JPH01113227A - Manufacture of composite material bomb - Google Patents

Abstract

PURPOSE:To obtain a light and cheap composite material bomb which is easy to wind and finishes well, having favorable physical properties, by coating an outer periphery of a plastic inner cylinder with a sheet of reinforced fibers, and then forming thereon a fiber-reinforced plastic layer through the filament winding method. CONSTITUTION:An inner cylinder made of plastic in small thickness is used for an inner cylinder of a composite material bomb, which is preferably formed by the blow-molding method. According to the blow molding, after one end of a plastic pipe is sealed, the pipe is heated and expanded into an aimed shape mechanically or by adding pressure. The product formed by the blow molding is high in strength, but low in hardness. Therefore, in order to reinforce a mandrel in a circumferential direction, at least the drum portion of the mandrel which is the inner cylinder is wound by a reinforced fiber sheet. The material of the reinforced fiber sheet is glass fibers, carbon fibers, aramid fibers, etc. Over the reinforced fiber sheet, there is formed fiber-reinforced plastic layer by hardening a mold of the reinforced fibers and plastic by the filament winding method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for industrially manufacturing a composite material cylinder that is lightweight and has sufficient pressure resistance. More specifically, the present invention relates to an improvement in a method for manufacturing a composite material cylinder by using a pumice plastic inner cylinder manufactured by blow molding or the like as a mandrel, and molding m-fiber reinforced plastic on the surface thereof by the filament wine tongue method.

[Prior Art] Cylinder is used as a container for storing gas and/or liquefied gas, and until now, it has not been sold to the general public.

The cylinders used are made of steel. However, steel cylinders are pressure-resistant containers, so they have thick walls, and ff1ffi
There is a big drawback. For this reason, in relatively recent years, cylinders made of light metals such as aluminum and their alloys have been manufactured and are also commercially available.

Furthermore, recently, cylinders made of composite materials have been developed and become commercially available. For example, SCI Inc. (St.
Ractual Compositel ndust
This is the case for cylinders made by Ries. Such a conventionally known composite material cylinder has a fiber-reinforced plastic layer formed on the outside of a metal inner cylinder by the filament Weintongue method.

[Problems to be Solved by the Invention] Such a conventionally known composite material cylinder has a part of the wall thickness of a conventional metal cylinder made of reinforcing fibers and plastic (resin).
It is lighter than the conventional metal cylinder. However, in order to further reduce the weight, the metal parts must be eliminated or the metal parts must be made even lighter.

One possible means for this is to remove the metal inner cylinder that serves as the mandrel, but removing the mandrel from a cylinder manufactured by winding it using the filament wine tongue method requires destruction or deformation of the mandrel. Although this method is theoretically possible to implement, current technology has drawbacks in terms of cost and technology. There is also the problem of gas permeability of fiber-reinforced plastics (FRP) (for example, in JP-A-62-10!1701, FRP
There is also the problem that filament winding products that do not leave mandrels are not suitable for use as reinforcing tiJ in wheel rims (it is stated that increasing tiJ makes it easier for gas to pass through) and as gas or liquefied gas cylinders.

On the other hand, in order to make a metal mandrel lighter, it is easy to think of ways to reduce its wall thickness, but mandrels with small (thin) walls are difficult to make and, in some cases, extremely expensive. . Metal mandrels are also naturally heavier than plastic mandrels of the same thickness, and weaker than well-designed fiber-reinforced plastic composites when compared at the same weight.

Therefore, as a way to obtain a cheap and lightweight mandrel,
One solution is to develop and adopt a plastic mandrel with a small wall thickness. A preferable method for obtaining such a plastic mandrel is blow molding, for example.

In particular, it is known that blow-molded containers made of polyethylene terephthalate or the like exhibit extremely high strength even if the wall thickness is small due to the effect of stretching during molding.

However, mandrels with small wall thickness (particularly small wall thickness in the body) obtained by blow molding are soft regardless of the material they are made of, and are therefore unsuitable for use as molding mandrels in the filament wine tongue method because they become distorted during molding. be.

Furthermore, as a strength problem, the plastic mandrel has a smooth surface, making it difficult to wind the fibers evenly because the fibers are slippery during the filament winding process, and therefore it is difficult to align the fibers in a predetermined position. As a result, physical properties such as strength of the obtained molded product often fail to reach desired values.

Regarding strength, in the case of cylinders made using the filament Wine Tongue method, the reinforcing fibers are wound diagonally to the axis with square marks, so in some cases the pattern of the reinforcing fibers may be slightly distorted due to force being applied to the cylinder. There is a possibility of deviation. When force is applied in the axial direction due to internal pressure of the cylinder, the cylinder stretches in the axial direction, and the clogging force moves in the circumferential direction, causing the cylinder to easily deform when internal pressure is applied.

However, when a mandrel with a small wall thickness made of a material with low rigidity such as plastic is used, the inner cylinder, that is, the mandrel, is easily deformed, which exacerbates this problem, and in some cases may cause the problem of delamination of filament winding composite materials. It may also lead to.

Therefore, it is necessary to solve these problems together.

[Means for solving the problem] The present inventors have developed a small-walled plastic mandrel (
As a result of intensive research to solve the above-mentioned problems when manufacturing composite material cylinders using the filament winding method, we have developed a sufficiently light plastic mandrel and a composite material reinforced mH sheet. By creating a new lightweight mandrel that can secure the necessary and sufficient rigidity for filament winding, and combining this with the filament winding method,
The present invention has been completed by discovering that it is possible to manufacture a lightweight and useful composite material cylinder.

That is, the present invention provides a method for manufacturing a composite material cylinder, characterized in that the outer periphery of a plastic inner cylinder is covered with a reinforcing fiber sheet, and a fiber-reinforced plastic layer is formed thereon by a filament winding method. It is.

In the method of the present invention, a plastic inner cylinder with a small wall thickness is used as the inner cylinder of the composite material cylinder. Such an inner cylinder is preferably formed by blow molding.

In general, blow molding of plastic molding involves making a pipe of the plastic, closing one end, heating it, and expanding it mechanically and under pressure to form the desired shape. In the case of polyester, etc., a test tube-shaped intermediate called a preform is made, which is heated and then heated with air and air (or gas).
Expand it by blowing it into the desired shape. The wall thickness of intermediate bodies such as preforms is often about 2 to 5 tones,
The thickness of the molded product obtained is usually one shoe or less. In the case of a blow-molded product made of polyester such as polyethylene terephthalate, the area stretching ratio is approximately 10 times, taking into consideration the stretching effect, and the body portion is often 0.2 to 0.3 am+thick.

The material of the plastic inner cylinder that serves as the mandrel is selected depending on the contents of the cylinder. Generally, polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), polyamide (nylon 6, nylon 66, etc.), polyolefin, polyvinyl chloride, polycarbonate, AB
The material is selected from S resins, etc., and polyester and nylon are particularly preferred in the case of LPG. Due to the problem of gas permeability, it is also preferable to use a multi-layered material with a plastic having a low gas permeability.

For example, for carbon dioxide gas cylinders, it is preferable to interpose a thin layer of polyvinylidene chloride in the middle layer of a polyester mandrel.

Further, for the purpose of reducing gas permeability, the inner surface of the plastic inner cylinder may be fluorinated by using nitrogen gas containing fluorine as the blowing gas for blow molding.

Although this blow molded product has strength, it is extremely soft. Therefore, it is inappropriate to use it as it is as a mandrel for filament winding.To solve this problem, there is a proposal to pressurize fluid into the mandrel (for example, Japanese Patent Application Laid-Open No. 169226/1982), but There are other problems such as changes in the size of the mandrel during ejection. The present inventors attempted to solve this problem by wrapping at least the body of the mandrel with a reinforcing fiber sheet that also serves as circumferential reinforcement of the plastic inner cylinder that becomes the mandrel.

The reinforcing woven sheet may be pre-impregnated with plastic (resin), that is, prepreg, or may be wrapped only with a fiber sheet. Furthermore, plastic (resin) may be applied over it, or it may be applied in advance and then wrapped. Further, the plastic (resin) may or may not be cured. Alternatively, it may be semi-cured.

Reinforcement I to wrap around the mandrel! The fiber receipt material is the same as that used for filament winding, and in practice it is glass fiber or carbon fiber.

Examples include aramid fibers. It is preferable to match that used in filament winding, which will be described later.

Reinforcement! The form of the fiber sheet is unidirectionally aligned prepreg,
It can take any form such as a stack of these layers intersecting each other, a woven fabric, a non-woven fabric, etc.

The reinforcing fiber sheet may be wrapped around the entire surface of the plastic inner cylinder that becomes the mandrel, except for the nozzle part, but it is sufficient to wrap it only around the part that corresponds to the body of the mandrel. The reinforcing sheet may be wide enough to match the length of the mandrel body, or may be narrow in the form of a tape (in this case, it is wound spirally). In either case, the appropriate winding thickness is 0.5 to 2M.

In the method of the present invention, reinforcing fibers and plastic (resin) are molded thereon (on the outer periphery) by a filament winding method and hardened to form a fiber-reinforced plastic layer.

The reinforcing fibers used in the filament winding method of forming cylinders according to the method of the present invention may be general fibers used in this method and are not particularly limited in type, but in practice, glass fibers, carbon fibers, aramid fibers, etc. are used. . Glass fiber is most preferable from the viewpoint of balance between cost and physical properties.

The plastic (resin) to be attached to the fibers may be the plastic (resin) generally used in filament winding as described above, such as unsaturated polyester resin, epoxy resin, vinyl ester resin, etc. It may also be a thermoplastic resin. The temperature for post-processing, such as curing the plastic, is selected depending on the heat resistance of the polymer used to make the mandrel. In other words, the selection of plastic is made by taking into consideration the relationship between its curing temperature and the material of the mandrel.

The filament winding method can be dry or wet, and the winding pattern can be spiral,
Either polar type may be used. For low-pressure cylinders, since the filament winding is thin, polar winding may be preferable to suppress elongation. It is common to superimpose a hoop winding on top of the spiral or polar winding.

A composite material cylinder manufactured by the method described above is sufficient as a container for air 9w1 or other ordinary gases. However, in the case of combustible materials such as LPG, gas permeation problems may occur.To avoid this problem, a blow-molded plastic mandrel (which becomes the inner cylinder of the cylinder) is
It may be preferable to plate the plastic mandrel with metal, and it may also be preferable to cover the outside of the blow-molded plastic mandrel or the outside after sheet wrapping with a thin metal such as metal foil.

The metal foil used as needed is aluminum.

In addition to soot, copper, etc., anything that can be made into metal foil, such as gold and silver, can be used. Aluminum is particularly preferred from the viewpoint of gas barrier properties and cost balance.

FIG. 1 is a sectional view showing an example of a composite material cylinder produced by the method of the present invention. In the figure, (1) is a plastic inner cylinder formed by blow molding etc. (which becomes the mandrel for filament winding), (2 is a reinforcing fiber sheet layer wound around the body of the cylinder, and (3) is a spirally wound filament winding. layer, (4) is the nozzle of the cylinder, (5) is a metal foil (optional) to improve gas permeability, and (
6) is a hoop-wound filament winding layer which is the outermost layer of the cylinder.

The cylinder may further have its surface painted or covered with a thin plastic layer.

[Examples] Next, Examples of the present invention will be described in detail, but the present invention is not limited to these Examples.

Example 1 A test tube-shaped molded product (preform) was made using polyethylene terephthalate by an injection method. This was blow molded into a bottle shape. The diameter of the blow molding is 2
50m11. The weight was 650IllI11.

Apply epoxy resin on top of this (outer circumference) and use commercially available glass.
The fiber fabric was rolled up, secured with thread, and then coated with epoxy resin to harden it. The thickness of the rolled sheet was 0.4 mm.

Glass fiber 11i (E glass 4!I>), which is a glass fiber impregnated with epoxy resin, was spirally wound thereon at a winding angle of 13.6° using the filament winding method.The thickness of this layer was 1.2jem. And so.

Furthermore, the above epoxy resin-impregnated glass fiber was wound in a hoop shape only around the body. The thickness of this layer is 2.2a
It was set as m.

This actual droplet example could be successfully formed using the filament winding method. The composite material cylinder obtained by curing the resin has an internal pressure of at least 100% as a result of a water pressure test.
It was confirmed that it can withstand up to 9/ai.

Example 2 A mandrel was made by blow molding a polypropylene resin. The mandrel had a diameter of +50 m and a length of 300 m. Aluminum foil was wrapped around the entire surface of this, leaving the nozzle portion.

Glass in the body of this mantle! An IN cloth was impregnated with an unsaturated polyester resin and a prepreg was wound thereon, and a glass fiber impregnated with an unsaturated polyester resin was wound thereon at a winding angle of 30° using a filament winding method. On top of that, a hoop was wrapped only around the torso.

Good molding can be achieved using the filament winding method, and the thickness of the sheet (prepreg) part is 0.6. , the thickness of the filament winding part is 1.811+s for the spiral winding layer.
+, the hoop-wound layer was 2.4 aa+. The obtained cylinder had a structure as shown in FIG. 1, and as a result of a water pressure test, it withstood at least 100 KFI/cti.

Comparative Example A filament winding process was performed on the mandrel of Example 1 without wrapping the sheet. Although the film was wound at a winding angle of 1366°, it was difficult to wind it evenly, resulting in irregularities. After wrapping only one layer as in Example 1, only the body portion was wound with a hoop. The hoop winding was carried out by 20% of that in Example 1.

Although there were some problems with the appearance, the water pressure test showed that the weight was 85 kg/
It was destroyed at about cM.

[Effects of the Invention] According to the method of the present invention, a lightweight, inexpensive, beautiful composite material cylinder with excellent physical properties can be obtained. Since the cylinder manufactured by the method of the present invention has a relatively thin plastic mandrel, it is lighter than a composite material cylinder in which the mandrel is not wound on a metal mandrel and is not removed, and it is easy to wind, whereas the basic mandrel is soft and difficult to wind the filament as it is. Therefore, it has a beautiful finish and good physical properties.

Furthermore, due to the presence of the inner cylinder made of plastic nac and the ability to wind the filament uniformly and without any gaps, it has the advantage of significantly less gas permeation than a cylinder made only of composite materials.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a composite material cylinder according to the present invention. In the figure, (1) is a plastic inner cylinder, (
a is a reinforcing fiber sheet, (3) is a spiral-wound filament winding layer, (4) is a nozzle, (5) is a metal foil, and (6) is a hoop-wound filament winding layer. Patent Applicant: Teijin Co., Ltd. Courtesy: Patent Attorney: 1) Jun Fu,
i:”:”l]1.5 ,'ding\゛(1 -ni-

Claims (1)

[Claims] 1. A method for manufacturing a composite material cylinder, which comprises covering the outer periphery of a plastic inner cylinder with a reinforcing fiber sheet, and then forming a fiber-reinforced plastic layer thereon by a filament winding method. 2. The manufacturing method according to claim 1, wherein the plastic inner cylinder is blow molded. 3. The manufacturing method according to claim 2, wherein the inner surface of the plastic inner cylinder is fluorinated using nitrogen gas containing fluorine as the gas for blow molding. 4. The manufacturing method according to claim 1 or 2, wherein the plastic inner cylinder has a surface plated with metal. 5. The manufacturing method according to claim 1 or 2, wherein the plastic inner cylinder has its surface covered with a thin metal sheet. 6. The manufacturing method according to claim 1 or 2, wherein the reinforcing fiber sheet is wound around the part of the plastic inner cylinder that corresponds to the body. 7. The manufacturing method according to claim 1 or 6, wherein the reinforcing fiber sheet is a prepreg sheet. 8. The manufacturing method according to claim 1 or 6, wherein the reinforcing fiber sheet is a woven fabric. 9. Claim 1 in which the reinforcing fiber sheet is a nonwoven fabric
or the manufacturing method of paragraph 6. 10. The manufacturing method according to claim 1, wherein the surface of a plastic inner cylinder whose outer periphery is covered with a reinforcing fiber sheet is covered with a thin metal sheet, and a fiber-reinforced plastic layer is formed thereon by a filament winding method.