JPH01148546A - Fiber-reinforced resin laminated material - Google Patents

Abstract

PURPOSE:To improve bending properties, by a method wherein a laminated material is constituted so that one side of the outermost layers of the laminated material is constituted of a prepreg layer containing a carbon fiber and the other side of the outermost layers of the laminated material is constituted of a prepreg layer containing an inorganic fiber constituted of each element of Si, Ti or Zr, C and O. CONSTITUTION:Carbon fiber prepreg, which is in a semi-cured state and arranged unidirectionally, is prepared by a method wherein a carbon fiber is impregnated with epoxy resin, then the same is wound round a drum winder unidirectionally for heating. Inorganic fiber prepreg, which is in the semi-cured state and arranged unidirectionally, is prepared similarly by making use of inorganic fiber prepreg comprised of Si, Ti or Zr, C and O. Bending properties of a laminated material is improved by a method wherein those two kinds of the prepreg are superposed upon each other by making one side of a surface layer a prepreg layer containing the carbon fiber and the other side of the same a prepreg layer containing the inorganic fiber and press lamination is performed at 100-250 deg.C.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a prepreg having particularly excellent bending properties, which is manufactured by laminating prepregs in which carbon fibers and specific inorganic fibers are each impregnated with a thermosetting resin. This invention relates to a fiber reinforced resin laminate.

(Prior art and its problems) Carbon fiber-reinforced plastic composites have high specific strength and specific modulus, and are therefore used in sports and leisure goods. However, this material has technical problems such as low compressive strength or bending strength, low elongation and brittleness.

Therefore, attempts have been made to eliminate the above-mentioned problems by using a so-called hybrid laminate material that combines a carbon fiber layer and another fiber layer. Conventionally, glass fibers and aramid fibers have been preferably used as fibers to be combined with carbon fibers. However, glass fiber has the problem of low strength and elastic modulus, and is also heavy.
Aramid fibers have a problem of high elongation but low compressive strength and easy moisture absorption. Therefore, it is difficult to say that a plastics composite material obtained by using a combination of these fibers and carbon fibers is a material that is practically satisfactory.

JP-A-62-7737 discloses that Si, Ti or Zr
, a composite material obtained by laminating prepregs impregnated with plastics on inorganic fibers and carbon fibers each composed of the elements C and 0, and pressurizing and heating this laminate,
So-called interlayer hybrid composites have been disclosed. This composite material takes advantage of the excellent features of the above-mentioned inorganic fibers, namely good adhesion with the matrix resin and flexibility of the fibers themselves, and has a higher tensile strength than carbon fiber reinforced plastic composite materials. Excellent in interlaminar shear strength and Charpy impact strength.

In recent years, inorganic fiber-reinforced plastic composite materials are required to have not only the above-mentioned excellent strength but also high bending properties. From this point of view, it is difficult to say that the composite material described in the above-mentioned publication has sufficient bending properties as shown in the examples of the publication.

(Object of the Invention) The object of the present invention is to provide a laminate that maintains the advantages of the glabella hybrid laminate described in JP-A-62-7737, while improving its bending properties, which is its biggest problem. It's about doing.

(Technical Means for Solving the Problems) The above object of the present invention is to apply a thermosetting resin to each of the carbon fibers and the inorganic fibers substantially composed of the elements Sl, T1 or Zr, C and O. In a fiber-reinforced resin laminate manufactured by laminating prepreg impregnated with carbon fiber, one of the outermost layers of the laminate is composed of the carbon fiber-containing prepreg layer, and the other is composed of the inorganic fiber base with the prepreg layer. This is achieved by a fiber-reinforced resin laminate material characterized by the following structure.

The carbon fiber in the present invention may be one using any of polyacrylonitrile, petroleum pitch, and coal pitch as its precursor. Further, it may be either carbonaceous fiber or graphite fiber, which are called depending on the firing temperature.

The inorganic fiber in the present invention is US Patent No. 434271.
It can be prepared according to the method described in Specification No. 2 and Specification No. 4515742, the descriptions of which are incorporated herein by reference.

An example of the preparation method is shown below.

A polycarbosilane with a number average molecular weight of 200 to 10,000 having a main chain skeleton represented by the formula R →Si CHz→- (wherein R in the formula represents a hydrogen atom, a lower alkyl group, or a phenyl group), and the formula MX4 (However, M in the formula represents Ti or Zr, and X has a carbon number of 1
~20 alkoxy groups, phenoxy groups, or acetylacetoxy groups) is combined with the total number of -Ji-CH2+- structural units of the polycarbosilane to 4 to 0 valves of the above organometallic compound. The total number of structural units of the polycarbosilane is added in a quantitative ratio such that the ratio of the total number of structural units is within the range of 2:2 to 200:1, and the polycarbosilane is heated and reacted in an inert atmosphere to remove at least one of the silicon atoms of the polycarbosilane. A first step in which a part of the organometallic compound is bonded to a metal atom of the organometallic compound via an oxygen atom to produce an organometallic copolymer having a number average molecular weight of 700 to 100,000, and a spinning stock solution of the above copolymer is prepared. A manufacturing process consisting of a second step of spinning, a third step of making the spun fibers infusible, and a fourth step of firing the infusible spun fibers in a vacuum or in an inert gas atmosphere at a temperature range of 800 to 1500°C. The inorganic fibers of the present invention can be obtained by the method.

The proportions of each constituent element in the inorganic fiber are: Si: 30-60% by weight, Ti or Zr: 0.5-35% by weight, preferably 1-1
0% by weight, C: 25-40% by weight, 0: 0.01-30% by weight.

The ratio of inorganic fibers to the total of inorganic fibers and carbon fibers is preferably 1 to 80% by volume, particularly 3 to 70% by volume. If the above proportion is less than 1% by volume, the effect of improving the bending properties of the laminated material is small, and if it is greater than 80% by volume, the proportion of carbon fiber decreases relatively, and the high tensile strength and lightweight properties of carbon fiber are added to the laminated material. It becomes difficult to grant.

The total proportion of carbon fibers and inorganic fibers in the laminate is usually 30 to 80% by volume, preferably 45 to 65% by volume.

Although carbon fibers and inorganic fibers are preferably used in the form of unidirectionally aligned fibers, they can also be used in the form of a woven fabric (fabric) formed by weaving the respective fibers.

Further, both fibers may be subjected to known surface treatment and sizing treatment.

The thermosetting resin in the present invention is not particularly limited, and examples include epoxy resin, unsaturated polyester resin, vinyl ester resin, phenol'MML bismaleimide resin, and polyimide resin. Among these resins, epoxy resins are preferably used. The above-mentioned epoxy resin is a resin composition consisting of polyepoxide, a curing agent, a curing catalyst, and the like.

Examples of polyepoxides include bisphenol A,
Examples include glycidyl compounds of F and S, glycidyl compounds of talesol novolak or phenol novolak, and alicyclic polyepoxides.

Other examples of polyepoxides include glycidyl compounds of polyhydric phenols, polyhydric alcohols or aromatic amines.

Among these polyepoxides, the glycidyl ether of bisphenol A, the glycidyl compound of talesol novolac or phenol novolank, the glycidyl compound of diaminodiphenylmethane, and the glycidyl compound of aminophenol are generally used. In addition, when the laminate material of the present invention is used as a member requiring high functionality such as a primary structural material of an aircraft, among the above polyepoxides,
Preference is given to using glycidyl compounds of polyfunctional amines such as diaminodiphenylmethane.

The laminate of the present invention is manufactured by laminating prepregs in which carbon fibers and inorganic fibers are each impregnated with a thermosetting resin, and then curing the thermosetting resin.

Methods for preparing prepreg include a method in which a large number of filament threads made of the above-mentioned fibers are aligned in one direction and sandwiched between thermosetting resins to make a prepreg, and a bundle of filament threads impregnated with thermosetting resin is wound around a drum. A method of preparing prepreg by pulling a large number of filament threads together and then melting and impregnating them with a thermosetting resin film. A method of introducing a woven or nonwoven fabric into a thermosetting resin reservoir, impregnating it, and drying it. Methods known per se can be appropriately employed, such as a method of preparing a prepreg by melting and impregnating a sheet-like material made of a thermosetting resin into a woven or nonwoven fabric.

In the present invention, when laminating the above-mentioned prepregs, it is necessary to make one of the outermost layers (surface layers) of the laminated material a carbon fiber-containing prepreg layer and the other one an inorganic fiber-containing prepreg layer. By laminating the prepregs as described above, when static bending or dynamic overcurrent is applied to the laminated material of the present invention, the outermost layer where the maximum compressive stress occurs is an inorganic fiber-reinforced resin with excellent compressive properties. By arranging the layers and placing a carbon fiber-reinforced resin layer with excellent tensile properties on the other outermost layer where the maximum tensile stress occurs, the bending properties of the entire laminate can be significantly improved. . If both outermost layers of the laminate are made of prepreg layers using one or the other fiber, the flexural properties of the laminate, such as static or dynamic bending strength or Charpy impact strength, cannot be significantly improved. .

There are no particular restrictions on the method of laminating prepreg.
All known methods such as hand layup method and automatic layup method can be employed.

There are no particular limitations on the stacking form, configuration, order, and repeating thickness of the prepreg, except for the configuration of the outermost layer described above.

The method of forming a laminate from a prepreg laminate is not limited in any way, and may include known methods such as vacuum bag/autoclave curing method, hot press molding method, sheet winding method, sheet wrapping method, tape winding method, tape wrapping method, etc. The following methods can be adopted as appropriate.

Curing conditions such as curing temperature, curing pressure, and curing time are determined by the thermosetting resin used.

For example, when an epoxy resin is used as the thermosetting resin, the general curing temperature is 100 to 250°C, preferably 120 to 200°C. Moreover, pre-cure or post-cure can be performed as appropriate.

The fiber-reinforced resin laminate of the present invention can be easily produced with good reproducibility into products with simple shapes such as plates and pipes, as well as products with three-dimensional shapes of various sizes having curved surfaces or irregularities.

(Example) Examples and comparative examples are shown below. The properties of the interlaminar hybrid laminate on each side were determined for the following specimens at temperature 2
3"C1 Measurements were made 10 times each in the longitudinal direction of the fiber under conditions of 50% relative humidity. Among the above properties, tensile strength, compressive strength, and bending strength were measured using Tensilon UTM manufactured by Orientic.
Measured using 5T, Charpy impact strength is Toyo Seiki ■
The measurements were carried out using a Charpy impact tester manufactured by Kogyo. The bending test is a three-point bending test at span/width=32.

In addition, in the bending test and Charpy impact test, each strength was measured by applying a load to the tyranno layer surface of the laminate.

■Tension test 12.7 200 1.5 2 plates/
Minute compression test 10 60 2 0.5 mm/min bending test 12.7 85 2 2 mm/min Charpy 10 80 2 3.8 m/sec impact test The fiber volume content (Vf) of the laminate is based on ASTM D3171
Measured according to Its unit is volume %.

In the following, all parts are by weight.

Example 1 Bisphenol A epoxy resin (manufactured by Ciba Geigy,
After uniformly mixing 100 parts of XB2879A) and 20 parts of a dicyandiamide curing agent (manufactured by Ciba Geigy, XB2879B), the mixture was dissolved in a mixed solvent of methyl cellosolve and acetone in a weight ratio of 1=1 to obtain 28 parts of the above mixture. Eight cycles of the % heavy weight solution were prepared.

Carbon fiber (manufactured by Toho Rayon, Besphi) HTA60
00: Tensile modulus 24t 7mm”, specific gravity 1°77
) was impregnated with the above solution, wound in one direction using a drum winder, and heated in a hot air circulation oven at 100°C for 14 minutes to prepare a semi-cured unidirectionally aligned carbon fiber prepreg. This prepreg had a resin content of 38% by weight and a thickness of 0.2 mm.

Inorganic fibers consisting of St, Ti, C and 0 (manufactured by Ube Industries, Tyranno fiber: tensile modulus 21t 7mm2, specific gravity 2
．． A unidirectionally aligned tyranno fiber prepreg in a semi-cured state was prepared using 35) in the same manner as above. The resin content of this prepreg was 30% by weight, and the thickness was 0.2 mm.

Using the above two types of prepregs, overlap them in one direction with the configuration shown in Table 1,
By press forming for 250mm x 250mm
A unidirectional interlayer hybrid laminate with a size of mm was produced. Various test pieces were cut out from this laminated material using a diamond saw and subjected to tests. The results are shown in Table 2.

Examples 2 and 3 Example 1 except that the laminated structure was changed as shown in Table 1.
The same method was repeated. The results are shown in Table 2.

Example 4 As carbon fiber, tensile modulus of elasticity 42t/co2, specific gravity 1.8
3 carbon fiber (manufactured by Toho Rayon ■, Besphi) HM4
The same method as in Example 1 was repeated except that 0) was used. The results are shown in Table 2.

Example 5 The same method as in Example 2 was repeated except that the carbon fiber used in Example 4 was used.

The results are shown in Table 2.

Example 6 The same method as in Example 3 was repeated except that the carbon fiber used in Example 4 was used.

The results are shown in Table 2.

Comparative Examples 1 and 2 Example 1 except that the laminated structure was changed as shown in Table 1.
The same method was repeated. The results are shown in Table 2.

Comparative Example 3 Example 1 except that tyranno fiber prepreg was not used
The same method was repeated. The results are shown in Table 2.

Comparative Examples 4 and 5 Example 4 except that the laminated structure was changed as shown in Table 1.
The same method was repeated. The results are shown in Table 2.

Comparative Example 6 Example 4 except that tyranno fiber prepreg was not used
The same method was repeated. The results are shown in Table 2.

Table 1 T ratio Composition = U book product j○1 Example 1 31, TTTTCCCCCC
C” 2 13 TTCCCCCCCC
〃3 6 TCCCCCCCCC”
4 31 TTTTCCCCCC〃5
13 TTCCCCCCC〃6
6 TCCCCCCCCCC Comparative Example 1 31
TCTCCCCTCTN 2 13
TCCCCCCCCTN 3 0
CCCCCCCCCC〃4 31 T
CTCCCCCT// 5 13 T
CCCCCCCCTN 6 0 CC
CCCCCCCC In the structure column of Table 1, T indicates a tyranno fiber layer, and C indicates a carbon fiber layer.

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Claims (1)

[Claims] A fiber-reinforced resin laminate manufactured by laminating prepregs in which carbon fibers and inorganic fibers substantially composed of the elements Si, Ti, or Zr, C, and O are each impregnated with a thermosetting resin, A fiber-reinforced resin laminate, wherein one of the outermost layers of the laminate is composed of the carbon fiber-containing prepreg layer, and the other is composed of the inorganic fiber-containing prepreg layer.