JPH0572434U - Fiber reinforced plastic tube - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to reduce the weight and improve bending strength and compressive strength. Furthermore, it can be formed by pultrusion molding like conventional FRP pipes.
Allows molding at low cost. [Structure] As a reinforcing material, a seamless tubular woven fabric having a plurality of layers having different fiber densities in the thickness direction, at least the inner and outer layers 2 and 3 having a high fiber density, and the intermediate layer 4 having a low fiber density A multilayer tubular cloth which is a cloth is used.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high-strength, high-rigidity fiber-reinforced plastic pipe that can be used as a buried pipe.

[0002]

[Prior Art]

 Normally, earth pipes and iron pipes are used as buried pipes, but these are very heavy and have poor workability in transportation, burial, removal, etc., so recently, fiber-reinforced plastic pipes with excellent strength and light weight ( (Hereinafter referred to as FRP tube) has come to be used.

[0003]

[Problems to be solved by the device]

 However, as described above, the conventional FRP pipe has excellent properties such as high bending strength and general strength such as compression strength and light weight, but has a drawback of low rigidity. was there. Therefore, when this FRP pipe is used as a buried pipe, there is a problem that it is bent due to earth pressure or the like. On the other hand, as disclosed in Japanese Examined Patent Publication No. 48-37139, a reinforced plastic pipe in which the inner and outer layers are made of FRP and the middle layer is made of resin concrete is also proposed. Since resin concrete is interposed between the inner and outer layers, it requires a special method and equipment to manufacture it, and by using resin concrete, the weight is larger than that of FRP only. There was also the problem of becoming. Furthermore, in the case of this conventional FRP tube, since the FRP reinforcing fibers of the inner and outer layers are wound and laminated in a spiral shape, the fiber orientation has an angle with respect to the axis, which is ideal for compression resistance. The fiber orientation does not occur, and it cannot be said to be advantageous in strength.

The present invention has been made in view of the above, and it is possible to reduce the weight as compared with a conventional FRP tube using a resin concrete for the intermediate layer, and to substantially reduce the fiber orientation. Provided is an FRP tube that can be formed at right angles to the axial direction, improve compression rigidity, and can be formed by pultrusion molding so that it can be formed at low cost without using a special forming method. It is characterized by doing.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the FRP pipe according to the present invention is a seamless tubular woven fabric having a plurality of layers having different fiber densities in the thickness direction as a reinforcing material, and at least the inner and outer layers having a high fiber density. The intermediate layer is a multilayered tubular cloth having a low fiber density.

[0006]

[Work]

 In the FRP pipe having the above-mentioned structure, the reinforcing material is impregnated with plastic and is drawn and molded. At this time, the fiber density of the inner and outer layers is high and the fiber density of the intermediate layer is low, and the bending load in the inner and outer layers is increased. , Receives a compressive load and imparts rigidity to the intermediate layer.

[0007]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. In the figure, 1 is an FRP tube, and the reinforcing fiber of this FRP tube uses a seamless tubular fabric for the inner and outer layers and a tubular fabric for the intermediate layer, and as shown in FIG. The inner and outer layers 2 and 3 have a high fiber density, and the intermediate layer 4 has a low fiber density. Then, the same plastic is impregnated as a matrix in each of the layers 2, 3 and 4 and is integrally molded. The above seamless woven fabric may be used by being woven integrally with each layer, or each layer may be laminated while being sequentially drawn. By using a tubular weave as the seamless woven fabric, the fiber orientation with respect to the axis becomes substantially perpendicular, and the ideal fiber orientation is taken with respect to compression resistance. FIG. 3 schematically shows an enlarged cross section of the outer layer 3, in which the plastics 5 are impregnated between the fibers of the seamless fabric.

FIG. 4 shows how the FRP pipe is pultruded, and a seamless woven fabric 8 serving as a reinforcing fiber is inserted into one of the pultrusion molding machine 7 having the heater 6 and the pultrusion molding is performed. While being impregnated with the thermosetting plastic injected from the plastic injection port 9 provided in the machine 7, it is drawn and molded by a mold not shown, and then cured by the heater 6. In this molding, the seamless woven fabric 8 may be impregnated with plastic before being introduced into the pultrusion molding machine 7. Further, as the above plastic, a thermosetting one is generally used, but a thermoplastic one may be used, and in this case, it is called FRTP. This FRTP molding method is essentially the same as the general thermoplastic molding method. As the material of the above-mentioned strength fiber, glass fiber is generally used, but in addition, inorganic fiber such as carbon or organic fiber such as aramid is used.

In each of the layers used as the reinforcing fibers, the inner and outer layers having high fiber density have, in addition to the structure shown in FIG. 3, thin warp yarns 10 and weft yarns 11 made of thick roving as shown in FIG. The yarn 12 is connected to each other, and the fiber density of this layer is adjusted by the distance between the warp and the weft. The intermediate layer having a low fiber density is, for example, as shown in FIG. 6, and has a structure in which a warp yarn 13 made of bulky yarn and a weft yarn 14 made of bulky yarn are entwined in a wave shape.

As described above, by using the seamless tubular woven fabric as the reinforcing material for the inner and outer layers, it is easy to draw and form, and the formed pipe is less likely to crack. In addition, as variations of the cloth for the intermediate layer, there are (a) a woven fabric composed of warp yarns and weft yarns, (b) a knitted fabric, and (c) a non-woven fabric. In the case of the above (a), the intermediate layer also has a bending load and a compressive strength. To some extent, (b) has bulkiness and is easy to earn thickness, and (c) has bulkiness and is easily impregnated with resin, which is generally lower in cost than woven or knitted fabrics. There are some advantages. Further, as variations of the tubular structure of the intermediate layer, (d) a seamless tubular shape is prepared in advance, (e) a sheet-like cloth is formed into a tubular shape by combining both edges thereof, and (f) a tape-like cloth is spirally formed. In the case of (d) above, there is no seam and cracks do not occur from there. In the case of (e), it is easy to form a tubular shape in the case of a non-woven fabric, and bending is less likely to cause cracks when a load is applied, and in the case of (f), cracks are less likely to occur at the time of compressive load. Further, variations of the raw yarn used include (g) roving, yarn, (h) bulky yarn, (i) roving or yarn for inner and outer layers, or a combination thereof. In the case of the above (g), high strength is obtained. In the case of (h), a pipe can be easily obtained, and in the case of (h), the thickness can be easily obtained, and the resin impregnating property and penetrating property are good. In the case of (i), the use of bulky yarn in the intermediate layer makes it easier to obtain a pipe that is more resistant to bending loads and compression loads and has high rigidity. Further, as a variation of the multilayer structure, (j) a multilayer integrally woven fabric in which the inner, middle and outer layers are bonded to each other, (k), the inner, middle and outer layers each having a larger diameter in order. In the case of the above (j), each layer is connected by a thread at the time of weaving, so that a pipe having a high interlayer strength and a higher strength can be obtained. A loom capable of special multiple weaving is required. In the case of (k), it is possible to weave with a general loom, but the length is limited because it is pulled in. As a variation of the above-mentioned multilayer, (m) a circular loom is used, the inner layer side is used as a core and the outer layer side is woven on it, (n) an inner layer or outer layer is woven with an intermediate layer, However, in the case of the above (m), a long product can be easily obtained, which is particularly suitable for continuous molding such as pultrusion, and the gap between layers is small and cracking is small. In the case of (n), the layers in which the fiber density greatly changes are woven together, and cracks due to shearing are unlikely to occur.

Next, the FRP pipe of the embodiment of the present invention and the FRP pipe using resin concrete as the intermediate layer were made to have an outer diameter of 120 mm and a wall thickness of 10 mm, respectively, and the results of comparison of their performances are shown in Table 1. Shown in. The FRP pipe of the embodiment of the present invention was formed by pultrusion using a seamless woven fabric using glass fiber and epoxy resin, and resin concrete was used as an intermediate layer. Polyester was used.

[0012]

[Table 1]

As shown in Table 1 above, the FRP pipe according to the embodiment of the present invention has a smaller specific gravity and a lighter weight as compared with the conventional FRP in which the intermediate layer is made of resin concrete, and the bending strength and the compression strength are also reduced. Was about twice as large. Further, in the FRP tube according to the present invention, by using the seamless woven fabric as the strength fiber, the orientation of the weft yarn with respect to the axis of the FRP pipe is substantially 90 degrees, and the compressive load resistance by the weft yarn becomes maximum. The compressive strength is improved as compared with the case where the weft threads are inclined with respect to the warp threads.

[0014]

[Effect of the device]

 According to the present invention, the bending load and the compression load are supported by the outer layers 2 and 3 having a high fiber density, and the rigidity is imparted by the intermediate layer 3 having a low fiber density. Compared to conventional FRP using concrete, it is possible to reduce the weight and improve bending strength and compressive strength. Furthermore, as with conventional FRP pipes, it can be formed by pultrusion. It can be molded at low cost without using a special molding method.

[Brief description of drawings]

FIG. 1 is a perspective view showing a fiber reinforced plastic tube.

FIG. 2 is an enlarged cross-sectional view of a fiber reinforced plastic pipe.

FIG. 3 is an enlarged cross-sectional view of an outer layer portion of a fiber reinforced plastic pipe.

FIG. 4 is an explanatory view showing a state of pultrusion molding of an FRP pipe.

FIG. 5 is a schematic configuration explanatory view of a portion of the reinforcing fiber having a high fiber density.

FIG. 6 is a schematic configuration explanatory view of a portion of the reinforcing fiber having a low fiber density.

[Explanation of symbols]

1 ... Fiber reinforced plastic tube, 2, 3 ... Inner, outer layer, 4 ...
Intermediate layer, 5 ... Plastic, 6 ... Heater, 7 ... Pultrusion molding machine, 8 ... Seamless fabric, 9 ... Plastic injection port.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location // B29K 105: 08 B29L 23:22 4F (72) Inventor Masao Kikuchi 3-Aobadai, Meguro-ku, Tokyo 10-9 Komatsu Kasei Co., Ltd. (72) Inventor Izumi Taniguchi 34-305, Inouchi Minamiuchihata, Nagaokakyo-shi, Kyoto (72) Inventor, Kazutaka Esaki 2-12-1, Shibahara-cho, Toyonaka-shi, Osaka

Claims (1)

[Scope of utility model registration request] 1. A reinforcing material comprising a plurality of layers having different fiber densities in the thickness direction, and at least the inner layers 2 and 3 are seamless tubular fabrics having a high fiber density, and the intermediate layer 4 is a low fiber density. A fiber-reinforced plastic tube characterized by using a multilayered tubular cloth which is a tubular cloth.