JPH0353334B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a core wire comprising an inner layer and a surface layer, and is made of richly colored inorganic fibers, carbon fibers, glass fibers, boron fibers, aramid fibers, and carbon. The present invention relates to a composite material having beautiful mechanical properties and color tone, which is reinforced with a hybrid fiber of at least one type of fiber selected from the group consisting of silicon carbide fiber and silicon carbide fiber.

(Prior Art and its Problems) As a conventional reinforcing material, research is underway on hybrid fiber-reinforced composites in which two or more types of fibers are placed in a matrix in order to utilize the characteristics of various materials.

Research has been conducted on the above hybrid fibers, such as carbon/glass, carbon/aramid fiber, boron/carbon, boron/aramid fiber, boron/glass, ceramic fiber/aramid fiber, aramid fiber/glass, etc. , carbon/aramid fibers are overwhelmingly common, and actual applications are almost limited to these two types.

Conventional hybrid fibers are all achromatic in color, ranging from white to black, so composites reinforced with these fibers have poor color, and the surface of the composite must be coated or coated with other resins. It was not possible to obtain composites with a beautiful appearance and various color tones unless they were laminated.

Metals or plastics reinforced with inorganic fibers can be used in products that require strength and lightness, such as
It is used in a wide range of products ranging from tennis rackets, fishing rods, ski stocks, ski wedges, racing car pipes, etc. to aircraft and automobiles. For these uses, not only mechanical strength but also beautiful appearance and fashionability are required as important factors. Conventionally known pipe-lid fibers cannot satisfy the two requirements of sufficient mechanical strength and beautiful appearance at the same time.

(Objective of the Invention) An object of the present invention is to provide a hybrid fiber-reinforced composite having a beautiful color tone and excellent mechanical properties.

(Summary of the Invention) According to the present invention, a hybrid fiber of an inorganic fiber and at least one type of fiber selected from the group consisting of carbon fiber, glass fiber, boron fiber, aramid fiber, and silicon carbide fiber having a carbon core. In a hybrid fiber-reinforced composite with a plastic or metal matrix as a reinforcing material,
The inorganic fibers are () an amorphous substance consisting essentially of Si, C and O, or () crystalline ultrafine particles and amorphous SiO ₂ consisting essentially of β-SiC with a particle size of 500 Å or less. or () a mixed system of the amorphous material of the above () and the crystalline ultrafine particle aggregate of the above (); , () an amorphous substance consisting essentially of Si and O, () an aggregate consisting of amorphous SiO ₂ , or () a combination of the above () amorphous substance and the above () crystalline polymer. A hybrid fiber-reinforced composite is provided, characterized in that it comprises a surface layer of an inorganic material containing a mixed system of silicon and oxygen, optionally containing up to 5% by weight of carbon.

(Detailed Description of the Invention) In the present invention, the inner layer that occupies most of the inorganic fibers that are the constituent components of the hybrid fiber is () an amorphous material consisting essentially of Si, C, and O, or () particle size. an aggregate consisting of crystalline ultrafine particles substantially made of β-SiC with a diameter of 500 Å or less and amorphous SiO ₂ , or () the amorphous substance described in () above and the crystalline ultrafine particles described in () above A mixed system of aggregates, consisting of an inorganic substance containing silicon, carbon and oxygen.

In addition, the surface layer of the inorganic fibers may be () an amorphous substance consisting essentially of Si and O, () an aggregate consisting of crystalline SiO ₂ , or () the amorphous substance of () above and the above. It consists of an inorganic material containing silicon and oxygen, and optionally 5% by weight or less of carbon, consisting of a mixed system of crystalline polymers ().

The above-mentioned inorganic fiber can be obtained, for example, by first preparing a precursor inorganic fiber having the same composition as the inner layer, and then heating this fiber in an oxidizing atmosphere to form a surface layer.

A precursor inorganic fiber having the same composition as the inner layer can be prepared, for example, according to the method described below.

A first step of heating a polysilane having at least one alkyl group in a side chain in the presence or absence of a catalyst to produce a polycarbosilane;
a second step of preparing and spinning a spinning dope of the polycarbosilane; a third step of infusibleizing the spun fiber under tension or no tension; and a step of infusibilizing the spun fiber in a vacuum or an inert gas atmosphere. 800～
From the fourth step of firing at a temperature in the range of 1800° C., a precursor inorganic fiber consisting essentially of Si, C and O can be produced.

The proportion of each element in the precursor inorganic fiber is usually Si: 30-60% by weight, C: 25-40% by weight, O: 0.01-30% by weight It is.

The precursor inorganic fiber obtained in this way is usually 500~
By heating in an oxidizing atmosphere at a temperature in the range of 1600°C, a surface layer is formed and the inorganic fiber of the present invention is obtained. Examples of the oxidizing atmosphere include atmospheres such as air, pure oxygen, ozone, water vapor, and carbon dioxide gas.

This treatment imparts various colors to the inorganic fibers, such as red, purple, blue, green, orange, brown, and peach. The color tone of the inorganic fiber can be arbitrarily changed by changing the heating conditions in an oxidizing atmosphere and adjusting the thickness and structure of the surface layer. For example, when the oxidation conditions are mild, the color becomes red or purple, and as the oxidation conditions are made more severe, the color becomes blue or green. A person skilled in the art can easily adjust the color tone according to the above indication.

The proportions of each element in the inner layer of the inorganic fiber thus obtained are substantially the same as above, and the proportions of each element in the surface layer are usually Si: 40-65% by weight, O: 30-55% by weight, C: It is 0 to 5% by weight.

The diameter of the inner layer of inorganic fibers in the present invention is usually 2 to 20 μm, and the thickness of the surface layer is usually 0.01 to 5 μm.
It is m.

These inorganic fibers can be used by uniaxially or multiaxially orienting the fibers themselves, or by making various patterned fabrics such as plain weave, satin weave, patterned weave, twill weave, leno weave, spiral weave, and three-dimensional weave. , or as a chopped strand fiber.

The proportion of inorganic fibers in the hybrid fiber is preferably 10% or more, particularly 20% or more. If the proportion of inorganic fibers is too small, the effects of improving mechanical properties, which are the objectives of the present invention, such as improving the bond strength between the inorganic fibers and the matrix, improving reinforcing efficiency, and reducing the fatigue strength reduction rate, will be insufficient. .

Looking at the hybrid state of hybrid fibers by form, there are (1) interlayer hybrids in which a layer of one type of fiber and a layer of another type of fiber are laminated, and (2) intralayer hybrids that have already been hybridized within one layer. There are basically two types of hybrids, and (3) there are also combinations of them.
There are six main types of combinations:

(a) Laminated single-layer tape (layers of different fibers are alternately layered) (b) Sandwich type (layers of different fibers are layered in a sandwich) (c) Rib reinforcement (d) Blended tow (Hybrid of different fibers in each single fiber unit) (e) Lamination of mixed tape (Hybrid of different fibers in each yarn unit) (f) Mixed surface layer Next, in the present invention, the matrix Examples of metals constituting the metal include aluminum, magnesium, titanium, and alloys thereof.

Examples of plastic matrices include epoxy resin, modified epoxy resin, polyester resin, polyimide resin, phenolic resin, polyurethane resin, polyamide resin, polycarbonate resin, silicone resin, phenoxy resin, polyphenylene sulfide resin, fluorine resin, Hydrocarbon resin, halogen-containing resin, acrylic acid resin, ABS
Examples include resin, ultra-high molecular weight polyethylene, modified polyphenylene oxide, and polystyrene.

There are no particular limitations on the method for producing the hybrid fiber-reinforced composite of the present invention, and the composite can be produced by methods known per se.

The metal composite is manufactured according to known methods for manufacturing metal composite materials, such as diffusion bonding, liquid infiltration, thermal spraying, electrodeposition, extrusion and hot rolling, chemical vapor deposition, or sintering. can do.

Methods for producing plastic composites include methods known per se, such as a hand lay-up method, a mated metal die method, a breakaway method, a filament winding method, a hot press method, an autoclave method, and a continuous drawing method.

The proportion of hybrid fibers in the reinforced composite of the invention is preferably 10 to 70% by volume, based on the composite. Even if the proportion of hybrid fibers is excessively high, the amount of matrix will be relatively small, and the gaps between the reinforcing fibers will not be able to be filled sufficiently with the matrix, and the strength according to the law of compounding will not be exhibited. It disappears. Furthermore, if the proportion of hybrid fibers is too low, it becomes difficult to obtain a composite with good mechanical properties.

In the present invention, the distribution of the hybrid fibers in the composite is controlled by attaching a dispersing material such as powder of a heat-resistant substance, short fibers, or whiskers to each fiber constituting the hybrid fibers or to the hybrid fibers themselves. It can be made uniform.

There are no particular restrictions on the method for depositing the above-mentioned dispersion material, and for example, electrodeposition, a method using a fluidized bed, a spraying method, a suspension dipping method, etc. can be employed. The suspension dipping method can be suitably employed from the viewpoints of simplicity and wide applicability.

An example of the suspension dipping method is to unwind inorganic fibers wound around a bobbin or a continuous inorganic fiber bundle made by bundling an appropriate number of inorganic fibers, or to immerse a woven inorganic fiber in a liquid in which a dispersant is suspended. An example is a method in which a dispersing material is attached to the surface of each of the inorganic fibers or the fibers of the textile. When immersing an inorganic fiber bundle or fabric with a large number of fibers, it is preferable to apply vibration using ultrasonic waves to uniformly adhere the dispersion material to each fiber. The frequency of ultrasonic waves is conveniently about 10 to 2000 KHz.

The suspension may be water, but organic solvents such as ethanol, methanol, acetone are preferably used.

Further, the hybrid fiber of the present invention can be subjected to sizing treatment if necessary. As the sizing agent, all known sizing agents for inorganic fibers can be used, and examples thereof include polyethylene oxide, polystyrene oxide, polymethylene, polyvinyl alcohol, and epoxy resin.

(Example) Examples are shown below.

Preparation of inorganic fiber [ ] Polydimethylsilane 100 synthesized by dechlorination condensation of dimethyldichlorosilane with metallic sodium
A polyborosiloxane having a main chain skeleton mainly composed of carbosilane units of the formula (Si-CH ₂ ) obtained by adding 3 parts by weight of polyborosiloxane per part by weight and thermally condensing the mixture at 350°C in nitrogen A polycarbosilane having a hydrogen atom and a methyl group on the silicon atom was obtained. This polymer was melt-spun, infusible treated at 190°C in air, and then fired at 1200°C in nitrogen, resulting in a fiber diameter of 13 μm and tensile strength.
Mainly silicon, with a tensile modulus of 14t/mm ² and a tensile modulus of 250Kg/mm ² .
A precursor inorganic fiber consisting of carbon and oxygen was obtained. This fiber was composed of a mixed system of an amorphous substance composed of Si, C, and O, and an aggregate composed of β-SiC and amorphous SiO ₂ having a particle size of 50 Å.

By heat-treating the above precursor inorganic fiber in air at 900° C. for 1 hour, an inorganic fiber [ ] that emits bright blue reflected light was obtained. This inorganic fiber [ ] has a fiber diameter of 13.0 μm, a tensile strength of 245 Kg/mm ² ,
It has mechanical properties with a tensile modulus of 14t/ ^mm2 ,
It had an amorphous glass layer of 0.2 μm on the fiber surface.

Preparation of inorganic fiber [] Continuous inorganic fiber [] that emits green reflected light was obtained in the same manner as in the preparation of inorganic fiber [] except that the precursor inorganic fiber was heat-treated in air at 1100°C for 30 minutes. This inorganic fiber [ ] has a fiber diameter of
13.0μm, tensile strength 240Kg/mm ² , tensile modulus 13.4t/
^It has mechanical properties of 0.3 μm on the fiber surface.
It had an amorphous glass layer.

Example 1 Inorganic fibers [
A prepreg sheet was obtained by impregnating the mold and pre-curing. Similarly surface-treated carbon fibers (polyacrylonitrile diameter, fiber diameter 7 μm) were aligned in a uniaxial direction into a sheet and impregnated with epoxy resin to obtain a prepreg sheet. The thus obtained inorganic fiber [ ] and carbon fiber prepreg were laminated alternately with the same axial direction, and then hot pressed.
A hybrid fiber reinforced epoxy composite was produced. The fiber content of this composite was 30% by volume of inorganic fibers and carbon fibers, respectively.

The obtained composite had a tensile strength of 13.6 Kg/mm ² , a tensile modulus of 9.5 t/mm ^{2 , a bending strength of 97 Kg/mm 2 ,} a flexural modulus of 7.1 t/mm ² , and an interlaminar shear strength of 7.8 Kg/mm 2 mm ² , and the bending impact value was 262 Kg·cm/cm ² . This composite exhibited a beautiful color tone reflecting the bright blue reflected light emitted from the inorganic fibers that make up the hybrid fiber.

Example 2 A plain weave cloth was manufactured using the carbon fiber used in Example 1 for the warp and the inorganic fiber [ ] for the weft, and was impregnated with the epoxy resin used in Example 1 to obtain a prepreg sheet. The thus obtained prepreg sheets were laminated and hot pressed to produce a hybrid fiber-reinforced epoxy composite.

The obtained composite had a tensile strength of 74 Kg/mm ² , a tensile modulus of 6.4 t/mm ² , a bending strength of 82 Kg/mm ² , a flexural modulus of 6.5 t/mm ² , and an interlaminar shear strength of 7.6 Kg/mm ² , the bending impact value was 259Kg·cm/ ^cm2 . This composite exhibited a beautiful color tone reflecting the bright blue reflected light emitted from the inorganic fibers that make up the hybrid fiber.

Example 3 Inorganic fibers [] were aligned in a sheet shape in the uniaxial direction, impregnated with the epoxy resin used in Example 1, and precured to obtain a prepreg sheet.
Similarly, glass fibers (E-glass) were uniaxially aligned into a sheet, and impregnated with the epoxy resin used in Example 1 to obtain a prepreg sheet. The thus obtained inorganic fiber [] and carbon fiber prepreg were laminated and hot pressed to produce a hybrid fiber-reinforced epoxy composite.

The obtained composite has a tensile strength of 78 Kg/mm ² , a tensile modulus of 7.2 t/mm ² , a bending strength of 86 Kg/mm ² , a flexural modulus of 6.4 t/mm ² , and an interlaminar shear strength of 6.9 Kg/mm ² , the bending impact value was 251 kg·cm/cm ² . This composite exhibited a beautiful color tone reflecting the bright green reflected light emitted from the inorganic fibers that make up the hybrid fiber.

Example 4 An 8-ply satin cloth was manufactured using boron fibers with a fiber diameter of 100 μm for the warp and inorganic fibers for the weft, and was impregnated with the epoxy resin used in Example 1 to obtain a prepreg sheet. The thus obtained prepregs of inorganic fibers and boron fibers were laminated and hot pressed to produce a hybrid fiber-reinforced epoxy composite. The fiber content of this composite was 15% by volume of inorganic fibers and 45% by volume of boron fibers, for a total of 60% by volume.

The obtained composite had a tensile strength of 120 Kg/mm ² , a tensile modulus of 15 t/mm ² , a bending strength of 116 Kg/mm ² , a flexural modulus of 7.5 t/mm ² , and an interlaminar shear strength of 8.3 Kg/mm ² The bending impact value was 275 kg·cm/cm ² . This composite exhibited a beautiful color tone reflecting the bright blue light reflected from the inorganic fibers that make up the hybrid fiber.

Example 5 An 8-ply satin woven cloth was manufactured using silicon carbide fibers with a fiber diameter of 140 μ as the warp and inorganic fibers [ ] for the weft, and was impregnated with the epoxy resin used in Example 1 to form a prepreg sheet. Obtained.
A prepreg of the thus obtained inorganic fiber [] and a silicon carbide fiber having a carbon core was laminated and hot pressed to produce a hybrid fiber reinforced epoxy composite. The fiber content of this composite was 15% by volume of inorganic fibers and 45% by volume of silicon carbide fibers, for a total of 60% by volume.

The resulting composite had a tensile strength of 126 Kg/mm ² , a tensile modulus of 16.2 t/mm ² , a bending strength of 105 Kg/mm ² , a flexural modulus of 8.1 t/mm ² , and an interlaminar shear strength of 7.8 Kg/mm ² , the bending impact value was 265Kg·cm/ ^cm2 . This composite reflects the bright blue reflected light emitted from the inorganic fibers that make up the hybrid fiber.
It showed a beautiful color tone.

Example 6 An 8-ply satin cloth was manufactured using aramid fiber (commercially available Kevlar) for the warp and inorganic fiber [ ] for the weft, and was impregnated with the epoxy resin used in Example 1 to obtain a prepreg sheet. The thus obtained prepregs of inorganic fibers and aramid fibers were laminated and hot pressed to produce a hybrid fiber-reinforced epoxy composite. The fiber content of this composite was 30% by volume of inorganic fibers and 30% by volume of aramid fibers, for a total of 60% by volume.

The obtained composite has a tensile strength of 77 Kg/mm ² , a tensile modulus of 4.4 t/mm ² , a bending strength of 80 Kg/mm ² , a flexural modulus of 6.2 t/mm ² , and an interlaminar shear strength of 7.1 Kg/mm ² , the bending impact value was 240Kg·cm/ ^cm2 . This composite exhibited a beautiful color tone reflecting the bright blue reflected light emitted from the inorganic fibers that make up the hybrid fiber.

Example 7 An 8-ply satin cloth was manufactured using the carbon fiber used in Example 1 for the warp and the inorganic fiber [ ] for the weft, and was impregnated with polyimide resin to obtain a prepreg. The thus obtained prepregs of inorganic fibers and carbon fibers were laminated and hot pressed to produce a hybrid fiber-reinforced polyimide composite. The fiber content of this composite is 15% by volume of inorganic fiber [] and 45% by volume of carbon fiber.
It was 60% by volume.

The obtained composite has a tensile strength of 59 Kg/mm ² , a tensile modulus of 5.8 t/mm ² , a bending strength of 61 Kg/mm ² , a flexural modulus of 5.5 t/mm ² , and an interlaminar shear strength of 6.5 Kg/mm ² , the bending impact value was 244Kg·cm/ ^cm2 . This composite exhibited a beautiful color tone reflecting the bright blue reflected light emitted from the inorganic fibers that make up the hybrid fiber.

Example 8 An 8-ply satin cloth was manufactured using the carbon fiber used in Example 1 for the warp and the inorganic fiber [ ] for the weft, and was impregnated with nylon-66 resin to obtain a prepreg. The thus obtained prepregs of inorganic fibers and carbon fibers were laminated and hot pressed to produce a hybrid fiber-reinforced nylon composite. The fiber content of this composite is 15% by volume of inorganic fibers and 45% by volume of carbon fibers, totaling 60% by volume.
It was in volume %.

The obtained composite has a tensile strength of 99 Kg/mm ² , a tensile modulus of 8.3 t/mm ² , a bending strength of 70 Kg/mm ² , a flexural modulus of 6.1 t/mm ² , and an interlaminar shear strength of 6.5 Kg/mm ² , the bending impact value was 250Kgcm/ ^cm2 . This composite exhibited a beautiful color tone reflecting the bright blue reflected light emitted from the inorganic fibers that make up the hybrid fiber.

Example 9 On pure aluminum foil (1070) with a thickness of 0.5 mm,
The inorganic fibers [] were arranged in a uniaxial direction, the aluminum foil was covered thereon, and the fibers and aluminum were composited by hot rolling at 670°C to produce a composite foil [A]. A composite foil [B] of silicon carbide fiber and aluminum foil was produced in the same manner. A total of 28 composite foils [A] and [B] were stacked alternately with their fiber axes aligned, and after being left under vacuum at 670°C for 10 minutes, they were hot pressed at 600°C to produce a hybrid fiber-reinforced composite. The fiber content of this composite was 15% by volume for both inorganic fiber [ ] and silicon carbide fiber.

The resulting composite had a tensile strength of 30 Kg/mm ² and a tensile modulus of 6.0 t/mm ² . This composite combines the natural metallic luster of the aluminum that makes up the matrix with the bright blue reflected light emitted from the inorganic fibers that make up the hybrid fibers.
It exhibited a mild blue hue.

Claims (1)

[Scope of Claims] 1 A reinforcing material made of a hybrid fiber of an inorganic fiber and at least one type of fiber selected from the group consisting of carbon fiber, glass fiber, boron fiber, aramid fiber, and silicon carbide fiber having a carbon core, In a hybrid fiber-reinforced composite having a plastic or metal matrix, the inorganic fibers are () an amorphous material consisting essentially of Si, C, and O, or () a substantially β- An aggregate consisting of crystalline ultrafine particles made of SiC and amorphous SiO ₂ , or () a mixed system of the amorphous substance described in () above and the crystalline ultrafine particle aggregate described in () above. an inner layer made of an inorganic material containing silicon, carbon, and oxygen, () an amorphous material made essentially of Si and O, () an aggregate made of crystalline SiO ₂ , or () the above (). Hybrid fiber reinforcement characterized by comprising a surface layer made of an inorganic material containing silicon and oxygen, optionally containing 5% by weight or less of carbon, which is made of a mixed system of an amorphous material and the crystalline polymer described in (2) above. complex.