Reinforcements and structures

Abstract

To provide a reinforcement material and a reinforcement structure capable of improving a reinforcement performance.SOLUTION: A reinforcement material includes a resin layer and a constraint layer. The resin layer contains a resin component and a gas generating agent, and serves as a reinforcement layer to reinforce a reinforcement target. The constraint layer is arranged over the resin layer. The reinforcement layer contains a matrix resin being a cured product of the resin component, and a plurality of air bubbles generated by foaming of the gas generating agent. In a cross section of the reinforcement layer, a ratio of a total area of the plurality of air bubbles is 83% or more. An elastic modulus of the matrix resin of the reinforcement layer is 1.4 GPa or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to reinforcement materials and reinforcement structures. [Background technology]

[0002] Conventionally, a reinforcing material (reinforcing sheet) comprising a constraining layer and a reinforcing layer has been known. The reinforcing layer contains at least a styrene-butadiene rubber, an epoxy resin, and a foaming agent (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-41210 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for further improvement in the reinforcing performance of the reinforcing material described in the above-mentioned Patent Document 1.

[0005] Therefore, the present invention provides a reinforcing material and a reinforcing structure that can improve reinforcing performance. [Means for solving the problem]

[0006] The present invention [1] is a reinforcing material for reinforcing an object to be reinforced, comprising: a resin layer containing a resin component and a foaming agent, which serves as a reinforcing layer reinforcing the object to be reinforced; and a constraining layer disposed on the resin layer, wherein the reinforcing layer contains a matrix resin formed by hardening the resin component and a plurality of bubbles generated by foaming of the foaming agent, the proportion of the total area of the plurality of bubbles in the cross section of the reinforcing layer being 83% or more, and the modulus of elasticity of the matrix resin of the reinforcing layer being 1.4 GPa or more.

[0007] The present invention [2] includes the reinforcing material of the above [1], wherein the resin component contains a thermosetting resin and rubber, and the proportion of the thermosetting resin is more than 100 parts by mass per 100 parts by mass of the rubber.

[0008] The present invention [3] includes the reinforcing material of the above [2], wherein the thermosetting resin contains a flexible epoxy resin and an epoxy resin other than the flexible epoxy resin, and the proportion of the flexible epoxy resin in the thermosetting resin is 10 mass% or more and less than 50 mass%.

[0009] The present invention [4] includes the reinforcing material according to the above [3], wherein the rubber contains acrylonitrile-butadiene rubber, and the proportion of the acrylonitrile-butadiene rubber is 60 parts by mass or more per 100 parts by mass of the flexible epoxy resin.

[0010] The present invention [5] includes a reinforcement structure comprising an object to be reinforced and a reinforcement member having the reinforcing layer and the constraining layer described in [1] above. [Effects of the Invention]

[0011] According to the reinforcing material and reinforcing structure of the present invention, it is possible to improve the reinforcing performance. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of a reinforcing material according to one embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram for explaining a reinforcing method for reinforcing an object to be reinforced with the reinforcing material shown in FIG. 1, where FIG. 2A shows an attachment process for attaching the reinforcing material to the object to be reinforced, and FIG. 2B shows a curing process for foaming and curing the object to which the reinforcing material has been attached. [Figure 3] FIG. 3 is an enlarged view of the cross section of the reinforcing layer shown in FIG. 2B. DETAILED DESCRIPTION OF THE INVENTION

[0013] 1. Reinforcement material 1 The reinforcing material 1 shown in FIG. 1 is a member for reinforcing a reinforcement object P (see FIG. 2B). Examples of the reinforcement object P include metal panels such as aluminum plates, stainless steel plates, iron plates, copper plates, zinc plates, and brass plates. Metal panels can be used in transportation equipment such as automobiles, railway vehicles, ships, and airplanes, as well as in buildings. Preferably, the reinforcing material 1 is a reinforcing sheet. The reinforcing material 1 includes a resin layer 2 and a constraining layer 3. The reinforcing material 1 includes a release sheet 4 as needed.

[0014] (1) Resin layer 2 The resin layer 2 has a predetermined thickness. In the thickness direction of the resin layer 2, the resin layer 2 has a first surface S1 and a second surface S2.

[0015] The resin layer 2 has a thickness of, for example, 0.1 mm or more, preferably 0.2 mm or more, and for example, 10 mm or less, preferably 5 mm or less.

[0016] With the reinforcing material 1 attached to the reinforcement object P, the resin layer 2 foams and hardens, thereby becoming a reinforcing layer 5 (see FIG. 2B). The reinforcing layer 5 will be described later. The resin layer 2 contains a resin component and a foaming agent. The resin layer 2 may also contain a vulcanizing agent, a vulcanization accelerator, a thermosetting resin curing agent, and other additives as necessary.

[0017] (1-1) Resin component The resin component preferably contains a thermosetting resin and a rubber, and optionally a tackifier.

[0018] The viscosity of the resin component at the decomposition temperature of the foaming agent is, for example, 500 Pa·s or more, preferably 1000 Pa·s or more, and for example, 4000 Pa·s or less, preferably 3500 Pa·s or less. The decomposition temperature of the foaming agent will be described later.

[0019] (1-1-1) Thermosetting resin The thermosetting resin preferably contains a flexible epoxy resin and an epoxy resin other than the flexible epoxy resin. More preferably, the thermosetting resin consists only of a flexible epoxy resin and an epoxy resin other than the flexible epoxy resin. In the following description, the epoxy resin other than the flexible epoxy resin will be referred to as the other epoxy resin.

[0020] The flexible epoxy resin has higher flexibility than bisphenol A epoxy resin. Preferably, the flexible epoxy resin has higher flexibility after curing than aromatic epoxy resins described below. More preferably, the flexible epoxy resin has higher flexibility after curing than other epoxy resins described below.

[0021] Flexible epoxy resins do not contain cyclic structures in their main chains or contain fewer cyclic structures than other epoxy resins described below. Examples of cyclic structures include aromatic rings, aliphatic hydrocarbon rings, and nitrogen-containing rings. Preferably, flexible epoxy resins have a flexible component in their main chains. Examples of the flexible component include long-chain aliphatic hydrocarbon components, rubber components, and polyol components. Examples of the long-chain aliphatic hydrocarbon component include alkylene groups derived from dimer acids of long-chain unsaturated fatty acids. Examples of long-chain unsaturated fatty acids include unsaturated fatty acids with 12 or more carbon atoms. Examples of unsaturated fatty acids with 12 or more carbon atoms include linoleic acid.

[0022] The epoxy equivalent of the flexible epoxy resin is, for example, 220 g / eq or more, preferably 300 g / eq or more, and more preferably 500 g / eq or more. When the epoxy equivalent is equal to or more than the above lower limit, the flexibility of the reinforcing member 11 (see FIG. 2B) can be improved. The reinforcing member 11 will be described later.

[0023] The epoxy equivalent of the flexible epoxy resin is, for example, 2000 g / eq or less, preferably 1200 g / eq or less, more preferably 1000 g / eq or less, and more preferably 800 g / eq or less. When the epoxy equivalent is equal to or less than the upper limit, the reinforcing performance of the reinforcing member 11 can be prevented from being excessively reduced.

[0024] In this embodiment, the reinforcing performance of the reinforcing member 11 is evaluated by the 1 mm bending strength, which is measured by the method described in the examples below.

[0025] Flexible epoxy resins include, for example, aliphatic-modified epoxy resins, ε-caprolactone-modified epoxy resins, thiol-based epoxy resins, rubber-modified epoxy resins, dimer acid-modified epoxy resins, urethane-modified epoxy resins, polyol-modified epoxy resins, and amine-modified epoxy resins. Rubber-modified epoxy resins include, for example, butadiene-based epoxy resins. Butadiene-based epoxy resins include, for example, acrylonitrile-butadiene rubber-modified epoxy resins, carboxyl-terminated acrylonitrile-butadiene rubber-modified epoxy resins, and amino-terminated acrylonitrile-butadiene rubber-modified epoxy resins.

[0026] The flexible epoxy resin is preferably an aliphatic-modified epoxy resin, a rubber-modified epoxy resin, or a dimer acid-modified epoxy resin, more preferably a dimer acid-modified epoxy resin, from the viewpoints of compatibility with rubber and adhesiveness of the resin layer 2. The resin layer 2 may contain multiple types of flexible epoxy resins.

[0027] Commercially available flexible epoxy resins include the jER (registered trademark) series (manufactured by Mitsubishi Chemical Corporation) and the YD series (manufactured by Nippon Steel Chemical & Materials Co., Ltd.). Examples of flexible epoxy resins in the jER series include jER871, jER872, and jER872X75. Examples of flexible epoxy resins in the YD series include YD-172.

[0028] Other epoxy resins include, for example, aromatic epoxy resins, alicyclic epoxy resins, and nitrogen-containing ring epoxy resins.

[0029] Examples of aromatic epoxy resins include bisphenol-type epoxy resins, novolac-type epoxy resins, naphthalene-type epoxy resins, and biphenyl-type epoxy resins.

[0030] Examples of bisphenol type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and bisphenol S type epoxy resins.

[0031] Examples of novolac epoxy resins include phenol novolac epoxy resins and cresol novolac epoxy resins.

[0032] Examples of alicyclic epoxy resins include dicyclocyclic epoxy resins and hydrogenated bisphenol A epoxy resins.

[0033] Examples of nitrogen-containing ring epoxy resins include triglycidyl isocyanurate, hydantoin epoxy resin, and triepoxypropyl isocyanurate resin.

[0034] The epoxy equivalent weight of the other epoxy resin is smaller than that of the flexible epoxy resin, for example, less than 220 g / eq, preferably 200 g / eq or less, and for example, 150 g / eq or more, preferably 160 g / eq or more.

[0035] The proportion of the thermosetting resin in the resin layer 2 is, for example, 10 mass % or more, or preferably 15 mass % or more, and for example, 50 mass % or less, or preferably 30 mass % or less.

[0036] The proportion of the thermosetting resin in the resin component is, for example, 30 mass % or more, preferably 40 mass % or more, and for example, 80 mass % or less, preferably 60 mass % or less.

[0037] The ratio of the thermosetting resin to 100 parts by mass of the rubber is, for example, more than 100 parts by mass, preferably 150 parts by mass or more. When the ratio of the thermosetting resin to the rubber is equal to or greater than the above lower limit, the reinforcing performance of the reinforcing material 1 can be improved.

[0038] The ratio of the thermosetting resin relative to 100 parts by mass of the rubber is, for example, 300 parts by mass or less, or preferably 200 parts by mass or less. When the ratio of the thermosetting resin to the rubber is not more than the above upper limit, the reinforcing performance of the reinforcing material 1 can be improved.

[0039] The proportion of the flexible epoxy resin in the thermosetting resin is, for example, 10% by mass or more, preferably 20% by mass or more, and for example, less than 50% by mass, preferably 45% by mass or less, more preferably 40% by mass or less. When the proportion of the flexible epoxy resin in the thermosetting resin is equal to or more than the above lower limit and less than the above upper limit, the reinforcing performance of the reinforcing material 1 can be further improved.

[0040] (1-1-2) Rubber Examples of rubber include diene rubbers, such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), isoprene rubber, and butadiene rubber.

[0041] The rubber preferably includes styrene-butadiene rubber and acrylonitrile-butadiene rubber. The rubber preferably contains acrylonitrile-butadiene rubber. The rubber more preferably contains styrene-butadiene rubber and acrylonitrile-butadiene rubber.

[0042] The proportion of the rubber in the resin layer 2 is, for example, 3 mass % or more, or preferably 8 mass % or more, and for example, 40 mass % or less, or preferably 20 mass % or less.

[0043] The proportion of the rubber in the resin component is, for example, 20 mass % or more, or preferably 25 mass % or more, and for example, 40 mass % or less, or preferably 35 mass % or less.

[0044] When the thermosetting resin contains a flexible epoxy resin and the rubber contains acrylonitrile-butadiene rubber, the ratio of the acrylonitrile-butadiene rubber to 100 parts by mass of the flexible epoxy resin is, for example, 60 parts by mass or more, preferably 100 parts by mass or more. When the ratio of the acrylonitrile-butadiene rubber to the flexible epoxy resin is equal to or more than the above lower limit, the reinforcing performance of the reinforcing material 1 can be improved.

[0045] The ratio of the acrylonitrile-butadiene rubber to 100 parts by mass of the flexible epoxy resin is, for example, 150 parts by mass or less, preferably 130 parts by mass or less. When the ratio of the acrylonitrile-butadiene rubber to the flexible epoxy resin is not more than the above upper limit, the reinforcing performance of the reinforcing material 1 can be improved.

[0046] When the rubber contains styrene-butadiene rubber and acrylonitrile-butadiene rubber, the ratio of the acrylonitrile-butadiene rubber relative to 100 parts by mass of the styrene-butadiene rubber is, for example, 40 parts by mass or more, preferably 60 parts by mass or more, and more preferably 75 parts by mass or more. When the ratio of the acrylonitrile-butadiene rubber to the styrene-butadiene rubber is equal to or more than the above lower limit, the reinforcing performance of the reinforcing material 1 can be improved.

[0047] The ratio of the acrylonitrile-butadiene rubber to 100 parts by mass of the styrene-butadiene rubber is, for example, less than 100 parts by mass, preferably 80 parts by mass or less. When the ratio of the acrylonitrile-butadiene rubber to the styrene-butadiene rubber is equal to or less than the upper limit, the reinforcing performance of the reinforcing material 1 can be improved.

[0048] (1-1-3) Tackifying resin The tackifying resin imparts tackiness to the resin layer 2 .

[0049] Tackifying resins are classified into, for example, natural resin-based tackifying resins and synthetic resin-based tackifying resins.

[0050] Examples of natural resin-based tackifying resins include rosin-based resins, aromatic modified terpene resins, and terpene-based resins. Examples of rosin-based resins include rosin esters. Examples of terpene-based resins include terpene phenol resins.

[0051] Examples of synthetic resin-based tackifying resins include aliphatic petroleum resins, aromatic petroleum resins, and aliphatic-aromatic copolymer petroleum resins. In the following description, aliphatic petroleum resins will be referred to as C5 petroleum resins, aromatic petroleum resins will be referred to as C9 petroleum resins, and aliphatic-aromatic copolymer petroleum resins will be referred to as C5 / C9 petroleum resins.

[0052] C5 petroleum resins mainly contain structural units derived from aliphatic hydrocarbons having 5 carbon atoms. Examples of aliphatic hydrocarbons having 5 carbon atoms include isoprene and piperylene. C5 petroleum resins are produced by polymerizing a mixture of aliphatic hydrocarbons having 5 carbon atoms that are by-produced by the thermal cracking of naphtha. In the following description, the mixture of aliphatic hydrocarbons having 5 carbon atoms that are by-produced by the thermal cracking of naphtha will be referred to as a C5 fraction.

[0053] C9 petroleum resins mainly contain structural units derived from aromatic hydrocarbons having 9 carbon atoms. Examples of aromatic hydrocarbons having 9 carbon atoms include styrene, vinyltoluene, and indene. C9 petroleum resins are produced by polymerizing a mixture of aromatic hydrocarbons having 9 carbon atoms produced as a by-product of the thermal cracking of naphtha. In the following description, the mixture of aromatic hydrocarbons having 9 carbon atoms produced as a by-product of the thermal cracking of naphtha will be referred to as a C9 fraction.

[0054] C5 / C9 petroleum resins mainly contain structural units derived from aliphatic hydrocarbons having 5 carbon atoms and structural units derived from aromatic hydrocarbons having 9 carbon atoms. C5 / C9 petroleum resins are produced by polymerizing a C5 fraction and a C9 fraction.

[0055] As the tackifying resin, preferably, a synthetic resin-based tackifying resin is used, and more preferably, a C5 / C9 petroleum resin is used.

[0056] The proportion of the tackifier resin in the resin layer 2 is, for example, 1 mass % or more, preferably 5 mass % or more, and for example, 15 mass % or less, preferably 10 mass % or less.

[0057] The proportion of the tackifier resin in the resin component is, for example, 10 mass % or more, preferably 15 mass % or more, and for example, 30 mass % or less, preferably 25 mass % or less.

[0058] The proportion of the tackifier resin relative to 100 parts by mass of the thermosetting resin is, for example, 20 parts by mass or more, preferably 40 parts by mass or more, and for example, 70 parts by mass or less, preferably 60 parts by mass or less.

[0059] The proportion of the tackifier resin relative to 100 parts by mass of rubber is, for example, 50 parts by mass or more, preferably 70 parts by mass or more, and for example, 150 parts by mass or less, preferably 100 parts by mass or less.

[0060] (1-2) Foaming agent The foaming agent foams when heated. When the resin layer 2 contains a foaming agent, the thickness of the reinforcing layer 5 (see FIG. 2B) can be increased, thereby improving the strength of the reinforcing member 11 (see FIG. 2B).

[0061] Foaming agents are classified into, for example, inorganic foaming agents and organic foaming agents.

[0062] Examples of inorganic foaming agents include ammonium carbonate (decomposition temperature: 58°C), ammonium hydrogen carbonate (decomposition temperature: 35°C to 60°C), sodium hydrogen carbonate (decomposition temperature: 140°C to 170°C), ammonium nitrite (decomposition temperature: 210°C), and azides.

[0063] Examples of organic blowing agents include N-nitroso compounds, azo compounds, fluorinated alkanes, hydrazine compounds, semicarbazide compounds, and triazole compounds. Examples of N-nitroso compounds include N,N'-dinitrosopentamethylenetetramine (decomposition temperature: 205°C). Examples of azo compounds include azobisisobutyronitrile (decomposition temperature: approximately 50°C). Examples of hydrazine compounds include 4,4'-oxybis(benzenesulfonylhydrazide) (decomposition temperature: 155°C to 165°C). Examples of semicarbazide compounds include p-toluylenesulfonylsemicarbazide. Examples of triazole compounds include 5-morpholyl-1,2,3,4-thiatriazole.

[0064] The decomposition temperature of the foaming agent is preferably 80°C or higher, more preferably 100°C or higher, and preferably 300°C or lower, more preferably 200°C or lower.

[0065] As the blowing agent, preferably, an organic blowing agent is used, more preferably, a hydrazine compound is used, and more preferably, 4,4'-oxybis(benzenesulfonylhydrazide) (OBSH) is used.

[0066] The content of the foaming agent in the resin layer 2 is, for example, 0.1 mass % or more, or preferably 0.5 mass % or more, and for example, 2 mass % or less, or preferably 1 mass % or less.

[0067] The proportion of the foaming agent relative to 100 parts by mass of the resin component is, for example, 1 part by mass or more, preferably 1.5 parts by mass or more, and for example, 3 parts by mass or less, preferably 2 parts by mass or less.

[0068] (1-3) Vulcanizing agent The vulcanizing agent crosslinks (vulcanizes) the diene rubber when heated.

[0069] Examples of the vulcanizing agent include sulfur, sulfur compounds, and organic peroxides. Preferably, the vulcanizing agent is sulfur.

[0070] The mixing ratio of the vulcanizing agent relative to 100 parts by mass of diene rubber is, for example, 2 parts by mass or more, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, more preferably 40 parts by mass or more, and for example, 80 parts by mass or less, preferably 70 parts by mass or less, more preferably 60 parts by mass or less.

[0071] (1-4) Vulcanization accelerator The vulcanization accelerator accelerates vulcanization by the vulcanizing agent.

[0072] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators, thiourea-based vulcanization accelerators, thiuram-based vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, guanidine-based vulcanization accelerators, aldehyde-ammonia-based vulcanization accelerators, and sulfenamide-based vulcanization accelerators. A preferred example of the vulcanization accelerator is a thiazole-based vulcanization accelerator.

[0073] The mixing ratio of the vulcanization accelerator relative to 100 parts by mass of the vulcanizing agent is, for example, 10 parts by mass or more, or preferably 30 parts by mass or more, and for example, 100 parts by mass or less, or preferably 70 parts by mass or less.

[0074] (1-5) Thermosetting resin curing agent The thermosetting resin curing agent accelerates the curing of the thermosetting resin.

[0075] Thermosetting resin curing agents include, for example, cyanamides, amines, acid anhydrides, amides, hydrazides, imidazoles, and imidazolines.

[0076] An example of the cyanamide is dicyandiamide.

[0077] Examples of amines include ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine, amine adducts thereof, metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0078] Examples of acid anhydrides include phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, dodecenylsuccinic anhydride, dichlorosuccinic anhydride, benzophenonetetracarboxylic anhydride, and chlorendic anhydride.

[0079] The amide may, for example, be a polyamide.

[0080] Hydrazides include, for example, dihydrazides.

[0081] Imidazoles include, for example, methylimidazole, 2-ethyl-4-methylimidazole, ethylimidazole, isopropylimidazole, 2,4-dimethylimidazole, phenylimidazole, undecylimidazole, heptadecylimidazole, and 2-phenyl-4-methylimidazole.

[0082] Examples of imidazolines include methylimidazoline, 2-ethyl-4-methylimidazoline, ethylimidazoline, isopropylimidazoline, 2,4-dimethylimidazoline, phenylimidazoline, undecyliimidazoline, heptadecylimidazoline, and 2-phenyl-4-methylimidazoline.

[0083] The proportion of the thermosetting resin curing agent relative to 100 parts by mass of the thermosetting resin is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and for example, 10 parts by mass or less, preferably 7 parts by mass or less.

[0084] (1-6) Other additives The resin layer 2 may further contain other additives, such as fillers and pigments.

[0085] Fillers include, for example, calcium carbonate, talc, and organic bentonite.

[0086] The proportion of the filler relative to 100 parts by mass of the resin component is, for example, 50 parts by mass or more, preferably 110 parts by mass or more, and for example, 300 parts by mass or less, preferably 200 parts by mass or less.

[0087] Pigments include, for example, carbon black and zinc oxide.

[0088] The proportion of the pigment relative to 100 parts by mass of the resin component is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and for example, 10 parts by mass or less, preferably 7 parts by mass or less.

[0089] (2) Restriction layer 3 The constraining layer 3 is disposed on the first surface S1 of the resin layer 2. The constraining layer 3 constrains the reinforcing layer 5, which will be described later. The constraining layer 3 constrains the reinforcing layer 5, thereby improving the toughness of the reinforcing layer 5. The constraining layer 3 has a predetermined thickness in the thickness direction of the resin layer 2.

[0090] The thickness of the constraining layer 3 is, for example, 0.01 mm or more, preferably 0.05 mm or more, and for example, 3 mm or less, preferably 1 mm or less.

[0091] Examples of materials for the constraining layer 3 include metals and glass fibers. Examples of metals include aluminum and copper. A preferred example of the metal is aluminum. A preferred example of the glass fibers is resin-impregnated glass cloth.

[0092] (3) Release sheet 4 The release sheet 4 is placed on the second surface S2 of the resin layer 2. When placed on the second surface S2 of the resin layer 2, the release sheet 4 protects the resin layer 2. The release sheet 4 is removable from the resin layer 2. As the release sheet 4, for example, known release paper can be used.

[0093] 2. Reinforcement method Next, a method for reinforcing the object to be reinforced P with the reinforcing material 1 will be described.

[0094] As shown in Figures 2A and 2B, the reinforcement method includes an attachment process (see Figure 2A) of attaching the reinforcing material 1 to the reinforcement object P, and a curing process (see Figure 2B) of thermally curing the resin layer 2 while the reinforcing material 1 is attached to the reinforcement object P.

[0095] 2A, in the attachment step, the worker peels off the release sheet 4 from the resin layer 2 and brings the second surface S2 of the resin layer 2 into contact with the object to be reinforced P. The reinforcing material 1 is attached to the object to be reinforced P due to the adhesive force of the resin layer 2.

[0096] Next, in the curing step, the worker heats the reinforcement object P to which the reinforcing material 1 has been attached.

[0097] The heating temperature is, for example, equal to or higher than the decomposition temperature of the foaming agent, or equal to or lower than a temperature 100° C. higher than the decomposition temperature of the foaming agent.

[0098] When the foaming agent is OBSH, the heating temperature is, for example, 130°C or more, preferably 150°C or more, and for example, 265°C or less, preferably 220°C or less.

[0099] The heating time is, for example, 5 minutes or more, preferably 10 minutes or more, and for example, 60 minutes or less, preferably 30 minutes or less.

[0100] In the curing step, the resin layer 2 is foamed and cured, as shown in FIGS. 2A and 2B.

[0101] Specifically, in the curing step, heating softens the resin component in the resin layer 2. As described above, the viscosity of the softened resin component at the decomposition temperature of the foaming agent is, for example, 500 Pa s or more, or preferably 1000 Pa s or more, and for example, 4000 Pa s or less, or preferably 3500 Pa s or less.

[0102] With the resin component in a softened state, the foaming agent decomposes, causing the resin layer 2 to foam. With the resin layer 2 in a foamed state, the resin component hardens, causing the resin layer 2 to harden. When hardening of the resin layer 2 is complete, the resin layer 2 becomes the reinforcing layer 5. In other words, the reinforcing layer 5 is a hardened product of the resin layer 2. The reinforcing layer 5 is fixed to the object P to be reinforced.

[0103] As shown in FIG. 3, the reinforcing layer 5 contains a matrix resin 51 formed by hardening a resin component, and a plurality of bubbles 52 formed by foaming of the foaming agent.

[0104] The ratio of the total area of the bubbles 52 in the cross section of the reinforcing layer 5 (porosity) is 83% or more. The ratio of the total area of the bubbles 52 in the cross section of the reinforcing layer 5 is measured by the method described in the examples below. The ratio of the total area of the bubbles 52 in the cross section of the reinforcing layer 5 can be adjusted by the viscosity of the softened resin component and the ratio of the foaming agent in the resin layer 2.

[0105] The proportion of the total area of the plurality of cells 52 in the cross section of the reinforcing layer 5 is preferably 83% or more, for example, 90% or less, preferably 88% or less.

[0106] When the ratio of the total area of the plurality of cells 52 in the cross section of the reinforcing layer 5 is equal to or greater than the above lower limit, the thickness of the reinforcing layer 5 can be increased.

[0107] The expansion ratio of the resin layer 2 (thickness of the reinforcing layer 5 / thickness of the resin layer 2) is, for example, 3 times or more and, for example, 5 times or less.

[0108] The average diameter of the cells 52 is, for example, 100 μm or more, preferably 200 μm or more, and for example, 2000 μm or less, preferably 1000 μm or less. When the ratio of the total area of the cells 52 in the cross section of the reinforcing layer 5 is the same, the average diameter of the cells 52 affects the breaking strength of the reinforcing member 11. However, with respect to the 1 mm bending elasticity, since the bending of the reinforcing member 11 is small, the average diameter of the cells 52 has almost no effect on the 1 mm bending elasticity.

[0109] The elastic modulus of the matrix resin 51 of the reinforcing layer 5 is 1.4 GPa or more. The elastic modulus of the matrix resin 51 of the reinforcing layer 5 can be adjusted by the ratio of the thermosetting resin to the rubber.

[0110] The matrix resin 51 of the reinforcing layer 5 has an elastic modulus of, for example, 5.0 GPa or less, or preferably 4.5 GPa or less.

[0111] If the proportion of resin components in the resin layer 2 is the same, the 1 mm bending elasticity tends to be higher when the elastic modulus of the base resin 51 of the reinforcing layer 5 is higher and the proportion of the total area of the multiple bubbles 52 in the cross section of the reinforcing layer 5 is higher.

[0112] Therefore, by making the elastic modulus of the base resin 51 of the reinforcing layer 5 1.4 GPa or more and making the total area ratio of the multiple bubbles 52 in the cross section of the reinforcing layer 5 83% or more, the reinforcing performance of the reinforcing member 11 can be improved.

[0113] When the curing process is completed, a reinforcement structure 10 is formed as shown in FIG. 2B. The reinforcement structure 10 includes a reinforcement object P and a reinforcing member 11. The reinforcing member 11 includes a reinforcing layer 5 and a constraining layer 3. The reinforcing member 11 reinforces the reinforcement object P. The reinforcing layer 5 is disposed on top of the reinforcement object P. The reinforcing layer 5 reinforces the reinforcement object P. The constraining layer 3 is disposed on top of the reinforcing layer 5. The constraining layer 3 is disposed on the opposite side of the reinforcing layer 5 from the reinforcement object P in the thickness direction of the reinforcing layer 5.

[0114] 3. Effects According to this reinforcing material 1, as shown in Figure 2B, the reinforcing layer 5 obtained by foaming and curing the resin layer 2 has an elastic modulus of the base resin 51 of the reinforcing layer 5 of 1.4 GPa or more, and the total area ratio of the multiple bubbles 52 in the cross section of the reinforcing layer 5 is 83% or more.

[0115] Therefore, the reinforcing performance of the reinforcing material 1 can be improved. [Example]

[0116] Next, the present invention will be described based on examples and comparative examples. The present invention is not limited to the following examples. Furthermore, specific numerical values of physical properties, parameters, etc. used in the following description can be replaced with the upper limit (a numerical value defined as "less than or equal to") or lower limit (a numerical value defined as "more than or equal to") of the corresponding physical properties, parameters, etc. described in the above "Description of the Invention."

[0117] (1) Preparation of the resin layer For each of the Examples and Comparative Examples, the materials shown in Tables 1 and 2 were mixed to prepare a resin composition.

[0118] The obtained resin composition was rolled to a thickness of 0.4 mm using a press molding machine to prepare a resin layer. A resin-impregnated glass cloth having a thickness of 0.2 mm was attached to one side of the obtained resin layer as a constraining layer, and a release paper was attached to the other side of the resin layer (the surface opposite to the one side). This resulted in a reinforcing material.

[0119] [Table 1]

[0120] [Table 2]

[0121] The materials in Tables 1 and 2 are explained below.

[0122] SBR: Styrene-butadiene rubber (product name: Tufden 2003, manufactured by Asahi Kasei Chemicals Corporation) NBR: Acrylonitrile butadiene rubber (product name: Nipol 1052J, manufactured by Zeon Corporation) Epoxy resin: Bisphenol A epoxy resin (trade name: jER-828, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 190 g / eq) Flexible epoxy resin: Dimer acid-modified epoxy resin (product name: YD-172, manufactured by Nippon Steel Chemical and Materials Co., Ltd., epoxy equivalent: 650 g / eq) Tackifying resin 1: C5 / C9 petroleum resin (product name: Petrotack 90HM, manufactured by Tosoh Corporation) Heavy calcium carbonate (Maruo Calcium Co., Ltd.) Carbon black (product name: Asahi #50, manufactured by Asahi Carbon Co., Ltd.) Sulfur (product name: Kinkajirushi fine powder sulfur, manufactured by Tsurumi Chemical Industry Co., Ltd.) Vulcanization accelerator (product name: DM, manufactured by Ouchi Shinko Chemical Co., Ltd.) Epoxy resin hardener (thermosetting resin hardener): Dicyandiamide (Nippon Carbide Corporation) Foaming agent: 4,4'-oxybis(benzenesulfonylhydrazide) (trade name: NeoCelvon N#1000S, manufactured by Eiwa Chemical Industry Co., Ltd.) (2) Measurement of porosity The release paper was peeled off and the reinforcing material of each example and comparative example was attached to the entire surface of a cold-rolled steel plate (manufactured by Nippon Test Panel Co., Ltd., SPCC-SD, width: 25 mm, length: 150 mm, thickness: 0.8 mm) to be reinforced.

[0123] Next, the steel plate with the reinforcing material attached was heated at 180°C for 20 minutes, which caused the resin layer to foam and harden, obtaining a reinforcing member (a reinforcing member including a reinforcing layer, which was the hardened resin layer, and a constraining layer) on the steel plate.

[0124] The obtained reinforcing member was peeled off from the steel plate, and the cross section of the reinforcing layer was observed under a microscope at 100 times magnification.

[0125] In a cross-sectional image (3000 μm×3000 μm) obtained by a microscope, the ratio of the total area of the plurality of bubbles in the cross section of the reinforcing layer was calculated using the following formula: The results are shown in Tables 1 and 2.

[0126] Formula: Porosity = total area of multiple bubbles / total area of reinforcement layer in cross-sectional image × 100 (3) Measurement of the elastic modulus of the base resin A reinforcing member was obtained on a steel plate under the same conditions as for measuring the porosity. The obtained reinforcing member was peeled off from the steel plate, and the elastic modulus of the matrix resin of the reinforcing layer was measured using a nanoindenter (testing machine: Triboindenter, manufactured by Hysitron Inc.).

[0127] The matrix resin of the reinforcing layer was pressed with a Berkovich indenter at a maximum load of 11,000 μN, and the elastic modulus was calculated based on the slope of the unloading curve from 20% to 85%. The results are shown in Tables 1 and 2.

[0128] (4) Measurement of 1mm bending strength A reinforcing member was obtained on the steel plate under the same conditions as those for measuring the porosity.

[0129] The test pieces, each comprising a steel plate and a reinforcing member, were supported at 100 mm intervals on a testing machine (a tensile / compression testing machine: Technograph TG-5KN, manufactured by MinebeaMitsumi Inc.) with the steel plate facing upward, and a test bar was lowered from above toward the center of the longitudinal direction of the test piece at a rate of 1 mm / min.

[0130] The bending strength (N) when the test bar descends 1 mm after contact with the steel plate is the 1 mm bending strength. The results are shown in Tables 1 and 2. [Explanation of symbols]

[0131] 1 Reinforcement 2 Resin layer 3 restraint layer 5 Reinforcement layer 51 Base resin 52 Bubbles 10 Reinforcement structure 11 Reinforcement member P Reinforcement target

Claims

1. A reinforcing material for reinforcing an object to be reinforced, a resin layer containing a resin component and a foaming agent and serving as a reinforcing layer for reinforcing the object to be reinforced; a constraining layer disposed on the resin layer; Equipped with The resin component contains a thermosetting resin and a rubber, The ratio of the thermosetting resin is more than 100 parts by mass relative to 100 parts by mass of the rubber, the thermosetting resin contains a flexible epoxy resin and an epoxy resin other than the flexible epoxy resin, the epoxy equivalent of the flexible epoxy resin is 220 g / ep or more, and the epoxy equivalent of the epoxy resin other than the flexible epoxy resin is less than 220 g / ep; a proportion of the flexible epoxy resin in the thermosetting resin is 10% by mass or more and less than 50% by mass; the reinforcing layer contains a matrix resin formed by the curing of the resin component and a plurality of bubbles generated by the foaming of the foaming agent, a ratio of a total area of the plurality of bubbles in a cross section of the reinforcing layer to 83% or more; A reinforcing material, wherein the matrix resin of the reinforcing layer has an elastic modulus of 1.4 GPa or more.

2. The rubber contains acrylonitrile butadiene rubber, 2. The reinforcing material according to claim 1, wherein the proportion of the acrylonitrile-butadiene rubber is 60 parts by mass or more relative to 100 parts by mass of the flexible epoxy resin.

3. The reinforcement target and a reinforcing member having the reinforcing layer and the constraining layer according to claim 1; A reinforcing structure comprising:

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