JP6715630B2 - Adhesive composition for reinforcing bar joint, connecting reinforcing bar, structure and method for manufacturing connecting reinforcing bar - Google Patents

Description

The present invention relates to an adhesive composition for a reinforcing bar joint, a connecting reinforcing bar, a structure, and a method for manufacturing a connecting reinforcing bar.

BACKGROUND ART Conventionally, it has been generally practiced that reinforcing bars arranged in beams and columns of a concrete structure are combined and made into one long steel bar. In that case, use a coupler with an injection hole near the center, press-fit an organic grout material such as epoxy resin from the injection hole, fill the butt face of the reinforcing bar and the gap in the coupler, and cure to connect the reinforcing bar. The method of doing (integrating) is performed.

In the conventional epoxy resin-based organic grout material, the epoxy resin does not harden at low temperatures, especially at 5° C. or lower, so it is necessary to take measures such as heating the grout material at the construction site.

In order to solve this problem, for example, in Patent Document 1, (1) a methacrylate-based component, (2) a polymerization initiator, (3 A curable resin composition for a threaded joint of a steel rod has been proposed which contains a polymerization accelerator, (4) an elastomer component and (5) silica powder in a specified amount.

JP, 2003-105044, A

However, in Patent Document 1, the screw joint strength is measured only at room temperature (23° C.) and −10° C. Since the curing of the adhesive is a chemical reaction, the lower the reaction temperature, the lower the reactivity (curability). In Patent Document 1, the strength such as the curability (rapid curability) and the compressive strength for a short period (for example, 7 days) at a temperature lower than -10°C (for example, -20°C) is examined. Absent. Patent Document 1 does not describe the combined use of two kinds of silica powders having different average primary particle diameters.

Further, in recent years, the strength of connection reinforcing bars and the like has been required to be even better than in the past. Therefore, there is a need for an adhesive composition that can exhibit such excellent strength.

Further, in addition to the above-mentioned strength, an adhesive composition that can be used outdoors such as at a construction site is required to have good filling properties in a wide temperature range from low temperatures in winter to high temperatures in summer. For example, when the filling property in a wide temperature range is low, the filling property is good at a low temperature, but the curing of the adhesive composition is too fast at a high temperature such as 40° C., and the adhesive composition is cured during the filling process. , Inferior in workability.

Therefore, the present invention provides an adhesive composition for a reinforcing bar joint, which has fast curing property at low temperature, good filling property in a wide temperature range, and excellent strength (for example, compressive strength). The purpose is to do. Another object of the present invention is to provide a connecting rebar having excellent strength. Still another object of the present invention is to provide a structure having connecting reinforcing bars having excellent strength. Still another object of the present invention is to provide a method for manufacturing a connecting rebar having excellent strength.

The adhesive composition for a reinforcing bar joint according to the present invention,
(A) monofunctional (meth)acrylate,
(B) polyfunctional (meth)acrylate,
(C) thermal radical polymerization initiator,
(D) a polymerization accelerator, and (F) a filler,
The F component is a combination of a filler having an average primary particle diameter of 10 μm or more and 50 μm or less and a filler having an average primary particle diameter of 20 nm or less, and the proportion of the filler having an average primary particle diameter of 10 μm or more and 50 μm or less is 90 mass% or more and 98 mass% or less with respect to the total 100 mass% of the agent, and 0.2 mass part or more and 0.6 mass part or less of the D component with respect to 100 mass parts of the total of the A component and the B component. An adhesive composition for a reinforcing bar joint, which contains the component (E) in an amount of 0 part by mass or more and 15 parts by mass or less based on 100 parts by mass of the total of the components A and B. Since the adhesive composition for a reinforcing bar joint has such a composition, it has fast curing property at low temperature, good filling property in a wide temperature range, and excellent strength (for example, compressive strength). be able to.

In the present invention, (meth)acrylate means one or more selected from the group consisting of acrylate and methacrylate. In the present invention, the (meth)acryloyl group means one or more groups selected from the group consisting of an acryloyl group and a methacryloyl group. In the present invention, monofunctional means having one (meth)acryloyl group. In the present invention, polyfunctional means having two or more (meth)acryloyl groups.

In the present invention, the compressive strength is obtained by the method described in Examples.

In the present invention, the curing of the adhesive composition for reinforcing bar joints is measured by the method described in Examples.

In the present invention, two or more embodiments can be arbitrarily combined.

In one embodiment of the adhesive composition for a reinforcing bar joint according to the present invention, the F component is silica.

In one embodiment of the adhesive composition for a reinforcing bar joint according to the present invention, 100 parts by mass or more and 400 parts by mass or less of the F component is contained with respect to 100 parts by mass of the total of the A component and the B component.

A connecting reinforcing bar according to the present invention is a connecting reinforcing bar manufactured by using the adhesive composition for a reinforcing bar joint. Thereby, the connecting rebar has excellent strength.

A structure according to the present invention is a structure having the above-mentioned connecting reinforcing bar.

The manufacturing method of the connecting rebar according to the present invention,
A step of preparing a coupler for fixing the end portion of the reinforcing bar having an injection hole,
Preparing multiple rebars,
Inserting the rebar one by one from both ends of the coupler,
A step of filling a gap between the reinforcing bars in the coupler with the reinforcing bar joint adhesive composition from the injection hole,
A step of curing the adhesive composition for reinforcing bar joint,
And a method for manufacturing a connected reinforcing bar. This makes it possible to obtain a connecting reinforcing bar having excellent strength.

In one embodiment of the manufacturing method of the connecting reinforcing bar concerning the present invention, the temperature of the process of hardening is -20 °C or more and +40 °C or less. By using the adhesive composition for a reinforcing bar joint, it can be cured at -20°C or higher and +40°C or lower.

According to the present invention, there is provided an adhesive composition for a reinforcing bar joint, which has fast curing property at low temperature, good filling property in a wide temperature range, and excellent strength (for example, compressive strength). Can be provided. According to the present invention, it is possible to provide a connecting reinforcing bar having excellent strength. According to the present invention, it is possible to provide a structure having a connecting reinforcing bar having excellent strength. According to the present invention, it is possible to provide a method for manufacturing a connecting rebar having excellent strength.

Hereinafter, embodiments of the present invention will be described. These descriptions are intended to exemplify the invention and are not intended to limit the invention in any way.

(Adhesive composition for reinforcing bar joint)
The adhesive composition for a reinforcing bar joint according to the present invention,
(A) monofunctional (meth)acrylate,
(B) polyfunctional (meth)acrylate,
(C) thermal radical polymerization initiator,
(D) a polymerization accelerator, and (F) a filler,
The F component is a combination of a filler having an average primary particle diameter of 10 μm or more and 50 μm or less and a filler having an average primary particle diameter of 20 nm or less, and the proportion of the filler having an average primary particle diameter of 10 μm or more and 50 μm or less is 90 mass% or more and 98 mass% or less with respect to the total 100 mass% of the agent, and 0.2 mass part or more and 0.6 mass part or less of the D component with respect to 100 mass parts of the total of the A component and the B component. An adhesive composition for a reinforcing bar joint, which contains the component (E) in an amount of 0 part by mass or more and 15 parts by mass or less based on 100 parts by mass of the total of the components A and B. Since the adhesive composition for a reinforcing bar joint has such a composition, it has fast curing property at low temperature, good filling property in a wide temperature range, and excellent strength (for example, compressive strength). be able to.

<(A) Monofunctional (meth)acrylate>
The component A is a monofunctional (meth)acrylate. The monofunctional (meth)acrylate is not particularly limited and can be appropriately selected and used from known monofunctional (meth)acrylates.

Examples of the component A include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate. , Lauryl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth) Acrylate, isobornyl (meth)acrylate, methoxylated cyclodecatriene (meth)acrylate, methoxylated cyclotriene (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl( (Meth)acrylate, 4-hydroxybutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycidyl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, 3-chloro-2-hydroxypropyl(meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, N,N-diethylaminoethyl(meth)acrylate, t-butylaminoethyl(meth)acrylate, ethoxycarbonylmethyl( (Meth)acrylate, phenol ethylene oxide modified (meth)acrylate, phenol (ethylene oxide 2 mol modified) (meth)acrylate, phenol (ethylene oxide 4 mol modified) (meth)acrylate, paracumylphenol ethylene oxide modified (meth)acrylate, Nonylphenol ethylene oxide modified (meth)acrylate, nonylphenol (ethylene oxide 4 mol modified) (meth)acrylate, nonylphenol (ethylene oxide 8 mol modified) (meth)acrylate, nonylphenol (propylene oxide 2.5 mol modified) acrylate, 2-ethylhexyl Carbitol (meth)acrylate, ethylene oxide modified phthalic acid (meth)acrylate, ethylene oxide modified succinic acid (meth)acrylate, trifluoroethyl (meth)acrylate, ω-carboxy-polycaprolactone mono (meth) Acrylate, monohydroxyethyl (meth)acrylate phthalate, β-(meth)acryloyloxyethyl hydrogen succinate, n-(meth)acryloyloxyalkyl hexahydrophthalimide, 2-(1,2-cyclohexanedicarboximide) Examples thereof include ethyl acrylate.

As the component A, one type may be used alone, or two or more types may be used in combination.

The content of the component A is preferably 60 parts by mass or more and 85 parts by mass or less, and more preferably 70 parts by mass or more and 75 parts by mass or less with respect to 100 parts by mass in total of the components A and B.

<(B) Polyfunctional (meth)acrylate>
Component B is a polyfunctional (meth)acrylate. The polyfunctional (meth)acrylate is not particularly limited and can be appropriately selected and used from known bifunctional, trifunctional, tetrafunctional, pentafunctional and hexafunctional polyfunctional (meth)acrylates.

Examples of the component B include 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexadiol di(meth)acrylate, and 1,9-nonanediol di. (Meth)acrylate, neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, neopentyl glycol modified trimethylolpropane di(meth)acrylate, stearic acid modified pentaerythritol di(meth)acrylate, hexane Bifunctional (meth)acrylates such as diol di(meth)acrylate may be mentioned.

In addition, examples of the B component include bisphenol A type epoxy (meth)acrylate. Examples of the bisphenol A type epoxy (meth)acrylate include ethylene oxide-modified bisphenol A diacrylate, 2,2-bis(4-(methacryloxy-ethoxy)phenyl)propane and 2,2-bis(4-(methacryloxy-ethoxy)phenyl). Propane (2.3 mol of ethylene oxide), 2,2-bis(4-(methacryloxy-ethoxy)phenyl)propane (2.6 mol of ethylene oxide), 2,2-bis(4-(methacryloxy-diethoxy)phenyl)propane ( Ethylene oxide 4 mol), 2,2-bis(4-(methacryloxy-polyethoxy)phenyl)propane (ethylene oxide 10 mol), 2,2-bis(4-(methacryloxy-polyethoxy)phenyl)propane (ethylene oxide 17 mol), 2 ,2-bis(4-(methacryloxy-polyethoxy)phenyl)propane (ethylene oxide 30 mol), 2,2-bis(4-(acryloxy-polyethoxy)phenyl)propane (ethylene oxide 3 mol), 2,2-bis(4 -(Acryloxy-polyethoxy)phenyl)propane (ethylene oxide 10 mol), 2,2-bis(4-(acryloxy-polyethoxy)phenyl)propane (ethylene oxide 20 mol), 2,2-bis(4-(acryloxy-polyethoxy) Phenyl)propane (ethylene oxide 30 mol), 2,2-bis(4-(acryloxy-diethoxy)phenyl)propane (ethylene oxide 4 mol), bisphenol A ethylene oxide adduct diacrylate, bisphenol A propylene oxide adduct diacrylate, Bisphenol A propylene oxide 2 mol adduct methacrylic acid adduct of diglycidyl ether, bisphenol A propylene oxide 2 mol adduct diglycidyl ether acrylic acid adduct, bisphenol A diglycidyl ether methacrylic acid adduct, bisphenol A diglycidyl ether acryl Examples thereof include acid addition products, ethylene oxide-modified bisphenol A dimethacrylate, ethylene oxide 10 mol modified bisphenol A type diacrylate, and bisphenol A polypropoxy diacrylate.

As the B component bisphenol A type epoxy (meth)acrylate, a commercially available product may be used. Examples of such commercially available products include, for example, Viscoat #540 manufactured by Osaka Organic Chemical Industry Co., Ltd., NK ester series manufactured by Shin Nakamura Chemical Co., Ltd. (for example, NK ester BPE-80N, NK ester BPE-). 100, NK ester BPE-200, NK ester BPE-500, NK ester BPE-900, NK ester BPE-1300N, NK ester ABE-300, NK ester A-BPE-10, NK ester A-BPE-20, NK ester A-BPE-30, NK ester A-BPE-4, etc.); Kyoeisha Chemical Co., Ltd. light acrylate series (for example, product name light acrylate BP-4EAL, light acrylate BP-4PA, etc.), epoxy ester series (for example, Epoxy ester 3002M(N), epoxy ester 3002A(N), epoxy ester 3000MK, epoxy ester 3000A, etc.); trade name BPE-4, BPE-10, BPE-20, BPEM-10 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., BPP-4 etc. are mentioned.

The component B can be used alone or in combination of two or more.

The content of the B component is preferably 15 parts by mass or more and 40 parts by mass or less, more preferably 25 parts by mass or more and 30 parts by mass or less, and 25 parts by mass or more 28 with respect to 100 parts by mass in total of the A component and the B component. It is more preferably less than or equal to parts by mass.

<(C) Thermal Radical Polymerization Initiator>
Component C is a thermal radical polymerization initiator. The thermal radical polymerization initiator is not particularly limited and can be appropriately selected and used from known thermal radical polymerization initiators capable of generating radicals by the reaction with the component D.

Examples of the C component include cumene hydroperoxide (α-cumyl hydroperoxide), paramenthane hydroperoxide, tert-butyl hydroperoxide, diisopropylbenzene dihydroperoxide, methyl ethyl ketone peroxide, benzoyl peroxide, tert- Butyl peroxybenzoate, dibenzoyl peroxide, 1,1-bis(tert-butylperoxy)-2-methylcyclohexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexanoate, t -Organic peroxides such as -butyl peroxyacetate, dicumyl peroxide, ethyl-3,3-di-(t-butylperoxy)butyrate; azobisisobutyronitrile, azobiscyclohexanecarbonitrile, azobismethyl Examples thereof include compounds such as azo compounds such as propionitrile and azobismethylbutyronitrile.

The component C is preferably an organic peroxide.

C component can be used individually by 1 type or in combination of 2 or more types.

The content of the C component is preferably 2 parts by mass or more and 6 parts by mass or less, more preferably 2 parts by mass or more and 5 parts by mass or less, and more preferably 3 parts by mass or more 5 with respect to 100 parts by mass in total of the A component and the B component. It is more preferably less than or equal to parts by mass.

<(D) Polymerization accelerator>
Component D is a polymerization accelerator. The polymerization accelerator is not particularly limited as long as it has a function of decomposing the C component by reaction with the C component and generating a radical, and can be appropriately selected and used from known polymerization accelerators.

Examples of the D component include thiourea derivatives such as acetyl-2-thiourea, benzoylthiourea, N,N-diphenylthiourea, N,N-diethylthiourea, N,N-dibutylthiourea and tetramethylthiourea; vanadyl Β-diketone chelates such as acetylacetonate, cobalt acetylacetonate and copper acetylacetonate; metal salts of organic acids such as vanadyl naphthenate, vanadyl stearate, copper naphthenate and cobalt octylate.

The component D can be used alone or in combination of two or more.

The content of the D component is 0.2 parts by mass or more and 0.6 parts by mass or less based on 100 parts by mass of the total of the A component and the B component. By containing the component D in an amount of 0.2 parts by mass or more, fast curability can be achieved even in a low temperature of −20° C. in a short period such as 7 days. If more than 0.6 parts by mass of component D is added, not only the effect of accelerating the hardening is not observed, but also the hardening is too fast at a high temperature, which may cause insufficient filling into the joint. Costs rise and is economically disadvantageous. The content of the D component is preferably 0.3 parts by mass or more and 0.5 parts by mass or less based on 100 parts by mass of the total of the A component and the B component.

<(E) Elastomer>
Component E is an elastomer and is an optional component. The elastomer has the property of reducing the compressive strength of the cured product of the adhesive composition for reinforcing bar joints, but on the contrary has the property of improving brittleness and obtaining a toughened cured product. The elastomer is not particularly limited and can be appropriately selected and used from known elastomers such as rubber.

As the E component, for example, acrylonitrile-butadiene-methacrylic acid copolymer, acrylonitrile-butadiene-methacrylate copolymer, methyl methacrylate-butadiene-styrene copolymer, acrylonitrile-styrene-butadiene copolymer, acrylonitrile-butadiene rubber, Various synthetic rubbers such as linear polyurethane, styrene-butadiene rubber, chloroprene rubber and butadiene rubber; styrene thermoplastic elastomers such as natural rubber and styrene-polybutadiene-styrene synthetic rubber; olefin thermoplastics such as polyethylene-EPDM synthetic rubber Elastomers: urethane-based thermoplastic elastomers such as caprolactone-type, adipate-type, and PTMG-type; polyester-based thermoplastic elastomers such as polybutylene terephthalate-polytetramethylene glycol multiblock polymers; polyamide-based thermoplastics such as nylon-polyol block copolymers Elastomers; 1,2-polybutadiene-based thermoplastic elastomers; PVC-based thermoplastic elastomers; modified products of these.

E component can be used individually by 1 type or in combination of 2 or more types.

The content of the E component is 0 parts by mass or more and 15 parts by mass or less based on 100 parts by mass of the total of the A component and the B component. By adjusting the amount of the E component to 15 parts by mass or less, fast curing at low temperature, good filling property in a wide temperature range, and excellent strength (compressive strength) can be exhibited. The content of the E component is preferably 0 parts by mass or more and 13 parts by mass or less, and more preferably 0 parts by mass or more and 8 parts by mass or less with respect to 100 parts by mass of the total of the A component and the B component.

<(F) Filler>
The F component is a filler. The filler has the effects of increasing the viscosity of the adhesive composition for reinforcing bar joints, improving workability and sagability, and further reducing the apparent curing shrinkage rate of the adhesive composition for reinforcing bar joints. The filler is not particularly limited and may be used by appropriately selecting from known fillers, and may be used alone or in combination of two or more.

Examples of the F component include silica, calcium carbonate, clay, kaolin, talc, titanium oxide, hydrotalcite, mica, carbon black and the like. In one embodiment, the F component is silica. The F component may be used alone or in combination of two or more.

The type of silica is not particularly limited and can be appropriately selected and used according to the application, desired performance and the like. Examples thereof include crystalline silica powder, fused silica powder, spherical silica powder, fumed silica and the like.

The F component is a combination of a filler having an average primary particle diameter of 10 μm or more and 50 μm or less and a filler having an average primary particle diameter of 20 nm or less, and the proportion of the filler having an average primary particle diameter of 10 μm or more and 50 μm or less is 90 mass% or more and 98 mass% or less with respect to 100 mass% of total agents. A filler having an average primary particle diameter of 10 μm or more and 50 μm or less can be highly filled in a composition consisting of A component, B component, C component, D component and E component, and can reduce the curing shrinkage rate of the entire composition. Since the filler having a primary particle size of 20 nm (200Å) or less is an ultrafine particle, a small amount of the filler may increase the viscosity of the composition comprising the A component, B component, C component, D component, E component and F component. Therefore, it is possible to improve workability by suppressing dropping. The filler having an average primary particle diameter of 20 nm or less preferably has an average primary particle diameter of 1 nm or more, and more preferably 5 nm or more.

The average primary particle diameter is measured by SEM (scanning electron microscope) or TEM (transmission electron microscope).

The content of the F component is preferably 100 parts by mass or more and 400 parts by mass or less, and more preferably 280 parts by mass or more and 320 parts by mass or less with respect to 100 parts by mass of the total of the A component and the B component.

The adhesive composition is a coloring agent such as dyes and pigments, a plasticizer, a rust preventive agent, a toughening agent, and a weather resistance, in addition to the above-mentioned components, as long as the object of the present invention is not impaired. Agents; Solvents; Dispersants; Surfactants and mineral oils, and other known additives used in adhesive compositions may be included.

The adhesive composition can be used for various purposes. Examples include connecting reinforcing bars and wires, connecting steel structures where welding cannot be used, and the like. The adhesive composition has fast curing property at low temperature, good filling property in a wide temperature range, and excellent strength (for example, compressive strength). It can be preferably used for material applications).

The adhesive composition may include the above-mentioned components (component E is an optional component), and the form is not particularly limited, and a known form can be appropriately selected. In one embodiment, the adhesive composition is a one-pack type (one-pack type) adhesive composition, and in another embodiment, a two-pack type (two-pack type) containing a first agent and a second agent. It is an adhesive composition. In the case of a two-component adhesive composition, either the first agent or the second agent contains the C component, and the other contains the D component.

(Connected rebar)
A connecting reinforcing bar according to the present invention is a connecting reinforcing bar manufactured by using the adhesive composition for a reinforcing bar joint. Thereby, the connecting rebar has excellent strength. In one embodiment, coupling reinforcing bars according to the present invention, compressive strength at -20 ° C. is at 70N / mm ² or more, in another embodiment, is a compression strength of at -20 ° C. is 90 N / mm ² or more ..

(Method of manufacturing connected rebar)
The manufacturing method of the connecting rebar according to the present invention,
A step of preparing a coupler for fixing the end portion of the reinforcing bar having an injection hole,
Preparing multiple rebars,
Inserting the rebar one by one from both ends of the coupler,
A step of filling a gap between the reinforcing bars in the coupler with the reinforcing bar joint adhesive composition from the injection hole,
A step of curing the adhesive composition for reinforcing bar joint,
And a method for manufacturing a connected reinforcing bar. This makes it possible to obtain a connecting reinforcing bar having excellent strength. Hereinafter, each step will be described as an example.

<Coupler preparation process>
In the coupler preparation step, a coupler for fixing the end portion of the reinforcing bar is prepared. The coupler has an injection hole of the adhesive composition for a reinforcing bar joint. Any coupler may be used as long as it is for fixing the end portion of the reinforcing bar, and a known mechanical coupler can be appropriately selected and used. Examples of the couplers for mechanical joints include couplers for threaded joints and couplers for tapping.

A commercial item can be used for a coupler. For example, a screw name (registered trademark), a high-ten coupler, and the like manufactured by JFE Steel Co., Ltd. may be used.

<Reinforcing bar preparation process>
In the reinforcing bar preparation step, a plurality of reinforcing bars are prepared. The reinforcing bar is not particularly limited, and known reinforcing bars (steel bars for reinforced concrete) can be appropriately selected and used. Examples of the reinforcing bar include deformed reinforcing bars such as JIS G 3112 and round steel. As the deformed bar, for example, a threaded bar and the like can be mentioned. The reinforcing bars of the plurality of reinforcing bars to be prepared may have the same composition, shape, dimensions, or the like, or may have different compositions.

<Insertion process>
In the insertion step, one rebar is inserted from each end of the coupler. The method for inserting the reinforcing bars (joining the coupler) is not particularly limited and can be appropriately selected. For example, in the case of a joint having the same diameter, a coupler may be set on one rebar and the other rebar may be inserted from the other end so that the ends of both rebars are positioned in the coupler. Also, for example, in the case of different diameter joints, set the coupler on the small diameter side reinforcing bar, open the butting interval, insert it while rotating the coupler on the large diameter side reinforcing bar, and insert both the reinforcing bars inside the coupler. The end may be located.

<Filling process>
In the filling step, the abutting surfaces and gaps between the reinforcing bars in the coupler are filled with the adhesive composition for reinforcing bar joint through the injection holes of the coupler. The filling method is not particularly limited, and a known method can be appropriately selected and used. For example, a method using a manual injector or an electric injector using a compressor and a sealant gun can be used. The filling amount may be appropriately adjusted according to the size of the coupler and the like, and is not particularly limited. For example, the filling amount may be such that the adhesive composition overflows from both ends of the coupler.

<Curing process>
In the curing step, the reinforcing bar joint adhesive composition filled in the coupler is cured. In the curing step, it is preferable to leave the coupler and the reinforcing bar still.

In one embodiment of the manufacturing method of the connection reinforcing bar concerning the present invention, the temperature of a hardening process is -20 °C or more and +40 °C or less. By using the adhesive composition for a reinforcing bar joint, it can be cured at -20°C or higher and +40°C or lower. In another embodiment, the adhesive composition for a reinforcing bar joint can be cured at −15° C. or higher and 40° C. or lower for 7 days (in other words, before 8 days have passed) to exhibit excellent compressive strength.

<Heating process>
The method for manufacturing a connected reinforcing bar according to the present invention may further include a step of heating the reinforcing bar joint adhesive composition before or at the same time as the filling step. As a result, the handleability and filling property of the adhesive composition for a reinforcing bar joint are further improved when the temperature of the construction environment such as winter or cold regions is low. The heating method is not particularly limited and may be appropriately selected. For example, a method of warming the adhesive composition with warm water of about 40° C. and the like can be mentioned.

(Structure)
A structure according to the present invention is a structure having the above-mentioned connecting reinforcing bar. This connecting rebar has excellent strength. The type of structure is not particularly limited, and it can be applied to a known structure having a reinforcing bar. In one embodiment, the structure is a concrete structure.

Hereinafter, the present invention will be described in more detail with reference to Examples, but these Examples are intended to illustrate the present invention and do not limit the present invention in any way. Unless otherwise specified, the blending amount means parts by mass.

Details of the materials used in the examples are as follows.
Monofunctional methacrylate 1, A component 1: Methyl methacrylate Monofunctional methacrylate 2, A component 2: 2-Hydroxyethyl methacrylate polyfunctional (bifunctional) methacrylate, B component: 2,2-bis(4-(methacryloxy-ethoxy)phenyl ) Propane, trade name BPE-100 manufactured by Shin Nakamura Chemical Co., Ltd.
Thermal radical polymerization initiator, C component: cumene hydroperoxide, trade name Park Mill (registered trademark) H-80 manufactured by NOF CORPORATION
Polymerization accelerator, D component: vanadyl acetylacetonate, elastomer manufactured by Shinko Kagaku Kogyo Co., Ltd. E component: Acrylonitrile-butadiene rubber (commercially available product) and a mixture of methylmethacrylate-butadiene-styrene copolymer (commercially available product) silica powder, F component: Mixture consisting of 96.5% by mass of silica powder having an average primary particle diameter of 30 μm (commercially available product) and 3.5% by mass of silica powder having an average primary particle diameter of 12 nm (commercially available product) Reinforcing bar: Threaded rebar, JFE bar stock Company name Nejibar (registered trademark) trademark registration No. 5608212
Coupler: mechanical joint, trade name of screw coupler (registered trademark) No. 5707952 of JFE Steel Co., Ltd.

(Examples and comparative examples)
With the composition shown in Table 1, adhesive compositions for reinforcing bar joints of Examples and Comparative Examples were prepared.

Manufacture of Reinforcing Bar Joint At -20°C, the reinforcing bar is inserted into both ends of the coupler, and the adhesive composition for reinforcing bar joint prepared from the injection hole of the coupler is filled and left to stand to give an adhesive composition for reinforcing bar joint. It hardened and the connection reinforcement was obtained. At −20° C., the number of days elapsed until hardening, the compressive strength after 7 days, and the number of days at which a compressive strength of 70 N/mm ² was developed were measured for each connected rebar as shown below. Further, the workability and filling state of the adhesive composition for reinforcing bar joints of each example and comparative example were evaluated. The workability and filling state at 40°C were also evaluated. The results of these measurements are also shown in Table 1.

(Cure days)
It was measured at -20°C. The adhesive composition for reinforcing bar joints is cured according to the test method specified in JIS A 6024-2015 “Epoxy resin for building repair and building reinforcement” 5.31, “Working time” When the temperature in the temperature-time curve of 1 was maximized, it was determined that the curing was performed, and the time when the temperature was maximized was defined as the number of curing days (curing time).

(Compressive strength)
It was measured at -20°C. The compressive strength of the cured adhesive composition for reinforcing bar joints was a value measured by the test method specified in JIS K 6911-1995 "General Test Method for Thermosetting Plastics" 5.19 "Compressive Strength". The specific test was performed by the following procedure. (1) A silicone rubber mold for producing an adhesive composition and a compression test piece (12.7 mm×12.7 mm×25.4 mm) is placed in a predetermined temperature environment (in a thermostatic chamber or thermostatic chamber) for 24 hours. Let stand for more than an hour. (2) The mold was filled with the adhesive in a predetermined temperature environment, and cured and cured in a predetermined temperature environment for a predetermined number of days. (3) After curing and curing for a predetermined number of days, the cured product (test piece) of the adhesive composition was removed from the mold, and the dimensions of the three test pieces were measured with a caliper. (4) A test piece was set in a tensile compression tester equipped with a constant temperature bath set to the same environmental temperature as in (1) to (3) such that the surface of 12.7 mm x 12.7 mm became the loading surface. (5) Test speed 1.0 mm. Loading was performed at min and the maximum load (p) was measured. (6) The compressive strength (σc) was determined by σc=p/area of the loading surface measured with calipers.

As shown in Table 1, in Comparative Example 1 in which the amount of the D component was small, the curing time at −20° C. and the time until the predetermined compressive strength was exhibited were long, resulting in low rapid curability. In addition, in Comparative Example 1, the compressive strength at −20° C. for 7 days was also low. Moreover, in Comparative Example 2 in which the amount of the D component was large, curing at 40° C. was too fast, resulting in poor filling properties. In Comparative Example 3 in which the amount of the E component was large, the viscosity at -20°C was too high and the filling property was poor. On the other hand, in Examples 1 to 3, good results were obtained in terms of fast curing property, filling property and compressive strength.

According to the present invention, there is provided an adhesive composition for a reinforcing bar joint, which has fast curing property at low temperature, good filling property in a wide temperature range, and excellent strength (for example, compressive strength). Can be provided. According to the present invention, it is possible to provide a connecting reinforcing bar having excellent strength. According to the present invention, it is possible to provide a structure having a connecting reinforcing bar having excellent strength. According to the present invention, it is possible to provide a method for manufacturing a connecting rebar having excellent strength.

Claims (7)

(A) monofunctional (meth)acrylate,
(B) polyfunctional (meth)acrylate,
(C) thermal radical polymerization initiator,
(D) a polymerization accelerator, and (F) a filler,
The component F is a combination of a filler having an average primary particle diameter of 10 μm or more and 50 μm or less and a filler having an average primary particle diameter of 1 nm or more and 20 nm or less, and the proportion of the filler having an average primary particle diameter of 10 μm or more and 50 μm or less is 90 mass% or more and 98 mass% or less with respect to 100 mass% of the total filler, and 0.2 mass part or more and 0.6 mass part of the D component to 100 mass parts of the total of the A component and the B component. Parts or less, and the content of the (E) elastomer is 0 parts by mass or more and 15 parts by mass or less with respect to a total of 100 parts by mass of the A component and the B component, and an adhesive composition for a reinforcing bar joint. The adhesive composition for a reinforcing bar joint according to claim 1, wherein the F component is silica. The adhesive composition for reinforcing bar joints according to claim 1 or 2, which contains 100 parts by mass or more and 400 parts by mass or less of the F component with respect to 100 parts by mass in total of the A component and the B component. A connecting rebar manufactured using the adhesive composition for a reinforcing bar joint according to claim 1. A structure having the connecting reinforcing bar according to claim 4. A step of preparing a coupler for fixing the end portion of the reinforcing bar having an injection hole,
Preparing multiple rebars,
Inserting the rebar one by one from both ends of the coupler,
Filling the gap between the reinforcing bars in the coupler with the reinforcing bar joint adhesive composition according to any one of claims 1 to 3 from the injection hole,
A step of curing the adhesive composition for reinforcing bar joint,
And a method for manufacturing a connected reinforcing bar. The method for producing a connected reinforcing bar according to claim 6, wherein the temperature of the curing step is -20°C or higher and +40°C or lower.