JP2016044246A - Epoxy resin composition, prepreg, fiber- reinforced composite material and structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition capable of providing a fiber reinforced composite material which is excellent in curability, and has excellent fire resistance even not containing a halogen-based fire retardant, red phosphorus, phosphoester or a phosphazene compound and is excellent in heat resistance, and to provide a prepreg, and the fiber reinforced composite material and a structure each obtained by using the prepreg.SOLUTION: There is provided the epoxy resin composition containing a compound (A) represented by the general formula (a), a bifunctional epoxy resin (B), a trifunctional or more epoxy resin (C) and an epoxy resin curing agent (D) with the content of the trifunctional or more epoxy resin (C) being 10 to 95 pts.mass based on total 100 pts.mass of the bifunctional epoxy resin (B) and the trifunctional or more epoxy resin (C).SELECTED DRAWING: None

Description

  The present invention relates to an epoxy resin composition, a prepreg, a fiber reinforced composite material, and a structure.

  In particular, the present invention relates to an epoxy resin composition for obtaining a fiber-reinforced composite material (hereinafter referred to as “FRP”) suitable for use in aircraft materials as well as general industrial use and the use thereof.

  A fiber reinforced composite material combining a resin and a reinforced fiber is used in various applications because it is excellent in lightness, rigidity, impact resistance and the like. In particular, carbon fiber reinforced composite materials are lightweight, high in strength, and high in rigidity. Therefore, they are used in a wide range of fields such as sports and leisure applications such as fishing rods and golf shafts, automobile applications, and aircraft applications. In recent years, in addition to the mechanical properties of carbon fiber reinforced composite materials, it has also been used as a housing for electronic and electrical devices such as notebook personal computers, taking advantage of the electromagnetic shielding properties of carbon fibers.

  Fiber reinforced composite materials may be required flame retardant performance in various applications. For example, electronic and electrical equipment and aircraft structures are required to have flame retardancy because ignition due to heat generation may cause a fire.

  As a method of making a fiber reinforced composite material flame-retardant, a method of adding a brominated epoxy resin to a matrix resin composition has been widely used. However, in recent years, red phosphorus and phosphate ester compounds have been used as a flame retardant alternative to adding brominated epoxy resins from the viewpoint of the burden on the human body and the environment of harmful substances generated during combustion of halogen-containing resin compositions. A method of adding to a resin composition (for example, Patent Document 1) and a method of adding a phosphazene compound to an epoxy resin composition have become mainstream.

International Publication No. 2005/082982 Pamphlet

However, the method of adding red phosphorus, phosphate ester compound, phosphazene compound, etc. as a flame retardant,
1) When the amount of the flame retardant added is large, the mechanical strength of the resulting fiber-reinforced composite material decreases.
2) The storage stability of the resin composition tends to decrease due to the addition of the flame retardant.
3) The flame retardant gradually exudes (bleeds out) from the fiber reinforced composite material over a long period of time.
4) Red phosphorus and phosphate ester compounds are easily hydrolyzed in fiber reinforced composite materials.
5) When there is much addition amount of a phosphate ester compound or a phosphazene compound, the glass transition temperature (Tg) of the hardened | cured material of a resin composition will fall (the heat resistance of hardened | cured material will become low),
There are problems such as.

  Therefore, the flame retardance performance that can be imparted to the fiber-reinforced composite material is limited by the above-described method, and the stability of the resin composition itself as a material is low. In particular, the method using red phosphorus or a phosphate ester compound is difficult to use in the fields of printed wiring boards and electronic materials that require high insulation and water resistance due to the problem 4).

  The present invention has been made in view of the above circumstances, and is an epoxy resin composition capable of producing a fiber-reinforced composite material having excellent curability and excellent flame retardancy and heat resistance, and a prepreg, and the prepreg. It aims at providing the fiber reinforced composite material and structure which are obtained.

  As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by using two or more types of epoxy resins containing a specific polyphosphonate compound and having different numbers of functional groups, resulting in the present invention. .

That is, the present invention is as follows.
[1] A compound (A) represented by the following formula (a), a bifunctional epoxy resin (B), a trifunctional or higher functional epoxy resin (C), and an epoxy resin curing agent (D), the trifunctional or higher functional The epoxy resin composition whose content of an epoxy resin (C) is 10-95 mass parts with respect to a total of 100 mass parts of the said bifunctional epoxy resin (B) and a trifunctional or more than trifunctional epoxy resin (C).

... (a)
(In the above formula (a), n represents an integer of 2 to 500.)
[2] The epoxy resin composition according to [1], wherein the content of the compound (A) is such that the phosphorus atom content in the epoxy resin composition is 0.05 to 3.5% by mass. .
[3] The epoxy resin composition according to [1] or [2], further containing a metal hydroxide (F).
[4] The epoxy resin composition according to [3], wherein the metal hydroxide (F) is aluminum hydroxide.
[5] A prepreg obtained by impregnating a reinforcing fiber assembly with the epoxy resin composition according to any one of [1] to [4].
[6] The prepreg according to [5], including carbon fibers as reinforcing fibers constituting the reinforcing fiber aggregate.
[7] A fiber-reinforced composite material obtained by curing the prepreg according to [5] or [6].
[8] The fiber-reinforced composite material according to [7], wherein the flame retardancy when the thickness is 1 mm is UL-94V and is V-0 or V-1.
[9] The fiber-reinforced composite material according to [7], wherein the flame retardancy when the thickness is 1 mm is FAR 25.853, a-1 Part IV.
[10] A structure partly or entirely composed of the fiber-reinforced composite material according to any one of [7] to [9].

  By using the epoxy resin composition of the present invention, it is possible to provide a prepreg capable of producing a fiber-reinforced composite material having excellent curability and flame retardancy and heat resistance, and by using the prepreg, excellent as described above. Fiber reinforced composite materials and structures can be provided.

  Hereinafter, the present invention will be described in detail.

  In the present invention, the “bifunctional epoxy resin” means a compound having two epoxy groups in the molecule. Hereinafter, the same applies to “a trifunctional or higher functional epoxy resin”.

  The term “epoxy resin” is used as the name of one category of thermosetting resin or the name of the category of a chemical substance called compound having one or more epoxy groups in the molecule. Used in

  The term “epoxy resin composition” means a composition comprising an epoxy resin and a curing agent, and optionally other additives. A cured product obtained by curing the epoxy resin composition may be simply referred to as a “resin cured product”.

≪Epoxy resin composition≫
The epoxy resin composition of the present invention contains the following components (A) to (D) as essential components.

Compound (A) represented by the following formula (a)
Bifunctional epoxy resin (B)
Trifunctional or higher epoxy resin (C)
Epoxy resin curing agent (D)

... (a)
(In the above formula, n represents an integer of 2 to 500.)
<Compound (A) represented by Formula (a)>
The epoxy resin composition of the present invention contains a compound (A) represented by the above formula (a) (hereinafter sometimes referred to as “component (A)”).

  In the formula (a), n is an integer of 2 to 500, preferably an integer of 5 to 450. By setting n to the lower limit value or more, bleeding out of the compound from the fiber-reinforced composite material can be sufficiently prevented, and by setting it to the upper limit value or less, the solubility in the epoxy resin composition is improved. Therefore, it is preferable.

  In the compound represented by the above formula (a), the phosphorus atom is incorporated into the main chain. In other words, since phosphorus atoms are fixed in the molecule by chemical bonds, when an epoxy resin composition containing this is molded, a phosphorus component (in the present invention) is formed on the surface of the molded product (prepreg, fiber reinforced composite material, etc.). (A) component) does not precipitate, the phosphorus component is hardly hydrolyzed, and it becomes a flame retardant resin composition that can provide an excellent molded product.

  (A) As for the phosphorus atom content rate in a component, 1-15 mass% is preferable. By making this phosphorus atom content rate more than the said lower limit, the flame retardance improvement of the hardened | cured material of the said epoxy resin composition becomes easy, and it becomes easy to obtain the fiber reinforced composite material which shows sufficiently high flame retardance. By making this phosphorus atom content rate into the said upper limit or less, the heat resistance of the hardened | cured material of the said epoxy resin composition improves, and it becomes easy to obtain the fiber reinforced composite material which has sufficiently high heat resistance.

  The weight average molecular weight of (A) component is 1000-150,000 normally, Preferably it is 1500-145000, Most preferably, it is 2000-140000. By setting the molecular weight to the upper limit or less, the solubility in the epoxy resin composition is improved, and by setting the molecular weight to the lower limit or more, bleeding out can be sufficiently prevented.

  A commercial item may be used for (A) component, and what was synthesize | combined with the well-known manufacturing method may be used. As a commercial item, NofaHM1100, NofiaOL1001, NofiaOL3001, NofiaOL5000 by FRXpolymers etc. are mentioned, for example.

  In the epoxy resin composition of the present invention, the content of the component (A) is preferably 1 part by mass with respect to 100 parts by mass of the essential epoxy resin (component (B) and component (C)) in the epoxy resin composition. As mentioned above, More preferably, it is 3 mass parts or more, More preferably, it is 5 mass parts or more. Moreover, 60 mass parts or less are preferable, 55 weight parts or less are more preferable, and 50 weight parts or less are especially preferable. By setting it as 5 mass parts or more especially, the more outstanding flame retardance is acquired. Moreover, suitable heat resistance can be provided to resin cured material by setting it as 60 mass parts or less.

  In the epoxy resin composition of the present invention, the content of the component (A) is preferably such that the phosphorus atom content in the epoxy resin composition is 0.05% by mass or more, and 0.2% by mass or more. Is more preferable, and an amount of 0.4% by weight or more is particularly preferable. By setting it as 0.05 mass% or more, the more outstanding flame retardance performance can be provided. Moreover, it is preferable to set it as 3.5 mass% or less, 3.3 mass% or less is further more preferable, and 3.1 mass% or less is especially preferable. By setting it to 3.5% by mass or less, sufficient heat resistance can be imparted to the cured resin.

<Bifunctional epoxy resin (B)>
The epoxy resin composition of the present invention contains a bifunctional epoxy resin (B) (hereinafter sometimes referred to as “component (B)”).

  By containing a bifunctional epoxy resin, the cured product of the epoxy resin composition of the present invention can have a sufficient elongation.

  Examples of the component (B) include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins, dicyclopentadiene type epoxy resins, and epoxy resins obtained by modifying these. However, it is not limited to these. Any of these may be used alone or in combination of two or more.

  Among these, bisphenol F-type epoxy resins can be used particularly suitably because they easily generate char during combustion.

  Commercially available products include jER807 (Mitsubishi Chemical Corporation), jER828 (Mitsubishi Chemical Corporation), GAN (Nippon Kayaku Co., Ltd.), jER630 (Mitsubishi Chemical Corporation), HP4032 (DIC Corporation) )) And the like, but is not limited thereto.

  In the epoxy resin composition of the present invention, the content of the component (B) is usually 10 masses with respect to a total of 100 parts by mass of the essential epoxy resin (component (B) and component (C)) in the epoxy resin composition. Part or more, more preferably 15 parts by weight or more. Moreover, it is 95 mass parts or less normally, Preferably it is 90 mass parts or less, More preferably, it is 85 weight part or less, Most preferably, it is 80 weight part or less. By setting the content to be equal to or higher than the lower limit value, the cured resin product is prevented from becoming brittle, and by setting the content to be equal to or lower than the upper limit value, it is possible to obtain a cured resin product having good heat resistance.

<Trifunctional or higher epoxy resin (C)>
The epoxy resin composition of the present invention contains a trifunctional or higher functional epoxy resin (C) (hereinafter sometimes referred to as “component (C)”).

  By containing a trifunctional or higher functional epoxy resin (hereinafter sometimes simply referred to as “polyfunctional epoxy resin”), the epoxy resin composition of the present invention has a high cross-linking density of the cured resin and improved heat resistance. Has the effect and advantage of

  Examples of the component (C) include phenol novolac type epoxy resins; cresol novolac type epoxy resins; trisphenolmethane type epoxy resins; glycidylamine type epoxy resins such as tetraglycidyldiaminodiphenylmethane and triglycidylaminophenol; tetrakis (glycidyloxyphenyl). ) Glycidyl ether type epoxy resins other than the above, such as ethane and tris (glycidyloxyphenyl) methane; and epoxy resins modified by these, but are not limited thereto.

  Any of these may be used alone or in combination of two or more. Of these, phenol novolac type epoxy resins and cresol novolac type epoxy resins can be particularly preferably used.

  As product names, YDPN-638 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) jER604 (manufactured by Mitsubishi Chemical Corporation), EPON165 (manufactured by Momentive Co., Ltd.), jER630 (manufactured by Mitsubishi Chemical Corporation), jER1032H60 ( Examples include Mitsubishi Chemical Corporation), jER152 (Mitsubishi Chemical Corporation), MY-0500 (Huntsman Corporation), MY-0600 (Huntsman Corporation), and the like. It is not limited.

  In the epoxy resin composition of the present invention, the content of the component (C) is usually 10 masses with respect to a total of 100 parts by mass of the essential epoxy resins (component (B) and component (C)) in the epoxy resin composition. Part or more, more preferably 15 parts by weight or more, and particularly preferably 20 parts by weight or more. By setting it as 10 mass parts or more, the heat resistance of resin cured material becomes favorable. Moreover, it is 95 mass parts or less normally, 90 mass parts or less are preferable, and 85 mass parts or less are more preferable. By setting it as 95 mass parts or less, it can prevent that resin cured material becomes weak.

<Epoxy resin curing agent (D)>
The epoxy resin curing agent (D) (hereinafter sometimes referred to as “component (D)”) may have any structure as long as it can cure the epoxy resin, and a known curing agent is used. Is possible. Specific examples include amine-type curing agents, acid anhydrides, novolak resins, phenolic compounds, mercaptans, Lewis acid amine complexes, onium salts, and the like.

  Among these, amine type curing agents are preferred. Examples of amine-type curing agents include aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone; aliphatic amines; imidazole derivatives; dicyandiamide; tetramethylguanidine; thiourea-added amines; I can do it.

  Among the above, dicyandiamide is preferable in that it can impart a thermal activity type latency to the epoxy resin composition and is excellent in storage stability of the epoxy resin composition.

  Here, the thermal activation type potential means a property that is in a state of low activity at room temperature, but undergoes a phase change or chemical change by giving a certain thermal history, and changes to a state of high activity. To do.

  In the epoxy resin composition of the present invention, when the active hydrogen content of the component (D) is determined, the activity in the component (D) with respect to 1 mol equivalent of the epoxy group in the epoxy resin composition. The amount that hydrogen is 0.4 to 1.2 mol is preferable, and the amount that hydrogen is 0.5 to 0.9 is more preferable. If active hydrogen is 0.4 mol or more with respect to 1 mol of epoxy groups, the epoxy resin contained in an epoxy resin composition can fully be hardened. On the other hand, if the active hydrogen is 1.0 mol or less, the toughness of the cured resin can be increased.

<Curing accelerator (E)>
The epoxy resin composition of this invention may contain a hardening accelerator (E) in the range which does not impair the effect of this invention as needed. The curing accelerator (E) is not particularly limited as long as it accelerates the curing reaction by the epoxy resin curing agent (D) to be used.

  For example, when the epoxy resin curing agent (D) is dicyandiamide, examples of the curing accelerator (E) include 4,4′-methylenebis (phenyldimethylurea) (MBPDMU), 3-phenyl-1,1-dimethylurea (PDMU). ), 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-chloro-4-methylphenyl) -1,1-dimethylurea, 2,4-bis (3,4) Urea derivatives such as 3-dimethylureido) toluene are preferred.

  When the epoxy resin curing agent (D) is an acid anhydride or a novolak resin, a tertiary amine is preferable as the curing accelerator (E).

  When the epoxy resin curing agent (D) is diaminodiphenylsulfone, the curing accelerator (E) includes urea compounds such as imidazole compounds and MBPDMU, or amine complexes such as monoethylamine trifluoride and amine trichloride complexes. preferable.

  Among these, a combination of dicyandiamide and MBPDMU or PDMU is particularly preferable. Examples of commercially available MBPDMU include Technology MDU-11 (manufactured by A & C Catalysts) and omicure 52 (manufactured by PTI Japan). Examples of commercially available products of PDMU include omicure (Omicure) 94 (manufactured by PTI Japan).

  3 mass parts or more are preferable with respect to 100 mass parts of epoxy resin compositions of this invention, and, as for content of a hardening accelerator (E), 5 mass parts or more are more preferable, and 25 mass parts or less are preferable, and 20 mass parts is preferable. The following is more preferable. By setting the curing accelerator (E) to the above lower limit value or more, the curing acceleration effect of the epoxy resin is sufficiently achieved, and by setting the curing accelerator to the above upper limit value or less, good flame retardancy and heat resistance of the cured product are obtained. Can do.

<Metal hydroxide (F)>
The epoxy resin composition of the present invention preferably further contains a metal hydroxide (F).

  The kind of metal hydroxide (F) is not specifically limited, A well-known metal hydroxide can be used as an inorganic flame retardant. Examples of such metal hydroxides include aluminum hydroxide and magnesium hydroxide. Among these, aluminum hydroxide is preferable from the viewpoint of the thermal decomposition temperature and the amount of heat absorbed during decomposition.

  As a metal hydroxide (F), a granular thing is normally used. From the viewpoint of dispersibility, the central particle diameter of the metal hydroxide (F) is preferably 15 μm or less, and more preferably 2.5 μm or less. The central particle diameter is a value measured according to JIS R1629 laser diffraction / scattering method.

  The metal hydroxide (F) may be subjected to a surface treatment as necessary. Examples of the surface treatment include a surface treatment with stearic acid and a surface treatment with a coupling agent.

  A commercially available product may be used as the metal hydroxide (F), or a product synthesized by a known production method may be used. For example, as commercially available aluminum hydroxide, C-303, C-301, C-301N, C-300GT manufactured by Sumitomo Chemical Co., Ltd., Hijilite H-42, H-43 manufactured by Showa Denko KK and the like can be mentioned. Examples of commercially available magnesium hydroxide include Magstar # 5, # 4, # 2 and Echo Mug PZ-1, Z-10 manufactured by Tateho Chemical Industry Co., Ltd.

  When using a metal hydroxide (F), the blending amount is preferably 5% by mass or more, more preferably 10% by mass or more, and 70% by mass or less in 100% by mass of the epoxy resin composition. Preferably, 60 mass% or less is more preferable. By setting the content to be equal to or higher than the above lower limit value, the effect of improving the flame retardancy of the epoxy resin composition is sufficiently exhibited, and when the content is not higher than the upper limit value, the viscosity of the epoxy resin composition is adjusted to an appropriate range. This is preferable from the viewpoint of manufacturing the prepreg, and is preferable because the mechanical properties of the fiber-reinforced composite material can be kept good.

<Other ingredients>
The epoxy resin composition of the present invention may contain a thermoplastic resin (G) within a range that does not impair the effects of the present invention in order to control resin flow during molding and impart toughness to the cured resin.

  Examples of the thermoplastic resin (G) include polyamide, polyester, polycarbonate, polyether sulfone, polyphenylene ether, polyphenylene sulfide, polyether ether ketone, polyether ketone, polyimide, polytetrafluoroethylene, polyether, polyolefin, liquid crystal polymer, Examples include polyarylate, polysulfone, polyacrylonitrile styrene, polystyrene, polyacrylonitrile, polymethyl methacrylate, ABS, AES, ASA, polyvinyl chloride, polyvinyl formal, and phenoxy resin. Any of these may be used alone or in combination of two or more.

  Among these, a phenoxy resin is preferable from the viewpoint of excellent resin flow controllability, curability, flame retardancy of a cured resin, and the like.

  In the epoxy resin composition of the present invention, the compounding amount of the component (G) is preferably 1 part by mass or more, preferably 2 parts by mass or more with respect to 100 parts by mass of the total epoxy resin contained in the epoxy resin composition. Is more preferable, 50 mass parts or less are preferable, and 40 mass parts or less are more preferable. By making the content more than the above lower limit value, the effect of improving physical properties is satisfactorily exhibited, and by making the content not more than the above upper limit value, the heat resistance of the resin cured product and the draping property of the prepreg are preferably kept good. .

  Furthermore, the epoxy resin composition of the present invention may contain various known additives as long as the effects of the present invention are not impaired. Examples of the additive include silicone oils, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffins and other mold release agents, crystalline silica, fused silica, calcium silicate. And powders such as alumina, calcium carbonate, talc and barium sulfate, inorganic fillers such as glass fiber and carbon fiber, colorants such as carbon black and bengara, and silane coupling agents. Any of these may be used alone or in combination of two or more.

<Physical properties of epoxy resin composition>
As described later, the epoxy resin composition of the present invention is preferably impregnated into a reinforcing fiber assembly and applied to the production of a prepreg.

  The viscosity of the epoxy resin composition is such that the viscosity at 60 ° C. is 10 Pa · s or more from the viewpoint of adjusting the tackiness of the surface of the obtained prepreg and controlling the fluidity of the resin during molding (suppression of disturbance of reinforcing fibers). It is preferably 20 Pa · s or more, more preferably 30 Pa · s or more. Further, if the viscosity is too high, the impregnation property to the reinforcing fiber aggregate and the molding processability of the prepreg tend to be reduced, so that it is preferably 3000 Pa · s or less, more preferably 2900 Pa · s or less, particularly preferably 2800 Pa · s or less. preferable. The viscosity of the epoxy resin composition at 60 ° C. is, for example, a rheometer using a 25 mmφ parallel plate, a plate gap of 500 μm, a temperature increase rate of 2 ° C./min, about 1.5 Hz (angular velocity 10 rad / sec). It can be obtained by measuring the amplitude with a maximum stress of 300 Pa.

In addition, the epoxy resin composition of this invention is excellent in sclerosis | hardenability, for example, can be hardened by heating for 10 minutes at 140 degreeC <The preparation method of an epoxy resin composition>
The epoxy resin composition of this invention can be prepared by mixing said each component.

  Examples of a method for mixing each component include a method using a mixer such as a three-roll mill, a planetary mixer, a kneader, a homogenizer, and a homodisper.

≪Prepreg≫
The prepreg of the present invention is obtained by impregnating a reinforcing fiber assembly with the epoxy resin composition of the present invention.

  In the prepreg of the present invention, the content of the epoxy resin composition relative to the total weight of the prepreg (hereinafter referred to as the resin content) is preferably 15 to 50% by mass, more preferably 20 to 45% by mass, Preferably it is 25-40 mass%. By setting the resin content to 15% by mass or more, sufficient adhesion between the reinforcing fiber and the epoxy resin composition can be secured, and by setting the resin content to 50% by mass or less, excellent flame retardancy can be obtained. I can do it.

  The reinforcing fiber constituting the reinforcing fiber assembly is not particularly limited, and may be appropriately selected from those known as reinforcing fibers constituting the fiber-reinforced composite material according to the application. For example, various inorganic fibers or organic fibers such as carbon fiber, aramid fiber, nylon fiber, high-strength polyester fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber can be used. Among these, carbon fiber, aramid fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber are preferable from the viewpoint of flame retardancy, and carbon fiber is particularly preferable from the viewpoint of excellent specific strength, specific elasticity, and electromagnetic wave shielding properties.

  The carbon fiber preferably has a strand tensile strength measured according to JIS R7601 (1986) of 1.0 to 9.0 GPa and a strand tensile elastic modulus of 150 to 1000 GPa, a strand tensile strength of 1.5 to 9.0 GPa, A strand tensile modulus of 200 to 1000 GPa is more preferable.

  There is no restriction | limiting in particular in the form of a reinforced fiber assembly, What is normally used as a base material of a prepreg can be used. For example, reinforcing fibers may be aligned in one direction, and may be a woven fabric, a non-woven fabric, or a non-crimp fabric.

≪Fiber reinforced composite material≫
The fiber-reinforced composite material of the present invention is obtained by curing the prepreg of the present invention.

  Since the fiber-reinforced composite material of the present invention is excellent in flame retardancy, heat resistance, electromagnetic wave shielding properties, mechanical properties, and the like, it is preferable to include carbon fibers as reinforcing fibers.

  The fiber-reinforced composite material of the present invention can be produced by a known method using the prepreg of the present invention, and examples thereof include a method of press molding using a mold.

  Since the fiber-reinforced composite material of the present invention contains the cured product of the epoxy resin composition of the present invention, it can achieve excellent flame retardancy without containing a halogen-based flame retardant, red phosphorus, or phosphate ester. For example, when a fiber reinforced composite material molded plate having a thickness of about 1 mm is used, flame retardancy of V-0 or V-1 level can be achieved with UL-94V. In particular, by containing the above-mentioned component (F), higher flame retardancy can be achieved, and specifically, Pass can be achieved according to the FAR 25.853, a-1 Part IV standard.

  Therefore, the fiber reinforced composite material of the present invention is useful in applications that require high flame retardancy. Such applications include casings for electrical and electronic equipment, interior materials for aircraft and automobiles, and the like.

  Moreover, the fiber-reinforced composite material of the present invention also has good heat resistance. Therefore, the fiber-reinforced composite material of the present invention is highly useful in applications requiring excellent heat resistance in addition to high flame retardancy, and is particularly suitable for use in electrical and electronic equipment casings.

≪Structure≫
The structure of the present invention is a part or all of the fiber-reinforced composite material of the present invention.

  Therefore, the structure of the present invention may be composed of the fiber-reinforced composite material of the present invention, and the fiber-reinforced composite material of the present invention and other materials (metal, injection-molded thermoplastic resin member, etc.) It may be comprised from these.

  Next, the present invention will be described in more detail with reference to examples.

  The raw materials (resin etc.) used by the Example and the comparative example are shown below.

<Raw material>
[(A) component]
Nofia HM1100: molecular weight 50000, phosphorus atom content 10.8% by mass, manufactured by FRXpolymers.
[Component (B)]
jER828: Liquid bisphenol A type epoxy resin, epoxy equivalent 189 g / eq, manufactured by Mitsubishi Chemical Corporation.

jER807: Liquid bisphenol F type epoxy resin, epoxy equivalent 168 g / eq, manufactured by Mitsubishi Chemical Corporation.
[Component (C)]
YDPN-638: Liquid phenol novolac type epoxy resin, epoxy equivalent 180 g / eq, manufactured by Nippon Steel Chemical Co., Ltd.

Epon165: Solid cresol novolac type epoxy resin, epoxy equivalent 220 g / eq, manufactured by Mitsubishi Chemical Corporation.
[(D) component]
DICY15: Dicyandiamide, active hydrogen equivalent of 21 g / eq, “jER Cure DICY15” manufactured by Mitsubishi Chemical Corporation.
[(E) component]
MDU-11: 4,4′-methylenebisphenyldimethylurea, manufactured by A & C Catalysts, Inc. omicure 94: phenyldimethylurea, manufactured by PTI Japan.
[(F) component]
C-301N: Aluminum hydroxide, manufactured by Sumitomo Chemical Co., Ltd.
[Carbon fiber]
Carbon fiber: Pyrofil TR50S15L, manufactured by Mitsubishi Rayon Co., Ltd.

<Examples 1-2 and Comparative Examples 1-2>
Example 1
As shown in Table 1, using Nofia HM1100 as component (A), jER807 and jER828 as component (B), YDPN-638 as component (C), DICY15 as component (D), and MDU-11 as component (E) An epoxy resin composition was prepared.

  First, according to the composition described in Table 1, the mass ratio of the component (B) (liquid), the component (D) (solid) and the component (E) (solid) is 1: 1. Weighed into a container, stirred and mixed. This was further finely mixed with a three roll mill to obtain a curing agent master batch.

  Subsequently, components other than the curing agent master batch in the composition shown in Table 1 were weighed into a flask, heated to 140 ° C. using an oil bath, and dissolved and mixed. Then, it cooled to about 65 degreeC, the said hardening | curing agent masterbatch was added there, and the epoxy resin composition was obtained by stirring and mixing.

  Using the obtained epoxy resin composition, a prepreg and a fiber reinforced composite material were prepared in accordance with <prepreg creation method 1> and <fiber reinforced composite material plate creation method 1> described later. Further, physical properties and flame retardancy were evaluated according to <Evaluation Method> described later. The results are shown in Table 1.

(Example 2)
As shown in Table 1, Nofia HM1100 as component (A), jER828 as component (B), Epon-165 as component (C), DICY15 as component (D), Omicure 94 as component (E), C as component (F) An epoxy resin composition was prepared using -301N.

  First, a curing agent master batch was prepared in the same manner as in Example 1 with the composition shown in Table 1.

  Subsequently, components other than the curing agent master batch and metal hydroxide (F) in the composition shown in Table 1 were weighed into a flask, heated to 140 ° C. using an oil bath, and dissolved and mixed. Thereafter, the metal hydroxide (F) was added and stirred and mixed while cooling to about 65 ° C. The epoxy resin composition was obtained by cooling to about 65 degreeC, adding the said hardening | curing agent masterbatch there, and stirring and mixing.

  Using the obtained epoxy resin composition, a prepreg and a fiber reinforced composite material were prepared in accordance with <prepreg creation method 2> and <fiber reinforced composite material plate creation method 2> described later. Further, physical properties and flame retardancy were evaluated according to <Evaluation Method> described later. The results are shown in Table 1.

(Comparative Example 1)
As shown in Table 1, except for jER828 as component (B) and YDPN-638 as component (C), Nofia HM1100 as component (A), jER807 as component (B), and component (D) Except having changed the content of DICY, the epoxy resin composition was prepared similarly to Example 1, and the physical property and the flame retardance were evaluated. The results are shown in Table 1.

(Comparative Example 2)
As shown in Table 1, except for changing the contents of (B) component jER807 and (D) component DICY, except for (B) component jER828 and (C) component YDPN-638. An epoxy resin composition was prepared in the same manner as in Example 1, and the physical properties and flame retardancy were evaluated. The results are shown in Table 1.

(Comparative Example 3)
As shown in Table 1, an epoxy resin composition was prepared in the same manner as in Example 2 except that the content of C-301N as the component (F) was changed except for the Nofia HM1100 as the component (A). And flame retardancy was evaluated. The results are shown in Table 1.

<Prepreg creation method 1>
The obtained epoxy resin composition was formed into a film using an M-500 comma coater manufactured by Hirano Techseed Co., Ltd., and a resin film having a resin basis weight of 49.3 g / m ² was produced. This resin film was laminated on both sides of a carbon fiber sheet having a fiber basis weight of 230 g / m ² obtained by aligning carbon fibers, impregnated with a heating roll, a fiber basis weight of 230 g / m ² , and a resin content of 30% by mass. Get the prepreg.

<Prepreg creation method 2>
The obtained epoxy resin composition was formed into a film with an M-500 comma coater manufactured by Hirano Techseed Co., Ltd., and a resin film having a resin basis weight of 109.4 g / m ² was produced. This resin film was laminated on both surfaces of a carbon fiber sheet having a fiber basis weight of 290 g / m ² obtained by aligning carbon fibers, impregnated with a heating roll, and a fiber basis weight was 290 g / m ² , and the resin content was 43% by mass. Get the prepreg.

<Fiber-reinforced composite material plate preparation method 1>
The obtained prepregs were cut into 300 mm squares, and 5 sheets were stacked so that the fiber direction would be [0 ° / 90 ° / 0 ° / 90 ° / 0 °], 130 ° C. × 60 minutes, heating rate 2 ° C. / And cured in an autoclave under a pressure of 0.6 MPa to obtain a 1 mm thick fiber-reinforced composite material plate ([0 ° / 90 ° / 0 ° / 90 ° / 0 °]).

<Fiber-reinforced composite material board preparation method 2>
The obtained prepreg was cut into 320 mm squares, and three sheets were stacked so that the fiber direction would be [0 °] _{3. Under} the conditions of 135 ° C. × 60 minutes, temperature increase rate of 1.7 ° C./minute, and pressure of 0.6 MPa. Curing in an autoclave yields a 1 mm thick fiber reinforced composite plate ([0 °] ₃ ).

<Evaluation method>
(1) Measurement of DMA G′-Tg (cured resin):
After placing the uncured epoxy resin composition in the oven, the temperature in the oven is increased at 10 ° C / min, and the resin plate having a thickness of 2 mm is created by holding and curing at 140 ° C for 10 minutes. did. The obtained resin plate was processed into a test piece by length 55 mm × width 12.7 mm. Using the ARES-RDS manufactured by TA Instruments, the test specimen was logarithmically plotted with storage elastic modulus G ′ against temperature at a measurement frequency of 1 Hz and a heating rate of 5 ° C./min. The temperature obtained from the intersection of the approximate straight line and the approximate straight line in the region where G ′ is transferred was recorded as DMA G′-Tg.

The higher the DMA G′-Tg, the better the heat resistance.
(2) Measurement of DMA G′-Tg (fiber reinforced composite material plate):
The 1 mm-thick fiber-reinforced composite material plate obtained in <Fiber-reinforced composite material plate preparation method 1> was processed into a test piece by length 55 mm × width 12.7 mm. Using the ARES-RDS manufactured by TA Instruments, the test specimen was logarithmically plotted with storage elastic modulus G ′ against temperature at a measurement frequency of 1 Hz and a heating rate of 5 ° C./min. The temperature obtained from the intersection of the approximate straight line and the approximate straight line in the region where G ′ is transferred was recorded as DMA G′-Tg.

The higher the DMA G′-Tg, the better the heat resistance.
(3) UL-94V combustion test (resin cured product):
An uncured epoxy resin composition is cured at an oven atmosphere temperature of 140 ° C. × 10 minutes (temperature increase rate is 10 ° C./minute) to form a 2 mm thick resin plate, and then processed to a length of 127 mm × width of 12.7 mm A test piece was obtained. About this test piece, the combustion test was implemented according to UL-94V specification using the combustion tester by Suga Test Instruments. That is, the test piece was vertically attached to the clamp, flame contact with a 20 mm flame was performed for 10 seconds, and the combustion time was measured. A burn test was performed on five specimens, and the number of samples burned to the clamp, the maximum value of each burn time, and the sum of the five burn times (total burn time) were recorded. Moreover, determination [V-0, V-1, V-2, fail] was performed based on the result. As for flame retardancy, V-0 is most excellent, and V-1, V-2 and fail are in that order.
(4) FAR combustion test (fiber reinforced composite material plate):
The fiber reinforced composite material plate ([0 °] ₃ ) obtained in <Fiber reinforced composite material plate preparation method 2> was processed into a test piece by length 150 mm × width 150 mm. A sample is heated with a radiant heat source of 3.5 W / cm ^{2 in} an apparatus through which air of 0.04 m ³ / s passes, and from the detected value, a peak value of up to 5 minutes and an integrated value of 2 minutes Was calculated. Moreover, determination [Pass, Fail] was performed based on the result. As for flame retardancy, Pass indicates that the peak value and the integral value are each 65 or less, and Fail indicates a value higher than that.

  In Table 1, “phosphorus atom content (mass%)” indicates the phosphorus atom content (mass%) in the epoxy resin composition.

  As shown to the said result, the hardened | cured material obtained from the epoxy resin composition of Example 1 containing (C) component was excellent in a flame retardance and heat resistance. Moreover, the fiber reinforced composite material which hardened | cured the prepreg produced using the epoxy resin composition of Example 1 was excellent in the flame retardance and heat resistance similarly to the resin hardened | cured material. Moreover, the fiber reinforced composite material which hardened | cured the prepreg produced using the epoxy resin composition of Example 2 was excellent in a flame retardance, and heat resistance was also favorable.

On the other hand, Comparative Examples 1 and 2 containing no component (C) were excellent in flame retardancy, but the heat resistance of the cured product and the fiber-reinforced composite material was low. The flame retardant property of Comparative Example 3 containing no component (A) was inferior.

Claims (10)

A compound (A) represented by the following formula (a), a bifunctional epoxy resin (B), a trifunctional or higher functional epoxy resin (C), and an epoxy resin curing agent (D), the trifunctional or higher functional epoxy resin ( The epoxy resin composition whose content of C) is 10-95 mass parts with respect to a total of 100 mass parts of the said bifunctional epoxy resin (B) and a trifunctional or more than trifunctional epoxy resin (C).

... (a)
(In the above formula (a), n represents an integer of 2 to 500.)   2. The epoxy resin composition according to claim 1, wherein the content of the compound (A) is such that the phosphorus atom content in the epoxy resin composition is 0.05 to 3.5 mass%.   Furthermore, the epoxy resin composition of Claim 1 or 2 containing a metal hydroxide (F).   The epoxy resin composition according to claim 3, wherein the metal hydroxide (F) is aluminum hydroxide.   A prepreg obtained by impregnating a reinforcing fiber assembly with the epoxy resin composition according to any one of claims 1 to 4.   The prepreg according to claim 5, comprising carbon fibers as the reinforcing fibers constituting the reinforcing fiber assembly.   A fiber-reinforced composite material obtained by curing the prepreg according to claim 5.   The fiber reinforced composite material according to claim 7, wherein the flame retardancy when the thickness is 1 mm is UL-94V and V-0 or V-1.   The fiber reinforced composite material according to claim 7, wherein the flame retardancy when the thickness is 1 mm is FAR 25.853, a-1 Part IV, and Pass.   A structure partly or entirely composed of the fiber-reinforced composite material according to any one of claims 7 to 9.