JP2021143266A - Adhesive tape and its application method - Google Patents

Abstract

To provide an adhesive tape that can be easily peeled without an adhesive deposit when needed and can suppress the deterioration of a cement-based structure.SOLUTION: A base material 11, an adhesive layer 12 and a functional layer 13 are provided in this order. The functional layer 13 includes thermally expansive particles and a tacky resin. The expansion magnification when the thermal expansion particles are heated to 60°C or higher is twice or higher and 150 times or smaller to the volume of the thermal expansion particle at 23°C. The adhesive force on the adhesive layer side to the cement-based structure having the surface roughness Ra of 100 μm or smaller is 6 N/10 mm or larger when measured in an environment of 23°C and relative humidity of 50%, as 180° peel force measured in accordance with JIS Z 0237 and 1 N/10 mm or smaller when measured in an environment of 70°C and relative humidity of 5% or lower. The tackiness on the functional layer side is 5 or larger as the ball number in the ball tack test defined in JIS Z 0237.SELECTED DRAWING: Figure 2

Description

The present application relates to an adhesive tape that can be easily applied to a cracked cement-based structure at the time of inspection, can be peeled off when necessary, and can prevent the cracks of the cement-based structure from spreading during the construction, and a method of using the adhesive tape.

Concrete structures used for bridges, tunnels, etc. may crack over time due to fatigue, salt damage, alkaline aggregate reaction, and the like. If a long period of time elapses in a cracked state, rainwater, carbon dioxide, etc. will enter deep into the concrete from the cracked part, and the reinforcing bars will corrode, reducing the strength of the concrete itself and causing serious accidents such as the collapse of bridges and tunnels. there is a possibility. Under such circumstances, a framework has been established in which inspections of infrastructure such as concrete structures are carried out reliably once every five years.

Although it depends on the environmental conditions, leaving the cracks unattended means the progress of deterioration of the concrete, so it is desirable to be able to take some measures. Therefore, it is necessary to take repair measures at an early stage when the concrete is cracked. As a method for repairing cracks in concrete, a base treatment agent consisting of an aqueous solution containing an alkali metal silicate is applied to penetrate the inside of the cracks, and then a putty material in which an inorganic filler is dispersed is filled inside the cracks. (For example, Patent Document 1) and a method of applying a paste containing a self-repairing material along a cracked portion of concrete (for example, Patent Document 2) have been proposed.

Further, there is Patent Document 3 as a technical document related to the invention disclosed in the present application.

JP-A-2010-001195 Japanese Unexamined Patent Publication No. 2013-014453 JP-A-2017-222799

In the method of directly filling or applying the repair material to the cracked portion as described in Patent Documents 1 and 2, a large-scale method such as providing a scaffolding for work or requiring repair work by a specialist is required. Construction is required. On the other hand, in the maintenance of concrete structures in local governments, the repair cost cannot be secured sufficiently, and the judgment of the deterioration grade due to cracks becomes ambiguous. There was a problem that cracks could not be dealt with on the spot.

This application was made to solve the above problems, and can be easily installed by an inspector who finds a crack in a cement-based structure, and can be easily peeled off without adhesive residue if necessary. Provided are an adhesive tape capable of suppressing deterioration of a structure and a method of using the adhesive tape.

The adhesive tape of the present invention is an adhesive tape containing a base material, an adhesive layer, and a functional layer in this order. The adhesive layer contains an adhesive, and the functional layer is tacked with heat-expandable particles. The expansion ratio when the heat-expandable particles are heated to 60 ° C. or higher, which contains an adhesive resin, is 2 times or more and 150 times or less with respect to the volume of the heat-expandable particles at 23 ° C., and has a surface roughness. When the adhesive force on the adhesive layer side of a cement-based structure having Ra of 100 μm or less is measured in an environment of a temperature of 23 ° C. and a relative humidity of 50% as a 180 ° peeling force measured according to the provisions of JIS Z0237. , 6N / 10mm or more, 1N / 10mm or less when measured in an environment with a temperature of 70 ° C. and a relative humidity of 5% or less, and the tackiness on the functional layer side is a ball tack test specified in JIS Z0237. The ball number in is 5 or more.

Further, the method of using the adhesive tape of the present invention includes a step of preparing the adhesive tape of the present invention, a step of attaching the functional layer side of the adhesive tape to a deteriorated portion of a cement-based structure, and a step of attaching the adhesive tape. A step of leaving the bonded cement-based structure in a natural environment for a certain period of time, and a step of heating the adhesive tape to 60 ° C. or higher after the leaving to reduce the adhesive strength of the adhesive tape. The step of peeling the adhesive tape having reduced adhesive strength from the cement-based structure is included.

According to the present application, an inspector of a cement-based structure can attach it by a simple method immediately after the inspection, can easily peel it off without adhesive residue when necessary, and sufficiently suppress deterioration of the cement-based structure due to cracks. Possible adhesive tapes and methods of use thereof can be provided.

FIG. 1 is a schematic external view A and a cross-sectional view B thereof showing an example of the heat-expandable particles of the embodiment. FIG. 2 is a schematic cross-sectional view showing an example of the adhesive tape of the embodiment. FIG. 3 is a schematic cross-sectional view showing another example of the adhesive tape of the embodiment. FIG. 4 is a schematic cross-sectional view showing an example of a state in which the adhesive tape of the embodiment is attached to a cracked portion of a cement-based structure. FIG. 5 is a schematic cross-sectional view showing an example of a state in which the adhesive tape of the embodiment bonded to the cement-based structure is heated. FIG. 6 is a schematic cross-sectional view showing an example of a state in which the adhesive tape of the embodiment is peeled off from the cracked portion of the cement-based structure. FIG. 7 is a schematic cross-sectional view showing an example of a state in which the conventional adhesive tape is peeled off from the cracked portion of the cement-based structure.

(Adhesive tape)
An embodiment of the adhesive tape disclosed in the present application will be described. The adhesive tape of the present embodiment includes a base material, an adhesive layer, and a functional layer in this order. The adhesive layer contains an adhesive, and the functional layer contains heat-expandable particles and a tacky resin. Including, the expansion ratio when the heat-expandable particles are heated to 60 ° C. or higher is 2 times or more and 150 times or less with respect to the volume of the heat-expandable particles at 23 ° C., and the surface roughness Ra is 100 μm or less. The adhesive force on the adhesive layer side to the cement-based structure of is 6 N / 10 mm when measured in an environment of a temperature of 23 ° C. and a relative humidity of 50% as a 180 ° peeling force measured according to the provisions of JIS Z0237. As described above, when measured in an environment where the temperature is 70 ° C. and the relative humidity is 5% or less, the tackiness is 1N / 10 mm or less, and the tackiness on the functional layer side is the ball number in the ball tack test specified in JIS Z0237. 5 or more.

By including an adhesive in the adhesive layer, the adhesive tape can follow an uneven surface such as a cement-based structure, and can reliably adhere the adhesive tape and the cement-based structure to the outside air in a wide temperature range. Can block contact with cement-based structures. _{As a result, it is possible to suppress the intrusion of rainwater and CO 2} from deteriorated parts such as cracks in the cement-based structure, and it is possible to prevent salt damage and alkali-aggregate reaction in the cement-based structure. Even if reinforcing bars or the like are present, corrosion of the reinforcing bars or the like can be prevented, and protection performance against cracked cement-based structures can be ensured.

Further, since the functional layer of the adhesive tape contains heat-expandable particles whose expansion ratio when heated to 60 ° C. or higher is 2 times or more and 150 times or less with respect to the volume of 23 ° C., the adhesive By heating the tape to 60 ° C. or higher, the adhesive strength of the adhesive tape can be reduced, and the adhesive from the cement-based structure does not leave a residue (adhesive residue) on the cement-based structure side. The tape can be peeled off. Specifically, the adhesive force on the adhesive layer side with respect to a cement-based structure having a surface roughness Ra of 100 μm or less is 180 ° peeling force measured according to the provisions of JIS Z0237, and the temperature is 23 ° C. and the relative humidity is 50%. When measured in the above environment, it can be 6N / 10 mm or more, and the adhesive strength can be maintained under the normal environment. Further, the adhesive force on the adhesive layer side with respect to a cement-based structure having a surface roughness Ra of 100 μm or less is measured according to the provisions of JIS Z0237 as a 180 ° peeling force in an environment where the temperature is 70 ° C. and the relative humidity is 5% or less. When measured below, it can be 1N / 10 mm or less, and by heating the adhesive tape to 60 ° C or higher, the adhesive strength can be reduced, and if necessary, it can be easily peeled off without adhesive residue. ..

Further, since the functional layer of the adhesive tape contains a tacky resin, the initial adhesiveness immediately after the adhesive tape is attached to the cement-based structure is high, and the end portion of the adhesive tape is peeled off immediately after the attachment. Can be prevented. Specifically, the tackiness of the adhesive tape on the functional layer side can be set to 5 or more as the ball number in the ball tack test specified in JIS Z0237.

Further, since the adhesive tape has a base material, the color of the base material can be adjusted in various ways so that the inspector can easily adjust the color of the base material immediately after the inspection without spoiling the aesthetic appearance when the adhesive tape is attached to the cement-based structure. It can be attached by any method, and can be easily peeled off without adhesive residue when necessary, and deterioration of cement-based structures due to cracks can be suppressed.

Further, at least one selected from the adhesive layer and the functional layer preferably contains a material that can be heated by an external stimulus. As a result, the adhesive tape can be heated by a relatively simple heating method such as electromagnetic induction heating or microwave heating as heating by an external stimulus to reduce the adhesive strength of the adhesive tape, and is cement-based. The adhesive tape can be peeled off from the structure without any residue (adhesive residue).

In the adhesive tape, the base material and the adhesive layer are usually in contact with each other, and the adhesive layer and the functional layer are in contact with each other.

In the present application, the cement-based structure includes a concrete structure and a mortar structure.

Hereinafter, each component of the adhesive tape of the present embodiment will be described.

<Base material>
The base material used for the adhesive tape of the present embodiment is a base material for forming an adhesive layer and a functional layer, which will be described later.

Examples of the base material include a resin base material, and the resin base material specifically includes a polyolefin resin (low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra-low density). Density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypoly, polybutene, polymethylpentene, etc.), ethylene-vinyl acetate copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- ( Meta) Acrylic acid ester copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, polyurethane resin, polyester resin (polyethylene terephthalate: PET, polyethylene naphthalate: PEN, polybutylene terephthalate: PBT, polybutylene Naphthalate: PBN, etc.), Polyethylene resin, Polyamide resin, Polyether ketone resin, Polyether resin, Polyether sulfone resin, Polystyrene resin (polystyrene, etc.), Polyvinyl chloride resin, Polyvinylidene chloride Constituent materials such as resins, polyvinyl alcohol-based resins, polyvinyl acetate-based resins, vinyl chloride-vinyl acetate copolymers, polycarbonate-based resins, fluorine-based resins, silicone-based resins, cellulose-based resins, and crosslinked products of these resins. Examples thereof include a base material composed of. Among these, polyethylene terephthalate (PET) is more preferable in terms of mechanical properties and price. As these constituent materials, one kind or two or more kinds can be used. In addition, the constituent material may have a functional group, if necessary. Further, a functional monomer or a modifying monomer may be grafted on the constituent material.

The surface of the base material may be subjected to a known surface treatment in order to improve the adhesion to the adjacent adhesive layer. Specific examples of the surface treatment include corona discharge treatment, ozone exposure treatment, high-voltage impact treatment, ionizing radiation treatment, and the like. Further, the base material may be subjected to a coating treatment (silicone treatment or the like), a primer treatment, a mat treatment, a cross-linking treatment or the like with an undercoating agent.

The form of the base material may be a single layer or a laminated body in which two or more layers are laminated. Further, in the above-mentioned base material, if necessary, known aids such as fillers, flame retardants, deterioration inhibitors, antistatic agents, softeners, ultraviolet absorbers, antioxidants, plasticizers, surfactants and the like are added. The agent may be added.

The thickness of the base material is not particularly limited, but is preferably 30 to 300 μm, and more preferably 50 to 150 μm. If the thickness of the base material is less than 30 μm, the strength of the adhesive tape itself of the present embodiment tends to be insufficient, and if it exceeds 300 μm, the cost increases.

<Resin layer>
In order to ensure the weather resistance and chemical resistance of the base material, it is preferable to arrange the resin layer on the main surface opposite to the main surface of the base material on which the adhesive layer and the functional layer described later are formed. .. As the resin constituting the resin layer, a fluorine-based resin and a silicone-based resin are preferable.

<Adhesive layer>
The adhesive layer used for the adhesive tape of the present embodiment is for imparting the original adhesive force to the adhesive tape, and more specifically, the adhesive layer for a cement-based structure having a surface roughness Ra of 100 μm or less. The adhesive strength on the adhesive layer side of the tape should be 6N / 10mm or more when measured in an environment with a temperature of 23 ° C and a relative humidity of 50% as a 180 ° peeling force measured according to the provisions of JIS Z0237. It is to be provided.

The pressure-sensitive adhesive contains at least one pressure-sensitive adhesive component selected from the group consisting of natural rubber-based pressure-sensitive adhesive components, synthetic rubber-based pressure-sensitive adhesive components, silicone-based pressure-sensitive adhesive components, acrylic-based pressure-sensitive adhesive components, and polyester-based pressure-sensitive adhesive components.

[Natural rubber adhesive component]
Examples of the natural rubber-based adhesive component include rubber made of cis-1,4-polyprene, which is collected only from the resin solution of a rubber tree (Hebea braziliensis).

[Synthetic rubber adhesive component]
Examples of the synthetic rubber-based adhesive component include styrene / butadiene rubber, isoprene rubber, butadiene rubber, chloroprene rubber, acrylonitrile / butadiene rubber, butyl rubber, ethylene / propylene rubber, ethylene / propylene / diene rubber, and the like.

[Silicone adhesive component]
Examples of the silicone-based adhesive component include an addition reaction type silicone-based adhesive component and a peroxide-curable silicone-based adhesive component, and these may be used alone or in combination.

The addition reaction type silicone-based adhesive component is not particularly limited, but for example, KR3700, KR3701, X-40-3237-1, X-40-3240, X-40-manufactured by Shin-Etsu Chemical Co., Ltd. 3291-1, X-40-3229, X-40-3270, X-40-3306 (all trade names), TSR1512, TSR1516, XR37-B9204 (all trade names) manufactured by Momentive Performance Materials. , SD4584, SD4585, SD4560, SD4570, SD4600PFC, SD4593 (all trade names) manufactured by Toray Dow Corning.

The above-mentioned addition reaction type silicone-based adhesive component is used together with a cross-linking agent, and the cross-linking agent is not particularly limited. For example, X-92-122 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd., Momentive Performance. -CR50 (trade name) manufactured by Materials, BY24-741 (trade name) manufactured by Toray Dow Corning, etc. can be used.

The peroxide-curable silicone-based adhesive component is not particularly limited, but for example, KR100 and KR101-10 (both are trade names) manufactured by Shin-Etsu Chemical Co., Ltd. and Momentive Performance Materials Co., Ltd. YR3340, YR3286, PSA610-SM, XR37-B6722 (all trade names), SH4280 (trade name) manufactured by Toray Dow Corning, etc. can be mentioned.

The peroxide-curable silicone-based adhesive component is used together with a cross-linking agent, and the cross-linking agent is not particularly limited, but for example, benzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5. -Di (t-butylperoxy) hexane, 1,1'-di-t-butylperoxy-3,3,5-trimethylencyclohexane, 1,3-di- (t-butylperoxy) -diisopropylbenzene and the like. Be done.

[Acrylic adhesive component]
Examples of the acrylic adhesive component include those obtained by copolymerizing a (meth) acrylic acid ester monomer. Examples of the (meth) acrylic acid ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. , (Meta) isooctyl acrylate, (meth) nonyl acrylate, (meth) isononyl acrylate and the like. In addition, (meth) acrylic acid ester monomers contain functional groups such as (meth) acrylic acid, crotonic acid, fumaric acid, itaconic acid, and (maleic anhydride) maleic acid, vinyl acetate, acrylonitrile, styrene, and (meth). 2-Hydroxyethyl acrylate, 2-methylolethyl acrylamide and the like may be added and copolymerized.

[Polyester adhesive component]
Examples of the polyester-based adhesive component include those obtained by polycondensing a polyvalent carboxylic acid (for example, a dicarboxylic acid) and a polyalcohol (for example, a diol). Examples of the dicarboxylic acid include adipic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, dodecenyl anhydride amber acid, fumaric acid, amber acid, dodecanedioic acid, and hexahydro. Alipid or alicyclic dicarboxylic acids such as phthalic anhydride, tetrahydrophthalic anhydride, maleic acid, maleic anhydride, itaconic acid, and citraconic acid, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid. Examples thereof include 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, and 4,4'-diphenyletherdicarboxylic acid. Examples of the diol include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1 , 4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1 , 5-Pentanediol, 2-ethyl-2-butylpropanediol, 1,9-nonanediol, 2-methyloctanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol, 1,2-cyclohexanedi Examples thereof include aliphatic glycols such as methanol.

The pressure-sensitive adhesive preferably contains a cross-linking agent together with the pressure-sensitive adhesive component, and may further contain a cross-linking accelerator, a filler, a softening agent, a tackifier, an antiaging agent, and the like, if necessary.

[Crosslinking agent]
As the above-mentioned cross-linking agent, sulfur, thiuram-based tetramethylthiuram sulfide (TMTD), dipentamethylene thiuram tetrasulfide (DPTT), p-quinonedioxime and the like are generally used, and among them, TMTD is used. It is desirable to do.

The amount of the cross-linking agent added is required to be at least 0.05 parts by mass or more with respect to 100 parts by mass of the pressure-sensitive adhesive component, and is preferably 0.1 to 10 parts by mass. If the amount added is less than 0.05 parts by mass, the degree of cross-linking is low, and the cross-linking step tends to take time when producing the pressure-sensitive adhesive. Further, since the cohesive force of the adhesive component is reduced, there is a tendency that adhesive residue is generated on the adherend when the adhesive tape is peeled off. On the other hand, if the addition amount exceeds 10 parts by mass, the degree of cross-linking tends to be too high, and the initial kneading time tends to be long.

[Crosslink accelerator]
As the cross-linking accelerator, thiuram-based, thiazole-based, dithiocarbamate and the like are used, and they can be used in combination with each other. Since the amount of the cross-linking accelerator added is adjusted to 100 parts by mass of the pressure-sensitive adhesive component according to the type and amount of the cross-linking agent added, it is usually preferably used in the range of 2 to 10 parts by mass.

[filler]
The filler is used to give the pressure-sensitive adhesive an arbitrary color, and is also used to enhance the reinforcing property of the pressure-sensitive adhesive component. As the filler, calcium carbonate, titanium oxide, clay, silica, talc, carbon black and the like can be used, but it is particularly desirable to use calcium carbonate and titanium oxide. Two or more kinds of the above fillers may be used in combination.

The amount of the filler added is required to be at least 60 parts by mass or more with respect to 100 parts by mass of the pressure-sensitive adhesive component, and is particularly preferably 70 to 250 parts by mass. If the amount added is less than 60 parts by mass, the cohesive force of the adhesive component decreases, and if it exceeds 250 parts by mass, the rubber elasticity is inferior and the Mooney viscosity becomes too high, which is not preferable as a raw material for the adhesive.

[Softener]
The softener is usually used together with the filler, and as the softener, process oil, liquid polybutene, liquid polybutadiene and the like can be used, but the process oil is used because the effect of the adhesive layer can be preferably obtained. It is desirable to use. The amount of the softener added is required to be at least 30 parts by mass or more with respect to 100 parts by mass of the pressure-sensitive adhesive component, and is preferably 30 to 400 parts by mass. If the amount added is less than 30 parts by mass, the adhesive component and the filler are difficult to be uniform and the processability is poor. If the amount added exceeds 400 parts by mass, the Mooney viscosity tends to be too low. be.

[Adhesive]
The tackifier is not particularly limited, and is styrene resin, xylene resin, aromatic-modified terpene resin, terpene phenol resin, aliphatic petroleum resin, aromatic petroleum resin, and aliphatic aromatic resin. Petroleum resin, Kumaron-inden resin, phenol-based resin, disproportionate rosin resin, rosin-modified phenol resin and the like can be used. The amount of the pressure-sensitive adhesive added is preferably 15 to 70 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive component. If the amount added is less than 15 parts by mass, the desired adhesive strength tends not to be exhibited, and if the amount added exceeds 70 parts by mass, the initial adhesiveness tends to decrease when used under low temperature conditions. be.

[Anti-aging agent]
In order to improve the aging resistance of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, it is effective to add an anti-aging agent. As the anti-aging agent, for example, phenol-based, amine-based, benzimidazole-based, sulfur-based, and phosphorus-based anti-aging agents can be used, but are not particularly limited thereto. Among these, it is preferable to use a phenol-based or sulfur-based antiaging agent. Only one of these anti-aging agents may be used, or two or more thereof may be combined.

The main factor of the aging of the pressure-sensitive adhesive is the oxidative deterioration of the pressure-sensitive adhesive components constituting the pressure-sensitive adhesive. Anti-aging agents are classified according to the difference in the mechanism of suppressing oxidative deterioration of adhesive components, and are classified into radical chain prohibition type and peroxide decomposition type.

The radical chain-prohibited antiaging agent has a phenolic "-OH" or "-NH" in the molecule that easily reacts with radicals. Then, it has the effect of stopping the autoxidation by reacting with radicals and the like generated in the polymer due to deterioration and inactivating it. Phenolic and amine-based anti-aging agents are radical chain-prohibited types.

On the other hand, the peroxide decomposition type antiaging agent is typically a compound containing sulfur or phosphorus or a benzimidazole compound, which decomposes hydroperoxide (ROOH) generated in the polymer and is a stable substance (ROH, etc.). ).

As the anti-aging agent, a non-contaminating phenol-based anti-aging agent is desirable in consideration of coloring the pressure-sensitive adhesive to an arbitrary color. The amount of the antiaging agent added is preferably 2 to 10 parts by mass with respect to 100 parts by mass of the adhesive component. If the amount added is less than 2 parts by mass, the pressure-sensitive adhesive tends to deteriorate, and even if the amount added exceeds 10 parts by mass, the effect of addition does not change significantly.

The thickness of the adhesive layer can be determined according to the ability to follow the uneven surface of the cement-based structure, and is not particularly limited, but is preferably 200 to 5000 μm, more preferably 500 to 1000 μm. If the thickness of the adhesive layer is less than 200 μm, it tends to be unable to follow the irregularities on the cracked surface of the cement-based structure, and conforms to the JIS Z0237 regulations in an environment with a temperature of 23 ° C and a relative humidity of 50%. The 180 ° peel force measured in the above method tends not to be 6N / 10mm. On the other hand, even if the thickness of the adhesive layer exceeds 5000 μm, there is no significant change in the followability to the unevenness of the cracked surface, but the cement-based structure tends to have adhesive residue at the time of peeling.

<Functional layer>
The functional layer used for the adhesive tape of the present embodiment has a function of reducing the adhesive strength of the adhesive tape when the adhesive tape is heated to 60 ° C. or higher, and immediately after the adhesive tape is attached to a cement-based structure. This is for imparting a function of enhancing the initial adhesiveness of the product. The functional layer contains heat-expandable particles and a tacky resin.

[Thermal expandable particles]
The heat-expandable particles are components that impart a function of lowering the adhesive force of the adhesive tape to the functional layer when the adhesive tape is heated to 60 ° C. or higher. The above-mentioned thermally expandable particles are particularly applicable as long as the expansion coefficient when heated to 60 ° C. or higher is 2 times or more and 150 times or less, preferably 5 times or more and 30 times or less with respect to the volume of 23 ° C. Although the composition is not limited, thermally expandable particles containing an outer shell made of a thermoplastic resin and a hydrocarbon having 5 to 12 carbon atoms contained in the outer shell are preferably used.

FIG. 1A is a schematic external view showing an example of the heat-expandable particles used in the present embodiment, and FIG. 1B is a cross-sectional view of FIG. 1A. In FIG. 1, the heat-expandable particles 1 include an outer shell 2 made of a thermoplastic resin, and a hydrocarbon 3 having 5 to 12 carbon atoms is contained in the outer shell 2. Here, when the heat-expandable particles 1 are heated, the thermoplastic resin constituting the outer shell 2 of the heat-expandable particles 1 is first started to soften, and at the same time, the contained hydrocarbons 3 are gasified. Once started, the internal pressure of the outer shell 2 rises, and the thermally expandable particles 1 begin to expand. When the heat-expandable particles 1 are heated to 60 ° C. or higher, the expansion coefficient of the heat-expandable particles 1 becomes 2 times or more and 150 times or less with respect to the volume of 23 ° C. It is considered that the adhesive tape is covered with the heat-expandable particles 1, and as a result, the contact area between the adhesive layer of the adhesive tape and the adherend (cement-based structure) is reduced, and the adhesive strength of the adhesive tape is reduced.

Examples of the thermoplastic resin constituting the outer shell of the heat-expandable particles include a polyolefin resin, a vinyl chloride resin, a vinylidene chloride resin, an acrylic resin, an acrylonitrile resin, a polyacetal resin, a polycarbonate resin, and a polyvinyl. Examples thereof include butyral resin, polyvinyl acetate resin, polyvinyl alcohol resin and the like.

Further, the hydrocarbon having 5 to 12 carbon atoms contained in the outer shell of the thermally expandable particles is not particularly limited as long as it is a low boiling point hydrocarbon that is liquid at room temperature and vaporizes at 60 ° C. or higher. ..

The average particle size of the heat-expandable particles is not particularly limited, but for example, those having a diameter of 5 to 50 μm are used. The film thickness of the outer shell is also not particularly limited, but for example, a film thickness of 2 to 15 μm is used. Further, the expansion start temperature of the thermally expandable particles is preferably 60 to 100 ° C. This is because it is relatively easy to heat the adhesive tape of the present embodiment to 60 to 100 ° C.

Specifically, the heat-expandable particles include, for example, the heat-expandable microcapsules "Matsumoto Microsphere" (trade name) manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd. and the heat-expandable microcapsules "Expansel" manufactured by Nippon Philite Co., Ltd. (Product name), heat-expandable fine particles "Dieform" (trade name) manufactured by Dainichi Seika Kogyo Co., Ltd. can be used.

The content of the heat-expandable particles in the functional layer of the adhesive tape is preferably 1 to 35 parts by mass and more preferably 3 to 15 parts by mass with respect to 100 parts by mass of the tacky resin. .. If the content is less than 1 part by mass, the adhesive strength tends not to decrease even if the adhesive tape is heated to 60 ° C. or higher, and peeling from the cement-based structure becomes difficult. Further, when the content is more than 35 parts by mass, the adhesive strength of the adhesive tape at room temperature tends to decrease.

[Tacking resin]
The tacky resin is a component that imparts a function to the functional layer to enhance the initial adhesiveness immediately after the adhesive tape is attached to the cement-based structure. The tacky resin is not particularly limited as long as the tackiness on the functional layer side of the adhesive tape can be 5 or more as the ball number in the ball tack test specified in JIS Z0237, and is not particularly limited. Selected from the group consisting of polyolefin resins, polyvinyl chloride resins, acrylic resins, polyester resins, fluorine resins, aramid resins, natural rubber resins, synthetic rubber resins, silicone resins, and urethane resins. At least one kind of resin can be used.

The thickness of the functional layer is not particularly limited, but is usually set to 20 to 100 μm. When the thickness of the functional layer is within the above range, the above-mentioned function of reducing the adhesive strength of the adhesive tape when the adhesive tape is heated to 60 ° C. or higher, and the above-mentioned adhesive tape on a cement-based structure. This is because it can exert a function of enhancing the initial adhesiveness immediately after bonding.

<Materials that can be heated by external stimuli>
As described above, at least one selected from the adhesive layer and the functional layer preferably contains a material that can be heated by an external stimulus. The material capable of heating by the above-mentioned external stimulus is not particularly limited, and examples thereof include a material capable of electromagnetic induction heating, a material capable of microwave heating, and the like. Among these, a material capable of electromagnetic induction heating is particularly preferable. Electromagnetic induction heating is a direct heating method using electromagnetic induction, and can selectively heat only the material to be heated. Further, since the material that can be heated by the external stimulus is contained in the adhesive layer and the functional layer, its form is preferably powder.

[Materials capable of electromagnetic induction heating]
In electromagnetic induction heating, an electric current is passed through the object to be heated to generate heat by electromagnetic induction, so that the object to be heated needs to be a conductor. Therefore, the material capable of electromagnetic induction heating is composed of a conductor. As the conductor, a metal material, a conductive non-metal material, or the like can be used. The metal material is preferably aluminum, iron, copper, silver, gold, nickel, platinum, zinc, lead, stainless steel and the like, and the conductive non-metal material is, for example, carbon black, carbon fiber and graphene. Etc. are preferable.

[Materials that can be heated by microwaves]
Microwave heating generates heat by the molecular motion of the object to be heated and ionic conduction by the action of electromagnetic waves of 300 MHz to 300 GHz, so it is possible to heat dielectrics, conductors, and magnetic materials, but in reality, it is mainly dielectric. Suitable for heating the body. As the dielectric, for example, various synthetic resins; ceramics such as silicon carbide and silicon nitride; mica and the like can be used, and the conductor is a metal material similar to the above-mentioned material capable of electromagnetic induction heating and conductivity. Non-metal materials and the like can be used, and as the magnetic material, for example, iron oxide, various ferrite materials and the like can be used.

The content of the material capable of electromagnetic induction heating or the material capable of microwave heating in the functional layer may be an amount capable of heating above the expansion start temperature of the thermally expandable particles contained in the functional layer of the adhesive tape. The amount is not particularly limited, but for example, it may be 1 to 20 parts by mass with respect to 100 parts by mass of the tacky resin.

Further, the content of the material capable of electromagnetic induction heating or the material capable of microwave heating in the adhesive layer is also an amount capable of heating above the expansion start temperature of the heat-expandable particles contained in the functional layer of the adhesive tape. If this is the case, the content is not particularly limited, but for example, it may be 1 to 20 parts by mass with respect to 100 parts by mass of the adhesive component.

Subsequently, a method for manufacturing the adhesive tape of the present embodiment will be described. The method for producing the adhesive tape of the present embodiment is not particularly limited, but it can be produced, for example, by combining the following steps.
(1) A step of preparing the above-mentioned base material, the pressure-sensitive adhesive layer-forming paint containing the above-mentioned pressure-sensitive adhesive layer component, and the above-mentioned functional layer-forming paint containing the above-mentioned functional layer component (2) A step of applying an adhesive layer forming paint to prepare an adhesive layer and then pasting a release film on the adhesive layer (3) Applying the above functional layer forming paint to another release film with a release film Step of producing a functional layer (4) A step of sticking the functional layer side of the functional layer with a release film to the adhesive layer while peeling off the release film of the adhesive layer.

The adhesive tape produced in the above step is used by peeling off the release film of the above functional layer.

Next, the adhesive tape of this embodiment will be described with reference to the drawings. FIG. 2 is a schematic cross-sectional view showing an example of the adhesive tape of the present embodiment. In FIG. 2, the adhesive tape 10 has an adhesive layer 12 on the base material 11 and a functional layer 13 on the adhesive layer 12. Further, FIG. 3 is a schematic cross-sectional view showing another example of the adhesive tape of the present embodiment. In FIG. 3, the adhesive tape 20 includes an adhesive layer 12 on the base material 11, a functional layer 13 on the adhesive layer 12, and a release sheet 14 on the functional layer 13.

Adhesive tape of the present embodiment, carbon dioxide permeability at 20 ° C. as specified in JIS K7126 is preferably at ^{0.5g / (m 2 · 24hr ·} 1atm) below. When the carbon dioxide transmittance is within the above range, not only carbon dioxide that promotes deterioration of cement-based structures but also chlorine ions, water, oxygen and the like that promote deterioration of cement-based structures can be blocked.

(How to use adhesive tape)
An embodiment of the method of using the adhesive tape disclosed in the present application will be described. The method of using the adhesive tape of the present embodiment includes a step of preparing the adhesive tape previously disclosed in the present application, a step of attaching the functional layer side of the adhesive tape to a deteriorated portion of a cement-based structure, and the above-mentioned adhesive tape. The cement-based structure to which the above-mentioned cement is bonded is left in a natural environment for a certain period of time, and after the leaving, the adhesive tape is heated to 60 ° C. or higher to reduce the adhesive strength of the adhesive tape. The step of peeling the adhesive tape having reduced adhesive strength from the cement-based structure is included.

According to the method of using the adhesive tape of the present embodiment, the adhesive tape can be easily attached to the deteriorated portion of the cement-based structure at room temperature immediately after the inspection of the cement-based structure, and the adhesion can be reliably maintained and required. It can be easily peeled off without adhesive residue by heating according to the above. Further, while the adhesive tape is attached to the deteriorated portion of the cement-based structure, deterioration of the cement-based structure can be prevented, and the durability and fatigue resistance of the adhesive tape itself are high, so that it can be used for a long period of time. It is possible to prevent deterioration of cement-based structures. Further, since the adhesive tape can be colored on the adhesive layer, the color of the adhesive tape itself can be matched with the color of the cement-based structure, so that the aesthetic appearance is not spoiled even if the adhesive tape is attached to the cement-based structure. ..

Further, the adhesive tape used in the present embodiment can follow an uneven surface such as the surface of a cement-based structure by containing an adhesive in the adhesive layer, and the outside air and the cement-based structure come into contact with each other in a wide temperature range. _{It is possible to prevent rainwater and CO 2} from entering from deteriorated parts such as cracks in the cement-based structure, and it is possible to prevent salt damage and alkali aggregate reaction in the cement-based structure. Even if there are reinforcing bars or the like, corrosion of the reinforcing bars or the like can be prevented, and protection performance against cracked cement-based structures can be ensured.

Further, since the functional layer of the adhesive tape contains heat-expandable particles, the adhesive strength of the adhesive tape is lowered by heating the adhesive tape to a temperature equal to or higher than the expansion start temperature of the heat-expandable particles. The adhesive tape can be peeled off from the cement-based structure without forming a residue (adhesive residue) of the adhesive layer on the cement-based structure side. This makes it easy to visually check the size of deteriorated parts such as cracks in cement-based structures, and whether or not full-scale repair work is necessary at that point (usually five years after the previous inspection). Can be judged. Generally, if the deterioration (cracking) of the cement-based structure has progressed significantly at this point, repair work has been carried out, and if the deterioration of the cement-based structure has not progressed, another 5 years. Follow-up is performed.

Further, when at least one of the adhesive layer and the functional layer contains a material that can be heated by an external stimulus, the external stimulus for the heating is, for example, simple electromagnetic induction, microwave irradiation, or the like. The adhesive tape can be heated to reduce the adhesive strength of the adhesive tape by a relatively simple method, and the adhesive tape can be left from the cement-based structure without any residue (adhesive residue). It can be peeled off.

As described above, the thickness of the adhesive layer of the adhesive tape is preferably 200 to 5000 μm, more preferably 500 to 1000 μm. If the thickness of the adhesive layer is less than 200 μm, the adhesive layer cannot follow the unevenness of the surface of the cement-based structure and the adhesive strength tends to decrease. This is because there is no significant change in the followability to.

From the viewpoint of the followability, the total thickness obtained by adding the thickness of the adhesive layer and the thickness of the functional layer of the adhesive tape is 0. It is more preferable that the thickness is 5 times or more.

Subsequently, a method of using the adhesive tape of the present embodiment will be described with reference to the drawings. In the following method of using the adhesive tape, an example in which a concrete structure is used as the cement-based structure will be described. First, as shown in FIG. 4, the functional layer 13 side of the adhesive tape 10 of the present embodiment is attached onto the cracked portion 16 of the concrete 15. At this time, the adhesive tape 10 may be pressed from the base material 11 side.

In the state shown in FIG. 4, leave it for a certain period of time until the next inspection. Since the cracked portion 16 of the concrete 15 is covered with the adhesive tape 10 during the leaving period, for example, 5 years, the deterioration of the concrete does not progress any more, or the progress is slowed down.

Next, for example, at the next inspection five years later, when the adhesive tape 10 contains a material that can be heated by an external stimulus, as shown in FIG. 5, an external stimulus 17 such as electromagnetic induction or microwave irradiation is applied. In addition, the adhesive tape 10 is heated to 60 ° C. or higher. When the adhesive tape 10 does not contain a material that can be heated by an external stimulus, the adhesive tape 10 is heated to 60 ° C. or higher by applying hot air or the like. At that time, since the functional layer 13 of the adhesive tape 10 contains the above-mentioned heat-expandable particles, the adhesive strength of the adhesive tape 10 decreases during the heating. Therefore, even if the adhesive tape 10 is subsequently peeled off from the concrete 15, the adhesive residue of the adhesive layer does not remain on the surface of the concrete 15, as shown in FIG. This makes it easy to check the deteriorated state of concrete. After that, the deterioration status of the entire concrete structure is examined, focusing on the size, depth, etc. of the cracked portion 16 of the concrete 15, and a subsequent repair plan is created. For example, if the cracked portion 16 is significantly enlarged as compared with 5 years before the adhesive tape 10 was attached, an urgent repair plan can be made.

Through the above steps, it is possible to prevent the deterioration of concrete and determine the necessity of repairing the concrete structure by a simple method.

In the above step, an example using the adhesive tape 10 shown in FIG. 2 was shown. However, when the adhesive tape 20 shown in FIG. 3 is used, after the release sheet 14 is peeled off, the functional layer 13 of the adhesive tape 20 is used. The side may be attached to concrete.

Further, FIG. 7 is a schematic cross-sectional view showing an example of a state in which the conventional adhesive tape is peeled off from the cracked portion of the concrete. Since the conventional adhesive tape does not have a functional layer containing thermally expandable particles, the adhesive layer is formed on the surface of the concrete 15 as shown in FIG. 7, not only when the adhesive tape is peeled off as it is at room temperature but also when it is peeled off by heating. Adhesive residue 12a is likely to occur.

Hereinafter, the adhesive tape disclosed in the present application will be described in detail based on examples. However, the following examples do not limit the adhesive tape disclosed in the present application. Moreover, "part" in an Example indicates "mass part".

(Example 1)
<Manufacturing of functional layer forming paint>
First, the following materials were sufficiently dissolved and mixed with a mixer to prepare a functional layer-forming paint.
(1) Regular butyl rubber (manufactured by Exxon, trade name "Butyl 268"): 40 parts (2) Alicyclic saturated hydrocarbon resin (manufactured by Arakawa Chemical Co., Ltd., trade name "Arcon P125"): 25 parts (3) Poly Isobutylene rubber (manufactured by BASF, trade name "Opanol B100"): 25 parts (4) Polybutene (manufactured by Nichiyu Co., Ltd., trade name "Nissan Polybutene 30N"): 10 parts (5) Toluene: 400 parts (6) Thermal expansion Sex particles (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name "Matsumoto Microsphere F-30", average particle diameter: 15 μm, expansion start temperature: 70 ° C.): 12.5 parts (7) Aluminum paste (manufactured by Asahi Kasei Co., Ltd., product) Name "Al paste MH9901", average particle size of contained Al particles: 20 μm): 7.46 parts (Al powder equivalent amount: 5 parts)

<Preparation of adhesive layer forming paint>
Next, the following materials were sufficiently kneaded with a kneader to prepare a pressure-sensitive adhesive layer-forming paint (butyl rubber-based pressure-sensitive adhesive).
(1) Partially cross-linked butyl rubber (manufactured by Shinko Trading Co., Ltd., trade name "Koehler 5215A"): 100 parts (2) Cross-linking agent (manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Barnock GM"): 0.1 parts ( 3) Filler (calcium carbonate): 209.4 parts (4) Softener (process oil): 386.6 parts (5) Adhesive-imparting agent (C5 resin, manufactured by Zeon Corporation, trade name "Quinton A100"): 21.8 copies

<Making adhesive tape>
First, the adhesive layer-forming paint is applied to one side of a base material PET film (manufactured by Toray Industries, Inc., trade name "S-10", thickness: 50 μm) with a calender so as to have a thickness of 500 μm to form an adhesive layer. After forming, a release PET film (manufactured by Nakamoto Pax Co., Ltd., trade name "NS-50-ZW", thickness: 50 μm) was laminated on the adhesive layer at a nip pressure of 0.5 MPa. An adhesive layer laminate composed of a base material PET film / adhesive layer / release PET film was produced.

Next, the above functional layer forming paint is applied to one side of a release PET film (manufactured by Nakamoto Pax Co., Ltd., trade name "NS-50-ZW", thickness: 50 μm), and dried at 110 ° C. for 5 minutes. As a result, a functional layer laminate having a functional layer having a thickness of 50 μm after drying was formed.

Subsequently, while peeling the release PET film from the adhesive layer laminate, the functional layer side of the functional layer laminate is bonded onto the adhesive layer at a nip pressure of 0.5 MPa to adhere the adhesive of Example 1. A tape was made.

(Example 2)
The adhesive tape of Example 2 was produced in the same manner as in Example 1 except that the content of the heat-expandable particles contained in the functional layer-forming paint was changed to 3 parts.

(Example 3)
The adhesive tape of Example 3 was produced in the same manner as in Example 1 except that the content of the heat-expandable particles contained in the functional layer-forming paint was changed to 30 parts.

(Example 4)
The adhesive tape of Example 4 was produced in the same manner as in Example 1 except that the thickness of the functional layer was changed to 30 μm.

(Example 5)
The adhesive tape of Example 5 was produced in the same manner as in Example 1 except that the thickness of the functional layer was changed to 100 μm.

(Example 6)
The adhesive tape of Example 6 was prepared in the same manner as in Example 1 except that the aluminum paste was not added to the functional layer forming paint.

(Comparative Example 1)
The adhesive tape of Comparative Example 1 was produced in the same manner as in Example 1 except that the heat-expandable particles were not added to the functional layer-forming paint.

(Comparative Example 2)
The adhesive tape of Comparative Example 2 was produced in the same manner as in Example 1 except that the content of the heat-expandable particles contained in the functional layer-forming paint was changed to 40 parts.

(Comparative Example 3)
The adhesive tape of Comparative Example 3 was produced in the same manner as in Example 1 except that the thickness of the functional layer was changed to 15 μm.

(Comparative Example 4)
The adhesive tape of Comparative Example 4 was produced in the same manner as in Example 1 except that the thickness of the functional layer was changed to 125 μm.

(Comparative Example 5)
The adhesive tape of Comparative Example 5 was prepared in the same manner as in Example 1 except that the heat-expandable particles and the aluminum paste were not added to the functional layer-forming paint.

Next, the adhesive strength and ball tackiness of the adhesive tapes produced in Examples 1 to 6 and Comparative Examples 1 to 5 were evaluated as follows.

<Adhesive strength to mortar>
First, 22 mortar plates (150 mm × 70 mm × 10 mm) manufactured by Engineering Test Service Co., Ltd. are prepared, and the surface roughness Ra of any three points on the adherend surface of each mortar plate is measured by the laser microscope “VK” manufactured by Keyence Co., Ltd. It was measured at −9710 ”. As a result, the surface roughness Ra of each measurement point of the 22 mortar plates was in the range of 19.0 to 83.2 μm (all 100 μm or less).

Next, for each of the 22 prepared mortar plates, two were assigned to the adherends of Examples 1 to 6 and Comparative Examples 1 to 5.

Subsequently, the release PET film is peeled off from the produced adhesive tape, and the functional layer side of the adhesive tape is attached to the adherend surface of the mortar plate to prepare a measurement sample, and the measurement sample is subjected to a temperature of 23 ° C. and a relative humidity. It was placed in a constant temperature bath set to 50%, and the adhesive strength (180 ° peeling force) was measured according to the provisions of JIS Z0237. Next, another measurement sample prepared in the same manner is placed in a constant temperature bath set to a relative humidity of 5%, heated to a temperature of 70 ° C. by an electromagnetic induction heating device, and then adhered according to JIS Z0237. (180 ° peel force) was measured. However, since the adhesive tapes of Example 6 and Comparative Example 5 do not contain Al particles, they are placed in a constant temperature bath set at a temperature of 70 ° C. and a relative humidity of 5%, and have an adhesive strength according to JIS Z0237. (180 ° peel force) was measured.

<Adhesive strength to concrete>
First, a concrete plate (150 mm × 70 mm × Twenty-two pieces (10 mm) were prepared, and the surface roughness Ra of any three points on the adherend surface of the concrete plate was measured with a laser microscope "VK-9710" manufactured by KEYENCE CORPORATION. As a result, the surface roughness Ra of each measurement point of the concrete plate was in the range of 23.3 to 88.3 μm (all 100 μm or less).

Next, in the same manner as in the case of the mortar plate, the adhesive strength of the adhesive tapes of Examples 1 to 6 and Comparative Examples 1 to 5 with respect to the concrete plate was measured at a temperature of 23 ° C. and a temperature of 70 ° C.

Finally, after measuring the adhesive strength at both temperatures, the adherend surfaces of the mortar plate and the concrete plate after the adhesive tape was completely peeled off were observed to confirm the presence or absence of adhesive residue.

The above results are shown in Table 1 for mortar plates and Table 2 for concrete plates.

In Tables 1 and 2, "no adhesive residue" means that no adhesive residue was observed on the adherend surface, and "presence" means that no adhesive residue was observed on the adherend surface. It was done.

<Ball tackiness>
A ball made of high carbon chrome bearing steel is described in JIS Z 0237 (2009) by fixing an adhesive tape from which a release PET film has been peeled off to an inclined table having an inclination angle of 30 degrees so that the functional layer faces the upper surface. I rolled it in the same way. At this time, a ball having a diameter of 2/32 inch to 1 inch was used. Then, among the balls that stop on the surface of the functional layer when the ball is rolled, the value of the ball number having the maximum diameter is specified and used as the ball number in this ball tack test.

Here, the ball number is obtained by multiplying the diameter of the ball by 32. That is, the one with a diameter of 1 inch is called a ball number 32, and the one with a diameter of 2/32 inches is called a ball number 2. The larger the ball number, the stronger the tacking force (the force to adhere to the adherend with a light force) of the adhesive tape. When the ball number is smaller than 3, the tackiness becomes considerably small, so that the ball tends to float from the tape edge surface.

The above results are shown in Table 3.

From Table 1 using the mortar plate, it can be seen that the adhesive tapes of Examples 1 to 6 and Comparative Examples 1, 3 and 5 obtained a result satisfying a strong adhesive state of 6 N / 10 mm or more at 23 ° C. adhesive strength. .. Further, the adhesive strength at 70 ° C. after heating in Examples 1 to 6 was reduced to less than 1N / 10 mm, and the adhesive tape could be peeled off without adhesive residue by heating.

On the other hand, the adhesive tapes of Comparative Examples 1 and 5 containing no heat-expandable particles in the functional layer have an adhesive force of 70 ° C. after heating exceeding 1 N / 10 mm, and the adhesive tape has no adhesive residue even when heated. I couldn't peel it off.

Further, the adhesive tape of Comparative Example 2 in which the functional layer contains 40 parts of heat-expandable particles with respect to 100 parts of the tacky resin has an adhesive strength of less than 6 N / 10 mm at 23 ° C. Peeling occurred at the end.

Further, the adhesive tape of Comparative Example 3 having a functional layer thickness of 15 μm has an adhesive force of 70 ° C. after heating exceeding 1 N / 10 mm, and the adhesive tape can be peeled off without adhesive residue even when heated. could not.

Further, the adhesive tape of Comparative Example 4 having a functional layer thickness of 125 μm had an adhesive strength at 23 ° C. of less than 6 N / 10 mm, and peeling occurred at the end of the adhesive tape immediately after bonding. In addition, the adhesive strength at 70 ° C. after heating exceeded 1 N / 10 mm, and the adhesive tape could not be peeled off without adhesive residue even after heating.

Further, from Table 2 using the concrete plate, it can be seen that the same result as the adhesive force to the mortar plate was obtained for the adhesive force to the concrete plate.

The adhesive tape disclosed in the present application can prevent deterioration of cement-based structures by a simple method, and can be widely used as an adhesive tape having excellent handleability, and is particularly useful in the fields of civil engineering and construction.

1 Thermal expansion particles 2 Outer shell 3 Hydrocarbons 10, 20 Adhesive tape 11 Base material 12 Adhesive layer 13 Functional layer 12a Glue residue 14 Release sheet 15 Concrete 16 Cracks 17 External stimulus

Claims (19)

An adhesive tape containing a base material, an adhesive layer, and a functional layer in this order.
The adhesive layer contains an adhesive and
The functional layer contains heat-expandable particles and a tacky resin.
The expansion coefficient when the heat-expandable particles are heated to 60 ° C. or higher is 2 times or more and 150 times or less with respect to the volume of the heat-expandable particles at 23 ° C.
The adhesive force on the adhesive layer side of a cement-based structure having a surface roughness Ra of 100 μm or less is measured in an environment of a temperature of 23 ° C. and a relative humidity of 50% as a 180 ° peeling force measured according to the provisions of JIS Z0237. When measured in an environment of 6 N / 10 mm or more, a temperature of 70 ° C., and a relative humidity of 5% or less, it is 1 N / 10 mm or less.
An adhesive tape having a tack property on the functional layer side of 5 or more as a ball number in a ball tack test defined in JIS Z0237. The adhesive tape according to claim 1, wherein at least one selected from the adhesive layer and the functional layer contains a material that can be heated by an external stimulus. The adhesive tape according to claim 1 or 2, wherein the base material and the adhesive layer are in contact with each other, and the adhesive layer and the functional layer are in contact with each other. The pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer is at least one type of pressure-sensitive adhesive component selected from the group consisting of natural rubber-based pressure-sensitive adhesive components, synthetic rubber-based pressure-sensitive adhesive components, silicone-based pressure-sensitive components, acrylic-based pressure-sensitive components, and polyester-based pressure-sensitive adhesive components. The adhesive tape according to any one of claims 1 to 3. The adhesive tape according to any one of claims 1 to 4, wherein the heat-expandable particles include an outer shell made of a thermoplastic resin and a hydrocarbon having 5 to 12 carbon atoms contained in the outer shell. .. The adhesive tape according to any one of claims 1 to 5, wherein the content of the heat-expandable particles in the functional layer is 1 to 35 parts by mass with respect to 100 parts by mass of the tacky resin. The tacky resin contained in the functional layer is a polyolefin resin, a polyvinyl chloride resin, an acrylic resin, a polyester resin, a fluorine resin, an aramid resin, a natural rubber resin, a synthetic rubber resin, or a silicone resin. The adhesive tape according to any one of claims 1 to 6, which is at least one resin selected from the group consisting of, and a urethane-based resin. The adhesive tape according to any one of claims 1 to 7, wherein the material capable of heating by an external stimulus is a material capable of electromagnetic induction heating or a material capable of microwave heating. The adhesive tape according to claim 8, wherein the material capable of electromagnetic induction heating is a conductor. The adhesive tape according to claim 9, wherein the conductor is made of at least one material selected from the group consisting of a metallic material and a conductive non-metallic material. The metal material includes aluminum, iron, copper, silver, gold, nickel, platinum, zinc, lead and stainless steel, and the conductive non-metal material includes carbon black, carbon fiber and graphene. Item 10. The adhesive tape according to Item 10. The adhesive tape according to claim 8, wherein the material capable of microwave heating is at least one selected from the group consisting of a dielectric, a conductor, and a magnetic material. Claims 8 to 12 wherein the content of the material capable of electromagnetic induction heating or the material capable of microwave heating in the functional layer is 1 to 20 parts by mass with respect to 100 parts by mass of the tacky resin. The adhesive tape according to any one of the items. The claim that the content of the material capable of electromagnetic induction heating or the material capable of microwave heating in the adhesive layer is 1 to 20 parts by mass with respect to 100 parts by mass of the adhesive component contained in the adhesive layer. The adhesive tape according to any one of 8 to 13. The adhesive tape according to any one of claims 1 to 14, wherein the thickness of the adhesive layer is 200 to 5000 μm. The adhesive tape according to any one of claims 1 to 15, wherein the thickness of the functional layer is 20 to 100 μm. Carbon dioxide permeability at 20 ° C. as specified in JIS K7126 is, pressure-sensitive adhesive tape according to any one of claims 1 to 16 is ^{0.5g / (m 2 · 24hr ·} 1atm) below. The step of preparing the adhesive tape according to any one of claims 1 to 17, and
The step of attaching the functional layer side of the adhesive tape to the deteriorated portion of the cement-based structure, and
A process of leaving the cement-based structure to which the adhesive tape is attached in a natural environment for a certain period of time,
After being left to stand, the adhesive tape is heated to 60 ° C. or higher to reduce the adhesive strength of the adhesive tape.
A method of using an adhesive tape, which comprises a step of peeling the adhesive tape having a reduced adhesive strength from the cement-based structure. In the adhesive tape, the total thickness of the adhesive layer and the functional layer is 0.5 times or more the ten-point average roughness Rz specified in JIS B0601 of the cement-based structure. The method of using the adhesive tape according to claim 18.

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