JPS6349622B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing FRP pipes, and more particularly, to a method for manufacturing high-quality FRP pipes with high productivity. Conventional methods for producing FRP pipes include two methods: roving is impregnated in a resin bath, then wrapped around a core mold, and after hardening, the core mold is removed from the mold.The other method is to prepare prepregs in which roving is impregnated with resin in advance. There are two main methods: wrapping the resin around a core mold, completely curing the resin, and removing the core mold. However, with this method, more resin than required adheres to the roving during the impregnation process, so it is necessary to collect the excess resin during winding and return it to the resin bath for cyclic use. Not practical. Therefore, it takes a long time to harden, especially for thick FRP.
In the case of pipes, productivity is extremely poor. In addition, a method of using a squeegee roller, etc. to adjust the amount of resin in the impregnation process has been implemented, but the resin hardens at the roller part and the impregnation rate fluctuates, and in some cases, the hardened resin may cause It may also be impossible to feed the roving. Therefore, especially in the continuous molding of FRP pipes, the squeegee roller and ancillary equipment must be frequently replaced, and the entire impregnated resin may also have to be replaced, which is a huge burden in terms of workability and economy. was forced. If you do not use a squeegee roller, etc., the amount of resin impregnated will be large and you will only be able to obtain a product with a low glass content.
Another problem is that defective products with a large amount of air bubbles frequently occur. In addition, the above method requires preliminary equipment to prepare the resin-impregnated roving into prepreg, which increases the burden on the equipment.Also, it is necessary to ensure a certain pot life in the prepreg state, so the curing time is short. The resin is difficult to use and the curing time is also quite long. Moreover, the resin impregnation process for producing prepregs imposes economic and physical burdens, such as replacing impregnating equipment and equipment and completely replacing the impregnated resin, as in the above-mentioned method. The inventors of the present invention focused on the above-mentioned circumstances and developed a system that satisfies all aspects of workability, productivity, and performance.
We have been conducting intensive research to provide a manufacturing method for FRP pipes. As a result, it was found that the above object could be successfully achieved by adopting the method shown below, and the present invention was finally completed. In other words, the configuration of the FRP pipe manufacturing method according to the present invention is as follows:
In forming the FRP layer, the glass fibers to which the curable resin composition is not attached are wound onto a core mold, and the curable resin composition coated on the core mold before winding and/or after the winding is applied. The gist is that the curable resin composition to be applied is allowed to adhere and permeate the glass fiber layer on the core mold. In the present invention, after attaching the required amount of curable resin to the core mold by appropriate means such as spraying or coating, the glass fibers to which no curable resin is attached are wound, or the glass fibers are wound. After being wound around a core mold, a curable resin is applied to the outer periphery of the core mold, and the curable resin adheres and penetrates into the glass fiber layer on the core mold.If the amount of resin applied is adjusted appropriately, there will be no excess resin. do not have. Moreover, since a curing agent or curing accelerator can be mixed with the base resin according to the amount used just before application, the pot life is sufficient from preparation to application penetration in an extremely short time, and fast-curing products can be used. can be used without any problems. Therefore, it is possible to cure not only thin-walled pipes but also thick-walled pipes in a short time.
Productivity can be dramatically increased. Moreover, in the present invention, as mentioned above, the required amount of curable resin is prepared each time and all is consumed, so there is no problem such as total replacement due to the curing of the circulating resin as in the conventional case. There is no risk of this occurring, and the frequency of failure and replacement of incidental equipment is drastically reduced. Furthermore, the tension when winding glass fiber [count (Tex)]
x (0.09 to 0.5) g/one roving], which is extremely important for ensuring that the curable resin penetrates into the glass fiber layer in a short time. In other words, the curable resin permeates through the glass fiber layer while purging the air due to capillary action, but if the tension during winding is set within the above range, the resin permeates efficiently, resulting in a high quality product with no bubbles. FRP pipes are obtained. By the way, Table 1 shows the winding tension applied to the glass fiber and the permeation rate of the curable resin when manufacturing FRP pipes with different glass fiber contents [Glass fiber/Glass fiber + Resin x 100 (wt%)]. This shows the results of investigating the relationship. As is clear from these results, in order to ensure resin penetration and air purging, it is necessary to keep the tension within the above-mentioned preferred range. However, if the tension is too high, the glass fibers may break during winding, the glass fiber wound layer may become too dense, impeding penetration, or it may become difficult to adjust the glass fiber content. Therefore, the tension should be kept below Tex x 0.5g/one roving. In addition, when adhering and penetrating the resin into the glass fiber, if you press it from the outer periphery with a roller, etc.
This is preferable because resin penetration and air purging can be carried out in a shorter time.

[Table] ×: No penetration △: Penetration but bubbles remain ○: Good penetration and no bubbles.
Since the curable resin used in the present invention does not itself require a long pot life, an appropriate amount of a curing agent (such as MEKPO) or a curing accelerator (such as MEKPO) is added to unsaturated polyester resin, epoxy resin, phenol resin, vinyl ester resin, etc. All known resins for FRP materials containing cobalt naphthenate (cobalt naphthenate, etc.) or their improved resins can be used, and there is no need to worry about room temperature curability or thermosetting. In view of the characteristics, the characteristics can be most effectively exhibited by using a resin with a short pot life that cures quickly at room temperature or relatively low temperature. The present invention is roughly constructed as described above, and its effects can be summarized as follows. Since a curable resin with a short pot life can be used without any problems and the curing time can be significantly shortened, the productivity of not only thin-walled pipes but also thick-walled FRP pipes can be significantly improved. Since the method involves preparing the required amount of resin each time and consuming it all in sequence, there is no wastage of curable resin. Since the resin cured product does not impede the feeding performance of glass fibers or make ancillary equipment unusable, there is less burden on workers, and it is also excellent in terms of production management and equipment management. Since the hardening resin purges air during the permeation process, high-performance FRP pipes with few air bubbles can be obtained.

Claims (1)

[Scope of Claims] 1. A method for manufacturing an FRP pipe, in which, in forming an FRP layer, glass fibers to which no curable resin composition is attached are wound around a core mold, and before winding, A method for manufacturing an FRP pipe, characterized by allowing a curable resin composition that has been applied on the core mold and/or a curable resin composition that is applied after winding to adhere to and permeate the glass fiber layer on the core mold. . 2 The glass fiber to which the curable resin composition is not attached is placed on the core mold [count (Tex) x (0.09 to 0.5)].
The method for manufacturing an FRP pipe according to claim 1, wherein the FRP pipe is wound with a tension of [g/one roving].