JPH0585344B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a fiber-reinforced thermosetting resin (hereinafter referred to as FRP)
This invention relates to a method for manufacturing a cylindrical molded article. Low-speed rotational molding of FRP cylindrical moldings was published in Japanese Patent Application Laid-Open No. 1985.
-111577. That is, the cylindrical mold does not move in the direction of the rotation axis, and the mold is moved from 1 to
Rotate at 4 rpm (circumferential speed 5 to 10 m/min), install a pressure roller parallel to the rotation axis direction of the mold, and synchronize the rotation of the mold and the rotation of the pressure roller from the drive unit using a chain or wheel. A molding method has been proposed in which the reinforcing material is impregnated with resin and defoamed while adjusting the pressure roller by moving it up and down using an air cylinder, that is, applying pressure and releasing the pressure. However, in this forming method, since the molding material supply device and the pressing roller move along the guide rails on the side of the cantilever beam, the bending moment acting on the beam changes, which causes the beam to deflect. arise. This deflection makes it impossible to keep the pressure roller connected to the guide rail installed on the cantilever beam body horizontal, resulting in uneven thickness and entanglement of the molding material with the pressure roller during molding. In addition, in this method, when the material supply device is moved from the leading end to the rear end with the material supply stopped, the fiber reinforced material is a long fiber before it is cut with a cutter on the device, so it becomes sagging and does not work properly. This may cause problems such as getting tangled with parts or coming into contact with the mold surface. Furthermore, since the conduit for transporting the liquid thermosetting resin needs to have a telescoping structure, the inside of the conduit cannot be completely cleaned. Moreover, since the structure is complicated, the number of conduits is limited. Furthermore, in this method, the press roller is driven by a chain and rotates in synchronization with the rotation of the cylindrical mold, so the mold must be made into a perfect circle, making it difficult to manufacture molded products with shapes other than perfect circles, such as ellipses, missing circles, and polygons. is not suitable.
Moreover, since the press roller is rotated in synchronization with the mold, there is a drawback that molding becomes difficult if the molding material becomes entangled with the roller. The present inventors conducted intensive research to improve these drawbacks, and as a result, they arrived at the present invention. That is, the present invention provides (a) a cylindrical mold that rotates with a centrifugal force smaller than twice the force of gravity and is capable of reciprocating motion in the axial direction, and moves the inside of the mold continuously or intermittently in the axial direction; (b) supplying fiber reinforcement of short fibers and liquid thermosetting resin to the wall surface by (c) a fiber reinforcement supply device fixed to a cantilever beam located in the mold interior space; ) Next, with at least one press roller fixed to the cantilevered beam body and freely movable and rotating, (e) impregnating and defoaming the reinforcing material and resin by pressing them with the weight of the press roller. The present invention provides a method for manufacturing a molded article. In the present invention, a fiber reinforcement supply device is provided to the cantilever beam body,
By fixing the liquid thermosetting resin supply device and the pressure roller device, the structure of the cantilever beam can be simplified, and the length of the beam can be increased. This allows long FRP
It becomes possible to manufacture a cylindrical molded product. In addition, each conduit for transferring the fiber reinforcement material and liquid thermosetting resin to each supply device can be fixed, eliminating the need for an expandable mechanism, and in addition, it is possible to achieve a significant weight reduction. Note that the liquid thermosetting resin supply device can have a mechanism for mixing just before or after the discharge port, so that the catalyst, accelerator, etc. can be completely mixed. The cylindrical mold used in the present invention is preferably one that can be opened and closed in at least two parts as shown in FIG.
Rotation of the mold is carried out, for example, by means of a plurality of transmission rollers driven by a motor. The rotational speed of the cylindrical mold is such that the centrifugal force is less than twice the force of gravity. For example, if it is a cylindrical type with a diameter of 2m, the diameter is 30r.
The rotation speed is less than pm. Further, the cylindrical mold can be reciprocated in the axial direction of the mold at a constant or variable speed in the range of 0 to 20 m/min, for example, along a guide rail by a cylindrical mold moving device, and the mold can be moved freely, for example. A mechanism is used that allows the mold to be reversed back and forth using guide rails, and the mold can be rotated both left and right. The axial movement of the mold may be achieved by driving wheels, or by driving a chain, wire, gear, or the like. For example, as shown in Figure 2, the fiber reinforcing material supply device guides and transports the fiber reinforcing material, such as a string-like material, using a rubber roller, and is composed of a rubber roller and a shearing blade roller having radial shearing blades, and operates the shearing blade roller. , has a mechanism that can cut and supply the fiber reinforcement material by releasing it, or supply the fiber reinforcement material in the form of a string by replacing the shearing blade roller with a roller without shearing blades in Figure 2. things are used. The supply amount can be freely selected, and when it is supplied in the form of a string, it can be supplied in parallel or in a spiral in the circumferential direction in synchronization with the circumferential speed, or it can be supplied in a random loop at a higher speed. Moreover, these may be supplied in combination. The liquid thermosetting resin supply device mixes the liquid thermosetting resin, curing catalyst, etc. before supplying it to the inner wall surface of the cylindrical mold, as shown in FIG. 4, for example.
Preferably, the liquid thermosetting resin can be mixed immediately before or after the discharge port. A method of supplying this device when unsaturated polyester resin is used as the liquid thermosetting resin will be described. A mixture of unsaturated polyester resin and accelerator, such as 6% cobalt naphthenate, is pumped into a line mixer. Further, in a separate line, a catalyst such as 55% methyl ethyl ketone peroxide (MEKPO) is transferred to the line mixer by a pump. Both are mixed by a line mixer and then discharged and supplied from a discharge port. The discharge port preferably has pores on the lower surface of a pipe with both ends closed and discharges in the form of a shower, but it may also discharge in the form of a slit or mist. Unsaturated polyester resin and 55
A metering pump is usually used to transfer %MEKPO, and the transfer ratio is 100:0.2 or
It has a ratio of 100:5 and can be a gear type, air pump type, or pressure feeding type. Alternatively, the unsaturated polyester resin, the promoter, and the catalyst may be transferred through separate lines and mixed and supplied by two line mixers. For example, as shown in Figure 4, the pressure roller rotates freely without being forced to synchronize with the rotating mold, impregnating the reinforcing material with resin by the pressure of its own weight, and defoaming the bubbles in the molding material. It is preferable to have at least one crank so that it can move freely. The weight of such a pressure roller is 50 to 400 g per 1 cm of roller length, and the length can be freely selected depending on the length of the molded product, and is usually 10 to 400 g.
A range of 100 cm is suitable. Also, its diameter should be 5 to 40 mm as long as it does not interfere with rotation.
A range of is preferred. The pressure rollers preferably have a mechanism that can be moved up and down using an air cylinder, and three or more pressure rollers are usually used with an interval of 1 to 50 cm, preferably 5 to 20 cm. As the fiber reinforcement used in the present invention, generally known fiber reinforcement materials such as glass fiber, carbon fiber, and aramid fiber (Kepler fiber, manufactured by DuPont) can be used, and glass fiber is preferable. In addition, the shape of this fiber is pine-like, tape-like,
A roving (thread-like) shape or a tip stride shape obtained by cutting a roving-like material to an appropriate length, preferably 12 to 75 mm, is suitable, and a combination of these is also possible. The content of the fiber reinforcing material in the molded product is suitably in the range of 10 to 80% by weight, preferably 20 to 60% by weight. The liquid thermosetting resin used in the present invention can be a generally known liquid thermosetting resin such as unsaturated polyester resin, vinyl ester resin, epoxy resin, or phenol resin, and preferably unsaturated polyester resin or vinyl ester resin. Resin is used. The viscosity of liquid thermosetting resin is usually 0.5
~20 poise (Bruckfield viscosity), preferably 2 to 20 poise. When an unsaturated polyester resin or vinyl ester resin is used as the liquid thermosetting resin, a vinyl monomer such as styrene or methyl methacrylate is mixed with the unsaturated polyester or vinyl ester as a constituent component. Furthermore, a curing aid such as cobalt naphthenate, cobalt octenoate, lead naphthenate, lead octenoate, etc. may be added to these resins in advance. Of course, it may be added when supplying the resin to the rotary mold. Next, the manufacturing method of the present invention will be explained using an apparatus. FIG. 1 shows an example of a molding apparatus in which a molding material supply section, a press roll, etc. are installed so as not to move in the direction of the rotation axis of the mold, and the mold can move in the direction of the rotation axis. In this device, a cylindrical molding die A is rotated by a roller 5 that transmits the drive of a motor 2. Resin and fiber reinforcement are supplied to the rotating inner surface of the mold from a molding material supply device provided on the cantilever beam B and a press roll mounting portion C, and are pressed by a press roller D immediately after being supplied. At this time, the molding die A moves forward or backward to proceed with molding as the molding material is supplied from the molding material supply device and the mounting portion C of the press roll. Further, the speed of the rotation and back-and-forth movement of the mold body A is appropriately selected by the multi-speed transmissions 3 and 6. According to the present invention, it is possible to make the material supply section and the cantilever beam body compact, and it is possible to obtain a long FRP cylindrical product having a large diameter to a small diameter, and it is also possible to manufacture irregularly shaped pipes. Furthermore, a fiber reinforced material such as glass roving can be supplied without being cut, and a high-strength FRP cylindrical molded product can be obtained. Furthermore, since the liquid thermosetting resin and the curing catalyst are completely mixed, an FRP cylindrical molded product with no uneven color can be obtained. The present invention will be explained by examples. Example 1 The mold body A has an inner diameter of 1.8 m and a length of 6 m.
The process was carried out using a manufacturing apparatus as shown in Figure 1. Eight glass fibers (Glass Roving SP-3, manufactured by Asahi Fiber) were fed into a tip strand shape with a length of 50 mm using a fiber reinforcement supply device installed almost at the tip of the 3.5 m long cantilever beam B. Cut into 4kg/
The unsaturated polyester resin (Polylite FH-
105 (manufactured by Dainippon Ink & Chemicals) 100 parts by weight + 6
% cobalt naphthenate (0.4 parts by weight) and catalyst (55
%MEKPO) was mixed at a ratio of 1.0 parts by weight of catalyst to 100 parts by weight of resin, and the mixture was fed onto the glass fibers in a shower at a rate of 8 kg/min using a liquid thermosetting resin feeding device. After that, the top is pressed with three pressure rollers to impregnate and defoam, and it is continuously molded. When about 3 m is molded, the supply of glass fiber and resin is stopped, and mold A for single-layer molding is formed. was separated from cantilever beam body B. Turn the mold body A back and forth, move the mold body so that the beam body B enters the mold body A, and mold it in the same way as above, following the molded one previously, to a length of 6 m. A cylindrical molded product with a thickness of 9 mm was manufactured. Table 1 shows the physical properties of this molded product. In addition, each pressure roller has a diameter of 15 cm, a length of 60 cm,
It weighs 10Kg and the distance between each roller is 10cm. Example 2 Using the internal rotational molding manufacturing device shown in Figure 1, a cylindrical mold A with a diameter of 2.8 m and a length of 3 m was rotated at a rotation speed of 2.8 rpm (peripheral speed of 24.6 m/min) and the rotation speed was 0.3 m in the axial direction.
The glass fibers were moved back and forth at a constant speed of m/min and molded under the same supply conditions as in Example 1, and when the glass fibers were molded to a thickness of 3 mm and a length of 3 m, the glass fibers were not cut into chopped strands but were made into long fibers, i.e. It was continuously supplied randomly in the form of rovings and formed into a thickness of 3 mm. Next, chopped stride glass fibers were again supplied on top of the glass fibers, and the thickness was 3 mm in the same manner as in Example 1.
A cylindrical molded product with a length of 3 m and a thickness of 9 mm was obtained. Table 1 shows the physical properties of this molded product.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a rotary molding apparatus used in the present invention, in which a molding material supply section is fixed to a cantilevered beam body and a cylindrical mold body can move back and forth. FIG. 2 is a partial view showing the fiber reinforcement supply device. FIG. 3 is a schematic diagram of a liquid thermosetting resin supply device. Moreover, FIG. 4 is a partial view showing the state of the molding material supply device and the pressing roller attached to the cantilever beam body. A... Molding mold body, B... Cantilever beam body, C...
Mounting part of molding material supply device and pressing roller,
D...Press roller, 1...Guide rail, 2...
...Motor, 3...Transmission, 4...Chain, 5
...Motor, 6...Transmission, 7...Belt, 8
...Transmission roller, 9...Hinged portion, 10...Movement wheel, 11...Fiber reinforced material, 12...Rubber roller, 13...Reinforcement rocker, 14...Motor, 15...Belt, 16 ...Fiber reinforced material supply port, 17...Air cylinder, 18...Liquid resin tank, 19...Catalyst tank, 20...Transfer pump, 21...Opening/closing valve, 22...
Line mixer, 23...Resin liquid discharge device, 24
...Air cylinder, 25...Arm, 26...
...Crank, 27...Press roller bearing, 28...
...Press roller shaft rod.

Claims (1)

[Claims] 1 (a) Rotates with a centrifugal force less than twice the force of gravity;
and a cylindrical mold capable of reciprocating in the axial direction, while moving continuously or intermittently in the axial direction, (b) applying short fiber reinforcing material and liquid thermosetting resin to the inner wall surface of the mold; (c) feeding by a fiber reinforcement supply device fixed to a cantilever beam located in the mold space; (d) at least one fiber reinforcement material fixed to the cantilever beam and freely movable and rotating; (e) A method for producing a molded article, comprising: (e) impregnating and defoaming the reinforcing material and resin by pressing them with the weight of the pressing roller.