JPS6236421A - Epoxy resin composition for prepreg - Google Patents

Abstract

PURPOSE:To obtain the titled resin composition excellent in toughness, heat resistance, water resistance and tack draping, by mixing a tetrafunctional epoxy resin with specified two epoxy resins, a curing agent and a polyether sulfone. CONSTITUTION:An epoxy resin composition prepared by mixing N,N,N',N'- tetraglycidyldiaminodiphenylmethane, which is commercially available, with N,N,O-triglycidyl-m-aminophenol, a bisphenol epoxy resin, diamino-diphenyl sulfone and polyether sulfone of the formula. Since this epoxy resin is a tetrafunctional epoxy resin, it is advantageous in that a cured product having an increased crosslinking density, high elasticity and high heat resistance can be obtained. The N,N,O-triglycidyl-m-aminophenol is commercially available and this epoxy resin can bring about accelerated curing and improved modulus of a cured product.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an epoxy resin composition for prepreg that has excellent toughness, heat resistance, water resistance, and tuck/drape properties.

[Prior Art] Composite materials made of reinforcing materials such as carbon fibers, glass fibers, and aromatic polyamide fibers and epoxy resins are used for premium sports applications such as golf shafts and fishing rods, taking advantage of their high specific strength and specific modulus. Widely used for structural materials such as aircraft. However, the epoxy resins used in these composite materials have insufficient performance for applications that require greater strength, toughness, heat resistance, and water resistance.

Epoxy resins currently used in aircraft composite materials have N, N, N=, N--tetraglycidyldiaminodiphenylmethane as a main component, and diaminodiphenylsulfone is used as a curing agent. Although this resin composition has high heat resistance, the resin composition has low resin elongation and becomes a brittle cured product. CFRP obtained from this resin composition exhibits excellent heat resistance but low toughness.

Many techniques have been proposed for improving the toughness of epoxy resins. One method is to add a rubber such as acrylonitrile-butadiene copolymer to an epoxy resin, and then cure the epoxy resin to form a rubber phase as a separate phase to prevent cracks and improve adhesive strength. (For example, Japanese Patent Laid-Open No. 57-21
450). Other methods include adding and mixing thermoplastic resins such as polyether sulfone, polysulfone, and polyarylate to epoxy resin to suppress the propagation of cracks in the cured resin, and using this resin to create carbon fiber reinforced composite materials. There are ways to improve toughness (for example, Ding HE
BRITISHPOLYMERJOIJRNAL, Vo
l.

15,) IARcH, 1983, P, 71.28th
5AHPE 5YHPO3IIJH, 1983, P, 3
67, Japanese Patent Publication No. 58-134126). However, although the latter method does not impair the heat resistance and water resistance of the composite material, it is necessary to increase the amount of thermoplastic resin blended to a greater extent in order to provide high toughness.

When the amount of blended thermoplastic resin is increased, the viscosity of the epoxy resin becomes extremely high, which tends to cause poor impregnation with reinforcing materials and poor curing during the prepreg manufacturing or molding process, and impairs the tack and drape properties of the prepreg. Problems arise, such as making lamination work and molding of complex shapes impossible.

[Problems to be Solved by the Invention] An object of the present invention is to provide a resin composition having an appropriate viscosity in the manufacturing process of the resin composition and the manufacturing/molding process of the prepreg for composite materials.
Another object of the present invention is to provide an epoxy resin composition for prepregs that provides prepregs with appropriate tack and drape properties and has excellent toughness, heat resistance, and water resistance.

[Means for Solving the Problems] The present invention provides the following essential components: [A] N,N,N",N"-tetraglycidyldiaminodiphenylmethane [B] N,N,O-triglycidylmethaminophenol [ C] Bisphenol F type epoxy resin [D] This invention relates to an epoxy resin composition for prepregs containing a polyether sulfone represented by diaminodiphenylsulfone.

N,N,N-,N''-tetraglycidyldiaminodiphenylmethane used in the present invention is E[M434 (manufactured by Sumitomo Chemical Co., Ltd.), MY720 (Ciba Geigy Co., Ltd. i1
>, YH434 (manufactured by Tobu Kasei Co., Ltd.) and other trade names. Since this epoxy resin is a tetrafunctional epoxy resin, it has the advantage that it has a high crosslinking density, and a cured product with high elastic modulus and high heat resistance can be obtained. However, it has the disadvantage that the cured product has low elongation and is brittle. Considering these characteristics, the amount of N, N, N=, N--tetraglycidyldiaminodiphenylmethane added is 40 to 40% in the epoxy resin component.
60% by weight is preferred. If the amount exceeds this range, the resulting cured product will become brittle and have poor water resistance. If the amount is decreased, the heat resistance and elastic modulus of the cured product will decrease. Therefore, in these cases, the toughness, heat resistance, and water resistance of CFRP decrease.

The N,N,O-triglycidyl meta-aminophenol used in the present invention is ELM120 (manufactured by Sumitomo Chemical Co., Ltd.)
, YDM120 (manufactured by Tobu Kasei Co., Ltd.). This epoxy resin accelerates curing and improves the elastic modulus of the cured product. However, since the addition of this resin lowers the water resistance of the cured product, the amount added is preferably 10 to 30% by weight based on the epoxy resin component.

The bisphenol F type epoxy resin used in the present invention is commercially available under trade names such as Epiclon 830 (manufactured by Dainippon Ink and Chemicals) and Epicort 807 (manufactured by Yuka Shell Epoxy Co., Ltd.). Addition of this epoxy resin is very preferable because it lowers the viscosity of the epoxy resin composition for prepreg of the present invention and improves tack drapability.

In addition, a compound having an appropriate viscosity can be obtained in the prepreg manufacturing and molding process, and workability can be greatly improved. However, although the cured product obtained from this epoxy resin has high resin elongation, it has slightly low heat resistance. Considering these characteristics, the amount of bisphenol F type epoxy resin added is preferably 20 to 50% by weight in the epoxy resin component.

In addition, epoxy resins other than the epoxy resin used in the present invention include bisphenol A epoxy resin, bisphenol S epoxy resin, phenol novolac epoxy resin, Talesol novolak epoxy resin,
Examples include reaction diluents typified by glycidyl derivatives of glycerin, alicyclic epoxy resins, and the like. However, if these epoxy resins are used in large amounts, the
) The amount used is limited because it reduces the heat resistance, water resistance, or tack/drape properties of the epoxy resin composition for preg.

The amount of the curing agent diaminodiphenylsulfone used in the present invention should theoretically be 1 equivalent of amine per 1 equivalent of epoxy. In addition, the amount of the curing agent added is preferably in the range of 0.7 to 1.3 equivalents per equivalent of epoxy, depending on the adjustment of the curing speed and shelf life, and the heat resistance and water resistance of the obtained cured product. Equivalent weights can be selected. Furthermore, boron trifluoride/amine complexes, imidazole compounds, dicyandiamide, and the like can also be used as curing accelerators.

The polyether sulfone represented by the general formula [I] used in the present invention was developed by Imperial Chemical Industries Ltd. (UK) and is commercially available under the trade name VICTREX.The amount of this polyether sulfone added is ,
For 100 parts of epoxy resin for prepreg of the present invention, 1
5 to 35 parts is preferred. If the amount exceeds this range, the resulting resin composition will have a very high viscosity, resulting in poor resin impregnation and only prepregs with poor tack tray properties. Further, if the amount is less than this range, the effect of adding polyether sulfone is lost and the toughness becomes low. In addition, in the present invention, [A
It goes without saying that components other than [E] can be used in combination.

There is no particular restriction on the method of mixing each component of the present invention, and a preferred method can be selected as appropriate depending on the properties of the components and the mixing state or dispersion state of the intended blend. An example of a mixing method is a relatively low
There is a method of forming a homogeneous solution at a high temperature, and another example is a method of mixing each component at a relatively high temperature without using a solvent.

In the latter case, a method is preferably used in which the epoxy resin and polyether sulfone are first dissolved at a relatively high temperature, the temperature is lowered, and then the curing agent is mixed.

The epoxy resin composition for prepregs of the present invention is preferably used as a resin for composite materials, and the carbon fibers used in this case include tapes, sheets, mats, textiles, etc. arranged in a certain direction. It can be applied to things like. It can also be used for reinforcing materials of advanced composite materials such as Zara, aramid fibers, boron fibers, silicon carbide fibers, and hybrids of these materials.

[Function] In the present invention, N,N,N'', N-tetraglycidyldiaminodiphenylmethane, N,N,O-triglycidylmethaminophenol, bisphenol F type epoxy resin, diaminodiphenylsulfone and polyethersulfone are combined. provides an epoxy resin composition for prepregs that has excellent toughness, heat resistance, water resistance, and tack/drape properties.In addition, there are no inconveniences in the process of blending each component and the process of impregnating it with reinforcing materials to produce prepreg. A good composite material can be obtained without causing

[Example] The present invention will be explained in more detail by the following example. The base of each component in the examples represents parts by weight, and the contents of the epoxy resin are as follows.

Epoxy A: N, N, N'', N''-tetraglycidyldiaminodiphenylmethane, ELM43 manufactured by Sumitomo Chemical Co., Ltd.
4 Epoxy B: N, N, O-triglycidyl meta-aminophenol, Sumitomo Chemical Co., Ltd. ELM12 Epoxy C: Bisphenol F type epoxy resin, Dainippon Ink & Chemicals Co., Ltd. Epiclon 830 Epoxy D = Bisphenol A type epoxy resin, oil Epicoat 82 manufactured by Kashell Epoxy Co., Ltd.
8 Epoxy E Nibrominated epoxy resin, Dainippon Ink & Chemicals Co., Ltd., Ebikuron 152 Epoxy F: Talesol novolac type epoxy resin Ndau Chemical Japan Co., Ltd. 1lDEN48 Example 1 Epoxy 030 parts, Epoxy 820 parts, Epoxy 030
1 part and 17 parts of polyether sulfone were heated and stirred at 150°C, and a clear viscous liquid was obtained after 30 minutes. When this composition was cooled to 60'C and 46 parts of diaminodiphenylsulfone was uniformly dispersed, a resin composition having appropriate tack and drape properties at room temperature was obtained.

Regarding this resin composition, the viscosity-temperature characteristics were measured using a rheovexy analyzer (manufactured by Wakagi Seisakusho, cone plate type) at a set temperature increase rate of 3° C./min. The minimum viscosity is shown in Table 1.

100 parts of the above resin composition was mixed with a methylene chloride/chloroform/methanol mixed solvent (53/43/4 weight ratio>24
0 parts to prepare a homogeneous solution. This solution was applied to and impregnated onto a plain weave cloth using "Toreca" T300 manufactured by Toshiku Co., Ltd. so that the resin content was 41% by weight.After air drying for 1 day, the solvent was removed by heat drying. A homogeneous prepreg with appropriate tack and drape properties was obtained. 24 sheets of this prepreg were laminated and cured in an autoclave at 180°C for 12 hours at a pressure of 6 to 9/9 to a thickness of approximately 5 mm. ) q.Also, almost no resin flow from the composite material was observed after molding.

Using a plow with a tip radius of 16 mm on this composite material, 680 k
vcm/cm (sample thickness) Drop impact energy was applied. The damage caused by this impact test was measured using an ultrasonic deep damage imaging device @ M400B model manufactured by Canon Holosonics. The damaged area is shown in Table 1.

A resin film was formed on silicon paper using the above resin composition, and this film was
The resin was transferred onto the 2O unidirectionally aligned fibers by heating and pressurizing to a resin weight content of 35%, and was then tacked to a moderate level at room temperature.
A homogeneous unidirectionally aligned prepreg with drapability was obtained. Eight sheets of this prepreg were stacked and cured using an autoclave at 180'C for 2 hours and a pressure of 6ki/cnf to obtain a unidirectional laminate with a thickness of about 11TIIIl.

Using Shimadzu Autograph DO3-101-, the tensile elongation at break in the fiber direction of the composite material was measured at a crosshead speed of 1 mm/min. The results are shown in Table 1.

In the same way, 16 sheets of the above prepreg were stacked to a thickness of about 2 m.
unidirectional laminated material of m) is q. Shimadzu Autograph l5-2
000, the tensile elongation at break in the direction perpendicular to the fibers of the composite material was measured at a crosshead speed of 1 mm/min.

The results are shown in Table 1.

Example 2 A resin composition was prepared in the same manner as in Example 1 using a system in which 26 parts of polyether sulfone was added instead of 17 parts in Example 1, and a resin composition was found to have uniform and appropriate tack and drape properties at room temperature. A resin composition having the following properties was obtained. The viscosity-temperature characteristics of this resin composition were measured in the same manner as in Example 1. The results are shown in Table 1.

When a prepreg was prepared from the above resin composition in the same manner as in Example 1 using a mixed solvent of methylene chloride/chloroform/methanol, this prepreg had appropriate tack/drape properties at room temperature. This prepreg was subjected to a hammer impact test in the same manner as in Example 1, and the damaged area was measured. The results are shown in Table 1.

Using the above resin composition, a homogeneous unidirectional prepreg having appropriate tuck and drape properties at room temperature was obtained in the same manner as in Example 1.

Using this prepreg, the tensile elongation at break in the fiber direction and in the direction perpendicular to the fibers was measured in the same manner as in Example 1. The results are shown in Table 1.

Moreover, almost no resin flow from the composite material was observed after molding.

Example 3 A resin composition was prepared in the same manner as in Example 1 using a system in which 31 parts of polyether sulfone was added instead of 17 parts in Example 1, and it showed uniform and appropriate tack and drape properties at room temperature. A resin composition having the following properties was obtained. The viscosity-temperature characteristics of this resin composition were measured in the same manner as in Example 1. The results are shown in Table 1.

When a prepreg was prepared from the above resin composition in the same manner as in Example 1 using a mixed solvent of methylene chloride/chloroform/methanol, this prepreg had appropriate tack/drape properties at room temperature. Using this prepreg, by the same method as in Example 1,
The damaged area was measured after the hammer impact test. The results are shown in Table 1. In addition, almost no resin flow from the composite material was observed in the first molding process.

Example 4 40 parts of epoxy A, 830 parts of epoxy, 30 parts of epoxy
A resin composition was prepared in the same manner as in Example 1 using a system consisting of 34 parts of polyether sulfone, and 36 parts of diaminodiphenylsulfone. As a result, a resin composition having uniform and appropriate tack and drape properties at room temperature was obtained. I was given 1q.

The viscosity-temperature characteristics of this resin composition were measured in the same manner as in Example 1. The results are shown in Table 1.

When a prepreg was prepared from the above resin composition in the same manner as in Example 1 using a mixed solvent of methylene chloride/chloroform/methanol, this prepreg had appropriate tack/drape properties at room temperature. Using this prepreg, by the same method as in Example 1,
The damaged area was measured after the hammer impact test. The results are shown in Table 1. Furthermore, almost no resin flow from the composite material was observed after molding.

When the above resin composition was cured at 180'C for 2 hours, a transparent cured resin product was obtained. The glass transition temperature (measured using a differential calorimeter at a heating rate of 40'C/min) of this cured resin is 205°C, and the water absorption rate (boiling/20 hours) is 2.5%. Similarly, a cured resin plate was prepared with the same composition as above without adding polyether sulfone.The glass transition temperature of this plate was 205°.
C, and the water absorption rate was 3.0%.

From this example, it was revealed that a cured resin product having excellent heat resistance and water resistance and in which polyether sulfone was homogeneously dispersed could be obtained.

Example 5 60 parts of epoxy A, 820 parts of epoxy, 20 parts of epoxy
A resin composition was prepared in the same manner as in Example 1 using a system consisting of 17 parts of polyether sulfone, and 45 parts of diaminodiphenylsulfone. As a result, a resin composition having uniform and appropriate tack and drape properties at room temperature was obtained. Obtained.

The viscosity-temperature characteristics of this resin composition were measured in the same manner as in Example 1. The results are shown in Table 1.

When a prepreg was prepared from the above resin composition in the same manner as in Example 1 using a mixed solvent of methylene chloride/chloroform/methanol, this prepreg had appropriate tack/drape properties at room temperature. Using this prepreg, by the same method as in Example 1,
The damaged area was measured after the hammer impact test. The results are shown in Table 1. Furthermore, almost no resin flow from the composite material was observed after molding.

Comparative Example 1 A resin composition was prepared in the same manner as in Example 1 using a system consisting of 60 parts of epoxy A, 840 parts of epoxy, 30 parts of diaminodiphenylsulfone, and 33 parts of polyether sulfone. The resin composition was increased by 1.

The viscosity-temperature characteristics of this resin composition were measured in the same manner as in Example 1. The results are shown in Table 1.

When a prepreg was produced from the above resin composition in the same manner as in Example 1 using a mixed solvent of methylene chloride/chloroform/methanol, 1 q of prepreg was obtained that had no tack/drape properties at room temperature. Using this prepreg, the damage area in the hammer drop impact test was measured in the same manner as in Example 1. The results are shown in Table 1. Furthermore, almost no resin flow from the composite material was observed after molding.

Comparative Example 2 50 parts of epoxy A, 820 parts of epoxy, 030 epoxy
The viscosity-temperature characteristics of a resin composition consisting of 1 part and 46 parts of diaminodiphenylsulfone were measured in the same manner as in Example 1. The results are shown in Table 1.

Add 100 parts of the above resin composition to 150 parts of methyl ethyl ketone.
to prepare a homogeneous solution. A composite material having a thickness of approximately 5 mm was obtained from this solution in the same manner as in Example 1. After molding, significant resin flow was observed from the composite. Using this composite material, the damaged area after the hammer impact test was measured in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3 Epoxy A 35 parts, Epoxy 030 parts, Epoxy 030
The viscosity-temperature characteristics of a resin composition consisting of 1 part and 34 parts of diaminodiphenylsulfone were measured in the same manner as in Example 1. The results are shown in Table 1.

Add 100 parts of the above resin composition to 150 parts of methyl ethyl ketone.
to prepare a homogeneous solution. A composite material having a thickness of approximately 5 mm was obtained from this solution in the same manner as in Example 1. Using this composite material, the damaged area after the hammer impact test was measured in the same manner as in Example 1. The results are shown in Table 1.

A unidirectional laminate was produced using the above resin composition in the same manner as in Example 1, and the tensile elongation at break in the fiber direction and in the direction perpendicular to the fibers was measured. The results are shown in Table 1.

In addition, remarkable resin flow was observed in the composite material obtained in this example after molding.

Comparative Example 4 63 parts of epoxy A, 817 parts of epoxy, 22 parts of epoxy
The viscosity and temperature characteristics of a resin composition consisting of 1 part and 45 parts of diaminodiphenylsulfone were measured in the same manner as in Example 1. The results are shown in Table 1.

Add 100 parts of the above resin composition to 150 parts of methyl ethyl ketone.
to prepare a homogeneous solution. Using this solution,
A composite material having a thickness of approximately 5 mm was obtained in the same manner as in Example 1. Using this composite material, the damaged area after the falling weight impact test was measured in the same manner as in Example 1. The results are shown in Table 1.

A unidirectional laminate was produced using the above resin composition in the same manner as in Example 1, and the tensile elongation at break in the fiber direction and in the direction perpendicular to the fibers was measured. The results are shown in Table 1.

In addition, remarkable resin flow was observed in the composite material obtained in this example after molding.

[Effect of the invention] (1) Damage to composite materials due to impact is reduced.

(2) A resin composition with excellent heat resistance and water resistance is provided.

(3) A prepreg with stable quality and excellent tuck and drape properties can be produced.

(4) A homogeneous resin composition and cured resin are obtained.

(5) Can be molded using an autoclave without requiring special conditions.

(6) The tensile elongation at break in the direction perpendicular to the fibers of the unidirectional laminated material is improved, and 1q of homogeneous multidirectional laminated materials can be obtained.

(7) Since the minimum viscosity is increased and the resin flow during molding is small, it is possible to mold a composite material with a uniform thickness.

Claims (1)

[Scope of Claims] As an essential component, [A] N,N,N',N'-tetraglycidyldiaminodiphenylmethane [B] N,N,O-triglycidylmethaminophenol [C] Bisphenol F-type epoxy resin [ D] Diaminodiphenylsulfone [E] General formula ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ [I] An epoxy resin composition for prepregs containing polyether sulfone shown by [I].