WO2017033632A1

WO2017033632A1 - Epoxy resin composition and fiber-reinforced composite material

Info

Publication number: WO2017033632A1
Application number: PCT/JP2016/071383
Authority: WO
Inventors: 小林　厚子; 森永　邦裕; 松井　茂樹
Original assignee: Dic株式会社
Priority date: 2015-08-27
Filing date: 2016-07-21
Publication date: 2017-03-02

Abstract

Provided are: an epoxy resin composition which has low viscosity and sufficient pot life and enables a cured product thereof to exhibit high heat resistance and fracture toughness; a cured product having the above-described properties; a fiber-reinforced composite material; a fiber-reinforced resin molded article; and a method for producing a fiber-reinforced resin molded article. An epoxy resin composition which is characterized by containing (a) an epoxy resin having an average number of functional groups of 1.5-2.2, (b) an acid anhydride, (c) a polyol compound containing two or more alcoholic hydroxyl groups in each molecule, while having a hydroxyl equivalent of from 30 g/eq to 650 g/eq, and (d) a curing accelerator.

Description

Epoxy resin composition and fiber reinforced composite material

The present invention relates to an epoxy resin composition that can exhibit high heat resistance and fracture toughness in a cured product obtained while having a low viscosity and sufficient pot life, a cured product having the above performance, and a fiber-reinforced composite material The present invention relates to a fiber-reinforced resin molded product and a method for producing a fiber-reinforced resin molded product.

Fiber reinforced resin molded products reinforced with reinforcing fibers are attracting attention for their light weight and excellent mechanical strength, and their use in various structural applications such as automobile and aircraft casings and various components has expanded. ing.

A fiber reinforced resin molded product can be manufactured by applying a molding method such as a filament winding method, a press molding method, a hand layup method, a pultrusion method, and an RTM method to a fiber reinforced composite material.

Fiber reinforced composite materials consist of a structure in which reinforced fibers are impregnated with resin, and as resins used in fiber reinforced composite materials, usually stability at normal temperature and durability and strength of cured products are required. In general, thermosetting resins are frequently used.

When a thermosetting resin is used as the resin for the fiber reinforced composite material, it is essential that the resin for the fiber reinforced composite material can be impregnated into the reinforcing fiber as described above. It is required to have a long so-called pot life, which is a viscosity and has a small increase in viscosity during impregnation.

Furthermore, when the fiber reinforced resin molded product is used for structural parts such as engines and wire core materials, the thermosetting resin can be obtained so that the fiber reinforced resin molded product can withstand a severe use environment for a long time. The cured product is required to exhibit high heat resistance and mechanical strength.

Examples of materials that can be used in such applications include (A) bisphenol type epoxy resins, (B) acid anhydride curing agents, (C) imidazole compounds, (D) polyols having aromatic rings, and all epoxies. There is provided an epoxy resin composition containing 10 to 20 parts by mass of (C) and 10 to 20 parts by mass of (D) with respect to 100 parts by mass of the total amount of resin (see, for example, Patent Document 1). However, the epoxy resin composition provided in Patent Document 1 has a problem that pot life is not sufficient, and it is difficult to impregnate reinforcing fibers when producing a large molded product.

[A] a polyfunctional epoxy resin that is liquid at room temperature or has a softening point of 65 ° C. or lower, and is at least selected from a phenol novolac epoxy resin, a cresol novolac epoxy resin, and a triphenylmethane epoxy resin One polyfunctional epoxy resin, [B] alicyclic epoxy resin, [C] acid anhydride curing agent, [D] curing accelerator, and [A] / [B] mass blending ratio [A] / An epoxy resin composition for molding a fiber-reinforced composite material RTM in which [B] is in the range of 55/45 to 95/5 is also provided (see, for example, Patent Document 2). However, the cured product obtained from this epoxy resin composition has a problem that the mechanical strength is insufficient.

That is, it was difficult to obtain an epoxy resin composition that can be used for applications that should have both high heat resistance and mechanical strength in the obtained cured product while having a low viscosity and sufficient pot life.

JP 2010-163573 A International Publication No. 2012/102202

Therefore, the problem to be solved by the present invention is an epoxy resin composition that has a low potency and has a sufficient pot life and can exhibit high heat resistance and fracture toughness in the resulting cured product, It is providing the manufacturing method of the hardened | cured material which has performance, a fiber reinforced composite material, a fiber reinforced resin molded product, and a fiber reinforced resin molded product.

As a result of intensive studies to solve the above problems, the present inventors have used an epoxy resin composition having a predetermined epoxy resin, an acid anhydride, a predetermined polyol compound, and a curing accelerator. The present inventors have found that the above problems can be solved, and have completed the present invention.

That is, the present invention comprises an epoxy resin (a) having an average functional group number of 1.5 to 2.2, an acid anhydride (b), two or more alcoholic hydroxyl groups in the molecule, and a hydroxyl group equivalent. An epoxy resin composition comprising a polyol compound (c) of 30 g / eq to 650 g / eq and a curing accelerator (d), a cured product thereof, and a fiber-reinforced composite essentially comprising reinforcing fibers The present invention provides a material, a fiber-reinforced resin molded article, and a method for producing the same.

According to the present invention, an epoxy resin composition that has a low potency and has a sufficient pot life, and can exhibit high heat resistance and fracture toughness in the resulting cured product, a cured product having the above performance, A fiber-reinforced composite material, a fiber-reinforced resin molded product, and a method for producing a fiber-reinforced resin molded product can be provided.

The epoxy resin composition of the present invention has an epoxy resin (a) having an average functional group number of 1.5 to 2.2, an acid anhydride (b), two or more alcoholic hydroxyl groups in the molecule, and An epoxy resin composition having a polyol compound (c) having a hydroxyl group equivalent of 30 g / eq to 650 g / eq, and a curing accelerator (d).

・ Epoxy resin (a)
The epoxy resin (a) used in the present invention is not particularly limited as long as it is an epoxy resin having an average functional group number of 1.5 to 2.2, but from the viewpoint of further improving the heat resistance of the resulting cured product, An epoxy resin having a functional group number of 1.8 to 2.2 is more preferable.

Examples of the epoxy resin (a) include a bisphenol type epoxy resin and a biphenyl type epoxy resin, but it is preferable to use a bisphenol type epoxy resin from the viewpoint that the cured product is more excellent in toughness. These epoxy resins may be used independently and may mix 2 or more types.

Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol AD type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, halides of these bisphenol type epoxy resins, and alkyl-substituted products. Therefore, it is preferable to use a bisphenol A type epoxy resin or a bisphenol F type epoxy resin because a cured product having more excellent fracture toughness is easily obtained.

Examples of the biphenyl type epoxy resin include tetramethyl biphenyl type epoxy.

・ Acid anhydride (b)
The acid anhydride (b) used in the present invention may be any compound that has an acid anhydride group in the molecule and can cure the epoxy resin (so-called curing agent for epoxy resin), and is particularly limited. is not. Examples of the acid anhydride (b) include unsaturated carboxylic acid anhydrides such as cyclic aliphatic acid anhydrides, aromatic acid anhydrides, and maleic anhydride. Examples of the cyclic aliphatic acid anhydride include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylendoethylenetetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, And methyl nadic acid. Examples of the aromatic acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Examples of the unsaturated carboxylic acid anhydride include maleic anhydride. Among these, it is preferable to use a cyclic aliphatic acid anhydride from the viewpoint of obtaining a cured product having excellent mechanical properties. Further, among the cyclic aliphatic acid anhydrides, a compound having a viscosity at 25 ° C. of 500 mPa · s or less is more preferable because the epoxy resin composition is excellent in impregnation into reinforcing fibers.

Polyol compound (c)
The polyol compound (c) used in the present invention is not particularly limited as long as it has two or more alcoholic hydroxyl groups in the molecule and has a hydroxyl group equivalent of 30 g / eq to 650 g / eq. Examples of such a polyol compound (c) include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6 as divalent alcohol compounds. -Hexanediol, 2-butyl-2-ethyl-1,3-propanediol, compounds having an aromatic ring or cyclo ring and two alcoholic hydroxyl groups in the molecule, and the like. , Trimethylolpropane, glycerin and the like, and examples of the tetravalent alcohol compound include pentaerythritol.

In addition, from the viewpoint of having a sufficient pot life while having a low viscosity and further improving fracture toughness and heat resistance in the obtained cured product, a divalent alcohol compound is used as the polyol compound (c). Among them, it is preferable to use a compound having an aromatic ring or a cyclo ring and two alcoholic hydroxyl groups in the molecule. Further, among these, the polyol compound (c) is a compound having an aromatic ring or a cyclo ring, a polyalkylene oxide chain, and two alcoholic hydroxyl groups in the molecule because the fracture toughness of the cured product is further excellent. It is preferable to use it. Such a compound can be represented, for example, by the general formula (1).

However, A in the formula (1) represents a divalent linking group containing an aromatic ring or a cyclo ring, B represents a divalent linking group containing a polyalkylene oxide, and OH represents an alcoholic hydroxyl group.

A in the general formula (1) is not particularly limited as long as it is a divalent linking group containing an aromatic ring or a cyclo ring as described above, but the following structural formulas (A-1) to (A-7) It is preferable that it is a bivalent coupling group represented by the structure shown by the point that compatibility is good when using a bisphenol type epoxy resin as said epoxy resin (a).

However, in structural formulas (A-1) to (A-7), * B represents a bonding point with B in the general formula (1).

Further, as A in the general formula (1), among the divalent linking groups represented by the structural formulas (A-1) to (A-7), the resulting epoxy resin composition has a lower content. In terms of structural formulas (A-4) to (A-7), it has a sufficient pot life while exhibiting viscosity, and can exhibit higher fracture toughness and heat resistance in the obtained cured product. The divalent linking group shown is more preferable, and among them, the divalent linking group represented by (A-4) is particularly preferable.

B in the general formula (1) is not particularly limited as long as it is a divalent linking group containing a polyalkylene oxide as described above. From the viewpoint of obtaining a cured product having higher mechanical strength, The average value of the sum of the number of repeating units of the two polyalkylene oxide chains is preferably in the range of 2 to 18, more preferably 2 to 6. The polyalkylene oxide chain has an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide as a repeating unit, and may have the same structure or may be different for each repeating unit. Alternatively, it may take a block polymerization form.

The number of carbon atoms in the alkylene moiety in the repeating unit of the polyalkylene oxide chain is not particularly limited, but preferably 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably. Ethylene oxide or propylene oxide having 2 to 4 carbon atoms and particularly preferably 2 to 3 carbon atoms is preferred.

That is, in the general formula (1), a divalent linking group containing a polyalkylene oxide chain represented by (B-1) or (B-2) is particularly preferable.

In the above formulas (B-1) and (B-2), x and y are the number of repeating units of two polyalkylene chains in one molecule, each independently representing an integer of 1 or more, and an average value thereof Is preferably in the range of 1-9. In the formulas B-1) and (B-2), * A and * OH represent bonding points with A and OH, respectively, in the general formula (1).

Therefore, the polyol compound is particularly preferably a compound having a structure represented by the following structural formulas (1-1) to (1-2).

In structural formulas (1-1) to (1-2), x1, x2, y1, and y2 are each independently an integer of 1 or more, and the average values of x1, x2, y1, and y2 are 1 to 9, respectively. is there.

Examples of the polyol compound (c) having the structure as described above include 2,2-bis (4-polyoxyethylene-oxyphenyl) propane and 2,2-bis (4-polyoxypropylene-oxyphenyl) propane. In particular, 2,2-bis (4-polyoxypropylene-oxyphenyl) propane is particularly preferable from the viewpoint of the resulting composition having a lower viscosity and good heat resistance of the cured product.

The hydroxyl group equivalent of the polyol compound (c) used in the present invention is 30 g / eq to 650 g / eq from the viewpoint of balancing the pot life of the composition with the fracture toughness of the resulting cured product. In particular, the range of 30 g / eq to 450 g / eq is preferable from the viewpoint that the performance is further expressed.

The polyol compound (c) has a boiling point at normal pressure of 100 ° C. or higher, preferably 140 ° C. or higher, more preferably 180 ° C. or higher. When the boiling point of the polyol compound (c) is too low, the polyol compound is produced in the process of injecting the epoxy resin composition into the mold or the process of curing the epoxy resin composition when producing a fiber reinforced resin molded product. Since (c) is easy to vaporize, voids may occur in the resulting cured product and fiber reinforced resin molded product, and it may be necessary to devise measures such as lowering the curing temperature or slowing the curing reaction. is there. In addition, when using the said multiple types of said polyol compound (c), it is preferable that all satisfy | fill the said conditions.

・ Curing accelerator (d)
The curing accelerator (d) may be any compound that can improve the curing activity such as the acid anhydride contained in the epoxy resin composition, and is generally a curing accelerator of an epoxy resin and an acid anhydride. What is used as can also be used in the present invention. Examples of such a curing accelerator (d) include urea derivatives, imidazole derivatives, phosphorus compounds, tertiary amines, organic acid metal salts, Lewis acids, amine complex salts, and the like.

In particular, examples of the curing accelerator (d) generally used in an epoxy / acid anhydride curing system include imidazole derivatives. Specifically, imidazole, 2-methylimidazole, 2-ethyl 4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, 1 -Cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole and the like can be mentioned. In addition, when high storage stability is required, a latent catalyst that is a mixture of an imidazole compound and a compound having a hydroxyl group such as phosphorous acid, phosphorous acid monoester, and phosphorous acid diester should also be used. I can do it.

Epoxy resin composition The epoxy resin composition of the present invention has the above-described epoxy resin (a), acid anhydride (b), two or more alcoholic hydroxyl groups in the molecule, and a hydroxyl group equivalent of 30 g / The polyol compound (c) of eq to 650 g / eq and the curing accelerator (d) may be essential, and the others are not particularly limited, but a sufficient pot life can be obtained, and the reinforcing fiber From the viewpoint of having a good balance between the good impregnation of the resin, the curing reaction proceeds promptly, the productivity is improved, and the mechanical strength of the resulting cured product is further improved. The curing accelerator (d) is 0 when the total mass of the epoxy resin (a), the acid anhydride (b), the polyol compound (c) and the curing accelerator (d) is 100 parts by mass. .1 part by mass to 5 parts It is preferably contained at a ratio of 0.0 part by mass.

Furthermore, in the epoxy resin composition of the present invention, from the viewpoint of obtaining a sufficient pot life and more excellent heat resistance of the obtained cured product, the diol compound (c) is composed of the epoxy resin (a), the above-mentioned When the total mass of the acid anhydride (b) and the curing accelerator (d) is 100 parts by mass, it is preferably contained in a proportion of 1 to 20 parts by mass.

Furthermore, in the epoxy resin composition of the present invention, the blending ratio of the epoxy resin (a), the acid anhydride (b), and the diol compound (c) is the sum of the epoxy resin (a) and the diol compound. The ratio of the functional group equivalent to the functional anhydride equivalent of the acid anhydride is preferably 1.0 / 0.7 to 1.0 / 1.0.

-Other resin The epoxy resin composition of the present invention may contain compounds other than the essential components described above. Examples of such compounds include acid-modified polybutadiene, polyether sulfone resin, polycarbonate resin, polyphenylene ether resin, and phenol resin. These compounds will be described below.

-Acid-modified polybutadiene Acid-modified polybutadiene is a compound contained in the crosslinked network during the curing reaction of the epoxy resin composition because it has reactivity with the epoxy resin. For this reason, when the acid-modified polybutadiene is used in combination, the obtained cured product can exhibit excellent mechanical strength, heat resistance, and moist heat resistance.

Examples of the acid-modified polybutadiene include those having a butadiene skeleton having a skeleton derived from 1,3-butadiene or 2-methyl-1,3-butadiene. The one derived from 1,3-butadiene includes one having a structure of 1,2-vinyl type, 1,4-trans type, 1,4-cis type, or one having two or more of these structures. Can be mentioned. Those derived from 2-methyl-1,3-butadiene have a structure of any of 1,2-vinyl type, 3,4-vinyl type, 1,4-cis type, and 1,4-trans type And those having two or more of these structures.

The acid-modified component of the acid-modified polybutadiene is not particularly limited, and examples thereof include unsaturated carboxylic acids. As the unsaturated carboxylic acid, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride are preferable, itaconic anhydride and maleic anhydride are preferable, and maleic anhydride is more preferable from the viewpoint of reactivity. .

The content of the unsaturated carboxylic acid in the acid-modified polybutadiene is composed of the acid-modified polybutadiene derived from 1,3-butadiene from the viewpoint of reactivity with the epoxy resin (a) and the polyol compound (c). In this case, the acid value is preferably 5 mgKOH / g to 400 mgKOH / g, more preferably 20 mgKOH / g to 300 mgKOH / g, and further preferably 50 mgKOH / g to 200 mgKOH / g.

When the acid value is 5 mgKOH / g or more, the reactivity with the epoxy resin and the like is excellent, and the obtained cured product has improved heat resistance and moist heat resistance. On the other hand, when the acid value is 400 mgKOH / g or less, mechanical strength such as elongation characteristics is improved in the obtained cured product by appropriately reacting with an epoxy resin or the like.

Further, the unsaturated carboxylic acid component may be copolymerized in the acid-modified polybutadiene, and its form is not limited. Examples thereof include random copolymerization, block copolymerization, and graft copolymerization (graft modification).

The average molar mass of the acid-modified polybutadiene is preferably 1,000 to 8,000, more preferably 2,000 to 7,000 when the acid-modified polybutadiene is composed of 1,3-butadiene. Is more preferable. When the acid-modified polybutadiene is composed of one derived from 2-methyl-1,3-butadiene, it is preferably 1,000 to 60,000, more preferably 15,000 to 40,000. . The average molar mass can be measured using gel permeation chromatography (GPC).

The acid-modified polybutadiene is obtained by modifying polybutadiene with an unsaturated carboxylic acid, but a commercially available product may be used as it is. Examples of commercially available products include maleic anhydride-modified liquid polybutadiene (Polyvest MA75, Polyvest EP MA120, etc.) manufactured by Evonik Degussa, and maleic anhydride-modified polyisoprene (LIR-403, LIR-410) manufactured by Kuraray. can do.

As the acid-modified polybutadiene, the total mass of the epoxy resin, acid anhydride, and acid-modified polybutadiene in the epoxy resin composition is 100 parts by mass from the viewpoint that the elongation, heat resistance, and heat-and-moisture resistance of the cured product obtained are good. , It is preferably contained in a proportion of 1 to 40 parts by mass, more preferably 3 to 30 parts by mass.

-Polyethersulfone resin Polyethersulfone resin is a thermoplastic resin, and is not included in the crosslinked network in the curing reaction of epoxy resin, but in the cured product obtained by the excellent modifier effect having high Tg Furthermore, excellent mechanical strength and heat resistance can be expressed.

In addition, as the polyether sulfone resin, the total mass of the epoxy resin, the acid anhydride, and the polyether sulfone resin in the epoxy resin composition is 100 mass from the viewpoint that the mechanical strength and heat resistance of the obtained cured product are good. Parts, preferably 1 to 30 parts by weight, more preferably 3 to 20 parts by weight.

Polycarbonate resin As the polycarbonate resin, for example, a polycondensate of a divalent or bifunctional phenol and a carbonyl halide, or a divalent or bifunctional phenol and a carbonic acid diester was polymerized by a transesterification method. Things.

Here, examples of the divalent or bifunctional phenol used as a raw material for the polycarbonate resin include 4,4′-dihydroxybiphenyl, bis (4-hydroxyphenyl) methane, and 1,1-bis (4-hydroxyphenyl). Ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, Bis (4-hydroxyphenyl) ketone, hydroquinone, resorcin, Tekoru, and the like. Among these divalent phenols, bis (hydroxyphenyl) alkanes are preferable, and those using 2,2-bis (4-hydroxyphenyl) propane as the main raw material are particularly preferable.

On the other hand, examples of the carbonyl halide or carbonic acid diester to be reacted with a divalent or bifunctional phenol include, for example, phosgene; dihaloformate of dihydric phenol, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate. And diaryl carbonates such as: aliphatic carbonate compounds such as dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, dibutyl carbonate, diamyl carbonate, and dioctyl carbonate.

In addition, the polycarbonate resin may have a branched structure in addition to the polymer chain having a linear molecular structure. Such a branched structure includes 1,1,1-tris (4-hydroxyphenyl) ethane, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene as a raw material component. , Phloroglucin, trimellitic acid, isatin bis (o-cresol) and the like.

Polyphenylene ether resin Examples of polyphenylene ether resins include poly (2,6-dimethyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-14-phenylene) ether, and poly (2,6- Diethyl-1,4-phenylene) ether, poly (2-ethyl-6-n-propyl-1,4-phenylene) ether, poly (2,6-di-n-propyl-1,4-phenylene) ether, Poly (2-methyl-6-n-butyl-1,4-phenylene) ether, poly (2-ethyl-6-isopropyl-1,4-phenylene) ether, poly (2-methyl-6-hydroxyethyl-1) , 4-phenylene) ether and the like.

Of these, poly (2,6-dimethyl-1,4-phenylene) ether is preferable, and 2- (dialkylaminomethyl) -6-methylphenylene ether unit or 2- (N-alkyl-N-phenylaminomethyl)- Polyphenylene ether containing a 6-methylphenylene ether unit or the like as a partial structure may be used.

In the polyphenylene ether resin, a reactive functional group such as a carboxyl group, an epoxy group, an amino group, a mercapto group, a silyl group, a hydroxyl group, or an anhydrous dicarboxyl group is introduced into the resin structure by any method such as graft reaction or copolymerization. Modified polyphenylene ether resins can also be used as long as the object of the present invention is not impaired.

-Phenolic resin Examples of the phenolic resin include a resol type phenolic resin, a novolac type phenolic resin, and the like, a phenol aralkyl resin, a polyvinylphenol resin, a triazine modified phenol novolac resin modified with melamine or benzoguanamine, and the like.

The epoxy resin composition of the present invention contains a polycarbonate resin or a polyphenylene ether resin as described above, so that the cured product obtained can exhibit better mechanical strength, and contains a phenol resin as described above. By doing, in the hardened | cured material obtained, the more outstanding flame retardance can be expressed now.

The epoxy resin composition of the present invention can contain a flame retardant / flame retardant aid, a filler, an additive, and an organic solvent as long as the effects of the present invention are not impaired. The order of blending when producing the epoxy resin composition is not particularly limited as long as the effect of the present invention can be achieved. That is, all the components may be mixed and used in advance, or may be mixed and used in an appropriate order. Moreover, the compounding method can knead | mix and manufacture using kneading machines, such as an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer, for example. Below, the various members which can be contained in the epoxy resin composition of this invention are demonstrated.

Flame Retardant / Flame Retardant Auxiliary The epoxy resin composition of the present invention may 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, and organic metal salt flame retardants. The flame retardants may be used alone or in combination, and a plurality of flame retardants of the same system may be used, or different types of flame retardants may be used in combination.

As the phosphorus flame retardant, either inorganic or organic can be used. Examples of the inorganic compounds include red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate, ammonium phosphates such as ammonium polyphosphate, and inorganic nitrogen-containing phosphorus compounds such as phosphate amide. .

The red phosphorus is preferably subjected to a surface treatment for the purpose of preventing hydrolysis and the like. Examples of the surface treatment method include (i) magnesium hydroxide, aluminum hydroxide, zinc hydroxide, water A method of coating with an inorganic compound such as titanium oxide, bismuth oxide, bismuth hydroxide, bismuth nitrate or a mixture thereof; (ii) an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide; and A method of coating with a mixture of a thermosetting resin such as a phenol resin, (iii) thermosetting of a phenol resin or the like on a coating of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, or titanium hydroxide For example, a method of double coating with a resin may be used.

Examples of the organic phosphorus compound include, for example, general-purpose organic phosphorus compounds such as phosphate ester compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phospholane compounds, organic nitrogen-containing phosphorus compounds, and 9,10- Dihydro-9-oxa-10-phosphaphenanthrene = 10-oxide, 10- (2,5-dihydrooxyphenyl) -10H-9-oxa-10-phosphaphenanthrene = 10-oxide, 10- (2,7 And cyclic organophosphorus compounds such as -dihydrooxynaphthyl) -10H-9-oxa-10-phosphaphenanthrene = 10-oxide.

In addition, when using the phosphorous flame retardant, the phosphorous flame retardant may be used in combination with hydrotalcite, magnesium hydroxide, boric compound, zirconium oxide, black dye, calcium carbonate, zeolite, zinc molybdate, activated carbon, etc. Good.

Examples of the nitrogen-based flame retardant include triazine compounds, cyanuric acid compounds, isocyanuric acid compounds, and phenothiazines, and triazine compounds, cyanuric acid compounds, and isocyanuric acid compounds are preferable.

Examples of the triazine compound include melamine, acetoguanamine, benzoguanamine, melon, melam, succinoguanamine, ethylene dimelamine, melamine polyphosphate, triguanamine, and the like, for example, guanylmelamine sulfate, melem sulfate, melam sulfate, etc. Examples thereof include an aminotriazine sulfate compound, aminotriazine-modified phenol resin, and aminotriazine-modified phenol resin further modified with tung oil, isomerized linseed oil, and the like.

Specific examples of the cyanuric acid compound include cyanuric acid and melamine cyanurate.

The amount of the nitrogen-based flame retardant is appropriately selected depending on the type of the nitrogen-based flame retardant, the other components of the epoxy resin composition, and the desired degree of flame retardancy. It is preferable to mix in an amount of 0.05 to 10 parts by mass in 100 parts by mass of the epoxy resin composition containing all of the agent, non-halogen flame retardant and other fillers and additives. It is preferable to blend in the range of 1 to 5 parts by mass.

Further, when using the nitrogen-based flame retardant, a metal hydroxide, a molybdenum compound or the like may be used in combination.

The silicone flame retardant is not particularly limited as long as it is an organic compound containing a silicon atom, and examples thereof include silicone oil, silicone rubber, and silicone resin.

The amount of the silicone flame retardant is appropriately selected according to the type of the silicone flame retardant, the other components of the epoxy resin composition, and the desired degree of flame retardancy. It is preferable to blend in the range of 0.05 to 20 parts by mass in 100 parts by mass of the epoxy resin composition containing all of the agent, non-halogen flame retardant and other fillers and additives. Moreover, when using the said silicone type flame retardant, you may use a molybdenum compound, an alumina, etc. together.

Examples of the inorganic flame retardant include metal hydroxide, metal oxide, metal carbonate compound, metal powder, boron compound, and low melting point glass.

Specific examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, zirconium hydroxide and the like.

Specific examples of the metal oxide include, for example, zinc molybdate, molybdenum trioxide, zinc stannate, tin oxide, aluminum oxide, iron oxide, titanium oxide, manganese oxide, zirconium oxide, zinc oxide, molybdenum oxide, and cobalt oxide. Bismuth oxide, chromium oxide, nickel oxide, copper oxide, tungsten oxide and the like.

Specific examples of the metal carbonate compound include zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, basic magnesium carbonate, aluminum carbonate, iron carbonate, cobalt carbonate, and titanium carbonate.

Specific examples of the metal powder include aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, and tin.

Specific examples of the boron compound include zinc borate, zinc metaborate, barium metaborate, boric acid, and borax.

Specific examples of the low-melting-point glass include, for example, Shipley (Bokusui Brown), hydrated glass SiO ₂ —MgO—H ₂ O, PbO—B ₂ O ₃ system, ZnO—P ₂ O ₅ —MgO system, P ₂ O ₅ —B ₂ O ₃ —PbO—MgO system, P—Sn—O—F system, PbO—V ₂ O ₅ —TeO ₂ system, Al ₂ O ₃ —H ₂ O system, lead borosilicate system, etc. The glassy compound can be mentioned.

The blending amount of the inorganic flame retardant is appropriately selected according to the type of the inorganic flame retardant, the other components of the epoxy resin composition, and the desired degree of flame retardancy. For example, epoxy resin, cured It is preferable to mix in an amount of 0.05 to 20 parts by mass in 100 parts by mass of the epoxy resin composition containing all of the agent, non-halogen flame retardant and other fillers and additives. It is preferable to blend in the range of 5 to 15 parts by mass.

Examples of the organic metal salt flame retardant include ferrocene, acetylacetonate metal complex, organic metal carbonyl compound, organic cobalt salt compound, organic sulfonic acid metal salt, metal atom and aromatic compound or heterocyclic compound or an ionic bond or Examples thereof include a coordinated compound.

The amount of the organometallic salt-based flame retardant is appropriately selected depending on the type of the organometallic salt-based flame retardant, the other components of the epoxy resin composition, and the desired degree of flame retardancy. It is preferably blended in the range of 0.005 to 10 parts by mass in 100 parts by mass of the epoxy resin composition containing all of the epoxy resin, curing agent, non-halogen flame retardant and other fillers and additives. .

-Filler The epoxy resin composition of the present invention may contain a filler. When the epoxy resin composition of the present invention contains a filler, excellent mechanical properties can be expressed in the obtained cured product.

Examples of fillers include titanium oxide, glass beads, glass flakes, glass fibers, calcium carbonate, barium carbonate, calcium sulfate, barium sulfate, potassium titanate, aluminum borate, magnesium borate, fused silica, crystalline silica, alumina, and nitriding. Examples thereof include fibrous reinforcing agents such as silicon, aluminum hydroxide, kenaf fibers, carbon fibers, alumina fibers, and quartz fibers, and non-fibrous reinforcing agents. These may be used individually by 1 type, or may use 2 or more types together. Moreover, these may be coat | covered with organic substance, an inorganic substance, etc.

Also, when glass fiber is used as the filler, it can be selected from long fiber type roving, short fiber type chopped strand, milled fiber, and the like. It is preferable to use a glass fiber that has been surface-treated for the resin used. By blending the filler, the strength of the incombustible layer (or carbonized layer) generated during combustion can be further improved. The incombustible layer (or carbonized layer) once generated during combustion is less likely to be damaged, can exhibit stable heat insulation ability, and a greater flame retardant effect can be obtained. Further, high rigidity can be imparted to the material.

-Additive The epoxy resin composition of this invention may contain the additive. When the epoxy resin composition of the present invention contains an additive, other properties such as rigidity and dimensional stability are improved in the obtained cured product. Examples of additives include plasticizers, antioxidants, UV absorbers, stabilizers such as light stabilizers, antistatic agents, conductivity-imparting agents, stress relaxation agents, mold release agents, crystallization accelerators, and hydrolysis inhibitors. Agent, lubricant, impact imparting agent, slidability improver, compatibilizer, nucleating agent, reinforcing agent, reinforcing agent, flow regulator, dye, sensitizer, coloring pigment, rubbery polymer, thickener It is also possible to add an anti-settling agent, an anti-sagging agent, an antifoaming agent, a coupling agent, an antirust agent, an antibacterial / antifungal agent, an antifouling agent, a conductive polymer and the like.

-Organic solvent The epoxy resin composition of this invention may contain the organic solvent, when manufacturing a fiber reinforced resin molded article using a filament winding method. Examples of organic solvents that can be used here include methyl ethyl ketone acetone, dimethyl formamide, methyl isobutyl ketone, methoxy propanol, cyclohexanone, methyl cellosolve, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, etc. Can be appropriately selected depending on the application.

<Use of epoxy resin composition>
The epoxy resin composition of the present invention has a low viscosity, has a sufficient pot life, and can exhibit excellent heat resistance and fracture toughness in the resulting cured product. It can be used for molded products, cured products and the like. These will be described below.

1. Fiber Reinforced Composite Material The fiber reinforced composite material of the present invention is a material in a state before curing after the reinforcing fiber is impregnated with the epoxy resin composition. Here, the reinforced fiber may be any of a twisted yarn, an untwisted yarn, or a non-twisted yarn, but the untwisted yarn and the untwisted yarn are preferable because they have excellent formability in the fiber-reinforced composite material. Furthermore, the form of a reinforced fiber can use what the fiber direction arranged in one direction, and a textile fabric. The woven fabric can be freely selected from plain weaving, satin weaving, and the like according to the site and use. Specifically, because of excellent mechanical strength and durability, carbon fiber, glass fiber, aramid fiber, boron fiber, alumina fiber, silicon carbide fiber and the like can be mentioned, and two or more of these can be used in combination. . Among these, carbon fiber is preferable from the viewpoint that the strength of the molded product is particularly good. As the carbon fiber, various types such as polyacrylonitrile-based, pitch-based, and rayon-based can be used.

The method for obtaining the fiber reinforced composite material from the epoxy resin composition of the present invention is not particularly limited. For example, the components constituting the epoxy resin composition are uniformly mixed to adjust the varnish, and then obtained as described above. A method of immersing unidirectional reinforcing fibers in which the reinforcing fibers are aligned in one direction in the varnish (the state before curing by the pultrusion method and the filament winding method), and setting the woven fabric of reinforcing fibers in a concave shape, Thereafter, after sealing with a convex mold, a method of injecting resin and impregnating with pressure (state before curing by the RTM method) and the like can be mentioned.

The fiber reinforced composite material of the present invention is not necessarily impregnated with the epoxy resin composition up to the inside of the fiber bundle, and may be an embodiment in which the epoxy resin composition is localized near the surface of the fiber. good.

Furthermore, in the fiber reinforced composite material of the present invention, the volume content of the reinforced fiber with respect to the total volume of the fiber reinforced composite material is preferably 40% to 85%, and in the range of 50% to 70% from the viewpoint of strength. More preferably. When the volume content is less than 40%, the cured product obtained when the content of the epoxy resin composition is too high is insufficient in flame retardancy, or required for a fiber-reinforced composite material excellent in specific modulus and specific strength. Some characteristics may not be satisfied. On the other hand, if the volume content exceeds 85%, the adhesion between the reinforcing fiber and the resin composition may be lowered.

2. Fiber-reinforced resin molded product The fiber-reinforced resin molded product of the present invention is a molded product having reinforcing fibers and a cured product of an epoxy resin composition, and is obtained by thermosetting a fiber-reinforced composite material. Specifically, the fiber-reinforced resin molded article of the present invention preferably has a volume content of reinforcing fibers in the fiber-reinforced molded article in the range of 40% to 85%, and 50% to 70% from the viewpoint of strength. A range is particularly preferred. Examples of such fiber reinforced resin molded products include front subframes, rear subframes, front pillars, center pillars, side members, cross members, side sills, roof rails, propeller shafts and other automotive parts, electric wire cable core members, Examples include pipe materials for subsea oil fields, roll / pipe materials for printing presses, robot forks, primary structural materials for aircraft, and secondary structural materials.

The method for obtaining a fiber-reinforced molded product from the epoxy resin composition of the present invention is not particularly limited, but it is preferable to use a pultrusion method (pultrusion method), a filament winding method, an RTM method, or the like. The pultrusion method (pultrusion method) is a method in which a fiber reinforced composite material is introduced into a mold, heated and cured, and then pulled out with a drawing device to form a fiber reinforced resin molded product. Is a method in which a fiber reinforced composite material (including unidirectional fibers) is wound around an aluminum liner or a plastic liner while being rotated and then heat cured to form a fiber reinforced resin molded product. Is a method using two types of molds, a concave mold and a convex mold, in which a fiber reinforced composite material is heated and cured in the mold to mold a fiber reinforced resin molded product. In addition, when molding a large product or a fiber reinforced resin molded product having a complicated shape, it is preferable to use the RTM method.

As the molding conditions of the fiber reinforced resin molded product, the fiber reinforced composite material is preferably thermoset in a temperature range of 50 ° C. to 250 ° C., more preferably in a temperature range of 70 ° C. to 220 ° C. . If the molding temperature is too low, sufficient fast curability may not be obtained. Conversely, if the molding temperature is too high, warping due to thermal strain may be likely to occur. As other molding conditions, the fiber reinforced composite material is pre-cured at 50 ° C. to 100 ° C. to form a tack-free cured product, and further processed at a temperature condition of 120 ° C. to 200 ° C. The method of hardening can be mentioned.

Other methods for obtaining a fiber reinforced molded product from the epoxy resin composition of the present invention include a hand lay-up method and a spray-up method in which a fiber aggregate is laid on a mold and the varnish and fiber aggregate are laminated in layers. Using either male or female type, base material made of reinforcing fiber is piled up while impregnating varnish, molded, covered with a flexible mold that can apply pressure to the molded product, and hermetically sealed Examples include (vacuum) vacuum bag method for molding, and SMC press method in which a varnish containing reinforcing fibers is formed into a sheet shape by compression molding with a mold.

3. Cured product As a method of obtaining a cured product from the epoxy resin composition of the present invention, it is sufficient to comply with a general method for curing an epoxy resin composition, for example, the heating temperature condition depends on the type and use of the curing agent to be combined, What is necessary is just to select suitably. For example, a method of heating the epoxy resin composition in a temperature range of room temperature to about 250 ° C. can be mentioned. As a molding method, a general method of an epoxy resin composition can be used, and a condition peculiar to the epoxy resin composition of the present invention is not particularly necessary.

Next, the present invention will be specifically described with reference to examples and comparative examples. In the following, “part” and “%” are based on mass unless otherwise specified.

Examples 1 to 5 and Comparative Examples 1 to 4
According to the composition shown in Table 1 below, the epoxy resin, acid anhydride, polyol compound and curing accelerator were placed in a kettle and stirred to homogenize the epoxy resin compositions of Examples 1 to 5 and Comparative Examples 1 to 4. Obtained. Next, the epoxy resin composition obtained above was poured into a mold that had been processed to have a thickness corresponding to the evaluation item, and molded for 10 minutes at 160 ° C. to obtain a cured product.

The epoxy resin, acid anhydride, polyol compound, and curing accelerator used in Examples and Comparative Examples are as follows.
Epoxy resin (a)
A-1: BPA type epoxy resin EPICLON 850S (manufactured by DIC Corporation, average functional group number: 2.0)
A-2: BPF type epoxy resin EPICLON 830S (manufactured by DIC Corporation, average functional group number: 2.1)
A-3: phenol novolac epoxy resin EPICLON N-740 (manufactured by DIC Corporation, average functional group number: 3.7)

Acid anhydride (b)
B-1: Tetrahydromethylphthalic anhydride EPICLON B-570H (manufactured by DIC Corporation)

Polyol compound (c)
C-1: 2,2-bis (4-polyoxyethyleneoxyphenyl) propane BA-2 glycol (Hydroxyl equivalent 165 g / eq, manufactured by Nippon Emulsifier Co., Ltd.)
C-2: 2,2-bis (4-polyoxyethyleneoxyphenyl) propane BA-P2 glycol (hydroxyl equivalent 178 g / eq, manufactured by Nippon Emulsifier Co., Ltd.)
C-3: 2,2-bis (4-polyoxyethyleneoxyphenyl) propane BA-P13U glycol (manufactured by Nippon Emulsifier Co., Ltd., hydroxyl equivalent 468 g / eq)
C-4: polytetramethylene glycol PTMG-1000 (manufactured by Mitsubishi Chemical Corporation, hydroxyl equivalent: 500 g / eq)
C-5: Polyethylene glycol PEG-2000 (manufactured by Sanyo Chemical Industries, Ltd., hydroxyl group equivalent 1000 g / eq)

Curing accelerator (d)
D-1: 1,2-dimethylimidazole 1,2DMZ (manufactured by Shikoku Chemicals Co., Ltd.)

<Measurement of viscosity>
The viscosity at 25 ° C. of the epoxy resin composition obtained above was measured using a viscometer (TOKI SANGYO CO. LTD. VISCOMETER TV-22).

<Measurement of pot life>
The initial viscosity of the epoxy resin composition obtained above is that the viscosity after 3 hours of storage at 25 ° C. does not exceed 2 times, the pot life is good (◯), the one that exceeds 2 times is poor pot life (×) It was.

<Measurement of fracture toughness value>
The obtained cured product having a thickness of 6 mm was cut into a width of 12 mm and a length of 55 mm using a diamond cutter, and a predetermined pre-crack was made using a diamond cutter and a razor. Using specimen 1, the fracture toughness value (K _1C ) was measured according to ASTM D5045. In addition, Shimadzu Corporation autograph AG-IS was used for the measurement.

<Measurement of heat resistance>
The cured product having a thickness of 2 mm obtained above was cut into a width of 5 mm and a length of 50 mm with a diamond cutter. Next, using a viscoelasticity measuring device (“DS6100” manufactured by SII NanoTechnology Co., Ltd.), the dynamic viscoelasticity of the test piece 2 due to double-end bending is measured, and the temperature (glass transition point) at which tan δ is maximized. Temperature). The results are shown in Table 1. The measurement conditions for the dynamic viscoelasticity measurement were temperature range: room temperature to 260 ° C., heating rate: 3 ° C./min, frequency: 1 Hz, strain amplitude: 10 μm.

Claims

An epoxy resin (a) having an average functional group number of 1.5 to 2.2, an acid anhydride (b), two or more alcoholic hydroxyl groups in the molecule, and a hydroxyl group equivalent of 30 g / eq to 650 g / An epoxy resin composition comprising a polyol compound (c) which is eq, and a curing accelerator (d).
When the total mass of the epoxy resin (a), the acid anhydride (b), the polyol compound (c), and the curing accelerator (d) is 100 parts by mass, the curing accelerator (d 2) The epoxy resin composition according to claim 1, comprising 0.1 to 5.0 parts by mass.
When the diol compound (c) has a total mass of 100 parts by mass with the epoxy resin (a), the acid anhydride (b), and the curing accelerator (d), 1 to 20 parts by mass. The epoxy resin composition according to claim 1 or 2 contained in a proportion.
The epoxy resin composition according to any one of claims 1 to 3, wherein the epoxy resin (a) is a bisphenol type epoxy resin.
The epoxy resin composition according to claim 4, wherein the bisphenol type epoxy resin is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin.
The epoxy resin composition according to any one of claims 1 to 5, wherein the polyol compound (c) is a compound having at least an aromatic ring or a cyclo ring in the molecule.
The epoxy resin composition according to claim 6, wherein the polyol compound (c) is a compound having at least a polyalkylene oxide in the molecule.
The epoxy resin composition according to claim 7, wherein an average value of the number of repeating units of the alkylene oxide constituting the polyalkylene oxide is 2 to 18.
The epoxy resin composition according to claim 7 or 8, wherein the polyalkylene oxide is polyethylene oxide or polypropylene oxide.
A cured product obtained by curing the epoxy resin composition according to any one of claims 1 to 9.
A fiber-reinforced composite material comprising the epoxy resin composition according to any one of claims 1 to 9 and reinforcing fibers as essential components.
The fiber-reinforced composite material according to claim 11, wherein the volume content of the reinforcing fibers is in the range of 40% to 85%.
A fiber-reinforced resin molded product comprising the cured product of claim 10 and reinforcing fibers as essential components.
The fiber-reinforced resin molded article according to claim 13, wherein the volume content of the reinforcing fibers is in the range of 40% to 85%.
The fiber-reinforced resin molded product according to claim 13 or 14, which is a core member of an electric cable.
A method for producing a fiber-reinforced resin molded article, wherein the fiber-reinforced composite material according to claim 11 or 12 is thermoset.
A method for producing a fiber-reinforced resin molded article, in which the fiber-reinforced composite material according to claim 11 or 12 is pultruded.