JP7217172B2 - Curing agent composition for thermosetting resin, thermosetting resin composition, inorganic-reinforced composite resin composition and molded article using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a curing agent composition for thermosetting resins, and thermosetting resin compositions, inorganic-reinforced composite resin compositions and molded articles using the same.

Fiber-reinforced resin molded products reinforced with reinforcing fibers are used in various structural applications, including casings and various members of automobiles and aircraft.

This fiber-reinforced resin molded article is usually manufactured using reinforcing fibers impregnated with a liquid resin or reinforcing fibers impregnated with a semi-cured resin. When manufacturing a fiber-reinforced resin molded product using reinforcing fibers impregnated with a liquid resin, molding methods such as hand lay-up molding, resin transfer molding, vacuum bag molding, and filament winding molding are used. Further, when manufacturing a fiber-reinforced resin molded product using a fiber-reinforced composite material, a molding method such as autoclave molding or press molding is used.

Here, the resin with which the reinforcing fibers are impregnated is generally required to be a resin that has both stability at room temperature and curability by heating or the like. Therefore, a thermosetting resin such as an epoxy resin is generally used as the resin.

When using a thermosetting resin, from the viewpoint of impregnating the reinforcing fibers and from the viewpoint of high-speed production, the thermosetting resin should have a low viscosity and a fast-curing property that cures quickly in the mold. required to have

Thermosetting resins are also required to exhibit excellent heat resistance and mechanical strength in the cured product so that the fiber-reinforced resin molded product can withstand the user's usage environment.

Here, in Patent Document 1, in addition to the epoxy resin, an amine curing agent having a primary amine or a secondary amine in the molecule is used as an epoxy resin composition used for producing a fiber-reinforced resin molded product. , an epoxy resin composition containing a phenolic hydroxyl group-containing amine compound having a phenolic hydroxyl group and a tertiary amine in the molecule and a phenol compound having a smaller active hydrogen equivalent than the phenolic hydroxyl group-containing amine compound has been proposed. . According to Patent Document 1, the epoxy resin composition having such a structure has low viscosity and fast curing properties, and can exhibit excellent heat resistance and mechanical strength in the resulting cured product. It is said that there is

JP 2016-98322 A

However, according to the studies of the present inventors, it has been found that when the epoxy resin composition disclosed in Patent Document 1 is used, a curing time of at least about 60 seconds is required. Thus, there is still room for improvement in rapid curability from the viewpoint of reducing processing costs during mass production of automobile parts and the like. Also, in order to improve the rapid curability, it is conceivable to improve the reactivity of the curing agent. However, simply increasing the reactivity of the curing agent increases the viscosity of the resin composition, making it impossible for the resin composition to flow sufficiently within the mold. As a result, there remains the problem that large parts cannot be manufactured.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a means capable of improving the fluidity before curing and the rapid curing property while maintaining the mechanical strength of the thermosetting resin composition.

The present inventors have made intensive studies to solve the above problems. In the course of this process, the inventors have found that the above problems can sometimes be solved by blending resorcinol with an amine curing agent and a prescribed phenolic hydroxyl group-containing amine compound to form a curing agent composition for thermosetting resins. Then, the inventors have found that the above problems can be solved by controlling the amount of resorcinol used relative to the thermosetting resin within a specific range, and have completed the present invention.

That is, according to one aspect of the present invention, an amine curing agent having a primary amine or a secondary amine in the molecule, and a phenolic hydroxyl group-containing amine compound having a phenolic hydroxyl group and a tertiary amine in the molecule. and resorcinol. The curing agent composition for thermosetting resin is also characterized in that it is blended with a thermosetting resin in an amount such that the mass ratio of resorcinol to 100 parts by mass of the thermosetting resin is 3 to 10 parts by mass. It has

ADVANTAGE OF THE INVENTION According to this invention, the fluidity|liquidity before hardening and rapid curability can be improved, maintaining the mechanical strength of a thermosetting resin composition.

One embodiment of the present invention comprises an amine curing agent having a primary amine or secondary amine in the molecule, a phenolic hydroxyl group-containing amine compound having a phenolic hydroxyl group and a tertiary amine in the molecule, and resorcinol. It is a curing agent composition for thermosetting resin, which is used by blending with a thermosetting resin in an amount such that the mass ratio of the resorcinol to 100 parts by mass of the thermosetting resin is 3 to 10 parts by mass.

[Curing agent composition for thermosetting resin]
As described above, the thermosetting resin curing agent composition according to the present embodiment includes an amine curing agent having a primary amine or a secondary amine in the molecule, and a phenolic hydroxyl group and a tertiary amine in the molecule. and resorcinol as essential components.

(Amine curing agent having a primary amine or secondary amine in the molecule)
As the amine curing agent having a primary amine or secondary amine in its molecule, there are no particular restrictions on its specific structure as long as it is a compound having a primary amine or secondary amine in its molecule. When such an amine curing agent is used, the mechanical strength of the resulting cured product can be improved as a result of introducing the amine curing agent onto the crosslinked network formed by the thermosetting resin such as epoxy resin.

Among such amine curing agents, amine curing agents having a primary amine in the molecule include, for example, aliphatic polyamine compounds and aromatic polyamine compounds having a primary amine in the molecule. Examples of aliphatic polyamine compounds include ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, diethylenetriamine, dipropylenetriamine, triethylenetetramine, triethylenetetramine, Propylenetetramine, tetraethylenepentamine, hexamethylenediamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6-trisaminomethylhexane, trimethylhexamethylenediamine, polyetherdiamine, diethylaminopropylamine, polyethyleneimine chain polyamine compounds such as dimer acid esters, dicyandiamide, tetramethylguanidine, adipic hydrazide, mensendiamine, 1,4-cyclohexanediamine, isophoronediamine, bis(aminomethyl)norbornane, bis(4-aminocyclohexyl ) methane, N-aminoethylpiperazine, diaminodicyclohexylmethane, bisaminomethylcyclohexane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5.5)undecane, norbornenediamine compounds such as alicyclic polyamine compounds such as Furthermore, epoxy-amine adducts obtained by reacting a mono- or polyepoxy compound with an amino group, Mannich-modified products obtained by reacting these compounds having an amino group with phenols and formaldehyde, polyamidoamines (the above a reaction product of polyamine and long-chain carboxylic acid, or a reaction product of the epoxy adduct and long-chain carboxylic acid). These can be used either singly or as a mixture of two or more.

Examples of aromatic polyamine compounds include 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, aromatic polyamine compounds such as diaminodiethyldiphenylmethane;

Examples of amine curing agents having a secondary amine in the molecule include aliphatic polyamine compounds and aromatic polyamine compounds having a secondary amine in the molecule. Examples of aliphatic polyamine compounds include linear polyamine compounds such as 1,2-propanediamine and 1,3-butanediamine; alicyclic polyamine compounds such as N-methylpiperazine, morpholine and piperidine; aromatic polyamine compounds such as aniline, N-ethylaniline, N-ethyltoluidine, diphenylamine, hydroxyphenylglycine, N-methylaminophenol sulfate;

Among the above-mentioned amine curing agents, from the viewpoint of improving the rapid curing function in the epoxy resin composition of the present invention, a linear polyamine compound or an oil having a primary amine or secondary amine in the molecule. Cyclic polyamine compounds are preferred.

(Phenolic hydroxyl group-containing amine compound having phenolic hydroxyl group and tertiary amine in the molecule)
The specific structure of the phenolic hydroxyl group-containing amine compound having a phenolic hydroxyl group and a tertiary amine in the molecule is not particularly limited as long as it is a compound having a phenolic hydroxyl group and a tertiary amine in the molecule. When such an amine compound is used together with resorcinol, which will be described later, the amine compound and resorcinol are introduced into the crosslinked network of the thermosetting resin described above, and a decrease in the glass transition temperature (a decrease in heat resistance) of the cured product is suppressed. be.

Examples of such phenolic hydroxyl group-containing amine compounds include compounds represented by the following structural formula (1).

In structural formula (1), each R ₁ independently represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group, and m is 1 to 4. and n is an integer of 1-5.

Here, the alkyl group having 1 to 4 carbon atoms includes methyl group, ethyl group, propyl group, isopropyl group, butyl group, t-butyl group and the like. The alkoxy group having 1 to 4 carbon atoms includes methoxy, ethoxy, propoxy, n-butoxy, t-butoxy and the like. Aralkyl groups include benzyl, phenylethyl, phenylpropyl, tolylmethyl, tolylethyl, tolylpropyl, xylylmethyl, xylylethyl, xylylpropyl, naphthylmethyl, naphthylethyl, and naphthylpropyl groups. mentioned.

Among these, R ₁ is preferably an alkyl group having 1 to 4 carbon atoms from the viewpoint of improving the fast-curing function in the thermosetting resin composition, and among these, R ₁ is preferably a methyl group. It is more preferable to have

Furthermore, as the phenolic hydroxyl group-containing amine compound, from the viewpoint of improving the fast-curing function in the thermosetting resin composition and expressing high heat resistance in the resulting cured product, in the above structural formula (1) , m is 1 or 2, n is an integer from 1 to 3, and most preferably both m and n are 1.

That is, the phenolic hydroxyl group-containing amine compound is particularly preferably a compound in which R ₁ is a methyl group, m is 1 or 2, and n is an integer of 1 to 3, and R ₁ is a methyl group and m and n are both 1 are most preferred.

Examples of phenolic hydroxyl group-containing amine compounds include compounds represented by the following structural formulas (1-1) to (1-6).

Examples of the phenolic hydroxyl group-containing amine compound include commercially available products such as Ancamine "K-54" (manufactured by Air Products Japan Co., Ltd.) and "DMP-30" (manufactured by Nisshin EM Co., Ltd.). is.

(resorcinol)
Resorcinol is a compound represented by the following structural formula (2) and is also called 1,3-dihydroxybenzene or resorcin.

One of the features of the thermosetting resin curing agent composition according to the present embodiment is that resorcinol is particularly selected as an ingredient. According to the studies of the present inventors, by blending the thermosetting resin so that the amount of resorcinol is the predetermined amount described later, excellent mechanical strength is exhibited and fluidity before curing is secured. However, it is possible to markedly improve the rapid curability.

The essential components of the thermosetting resin curing agent composition according to the present embodiment have been described above. Of course, it may further contain conventionally known various additives.

Although there is no particular limitation on the compounding amount of each component in the thermosetting resin curing agent composition according to the present embodiment, the compounding amount of the phenolic hydroxyl group-containing amine compound is preferably 5% with respect to 100% by mass of the amine curing agent. to 50% by mass, more preferably 10 to 28% by mass. The amount of resorcinol to be blended is preferably 15 to 40% by mass, more preferably 18 to 30% by mass, based on 100% by mass of the amine curing agent.

The curing agent composition for thermosetting resin according to the present embodiment is blended with a thermosetting resin as a main ingredient to form a thermosetting resin composition, and is used for curing the thermosetting resin by heat treatment. .

Here, the thermosetting resin to be cured is not particularly limited, and conventionally known thermosetting resins can be cured by the thermosetting resin curing agent composition according to the present embodiment. Examples of thermosetting resins include epoxy resins, phenolic resins, urea resins, melamine resins, and unsaturated polyester resins. Epoxy resin is particularly preferred.

Epoxy resins that are usually blended in conventional thermosetting resin compositions and epoxy resin compositions can be used without particular limitation. Examples of such epoxy resins include bisphenol type epoxy resins, biphenyl type epoxy resins, novolac type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, Alcohol type epoxy resins, phenol aralkyl type epoxy resins, epoxy resins having a naphthalene skeleton in the molecular structure, phosphorus atom-containing epoxy resins, and the like can be mentioned. These epoxy resins may be used alone, or two or more of them may be used in combination.

Bisphenol type epoxy resins include bisphenol A type epoxy resins and bisphenol F type epoxy resins. Biphenyl-type epoxy resins include biphenyl-type epoxy resins, tetramethylbiphenyl-type epoxy resins, and the like. Examples of alcohol-type epoxy resins include diglycidyl ether of 1,4-butanediol. Novolak type epoxy resins include phenol novolak type epoxy resins, cresol novolak type epoxy resins, bisphenol A novolak type epoxy resins, epoxidized products of condensates of phenols and aromatic aldehydes having phenolic hydroxyl groups, biphenyl novolak type epoxy resins, and the like. is mentioned. Epoxy resins having a naphthalene skeleton in the molecular structure include naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolak type epoxy resins, diglycidyloxynaphthalene, 1,1-bis(2,7-diglycidyloxy-1-naphthyl)alkane and the like.

Among the epoxy resins described above, novolak type epoxy resins and epoxy resins having a naphthalene skeleton are preferable from the viewpoint of heat resistance of the resulting cured product. Epoxy resins are preferred, and from the viewpoint of rapid curing and heat resistance of the resulting cured product, the epoxy equivalent is in the range of 165 to 200 g / eq, and the viscosity at 25 ° C. is in the range of 4,000 to 30,000 mPa s. A bisphenol A type epoxy resin is particularly preferred. In the present invention, the epoxy equivalent is a value measured in accordance with JIS K 7236 (2009), and the viscosity is measured using "TV-22" manufactured by Toki Sangyo Co., Ltd.

In addition, the thermosetting resin curing agent composition according to the present embodiment is also characterized by the compounding amount when it is mixed with a thermosetting resin to form a thermosetting resin composition and the thermosetting resin is cured. There is That is, in the thermosetting resin curing agent composition according to the present embodiment, the mass ratio of resorcinol contained in the composition is 3 to 10 parts by mass with respect to 100 parts by mass of the thermosetting resin, preferably It is used by blending with a thermosetting resin in an amount of 3 to 5 parts by mass. If the amount of resorcinol to be blended is less than 3 parts by mass with respect to 100 parts by mass of the thermosetting resin, sufficient rapid curability cannot be obtained, and there is a possibility that a cured product with a high curing rate cannot be obtained by heat treatment for a short period of time. . On the other hand, if the amount of resorcinol (melting point: 110°C) is more than 10 parts by mass based on 100 parts by mass of the thermosetting resin, the viscosity of the resulting thermosetting resin composition becomes too high, resulting in gelation in a short time. There is a possibility that sufficient fluidity may not be obtained due to storage.

[Thermosetting resin composition]
According to another aspect of the present invention, there is also provided a thermosetting resin composition containing a thermosetting resin and the above-described curing agent composition for thermosetting resin according to one aspect of the present invention. Here, since the specific configuration and preferred embodiments of the thermosetting resin contained in the thermosetting resin composition are as described above, detailed description thereof is omitted here.

Here, the thermosetting resin composition according to the present embodiment preferably has a gel time at 120° C. of 25 to 70 seconds. If the gel time at 120° C. is 25 seconds or more, the thermosetting resin composition according to the present embodiment has excellent impregnating properties into reinforcing fibers. On the other hand, if the gel time is 70 seconds or less, it is excellent in rapid curability. The gel time is the time until the composition loses fluidity and the viscosity rapidly increases, and is measured by the measurement method described in the Examples section below.

Furthermore, with regard to the thermosetting resin composition according to the present embodiment, the glass transition temperature of the obtained cured product is preferably in the range of 100 to 200°C. If the glass transition temperature is 100° C. or higher, the obtained cured product can express more excellent heat resistance. On the other hand, if the glass transition temperature is 200° C. or lower, the resulting cured product can exhibit better mechanical strength.

Furthermore, the thermosetting resin composition according to the present embodiment can exhibit even higher heat resistance in the resulting cured product. , the phenolic hydroxyl group-containing amine compound is preferably contained in a proportion of 0.5 to 10 parts by mass, and more preferably in a proportion of 0.5 to 5 parts by mass.

Furthermore, when an inorganic reinforcing material such as an inorganic fiber (reinforcing fiber) is impregnated with the thermosetting resin composition according to the present embodiment to produce an inorganic reinforced composite molding material, the thermosetting resin composition is 100 to 150 The minimum viscosity at °C is preferably 0.1 to 1000 mPa·s. The minimum viscosity at 100 to 150° C. means the minimum value of viscosity (viscosity at elevated temperature) within the temperature range from 100° C. to 150° C. when the thermosetting resin composition is heated. The temperature-rising viscosity can be measured, for example, using DSR-200 manufactured by Rheometric Co., Ltd. or a device having equivalent performance, at a frequency of 1 Hz, parallel plates (25 mmφ, gap 0.5 mm).

Here, if the minimum viscosity of the thermosetting resin composition at 100 to 150 ° C. is 0.1 mPa s or more, the inorganic reinforced composite molding material is put into a mold such as a mold to form a molded product of the inorganic reinforced composite material. During production, the thermosetting resin composition can be prevented from flowing excessively from the inorganic-reinforced composite molding material. In addition, if the minimum viscosity at 100 to 150° C. is 1000 mPa s or less, the thermosetting resin composition will flow sufficiently when producing a molded article of the inorganic reinforced composite molding material, and gas will not easily escape from the molded article. It is possible to prevent the molding from becoming unfilled and leaving unfilled portions in the molded product.

In addition, the above viscosity is measured with a frequency of 1 Hz and a parallel plate (25 mmφ, gap of 0.5 mm) using, for example, Rheometric's DSR-200 or an apparatus having equivalent performance, in the same manner as the temperature-programmed viscosity. can do. The minimum viscosity of the epoxy resin composition at 100° C. to 150° C. can be adjusted by the type and amount of each component constituting the thermosetting resin composition.

Furthermore, the thermosetting resin composition according to the present embodiment includes a curing accelerator, a curing agent other than an amine curing agent, a resin other than a thermosetting resin, a flame retardant, a filler, an additive, and an organic solvent. can be contained within a range that does not impair the The order of blending when producing the thermosetting resin composition is not particularly limited as long as the method can achieve the effects of the present invention. That is, all components may be mixed in advance and used, or may be mixed in order as appropriate. As for the blending method, for example, kneading can be carried out using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, or a Banbury mixer. Examples of various members that can be blended in the thermosetting resin composition according to the present embodiment are described below.
• Curing Accelerator Examples of the curing accelerator include tertiary amines containing no phenolic hydroxyl group. Examples of such curing accelerators include 3-phenyl-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 3-(3-chloro-4 -methylphenyl)-1,1-dimethylurea, urea derivatives such as 2,4-bis(3,3-dimethylureido)toluene, imidazole derivatives, phosphorus compounds, tertiary amines, organic acid metal salts, Lewis acids, amine complex salts and the like. When the curing accelerator as described above is used, the thermosetting resin composition according to the present embodiment is cured at a temperature lower than the normal curing temperature. When triphenylphosphine or 2-ethyl-4-methylimidazole is used as a curing accelerator, curability, heat resistance, electrical properties, humidity resistance reliability, etc. are excellent. The amount of curing accelerator used is preferably in the range of 0.01 to 1% by mass in the thermosetting resin composition.
- Curing Agents Other than Amine Curing Agents Examples of curing agents other than amine curing agents include acid anhydride compounds. Examples of acid anhydride compounds include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride and the like.
・Resins other than thermosetting resins Examples of resins other than thermosetting resins include polycarbonate resins, polyphenylene ether resins, polyamide resins, polyimide resins, polyamideimide resins, polyetherimide resins, polyethersulfone resins, and polysulfone resins. are mentioned.
• Flame retardant Although the flame retardant is not particularly limited, it is preferable to contain a non-halogen flame retardant that does not substantially contain a halogen atom in order to exhibit flame retardancy.

Examples of the non-halogen flame retardants include phosphorus flame retardants, nitrogen flame retardants, silicone flame retardants, inorganic flame retardants, organic metal salt flame retardants, and the like. A single flame retardant may be used, a plurality of flame retardants of the same system may be used, and flame retardants of different systems may be used in combination.
・Fillers Examples of fillers include titanium oxide, glass beads, glass flakes, calcium carbonate, barium carbonate, calcium sulfate, barium sulfate, potassium titanate, aluminum borate, magnesium borate, fused silica, crystalline silica, alumina, and nitride. Examples include silicon, aluminum hydroxide, and non-fibrous reinforcing agents. Moreover, these may be coated with an organic substance, an inorganic substance, or the like.
Additives Examples of additives include plasticizers, antioxidants, ultraviolet absorbers, stabilizers such as light stabilizers, antistatic agents, conductivity imparting agents, stress relaxation agents, release agents, crystallization accelerators, hydrolysis inhibitors, lubricants, impact agents, slidability improvers, compatibilizers, nucleating agents, reinforcing agents, reinforcing agents, flow control agents, dyes, sensitizers, coloring pigments, rubbery polymers, Thickeners, anti-settling agents, anti-sagging agents, anti-foaming agents, coupling agents, anti-rust agents, anti-bacterial/anti-mold agents, anti-fouling agents, conductive polymers and the like.
・Organic solvent Organic solvents include methyl ethyl ketone acetone, dimethylformamide, methyl isobutyl ketone, methoxypropanol, cyclohexanone, methyl cellosolve, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, acetone, methyl ethyl ketone, ketones such as cyclohexanone, ethyl acetate, Acetic esters such as butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate, carbitols such as cellosolve and butyl carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N - methylpyrrolidone and the like.

The thermosetting resin composition according to the present embodiment can exhibit excellent mechanical strength in the resulting cured product while having excellent fluidity and rapid curability. Therefore, it can be mixed with an inorganic reinforcing material to form an inorganic reinforced composite resin composition. Such an inorganic-reinforced composite resin composition becomes an inorganic-reinforced resin molded article by curing the resin component by heat treatment. That is, according to still another aspect of the present invention, there is also provided an inorganic reinforced composite resin composition containing the thermosetting resin composition according to one aspect of the present invention described above and an inorganic reinforcing material. Further, according to still another aspect of the present invention, an inorganic reinforced resin molded product (for example, a bonnet hood, a rear spoiler, a propeller shaft, Roof panel, boot lid, side sill, front pillar, center pillar, quarter pillar, roof rail, center floor, front floor, rear floor, upper back panel, rear par shell, wheel house, rear seat back, front side member, rear side member, battery case, inverter Auto parts such as cases, and parts integrated with some of these) are also provided.

The resulting inorganic reinforced resin molded article exhibits excellent mechanical strength, reflecting the excellent properties of the thermosetting resin composition described above. In addition, since the above-described thermosetting resin composition exhibits excellent fluidity, it is suitable for the production of large-sized molded products because it flows quickly in the mold when manufacturing inorganic-reinforced resin molded products. In addition, since the thermosetting resin composition described above exhibits excellent rapid curing properties, it is also suitable for mass production of inorganic reinforced resin molded articles. An inorganic reinforced resin molded article using the inorganic reinforced composite resin composition will be described below.

As described above, an inorganic reinforced resin molded product is a cured product of an inorganic reinforced composite resin composition, and more precisely, a molded product containing an inorganic reinforcing material and a cured product of a thermosetting resin composition. be.

Here, the inorganic reinforcing material most effectively improves physical properties such as strength, rigidity and heat resistance. Specifically, carbon fiber, glass fiber, carbon fiber, aramid fiber, alumina fiber, silicon carbide fibers, fibrous inorganic fibers such as zirconia fibers, whiskers such as aluminum borate and potassium titanate, acicular wollastonite, milled fibers, and the like. In addition to these, glass beads, glass flakes, glass balloons, silica, talc, kaolin, wollastonite, mica, alumina, hydrotalcite, montmorillonite, graphite, carbon nanotubes, fullerenes, zinc oxide, indium oxide, tin oxide, Iron oxide, titanium oxide, magnesium oxide, aluminum hydroxide, magnesium hydroxide, red phosphorus, calcium carbonate, potassium titanate, lead zirconate titanate, barium titanate, aluminum nitride, boron nitride, zinc borate, aluminum borate , barium sulfate, magnesium sulfate, and layered silicates subjected to an organic treatment for the purpose of delamination can also be used as inorganic reinforcing materials. Among these, inorganic fibers such as carbon fiber and glass fiber are particularly preferably used from the viewpoint of mechanical strength, and carbon fiber is particularly preferably used because of its light weight. These inorganic reinforcing materials may be used alone or in combination of two or more.

As a method for obtaining an inorganic reinforced composite resin molded article from the thermosetting resin composition according to one embodiment of the present invention, an intermediate material is produced by impregnating an inorganic reinforcing material with a varnished thermosetting resin composition, and heat is applied. A method of thermosetting a curable resin composition (for example, baking in a large autoclave) can be used. As an intermediate material, 1) a hand lay-up method or a spray-up method in which an inorganic reinforcing material is laid on a mold and a thermosetting resin composition is varnished in multiple layers, and 2) male and female molds are used. Using either one, a base material made of an inorganic reinforcing material is stacked while being impregnated with a varnished thermosetting resin composition, and a flexible mold capable of applying pressure is placed on the inorganic reinforcing material obtained above. 3) The SMC press method, in which a sheet of varnish containing an inorganic reinforcing material is formed into a sheet in advance and then compression-molded in a mold, 4) The inorganic reinforcing material is spread over the varnish. It can be produced by the RTM method or the like in which a varnished thermosetting resin composition is injected into a mating mold.

The temperature at which the inorganic reinforced resin molding is produced is usually adjusted within the temperature range of 80 to 220°C. More preferably, the temperature is in the range of 50 to 250°C, and it is particularly preferable to pre-cure at 50 to 100°C to obtain a tack-free cured product, and then to treat it at a temperature of 120 to 200°C. If the temperature is 50° C. or higher, sufficient rapid curability can be obtained. Moreover, if the temperature is 250° C. or lower, it is possible to suppress the occurrence of warping due to thermal strain in the obtained inorganic reinforced resin molded article.

The pressure for producing the inorganic reinforced resin molded product varies depending on the thickness and volume content of the inorganic reinforced composite resin composition, but is usually preferably adjusted within the pressure range of 98 to 980 kPa. When the above pressure is 98 kPa or more, the heat is sufficiently transmitted to the inside of the inorganic reinforced composite resin composition, and almost no uncured portions are eliminated. For this reason, it is possible to suppress the occurrence of warpage in the obtained inorganic reinforced resin molded article. On the other hand, if the above pressure is 980 kPa or less, it is possible to prevent the resin from flowing out into the mold before curing when producing an inorganic-reinforced resin molded article. For this reason, it is possible to suppress the occurrence of non-impregnated portions and the failure to obtain the desired volume fraction in the obtained inorganic reinforced resin molded article.

The volume content of the inorganic reinforcing material in the thus obtained inorganic reinforcing resin molded product is preferably in the range of 30 to 85%, more preferably in the range of 50 to 70%. If the volume content of the inorganic reinforcing material is within such a range, the molded article exhibits excellent mechanical strength, which is preferable.

In the above, inorganic reinforced resin moldings have been described in detail as applications of the thermosetting resin composition according to the present invention, but it can also be used for other applications such as fiber reinforced composite materials. Here, the fiber-reinforced composite material is a sheet-like intermediate material (prepreg) in which reinforcing fibers are impregnated with a semi-cured thermosetting resin composition. Moreover, it can also be used for the production of other cured products. For example, it may be used to produce a molded article having a predetermined shape (plate-like, rod-like, spherical, sheet-like, film-like, hollow, fine gas dispersion, foam, fibrous, pellet-like, etc.). Methods for obtaining such molded articles include injection molding, sheet molding, blow molding, injection blow molding, inflation molding, press molding, extrusion molding, foam molding, film molding, and secondary molding such as air pressure molding and vacuum molding. A process molding method may be used. Among these methods, it is preferable to appropriately select a preferable method according to each application. Also, the heating temperature conditions may be appropriately selected according to the type of curing agent to be combined, the application, and the like.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. In the following, "parts" and "%" are based on mass unless otherwise specified.

[Preparation of manufacturing raw materials]
The following materials were prepared as raw materials for producing a curing agent composition for thermosetting resins.

・Trimethylhexamethylenediamine (amine curing agent having primary or secondary amine in the molecule)
・α-(dimethylamino)cresol (phenolic hydroxyl group-containing amine compound having phenolic hydroxyl group and tertiary amine in the molecule)
• Resorcinol.

[Production of curing agent composition for thermosetting resin]
By mixing the production raw materials prepared above in the formulations shown in Table 1 below, curing agent compositions for thermosetting resins of Examples 1 to 3 and Comparative Examples 1 to 3 were produced.

[Production of thermosetting resin composition (epoxy resin composition)]
An epoxy resin (bisphenol A type epoxy resin; epoxy equivalent: 184 g/eq, viscosity (25°C): 10,100 mPa s) as a main agent is added to the thermosetting resin curing agent composition produced above and heated to 80°C. Thermosetting resin compositions (epoxy resin compositions) of Examples 1 to 3 and Comparative Examples 1 to 3 were produced by adding and mixing the mixture shown in Table 1 below. In addition, in the present examples and comparative examples, the value measured according to JIS K 7236 (2009) was adopted as the value of the epoxy equivalent of the bisphenol A type epoxy resin. As the viscosity value, the value measured by "TV-22" manufactured by Toki Sangyo Co., Ltd. was adopted.

[Evaluation of thermosetting resin composition]
(Evaluation of fluidity (measurement of gel time))
Immediately after the production of each thermosetting resin composition (epoxy resin composition) produced above, 1 cm ³ of the obtained epoxy resin composition was poured onto a hot plate at 120° C., and the epoxy resin was mixed while stirring with a stirring rod. The time until the composition lost its fluidity was measured. The results are shown in Table 1 below. In addition, regarding the results shown in Table 1, when the gel time was less than 25 seconds, it was indicated as "X", and when it was 25 seconds or more, it was indicated as "◯".

(Evaluation of rapid curability (measurement of degree of cure))
Each thermosetting resin composition (epoxy resin composition) produced above was subjected to DSC measurement (heating rate: 10° C./min) to measure the calorific value. On the other hand, the same composition was cured by heating at 120° C. for 35 seconds to obtain a cured product, and the obtained cured product was also subjected to DSC measurement under the same conditions to measure the calorific value. Then, the degree of cure was calculated according to the following formula from the calorific values before and after curing.

Curing degree [%] = {(calorific value before curing [J / g]) - (calorific value after curing [J / g])} / (calorific value before curing [J / g] x 100
The results are shown in Table 1 below. The results shown in Table 1 were evaluated as "x" when the degree of cure was less than 98%, and as "good" when the degree was 98% or more.

(Production of CFRP flat plate and evaluation of mechanical strength (measurement of tensile strength and tensile modulus))
Each of the thermosetting resin curing agent compositions produced above and an epoxy resin (bisphenol A type epoxy resin; epoxy equivalent 184 g / eq, viscosity (25 ° C.) 10,100 mPa s) as the main agent of the thermosetting resin ) and carbon fiber (manufactured by TK Industries, NCF (TKI300B127T), basis weight 300 g/m ² ), a CFRP flat plate was produced by HP-RTM (high pressure resin transfer molding). As production equipment, an 800-ton press machine manufactured by Kawasaki Yuko Co., Ltd. and a high-pressure cylinder injection machine manufactured by Polymer Engineering Co., Ltd. were used.

Specifically, the carbon fibers described above were cut into 6PLY (6 sheets) of 500×500×2 mmt, laminated, and placed on a mold. The lamination layout was 0, 90/+45, -45/0, 90/+45, -45/0, 90/+45, -45 from the top. Then, HP-RTM molding was performed under the conditions of a mold temperature of 120° C., a curing agent temperature in the tank of 30° C., a main agent (epoxy resin) temperature in the tank of 90° C., an injection speed of 30 cc/sec, and a mold clamping pressure of 450 tons. Also, the blending amount of the carbon fiber was adjusted to 50 parts by volume with respect to 100 parts by volume of the CFRP flat plate.

From the CFRP flat plate thus obtained, a tensile test piece was cut out by NC processing, and JIS K 7164 "Plastics-Testing methods for tensile properties-Part 4: Isotropic and orthotropic fiber reinforced plastic test conditions ” was measured for tensile strength. The test piece was a B-type according to JIS K 7165, had an outer size of 250×25 mm, and had a glass tag attached to each end of 50 mm on both sides of the test piece. Using a strength tester INSTRON 8501, a logger KEYENCE NR-500 series HA08 analog logger, a measuring instrument KEYENCE TM-3000 series TM065 and an optical dimension measuring instrument, the test was conducted at a test speed of 1 mm/min. Then, the average value of the five test pieces was used as the measured value of the tensile strength. The results are shown in Table 1 below.

Further, the tensile modulus was obtained from the average value of the slope of 1 to 3% displacement in the stress-strain curve obtained by measuring under the same conditions as the tensile strength measurement described above. Again, the average value of five test pieces was used as the measured tensile modulus. The results are shown in Table 1 below.

In Comparative Examples 1 and 2, the mechanical strength was not measured because the epoxy resin composition was not cured.

As can be seen from the results shown in Table 1, in Comparative Examples 1 and 2 in which the resorcinol content was less than 3 parts by mass with respect to 100 parts by mass of the epoxy resin, the heat treatment for 35 seconds did not provide sufficient curability. However, it was not possible to obtain a test piece from which the mechanical strength could be measured.

In Comparative Example 3, in which the amount of resorcinol (melting point: 110°C) was more than 10 parts by mass with respect to 100 parts by mass of the epoxy resin, the viscosity of the epoxy resin composition became too high, resulting in gelation in a short time. It can also be seen that sufficient liquidity was not obtained.

On the other hand, according to Examples 1 to 3, in which the amount of resorcinol compounded is 3 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin, the mechanical strength of the obtained test piece is maintained at a sufficient level, It was possible to achieve both excellent fluidity and rapid curability.

Claims (14)

Amine curing agent having a primary amine or secondary amine in the molecule (where the formula: H ₂ N(C _n H _2n )O(C _x H _2x )NH ₂ (where n and x are values of 2 to 7 ), except those with
a phenolic hydroxyl group-containing amine compound having a phenolic hydroxyl group and a tertiary amine in the molecule;
resorcinol and
including
A curing agent composition for thermosetting resin, which is blended with a thermosetting resin in an amount such that the mass ratio of the resorcinol to 100 parts by mass of the thermosetting resin is 3 to 10 parts by mass. 2. The curing agent composition for thermosetting resin according to claim 1, wherein the resorcinol is blended with the thermosetting resin in an amount such that the mass ratio of the resorcinol is 3 to 5 parts by mass. When the amine curing agent has a primary amine in the molecule, the amine curing agent is ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diamino Pentane, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetraethylenepentamine, hexamethylenediamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6-trisaminomethylhexane, trimethylhexa Methylenediamine, polyetherdiamine, diethylaminopropylamine, dimer acid ester of polyethyleneimine, dicyandiamide, tetramethylguanidine, adipic hydrazide, alicyclic polyamine compounds, aromatic polyamine compounds, mono- or polyepoxy compounds are reacted with amino groups. Epoxy-amine adducts obtained by, Mannich modified products obtained by reacting compounds having these amino groups with phenols and formaldehyde, and one or more selected from the group consisting of polyamidoamines. The curing agent composition for thermosetting resins according to claim 1 or 2. The curing agent composition for thermosetting resin according to any one of claims 1 to 3, wherein the content of resorcinol is 15 to 40% by mass with respect to 100% by mass of the amine curing agent. a thermosetting resin;
The curing agent composition for thermosetting resin according to any one of claims 1 to 4 ,
A thermosetting resin composition comprising: 6. The thermosetting resin composition according to claim 5 , wherein said thermosetting resin is an epoxy resin. 7. The thermosetting resin composition according to claim 5 , wherein the resorcinol content is 3 to 10 parts by mass with respect to 100 parts by mass of the thermosetting resin. 8. The thermosetting resin composition according to claim 7 , wherein the resorcinol content is 3 to 5 parts by mass with respect to 100 parts by mass of the thermosetting resin. The thermosetting resin composition according to any one of claims 5 to 8 ,
an inorganic reinforcing material;
An inorganic reinforced composite resin composition comprising: 10. The inorganic reinforced composite resin composition according to claim 9 , wherein the inorganic reinforcing material is inorganic fiber. The inorganic reinforced composite resin composition according to claim 10 , wherein the inorganic fibers are carbon fibers. The inorganic reinforcing composite resin composition according to any one of claims 9 to 11 , wherein the inorganic reinforcing material has a volume content of 30 to 85%. An inorganic reinforced resin molded article comprising a cured product of the inorganic reinforced composite resin composition according to any one of claims 9 to 12 . An automotive part comprising a cured product of the inorganic reinforced composite resin composition according to any one of claims 9 to 12 .