeling sheet so that the thickness after drying might be 40 micrometers using an applicator, and making it dry at 85 degreeC for 5 minutes.

[Production Example 2] Easy dismantling layer (2)
Instead of Matsumoto Microsphere F-48, Microsphere Expander 053-40 (manufactured by Nippon Philite Co., Ltd., thermal expansion coefficient at 120 ° C is 350%, expansion start temperature is 96 ° C to 103 ° C, and maximum expansion temperature is 138 ° C. An easily dismantled layer (2) was produced in the same manner as in Production Example 1 except that 10 parts by mass of ˜146 ° C. and particle size (before expansion) of 10 μm to 16 μm) was used.

[Production Example 3] Easy dismantling layer (3)
Instead of Matsumoto Microsphere F-48, Microsphere Expandel 031-40 (manufactured by Nippon Philite Co., Ltd., thermal expansion coefficient at 120 ° C. is 450%, expansion start temperature 81 ° C. to 95 ° C., maximum expansion temperature 120 ° C. An easily dismantled layer (3) was produced in the same manner as in Production Example 1 except that 10 parts by mass of ~ 135 ° C and particle size (before expansion) of 10 µm to 16 µm) was used.

[Production Example 4] Easy dismantling layer (4)
Matsumoto Microsphere FN-80GSD instead of Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., thermal expansion coefficient at 120 ° C is 220%, expansion start temperature 100 ° C to 110 ° C, maximum expansion temperature 125 ° C to An easily dismantled layer (4) was produced in the same manner as in Production Example 1 except that 10 parts by mass of 135 ° C. and a particle size (before expansion) of 6 μm to 10 μm) were used.

[Production Example 5] Easy disassembly layer (5)
Instead of the styrene-isoprene block copolymer S, a styrene-isoprene block copolymer T having a weight average molecular weight of 300,000 (a mixture of a triblock copolymer and a diblock copolymer. The diblock relative to the total amount of the mixture) The proportion of the copolymer is 20% by mass, the mass proportion of the polystyrene unit in the total of the styrene-isoprene block copolymer is 15% by mass, and the mass proportion of the polyisoprene unit is 85% by mass). The easily dismantled layer (5) was produced in the same manner as in Production Example 1.

[Production Example 6] Easy dismantling layer (6)
An easy-disassembly layer (6) was produced in the same manner as in Production Example 1 except that the amount of Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was changed from 10 parts by mass to 20 parts by mass. .

[Production Example 7] Easy dismantling layer (7)
An easy-disassembly layer (7) was produced in the same manner as in Production Example 1 except that the amount of Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was changed from 10 parts by mass to 5 parts by mass. .

[Production Example 8] Easy dismantling layer (8)
An easy disassembly layer (8) was produced in the same manner as in Production Example 1 except that the thickness of the easy disassembly layer was changed from 40 μm to 20 μm.

[Production Example 9] Easy dismantling layer (9)
100 parts by mass of LA2250 (manufactured by Kuraray Co., Ltd., acrylic thermoplastic elastomer), Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., thermal expansion coefficient at 120 ° C. is 370%, and expansion start temperature is 90 ° C. to 100 ° C. An acrylic resin composition having a nonvolatile content of 40% by mass was obtained by mixing 10 parts by mass of toluene, and a maximum expansion temperature of 125 ° C. to 135 ° C. and a particle size (before expansion) of 9 μm to 15 μm).

  Using the applicator, the acrylic resin composition was applied to the surface of the release sheet so that the thickness after drying was 40 μm, and dried at 85 ° C. for 5 minutes to produce an easily dismantled layer (9).

[Production Example 10] Easy dismantling layer (10)
In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 44.9 parts by mass of butyl acrylate, 50 parts by mass of 2-ethylhexyl acrylate, 2 parts by mass of acrylic acid, 3 parts by mass of vinyl acetate , 0.1 part by mass of 4-hydroxybutyl acrylate and 0.1 part by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator are dissolved in 100 parts by mass of ethyl acetate and polymerized at 70 ° C. for 10 hours. As a result, an acrylic copolymer solution having a weight average molecular weight of 800,000 was obtained. Next, 30 parts by mass of a polymerized rosin ester tackifier resin (softening point 125 ° C., number average molecular weight 880) is added to 100 parts by mass of the acrylic copolymer, and ethyl acetate is added and mixed. An acrylic copolymer composition (1) having a nonvolatile content of 45% by mass was obtained.

  100 parts by mass of the acrylic copolymer composition (1), 1.1 parts by mass of “Coronate L-45” (manufactured by Nippon Polyurethane Industry Co., Ltd., isocyanate-based crosslinking agent, solid content 45% by mass), Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., thermal expansion coefficient at 120 ° C. is 370%, expansion start temperature 90 ° C. to 100 ° C., maximum expansion temperature 125 ° C. to 135 ° C., particle diameter (before expansion) 9 μm ~ 15 μm) 10 parts by mass of the mixture is applied to the surface of the release sheet using an applicator so that the thickness after drying is 40 μm, and dried at 85 ° C. for 5 minutes. 10) was formed.

[Production Example 11] Easy disassembly layer (11)
Instead of 44.9 parts by weight of butyl acrylate, 50 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of acrylic acid, 3 parts by weight of vinyl acetate and 0.1 part by weight of 4-hydroxybutyl acrylate, 20 parts by weight of butyl acrylate and 2 parts by weight -The easily disassembled layer (11) was formed by the same method as in Production Example 10 except that 74.9 parts by mass of ethylhexyl acrylate was used.

[Comparative Production Example 1] Core layer (1)
A core layer (1) was produced in the same manner as in Production Example 1 except that Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was not used.

[Comparative Production Example 2] Core layer (2)
A core layer (2) was produced in the same manner as in Production Example 9, except that Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was not used.

[Comparative Production Example 3] Middle core layer (3)
A core layer (3) was produced in the same manner as in Production Example 10 except that Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was not used.

[Comparative Production Example 4] Middle core layer (4)
A core layer (4) was produced in the same manner as in Production Example 11 except that Matsumoto Microsphere F-48 (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was not used.

[Preparation Example 1] Adhesive layer (1)
In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 44.9 parts by mass of butyl acrylate, 50 parts by mass of 2-ethylhexyl acrylate, 2 parts by mass of acrylic acid, 3 parts by mass of vinyl acetate , 0.1 part by mass of 4-hydroxybutyl acrylate and 0.1 part by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator are dissolved in 100 parts by mass of ethyl acetate and polymerized at 70 ° C. for 10 hours. As a result, an acrylic copolymer solution having a weight average molecular weight of 800,000 was obtained. Next, 30 parts by mass of a polymerized rosin ester tackifier resin (softening point 125 ° C., number average molecular weight 880) is added to 100 parts by mass of the acrylic copolymer, and ethyl acetate is added and mixed. An acrylic copolymer composition (1) having a nonvolatile content of 45% by mass was obtained.

  100 parts by mass of the acrylic copolymer composition (1) and 1.1 parts by mass of “Coronate L-45” (manufactured by Nippon Polyurethane Industry Co., Ltd., isocyanate crosslinking agent, solid content 45% by mass) are mixed. The pressure-sensitive adhesive thus obtained was applied to the surface of the release sheet using an applicator so that the thickness after drying was 50 μm, and dried at 85 ° C. for 5 minutes to form a pressure-sensitive adhesive layer (1). .

Example 1
As shown in FIG. 8A, the pressure-sensitive adhesive layer (1) 22 was bonded to a polyethylene terephthalate film 42 having a thickness of 16 μm (bonded product).

On the other hand, another pressure-sensitive adhesive layer (1) 23 and an easily dismantled layer (1) 15 were bonded to both sides of a polyethylene terephthalate film 43 having a thickness of 16 μm. Next, after removing the release sheet on the surface of the easily dismantled layer (1) 15 and bonding it to the bonded product of the polyethylene terephthalate film 42 and the pressure-sensitive adhesive layer (1) 22 prepared previously, 4 kgf / The double-sided pressure-sensitive adhesive tape of Example 1 was produced by pressing and laminating at cm ² .

(Example 2)
A double-sided pressure-sensitive adhesive tape of Example 2 was produced in the same manner as in Example 1 except that the easy-disintegration layer (2) was used instead of the easy-disassembly layer (1).

(Example 3)
A double-sided pressure-sensitive adhesive tape of Example 3 was produced in the same manner as in Example 1 except that the easy-disintegration layer (3) was used instead of the easy-disassembly layer (1).

Example 4
A double-sided pressure-sensitive adhesive tape of Example 4 was produced in the same manner as in Example 1 except that the easy-disassembly layer (4) was used instead of the easy-disassembly layer (1).

(Example 5)
A double-sided pressure-sensitive adhesive tape of Example 5 was produced in the same manner as in Example 1 except that the easy-disassembly layer (5) was used instead of the easy-disassembly layer (1).

(Example 6)
Implemented except that instead of the 16 μm polyethylene terephthalate film on one side, a laminate of a 16 μm thick polyethylene terephthalate film and a 100 μm thick polyolefin foam was used so that the foam side was in contact with the easily disintegrable layer. In the same manner as in Example 1, the double-sided pressure-sensitive adhesive tape of Example 6 was produced.

(Example 7)
A double-sided pressure-sensitive adhesive tape of Example 7 was produced in the same manner as in Example 1 except that the easy-disassembly layer (6) was used instead of the easy-disassembly layer (1).

(Example 8)
A double-sided pressure-sensitive adhesive tape of Example 8 was produced in the same manner as in Example 1 except that the easy-disintegration layer (7) was used instead of the easy-disassembly layer (1).

Example 9
A double-sided pressure-sensitive adhesive tape of Example 9 was produced in the same manner as in Example 1 except that the easy-disassembly layer (8) was used instead of the easy-disassembly layer (1).

(Example 10)
A double-sided pressure-sensitive adhesive tape of Example 10 was produced in the same manner as in Example 1 except that the easy-disassembly layer (9) was used instead of the easy-disassembly layer (1).

(Example 11)
A double-sided pressure-sensitive adhesive tape of Example 11 was produced in the same manner as in Example 1 except that the easy-disintegration layer (10) was used instead of the easy-disassembly layer (1).

(Example 12)
A double-sided pressure-sensitive adhesive tape of Example 12 was produced in the same manner as in Example 1 except that the easy-disassembly layer (11) was used instead of the easy-disassembly layer (1).

(Comparative Example 1)
A double-sided pressure-sensitive adhesive tape of Comparative Example 1 was produced in the same manner as in Example 1 except that the core layer (1) was used in place of the easily dismantled layer (1).

(Comparative Example 2)
A double-sided pressure-sensitive adhesive tape of Comparative Example 2 was produced in the same manner as in Example 1 except that the core layer (2) was used in place of the easy-dismantling layer (1).

(Comparative Example 3)
A double-sided pressure-sensitive adhesive tape of Comparative Example 3 was produced in the same manner as in Example 1 except that the core layer (3) was used in place of the easily dismantled layer (1).

(Comparative Example 4)
A double-sided pressure-sensitive adhesive tape of Comparative Example 4 was produced in the same manner as in Example 1 except that the core layer (4) was used in place of the easily dismantled layer (1).

  The following evaluation was performed about the double-sided adhesive tape obtained in the said Example and comparative example. The obtained results are shown in Tables 1 and 2.

<180 degree peeling adhesion at normal temperature>
180 degree peeling adhesion was measured according to JIS Z 0237.

  The release sheet on one side of the double-sided pressure-sensitive adhesive tape was peeled off, and the pressure-sensitive adhesive layer was lined with an aluminum foil having a thickness of 50 μm. The backed adhesive tape was cut to a width of 20 mm, the release sheet on the other side was peeled off, and the adhesive layer was bonded to the smooth surface of the SUS plate that had been degreased to obtain a test piece.

  After leaving the test piece for 30 minutes in a 23 ° C. environment, using the Tensilon tensile tester [manufactured by A & D Co., Ltd., model: RTM-100], the double-sided adhesive tape constituting the test piece was used. The adhesive strength when peeled from the SUS plate at a speed of 300 mm / min in the direction of 180 degrees was measured.

<180 degree peeling adhesion after heating>
180 degree peeling adhesion was measured according to JIS Z 0237.

  The release sheet on one side of the double-sided pressure-sensitive adhesive tape was peeled off, and the pressure-sensitive adhesive layer was lined with an aluminum foil having a thickness of 50 μm. The backed adhesive tape was cut to a width of 20 mm, the release sheet on the other side was peeled off, and the adhesive layer was bonded to the smooth surface of the SUS plate that had been degreased to obtain a test piece.

  After leaving the test piece for 30 minutes under an environment of 120 ° C., using the Tensilon tensile tester [manufactured by A & D Co., Ltd., model: RTM-100], the double-sided adhesive tape constituting the test piece is used. The adhesive strength when peeled from the SUS plate at a speed of 300 mm / min in the direction of 180 degrees was measured.

<Demolition test after heating>
FIG. 9 is a diagram for explaining a method of dismantling test. First, the double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were cut into a square shape having a side (outer shape) length of 20 mm. The cut double-sided adhesive tape 202 was affixed to a degreased smooth surface of an SUS plate 201 having a length of 100 mm, a width of 30 mm, and a thickness of 1 mm.

  Next, the degreased smooth surface of the SUS plate 201 ′ was applied to the surface opposite to the surface where the double-sided adhesive tape 202 and the SUS plate 201 were applied, and one reciprocating pressure was applied with a 5 kg load roller. A test piece was obtained.

  The prepared test piece, which was left in an environment of 120 ° C. for 30 minutes, was taken out at 23 ° C., and the SUS plate when both ends of the SUS plates 201 and 201 ′ were held by hand and peeled off vertically within 15 seconds. The ease of separation was evaluated.

  (Circle): Since the double-sided adhesive tape broke within the easily dismantled layer, the two SUS plates were separated without applying any force. As a result, the specimen could be dismantled without applying any force.

  Δ: Although the two SUS plates were bonded, they could be separated by applying a slight force, and the test piece could be disassembled.

  X: Unless a considerable force was applied with both hands, the two SUS plates could not be separated and the test piece could not be disassembled.

<Measurement of dynamic viscoelasticity (storage modulus) of the binder constituting the easily dismantled layer and the core layer>
The binder used in the production of the easily dismantled layer and the core layer is dissolved in toluene, and applied to the surface of the release liner using an applicator so that the thickness after drying is 100 μm. By drying for several minutes, a plurality of binder layers having a thickness of 100 μm were formed.

  Next, the test piece which consists of a binder layer with a thickness of 2 mm was created by laminating | stacking the binder layer obtained using the same binder.

A parallel plate having a diameter of 7.9 mm was attached to a viscoelasticity tester (ARES 2kSTD) manufactured by TA Instruments Japan. The test piece is sandwiched between the parallel plates with a compression load of 50 g, and the storage elastic modulus (G ₂₃₎ at 23 ° C. under the conditions of a frequency of 1 Hz, a temperature range of −60 to 150 ° C., and a heating rate of 2 ° C./min. ) And storage elastic modulus (G ₁₂₀ ) at 120 ° C. was measured.

1, 2 ... Double-sided adhesive tape 10 ... Easy disassembly layer 11 ... Binder 12 ... Thermally expandable microsphere (before expansion)
12 '... Thermally expandable microsphere (after expansion)
20, 21 ... Adhesive layer (1)
30, 31, 32, 33, 34 ... release sheet 40, 41 ... base film 50, 51 ... adherend 3, 4 ... double-sided adhesive tape 14 ... thermally expandable microsphere (before expansion)
15 ... Easy dismantling layer (1)
16 ... middle core layer (1)
22, 23 ... Adhesive layer (1)
42, 43 ... Polyethylene terephthalate film

Claims (8)

Two or more adherends are heated in the easy-disassembling layer of an article having a configuration in which a double-sided adhesive tape having an adhesive layer on both sides of the easy-disassembling layer containing a binder and thermally expandable microspheres is heated. A method for separating two or more adherends constituting the article by expanding the thermally expandable microspheres, wherein the storage of the binder is measured by a dynamic viscoelastic spectrum at 1 Hz and 23 ° C. The elastic modulus G ₂₃ is in the range of 1.0 × 10 ^{3 to} 5.0 × 10 ⁷ Pa, and the storage elastic modulus G ₁₂₀ measured by a dynamic viscoelastic spectrum at 1 Hz and 120 ° C. is 1.0 × 10 6. ² to 5.0 × Ri range der of ¹⁰ 6 Pa, a method of separating an adherend thickness of the easily dismantlable layer is characterized 5μm~80μm der Rukoto.   The method for separating an adherend according to claim 1, wherein the binder is a styrene thermoplastic elastomer, an olefin thermoplastic elastomer, an ester thermoplastic elastomer, a silicone resin, or an acrylic resin.   The method for separating an adherend according to claim 1 or 2, wherein the heating method is a method using a halogen lamp or a dryer.   The method for separating an adherend according to claim 3, wherein the halogen lamp is a parallel light type halogen lamp heater.   The method for separating an adherend according to any one of claims 1 to 4, further comprising a base film on at least one of the easily dismantled layer and the pressure-sensitive adhesive layer. The method for separating an adherend according to any one of claims 1 to 5 , wherein a coefficient of thermal expansion of the thermally expandable microsphere is 150% or more at 120 ° C. The method for separating an adherend according to any one of claims 1 to 6 , wherein the heating is heating the easily dismantled layer to 85 ° C to 150 ° C. The separation method according to any one of claims 1 to 7 , wherein the two or more adherends are rigid bodies.

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