JP4318278B2 - Method for producing cylindrical fiber-reinforced rubber molded body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for producing a cylindrical fiber-reinforced rubber molded body, and more specifically, a cylindrical fiber-reinforced rubber having an inner rubber layer, a reinforcing layer, and an outer rubber layer, and having a strong reinforcement in the circumferential direction of the cylindrical body. process for producing a molded article related.
[0002]
[Prior art]
Flexible pipes such as flexible expansion joints and rubber joints are well known as cylindrical bodies that allow a high-pressure fluid to pass through and are displaced in a direction perpendicular to the axis of the cylindrical cylindrical fiber-reinforced rubber molded body. Such a flexible tube is generally composed of an inner rubber layer and an outer layer that come into contact with the liquid passing therethrough, and the outer layer has a reinforcing fiber layer and an outer rubber layer outside the inner rubber layer, and is reinforced when necessary. A ring-shaped or coil-shaped reinforcing metal layer (also referred to as a reinforcing body layer) or a woven fabric layer is provided on the outer surface of the outer rubber layer between the fiber layer and the outer rubber layer or between the inner rubber layer and the reinforcing fiber layer. . The reinforcing fiber layer is formed by laminating at least two layers of a so-called topping cord obtained by topping an unvulcanized rubber composition with a calender roll or the like on a bowl-like cord and then cutting the cord so that the cord has a predetermined angle with respect to the cutting direction. In addition, the cords of each layer are configured to form a predetermined angle.
[0003]
[Problems to be solved by the invention]
In recent years, a high-pressure liquid is sealed, or a gel-like resin, an elastomer, or a metal (lead, tin, etc.) that deforms relatively easily is sealed, and in a state perpendicular to the axis with a strong compressive stress applied. There is a need for a flexible tube that can be used as a displacing cylinder, for example, a vibration-isolating structure that is used as a central axis of seismic isolation rubber. When conventional flexible pipes are used for such applications, the fibers constituting the reinforcing layer are arranged in a bias shape, so that the pipe diameter expands due to the high internal pressure and the applied compressive stress, and the reinforcing fiber layer is destroyed. The content leaks and the function cannot be performed.
[0004]
In order to prevent the tube from being broken due to such an increase in internal pressure, the following method can be considered.
(1) A topping cord using a hook-shaped cord is arranged so that the fiber array is in the circumferential direction.
[0005]
(2) A metal coil reinforcing layer employed in a conventional flexible tube is provided.
[0006]
However, according to the method (1), the connecting portion of the topping cord is generated, and it is difficult to obtain a flexible tube that can withstand high internal pressure. In addition, when the metal coil reinforcing layer (2) is provided, if the tube inner diameter is the same, the outer diameter of the tube increases. For example, the tube cannot be inserted into a hole formed in the vibration isolating rubber, and the flexibility is lowered. Arise. Therefore, in view of the above-mentioned problems of the prior art, the object of the present invention is to provide a high breaking strength against a high internal pressure, a high flexibility with respect to displacement in a direction perpendicular to the tube axis, and a high productivity. , therefore it is to provide a production method capable of reducing a cylindrical fiber reinforced rubber molded body production costs.
[0010]
Furthermore, the characteristic configuration of the method for producing a cylindrical fiber-reinforced rubber molded body according to the present invention is that a first unvulcanized rubber layer constituting an inner rubber layer is formed on a mandrel, and this first unvulcanized rubber is formed. A reinforcing layer is formed by spirally winding a continuous coated reinforcing wire coated with unvulcanized rubber on the surface of a single wire or stranded wire on the layer so as to be closely adjacent to each other , and further reinforcing A second unvulcanized rubber layer constituting the outer rubber layer is formed on the layer to form an unvulcanized molded body, and the unvulcanized molded body is heated and vulcanized.
[0011]
According to the method for producing a cylindrical fiber reinforced rubber molded body with this configuration, a reinforcing layer having a strength corresponding to the application can be obtained by selecting a material of the reinforcing wire , and the fracture strength against a high internal pressure is large. A cylindrical fiber reinforced rubber molded body having a high flexibility with respect to displacement in a direction perpendicular to the tube axis can be produced at a high productivity and therefore at a low production cost without requiring any particularly complicated processing steps. I was able to.
[0012]
One continuous coated reinforcing wire coated with unvulcanized rubber can be easily produced continuously using an extruder. Also, by continuously using a single coated reinforcing wire coated with unvulcanized rubber produced using an extruder, the winding interval and angle of the reinforcing wire can be arbitrarily set according to the purpose. In addition, the adhesion between the inner rubber layer / reinforcing layer and the reinforcing layer / outer rubber layer becomes stronger and more stable than when a conventional topping cord is used.
In the reinforcing wire, one fiber per layer is continuously wound in a coil shape, but a plurality of such fiber layers may be formed. In the case of a two-layer structure, it is preferable that the spirals of the first and second layer reinforcement lines are in opposite directions because a well-balanced reinforcement layer can be formed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a topping process in which an unvulcanized rubber composition is coated on a reinforcing wire using an extrusion device. In this example, a cord is used as a reinforcing wire. Therefore, one continuous coated reinforcing wire coated with an unvulcanized rubber composition is referred to as a topping monocord.
[0014]
A die 4 is attached to the tip of the cylinder portion 2 of the extruder 10, and a raw material cord 6 unwound from a reel or the like (not shown) is fed to the die 4, where unvulcanized rubber is fed. The composition is coated and delivered as a topping monocode 8. As the raw material cord 6, either a stranded wire or a single wire can be used. In the following, an example using a monocord (stranded wire) will be shown.
[0015]
When laminating the delivered topping monocord 8 on a mandrel, the work that is the object to be laminated is moved by a computer so that the fiber arrangement satisfies design conditions such as a predetermined direction, length, and angle. Is preferred.
[0016]
The cross-sectional shape of the topping mono-cord 8 is appropriately set depending on the application and is not particularly limited, and a specific example is shown in FIG. FIG. 2A shows an example having a cross section close to a rhombus or parallelogram, FIG. 2B shows a square, FIG. 2C shows a circle, and FIG. 2D shows a trapezoid. In either case, the raw material cord 6 is covered with an unvulcanized rubber composition 7. The thickness of the unvulcanized rubber composition layer is appropriately set according to the set code interval. Among these, the topping monocord having a circular cross section shown in FIG. 2 (c) has an excellent balance and is not wasteful because it is uniformly coated with an unvulcanized rubber composition around the monocord, and is continuous with the mandrel. As a result, it is possible to form a cylindrical body whose inner and outer surfaces are substantially parallel to each other, so that it can be displaced without difficulty with respect to the deformation action in the direction perpendicular to the tube axis, and is also great with respect to the expansion action in the circumferential direction. A cylindrical fiber-reinforced rubber molded body that exhibits tensile resistance and is difficult to deform is preferable.
[0017]
A method for producing a cylindrical fiber-reinforced rubber molded body using the topping monocord 8 and forming a reinforcing layer on the mandrel will be described below.
[0018]
FIG. 3 shows an example of a cylindrical fiber-reinforced rubber molded body of the present invention, which is one type of reinforced rubber flexible tube, and contains a high-pressure fluid, a swollen gel-like resin, lead, tin, etc. It is used for applications in which deformation due to stress having a component in a direction perpendicular to the axis of the tube occurs in a state where a relatively easily deformable material is enclosed. In such a flexible tube, the topping cords are arranged spirally around the inner rubber layer, that is, in a radial direction that is orthogonal to the axis of the tube. In such a flexible tube, it is particularly important that the code arrangement is highly uniform, and if there is a non-uniform portion, the tube may be damaged by a high internal pressure at that portion, and the internal filling may leak. Occurs. When the conventional topping cord is used, the joint portion is inevitably generated, and it is difficult to ensure the uniformity of the cord interval, there is a problem in strength, and improvement is desired. Such problems can be reliably improved.
[0019]
In the cylindrical fiber-reinforced rubber molded body, the topping monocord 8 is spirally wound on an unvulcanized rubber composition layer 17 serving as an inner rubber layer formed on the mandrel 15 as shown in FIG. . The topping monocord is wound, for example, by supplying the topping monocord fed from the extrusion apparatus shown in FIG. 1 to the mandrel, and rotating the mandrel at a predetermined rotational speed, at a predetermined speed parallel to the axis. This can be done by moving.
[0020]
By this method, the reinforcing layer has no joint portion, and the uniformity of the cord interval can be improved. As a result, as shown in FIG. 4 (a mandrel is omitted), a tubular reinforcing rubber molded body having high strength uniformity can be obtained as compared with the case where a conventional topping cord is used.
[0021]
In the cylindrical fiber-reinforced rubber molded body shown in FIG. 3, a reinforcing layer having a two-layer structure may be formed by winding a second layer cord on the reinforcing layer in a spiral direction opposite to the illustrated cord. It may be further laminated repeatedly to have a structure of two or more layers. Finally, an outer rubber layer is further coated on the reinforcing layer and vulcanized to obtain a formed body.
[0022]
The topping monocord according to the present invention is continuously used for processing, but may be partially cut if necessary for processing. Nevertheless, the end face where the cord is exposed is less than when the conventional topping cord is used.
[0023]
You may comprise a reinforcement layer combining the reinforcement layer by the topping monocord of this invention, and the conventional saddle-like topping cord. The reinforcement by the conventional hook-shaped topping cord may be partial.
[0024]
Among the raw materials used in the present invention, as the unvulcanized rubber composition forming the topping cord, a known rubber composition is appropriately selected according to the use. The inner rubber layer constituting rubber and the outer rubber layer constituting rubber may be the same rubber material or different rubber materials. In flexible pipes, flexible pipe joints, rubber hoses, etc., a rubber material having excellent durability is usually used for the outer layer, and a rubber material having characteristics corresponding to the fluid passing through the inside is used for the inner layer. It is preferable to use a thermoplastic resin tube such as a polytetrafluoroethylene tube or a polyethylene terephthalate tube, a thermoplastic elastomer, or the like for the contact surface with the fluid.
[0025]
For the outer layer of the reinforcing layer, known reinforcing members such as steel rings and coiled reinforcing metal fittings may be used as necessary, and a reinforcing woven fabric layer for preventing wear is provided on the outermost layer. Also good. In a tubular molded body such as a flexible joint, a connecting portion such as a flange can be provided as necessary.
[0026]
As the topping cord constituting the reinforcing layer, known fibers used as the reinforcing layer in the technical field can be used without limitation. Specifically, polyester fibers such as polyethylene terephthalate and polyethylene naphthalate, polyamide fibers such as nylon 6 and nylon 66, organic fibers such as high-strength fibers such as aramid fibers and PBO fibers, steel cords, glass fibers, carbon fibers, etc. Is exemplified. Among these reinforcing wires, it is preferable to use steel cords and high strength fibers in the cylindrical fiber-reinforced rubber molded body of the present invention. By using such a fiber, a cylindrical fiber-reinforced rubber molded product that can withstand higher internal pressure can be obtained.
[0027]
The fiber may be a monofilament or a multifilament, but a multifilament yarn is preferably used as a cord from the viewpoint of excellent strength and flexibility.
[0028]
The fiber used as the cord is preferably subjected to a treatment for improving the adhesiveness in advance as necessary. For example, a polyester fiber or a polyamide fiber is subjected to a resin treatment such as a phenol resin treatment or a glass fiber. Examples of suitable coatings include treatment with coupling agents such as silane coupling agents and titanium coupling agents, and brass plating for steel cords.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a topping process for forming a reinforcing layer of a cylindrical fiber-reinforced rubber molded body according to the present invention. FIG. 2 is a cross-sectional view showing an example of a cross-sectional shape of a topping monocord. FIG. 4 is a perspective view for explaining a method for producing a cylindrical fiber-reinforced rubber molded body according to the invention. FIG. 4 is a half sectional view of a cylindrical fiber-reinforced rubber molded body in which topping monocords are laminated.
8 Reinforcing layer 15 Mandrel 17 Inner rubber layer

Claims (1)

The first unvulcanized rubber layer constituting the inner rubber layer is formed on the mandrel, and the surface of the single wire or the stranded wire is coated with the unvulcanized rubber on the first unvulcanized rubber layer. One coated reinforcing wire is spirally wound so as to be adjacent to each other to form a reinforcing layer, and a second unvulcanized rubber layer constituting an outer rubber layer is further formed on the reinforcing layer. A method for producing a cylindrical fiber-reinforced rubber molded body, which is an unvulcanized molded body, and the unvulcanized molded body is heated and vulcanized.

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