JPH0310484B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> This invention relates to a centrifugal manufacturing method for resin concrete pipes using unsaturated polyester resin as the resin. <Prior art> Resin concrete pipes have a history of being centrifugally formed due to their excellent mechanical and physical performance.However, resin concrete pipes usually use unsaturated polyester resin as the resin and hardening agents. In this case, a room temperature curing agent was used. The room-temperature curing method that uses a room-temperature curing agent enables centrifugal forming by simply combining a commonly used centrifuge and rotating formwork, and is simple equipment that is not much different from conventional cement-based centrifugal concrete pipe manufacturing equipment. It was possible to manufacture it with This resin concrete pipe has a formwork that continues to rotate until the resin concrete that is poured into it hardens, so it takes a considerable amount of time to manufacture it, causing dissatisfaction in terms of efficiency. A resin concrete dosing machine is required to feed this into the formwork, but resin concrete naturally adheres to these machines during work, and there was no problem during the first operation, but
As the second and third work progresses, the adhering concrete begins to harden, and it has to be removed after each work. The increase in the amount of labor and time required for this process has significantly hindered production efficiency, and despite the fact that good resin concrete pipes can be obtained, production has gradually been reduced and in recent years almost no production has been done. . <Problem to be solved by the invention> In this way, if we try to shorten the centrifugal forming time and increase work efficiency in the production of resin concrete pipes, the resin concrete that adheres to work machines will harden faster. Therefore, there was a problem in that the number of times and labor for cleaning increased, which conversely reduced production efficiency. A possible solution to this problem is to use a thermosetting agent. With this curing method, the resin concrete that adheres to work machines will harden slowly unless heat is applied, making maintenance such as cleaning the machines extremely easy. Because curing requires heating, not only a rotating formwork but also a large heating chamber surrounding the centrifuge is required, as well as a combustion machine to generate hot air and a far-infrared generator. However, there is a problem in that the equipment and costs are large and expensive. <Means for Solving the Problems> The present invention provides resin concrete in which a thermosetting agent is added and kneaded into a hollow cylindrical form made of a highly rigid metal while rotating it on a centrifuge. to form a pipe body, and then a resin or resin mortar added with a room-temperature curing agent to the inner surface of the pipe body to form the inner layer of the pipe,
The inner layer is cured at room temperature or by heating, the mold is stopped rotating while the tube main body remains uncured, the mold is removed from a centrifuge, and the mold is moved. This centrifugal manufacturing method for resin concrete pipes is characterized in that the pipe is removed from the formwork after the main body of the pipe is cured. <Function> The mold used is a hollow cylindrical mold made of highly rigid metal that does not easily undergo deformation, and while rotating this on a centrifuge, the unsaturated polyester to which a thermosetting agent has been added is first added. A resin concrete made by adding aggregates such as gravel, sand, and calcium carbonate to the resin and kneading is poured into the pipe body to form the pipe body, and then the inner periphery of the pipe body is filled with resin or resin to which a room-temperature curing agent has been added. Add mortar to form the inner layer of the pipe. Next, room temperature or heated air is blown from the inside to harden the resin or resin mortar in the inner layer. Since the inner layer is thinner than the pipe main body, it hardens in a short time and becomes a kind of hardened wall.At this stage, the resin concrete in the pipe main body maintains its circular shape due to centrifugal force, but it hardens. At this point, the reaction has barely begun, so when the rotation is stopped, it will naturally deform or it will fall out of the formwork and it will be impossible to maintain its circular shape. Since the uncured pipe body is sandwiched between the inner layer, which serves as a type of hardened wall, and a highly rigid formwork, the rotation of the centrifuge and formwork is stopped, and the formwork is removed from above the centrifuge. The resin concrete of the tube main body is heated and hardened in the heating chamber, and when hardening is completed, the tube is removed from the formwork and the required amount is removed. This led to the creation of resin concrete pipes. As described above, the method for manufacturing a resin concrete pipe according to the present invention is most characterized by the two-step curing method in which the resin or resin mortar layer of the inner layer is first hardened, and then the resin concrete of the pipe body is hardened. When manufacturing resin concrete pipes with large pipe diameters and therefore large wall thicknesses, curing of the resin or resin mortar layer only on the inner layer may result in insufficient shape retention of the pipe body, resulting in damage to the pipe body. If there is a risk of deformation or falling off of the resin concrete, form one or more layers of resin or resin mortar added with a room-temperature curing agent in the middle of the resin concrete layer of the pipe body, and replace the inner layer. The intermediate charging layer is hardened together with the resin concrete in the main body of the pipe to prevent it from deforming or falling off, and the shape of the pipe as a whole is maintained when the formwork stops rotating. You can also do that. Furthermore, by selecting materials such as using ortho-based unsaturated polyester resin for the resin concrete of the pipe body and using resin or resin mortar layer using isophthalic acid-based or bisphenolic acid-based resin for the inner layer, Therefore, the chemical resistance of the pipe can be improved economically. Further, different types of resins such as epoxy resins may be used for the inner layer portion for the same purpose. Next, unsaturated polyester resin used for the resin concrete of the main body of the resin concrete pipe of the present invention is for medium temperature (hardening at about 60 to 100℃) and high temperature (hardening at 100℃ or higher) Table 1 shows examples of thermosetting agents, and Table 2 shows examples of room temperature curing agents to be added to the fluid resin and resin mortar used for the inner layer. (If an accelerator is used together, enter in the accelerator column)

【table】

[Table] <Example> Examples will be described below with reference to the drawings. Fig. 1 shows the first embodiment of the method of the present invention, in which 1 is a highly rigid metal formwork, 2 is a tube body made of resin concrete added with a thermosetting agent, and 3 is a room-temperature hardening part. The inner layer is made of resin or resin mortar containing additives. 4 indicates a reinforcing bar cage for reinforcing the pipe body, which is placed as necessary, and 5
The glass fiber layer is also inserted as needed to reinforce the inner layer 3, and is usually inserted between the tube body 2 and the inner layer 3. First, the required reinforcing bar cage 4 was charged into the rotary formwork 1, and the formwork 1 was rotated on a centrifuge, and unsaturated polyester resin to which a thermosetting agent had been added and silica sand etc. were kneaded through the openings at both ends. Add resin concrete. This resin concrete is poured into the tube body part 2 by adding slightly less than the required thickness of the pipe, then glass fiber 5 is added, and then resin mortar, which is an unsaturated polyester resin with a room temperature curing agent added, is added to form the inner layer. Mold part 3. The thermosetting agent used in the resin concrete of the pipe body part 2 is benzoylpeoxide (BPO), and the room temperature curing agent added to the inner layer part 3 is 55% methyl ethyl ketone peroxide (MEKPO) diluted with dimethyl phthalate (DMP). Cobalt soap 6% cobalt naphthenate was used as the solution and accelerator. Another method for curing the inner layer 3 is to use benzoyl peroxide (BPO) as a curing agent and add tertiary amine as an accelerator to the inner layer 3 including the glass fiber layer 5. While using the same curing agent for the tube body part 2 and the inner layer part 3, it is possible to easily change from heat curing to room temperature curing by just adding tertiary amine through the glass fiber layer 5, which is very convenient for work. You can get sex. In either method, the inner layer 3 including the glass fiber layer 5
The material is hardened prior to forming the tube body 2. The resin mortar that forms the inner layer 3 has good fluidity, so it is easily smoothed by rotational centrifugal force, and then warm air at about 100°C is applied from the inside for several minutes to harden the inner layer 3 and then centrifuged. Stop the rotation of the machine, immediately transport each formwork to the heating room, and heat the room to 100%.
After holding at ~200°C for about 1 hour, the mold was demolded. Figure 2 shows a second embodiment of the method of the present invention, in which resin concrete to which a thermosetting agent is added is charged into the formwork in two steps when forming the main body of the pipe. The intermediate layer 3b made of the same type of resin or resin mortar as the inner layer 3a is formed in the tube main body 2 by adding resin concrete or resin mortar to which the inner layer 3a is added. When manufacturing a resin concrete pipe with a large diameter and a large wall thickness, this method quickly hardens the intermediate layer 3b and the inner layer 3a and jointly works together to form a thick pipe main body part 2.
The tube main body part 2 is
This makes it possible to stop the rotation of the mold and move the mold into the heating chamber while it remains uncured. Although the above-mentioned intermediate layer 3b is one layer in the drawing, it can be formed into two or more layers to support the thick uncured tube main body portion 2. The resin concrete pipe formed for the strength test has an inner diameter of 500 mm, a wall thickness of 42 mm, and a reinforcing bar cage 4 is placed approximately in the center of the wall thickness of the pipe, so that the total cross section of the spiral reinforcement is 1.1% of the pipe cross section. In addition, the glass fibers 5 on the inner surface were arranged in an amount of 1% of the weight of the tube. The external pressure strength of this strength test tube was compared with the JIS05350 standard value for reinforced plastic composite pipes and the standard value for small diameter propulsion pipes of the National Huium Pipe Association.
Shown in the table.

[Table] However, among the pipe types, A indicates JIS5350 reinforced plastic composite pipes, and B indicates those from the National Huyum Pipe Association. Also, the * mark is the load value at a standard deflection of 26 mm, not the cracking load value. As is clear from Table 3, the resin concrete pipe of the present invention has extremely high strength compared to other plastic pipes and cement-based humid pipes, and because the resin is cured in two stages, there are no defects in strength. This can be said to be an excellent manufacturing method that further increases productivity. <Effects of the Invention> (a) By using a thermosetting agent to harden the resin concrete of the pipe body, the hardening caused by the adhesion of the resin concrete to the work machines is slowed down, making it easier to clean the work machines. This can be done easily and saves labor. (b) By molding the inner layer and accelerating the curing of the inner layer's resin or resin mortar layer by adding a room-temperature curing agent, the uncured pipe body is held together with the highly rigid outer rotating formwork. By making it movable, the rotation time of the mold for molding can be greatly reduced, and the pipe manufacturing efficiency can be dramatically improved. (c) A two-stage curing method is adopted in which the resin concrete for the pipe body is cured in a separate heating chamber, which avoids overloading the equipment. (d) In the middle of the resin concrete layer of the pipe body,
By providing one or more layers of resin or resin mortar using a room-temperature curing agent, the shape retention of the pipe main body can be strengthened in the uncured stage. (e) By effectively utilizing the characteristics of the resin concrete in the pipe body and the resin or resin mortar layer in the inner layer, many effects can be produced, such as improving the acid resistance and chemical resistance of the pipe. .

[Brief explanation of the drawing]

1 and 2 show side sectional views of different embodiments of the present invention. 1...Rotating formwork, 2...Pipe body made of resin concrete, 3, 3A...Inner layer part, 3B...Middle layer, 4...Reinforcement cage, 5...Glass fiber layer.

Claims (1)

[Scope of Claims] 1. A hollow cylindrical form made of highly rigid metal is rotated on a centrifuge, and resin concrete mixed with a thermosetting agent is poured into the form to form the tube body. Then, a resin or resin mortar containing a room temperature curing agent is poured into the inner surface of the pipe body to form the inner layer of the pipe, and the inner layer is hardened at room temperature or by heating to form the pipe body. The rotation of the mold is stopped and the mold is removed from the centrifuge while the tube main body remains uncured. After the movement, the tube main body is cured by heating means, and then the tube is removed from the mold. A centrifugal manufacturing method for resin concrete pipes, which is characterized by the fact that they can be taken out. 2. Centrifugation of a resin concrete pipe according to claim 1, wherein one layer or multiple layers of resin or resin mortar added with a room temperature curing agent are formed in the middle of the resin concrete layer constituting the pipe main body. Manufacturing method.