JP2023101941A - Intermediate base material, fiber reinforced composite, and molded body containing fiber reinforced composite - Google Patents

Abstract

To provide an intermediate substrate that can secure gas barrier properties by FRP alone, and demonstrates excellent mechanical properties as a fiber-reinforced composite.SOLUTION: An intermediate substrate comprises a curable liquid composition comprising meta-xylylene diisocyanate (A) and an alcohol component (B) comprising an unsaturated double bond, the curable liquid composition impregnated into a reinforcement material.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a fiber-reinforced composite material having excellent hydrogen gas barrier properties, an intermediate base material thereof, and a molded article containing the fiber-reinforced composite material.

In recent years, the development and use of fuel cells that generate electricity using hydrogen as a fuel are progressing from the standpoint of low environmental load. Conventionally, steel containers have been used as pressure containers for high-pressure gas, but for the purpose of weight reduction, pressure containers using resin materials, so-called FRP containers, are being developed for high-pressure hydrogen tanks.
The structure of a high-pressure hydrogen tank using a resin material includes a hollow container (liner) made of a thermoplastic resin having gas barrier properties in the inner layer, and a fiber reinforced plastic (FRP) with a thermosetting resin matrix as a reinforcing material in the outer layer. In particular, carbon fiber is used as a reinforcing material from the viewpoint of weight reduction (see Patent Documents 1 and 2, for example).
An epoxy resin is generally used as the thermosetting matrix resin. Epoxy resins are excellent in adhesiveness and toughness, have good adhesion to carbon fibers, and are advantageous in that a composite material with excellent mechanical properties can be obtained. On the other hand, epoxy resin has poor elongation and poor impact resistance.
In addition, general-purpose epoxy resin alone cannot be expected to have gas barrier properties, so in pressure vessels that require gas barrier properties, such as high-pressure hydrogen tanks, it is essential to use a liner with excellent gas barrier properties, such as a thermoplastic resin material.
In the case of using an intermediate base material in which continuous fiber bundles are pre-impregnated with a resin to form a prepreg, an epoxy resin matrix requires low-temperature storage. Furthermore, the epoxy resin takes a long time in the curing process, and there is a concern that the energy cost will increase as a whole.

JP-A-1-113227 JP-A-8-285189

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an intermediate base material that has excellent gas barrier properties even when FRP is used alone, and that has excellent mechanical properties when used as a fiber-reinforced composite material.

As a result of investigation, the inventors found that the above problem can be solved by impregnating the reinforcing material with a curable liquid composition containing meta-xylylene diisocyanate (A) and an alcohol component (B) containing an unsaturated double bond.

According to the present invention, a compact having excellent gas barrier properties can be produced from FRP alone.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below, but the present invention is not limited to the following descriptions as long as the gist thereof is not exceeded.
The intermediate base material of the present invention is obtained by impregnating a reinforcing material with a curable liquid composition containing meta-xylylene diisocyanate (A) and an alcohol component (B) containing an unsaturated double bond.

Alcohol component (B) includes an alcohol containing an unsaturated double bond. Here, the alcohol containing an unsaturated double bond means an alcohol having a radically polymerizable ethylenically unsaturated double bond. Alcohols containing unsaturated double bonds may be monoalcohols or polyhydric alcohols.
Monoalcohols containing unsaturated double bonds include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, trimethylolpropane di(meth)acrylate, glycidyl (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, diacrylated isocyanurate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, 2-acryloyloxyethylhexahydrophthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid and the like. These monoalcohols may be used alone or in combination of two or more.
Examples of polyhydric alcohols containing unsaturated double bonds include 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2,4-diethyl-1,5-pentanediol. Alkanediol di(meth)acrylates such as di(meth)acrylate, butylethylpropanediol di(meth)acrylate, 3-methyl-1,7-octanediol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated cyclohexanedimethanol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, propoxylated ethoxy) bisphenol A di(meth)acrylate, 1,1,1-trishydroxymethylethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxytri(meth)acrylate, trimethylolpropanepropoxytri(meth)acrylate, glycerolpropoxytri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and monopentaerythrin Examples include pentaerythritol acrylate compounds having a pentaerythritol structure and a (meth)acrylate structure, such as tall (meth)acrylate, dipentaerythritol (meth)acrylate, tripentaerythritol (meth)acrylate, and polypentaerythritol (meth)acrylate. These polyhydric alcohols may be used alone or in combination of two or more.

When the alcohol component containing unsaturated double bonds is a monoalcohol, the alcohol component (B) preferably further contains a polyhydric alcohol. The polyhydric alcohol in this case may be the above-described polyhydric alcohol containing an unsaturated double bond, or may be a polyhydric alcohol other than the above-described polyhydric alcohol containing an unsaturated double bond. Examples of such polyhydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,4-butenediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 2-ethyl-2-methylpropane-1,3-diol, 2- Butyl-2-ethylpropane-1,3-diol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,4-dimethyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol , triethylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, hydrogenated bisphenol A, tricyclodecanedimethanol, spiroglycol, polycondensation of unsaturated and/or saturated acids and polyhydric alcohols.
These polyhydric alcohols may be used alone or in combination of two or more.

Further, when the alcohol component containing an unsaturated double bond is a polyhydric alcohol, the alcohol component (B) may contain a polyhydric alcohol other than the aforementioned polyhydric alcohol containing an unsaturated double bond, or may contain a monoalcohol. The monoalcohol may be the above-described monoalcohol containing an unsaturated double bond, or may be a monoalcohol other than the above-described monoalcohol containing an unsaturated double bond.

The reinforcing material is not particularly limited and can be appropriately selected depending on the application. The reinforcement is preferably fibres. Examples of the fibers include glass fibers, carbon fibers, metal fibers, boron fibers, ceramic fibers, aramid fibers, zylon fibers, basalt fibers, cellulose fibers, polyoxymethylene fibers, aromatic polyamide fibers, polyparaphenylenebenzobisoxazole fibers, ultra-high molecular weight polyethylene fibers, and the like. In the present invention, carbon fiber is preferably used as the reinforcing material. By using carbon fibers, a lightweight and high-strength fiber-reinforced composite material can be obtained.

In producing the intermediate base material of the present invention, the method for impregnating the reinforcing material with the curable liquid composition is not particularly limited, and a known method can be appropriately selected according to the form of the reinforcing material.

The intermediate base material obtained by impregnating the reinforcing material with the curable liquid composition is partially polymerized by aging to obtain an intermediate base material containing a partially polymerized product of the curable liquid composition and the reinforcing material.
During aging, it is preferable to contain a urethanization reaction catalyst. Acidic catalysts and basic catalysts can be used as the urethanization catalyst, but neutral catalysts such as highly active tin compounds such as dibutyltin dilaurate and dibutyltin diacetate are preferred. The amount of the catalyst to be added varies depending on the other raw materials selected, but from the viewpoints of heat generation and urethane acrylate formation rate during aging, storage stability of the intermediate material, and mechanical properties of the cured product, it is preferably 800 ppm or less based on the weight of the curable liquid composition.
The aging conditions vary depending on the type and amount of catalyst used and other raw materials, but are generally 30 to 80° C. for 1 to 10 days, preferably 40 to 60° C. for 2 to 6 days.
The partially polymerized product of the curable liquid composition thus obtained contains urethane (meth)acrylate having a meta-xylylenediisocyanate residue.

Alternatively, a part of the curable liquid composition may be previously polymerized and then impregnated with the reinforcing material to obtain an intermediate base material containing a partially polymerized product of the curable liquid composition and the reinforcing material. When a part of the curable liquid composition is polymerized in advance and then impregnated into the reinforcing material, the curable liquid composition preferably further contains a polymerizable monomer. Examples of the polymerizable monomer include vinyl monomers, monofunctional (meth)acrylic acid esters, polyfunctional (meth)acrylic acid esters, and the like. If a polymerizable monomer that reacts with an isocyanate group is blended, the reaction during storage may increase the viscosity, resulting in poor workability and insufficient mechanical properties. Examples of the vinyl monomer include styrene, vinyltoluene, α-methylstyrene, and vinyl acetate. Further, monofunctional (meth)acrylates include methyl methacrylate, benzyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate and the like. Examples of polyfunctional (meth)acrylic acid esters include ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3-propanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tripropylene di(meth)acrylate, norbornene dimethanol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, ethylene oxide-added bisphenol A di(meth)acrylate, Propylene oxide-added bisphenol A di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tris(2-(meth)acryloyloxyethyl)isocyanurate and the like. These polymerizable monomers (E) can be used alone or in combination of two or more. From the viewpoint of tackiness and odor as an intermediate base material and the mechanical properties of the cured product, it is preferable to include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene di(meth)acrylate, benzyl methacrylate, dicyclopentenyl (meth)acrylate, ethylene oxide-added bisphenol A di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, propylene oxide-added bisphenol A di(meth)acrylate, and the like.
In the polymerization, it is preferable to contain a urethanization reaction catalyst. Acidic catalysts and basic catalysts can be used as the urethanization catalyst, but neutral catalysts such as highly active tin compounds such as dibutyltin dilaurate and dibutyltin diacetate are preferred. The amount of the catalyst to be added varies depending on the other raw materials selected, but from the viewpoints of heat generation and urethane acrylate formation rate during aging, storage stability of the intermediate material, and mechanical properties of the cured product, it is preferably 800 ppm or less based on the weight of the curable liquid composition.
The polymerization conditions vary depending on the type and amount of catalyst used and other raw materials, but are generally in the temperature range of 60 to 130°C, preferably in the temperature range of 80 to 110°C. The polymerization time may be in the range of 30 minutes to 12 hours, although reactivity varies greatly depending on the raw materials used.
The partially polymerized product of the curable liquid composition thus obtained contains urethane (meth)acrylate having a meta-xylylenediisocyanate residue.

The curable liquid composition preferably further contains a polymerization inhibitor. As the polymerization inhibitor, for example, known polyhydric phenol-based polymerization inhibitors such as hydroquinone, parabenzoquinone, methylhydroquinone, trimethylhydroquinone and toluhydroquinone can be used.
Although the amount of the polymerization inhibitor to be added varies depending on other raw materials to be selected, it is preferably 5000 ppm or less based on the weight of the curable liquid composition.

The curable liquid composition preferably further contains a radical polymerization initiator. Radical polymerization initiators include organic peroxides, for example, ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide; diacyl peroxides such as benzoyl peroxide; A carbonate system etc. are mentioned. These can be appropriately selected from the aging temperature, molding temperature, storage temperature, etc. of the intermediate substrate, and can be used alone or in combination of two or more. The amount of the radical polymerization initiator to be added may be 5 parts by mass or less, for example 0.05 to 5 parts by mass, per 100 parts by mass of the curable liquid composition.

Moreover, when providing photocurability to an intermediate base material, it is possible to use the radical polymerization initiator for photocuring. For example, acetophenones such as acetophenone, p-dimethylaminoacetophenone and p-dimethylaminopropiophenone, aminobenzophenones such as α-alkylaminobenzophenone, benzophenones such as benzophenone and 2-chlorobenzophenone, benzoin ethers such as benzoin methyl ether, benzyl ketals such as benzyl dimethyl ketal, anthraquinones such as 2-ethylanthraquinone and octamethylanthraquinone, organic peroxides such as cumene peroxide, and 2-merca. Thiol compounds such as ptobenzimidal, o-acyloxime compounds such as acetophenone o-benzoyloxime, and the like can be mentioned. These can be appropriately selected from the aging temperature, molding temperature, storage temperature, etc. of the intermediate substrate, and can be used alone or in combination of two or more. The amount of the radical polymerization initiator for photocuring to be added may be 5 parts by mass or less, for example 0.05 to 5 parts by mass, per 100 parts by mass of the curable liquid composition.

The intermediate base material obtained as described above can be cured by radical polymerization to form a fiber-reinforced composite material molded article that is a cured product.
The molding method includes a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, an internal pressure molding method, a sheet wrap molding method, and RTM, VaRTM, filament winding, RFI, etc. in which a reinforcing fiber filament or preform is impregnated with a curable resin composition and cured to obtain a molded product, but is not limited to these molding methods.
The molding temperature is preferably 70 to 180° C., more preferably 100 to 150° C., the molding time is preferably 2 to 60 minutes, and the molding pressure is preferably 0.1 to 10 MPa.
The fiber-reinforced composite material of the present invention can be used in applications that require hydrogen gas barrier performance, such as films, paints, composite materials, FRP containers, pressure vessels, automotive components, vehicle components, ship components, building components, medical components, or shelters. For example, due to the excellent gas barrier performance of FRP using the fiber-reinforced composite material of the present invention, a composite material with excellent gas barrier performance can be produced from the FRP outer layer alone without relying on the gas barrier performance of the liner.

EXAMPLES Next, the present invention will be specifically described with reference to examples. However, the present invention is in no way limited by these examples.

(Example 1)
In a container, 586.8 parts of meta-xylylene diisocyanate (manufactured by Mitsui Chemicals), 124.2 parts of ethylene glycol (manufactured by Mitsubishi Chemical), 288.1 parts of hydroxypropyl methacrylate (Light ester HOP (N) manufactured by Kyoei Co., Ltd.), 0.1 part of toluhydroquinone, 0.3 parts of toluhydroquinone, 0.3 parts of 4-methyl-2,6-ditertiary butylphenol, 0.6 parts of dibutyltin dilaurate, and Perbutyl E (monooxycarbonate-based organic peroxide manufactured by NOF Corporation) 9 .9 parts were added and mixed with stirring until uniform. The obtained curable liquid composition was designated as E-1.

(Example 2)
In a container, 587.9 parts of meta-xylylene diisocyanate (manufactured by Mitsui Chemicals), 123.1 parts of glycerin (manufactured by NOF Corporation), 288.1 parts of hydroxypropyl methacrylate (Light ester HOP (N) manufactured by Kyoei Co., Ltd.), 0.1 part of toluhydroquinone, 0.3 parts of 4-methyl-2,6-ditertiarybutylphenol, 0.06 parts of dibutyltin dilaurate, and Perbutyl E (monooxycarbonate-based organic peroxide manufactured by NOF Corporation) ) was added and mixed with stirring until uniform. The obtained curable liquid composition was designated as E-2.

(Comparative example 1)
In a container, 593.0 parts of isophorone diisocyanate (Vestanat IPDI manufactured by Evonik), 117.9 parts of 1,3-propanediol, 288.1 parts of hydroxypropyl methacrylate (Light ester HOP (N) manufactured by Kyoei Co., Ltd.), 0.1 part of toluhydroquinone, 0.3 parts of 4-methyl-2,6-ditertiary butylphenol, 0.6 parts of dibutyltin dilaurate, and perbutyl E (monooxycar manufactured by NOF Corporation) Bonate-based organic peroxide) (9.9 parts) was added and mixed with stirring until uniform. The resulting curable liquid composition was C-1.

(Comparative example 2)
871.3 parts of a bisphenol A type epoxy resin (NEOPOL 8250L manufactured by Nippon U-Pica Co., Ltd.), 8.7 parts of Perbutyl E (a monooxycarbonate organic peroxide manufactured by NOF Corporation), and 120 g of isophorone diisocyanate (Bestanat IPDI manufactured by Evonik) were added to a container and stirred until uniform. The obtained curable liquid composition was designated as C-2.

[Preparation of intermediate base material]
Carbon fibers (3K twill fabric TR3523M manufactured by Mitsubishi Chemical Corporation) were impregnated with the curable liquid compositions prepared in Examples 1 and 2 and Comparative Examples 1 and 2 so that the fiber weight was 60 wt %. It was aged at 50° C. for 48 hours to obtain an intermediate base material of CFRP (carbon fiber reinforced plastic). In Examples 1 and 2 using the curable liquid compositions E-1 and E-2, it was confirmed by tracking the absorption of the isocyanate group (around 2250 cm ⁻¹ ) in the infrared absorption spectrum that a urethane bond was formed between metaxylylene diisocyanate and hydroxypropyl methacrylate by aging at 50° C. for 48 hours.

[Preparation of composite material test piece]
The produced intermediate base material was press-molded for 10 minutes at 130° C. and 4 Bar using a 100-ton press (manufactured by Toho Press Mfg. Co., Ltd.) to obtain a composite material test piece.

<Measurement of hydrogen gas permeability coefficient>
Using the test piece obtained by the press molding, the hydrogen gas permeability coefficient was measured according to JIS K 7126-1. Table 1 shows the results obtained.
<Measurement of mechanical properties>
A bending test was performed according to JIS K 7171 using the test piece obtained by the press molding. Table 1 shows the results obtained.
An interlaminar shear test was performed according to JIS K 7078 using the test piece obtained by the press molding. Table 1 shows the results obtained.

表１より、本発明の中間基材を用いて製造された複合材料は力学物性に優れ、水素ガス透過係数が低く、ガスバリア性が良好であった。

From Table 1, the composite material produced using the intermediate base material of the present invention was excellent in mechanical properties, low in hydrogen gas permeability coefficient, and good in gas barrier properties.

The fiber-reinforced composite material, which is a cured product of the intermediate base material of the present invention, has excellent gas barrier properties such as hydrogen gas and excellent mechanical properties.

Claims (10)

meta-xylylene diisocyanate (A);
an alcohol component (B) containing an unsaturated double bond;
An intermediate substrate in which a reinforcing material is impregnated with a curable liquid composition comprising: meta-xylylene diisocyanate (A);
an alcohol component (B) containing an unsaturated double bond;
a partial polymer of a curable liquid composition containing
an intermediate substrate comprising a reinforcing material; meta-xylylene diisocyanate (A);
an alcohol component (B) containing an unsaturated double bond;
a partial polymer of a curable liquid composition containing
a polymerizable monomer (C);
An intermediate substrate having a reinforcing material impregnated with a partially polymerized composition comprising: The intermediate base material according to any one of claims 1 to 3, comprising a urethane (meth)acrylate having a meta-xylylene diisocyanate residue. The intermediate base material according to any one of claims 1 to 4, wherein the alcohol component (B) containing unsaturated double bonds contains a polyhydric alcohol. An intermediate substrate according to any one of claims 1 to 5, wherein the reinforcing material is fibre. 7. The intermediate substrate of claim 6, wherein said fibers are carbon fibers. A fiber-reinforced composite material which is a cured product of the intermediate base material according to any one of claims 1 to 7. A molded article comprising the fiber-reinforced composite material according to claim 8 . The molded article according to claim 9, which is a film, a paint, a composite material, an FRP container, a pressure vessel, an in-vehicle member, a vehicle member, a ship member, a building member, a medical member, or a shelter.