JPH01129A - Interleaf-containing fiber-reinforced epoxy resin prepreg material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an interleaf-containing fiber-reinforced epoxy resin prepreg material, more specifically, it contains a surface-treated polyimide film as an interleaf,
The present invention relates to a fiber-reinforced epoxy resin prepreg material that can produce a laminated composite material that has high glabella shear strength, bending fracture strength, deflection amount, etc., and has high strength and high toughness.

(Prior Art and its Problems) Fiber-reinforced epoxy resin composite materials have high specific strength and specific modulus, and are therefore widely used in everything from sporting goods to structural materials for aircraft. In particular, regarding carbon fiber reinforced resin (CFRP) for aircraft, epoxy resin matrix composite materials containing tetraglycidylamino diphenylmethane (TGDDM)/diaminodiphenylsulfone (DO3) as main components are often used.

These composite materials are widely used because they have excellent heat-and-moisture (hot/wet) resistance, which is particularly required as structural materials for aircraft, but they generally lack toughness and have problems in impact resistance.

Various improvements have been made to overcome these drawbacks.

For example, surface treatment of fibers and modification (toughening, etc.) of epoxy resins have been carried out, but it is known that it is difficult to maintain a balance with heat and humidity resistance.

Additionally, attempts have been made to stitch prepreg laminates, but this method is unsuitable for complex, large-sized products and is impractical.

Under these circumstances, the concept of prepreg with Interleaf Fi disclosed in Japanese Patent Application Laid-open Nos. 60-63229 and 60-231738 is a new technology that overcomes the above drawbacks. There is one. However, these inventions also have problems such as insufficient moisture and heat resistance of the interleaf layer and difficulty in forming a uniform thin resin layer by coating.

Furthermore, JP-A-60-231738 also describes an interleaf of thermoplastic resin, and mentions in it that a polyimide film is used as the interleaf. These are suitable as interleaves because they are thin films with uniform thickness and have excellent moisture and heat resistance.

The prepreg material having the above-mentioned interleaf is generally
It is manufactured by pressing fiber-reinforced epoxy resin prepreg and interleaf at the B-stage (a state in which the liquid thermosetting resin is polymerized to the point of drying).
When the above-mentioned interleaf is used, the adhesive force between the above-mentioned epoxy resin prepreg and the interleaf is insufficient.

Therefore, although composite materials obtained from prepreg materials having such interleaves or by laminating prepreg materials have improved toughness, they have poor mechanical strength such as tensile strength, bending strength, and interlaminar shear strength. has not improved and is unsatisfactory.

(Objective of the Invention) An object of the present invention is to provide a fiber-reinforced epoxy resin prepreg material that can produce a composite material that has excellent mechanical strength such as interlaminar shear strength and bending fracture strength, and also has high toughness. do.

The present invention further provides a fiber-reinforced epoxy resin prepreg material that is extremely homogeneous and uniform, can be easily produced industrially, and can be laminated to produce composite materials of large size and complex shapes. The purpose is to

(Structure of the Invention) The present invention is an interleaf-containing fiber-reinforced epoxy resin prepreg material characterized by containing a fiber-reinforced epoxy resin matrix and an interleaf made of a polyimide film treated with corona discharge and/or matted. .

(Preferred Embodiment of the Invention) The interleaf in the present invention is a surface-treated polyimide film formed from a polymer having an imide skeleton. Examples of the structural formula of the imide skeleton include Q 0 . In particular, a polyimide film (manufactured by Ube Industries, Ltd., Ubilex R) having an imide skeleton represented by the structural formula has a large tensile elongation at break and is therefore desirable as it exhibits excellent effects.

Such a film is disclosed, for example, in Japanese Patent Application Laid-Open No. 50-1135.
Publication No. 97, Publication No. 55-27328, Publication No. 55-28
It is manufactured by the method disclosed in Japanese Patent No. 822, Japanese Patent No. 55-65227, and the like.

The thickness of the polyimide film is less than or equal to the thickness of the fiber-reinforced epoxy prepreg shown in FIG.
0 μm, particularly preferably 10 to 30 μm. 5 μm
If it is thinner, it is difficult to manufacture and economically disadvantageous. Further, if the thickness is more than 40 μm, it is difficult to achieve the object of the present invention.

The surface treatment means for the polyimide film is corona discharge treatment, matte finishing, or a combination treatment of both.

Although methods for corona discharge treatment of general thermoplastic resin films are conventionally known, corona discharge treatment of polyimide films as described above is completely unknown. However, for example,
Publication No. 32-10614, Publication No. 32-1061
The above-mentioned polyimide film can be subjected to corona discharge treatment by a method known per se as disclosed in Japanese Patent No. 5 and the like. Particularly preferable corona discharge treatment conditions for a polyimide film in the present invention vary depending on the width and thickness of the film, processing speed, etc., but generally the discharge amount expressed as the power value per unit time and unit area is 30 to 1.
It is to be within the range of 50 W/m'·min. By subjecting the surface of the polyimide film to corona discharge treatment, polar groups (for example, -
OH group, -C0OH group, -C-O group, etc.),
The chemical affinity of the polyimide film to the epoxy resin can be increased, and as a result, the adhesiveness between the polyimide film and the epoxy resin prepreg can be improved.

Further, as a method for matting a polyimide film, a method known per se may be used, for example, Japanese Patent Publication No. 38-118
The method disclosed in Japanese Patent No. 38 can be adopted. That is, microparticles of inorganic substances or metals having appropriate hardness such as sand, titanium oxide, carborundum, calcium carbonate, etc. are strongly blown onto the surface of a polyimide film together with compressed air, so that the surface of the film is not physically damaged. The film is matted, then washed with water and dried with hot air to obtain a matted polyimide film. The surface roughness of the matte film is between 0゜l and 0.6μ
It is preferable to perform matte processing until the center line average roughness (Ra) is in the range of m.

An anchoring effect occurs between the matted polyimide film and the epoxy resin, and the adhesiveness with the epoxy resin prepreg becomes high.

When the above-mentioned corona discharge treatment and matte processing are used in combination, the adhesiveness between the polyimide film and the epoxy resin prepreg becomes even higher. Either corona discharge treatment or matte processing may be performed first.

Furthermore, even if the above surface treatment is performed on only one side of the polyimide film, since the film is thin, the surface treatment effect will also appear on the untreated side, improving the adhesion of the film to the epoxy resin prepreg. .

Of course, if both sides of the polyimide film are surface treated, the adhesion will be further improved.

The fiber reinforced epoxy resin matrix in the present invention is
This prepreg is made by impregnating reinforcing fibers with epoxy resin.

The reinforcing fibers used in the present invention include glass fiber, P
AN-based carbon fiber, pitch-based carbon fiber, aramid fiber, alumina fiber, silicon carbide fiber, and S
i -T i -C-O fiber (Tyranno fiber, manufactured by Ube Industries, Ltd.), and two or more of these fibers can be used in combination.

Moreover, in addition to being used in a form in which these materials are aligned in one direction, they can also be used as a woven fabric. These fibers may be subjected to known surface treatments and sizing treatments.

The epoxy resin used in the present invention is polyepoxide,
Consists of curing agent, curing catalyst, etc.

Polyepoxide is a compound having on average one or more epoxy groups in the molecule, and this epoxy group may be present as a terminal group or may be present within the molecule. These are saturated or unsaturated aliphatic,
It may be a cycloaliphatic, aromatic, or heterocyclic compound, and may also be a compound containing a halogen atom, a hydroxyl group, an ether group, or the like.

Examples include glycidyl compounds of bisphenols A, B and S, glycidyl compounds of talesol novolak or phenol novolak, glycidyl compounds of aromatic amines and cycloaliphatic polyepoxides.

Specific examples of such polyepoxides include 1.4-
Bis(2,3-epoxypropoxy)benzene, 4.4
'-bis(2,3-epoxypropoxy)diphenyl ether.

Another example is the glycidyl compound of polyhydric phenol.

Polyhydric phenols used for this purpose include, for example, resorcinol, catechol, hydroquinone, 2.3-bis(4-hydroxyphenyl)propane (bisphenol A), 2.2-bis(4-hydroxyphenyl)butane, bis( 4-hydroxyphenyl) sulfone (bisphenol-3), bis(4-hydroxyphenyl)methane, tris(4-hydroxyphenyl)methane, 3゜9-
bis(3-methoxy,4-hydroxyphenyl)-2,
4,8,10-tetraoxaspiro(5,5)undecane, as well as 2,2-bis(
These include 4-hydroxytetrabromophenyl)propane.

Another example of a polyepoxide is a glycidyl compound of a polyhydric alcohol.

Examples of polyhydric alcohols that can be used for this purpose include glycerol, ethylene glycol, pentaerythritol, and 2,2-bis(4-hydroxylcyclohexyl)propane.

Examples of Bot epoxides with internal epoxy groups include:
4-(1,2-epoxyethyl)-1゜2-epoxycyclohexane, bis(2,3-epoxycyclobentyl)ether, 3.4-diboxycyclohexylmethyl-
(3,4-epoxy)cyclohexanecarboxylate and the like.

Another example of a polyepoxide is a glycidyl compound of an aromatic amine.

Aromatic amines that can be used for this purpose include diaminodiphenylmethane, metaxylene diamine, m-aminophenol, p-aminophenol, and the like.

Among these polyepoxides, diglycidyl ether of bisphenol A, glycidyl compounds of talesol novolak or phenol novolak, glycidyl compounds of diaminodiphenylmethane, and glycidyl compounds of aminophenol are preferably used.

These polyepoxides may be used alone or in combination of two or more.

Specifically, the curing agent used in the present invention includes 0-
phenylenediamine, m-phenylenediamine, 4.4
Aromatic polyamines such as '-methylene dianiline, 4゜4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-xylene diamine, triethylenetetramine, diethylenetriamine, isophoronediamine, 1,3-diaminocyclohexanemethane Polyamines such as aliphatic polyamines such as diamine, cyanoethylated diethylenetriamine, N-amino-ethylpiperazine, methyliminobispropylamine, aminoethylethanolamine, polyetherdiamine, polymethylenediamine, phthalic anhydride, succinic anhydride, anhydride Maleic anhydride of maleic acid, hexahydrophthalic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, trimellitic anhydride, itaconic anhydride, citraconic anhydride, dodecenylsuccinic anhydride, florendic anhydride, methylcyclopentadiene anhydride Polycarboxylic acids such as acid adducts, methyltetrahydrophthalic anhydride, toluic acid adducts of maleic anhydride, cyclopentanetetracarboxylic anhydride, alkylated endoalkylenetetrahydrophthalic anhydride, ethylene glycol bistrimetite, glycerin tristrimetite, etc. acidic substances having a group, a polycarboxylic acid anhydride group, or a mixed group thereof,
Isophthalic acid dihydrazide, adipic acid dihydrazide,
Examples include hydrazides such as sebacic acid dihydrazide, polyamides, dicyandiamide, and ketimine.

In addition, as a curing catalyst, trifluoride such as boron trifluoride monoengineered tylamine complex compound, boron trifluoride piperidine complex compound, etc.
Imidazole compounds such as boron trifluoride complex, 2-ethylimidazole, 2-ethyl 4-ethylimidazole,
triphenyl phosphite, butanetetracarboxylic acid,
1.8 Diaza-bicyclo-(5,4,O)-undecene-7,N-(3-chloro-4-methoxyphenyl)-N
, N'-dimethylurea, N-(3-chloro-4methylphenyl)-N', N'-dimethylurea, N-(
3,4-dichlorophenyl)-N', N'-dimethylurea, N-(4-ethoxyphenyl)-N', N'-
Examples include urea compounds such as dimethylurea, N-(4-methyl-3nitrophenyl)-N', and N'-dimethylurea.

Generally, the combination and quantitative ratio of the polyepoxide and curing agent described above should be close to the stoichiometric amount, and if a curing catalyst is included, the curing agent may be used in a slightly lower amount than the stoichiometric amount. desirable.

Moreover, various thermoplastic resins can also be added to these polyepoxides. Specific examples include polyesters such as poly(ε-caprolactone), polybutadiene, polybutadiene/acrylonitrile copolymers optionally containing amine, carboxyl, hydroxyl, or -5H groups, poly(ethylene terephthalate), poly(butylene terephthalate), Polyetherimide, acrylonitrile/
Butadiene/styrene copolymer, polyamides such as nylon 6, nylon 6.6, nylon 6.12, and copolymers thereof, poly(amideimide), polyolefin, polyethylene oxide, polybutyl methacrylate, impact resistance polyarylates such as modified polystyrene, sulfonated polyethylene, bisphenol A1 isophthalic acid, polyarylates derived from terephthalic acid,
Poly(2,-6-dimethylphenylenoxide), polyvinyl chloride and copolymers thereof, polyacetal, polyphenylene sulfide, etc. In addition, it is also possible to mix thermosetting resins with excellent heat resistance such as bismaleimide and polyimide.

It is also possible to modify the polyepoxide to improve its adhesion to the polyimide film.

The interleaf-containing fiber-reinforced epoxy resin prepreg material of the present invention has, for example, a structure as shown in the accompanying drawings.

Fig. 1 is a cross-sectional view of a pre-reg material consisting of one layer of interleaf and one layer of fiber-reinforced epoxy resin matrix, and Fig. 2 shows a laminate in which interleaf and fiber-reinforced epoxy resin matrix are alternately laminated and crimped. It is a sectional view of one example of prepreg material. In FIGS. 1 and 2, 1 is an interleaf and 2 is a fiber-reinforced epoxy resin matrix.

As a method for manufacturing the prepreg material of the present invention, a method known per se can be employed, except for using a polyimide film treated with corona discharge and/or matted as an interleaf.

That is, for example, it is a method of manufacturing the prepreg material of the present invention by press-bonding a B-stage fiber-reinforced epoxy resin prepreg and an interleaf. Another method is to manufacture a prepreg material by press-bonding an interleaf and a fiber-reinforced epoxy resin that has not yet been B-staged and then heating the epoxy resin to B-stage the epoxy resin.

In the former method, the fiber-reinforced epoxy resin prepreg can be produced by pulling a large number of filament yarns of the reinforcing fibers in one direction to form a prepreg, or by winding the filament yarn impregnated with the epoxy resin around a drum to form a prepreg. A method in which a large number of filament threads are drawn together and then melted and impregnated with a film-like resin to form a prepreg.A method in which a woven fabric or non-woven fabric is introduced into a resin reservoir, impregnated and dried, A sheet-shaped resin is applied to a woven fabric or non-woven fabric Known methods include a method of melt impregnation to form a prepreg.

In addition, as a variation of the latter method, the interleaf and the epoxy resin containing no fibers before B-stage are crimped together, the epoxy resin is impregnated with reinforcing fibers, and then heated to transform the epoxy resin into a B-stage. There is also a way to stage it.

In the above method, the prepreg material of the present invention as shown in FIG. can be manufactured.

Further, a prepreg material as shown in FIG. 2 can be manufactured by laminating a plurality of prepreg materials as shown in FIG. 1.

Furthermore, the method of forming a composite material from a laminate of prepregs containing interleaf is not limited in any way, and may be formed by vacuum bag/autoclave curing method, hot press molding, sheet winding method, etc. May be molded. Typical curing temperature is 130℃
~180°C. Moreover, curing time, pressure, etc. can be selected appropriately, and pre-curing and post-curing can also be performed.

(Effects of the Invention) The interleaf-containing fiber-reinforced epoxy resin prepreg material of the present invention uses a polyimide film with excellent mechanical properties such as heat resistance, tensile strength, and tensile elongation at break as the interleaf, and further specifies the polyimide film. Since the surface is treated by the above method, the adhesive force between the polyimide film and the fiber-reinforced epoxy resin matrix is strong. Therefore, the composite material manufactured from the prepreg material of the present invention has high interlaminar shear strength, bending fracture strength, etc. It has the remarkable effect of having excellent mechanical strength and high toughness.

Furthermore, the prepreg material of the present invention is extremely homogeneous and uniform, and can be easily produced industrially, and by laminating it, large-sized and complex-shaped composite materials can be produced. This has the remarkable effect of making it possible to

Next, Examples and Comparative Examples of the present invention will be shown. In each Example and Comparative Example, mechanical properties were measured by the following method.

(1) Measuring device: Toyo Baldwin, Tensilon 5T (2) Bending test: Three-point bending method, span/thickness ratio of 40, crosshead speed of 2 mm and 7 minutes. Temperature: 23° C. Humidity: 50% RH0 (3) Interlaminar shear strength: The short beam method was used at a span/thickness ratio of 4 and a crosshead speed of 2 mm for 7 minutes. Temperature 23℃, humidity 50%RH.

Example I N,N%N',N'-Tetraglycidylaminodiphenylmethane (200g) and 4,4'-diaminodiphenylsulfone two oog were mixed, and these resin compositions were dissolved in methyl ethyl ketone to make a 60% solution. .

This resin solution was impregnated into a carbon fiber filament yarn (Bestphyte lTA3000° manufactured by Toho Rayon ■) drawn in one direction and wound onto a drum wrapped with Teflon release paper.

These resin-impregnated fibers were cut open with a cutter and heated at 120° C. for 5 to 15 minutes in a hot air circulation dryer to produce prepregs.

The obtained prepreg had a thickness of 300 μm and a fiber volume content of 62%. This prepreg is 90mmx
It was cut into a size of 260 mm.

On the other hand, both sides of a polyimide film (manufactured by Ube Industries, Ltd., Ubilex R1, thickness 7.5 μm) were subjected to a discharge amount of 50 W/m 2 using a high frequency power supply (corona surface treatment machine) (manufactured by Kasuga Electric Co., Ltd.). - After corona discharge treatment under conditions of min., it was cut into a size of 90 mm x 260 mm.

A prepreg containing an interleaf as shown in FIG. 1 was prepared by laminating the above prepreg and a polyimide film treated with corona discharge.

Six pieces of this interleaf-containing prepreg were laminated in the 0° direction and press-molded at 180° C. under a pressure of 7 g/cm 2 for 2 hours. The composite material was then boil cured in an oven at 190° C. for 5 hours.

From this composite material, a wire with a length of 85 mm and a width of 12.7 mm was made.
1 bending test piece and an O with a length of 28 mm and a width of 12.7 mm.
A test piece for interlaminar shear was cut out. Using these test pieces, the bending breaking strength, the amount of deflection at bending breaking, and the glabella shear strength i were measured. The results are shown in Table 1.

Example 2 A composite material was produced in the same manner as in Example 1, except that the polyimide film was changed to one having a thickness of 12.5 μm, and its physical properties were measured. The results are shown in Table 1.

Example 3 The polyimide film was changed to one with a thickness of 25 μm, and the corona discharge treatment of the polyimide film was applied to matte processing (Ra
: 0.2 to 0.3 μm), but the same as Example 1.
A composite material was manufactured in the same manner as in , and its physical properties were measured. The results are shown in Table 1.

Example 4 A composite material was produced in the same manner as in Example 3, except that a polyimide film that had been subjected to a corona discharge treatment in the same manner as in Example 1 was used after the matte processing of the polyimide film, and its physical properties were determined. was measured. The results are shown in Table 1.

Comparative Example 1 A composite material was produced in the same manner as in Example 1, except that the polyimide film interleaf was not used and the lid was not used, and its physical properties were measured. The results are shown in Table 1.

Comparative Example 2 A composite material was produced in the same manner as in Example 1, except that the polyimide film was not subjected to corona discharge treatment, and its physical properties were measured. The results are shown in Table 1.

Comparative Example 3 A composite material was produced in the same manner as in Example 2, except that the polyimide film was not subjected to corona discharge treatment, and its physical properties were measured. The results are shown in Table 1.

Comparative Example 4 A composite material was produced in the same manner as in Example 3, except that the polyimide film was not matted, and its physical properties were measured. The results are shown in Table 1.

Example 5 A prepreg containing an interleaf was prepared in exactly the same manner as in Example 1 except that the thickness of the prepreg was changed from 300 μm to 140 μm. This prepreg was laminated in 15 plies in the 0° direction and autoclaved for 6 hours at a maximum temperature of 180° C. and a maximum pressure cuff of 8 g/cm 2 . The composite material was then bostkineared in an oven at 190'C for 5 hours. A 0-layer interlaminar shear test piece with a length of 28 mm and a width of 12.7 mm and a 0° bending test piece with a length of 85 mm and a width of 12.7 mm were cut out from this composite material.

The load-deflection curves for both tests are shown in FIGS. 3 and 4.

Comparative Example 5 The same procedure as in Example 5 was performed except that the polyimide film interleaf was not used, and the resulting load-deflection curves are shown in FIGS. 3 and 4.

From the above Example 5 and Comparative Example 5, it can be seen that the composite material obtained from the prepreg of the present invention has high strength and high toughness. It is also clear from FIGS. 3 and 4 that delamination is less likely to occur in the composite material obtained from the prepreg of the present invention.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a prepreg material consisting of one layer of interleaf and one layer of fiber-reinforced epoxy resin matrix, and Fig. 2 shows a laminate in which interleaf and fiber-reinforced epoxy resin matrix are alternately laminated and crimped. FIG. 3 shows the load-deflection curve during the 0° interlaminar shear test of the unidirectional laminated composite material, and FIG. 4 shows the load-deflection curve during the 0° bending test of the -direction laminated composite material. The load-deflection curve is shown. 1 is an interleaf, and 2 is a fiber-reinforced epoxy resin matrix. Figure 1 Procedural Amendment (Elephant) May 11, 1988 Kunio Ogawa, Commissioner of the Patent Office, Indication of the case, Patent Application No. 28906, filed in 1989 2, Name of the invention Interleaf-containing fiber-reinforced epoxy resin prepreg Material 3. Relationship with the case of the person making the amendment Patent applicant 4. Agent 〒105 5. Date of amendment order 7. Contents of amendment (1) Figure 3 is corrected as shown in the attached sheet. 3 figures each

Claims (1)

[Claims] (1) An interleaf-containing fiber-reinforced epoxy resin prepreg material comprising a fiber-reinforced epoxy resin matrix and an interleaf made of a polyimide film treated with corona discharge and/or matted.