JPS62134250A - Production of carbon fiber reinforced synthetic resin pipe - Google Patents

Abstract

PURPOSE:To produce a carbon fiber reinforced synthetic resin pipe having high shape quality of which the outer surface is made smooth free from unevenness, by performing the removal of the residual air and excessive resin in a prepreg layer and the curing of a resin. CONSTITUTION:After a prepreg tape (a) is wound around a mandrel 1 composed of a metal having high coefficient of linear expansion, a metal foil 4 having coefficient of linear expansion lower than that of the mandrel is allowed to cover the entire outer periphery of the prepreg layer A so that the edge parts thereof are overlapped with each other. At the same time, an air-permeable tightening tape 5 is wound around the outer periphery of said metal foil 4 to tighten the prepreg layer. In this state, the residual air or residual air and excessive resin in the prepreg layer is removed by a means such as a vacuum sucking means through the lap parts of the metal foil and the tightening tape. Then, the whole is heated to the curing temp. of the resin to cure the resin while the prepreg layer is pressurized from the inside by the heat expansion of the mandrel. Thereafter, the tightening tape and the metal foil are peeled off. Thereafter, the molded pipe A' is demolded from the mandrel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing carbon fiber reinforced synthetic resin pipes.

[Prior art]

Carbon fiber reinforced synthetic resin pipes (hereinafter referred to as CFRP pipes) have extremely high strength, Young's modulus, bending elasticity, etc.
In addition, because of its light weight, it has become widely used as an alternative to conventional metal tubes for helicopter drive shafts and antenna masts for communications satellites such as L1.

This CFRP pipe has conventionally been manufactured by the method described in Japanese Patent Publication No. 53-16427. The manufacturing method of this CFRP pipe involves wrapping a brippreg tape made of a large number of carbon fibers aligned in the same way and bonded with uncured thermosetting synthetic resin around the outer periphery of a mandrel made of a metal with a large coefficient of linear expansion. A coarse fiber tape that allows the flowing resin to pass through the prepreg layer, and a resin absorption material that absorbs the excess resin of the prepreg layer are sequentially wrapped around the outside of this prepreg layer, and the excess resin of the prepreg layer is removed by vacuum suction. After absorbing the remaining air in the layer (air that sometimes enters between the tapes when wrapping the prepreg tape) through the fiber tape and absorbing this excess resin with the resin absorbing material, the resin of the prepreg layer is removed. The prepreg layer is heated to a temperature that cures it, and the resin is cured while applying pressure to the prepreg layer from the inside due to the thermal expansion of the mandrel.Then, the temperature is lowered, and the resin absorption material impregnated with excess resin and the fiber tape are peeled off. This is a method in which a molded tube is cut out from a mandrel that has shrunk due to heat drop. According to this manufacturing method, a CFRP tube can be manufactured easily and efficiently.

Recently, in addition to the conventional bleed type prepreg tape, which has a surplus of resin, non-bleed type prepreg tapes, in which the amount of resin is controlled to the minimum necessary, have also been used. CER has been achieved using this non-bleed type prepreg tape.
When manufacturing P-tubes, there is no need to absorb excess resin from the prepreg layer, so in this case, a breathable fiber tape is wrapped around the outside of the prepreg layer wrapped around a mandrel, and vacuum suction is used to remove excess resin from the prepreg layer. After absorbing the residual air, the resin of the prepreg layer may be cured.

[Problem that the invention seeks to solve]

However, in the above conventional manufacturing method, the manufactured C
On the outer surface of the FRP pipe, traces of the fibers from the fiber tape wrapped around the outside of the prepreg layer remain in a mesh pattern, and if the fiber tape wrapped around the outside of the prepreg layer has wrinkles, this " Since wrinkles also remain on the outer surface of the tube, there is a problem in that a CFRP tube with a smooth outer surface without irregularities cannot be obtained. This is the same when a perforated resin film with a large number of holes is used instead of the fiber tape, and in that case as well, there are no traces of the holes in the perforated resin film on the outer surface of the manufactured CFRP pipe. Traces of the "wrinkles" of this resin film will remain. This unevenness on the outer surface of the tube is caused by the CF
Although the RP pipe itself does not affect the orchestral body, etc., it has a poor appearance, and depending on the use of the CFRP pipe, the unevenness of the outer surface of the pipe may be a problem.

Note that if the outer surface of the manufactured CFRP tube is polished, the outer surface of the tube can be finished to a smooth surface with no irregularities, but this will cut the carbon fibers on the outer surface of the tube, so the CFRP tube cannot be polished. This will reduce the strength etc.

[Means to solve problems]

In this invention, after wrapping a prepreg tape around a mandrel made of a metal with a large coefficient of linear expansion, a metal foil having a coefficient of linear expansion sufficiently smaller than that of the mandrel is wrapped around the edges of the prepreg layer on the outside of the prepreg layer. The prepreg layer is coated to cover the entire circumference, and a breathable bonding tape is wrapped around the outer circumference of the metal foil to tighten the metal foil to the prepreg layer. After removing residual air and excess resin through the metal oil wrap and binding tape, the resin is heated to the curing temperature of the resin and the prepreg layer is pressurized from the inside by thermal expansion of the mandrel, and the resin is cured. The problems of the prior art described above are solved by peeling off the binding tape and metal foil and cutting out the molded tube from the mandrel.

[Effect]

That is, this invention covers the outside of a prepreg layer wound around a mandrel with a metal foil having a coefficient of linear expansion sufficiently smaller than that of the mandrel so as to cover the entire circumference of the prepreg layer by wrapping the edges thereof together. This metal foil is fastened to the prepreg layer with a breathable binding tape, and residual air or residual air and excess resin in the prepreg layer are removed and the resin is cured. Since residual air in the prepreg layer or excess resin combined with residual air is removed through the wrapped portion of the metal foil, there is no need to provide holes in the metal foil to allow air or fluidized resin to pass through. Therefore, there is no problem of fiber traces of the fiber tape or traces of holes of the perforated resin film remaining on the outer surface of the CFRP pipe manufactured by conventional manufacturing methods. Moreover, in this invention, since the metal foil is made of a material having a coefficient of linear expansion sufficiently smaller than that of the mandrel, even if the mandrel thermally expands during resin curing, the metal foil hardly elongates due to heat.
Even if there are wrinkles in the metal foil covering the prepreg layer,
When the prepreg layer is pressurized from the inside due to thermal expansion of the mandrel, the metal foil tightened from the outside by the binding tape is tensed by the pressing force from the inside, and the "
The "wrinkles" will be smoothed out, and therefore, no trace of a "wrinkle" of the fiber tape or perforated resin film will remain on the outer surface of the manufactured CFRP tube as in conventional manufacturing methods.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a method for manufacturing a CFRP pipe in the order of steps.

Note that this example uses a bleed type prepreg tape that requires absorbing excess resin.

In FIG. 1, numeral 1 in the figure is a molding mandrel. The mandrel 1 is made of a metal tube, such as an aluminum tube, with a large coefficient of linear expansion, and its outer surface is finished smooth and hardened by Toughflam treatment or the like.

To explain the manufacturing method of this CFRP pipe, first, 1.
After applying #l type agent such as silicone grease to the outer surface of the mandrel 1, as shown in Fig. 1(a), a large number of carbon fibers are arranged around the outer circumference of the mandrel 1 in the same direction. A prepreg tape a bonded with a hardened thermosetting synthetic resin is uniformly wrapped to a required thickness depending on the wall thickness of the CFRP pipe to be manufactured.

Figure 2 shows how to wrap this prepreg tape a.If the direction of the carbon fiber is oblique to the axis of the CFRP tube to be manufactured, the method shown in Figure 2(a) is as shown in Figure 2(a). Either wrap a strip-shaped narrow 11 prepreg tape a with carbon fibers running through it in the length direction around the mandrel 1 in a spiral shape, or as shown in Figure 2(b), wrap the tape approximately the same length as the CFRP tube to be manufactured. A wide prepreg tape (cut from a prepreg tape material diagonally with respect to the direction of the carbon fibers) a, which is wide and has carbon fibers running diagonally through it, may be wound around the mandrel 1 in the form of a roll. In addition, when the direction of the carbon fiber is parallel to the tube axis direction, as shown in FIG.
The limb can be placed along the axial direction, or as shown in Figure 2 (d).
As shown in Figure 1, there is a wide
11 prepreg tape a can be wound around the mandrel 1 in a roll shape. Furthermore, if the direction of the carbon fibers is perpendicular to the tube axis direction, the carbon fibers can be passed vertically as shown in Fig. 2(e). What is necessary is to wind the wide prepreg tape a around the mandrel 1 in a roll shape.

Note that some CFRP pipes only require carbon fibers to pass in one direction, while others require two or more carbon fibers to pass in the -L direction. The second winding is
Depending on the type of CFRP pipe to be manufactured, one of the above winding methods may be selected or a combination of two or more may be performed.

To wrap the prepreg tape 2 around the mandrel,
This is done by heating the mandrel 1 to a temperature at which the resin of the prepreg tape 2 flows, and when the prepreg tape 2 is wrapped around the outer circumference of the mandrel 1 a predetermined number of times to a uniform thickness, the wrapped Prepreg tape 2
The resin becomes fluidized by the heat of the mandrel 1, and the laminated prepreg tapes A become one prepreg layer A.

After this, as shown in FIG. 1(b), first wrap a resin blotter 2 such as glass cloth around the outside of the prepreg layer A, and make the outside airtight with a backpack film 3 such as a nylon film. Back up and perform temporary bagging. This temporary bagging is carried out in a closed tank, and the air inside the pack is vacuum-sucked and gradually heated to a temperature at which the resin of the prepreg layer A flows, and the tank is further pressurized to about 6 atmospheres. For example, most of the residual air and excess resin in prepreg layer A are removed by vacuum suction force and pressure from the surroundings (excess resin is removed by resin absorbing material 2).
(absorbed by).

After performing this temporary bagging, the pack pack film 3 and the resin absorbing material 2 are removed, and if there are any irregularities on the outer surface of the prepreg layer A, they are leveled with a roller or the like. As shown in FIG.
A sheet of metal foil 4.4 is wrapped around the entire circumference of the prepreg layer A by wrapping the edges thereof together. The metal foil 4.4 has a thickness of about 0.5 to 0.8 mm and can be bent freely. /2 stainless steel foil is used. This metal foil 4
．． 4 is cut into a piece 111 having approximately the same length as the length in the direction of the prepreg layer A and slightly wider than the length of one circumference of the prepreg layer, and this metal foil 4.4 is shown in FIG. As shown, first one sheet of metal foil 4 is placed along the axial direction around half of the prepreg layer A, and then another sheet of metal foil 4 is placed around the other half of the prepreg layer A at both side edges thereof. The prepreg layer A is wrapped so as to cover the entire circumference of the prepreg layer A as shown in FIG. In addition,
The surface of the metal foil 4.4 in contact with the prepreg layer A is subjected to a peeling treatment by applying a peeling agent such as silicone grease.

After this, as shown in FIG. 1(d), first, Teflon taffeta (
A breathable bondage tape 5 that can pass through a fluid resin such as a commercially available product is wrapped tightly around the metal foil 4 so that it does not loosen.
．． 4 to the outer periphery of the prepreg layer A. FIG. 5 shows a method of winding the binding tape 5. The binding tape 5 is wound in a spiral shape so that the side edges are not flat.

Next, as shown in FIG. 1(e), a resin absorption material 6 such as glass cloth is wrapped around the outside of the bondage tape 5 to a required thickness, and a backpack film 7 such as a nylon film is further wrapped around the outside of the binding tape 5. The material is packed in an airtight state, and main bagging is performed to completely remove the excess resin from the prepreg layer A. This bagging is also carried out in a closed tank, and the air inside the pack is vacuum-sucked and gradually heated to a temperature at which the resin of prepreg layer A flows, and the tank is further pressurized to about 6 atmospheres. , prepreg layer A
All of the residual air and excess resin inside are removed by vacuum suction and pressure from the surroundings through the wrap portion of the metal foil 4.4 and the binding tape 5 (the excess resin is removed by the resin absorbing material 2). (absorbed). Note that the wrap [11] of the metal foils 4, 4 is approximately 15 to 20 mm, and if the wrap 111 is of this extent, the residual air and excess resin in the prepreg layer A will flow through the metal foils 4, 4 without resistance. is removed through the lap part of the

After performing this main bagging, the resin is heated to the curing temperature of the resin of the prepreg layer A while maintaining this state, and the resin is cured while pressurizing the prepreg layer A from the inside by thermal expansion of the mandrel 1.

In this case, since the coefficient of linear expansion of the metal foil 4.4 is sufficiently smaller than that of the mandrel 1, even if the mandrel 1 thermally expands, the metal foil 4.4 hardly experiences any elongation due to heat. .4 is tightened from the outside with the binding tape, so the metal foil 4゜4 does not escape to the outside, so it is tightened from the outside with the binding tape by the pressure from the inside due to the thermal expansion of the mandrel 1. metal foil 4
, 4 is nervous. Therefore, even if the metal foil 4.4 coated on the prepreg layer A has wrinkles, the metal foil 4.4 will be stretched during curing of the resin and the wrinkles will be smoothed out. The resin A is cured using the metal foil 4.4 with the wrinkles smoothed out as an outer mold.

After this, wait for the resin of the prepreg layer A to harden, remove the hack pack film 7 and the resin blotting pad 6,
Furthermore, the binding tape 5 is removed and the metal 7+4.4 is peeled off, and the cured prepreg layer A, that is, the molded tube, is die-cut, and the end of the molded tube A' shown in FIG. 1(f) is finished cut. Complete the CFRP pipe.

In other words, this CFRP pipe manufacturing method uses mandrel 1
A plurality of metal foils 4, 4 having a coefficient of linear expansion sufficiently smaller than that of the mandrel 1 are placed on the outside of the prepreg layer A wound around the mandrel 1 so as to cover the entire circumference of the prepreg layer by wrapping their edges together, This metal foil 4.4 is fastened to the prepreg layer A with a binding tape 5, and a resin absorption material 6 is wrapped around the outside of the metal foil 4.4 to remove residual air and excess resin in the prepreg layer A and cure the resin. It is characterized by
In this manufacturing method, the residual air and surplus resin in the prepreg layer A are removed through the lapped portion of the metal foil 4.4, so the metal foil 4.4 has a There is no need to provide holes or the like, so there is no problem of U & fiber marks of the fiber tape or hole marks of the perforated resin film remaining on the outer surface of the CFRP pipe manufactured by conventional manufacturing methods. Moreover, in this manufacturing method, since the metal foil 4.4 has a coefficient of linear expansion sufficiently smaller than that of the mandrel 1, even if the mandrel 1 thermally expands during resin curing, the metal foil 4.4 will not be exposed to heat. Therefore, even if there are wrinkles in the metal foils 4, 4 covered with the prepreg layer A, when the prepreg layer A is pressurized from the inside due to thermal expansion of the mandrel 1, the bonding tape The metal foils 4, 4, which are tightened from the outside at step 5, are tensed by the pressure from the inside and their "wrinkles" are smoothed out. There are no wrinkles left behind from fiber tape or perforated resin film.

Therefore, according to this CFRP pipe manufacturing method, the CFRP pipe has a high shape quality with an uneven outer surface and a smooth inner surface.
Tubes can be manufactured.

In the above example, before covering the outer periphery of the prepreg layer A wound around the mandrel 1 with metal foils 4, 4, temporary bagging is performed to remove most of the residual air and excess resin in the prepreg layer A. However, when the thickness of the prepreg layer A wound around the mandrel 1 is thin, such as when manufacturing a thin-walled tube, the temporary bagging may be omitted. Further, in the above embodiment, the prepreg tape a is manufactured in one step.
Although the prepreg tape a is wrapped around the mandrel 1 until the thickness corresponds to the wall thickness of the FRP pipe, if a thick walled pipe is manufactured, the prepreg tape a may be wrapped in multiple steps.
In that case, temporary bagging may be performed each time the prepreg tape a is wrapped to an appropriate thickness. In addition, when winding the prepreg tape and temporary bagging are repeated in this way, if the amount of prepreg tape wrapped at one time is small, the temporary bagging may be performed only by vacuum suction and heating.

Furthermore, in the embodiment described above, two metal foils 4.4 are coated on each half circumference of the prepreg layer A wound around the mandrel 1, but when manufacturing a large diameter CFRP tube, the prepreg layer The entire circumference of A may be divided into two or more regions and two or more metal foils may be coated to cover the entire circumference of the prepreg layer.Also, when manufacturing a long CFRP pipe, the prepreg layer A
The prepreg layer may also be divided into several regions in the length direction, and each region may be covered with metal foil by wrapping the edges so as to cover the entire length of the prepreg layer. Further, the metal foil may be wrapped in a tape shape and wrapped around the edges in a spiral manner.

In addition, in the above embodiment, a bleed type prepreg tape that requires absorbing excess resin is used, but in this invention, a CFRP pipe is manufactured using a non-bleed type prepreg tape that does not require absorbing excess resin. In that case, only the residual air in the prepreg layer A needs to be removed, so a breathable binding tape 5 is wrapped around the outer periphery of the metal foil 4 and the metal foil 4 is attached to the prepreg layer A. It is sufficient to perform bagging and curing of the resin with only the bolts tightened.

〔Effect of the invention〕

In this invention, a metal foil having a coefficient of linear expansion sufficiently smaller than that of the mandrel is coated on the outside of a prepreg layer wound around a mandrel so as to cover the entire circumference of the prepreg layer by wrapping the edges of the metal foil with each other. According to this invention, the foil is fastened to the prepreg layer with binding tape, and residual air or residual air and excess resin in the prepreg layer are removed and the resin is cured. CFRP with high shape quality and smooth surface with no unevenness
Tubes can be manufactured.

[Brief explanation of drawings]

The drawings show one embodiment of this invention, and FIG.
Figure 2 is a plan view showing the method of wrapping prepreg tape around a mandrel, Figure 3 is a plan view showing the method of covering the prepreg layer with metal foil, and Figure 4 is a diagram of the manufacturing process for FRP pipes. Enlarged sectional view of the layer covered with metal foil, No. 5
The figure is a plan view showing a method of wrapping the binding tape around the outer periphery of the metal foil. 1...Mandrel, a...Prepreg tape, A.
...Prepreg layer, 2...Resin absorption material for temporary bagging, 3...Backpack film for temporary bagging, 4.
... Metal foil, 5... Bondage tape, 6... Resin blotter, 7... Backpack film, A'... Molded tube. Applicant's agent Patent attorney Takehiko Suzue No. 11''!1 Figure 2

Claims (1)

[Claims] On the outer periphery of the mandrel made of metal with a large coefficient of linear expansion,
After wrapping a prepreg tape made of a large number of carbon fibers aligned in the same direction and bonded with an uncured thermosetting synthetic resin, a metal foil with a linear expansion coefficient sufficiently smaller than that of the mandrel is placed on the outside of this prepreg layer. The edges are lapped together to cover the entire circumference of the prepreg layer, and a breathable binding tape is wrapped around the outer circumference of the prepreg layer to tighten the metal foil to the prepreg layer. After removing residual air or residual air and excess resin in the prepreg layer through the wrap portion of the metal foil and the binding tape, the prepreg layer is heated to the curing temperature of the resin and thermally expanded by the mandrel. A method for producing a carbon fiber reinforced synthetic resin tube, which comprises curing the resin while applying pressure from the inside, then peeling off the binding tape and metal foil, and cutting out the molded tube from the mandrel.