JPH036241A - High-strength high-modulus hybrid prepreg - Google Patents

Abstract

PURPOSE:To prepare a hybrid prepreg having the maximum compression strength with the minimum loss in the modulus by making the prepreg to contain a carbon fiber filament and a specified amt. of another fiber filament and impregnating with a matrix resin. CONSTITUTION:A hybrid prepreg comprising a carbon fiber filament and at least one other fiber filament (e.g. silicon carbide fiber, alumina fiber, or glass fiber) and impregnated with a matrix resin (e.g. epoxy resin or phenol resin) is prepd. Said other fiber filament is contained in such an amt. that the hybrid prepreg. has a modulus of at lest 80% of that of a prepreg comprising said carbon fiber filament alone. The obtd. hybrid prepreg is given the maximum compression strength with the minimum loss in the modulus.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hybrid type composite material, and in particular to a hybrid type carbon fiber prepreg formed of carbon fiber yarns and different types of fiber yarns (hereinafter referred to as In the book, it is simply called "hybrid prepreg").

In recent years, prepregs reinforced with 5 carbon fibers have become popular because they are lightweight, have excellent environmental resistance such as heat resistance and water resistance, and have good mechanical properties. It is attracting attention.

However, high modulus carbon fiber, especially pitch-based height n+
T4e elementary fibers have a tensile strength of 1, for example, 3,0 GPa or more.
H. High tensile strength with a tensile modulus of 450 GPa or more 1. Although it has a high tensile modulus, it has a problem in that its compressive strength is low, at most about 1 + 0 GPa.

Therefore, carbon fiber prepregs produced using high modulus carbon fibers as reinforcing fibers have low compressive strength compared to their tensile strength and tensile modulus, and it is desired to increase the compressive strength.

In the past, hybrid prepregs containing carbon fibers and different types of fibers have been proposed to increase compressive strength.
Currently, hybrid and Doburi Preg are produced by interlayer hybrids formed by planting a layer of carbon fiber and a layer of different types of fibers, and by placing a region of carbon ka fibers and a region of different types of fibers adjacent to each other within one layer. It is thought to be an intralayer hybrid formed by

This kind of hybrid prepreg can be made using 1kl of ordinary charcoal.
Although the compressive strength has increased considerably compared to the A fiber prepreg, there is considerable variation in the actual strength of the #a fibers, and because the fibers are cut in order starting from the weakest fibers, the degree of increase is less than that of the hybrid composite fj11. In accordance with the above, the hybrid rule was not exceeded, and it could not be said that it was still sufficient.

Furthermore, the present inventors have conducted numerous studies and experiments, and have found that, unlike the conventional hybrid prepreg, for example, when a prepreg is produced by uniformly dispersing carbon M&fiber threads and different types of fiber threads. It has been found that by increasing the contact area between carbon fiber yarn and different type of fiber yarn, the compressive strength of the hybrid composite can be increased to an extent that exceeds the hybrid rule.

Furthermore, we continued to study the relationship between physical property values and the mixing of carbon fiber yarns and different types of fiber yarns in such hybrid prepregs, and found that (1) increasing the mixing of different types of fiber yarns; Accordingly, the compressive strength] increases, but the elastic modulus decreases. 1. Importantly, (2) mixing of different types of fiber yarns increases the combination, and the elastic modulus decreases. It was found that even if the modulus of elasticity exceeds 20% of the elastic modulus of carbon fiber prepreg made only of carbon fibers, a proportional increase in compressive strength cannot be expected.

The present invention has been made based on this new knowledge.

Therefore, an object of the present invention is to provide a high-strength, high-modulus hybrid prepreg that can obtain maximum compressive strength with a minimum reduction in adhesiveness.

The above objects are achieved by the high strength, high modulus hybrid prepreg according to the present invention. In summary, the present invention provides a hybrid prepreg comprising a carbon fiber thread and one or more types of different types of fiber threads, and a matrix resin is impregnated between the fiber threads, wherein is a high-strength, high-modulus hybrid prepreg characterized in that the elastic modulus of the hybrid prepreg is 80% or more of the elastic modulus of the carbon fiber prepreg made only of carbon fiber yarns. It is.

1. Next, the high-strength, high-modulus hybrid prepreg according to the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows an embodiment of the high strength, high modulus hybrid prepreg of the present invention.
The high elastic modulus hybrid prepreg 1 has carbon M & fiber threads 2 and dissimilar fiber threads 4 of type 1 layer-H arranged in a uniformly dispersed manner, and matrix resin 6 is impregnated between the fiber threads. configured.

As the carbon fiber yarn 2, pitch-based carbon fibers, PAN-based carbon fibers, and Yong-based carbon fibers can be used, but preferably have a tensile strength of 2.0 GPa or more and a modulus of elasticity of 20.
Carbon and R fibers with high tensile strength and high tensile modulus of 0 GPa or higher are used.

In addition, the carbon fiber yarn generally has a diameter of 5 to 1277 mm.
A carbon fiber strand (tow) formed by gathering and plying 1,000 to 24,000 7<m laments of about 7 mm is used.

As the dissimilar fiber yarn 4, any fiber can be used as long as it has a higher compressive strength than carbon fiber, such as silicon carbide fiber, alumina fiber, titanium, steel, stainless steel, beryllium, tungsten, molybdenum. Examples include metal fibers such as; boron fibers; and glass fibers. Preferably, fibers with a compressive strength of 1.5 GPa or more are used, and the fiber threads generally have a diameter of 5 to 5.
A strand is used which is formed by gathering and plying 1000 to 240 OO filaments with a diameter of about 12 m.

The matrix resin 6 impregnated into the reinforcing fibers consisting of carbon fiber threads and different types of M and male threads in 11h is a thermosetting matrix resin such as epoxy resin, unsaturated polyester resin, polyurethane resin, diallyl phthalate resin, or phenol resin. The hitting surface is used, and the curing temperature is 50~
A curing agent and other imparting agents (for example, a) property imparting agent are appropriately added so that the temperature is 150°C.

To give a trivial example, epoxy resins are preferred as matrix resins, and examples of usable epoxy resins include (1) glycidyl ether epoxy resins (
(2) Cycloaliphatic epoxy resin; (3) Glycidyl ester epoxy resin: (4) Glycidyl amine epoxy Resin; (5) Heterocyclic epoxy resin: One or more selected from various epoxy resins are used, and bisphenol AF and S-glycidylamine-based epoxy resins are particularly preferably used. In addition, diaminodiphenylsulfone (DDS) is used as a curing agent.
, diaminodiphenylmethane (DDM), etc. are preferably used.

Manufactured by adjusting the weight of standard matrix resin to reinforcing fibers to 100 to 150 parts per 100 parts of reinforcing fibers, or by mixing various matrix resins and appropriately blending 51 parts of them. .

Further, such a hybrid prepreg can be manufactured by the same method as a normal carbon fiber prepreg, but to explain it simply, it is made by using a long fiber carbon fiber yarn 2 and a single layer of different types and layers.
A reinforcing fibers made by uniformly dispersing fiber threads 4 are continuously supplied, and the viscosity is tooooo to 5000.
A thermosetting matrix resin of 00 poise is supplied to the reinforcing fibers, and the reinforcing fibers are impregnated with pressure and heat using a roll or the like to a predetermined thickness (usually 0.05 to 0.3 mm). It is manufactured by sandwiching the cured state (ie, soft state) between a resin-coated paper and an upper cover film and winding it up on a take-up roll.

In addition, as an alternative method, long M & male carbon m miscellaneous threads and 1
It is produced by winding reinforcing fibers made by uniformly dispersing more than one type of #a fiber thread. The so-called
It can also be produced by drum winding.

FIG. 2 shows that in the no-brid prepreg 1 having the above structure, many /\ hybrid prepregs are produced by changing the mixing ratio of the carbon fiber yarn 2 and the different kind of fiber yarn 4, and each /λ hybrid prepreg is The results of measuring the elastic modulus and compressive strength are shown. As the mixing ratio of the different fiber yarn 4 to the carbon fiber yarn 2 increases, the elastic modulus decreases.

From FIG. 2, it can be seen that the decrease in the elastic modulus of the hybrid prepreg caused by increasing the mixture of different fiber yarns is 20% or less of the elastic modulus of the carbon fiber prepreg made only of carbon fibers used. In some cases, the compressive strength of the hybrid prepreg increases dramatically, but when the rate of decrease in the elastic modulus exceeds 20%, the rate of increase in the compressive strength of the hybrid prepreg decreases rapidly, and even though the elastic modulus decreases, It is understood that an increase in compressive strength cannot be expected.

In other words, in order to obtain a high-strength, high-modulus hybrid prepreg, the inclusion of different types of fiber threads in the hybrid prepreg is such that the elastic modulus of the hybrid prepreg is 80% of the elastic modulus of the carbon fiber prepreg made only of carbon fiber threads.
% or more is Me.

Further, according to the present invention, the physical properties and mixing ratio of the carbon fibers and different types of fibers used, as well as the matrix tree 11''L1
By changing the impregnation ratio of the matrix resin and by varying the composition ratio of the matrix resin used, Hyply 7 Dobbly preg that provides various compressive strengths, tensile strengths, tensile modulus, and even toughness can be produced. .

Furthermore, the high-strength, high-modulus hybrid prepreg according to the present invention is not limited to the hybrid prepreg 1 having the configuration shown in FIG. 1, but also the hybrid prepreg 1 having the configuration shown in FIGS. Prepregs la to 1d may also be used.

That is, in the hybrid prepreg la shown in FIG. 3, the carbon m fiber threads 2 and the different types of #a fiber threads 4 are arranged in a layered manner within one layer. Hybrid prepreg lb in Figure 4
In one layer, carbon fiber yarn 2 and dissimilar fiber yarn 4
The layered bodies in which are alternately arranged are arranged in yi layers. In the lλ hybrid prepreg 1c shown in FIG. 5, a layer consisting of carbon fiber threads 2 and a layer in which carbon fiber threads 2 and different types of fiber threads 4 are arranged alternately are arranged in a layered manner. has been done. The hybrid prepreg 1d in FIG.
In one layer, carbon fiber threads 2 and dissimilar fiber threads 4 are arranged in a layered manner, and both threads 2.4 are in contact with each other at an inclined joining surface.

FIGS. 7 and 8 show hybrid composites of a hybrid prepreg made of carbon edge m/silicon carbide This is a graph representing

Referring to FIG. 7, the strength of carbon fiber is shown by line AB, and the strength of silicon carbide X-based fiber is shown by line CD. Therefore, the hybrid line is line A.
It is represented by ED.

It was impossible to achieve strength higher than the hybrid line with conventional carbon fiber/silicon carbide was able to increase until it was located in the shaded area surrounded by line AED.

The same was true for the hybrid composite of carbon fiber/alumina fiber hybrid prepreg shown in FIG.

Next, the present invention will be explained with reference to examples.

Diameter 10 as a bright Ou carbon Mll filament. A strand (tow) of 3000 um monofilaments was used. The carbon fiber had a tensile strength of 3°0 GPa and a tensile modulus of 700 GPa.

Furthermore, as the different type of fiber yarn, silicon carbide X-based fiber (manufactured by Kuchiki Carbon Co., Ltd., trade name: Nicalon, NL201) was used. The silicon carbide

The carbon fiber threads and the silicon carbide

The reinforcing fibers were wrapped around the surface of a drum wine goo coated with a matrix resin prepared as described above.

The matrix resin is bisphenol A-based epoxy resin EP828 (trade name) manufactured by Yuka Shell Epoxy Co., Ltd.
50gr 150gr of EPLOOI (trade name), dicyandiamide 4,2gr as curing agent, DCM
It contained 4.2 gr of U (N-3,4 dichlorophenylene N'-dimethylurea).

In this way, the thickness is 0. ．． A 1 mm one-sided hybrid prepreg was produced. At this time, the amount of reinforcing fiber with respect to Madris resin, that is, the impregnation rate, was such that the resin/fiber volume ratio was 40/60.

Using 20 sheets of the hybrid prepreg, 2oPf:
Composition of 12.7 (IllIJ) Xl, 89 (thickness) x
A test piece T for bending test having a length of 140 mm was prepared.

In the test, as shown in FIG. 9, the test piece T was placed at two locations 8. The test piece was supported by lO and a load P was applied from two locations in the center to bend the test piece. If an initial break occurs on the tension side of the test piece, the tensile strength can be estimated, and if an initial break occurs on the compression side, the compressive strength can be estimated. The compressive strength was evaluated by the bending strength at the point where a crack appeared on the compression side of the test piece and the stress decreased. In addition, the elastic modulus was determined by calculation.

As a result of the test, the initial fracture occurred on the compression side, and the final fracture occurred on the tension side, but it did not break into 5 parts.

The maximum compression side fracture rJ weight was 44 Kg, the bending strength at this time was 78 K g/mm', and the strain was 0.
It was 51.

Also, the elastic modulus was 30 ton/mm', and the decrease in the elastic modulus in this example was 18%, as can be understood by comparing with Comparative Example 2 described later. It can be seen that the hybrid prepreg has a strength (point X) higher than the hybrid rule (line ED).

A hybrid prepreg was produced using the same materials and method as in Example 1, except that the mixing ratio of carbon M & fiber strips and silicon carbide thread fibers was 57/43 by volume, and the test was carried out in the same manner. I did it.

As a result of the test, a crack appeared on the tension side under a load of 165 kg, but it did not break. The bending strength at this time is l l
5. K g/mm'te, and the strain was 1.96.

Further, the elastic modulus was 25 ton/mrn', and the decrease in the elastic modulus in this comparative example was 29%, as will be understood when compared with Comparative Example 2, which will be described later.

"Saramonsho" Monofilament 30 with a diameter of 10.4m as reinforcing fiber
A carbon fiber prepreg was produced in the same manner as in Example 1, except that only carbon am strands (tow) made of 00 carbon fibers were used, and tests were conducted in the same manner.

As a result of the test, a crack appeared on the compression side at a load of 46 kg and the product was separated. The bending strength at this time is 74 Kg/
m rn', and the strain was 0.21.

Therefore, the elastic modulus was 35*on/mm.

As a different type of fiber thread, the diameter is 15mm. A hybrid prepreg was produced in the same manner as in Example 1, except that alumina fiber (manufactured by Sumitomo Chemical Co., Ltd., trade name: 5N-10) made by splicing 1000 un monofilament wood was used, and a test was carried out in the same manner. I did it.

The test results showed that the initial failure occurred on the compression side and the final failure occurred on the tension side, but did not separate.

The maximum compression side breaking load was 41 Kg, the bending strength at this time was 77 Kg/mTrl', and the strain was 0.52.

Further, the elastic modulus was 32 ton/mrn', and the decrease in the elastic modulus in this example was 18%, as understood when compared with Comparative Example 2 above.

From FIG. 8, it can be seen that the hybrid prepreg of the present invention has a strength (point X) that is higher than the hybrid rule (line ED).

"L Gloss L" The mixing ratio of carbon fiber yarn and alumina fiber is 57% by volume.
A hybrid prepreg was produced using the same materials and method as in Example 2, except that /43 and 17 were used, and the test was conducted in the same manner.

As a result of the test, a crack appeared on the tensile side when the load was 156 kg, but it did not break into two parts. The bending strength at this time is l O
There was 5K g/mrn'te, and the strain was 1.82.

Further, the elastic modulus was 25 ton/mrn', and the decrease in the elastic modulus in this comparative example was 23%, as understood when compared with Comparative Example 2 above.

From the above Examples and Comparative Examples, (1) as the proportion of mixed #a miscellaneous yarns increases, the compressive strength increases but the modulus of elasticity decreases.

(2) Even if the elastic modulus decreases by more than 20% of the elastic modulus of carbon fiber prepreg made only of carbon fibers by increasing the mixing ratio of different types of fiber yarns, the compressive strength will increase proportionally. I realized that I couldn't expect anything.

The high-strength, high-elastic modulus hybrid prepreg according to the present invention, which is constructed as above as above, has a minimal reduction in bone modulus,
It has the feature of being able to obtain maximum compressive strength.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an embodiment of a hybrid prepreg according to the present invention. FIG. 2 is a graph showing the relationship between the rate of decrease in elastic modulus and the rate of increase in compressive strength. 3 to 6 are schematic cross-sectional views of other embodiments of the hybrid prepreg according to the present invention. FIG. 7 and FIG. 8 are graphs illustrating the hybrid composite agent of the hybrid prepreg according to the present invention. FIG. 9 is an explanatory diagram illustrating the test method. 2: Carbon fiber thread 4: Different type of fiber thread Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 2 Fig. 2 10 20 30 40 50 mm2 Nikalon VoL ratio (%)

Claims (1)

[Claims] 1) A hybrid prepreg comprising carbon fiber threads and one or more types of different types of fiber threads, the fiber threads being impregnated with a matrix resin, wherein the different types of fiber threads have an elastic modulus of the hybrid prepreg. A high-strength, high-modulus hybrid prepreg characterized in that the carbon fiber prepreg comprising only carbon fiber threads has an elastic modulus of 80% or more of that of the carbon fiber prepreg.