JPH0415294B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a novel and hitherto unknown method for producing a fiber-reinforced resin body (FRP) obtained by defibrating a bundle of a large number of filaments. This invention relates to a string-like body for reinforcing resin.

[Prior Art] FRP is manufactured by impregnating a resin reinforcing string with a liquid thermosetting resin and curing the resin, and is widely used as pipes, bars, etc.

Pultrusion molding method, filament winding method (FW method), etc. are known as methods for producing FRP.

In order to obtain FRP with high strength and heat resistance,
It is necessary to use a material with high strength and heat resistance as the resin reinforcing string. Inorganic fibers such as glass fibers and alumina fibers are suitable fibers for this purpose, and among these, glass fibers are most widely used.

In the pultrusion molding method and the FW method, for the reasons described later, such resin reinforcing fibers are made of fiber bundles (fiber bundles) made by aligning and converging a large number of long monofilaments, preferably with the addition of a sizing agent. It is often used in the form of roving (strand) or a large number of strands arranged in a row.

[Problems to be Solved by the Invention] In the pultrusion molding method, a resin-reinforcing fiber body such as a fiber bundle impregnated with a liquid thermosetting resin is pulled through a mold having a predetermined cross-sectional shape, and heated during this process. to harden the resin.

In the FW method, a resin-impregnated reinforcing fiber body is wound under tension around a rotating mandrel without slack, and then the resin is cured.

In either method, when manufacturing FRP,
A fairly large tension is applied to the resin reinforcing fibers, and these resin reinforcing fibers are arranged adjacent to each other in parallel.

In the pultrusion molding method and the FW method, the resin reinforcing fibers are subjected to considerably large tensions, so the aforementioned fiber bundles with high tensile strength are used as the resin reinforcing fibers; Ta
Cracks may occur along the boundaries between adjacent parallel fiber bundles of FRP.

For this reason, in the pultrusion molding method, when a large number of fiber bundles impregnated with liquid thermosetting resin are arranged and fed to a mold, the outer peripheral part of the arrangement adjacent to the mold is used as a covering material like a pine. It has also been proposed to cover the pine with a mat, but this has the disadvantage that the pine is easily torn apart due to the frictional force with the mold during pultrusion molding.

In addition, fiber bundles are made up of fibers (monofilaments) that are bound together with a binding material.
The impregnation speed of liquid resin into the fiber bundle is slow, and FRP
Poor resin impregnation tends to occur in the interior.

By using bulky yarn obtained by defibrating fiber bundles, it is possible to improve resin impregnation and prevent the above-mentioned cracks, but bulky yarn is elongated when tension is applied. Therefore, bulky yarn cannot be used as a resin reinforcing fiber body in the pultrusion molding method or the FW method.

The present invention solves the problems of the prior art described above,
A resin reinforcing fiber that can be particularly suitably used as a resin reinforcing fiber body for pultrusion molding and FW methods, has high tensile strength, good resin impregnation, and does not cause cracks in the obtained FRP. The purpose is to provide a string-like body.

[Means for Solving the Problems] In order to achieve the above object, the resin reinforcing string-like body of the present invention is used in a state in which tension is applied to the resin reinforcing fibrous body using a pultrusion molding method, a FW method, etc. A string-like body obtained by defibrating a bundle of a large number of filaments, which is used in an FRP manufacturing method in which resin reinforcing fiber bodies are arranged in a aligned state, Intertwined portions are formed in which the filaments constituting the string-like object are intertwined at locations separated by intervals of the string-like object, and the string-like object is divided into multiple sections by these intertwined sections. The string-like body includes a first group of filaments aligned in the longitudinal direction of the string-like body and a second group of filaments that are unraveled and expanded in a direction perpendicular to the longitudinal direction, and constitute the string-like body. The filament is composed of a string-like body characterized in that the filament belongs to the first group of filaments in a certain section and belongs to the second group of filaments in another section so that the total length of each filament is equal.

Next, the present invention will be explained in more detail.

FIG. 1 is an enlarged plan view for schematically explaining the structure of a string-like body 1 used in the present invention, and the string-like body 1 is obtained by defibrating a bundle of many filaments, and Intertwined portions 2 are formed in which the filaments constituting the string-like object 1 are intertwined at spaced apart locations of the string-like object 1, and the string-like object 1 is divided into a plurality of sections 3 by the intertwined sections 2. , in each section 3, the string-like body 1 has a first group of filaments f1 aligned in the longitudinal direction of the string-like body 1, and a second group of filaments _f1 that are disentangled and expanded in a direction perpendicular to the longitudinal direction. ₂ , and the total length of each filament constituting the string-like body is equal, so that in one section, the filaments belonging to the first group of filaments are in the second group in other sections.
It is made to belong to the group filament.

The filaments that should constitute the string-like body include inorganic fibers such as glass fibers, alumina fibers, silica fibers, zirconia fibers, and titania fibers, organic fibers such as Kevlar fibers, metal fibers such as brass fibers, carbon fibers, Alternatively, conjugate fibers made by blending these can be used, but it is preferable to use glass fibers or conjugate fibers mainly composed of glass fibers.

The thickness of the fibers is suitably 3 to 30 μm, preferably 5 to 25 μm, and a sizing agent is added to these fibers and 50 to 100,000 fibers, preferably 200 to 50,000 fibers are arranged to form a fiber bundle. By shortening the residence time of the fiber bundle in the bulking device, such as bulking the fiber bundle while increasing the feeding speed to the bulking device, and making the air supply hole of the bulking device bulky. The string-like body of the present invention can be obtained by selecting bulking conditions such that the bulking conditions can be easily varied, such as opening the opening perpendicular to the tubular passage of the device.

When the air supply hole is opened obliquely to the tubular passage, the air blown from the air supply hole into the tubular passage flows in a fixed direction (fiber exit direction).
However, if the air supply hole is opened perpendicularly to the tubular passage, some of the air will also flow toward the fiber inlet, causing variations in the diameter of the fiber bundle. , due to the sway of the fiber bundle,
Due to changes in the relative positions of the fiber bundles at the entrance and exit of the tubular passage (for example, the fiber bundles are positioned in contact with the lower surface of the passage at the entrance, or are located at the center of the passage at the outlet), air flows out toward the outlet. There is a change in the ratio between the amount of air flowing out to the inlet direction, and the bulking conditions change.

Also, if the residence time in the bulking device is long,
Fluctuations in bulking conditions are easily averaged out, but if the residence time is short, averaging becomes difficult.

In addition, it is desirable that the drawing speed of the string-like body obtained by the method of the present invention is sufficiently lower than the feeding speed of the fiber bundle as a raw material so that bulking is performed under a low tension state.

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

As the sizing agent, it is preferable to use a material with low adhesive strength such as epoxy resin, and the amount added is 0.1 to 10 wt% as solid content, preferably 0.2
It is appropriate to set it to ~5wt%.

In the string-like body 1 of the present invention, intertwined portions 2, 2, . . . are formed in which the filaments constituting the string-like body are intertwined at locations separated by a predetermined interval in the longitudinal direction.

In the tangled portion 2, the filaments are monofilament-like or in a state in which several filaments are aligned and intertwined in a braid-like manner, and due to this intertwining, the filaments are slightly twisted.

By forming this entwined part 2, the string-like body 1
The filaments constituting the are bonded together so that they do not separate from each other.

The distance between the entangled portions 2 is suitably 1 to 30 mm, preferably 3 to 15 mm. If this length is too small, the proportion of the entangled portion 2 in the total length of the string-like body will be large, and the bulkiness of the string-like body 1 will be poor, resulting in insufficient cracking prevention effect and resin impregnation. Moreover, if this length is too large, the filaments of the first group and the filaments of the second group tend to separate.

The length of the entangled portion 2 is 0.1 to 5 mm, preferably
A suitable value is 0.2 to 3 mm. If this length is too large, the bulkiness of the string-like body 1 will be poor, and if this length is too small, the filaments constituting the string-like body 1 will easily separate.

The string-like body 1 is divided into a plurality of sections 3, 3... by the entangled portion 2.
divided into. In the section divided and sectioned by the intertwined portions 2, the string-like body 1 has a first group of filaments f1 aligned in the longitudinal direction of the string-like body and preferably twisted, and a filament _f1 , preferably monofilament-shaped. It includes a second group of filaments f ₂ which are opened into filaments and expanded in a direction perpendicular to the longitudinal direction. The filaments belonging to the second group are defibrated and swell outward in a substantially arc shape from the axis (longitudinal direction of the string-like body) connecting the entangled parts, and are preferably defibrated into a monofilament shape. Note that the direction of this bulge is not limited to a specific plane including the axis;
It's random. It is appropriate that the maximum distance of this bulge from the axis is about 2 to 10 mm.

The filaments belonging to the first group are aligned in the longitudinal direction. This filament is preferably S
The filaments belonging to the first group have good integrity due to the twist in the direction or Z direction.

When focusing on a specific section, the length of the filament _f1 belonging to the first group is the same as that of the filament belonging to the second group.
When tension is applied to the string-like body, filament f ₁ , which is shorter than the length of f ₂ and belongs to the first group, counteracts the 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 itself counteract the tension, but this filament f ₂ belongs to the first group. The filament f ₁ and the entwined part 2 are intertwined, and the tension applied to the string-like body 1 is absorbed by the filament f ₁ belonging to the first group, so even if tension is applied to the string-like body 1, the tension in this section is The length does not substantially extend beyond the length of the filament f ₁ belonging to the first group, and the second
The filament f ₂ belonging to the group is not stretched and loses its bulkiness.

It is appropriate that the number of filaments belonging to the first group is 10 to 50% of the total number of filaments. If this number is too large, the bulkiness of the string-like body 1 will be poor, and if this number is too small, the strength in the longitudinal direction of the string-like body 1 will tend to decrease.

When focusing on a specific section, the filament _f1 , indicated by the broken line belonging to the first group, and the filament _f2 , indicated by the solid line belonging to the second group, are intertwined and confused at the tangled part at the end of this section. In the next section, the filament f ₁ ' belongs to the first group and the filament f ₂ ' belongs to the second group.

At this time, at least part of f ₁ or f ₂ ' is transferred to the second
At least a part of f ₂ transfers to f ₁ ' and belongs to the first group. This kind of transition to a different group (change of affiliation) is done randomly, but when focusing on a certain filament, the number of times this filament belongs to the first group and the number of times it belongs to the second group in each section are approximately the same. and the total length of each filament making up the string-like body is equal.

Note that the direction of twist given to the filaments of the first group is reversed in some places, and the number of twists in the S direction and the number of twists in the Z direction are approximately equal in the string-like body as a whole, causing twisting in the string-like body. Never.

A reversal of the twist direction may also occur within a section, in which case a small length of untwisted portion may occur in this reversal.

Note that the filaments belonging to the first group may swell slightly outward at such inverted portions, but this swell is extremely small compared to the swell of the filaments of the second group, and is similar to the above-mentioned string-like filaments. It does not affect the countervailing force to the tension applied to the body.

In addition, the length of the tangled part, the distance between the tangled parts, the number of filaments belonging to the first group in each section,
It is practically meaningless to control the degree of swelling of the filaments belonging to the second group to a constant value over the entire length of the string-like body, and the purpose of the present invention can be sufficiently achieved by keeping these within the above-mentioned range. can be achieved.

Furthermore, the string-like body for reinforcing the resin of the present invention is made of glass fiber,
It can be composed of relatively soft fibers such as organic fibers, but it can also be composed of brittle fibers such as silica fibers, and such string-like bodies do not lose bulk even when tension is applied, and are large. Has heat resistance.

Such a string-like body has a first group of filaments that are aligned in the longitudinal direction of the string-like body, so the tensile tension is large, and a second group of filaments that are opened and expanded in a direction perpendicular to the longitudinal direction of the string-like body are large. Therefore, it has good impregnability with liquid resin, and when a plurality of these string-like bodies are arranged in parallel, the second group filaments of adjacent string-like bodies become intertwined, so this string-like body is used for resin reinforcement. used as a fibrous body
Since cracks do not occur along the boundaries between the string-like bodies in FRP, the resin-reinforcing string-like body of the present invention is particularly useful as a resin-reinforcing fiber body for the pultrusion molding method and the FW method.

In addition, the type of liquid thermosetting resin used for manufacturing FRP by the pultrusion molding method or the FW method using the resin reinforcing string-like body of the present invention, and the amount of the resin added to the string-like body , the application method, the molding method, etc., are no different from commonly used methods, so detailed explanations will be omitted.

[Operation] A string-like body is formed by defibrating a bundle of a large number of filaments, and entangled portions where the filaments constituting the string-like body are entangled are formed at spaced apart locations of the string-like body. The string-like body is divided into a plurality of sections by this intertwined part, and in each section, the string-like body is divided into a first section aligned in the longitudinal direction of the string-like body.
A filament that belongs to the first group filament in a certain section such that the total length of each filament constituting the string-like body is equal, including a group filament and a second group filament that has been opened and expanded in a direction perpendicular to the longitudinal direction. By making the filaments belong to the second group in other sections, the impregnating property of the liquid resin is improved without reducing the tensile strength, and the filaments belonging to the second group are entangled to make this string-like body To prevent cracks from occurring in FRP along the boundary surface between a plurality of parallel string-like bodies and adjacent string-like bodies when used as a resin reinforcing fiber body.

[Example 1] 0.2wt% of epoxy sizing agent was added as a solid content to glass fiber (filament) with a thickness of 9μ.
Using the fiber bundle formed by this convergence, an air processing machine AT-501 manufactured by Aiki Seisakusho Co., Ltd., equipped with an air supply hole opened perpendicular to the tubular passage, was used to produce a string-like material with the following specifications. was manufactured.

The fiber bundle supply speed is 120 m/sec, the withdrawal speed is 110 m/sec, and the average pressure of compressed air is 5.0
Kg/cm ² G.

Specifications of the string-like body Average length of entangled parts 3 mm, average distance between entangled parts 8 mm, average number of filaments belonging to the first group 1500, degree of swelling of filaments belonging to the second group ( Average thickness of string-like body) 5
mm.

Add unsaturated polyester resin to this string-like body,
Using FRP impregnated with a resin amount of 35 wt%, a pipe was manufactured by the FW method according to a conventional method.

This pipe has the same strength as that using ordinary roving, has good resin impregnation, does not produce defective products due to poor resin impregnation, and has a smooth surface. , and no surface cracks were generated.

[Example 2] The same results as in Example 1 were obtained by using the string-like body of Example 1 as a resin reinforcing fiber body in a pultrusion molding method.

[Effects of the invention] It has a large tensile strength and good impregnability with liquid resin, and by using this string-like body as a resin-reinforcing fiber body, it is possible to prevent cracks from occurring in FRP and improve the surface smoothness. It is possible to obtain FRP with high strength.

[Brief explanation of drawings]

FIG. 1 is an enlarged plan view for schematically explaining the structure of the string-like body of the present invention. In the figure, 1 is a string-like body, 2 is a tangled part, 3 is a section, f ₁ ,
f ₁ ' represents the first group filament, and f ₂ and f ₂ ' represent the second group filament.

Claims (1)

[Claims] 1 A string-like body obtained by defibrating a bundle of a large number of filaments, in which tangled portions are formed where the filaments constituting the string-like body are intertwined at spaces apart from each other. The string-like body is divided into a plurality of sections by this entwined part, and in each section, the string-like body is separated from the first group of filaments that are aligned in the longitudinal direction of the string-like body, and is unraveled and separated in the longitudinal direction. and a second group filament expanding in a direction perpendicular to the filament, and the filaments belonging to the first group filament in one section become the second group filament in another section so that the total length of each filament constituting the string-like body is equal. A string-like body for resin reinforcement characterized by the fact that