JP7610455B2 - Fiber Reinforced Plastic Composite Pipe - Google Patents

Description

The present invention relates to a resin composition and a fiber-reinforced plastic composite pipe.

Fiber-reinforced plastics (FRP) are used as composite materials in various fields such as agriculture, sewerage, construction, transportation, etc. Examples of molded products containing FRP (FRP molded products) include FRP composite pipes.
Unsaturated polyester resin is used as a resin in fiber reinforced plastics (FRP). When FRP is used outdoors, the resin in FRP is subject to photodegradation and hydrolysis due to ultraviolet rays, which causes thinning and cracks, making it difficult to maintain the strength of the FRP.

As a means for improving the weather resistance (resistance to discoloration due to sunlight) of FRP molded products, there is a method of forming a coating film by applying a weather-resistant paint to the outermost surface of the FRP molded product. When a coating film of weather-resistant paint is formed on the outermost surface of an FRP molded product, if the coating film is peeled off by a flying object, there is a problem that deterioration of the FRP progresses from the peeled off point.
To address these problems, there is a method of blending weather resistance additives such as ultraviolet absorbers and light stabilizers into the FRP resin (Patent Documents 1 to 3).

JP 2005-15610 A JP 2017-206630 A Japanese Patent Application Publication No. 62-64529

However, there was a problem that the weather resistance performance could not be maintained for a long period of time even if the weather resistance additive was simply blended with the resin. In addition, even if the amount of the weather resistance additive added was simply increased in order to maintain the weather resistance performance for a long period of time, the weather resistance performance could not be obtained commensurate with the amount added.
Therefore, an object of the present invention is to provide a resin composition having even more excellent weather resistance.

The present invention has the following aspects.
＜1＞
A resin composition comprising an iso-type unsaturated polyester resin (A) and an ultraviolet absorber (B) having a triazine skeleton.
＜2＞
The resin composition according to <1>, further comprising an ultraviolet absorber (C) having a benzotriazole skeleton.
＜3＞
The resin composition according to <1> or <2>, wherein the total amount of the ultraviolet absorber (B) and the ultraviolet absorber (C) is 0.1 to 5 mass% with respect to the total mass of the resin composition.
＜4＞
Further containing a hindered amine type light stabilizer (D),
<1> to <3>, wherein the content of the hindered amine type light stabilizer (D) relative to the total mass of the resin composition is 0.01 to 1 mass%.
＜5＞
Further containing a phenol-based antioxidant (E) and a phosphorus-based antioxidant (F),
The content of the phenol-based antioxidant (E) relative to the total mass of the resin composition is 0.01 to 1 mass%,
<4> The resin composition according to any one of <1> to <4>, wherein the content of the phosphorus-based antioxidant (F) relative to the total mass of the resin composition is 0.01 to 1 mass%.

＜6＞
It is cylindrical,
The structure includes, in order from the inner surface, an inner protective layer, an inner fiber reinforced resin layer, a resin mortar layer, an outer fiber reinforced resin layer, and an outer protective layer.
The fiber-reinforced plastic composite pipe has an outer fiber-reinforced resin layer comprising reinforcing fibers, an iso-unsaturated polyester resin (A), and an ultraviolet absorber having a triazine skeleton (B).
＜７＞
The fiber-reinforced plastic composite pipe according to <6>, wherein the outer surface protective layer comprises the iso-unsaturated polyester resin (A) and the ultraviolet absorber having a triazine skeleton (B).
＜8＞
The fiber-reinforced plastic composite pipe according to <7>, wherein the outer surface is coated with a weather-resistant paint.

The resin composition of the present invention further improves weather resistance.

FIG. 1 is a perspective view showing one embodiment of a fiber-reinforced plastic composite pipe of the present invention. 1 is a photograph of the surface of test piece 1 in Example 1. 1 is a surface photograph of test piece 2 of Comparative Example 1. 1 is a graph showing the measurement results of gloss retention in Example 3-1 and Comparative Example 3-1. 1 is a graph showing the measurement results of gloss retention in Example 3-2 and Comparative Example 3-2. 1 is a graph showing the measurement results of gloss retention in Examples 4-1 and 4-2, and Comparative Example 3-2.

In this specification, numerical ranges expressed using "to" include both ends of the numerical range.
In this specification, (meth)acrylic collectively refers to acrylic and methacrylic, and the same applies to (meth)acrylate, (meth)acryloyl, (meth)acryloyloxy, and (meth)acrylamide.

(Resin composition)
The resin composition of the present invention contains an iso-type unsaturated polyester resin (A), an ultraviolet absorber having a triazine skeleton (B), and an ultraviolet absorber having a benzotriazole skeleton (C).

<Iso-unsaturated polyester resin (A)>
By containing the isounsaturated polyester resin (A), the resin composition is cured to form a molded article.

The isounsaturated polyester resin (A) contains an unsaturated polyester (a1) and a polymerizable unsaturated monomer (a2).

It is preferable to use a saturated dibasic acid (a11), an unsaturated dibasic acid (a12), and a glycol (a13) as raw materials for the unsaturated polyester (a1).

The saturated dibasic acid (a11) is a dibasic acid that does not contain a non-conjugated double bond between carbon atoms in one molecule, such as orthophthalic acid, isophthalic acid, terephthalic acid, adipic acid, etc. The saturated dibasic acid (a11) may be used alone or in combination of two or more kinds, as necessary.
The unsaturated dibasic acid (a12) is a dibasic acid containing one or more carbon-carbon non-conjugated double bonds in one molecule, such as maleic anhydride or fumaric acid. The unsaturated dibasic acid (a12) may be used alone or in combination of two or more kinds, as necessary.

The glycol (a13) is a diol containing two hydroxy groups in one molecule, such as an alkylene glycol, such as ethylene glycol or propylene glycol, a polyoxyalkylene glycol, such as dialkylene glycol or trialkylene glycol, or a bisphenol, such as bisphenol A or bisphenol F. The glycol (a13) may be used alone or in combination of two or more types, as necessary.

The unsaturated polyester (a1) can further use, as a raw material, a monomer (a14) having one or two carbon atom-carbon non-conjugated double bonds in one molecule, which is not included in either the unsaturated dibasic acid (a12) or the glycol (a13). Examples of such monomers (a14) include, but are not limited to, styrene, propylene, dicyclopentadiene, and (meth)acrylic acid alkyl esters. The monomers (a14) may be used alone or in combination of two or more types, as necessary.

The synthesis method of the unsaturated polyester (a1) is not particularly limited, and may be a synthesis method in which a saturated dibasic acid (a11), an unsaturated dibasic acid (a12), a glycol acid (a13), and, if desired, a monomer (a14) are simultaneously charged and condensed.

Isounsaturated polyester resins (A) may be classified into ortho-unsaturated polyester resins, iso-unsaturated polyester resins, tere-unsaturated ester resins, or bis-unsaturated polyester resins depending on the type of saturated dibasic acid (a11) or the type of glycol (a13).

The polymerizable unsaturated monomer (a2) is not particularly limited, and any monomer that has been conventionally used in unsaturated polyester resins can be used.
Examples of the polymerizable unsaturated monomer (a2) include styrene, α-methylstyrene, chlorostyrene, dichlorostyrene, divinylbenzene, t-butylstyrene, vinyltoluene, vinyl acetate, diaryl phthalate, triaryl cyanurate, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, stearyl (meth)acrylate, tridecyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate ...methyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate ) acrylate, ethylene glycol monomethyl ether (meth)acrylate, ethylene glycol monoethyl ether (meth)acrylate, ethylene glycol monobutyl ether (meth)acrylate, ethylene glycol monohexyl ether (meth)acrylate, ethylene glycol mono 2-ethylhexyl ether (meth)acrylate, diethylene glycol monomethyl ether (meth)acrylate, diethylene glycol monoethyl ether (meth)acrylate, diethylene glycol monobutyl ether (meth)acrylate, diethylene glycol monohexyl ether (meth)acrylate, diethylene glycol mono 2-ethylhexyl ether (meth)acrylate, dipropylene glycol monomethyl ether (meth)acrylate, dipropylene glycol monoethyl ether (meth)acrylate, dipropylene glycol monobutyl ether (meth)acrylate, dipropylene glycol monohexyl ether (meth)acrylate, dipropylene glycol mono 2-ethylhexyl ether (meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polytetramethylene glycol dimethacrylate, 1 ,3-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 2-hydroxy-1,3-dimethacryloxypropane, 2,2-bis[4-(methacryloxyethoxy)phenyl]propane, 2,2-bis[4-(methacryloxydiethoxy)phenyl]propane, 2,2-bis[4-(methacryloxypolyethoxy)phenyl]propane, tetraethylene glycol diacrylate, bisphenol A ethylene oxide adduct (n=2) diacrylate, isocyanuric acid ethylene oxide adduct (n=3) diacrylate, and pentaerythritol diacrylate monostearate.
The polymerizable unsaturated monomer (a2) may be used alone or in combination of two or more kinds, as necessary.

The number average molecular weight of the isounsaturated polyester resin (A) is not particularly limited, but is preferably 400 to 1500, more preferably 400 to 1200, and even more preferably 400 to 1000. When the number average molecular weight of the (A) component is within the above range, the resin composition has good fluidity and better moldability.
The number average molecular weight is a value measured by GPC (gel permeation chromatography) analysis.

The content of the unsaturated polyester (a1) and the polymerizable unsaturated monomer (a2) in the isounsaturated polyester resin (A) is not particularly limited, but it is preferable that the unsaturated polyester (a1) is 80 to 60 parts by mass, and the polymerizable unsaturated monomer (a2) is the remainder, assuming that the total amount of the unsaturated polyester (a1) and the polymerizable unsaturated monomer (a2) is 100 parts by mass. In other words, the preferred range of the ratio represented by (a1)/{(a1)+(a2)} is 0.6 to 0.8. Within this range, the shrinkage, physical properties, and moldability of the isounsaturated polyester resin (A) will be better.

The isounsaturated polyester resin (A) may be mixed with compounds other than the compound used in the synthesis of the unsaturated polyester (a1) and the polymerizable unsaturated monomer (a2) to the extent that the effects of the present invention are not lost.

The resin content relative to the total mass of the resin composition is preferably 90.0 to 99.9% by mass, and more preferably 95.0 to 99.9% by mass. If the resin content is equal to or greater than the lower limit, the strength of the molded product (hereinafter sometimes referred to as the "resin molded product") that is the cured product of the resin composition can be further increased. If the resin content is equal to or less than the upper limit, the contents of the ultraviolet absorbers (B) and (C) can be increased to further improve weather resistance.

The content of component (A) in the resin composition is preferably 50 to 100% by mass, more preferably 75 to 100% by mass, and even more preferably 90 to 100% by mass, based on the total mass of the resins constituting the resin composition. If the content of the resin is equal to or greater than the lower limit, the strength of the resin molded body can be further increased. If the content of the resin is equal to or less than the upper limit, compatibility with the present formulation is improved, and weather resistance can be further increased.

Commercially available iso-unsaturated polyester resin (A) includes iso-unsaturated polyester resin (manufactured by Nippon U-Pica Co., Ltd.).

<Ultraviolet absorber (B)>
The ultraviolet absorber (B) is a compound having a triazine skeleton. By containing the ultraviolet absorber (B), the resin composition absorbs ultraviolet rays of 280 to 340 nm and improves the weather resistance of the resin molded body. It is preferable that the lower limit of the absorption wavelength range of the ultraviolet absorber (B) is lower than the lower limit of the absorption wavelength range of the ultraviolet absorber (C) described later.

Triazine is a compound represented by the following formula (b1):

The "compound having a triazine skeleton" refers to a compound represented by formula (b1) or a compound in which part or all of the hydrogen atoms of the compound represented by formula (b1) have been substituted with other substituents.
Examples of the substituent include a phenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a methoxyphenyl group, and a hydroxymethoxyphenyl group.

Examples of ultraviolet absorbers (B) include 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6 Examples include -(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-[2-hydroxy-4-(1-isooctyloxycarbonylethoxy)]-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine, and 2,4-diphenyl-6-(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine.

Examples of commercial ultraviolet absorbents (B) include LA-46 (manufactured by ADEKA Corporation) and EVERSORB40 (manufactured by Eiko Chemical Co., Ltd.).

The content of the ultraviolet absorber (B) in the resin composition is preferably 0.5 to 5 mass %, more preferably 0.5 to 2 mass %, based on the total mass of the resin composition. If the content of the ultraviolet absorber (B) is equal to or greater than the above lower limit, the weather resistance of the resulting resin molded body can be further improved. If the content of the ultraviolet absorber (B) is equal to or less than the above upper limit, the strength of the resulting resin molded body can be increased.

<Ultraviolet absorber (C)>
The ultraviolet absorber (C) is a compound having a benzotriazole skeleton. By containing the ultraviolet absorber (C), the resin composition absorbs ultraviolet rays of 290 to 400 nm and improves the weather resistance of the resin molded product.
The upper limit of the absorption wavelength range of the ultraviolet absorber (C) is preferably higher than the upper limit of the absorption wavelength range of the ultraviolet absorber (B).

Benzotriazole is a compound represented by the following formula (c1) or the following formula (c2).

The "compound having a benzotriazole skeleton" refers to a compound represented by formula (c1) or (c2), or a compound in which some or all of the hydrogen atoms of the compound of formula (c1) or formula (c2) have been substituted with other substituents.
Examples of the substituent include a hydroxyphenyl group, a 3-t-butyl-2-hydroxy-5-methylphenyl group, a 2-hydroxy-5-octylphenyl group, a 2-hydroxy-5-methylphenyl group, and a 2-hydroxy-3,5-di(1,1-dimethylbenzyl)phenyl group.

Examples of ultraviolet absorbers (C) include 2-(3'-t-butyl-2'hydroxy-5'-methylphenyl)5-chlorobenzotriazole, 3-(2H-benzotriazol-2-yl)-4-hydroxyphenethyl methacrylate (CAS: 153175-43-0), 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, and 2-(5-chloro-2H-benzotriazol-2-yl)-6-t-butyl-4-methylphenol.

Examples of commercial ultraviolet absorbers (C) include EVERSORB73 (manufactured by Nagamitsu Chemical Co., Ltd.), Vanalesin UVA-5080 (manufactured by Shin-Nakamura Chemical Co., Ltd.), JF-79 (manufactured by Johoku Chemical Co., Ltd.), JF-83 (manufactured by Johoku Chemical Co., Ltd.), and Adekastab LA-36 (manufactured by ADEKA Corporation).

The content of the ultraviolet absorber (C) in the resin composition is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 1.0% by mass, based on the total mass of the resin composition. If the content of the ultraviolet absorber (C) is equal to or greater than the above lower limit, the weather resistance of the resulting resin molded body can be further improved. If the content of the ultraviolet absorber (C) is equal to or less than the above upper limit, the strength of the resulting resin molded body can be increased.

The total amount of ultraviolet absorber (B) and ultraviolet absorber (C) in the resin composition (BC total amount) is preferably 0.6 to 5.0 mass%, more preferably 0.5 to 3.5 mass%, and even more preferably 1.0 to 3.0 mass%, based on the total mass of the resin composition. If the BC total amount is equal to or greater than the above lower limit, the weather resistance of the resulting resin molded product can be further improved. If the BC total amount is equal to or less than the above upper limit, the strength of the resulting resin molded product can be increased.

In the resin composition, the mass ratio (B/C ratio) of the ultraviolet absorber (B) to the ultraviolet absorber (C), represented by ultraviolet absorber (B)/ultraviolet absorber (C), is preferably 0.5 to 10.0, more preferably 1.0 to 5.0, and even more preferably 1.0 to 3.0. If the B/C ratio is within the above range, the weather resistance of the resin molded body can be further improved.

<Hindered amine type light stabilizer (D)>
The resin composition may contain a hindered amine type light stabilizer (D). The hindered amine type light stabilizer (D) is a compound having a hindered amine structure.
The compound having a hindered amine structure is a compound represented by the following formula (d1) or a compound in which some or all of the hydrogen atoms in the following formula (d1) have been substituted with other substituents.

Examples of the hindered amine type light stabilizer (D) include a compound having one hindered amine structure, a compound having two hindered amine structures, a compound having three hindered amine structures, a compound having four hindered amine structures, and a polymer having a hindered amine structure.
An example of the hindered amine type light stabilizer (D) is a compound having a 2,2,6,6-tetramethylpiperidine skeleton.
The types of the hindered amine type light stabilizer (D) include N-H type, N-R type, and N-OR type. In the present invention, the hindered amine type light stabilizer (D) may be any type, but from the viewpoints of compatibility and acid-basicity, the N-OR type is preferred.
The above hindered amine type light stabilizer (D) may be used alone or in combination of two or more kinds.

The content of the hindered amine light stabilizer (D) in the resin composition is preferably 0.01 to 1 mass %, more preferably 0.01 to 0.5 mass %, and even more preferably 0.1 to 0.3 mass %, relative to the total mass of the resin composition.

The hindered amine type light stabilizer (D) is not particularly limited, and any of those conventionally used in unsaturated polyester resins can be used.
Examples of the hindered amine type light stabilizer (D) include bis(2,2,6,6-tetramethyl-4-piperidyl)carbonate, bis(2,2,6,6-tetramethyl-4-piperidyl)oxalate, bis(2,2,6,6-tetramethyl-4-piperidyl)malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)adipate, bis(2,2,6,6-tetramethyl-4-piperidyl)terephthalate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)carbonate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)oxalate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)malonate, bis(1, Examples of such bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) adipate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) terephthalate, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide, 1,2-bis(2,2,6,6-tetramethyl-4-piperidyloxy) ethane, α,α'-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-p-xylene, bis(2,2,6,6-tetramethyl-4-piperidyl) tolylene-2,4-dicarbamate, and bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylene-1,6-dicarbamate can be mentioned.

In the resin composition, the mass ratio of the total amount of BC to the hindered amine type light stabilizer (D) ((B+C)/D ratio) is preferably 0.5 to 50, more preferably 5 to 20, and even more preferably 10 to 15. If the (B+C)/D ratio is equal to or greater than the above lower limit, the weather resistance can be further improved. If the (B+C)/D ratio is equal to or less than the above upper limit, poor curing of the resin composition can be effectively prevented, and the strength of the resin molded product can be further improved.

<Phenol-based antioxidant (E)>
The phenol-based antioxidant (E) is, for example, a compound represented by the following formula (e1): The phenol-based antioxidant (E) captures hydroperoxy radicals and functions as a primary antioxidant.

Examples of the phenol-based antioxidant (E) include 2,4-bis(octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)1,3,5-triazine, 4,6-bis(octylthiomethyl)-o-cresol, and 4,6-bis(dodecylthiomethyl).
Examples of commercial products of the phenol-based antioxidant (E) include AO-20 (manufactured by ADEKA Corporation), AO-60 (manufactured by ADEKA Corporation), and K-NOX1010 (manufactured by SUNKO INK Corporation).

The content of the phenolic antioxidant (E) in the resin composition is preferably 0.01 to 1 mass %, more preferably 0.05 to 0.5 mass %, and even more preferably 0.1 to 0.5 mass %, relative to the total mass of the resin composition. If the content of the phenolic antioxidant (E) is equal to or greater than the above lower limit, the weather resistance of the resin molded body can be further improved. If the content of the phenolic antioxidant (E) is equal to or less than the above upper limit, the strength of the resin molded body can be further increased.

<Phosphate-Based Antioxidant (F)>
The phosphoric acid-based antioxidant (F) is, for example, a compound represented by the following formula (f1): The phosphoric acid-based antioxidant (F) decomposes hydroperoxy radicals and functions as a secondary antioxidant.

P-(R ¹ ) ₃ ...(f1)
(In formula (f1), R ¹ is each independently a 2,4-di-tert-butylphenyl group or a nonylphenyl group.)

Examples of the phosphoric acid-based antioxidant (F) include 2,4,8,10-tetrakis(1,1-dimethylethyl)-6-[(2-ethylhexyl)oxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, tris(2,4-ditert-butylphenoxy)phosphine, and trisnonylphenylphosphite.
Examples of commercial products of the phosphoric acid-based antioxidant (F) include HP-10 (manufactured by ADEKA Corporation), 2112 (manufactured by ADEKA Corporation), and SB-PI719 (manufactured by SUNKO INK).

The content of the phosphoric acid-based antioxidant (F) in the resin composition is preferably 0.01 to 1 mass %, more preferably 0.05 to 0.5 mass %, and even more preferably 0.1 to 0.5 mass %, relative to the total mass of the resin composition. If the content of the phosphoric acid-based antioxidant (F) is equal to or greater than the above lower limit, the weather resistance of the resin molded body can be further improved. If the content of the phosphoric acid-based antioxidant (F) is equal to or less than the above upper limit, the strength of the resin molded body can be further increased.

The resin composition preferably contains both the phenol-based antioxidant (E) and the phosphoric acid-based antioxidant (F). By containing both the phenol-based antioxidant (E) and the phosphoric acid-based antioxidant (F), the weather resistance of the resin composition can be further improved.
In the resin composition, the total amount of the phenolic antioxidant (E) and the phosphoric acid antioxidant (F) (total EF amount) is preferably 0.02 to 2 mass%, more preferably 0.1 to 1.0 mass%, and even more preferably 0.1 to 0.5 mass%, based on the total mass of the resin composition. If the total EF amount is equal to or greater than the lower limit, the weather resistance of the resin molded article can be further improved. If the total EF amount is equal to or less than the upper limit, the strength of the resin molded article can be further increased.

In the resin composition, the mass ratio of the total amount of EF to the total amount of BC ((B+C)/(E+F) ratio) is preferably 10 to 30, and more preferably 10 to 15. If the (B+C)/(E+F) ratio is within the above range, the weather resistance can be further improved.

In the resin composition, the mass ratio (E/F ratio) of the phenolic antioxidant (E) to the phosphoric acid antioxidant (F), expressed as phenolic antioxidant (E)/phosphoric acid antioxidant (F), is preferably 0.5 to 2, more preferably 0.8 to 1.2. If the E/F ratio is within the above range, the weather resistance of the resin molded product can be further improved.

<Other ingredients>
The resin composition of the present invention may contain other components other than the above-mentioned components. Examples of other components include ultraviolet absorbers other than the ultraviolet absorber (B) and the ultraviolet absorber (C) (optional ultraviolet absorbers), light stabilizers other than the hindered amine type light stabilizers (optional light stabilizers), antioxidants other than the phenolic antioxidant (E) and the phosphoric acid antioxidant (F) (optional antioxidants), polymerization inhibitors, curing agents, curing accelerators, fillers, pigments, viscosity reducers, antiaging agents, plasticizers, flame retardants, stabilizers, or reinforcing materials.

As the optional ultraviolet absorbing agent, a benzophenone type ultraviolet absorbing agent can be exemplified.
The total amount of the ultraviolet absorber (B), the ultraviolet absorber (C) and the optional ultraviolet absorber (total amount of ultraviolet absorbers) is preferably 0.1 to 5 mass%, more preferably 0.5 to 1 mass%, based on the total mass of the resin composition.
The total amount of BC relative to the total amount of ultraviolet absorbers is preferably 60 to 100 mass %, more preferably 60 to 80 mass %. When the total amount of BC is equal to or more than the lower limit, the weather resistance of the resin molded product can be further improved.

Examples of the optional antioxidant include aromatic amine-based antioxidants (primary antioxidants), sulfur-based antioxidants (secondary antioxidants), and thioether-based antioxidants.
The total amount of the phenol-based antioxidant (E), the phosphorus-based antioxidant (F) and the optional antioxidant (total amount of antioxidants) is preferably 0.1 to 0.5 mass %, more preferably 0.1 to 0.2 mass %, based on the total mass of the resin composition.
The total amount of EF relative to the total amount of antioxidants is preferably 80 to 100 mass %, more preferably 90 to 100 mass %. When the total amount of EF is equal to or more than the lower limit, the weather resistance of the resin molded product can be further improved.

<Polymerization inhibitor>
The fiber reinforced plastic resin composition of the present invention may further contain a polymerization inhibitor.
By containing the polymerization inhibitor, the reaction between the unsaturated polyester (a1) and the polymerizable unsaturated monomer (a2) is suppressed, thereby improving safety.
The polymerization inhibitor is not particularly limited, but examples thereof include hydroquinone, toluhydroquinone, trimethylhydroquinone, tertiary butylhydroquinone, ditertiary butylhydroquinone, tertiary butylcatechol, methoxyhydroquinone, benzoquinone, tertiary butylquinone, and phenothiazine.
The polymerization inhibitor may be used alone or in combination of two or more kinds.
When the resin composition of the present invention contains a polymerization inhibitor, the content of the polymerization inhibitor is preferably 0.0001 to 0.1% by mass based on the total mass of the resin composition.

<Curing agent and curing accelerator>
In order to cure the resin composition of the present invention, it is preferable to add a curing agent and heat the composition. A curing accelerator may be used in combination with the curing agent.

<Hardening agent>
The curing agent is not particularly limited, but an organic peroxide catalyst is preferable. Examples of the organic peroxide catalyst include organic peroxides such as benzoyl peroxide, dicumyl peroxide, diisopropyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3,3-isopropyl hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, dicumyl hydroperoxide, acetyl peroxide, bis(4-t-butylcyclohexyl)peroxydicarbonate, diisopropyl peroxydicarbonate, isobutyl peroxide, 3,3,5-trimethylhexanoyl peroxide, and lauryl peroxide, as well as azo-based polymerization initiators such as azobisisobutyronitrile and azobiscarbonamide.
The curing agent may be used alone or in combination of two or more kinds.
When a curing agent is added to the resin composition, the amount of the curing agent added is not particularly limited, but is preferably 0.1 to 4 mass %, and more preferably 0.3 to 3 mass %, based on the total mass of the resin composition.
The curing agent is preferably added before the resin composition is molded. After the resin composition is molded, it is heated and cured to obtain a resin molded product having a specific shape.

<Curing accelerator>
The curing accelerator is not particularly limited, but examples thereof include metal soaps such as vanadyl octenate, copper naphthenate, barium naphthenate, cobalt naphthenate, and cobalt octenate, _Li3 [Co( _NO2 ) ₆ ], _{Li3 [} Co( _NO2 ) _5Cl ], Li3[Co _{( NO2} )5Br], _Li3 [Co( _NO2 ) _4Cl2 ], _{Li3 [} Co(NO2) _4Br2 ], _{Na3[ Co} ( _NO2 ) ₆ ], Na3 _[ Co( _NO2 )5Cl _] , _Na3 [ _Co ( _NO2 ) _5Br ], _Na3 [Co( _NO2 ) _{4Cl2 ]} , _Na3 [Co(NO ₂ ) ₄ Br ₂ ], K ₃ [Co(NO ₂ ) ₆ ], K ₃ [Co(NO ₂ ) ₅ Cl], K ₃ [Co(NO ₂ ) ₅ Br], K ₃ [Co(NO ₂ ) ₄ Cl ₂ ] and K ₃ [Co(NO ₂ ) ₄ Br ₂ metal chelate compounds such as vanadyl acetylacetate, cobalt acetylacetate, and iron acetylacetonate; and amines such as N,N-dimethylamino-p-benzaldehyde, N,N-dimethylaniline, N,N-diethylaniline, methylhydroxyethylaniline, N,N-dimethyl-p-toluidine, N,N-bis(2-hydroxyethyl)-p-toluidine, 4-N,N-dimethylaminobenzaldehyde, 4-N,N-bis(2-hydroxyethyl)aminobenzaldehyde, 4-methylhydroxyethylaminobenzaldehyde, N,N-bis(2-hydroxypropyl)-p-toluidine, N-ethyl-m-toluidine, triethanolamine, m-toluidine, diethylenetriamine, pyridine, phenylmorpholine, piperidine, and diethanolaniline.
The curing accelerator may be used alone or in combination of two or more kinds.
When the resin composition contains a curing accelerator, the content of the curing accelerator is preferably 0.001 to 5 mass % based on the total mass of the resin composition.
The curing accelerator may be added to the resin composition before the curing agent is added, or may be added to the resin composition simultaneously with the curing agent.

The total of the above components is 100% by mass.

<Method of producing resin composition>
The method for producing the resin composition of the present invention is not particularly limited, but may be, for example, the following method.
First, an ultraviolet absorber, and if necessary, a light stabilizer and an antioxidant are added to an unsaturated polyester resin, and then the mixture is kneaded to obtain a kneaded product. When mixing various additives with the unsaturated polyester resin, one or more selected from a filler, an additive, and a curing accelerator may be mixed together, if desired. Next, a curing agent is mixed into the kneaded product, and the mixture is further kneaded.
Various modifications are possible, such as adding the curing accelerator and the curing agent immediately before producing a resin molded body (cured product).

(Resin Molded Body)
The resin molded article is obtained by curing the resin composition of the present invention and forming it into any desired shape.
Examples of resin molded articles include resin parts of FRP, fiber-reinforced plastic composite pipes, manholes, drainage manholes, building material blocks, pavement blocks, covers, pipe materials, repair materials, and other molded articles for civil engineering and construction, artificial marble molded articles, landscape molded articles, chairs, benches, CC (for underground burial of information and communication power) boxes, information-related molded articles, and power-related molded articles.

<Method of manufacturing resin molded body>
The method for producing the resin molded body is not particularly limited, but examples thereof include cast molding, centrifugal molding, compression molding, and continuous molding.

In the cast molding method, a resin composition is poured into a mold and heated to harden.
In centrifugal molding, a resin composition is poured into a cylindrical mold, the mold is then rotated, and the centrifugal force causes the resin composition to be shaped to a uniform thickness, and the resin composition is then heated and cured.
In the compression molding method, a resin composition is poured into a mold, compressed by a press, and heated to harden.
In the cast molding method, centrifugal molding method, and compression molding method, reinforcing fibers may be placed in a mold, impregnated with a resin composition, and cured to form FRP. Examples of reinforcing fibers include glass fibers, carbon fibers, and boron fibers. The thickness (diameter) of the reinforcing fibers is, for example, 5 to 30 μm. The reinforcing fibers may be in the form of a bundle or sheet aligned in one direction, or may be a plain weave or twill weave fabric.

In the continuous molding method, the resin composition is wound around a rotating mandrel, and the resin composition is passed through a curing oven while being fed forward at a constant speed, where it is heated and cured. Before or after winding the resin composition, reinforcing fibers may be wound around it, and the resin composition impregnated into the wound fibers may be cured to produce FRP.

The curing temperature of the resin composition is not particularly limited, but is preferably 50°C or higher, more preferably 50 to 60°C, and even more preferably 55 to 65°C.
The curing time of the resin composition is not particularly limited, but is preferably 6 hours or more, more preferably 12 hours or more, and further preferably 24 to 48 hours.

(Fiber reinforced plastic composite pipe)
An embodiment of a fiber reinforced plastic composite pipe (FRPM pipe) of the present invention will be described with reference to FIG.
The FRPM pipe 1 in FIG. 1 is cylindrical and extends in the direction of the pipe axis O, and has an annular or tubular resin mortar layer 4, an inner surface fiber reinforced resin layer 3 located on the inner surface of the resin mortar layer 4, an outer surface fiber reinforced resin layer 5 located on the outer surface of the resin mortar layer 4, an inner surface protective layer 2 located on the inner surface of the inner surface fiber reinforced resin layer 3, and an outer surface protective layer 6 located on the outer surface of the outer surface of the outer fiber reinforced resin layer 5.
That is, the FRPM pipe 1 has, in order from the inner periphery side, an inner protective layer 2, an inner fiber reinforced resin layer 3, a resin mortar layer 4, an outer fiber reinforced resin layer 5, and an outer protective layer 6. It is sufficient to have only one of the inner fiber reinforced resin layer 3 and the outer fiber reinforced resin layer 5, but it is preferable to have both. It is not necessary to have either the inner protective layer 2 or the outer protective layer 6, but it is preferable to have one or both.
The FRPM pipe is not limited to a cylindrical shape, but may be a rectangular pipe shape or other angular pipe shape.

In this embodiment, the inner surface fiber reinforced resin layer 3 has a first inner surface fiber reinforced resin layer 3a in which the fibers extend in the circumferential direction, and a second inner surface fiber reinforced resin layer 3b in which the fibers extend in the axial direction. However, the present invention is not limited to this, and the inner surface fiber reinforced resin layer 3 may be composed of a single layer. In this case, the reinforcing fibers that make up the inner surface fiber reinforced resin layer 3 may be woven.

In this embodiment, the outer fiber-reinforced resin layer 5 has a first outer fiber-reinforced resin layer 5a in which the fibers extend in the circumferential direction, and a second outer fiber-reinforced resin layer 5b in which the fibers extend in the axial direction. However, the present invention is not limited to this, and the outer fiber-reinforced resin layer 5 may be composed of a single layer. In this case, the reinforcing fibers that make up the outer fiber-reinforced resin layer 5 may be woven.

The resin composition forming the inner protective layer 2 may be a conventionally known resin composition containing a thermosetting resin (such as a composition having an iso-based unsaturated polyester resin and a curing agent) or the resin composition of the present invention.

An example of the inner surface fiber-reinforced resin layer 3 is a combination of reinforcing fibers and a cured resin composition. This resin composition is the same as the resin composition that forms the inner surface protective layer 2.

The resin mortar layer 4 is a hardened product of a resin concrete composition. The resin concrete composition may be, for example, a mixture of resin mortar and aggregate.
Examples of resin mortar include thermosetting resins such as unsaturated polyester resins.
Examples of the aggregate include those that have been conventionally mixed in resin concrete compositions, such as silica sand, gravel, crushed stone, boulders, blast furnace slag aggregate, artificial lightweight aggregate, etc. The average particle size of the aggregate is, for example, 0.1 to 10 mm.
In the resin concrete, the amount of aggregate per 100 parts by mass of resin mortar is, for example, 60 to 90 parts by mass.
The resin concrete composition may contain additives such as a polymerization inhibitor, a hardener, and a hardening accelerator.

An example of the outer fiber-reinforced resin layer 5 is a combination of reinforcing fibers and a resin composition. This resin composition is the same as the resin composition that forms the inner protective layer 2. Among these, the resin composition of the present invention is preferred as the resin composition that forms the outer fiber-reinforced resin layer 5. By using the resin composition of the present invention, the weather resistance of the outer fiber-reinforced resin layer 5 can be improved, and the weather resistance of the FRPM pipe can be improved.

The resin composition forming the outer protective layer 6 is the same as the resin composition forming the inner protective layer 2. In particular, the resin composition forming the outer protective layer 6 is preferably the resin composition of the present invention. By forming the outer protective layer 6 from the resin composition of the present invention, the weather resistance of the resin molded body is improved, and the weather resistance of the FRPM pipe can be improved.

The inner diameter R of the FRPM pipe 1 can be determined appropriately depending on the application of the FRPM pipe 1.
The length of the FRPM pipe 1 in the pipe axis O1 direction can be determined appropriately depending on the application of the FRPM pipe 1.
The thickness of each layer constituting the FRPM pipe 1 can be appropriately determined in relation to the inside diameter R, the length in the direction of the pipe axis O1, the strength required of the FRPM pipe 1, and the like.

<Manufacturing method of FRPM pipe>
The method for manufacturing the FRPM pipe 1 is not particularly limited, and examples of the method include conventionally known manufacturing methods such as a filament winding method, a centrifugal molding method, a pultrusion method, or a hand lay-up method.
The filament winding method is a manufacturing method in which a core tube is rotated and fed at a constant speed, and the materials for the inner protective layer 2, inner fiber reinforced resin layer 3, resin mortar layer 4, outer fiber reinforced resin layer 5, and outer protective layer 6 are sequentially wound around the core tube and successively heated and hardened to continuously manufacture FRPM pipes. With these methods, FRPM pipes of various sizes can be manufactured by changing the size of the core tube.

Examples of a method for manufacturing the FRPM pipe 1 include the method for manufacturing an FRPM pipe described in Japanese Patent Application Laid-Open No. 2001-205711, paragraphs [0016] to [0019], the method for manufacturing an FRPM pipe described in Japanese Patent Application Laid-Open No. 2001-205712, paragraphs [0020] to [0028], and the method for manufacturing an FRPM pipe described in Japanese Patent Application Laid-Open No. 10-193467, paragraphs [0009] to [0019].
That is, an endless steel belt is wound spirally around the circumferential surface of a cylindrical mold rotating around the tube axis, and a resin composition for forming the inner protective layer 2, a reinforcing fiber, a resin composition for FRP, a resin concrete composition, a reinforcing fiber, a resin composition for FRP, and a resin composition for forming the outer protective layer 6 are supplied in this order to the surface of the wound steel belt, and each resin composition is cured to continuously form an FRPM pipe 1. The steel belt advances with the rotation of the cylindrical mold, and returns from the end of the cylindrical mold to the start of the mold through the inside of the mold. Therefore, the FRPM pipe 1 is stretched in the axial direction of the cylindrical mold. The stretched FRPM pipe 1 is cut to an arbitrary length to obtain a product of the FRPM pipe 1.
According to this manufacturing method, the inner diameter R of the FRPM pipe 1 can be adjusted by changing the outer diameter of the mold.

The FRPM pipe of the present invention is not limited to the above-mentioned embodiment. The FRPM pipe of the present invention may have an outer surface coated with a weather-resistant paint in order to further improve weather resistance. That is, the FRPM pipe of the present invention may have a coating layer of a weather-resistant paint on the outermost surface.
Generally, in order to prevent deterioration of the constituent base material of outdoor structures, piping, transport equipment, etc., a coating is applied to the outermost layer. By covering with a coating film by painting, the influence of deterioration factors such as ultraviolet rays, moisture, temperature, and adhesion of foreign matter on the constituent members can be suppressed. Examples of weather-resistant paints include fluorine-based paints, silicon-based paints, and acrylic paints. Examples of weather-resistant paints include top coats that are applied to the surface of FRP products for outdoor use. From the viewpoint of further increasing adhesion with FRPM pipes, fluorine-based paints and acrylic paints are more suitable as weather-resistant paints.
Examples of the coating method include spray coating, brush coating or roller coating, etc. Among these, spray coating is preferred in terms of the stability of the film thickness and the finished appearance.
By providing a weather-resistant paint coating layer on the outer surface, the transmission of ultraviolet light and moisture to the resin composition that constitutes the FRPM pipe is further reduced, thereby further improving weather resistance.
The coating amount of the weather-resistant coating material is, for example, preferably 80 to 300 g/ ^cm2 , and more preferably 200 to 260 g/ ^cm2 .

According to the resin composition of the present invention, the resin composition contains an ultraviolet absorber (B) and an ultraviolet absorber (C). Since the resin composition of the present invention contains two types of ultraviolet absorbers with different structures, it can absorb ultraviolet rays of different wavelengths. Therefore, the weather resistance can be improved compared to conventional resin compositions.
The resin composition of the present invention is particularly suitable as a resin composition for FRP.

The present invention will be explained in more detail below using examples, but the technical scope of the present invention is not limited to the examples described below, and various modifications are possible as long as they do not change the gist of the present invention.

(Raw materials used)
<Ultraviolet absorbing agent>
Two parts by mass of a triazine-based ultraviolet absorber (A) (LA-46: manufactured by ADEKA Corporation) and one part by mass of a benzotriazole-based ultraviolet absorber (B) (EVERSORB73: manufactured by Eiko Chemical Industry Co., Ltd.) were mixed to prepare a mixed ultraviolet absorber of 3 parts by mass in total.

<Light stabilizers>
0.2 parts by mass of a hindered amine type light stabilizer (D) having an N-OR type functional group (EVERSORB95: manufactured by Eiko Chemical Co., Ltd.) was prepared.

<Antioxidants>
0.1 parts by mass of a phenol-based antioxidant (E) (primary antioxidant, K-NOX 1520: manufactured by Shuko Ink Co., Ltd.) and 0.1 parts by mass of a phosphoric acid-based antioxidant (F) (secondary antioxidant, 2112: manufactured by ADEKA Corporation) were mixed to prepare 0.2 parts by mass of a mixed antioxidant.

(Example 1-1)
3 g of the mixed ultraviolet absorber, 0.2 g of the hindered amine type light stabilizer (D), and 0.3 g of the mixed antioxidant were mixed together. The mixture obtained was kneaded with 100 g of an unsaturated polyester resin (iso-unsaturated polyester resin), and 0.3 g of an accelerator (cobalt naphthenate) in a mixer to obtain a kneaded product.

To the obtained kneaded product, 1.2 g of a curing agent (Permec N, manufactured by NOF Corporation) was added and cured to obtain a resin composition 1.
Resin composition 1 was impregnated into 5 layers of UCF UD tape (width 120 mm × length 25 mm) (manufactured by Hokuriku Glass Fiber Co., Ltd.) by hand layup (manual work). The UD tape impregnated with resin composition 1 was heated at 60°C for 180 minutes to prepare an FRP. This FRP was designated as "test piece 1".
An accelerated weather resistance test was carried out on the test piece 1, and the color difference of the test piece 1 was measured every 250 hours from the start of irradiation. The results are shown in Table 1.

(Test Method)
<Accelerated weather resistance test>
An accelerated test was carried out using a test device (Sunshine Metal Weather, manufactured by Suga Test Instruments Co., Ltd.).
<Color difference measurement>
The color difference was measured using a test device (NTQ-S-M-902-93, integrating sphere spectrophotometer Ci17800, manufactured by Sakata Inx Engineering Co., Ltd.).
For the test pieces subjected to the accelerated weather resistance test, the color difference (unit: ΔE), L ^* (unit: none) representing the degree of black and white, a ^* (unit: none) representing the degree of red-green, and b ^* (unit: none) representing the degree of yellow-blue were measured every 250 hours from the start of irradiation.

(Comparative Example 1-1)
An FRP was produced in the same manner as in Example 1, except that neither the ultraviolet absorber (B) nor the ultraviolet absorber (C) was blended. This FRP was designated "test piece 2."
Accelerated weather resistance testing was performed on test piece 2, and the temperature difference of test piece 2 was measured every 250 hours from the start of irradiation. The results are shown in Table 2.

(Comparative Example 1-2)
A resin composition was prepared in the same manner as in Example 1, except that the ultraviolet absorber (B) was not blended and the ultraviolet absorber (C) was blended. This resin composition was cured by heating at 60° C. for 180 minutes to obtain "test piece 3".
The accelerated weather resistance test was carried out on the test piece 3, and the color difference of the test piece 3 was measured every 250 hours from the start of irradiation. The results are shown in Table 3.

Comparing the color difference change of Example 1-1 (Table 1) and the color difference change of Comparative Example 1-1 (Table 2) after 2000 hours of accelerated testing, the color difference change ΔE of Example 1 was 37% smaller than the color difference change ΔE of Comparative Example 1-1 (Table 3). Similarly, the color difference change ΔE of Example 1-1 was 22% smaller than the color difference change ΔE of Comparative Example 1-2.
In addition, a digital microscope (VHX-6000, manufactured by Keyence Corporation) was used to observe the surfaces of Test Piece 1 and Test Piece 2 after 2000 hours of the accelerated test. Comparing the surface state of Example 1 (FIG. 2) with the surface state of Comparative Example 1-1 (FIG. 3) after 2000 hours of the accelerated test, no cracks were generated on the surface of Example 1-1, but numerous cracks were generated on the surface of Comparative Example 1-1.
From these results, it was confirmed that application of the present invention makes it possible to absorb ultraviolet rays over a wide wavelength range and improve weather resistance.

(Examples 2-1 to 2-4)
According to the "Paint Type" and "Sample Preparation Conditions" in Table 5, a coating film was formed on the surface of the FRPM pipe prepared in Example 1-1.
The FRPM pipes of each example thus obtained were subjected to an accelerated weather resistance test (accelerated test color difference ΔE) and an evaluation of adhesion. The results are shown in Table 5.
The types of paint are as follows:
- Fluorine-based resin: Duflon Fresh 100 (manufactured by Nippon Paint Co., Ltd.).
- Acrylic urethane 1: Enamel series (manufactured by Mikuni Paint).
Top coat: NR82 series (manufactured by TOMATEC).
- Acrylic urethane 2: Ultima (manufactured by Kubo Takashi Paint Co., Ltd.).

<Adhesion>
The adhesion was confirmed by the cross-cut method in accordance with JIS K5600-5-6 (1999). The adhesion was evaluated according to the classification in Table 4, and a classification of 0 to 2 (effect of 15% or less) was judged to be "excellent adhesion."

As shown in Table 5, Examples 2-1 and 2-2, which were coated with a fluororesin (fluorine-based paint) or an acrylic urethane (acrylic paint), had smaller accelerated test color difference ΔE and higher adhesion than Example 2-3, which was coated with a top coat. Among them, Example 2-2 had a smaller ΔE after 500 hours than Examples 2-1 and 2-3.
In addition, in Example 2-4, after the paint was cured to form a coating film, the coating film peeled off, so no evaluation was performed.

(Example 3-1)
The gloss retention of the FRPM pipe of Example 1-1 was measured, and the results are shown in FIG.

<Gloss retention>
Using a gloss meter (Gloss Checker, manufactured by Simple Co., Ltd.), the gloss retention was measured every 250 hours during the accelerated weather resistance test described above.

(Comparative Example 3-1)
The gloss retention of the FRPM pipe of Comparative Example 1-1 was measured, and the results are shown in FIG.

(Example 3-2)
The gloss retention of the FRPM pipe of Example 2-2 (having a coating of acrylic urethane 1) was measured, and the results are shown in FIG.

(Comparative Example 3-2)
In the same manner as in Example 2-2, a coating film was provided on the FRPM pipe of Comparative Example 1-1 (a coating film of acrylic urethane 1 was formed). The gloss retention of the obtained FRPM pipe was measured, and the results are shown in FIG.

4, in Example 3-1, the decrease in gloss retention was gradual (deterioration was slow), and no cracks were observed on the surface until the accelerated test time reached 1500 hours. In Comparative Example 3-1, the surface condition changed due to hydrolysis and photodegradation immediately after the start of the accelerated test, and the decrease in gloss retention was greater than in Example 3-1.
5, in both Example 3-2 and Comparative Example 3-2, the decrease in gloss retention was gradual (deterioration was slow). When the acceleration time exceeded 2000 hours, Example 3-2 had a significantly higher gloss retention than Comparative Example 3-2.
From the results in Figures 4 and 5, it was confirmed that weather resistance could be further improved by coating the outer surface with weather-resistant paint.

(Example 4-1)
2 g of a triazine-based ultraviolet absorber (A) (LA-46: manufactured by ADEKA Corporation) and 1 g of a hindered amine-type light stabilizer (D) (EVERSORB95: manufactured by Eiko Chemical Industry Co., Ltd.) having an N-OR functional group were mixed together. The resulting mixture was kneaded with 100 g of an unsaturated polyester resin (iso-type unsaturated polyester resin) and 0.3 g of an accelerator (cobalt naphthenate) in a mixer to obtain a kneaded product.

1.2 g of a curing agent (Permec N, manufactured by NOF Corporation) was added to the resulting kneaded product and cured to obtain a resin composition.
The resin composition was impregnated into 5 layers of UCF UD tape (120 mm wide x 25 mm long, manufactured by Hokuriku Glass Fiber Co., Ltd.) by hand layup. The UD tape impregnated with the resin composition was heated at 60°C for 180 minutes to produce an FRP. The gloss retention of this FRP was measured in the same manner as in Example 3-1, and the results are shown in Table 6 and FIG.

(Example 4-2)
An FRP was produced in the same manner as in Example 4-1, except that the amount of triazine-based ultraviolet absorber (A) (LA-46: manufactured by ADEKA Corporation) was 0.2 g, and the amount of hindered amine-type light stabilizer (D) (EVERSORB95: manufactured by Eiko Chemical Industry Co., Ltd.) having an N-OR functional group was 0.1 g. The gloss retention of this FRP was measured, and the results are shown in Table 6 and FIG.

(Comparative Example 4-1)
An FRP was produced in the same manner as in Example 4-1, except that the triazine skeleton ultraviolet absorber (A) and the N-OR functional group hindered amine type light stabilizer (D) were not blended in. The gloss retention of this FRP was measured, and the results are shown in Table 6 and FIG.

As shown in Table 6 and Figure 6, from 500 to 2500 hours, the decrease in gloss retention rate was significantly slower in Examples 4-1 and 4-2 than in Comparative Example 4-1.

REFERENCE SIGNS LIST 1 Fiber-reinforced plastic composite pipe 2 Inner surface protective layer 3 Inner surface fiber-reinforced resin layer 3a First inner surface fiber-reinforced resin layer 3b Second inner surface fiber-reinforced resin layer 4 Resin mortar layer 5 Outer surface fiber-reinforced resin layer 5a First outer surface fiber-reinforced resin layer 5b Second outer surface fiber-reinforced resin layer 6 Outer surface protective layer

Claims (1)

It is cylindrical,
The structure includes, in order from the inner surface, an inner protective layer, an inner fiber reinforced resin layer, a resin mortar layer, an outer fiber reinforced resin layer, and an outer protective layer.
The outer surface fiber reinforced resin layer has reinforcement fibers, an iso-based unsaturated polyester resin (A), and an ultraviolet absorber having a triazine skeleton (B),
the outer surface protective layer comprises the iso-unsaturated polyester resin (A) and the ultraviolet absorber having a triazine skeleton (B),
A fiber-reinforced plastic composite pipe whose outer surface is coated with weather-resistant paint .

Images