JPH01192841A - Hybrid yarn - Google Patents

Abstract

PURPOSE:To obtain a hybrid yarn suitable for the production of a laminated board having improved flexural properties, by mixing carbon fiber with a specific inorganic fiber while widening the width of each fiber bundle. CONSTITUTION:Carbon fibers are blended with inorganic fibers essentially composed of the elements of Si, Ti or Zr, C and O while widening the width of each fiber bundle. The widening of the fiber is carried out by passing through a comb-like slit, passing through a number of tension rollers, applying mechanical vibration to the fiber, passing through a fluid such as water, etc. The inorganic fiber is produced by reacting a polycarbosilane having a number-average molecular weight of about 200-10,000 and expressed by formula I (R is H, lower alkyl or phenyl) with a metal compound of formula II (M is Ti or Zr; X is 1-10C alkoxy, phenoxy or acetylacetoxy), spinning the reaction product and infusibilizing and calcining the obtained fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hybrid yarn in which carbon fibers and specific inorganic fibers are mixed.

(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.

For this reason, attempts have been made to solve the above problems by using so-called hybrid composite materials that combine carbon fibers and other fibers. Conventionally, glass fibers and aramid fibers have been preferably used as fibers to be combined with carbon fibers. However, glass fibers have a problem of low strength and elastic modulus and are also heavy, and 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
It is obtained by laminating prepreg impregnated with plastics on a hybrid yarn in which inorganic fibers and carbon fibers composed of the elements , C, and ○ are mixed in one layer, and then pressurizing and heating this laminate. Composites, so-called intralaminar hybrid composites, are 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 glabella shear strength and Charpy impact strength.

In recent years, inorganic fiber-reinforced plastic composite materials are required to have high bending strength and compressive strength in addition to the above-mentioned excellent strength. From this point of view, the composite material described in the above publication has room for improvement in bending strength, as shown in the Examples of the publication.

(Objective of the Invention) The object of the present invention is to create a laminate material that maintains the advantages of the intralayer hybrid laminate material described in JP-A-62-7737 while improving its bending properties, which is its biggest problem. Our goal is to provide hybrid yarns needed for manufacturing.

(Technical means for solving the problem) According to the present invention, carbon fibers and inorganic fibers substantially composed of the elements Si, Ti, Zr, C, and O are widened in the longitudinal direction. A viblint yarn is provided which is a hybrid yarn obtained by blending fibers, and in which the tensile modulus of the inorganic fibers is within the range of 0.6 to 1.4 relative to the tensile modulus of the carbon fibers.

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 tensile modulus of carbon fiber varies depending on the type of precursor, firing temperature, etc., but -J'G has a tensile modulus of 1 for carbon fiber.
5-30 t/+m++2, 30-5 for graphite fibers
0t/2 cylinders.

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 having a number average molecular weight of about 200 to 10,000 and having a main chain skeleton represented by the formula R 1+Si CHz→- (wherein R represents a hydrogen atom, a lower alkyl group, or a phenyl group), and a polycarbosilane having a number average molecular weight of about 200 to 10,000 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), the total number of (Si-CHz) structural units of the polycarbosilane versus the total number of (Si-CHz) structural units of the organometallic compound of the total number of structural units is within the range of 2:1 to 200:1, and heated in an atmosphere inert to the reaction 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 about 700 to 100,000, and a spinning dope 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, and 0: 0.01-30% by weight.

Generally, the tensile modulus of the above inorganic fibers is 20 to 25 t/mm.
It is within the range of 2.

What is important in the present invention is the relative value of the tensile modulus of carbon fiber and inorganic fiber.

That is, the ratio of the tensile modulus of the inorganic fiber to the tensile modulus of the carbon fiber used is 0.6 to 1.4, preferably 0.6 to 1.4.
Must be within the range of 8 to 1.2. If the ratio of the elastic modulus of both fibers is out of the above range, in-plane fracture is likely to occur in the intralayer hybrid laminate made using these fibers due to the difference in tensile modulus, and as a result,
In-plane strengths such as tensile strength and compressive strength are reduced, and the effect of improving bending properties is also reduced. Therefore, in the present invention, it is extremely important to select inorganic fibers and carbon fibers so that the ratio of tensile modulus falls within the above range.

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 ratio is less than 1% by volume, the effect of improving the bending strength of the laminated material is small, and if it is greater than 80% by volume, the ratio of carbon fiber is relatively reduced, and the high tensile strength and lightweight properties of carbon fiber are added to the laminated material. becomes difficult to grant.

As will be described later, the hybrid yarn of the present invention is obtained by mixing both fibers while widening them, so it is preferable that both fibers have very little twist, particularly non-twist. Both fibers may be subjected to known surface treatments and sizing treatments.

The above-mentioned hybrid yarn is generally obtained by mixing inorganic fibers and carbon fibers while expanding the width in the longitudinal direction. All methods known per se can be used to mix the fibers, including a method of passing the fibers through comb-shaped slits provided in the longitudinal direction, a method of passing the fibers through a number of tension rollers, and a method of mechanical A method of imparting vibration,
Examples include a method of passing through a fluid such as water, and a method of using these methods in combination.

The resulting high print yarn is generally bundled with a binding agent. As the sizing agent, known substances such as epoxy resin, polymethyl methacrylate, polyvinyl alcohol, and polyethylene oxide can be used.

These sizing agents are generally used as aqueous solutions or emulsions. The amount of the sizing agent deposited is usually 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight, per 100 parts by weight of the hybrid yarn. The number of filaments constituting the resulting hybrid yarn is usually 1000 to 200.
00 pieces, preferably 3000 to 10000 pieces.

The hybrid yarn of the present invention can be used to prepare a unidirectional prepreg from which a laminate can be manufactured.

There are no particular restrictions on the method for producing a unidirectional hybrid v-doped prepreg from a hybrid yarn, and any known method can be employed.

Examples include a method in which hybrid yarns bundled with a sizing agent are impregnated with a thermosetting resin and aligned in one direction, and a method in which unbound hybrid yarns are directly impregnated with a thermosetting resin and aligned in one direction. can be mentioned.

There are no particular limitations on the thermosetting resin, and examples thereof include epoxy resins, unsaturated polyester resins, vinyl ester resins, phenol resins, bismaleimide resins, and polyimide resins. 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 polyepoxide include bisphenol A,
Examples include glycidyl compounds of F and S, glycidyl compounds of cresol 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, glycidyl ether of bisphenol A, glycidyl compounds of cresol novolak or phenol novolak, glycidyl compounds of diaminodiphenylmethane, and glycidyl compounds of aminophenol are generally used. Further, when the laminate is used as a member requiring high functionality such as a primary structural material of an aircraft, it is preferable to use a glycidyl compound of a polyfunctional amine such as diaminodiphenylmethane among the above polyepoxides.

The total proportion of carbon fibers and inorganic fibers to the prepreg is usually 30 to 80% by volume, preferably 45 to 65% by volume.
It is. That is, the proportion of thermosetting resin in the prepreg is 20 to 70% by volume, preferably 35 to 55% by volume.

Prepreg can be prepared by pulling a large number of hybrid yarns in one direction and sandwiching them between thermosetting resins to form prepregs, or by winding a bundle of hybrid yarns impregnated with thermosetting resin around a drum to form prepregs. Methods known per se can be appropriately employed, such as a method of preparing a prepreg by aligning a large number of hybrid yarns and then melting and impregnating a film-like material of a thermosetting resin.

The thickness of the unidirectional hybrid prepreg thus obtained can vary widely from 10 to 300 μm, but for boat fishing it is 50 to 200 μm. In addition, the proportion of volatile components contained in the hybrid prepreg is 1% by weight.
It is desirable that it be within

The laminated material is manufactured by laminating a plurality of the above unidirectional hybrid prepregs and then curing the thermosetting resin.

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.

The lamination form may be any of the commonly practiced symmetrical lamination, asymmetrical lamination, reverse symmetrical lamination, etc.

Further, there is no particular restriction on the lamination order, and any repeating thickness can be used.

The method for forming a laminate from a prepreg laminate is not limited in any way, and may include vacuum hack/autoclave curing, hot press molding, sheet winding, sheet rashing, tape winding, tape wrapping, etc. Any known method can be appropriately employed.

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 laminated material thus obtained can be easily produced into products with simple shapes such as plates and pipes, as well as three-dimensional products of various sizes with curved surfaces or irregularities with good reproducibility.

(Example) Examples and comparative examples are shown below. The physical properties of the intralaminar hybrid laminates on each side were determined using a Tensilon UTM5T manufactured by Orientic Co., Ltd. at a temperature of 23° C. for the following test specimens.
1 each along the length of the fiber under conditions of 50% relative humidity at °C1.
Measured 0 times. The bending test is a three point bending test at span/width -32.

■Tension test 12.7 200 1.5 2 Compression test 10 60 2 0.5 Bending test 12.7 85 2 2 The fiber volume content (Vf) of the laminate was measured according to ASTM D3171. Its unit is volume %.

In the following, all parts are by weight.

Example 1 Carbon fiber yarn (manufactured by Toho Rayon ■, Besphite HT
A6000: diameter 7 μm, specific gravity 1.77, tensile modulus 2
4t/mm2.6000 filament) 1 piece and Sl,
Inorganic fiber yarn consisting of TiC and 0 (manufactured by Ube Industries, Ltd.)
Tyranno fiber: diameter 8.5 μm, specific gravity 2.35, tensile modulus 21 t/pus 2.800 filament) Each piece of wood was passed through a pipe through which water was flowing and then led to an aquarium. Next, each yarn was widened while applying mechanical vibration, and the yarns were mixed so that they were in contact with each other.

A hybrid yarn was obtained by passing the mixed yarn through an epoxy emulsion bath with a concentration of 2% by weight, followed by drying and bundling. The amount of the sizing agent attached was 1 part per 100 parts of fibers.

When the obtained hybrid yarn was observed with a scanning electron microscope, it was found that carbon fiber fin laments and inorganic fiber filaments were uniformly mixed.

Example 2 Bisphenol A epoxy resin (manufactured by Chiha Geigy,
After uniformly mixing 100 parts of X, B2879A) and 20 parts of a dicyandiamide curing agent (manufactured by Ciba Geigy, XB2B79B), the mixture was dissolved in a mixed solvent of methyl cellosolve and acetone in a weight ratio of 1=1 to obtain the above mixture. A 28% by weight solution was prepared.

After impregnating the hybrid yarn obtained in Example 1 with this solution, it was rolled up in one direction using a drum wine gourd and heated in a hot air circulation oven at 100°C for 14 minutes to bring it to a semi-cured state. A directionally aligned hybrid prepreg was prepared. This prepreg had a resin content of 30% by weight and a thickness of 0.2 mm.

When the obtained prepreg was observed with a scanning electron microscope, it was observed that carbon fibers and inorganic fibers were uniformly distributed and arranged in the resin.

Example 3 A unidirectional intra-layer hybrid laminate with a size of 250 mm x 2'50 body was produced by stacking the prepregs obtained in Example 2 in one direction and press-molding them at 130°C1l1kg/effl for 90 minutes. Manufactured. Various test pieces were cut out from this laminated material using a diamond saw and subjected to tests. The results are shown in Table 1. Table 1 also shows the ratio of inorganic fibers to total fibers.

Example 4 The same method as in Example 1 was repeated except that the number of inorganic fiber filaments was changed to 1600.

The obtained hybrid yarn also had a uniform mixture of carbon fiber filaments and inorganic fiber filaments.

Example 5 A unidirectional hybrid prepreg was obtained by repeating the same method as in Example 2, except that the hybrid yarn obtained in Example 4 was used as the hybrid yarn. The fiber content of this prepreg was 30 weight and the thickness was 0.2 mm. Carbon fibers and inorganic fibers were uniformly distributed within the prepreg.

Example 6 An intralayer hybrid laminate material was obtained by repeating the same method as in Example 3 except that the prepreg obtained in Example 5 was used as the prepreg. Table 1 shows the physical properties of this laminate.

Comparative Example 1 The same method as in Example 6 was repeated except that carbon fiber having a diameter of 6.6 μm, a specific gravity of 1.83, a tensile modulus of 42 t 7 mm 2 and a number of filaments of 6000 was used as the carbon fiber. Table 1 shows the physical properties of the obtained laminate.

Comparative Example 2 The same method as Example 3 was repeated except that no inorganic fibers were used. Procedural amendment (voluntary) for the physical properties of the obtained laminated material April 2b, 1989

Claims (1)

[Claims] A hybrid yarn obtained by mixing carbon fibers with inorganic fibers substantially composed of Si, Ti, or each element of Zr, C, and O while expanding the width in the longitudinal direction, and the tensile modulus of the carbon fibers is A hybrid yarn characterized in that the tensile modulus of the inorganic fibers is within the range of 0.6 to 1.4.