Thermosetting resin composition for pipe lining material and cured product thereof

Abstract

The present invention provides a thermosetting resin composition, for a pipe lining material, that contains a resin component (A) having as essential components a maleic acid-modified epoxy (meth)acrylate (A1) and an unsaturated monomer (A2), a thermally-decomposable curing agent (B), and a curing accelerator (C), said thermosetting resin composition being characterized in that the maleic acid-modified epoxy (meth)acrylate (A1) is a reaction product of a hydroxyl group of an epoxy (meth)acrylate (a1) and a carboxyl group of maleic acid (anhydride). This thermosetting resin composition for a pipe lining material has a long pot life, is excellent in fast curing properties and thixotropy, and can provide a pipe lining material cured product that has excellent bending strength, tensile elongation, and heat resistance. Therefore, this thermosetting resin composition for a pipe lining material can be suitably used for the rehabilitation of sewer pipes, water pipes, gas pipes, electric power tubes, and the like.　

Description

Thermosetting resin composition for pipe lining material and cured product thereof

[0001] The present invention relates to a thermosetting resin composition for pipe lining materials and a cured product thereof.

[0002] BACKGROUND ART A thermosetting rehabilitation method using a lining material containing a styrene-based unsaturated polyester resin composition and a vinyl ester resin composition is widely used as a method for repairing deteriorated pipes such as those in sewerage systems.

[0003] In light of this, a pipeline rehabilitation method has been proposed that includes a lining material introduction step and a curing step to form a rehabilitated pipe (see, for example, Patent Document 1). However, this rehabilitation method using a vinyl ester resin has problems in that it is difficult to achieve both rapid curing and a long usable life for the lining material, and the thixotropy is insufficient, which affects workability.

[0004] JP 2018-30280 A

[0005] The problem to be solved by the present invention is to provide a resin composition for a pipe lining material that has a long pot life, is fast-curing, has excellent workability (thixotropy), and can give a cured pipe lining material that is excellent in flexural strength, tensile elongation, and heat resistance.

[0006] The present inventors have discovered that the above-mentioned problems can be solved by a thermosetting resin composition for pipe lining materials, which contains a resin component having as essential components a specific maleic acid-modified epoxy (meth)acrylate and an unsaturated monomer, a thixotropic agent, a thermally decomposable curing agent, and a curing accelerator, and have completed the present invention.

[0007] That is, the present invention relates to a thermosetting resin composition for pipe lining materials, which contains a resin component (A) having as essential components a maleic acid-modified epoxy (meth)acrylate (A1) and an unsaturated monomer (A2), a thermally decomposable curing agent (B), and a curing accelerator (C), wherein the maleic acid-modified epoxy (meth)acrylate (A1) is a reaction product of a hydroxyl group of the epoxy (meth)acrylate (a1) and a carboxyl group of maleic acid (anhydride).

[0008] The pipe lining material obtained from the thermosetting resin composition for pipe lining material of the present invention has a long pot life, is fast-curing, and has excellent thixotropy, and can provide a cured pipe lining material that is excellent in bending strength, tensile elongation, and heat resistance. Therefore, the pipe lining material can be suitably used for the rehabilitation of sewer pipes, water pipes, gas pipes, electric power pipes, etc.

[0009] The thermosetting resin composition for pipe lining materials of the present invention is a thermosetting resin composition for pipe lining materials containing a resin component (A) having as essential components a maleic acid-modified epoxy (meth)acrylate (A1) and an unsaturated monomer (A2), a thermally decomposable curing agent (B), and a curing accelerator (C), wherein the maleic acid-modified epoxy (meth)acrylate (A1) is a reaction product of a hydroxyl group of the epoxy (meth)acrylate (a1) and a carboxyl group of maleic acid (anhydride).

[0010] In the present invention, "(meth)acrylate" refers to either or both of acrylate and methacrylate, "(meth)acrylic acid" refers to either or both of acrylic acid and methacrylic acid, and "(meth)maleic anhydride" refers to either or both of maleic acid and maleic anhydride.

[0011] The epoxy (meth)acrylate (a1) is obtained, for example, by reacting an epoxy resin with (meth)acrylic acid, and has no epoxy group but has a (meth)acryloyl group and a hydroxyl group.

[0012] Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol fluorene type epoxy resins, and biscresol fluorene type epoxy resins; novolac type epoxy resins such as phenol novolac type epoxy resins and cresol novolac type epoxy resins; oxazolidone-modified epoxy resins; brominated epoxy resins of these resins; glycidyl ethers of phenols such as dipropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ethers of alkylene oxide adducts of bisphenol A, and diglycidyl ethers of hydrogenated bisphenol A; 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate; Examples of epoxy resins include alicyclic epoxy resins such as 3,4-epoxycyclohexane, glycidyl esters such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl-p-oxybenzoate, and dimer acid glycidyl ester, glycidyl amines such as tetraglycidyldiaminodiphenylmethane, tetraglycidyl-m-xylenediamine, triglycidyl-p-aminophenol, and N,N-diglycidylaniline, and heterocyclic epoxy resins such as 1,3-diglycidyl-5,5-dimethylhydantoin and triglycidyl isocyanurate. Among these, bifunctional aromatic epoxy resins are preferred, with bisphenol A epoxy resins and bisphenol F epoxy resins being more preferred, as they provide superior rehabilitating pipe strength, ease of handling of the lining material, and fluidity during production of the lining material. These epoxy resins can be used alone or in combination of two or more.

[0013] The epoxy equivalent of the epoxy resin is preferably 180 to 420 g / eq, more preferably 180 to 250 g / eq, because this provides better rehabilitated pipe strength, easier handling of the lining material, and better fluidity during production of the lining material.

[0014] The reaction between the epoxy resin and (meth)acrylic acid is preferably carried out using an esterification catalyst at a temperature of 60 to 140° C. A polymerization inhibitor or the like may also be used.

[0015] The maleic acid-modified epoxy (meth)acrylate (A1) is obtained by an ester reaction between a hydroxyl group of the epoxy (meth)acrylate (a1) and a carboxyl group of maleic acid (anhydride). In order to further improve the balance between the usable time and fast curing property required for rehabilitating pipes, the molar ratio (OH / COOH) of the hydroxyl group (OH) of the epoxy (meth)acrylate (a1) to the carboxyl group (COOH) of the maleic acid (anhydride) is preferably 100 / 5 to 100 / 75, more preferably 100 / 10 to 100 / 50.

[0016] The maleic acid-modified epoxy (meth)acrylate (A1) is preferably one in which 5 to 75% of the hydroxyl groups of the epoxy (meth)acrylate (a1) are esterified, and more preferably one in which 10 to 50% are esterified.

[0017] The acid value of the maleic acid-modified epoxy (meth)acrylate (A1) is preferably 10 to 70 mgKOH / g, more preferably 20 to 60 mgKOH / g, because this further improves the balance between the usable time and fast curing property required for rehabilitating pipes.

[0018] Examples of the unsaturated monomer (A2) include monofunctional (meth)acrylate compounds such as benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate alkyl ether, polypropylene glycol (meth)acrylate alkyl ether, 2-ethylhexyl methacrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, isotridecyl (meth)acrylate, n-stearyl (meth)acrylate, tetrahydrofurfuryl methacrylate, isobornyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl methacrylate, and methacrylic (meth)acrylate; ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate. Examples of suitable unsaturated monomers include di(meth)acrylate compounds such as 1,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol di(meth)acrylate, and 1,4-cyclohexanedimethanol di(meth)acrylate; tri(meth)acrylates such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate; polyfunctional (meth)acrylate compounds such as pentaerythritol tetra(meth)acrylate and dipentaerythritol hexa(meth)acrylate; styrene, α-methylstyrene, vinyltoluene, diallyl phthalate, and divinylbenzene. Among these, unsaturated monomers having an aromatic group are preferred, and styrene, phenoxyethyl (meth)acrylate, and benzyl (meth)acrylate are more preferred, as they allow for the production of molded articles with higher strength. These unsaturated monomers (A2) can be used alone or in combination of two or more.

[0019] The mass ratio (A1 / A2) of the maleic acid-modified epoxy (meth)acrylate (A1) to the unsaturated monomer (A2) is preferably 25 / 75 to 75 / 25, more preferably 30 / 70 to 70 / 30, because this further improves the strength of the rehabilitated pipe, the handleability of the lining material, and the fluidity during production of the lining material.

[0020] The resin component (A) contains the maleic acid-modified epoxy (meth)acrylate (A1) and the unsaturated monomer (A2) as essential components, but may also contain other resin components.

[0021] The thermally decomposable curing agent (B) is not particularly limited, but is preferably an organic peroxide, for example, ketone peroxides such as methyl ethyl ketone peroxide and acetyl lactone peroxide; hydroperoxides such as cumene hydroperoxide and t-butyl hydroperoxide; diacyl peroxides such as dilauryl peroxide and dibenzyl peroxide; dialkyl peroxides such as dicumyl peroxide and dibutyl peroxide; peroxyketals such as 1,1-di(t-butylperoxy)cyclohexylane and 2,2-di(t-amylperoxy)butane; alkyl peresters such as cumyl peroxy neodecanate and t-butylperoxy 2-ethylhexanate; and percarbonates such as di(4-t-butylcyclohexyl)peroxydicarbonate and t-butylperoxyisopropyl carbonate, and the like, which can be appropriately selected depending on the curing conditions. These thermally decomposable curing agents (B) can be used alone or in combination of two or more.

[0022] Among these, thermally decomposable curing agents having a temperature of 40° C. or higher and 130° C. or lower for achieving a 10-hour half-life are preferred, as they have a better balance between usable time and rapid curing properties.

[0023] The content of the thermally decomposable curing agent (B) is preferably 0.3 to 3% by mass relative to the resin component (A) in order to obtain a better balance between the usable time and the rapid curing property.

[0024] The curing accelerator (C) is a substance that decomposes the thermally decomposable curing agent (C) by a redox reaction, facilitating the generation of active radicals, and examples thereof include organic cobalt salts such as cobalt naphthenate and cobalt octylate, metal soaps such as zinc octylate, vanadium octylate, copper naphthenate and barium naphthenate, metal chelates such as vanadium acetylacetate, cobalt acetylacetate and iron acetylacetonate, aniline, N,N-dimethylaniline, N,N-diethylaniline, p-toluidine, N,N-dimethyl-p-toluidine, ethylene oxide adduct of N,N-dimethyl-p-toluidine, N,N-bis(2-hydroxyethyl)-p-toluidine, and the like. Examples of curing accelerators include N,N-substituted anilines such as luidine, 4-(N,N-dimethylamino)benzaldehyde, 4-[N,N-bis(2-hydroxyethyl)amino]benzaldehyde, 4-(N-methyl-N-hydroxyethylamino)benzaldehyde, N,N-bis(2-hydroxypropyl)-p-toluidine, N-ethyl-m-toluidine, triethanolamine, m-toluidine, diethylenetriamine, pyridine, phenylmorpholine, piperidine, N,N-bis(hydroxyethyl)aniline, and diethanolaniline; and amine compounds such as N,N-substituted-p-toluidine and 4-(N,N-substituted amino)benzaldehyde, with cobalt organic acid salts being preferred. These curing accelerators can be used alone or in combination of two or more.

[0025] The content of the curing accelerator (C) is preferably 0.1 to 3% by mass relative to the resin component (A) in order to achieve a better balance between the usable time and the rapid curing property.

[0026] The thermosetting resin composition for pipe lining materials of the present invention contains a resin component (A), a thermally decomposable curing agent (B), and a curing accelerator (C), and may contain other additives as needed.

[0027] Examples of the other additives include a thixotropic agent, a polymerization inhibitor, an antioxidant, a light stabilizer, a solvent, an antifoaming agent, a leveling agent, a tackifier, an antistatic agent, a flame retardant, a pigment, a filler, a reinforcing material, and an aggregate.

[0028] The thermosetting resin composition for pipe lining materials of the present invention preferably contains a thixotropic agent, as this further improves the thixotropic properties. The thixotropic agent is not particularly limited as long as it can impart thixotropy to the resin composition. Examples of the thixotropic agent include silica powder such as fumed silica, asbestos, smectite, and calcium sulfate whiskers. Commercially available fumed silica products include the Reolosil QS series (manufactured by Tokuyama Corporation), the Aerosil series (manufactured by Nippon Aerosil Co., Ltd.), the CABOSIL series (manufactured by CABOT), and the HDK series (manufactured by WACKER). These thixotropic agents can be used alone or in combination. Furthermore, compounds having polar groups, such as water, glycol, and polyethylene glycol, can also be used as thixotropic assistants to further strengthen the hydrogen bonds of the thixotropic agent.

[0029] The amount of the thixotropic agent used is preferably 0.1 to 5 parts by mass per 100 parts by mass of the resin component (A) from the viewpoint of the balance between thixotropy and moldability.

[0030] The thermosetting resin composition for pipe lining materials of the present invention can be easily obtained by mixing the resin component (A), the thermally decomposable curing agent (B), the curing accelerator (C), and, if necessary, other additives.

[0031] A preferred method for obtaining a cured product from the thermosetting resin composition for pipe lining materials of the present invention is, for example, to perform pre-curing by heat curing at 50 to 100°C for 0.5 to 4 hours, and post-curing by heat curing at 80 to 130°C for 0.5 to 4 hours.

[0032] The thermosetting resin composition for pipe lining materials of the present invention has a long pot life, is fast-curing, and is excellent in workability, and the resulting cured product has excellent flexural strength, tensile elongation, and heat resistance, and therefore can be used as a pipe lining material.

[0033] Examples of pipe rehabilitation methods using the thermosetting resin composition for pipe lining of the present invention include the following. First, a tubular body is prepared, having a flexible film layer on the outside that matches the entire inside diameter of the existing pipe and a fiber-reinforced material on the inside. Next, the interior of the tubular body is depressurized to remove air, and the tubular body is gradually impregnated from one end along its entire length with the thermosetting resin composition of the present invention to obtain a pipe lining material. This pipe lining material is transported to the insertion opening of the existing pipe while maintained in a frozen or refrigerated state, and is inverted while adhering to the existing pipe using fluid pressure such as air or water pressure. It is then cured while adhering to the existing pipe using hot air, hot steam, warm water, or the like. Finally, excess pipe lining material is cut off from the end of the applied pipe lining material at the stop and insertion sections, and the lined pipe is inserted to complete the process.

[0034] The present invention will be described in more detail below with reference to specific examples, in which the acid value and epoxy equivalent were measured in accordance with JIS-K-6901 and JIS-K-7236, respectively.

[0035] Synthesis Example 1: Synthesis of Maleic Acid-Modified Epoxy (Meth)acrylate (A1-1) A 2-L flask equipped with a thermometer, nitrogen inlet tube, and stirrer was charged with 455 parts by mass of bisphenol A-type epoxy resin (DIC Corporation's "Epiclon 850," epoxy equivalent: 187), 201 parts by mass of methacrylic acid, and 0.23 parts by mass of dibutylhydroxytoluene under a gas flow atmosphere of a 1:1 mixture of nitrogen and air. The mixture was heated to 90°C and reacted for 1 hour, after which 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was added, and the reaction temperature was raised to 100°C and reacted for 2 hours. Thereafter, 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was further added, and the acid value and epoxy equivalent were measured. It was confirmed that the acid value was 7.0 mgKOH / g or less and the epoxy equivalent was 5,000 g / eq or more, yielding epoxy (meth)acrylate (a1-1). To this mixture, 58.9 parts by mass of maleic anhydride was added, the reaction temperature was raised to 90°C, and the reaction was terminated after 5 hours. 0.11 parts by mass of methylhydroquinone, 0.11 parts by mass of tertiary butylcatechol, and 383 parts by mass of styrene were added and dissolved, and the mixture was cooled to around 40°C, yielding a resin solution of maleic acid-modified epoxy (meth)acrylate (A1-1). The molar ratio (OH / COOH) was 100 / 25, and 25% of the hydroxyl groups in the epoxy (meth)acrylate (a1-1) were esterified. The acid value of the maleic acid-modified epoxy (meth)acrylate (A1-1) was 31.1 mgKOH / g.

[0036] Synthesis Example 2: Synthesis of Maleic Acid-Modified Epoxy(meth)acrylate (A1-2) A 2-L flask equipped with a thermometer, nitrogen inlet tube, and stirrer was charged with 455 parts by mass of bisphenol A-type epoxy resin (DIC Corporation's "Epiclon 850," epoxy equivalent: 187), 201 parts by mass of methacrylic acid, and 0.23 parts by mass of dibutylhydroxytoluene under a gas flow atmosphere of a 1:1 mixture of nitrogen and air. The mixture was heated to 90°C and reacted for 1 hour, after which 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was added, and the reaction temperature was raised to 100°C and reacted for 2 hours. Thereafter, 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was further added, and the acid value and epoxy equivalent were measured. It was confirmed that the acid value was 7.0 or less and the epoxy equivalent was 5,000 or more, yielding epoxy(meth)acrylate (a1-2). To this mixture, 118 parts by mass of maleic anhydride was added, the reaction temperature was raised to 90°C, and the reaction was terminated after 5 hours. 0.12 parts by mass of methylhydroquinone, 0.12 parts by mass of tertiary butylcatechol, and 414 parts by mass of styrene were added and dissolved, and the mixture was cooled to around 40°C, yielding a resin solution of maleic acid-modified epoxy (meth)acrylate (A1-2). The molar ratio (OH / COOH) was 100 / 50, and 50% of the hydroxyl groups in the epoxy (meth)acrylate (a1-2) were esterified. The acid value of the maleic acid-modified epoxy (meth)acrylate (A1-2) was 54.2 mgKOH / g.

[0037] Synthesis Example 3: Synthesis of Maleic Acid-Modified Epoxy(meth)acrylate (A1-3) A 2-L flask equipped with a thermometer, nitrogen inlet tube, and stirrer was charged with 315 parts by mass of bisphenol A-type epoxy resin (DIC Corporation's "Epiclon 850," epoxy equivalent: 187), 139 parts by mass of methacrylic acid, and 0.16 parts by mass of dibutylhydroxytoluene under a gas flow atmosphere of a 1:1 mixture of nitrogen and air. The mixture was heated to 90°C and reacted for 1 hour, after which 0.45 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was added, and the reaction temperature was raised to 100°C and reacted for 2 hours. Thereafter, an additional 0.45 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was added, and the acid value and epoxy equivalent were measured. It was confirmed that the acid value was 7.0 or less and the epoxy equivalent was 5,000 or more, yielding epoxy(meth)acrylate (a1-3). To this mixture, 48.9 parts by mass of maleic anhydride was added, the reaction temperature was raised to 90°C, and the reaction was terminated after 5 hours. 0.10 parts by mass of methyl hydroquinone, 0.10 parts by mass of tertiary butyl catechol, 0.30 parts by mass of dibutylhydroxytoluene, 254 parts by mass of phenoxyethyl methacrylate, and 361 parts by mass of diethylene glycol dimethacrylate were added and dissolved, and the mixture was cooled to around 40°C to obtain a resin solution of maleic acid-modified epoxy (meth)acrylate (A1-3). The molar ratio (OH / COOH) was 100 / 30, and 30% of the hydroxyl groups in the epoxy (meth)acrylate (a1-3) were esterified. The acid value of the maleic acid-modified epoxy (meth)acrylate (A1-3) was 28.4 mgKOH / g.

[0038] Synthesis Example 4: Synthesis of Epoxy (Meth)acrylate (a1-4) A 2-L flask equipped with a thermometer, nitrogen inlet tube, and stirrer was charged with 455 parts by mass of bisphenol A-type epoxy resin (DIC Corporation's "Epiclon 850," epoxy equivalent: 187), 201 parts by mass of methacrylic acid, and 0.23 parts by mass of dibutylhydroxytoluene under a gas flow atmosphere of a 1:1 mixture of nitrogen and air. The mixture was heated to 90°C and reacted for 1 hour, after which 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was added, and the reaction temperature was raised to 100°C and reacted for 2 hours. Thereafter, an additional 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was added, and the acid value and epoxy equivalent were measured. After confirming that the acid value was 7.0 or less and the epoxy equivalent was 5,000 or more, the reaction was terminated. 0.10 parts by mass of methylhydroquinone, 0.10 parts by mass of tertiary butylcatechol, and 353 parts by mass of styrene were added and dissolved, and the mixture was cooled to around 40° C. to obtain a resin solution of epoxy (meth)acrylate (a1-4). The acid value of the epoxy (meth)acrylate (a1-4) was 1.0 mgKOH / g.

[0039] Example 1: Production of thermosetting resin composition (1) for pipe lining material 100 parts by mass of the resin solution of maleic acid-modified epoxy (meth)acrylate obtained in Synthesis Example 1, 1.0 part by mass of fumed silica ("Aerogel #200" manufactured by Nippon Aerosil Co., Ltd.), and 0.2 part by mass of polyethylene glycol ("PEG #400" manufactured by NOF Corporation) were mixed and stirred with a Disper mixer. Next, 0.2 parts by mass of 6% cobalt octylate ("Accelerator RP-330" manufactured by DIC Materials Corporation) as a curing accelerator, 0.5 parts by mass of a polymerization initiator ("Perloyl TCP" manufactured by NOF Corporation), and 1.0 part by mass of a polymerization initiator ("Percure HO(N)" manufactured by NOF Corporation) were uniformly blended to obtain a thermosetting resin composition (1) for pipe lining material.

[0040] (Examples 2 and 3: Production of thermosetting resin compositions (2) and (3) for pipe lining materials) Thermosetting resin compositions (2) and (3) for pipe lining materials were obtained in the same manner as in Example 1, except that the resin solution of the maleic acid-modified epoxy (meth)acrylate (A1-1) used in Example 1 was changed to the resin solution of the maleic acid-modified epoxy (meth)acrylate (A1-2) or (A1-3) obtained in Synthesis Example 2 or 3.

[0041] Comparative Example 1: Production of thermosetting resin composition (R1) for pipe lining material A thermosetting resin composition (R1) for pipe lining material was obtained in the same manner as in Example 1, except that the resin solution of the maleic acid-modified epoxy (meth)acrylate (A1-1) used in Example 1 was changed to the resin solution of the epoxy (meth)acrylate (a1-4) obtained in Synthesis Example 4.

[0042] [Evaluation of workability (thixotropy)] The viscosity of the thermosetting resin composition for pipe lining material obtained above was measured at 25°C using a Brookfield viscometer (BF rotational viscometer, manufactured by Toki Sangyo Co., Ltd.) in accordance with JIS K 6901, and the thixotropy (6 rpm viscosity / 60 rpm viscosity) was determined, and the workability was evaluated according to the following criteria: ◯: thixotropy is 2.0 or more ×: thixotropy is less than 2.0

[0043] [Evaluation of pot life] 70 g of the thermosetting resin composition for pipe lining material obtained above was placed in a 70 ml bottle and stored at 20°C. The time until gelling occurred was measured and the pot life was evaluated according to the following criteria: ◯: Time until gelling occurred was 90 hours or more ×: Time until gelling occurred was less than 90 hours

[0044] [Evaluation of Rapid Curing Property] The gelation time of the thermosetting resin compositions for pipe lining materials obtained above was measured at 80°C in accordance with JIS K 6901, and the rapid curing property was evaluated according to the following criteria: ◯: Gelling time was less than 3 minutes; ×: Gelling time was 3 minutes or more.

[0045] [Evaluation of Physical Properties of Cured Product] The thermosetting resin composition for pipe lining material obtained above was subjected to vacuum degassing, and then cast into a mold using two glass plates whose inner surfaces had been treated with a release agent, sealing the entire surface except for the upper edge with a 3 mm thick silicone rubber packing. The molded product was then cured in a dryer at 50°C for 4 hours and then post-cured in a dryer at 120°C for 2 hours to prepare a cast plate, and various physical properties were measured.

[0046] [Flexural strength] The flexural strength of the cast plate obtained above was measured in accordance with JIS K7171-1 and evaluated according to the following criteria. ○: 100 MPa or more ×: less than 100 MPa [Tensile elongation] The cast plate obtained above was subjected to a tensile test on a 1B test piece in accordance with JIS K7161-1 and 2 to measure the tensile elongation and evaluate it according to the following criteria. ○: 2.0% or more ×: less than 2.0% [Heat resistance] The deflection temperature under load of the cured product obtained above was measured in accordance with JIS K7191-1 and evaluated according to the following criteria. ○: 85°C or more ×: less than 85°C

[0047] The evaluation results of the thermosetting resin compositions for pipe lining materials (1) to (3) and (R1) obtained above are shown in Table 1.

[0048]

[0049] It was confirmed that the thermosetting resin compositions for pipe lining materials of the present invention in Examples 1 to 3 had a long pot life, were excellent in fast curing properties and workability, and the resulting cured products had excellent flexural strength, tensile elongation and heat resistance.

[0050] On the other hand, Comparative Example 1 is an example in which a non-maleic acid-modified epoxy (meth)acrylate was used instead of the maleic acid-modified epoxy (meth)acrylate (A1), and it was confirmed that the rapid curing property, workability, and usable life were insufficient.

Claims

1. A method for producing a cured product of a thermosetting resin composition for a pipe lining material, the composition containing a resin component (A) having maleic acid-modified epoxy (meth)acrylate (A1) and an unsaturated monomer (A2) as essential components, a thermal decomposition type curing agent (B), and a curing accelerator (C), wherein the maleic acid-modified epoxy (meth)acrylate (A1) is a reaction product of a hydroxyl group of epoxy (meth)acrylate (a1) and a carboxyl group of (anhydrous) maleic acid, the unsaturated monomer (A2) has an aromatic ring, and the method includes a step of heating and curing the thermosetting resin composition for a pipe lining material at 50 to 100°C.

2. The method for producing a cured product of a thermosetting resin composition for a pipe lining material according to Claim 1, wherein 5 to 75 mol% of the hydroxyl groups of the epoxy (meth)acrylate (a1) in the maleic acid-modified epoxy (meth)acrylate (A) are esterified.

3. The method for producing a cured product of a thermosetting resin composition for a pipe lining material according to Claim 1, wherein the mass ratio (A1 / A2) of the maleic acid-modified epoxy (meth)acrylate (A1) to the unsaturated monomer (A2) is 25 / 75 to 75 / 25.