JPH0669708B2 - Method and apparatus for embedding reinforced yarn in synthetic resin tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a molding apparatus for molding a synthetic resin pipe in which reinforcing yarns (warp yarns) for reinforcement are integrally embedded in the axial direction.

(Prior Art) Conventionally, an apparatus described in Japanese Utility Model Publication No. 56-517 has been proposed as a molding apparatus for a synthetic resin tube in which reinforcing threads are integrally embedded in the axial direction.

This device is provided with a plurality of mounting holes from the rear of an extruder equipped with an extrusion die having an extrusion passage through which a tubular molten resin is extruded, to the inside of the extrusion passage of the extrusion die. It has a structure in which a guide tube of elongated reinforcing yarn is detachably penetrated through the attachment hole so that the tip of the guide tube is located inside the extrusion passage in the attachment hole.

Then, as a result of this, the supply of the reinforcing yarn is guided along with the flow of the molten resin in the extrusion passage, and the reinforcing yarn supplied from the guide tube is introduced from the rear of the extruder along the axial direction to the inside of the thickness of the molten resin. It is extruded from the extruder together with the molten resin in the embedded state, and is cooled and cured by the cooler while being wound by the winder that pulls the molten resin, and the reinforcing yarn is integrally embedded in the axial direction of the synthetic resin pipe. It was done like this.

(Problems to be Solved by the Invention) In the above-described conventional apparatus, a perforating process for forming a mounting hole for providing a guide tube so as to face the inside of the extrusion passage of the extrusion die from the rear of the extruder is performed. It must be applied to the extruder mold itself. Moreover, when the mounting hole is formed in the die itself of the extruder in this way, when the molten resin is extruded, the molten resin to be pumped out leaks from the mounting hole formed in the extruder die and flows backward. Therefore, in order to cope with such a situation, precise processing is inevitably required so that the mounting hole and the guide tube are fitted in an extremely dense state, or a resin is used in the mold. There is a need for a seal structure to prevent backflow of the.

Further, the guide tube has a length extending from the rear of the extruder into the extrusion passage of the extrusion die over substantially the entire length of the extruder die, and maintenance is extremely difficult when the reinforcing yarn is cut in the guide tube during molding. It has the following problem. Moreover,
Since the tip end is located in the extrusion passage of the extrusion die, there is a possibility that the portion substantially interferes with the smooth flow of the molten resin in the extrusion passage.

In particular, when the number of reinforcing yarns embedded in the synthetic resin pipe is increased, the number of reinforcing yarns increases in the structure in which such a pipe-shaped guide tube is positioned so as to face the extrusion passage. As a result, the number of guide tubes arranged increases, which not only complicates the piping of the guide tubes, but also makes the pipe shape in the very thin and narrow extrusion passage for molding the synthetic resin pipe. The proportion of guide tubes in the
By narrowing the passage or the like, it becomes more difficult for the molten resin to which the resin pressure necessary for extrusion molding is applied to flow in the extrusion passage.

The present invention is to improve the conventional apparatus having such a problem, without performing any processing on the die itself of the extruder, and even if the number of embedded reinforcing yarns increases, the molten resin It is an object of the present invention to embed a reinforcing yarn at a predetermined position in the axial direction in the thickness of the molten resin and integrally extrude it without hindering the smooth flow of the molten resin.

(Means for Solving the Problems) The technical means of the present invention, which is taken to solve the above problems, is to communicate the circumferential direction of the extrusion die with the extrusion passage in the interior thereof to form a supply passage for guiding the reinforcing yarn. An embedding protrusion ridge that restricts the embedding depth of the reinforcing yarn is formed so as to project along the entire circumference of the extrusion passage between the outlet downstream side of the extrusion passage of the supply passage and the outlet of the extrusion passage. In addition, a supply unit for supplying the reinforcing yarn from the circumferential direction of the extrusion die to the supply passage is provided near the extruder.

(Operation) According to the above means, the reinforcing yarn supplied from the supply unit is guided in the supply passage in the circumferential direction of the extrusion die and faces the extrusion passage,
Here, it becomes integral with the molten resin flowing in the passage. In the extruding passage, the reinforcing yarn is guided to the outlet side of the extruding passage by being guided by the embedded protruding ridge formed to project along the entire circumference of the extruding passage between the opening of the supply passage and the outlet of the extruding passage. By being bent, the protrusion height of the embedding protruding ridge regulates the embedding depth within the thickness of the molten resin, and is extruded together with the molten resin while being embedded integrally at a predetermined position within the resin thickness from the exit of the extrusion passage. And pulled by the winder.

(Example) Hereinafter, an example of a reinforcing-fiber embedding molding apparatus for a synthetic resin pipe according to the present invention will be described with reference to the drawings.

In the embodiment shown in FIGS. 1 to 3, the extruder 1 having the extrusion screw 11 inside and the extrusion die 12 on the outlet side is used, and the inside of the extrusion die 12 has a cylindrical shape. The extrusion passage 13 provided and an air supply port formed inside the extrusion passage 13.
14 and are provided.

The molten resin A is made of a synthetic resin material having good elasticity such as polyvinyl chloride. In the extruder 1, the molten resin A is pressed by the extrusion screw 11 and heated by an appropriate heating tool to be molded. Then, the molten resin A flows from the inside of the extruder 1 into the extrusion passage 13 and is extruded in a tubular shape out of the extruder 1. The molten resin A thus extruded in a tubular shape from the extruding passage 13 is applied with an internal pressure by the air supply from the air supply port 14 to maintain its shape, and through a cooler such as a water tank (not shown). Similarly, it is pulled by a winder (not shown) and wound up.

In the extrusion die 12, a supply passage 21 for integrally embedding the reinforcing yarn B inside the molten resin A flowing in the extrusion passage 13,
An embedded projecting ridge 22 is provided.

The supply passage 21 is composed of fine pores which are formed by communicating with the extrusion passage 13 inside the extrusion die 12 from the circumferential direction thereof, and guides and supplies the reinforcing yarn B into the extrusion passage 13 through which the molten resin A flows. A plurality of reinforcing yarns B are embedded in the molten resin A.

The embedded projecting ridge portion 22 is a small projecting ridge projectingly formed in the extrusion passage 13, and is adjacent to the opening in the extrusion passage 13 of the supply passage 21 on the downstream side of the passage, that is, on the outlet side. And the outlet of the extrusion passage 13 are provided along the entire circumference of the extrusion passage 13 so as to project into the extrusion passage 13. The embedded protruding ridge 22 is guided and supplied from the supply passage 21 into the extrusion passage 13, and the reinforcing yarn B bent along the flow direction of the molten resin A in the passage 13 is replaced with the meat of the molten resin A. The embedding depth of the reinforcing yarn B is regulated so that the embedding is performed at a predetermined position inside the thickness.

In the vicinity of the extruder 1, a supply unit 23 for supplying the reinforcing yarn B to the supply passage 21 of the extrusion die 12 is provided.

The supply unit 23 is provided in the vicinity of the extruder 1 and includes a plurality of bobbins 23A around which the reinforcing yarn B is wound and a frame 23B that rotatably supports the bobbins 23A. The reinforcing yarns B are supplied to the supply passages 21 from the circumferential direction of the mold 12, respectively.

A plurality of the supply passages 21 are provided at equal intervals in the circumferential direction of the extrusion die 12, and correspondingly, the bobbin 23 is provided.
The same number of A is provided.

By means of the supply passage 21 and the embedded protruding ridge 22 provided in the extrusion die 12 and the supply portion 23, the molten resin A flowing inside the extrusion passage 13 with respect to the extruder 1 is provided. Reinforcement thread B
To constitute the supply means 2 of the reinforcing yarn B for embedding.

By thus providing the extruder 1 with the supply means 2 for the reinforcing yarn B, it is possible to process only the periphery of the extrusion die 12 without performing any processing on the die itself of the extruder 1 and thereby the extrusion passage by the extruder 1. With respect to the molten resin A flowing in 13, the reinforcing yarns B introduced into the supply passages 21 from the respective bobbins 23A are bent along the embedded protrusions 22 in the tensile direction of the molten resin A, that is, the axial direction. It can penetrate inside the wall.

Then, the reinforcing yarn B that has entered the molten resin A is extruded together with the molten resin A from the extrusion die 12 and pulled (the introduction of the reinforcing yarn B from each bobbin 23A is continued) to be cooled and hardened, so that the molten yarn is melted. The reinforcing yarn B is embedded along the axial direction inside the thickness of the resin A and is integrally molded. Therefore, the reinforced yarn B is attached to the ordinary synthetic resin pipe molding process.
Since the embedding step can be performed, the manufacturing cost can be reduced without requiring manufacturing labor.

In this embodiment, since a plurality of supply paths 21 are provided at equal intervals in the circumferential direction of the extrusion die 12, a plurality of reinforcing yarns B are embedded in the molten resin A in the axial direction at equal intervals. The reinforcing yarn B serves as a core in the circumferential direction of the molten resin A extruded from the extrusion passage 13, and the tubular shape retention of the molten resin A is effectively achieved by the synergism with the air supply from the air supply port 14 described above. Done. Moreover, the arrangement of the plurality of reinforcing yarns B in the circumferential direction of the molten resin A prevents the tension of the molten resin A from being applied to the molten resin A by the winding machine, and the tensile speed of the molten resin A (that is, the molding speed). ) Has a stabilizing effect.

Further, when the contact surface of the embedding protrusion ridge 22 along which the reinforcing yarn B is inserted to penetrate the molten resin A with the reinforcing yarn B is formed into a curved surface shape, friction during embedding supply of the reinforcing yarn B is reduced. As a result, the reinforcing yarn B is prevented from being damaged and the resistance is reduced, so that the reinforcing yarn B can be introduced and embedded smoothly. In addition, the embedding depth of the reinforcing yarn B can be adjusted by adjusting the projecting height of the embedding protruding ridge 22. If the protruding height of the embedding protruding ridge 22 is made different, Each embedding depth of the reinforcing yarn B can be randomized or can be arranged on a plurality of concentric circles.

Further, in the drawing, the supply portion 23 of the reinforcing yarn B is installed on the tension side of the molten resin A, but it may be installed in another place as long as it is near the extruder 1. The perforation angle, the perforation direction and the like from the circumferential direction of the extrusion die 12 of 21 are set in consideration of smoothness and efficiency of introduction of the reinforcing yarn B.

As the material of the reinforcing yarn B, polyamide such as nylon, polyester such as Tetoron, other polyurethane,
Examples of usable materials include synthetic fibers such as polyurea, polypropylene, vilarone and acrylic, and natural fibers such as hemp, cotton and silk. That is, any material can be used as long as it has a certain level of strength, heat resistance and the like, and has a reinforcing property to the synthetic resin.

The synthetic resin pipe 3 manufactured by such a molding device is
As shown in FIG. 4, it has a structure in which the reinforcing yarn B is integrally embedded inside the wall thickness, and the wall thickness is not a layered structure such as the inner tube and the outer tube as in the past, but a single uniform thickness. Since the structure is made of a material, the reinforcing yarn B will not be displaced by the action of tensile force, twisting force, compression force, etc.
The advantage of the synthetic resin pipe in which the reinforcing yarn is embedded in the axial direction that the extension and the twist are prevented and the compressive strength is improved is retained, and the durability is improved.

In addition to the above-described embodiment, if the punching position of the feed path 21 in the circumferential direction of the extrusion die 12 is changed, the arrangement of the reinforcing yarns B in the circumferential direction is not evenly spaced but is partially offset. The synthetic resin pipe having various structures, such as a synthetic resin pipe having the above structure, can be selected according to the purpose of use.

(Effects of the Invention) Since the molding apparatus of the present invention is configured as described above, it has the following effects.

Reinforcing yarn embedded integrally in the thickness of the molten resin extruded by the extruder is processed only on the extrusion die provided on the exit side of the extruder to process the extrusion die itself. It is possible to supply guidance without applying it.

Therefore, in the conventional apparatus, there is no fear of molten resin backflow or the like which is a concern when a passage is bored in the die itself of the extruder and a tube for guiding the reinforcing yarn is arranged.

In the extrusion die itself, a guide tube or the like for guiding the reinforcing yarn into the extrusion passage is not provided so as to pass through the entire circumference of the extrusion passage between the opening in the extrusion passage of the supply passage and the outlet of the extrusion passage. It is possible to guide the reinforcing yarn supplied from the supply passage into the extrusion passage so as to be embedded in a predetermined position within the thickness of the molten resin by the configuration in which the embedded protrusion is formed to project. Moreover, it does not substantially obstruct the flow of the molten resin in the extrusion passage.

Therefore, the structure for embedding the reinforcing yarn at a predetermined position is extremely simple, and even if the number of the reinforcing yarns increases, only the reinforcing yarns are exposed in the molten resin flowing in the extrusion passage. As the number of reinforcing pipes increases with the number of reinforcing yarns, there is no problem that the tip of the guiding pipe decreases the flow area of the passage and further hinders the flow of the molten resin. Regardless of the number of reinforcing yarns, it is possible to mold a synthetic resin pipe in which the reinforcing yarns are constantly embedded at a predetermined position within the thickness of the molten resin with a stable resin pressure.

The supply passage for guiding the reinforcing yarn into the molten resin is provided so as to communicate with the internal extrusion passage from the circumferential direction of the extrusion die provided at the exit side of the extruder, and since it is substantially short, It is possible to confirm the supply state of the reinforcing yarn together with the molding state of the molten resin in which the reinforcing yarn extruded from the extrusion mold is embedded, and it is also possible to discover when the reinforcing yarn is cut during molding. Fast and extremely easy to maintain.

Since the device of the present invention has a structure in which only the extrusion die of the extruder is improved, only a part of the existing extruder, that is, the extrusion die can be easily modified and configured, and the device design and manufacturing cost are reduced. It can be reduced and the existing device can be effectively used.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of a reinforced yarn embedding molding apparatus for a synthetic resin pipe according to the present invention, FIG. 2 is an enlarged cross-sectional view of an essential part of FIG. 1, and FIG. 3 is FIG. FIG. 4 is a cross-sectional view taken along line XX of FIG. 4, and FIG. A ... Molten resin, B ... Reinforcing yarn 1 ... Extruder, 3 ... Synthetic resin tube 12 ... Extrusion mold, 13 ... Extrusion passage 21 ... Supply passage, 22 ... Embedded protrusion 23 ... Supply passage

Claims (1)

[Claims] 1. An extruder equipped with an extrusion die having an extrusion passage through which a tubular molten resin is extruded, the winding machine pulling the molten resin extruded from the extruder, and the extruder. And a cooling machine that is installed between the winder and cools and cures the pulled tubular molten resin, and supplies the reinforcing yarn inside the molten resin that flows in the extrusion passage of the extrusion die together with the molten resin. In a molding device for a synthetic resin pipe in which reinforcing fibers are integrally embedded along the axial direction by extrusion, in a peripheral direction of the extrusion die, a supply for reinforcing yarn communication is provided by communicating with an internal extrusion passage. An embedding protuberance that pierces a passage and regulates the embedding depth of the reinforcing yarn along the entire circumference of the extruding passage between the downstream side of the opening in the extruding passage of the supply passage and the outlet of the extruding passage. Of the extrusion die in the circumferential direction near the extruder. Reinforcing yarns embedded molding apparatus of the synthetic resin tube characterized in that a supply unit for supplying the reinforcing yarns to the supply passage.