JPS62187019A - Draw forming method for fiber reinforced plastic cylinder - Google Patents

Abstract

PURPOSE:To prevent the temperature of moldings at the wrapping section from dropping suddenly and mold a uniform FRP cylinder by controlling a wrapping section to draw FRP cylinder moldings molded by a hot die and coming to a high temperature within a specified temperature. CONSTITUTION:A molded product 15 made of a reinforced fiber wound to a mandrel 13 and impregnated with resin is introduced into the inside of a hot die 14. After passing said hot die 14, surplus resin is removed, and external shape is completed and cured. The molded product is heated and then cooled down naturally. Then temperature at the draw wrapping section 16 is controlled by a panel heater layer 20 and a controller 21 not to lower the temperature of molded product 15, even if the mold product 15 is led into the draw wrapping section 16. By said process, without sudden lowering of temperature, residual stress generated in the molded product 15 is substantially reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a continuous molding method for fiber-reinforced plastic (hereinafter abbreviated as FRP) cylinders, particularly for lightweight and long cylinders used as members for large space structures. This invention relates to a method that can be applied to continuous pultrusion of large and thin-walled cylinders.

[Conventional technology]

FIG. 5 shows an example of molding a solid rond, and is taken from Japanese Patent Application Laid-Open No. 75263/1983 to explain the basic concept of a conventional pultrusion method and its apparatus.

In the figure, l is the reinforcing fiber drawn out from the bobbin, 2
3 is a cypress impregnated with a thermosetting resin; 3 is a resin-impregnated fiber aggregate; 4a;

4b is a hot die that removes excess resin from the aggregate 3, shapes the outer diameter, and hardens and molds it; 5 is a drawing gripping unit that has a belt-type drive mechanism that grips the molded product and pulls it out in the right direction; Al.

In the above configuration, the reinforcing fiber 1 drawn out from the 1-bin
Once aggregated, the aggregate 3 is passed through a resin tank 2f to be impregnated with a polythermosetting resin, and then the aggregate 3 is passed through hot dies 4a and 4b to remove excess resin and give an outer diameter. It is shaped and further cured to obtain a predetermined molded product. Further, this operation can be performed continuously by the pull-out grip section 5 having a belt-type drive mechanism.

The above is an example of a solid rondo, but there is a method in which a fiber aggregate impregnated with a thermosetting resin is wound around a core metal, and then pultrusion molded. 51
It is described in JP-A-58467. FIG. 6 and FIG. 7 are respective configuration diagrams. In Fig. 6, 6 is a core metal around which a fiber aggregate is wound (2) The fiber aggregate passes through a hot die 8 to remove excess resin, shape the outer diameter, and harden the molded material. 7. At this time,
The molded product 7 is gripped and driven by a pair of rollers 9a and 9b and pulled out to the right. Further, in FIG. 7, the molded product 11 that has passed through the hot die 10 is pulled out to the right by drawing grips 12a and 12b having a drive mechanism.

[Problem that the invention seeks to solve]

Usually, in a pultrusion molding method using a thermosetting resin, a hot die is heated to about 150° C. to 180° C. for curing. Furthermore, the molded product and the core metal heated and hardened by the hot die also have a temperature close to that of the hot die. on the other hand,
The temperature of the pull-out gripping portion having the drive mechanism is around room temperature;
For this reason, the molded product immediately after passing through the hot die undergoes a rapid temperature drop during the first gripping operation at the gripping section. This property will be significantly reduced. Particularly in large space structure members that are required to be lightweight through extreme design, cracks caused by this residual stress can lead to damage to the entire member.

This invention was made to solve the above problems69, and by reducing the residual stress that occurs due to the drop of V during the gripping operation, excellent physical properties and high efficiency production can be obtained. The purpose of the present invention is to provide a method for pultrusion forming a reinforced plastic cylinder.

[Means for solving problems]

The pultrusion molding method for a fiber-reinforced plastic cylinder according to the present invention is such that a pultrusion gripping portion having a drive mechanism is controlled to a predetermined temperature.

[For production]

In this invention, by controlling the temperature of the drawing gripping part having a drive mechanism to a predetermined temperature, the rapid temperature drop that the molded product receives at the drawing gripping part after passing through the hot die is avoided, and the residual stress that causes cracks is reduced. reduce

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
Figures 1 to 3 show the first embodiment, where 13 is a core bar around which the fiber aggregate is wound, and 14 is a heated writing die for removing excess resin, shaping the outer diameter, and curing. , 15 is a molded article (fiber aggregate) in a high-temperature state immediately after curing, and 16 is a drawing grip part having a drive mechanism for pulling out the core bar 13 and molded article 15 together to the right. In FIG. 2, the vertical axis represents the temperature of the molded product 15, and the horizontal axis represents the positional relationship of the molding line. Actual solution 17 shows the temperature history of the molded product 15 in this embodiment having the drawing grip part 16 having a temperature control function, and the broken line 18 shows the temperature history in the conventional method.

Furthermore, in FIG. 3, 19 is a heat insulating sheet layer for preventing heat dissipation, 20 is a silicone rubber nozzle heater layer, and 21H is a temperature controller for temperature control, and the set temperature can be freely selected by the temperature controller 21. can do.

Next, the operation of the above device will be explained. The molded article (AMM aggregate) 15 wound around the core metal 13 has reinforcing fibers impregnated with resin, and the temperature in this state is approximately room temperature. The molded product 15 and the core bar 13 are pulled to the right by a drawing grip part 16 having a drive mechanism, and introduced into the hot die 14 where they are heated to a temperature of ~180°C. The temperature has reached approximately 160°C. Next, this hot molded product 15 is allowed to cool naturally until it reaches the drawing grip part 16. If the distance between the hot die 14 and the first drawing grip part 16 is 600 mm and the drawing speed is 2 m/hr, the natural cooling time will be approximately 18 minutes, and the molding process will take place immediately before the first drawing grip part 16. The temperature of the molded product 15 is about 100°C.

In the pull-out gripping section 16, a panel heater N20 is provided at the portion that grips the molded product 15, and a heat insulating sheet layer 19 is further provided on the outer circumferential side of the panel heater N20. The temperature is regulated at ℃. Therefore, even when the molded product 15 is introduced into the drawing grip portion 16, there is no sudden temperature drop, and the residual stress generated in the molded product 15 is significantly reduced. The molded product 15 that has passed through the first drawing grip 16 is allowed to cool again naturally and reaches the second drawing grip 16. Pull-out grip part 16 .

If the distance between the molded articles 16 is 5001, the temperature of the molded article 15 immediately before the second pull-out gripping portion 16 is approximately 70°C. 2
In the @-th drawing grip part 16, the temperature is adjusted to 0°C by the temperature controller 21 as described above, and even when the molded product 15 is introduced into the drawing grip part 16, there is no sudden temperature drop. Here too, the residue 1 generated in the molding 15
Stress is significantly reduced. The molded article 15 that has passed through the second drawing grip part 16 is slowly cooled down to room temperature by natural cooling.

FIG. 4 shows a second embodiment of the present invention, in which a cylindrical molded product (resin-impregnated fiber aggregate) 22 is provided with a longitudinal notch 22a for measuring residual stress. , where Do is the outer diameter before the notch 22a is provided, and DI is the outer diameter after the notch 22a is provided, the residual stress σt in the circumferential direction of the surface can be obtained from the following equation.

However, E: modulus of longitudinal elasticity, μ: Poisson's ratio, and t: plate thickness. The pultrusion method and apparatus are the same as in the first embodiment. When the residual stress of this molded product 22 and the conventional molded product is calculated from equation 111 using the residual stress measurement method described above, the residual stress σtl'' of the conventional molded product is obtained.
kgf/guji 2), molded product obtained in this example 22
(The same applies to the molded product 15 of the first example) Residual stress σt2
= 5 (kgf/parrot2), the residual stress generated in the molded article 22 can be significantly reduced.

〔Effect of the invention〕

As described above, according to the present invention, by controlling the drawing grip part having a drive mechanism to a predetermined temperature, a rapid temperature drop can be given to the molded product that has been hardened in a hot die and brought into a high temperature state at the drawing grip part. Therefore, it is possible to realize a pultrusion molding method that can significantly reduce the residual stress generated in the molded product and can provide a fiber-reinforced plastic cylinder with excellent mechanical properties and high productivity.

[Brief explanation of drawings]

Figures 1 and 2 are a configuration diagram of the device according to the present invention and a temperature change diagram of the molded body, and Figure 3-(4) is a cross-sectional view of the upper part of the drawing grip part according to the present invention divided into upper and lower parts. FIG. 4 is a perspective view of a molded body according to another embodiment of the present invention, and FIGS. 5 to 7 are configuration diagrams of an apparatus according to a conventional method. 13...Core metal, 14...Hot die, 15.22.
... Molded product, 16... Pull-out gripping part, 20... Silicon rubber note panel heater, 21... Temperature controller.

Claims (1)

[Claims] (1) In a method in which reinforcing fibers impregnated with a thermosetting resin are wrapped around a core metal, this integrated product is gripped by a drawing grip part through a hot die, and molded while being continuously pulled out, the drawing grip part is suddenly attached to the molded product. A pultrusion molding method for a fiber-reinforced plastic cylinder characterized by controlling the temperature to a temperature that does not cause a significant temperature drop.