One-component curable composition

Abstract

To provide a pump-dispensable one-component curable composition for sheet-metal reinforcement that ensures pump dischargeability and shower resistance while capable of further improving strain resistance and reinforcing properties.SOLUTION: A pump-dispensable one-component curable composition for sheet-metal reinforcement comprises (A) an epoxy resin, (B) an elastomer, (C) a plasticizer, (D) a latent curing agent, (E) a filler, and (F) a foaming agent. The epoxy resin (A) includes at least (A1) an unmodified epoxy resin having a cyclic structure. The cured product has a modulus of elasticity at 23°C of 100 to 1,500 MPa, and Tg by DMA of 95 to 180°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a one-component curable composition, and more specifically to a one-component curable composition that is a coating type, comprising (A) an epoxy resin, (B) an elastomer, (C) a plasticizer, (D) a latent curing agent, (E) a filler, and (F) a foaming agent. [Background technology]

[0002] Thinner sheet metal is used to reduce the weight of automobile bodies. Sheet metal reinforcing materials are used to ensure the tensile rigidity and tentability of the sheet metal. Typically, sheet metal reinforcing materials have a three-layer structure of glass cloth, adhesive, and release paper, and are commercially available as standardized products with a specific plate shape. Such standardized sheet metal reinforcing materials are adjusted to the desired shape before use. The adjusted-shape sheet metal reinforcing materials are attached to the sheet metal, but manual adjustments are required due to factors such as reduced adhesiveness and misalignment of the attachment position caused by the usage environment. Therefore, fully automating sheet metal reinforcing using standardized sheet metal reinforcing materials is difficult, resulting in reduced productivity. Furthermore, disposal of the release paper can increase costs and create environmental impacts due to the generation of waste. Therefore, a fully automated sheet metal reinforcing material is needed. As such a sheet metal reinforcing material, an automatically applicable sheet metal reinforcing material has been investigated.

[0003] For example, Patent Document 1 discloses a spreadable sheet metal reinforcing material composition obtained by blending an inorganic filler with a specific aspect ratio (L / D) into a liquid composition of a thermosetting epoxy resin to form a highly viscous, viscous substance. Patent Document 1 discloses that the spreadable sheet metal reinforcing material composition can be applied under heating, and by allowing it to cool and solidify after application, it does not scatter, dissolve, or fall off during the process up to curing and baking, particularly in the case of shower resistance, chemical conversion treatment solutions, and electrolytes. It also discloses that the reinforcing effect improves the bending strength and rigidity of the sheet metal, and does not cause distortion in the sheet metal even after curing (see Patent Document 1

[0005] ). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3547404 specification Summary of the Invention [Problem to be solved by the invention]

[0005] The coatable sheet metal reinforcing material disclosed in Patent Document 1 has excellent properties, but there is a need to further improve the reinforcing properties while suppressing distortion and maintaining pump dischargeability and shower resistance. On the other hand, Patent Document 1 obtains a coatable sheet metal reinforcing material by making it a high-viscosity viscous material, and does not teach anything about improving bending strength, improving shower resistance, or maintaining low viscosity and pump dischargeability.

[0006] Therefore, an object of the present invention is to provide a one-component curable composition that can be applied by heating while maintaining a low viscosity, but that does not scatter, dissolve, or fall off during the process from application to curing and baking, particularly in the presence of showers, chemical conversion treatment solutions, and electrodeposition solutions, and that, after curing, further improves the bending strength and rigidity of sheet metal, particularly at high temperatures, but does not cause distortion of the sheet metal, particularly at low temperatures. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have found that by controlling both the modulus of elasticity at 23°C and the Tg of a cured product of a one-component curable composition within specific ranges, it is possible to obtain a one-component curable composition that can improve reinforcement (particularly reinforcement at high temperatures) and strain resistance (particularly strain resistance at low temperatures) while maintaining pumpability and shower resistance. Furthermore, they have found that such a one-component curable composition can be suitably applied to sheet metal and can be suitably used as a spreadable sheet metal reinforcing material, thereby completing the present invention.

[0008] The present specification includes the following embodiments. 1. A one-component curable composition comprising: (A) an epoxy resin; (B) an elastomer; (C) a plasticizer; (D) a latent curing agent; (E) a filler; and (F) a blowing agent, (A) The epoxy resin contains at least (A1) an unmodified epoxy resin having a cyclic structure, The elastic modulus of the cured product at 23°C is 100 to 1500 MPa, The glass transition temperature of the cured product measured by dynamic viscoelasticity measurement is 95 to 180°C. A pumpable, one-part curable composition for reinforcing sheet metal. 2. (B) Elastomer is (B1) diene-based solid rubber The one-component curable composition according to 1 above, further comprising (B2) a fine particle or liquid reactive elastomer. 3. The one-component curable composition according to 1 or 2 above, wherein the (A) epoxy resin contains 35 to 85 parts by mass of (A1) an unmodified epoxy resin having a cyclic structure, relative to 100 parts by mass of the total of (A), (B), and (D). 4. The one-component curable composition according to any one of 1 to 3 above, wherein the (A1) unmodified epoxy resin having a cyclic structure comprises a bisphenol A type epoxy resin, and the (A1) unmodified epoxy resin having a cyclic structure is contained in an amount of 50 to 100 parts by mass per 100 parts by mass of the epoxy resin (A). 5. The one-component curable composition according to any one of 1 to 4 above, wherein the filler (E) contains a needle-shaped filler, and the content of the needle-shaped filler is 30 to 50 mass % relative to 100 mass % of the entire composition. 6. The one-component curable composition according to any one of 1 to 5 above, wherein the foaming agent (F) contains at least one selected from an azo compound, a hydrazine compound, and thermally expandable particles, and has an expansion ratio of 1.1 to 3 times. 7.40℃, shear rate 430sec -1 7. The one-component curable composition according to any one of 1 to 6 above, having a viscosity of 50 to 300 Pa·s at 100°C. [Effects of the Invention]

[0009] The one-component curable composition according to the embodiment of the present invention can further improve strain resistance and reinforcement while ensuring pumpability and shower resistance. Furthermore, the one-component curable composition can be suitably applied to sheet metal and can be suitably used as a spreadable sheet metal reinforcing material. DETAILED DESCRIPTION OF THE INVENTION

[0010] In one aspect, the present specification A one-component curable composition comprising: (A) an epoxy resin; (B) an elastomer; (C) a plasticizer; (D) a latent curing agent; (E) a filler; and (F) a foaming agent, (A) The epoxy resin contains at least (A1) an unmodified epoxy resin having a cyclic structure, The elastic modulus of the cured product at 23°C is 100 to 1500 MPa, The glass transition temperature (Tg) of the cured product measured by dynamic mechanical analysis (DMA) is 95 to 180°C. A pumpable, one-part curable composition for reinforcing sheet metal is provided.

[0011] In this specification, the (A) epoxy resin refers to a thermosetting resin that can be cured by forming a crosslinked network through the epoxy groups present therein, and is generally called an epoxy resin. There are no particular limitations on the type of epoxy resin, as long as the one-component curable composition that is the object of the present invention can be obtained. The (A) epoxy resin may be, for example, a glycidyl ether type epoxy resin, a glycidyl amine type epoxy resin, or a glycidyl ester type epoxy resin.

[0012] The (A) epoxy resin preferably contains (A1) an unmodified epoxy resin having a cyclic structure. The (A1) unmodified epoxy resin having a cyclic structure is, for example, an epoxy resin having a cyclic structure such as a bisphenol skeleton having an aromatic ring, and is not particularly limited as long as it is not particularly modified and can give the one-component curable composition of the present invention. (A1) Examples of unmodified epoxy resins having a cyclic structure include diglycidyl ethers of bisphenol A, bisphenol F, brominated bisphenol A, and bisphenol AD. The (A1) unmodified epoxy resin having a cyclic structure preferably includes one selected from bisphenol A type epoxy resins, bisphenol F type epoxy resins, brominated bisphenol A type epoxy resins, bisphenol AD ​​type epoxy resins, naphthalene type epoxy resins, glycidylamine type epoxy resins, and the like.

[0013] The viscosity of the (A1) unmodified epoxy resin having a cyclic structure at 25°C is preferably 1500 mPa·s or more, more preferably 2000 to 25000 mPa·s, even more preferably 2500 to 20000 mPa·s, and even more preferably 3000 to 15000 mPa·s. The (A1) unmodified epoxy resin having a cyclic structure preferably has an epoxy equivalent weight of 150 to 800 g / eq, more preferably 160 to 500 g / eq, even more preferably 165 to 250 g / eq, and even more preferably 170 to 200 g / eq. When the (A1) unmodified epoxy resin having a cyclic structure has an epoxy equivalent weight of 150 to 800 g / eq, workability is superior. (A1) The unmodified epoxy resin having a cyclic structure may be a commercially available product, such as "jER (registered trademark) 828," "jER (registered trademark) 1001," or "jER (registered trademark) 807" manufactured by Mitsubishi Chemical Corporation.

[0014] The (A) epoxy resin preferably contains 50 to 100 mass %, more preferably 65 to 100 mass %, and even more preferably 80 to 100 mass % of the (A1) unmodified epoxy resin having a cyclic structure, based on 100 mass % of the (A) epoxy resin. When the epoxy resin (A) contains 50 to 100 mass% of the unmodified epoxy resin (A1) having a cyclic structure, relative to 100 mass% of the epoxy resin (A), the one-component curable composition according to an embodiment of the present invention can exhibit improved Tg, elastic modulus, and flexural strength in a more balanced manner.

[0015] The content of the unmodified epoxy resin having a cyclic structure (A1) is preferably 35 to 85 parts by mass, more preferably 50 to 85 parts by mass, more preferably 50 to 80 parts by mass, and even more preferably 65 to 80 parts by mass, based on 100 parts by mass of the total of the epoxy resin (A), the elastomer (B), and the latent curing agent (D). When the one-component curable composition according to an embodiment of the present invention contains 35 to 85 parts by mass of (A1) an unmodified epoxy resin having a cyclic structure, relative to 100 parts by mass of the total of the epoxy resin (A), the elastomer (B), and the latent curing agent (D), the composition has superior glass transition temperature, elastic modulus, and flexural strength.

[0016] The (A) epoxy resin may include (A2) low-viscosity epoxy resin, which is defined as an epoxy resin other than (A1) that has a viscosity of less than 2000 mPa·s at 25°C. When the epoxy resin (A) includes a low-viscosity epoxy resin (A2), the curable composition according to an embodiment of the present invention can better ensure pumpability at 40 to 50°C and can be better imparted with flexibility (enables a larger displacement amount at maximum strength in a bending test).

[0017] The number of functional groups in the (A2) low-viscosity epoxy resin may be 1, 2, 3, or 4 or more, but when the (A2) low-viscosity epoxy resin has 1 or 2 functional groups, it is possible to ensure better dischargeability and impart better flexibility. When the (A2) low-viscosity epoxy resin has 3 or 4 or more functional groups, it is possible to ensure better dischargeability and prevent a decrease in heat resistance.

[0018] Specific examples of (A2) low-viscosity epoxy resins include dibasic acid ester-based epoxy resins, polyalkylene glycol-based epoxy resins, aliphatic glycidyl ethers, aromatic monoglycidyl ethers, and aliphatic triglycidyl ethers. Commercially available low-viscosity epoxy resins can be used, such as ERISYS GE30, GE-25, GE-24, GE-11, and GE8 manufactured by CVC Thermoset Specialties.

[0019] The (A) epoxy resin may or may not contain the (A2) low-viscosity epoxy resin, but may contain 5% by mass or less of the (A2) low-viscosity epoxy resin, based on 100% by mass of the (A) epoxy resin. When the (A) epoxy resin does not contain the (A2) low-viscosity epoxy resin or contains 5% by mass or less of the (A2) low-viscosity epoxy resin, based on 100% by mass of the (A) epoxy resin, the one-component curable composition of the present invention can better ensure pumpability at 40 to 50°C and can have better flexibility and heat resistance. The low-viscosity epoxy resin (A2) does not include the unmodified epoxy resin (A1) having a cyclic structure.

[0020] The (A) epoxy resin may contain (A3) other epoxy resins that do not fall under either the (A1) unmodified epoxy resin having a cyclic structure or the (A2) low-viscosity epoxy resin. The (A3) other epoxy resin is an epoxy resin that does not fall under the category of (A1) unmodified epoxy resin having a cyclic structure and (A2) low-viscosity epoxy resin, and is not particularly limited as long as the one-component curable composition targeted by the present invention can be obtained. The (A) epoxy resin may contain (A3) other epoxy resin in an amount of 40% by mass or less, 30% by mass or less, or 20% by mass or less, based on 100% by mass of the (A) epoxy resin. (A3) As other epoxy resins, commercially available products can be used, such as dimer acid-modified bisphenol A epoxy resin (JER872 (trade name) manufactured by Mitsubishi Chemical Corporation) and polyoxyalkylene-modified bisphenol A epoxy resin (EP-4000 (trade name) manufactured by ADEKA Corporation).

[0021] In this specification, the term "(B) elastomer" refers to a polymeric material having elastomeric properties (rubber elasticity) and is not particularly limited as long as it can provide the composition of the present invention. The purpose of using the (B) elastomer in the present invention is to improve shower resistance, reduce brittleness of the cured product, and achieve both strain resistance and reinforcement. Specifically, in order to improve shower resistance, the elastomer (B) preferably contains a diene solid rubber (B1), which can impart high viscosity and stickiness to the composition. Furthermore, the (B) elastomer preferably contains (B2) a particulate or liquid reactive elastomer. The use of (B2) a particulate or liquid reactive elastomer can further improve the brittleness of the composition (imparting greater flexibility) and increase the maximum bending displacement. Examples of (B2) a particulate or liquid reactive elastomer include polyurethane prepolymers having active isocyanates, butadiene-based polymers having functional groups (including copolymers with acrylonitrile and / or styrene, etc.), core-shell rubber particles, and blocked isocyanates, and these are preferred. The (B) elastomer may be contained in the composition alone or in combination of two or more kinds, may be mixed and / or dispersed in the composition, or may be pre-reacted with the epoxy resin to become part of the epoxy resin.

[0022] The form of the elastomer (B) is not particularly limited as long as the composition aimed at by the present invention can be obtained. The (B) elastomer preferably contains at least one selected from (B1) diene-based solid rubber and (B2) particulate or liquid reactive elastomer, and may further contain (B3) an elastomer not classified as one of the above elastomers.

[0023] In this specification, the term "(B1) diene-based solid rubber" refers to a rubber-like substance that is solid at 23°C and that may exist in a dissolved or swollen state upon contact with a liquid substance such as the (A) epoxy resin or (C) plasticizer in the composition, and does not include (B2) fine particles or liquid reactive elastomer. There are no particular limitations on the (B1) diene-based solid rubber, as long as it can provide the curable composition of the present invention. In this specification, the term "solid" in "solid rubber" means that the rubber is solid at room temperature (23°C). When rubber and a liquid component coexist, this means that the portion of the rubber excluding the liquid component is solid at room temperature (23°C). Therefore, even if rubber coexists with a liquid component at room temperature and may dissolve and / or swell, if the rubber is solid at room temperature (23°C) after the liquid component is removed, it falls under the category of solid rubber.

[0024] The diene-based solid rubber (B1) preferably contains at least one selected from diene-based polymers and copolymers such as butadiene polymers, isoprene polymers, acrylonitrile-butadiene copolymers, styrene-butadiene copolymers, styrene-butadiene-divinylbenzene copolymers, ethylene-propylene-diene copolymers, etc. In this case, the curable composition according to the embodiment of the present invention has better shape retention (showerability). The (B1) diene solid rubber preferably contains 3 to 100 mass % of a diene polymer and / or copolymer, based on 100 mass % of the (B) elastomer, more preferably 5 to 90 mass %, even more preferably 10 to 80 mass %, and even more preferably 20 to 70 mass %.

[0025] The one-component curable composition according to an embodiment of the present invention may contain, for example, 10 to 100 parts by mass of the (B) elastomer per 100 parts by mass of the (A) epoxy resin, preferably 20 to 90 parts by mass of the (B) elastomer, more preferably 30 to 80 parts by mass of the (B) elastomer, and still more preferably 40 to 70 parts by mass of the (B) elastomer. When the one-component curable composition according to the embodiment of the present invention contains 10 to 100 parts by mass of the (B) elastomer per 100 parts by mass of the (A) epoxy resin, the one-component curable composition according to the embodiment of the present invention is more excellent in shape retention (showerability) and flexibility (improved maximum bending displacement).

[0026] In this specification, the term "(B2) fine particle or liquid reactive elastomer" refers to an elastomer having reactive groups for incorporation into the epoxy resin network, and includes not only rubber particles having functional groups and reactive elastomers having thermally dissociable blocked isocyanates, but also the elastomer portion contained in epoxy resins modified with the (B2) liquid reactive elastomer, such as urethane-modified epoxy resins and rubber-modified epoxy resins. The term "(B2) fine particle or liquid reactive elastomer" refers to an elastomer that is incorporated into the epoxy resin network, and therefore may be present as a reactive elastomer as is in the one-component curable composition, or the reactive elastomer may, for example, pre-react with the epoxy resin to become part of the epoxy resin.

[0027] The (B2) fine particle or liquid reactive elastomer may contain, for example, at least one functional group selected from an acid anhydride group, a carboxy group, an amino group, an imino group, an epoxy group, an isocyanate group, a blocked isocyanate group, etc. When the (B) elastomer is reacted with an epoxy resin in advance, it preferably contains at least one selected from an acid anhydride group, a carboxy group, an amino group, and an imino group, and when the (B) elastomer is dispersed or mixed with the (A) epoxy resin in a one-component curable composition, it preferably contains at least one selected from an epoxy group and a blocked isocyanate group (a deactivated isocyanate group).

[0028] One example of the form of the (B2) fine particle or liquid reactive elastomer is an elastomer-containing particle having a core-shell structure, which has a core made of an elastomer such as polybutadiene and a shell containing a polymer having epoxy groups. These particles can be handled in the form of a dispersion in an epoxy resin. For example, the shape of the elastomer-containing fine particles may be spherical, and the diameter thereof may be, for example, 50 to 5000 nm, 150 to 3000 nm, 200 to 1000 nm, or 250 to 550 nm.

[0029] The core of the core-shell structure is made of an elastomer, and may be an elastomer such as butadiene polymer, isoprene polymer, acrylonitrile butadiene copolymer, styrene-butadiene copolymer, butyl acrylate, or polydimethylsiloxane. The shell of the core-shell structure can be appropriately selected in consideration of compatibility with the epoxy resin, and may be, for example, an acrylic polymer, a vinyl polymer, or a copolymer thereof. The (B) elastomer contained in the particles can be dispersed in the (A) epoxy resin to prepare a masterbatch. Commercially available masterbatches are available, such as Kaneka Ace MX-150 (trade name) and MX-257 (trade name) manufactured by Kaneka.

[0030] Another form of the (B2) particulate or liquid reactive elastomer may be a urethane prepolymer in which an active isocyanate is blocked with a thermal release blocking agent. The urethane prepolymer may be a blocked isocyanate in which a reaction product of a polyol having elastomeric properties and a polyisocyanate is blocked with a blocking agent. Examples of polyols having elastomeric properties include polyether polyols, polyester polyols, polyolefin polyols, and diene polyols.

[0031] Examples of polyisocyanates include hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, toluene diisocyanate, methylene diphenyl diisocyanate, and polymers thereof. The molecular weight of the polyol is preferably 1000 to 40000, more preferably 2000 to 20000, and even more preferably 3000 to 15000. When the molecular weight of the polyol is 1000 to 40000, excellent flexibility is achieved. Specific examples include B7005 manufactured by Mitsui Chemicals, Inc. and QR9644 manufactured by ADEKA Corporation.

[0032] Another form of the (B2) particulate or liquid reactive elastomer may be a urethane-modified epoxy resin obtained by reacting a prepolymer of a polyol having an isocyanate group at its terminal and a polyisocyanate with a hydroxyl group in an epoxy resin. Examples of polyols having elastomeric properties include polyether polyols, polyester polyols, polyolefin polyols, and diene polyols. Examples of polyisocyanates include hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, toluene diisocyanate, methylene diphenyl diisocyanate, and polymers thereof. The molecular weight of the polyol is preferably from 1000 to 40000, more preferably from 2000 to 20000, and even more preferably from 3000 to 15000. When the molecular weight of the polyol is from 1000 to 40000, the flexibility is excellent. Specifically, EPU-6 manufactured by ADEKA Corporation can be exemplified.

[0033] Another form of the (B2) particulate or liquid reactive elastomer may be a rubber-modified epoxy resin obtained by reacting a butadiene-acrylonitrile copolymer having a carboxyl group with an epoxy resin. Examples of acrylonitrile butadiene copolymers having a carboxyl group include copolymers of acrylic acid, acrylonitrile and butadiene, and carboxy-terminated butadiene nitrile rubber. Specific examples of butadiene acrylonitrile rubbers having a carboxylic acid include Nipol DN-601 manufactured by Zeon Corporation and Hypro1300x8CTBN and Hypro1300x13CTBN manufactured by Huntsman Co., Ltd. Furthermore, a specific example of rubber-modified epoxy resins modified with these rubbers is HyPox RA840 manufactured by Huntsman Co., Ltd.

[0034] The (B) elastomer can contain at least one selected from (B1) diene-based solid rubber, (B2) particulate or liquid reactive elastomer, and (B3) an elastomer that does not belong to either (B1) or (B2). (B1) Diene-based solid rubber refers to diene-based solid rubber that is processed by masticating it with force and heat using a processing machine, and then swelling and plasticizing (liquefying) at least liquid resins and plasticizers. (B2) Particulate or liquid reactive elastomer refers to an elastomer having reactive groups that can be incorporated into the epoxy resin network after reaction. For example, diene rubber particles that are reactive with epoxy resin and epoxy resin curing agents are reactive elastomers. Elastomers that do not fall under either (B1) or (B2) are classified as (B3). Examples of (B3) include solid rubbers (including particulate rubbers) other than diene-based rubbers and liquid rubbers that do not have reactivity (reactive groups).

[0035] The one-component thermosetting adhesive composition according to an embodiment of the present invention comprises, based on 100 parts by mass of the total of (A) the epoxy resin, (B) the elastomer, and (D) the latent curing agent, It is preferable that the composition contains (A1) 40 parts by mass or more and 90 parts by mass or less of an unmodified epoxy resin having a cyclic structure and (B1) 2 parts by mass or more and 20 parts by mass or less of a solid rubber, It is more preferable that the composition contains (A1) 50 parts by mass or more and 80 parts by mass or less of an unmodified epoxy resin having a cyclic structure and (B1) 3 parts by mass or more and 15 parts by mass or less of a solid rubber, It is even more preferable that the composition contains (A1) 60 parts by mass or more and 75 parts by mass or less of an unmodified epoxy resin having a cyclic structure and (B1) 5 parts by mass or more and 10 parts by mass or less of a solid rubber. The one-component thermosetting adhesive composition according to an embodiment of the present invention comprises, based on 100 parts by mass of the total of (A) the epoxy resin, (B) the elastomer, and (D) the latent curing agent, (A1) An unmodified epoxy resin having a cyclic structure is contained in an amount of 40 parts by mass or more and 70 parts by mass or less, and (B1) A solid rubber is contained in an amount of 3 parts by mass or more and 10 parts by mass or less, The one-component thermosetting adhesive composition according to an embodiment of the present invention exhibits the advantageous effect of achieving both Tg, modulus of elasticity, and flexural strength, as well as shower resistance.

[0036] The one-component curable composition according to the embodiment of the present invention may contain a plasticizer (C). In this specification, the plasticizer (C) is not particularly limited as long as it can increase plasticity and can provide the one-component curable composition that is the object of the present invention.

[0037] Examples of the plasticizer include phthalates, benzoates, adipates, glutarates, trimellitates, phosphates, polyester plasticizers, epoxy plasticizers, process oil, and liquid paraffin. Specifically, butyl benzyl phthalate (butyl benzyl phthalate: BBP), octyl benzyl phthalate (octyl benzyl phthalate: OBP), isononyl benzyl phthalate (isononyl benzyl phthalate), dimethyl cyclohexyl phthalate (dimethyl cyclohexyl phthalate: DMCHP), phthalate polyester, diisononyl phthalate (diisononyl phthalate: DINP), dioctyl phthalate (dioctyl phthalate: DOP), dimethyl phthalate (dimethyl phthalate: DMP), diethyl phthalate (diethyl phthalate: DEP), dibutyl phthalate (dibutyl phthalate: DBP), diheptyl phthalate (diheptyl phthalate: DHP), phthalic acid Examples include phthalate diesters such as dinonyl (dinonyl phthalate: DNP), didecyl phthalate (didecyl phthalate: DDP), di-normal octyl phthalate (di-normal octyl phthalate: DnOP), diisodecyl phthalate (diisodecyl phthalate: DIDP), and bis-2-ethylhexyl phthalate (bis-2-ethyl phthalate: DEHP); cyclohexanedicarboxylic acid diesters such as diisononyl cyclohexanedicarboxylate; and trimellitic acid triesters such as trimellitic acid tris (trioctyl trimellitate: TOTM), trioctyl trimellitate (TOTN), triisooctyl trimellitate, and triisodecyl trimellitate.

[0038] The (C) plasticizer preferably contains a plasticizer having a solubility parameter (SP value) calculated using Small's constant of 7.0 to 9.2, and more preferably 7.5 to 9.0 (J / cm 3 ) 1 / 2 It is more preferable that the resin contains a plasticizer having a viscosity of 8.0 to 8.9 (J / cm 3 ) 1 / 2 It is more preferred that the composition contains a plasticizer in the form of The solubility parameter (SP value) calculated using Small's constant refers to the value δ calculated by the following Small's formula. δ=dΣG / M In the formula, d represents density, G represents the intermolecular attractive constant (Small's constant), and M represents molecular weight. For example, the SP value of diisononyl phthalate is 8.9 (J / cm 3 ) 1 / 2 The SP value of diisononyl adipate is 8.5 (J / cm 3 ) 1 / 2 The SP value of diisodecyl phthalate is 8.6 (J / cm 3 ) 1 / 2 The SP value of diisodecyl adipate is 8.3 (J / cm 3 ) 1 / 2 The SP value of diundecyl phthalate is 8.7 (J / cm 3 ) 1 / 2 is.

[0039] (C) The plasticizer has a solubility parameter of 7.0 to 9.2 (J / cm 3 ) 1 / 2 When a plasticizer containing this compound is included, the plasticizer has poor compatibility with the epoxy resin, and when the cured product separates into an epoxy resin layer and a rubber layer, the plasticizer is incorporated into the rubber layer, which is thought to help lower the Tg of the rubber layer without lowering the Tg of the epoxy resin layer. This results in better strain resistance at low temperatures (reduced warpage at low temperatures) while maintaining the heat resistance of the composition. The solubility parameter is 7.0 (J / cm 3 ) 1 / 2 If the solubility parameter is lower than 9.2 (J / cm), the compatibility with the composition may become too poor and the cured product may tend to become brittle. 3 ) 1 / 2 If the temperature is too high, the epoxy resin may be plasticized, lowering Tg and decreasing heat resistance. (C) Plasticizers containing diisononyl phthalate, diisononyl adipate, etc. are more preferable, including from the viewpoint of economy.

[0040] The one-component curable composition according to an embodiment of the present invention may contain, for example, 3 to 20 parts by mass, preferably 4 to 15 parts by mass, more preferably 5 to 15 parts by mass, and even more preferably 7 to 13 parts by mass of the plasticizer (C), relative to 100 parts by mass of the entire one-component curable composition. When the one-component curable composition according to the present invention contains 3 to 20 parts by mass of plasticizer, based on 100 parts by mass of the entire composition, the viscosity of the composition can be reduced, and the strain resistance at low temperatures (reduction of warpage at low temperatures) can be improved while maintaining the heat resistance (Tg). When the plasticizer is contained in an amount less than 3 parts by mass, based on 100 parts by mass of the entire composition, the viscosity is not sufficiently reduced, which may result in poor dischargeability. When the plasticizer is contained in an amount greater than 20 parts by mass, based on 100 parts by mass of the entire composition, the physical properties (elastic modulus and displacement at break) may tend to be reduced.

[0041] In this specification, the term (D) latent curing agent refers to a compound that is a curing agent for the (A) epoxy resin, but does not substantially function as a curing agent at room temperature, but functions as a curing agent when heated (for example, to 170°C), and is not particularly limited as long as the curable composition targeted by the present invention can be obtained.

[0042] Specific examples of latent curing agents include dicyandiamide; dihydrazide compounds such as adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, dodecanediohydrazide, 1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin, eicosanedioic acid dihydrazide, hydroquinone diglycolic acid dihydrazide, resorcinol diglycolic acid dihydrazide, and 4,4'-ethylidenebisphenol diglycolic acid dihydrazide; 4,4'-diaminodiphenyl sulfone; imidazole compounds such as imidazole, 2-n-heptadecylimidazole, and 2-undecylimidazole; melamine; 2,4-diamino-6-( Examples of the compound include triazine compounds such as 2'-methylimidazolinone(1')-ethyl-o-triazine; benzoguanamine; dialkyl urea compounds such as N,N-dialkyl ureas and N,N'-dialkyl urea compounds such as N,N-dimethyl-N'-(3,4-dichlorophenyl) urea; N,N'-dialkylthiourea compounds; polyamines such as diaminodiphenylmethane, diaminobiphenyl, diaminophenyl, phenylenediamine, tolylenediamine, dodecanediamine, decanediamine, octanediamine, tetradecanediamine, hexadecanediamine, polyoxypropylenediamine, and hydrazide-based polyamines; and guanidine derivatives such as cyanoguanidine.

[0043] Commercially available latent curing agents can be used, such as CG-NA (trade name) manufactured by Air Products, EH-4070s (trade name) manufactured by ADEKA, ADH (trade name) manufactured by Otsuka Chemical, EH3731s (trade name) manufactured by ADEKA, Dyhard UR200 (trade name) manufactured by AlzChem, and DDH (trade name) manufactured by Otsuka Chemical.

[0044] The one-component curable composition of the embodiment of the present invention may contain, for example, 1 to 30 parts by mass of the latent curing agent (D) per 100 parts by mass of the epoxy resin (A), preferably 2 to 25 parts by mass of the latent curing agent (D), more preferably 3 to 20 parts by mass of the latent curing agent (D), and even more preferably 4 to 15 parts by mass of the latent curing agent (D). The one-component curable composition according to an embodiment of the present invention has excellent storage stability and curability when it contains 1 to 30 parts by mass of the latent curing agent (D) per 100 parts by mass of the epoxy resin (A).

[0045] In this specification, the (E) filler refers to a compound that increases the amount of the one-component curable composition according to an embodiment of the present invention and can impart a certain degree of strength to a cured product formed from the one-component curable composition, and in some cases can contribute to viscosity adjustment or weight reduction. There are no particular limitations on the filler as long as it can provide the one-component curable composition that is the object of the present invention.

[0046] (E) Fillers, for example, calcium carbonate (heavy calcium carbonate, precipitated calcium carbonate, surface-treated calcium carbonate, etc.), magnesium carbonate, alkaline earth metal carbonates and sulfates such as barium sulfate, mica, graphite, talc, clay, glass flakes (glass beads), vermiculite, kaolinite, wollastonite (acicular calcium metasilicate), silica, carbon, diatomaceous earth, gypsum, cement, converter slag, shirasu, zeolite, cellulose powder, powdered rubber, zonolite, potassium titanate, bentonite, aluminum nitride, silicon nitride, zinc oxide, titanium oxide, alumina, zinc oxide, iron oxide, magnesium oxide, titanium oxide, magnesium hydroxide, hydroxide Examples of fillers include aluminum, calcium silicate, calcium carbonate whiskers (needle-shaped calcium carbonate), ceramic short fibers or whiskers thereof, rock wool short fibers, glass fiber short fibers, potassium titanate short fibers, calcium silicate short fibers, aluminum silicate, carbon fiber short fibers, aramid fiber short fibers, mineral fibers such as sepiolite, various whiskers, and other fibrous fillers; hollow fillers such as glass balloons, ceramic balloons, silica balloons, resin balloons, and inorganic carbon hollow spheres; organic hollow fillers such as plastic balloons made of organic synthetic resins such as vinylidene chloride and acrylonitrile; and metallic fillers such as aluminum filler.

[0047] (E) The filler preferably includes needle-shaped fillers having a length of 0.4 mm or more, more preferably includes needle-shaped fillers having a length of 0.4 mm or more and 40 mm or less, even more preferably includes needle-shaped fillers having a length of 5 mm or more and 30 mm or less, and even more preferably includes needle-shaped fillers having a length of 6 mm or more and 20 mm or less. When the (E) filler contains a needle-shaped filler having a length of 0.4 mm or more, the strain resistance of the one-component curable composition according to an embodiment of the present invention can be further improved.

[0048] The (E) filler preferably contains an inorganic filler having an aspect ratio (L / D) of 4 or more, more preferably contains an inorganic filler having an aspect ratio (L / D) of 4.5 or more and 20 or less, and even more preferably contains an inorganic filler having an aspect ratio (L / D) of 5 or more and 15 or less. When the (E) filler contains an inorganic filler with an aspect ratio (L / D) of 4 or more, the strain resistance of the one-component curable composition according to an embodiment of the present invention can be further improved.

[0049] In addition, examples of inorganic fillers include fillers other than organic fillers (e.g., hollow fillers such as rock wool short fibers, aramid fiber short fibers, and resin balloons, and organic hollow fillers such as plastic balloons made of organic synthetic resins such as vinylidene chloride and acrylonitrile) from the above-mentioned exemplary fillers.

[0050] The one-component curable composition of the present invention may contain, for example, 30 to 75 parts by mass of the filler (E) per 100 parts by mass of the curable composition, preferably 35 to 65 parts by mass of the filler (E), more preferably 40 to 60 parts by mass of the filler (E), and still more preferably 45 to 58 parts by mass of the filler (E). The curable composition according to an embodiment of the present invention has better shape retention (shower resistance) when it contains 30 to 75 parts by mass of the filler (E) per 100 parts by mass of the curable composition.

[0051] The (E) filler may contain, for example, 30 to 50 parts by mass of needle-shaped filler per 100 parts by mass of the one-component curable composition, preferably 32 to 48 parts by mass of needle-shaped filler, more preferably 34 to 46 parts by mass of needle-shaped filler, and even more preferably 36 to 44 parts by mass of needle-shaped filler. When the (E) filler contains 30 to 50 parts by mass of needle-shaped filler per 100 parts by mass of the curable composition, the distortion resistance (warpage amount) is superior.

[0052] In this specification, the term (F) foaming agent refers to a substance added to increase the volume of the material, for example, a substance added to generate bubbles, and is, for example, a substance that generates a gas upon decomposition or a substance that becomes a gas itself, and is not particularly limited as long as the one-component curable composition targeted by the present invention can be obtained. The one-component curable composition according to the embodiment of the present invention contains a foaming agent (F), which can more efficiently increase the thickness after curing and improve the reinforcing properties. Furthermore, foaming can reduce the elastic modulus of the cured product (i.e., the reinforcing material) obtained by curing the curable composition, and can also reduce strain.

[0053] As the (F) foaming agent, for example, a foaming agent that foams upon heating is preferred, and examples thereof include inorganic foaming agents and organic foaming agents. Examples of inorganic foaming agents include ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, and azides. Examples of organic blowing agents include n-nitroso compounds, azo compounds (e.g., azodicarbonamide; ADCA), fluorinated alkanes, hydrazine compounds (e.g., 4,4'-oxybis(benzenesulfonylhydrazide): OBSH), semicarbazide compounds, and triazole compounds. Another example is heat-expandable particles (unexpanded balloons) in which a heat-expandable substance (e.g., isobutane, butane, etc.) is encapsulated in microcapsules made of a thermoplastic resin (e.g., polyvinylidene chloride, polyacrylonitrile, poly(meth)acrylic acid ester, etc.).

[0054] The (F) foaming agent preferably contains at least one selected from the group consisting of an azo compound (for example, an ADCA-based chemical foaming agent), a hydrazine compound (for example, an OBSH-based chemical foaming agent), and an unexpanded balloon. When the (E) foaming agent contains at least one selected from the group consisting of an azo compound (e.g., an ADCA-based chemical foaming agent), a hydrazine compound (e.g., an OBSH-based chemical foaming agent), and an unexpanded balloon, the one-component curable composition according to the embodiment of the present invention can further improve the flexural strength and further reduce the distortion while obtaining a desired expansion ratio.

[0055] The one-component curable composition of the embodiment of the present invention may contain, for example, 0.01 to 5 parts by mass of the (F) foaming material per 100 parts by mass of the one-component curable composition, preferably 0.05 to 3 parts by mass of the (F) foaming material, more preferably 0.1 to 2 parts by mass of the (F) foaming material, and even more preferably 0.2 to 1 part by mass of the (E) foaming material. When the one-component curable composition according to the embodiment of the present invention contains 0.01 to 5 parts by mass of a foaming agent (E) per 100 parts by mass of the one-component curable composition, more appropriate foaming can be achieved, and more reinforcement can be ensured while further suppressing distortion.

[0056] The one-component curable composition according to the embodiment of the present invention may contain other components as appropriate, such as a conventional curing agent (excluding the above-mentioned latent curing agent), a diluent, a surfactant, and other additives.

[0057] In an embodiment of the present invention, the curing agent is a compound that does not have a curing action at room temperature but exhibits a curing action when heated to a certain temperature, and is not particularly limited as long as the one-component curable composition targeted by the present invention can be obtained, except for the above-mentioned latent curing agents.

[0058] In an embodiment of the present invention, the diluent is not particularly limited as long as it can impart fluidity to the one-component curable composition of an embodiment of the present invention and the one-component curable composition intended by the present invention can be obtained. Examples of diluents include hydrocarbon solvents such as paraffinic solvents, isoparaffinic solvents, naphthenic solvents, and aromatic solvents.

[0059] In an embodiment of the present invention, examples of other additives include moisture absorbents (calcium oxide, molecular sieves, etc.), thixotropic agents (organic bentonite, fumed silica, aluminum stearate, metallic soaps, castor oil derivatives, etc.), stabilizers (2,6-di-t-butyl-4-methylphenol, 2,2-methylene-bis(4-methyl-6-t-butylphenol), nickel dibutyldithiocarbamate, etc.), coupling agents such as silane or titanium, etc. The other additives can be used appropriately without any particular limitation, as long as the one-component curable composition intended by the present invention can be obtained.

[0060] The one-part curable composition of the present embodiment can be prepared by mixing the components described above. The mixing device and method are not particularly limited as long as they are capable of producing the one-component curable composition of the present invention. Specific examples of such mixing devices that can be used include a twin-screw mixer, a planetary mixer, a sigma mixer, a kneader, an attritor, a grain mill, a roll, and a dissolver. Furthermore, the mixing can be carried out using a container capable of mixing, for example, in a tank, a vessel, or the like.

[0061] The one-component curable composition of the embodiment of the present invention can be applied to a required location in any thickness and in any coating form using a known coating method, such as bead coating (round) or wide kishimen coating (strip) and can be cured by heating to a predetermined temperature using, for example, a hot air circulating drying oven. The one-component curable composition according to the embodiment of the present invention can be used as a coating-type one-component curable composition. In the above coating means, coating can be performed by a computer-controlled automatic coater or a robot coater.

[0062] In an embodiment of the present invention, a method for manufacturing an automobile can be provided, which includes using a one-part curable composition of an embodiment of the present invention. The curable composition of an embodiment of the present invention can be used in a production line for manufacturing automobiles to provide a reinforcing layer on automobile body sheet metal. That is, a reinforcing layer can be provided by applying the curable composition of an embodiment of the present invention to an automobile body sheet metal and then heat-curing it. Furthermore, a reinforced sheet metal structure in which a reinforcing layer is provided by applying the curable composition of an embodiment of the present invention to an automobile body sheet metal and then heat-curing it, and a method for manufacturing the same can be provided. Furthermore, it is possible to provide a one-component curable composition for reinforcing sheet metal that can be discharged by pumping.

[0063] The one-component curable composition of the present invention was subjected to a shear rate of 430 sec at 40°C. -1 The viscosity at 1000 kJ / min is preferably 50 to 300 Pa·s, more preferably 65 to 250 Pa·s, even more preferably 80 to 200 Pa·s, and even more preferably 90 to 180 Pa·s. The one-component curable composition of the present invention was subjected to a shear rate of 430 sec at 40°C. -1 When the viscosity at 2000 kJ / min is 50 to 300 Pa·s, the one-component curable composition according to the embodiment of the present invention can have improved pumpability.

[0064] The expansion ratio of the one-component curable composition according to the embodiment of the present invention is preferably 1.1 to 3 times, and more preferably 1.3 to 2.5 times. When the expansion ratio of the one-component curable composition according to the embodiment of the present invention is 1.1 to 3 times, the one-component curable composition according to the embodiment of the present invention can have further improved reinforcement and strain resistance.

[0065] The bending strength of the cured product of the one-component curable composition according to this embodiment of the present invention is preferably 18 N or more, more preferably 20 to 60 N, even more preferably 22 to 50 N, and even more preferably 24 to 40 N. When the bending strength of the cured product of the one-component curable composition of the embodiment of the present invention is 18 N or more, the one-component curable composition of the embodiment of the present invention can further improve the reinforcing properties.

[0066] The displacement (bending) of the cured product of the one-component curable composition according to an embodiment of the present invention is preferably 4.5 mm or more, more preferably 4.8 to 20 mm, even more preferably 5 to 17 mm, and even more preferably 5.5 to 15 mm. When the cured product of the one-component curable composition of the present invention is bent to a bending strength of 4.5 mm or more, the one-component curable composition of the present invention does not crack even when subjected to impact, and the reinforcing properties can be further ensured.

[0067] The cured product of the one-component curable composition according to the embodiment of the present invention preferably has a warpage of 2 mm or less, more preferably from −1 to 1.5 mm, even more preferably from −0.5 to 1.0 mm, and even more preferably from 0 to 0.5 mm. When the cured product of the one-component curable composition of the present invention has a warpage of 2 mm or less, the one-component curable composition of the present invention can further suppress distortion of the reinforcing panel.

[0068] The elastic modulus at 23°C of the cured product of the one-component curable composition of this embodiment of the present invention is preferably 100 to 1500 MPa, more preferably 200 to 1200 MPa, even more preferably 300 to 1000 MPa, and even more preferably 400 to 900 MPa. When the elastic modulus of the cured product of the one-component curable composition of the embodiment of the present invention is 100 to 1500 MPa, the one-component curable composition of the embodiment of the present invention is superior in strain resistance (warpage at room temperature and low temperature) and reinforcement (flexural strength).

[0069] The Tg of the cured product of the one-component curable composition according to the embodiment of the present invention, as measured by DMA, is preferably 95 to 180°C, more preferably 100 to 170°C, even more preferably 110 to 160°C, and even more preferably 120 to 150°C. When the Tg of the cured product of the one-component curable composition of the embodiment of the present invention is 95 to 180°C, the one-component curable composition of the embodiment of the present invention has better reinforcement properties at high temperatures. [Example]

[0070] EXAMPLES Hereinafter, the present invention will be specifically and in detail explained using examples and comparative examples, but these examples are merely one embodiment of the present invention, and the present invention is not limited to these examples in any way. In the examples, unless otherwise specified, parts by weight and percentages by weight are based on the parts not taking into account the solvent.

[0071] The components used in this example are listed below. (A) Epoxy resin (a1-1) Unmodified bisphenol A epoxy resin (JER828 (trade name) manufactured by Mitsubishi Chemical Corporation) (a3-1) Dimer acid diglycidyl ester (JER871 (trade name) manufactured by Mitsubishi Chemical Corporation) (a3-2) Polyoxyalkylene bisphenol A glycidyl ether (EP-4000 (trade name) manufactured by ADEKA Corporation)

[0072] (B) Elastomer (b1-1) Acrylonitrile-butadiene copolymer (N210S (product name) manufactured by JSR Corporation) (b1-2) Acrylonitrile-butadiene copolymer (DN-219 (trade name) manufactured by Nippon Zeon Co., Ltd.) (b1-3) Styrene-butadiene copolymer (Nipol 1502 (trade name) manufactured by Nippon Zeon Co., Ltd.) (b1-4) Partially crosslinked styrene-butadiene copolymer (EMULPRENE 1009 (trade name) manufactured by INDUSTRIAS NEGROMEX SADE CV) (b1-5) Methacrylic acid alkyl ester copolymer (LP-3106 (product name) manufactured by Mitsubishi Chemical Corporation)

[0073] (AB) Applies to both epoxy resins and elastomers (ab2-1) Unmodified bisphenol A epoxy resin containing polybutadiene-containing particles (Kaneka Ace MX-150 (trade name) manufactured by Kaneka Corporation) rubber particles: 40% by mass / bisphenol A epoxy resin: 60% by mass (ab2-2) Elastomer-modified epoxy resin (reaction product of 15% by mass of HyPox RA840 and 85% by mass of JER828 manufactured by Huntsman) 18% by mass of CTBN-modified epoxy resin / 82% by mass of unmodified bisphenol A-type epoxy resin (calculated values ​​at the time of synthesis) (b3-1) Methacrylic acid alkyl ester copolymer (LP-3106 (product name) manufactured by Mitsubishi Chemical Corporation)

[0074] (C) Plasticizer (c1) Diisononyl phthalate (Sanso Cizer DINP (trade name) manufactured by New Japan Chemical Co., Ltd.), the solubility parameter (SP value) of (c1) is 8.9 (J / cm 3 ) 1 / 2 is. (c2) Diisononyl adipate (Sanso Cizer DINA (trade name) manufactured by New Japan Chemical Co., Ltd.), the solubility parameter (SP value) of (c2) is 8.5 (J / cm 3 ) 1 / 2 is. (D) Latent hardener (d1) Dicyandiamide (CG1200 (trade name) manufactured by Air Products) (d2) 4,4'-methylenebis(phenyldimethylurea) (OMICURE U-52 (trade name) manufactured by PTI Japan)

[0075] (E) Filler (e1) Heavy calcium carbonate (Whiten B (product name) manufactured by Bihoku Kohoku Kogyo Co., Ltd.) (e2) Carbon black (Hiblack #20 (product name) manufactured by Asahi Carbon Co., Ltd.) (e3) U オ Lastnite needle filler (NYAD G (product name) manufactured by NYCO MINERALS), average particle diameter 40 μm (including lengths of 0.6 mm or more) (e4) U オ Lastnite needle filler (NYAD 325 (trade name) manufactured by NYCO MINERALS), average particle size 20 μm (F) Foaming agent (f1) Azodicarbonamide (AC-3M (trade name) manufactured by Eiwa Kasei Co., Ltd.) (G) Additives (g1) Calcium oxide (QC-X (product name) manufactured by Inoue Lime Industry Co., Ltd.)

[0076] These components were mixed in the parts by mass shown in Tables 1 and 2 to prepare one-component curable compositions of Examples 1 to 10 and Comparative Examples 1 to 4. The viscosity (40°C), shower resistance, foaming ratio, flexural strength (N), displacement at break (mm), warpage at low temperature (mm), modulus of elasticity at 23°C (MPa), and Tg (°C) of each of the above-mentioned curable compositions (or their cured products) were measured and evaluated by the following methods. The results are shown in Tables 1 and 2.

[0077] Viscosity measurement The viscosity of the curable composition was measured using a pressure-type apparent viscometer in accordance with JASO323-77. The curable composition was filled into the cylinder of the viscometer, and the temperature was adjusted to 40°C using a jacket or the like. It was confirmed that the temperature was 40°C. A No. 3 capillary (length: 74.1 mm, capillary diameter: 1.85 mm) was used. The shear rate was 430 s -1 The viscosity range in which the curable composition can be applied is considered to be 300 Pa·s or less, and the viscosity of the curable composition is preferably 50 Pa·s or more and 300 Pa·s or less.

[0078] Shower resistant A test specimen was prepared by applying the curable composition to a 200 × 300 × 0.8 mm SPCC-SD steel plate to a size of 150 × 200 × 1.8 mm. A water shower was applied to the surface of the test specimen coated with the curable composition at a temperature of 50°C, angle of 45°, and pressure of 490 kPa. The distance from the shower nozzle (Katori Seisakusho Co., Ltd., K9S type PT1 / 4 × 5.0) to the test specimen was 700 mm, and the shower was applied for 1 minute. After the shower, the coated surface was visually inspected to confirm the presence or absence of peeling or displacement of the curable composition. The evaluation criteria for shower resistance are as follows: ⊚: The curable composition is completely free from peeling and displacement. ◯: The curable composition is not peeled off or displaced. ◯△: The curable composition has very slight peeling or misalignment, but is not problematic. Δ: The curable composition is slightly peeled or displaced, but this does not pose a problem in practical use. Δ×: The curable composition is slightly peeled or displaced, which is problematic in practical use. ×: There is clear peeling or misalignment in the curable composition.

[0079] Foaming Ratio The curable composition was applied in a bead shape to a 3x7cm aluminum plate to prepare a test specimen. The test specimen was measured based on the underwater displacement method (see JASO323-77 Specific Gravity Test Method A), and the expansion ratio was calculated from the density (specific gravity) of the curable composition before and after curing. Expansion ratio (times) = (reciprocal of density after curing) ÷ reciprocal of density before curing The test specimen of the curable composition was placed in a forced circulation oven and cured for 25 minutes at 170° C. From the viewpoint of the reinforcement property and curing distortion of the cured product of the curable composition, the expansion ratio is preferably 1.1 to 3.0%, and more preferably 1.3 to 2.5%.

[0080] Bending strength (N) and displacement at break (mm) The curable composition was applied to a 25 x 200 x 0.8 mm SPCC-SD steel plate to a thickness of 1.8 mm, and the coated steel plate was placed in a forced circulation oven. The curable composition was cured at 170 ° C for 25 minutes to obtain a test specimen. A three-point bending test of this test specimen was performed using a bending strength tester specified in JIS K6911 under conditions of a support distance of 100 mm and a loading rate of 1 mm / min. The load (N / 25 mm) at 1 mm of displacement and the displacement at maximum load were determined to measure bending strength and flexural strength. Considering dent resistance in an actual vehicle, the load at 1 mm of displacement (flexural strength) is preferably 18 N or more, and the displacement (bending) at maximum load is preferably 4.5 mm or more.

[0081] Warpage at low temperature (mm) The curable composition was applied to a 25 x 200 x 0.8 mm SPCC-SD steel plate to a thickness of 1.8 mm, and the coated steel plate was then placed in a forced circulation oven, where the curable composition was cured at 170°C for 25 minutes to obtain a test specimen. A 1 kg·f weight was placed on one side of this test specimen, and the warpage height (mm) on the opposite side was measured in an environment of -40°C. Considering the amount of warpage that does not cause appearance defects in an actual vehicle, a warpage of 5 mm or less is preferable.

[0082] Elastic modulus at 23°C (MPa) and Tg (°C) The curable composition was applied to a 0.8 mm aluminum plate treated with a release agent such as Teflon® to a thickness of 1 to 2 mm after curing. The coated test specimen was then placed in a forced-circulation oven, and the curable composition was cured at 170°C for 25 minutes to obtain a cured product. The cured product was cut to a width of 5 mm and a length of 50 mm, and the modulus of elasticity and tan δ were measured using a dynamic mechanical analysis (DMA) device at a heating rate of 2°C / min over a range from -50 to 150°C. The temperature at which the modulus of elasticity and tan δ peaked at 23°C were recorded as Tg. Considering dent resistance in an actual vehicle and the operating temperature environment, it is preferable for the product to satisfy both a modulus of elasticity of 100 to 1500 MPa and a Tg of 95 to 180°C.

[0083] [Table 1]

[0084] [Table 2]

[0085] The curable compositions of Examples 1 to 10 and their cured products can be used as pumpable one-component curable compositions for sheet metal reinforcement, which can further improve strain resistance and reinforcement while ensuring pumpability and shower resistance.

[0086] The curable compositions and cured products thereof of Comparative Examples 1 to 6 were unable to improve strain resistance and reinforcement while ensuring pumpability and shower resistance, and therefore could not be said to be sufficient as one-component curable compositions for application. [Industrial Applicability]

[0087] The one-component curable composition according to the embodiment of the present invention can further improve strain resistance and reinforcement while ensuring pumpability and shower resistance. Furthermore, the one-component curable composition can be suitably applied to sheet metal and can be suitably used as a spreadable sheet metal reinforcing material.

Claims

1. A one-component curable composition comprising (A) an epoxy resin, (B) an elastomer, (C) a plasticizer, (D) a latent curing agent, (E) a filler, and (F) a foaming agent, The epoxy resin (A) contains at least an unmodified epoxy resin (A1) having a cyclic structure, The elastic modulus of the cured product at 23°C is 100 to 1500 MPa, The glass transition temperature of the cured product measured by dynamic viscoelasticity measurement is 95 to 180°C. A pumpable, one-part curable composition for reinforcing sheet metal.

2. (B) The elastomer is a diene-based solid rubber (B1). The one-component curable composition according to claim 1 , further comprising (B2) a fine particle or liquid reactive elastomer.

3. 2. The one-component curable composition according to claim 1, wherein the epoxy resin (A) comprises 35 to 85 parts by mass of an unmodified epoxy resin (A1) having a cyclic structure, relative to 100 parts by mass of the total of (A), (B), and (D).

4. 2. The one-component curable composition according to claim 1, wherein the unmodified epoxy resin (A1) having a cyclic structure comprises a bisphenol A epoxy resin, and the one-component curable composition contains 50 to 100 parts by mass of the unmodified epoxy resin (A1) having a cyclic structure per 100 parts by mass of the epoxy resin (A).

5. 2. The one-component curable composition according to claim 1, wherein the filler (E) comprises a needle-shaped filler, and the content of the needle-shaped filler is 30 to 50 mass% relative to 100 mass% of the entire composition.

6. 2. The one-component curable composition according to claim 1, wherein the blowing agent (F) comprises at least one selected from the group consisting of an azo compound, a hydrazine compound, and a thermally expandable particle, and the one-component curable composition has an expansion ratio of 1.1 to 3 times.

7. Shear rate 430 sec at 40°C －１ 2. The one-component curable composition according to claim 1, wherein the viscosity at 1000 kJ / min is 50 to 300 Pa·s.

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