JP6762503B2 - One-way reinforced fiber sheet - Google Patents

Description

The present invention relates to a reinforced fiber sheet used for molding fiber reinforced plastics and reinforcing wood materials and the like.

Fiber reinforced plastics made of reinforced fibers with high strength and high elastic modulus, such as carbon fiber, are widely used as structural materials for sports equipment and aircraft because of their light weight and excellent mechanical properties.

As a reinforcing sheet used for molding fiber reinforced plastics, there are dry preforms in which reinforcing fibers are integrated into a sheet with woven fabric or adhesive, and repairs such as large molded products, molded products with complicated shapes, concrete and building materials. , Or is used for various purposes such as reinforcement.

Among the dry preforms, the unidirectional sheet in which the reinforcing fibers are aligned in one direction to form a sheet is often used because the high strength and high elastic modulus of the reinforcing fibers are maximized. For example, in Patent Document 1, A unidirectional sheet has been proposed in which a heat-sealing non-woven fabric is laminated on one side of a sheet-like material in which fiber threads are aligned in one direction and integrated.

In the case of the base material proposed in Patent Document 1, high strength characteristics are expected because the reinforcing fibers are integrated in a state of being arranged in one direction, but when laminated, they are layered or on the surface. Since the non-woven fabric is present, there is a concern that the interlayer strength is lowered and the surface quality is deteriorated, and there is a problem that the range of use is limited. Further, when the reinforcing fibers are aligned in one direction, the reinforcing fibers are in a close-packed state, and the impregnation property of the resin is lowered, so that there is a problem that it takes time to impregnate the resin.

Further, as a technique for integrating a unidirectional reinforcing fiber sheet, in Patent Document 2, thin auxiliary fibers are placed on the front and back of a reinforcing fiber sheet-like material in which a plurality of reinforcing fibers are arranged in parallel in one direction at right angles to the reinforcing fibers. A unidirectional sheet that is aligned and fixed in the direction and integrated has been proposed, and since auxiliary fibers are linearly present on the front and back surfaces, there is almost no effect on the interlayer strength, but on the surface of the molded product. Since the auxiliary fibers are raised, surface polishing work is required for molded products that require surface smoothness, and resin impregnation has the same problems as in Patent Document 1.

As a technique for improving the resin impregnation property in a unidirectional reinforcing fiber sheet, for example, in Patent Document 3, a plurality of reinforcing fiber bundles covered with covering threads of low melting point fibers are arranged in parallel in the longitudinal direction. A reinforcing fiber sheet has been proposed in which fiber strand bundles in which covering threads are adjacent to each other are fused by heat-bonding, and each reinforcing fiber bundle is bundled. Is flowed as a resin path, but since the reinforcing fiber bundle is firmly bundled by the covering yarn, there is a drawback that it takes time to impregnate the inside of the fiber bundle, and the melt of the covering yarn is formed on the surface of the molded product. There are also remaining problems.

Japanese Unexamined Patent Publication No. 2000-198158 Japanese Unexamined Patent Publication No. 2010-156081 Japanese Unexamined Patent Publication No. 2014-046618

An object of the present invention is to provide a fiber reinforced plastic as a composite reinforcing fiber base material, which does not disturb the fiber orientation and has excellent handleability and resin impregnation property, and exhibits high mechanical properties and surface quality. It is in.

The means adopted by the present inventor to solve the above technical problems will be described as follows with reference to the accompanying drawings.

That is, in the unidirectional reinforcing fiber sheet of the present invention, a plurality of reinforcing fibers are parallel in one direction, and ^two thin sheets having a basis weight of 10 to 50 g / m ² are overlapped in the same direction, and the two thin sheets are thin. It was completed by arranging the thermoplastic resins in dots or lines between the sheets and integrating them.

Further, as the unidirectional reinforcing fiber sheet of the present invention, it is possible to adopt a technical means in which one or a plurality of linear thermoplastic resins are arranged in a zigzag shape in the length direction.

Further, the unidirectional reinforcing fiber sheet of the present invention employs a technical means in which one or a plurality of auxiliary threads are arranged in a zigzag shape in the length direction between the two thin sheets. Can be done.

Furthermore, it is possible to adopt a technical means in which the linearly arranged thermoplastic resin is made of a thermoplastic resin adhering around the auxiliary thread.

Furthermore, as the thermoplastic resin, a technical means in which a fiber yarn made of a low melting point polymer having a melting point of 180 ° C. or less is thermally melted can be adopted.

Furthermore, technical means can be adopted in which the weight per length of the linearly arranged thermoplastic resin is in the range of 5 to 25 g / 1000 m.

Furthermore, technical means in which the reinforcing fiber is a carbon fiber can be adopted.

In the unidirectional reinforcing fiber sheet of the present invention, two thin sheets having a grain size of 10 to 50 g / m ² in which a plurality of reinforcing fibers are parallel in one direction are overlapped in the same direction, and between the two thin sheets. Since the thermoplastic resin is arranged in a dot or linear shape and integrated, it is possible to adhere to the fibers on the surface of the unidirectional reinforcing fiber sheet material, and further between each reinforcing fiber and two thin sheets. Due to the presence of the resin passage path between the sheets, the resin impregnation property is excellent, and the molding time can be shortened and the molded product of the voidless can be made.

In addition, by arranging the thermoplastic resin or auxiliary thread for integration between the two sheets, the thermoplastic resin and auxiliary thread will not come off even if the surface of the base material is scratched or heated. In addition, since there is no thermoplastic resin or auxiliary thread on the surface, the surface of the molded product can be finished cleanly and smoothly.

Further, even in the case of laminating between reinforcing fiber sheets or laminating with wood or the like, since there is no auxiliary thread on the laminated surface, the reinforcing fibers come into contact with the surface to be reinforced in a straight state, and a high reinforcing effect is exhibited.

Further, by optimizing the amount of the thermoplastic resin, it is possible to exert both the effects of sufficient integration by adhesion and the suppression of the protrusion of the thermoplastic resin on the surface of the unidirectional reinforcing fiber sheet.

It is a perspective view of the unidirectional reinforcing fiber sheet of 1st Embodiment of this invention. It is a perspective view of the unidirectional reinforcing fiber sheet of the 2nd Embodiment of this invention. It is a perspective view of the unidirectional reinforcing fiber sheet of the 3rd Embodiment of this invention.

The embodiment for carrying out the present invention will be described in more detail based on the specifically illustrated drawings as follows.

<First Embodiment>
The first embodiment of the present invention will be described with reference to FIG. Reference numeral 1 is a unidirectional reinforcing fiber sheet of the present invention, in which the front side sheet 2 in which a plurality of reinforcing fibers are parallel in one direction and the back side sheet 3 are overlapped in the same direction, and the two sheets 2 and 3 are overlapped. A plurality of linear thermoplastic resins 4 are arranged in a zigzag shape in the length direction between them, and since the linear thermoplastic resins 4 are continuously present in the width direction, the sheets 2 and 3 are adjacent to each other. The reinforcing fibers are bonded to each other and between the sheets 2 and 3 to ensure reliable integration.

In the method of arranging the thermoplastic resin 4 in a zigzag linear shape, for example, two sheets 2 and 3 are supplied from different angles to the nip portion of a pair of heating rollers, and a fiber made of a low melting point polymer is supplied from the front of the nip portion. The thermoplastic resin 4 can be arranged in a zigzag shape between the two thin sheets 2 and 3 by supplying the threads while repeatedly swinging them in the width direction and heat-bonding them with a heating roller.

Although FIG. 1 shows an example in which the thermoplastic resins 4 are arranged in a plurality of linear shapes, they may be arranged in a zigzag shape over the entire width in a single linear shape. However, it is preferable to reduce the swing width in the width direction with a large number of pieces because the production speed can be increased and the manufacturing cost becomes low.

Examples of the reinforcing fibers used in the unidirectional reinforcing fiber sheet 1 of the present invention include high-strength and high elastic modulus fibers such as carbon fiber, glass fiber, and aramid fiber. Among them, the tensile strength is 4 GPa or more and the tensile elastic modulus is 200 GPa. The above carbon fibers are suitable because they exhibit high specific strength and specific elastic modulus, and as the yarn fineness of the carbon fibers, a thick fineness yarn of 500 Dtex or more, which is relatively inexpensive to manufacture, is preferable. Further, by expanding the carbon fiber yarn of the thick fineness yarn into a thin sheet by the opening and widening step, a gap is generated between the carbon fibers, and the sheet becomes a resin passage when the resin is impregnated and is easily impregnated with the resin.

The basis weight of the reinforcing fibers of the front side sheet 2 and the back side sheet 3 of the unidirectional reinforcing sheet 1 of the present invention is 10 to 50 g / m ^{2, which} is a very thinly opened sheet, and the sheet 2 or If the basis weight of 3 is less than 10 g / m ² and the basis weight is low, there is no problem with impregnation, but since the reinforcing fiber amount is small and the reinforcing effect is insufficient, the basis weight is preferably 10 g / m ² or more. If it exceeds 50 g / m ² , the resin impregnation property is lowered and some kind of forced impregnation operation is required. Therefore, the basis weight of the reinforcing fibers is preferably 50 g / m ² or less.

Further, in the unidirectional reinforcing fiber sheet 1 of the present invention, since the two sheets 2 and 3 are stacked and the thermoplastic resin 4 exists between the two sheets 2 and 3, the two sheets 2 and 3 are present. Since there is a gap between them that serves as a resin passage, the impregnation property does not deteriorate even if two sheets are overlapped and the basis weight is doubled.

Further, as the thermoplastic resin 4 used for the unidirectional reinforcing fiber sheet 1 of the present invention, a thermoplastic polymer such as nylon, copolymerized nylon, polyester, vinylidene chloride, vinyl chloride, or polyurethane can be used. Of these, copolymerized nylon is preferable from the viewpoint of adhesiveness to the molding resin. Further, the melting point of the thermoplastic resin is preferably as low as 180 ° C. or lower, and by using a thermoplastic resin having such a low melting point, the thermal bonding process can be speeded up and the manufacturing cost can be reduced.

In the case where the thermoplastic resin 4 is arranged linearly, the weight per length of the linear thermoplastic resin 4 is preferably in the range of 5 to 25 g / 1000 m, and the weight per length of the thermoplastic resin 4 is preferable. If the weight is less than 5/1000 m, the adhesive force that integrates the two thin sheets 2 and 3 is weak and the sheet material is difficult to handle. On the other hand, if the weight exceeds 25 g / 1000 m, the thermoplastic resin 4 is melted. The thermoplastic resin 4 exudes to the surface of the directional reinforcing fiber sheet 1, and the weight per length of the linear thermoplastic resin 4 is 5 due to adverse effects such as deterioration of the appearance of the sheet material and stains on the heating roller in the manufacturing process. A range of ~ 25 g / 1000 m is suitable.

<Second Embodiment>
FIG. 2 shows the unidirectional reinforcing fiber sheet 1 of the second embodiment of the present invention, in which the thermoplastic resin is arranged in dots between the two thin sheets 2 and 3, and the two thin sheets 2 and 3 are arranged. Are bonded and integrated, and as in the first embodiment, a gap that serves as a resin passage is formed between the two sheets 2 and 3, so that the impregnation property is lowered even if the two sheets are overlapped and the basis weight is doubled. There is no such thing.

As a method of arranging the two sheets 2 and 3 in a dot pattern, for example, a thermoplastic resin powder is sprayed on either side of the two sheets 2 and 3, and another sheet is placed on the surface. It can be integrated by stacking and thermocompression bonding at a temperature equal to or higher than the melting point of the thermoplastic resin 4. If the amount of powder used for arranging the thermoplastic resin 4 in dots is about 1 to 4% with respect to the weight of the powder reinforcing fiber having an average particle size of about 5 to 20 μm, the unidirectional reinforcing fiber sheet 1 at the time of heat melting There is no exudation on the surface of the plastic, and a sufficient adhesive effect can be obtained.

<Third Embodiment>
FIG. 3 shows a unidirectional reinforcing fiber sheet 1 according to a third embodiment of the present invention, in which one or a plurality of auxiliary threads 5 are arranged in a zigzag shape in the length direction between two thin sheets. Is. By interposing the auxiliary thread 5, the strength of the unidirectional reinforcing fiber sheet 1 in the width direction can be obtained, and the unidirectional reinforcing fiber sheet 1 can be torn even if an external force is applied in the width direction during molding work or the like. Such troubles can be prevented.

The type of the auxiliary yarn 5 is not particularly limited, but is preferably a fiber yarn having a small heat shrinkage when the thermoplastic resin 4 is heated to a melting temperature or higher, for example, a glass fiber yarn, a carbon fiber yarn, or an aramid fiber yarn. Among them, glass fiber yarns are preferable because they have almost no heat shrinkage and fine fineness yarns can be obtained at low cost.

Since the auxiliary thread 5 is intended to strengthen the integration, it does not require much strength, and the thread fineness of the auxiliary thread 5 is 700 Dtex or less, and can be shaken in the width direction. It is preferable to arrange them at a coarse density with an interval of about 1 to 5 cm in the length direction so that the amount used is small.

Further, FIG. 3 shows an example in which the zigzag arrangement of the auxiliary thread 5 and the zigzag arrangement of the thermoplastic resin 4 are synchronized, and as a method of synchronizing in such a manner, for example, the auxiliary thread 5 is used as a core. A covering method in which a low melting point polymer thread made of a thermoplastic resin is wound around, or an auxiliary thread 5 in which a low melting point polymer is attached around the auxiliary thread 5 using an extrusion molding machine, two thin sheets 2 and 3 By heat-pressing from both sides of the combined thin sheets 2 and 3 at a temperature higher than the melting temperature of the low melting point polymer, the low melting point polymer adhering around the auxiliary thread 5 is formed on the two thin sheets 2 -By adhering to the inner surface of 3, the thermoplastic resin 4 can be arranged along the auxiliary thread 5.

FIG. 3 shows an example in which the zigzag arrangement of the auxiliary threads 5 and the zigzag linear arrangement of the thermoplastic resin 4 are matched, but the point-like arrangement of the thermoplastic resin 4 shown in the second embodiment is shown. The auxiliary threads 5 may be arranged in a zigzag shape on the directional reinforcing fiber sheet 1, and the auxiliary threads 5 may be arranged in a locus different from the zigzag locus of the linear arrangement of the thermoplastic resin 4 shown in the first embodiment. It may be arranged in a zigzag shape.

Although the present invention is generally configured as described above, the present invention is not limited to the illustrated embodiment, and various modifications can be made within the description of "Claims".

1 One-way reinforced fiber sheet material 2 (front side) sheet 3 (back side) sheet 4 Thermoplastic resin 5 Auxiliary thread

Claims (7)

Multiple reinforcing fibers are parallel in one direction, ^two thin sheets with a basis weight of 10 to 50 g / m ² overlap in the same direction, and the thermoplastic resin is dotted or linear between the two thin sheets. A unidirectional reinforced fiber sheet characterized by being placed and integrated in. The unidirectional reinforcing fiber sheet according to claim 1, wherein one or a plurality of linear thermoplastic resins are arranged in a zigzag shape in the length direction. The unidirectional reinforcing fiber sheet according to claim 1 or 2, wherein one or a plurality of auxiliary threads are arranged in a zigzag shape in the length direction between the two thin sheets. The unidirectional reinforcing fiber sheet according to claim 3, wherein the linearly arranged thermoplastic resin is made of a thermoplastic resin adhering around the auxiliary thread. The unidirectional reinforcing fiber sheet according to any one of claims 1 to 4, wherein the thermoplastic resin is a low melting point polymer having a melting point of 180 ° C. or lower. The unidirectional reinforcing fiber sheet according to any one of claims 1 to 5, wherein the weight per length of the linearly arranged thermoplastic resin is in the range of 5 to 25 g / 1000 m. The unidirectional reinforcing fiber sheet according to any one of claims 1 to 6, wherein the reinforcing fiber is a carbon fiber.