CN111601860B

CN111601860B - Adhesive tape, article, and method for producing article

Info

Publication number: CN111601860B
Application number: CN201980008234.1A
Authority: CN
Inventors: 唐泽久美子; 谷井翔太; 秋山诚二; 下冈澄生; 森野彰规
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2018-02-09
Filing date: 2019-01-24
Publication date: 2022-12-20
Anticipated expiration: 2039-01-24
Also published as: JP6874867B2; JPWO2019155896A1; CN111601860A; WO2019155896A1

Abstract

The invention provides an adhesive tape which has adhesiveness at normal temperature, can show excellent adhesive force even after being heated and expanded, and does not cost manufacturing cost. The present invention relates to an adhesive tape having an expandable thermosetting adhesive layer (A) which expands by external stimulus on at least one surface thereof, wherein the expandable thermosetting adhesive layer (A) has a 180-degree peel adhesion at 23 ℃ of 0.1N/20mm or more.

Description

Adhesive tape, article, and method for manufacturing article

Technical Field

The present invention relates to an adhesive tape having adhesiveness at normal temperature and having a structure expandable in the thickness direction thereof.

Background

Generally, an adhesive tape is suitably used for fixing one adherend to a flat portion, a curved portion, or the like of another adherend, and is widely used in manufacturing places of various products such as automobile members and electric devices.

On the other hand, in a process in which an increasingly wider range of use of the adhesive tape is expected, the adhesive tape is required to be suitably used in a case where, for example, one adherend has a void in which another adherend is fixed. Specifically, as an engine mounted on a hybrid vehicle or the like, an engine having a structure in which a magnet is embedded in a specific position (gap) of a core portion (rotor core) is generally known, and the use of the adhesive tape for fixing the magnet in the gap of the core portion has been studied.

As an adhesive tape that can be used for the above-described applications, a thermosetting heat-expandable adhesive tape that expands when heated and fills and fixes a gap between members is known (see, for example, patent document 1).

However, since the thermosetting adhesive tape does not have sufficient adhesive strength in a state before heating, it is difficult to temporarily attach (temporarily adhere) the thermosetting adhesive tape to a specific position of an adherend before heating, and in order to perform temporary attachment, the thermosetting adhesive tape needs to be pressed against the adherend at a high temperature, which may increase the number of processing steps.

On the other hand, patent document 2 proposes an adhesive tape comprising at least 3 layers, in which an adhesive layer is provided on one surface of a heat-sealing layer and a heat-sealing layer having no adhesiveness is provided on the other surface, in order to impart initial adhesiveness. However, in this case, there is a problem that the production cost is more expensive than that of the conventional single-layer thermosetting adhesive tape.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2007-106963

Patent document 2: japanese laid-open patent publication No. 2010-261030

Disclosure of Invention

(problems to be solved by the invention)

The invention provides an adhesive tape which has adhesiveness at normal temperature, can show excellent adhesive force even after being heated and expanded, and does not cost manufacturing cost.

(means for solving the problems)

The present invention provides an adhesive tape, which has an expandable thermosetting adhesive layer (A) that expands due to external stimulus on at least one surface thereof, wherein the expandable thermosetting adhesive layer (A) has a 180-degree peel adhesion at 23 ℃ of 0.1N/20mm or more.

(effect of the invention)

The adhesive tape of the present invention has adhesiveness at normal temperature, and therefore can be bonded to an accurate position of an adherend even before heating, and does not cause displacement of the bonding position of the adhesive tape after temporary bonding, and therefore can sufficiently fill or bond the gaps of the adherend and the gaps between 2 or more adherends. In addition, since an adhesive layer is not required to be additionally provided, the manufacturing cost can be reduced.

Drawings

FIG. 1 is a conceptual diagram illustrating a method of measuring shear adhesion.

Fig. 2 shows an example of the embodiment of the present invention.

Fig. 3 shows an example of the embodiment of the present invention.

Fig. 4 shows an example of the embodiment of the present invention.

Detailed Description

The adhesive tape of the present invention has an expandable thermosetting adhesive layer (A) which expands due to external stimulus on at least one surface thereof, and the expandable thermosetting adhesive layer (A) has a 180-degree peel adhesion at 23 ℃ of 0.1N/20mm or more. The adhesive tape may have a single-layer expandable thermosetting adhesive layer (a), or may have 2 or more layers. When the number of layers is 2 or more, they may be the same or different. The adhesive tape preferably has the expandable thermosetting adhesive layer (a) on both surfaces, and more preferably comprises a single layer of the expandable thermosetting adhesive layer (a).

The adhesive tape may further include a base material and another adhesive layer (B) in addition to the expandable thermosetting adhesive layer.

The expandable thermosetting adhesive layer (a) expands due to external stimulus. As the stimulus from the outside, heat, light, and the like can be given, and among them, heat is preferable.

The expandable thermosetting adhesive layer (a) is one having an expansion ratio [ the thickness of the expandable thermosetting adhesive layer (a') after heating/the thickness of the expandable thermosetting adhesive layer (a) before heating ] in the thickness direction of the expandable thermosetting adhesive layer (a) of 150% or more, and is used. The expansion ratio is preferably 175% or more, and more preferably 200% to 1000%. In the case of the adhesive tape, even when the height (thickness) of the gap of the adherend (C1) or the gap between the adherend (C1) and the adherend (C2) is large, the adhesive tape can be expanded to appropriately fix the other adherend in the gap or fill the gap with the adhesive tape. In the case of the adhesive tape, even when the surface of the adherend is rough, another adherend can be appropriately fixed to the rough surface.

The expansion ratio is a ratio of the thickness of the expanded thermosetting adhesive layer (a') formed by expanding the expandable thermosetting adhesive layer (a) by the standing at a temperature of 50 to 200 ℃ for 10 minutes to the thickness of the expandable thermosetting adhesive layer (a) before the standing (before the expansion).

The thickness of the expandable thermosetting adhesive layer (a) of the adhesive tape is preferably in the range of 10 to 250 μm, more preferably in the range of 15 to 200 μm, and in the range of 20 to 150 μm, and even if an expanding agent described later is added, a smooth adhesive tape can be obtained, and even before heating, a level of adhesiveness capable of temporary adhesion can be imparted to an adherend, and therefore, it is preferable.

On the other hand, the thickness of the expansive thermosetting adhesive layer (a') formed by the expansion of the expansive thermosetting adhesive layer (a) is preferably in the range of 20 μm to 2500 μm, and a range of 40 μm to 1500 μm is preferable in terms of obtaining more excellent adhesive strength. The expanded thermosetting adhesive layer (a') preferably has a porous structure.

The pressure-sensitive adhesive tape is preferably one having a thickness of the expandable thermosetting adhesive layer (a) of 10% or more relative to the total thickness of the pressure-sensitive adhesive tape, and more preferably one having a thickness of the expandable thermosetting adhesive layer (a) of 30% or more because the pressure-sensitive adhesive tape is filled between the adherend (C1), (C2) having a void and is easily and appropriately fixed.

The expandable thermosetting adhesive layer (a) is used as described above, that is, an expandable thermosetting adhesive layer (a) having such an adhesive strength that it can be adhered to an adherend (C1) in advance at room temperature (23 ℃), and a gap of the adherend (C1) or a gap between the adherend (C1) and an adherend (C2) can be filled and adhered by a pressure force generated by expansion of the expandable thermosetting adhesive layer (a).

The adhesive strength of the expandable thermosetting adhesive layer (A) is 0.1N/20mm or more at room temperature (23 ℃ C.) at a 180-degree peel adhesion in accordance with JIS Z0237. Preferably 0.3N/20mm or more, more preferably 0.5N/20mm or more, and still more preferably 0.75N/20mm or more, and a 180-degree peel adhesion of 1N/20mm or more, the adhesive tape adhered to the adherend (C1) can be prevented from being wound up or the adhering position of the adhesive tape is prevented from being shifted due to the obstruction of the adherend (C2) by the adherend (C2) after the adhesive tape is temporarily adhered to the adherend (C1), for example, when the adherend (C1) and the adherend (C2) are assembled, and thus it is more preferable.

As the expandable thermosetting adhesive layer (a), an adhesive composition (a) containing a thermosetting resin or the like described later can be used.

As the thermosetting resin, for example, 1 or 2 or more thermosetting resins selected from urethane resin, phenol resin, unsaturated polyester resin, epoxy resin, acrylic resin, and the like can be used. Among them, as the thermosetting resin, an epoxy resin and/or an acrylic resin is preferably used in view of imparting good adhesion to an adherend during heat curing, and an epoxy resin is more preferably used in view of securing good heat curing properties.

The epoxy resin is preferably used in a range of 80 mass% or more with respect to the total amount of the thermosetting resin, and more preferably in a range of 90 mass% or more in order to appropriately fix an adherend and secure an adhesive layer with little change in adhesive strength during heating.

Specific examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol a type epoxy resins and bisphenol F type epoxy resins, dicyclopentadiene type epoxy resins such as dicyclopentadiene-phenol addition reaction type epoxy resins, biphenyl type epoxy resins, tetramethylbiphenyl type epoxy resins, polyhydroxynaphthalene type epoxy resins, isocyanate modified epoxy resins, 10- (2, 5-dihydroxyphenyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide modified epoxy resins, phenol novolak type epoxy resins, cresol novolak type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, phenol aralkyl type epoxy resins, naphthol novolak type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol cocondensed novolak type epoxy resins, naphthol-cresol cocondensed novolak type epoxy resins, aromatic hydrocarbon formaldehyde resin modified novolak type epoxy resins, biphenyl modified novolak type epoxy resins, and the like.

Among them, as the epoxy resin, it is preferable to use an epoxy resin (a 1) having an epoxy equivalent of 100 to 450g/eq in a liquid state at 25 ℃ and an epoxy resin (a 2) having an epoxy equivalent of 200 to 2000g/eq in a melt viscosity of 0.01 dpas s or more at 150 ℃, and it is more preferable to use a combination of them in terms of both of a level adhesiveness to temporarily adhere to an adherend before heating and a strong adhesiveness after heating. The melt viscosity at 150 ℃ is a value measured by an ICI viscometer in accordance with ASTM D4287.

The viscosity at 25 ℃ of the epoxy resin (a 1) is preferably 1 to 200 mPas, more preferably 10 to 150 mPas, even more preferably 30 to 10 mPas, and most preferably 100 to 5000 mPas, in view of the combination of the adhesion property at a level enabling the temporary adhesion to an adherend before heating and the strong adhesion property after heating.

The epoxy resin (a 1) is preferably used in a range of 1 to 50 mass% with respect to the total amount of the thermosetting resin, and more preferably in a range of 5 to 30 mass% from the viewpoint of appropriately fixing an adherend and ensuring a smooth sheet shape before heating.

Examples of the epoxy resin (a 1) include bisphenol type epoxy resins such as bisphenol a type epoxy resin and bisphenol F type epoxy resin, 1, 6-dihydroxynaphthalene type epoxy resin, t-butylphthalol type epoxy resin, 4' -diphenyldiaminomethane type epoxy resin, p-or m-aminophenol type epoxy resin, trimethylolpropane type epoxy resin, 1, 6-hexanediol type epoxy resin, 1, 4-butanediol type epoxy resin, and aliphatic chain-modified epoxy resin.

The melt viscosity at 150 ℃ of the epoxy resin (a 2) is preferably 0.01 dpas or more, more preferably 0.05 dpas to 50 dpas, and still more preferably 0.1 dpas to 20 dpas, and most preferably 0.2 dpas to 5.0 dpas from the viewpoint of appropriately adjusting the expansibility of the expandable adhesive layer (a).

The softening point of the epoxy resin (a 2) is preferably 10 to 180 ℃, more preferably 15 to 150 ℃, and still more preferably 15 to 100 ℃, and most preferably 20 to 80 ℃ in terms of appropriately adjusting the expansibility of the expandable adhesive layer (a). The softening point is a value measured in accordance with JIS K7234.

The epoxy resin (a 2) is preferably used in a range of 5 to 80 mass% with respect to the total amount of the thermosetting resin, and more preferably in a range of 10 to 50 mass% from the viewpoint of appropriately fixing an adherend and ensuring a smooth sheet shape before heating.

Examples of the epoxy resin (a 2) include dicyclopentadiene type epoxy resins obtained by reacting a bisphenol type epoxy resin with a bisphenol compound, dicyclopentadiene type epoxy resins such as dicyclopentadiene addition reaction type epoxy resins, polyhydroxynaphthalene type epoxy resins, triphenylmethane type epoxy resins, isocyanate-modified bisphenol type epoxy resins, 10- (2, 5-dihydroxyphenyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-modified epoxy resins, copolymers of 2-methoxynaphthalene and o-cresol novolac type epoxy resins, biphenylene type phenol aralkyl resins, and the like, and among them, dicyclopentadiene type epoxy resins such as dicyclopentadiene addition reaction type epoxy resins, isocyanate-modified bisphenol type epoxy resins, 10- (2, 5-dihydroxyphenyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-modified epoxy resins, triphenylmethane type epoxy resins are preferably used from the viewpoint of both adhesiveness and heat resistance.

The epoxy resin (a 3) may be used in combination with the epoxy resin (a 1) and the epoxy resin (a 2), and the epoxy equivalent of the epoxy resin (a 3) is preferably 2000g/eq or more, preferably more than 2000g/eq and 10000g/eq or less.

The epoxy resin (a 3) is preferably used in a range of 40 to 95% by mass, preferably 45 to 94% by mass, preferably 50 to 93% by mass, preferably 55 to 92% by mass, preferably 60 to 91% by mass, and more preferably 65 to 90% by mass, based on the total amount of the thermosetting resin, in order to ensure a smooth sheet shape before heating.

In addition, as the expandable thermosetting adhesive layer (a), a layer containing a curing agent that can react with the thermosetting resin is preferably used.

As the curing agent, for example, if an epoxy resin is used as the thermosetting resin, it is preferable to use a curing agent having a functional group reactive with the epoxy group.

The curing temperature of the thermosetting material is preferably not lower than the expansion temperature of an expanding agent described later, and the curing time is preferably not lower than the expansion time. This makes it possible to sufficiently expand the expanding agent in the thermosetting material softened by heating, and to make the expanded sheet uniform in thickness.

Examples of the curing agent include amine compounds, amide compounds, acid anhydride compounds, and phenol compounds. For example, diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole derivatives, BF 3-amine complexes, guanidine derivatives, and the like can be used as the amine-based compound.

Examples of the amide compound include polyamide resins synthesized from dicyandiamide, a dimer of linolenic acid, and ethylenediamine, examples of the acid anhydride compound include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride, and examples of the phenol compound include phenol novolak resins, cresol novolak resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resins, dicyclopentadiene phenol addition resins, phenol aralkyl resins (XYLOK resins), naphthol aralkyl resins, trimethylolmethane resins, tetraphenol ethane resins, naphthol novolak resins, naphthol-phenol cocondensed novolak resins, naphthol-cresol cocondensed novolak resins, biphenyl-modified phenolic resins (polyhydric phenol compounds in which phenol nuclei are linked by a bismethylene), biphenyl-modified naphthol resins (polyhydric naphthol compounds in which phenol nuclei are linked by a bismethylene), aminotriazine-modified phenolic resins (compounds having a phenol skeleton, a triazine ring, and a primary amino group in a molecular structure), alkoxy group-containing modified phenolic novolak resins (polyhydric phenol compounds in which phenol nuclei are linked by a methylene nucleus and a polyphenol nucleus) and aromatic nucleus, and the like.

The curing agent is preferably used in a range of 1 to 60 parts by mass, more preferably 5 to 30 parts by mass, based on 100 parts by mass of the total of the thermosetting resins such as the epoxy resin.

Further, as the above-mentioned thermosetting material, a thermosetting material containing a curing accelerator can be used. As the curing accelerator, a phosphorus compound, an amine compound, an imidazole derivative, or the like can be used. The amount of the curing accelerator used is preferably in the range of 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, based on 100 parts by mass of the total of the thermosetting resins such as the epoxy resin.

The curing agent and the curing accelerator are preferably used in the form of powder. The above-mentioned powdery curing accelerator can suppress the thermosetting reaction at a low temperature as compared with a liquid curing accelerator, and therefore can further improve the storage stability of the thermosetting material before thermosetting at room temperature.

In addition, as the expandable thermosetting adhesive layer (a), a layer containing a thermoplastic resin can be used in a range that does not impair fixability of the bonded portion even when an expandable thermosetting adhesive layer (a') composed of a thermosetting product thereof is used in an environment where a temperature change is large.

Examples of the thermoplastic resin include polyurethane resins such as Polyurethane (PU) and Thermoplastic Polyurethane (TPU); polycarbonate (PC); vinyl chloride resins such as polyvinyl chloride (PVC) and vinyl chloride-vinyl acetate copolymer resins; acrylic resins such as polyacrylic acid, polymethacrylic acid, polymethyl acrylate, polymethyl methacrylate (PMMA), and polyethyl methacrylate; polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, polypropylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate; polyamide resins such as nylon (registered trademark); polystyrene resins such as Polystyrene (PS), imide-modified polystyrene, acrylonitrile-butadiene-styrene (ABS) resins, imide-modified ABS resins, styrene-acrylonitrile copolymer (SAN) resins, acrylonitrile-ethylene-propylene-diene-styrene (AES) resins, and olefin resins such as Polyethylene (PE) resins, polypropylene (PP) resins, and cycloolefin resins; cellulose resins such as nitrocellulose and cellulose acetate; a silicone resin; thermoplastic resins such as fluorine-based resins, thermoplastic elastomers such as styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, ester-based thermoplastic elastomers, and amide-based thermoplastic elastomers.

For the above reasons, the thermoplastic resin is preferably used in a range of 1 part by mass to 100 parts by mass with respect to 100 parts by mass of the thermosetting resin.

In addition to the above-described materials, examples of the thermosetting material include fillers, softening agents, stabilizers, adhesion promoters, leveling agents, antifoaming agents, plasticizers, tackifying resins, fibers, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, thickeners, colorants such as pigments, and materials containing additives such as fillers, as long as the effects of the present invention are not impaired.

The curing agent and the curing accelerator are preferably used before thermosetting the thermosetting material or before molding the thermosetting material into a sheet.

As the swelling agent that can be contained in the swelling thermosetting adhesive layer (a), it is preferable to use a swelling agent that can form a porous structure in the swelling thermosetting adhesive layer (a ') after swelling, and examples of the swelling agent include inorganic compounds such as ammonium carbonate, ammonium bicarbonate, ammonium nitrite, ammonium borohydride, and azide, fluorinated alkanes such as trichloromonofluoromethane, azo compounds such as azobisisobutyronitrile, hydrazine compounds such as p-toluenesulfonyl hydrazide, semicarbazide compounds such as p-toluenesulfonyl semicarbazide, triazole compounds such as 5-morpholino-1, 2,3, 4-thiatriazole, and N-nitroso compounds such as N, N' -dinitrosoterephthalamide.

As the swelling agent, for example, a swelling capsule obtained by microencapsulating a hydrocarbon-based solvent can be used. The swelling agent may be used alone or in combination of 2 or more.

As the swelling agent, a swelling capsule obtained by microencapsulating a hydrocarbon-based solvent is used, and it is more preferable to prevent deterioration of the swelling thermosetting adhesive layer (a) due to the influence of heat or the like, for example.

The swelling agent is preferably a swelling agent that can swell the adhesive tape at a temperature around the softening point of the expandable thermosetting adhesive layer (a) because the swelling agent can sufficiently swell the adhesive tape.

Examples of commercially available products of the expandable capsule include Expancel (manufactured by Japan Fillite corporation), matsumoto Microsphere (manufactured by masson oil & fat pharmaceuticals), microsphere (manufactured by KUREHA corporation), and the like. As the expandable capsule, it is preferable to use one having a volume after expansion 8 to 60 times the volume of the capsule before expansion (volume expansion ratio).

The amount of the expanding agent to be used, preferably the amount of the thermally expandable capsule to be used, is preferably in the range of 0.3 to 30 parts by mass, more preferably in the range of 0.5 to 25 parts by mass, per 100 parts by mass of the solid content of the entire components of the expandable thermosetting adhesive layer (a), and is more preferably in the range of 1 to 20 parts by mass from the viewpoint of sufficiently expanding to fill in voids and the like in an adherend and obtaining a further excellent adhesive strength.

The pressure-sensitive adhesive tape of the present invention may have a base material and another adhesive layer (B) in addition to the expandable thermosetting adhesive layer (a) as described above. The adhesive layer (B) constituting the adhesive tape may be formed using an adhesive composition (B) which can form a layer having adhesiveness or tackiness.

As the adhesive layer (B), a layer having an expansion ratio in the thickness direction of the adhesive layer (B) ([ thickness of the adhesive layer (B) after the standing after heating/thickness of the adhesive layer (B) before the standing ] × 100 of 120% or less can be used. The expansion rate of the adhesive layer (B) is preferably 115% or less, and more preferably 110% or less. In the case of the pressure-sensitive adhesive tape, even after the expandable thermosetting adhesive layer (a) expands, excellent adhesion to an adherend can be maintained. The expansion rate of the adhesive layer (B) is a ratio of the thickness of the adhesive layer after the adhesive tape is left to stand at 50 to 200 ℃ for 10 minutes to the thickness of the adhesive layer (B) before the adhesive tape is left to stand.

The thickness of the adhesive layer (B) is preferably in the range of 1 μm to 150 μm, and in the range of 5 μm to 100 μm, and the expandable thermosetting adhesive layer (a) constituting the adhesive tape expands to fill the gap of the adherend (C1) or the gap between the adherend (C1) and the adherend (C2), and thus excellent adhesion can be exhibited when the adhesive layer (B) is bonded to the adherend (C2), which is more preferable.

As described above, the adhesive layer (B) preferably has a low expansion ratio, and therefore, it is preferable that the adhesive layer (B) does not substantially contain an expanding agent exemplified as an expanding agent that can be used in forming the expandable thermosetting adhesive layer (a). As the adhesive layer (B), for example, an adhesive composition (B) containing a resin such as a thermosetting resin or a thermoplastic resin and containing a small amount of the swelling agent or not containing the swelling agent can be suitably used.

As the resin usable in the adhesive composition (b), conventionally known resins can be selected and used. Among these, in order to improve the production efficiency of the adhesive tape of the present invention, it is preferable to use, as the resin, for example, the same resin as the resin exemplified as the resin contained in the adhesive composition (a) usable for forming the thermosetting adhesive layer (a).

As the adhesive composition (b), for example, an adhesive composition containing a resin such as the above thermosetting resin or thermoplastic resin, and an additive such as a thickener or a crosslinking agent, which is used as needed, can be used.

As the above-mentioned tackifier resin, for the purpose of adjusting the strong adhesiveness of the adhesive layer (B), for example, a rosin-based tackifier resin, a polymerized rosin ester-based tackifier resin, a rosin phenol-based tackifier resin, a stabilized rosin ester-based tackifier resin, a disproportionated rosin ester-based tackifier resin, a terpene phenol-based tackifier resin, a petroleum resin-based tackifier resin, and the like can be used.

As the crosslinking agent, for the purpose of increasing the cohesive force of the adhesive layer (B), known isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, polyvalent metal salt-based crosslinking agents, metal chelate-based crosslinking agents, ketone/hydrazide-based crosslinking agents, oxazoline-based crosslinking agents, carbodiimide-based crosslinking agents, silane-based crosslinking agents, glycidyl (alkoxy) epoxy silane-based crosslinking agents, and the like can be used.

As the above-mentioned additives, known additives such as alkali (ammonia water and the like), acid, adhesion promoter, stabilizer, foaming agent, plasticizer, softener, antioxidant, fibrous, balloon, bead, or metallic powder filler made of glass or plastic, colorant such as pigment, dye, ultraviolet absorber, hydrolysis inhibitor, pH adjuster, coating film forming aid, leveling agent, thickener, water repellent, and defoaming agent for adjusting pH can be used as necessary within a range not to impair the desired effects of the present invention.

As the adhesive composition (b), an adhesive composition containing a solvent can be used from the viewpoint of maintaining good coating workability. Examples of the solvent include toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, and hexane. In the case where an aqueous adhesive composition is used as the adhesive composition (b), water or an aqueous solvent mainly containing water can be used as the solvent.

The adhesive tape of the present invention can be produced, for example, through a step [ I ], in which the adhesive composition (a) is applied to a release liner and dried to form an expandable thermosetting adhesive layer (a).

In the pressure-sensitive adhesive tape of the present invention, the pressure-sensitive adhesive tape comprising the expandable thermosetting adhesive layer (a) and the adhesive layer (B) can be produced by the step [ I ], the step [ II ] and the step [ III ] other than the step [ I ], wherein the step [ II ] forms the adhesive layer (B) by applying the adhesive composition (B) to a release liner and drying it, and the step [ III ] transfers the adhesive layer (B) to one surface of the expandable thermosetting adhesive layer (a) and pressure-bonds them.

The expandable thermosetting adhesive layer (a) is preferably not substantially expanded in the process of producing the adhesive tape.

As the pressure-sensitive adhesive tape of the present invention, a pressure-sensitive adhesive tape having a nonwoven fabric layer, a resin film layer or a metal layer (Z) between the expandable thermosetting pressure-sensitive adhesive layer (a) and the pressure-sensitive adhesive layer (B) can be used as needed. The adhesive tape has good rigidity and thus has excellent adhesion workability.

The layer (Z) is preferably made of pulp, rayon, abaca, acrylonitrile, nylon, polyester, or the like if it is a nonwoven fabric, and may be subjected to a 1-step impregnation treatment in which polyamide is added to the paper-making step, dried, and then coated, as necessary, in order to satisfy the tensile strength of the nonwoven fabric; and 2-step impregnation treatment using viscose or thermoplastic resin as a binder. Examples of the resin film include resin film layers formed using plastic films such as polyester films, polyethylene films, polypropylene films, polyvinyl chloride films, and polyimide films, and examples of the layer made of metal include metal layers such as aluminum and copper.

As the layer (Z), a layer having a thickness of 1 μm to 200 μm is preferably used.

The adhesive tape having the layer (Z) can be produced, for example, by the step [ I ] of applying the adhesive composition (a) to a release liner and drying the same to form an expandable thermosetting adhesive layer (a), the step [ II ] of applying the adhesive composition (B) to a release liner and drying the same to form an adhesive layer (B), the step [ IV ] of laminating the layer (Z) on one surface of the expandable thermosetting adhesive layer (a), and the step [ V ] of transferring the adhesive layer (B) to the surface constituted by the layer (Z) and pressure-bonding the same.

In the present invention, by using an adhesive tape which has initial adhesiveness, swells when stimulated, and has excellent adhesive strength even after swelling, an article having a void in the adherend (C1) or a void between the adherend (C1) and the adherend (C2), for example, can be suitably used in the manufacturing site of an article in which the void is filled or bonded with the adhesive tape.

Examples of the method for producing the article include a method for producing an article in which the article is bonded or filled in a gap of an adherend (C1) or a gap between the adherend (C1) and an adherend (C2) via an expanded product of a pressure-sensitive adhesive tape, the method comprising the steps of: a step [1] of applying an expandable thermosetting adhesive layer (A) constituting a pressure-sensitive adhesive tape to a site (C1-1) constituting an adherend (C1); a step [2] of applying a stimulus to the expandable thermosetting adhesive layer (A); a step [3] in which the expansive thermosetting adhesive layer (A) expands due to the stimulus to form an expansive thermosetting adhesive layer (A'); and a step [4] of adhering the expanded thermosetting adhesive layer (A') or the adhesive layer (B) constituting the adhesive tape to the other part (C1-2) constituting the adherend (C1) or the other adherend (C2).

In the above step [1]In (2), the thermosetting adhesive layer (A) of the adhesive tape is set at 0.1N/cm ² The above-mentioned pressure contact with the site (C1-1) constituting the adherend (C1) is preferable because the adhesion of the adhesive tape to the site (C1-1) constituting the adherend (C1) is improved and the displacement of the adhesive tape from the adherend (C1) can be suppressed even before heating. The adhesive tape of the present invention has adhesiveness at normal temperature, but when higher adhesiveness is required, the adhesive tape may be heated to adhere to the adherend (C1). In this case, the temperature of the heat-sensitive adhesive tape is preferably from room temperature (23 ℃) to 100 ℃, and is more preferably 80 ℃ or lower because the expandable thermosetting adhesive layer (a) can be pressure-bonded to the adherend without expanding or deforming the shape of the adhesive tape.

When the expandable thermosetting thermally expandable adhesive layer (a) or the adhesive layer (B) of the adhesive tape is pressure-bonded to the site (C1-1) constituting the adherend (C1), equipment such as a press machine or a roller may be used as needed, or they may be pressed with fingers.

In the step of applying a stimulus to the expandable thermosetting adhesive layer (a) in the step [2], the stimulus is preferably heat. Among them, the heating temperature is preferably a temperature corresponding to the temperature at which the swelling agent swells (swelling start temperature), specifically, preferably 50 to 200 ℃, more preferably 60 to 190 ℃, and is preferably 70 to 180 ℃ because the adhesive tape has excellent storage stability, sufficiently swells and can obtain excellent adhesion after swelling.

Examples of the heating method include a method in which an article is put into a heating apparatus such as an oven or a heating furnace to heat the entire article; and a method of heating the expandable thermosetting adhesive layer (a) by bringing a heat source into contact with or close to the expandable thermosetting adhesive layer (a) or the adhesive tape or the adherend. Examples of the heat source include a halogen lamp, a laser irradiation device, an electromagnetic induction heating device, a hot stamp, a hot plate, and a soldering iron. The heating method may be selected according to the size of the article.

In the step [4], the expansive thermosetting adhesive layer (a') or the adhesive layer (B) is brought into pressure contact with another part (C1-2) constituting the adherend (C1) or another adherend (C2) by a force generated by expanding the expansive thermosetting adhesive layer (a). Therefore, when filling the gap of the adherend (C1) or the gap between the adherend (C1) and the adherend (C2), it is not necessary to apply pressure using, for example, a press machine. Further, since the pressure-sensitive adhesive tape is brought into close contact with the adherend by the force generated by the expansion, even when the adherend having irregularities on the surface (adherend having a rough surface) is used as the adherend, a gap is not easily formed between the pressure-sensitive adhesive tape and the adherend. Examples of the adherend (C1) and (C2) include glass, metal such as aluminum, stainless steel, and copper, and plastic made of resin such as acrylic, polycarbonate, and polyimide. The adherends (C1) and (C2) may be made of the same material and shape, or may be made of different materials and shapes. The surfaces of the expandable thermosetting adhesive layer (a) and the adhesive layer (B) that contact each other may be roughened surfaces as the adherends (C1) and (C2).

The shape of the surface of the adherend (C1) or the adherend (C2) where the expandable thermosetting adhesive layer (a) or the adhesive layer (B) is in contact may include, for example, a surface having minute irregularities of 1 μm or less, irregularities of 1 μm or more such as embossing or printing step differences (printing step differences), warpage or deformation of the adherend itself. The irregularities are preferably 500 μm or less, more preferably 400 μm or less, and further preferably 300 μm or less, and the difference between the highest point and the lowest point of the height with respect to the plane is preferably 500 μm or less, more preferably 400 μm or less, as the warpage or deformation of the adherend itself, and at 300 μm or less, good adhesiveness is obtained by utilizing the pressure generated when the expandable thermosetting adhesive layer (a) is expanded in the steps [2] to [4 ]. The adherend may be a combination of curved surfaces, and the curved surfaces may be curved surfaces having the same radius of curvature or curved surfaces having different radii of curvature. When the radius of curvature is in the range of 0.1mm to 10m, good adhesiveness can be obtained by utilizing the pressure generated when the expandable thermosetting adhesive layer (a) is expanded in the steps [2] to [4 ]. When the radii of curvature of the adherends are different from each other, the gap formed between the adherends is preferably 500 μm or less, more preferably 400 μm or less, and 300 μm or less, and in the steps [2] to [4], the pressure generated when the expandable thermosetting adhesive layer (a) is expanded can be used to obtain good adhesiveness.

The shapes of the adherend (C1) and the adherend (C2) are not particularly limited, and examples thereof include a two-dimensional shape, a three-dimensional shape (curved surface, etc.), a shape having surface irregularities, and a fitting shape. Combinations of the above shapes are also possible.

The method of producing the article is preferably a method in which the steps [1], [2] and [3] are performed in this order, and the article has excellent adhesion before heating, can be expanded by heating, and exhibits excellent adhesion even after expansion by heating. In particular, when the surface of the adherend (C1) or (C2) is a rough surface, it is effective in exhibiting good adhesion.

Examples of the article obtained by the above method include a small engine mounted on a movable portion of an automobile. The engine is generally composed of an exterior member (cylindrical member) and a cover member thereof. Specifically, the engine is fixed in a state in which a metal cylindrical member and a resin cover-like member having a shape corresponding to the cylindrical member are fitted to each other. The adhesive tape of the present invention can fill a gap formed between the cylindrical member and the lid member.

In addition, the adhesive tape of the present invention can be used for fixing display panels and housings of mobile phones, smart phones, tablet computers, televisions, car navigation systems, and the like.

The adhesive tape of the present invention is useful for fixing a thin film material to an adherend having irregularities while maintaining a smooth state. As a specific example, the substrate and the reflective sheet are fixed in the direct type LED light emitting device. When the substrate surface of the light-emitting device is coated with a resist ink and the reflective sheet is fixed with a tape so as to follow the unevenness of the ink layer, the reflective sheet undulates and does not exhibit optical characteristics. The use of the adhesive tape of the present invention is preferable because the reflective sheet can be smoothly fixed while the adhesive tape follows the irregularities of the resist ink layer.

[ examples ] A method for producing a compound

The following specifically describes examples and comparative examples.

Preparation example 1

A thermosetting resin composition (X-1) was prepared by mixing 7.0 parts by mass of an epoxy resin 1 (epoxy equivalent 403g/eq., liquid (25 ℃ C.), viscosity 140 ten thousand mPas (25 ℃ C.), 28 parts by mass of an epoxy resin 2 (epoxy equivalent 162g/eq., solid (25 ℃ C.), melt viscosity 0.2dPa s at 150 ℃ C., softening point 25 ℃ C.), 216.7 parts by mass of a methyl ethyl ketone solution (solid content 30 mass%) of an epoxy resin 3 (epoxy equivalent 8000g/eq., solid (25 ℃ C.), softening point 200 ℃ C.) or higher) and 2.0 parts by mass of a curing agent (2, 4-diamino-6- [2 '-methylimidazolyl- (1') ] -ethyl-s-triazine isocyanuric acid adduct).

(preparation example 2)

A thermosetting adhesive composition (X-2) was obtained in the same manner as in preparation example 1, except that 7 parts by mass of the epoxy resin 1 was changed to 2 parts by mass, and 5 parts by mass of the epoxy resin 4 (epoxy equivalent 130g/eq., liquid state (25 ℃ C.), viscosity 300mPa · s (25 ℃ C.)) was used.

Preparation example 3

A thermosetting adhesive composition (X-3) was obtained in the same manner as in preparation example 1, except that the amount of the methyl ethyl ketone solution (solid content: 30 mass%) of epoxy resin 3 used was changed from 216.7 parts by mass to 166.7 parts by mass, and 15 parts by mass of epoxy resin 4 was used.

Preparation example 4

A thermosetting adhesive composition (X-4) was obtained in the same manner as in preparation example 1, except that 28 parts by mass of epoxy resin 5 (epoxy equivalent: 275g/eq., melt viscosity at 150 ℃ C., 27dPa · s, solid state (25 ℃ C.), softening point 101 ℃ C.) was used in place of epoxy resin 2.

(example 1)

The thermosetting adhesive composition (X-1) obtained in preparation example 1 was added with 051DU40 (thermal expansion microcapsules manufactured by Japan Fillite Co., ltd., expansion starting temperature 108 to 113 ℃ C.) as an expanding agent in an amount of 15 parts by mass based on 100 parts by mass of the solid content of the thermosetting resin contained in the thermosetting resin composition (X-1), and stirred for 10 minutes by a dispersion stirrer, thereby obtaining an expandable thermosetting adhesive composition (Y-1).

Next, the expandable thermosetting adhesive composition (Y-1) was applied to the surface of a release liner (obtained by peeling off one side of a polyethylene terephthalate film having a thickness of 50 μm with an organosilicon compound) using a bar-shaped metal applicator so that the thickness after drying was 50 μm.

Then, the coated product was put into a dryer at 85 ℃ and dried for 5 minutes, thereby obtaining a sheet-like expandable thermosetting adhesive layer (Z-1) having a thickness of 50 μm.

(example 2)

An expandable thermosetting adhesive layer (Z-2) in a sheet form having a thickness of 50 μm was obtained in the same manner as in example 1, except that the thermosetting adhesive composition (X-2) obtained in preparation example 2 was used.

(example 3)

An expandable thermosetting adhesive layer (Z-3) in a sheet form having a thickness of 50 μm was obtained in the same manner as in example 1, except that the thermosetting adhesive composition (X-3) obtained in preparation example 3 was used.

Comparative example 1

An expandable thermosetting adhesive layer (Z-4) in a sheet form having a thickness of 50 μm was obtained in the same manner as in example 1, except that the thermosetting adhesive composition (X-4) obtained in preparation example 4 was used.

[ method for measuring expansion ratio of adhesive tape ]

The thickness of the pressure-sensitive adhesive tapes produced in examples 1 to 3 and comparative example 1 was measured by using a thickness meter. Next, the adhesive tape was left to stand at 130 ℃ for 10 minutes to swell, and the thickness of the swollen adhesive tape was measured using a thickness meter.

The expansion ratio is a ratio of the thickness of the adhesive tape after the placement to the thickness of the adhesive tape before the placement of the adhesive tape in an environment at 130 degrees celsius for 10 minutes (before the expansion) calculated according to the following formula.

[ thickness of adhesive tape after the placement (after expansion)/thickness of adhesive tape before the placement (before expansion) ]. Times.100

[ method for measuring initial adhesion of thermosetting adhesive layer ]

The 180 degree peel adhesion was measured according to JIS Z0237. The release paper on one side of the tape was peeled off and backed with a 25 μm thick polyethylene terephthalate film. In this case, in order to prevent the adhesive tape from falling off from the polyethylene terephthalate, the pressure bonding was performed by applying a load of 1kN at 60 ℃ for 1 minute in a state where the adhesive tape and the polyethylene terephthalate were bonded.

The linered adhesive tape was sufficiently cooled at 23 ℃ and cut into a width of 10mm, and then the release liner on the other side of the adhesive tape was peeled off, and the adhesive layer was attached to the degreased smooth surface of the SUS plate and reciprocated 1 time by a 2kg roller to obtain a sheet as a test piece.

The test piece was left to stand at 23 ℃ for 1 hour, and then a Tensilon tensile tester [ manufactured by Tensilon corporation, model No.: RTM-100] to measure the adhesive force when the adhesive tape constituting the above test piece was peeled from the SUS plate at a speed of 300 mm/min in the 180 degree direction.

[ evaluation of initial adhesiveness of Expandable thermosetting adhesive layer ]

The adhesive tape produced in examples 1 to 3 and comparative example 1 was cut into a square of 10mm × 10 mm. The adhesive tape thus cut was peeled off from the release film at 23 ℃ and attached to a degreased SUS plate having a smooth surface and a width of 50mm, a length of 70mm and a thickness of 2 mm.

Then, the SUS plate was erected at 23 ℃ at 90 ° with respect to the floor, and the adhesive tape attached to the SUS plate was lifted up to a height of 10cm from the floor and was allowed to fall vertically. This operation was repeated 10 times, and the case where the above-described misalignment of the adhesive tape did not occur was regarded as "good", and the case where the misalignment of the adhesive tape occurred was regarded as "x".

[ method for measuring shear adhesion Strength ]

2 smooth-surfaced aluminum plates of 15mm in width, 70mm in length and 0.5mm in thickness were degreased, and as shown in FIG. 1,2 spacers were arranged in parallel at intervals of 12mm at the end of the upper surface (C1-1) of one aluminum plate (C1) and bonded. The above-mentioned spacer used was one prepared in such a manner that the total thickness of the spacer and the adhesive tape used in the bonding was increased by 50 μm relative to the total thickness of the adhesive tape.

Next, an adhesive tape cut to a size of 10mm × 10mm was attached to the upper surface (C1-1) side of the aluminum plate (C1) and between the 2 spacers, and pressure-bonded using a 2kg hand roller. Next, another aluminum plate (C2) (width 15mm × length 70mm × thickness 0.5 mm) having a degreased smooth surface was placed on the upper surface of the adhesive tape, and fixed by a jig. The fixed sheet was heated at 130 ℃ for 30 minutes, and then left to cool at 23 ℃ for 30 minutes. Next, the end portions of the 2 aluminum plates were clamped by using a sheet from which the jig was removed as a test piece, and a Tensilon tensile tester [ manufactured by a & D, model: RTM-100], and the adhesive strength in the shear direction was measured when a tensile test was performed at 10 mm/min in the 180-degree direction.

[ TABLE 1]

Description of the symbols

1. Aluminum plate (C1)

2. Aluminum plate (C2)

3. Spacer member

4. Adhesive tape of the invention

5. The gap between the adhesive tape of the present invention and the aluminum plate (c 2)

6. Expandable thermosetting adhesive layer

7. Adhesive layer

8. A substrate.

Claims

1. An adhesive tape, which is characterized in that,

the adhesive tape has an expandable thermosetting adhesive layer (A) which expands due to external stimulus on at least one surface thereof, and the expandable thermosetting adhesive layer (A) has a 180-degree peel adhesion at 23 ℃ of 0.1N/20mm or more,

the expandable thermosetting adhesive layer (A) is formed by using an adhesive composition (a) containing a thermosetting resin,

the thermosetting resin contains an epoxy resin in an amount of 80% by mass or more relative to the total amount of the thermosetting resin,

the epoxy resin comprises an epoxy resin (a 1) having an epoxy equivalent of 100 to 450g/eq in a liquid state at 25 ℃, an epoxy resin (a 2) having a softening point of 15 to 100 ℃ and a melt viscosity of 0.01 dPas or more and 20 dPas or less at 150 ℃ and an epoxy equivalent of 162 to 2000g/eq, and an epoxy resin (a 3) having an epoxy equivalent of 2000g/eq or more,

the content of the epoxy resin (a 1) is 1 to 50 mass% based on the total amount of the thermosetting resin,

the content of the epoxy resin (a 2) is 5 to 50% by mass relative to the total amount of the thermosetting resin,

the content of the epoxy resin (a 3) is 40 to 94% by mass based on the total amount of the thermosetting resin.

2. The adhesive tape according to claim 1, wherein,

the stimulus is heat.

3. The adhesive tape according to claim 1 or 2,

the expansion ratio in the thickness direction of the expandable thermosetting adhesive layer (a), i.e., [ thickness of the expandable thermosetting adhesive layer (a') after heating/thickness of the expandable thermosetting adhesive layer (a) before heating ] × 100 is 150% or more.

4. The adhesive tape according to claim 1 or 2,

the expandable thermosetting adhesive layer (A) is a layer containing a thermosetting resin and a thermal expansion capsule having an expansion initiation temperature in the range of 50 to 200 ℃.

5. The adhesive tape according to claim 1 or 2,

the adhesive tape has the expandable thermosetting adhesive layer (a) on both surfaces thereof.

6. The adhesive tape according to claim 1 or 2,

the adhesive tape is composed of a single layer of the expandable thermosetting adhesive layer (a).

7. The adhesive tape according to claim 1 or 2,

use of the adhesive tape for filling a gap in an adherend (C1) or a gap between the adherend (C1) and an adherend (C2).

8. An article characterized in that it is, in particular,

the article is bonded or filled in a gap of an adherend (C1) or a gap between the adherend (C1) and an adherend (C2) via the expanded product of the adhesive tape according to any one of claims 1 to 7.

9. A method of manufacturing an article, characterized in that,

the article is bonded to or filled in a gap of an adherend (C1) or a gap between the adherend (C1) and an adherend (C2) via the expanded product of the adhesive tape according to any one of claims 1 to 7, and the method for producing the article comprises the steps of:

a step [1] of attaching the adhesive tape according to any one of claims 1 to 7 to a site (C1-1) constituting an adherend (C1);

a step [2] in which a stimulus is applied to the expandable thermosetting adhesive layer (A);

a step [3] in which the expansive thermosetting adhesive layer (A) expands due to the stimulus to form an expansive thermosetting adhesive layer (A'); and

and (4) a step of applying the expanded thermosetting adhesive layer (A') constituting the adhesive tape to the other part (C1-2) constituting the adherend (C1) or the other adherend (C2).