JPH1071639A - Production of tubular member and mold therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously mold a tubular member excellent in strength and rigidity efficiently reinforced in its peripheral direction by a reinforcing material by suppressing the rotation of the reinforcing material mixed tubular member extruded from a mold and almost uniformly orienting the reinforcing material in the peripheral direction of the tubular member and to dispense with the use of complicated and expansive equipment such as a cooling machine, a taking-over machine or a cutting machine in a process on and after the mold to extremely reduce equipment cost. SOLUTION: A tubular member is produced by a method wherein a mixture of a reinforcing material and a thermoplastic resin is passed through the annular passage 3 between inner and outer molds 1, 2 and molded into a tubular shape so as to receive shearing force in a rotary direction from the driving rotary mold part rotated by a drive means during this passage to form a tubular molded object wherein the reinforcing material is oriented in a peripheral direction and the tubular molded object is subsequently passed through the passage part corresponding to the non-rotary mold part provided on the downstream side in the resin extrusion direction to be extruded from a passage outlet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a tubular body reinforced by a reinforcing material, and a mold for producing a tubular body.

[0002]

2. Description of the Related Art Conventionally, in order to increase the strength of a synthetic resin tubular body, a fibrous reinforcing material has been mixed.

However, according to the conventional method, since the fibrous reinforcing material is oriented in the extrusion direction, the fiber is reinforced in the extrusion direction, that is, in the longitudinal direction of the tubular body, but is not reinforced in the circumferential direction of the tubular body. There was a disadvantage.

In order to solve such a drawback, for example, as described in Japanese Utility Model Application Laid-Open No. 61-71421, a nipple (inner die) and a die (outer die) provided coaxially with the nipple are disclosed. And a die for manufacturing a tubular body in which one of a nipple and a die is rotationally driven.

[0005]

However, in a conventional method for manufacturing a tubular body using such a mold for manufacturing a tubular body, a reinforcing material mixed in a tubular body extruded from the mold is used. Since some fibers are oriented not only in the longitudinal direction of the tubular body but also in the circumferential direction, the fibers are reinforced not only in the longitudinal direction but also in the circumferential direction of the tubular body, but are extruded from the mold for manufacturing the tubular body. Since the tubular body is rotating,
There is also a problem that the take-up device for taking the tubular body also needs to rotate, and the structure of the take-up device is complicated and expensive.

The present invention has been made in view of the problems in the above-mentioned conventional method of manufacturing a tubular body, and an object of the present invention is to provide an annular flow path (hereinafter referred to as an annular flow path) having a cross section of a mold. In the molding including the step of rotating the synthetic resin mixed with the reinforcing material flowing in the inside, the rotation of the tubular body extruded from the mold can be suppressed, and the reinforcing material is almost uniformly oriented in the circumferential direction of the tubular body. A tubular body can be molded, a tubular body excellent in circumferential strength and rigidity reinforced efficiently in the circumferential direction by a reinforcing material can be continuously formed, and the tubular body extruded from the mold is Because the rotation is suppressed, in the process after the mold, there is no need to use complicated and expensive equipment for a cooling machine, a take-off machine, a cutting machine, etc., and the equipment cost is very low. Method and tubular body manufacture In the attempt to provide a mold.

[0007]

In order to achieve the above-mentioned object, a method for producing a tubular body according to the present invention comprises the steps of: forming a mixture containing a reinforcing material and a synthetic resin into an annular shape of a mold connected thereto by an extruder; A part of at least one of an inner mold and an outer mold that is introduced into the flow path and forms an annular flow path is rotated by a driving unit around a rotation axis extending in the same direction as the resin extrusion direction. In addition to the provision of the drive rotary mold part, a non-drive rotary mold part that is not rotated by the drive means but is capable of slightly free rotation is extended downstream of the drive rotary mold part in the resin extrusion direction, and the non-drive rotary mold part is provided. The outlet of the annular flow path is provided in advance, and the mixture is formed into a tubular shape so as to pass through the annular flow path and receive a shearing force in the direction of rotation approximately from the driving rotary mold portion during the passage, thereby strengthening the mixture. The material forms a tubular molded body oriented in the circumferential direction. The tubular molded body, after passing through a channel portion corresponding to the non-driven rotary part of the annular channel, is characterized in that extruded from the annular flow path outlet.

In the above-mentioned method for producing a tubular body, a fibrous reinforcing material is used as a reinforcing material, and a thermoplastic resin is used as a synthetic resin.

In the method for manufacturing a tubular body, at least a part of the flow path portion corresponding to the non-drive rotary type portion which is not rotated by the drive means is replaced with the flow path portion corresponding to the drive rotary type portion rotated by the drive means. Cooler than
It is preferable that the tubular molded body is cooled near the outlet in the annular flow path and then extruded from the outlet.

Further, in the above, at least a part of the non-drive rotary mold portion provided on at least one of the inner mold and the outer mold is provided with a convex portion protruding toward the annular flow path, so that the annular flow path is provided. A channel portion narrower than the other portion is formed in the channel, and the mixture is passed through the annular channel, and a tubular portion is subjected to a shearing force in a substantially rotational direction from the driving rotary portion during the passage. Forming a tubular molded body in which the reinforcing material is oriented in the circumferential direction, and then, after passing this tubular molded body through a narrow flow path portion in the annular flow path, extruding from the annular flow path outlet. ,preferable.

Further, in the mold for manufacturing a tubular body according to the present invention, the annular flow path is constituted by an inner mold and an outer mold, and at least one of the inner mold and the outer mold has a resin extrusion direction. A drive rotary type part is provided which is rotated about a rotary shaft extending in the same direction as the center and is rotated by a drive means. It is characterized in that the driving rotary mold part is extended and the outlet of the annular flow path is provided on the non-driving rotary mold part side.

In the above-mentioned mold for manufacturing a tubular body, at least one of the inner mold and the outer mold is provided with a cooling means in a flow path portion corresponding to the non-driven rotary mold portion of the annular flow path. ,preferable.

Further, in the mold for manufacturing a tubular body according to the present invention,
At least a part of the non-drive rotary type portion is provided with an annular or spiral convex portion protruding toward the annular flow path, and a flow path portion narrower than other portions is formed in the annular flow path. However, in order to achieve the object more accurately, it is preferable.

Here, the annular or helical projection is not necessarily required to be continuous. In other words, if the mixture of the synthetic resin and the reinforcing material has a function capable of applying a shearing force and extruding these in the extrusion downstream direction,
It can be discontinuous.

[0015]

According to the method and the mold of the present invention, a mixture containing a reinforcing material and a synthetic resin is extruded from an extruder at a temperature not lower than the melting point or the softening temperature of the resin, and the driving rotation of the annular flow path in the mold is performed. Pass through the channel corresponding to the mold.

At this time, the mixture is influenced by the shearing force due to the rotation of the inner or outer drive rotary mold part, and the orientation of the reinforcing material in the circumferential direction of the tubular body is promoted.

The mixture having passed through the flow path portion corresponding to the drive rotary type portion passes through the flow path portion corresponding to the non-drive rotary type portion extending in the downstream direction of the flow path, where it is rectified and further necessary. Accordingly, by cooling at least a part of the flow path portion corresponding to the non-driving rotary type part from the flow path part corresponding to the driving rotary type part, the mixture in a molten state is appropriately solidified, and The orientation can be easily adjusted to a desired degree. In this way, from the mold outlet, which is the terminal flow path of the annular flow path, the reinforcing material oriented in the circumferential direction is provided and the rotation is reduced.
A suppressed tubular body can be formed.

The cooling of the tubular body extruded from the mold must be carried out at least in the drawing step to a temperature at which the shape of the tubular body and the dimensions of the inner and outer diameters do not change plastically.
Preferably, it is desirable to cool to ambient temperature (outside air temperature).

Further, a convex portion protruding into the annular flow path is provided on the non-drive rotary mold portion of the mold to form a flow path portion narrower than the other portions, so that a narrow flow due to the convex portion is formed. When the molten resin passes through the road portion, the rotation of the tubular body is further suppressed by the so-called braking effect, and the tubular body is molded in a state where it does not rotate further, and is efficiently and sufficiently reinforced in the circumferential direction by the reinforcing material. A tubular body having excellent circumferential strength and rigidity can be manufactured.

Examples of the means for cooling the tubular body include a method of passing the product through a refrigerant in a water tank or the like, a method of applying cool air to a blower or the like, a method of passing the product through a cooling mold through which the refrigerant flows, and the like. It is appropriately selected according to the dimensions of the product and the production line.

As the extrusion method in the present invention, any conventionally known method may be adopted, for example, a single screw extruder or a twin screw extruder is used.

As a method of picking up the cooled product,
A conventionally known arbitrary method may be adopted, and for example, a belt type take-up machine, a caterpillar type take-up machine, a roll type take-up machine, or the like is appropriately used.

In the present invention, the synthetic resin which is a raw material for production is not particularly limited.
Examples include ABS resin, fluorine resin, acrylic resin, polyethylene resin, polypropylene resin, vinyl chloride resin, polycarbonate, polystyrene, polyurethane, and the like, and modified resins thereof, or melt-moldable resins such as blend resins and alloy resins.

Examples of the reinforcing material mixed in the synthetic resin include glass fibers, carbon fibers, metal fibers, organic fibers such as ultrahigh molecular weight polyethylene fibers, and inorganic fibers such as ceramic fibers.

In addition, a liquid crystal polymer which can improve the strength in the direction when it is oriented, for example, a liquid crystal polymer which becomes a fibrous reinforcing material when subjected to shearing in a mold can be used. Glass fibers are advantageous from the viewpoint of handling.

As a reinforcing material which is easily molecularly oriented, a wholly aromatic liquid crystal polyester or a semi-aromatic liquid crystal polyester which is a liquid crystal polymer can be cited, and these can be easily oriented in the flow direction by a shearing force or an elongating force applied during molding. I do.

As the form of the reinforcing material to be mixed, a monofilament-like material such as milled fiber or cut fiber may be used as it is, a chopped strand in which some fibers are bundled, or a roving-like continuous fiber. good.

The mixing of the reinforcing material and the synthetic resin is achieved in an extruder after being dry-mixed with a mixer such as a tumbler, or a reinforcing material other than the main raw materials is supplied from the middle of the extruder and is fed into the extruder. May be achieved. Alternatively, pre-mixed pellets manufactured using a land die or the like may be used.

The fibers may be those to which a surface treatment agent or a binder is appropriately added according to the thermoplastic resin to be mixed.

The shape of the reinforcing material to be mixed into the synthetic resin may be a continuous fiber such as glass fiber cut to an appropriate length, or a so-called whisker-like shape.

The length of the reinforcing material is not particularly limited, but preferably has an aspect ratio (fiber length / fiber diameter) of 1 or more.

If the aspect ratio is less than 1, the reinforcing effect by the fiber may not be exhibited.

When a short fiber of glass fiber is used as the reinforcing material, the aspect ratio is preferably 1000 or less. If the aspect ratio exceeds 1000, the fiber is cut by a screw shaft of an extruder to reduce the length. There is a possibility that a worthy reinforcement effect cannot be expected.

The fiber diameter is preferably about 1 to 100 μm, and the fiber length is preferably about 1 μm to 100 mm.

The mixing of the reinforcing material and the synthetic resin is achieved in an extruder after being dry-mixed with a mixer such as a tumbler.

In some cases, mixed pellets formed using a strand die or the like may be used.

The mixing ratio of the reinforcing material to the synthetic resin is within a range in which the whole composition can be molded in the following extrusion step, and the ratio is appropriately selected depending on the composition of the synthetic resin and the performance required for the product. Usually, a range of 1 to 80% by volume, preferably 2 to 50% by volume is appropriate.

[0038]

Next, an embodiment of the present invention will be described.
This will be described with reference to the drawings.

First, as shown in FIG. 1, the mold for producing a tubular body used in the method of the present invention comprises an inner mold (1) and an outer mold (2), and an inner mold (1) and an outer mold. An annular flow path (3) may be formed between the outer mold (2) and the outlet end face of the inner mold (1) and the outlet end face of the outer mold (2) may coincide on the same vertical plane.

As shown in FIG. 2, the outlet end face of the inner mold (1) may protrude from the outlet end face of the outer mold (2). As shown in FIG. The end face may enter into the inside from the outlet end face of the outer mold (2).

The inner mold (1) and the outer mold (2) may be composed of not only a single member but also a plurality of members, and the members include heating means and cooling means. May be.

In the mold for manufacturing a tubular body used in the method of the present invention, at least a part of at least one of the inner mold and the outer mold (2) is provided with a rotating shaft extending in the same direction as the resin extrusion direction. And a drive rotatable part which is rotated by the drive means is provided, and either one or both drive rotatable parts are rotated by the drive means. The directions may be the same or opposite.

4 to 7 Here, the arrows in FIGS. 4 to 7 indicate the rotation direction of the drive rotary mold part in the inner mold (1) or the outer mold (2). As shown in FIG. 5, only the inner mold (1) may be rotatable, or as shown in FIG. 5, only the outer mold (2) may be rotatable, and the inner mold (1) and the outer mold (2) may be rotated. When both are rotatably supported, the rotation directions of both the inner mold (1) and the outer mold (2) may be the same direction as shown in FIG. 6, or as shown in FIG. Alternatively, the direction may be different.

In the present invention, the number of revolutions of at least one of the inner and outer molds (1) and (2) is not particularly limited. In consideration of the orientation, the rotation speed of the drive rotary mold portion is 1 to
It is 1000 rpm, preferably 1 to 100 rpm.

Here, the rotation speed of the drive rotary type part is 1 rpm.
If less than the above, the orientation effect of the reinforcing material cannot be sufficiently obtained, and conversely,
If the number of rotations exceeds 1000 rpm, shear heat generation becomes remarkable and molding becomes difficult.

Regarding the structure of the non-driven rotary mold part In the present invention, as shown in FIG. 8, the mold (44) for producing a tubular body according to the present invention comprises a part of the inner mold (1), (1
If the other part of the inner mold (1) is a non-driving rotary part (12) that does not rotate and can rotate slightly, the driving die (11) and the non-driving rotary part Bearing between (12)
(B) may be interposed.

As shown in FIG. 9, a case where a part of the outer mold (2) is a driving rotary part (21) and another part of the outer mold (2) is a non-driving rotary part (22). In this case, a bearing (B) may be interposed between the drive rotary mold (21) and the non-drive rotary mold (22).

As shown in FIG. 10, a part of the inner mold (1) is a driving rotary part (11), and the other part of the inner mold (1) is a non-driving rotary part (12). A part of the outer mold (2) is used as a drive rotary part (21), and the other part of the outer mold (2) is used as a non-drive rotary part (2).
In the case of (2), the bearings (11) and (21) and the non-drive rotating parts (12) and (22) of the inner mold (1) and outer mold (2) B) (B) may be interposed.

Further, as shown in FIG. 11, a case where a part of the inner die (1) is a drive rotary type part (11) and another part of the inner die (1) is a non-drive rotary type part (12). A shaft (11a) protruding from the end of the drive rotary mold (11), a cylindrical portion (12a) at the end of the non-drive rotary mold (12), and a drive rotary mold (11). ) Is inserted into the cylindrical portion (12a) of the non-drive rotary type portion (12), and the shaft portion (11a) is inserted.
The bearing (B) may be interposed between the cylinder and the cylindrical portion (12a).

As shown in FIG. 12, a case where a part of the outer mold (2) is a drive rotary type part (21) and another part of the outer mold (2) is a non-drive rotary type part (22). A shaft portion (21a) protruding from the end of the drive rotary mold portion (21), and a cylindrical portion (22a) at the end of the non-drive rotary mold portion (22). The shaft part (21a) of the non-drive rotary type part (22) is inserted into the cylindrical part (22a) of the non-drive rotary type part (22), and the shaft part (21a) of the drive rotary type part (21) and the non-drive rotary type part (22). Tube part (22a)
The bearing (B) may be interposed between the bearing and the bearing.

As shown in FIG. 13, a part of each of the inner mold (1) and the outer mold (2) is a drive rotary mold part (11) (21), and the inner mold (1) and the outer mold (2) The other part of the non-drive rotary part (12) (2
In the case of (2), the shaft part is attached to the end of the drive rotary type part (11) (21).
(11a) (21a) protruding, the cylindrical portion (11a) (21a) is provided at the end of the non-drive rotary type part (11) (22), the shaft part of the drive rotary type part (11) (21) (1
The bearings (B) and (B) may be interposed between the cylindrical portions (12a) and (22a) of the non-drive rotary mold portions (12) and (22).

As shown in FIG. 14, a part of the inner die (1) is a drive rotary die (11), and the other part of the inner die (1) is a non-drive rotary die (12). In this case, a shaft (11a) is protruded from the end of the drive rotary mold (11), while a cylinder (12a) is provided at the end of the non-drive rotary mold (12). 11a) into the cylindrical portion (12a), and between the shaft portion (11a) and the cylindrical portion (12a).
A sliding member (T) made of phosphor bronze or Teflon may be interposed.

The sliding member (T) is preferably devised to reduce the contact resistance.

In the present invention, as shown in FIG. 15, the length in the extrusion direction of the resin contact portion of the drive rotary mold part (11) of the inner mold (1) is Lr, and the inner mold (1) and the outer mold ( 2) Annular flow path between
Assuming that the size of the gap in (3) is Dr, the value of Lr / Dr is preferably at least 1 and preferably at least 5 and at most 100 for the circumferential orientation of the reinforcing material contained in the synthetic resin. More preferably, Here, if the value of Lr / Dr is less than 1, it is difficult to orient the reinforcing material approximately in the rotational direction.

The rotating shaft (13) of the drive rotary mold (11) of the inner mold (1) is held by a holder (14) and a bearing (15).
The tip of the rotating shaft (13) is connected to a motor (45).

In the present invention, as shown in FIG. 16, the length in the extrusion direction of the resin contact portion of the non-drive rotary mold portion (12) of the inner mold (1) is Ls, and the inner mold (1) and the outer mold ( 2) Annular flow path between
Assuming that the size of the gap in (3) is Ds, the value of Ls / Ds is preferably in the range of 1 to 100.

Here, when the value of Ls / Ds is less than 1, the tubular body extruded from the mold outlet may be rotated. It is not preferable that the reinforcing material to be mixed is oriented in the circumferential direction of the tubular body, because it is likely to be reoriented in the longitudinal direction of the tubular body due to the shearing force in the extrusion direction.

In the present invention, as shown in FIG. 17, in order to rapidly solidify the synthetic resin in a molten state and to obtain a desired degree of orientation of the reinforcing material, the vicinity of the outlet of the annular flow path (3) is required. It is preferable that at least a part of the inner mold (1) and the outer mold (2) is provided with a cooling means (4) such as winding a copper pipe for cooling water circulation.

Although the cooling temperature varies depending on the synthetic resin used, in the case of a crystalline resin such as a polyethylene resin or a polypropylene resin, it is preferable that the temperature be around the melting point, and that of an amorphous resin such as a vinyl chloride resin. In this case, it is preferable that the temperature is around the softening point. If the cooling temperature is too low, the molding pressure becomes abnormal and molding becomes difficult, which is not preferable.

In the present invention, as the rotating means of the inner or outer driving rotary mold part, as shown in FIG. 18, the inner or outer driving rotary mold part of the mold (44) is rotated from the rotating shaft ( S
a), and attach a sprocket wheel (W1) to the rotating shaft (Sa) .This sprocket wheel (W1) and motor (4
A power transmission mechanism (C) such as a belt or a chain is stretched between the sprocket wheel (W2) attached to the rotation shaft of (5) and the rotation of the motor (45) is rotated by the driving rotary part of the mold (44). May be transmitted.

As shown in FIG. 19, the drive rotary mold part of the mold (44) and the rotating shaft of the motor (45) are directly connected by a power transmission mechanism (U) having a universal joint, and the motor (45) is connected. ) May be transmitted to the drive rotary mold part of the mold (44).

Further, as shown in FIG. 20, the rotation axis (Sa) of the drive rotary mold part of the mold (44) and the rotation axis (Sm) of the motor (45) are reduced by a worm speed reducer or a cyclone speed reducer. It may be directly connected by the machine (48) and transmitted.

Alternatively, as shown in FIG.
4) The rotation axis (Sa) of the rotary part and the rotation axis of the motor (45)
(Sm) may be connected via a pair of bevel gears (G1) and (G2) to transmit the rotation of the motor (45) to the drive rotary mold part of the mold (44).

Further, as shown in FIG. 22, a reduction gear (48) may be directly interposed between the drive rotary mold part of the mold (44) and the motor (45) to transmit the driving force. good.

The above-mentioned various rotating means may be used alone or in combination.

Further, in order to prevent the synthetic resin from drifting in the annular flow path (3), it is desirable to provide an anti-shake means on the rotating shaft of the drive rotary mold part.

Next, a method for producing the tubular body of the present invention will be described.

The synthetic resin and the reinforcing material are extruded at, for example, an extruder (41) shown in FIG. 23 at a temperature equal to or higher than the melting point or softening temperature of the resin. It passes through an annular flow path (3) composed of 1) and an outer mold (2). Inner mold
(1) or a part of the outer mold (2) has a drive rotary mold part that rotates in a vertical plane perpendicular to the extrusion direction, and the mixture is moved while passing through the annular flow path (3). Is affected by the shearing force due to the rotation of the drive rotary mold part, and the orientation of the reinforcing material in the circumferential direction of the tubular body is promoted.

The mixture that has passed through the annular flow path passes through a non-drive rotary type section that is not driven and rotated and extends downstream of the drive rotary type section, is rectified there, and is cooled near the outlet of the annular flow path (3). Then, while being maintained in a desired orientation state, it is extruded from an outlet which is a terminal flow path of the non-driven rotary type portion.

As the extrusion method in the present invention, any conventionally known method may be employed. For example, a single screw extruder,
A twin screw extruder is used.

In FIG. 23, the tubular body (36) extruded from the extruder (41) and formed in the mold (44) is cooled.
It is necessary to cool to a temperature at which the shape of the tubular body and the dimensions of the inner diameter and the outer diameter do not change plastically at least in the taking-off step, and it is desirable to cool to the ambient temperature (outside air temperature).

As means (46) for cooling the tubular molded body,
Having a shaping mold (49), and a method of passing a tubular molded body through a refrigerant such as a water tank, a method of applying cool air with a blower, etc.,
A method of passing through a cooling die through which a refrigerant flows can be used, and the method is appropriately selected according to the dimensions of the tubular molded body and the molding line.

Means (47) for withdrawing the cooled tubular compact
For example, a belt type take-up machine, a caterpillar type take-up machine, a roll type take-up machine, a rotary take-up machine and the like can be used as appropriate.

Referring to FIGS. 8 to 17, the tubular mold (44) of the present invention has an annular flow path (3) formed between the inner mold (1) and the outer mold (2). A part of at least one of the inner mold (1) and the outer mold (2) is provided with a rotatably supported drive rotary mold part, and the drive rotary mold part is rotated by drive means. A non-drive rotary type part that is not driven and rotated downstream of the drive rotary type part is extended,
An outlet of the flow path is provided in the non-driven rotary type part, and cooling means (4) is provided in the non-driven rotary type part of at least one of the inner die and the outer die near the outlet of the annular flow path. I have.

According to the method for producing a tubular body of the present invention, a mixture containing a reinforcing material and a synthetic resin is mixed with a mold (44) connected to an extruder (41) as shown in FIG. Annular channel
(3), and the mixture is formed into a tubular shape so that the mixture is subjected to a shearing force in a substantially rotational direction from the drive rotary mold part (11) while passing through the annular flow path (3). After forming a tubular molded body oriented in the circumferential direction, and then passing this tubular molded body through a flow path portion corresponding to the non-driven rotary mold part (12) in the annular flow path (3), it is cooled. From the exit of the annular flow path.

Here, the drive rotary type portion (11) and the non-drive rotary type portion (12) inside the annular flow path (3) are connected via a connection shaft (60). Is equipped with a thrust bearing (61) and a sliding member (62) is interposed between them, and the non-drive rotary type part (12) can rotate slightly freely, not by the driving means It has been done.

According to the method of the present invention, as shown in FIG. 25, it is possible to form a product of a tubular body (36) made of a resin (32) with the reinforcing material (31) oriented in the circumferential direction. is there.

In the present invention, as shown in FIG. 26, the non-drive rotary type portion (12) of the inner die (1) is provided with a convex portion (9) projecting toward the annular flow path (3). In the case where a channel portion (3a) narrower than the other portion is formed in the annular channel (3), if the size of the gap of the annular channel (3) is Ds, the inside of the annular channel (3) is The height (H) of the protruding projection (9) is at least 1/10 Ds and less than Ds, preferably at least 2/10 Ds and 8 / Ds.
The range is less than 10 Ds.

Here, the height (H) of the projection (9) is 1 / 10D
In the case of less than s, the effect of providing the convex portion (9), that is, the rotation of the extruded tubular molded body is suppressed, and the reinforcing material is substantially uniformly distributed in the circumferential direction of the tubular body in the inner and outer layers of the molded tubular body. It is difficult to obtain the effect of orientation, and the height of the protrusion (9)
(H) does not exceed Ds, of course.

As shown in the figure, the protrusion (9) provided on the non-driven rotary mold part (12) of the inner mold (1) has a width (in the extrusion direction) protruding into the annular flow path (3). a) is 1/10 Ds or more and 10D, where Ds is the size of the gap of the annular flow path (3).
It is preferably within the range of s or less.

Here, the width (a) of the projection (9) is 1/10 Ds
When the width is less than 10 Ds, it is difficult to obtain the effect of the convex portion (9), and when the width (length in the extrusion direction) (a) of the convex portion (9) is larger than 10 Ds, shearing in the extrusion direction occurs. Since the force is continued to be applied, the reinforcing material that has been roughly oriented in the rotational direction is again oriented in the extrusion direction, and the reinforcing material is not reinforced in the circumferential direction of the tubular body.

Incidentally, on both front and rear sides of the convex portion (9), an inversely tapered inlet-side gradient portion (c1) and a tapered outlet-side gradient portion are provided.
Although (c2) is provided, the width (a) of the convex portion (9) does not include these gradient portions (c1) and (c2).

The slope (c1) on the entrance side of the projection (9) is 15
The angle is not less than 90 degrees and less than 90 degrees, and the outlet-side gradient portion (c2) of the convex portion (9) is not particularly limited.

Here, if the inlet slope (c1) is less than 15 degrees, the gradient is too gentle to exert a braking effect, and the range in which a shear force is applied in the extrusion direction is inevitably increased. It will be easier.

It is preferable that the protruding portion (9) of the non-drive rotary mold portion (12) be installed immediately after the drive rotary mold portion (11) (downstream of molding) as much as possible.

In the present invention, the distinction between the drive rotary type part (11) and the non-drive rotary type part (12) is made by the part in contact with the molten resin. For example, as shown in FIG. The shaft (11a) protruding from the part (11) and the non-drive rotary type part (1
The structural overlap with the tubular portion (12a) provided in 2) is negligible.

[0087]

Next, embodiments of the present invention will be described with reference to the drawings.

Example 1 Using the manufacturing equipment shown in FIG.
A 3.0 mm thick tubular body (37) was produced.

The synthetic resin has a density of 0.935 g /
Medium density polyethylene having a cm ³ and a melt index of 0.20 g / 10 minutes was used.

As the reinforcing material mixed with the synthetic resin, 4% by volume of a glass fiber chopped strand having a diameter of 15 μm and a length of 5 mm was dry-mixed with a mixer.

The number of rotations of the flow path made to rotate coaxially with the extrusion direction is 50 rpm, and the size of the annular gap Dr of the flow path made to rotate coaxially with the extrusion direction is set to 3.0 mm. , The length in the extrusion direction of the flow path that does not rotate is L
s was set to 30 mm, the size Ds of the annular problem of the non-driving flow path was set to 3.0 mm, and the value of Ls / Ds was set to 10.

As the extruder (41), a single screw extruder was used. The melting temperature of the synthetic resin was 200 ° C., and the temperature of the outer mold was 200 ° C.
The inner mold was not cooled or heated. The extrusion speed was 0.50 m / min.

Next to the mold (44), a cooling and shaping step is provided in a vacuum spray water tank (46) incorporating a shaping mold (49), and a tubular body (47) is provided by a belt type take-off machine (47). 37).

Example 2 In Example 1, the inner mold was cooled by circulating silicone oil, and the temperature was set to 130 ° C., which is around the melting point of polyethylene used.

Example 3 In Example 1, as a reinforcing material mixed with a synthetic resin,
A 10% by volume wholly aromatic liquid crystal polyester having a liquid crystal transition temperature of 280 ° C. by DSC was dry-mixed with a mixer. The temperature of the molten resin in the drive rotary section flow path is 290 ° C., the temperature of the outer mold is 290 ° C., the temperature of the molten resin near the end of the non-drive rotary section flow path is 200 ° C., and the temperature of the outer mold is 200 ° C. Cooling.

Comparative Example 1 In Example 1, the end of the flow path that was made to rotate coaxially with the extrusion direction was the mold exit, and no flow path that was not driven and rotated was not provided.

Evaluation: Comparison of Rotational Speed at the Time of Manufacturing Tubular Body With respect to the above Examples 1 to 3 and Comparative Example 1, the rotational speed at the time of manufacturing the tubular body was measured by the point immediately after the tubular body manufacturing mold (44). Measured in (50). Table 1 shows the results of comparing the rotational speeds at the time of manufacturing the tubular body.

[0098]

[Table 1] As is evident from Table 1, in Examples 1 to 3, the rotational speed at the time of manufacture was much slower than that in Comparative Example 1, and therefore, no tubular take-up machine or a tubular take-up using a low-rotation take-up machine was used. Obviously the body can be made.

Example 4 In manufacturing a tubular body according to the present invention, first, a glass fiber chopped strand having a diameter of 10 μm and a length of 3 mm was used as a reinforcing material, and a density of 0.935 was used as a thermoplastic resin.
g / cm ³ , polyethylene having a melt index (M1) of 2.0 g / 10 min.

Then, the mixing amount of the glass fibers was adjusted to 8% by volume, and the mixture was preliminarily mixed with a tumbler mixer.

Then, the obtained mixture was heated at a resin temperature of 190 ° C. using a single screw extruder (41) having a screw diameter of 50 mm.
And was extruded into a mold (44).

The mixture was placed in a mold (44) shown in FIG.
While passing through the annular flow path (3) composed of the inner mold (1) and the outer mold (2), at the same time, the drive rotary mold part (11) of the inner mold (1) was installed outside the mold. Reducer by motor (45) shown in FIG.
Rotated through (48).

Here, the mixture comprising the reinforcing material (31) and the thermoplastic resin (32) is supplied from the manifold (42) shown in FIG. 27 to the annular flow between the inner mold (1) and the outer mold (2). The annular flow path (3) is annularly developed at the start end of the path (3) and faces the drive rotary mold (11).
A), and is further pushed out into the annular flow path (3B) which faces the non-drive rotary type part (12) which does not rotate but can rotate freely.

At this time, the outer diameter of the inner mold (1) was 55 mm,
The inner diameter of (2) was set to 66 mm.

Further, for the drive rotary type part (11), Lr /
Dr = 13.6 (Lr = 75, Dr = 5.5) (FIG. 15)
Reference) and the number of rotations was 10 rpm.

For the non-drive rotary type part (12), Ls / D
s = 7.3 (Lr = 40, Dr = 5.5) (see FIG. 15).

The temperature of the outer mold (2) of the mold (44) was set to 200 ° C.
The inner mold (1) of the mold (44) was performed without cooling and without heating.

Thus, the reinforced glass fiber mixed in the polyethylene resin is oriented in the circumferential direction of the tubular body by the rotation of the drive rotary mold part (11), and further, the annular flow path (3) of the mold (44).
From the outlet on the side of the non-driven rotary mold part (12), a tubular body having a reinforcing material oriented in the circumferential direction and whose rotation was suppressed could be formed.

Further, the tubular body (36) pushed out from the outlet of the mold (44) is cooled in a cooling water tank (46) shown in FIG.
With a take-up machine (47), the outer diameter is about 60 mm and the wall thickness is about 5 m
m was taken out and further cut to a required length by a cutting machine (49) to produce a tubular product (37).

Embodiment 5 The same procedure as in Embodiment 4 is carried out, but as shown in FIG. 28, the inner mold (1) protrudes toward the annular flow path (3) from the non-driving rotary mold part (12). A convex portion (9) was provided, and a flow path portion (3a) narrower than other portions was formed in the annular flow path (3).

Here, the size of the gap (Ds) in the annular flow path (3)
Was set to 5 mm. The convex portion (9) is a band-shaped raised body, and the convex portion
The height (H) of (9) is 2.5 mm, the length (a) of the protrusion (9) in the extrusion direction is 10 mm, and the slope (c) on the inlet side of the protrusion (9) is
1) is 2.5 / 5.0 = 0.5 (→ 26.6 degrees), and the exit side gradient (c2) is 2.5 / 5.0 = 0.5 (→ 26.6 degrees).
And

Further, a copper cooling pipe (4) having a length of 40 mm and a diameter of 8 mm is wound around the portion of the outer mold (2) near the outlet of the annular flow path to form a cylindrical cooling zone. The temperature of the cooling zone was set to 120 ° C., which is around the melting point of the resin used in Example 1.

At this time, the zone being cooled is the inner mold
The non-driving rotary part (12), which is a part of (1), and the flow path corresponding to the part of the outer die (2) near the annular flow path outlet.

Except for the above points, the same procedure as in Example 1 was carried out, and the reinforced glass fibers mixed in the polyethylene resin were oriented in the circumferential direction of the tubular body, and the rotation was sufficiently suppressed. A tubular body could be formed.

Embodiment 6 The same procedure as in Embodiment 5 is carried out, except that, as shown in FIG. 26, the non-driven rotary mold part (12) of the inner mold (1) projects toward the annular flow path (3). A convex portion (9) was provided, and a flow path portion (3a) narrower than other portions was formed in the annular flow path (3). But the outer type
No cooling means (4) was provided at the outlet of the annular flow path in (2).

[0116] Except for the above points, the same procedure as in Example 2 was carried out, wherein the reinforced glass fibers mixed in the polyethylene resin were oriented in the circumferential direction of the tubular body, and the rotation of the tubular body was suppressed. Could be molded.

COMPARATIVE EXAMPLE 2 For comparison, the drive rotary type part was not driven (rotation speed = 0 rpm).
A tubular body was produced in the same manner as in Example 4 except for the point of m).

Comparative Example 3 For the purpose of comparison, the operation was carried out except that the non-drive rotary type portion was not extended and the end (11a) of the drive rotary type portion was the outlet of the annular flow path (3). In the same manner as in Example 4, a tubular body was produced.

At this time, the inner mold (1) (= drive rotary mold part)
And the inner diameter of the outer mold (2) is 66 mm, and Lr / Dr = 13.6 (Lr = 7
5, Dr = 5.5) and the number of rotations was 10 rpm,
This is the same as the case of the fourth embodiment.

Evaluation of Tubular Molded Article Next, in order to evaluate the performance of the tubular molded article obtained in the above Examples and Comparative Examples, the following test pieces were cut out from the obtained tubular molded article. Then, two types of tensile tests in the axial direction and in the circumferential direction were performed on the test piece of each tubular body molded article in accordance with ASTM D638, and the tensile strength in the axial direction and in the circumferential direction were measured. The results are summarized in Table 2 below.

From the results in Table 2, the difference in the orientation of the glass fibers was compared and examined from the difference in the strength of the tubular body in the axial and circumferential directions.

In the case of an axial tensile test: A substantially rod-shaped test piece having a thickness of 5 mm, a width of 10 mm, and a length of 100 mm was cut out from a molded article of the tubular body along the longitudinal direction of the tubular body, and both ends of the specimen were each cut. A tensile test was performed by holding the chuck with a normal chuck.

In the case of a tensile test in the circumferential direction: A ring-shaped test piece having a width of 30 mm was cut out from a molded article of a tubular body, and the test piece was pulled in a radial direction in a state where the test piece was gripped by a semicircular jig to conduct a tensile test. Was.

[0124]

[Table 2] As is clear from the results in Table 2 above, Example 4 of the present invention
According to Nos. 6 to 6, the tensile strength in the circumferential direction of the obtained tubular molded body (36) is very large, has sufficient strength and rigidity, and is mixed in the thermoplastic resin (32). Reinforcement
(31) were all efficiently oriented in the circumferential direction.

On the other hand, in the tubular molded body of Comparative Example 2,
The tensile strength in the circumferential direction was small, and the strength and rigidity were insufficient. In Comparative Example 3, when the tubular body was extruded while rotating without preparing a special take-off device, it was difficult to take out.

[0126]

According to the present invention, as described above, according to the method for manufacturing a tubular body and the mold for manufacturing a tubular body according to the present invention, the rotation of the tubular body extruded from the mold can be suppressed,
In the inner and outer layers of the formed tubular body, a reinforcing material can be formed into a tubular body oriented substantially uniformly in the circumferential direction of the tubular body, and the strength and rigidity in the circumferential direction reinforced efficiently in the circumferential direction by the reinforcing material. An excellent tubular body can be continuously formed.

When considered as a molding line for a tubular body, the tubular body extruded from the mold is not sent to the next step while rotating as in the conventional case. Machines, take-off machines, cutting machines, and the like do not require complicated and expensive equipment, and the equipment cost is very low.

Further, by providing a cooling means in the non-drive rotary mold portion of at least one of the inner mold and the outer mold near the outlet of the annular flow path of the mold, the cooling rate of the molten resin can be selected. Therefore, a desired orientation state can be more easily obtained, and it is possible to prevent a situation where the non-driven rotary mold portion is again oriented in the extrusion direction.

Further, a convex portion protruding into the annular flow path is provided in the non-drive rotary mold portion of the mold to form a flow path portion narrower than the other portions, whereby a narrow flow due to the convex portion is formed. When the molten resin passes through the road portion, the rotation of the tubular body is further suppressed by the so-called braking effect, and the tubular body is molded in a state where it does not rotate further, and is efficiently and sufficiently reinforced in the circumferential direction by the reinforcing material. This produces an effect that a tubular body having excellent circumferential strength and rigidity can be manufactured.

The molded article of the tubular body produced according to the present invention can be suitably used for applications requiring strength and rigidity in the circumferential direction among various pipes and poles.

[Brief description of the drawings]

FIG. 1 is an enlarged vertical sectional view of a main part of a mold to which the present invention is applied, showing a case where an outlet end face of an inner mold and an outlet end face of an outer mold coincide on the same vertical plane.

FIG. 2 is an enlarged longitudinal sectional view of a main part of a mold to which the present invention is applied, and shows a case where an outlet end face of an inner mold projects outside an outlet end face of an outer mold.

FIG. 3 is an enlarged vertical sectional view of a main part of a mold to which the present invention is applied, and shows a case where an outlet end face of an inner mold enters inside an outlet end face of an outer mold.

FIG. 4 is an enlarged cross-sectional view of a main part of a mold to which the present invention is applied, showing a case where an inner mold is driven and rotated.

FIG. 5 is an enlarged cross-sectional view of a main part of a mold to which the present invention is applied, showing a case where an outer mold is driven and rotated.

FIG. 6 is an enlarged cross-sectional view of a main part of a mold to which the present invention is applied, showing a case where both the inner and outer dies are driven and rotated in the same direction.

FIG. 7 is an enlarged cross-sectional view of a main part of a mold to which the present invention is applied, showing a case where inner and outer dies are driven and rotated in different directions.

FIG. 8 is an enlarged sectional view of a main part showing a first example of a mold for producing a tubular body used in the method of the present invention.

FIG. 9 is an enlarged sectional view of a main part showing a second example of a mold for producing a tubular body used in the method of the present invention.

FIG. 10 is an enlarged sectional view of a main part showing a third example of a mold for producing a tubular body used in the method of the present invention.

FIG. 11 is an enlarged sectional view of an essential part showing a fourth example of a mold for producing a tubular body used in the method of the present invention.

FIG. 12 is an enlarged sectional view of a main part showing a fifth example of a mold for producing a tubular body used in the method of the present invention.

FIG. 13 is an enlarged sectional view of a main part showing a sixth example of a mold for producing a tubular body used in the method of the present invention.

FIG. 14 is an enlarged sectional view showing a seventh example of a mold for producing a tubular body used in the method of the present invention.

FIG. 15 is an enlarged sectional view of a main part showing a specific example of the mold for manufacturing a tubular body of FIG. 11;

FIG. 16 is an enlarged sectional view of a main part showing a specific example of the mold for manufacturing a tubular body of FIG. 8;

17 shows a specific example of the mold for manufacturing a tubular body of FIG. 8, and is an enlarged sectional view of a main part when a cooling means is provided on the outer periphery of the outer mold.

FIG. 18 is a schematic side view showing a specific example in which a rotating means is connected to a mold for producing a tubular body used in the method of the present invention.

FIG. 19 is a schematic side view showing another specific example in which a rotating means is connected to a mold for producing a tubular body used in the method of the present invention.

FIG. 20 is a schematic side view showing still another specific example in which a rotating means is connected to a mold for producing a tubular body used in the method of the present invention.

FIG. 21 is a schematic side view showing another embodiment in which a rotating means is connected to a mold for producing a tubular body used in the method of the present invention.

FIG. 22 is a schematic side view showing another specific example in which rotating means is connected to a mold for producing a tubular body used in the method of the present invention.

FIG. 23 is a schematic side view showing an entire apparatus for performing the method for manufacturing a tubular body of the present invention.

24 is an enlarged cross-sectional view of a mold part for manufacturing a tubular body in FIG. 23.

FIG. 25 is a perspective view of a tubular body manufactured by the method of the present invention.

26 shows a specific example of the metal mold for manufacturing a tubular body of FIG. 11, and is an enlarged cross-sectional view of a main part when an annular convex portion is provided on a non-driving rotary mold part of an inner die.

FIG. 27 is an enlarged cross-sectional view of the tubular body manufacturing mold portion of FIG. 23, showing a case where an annular convex portion is provided on a non-drive rotary mold portion of the inner mold.

FIG. 28 is an enlarged sectional view of a main part when a cooling means is provided on the outer periphery of the outer mold of the metal mold for manufacturing a tubular body of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner die 2 Outer die 3 Annular flow path 4 Cooling means 9 Convex part 11 Drive rotation type part 12 Non-drive rotation type part 21 Drive rotation type part 22 Non-drive rotation type part 31 Reinforcement material (reinforced fiber) 32 Synthetic resin (Heat (Plastic resin) 36 tubular molded body 37 tubular body product 41 extruder 44 mold 45 motor (rotation drive means)

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Koichi Kariya 2-2 Sekisui Kagaku Kogyo Co., Ltd.

Claims (7)

[Claims] 1. A mixture containing a reinforcing material and a synthetic resin is introduced from an extruder into an annular flow path of a mold connected thereto,
A part of at least one of the inner mold and the outer mold that forms the annular flow path is provided with a drive rotary mold part that rotates about a rotary shaft extending in the same direction as the resin extrusion direction and that is rotated by a drive unit. On the downstream side in the resin extruding direction of the drive rotary mold portion, a non-drive rotary mold portion that is not rotatable by the drive means but can freely rotate is extended, and the outlet of the annular flow path is provided on the non-drive rotary mold portion side. Provided, the mixture is formed into a tubular shape so as to pass through the annular flow path and receive a shearing force in the direction of rotation from the driving rotary mold part during the passage,
After forming a tubular molded body in which the reinforcing material is oriented in the circumferential direction, the tubular molded body is passed through the flow path portion corresponding to the non-driven rotary mold portion in the annular flow path, and then extruded from the annular flow path outlet. A method for producing a tubular body, characterized in that: 2. The method for producing a tubular body according to claim 1, wherein a fibrous reinforcing material is used as the reinforcing material, and a thermoplastic resin is used as the synthetic resin. 3. The method according to claim 1, wherein at least a part of the flow path portion corresponding to the non-drive rotary type portion that is not rotated by the drive means is cooled more than the flow path portion corresponding to the drive rotary type portion rotated by the drive means. The method for producing a tubular body according to claim 1, wherein the molded body is cooled near an outlet in the annular flow path, and then extruded from the outlet. 4. A projection protruding toward an annular flow path is provided on at least a part of a non-driving rotary type part provided on at least one of an inner mold and an outer mold, and is provided in the annular flow path. A channel portion narrower than other portions is formed, and the mixture is
It is formed into a tubular shape so that it passes through the annular flow path and receives a shearing force in the direction of rotation from the driving rotary mold part during the passage, thereby forming a tubular molded body in which the reinforcing material is oriented in the circumferential direction. 2. The method for manufacturing a tubular body according to claim 1, wherein the tubular body is passed through a narrow channel portion in the annular channel and then extruded from an annular channel outlet. 5. An annular flow path comprising an inner mold and an outer mold, wherein at least a part of at least one of the inner mold and the outer mold has a center on a rotation axis extending in the same direction as the resin extrusion direction. And a driving rotary type part that is rotated by the driving means is provided, and a non-driving rotary type part that is not rotated by the driving means but is slightly free rotatable is extended downstream of the driving rotary type part in the resin extrusion direction, A mold for producing a tubular body, characterized in that an outlet of an annular flow path is provided on the non-drive rotary mold part side. 6. The production of a tubular body according to claim 5, wherein a cooling means is provided in at least one of the inner mold and the outer mold in a flow path portion corresponding to the non-driven rotary mold part of the annular flow path. Mold. 7. A non-driving rotary part having at least a part thereof provided with a convex part protruding toward the annular flow path, and a flow path part narrower than other parts is formed in the annular flow path. The mold for manufacturing a tubular body according to claim 5.