JPH01111040A - Blended fabric and molded article thereof - Google Patents

Abstract

PURPOSE: To obtain the subject woven fabric excellent in drapeability, capable of being laminated along a mold of a complicated shape and suitable as a composite material excellent in mechanical characteristics by forming a yarn prepared by carrying out combined knitting of a reinforcing fiber bundle with a thermoplastic resin fiber bundle at a specific number of twists into a woven fabric. CONSTITUTION: (A) A reinforcing fiber bundle having preferably >=1% elongation such as carbon fibers or glass fibers and (B) a fiber bundle of a thermoplastic resin (e.g. polyethylene) having preferably >=100 deg.C melting point or softening point are subjected to combined knitting at 5-80 turns/m number of twists to provide a yarn, which is then used to afford the objective woven fabric.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a mixed fabric (intermediate material) consisting of a reinforcing fiber bundle and a thermoplastic resin fiber bundle to provide a fiber-reinforced thermoplastic resin composite material, and a process for processing the mixed fabric. This relates to a molded product formed by pressure molding. The blended fabric of the present invention allows the fiber-shaped thermoplastic resin to satisfactorily impregnate the reinforcing fiber bundle as a matrix resin during molding, resulting in a molded product with excellent mechanical properties (
The molded products are widely used in the aerospace and general industrial fields.

[Prior art and problems]

In recent years, carbon fibers have been used in the form of long fibers or short fibers in combination with various matrix resins because they have high specific strength and specific modulus. advanced mechanical properties,
In the aerospace field and general industry, which require heat resistance, thermosetting resins such as unsaturated polyester resins, epoxy resins, and polyimide resins have conventionally been used as matrix resins in composite materials. However, since these matrix resins have the disadvantage of being brittle and having poor second impact resistance, improvements have been sought.

In addition, thermosetting resins have problems such as difficulty in preserving and managing prepregs in relation to the life of the resin, and further problems such as long molding time and low productivity.

On the other hand, thermoplastic resin composite materials have excellent Wi-impact resistance, easy storage management of prepregs, short molding time, and the possibility of reducing molding costs. In particular, by using a thermoplastic resin that can serve as a matrix resin in the tJAN shape and combining it with reinforcing fiber bundles, an intermediate material such as a fabric with excellent drapability (flexibility) can be obtained, and it can be heated and By applying pressure, it is possible to produce molded products with relatively complex shapes in a cylinder.

Interlacing two or more types of fibers of the same or different types,
Alternatively, it is known to mix by jet mixing etc. (
U.S. Patent No. 4,219,997F3, 4,21
No. 8,869 Mei 1111, etc.).

In addition, the combination of carbon fiber and thermoplastic resin fiber is
Japanese Unexamined Patent Publication No. 60-209033, No. 60-20903
This is disclosed in Publication No. 4. This disclosed technology is characterized by closely blending carbon fibers and thermoplastic resin fibers, and uses an air jet or the like to forcibly mix both fibers.

In this technology, reinforcing m-fiber bundles and thermoplastic resin fiber bundles are closely blended, so when creating a molded product,
It is possible to obtain a molded product with few defects by heating and fusing at a relatively low molding pressure (20 kQ/am' or less). However, on the other hand, when tightly blending reinforcing fiber bundles and thermoplastic resin fiber bundles, forced mixing is used, either because the operation is troublesome or because the reinforcing fiber bundles and thermoplastic resin fiber bundles are mixed during manufacturing. This causes breakage of single fibers and entanglement of single fibers, and fabrics obtained from such mixed fibers have disadvantages such as poor appearance and loss of the original properties of the fiber bundle. Therefore, the composite material obtained from the mixed fiber fabric according to the above technique did not sufficiently reflect the original properties.

[Object, structure, and operation of the invention]

In order to obtain a fiber-reinforced thermoplastic resin composite material that overcomes the above-mentioned drawbacks, the present inventors investigated a mixed fiber consisting of a reinforced braided wire and a thermoplastic resin miscellaneous material, and a molded product thereof. This led to the invention.

The present invention is as follows.

In a fabric that uses a mixture of reinforcing fiber bundles and thermoplastic resin fiber bundles, the number of twists in which both 5 ast bundles are intertwined is 5 to 80 times/
A blended fabric characterized in that it is a yarn of m.

A molded article obtained by pressure-molding a mixed woven fabric made of a mixture of reinforcing fiber bundles and thermoplastic resin fiber bundles, which is a yarn with a twist count of 5 to 80 times/■ in which both lll and 11 bundles are interlaced.

According to the present invention, in a fabric in which reinforcing fiber bundles and thermoplastic resin fiber bundles are mixed, by using a V-n in which both fiber bundles are interlaced, reinforcing sii, w and thermoplastic resin can be relatively easily combined. When producing an intermediate material consisting of fibers and producing a molded article from the obtained intermediate material, 1, it can be heated and fused at a relatively low pressure (20 kO/am' or less), and there are few defects. A molded product with improved mechanical properties can be obtained.

The present invention relates to a woven fabric in which reinforcing fiber bundles and thermoplastic resin fiber bundles are mixed, and the mixed woven fabric is characterized in that both fiber bundles are interlaced yarns, and this mixed woven fabric (intermediate material) It is a molded product made from. The interlacing of both IIH bundles can be easily produced using a general-purpose false twisting machine or the like, and fabrics of various textures can be easily manufactured from the interlaced yarns by known methods.

Composite materials (molded articles) of arbitrary shapes can be made using a mixed fabric (intermediate material) consisting of interlaced yarns of reinforcing fiber bundles and thermoplastic resin fiber bundles.

The blended fabric of the present invention is flexible and has excellent re-draping properties, so it is easy to handle and can be formed into 8I layers along a mold with a complex shape. By molding and processing under suitable molding conditions, a composite material (molded product) with excellent mechanical properties can be obtained.

The reinforced m-ray bundle in the present invention preferably has an elongation of 1.0%.
This is a single m-ray bundle of the above-mentioned carbon 11s miscellaneous, glass fiber, or aromatic polyamide fiber, or a IIH bundle using these in combination.

Although the fiber shape, thickness, and number of filaments can be set arbitrarily, the diameter of the single li-fiber is generally 20 μm or less.

In the case of carbon fiber bundles, the single fiber diameter is 4 to 10 μm and the strength is 10
0 kgf/am2 or more, elastic modulus 10x 10” kgf
II miscellaneous bundles with a diameter of /m2 or more are preferable, and those that have been surface-treated are also preferable in order to improve the adhesion between the resin and the carbon fibers.

In addition, since the reinforcing fiber bundle and the thermoplastic resin m-line bundle are crossed, there is no need to particularly improve the handling of the reinforcing fiber bundle and the thermoplastic resin fiber bundle, and the so-called so-called sizing agent is not used. , non-sized fiber bundles are preferred. In the case of non-sized fiber bundles, the fiber bundles open better during molding, so
The resulting molded product has fewer defects and improved mechanical properties.

The 11 bundles of thermoplastic resin in the present invention are preferably made into fibers from a thermoplastic resin having a melting point or softening point of 100° C. or higher, and the fiber shape, thickness, and number of filaments can be set arbitrarily. The denier is generally 1 to 15 denier.

Types of thermoplastic resins include, for example, polyethylene, polypropylene, polyamide, polyethylene terephthalate, polycarbonate, polyetherimide,
polyether sulfone, polyphenylene sulfide,
Examples include polyetheretherketone, polyarylate, and polysulfone. Coloring agents, additives, fillers, flame retardants, etc. can be included in the thermoplastic resin fibers.

The present invention provides a fabric in which reinforcing fiber bundles and thermoplastic resin fiber bundles are mixed, and the number of twists in which double-sided wire bundles are intertwined is 5 to 8.
It is a mixed fabric with 0 turns/m yarn. A particularly preferred number of twists is 20 to 40 twists/1. Number of twists is 5 times/m
If it is less than 1, there will be no twisting effect, and especially when a non-sized reinforced 11M bundle is used, the yarn will easily open due to external force and spoil the shape of the yarn. Workability is significantly deteriorated due to entanglement. When the number of twists exceeds 80 times/m, the yarn becomes narrow due to the excessive number of twists, which tends to result in a coarse structure when made into a fabric, and the fiber bundle does not open well during molding. The resulting molded product is prone to defects and its mechanical properties are also slightly degraded.

The ratio of the interlaced reinforcing fiber bundles to the thermoplastic resin fiber bundles is determined by considering the mechanical properties of the composite material finally obtained by molding, and the reinforcing fibers are 40 to 10% by volume, which forms the matrix. It is preferable that the content of thermoplastic resin fibers is 30 to 60% by volume. In order to achieve such a ratio,
Before intersecting, it is necessary to predetermine the volume fraction of the bidirectional wire bundles and intersect each IIN bundle with a corresponding yield (weight per fiber bundle 1). Also,
It is also necessary to change the single fiber diameter and the number of filaments of the double wire bundle as appropriate depending on the type, property, or purpose of use of the double wire bundle.

The molded product of the present invention is obtained by molding the mixed fabric. The molded product is made by combining the reinforcing fibers and the resin by passing the mixed fabric alone or in a layered state through a hot press heated above the melting point of the 5-utt thermoplastic resin that serves as the matrix, between rollers or through slits. The molded product is a fiber-reinforced thermoplastic resin material with excellent mechanical properties and the like.

(Effects of the Invention) According to the present invention, in a fabric in which reinforcing fiber bundles and thermoplastic resin fiber bundles are mixed, by using yarn in which double-sided wire bundles are interlaced, reinforcing fibers and thermoplastic resin fibers can be relatively easily combined. A mixed silk material (intermediate material) is produced, and there is little damage to both IIH bundles, so molded products obtained from this intermediate material (fabric) by heating and pressurizing are superior in terms of moldability and physical properties. It has a balanced nature.

(Examples and Comparative Examples) Example 1 Carbon fiber bundle (Besphite H-7-3) was used as reinforcing fiber.
K (non-sized product), single fiber diameter: 1μ, number of filaments: 3000) was used, and polyetheretherketone fiber (single denier: 9 denier, number of filaments = 100) was used as the thermoplastic resin fiber bundle. Then, a yarn with 30 twists/peng was produced using a false twisting machine. Plain weave fabric (carbon fiber basis weight: approx. 200! J/I) is made from this yarn.
' , Thermoplastic resin fiber weight: approx. 1000/m '
) was made and cut to predetermined dimensions to produce a woven fabric.

After laminating 20 sheets of this fabric, it was placed in a mold, heated for 10 minutes in a hot press, and then pressurized (380℃, 20kg/cm).
' ) L/, a laminate was obtained. Polish the cross section of the laminate,
When observed under a microscope, no defects such as voids were observed. The fiber volume content is shown in Table 1. A test piece was cut out from this molded plate, and a bending test in the warp direction and interlaminar shear strength (ILSS) were measured. The results are shown in Table 1. All exhibited good mechanical properties.

Comparative Example 1 Carbon II fiber bundle Besphite ■H-cho- as reinforcing fiber bundle
7-3K (non-size product),? 111 fiber diameter near μm
Polyether ether ketone I fiber (single yarn denier: 9 denier, number of filaments = 100) was used as a thermoplastic resin fiber bundle.
A yarn with three twists/ugliness was prepared using a false twisting machine. An attempt was made to make a plain weave from this yarn, but the yarn broke frequently in the guides, so the fabric could not be manufactured.

Comparative Example 2 “Carbon II miscellaneous bundle (Besphite HT7) was used as a reinforcing fiber bundle.
-3K (non-sized product), single fiber diameter.

7 μ-, number of filaments: 3000), polyether ether ketone fiber m was used as a thermoplastic resin fiber bundle.
<Single yarn denier: 9 denier, number of filaments = 10
A yarn with a twist count of 85 times/m was produced using a false twisting machine. Plain weave fabric (carbon fiber basis weight: approx. 200g/sr', thermoplastic resin fiber basis weight: approx. 10) is made from this yarn.
h/m') and cut it into predetermined dimensions to produce a fabric.

After laminating 20 sheets of this fabric, it was placed in a mold, heated in a hot press for 10 minutes, and then pressurized (380℃, 20kg/c
s+') L/, a laminate was obtained. When the cross section of the laminate was polished and observed under a microscope, defects such as voids were found in some parts. A test piece was cut out from this molded plate, and a bending test in the warp direction and interlaminar shear strength (ILSS) were measured. The results are shown in Table 1. Example 2 A carbon fiber bundle (Besphite's HT7-
Using polyetherimide fiber (single yarn denier: 9 denier, number of filaments = 100) as 111 bundles of thermoplastic resin A yarn with a twist number of 30@/I was produced using a false twisting machine. 4 pieces of satin fabric from this yarn (carbon fiber basis weight: approx. 380g/+e'
, thermoplastic resin fiber basis weight: approximately 190 g/m') was prepared and cut into predetermined dimensions to produce a fabric.

After laminating 8 layers of this fabric, it was placed in a mold, heated in a hot press for 10 minutes, and pressurized (380°C, 20k (J/c)
n+2) L, a laminate was obtained. When the cross section of the laminate was polished and inspected for IJ using a microscope, no void defects were observed. The fiber volume content is shown in Table 2. A test piece was cut out from this molded plate, and a bending test in the warp direction and interlaminar shear strength (ILSS) were measured. The results are shown in Table 2. All exhibited good mechanical properties.

Comparative Example 3 Carbon fiber bundle (Besphite HTA7) was used as reinforcing fiber bundle.
-3K, single fiber diameter: 1μ-, number of filaments: 3
Using polyetherimide 1111 (single filament denier: 9 denier, number of filaments: 100) as a thermoplastic resin fiber bundle, it was tightly blended using an air jet method (pressure crab 5 to 7 ka/cm2). , so-called commingle yarn was produced. 4 pieces of satin fabric from this yarn (carbon fiber basis weight: approx. 380g/m'
, thermoplastic resin fiber basis weight: approximately 19h/+e') was prepared and cut to a predetermined size to produce a fabric.

Claims (5)

[Claims] (1) A woven fabric made of a mixture of reinforcing fiber bundles and thermoplastic resin fiber bundles, characterized in that the two fiber bundles are interlaced and the yarn has a twist count of 5 to 80 times/m. (2) Mixed use according to claim (1), wherein the reinforcing fiber bundle is a single fiber bundle of carbon fiber, glass fiber, or aromatic polyamide fiber with an elongation of 1.0% or more, or a fiber bundle using these in combination. fabric. (3) The thermoplastic resin fiber bundle has a melting point or softening point of 100°C
Claims (1) which are fiber bundles of the above thermoplastic resin
). (4) Claim (1) in which the ratio of the interlaced reinforcing fiber bundles and the same thermoplastic resin fiber bundles is 40 to 70% by volume of the reinforcing fiber bundles and 30 to 60% by volume of the thermoplastic resin fiber bundles. Mixed fabrics as described. (5) A molded product obtained by pressure molding a woven fabric made of a mixture of reinforcing fiber bundles and thermoplastic resin fiber bundles, which is a yarn with a twist count of 5 to 80 turns/m, in which both fiber bundles are interlaced. .