JPH02131924A - Manufacture of latticed fiber reinforced plastic(frp) reinforcing member - Google Patents

Abstract

PURPOSE:To enhance the adhesion strength to material to be reinforced such as concrete or the like and consequently effectively reinforce said concrete or the like by a method wherein reinforcing fibers are braided in braided cords and, after that, assembled in a lattice and, finally, tension is applied to each braided cord under the state that the resin is melted so as to fill the interior of each braided cord with molten resin. CONSTITUTION:When reinforcing fiber bundle 10 is covered by thermoplastic resin, no impregnation at all or not much impregnation of resin in the fiber bundle is preferable, since the impregnation of the resin in the fiber bundle proportional impairs the flexibility of a composite 20. A braided cord 22 is produced by braiding the composite 20. In this case, dense braiding is preferably for favorable impregnation of resin in the following process. Next, the braided cords thus obtained are assembled in a lattice. At this time, each lattice point (intersecting point) is joined by entwining braided cords with each other. Next, the latticed assembly 24 is heated under tension or tension is applied to the assembly 24, the thermoplastic resin of which is put in molten state. By cooling the resin as tension is applied to the longitudinal and the lateral braided cords under the state that the thermoplastic resin is in molten state, the resin is solidified, resulting in obtaining latticed FRP formed body.

Description

Detailed Description of the Invention (Industrial Field of Application) This invention relates to a method for manufacturing a lattice-shaped FRP reinforcing member used for reinforcing cement, mortar, concrete, etc. This article relates to a method of manufacturing products using . (Prior Art) Conventionally, reinforcing bars have been welded and assembled into a lattice-like structure to reinforce concrete, etc. Reinforcing bars have a short lifespan due to corrosion problems, and for this reason, it has recently been considered that lattice-like reinforcing members can be made of FRP. By the way, this type of conventional lattice-shaped FRP reinforcing member uses thermosetting resin as the base resin, and is generally manufactured using the following methods.
That is, (a) FRP round bars are produced by pultrusion molding while continuously impregnating reinforcing fiber bundles with hardened thorns, and each round bar is arranged in a lattice shape as shown in Figure 5. Bind the 100 intersection points. A method of joining by adhesion, crossing, etc. (a) A method of impregnating reinforcing fiber bundles with resin before curing and placing them in a mold having a lattice-like cavity and curing them; (c) Method of impregnating reinforcing & MM bundles with hardened resin, assembling them in a lattice shape, and then curing them. (2) After assembling reinforcing fiber bundles in a lattice shape, impregnating them with uncured resin and then curing them. It was manufactured using methods such as (Problem to be solved by the invention) However, in the case of method (a) above, the lattice points (intersection points)
In addition, method (a) requires a mold, and the process of arranging each fiber bundle in the cavity is troublesome and difficult. Furthermore, in the case of method (c), since the resin impregnated into the reinforcing fiber bundles is sticky, there is a problem in that it is difficult to mechanically assemble the reinforcing fiber bundles into a lattice shape. Furthermore, in the case of method (2), the mia is easily damaged when the reinforcing fiber bundles are assembled into a lattice shape, and the lattice points (intersection points) are impregnated with resin after being assembled into a lattice shape. The problem is that the strength of the intersection points is low. (Means for Solving the Problems) The present invention has been made to solve the above problems, and the gist thereof is (a) to create a flexible material by combining continuous reinforcing fibers and thermoplastic resin. (a) a step of braiding the composite to produce a braid; and (c) a step of braiding the composite while intertwining the braid at lattice points after or simultaneously with the braiding. The process of assembling it into a shape (
2) heating the lattice-shaped assembled body to melt the thermoplastic resin; and (2) applying tension to each of the vertical and horizontal braids when at least the thermoplastic resin is in a molten state; and a step of cooling and solidifying the assembled body under tension to a temperature below the melting point of the thermoplastic resin. In this way, the present invention embroiders reinforced m#I to form braids, and after braiding the braids into a lattice shape, tension is applied to each braid under a resin melting state, and the inside of each braid is filled with the melted resin. This is how it was done.
In other words, the resin is not yet in a molten state at the stage of constructing the lattice-like assembled body, and therefore the lattice-like assembled body can be easily assembled and constructed without being hindered by the adhesiveness of the resin. The molding process is simple and easy since no molds are used during the solidification and molding stage, and the overall production of lattice-shaped FRP reinforcing members is possible at a high rate.
Furthermore, as described above, in the present invention, the resin is not impregnated after forming the lattice-like assembled body, but rather the pre-composite resin is melted after the lattice-like assembled body is formed. , In other words, the resin is injected into the braid in advance and melted to fill the gaps between the reinforcing fibers, so the resin sufficiently penetrates between each #am and strengthens each m fiber. 17ilR. Furthermore, for the same reason, the impregnation of resin at each lattice point is sufficient compared to the case where resin is impregnated after constructing the lattice-like assembled body, and therefore the strength of the intersection points is also increased. In addition, as a method of compositing reinforcing fiber and resin, if the outer surface of the reinforcing fiber is covered in a tube shape with a tree, even if the reinforcing fiber is easily damaged, the reinforcing fiber When braiding bundles into braided cords or when assembling braided cords in a lattice pattern, it is possible to avoid damage caused by rubbing of the fibers against each other. This is because each bundle is covered and protected by thermoplastic resin. In addition, since the lattice-shaped reinforcing member obtained by the present invention has irregularities on its outer surface, when it is used for reinforcing concrete, etc., it has a high adhesive strength with the reinforced material such as concrete, and such concrete, etc. Effectively reinforce. In the present invention, first, continuous reinforcing fibers and thermoplastic resin are combined to produce a flexible composite. Here, as the reinforcement am, all fibers used for conventional FRP, such as glass fiber, carbon fiber, 7-lamid lam. Alumina M fiber, silicon carbide fiber, etc. can be used.
In addition, as #a male east, any material that is mainly made of continuous fibers such as roving in which each single male is aligned in one direction, twisted yarn, bulky yarn, etc. can be used. When using a resin with poor impregnability, it is convenient to use a bulky yarn with good impregnability. On the other hand, resins include nylon resin, polypropylene resin, polyethylene resin, and polyphenylene sulfide resin. Various types of resin such as polyethylene terephthalate resin can be used, and they are selected as appropriate based on the required strength, heat resistance, corrosion resistance, etc. There are various methods for compositing reinforcing fibers and thermoplastic resins. For example, (a) the outside of the reinforcing fiber bundle may be covered with thermoplastic resin in a tube shape;
(b) The reinforced fiber bundle may be sprinkled with thermoplastic resin powder and then covered with thermoplastic resin from the outside in a tube shape. (C) Furthermore, reinforced fibers and thermoplastics! ! ! ! It may also be made into a composite by doubling it with +4 resin. Of these (7). In method (a), the reinforcing fiber bundles are covered and protected with resin, which is advantageous in that damage to the fibers can be prevented during the production of braided cords and lattice-like assembled bodies. In any case, the resulting composite must be flexible. Therefore, when covering a reinforcing fiber bundle with a thermoplastic resin, it is preferable not to impregnate the resin at all or to a small extent, since impregnating the inside of the fibers with the resin will impair the flexibility of the composite. In the present invention, the composite thus obtained is processed into a braided cord. In this case, it is better to braid the cord tightly in order to improve resin impregnation in the later process. Next, use the braid obtained in this way to assemble it into a lattice shape. At this time, each braid is tied together at the lattice points (intersection points) to connect them to each other. Various methods are possible for intertwining. In addition, when the reinforcing fibers are braided to form a braid, they may also be braided in a lattice pattern at the same time. Next, the lattice-shaped assembled body is heated while being stretched, or it is heated above the melting point of s1 to melt the thermoplastic resin, and then tension is applied to the assembled body. In this way, when tension is applied to the vertical and horizontal braids that make up the lattice-like assembled body while the resin is in a molten state, each braid contracts in the radial direction and the fibers that make up the braid approach each other. And they come into close contact with each other through natural plasticity. In other words, initially, the fibers were spread out in the radial direction to some extent, with gaps between them, but by applying tension to the braid, the fibers came closer together, and the resin became fully packed between them. becomes. Various heating methods are possible here, including hot air, radiation, and heat conduction. The viscosity of the resin is still high just above the melting point of the resin, so there is a risk that the resin will not be sufficiently impregnated into each m fiber, so it is generally heated to a temperature 20 to 100°C higher than the melting point. is desirable. In addition, if the tension that should be applied is too weak, the individual woven fibers will not be close enough to each other, and if it solidifies as it is, there is a risk that voids will be created inside the FRP molded product. Thickness and number of iam bundles. Select and adjust as appropriate depending on the ljA group system, etc. (for example, 500g to 10
kg). Now, the resin is melted vertically. When tension is applied to the horizontal braid and the resin is cooled to below the melting point of the resin, the resin solidifies and a lattice-shaped FRP molded body is obtained. The purpose of keeping each braid, that is, the lattice-like set L body in tension when cooling the resin, is to prevent the ams that are close to each other from being separated again due to tension, creating voids inside the FRP molded body. This is to prevent this. The FRP molded body obtained in this way has a certain degree of unevenness on its outer surface, so when it is used as a reinforcing member for concrete etc., the adhesive strength with concrete etc. is high,
Demonstrates excellent reinforcing effect. (Example) Next, in order to clarify the characteristics of the present invention, examples will be described in detail below. A glass fiber roving 10 (No. 11d (A)) of 575 tex with a thickness of 13 ALm is prepared, and its outer peripheral surface is
As shown in the figure, there is a tension adjuster 12, an extruder with a crosshead 14, and a take-off machine 4! ! 16. Using a to-be-received device equipped with a winder 18, a resin coating was applied so that the ratio of glass m fibers was 69% by weight ((B) in Fig. 1). This resin-coated reinforcing fiber bundle 20 is passed through a 16-piece braiding machine to a braided cord 22
((C) in Figure 1). Next, this braided cord 22 was assembled into a lattice shape with a lattice size of 1001 and a width W of 3501 as shown in FIG. 1(D) to obtain a assembled body 24. At this time, each braid 22 is connected at the intersection point in FIG. 3 (A
) to (D).
Of course, other methods of intertwining are also possible. Next, as shown in FIG. 4, the assembled body 24 was wound around a bobbin 26, and while being pulled out by a rubber roller 28, it was heated by a far infrared heater 30 in a heating sawn H, and then cooled in a cooling zone C. The tension in the vertical direction (drawing direction) on the two bodies 24 is applied to the bobbin 26 and the rubber roller 2.
81111 Te direction, horizontal direction (direction perpendicular to the pull-out direction)
The tension was performed using an appropriate tension generator 1&32. The tensile force at this time was 2 kg, the heating temperature was 280°C, and the drawing speed was 30 c+s/min. The lattice-shaped FRP reinforcing member obtained in this way has sufficient strength characteristics, is easier to mold than conventional FRP molded bodies using thermosetting resin, and has high efficiency. It can be manufactured in! Ta. Although the embodiments of the present invention have been described in detail above, the present invention can be implemented with various modifications based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram for explaining each step of a method for manufacturing a lattice-shaped FRP reinforcing member, which is an embodiment of the present invention, and FIG. 2 is a schematic diagram of a coating device used in the embodiment. It is. Fig. 3 is a diagram showing an example of a method of intertwining each braid at the intersection point in the same example, and Fig. 4 is a schematic diagram of the forming apparatus used in the same example. FIG. 5 is an explanatory diagram for explaining the defects of the conventional method. 1O: Glass fiber roving 20: Resin-coated reinforcing fiber bundle 22 Braided cord 24: Lattice-like assembled body FIG. 1 Patent applicant: Daido Steel Co., Ltd. Co., Ltd.

Claims (1)

[Claims] (a) A step of manufacturing a flexible composite by combining reinforcing continuous fibers and a thermoplastic resin; (b) A step of braiding the composite to manufacture a braided cord. (c) After the braiding process or simultaneously with the braiding process, assembling the braided cords in a lattice shape while intertwining them at lattice points, (d) heating the lattice-shaped assembled body to melt the thermoplastic resin. (e) vertically in a state where the thermoplastic resin is molten;
a step of applying tension to each horizontal braid to cause the braid to contract in the radial direction; and (f) a step of cooling and solidifying the braided body under tension to a temperature below the melting point of the thermoplastic resin. A method for manufacturing a lattice-shaped FRP reinforcing member, the method comprising: