JPH0643650B2 - Fiber material for resin reinforcement - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin-reinforcing fiber body used for producing a fiber-reinforced resin body (FRP).

[Prior Art] FRP is manufactured by impregnating a reinforcing fibrous body with a liquid thermosetting resin and curing the resin, and is widely used for bathtubs, automobile bodies, bumpers and the like.

FRP manufacturing methods include press molding method, resin injection method (RI method), hand layup method (HL method)
Etc. are known.

In order to obtain an FRP having high strength and heat resistance, it is necessary to use a reinforcing fiber body having high strength and heat resistance. Inorganic fibers such as glass fibers and alumina fibers are suitable fibers for this purpose, of which glass fibers are the most widely used.

Such fibers are often used in the form of a plurality of long monofilaments, preferably provided with a sizing agent and aligned and bundled.

It can be obtained by randomly depositing strands on a moving conveyor in a curved shape with a long length, or by randomly depositing strand cuts and attaching a binder to bind the strands together. Mats such as continuous strand mats (CSM) and chopped strand mats (CCM) are widely used as FRP resin-reinforcing fiber bodies.

Alternatively, a woven fabric using a strand or an aligned product (roving) thereof is also widely used as a resin-reinforcing fiber body for FRP.

[Problems to be Solved by the Invention] Since a large number of monofilaments are bundled in the above-mentioned mat or woven fabric using strands or rovings, when the bulk density is large and the weight per unit area is constant, In order to obtain a FRP having a small thickness and a large thickness, it is necessary to use a large number of mats or woven fabrics. However, the obtained FRP peels off along the interface between the laid mats or woven fabrics. There are easy drawbacks.

When these mats or fabrics are impregnated with a liquid resin, it is difficult for the resin to penetrate into the inside of the strands.
There is a problem that the RP is apt to be impregnated with resin, and in the case of deep drawing, the mold fitting is insufficient.

Attempts have been made to bulky strands or rovings, but those that have been bulked by conventional methods are weaving,
It is stretched by the tension applied at the time of cutting and loses bulkiness.

It is an object of the present invention to obtain a resin-reinforcing fiber body having a low bulk density, a large thickness, a good resin impregnation property, no delamination of FRP, and a good mold fit.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a string-like body obtained by defibrating a fiber-reinforced resin body used for producing a fiber-reinforced resin body by defibrating a bundle of a large number of filaments. And, at a place spaced apart from the cord-shaped body, a entangled portion in which filaments forming the cord-shaped body are entangled with each other is formed, and the cord-shaped body is divided into a plurality of sections by each entangled portion, and each section In, the string-shaped body includes a first group filament aligned in the longitudinal direction of the string-shaped body and a second group filament defibrated and swelled in a direction orthogonal to the longitudinal direction to form the string-shaped body. The filaments belonging to the first group filaments in one section belong to the second group filaments in other sections so that the entire lengths of the respective filaments are equal to each other. (Collectively referred to as the body).

Next, the present invention will be described more specifically.

FIG. 1 is an enlarged plan view for schematically explaining the structure of the cord-shaped body 1 used in the present invention. The cord-shaped body 1 is obtained by defibrating a bundle of a large number of filaments and has a cord-shaped structure. A entangled portion 2 in which filaments constituting the string-shaped body 1 are intertwined with each other is formed at a position spaced apart from the body 1, and the entangled portion 2
The string-like body is divided into a plurality of sections 3 by the first group filament f ₁ aligned in the longitudinal direction of the string-like body 1 in each section 3 and the longitudinal direction after being disentangled. And a second group filament f ₂ swelling in a direction orthogonal to each other,
The filaments that belong to the first group filament in a certain section are made to belong to the second group filament in other sections so that the entire lengths of the filaments forming the cord-like body are equal.

The filaments that should constitute the above string-shaped body (simply referred to as a string-shaped body) include glass fibers, alumina fibers, silica fibers, inorganic fibers such as zirconia fibers, titania fibers, organic fibers such as Kevlar fibers, and brass fibers. The metal fiber, the carbon fiber, or the composite fiber obtained by mixing these fibers can be used, but it is preferable to use the glass fiber or the composite fiber mainly containing the glass fiber.

It is suitable that the thickness of the fibers is 3 to 30 μ, preferably 5 to 25 μ, and a sizing agent is added to these fibers to give 50 to 10 μm.
Retention time of the fiber bundle in the bulking device, such as 000, preferably 200 to 50,000, which are aligned to form a fiber bundle, and the fiber bundle is bulked with a high supply rate to the bulking device. The cord of the present invention is selected by shortening the air supply hole of the bulking device and by selecting the bulking condition so that the bulking condition is easily changed, for example, by opening the air supply hole of the bulking device so as to be orthogonal to the tubular passage of the bulking device. A shape can be obtained.

When the air supply holes are opened so as to cross the tubular passages, the air blown into the tubular passages from the air supply holes flows in the tubular passages in a certain direction (outlet direction of the fibers), However, if the air supply holes are opened so as to be orthogonal to the tubular passages, part of the air will also flow out in the direction of the fiber inlet, and this will be caused by variations in the diameter of the fiber bundle and shaking of the fiber bundle. Outflow due to fluctuations in the relative position of the fiber bundle at the inlet and outlet of the tubular passage (for example, the fiber bundle is positioned so as to contact the lower surface of the passage at the inlet, or at the center of the outlet passage) The ratio between the amount of air and the amount of air flowing out toward the inlet fluctuates, and the bulking condition fluctuates.

Further, when the residence time in the bulking device is long, fluctuations in the bulking conditions are easily averaged, but when the residence time is short, averaging becomes difficult.

In addition, so that bulky operation is performed with a small tension,
It is desirable that the drawing speed of the cord-shaped body obtained by the method of the present invention is sufficiently lower than the supply speed of the fiber bundle as the raw material.

As the bulking device, an air processing machine AT-501 manufactured by Aiki Co., Ltd. can be preferably used.

As the sizing agent, it is preferable to use one having a small adhesive force such as an epoxy resin, and the amount of the sizing agent added is 0.1 to 10% by weight, preferably 0.2 to 5% by weight as a solid content.

In the string-like body 1, entangled portions 2, 2 ... In which filaments forming the string-like body are entangled with each other are formed at locations spaced by a predetermined distance in the longitudinal direction.

In the entangled portion 2, the filaments are monofilament-shaped or a plurality of filaments are aligned and entangled in a braided shape, and the filaments are slightly twisted due to the entanglement.

By forming the entangled portion 2, the filaments forming the string-shaped body 1 are combined so as not to be separated from each other.

The distance between the entangled portions 2 is 1 to 30 mm, preferably 3 to 15 mm. If this length is too small, the ratio of the entangled portion 2 to the entire length of the cord-like body becomes large, the bulkiness of the cord-like body 1 becomes poor, the thickness of the reinforcing fiber body becomes small, and the impregnation property of the resin decreases. To do. If this length is too large, the filaments of the first group and the filaments of the second group are easily separated.

The length of the entangled portion 2 is 0.1 to 5 mm, preferably 0.2 to 3
mm is appropriate. If this length is too large, the bulkiness of the cord 1 becomes poor, and if this length is too small, the filaments forming the cord 1 are easily separated.

The entwined portion 2 divides the string-like body 1 into a plurality of sections 3, 3, ... In the section divided and sectioned by the entanglement unit 2,
The string-like body 1 is a first group of filaments f ₁ which are aligned in the longitudinal direction of the string-like body and are preferably twisted,
It preferably contains a second group of filaments f ₂ which are defibrated into monofilaments and swell in the direction orthogonal to the longitudinal direction. The filaments belonging to the second group are defibrated and bulged outward in a substantially arc shape from the axis line connecting the entangled portions (longitudinal direction of the cord-like body), and preferably defibrated in the monofilament shape. The direction of this bulge is not limited to a specific plane including the axis, but is random, and when viewed macroscopically (on average), the cord-like body has a substantially round cross section.
It is suitable that the maximum value of the distance from the axis of this bulge is about 2 to 10 mm.

The filaments belonging to the first group are aligned in the longitudinal direction. This filament is preferably provided with a twist in the S direction or the Z direction, and this twist improves the integrity of the filaments belonging to the first group.

When focusing on a certain specific section, the length of the filament f ₁ belonging to the first group is shorter than the length of the filament f ₂ belonging to the second group, and when tension is applied to the string-like body, the filament f ₁ belonging to the first group However, it antagonizes tension.

The filament f ₂ belonging to the second group is longer than the filament f ₁ belonging to the first group, swells outward from the longitudinal direction, and does not antagonize the tension by itself.
f ₂ is entangled with the filament f ₁ belonging to the first group at the entanglement portion 2, and the tension applied to the string-shaped body 1 is absorbed by the filament f ₁ belonging to the first group, so that the tension is applied to the string-shaped body 1. Even if given, the length of this section does not substantially extend longer than the length of the filament f ₁ belonging to the first group, and the filament f ₂ belonging to the second group is stretched and the bulkiness is not lost. .

The number of filaments belonging to the first group is suitably 10 to 50% of the total number of filaments. If this number is too large, the bulkiness of the cord 1 is poor, and if this number is too small, the strength of the cord 1 in the longitudinal direction tends to decrease.

When paying attention to a certain specific section, the filament f ₁ shown by the broken line belonging to the first group and the filament f ₂ shown by the solid line belonging to the second group are entangled and mixed at the entangled portion at the end of this section. Filaments belonging to the first group in the next section
It is divided into f ₁ ′ and filament f ₂ ′ belonging to the second group.

At least part of the time f ₁ is 'belongs to the second group and proceeds to, at least a portion of f ₂ is f _1' f ₂ will belong to the second group and proceeds to. Such a transition (change of affiliation) to a different group is performed at random, but when a certain filament is focused, this filament is first in each section.
The number of times of belonging to the group is almost equal to the number of times of belonging to the second group, and the total lengths of the filaments forming the string-like body are equal.

The twisting directions given to the filaments of the first group are reversed in some places, and the number of twists in the S direction, the twists, and the Z direction is almost the same in the whole string-like body, and the twisting occurs in the string-like body. There is no such thing.

Inversion of the twisting direction may occur within one section, in which case a slight length of untwisted portion may occur at the inversion portion.

The filaments belonging to the first group may bulge slightly outward in such an inverted portion, but this bulge is extremely smaller than the bulge of the filaments of the second group, and the filament-like shape described above. It does not affect the antagonistic force exerted on the tension applied to the body.

It should be noted that the signs of the entangled portions, the distance between the entangled portions, the number of filaments belonging to the first group in each section, the degree of swelling of the filaments belonging to the second group, etc. are constant values over the entire length of the cord-shaped body. In practice, it is meaningless to control the above, and by keeping these in the above range, the object of the present invention can be sufficiently achieved.

Further, the string-like body can be composed of a relatively soft fiber such as glass fiber or organic fiber, but it can also be composed of a brittle fiber such as silica fiber, and such a string-like body can be provided with tension. The bulky property is not lost and the heat resistance is great.

In the present invention, the reinforcing fiber body is composed of a mat (main mat) using a string-shaped body.

Since the cord-like body does not stretch even if tension is applied and the bulkiness is not lost, the present fabric can be made of the cord-like body for both the weft yarn and the warp yarn, but only one of them (preferably the weft yarn). It is also possible to use a cord-like body for (only). Further, as the present woven fabric, a non-woven fabric to which weft threads and warp threads are adhered can be used.

As described above, the cord-like body has a substantially round cross section, and when the weight per unit area is constant, this woven fabric has a thickness about three times that of a woven fabric using ordinary strands or rovings. Since the fibers are defibrated and impregnated with the liquid resin, the impregnation is good.

This performance is comparable to the woven fabric using spun yarn, and the manufacturing labor is much smaller than that of the spun yarn, and this woven fabric is composed of a fiber much longer than the spun yarn. ,
By using this woven fabric for FRP reinforcement, it is possible to obtain an FRP having higher strength than in the case of using a spun yarn woven fabric.

A continuous string-like body or a string-like body cut into a predetermined length (25 mm or more, preferably 50 mm or more is desirable) is used, and these are dropped and deposited on a moving conveyor according to a conventional method, and a binder is used. This mat can be obtained by adding.

Deposition amount is 50 to 5,000 gr / m ² , preferably 100 to 3,000 gr / m ² .
m ² is suitable, and the same amount of normal CS, C
A mat having a thickness about 5 times that of SM and having a good resin impregnation property can be obtained. Also, since this mat is composed of continuous filaments, by using this mat,
It is possible to obtain a uniform FRP having strength comparable to that when using the conventional CM and CSM.

In addition, since the cord-like body is defibrated and has the second group filaments that swell in the direction orthogonal to the longitudinal direction, the cord-like bodies are entangled with each other, so the amount of binder used is larger than that of ordinary CM and CSM. Can be reduced to about 50%, and FRP caused by the binder
The quality deterioration of can be reduced.

Furthermore, since the cord-like body that constitutes the mat includes the second group of filaments that have been defibrated and swelled in the direction orthogonal to the longitudinal direction, a plurality of mats are stacked and used for reinforcing the FRP. In this case, since the filaments of the second group are entangled with each other, delamination of FRP does not occur,
Further, FRP having a smooth surface can be obtained, and the mold familiarity is also good.

The thermosetting resin such as unsaturated polyester resin or epoxy resin is added to the resin-reinforcing fiber body of the present invention, and the resin amount in the FRP is 4
FRP can be obtained by impregnation so as to be about 0 to 80 wt% and by press molding method, RI method, HL method and the like. The type of resin used and the molding method are the same as in conventional methods, and therefore detailed description is omitted.

[Operation] A string-like body obtained by defibrating a bundle of a large number of filaments, in which entangled portions in which the filaments constituting the string state are entangled are formed at positions separated from each other. The entangled portion divides the cord-shaped body into a plurality of sections, and in each section, the cord-shaped body is defibrated and orthogonal to the longitudinal direction with the first group filaments aligned in the longitudinal direction of the cord-shaped body. The second group filaments bulging in the direction are included, and the filaments that belong to the first group filament in a certain section belong to the second group filament in other sections so that the entire lengths of the filaments forming the string-like body are equal to each other. By constructing the mat using a string-like body, the bulk specific gravity is reduced to increase the thickness without decreasing the strength of the mat, and the impregnation property of the liquid resin is increased to improve the mold conformity. Further tighten if good only to prevent delamination.

[Example 1] A glass bundle (filament) having a thickness of 9 µ was provided with 0.2 wt% of an epoxy sizing agent as a solid component and 4,000 bundles were bundled, and a hole was formed orthogonally to a tubular passage. Air processing machine AT- manufactured by Aiki Co., Ltd., equipped with air supply holes
501 was used to produce a cord-like body having the following specifications.

The fiber bundle supply speed is 120 m / sec, the drawing speed is 110 m / sec, and the average pressure of compressed air is 5.0 kg.
/ Cm ² G.

Specifications of the cord-like body The average length of the entangled part is 3 mm, the average distance between the entangled parts is 8 mm, the average number of filaments belonging to the first group is 1,500,
The degree of swelling of the filaments belonging to the second group (average thickness of the string-shaped body) is 5 mm.

This string-like material was dropped on a moving conveyor at a rate of 450 gr / m ² to form a curved shape and deposited, 1.5 wt% of saturated polyester resin powder was added as a binder, and the string was heated. The mats were combined to form a mat.

This mat has a thickness of about 5 times that of a mat having the same specifications, and the required amount of the binder used can be about 50%.

This mat is well impregnated with a liquid thermosetting resin, and is well suited to the mold. By using this mat as a reinforcing fiber body, it has a strong surface, a smooth surface, and FRP without delamination I was able to get it by the layup method.

An unsaturated polyester was used as the resin.

The amount of resin used was 70 wt% in FRP.

[Effects of the Invention] By using the resin-reinforcing fiber body, the thickness is large,
An FRP having a smooth surface and high strength can be obtained without causing delamination.

[Brief description of drawings]

FIG. 1 is an enlarged plan view for schematically explaining the structure of a cord-like body used in the present invention. In the figure, 1 is a cord-like body, 2 is a entangled portion, 3 is a section, f ₁ and f ₁ ′ are first group filaments, and f ₂ and f ₂ ′ are second group filaments.

Claims (1)

[Claims] 1. A reinforcing fiber body used for producing a fiber-reinforced resin body by impregnating a liquid thermoplastic resin and curing the resin, which is obtained by defibrating a bundle of a large number of filaments. In the body, the entangled portion in which the filaments forming the cord are entangled with each other is formed at a position spaced apart from each other, and the entangled portion divides the cord-shaped body into a plurality of sections. In, the string-shaped body includes a first group filament aligned in the longitudinal direction of the string-shaped body and a second group filament defibrated and swelled in a direction orthogonal to the longitudinal direction to form the string-shaped body. The filaments belonging to the first group of filaments in one section are arranged in the second section in other sections so that the total length of each filament becomes equal.
A resin-reinforcing fiber body comprising a mat formed of a string-like body belonging to a group filament or a cut product thereof.