JP7768455B2 - Thermosetting resin composition for pipe lining material and cured product thereof - Google Patents

Description

The present invention relates to a thermosetting resin composition for pipe lining materials and its cured product.

A thermosetting rehabilitation method using lining materials made from styrene-based unsaturated polyester resin compositions and vinyl ester resin compositions is widely used to repair aging pipes in sewers and other systems.

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

JP 2018-30280 A

The problem that this invention aims to solve is to provide a resin composition for pipe lining materials that has a long pot life, is fast-curing, has excellent workability (thixotropy), and can produce cured pipe lining materials that have excellent flexural strength, tensile elongation, and heat resistance.

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.

That is, the present invention relates to a thermosetting resin composition for pipe lining materials, which contains a resin component (A) essentially consisting of 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 in the epoxy (meth)acrylate (a1) and a carboxyl group in maleic acid (anhydride).

The pipe lining material obtained from the thermosetting resin composition for pipe lining of the present invention has a long pot life, is fast-curing, has excellent thixotropy, and produces a cured pipe lining material with excellent bending strength, tensile elongation, and heat resistance, making it suitable for use in pipe rehabilitation such as sewer pipes, water pipes, gas pipes, and electric power pipes.

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) essentially comprising 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).

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 "(anhydride)maleic acid" refers to either or both of maleic acid and maleic anhydride.

The epoxy (meth)acrylate (a1) is obtained, for example, by reacting an epoxy resin with (meth)acrylic acid, and does not have an epoxy group but has a (meth)acryloyl group and a hydroxyl group.

Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol fluorene type epoxy resin, and biscresol fluorene type epoxy resin; novolac type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; oxazolidone-modified epoxy resin; brominated epoxy resins of these resins; glycidyl ethers of phenols such as dipropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of alkylene oxide adduct of bisphenol A, and glycidyl ether of polyhydric alcohols such as diglycidyl ether of hydrogenated bisphenol A; 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate; 1-ethoxy-2-methyl-2-methyl-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.

The epoxy equivalent of the epoxy resin is preferably 180 to 420 g/eq, more preferably 180 to 250 g/eq, as this improves the strength of the rehabilitated pipe, the handleability of the lining material, and the fluidity during the production of the lining material.

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 may also be used.

The maleic acid-modified epoxy (meth)acrylate (A1) is obtained by an ester reaction between the hydroxyl groups of the epoxy (meth)acrylate (a1) and the carboxyl groups of maleic acid (anhydride). Because this improves the balance between the usable time and rapid curing properties required for rehabilitating pipes, the molar ratio (OH/COOH) of the hydroxyl groups (OH) of the epoxy (meth)acrylate (a1) to the carboxyl groups (COOH) of the maleic acid (anhydride) is preferably 100/5 to 100/75, and more preferably 100/10 to 100/50.

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.

The acid value of the maleic acid-modified epoxy (meth)acrylate (A1) is preferably 10 to 70 mg KOH/g, more preferably 20 to 60 mg KOH/g, as this improves the balance between the usable time and rapid curing properties required for rehabilitating pipes.

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.

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, as this further improves the strength of the rehabilitated pipe, the handleability of the lining material, and the fluidity during production of the lining material.

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.

The thermally decomposable curing agent (B) is not particularly limited, but is preferably an organic peroxide. Examples thereof include 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)cyclohexane 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 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.

Among these, thermal decomposition curing agents with a temperature of 40°C or higher and 130°C or lower to achieve a 10-hour half-life are preferred, as they offer a better balance between usable time and rapid curing.

The content of the thermally decomposable curing agent (B) is preferably 0.3 to 3 mass% relative to the resin component (A), as this provides a better balance between usable time and rapid curing.

The curing accelerator (C) is a substance that decomposes the thermally decomposable curing agent (C) through a redox reaction, facilitating the generation of active radicals. Examples include organic cobalt salts such as cobalt naphthenate and cobalt octoate, metal soaps such as zinc octoate, vanadium octoate, 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, and N,N-bis(2-hydroxyethyl)-p-toluidine. 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.

The content of the curing accelerator (C) is preferably 0.1 to 3 mass% relative to the resin component (A), as this provides a better balance between usable time and rapid curing.

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

Examples of such other additives include thixotropic agents, polymerization inhibitors, antioxidants, light stabilizers, solvents, defoamers, leveling agents, tackifiers, antistatic agents, flame retardants, pigments, fillers, reinforcing materials, and aggregates.

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 include silica powders such as fumed silica, asbestos, smectite, and calcium sulfate whiskers. Commercially available fumed silica products include the Reolosil QS series (Tokuyama Corporation), the Aerosil series (Nippon Aerosil Co., Ltd.), the CABOSIL series (CABOT Corporation), and the HDK series (WACKER). These thixotropic agents can be used alone or in combination. Furthermore, compounds with 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.

From the viewpoint of the balance between thixotropy and moldability, 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).

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 other additives as necessary.

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 pre-cure by heating and curing at 50 to 100°C for 0.5 to 4 hours, and then post-cure by heating and curing at 80 to 130°C for 0.5 to 4 hours.

The thermosetting resin composition for pipe lining materials of the present invention has a long pot life, rapid curing properties, and excellent workability, and the resulting cured product has excellent flexural strength, tensile elongation, and heat resistance, making it suitable for use as a pipe lining material.

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 length of the inner 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 thermosetting resin composition of the present invention is gradually impregnated into the tubular body from one end along its entire length to obtain the 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 and the insertion section, and the lined pipe is inserted to complete the process.

The present invention will be explained in more detail below with reference to specific examples. The acid value was measured in accordance with JIS-K-6901, and the epoxy equivalent was measured in accordance with JIS-K-7236.

(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 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. An additional 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was then 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.

(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 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. An additional 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was then 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, and the reaction temperature was raised to 90°C. After 5 hours, the reaction was terminated. 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 to obtain 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.

(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 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. An additional 0.45 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was then 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, and the reaction temperature was raised to 90°C. After 5 hours, the reaction was terminated. 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.

(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 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. An additional 0.66 parts by mass of 2,4,6-tris(dimethylaminomethyl)phenol was then added, and the acid value and epoxy equivalent were measured. The reaction was terminated after confirming that the acid value was 7.0 or less and the epoxy equivalent was 5,000 or more. 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.

(Example 1: Production of thermosetting resin composition (1) for pipe lining material)
100 parts by mass of the maleic acid-modified epoxy (meth)acrylate resin solution obtained in Synthesis Example 1, 1.0 part by mass of fumed silica ("Aerogel #200" manufactured by Nippon Aerosil Co., Ltd.), and 0.2 parts 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 ("Perloil 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 for pipe lining materials (1).

(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.

(Comparative Example 1: Production of thermosetting resin composition (R1) for pipe lining material)
A thermosetting resin composition for pipe linings (R1) 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.

[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.
Good: Thixotropy is 2.0 or more; Bad: Thixotropy is less than 2.0

[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 gel formation was measured and the usable life was evaluated according to the following criteria.
◯: Time until gel formation is 90 hours or more ×: Time until gel formation is less than 90 hours

[Evaluation of rapid curing]
The 80°C gel time of the thermosetting resin composition for pipe lining material obtained above was measured in accordance with JIS K 6901, and the rapid curing property was evaluated according to the following criteria.
Good: gelation time is less than 3 minutes. Bad: gelation time is 3 minutes or more.

[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 a gap formed by sealing the entire area except for the upper edge of two glass plates whose inner surfaces had been treated with a release agent with a 3 mm thick silicone rubber packing. The composition was cured in a dryer at 50°C for 4 hours and then after-cured in a dryer at 120°C for 2 hours to prepare a cast plate, and various physical properties were measured.

[Bending 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 plates obtained above were subjected to a tensile test using 1B test pieces 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 the heat resistance was evaluated according to the following criteria.
○: 85°C or higher ×: Less than 85°C

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

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

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 properties, workability, and usable life were insufficient.

Claims (3)

A method for producing a cured product of a thermosetting resin composition for pipe lining material, which contains a resin component (A) essentially containing a maleic acid-modified epoxy (meth)acrylate (A1) and an unsaturated monomer (A2), a thermally decomposable curing agent (B), a curing accelerator (C) , and a thixotropic agent , wherein the amount of the thixotropic agent used is 0.1 to 5 parts by mass per 100 parts by mass of the resin component (A), and the maleic acid-modified epoxy (meth)acrylate (A1) is an epoxy (meth)acrylate. a reaction product of a hydroxyl group of the unsaturated monomer (A1) with maleic anhydride or an acid anhydride group or a carboxyl group of maleic acid, wherein the unsaturated monomer (A2) has an aromatic ring, and the thermally decomposable curing agent (B) is an alkyl perester and/or a percarbonate; and a method for producing a cured product of the thermosetting resin composition for a pipe lining material, the method comprising the step of heat-curing the thermosetting resin composition for a pipe lining material at 50 to 100°C. A method for producing a cured product of a thermosetting resin composition for pipe lining material according to claim 1, wherein the maleic acid-modified epoxy (meth)acrylate (A) is one in which 5 to 75 mol % of the hydroxyl groups of the epoxy (meth)acrylate (a1) have been esterified. A method for producing a cured product of the thermosetting resin composition for 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.