JPS63324A - Fiber reinforced plastic composite and its preparation - Google Patents

Abstract

PURPOSE:To obtain the title composite having uniform dispersion of fiber, less residual stress and anisotropy, and excellent wear resistance, by injecting or infiltrating plastic into a specific fibrous material comprising a heat-resistant material or a fabric made of the material and thereafter molding and solidifying it. CONSTITUTION:In gaps among fibers of 10-70vol% (based on a composite) continuous filaments or a fabric prepared therefrom, comprising one or more members selected from among ceramic such as SiC, Si3N4, Al2O3, SiO2, ZrO2, BC, TiC etc., glasses such as borosilicate glass, high-silica glass etc., and heat- resistant materials such as carbon, metals intermetallic compd. etc., are laid with short fibers, whiskers or powder comprising one or more of the above described heat-resistant materials in a vol. fraction of 0.5-500% to obtains a fibrous material or a fabric prepd. therefrom. Next, a plastic such as a (modified) epoxy resin, a polyester resin etc., is injected or infiltrated into it and the composite is molded and solidified.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fiber-reinforced plastic composite (FRP) and a method for producing the same.

(Prior Art) Conventionally, surface-treated carbon fibers have been widely used as fibers for reinforcing plastics such as epoxy resins, modified epoxy resins, polyester resins, and polyimide resins.

(Problems to be Solved by the Invention) However, when reinforcing fibers are used to manufacture FRP by an injection method or an impregnation method, the fibers tend to be distributed in rough areas and dense areas. For this reason, it is difficult to control the fiber volume fraction (Vf) in FRP, and especially when Vf is small, it is difficult to obtain FRP with uniformly dispersed reinforcing fibers, which impairs the degree of freedom in design that is the original feature of FRP. It was

Furthermore, in FWP reinforced with only continuous fibers, the anisotropy of strength is extremely high; the strength in the longitudinal direction of the fibers is large, but the strength in the direction perpendicular to it is extremely small. Although FRP using only short fibers is isotropic, its strength is generally low.

The present invention is intended to solve the above-mentioned problems in the prior art, and its purpose is to control the fiber volume percentage by uniformly dispersing continuous fibers in the plastic matrix, and to Continuous fiber-reinforced plastic composites with improved mechanical properties such as anisotropy, residual stress, and abrasion resistance are produced by combining continuous fibers with different properties with short fibers, whiskers, or powder of heat-resistant materials. Our goal is to provide the manufacturing method.

(Means for Solving the Problems) That is, the fiber-reinforced plastic composite of the present invention is made of ceramics such as silicon carbide, silicon nitride, alumina, silica, alumina-silica, zirconia, beryllia, boron carbide, titanium carbide, etc. Continuous fibers made of at least one selected from glasses such as salt glass, high silica-containing glass, and aluminosilicate glass, and heat-resistant substances such as carbon, metals, and intermetallic compounds, or woven fabrics made from the fibers; Silicon carbide is interposed between the continuous fibers and the male fibers.

Ceramics such as silicon nitride, alumina, silica, alumina-silica, zirconia, beryllia, boron carbide, titanium carbide, borosilicate glasses.

High silica glass, aluminosilicate glass and other glasses, carbon, metals, intermetallic compounds, etc. It is characterized in that short fibers, whiskers, or powder made of at least one selected from A-type substances are uniformly dispersed in a plastic matrix.

Continuous fibers may be ceramics, glasses such as borosilicate glasses, high-silica glasses, aluminosilicate glasses, heat-resistant nonmetals such as carbon, boron, or heat-resistant metals, alloys, or intermetallic compounds such as molybdenum, tungsten, Steel, stainless steel, steel Cu Zn
, Fekt, etc. can be used alone or in combination. Properties such as fiber thickness and cross-sectional shape are selected depending on the application.

In the method of using continuous fibers, the fibers themselves are uniaxially
A method in which the fibers are aligned in multiple directions, or the fibers are used in plain weave, satin weave, patterned weave, twill weave, leno weave, spiral weave,
There are methods of using it in various fabrics such as three-dimensional fabrics, and methods of using it as a chiselled fiber.

Heat-resistant substances constituting the short fibers, whiskers, or powder interposed between the fiber gaps of continuous fibers include silicon carbide, silicon nitride, alumina, silica, alumina-silica, zirconia, beryllia, boron carbide, and ceramics such as titanium carbide. , glass, carbon, metals, and intermetallic compounds.

The proportion of short fibers, whiskers or powder of the heat-resistant material is preferably 0.5 to 500 by volume to the continuous fibers.

Next, the plastics used as a matrix in the present invention include epoxy resin, modified epoxy resin, polyester resin, polyimide resin, phenol resin, polyurethane resin, polyamide resin, polycarbonate resin, silicone resin, phenoxy resin, polyphenylene sulfide, fluororesin, and carbonized resin. Examples include hydrogen resin, hydrogen-containing resin, acrylic acid resin, ABS resin, ultra-high molecular weight polyethylene, modified polyphenylene oxide, and polystyrene. These plastics can be used alone or in combination.

The reinforcing fibers used in the plastic composite of the present invention can be suitably produced by a suspension dipping method.

An example of the suspension dipping method is to unwind continuous fibers wound around a bobbin or a continuous fiber bundle made by bundling an appropriate number of continuous fibers, or to transform a woven fabric made from continuous fibers into short fibers,
Examples include a method of immersing in a liquid in which at least one of whiskers or powder is suspended, and attaching short fibers, Rice force, or powder to the surface of each continuous fiber or fiber of a woven fabric.

When dipping continuous fiber bundles or fabrics with a large number of fibers,
It is preferable to apply vibration using ultrasonic waves to uniformly adhere short fibers, whiskers, or powder to each fiber. The frequency of ultrasonic waves is conveniently about 10 to 2000 KHz.

The suspension may be in water, but it may also be in an organic solvent, such as ethanol,
Methanol and acetate are preferably used. When the above-mentioned organic solvent is used as a suspension, when the fibers are sized, short fibers, etc. can be easily attached by dissolving the sizing agent, and drying is quick because the solvent has higher volatility than water. This has the advantage of improving productivity.

The concentration of short fibers, whiskers, or powder in the suspension is not particularly limited, but if it is too small, it will not adhere uniformly to the continuous fibers, and if it is too large, the amount of adhesion will be too large, so 0.5
~30? /l is preferred.

From the thus obtained fibrous body or its woven fabric, l”
RP can be manufactured. The manufacturing method is
Examples include hand lay-up method, mated metal die method, breakaway method, filament winding method, hot press method, autoclave method, continuous drawing method, and methods similar thereto. - Taking the hot press method as an example, according to this method, a fibrous body or its fabric is impregnated with plastic and then precured to prepare a prepreg sheet, which is then subjected to ffl; ML and then hot press. It can be made into a plate-like composite by applying pressure and heating.

(Examples) The present invention will be explained in further detail in the following examples. 2. The present invention is not limited to the following examples.

Example 1 Silicon carbide whiskers (average diameter approximately (1.2μ, average length approximately 100μ) 52 were placed in a treatment tank containing 1 ton of ethanol, and then suspended by applying ultrasonic vibration to adjust the suspension. did.

A fiber bundle (500 threads) of silicon carbide fibers was unwound from the bobbin, knotted with a movable roll so that the immersion time was about 15 seconds, immersed in the suspension, and then pressed with a pressure roll. Thereafter, it was wound up onto a bobbin and dried in the air at room temperature. 0.02 whiskers per 10m of fiber bundle? It was attached.

This treated fiber bundle is aligned in one axis direction, and the city ffi is placed on it.
The prepreg was impregnated with bisphenol A type epoxy resin and precured to obtain a prepreg with a thickness of 0.15 rItm. After laminating these, hot pressing was carried out at 170° C. and 7 kq/− for 4 hours to obtain a composite with a thickness of 2 mm.

When we examined a cross section of this complex using a scanning electron microscope, we found that
It was observed that silicon carbide whiskers were partially attached to the fiber surface and were uniformly dispersed in the matrix resin, and the fibers were dispersed in the composite without coming into contact with each other. The fiber content of this composite was 55 volumes. The tensile strength of the composite is 160 kq/d, and the interlaminar shear strength is 1
It was 0kf/-.

Example 2 Silicon carbide whiskers and silicon nitride whiskers used in Example 1 (average diameter approximately 0.3μ, average length approximately 200μ)
The same method as in Example 1 was repeated except that 52 of each were used in combination and the immersion time was changed to 20 seconds. The amount of whiskers deposited per 10 m of fiber bundle was 0.03 t.

The fiber bundles were arranged in a sheet shape in one direction, impregnated with a commercially available phenol-novolac type modified epoxy resin, and then precured to obtain a prepreg sheet with a thickness of Om 15 mm. After laminating these sheets, 170℃,
Hot pressed at 17-/- for 4 hours to a thickness of 2 vtm.
The complex was obtained.

The fiber content of the composite was 55% by volume.

When we examined a cross section of this complex using a scanning electron microscope, we found that
A large number of whiskers were observed in the fiber problem, and almost no contact between continuous fibers was observed. The tensile strength of the composite is 1
70 kq/j, and the interlaminar shear strength was 10 da/-.

(Effects of the Invention) The composite of the present invention can be made of various combinations of continuous fibers, short fiber whiskers or powder of a heat-resistant material, and plastic as a matrix, and can satisfy a wide range of required properties. Furthermore, since the fibers are uniformly dispersed in the composite and there is very little contact between continuous fibers in the composite, the strength of the continuous fibers in the direction perpendicular to the fiber axis is significantly improved.

Furthermore, the production method of the present invention is an excellent method for practical use because it can easily produce a composite having the above-mentioned excellent properties.

Claims (5)

[Claims] (1) Silicon carbide, silicon nitride, alumina, silica, alumina-silica, zirconia, beryllia, boron carbide,
Continuous fibers made of at least one selected from ceramics such as titanium carbide, glasses such as borosilicate glasses, high silica-containing glasses, and aluminosilicate glasses, and heat-resistant substances such as carbon, metals, and intermetallic compounds; A woven fabric made from fibers, and ceramics such as silicon carbide, silicon nitride, alumina, silica, alumina-silica, zirconia, beryllia, boron carbide, and titanium carbide interposed between the fibers of the continuous fibers.
In a matrix, short fibers, whiskers or powder consisting of at least one selected from glasses such as borosilicate glass, high silica content glass and aluminosilicate glass, and heat-resistant substances such as carbon, metals and intermetallic compounds are used. A fiber-reinforced plastic composite characterized by being uniformly dispersed in a certain plastic. (2) The fiber-reinforced plastic composite according to claim 1, wherein the volume ratio of the short fibers, whiskers, or powder of the heat-resistant substance to the continuous fibers is 0.5 to 500%. (3) The blending ratio of continuous fibers to the composite is 10 to 7
The fiber-reinforced plastic composite according to claim 1, characterized in that the content is 0% by volume. (4) Silicon carbide, silicon nitride, alumina, silica, alumina-silica, zirconia, beryllia, boron carbide,
continuous fibers consisting of at least seeds selected from ceramics such as titanium carbide, glasses such as borosilicate glasses, high silica-containing glasses, aluminosilicate glasses, heat-resistant materials such as carbon, metals, and intermetallic compounds; Silicon carbide, silicon nitride, alumina, silica, alumina-silica, zirconia, beryllia, interposed in the fiber gaps of continuous fibers,
Short fibers made of at least one selected from ceramics such as boron carbide and titanium carbide, glasses such as borosilicate glass, high silica-containing glass, and aluminosilicate glass, and heat-resistant substances such as carbon, metals, and intermetallic compounds. , whiskers or powder, or a fabric made from the fibers, which is injected or impregnated with plastic, and then molded and solidified. (5) The fibrous body or the woven fabric of the fibrous body is manufactured by attaching short fibers, whiskers, or powder of a heat-resistant substance to continuous fibers or a woven fabric thereof. A method for producing a fiber-reinforced plastic composite according to item 4.