JPH09278914A - Prepreg and carbon-fiber reinforced plastics - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fiber-reinforced plastic having both excellent mechanical properties and flame retardance and a prepreg excellent in moldability in order to obtain the fiber-reinforced plastics. SOLUTION: This prepreg comprises carbon fibers impregnated with a composition comprising an epoxy resin component composed of at least one epoxy resin selected from the group of brominated epoxy resins, bisphenol A type epoxy resins having a high epoxy equiv., novolak type epoxy resins, bisphenol A type epoxy resins having a low epoxy equiv. and tetraglycidyldiaminodiphenylmethane, a curing agent for the epoxy resin and antimony trioxide. Furthermore, the carbon-fiber reinforced plastics is obtained from the prepreg.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant prepreg and a fiber reinforced plastic. In particular, OA devices such as laptop computers and handy terminals, headphone stereos, AV devices such as CD players and video camcorders, electric and electronic products such as vacuum cleaners and washing machines are made light and thin, and they also have excellent flame retardant properties. The present invention relates to prepreg and carbon fiber reinforced plastic.

[0002]

2. Description of the Related Art Carbon fiber reinforced plastics composed of carbon fibers and a matrix resin are particularly excellent in mechanical properties, so that they can be used for structural applications such as aircraft such as golf clubs, tennis rackets, fishing rods and other sports applications. It has been used for a wide range of applications ranging from fields. Such a carbon fiber reinforced plastic is usually produced by using a prepreg obtained by impregnating carbon fiber with a resin composition.

A prepreg is made of a reinforcing fiber impregnated with a resin and is generally classified into a sheet prepreg (hereinafter referred to as a sheet prepreg) and a strand prepreg (hereinafter referred to as a yarn prepreg).

The sheet prepreg includes continuous fibers arranged in one direction in the plane of the sheet, a continuous fiber woven fabric, discontinuous fibers arranged in any direction, depending on the purpose. There are various forms of reinforcement.

In recent years, office automation equipment such as notebook computers and handy terminals, headphone stereos, and C
It has been proposed to use carbon fiber reinforced plastics to reduce the weight and thickness of electric and electronic products such as AV equipment such as D players and video camcorders. Carbon fiber reinforced plastics have been proposed for these electric and electronic products. Incorporation requires flame retardancy for disaster prevention.

On the other hand, the yarn prepreg is formed by impregnating a continuous fiber bundle in which carbon fiber filaments are arranged in one direction with a resin. The demand for this yarn prepreg as a tension material for bridge cables and prestressed concrete, and as a member for filament winding has increased rapidly in recent years. However, when incorporating a fiber-reinforced composite material into such a structural member, flame retardation for disaster prevention is an essential element.

As a method of making an epoxy resin flame-retardant,
(1) Method using halogenated epoxy resin (Japanese Patent Publication Sho 59
No. 52653), (2) a method using a halogen-containing curing agent, (3) a method using an addition type flame retardant such as a phosphorus compound, a halogen compound, an antimony compound, etc. (1) and (2) are methods of incorporating a halogen atom directly into the network structure of the epoxy resin by using a reactive flame retardant, and it is possible to make the flame retardant without significantly lowering the physical properties of the epoxy resin. . The method (3) is characterized in that flame retardation can be easily achieved, and a combination of flame retardants can be relatively easily performed.

Although conventional epoxy resin flame-retardant technology has the above-mentioned characteristics, the moldability of the sheet prepreg is insufficient. For example, if the adhesiveness of the sheet prepreg is insufficient, the sheet prepregs will not adhere to each other during the lamination of the sheet prepregs, making it difficult to accurately align the directions of the reinforcing fibers. On the other hand, if the tackiness is excessive, the laminated sheet prepreg cannot be peeled off, which makes it difficult to correct the reinforcing fibers in the correct direction.

Further, if the flow control of the sheet prepreg is not proper, the resin flow becomes too large at the time of molding, and the resin content of the molded product becomes small. On the contrary, when the resin flow is small, voids occur in the molded product. Then, in any case, the problem that the mechanical properties of the molded product deteriorated was pointed out.

Also in the case of the yarn prepreg, the handling property and the moldability were insufficient. For example, the yarn prepreg is wound around a bobbin without interposing a release paper or the like, and therefore, when the tackiness is excessive, problems such as yarn breakage are likely to occur during unwinding. On the contrary, if a large amount of solid epoxy resin or thermoplastic resin is used to reduce the tackiness,
The yarn prepreg lacks flexibility and makes bobbin winding difficult. Furthermore, if the flow control of the yarn prepreg is not appropriate, the resin flow during molding will become too large and the resin content of the molded product will decrease, and it will be difficult to manufacture ropes by combining multiple yarn prepregs. Defects such as the lack of flexibility due to the adhesion of the wires to each other occur. On the other hand, when the resin flow is small, there are problems such as voids in the molded product and resin defects on the roll surface. In either case, it has been pointed out that there is a problem that the mechanical properties and handleability of the molded product deteriorate.

For the purpose of solving the drawbacks of these yarn prepregs, for example, Japanese Patent Publication Nos. 60-37810 and 61-25.
Nos. 740 and 62-5447 disclose an epoxy resin having a specific molecular weight and a method of combining it with a thermoplastic resin and the like, but the flame retardancy of a prepreg is not described.

On the other hand, Japanese Patent Publication Nos. 59-2446 and 59-5.
2653, 62-44770 and 63-3805.
No. 0 discloses a carbon fiber reinforced prepreg and a composite material using a flame-retardant epoxy resin composition containing a brominated epoxy resin. However, in addition to insufficient flow control when molding the yarn prepreg, these resin compositions have a flame retardance level sufficient for use in aircraft and building materials (for example, V-0 level in UL test). ) Was not reached.

[0013]

DISCLOSURE OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a fiber reinforced plastic having both excellent mechanical properties and flame retardancy, and a prepreg excellent in moldability for obtaining the same. To provide.

[0014]

In order to solve the above problems, the prepreg of the present invention has the following constitution. That is, brominated epoxy resin, epoxy equivalent is 400-5,
At least one selected from the group consisting of 500 bisphenol A type epoxy resins, novolac type epoxy resins, bisphenol A type epoxy resins having an epoxy equivalent of 250 or less, and N, N, N ', N'-tetraglycidyldiaminodiphenylmethane. Is a prepreg obtained by impregnating carbon fiber with an epoxy resin component composed of the epoxy resin, a curing agent for an epoxy resin, and a composition composed of antimony trioxide.

In order to solve the above problems, the carbon fiber reinforced plastic of the present invention has the following constitution. That is, it is a carbon fiber reinforced plastic obtained from the prepreg.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The brominated epoxy resin used in the present invention is a glycidyl ether type epoxy resin of brominated bisphenol A and a glycidyl ether type epoxy resin of brominated phenol novolac resin. These have a bromine content of 16 to 50% by weight,
Epiclon (Epc) 152, Epiclon (Epc) 1
It is commercially available under the trade names of 120, EBS340, Ep1050, BRENS and the like. A cured product obtained from this resin has high water resistance and elastic modulus, but has a large epoxy equivalent and thus has a low crosslink density and low heat resistance. Furthermore, the resin elongation is low due to steric hindrance due to the bromine atom. Considering these characteristics, the addition amount of brominated epoxy resin is
10 to 60% by weight in epoxy resin, preferably 20 to 4
The content is preferably 0% by weight. If it is more than this range, the heat resistance and water resistance of the cured product may be lowered, or the adhesiveness of the prepreg may be too small. On the other hand, if the addition amount is reduced, the flame retardancy, elastic modulus and water resistance of the cured product may decrease. When the elastic modulus of the resin decreases, the interlayer shear strength and compressive strength of the obtained carbon fiber reinforced plastic (hereinafter abbreviated as CFRP) decrease.

In the present invention, the bisphenol A type epoxy resin means a bisphenol A diglycidyl ether type epoxy resin. Epoxy equivalent is 400 to 5.5
As a bisphenol A type epoxy resin of 00, Ep
1001, Ep1004, Ep1009, Epiclon (Epc) 4050, Epiclon (Epc) 9055,
It is marketed under the trade name of DER668, DER669 and the like. The purpose of adding such a high molecular weight epoxy resin is to control the tackiness of the prepreg and the resin flow during molding. For this purpose, an elastomer such as nitrile rubber or a thermoplastic resin may be added. However, when nitrile rubber is added, the flame retardancy, heat resistance, and elastic modulus of the resin are often greatly impaired, and when a thermoplastic resin is used, a prepreg prepared by a wet method using a low boiling point solvent such as methyl ethyl ketone is used. There is a disadvantage that it cannot be realized. Therefore, the epoxy equivalent is 400 to
The method of using a high molecular weight bisphenol A type epoxy resin of 5,500 is advantageous. However, a cured product obtained by using this resin in a large amount has a large resin elongation, but has a low elastic modulus and Tg. Further, since it is solid at room temperature, the tackiness of the prepreg becomes low. Furthermore, the high melt viscosity reduces the resin flow during molding. Therefore, considering these characteristics, the addition amount of this resin is 5 to 40% by weight, preferably 10 to 30% by weight in the epoxy resin component. If it exceeds this range, the elastic modulus and T of the cured product
In some cases, g may decrease, or the adhesiveness of the prepreg or the resin flow during molding may become too small. On the other hand, if the addition amount is reduced, the elongation of the cured product may decrease, the tackiness of the prepreg and the flow during molding may become too large.

In the resin composition of the present invention, in addition to the above epoxy resin, a novolac type epoxy resin, a bisphenol A type epoxy resin having an epoxy equivalent of 250 or less, preferably 150 to 250, or N, N, N '. ,
N'-tetraglycidyl diaminodiphenylmethane is used.

The bisphenol A type epoxy resin having an epoxy equivalent of 250 or less is Ep828, YD128, Epiclon (Epc) 840, ELA128, DER331.
Etc. are commercially available. The cured product obtained from this resin has a high resin elongation but a low elastic modulus. Further, since it is liquid at room temperature, the adhesiveness of the prepreg becomes high. Furthermore,
Since the melt viscosity is low, the resin flow during molding becomes large. Therefore, considering these characteristics, when using a bisphenol A type epoxy resin having an epoxy equivalent of 250 or less, the addition amount is 10 to 5 in the epoxy resin component.
It is good to set it to 0% by weight, preferably 10 to 40% by weight. If the amount is more than this range, the elastic modulus of the cured product may decrease, and the tackiness of the prepreg and the resin flow during molding may become too large. On the other hand, if the addition amount is reduced,
The elongation of the cured product may decrease, the tackiness of the prepreg and the resin flow during molding may become too small.

Phenol novolac type epoxy resin and cresol novolac type epoxy resin which are novolac type epoxy resins are glycidyl ether type epoxy resins of phenol novolac resin and cresol novolac resin, and are Ep152, Ep154, DER485, N7.
40, N673, ESCN220, etc. are marketed. These novolac type epoxy resins have high heat resistance,
Although it has an advantage of being a cured product having high water resistance, it has a drawback that it is a cured product having a low elastic modulus. In consideration of these characteristics, when the novolac type epoxy resin is used, the addition amount is preferably 10 to 60% by weight in the epoxy resin component. If it exceeds this range, the elastic modulus of the cured product will decrease,
If it is too small, the water resistance and the elongation of the cured product may decrease. Further, in the case of a liquid phenol novolac resin, if it exceeds the above range, the adhesiveness of the prepreg may become too large. On the other hand, if the amount added is too small, the tackiness of the prepreg may become too small. On the other hand, in the case of a solid cresol novolac resin, if the amount is more than the above range, the tackiness of the prepreg may be too small, and if the addition amount is too small, the tackiness of the prepreg may be too high.

In the present invention, when N, N, N ', N'-tetraglycidyldiaminodiphenylmethane is used, its addition amount is 10 to 60% by weight, preferably 10 to 50% by weight in the epoxy resin component. Good to do. If it is more than this range, the elongation and water resistance may decrease, and if it is less than this range, the heat resistance and elastic modulus of the cured product may decrease.

Examples of the curing agent for epoxy resin used in the present invention include dicyandiamide (hereinafter abbreviated as DICY), diaminodiphenyl sulfone (hereinafter abbreviated as DDS), aminobenzoic acid esters, various acid anhydrides and the like. . DICY is preferably used because it has excellent storage stability for the prepreg. Further, when an aromatic diamine such as DDS is used as a curing agent, an epoxy resin cured product having good heat resistance can be obtained. Further, a urea compound, an amine salt of boron trifluoride, an imidazole compound, or the like can be used in combination with these curing agents or alone. When DICY is used as the curing agent,
It is common to use a curing accelerator such as 3,4-dichlorophenyl-1,1-dimethylurea (hereinafter abbreviated as DCMU) together.

In the present invention, the amount of antimony trioxide added is such that the composition 10 comprising the epoxy resin component and the curing agent is added.
0.5 to 5 parts by weight, preferably 0.5 to 0 parts by weight
It is recommended to set it to 3.5 parts by weight. If it is more than this range, the elongation of the cured product may decrease, and if it is less, the flame retardancy may decrease. Further, antimony trioxide is usually in the form of particles, and the particle size thereof is 0.1 to 5 μm, preferably 0.2 to 3 μm. If the particle size exceeds 5 μm, the flame retardancy may decrease, and it is usually difficult to obtain a particle size less than 0.1 μm. In the present invention, since the above-mentioned brominated epoxy resin is used in combination with antimony trioxide, CFRP obtained by the synergistic effect thereof is obtained.
Has excellent flame retardancy far beyond what is expected, and since it uses at least three kinds of epoxy resins described above in combination, it is excellent in handleability and moldability when used as a prepreg. In particular, when used as a yarn prepreg, the degree of tackiness and the flow control are appropriate, which is useful.

The cured product of the epoxy resin composition used in the present invention preferably has a tensile elongation of 5% or more. Accordingly, in the case of the yarn prepreg, when the fiber reinforced composite material is used, a sufficiently high carbon fiber strength development rate can be obtained.

The tensile elongation of the cured product of the epoxy resin composition is measured as follows. From a 2 mm thick cured plate to J
According to the method described in IS-K-7113, a dumbbell type test piece processing machine is used to form a test piece, a strain gauge is attached to the test piece, and a tensile test is performed at a pulling speed of 1 mm / min. The curing conditions of the resin composition for obtaining a cured product are, in the case of a resin composition in which a DICY curing agent is used in combination with a curing auxiliary, a resin in which DDS is used as a curing agent at 130 ° C. for 2 hours. In the case of a composition, the above-mentioned epoxy resin composition, which is kept at 180 ° C. for 2 hours, is impregnated into carbon fiber as a reinforcing material to form a prepreg.

The carbon fiber used in the present invention is preferably a polyacrylonitrile-based carbon fiber in consideration of mechanical properties.

The form of the carbon fiber can be selected from unidirectional or woven or non-woven fabric, knitted fabric or braid. Further, glass fibers, aramid fibers or metal fibers may be used in combination.

Particularly in the yarn prepreg, the number of filaments of the carbon fiber yarn to be used is 3,000 to 100,
000, preferably in the range of 6,000 to 50,000. A carbon fiber yarn having a small number of filaments is generally expensive, which leads to an increase in the cost of the obtained prepreg. Further, the workability may be deteriorated in the case of thick yarn carbon fiber having too many filaments.

In the case of a yarn prepreg, when a continuous carbon fiber yarn having substantially no twist is used, the strength expression rate of the carbon fiber in the composite material is high, and in particular, an application requiring tensile strength, for example, a fiber reinforced composite material. Suitable for stranded wires and the like. When the carbon fiber yarn has twists, the filaments constituting the fiber bundle are not arranged in parallel, which may cause a decrease in strength of the prepreg itself and the composite material produced using the prepreg.

As a continuous carbon fiber yarn having substantially no twist, quantitatively, the hook drop value is 10 cm or more, and further,
Carbon fibers of 12 cm or more are preferred. Here, the hook-drop value is a value represented by the distance that the carbon fiber bundle is vertically hung down in an atmosphere of a temperature of 23 ° C. and a humidity of 60%, a weight of 12 g is hooked on the carbon fiber bundle, and the weight falls after 30 minutes. This value decreases with twist.

Carbon fibers having a tensile elastic modulus of 200 GPa or more and a breaking strain energy of 38,000 kJ / m ³ or more also have a high carbon fiber expression rate in the composite material obtained from the yarn prepreg, and particularly have a high tensile strength. Suitable for required applications. Here, the tensile elastic modulus is a value E measured according to JIS R7601, and the fracture strain energy is the tensile strength σ measured according to JIS R7601 and the above E value, It means W calculated based on the formula W = σ ² / 2E.

When a fiber reinforced composite material is manufactured from a yarn prepreg using a carbon fiber having a tensile elastic modulus of less than 200 GPa, it is necessary to increase the cross-sectional area in order to suppress the deformation amount of the composite material within the design allowable range. As a result, the weight reduction effect is reduced and the use may be limited. For example, when the fiber-reinforced composite material according to the present invention is applied as a bridge cable or prestressed concrete tendons,
It becomes difficult to keep the amount of deformation in the applied tensile stress field within a predetermined range.

The breaking strain energy of carbon fiber is 38,0.
When it is less than 00 kJ / m ^3, it is not possible to obtain a sufficiently high carbon fiber strength development rate in a composite material, particularly a tensile member such as a bridge cable or a prestressed concrete tension material.

Further, the diameter of the carbon fiber used in the present invention is 3 to 1
It is preferably 0 μ. When the diameter of the carbon fiber is less than 3 μ, when the yarn prepreg is formed, the fiber diameter is too small and fluff is likely to be generated, so that there is a problem in handleability and resin impregnation property of the fiber in the epoxy resin impregnation step. On the other hand, 10
If it exceeds μ, the fiber bundle may be too rigid, and a problem may occur in the process passability of the fiber at the guide portion or the like in the epoxy resin impregnation step.

The yarn prepreg preferably has an appropriate resin / fiber adhesive force. This adhesive strength has an interlaminar shear strength of 65, which is one of the characteristics of composite materials obtained by curing prepreg.
˜140 MPa, more preferably 75 to 120 MPa. When the interlaminar shear strength is less than 50 MPa, the durability when used as a tensile structural member decreases. On the other hand, when it exceeds 140 MPa, the utilization factor of tensile strength decreases. These interlaminar shear strengths are achieved by adjusting the surface treatment of the carbon fiber, the elastic modulus of the resin, and the interfacial adhesion.

The production method used to obtain the prepreg of the present invention is a so-called wet method in which the resin composition is dissolved in a solvent in advance to reduce the viscosity and the resin composition is impregnated while being immersed in a reinforcing material such as continuous carbon fiber yarn. Or, the viscosity of the resin composition is reduced by heating, a film is formed by coating on a roll or release paper, and a reinforcing material such as continuous carbon fiber yarn is pressed and impregnated into the film, so-called hot melt method Either may be adopted.

Such a prepreg is made into a carbon fiber reinforced plastic by heating and curing the resin composition.

[0038]

The present invention will be described in more detail with reference to the following examples. In addition, in this example, the flame-retardant property of the CFRP plate (94
The UL combustion test) was measured as follows.

(1) A CFRP plate having a thickness of 0.8 and a length of 1
A test piece is prepared by cutting it to 27 mm and a width of 12.7 mm.

(2) In a 19 mm high blue burner flame without yellow chips, the test piece was held for 10 seconds so that its tip was at a position 9.5 mm from the tip of the flame, and then removed. , Measure the time from removal to the end of combustion (combustion time).

(3) After the combustion is completed, the same operation as (2) is repeated and the combustion time is measured.

(4) Five test pieces (2), (3)
When the burning time of 10 pieces is 10 seconds or less and the total burning time of 10 pieces is 50 seconds or less, the V-0 standard is satisfied.

The material components of the resin composition used in the examples are shown in Table 1.

[0044]

[Table 1] [Example 1] 20 parts by weight of Ep1009, 35 parts by weight of Ep154, 25 parts by weight of Ep828, 20 parts by weight of Ep
pc152, 2.5 parts by weight of antimony trioxide, 3.5
Parts by weight DICY, and 4.0 parts by weight DCMU
Was dissolved in a mixed solvent of methyl ethyl ketone and methanol, and a solution having a solid content of 50% was added to a carbon fiber woven fabric CO manufactured by Toray Co., Ltd.
A sheet prepreg having a resin content of 40% was manufactured by impregnating 6343B (fiber basis weight: 198 g / m ² ) and then drying. The minimum viscosity of the resin solid content measured by the temperature rising method (1.5 ° C./min) was 30 poise.

The obtained sheet prepreg had good tackiness. The sheet prepreg was cured in an autoclave at 130 ° C. for 2 hours under the condition of 6 Kgf / cm ² to obtain a CFRP plate. The obtained CFRP plate (0.
When a flame retardancy test was performed on the
The average value of the burning time of 10 times performed for one set of samples was 2 seconds, which showed excellent flame retardancy of V-0 class.
The bending strength and the interlaminar shear strength were 80 and 7.5 Kgf / mm ² , respectively.

[Comparative Example 1] Brominated epoxy resin Epc1
52 is phenol novolac type epoxy resin Ep154
A sheet prepreg and a CFRP plate were produced in the same manner as in Example 1 except that the above was changed to. CFRP plate (0.8
When the flame retardancy of (mm thickness) was evaluated, the average value of the burning time was 10 seconds or more, and the flame retardancy was inferior.

[Comparative Example 2] Liquid bisphenol A without using solid bisphenol A type epoxy resin Ep1009
The resin content ratio was 40 in the same manner as in Example 1 except that the addition amount of the epoxy resin Ep828 was changed to 45% by weight.
% Sheet prepreg and CFRP plate were obtained. The minimum viscosity of the resin solid content measured by the temperature rising method (1.5 ° C / min) is 0.
It was 1 poise. The CFRP plate obtained had a large resin flow, and thus the resin content rate was reduced to 32%. The bending strength and the interlaminar shear strength of this CFRP plate were 62 and 5.1 Kgf / mm ² , respectively, and the mechanical properties were extremely poor.

[Comparative Example 3] A sheet prepreg and a CFRP plate were obtained in the same manner as in Example 1 except that antimony trioxide was not used. The CFRP plate obtained (0.8
When the flame retardancy of (mm thickness) was evaluated, the average value of the burning time was 10 seconds or more, and the flame retardancy was inferior.

Example 2 Brominated Epoxy Resin Epc1
52 and liquid bisphenol A type epoxy resin Ep8
A sheet prepreg and a CFRP plate were obtained in the same manner as in Example 1 except that the addition amounts of 28 were changed to 70 parts by weight and 30 parts by weight, respectively. Although the obtained sheet prepreg had insufficient tackiness as compared with Example 1, the mechanical properties of the CFRP plate were equivalent to those of Example 1.

Example 3 Brominated Epoxy Resin Epc1
52, phenol novolac type epoxy resin Ep15
4 and liquid bisphenol A type epoxy resin Ep8
A sheet prepreg and a CFRP plate were produced in the same manner as in Example 1 except that the addition amount of 28 was changed to 5 parts by weight, 45 parts by weight and 30 parts by weight. When a flame retardancy test was conducted, the average value of the burning time was 4 seconds, which was inferior to that of Example 1, but showed flame retardancy satisfying the V-0 standard.

[Example 4] Solid bisphenol A type epoxy Ep1009 and liquid bisphenol A type epoxy Ep828 were added in amounts of 50 parts by weight and 30 parts by weight, respectively.
A sheet prepreg and CFRP having a resin content ratio of 40% by weight in the same manner as in Example 1 except that the amount was changed to parts by weight.
I got a board. The minimum viscosity of the resin solid content measured by the temperature rising method (1.5 ° C./min) was 150 poise. The obtained CFR
Although voids that were considered to be derived from the small resin flow were observed in the P plate, the bending strength and the interlaminar shear strength were 78 and 7.1 Kgf / mm ² , respectively, which was almost the same as in Example 1.

[Example 5] Resin containing was carried out in the same manner as in Example 1 except that the addition amounts of the solid bisphenol A type epoxy resin Ep1009 and the liquid bisphenol A type epoxy resin Ep828 were changed to 3 parts by weight and 42 parts by weight, respectively. 40% by weight of sheet prepreg and C
An FRP plate was obtained. The minimum viscosity of the resin solid content measured by the temperature rising method (1.5 ° C./min) was 5 poise. CF obtained
The resin content of the RP plate is 38 because the resin flow is large.
%, But the flexural strength and interlaminar shear strength were 79 and 7.3 Kgf / mm ² , respectively.
Was almost the same.

Example 6 A sheet prepreg and a CFRP plate were obtained in the same manner as in Example 1 except that the addition amount of antimony trioxide was changed to 7 parts by weight. The obtained CFR
The bending strength and the interlaminar shear strength of the P plate were 75 and 6.9 Kgf / mm ² , respectively, which were slightly inferior to those of Example 1.

Example 7 A sheet prepreg and a CFRP plate were obtained in the same manner as in Example 1 except that the amount of antimony trioxide added was changed to 0.3 part by weight. Obtained C
Regarding the flame retardancy of the FRP plate, the average value of the burning time was 4.5 seconds, which was inferior to that of Example 1, but showed the flame retardancy satisfying the V-0 standard.

Example 8 The components shown in Table 2 were uniformly kneaded using a kneader to prepare a resin composition. The tensile elongation at break of the cured product obtained by heating this composition at 130 ° C. for 2 hours was 6.3%.

Next, carbon fiber "Torayca" manufactured by Toray Industries, Inc.
(Registered trademark) T700SC-24K-50C (Number of filaments: 24,000
Book, E = 230GPa, σ = 4,900MPa, practically untwisted) was opened with a widening bar, and then the resin had a weight fraction Wr of 29% (Wf = 71
%) Was impregnated with hot melt to obtain a yarn prepreg.

The obtained yarn prepreg was aligned in parallel to prepare a sheet. Ply this on a flat tool, cover it with a bag film, depressurize the inside, and then cure it in an autoclave under the conditions of 100 ° C for 1 hour + 130 ° C for 1 hour to remove CFRP plate (Vf = 64% ) Was produced.
When a flame retardancy test was performed on the obtained CFRP plate (0.8 mm thickness), the average value of the burning time of 10 times performed for one set of 5 samples was 2 seconds, which was excellent flame retardancy of V-0 class. Showed sex.

A 25 cm long test piece was cut out from this CFRP plate and subjected to a tensile test based on ASTM D3039-76. The tensile strength was 3.0 GPa and the strength development rate was 96%. A 1 cm-long test piece was cut out and subjected to an interlaminar shear test based on ASTM D2344. As a result, the interlaminar shear strength was 105 MPa.

The term “strength development rate” as used herein means the actual value of tensile strength of composite material / (carbon fiber tensile strength × fiber volume content), and the carbon fiber tensile strength is obtained based on JIS R7601. It is the assigned value.

The 20 yarn prepregs thus obtained were bundled so that the reinforcing fibers were arranged in parallel to the axial direction while fixing the bundled position of the yarn in the cross section, and the outer periphery was covered with a polyester fiber knitted fabric. After that, it was cured in a curing oven at 130 ° C. for 2 hours to obtain a wire. The volume fraction Vf of carbon fiber in the obtained strand was 63% by volume. This wire is 800m long
Cut into m, wrap a glass fiber woven fabric with a width of 200 mm impregnated with epoxy resin on both ends and harden it, then attach it to Shimadzu's autograph (maximum load 98 kN), strain rate
A tensile test was performed at 2 mm / min. At this time, the tensile strength of the strand was 3.1 GPa and the strength development rate was 95%. Table 2 shows the experimental results.

[Example 9] A yarn prepreg was obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 2. Then, a CFRP plate and an element wire were obtained in the same manner as in Example 8 except that the curing condition was changed to 180 ° C. for 2 hours. The physical properties of the obtained CFRP plate are shown in Example 1.
Was equivalent to Table 2 shows the experimental results.

Example 10 A yarn prepreg, a CFRP plate and a strand were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 2. The elongation of the cured product of the resin composition and the drapability of the prepreg were lower than those of Example 8. In addition, since the resin flow was large, the resin exudation of the obtained strand was slightly larger than that in Example 8. However, the mechanical properties of the CFRP plate and the wire were the same as in Example 8. Table 2 shows the experimental results.

Example 11 A yarn prepreg, a CFRP plate and a strand were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 2. When a flame retardancy test was conducted, the average value of the burning time was 4 seconds, which was inferior to that of Example 8, but showed flame retardancy satisfying the V-0 standard. Table 2 shows the experimental results.

[0064]

[Table 2] [Example 12] A yarn prepreg, a CFRP plate and an element wire were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 3. The CFRP plate had voids that were thought to be due to the small resin flow, but its mechanical properties were almost the same as in Example 8. In addition, the resulting strand had a small resin flow due to a small resin flow, and the resin was deficient on a part of the surface, but the mechanical characteristics were the same as in Example 8. Table 3 shows the experimental results.

[Example 13] A yarn prepreg, a CFRP plate and a strand were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 3. The mechanical properties of the obtained CFRP plate were the same as in Example 8. Table 3 shows the experimental results.

Example 14 A yarn prepreg and strand were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 3. When a flame retardancy test was conducted, the average value of the burning time was 4.0 seconds, which was inferior to that of Example 8, but showed flame retardancy satisfying the V-0 standard. Table 3 shows the experimental results.

[Example 15] A yarn prepreg, a CFRP plate and an element wire were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 3. When the mechanical properties of the manufactured CFRP plate were measured, it was slightly inferior to that of Example 8. Table 3 shows the experimental results.

[0068]

[Table 3] Example 16 The carbon fiber used was changed to carbon fiber “Torayca” (registered trademark) T300B-6K-40B (filament number: 6,000, E = 230 GPa, σ = 3,530 MPa, untwisted yarn) manufactured by Toray Industries, Inc. A yarn prepreg, C
An FRP plate and a wire were prepared. The obtained CFRP plate had the same flame retardance and tensile strength development ratio as in Example 8. The resin exudation and strength development rate of the obtained strands were also the same as in Example 8. Table 4 shows the experimental results.

Comparative Example 4 A yarn prepreg, a CFRP plate and a strand were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 4. When the flame retardancy of the obtained CFRP plate (0.8 mm thickness) was evaluated, the average value of the burning time was 10 seconds or more, and the flame retardancy was poor. Table 4 shows the experimental results.

[Comparative Example 5] A yarn prepreg, a CFRP plate and a strand having a resin content of 30% by weight were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 4. . Since the obtained CFRP plate had a large resin flow, Vf rose to 69%. This CFR
The tensile strength and interlaminar shear strength of P plate are 2.
It was 5 GPa and 80 MPa, and it was found that the mechanical properties were extremely inferior. Further, the resin exudation of the obtained wire becomes excessive, and Vf is 70 as in the CFRP plate.
It became as large as%. Along with this, the tensile strength and the expression rate greatly decreased. Table 4 shows the experimental results.

Comparative Example 6 A yarn prepreg, a CFRP plate and a strand were obtained in the same manner as in Example 8 except that the resin composition used was changed to that shown in Table 4. Obtained C
When the flame retardancy of the FRP plate (0.8 mm thickness) was evaluated, the average value of the burning time was 10 seconds or more, and the flame retardancy was poor. Table 4 shows the experimental results.

[0072]

[Table 4]

[0073]

Industrial Applicability According to the present invention, a fiber reinforced plastic having both excellent mechanical properties and flame retardancy can be obtained, and a prepreg excellent in moldability for obtaining the same can be provided.

Claims (10)

[Claims] 1. A brominated epoxy resin having an epoxy equivalent of 40.
0-5,500 bisphenol A type epoxy resin, and novolac type epoxy resin, epoxy equivalent is 250
The following bisphenol A type epoxy resin, N, N, N ',
A prepreg obtained by impregnating carbon fiber with an epoxy resin component composed of at least one epoxy resin selected from the group consisting of N'-tetraglycidyldiaminodiphenylmethane, a curing agent for epoxy resin, and a resin composition composed of antimony trioxide. . 2. The prepreg according to claim 1, wherein the content of the brominated epoxy resin is in the range of 10 to 60% by weight based on the total weight of the epoxy resin components. 3. The content of the bisphenol A type epoxy resin having an epoxy equivalent of 400 to 5,500 is in the range of 5 to 40% by weight based on the total amount of the epoxy resin components. The prepreg described in 2. 4. The content of antimony trioxide is 0.5 based on 100 parts by weight of the total amount of the epoxy resin component and the curing agent.
The prepreg according to claim 1, wherein the prepreg is 5 to 5 parts by weight. 5. The prepreg according to any one of claims 1 to 4, wherein the prepreg is a yarn prepreg. 6. The prepreg according to claim 5, wherein the carbon fiber is a continuous yarn having substantially no twist. 7. The prepreg according to claim 5, wherein the carbon fiber has a tensile elastic modulus of 200 GPa or more and a breaking strain energy of 38,000 kJ / m ³ or more. 8. A curing agent for an epoxy resin is dicyandiamide, and the resin composition further contains a curing accelerator for the curing agent, and the cured product of the resin composition has a tensile elongation at break of 5%.
It is above, The prepreg according to any one of claims 5 to 7. 9. The prepreg according to claim 5, wherein the epoxy resin curing agent is diaminodiphenyl sulfone, and the cured product of the resin composition has a tensile elongation at break of 5% or more. . 10. A carbon fiber reinforced plastic obtained from the prepreg according to claim 1.