JPH09309139A - Manufacture of tubular form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing continuously a tubular form which is reinforced with a fibrous liquid crystal resin oriented efficiently in the peripheral direction of the tubular form and also is of the exceedingly high strength and rigidity in the peripheral direction. SOLUTION: A mixture of liquid crystal resin 41 and thermoplastic resin 42 with a lower melting point or melting temperature than the transition point is injected into a first cylindrical flow path 31 of a cross heat die. In addition, a rotary die 22 is arranged at least, on one of the inner or the outer side of the first flow path 31, and the mixture is caused to flow through the first flow path 31 at a temperature higher than the transition point of the crystal liquid resin 41, and further, is shaped into a tubular shape so that the mixture receives a torsional shear while passing through the first flow path 31. Thus a tubular molding 43 consisting of the liquid crystal resin 41 oriented in the peripheral direction is formed. Next, the tubular molding 43 is injected into a second cylindrical flow path 32 with the inner and the outer peripheral face divided by a fixed wall part. Further, the tubular molding 43 is caused to pass through the second cylindrical flow path 32 at a temperature lower than the transition point of the liquid crystal resin 41 and the melting point or the melting temperature of the thermoplastic resin 42 to obtain a molded fiber-reinforced tubular form 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tubular body used for pipes, poles, etc., which has excellent strength and rigidity in the circumferential direction.

[0002]

2. Description of the Related Art As this type of tubular body, a tubular body made of metal and a tubular body made of fiber reinforced resin (FRP) mixed with glass fiber or carbon fiber have already been proposed.

Further, as a synthetic resin molded article having high strength and high rigidity in which glass fibers and carbon fibers are not mixed, a fibrous liquid crystal resin is compounded in a matrix resin in JP-A-62-116666 to form a film. Extrusion techniques are disclosed.

Further, JP-A-5-193010 discloses a method for producing a molded product by a filament winding method using a strand of a liquid crystal resin composite.

On the other hand, it is well known that the liquid crystal resin is in a liquid crystal state in the temperature range above the transition point and is easily oriented by external stress such as shearing force.

[0006]

However, when the liquid crystal resin is applied to the production of the tubular body, in the conventional extrusion molding method, according to the technique described in the above-mentioned publication, the matrix in the matrix is formed in the molding step. Although the liquid crystal resin becomes fibrous and becomes a reinforcing material, the orientation of the liquid crystal resin is affected by the flow in the mold, and the liquid crystal resin is oriented in the longitudinal direction of the tubular body, so that the strength of the final product is sufficient. There is a problem that rigidity cannot be expressed.

Further, according to the technique described in the above publication, the strength and rigidity in the circumferential direction of the final product are improved to some extent by winding the strand made of the liquid crystal resin and the thermoplastic resin in the circumferential direction of the tubular core material. However, since the strength and rigidity of the tubular body against internal and external pressures depend on the bonding state of the strands in the coating layer and it is difficult to ensure sufficient bonding between the strands, the strength and rigidity of the tubular body are There was a problem that it was not enough.

An object of the present invention is to solve the above problems of the prior art and to provide a method for continuously manufacturing a tubular body which is efficiently reinforced with a liquid crystal resin and is excellent in circumferential strength and rigidity. There is.

[0009]

In order to achieve the above-mentioned object, the present invention provides a mixture of a liquid crystal resin and a thermoplastic resin having a melting point or a melting temperature lower than the transition point of the liquid crystal resin, in an extruder. Further, it is introduced into the cylindrical first flow path of the crosshead die connected thereto, and a rotary shaft extending in the same direction as the resin extrusion direction is centered on at least one of the inner and outer sides of the cylindrical first flow path. A rotary mold that rotates as is arranged to allow the mixture to pass through the cylindrical first flow path at a temperature equal to or higher than the transition point of the liquid crystal resin and to be tubularly shaped so as to be subjected to torsional shear during the passage. To form a tubular molded body in which the liquid crystal resin is oriented in the circumferential direction, and the tubular molded body is connected to the cylindrical first flow path and has an inner peripheral surface and an outer peripheral surface defined by a fixed wall portion. Introduced into the second channel, the second channel is a liquid crystal By passing a melting point or a temperature above the melting temperature of below the transition point of the fat and the thermoplastic resin is characterized by molding the fiber-reinforced tubular body where the liquid crystal resin is oriented in the circumferential direction.

In the present invention, as the thermoplastic resin used as a matrix by being mixed (blended) with the liquid crystal resin, ABS resin, ethylene-vinyl acetate copolymer, fluororesin, acetal resin, amide resin, imide resin, Amid-imide resin, acrylic resin, vinyl chloride resin, olefin resin, polyester, polycarbonate, polyacrylate, polyphenylene oxide, polystyrene, thermoplastic polyurethane, etc., or a modifier or blend material (alloy material) of these resins can be melt-molded Resin.

If necessary, a compatibilizer may be added in order to improve the compatibility with the liquid crystal resin. Here, examples of the compatibilizer include a graft polymer of a liquid crystal resin component or a graft polymer having a polar component such as a carboxylic acid group or an amino group.

On the other hand, the liquid crystal resin is not particularly limited as long as it has a liquid crystal transition temperature higher than the melting point or melting temperature of the above-mentioned thermoplastic matrix resin, but thermoplastic liquid crystal polyester and thermoplastic polyester amide are used. Preferably, specifically, Vectra, Econol,
Aromatic polyester-based liquid crystal polymers that are commercially available under the trade names of Zaider, Rodrun, and the like are included.

In the composition in which the thermoplastic resin as the matrix and the liquid crystal resin are blended, the compounding ratio of the liquid crystal resin is such that the composition as a whole is in a concentration range where the liquid crystal resin can be made into fibers in the following extrusion molding process. It is necessary to adjust the concentration so that the phase inversion does not occur, and the compounding ratio of the liquid crystal resin varies depending on the kind of the thermoplastic resin in the composition.

Here, for example, when the thermoplastic resin is a polyamide resin, the compounding ratio of the composition is 40 to 80% by weight of the liquid crystal resin with respect to 60 to 20% by weight of the polyamide resin.

When the thermoplastic resin is an ABS resin, the composition is 30 to 75% by weight of liquid crystal resin with respect to 70 to 25% by weight of ABS resin.

When the thermoplastic resin is a polycarbonate resin, the compounding ratio of the composition is 3 to 70% by weight of liquid crystal resin to 93 to 30% by weight of the polycarbonate resin.
It is.

When the thermoplastic resin is polypropylene resin, the mixing ratio of the composition is polypropylene resin 9
The liquid crystal resin is 2 to 70% by weight with respect to 8 to 30% by weight.

When the thermoplastic resin is a polyethylene resin, the blending ratio of the composition is polyethylene resin 98 to
The liquid crystal resin content is 2 to 70% by weight with respect to 30% by weight.

[0019]

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

According to the method of the present invention, a liquid crystal resin (41) which is microscopically fiberized in the circumferential direction as shown in FIG.
A tubular body (55) made of a mixture of the thermoplastic resin (42) and the thermoplastic resin (42) and having improved circumferential strength and rigidity is obtained.

From the extruder (11) shown in FIG.
A mixture of (41) and a thermoplastic resin (42) having a melting point or melting temperature below the transition point of the liquid crystal resin (41) is extruded at a temperature above the transition point of the liquid crystal resin and connected to the extruder (11). Cylindrical first channel (31) in the crosshead die (12)
To be introduced.

Here, as shown in detail in FIG. 2, the crosshead die (12) has an outer die (21), and a rotary die (22) and a fixed inner die () inside the outer die (21). 23) and are paid.

That is, in FIG. 2, the crosshead die (12) is
Inside the cylindrical first flow path (31), a rotary mold (22) that rotates around a rotation axis extending in the same direction as the resin extrusion direction is arranged, and the outer periphery of the cylindrical first flow path (31) The surface is bounded by a fixed wall (21a) in the middle of the outer mold (21). Cylindrical first
The outer end of the crosshead die (12) (2
1) A mixture of a liquid crystal resin (41) and a thermoplastic resin (42) is introduced from a branch channel (33) provided inside.

Inside the rotary die (22), the small diameter portion (2) of the fixed inner die (23) arranged at the center of the crosshead die (12) is provided.
3a) is located. Further, the fixed wall portion on the outer periphery of the large diameter portion (23b) on the front end side in the extrusion direction of the fixed inner mold (23) constitutes a non-rotating cylindrical second flow path (32) described later.

The liquid crystal resin (41) and the thermoplastic resin
The liquid crystal resin (41) containing the mixture of (42) in the cylindrical first flow path (31).
Liquid crystal resin is formed into a tubular shape so that it is passed at a temperature above the liquid crystal transition point of
(41) forms a tubular molded body (43) oriented in the circumferential direction. In this case, the liquid crystal resin (41) is usually microscopically fiberized.

That is, the above thermoplastic matrix resin
A mixture of (42) and a liquid crystal resin (41) having a liquid crystal transition temperature higher than the melting point or melting temperature of the resin (42),
Extrusion molding is performed at a temperature equal to or higher than the liquid crystal transition point of the liquid crystal resin (41) at an apparent shear rate at which the liquid crystal resin (41) acts on the fibrous resin in the matrix resin (42).

Here, the apparent shear rate is 1 × 10.^Two
-10^Fives^-1, Preferably 3 × 10 ^Two-10^Fours^-1Toss
Need to be Blends that have undergone extrusion at shear rates in this range
The liquid crystal resin (41) in the composite resin composition is rotated by the rotary type (22).
Microscopically susceptible to fibrillation due to use.

Specifically, the outer die of the crosshead die (12)
(21) From the branch channel (33) provided inside to the cylindrical first channel
At the beginning of (31), the liquid crystal resin (41) and the thermoplastic resin (42)
When the mixture with and is extruded at a temperature equal to or higher than the liquid crystal transition point of the liquid crystal resin (41), the molten resin mixture is immediately attached from the rotary mold (22) inside the cylindrical first flow path (31) due to its adhesiveness. The mixture is moved so as to be pulled in the circumferential direction by the rotating rotary mold (22) without being separated, and the mixture is subjected to torsional shear due to rotation of the rotary mold, and the liquid crystal resin (41) is formed into fibers (fibrillation).
Also, the orientation of the fibrous material in the circumferential direction of the tubular shaped body is promoted, and the tubular shaped body (43) in which the liquid crystal resin (41) is oriented in the circumferential direction is formed.

The size of the gap of the cylindrical first flow path (31) is appropriately set according to the shape of the tubular molded body (43), particularly the wall thickness.

The rotary type (22) may be arranged on at least one of the inner and outer sides of the cylindrical first flow path (31).
For example, in FIG. 4, the rotary molds (22) and (22) are arranged on both inner and outer sides of the cylindrical first flow path (31).

Here, the rotation speed of the rotary mold (22) arranged inside and / or outside the first cylindrical flow path (31) is determined by the shape (outer diameter) of the tubular molded body (43) to be molded. , Inner diameter, wall thickness) and extrusion rate, and is not particularly limited, but a range of 1 to 200 rpm is suitable. By being rotated in this range, the liquid crystal resin (41) in the mixture is
A fiber having a diameter of 0.1 to 10 μm and an aspect ratio of 5 or more is likely to be formed.

When the rotary molds (22) are arranged on both inner and outer sides of the first cylindrical flow path (31), the rotary molds (22) on both inner and outer sides are arranged.
Rotate in the same or opposite directions. When the rotary molds (22) (22) arranged on both the inside and outside rotate in the same direction, it is necessary to provide a speed difference between the rotations of the molds (22) (22).

Also, the first cylindrical shape of the crosshead die (12)
Rotating type arranged inside and / or outside the flow path (31)
The rotation of (22) is performed by a rotation mechanism (not shown) provided on them.
And the motor (15) installed outside the crosshead die (12)
This is achieved by connecting a drive source such as the above through a rotary drive force transmission mechanism such as a belt or a chain.

The tubular molded body (43) containing the fibrous liquid crystal resin (41) thus formed by passing through the cylindrical first flow path (31) is
Next, it is guided into the non-rotating cylindrical second flow path (32) extending in the cylindrical first flow path (31).

Here, the cylindrical second flow path (32) is connected to the cylindrical first flow path (31), which is the fixed wall portion of the front end of the crosshead die outer die (21) in the extrusion direction. It is formed between (21b) and the large diameter portion (23b) of the fixed inner mold (23) inside thereof.

Then, the tubular molded body (43) containing the fibrous liquid crystal resin (41) is placed in the cylindrical second flow path (32) by the liquid crystal resin (43).
After passing at a temperature not higher than the transition point of (41) and not lower than the melting point or melting temperature of the thermoplastic resin (42), it is extruded from the outer die (21) outlet, and the fibrous liquid crystal resin (41) is oriented in the circumferential direction. The fiber-reinforced tubular body (44) is molded.

At this time, the mixture is in the cylindrical second flow path (32).
It is essential that the temperature range through which the liquid crystal passes through is not higher than the transition point of the liquid crystal resin (41). That is, when the temperature of the mixture is equal to or higher than the transition point of the liquid crystal resin (41), the liquid crystal resin microscopically fibrillated in the first flow path (31) portion in which the rotary mold (22) is arranged ( 41) changes to a granular dispersed state, which is not preferable.

The cross-sectional size of the outlet of the outer die (21) of the crosshead die (12) is not particularly limited and is appropriately selected according to the product.

As shown in FIGS. 2 and 4, the inside of the cylindrical first flow path (31) of the crosshead die (12) and / or
Alternatively, it is desirable to interpose a bearing (24) or the like as a sliding member on the contact surface between the rotary die (22) arranged outside and the fixed wall portion of the crosshead die outer die (21).

Further, the extruder (11) shown in FIG.
All conventionally known ones can be adopted, for example, 1
Extrusion is carried out using a twin-screw extruder.

The fiber reinforced tubular body (44) extruded from the crosshead die (12) is cooled at least to a temperature at which the shape and inner and outer diameters of the fiber reinforced tubular body (44) are not plastically changed at least in the drawing step. It is necessary to cool, and it is desirable to cool to ambient temperature (outside air temperature).

Here, as a means for cooling the fiber-reinforced tubular body (44) extruded from the crosshead die (12), as shown in FIG. 1, the fiber-reinforced tubular body (44) is placed in a water tank (14). A method of passing the inside of a refrigerant such as water, a method of applying cool air to the fiber reinforced tubular body (44) by a means such as a blower, a method of passing the fiber reinforced tubular body (44) through a cooling die through which the refrigerant flows, etc. And is appropriately set according to the dimensions of the tubular product (45) finally obtained and the molding process line.

As the take-up machine (15) for taking the cooled tubular product (45), a belt type take-up machine, a caterpillar type take-up machine, a take-up roll, etc. are appropriately used.

The tubular body product (45) shown in FIG. 3 manufactured by the method of the present invention will be described below.
Is a liquid crystal resin (41) microscopically fiberized inside the thermoplastic matrix resin (42) oriented in the circumferential direction, and the inner and outer diameters of the tubular body product (45) are It is appropriately set according to. However, in order to exert the effect of improving the strength and rigidity in the circumferential direction of the tubular product (45), the thickness of the tubular product (45) is preferably, for example, 1.0 mm or more, and usually 1.0 mm or more. ~ 30.0 mm.

According to the method of the present invention, the mixture of the liquid crystal resin (41) and the thermoplastic resin (42) having a melting point or a melting temperature lower than the transition point of the liquid crystal resin (41) is mixed with the extruder (11). ) From the cylindrical head of the crosshead die (12) connected to it
A rotary mold (22) which is introduced into the flow channel (31) and rotates on at least one of the inner and outer sides of the cylindrical first flow channel (31) around a rotation axis extending in the same direction as the resin extrusion direction. The liquid crystal resin (4) in the cylindrical first flow path (31).
The liquid crystal resin (4) was formed into a tubular shape so that it was passed at a temperature equal to or higher than the transition point of 1) and was subjected to torsional shear during the passage.
1) forms a tubular molded body (43) oriented in the circumferential direction, and this tubular molded body (43) is connected to the cylindrical first flow path (31) and has an inner peripheral surface and an outer peripheral surface fixed wall. It is introduced into the cylindrical second flow path (32) defined by the parts (21b) (23b), and the second flow path (32) is below the transition point of the liquid crystal resin (41) and the thermoplastic resin (4).
By passing the liquid crystal resin (41) at a temperature equal to or higher than the melting point or melting temperature of 2) to form the fiber-reinforced tubular body (44) in which the liquid crystal resin (41) is oriented in the circumferential direction, the liquid crystal resin (4
1) is microscopically fibrillated (fiberized), and the liquid crystal resin (4
It is possible to obtain a tubular product (45) in which 1) is efficiently oriented in the circumferential direction, and further, strength and rigidity in the circumferential direction are improved.

[0046]

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

Example 1 A tubular product (45) comprising a fibrous liquid crystal resin (41) and a thermoplastic resin (42) shown in FIG. 3 was produced by the method of the present invention.

In FIG. 1, a liquid crystal resin is fed from the extruder (11).
(41) and a mixture of a thermoplastic resin (42) having a melting point or melting temperature below the transition point of the liquid crystal resin (41), extruded at a temperature above the transition point of the liquid crystal resin (41), the extruder ( 11)
It is introduced into the cylindrical first flow path (31) in the crosshead die (12) connected to.

Inside the cylindrical first flow path (31), a rotary die (22) which rotates about a rotation axis extending in the same direction as the resin extrusion direction is arranged, and the cylindrical first flow path (31) The outer peripheral surface of 31) is demarcated by a fixed wall portion (21a) in the middle portion of the outer die (21).

Here, as the liquid crystal resin (41), an aromatic polyester liquid crystal polymer (trade name: Vectra A950, manufactured by Polyplastics Co., Ltd.) was used. The transition point of the liquid crystal resin (41) measured by DSC (Differential Scanning Calorimeter) was 28
1 ° C.

As the thermoplastic resin (42), high density polyethylene (trade name HE420, manufactured by Mitsubishi Plastics Co., Ltd.) was used. Similarly, the thermoplastic resin (4
The melting point of 2) was 134 ° C.

The mixing ratio of both resins (41) and (42) was 80% by weight of the high-density polyethylene resin (42) and the ratio of the liquid crystal resin (4)
1) 20% by weight

In the above, first, both resins (41) and (42) are mixed in a pellet state, and then the mixed resin composition is mixed with a crosshead die (12) using a twin screw extruder (11) having a screw diameter of 30 mm. Was set to 290 ° C.

Then, as shown in FIG. 2, the liquid crystal resin (41)
The mixture of the thermoplastic resin (42) with the crosshead die (1
It is expanded into a cylindrical shape from the branch passage (manifold) (34) of 2) and is extruded into the cylindrical first flow passage (21). At this time, the rotary die (22) is crosshead die (14). It is rotated by the driving force of the motor (13) installed outside the
The rotation speed of 2) was set to 50 rpm.

A mixture of the liquid crystal resin (41) and the thermoplastic resin (42) is passed through the first cylindrical flow path (31) at a resin temperature of 290 ° C. and is subjected to torsional shear during the passage. The liquid crystal resin (41) was formed into a tubular shape to form a tubular molded body (43) in which the liquid crystal resin (41) was oriented in the circumferential direction.

That is, the above thermoplastic matrix resin
The mixture of (42) and the liquid crystal resin (41) is a liquid crystal resin (41).
Extrusion molding was carried out at a temperature equal to or higher than the liquid crystal transition point of, at an apparent shear rate at which the liquid crystal resin (41) acts on the resin that becomes microscopically fibrous in the matrix resin (42).

As a result, the mixture is subjected to torsional shearing due to the rotation of the rotary mold (22), and the liquid crystal resin (41) is fibrillated (fibrillated) and the fiberized product is oriented in the circumferential direction of the tubular molded body. Thus, a tubular molded body (43) in which the fibrous liquid crystal resin (41) was oriented in the circumferential direction was formed.

Next, the tubular molded body (43) is provided with a cylindrical second flow passage (32) extending in the cylindrical first flow passage (31) and not rotating.
Led inside. The cylindrical second flow path (32) includes a fixed wall portion (21b) at the front end of the crosshead die outer die (21) in the extrusion direction, and a large diameter portion (23b) of the inner fixed die (23) inside thereof. And the outer diameter of the large diameter portion (23b) of the fixed inner mold (23) on the inner peripheral surface of the cylindrical second flow path (32) is 90 mm, and the second flow path (32) Fixed wall part on the outer surface of the crosshead die outer die (21) at the front end in the extrusion direction
(21b) The inner diameter is 100 mm, and the inside of the second flow path (32) is 2 mm.
The temperature was adjusted to 50 ° C.

The cylindrical second channel (3) of the crosshead die (12)
The fiber-reinforced tubular molded product (43) that has passed through 2) is then cooled in a cooling tank.
It was cooled to room temperature by (14) and taken by a take-up machine (15) to obtain a tubular product (45) having an outer diameter of 100 mm and an inner diameter of 90 mm.

The liquid crystal resin (41) in the tubular product (45) thus formed was fibrous with a diameter of about 0.1 to 10 μm and an aspect ratio of 5 or more. This is a magnification of 200
It was confirmed by observing with a 0-times micrograph.

Example 2 As the thermoplastic resin (42), a vinyl chloride resin having a melting temperature of 170 ° C. (containing 2 parts by weight of a tin stabilizer and 1 part by weight of a lubricant) was used, and a liquid crystal resin (41) was prepared. Aromatic polyester liquid crystal polymer (Product name: Rod Run LC300
0, manufactured by Unitika Ltd.) was used. Similarly, the transition temperature of the liquid crystal resin (34) measured by DSC was 180 ° C.

A resin mixture composition containing 20% by weight of this liquid crystal resin (34) was used in a cylindrical shape in which a rotary mold (22) was arranged inside using the same crosshead die (12) as in Example 1. It is formed between the fixed wall portion (21b) at the front end of the die outer die (21) and the large diameter portion (23b) of the fixed inner die (23) with the temperature in the first channel (31) set to 200 ° C. Example 1 except that the temperature in the non-rotating cylindrical second flow path (32) was set to 170 ° C., respectively.
In the same manner as in, a tubular product (45) having the fibrous liquid crystal resin (41) oriented in the circumferential direction was produced.

Comparative Example 1 For comparison, a tubular product was manufactured in the same manner as in Example 1 except that the liquid crystal resin (41) was not added to the thermoplastic resin (42). .

Comparative Example 2 The same procedure as in Example 1 was repeated except that the rotary mold (22) was not rotated in the cylindrical first flow path (31) of the crosshead die (12). Manufactured body products.

Comparative Example 3 For comparison, a tubular product was produced in the same manner as in Example 2 except that the liquid crystal resin (41) was not added to the thermoplastic resin (42). .

Comparative Example 4 The same procedure as in Example 2 was repeated except that the rotary mold (22) was not rotated in the cylindrical first flow path (31) of the crosshead die (12). Manufactured body products.

Evaluation of Molded Articles Next, in order to evaluate the performance of the tubular products obtained in the above Examples and Comparative Examples, that is, the molded products, tubular products each having a length of 40 mm were obtained from the obtained tubular products. The sample was cut out, and each sample was subjected to hot press molding at a temperature not higher than the transition temperature of each liquid crystal resin to prepare a sheet-shaped sample.

The tensile test of the sheet-like sample thus obtained in the direction corresponding to the circumferential direction of the tubular product was conducted according to ASTM.
The tensile strength and the tensile elastic modulus in the circumferential direction were measured according to D638, and the obtained results are summarized in Table 1 below.

[0069]

[Table 1] As is clear from the results of Table 1 above, according to the examples of the present invention, the fibrous liquid crystal resin (41) mixed in the thermoplastic resin (42) is efficiently oriented in the circumferential direction. However, the tensile strength and the tensile elastic modulus in the circumferential direction of the obtained tubular body product (45) were very large, and had sufficient strength and rigidity.

On the other hand, in the tubular products of Comparative Examples, the tensile strength and tensile elastic modulus in the circumferential direction were small, and the strength and rigidity were insufficient.

[0071]

As described above, in the method for producing a tubular body of the present invention, a mixture of a liquid crystal resin and a thermoplastic resin having a melting point or a melting temperature lower than the transition point of the liquid crystal resin is mixed by an extruder. Is introduced into the cylindrical first flow path of the crosshead die connected to and is rotated about a rotation axis extending in the same direction as the resin extrusion direction on at least one of the inner and outer sides of the cylindrical first flow path. A rotary mold is placed, and the mixture is tubularly shaped so as to pass through the cylindrical first flow path at a temperature equal to or higher than the transition point of the liquid crystal resin and undergo torsional shearing during the passage. A liquid crystal resin forms a tubular molded body that is oriented in the circumferential direction, and this tubular molded body is connected to the cylindrical first flow path, and a cylindrical second body whose inner peripheral surface and outer peripheral surface are defined by a fixed wall portion is formed. Introduced into the flow channel, the second flow channel transfers the liquid crystal resin Since the liquid crystal resin is molded into a fiber-reinforced tubular body in which the liquid crystal resin is oriented in the circumferential direction by passing it at a temperature equal to or higher than the melting point or melting temperature of the thermoplastic resin, the resulting tubular body product is microscopic. The fibrillated liquid crystal resin will be reliably aligned in the circumferential direction,
Therefore, the tubular product has excellent strength and rigidity in the circumferential direction.

Therefore, the molded article of the tubular body manufactured by the method of the present invention has an effect that it can be suitably used for various pipes, poles and the like which require strength and rigidity.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an example of an apparatus for carrying out the method for manufacturing a tubular body of the present invention.

FIG. 2 is an enlarged perspective sectional view of an essential part of a crosshead die used in the apparatus of FIG.

FIG. 3 is a partially enlarged perspective view of a tubular body manufactured by the apparatus of FIG.

FIG. 4 is an enlarged perspective sectional view of an essential part showing another example of the apparatus for carrying out the method for manufacturing a tubular body of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Extruder 12 Crosshead die 13 Drive motor 14 Cooling tank 15 Take-up machine 21 Crosshead die Outer mold 21a Fixed wall part of middle part of outer mold 21b Fixed wall part of front end part of outer mold 22 Rotating mold 23 Fixed inner mold 31 Cylindrical First channel 32 Cylindrical second channel 33 Branch channel 41 Liquid crystal resin 42 Thermoplastic resin 43 Tubular molded body 44 Fiber reinforced tubular body 45 Tubular body product

Claims (1)

[Claims] 1. A cylindrical first flow path of a crosshead die, in which a mixture of a liquid crystal resin and a thermoplastic resin having a melting point or a melting temperature lower than the transition point of the liquid crystal resin is connected thereto by an extruder. And a rotary mold that rotates about a rotation axis extending in the same direction as the resin extrusion direction is disposed on at least one of the inner and outer sides of the cylindrical first flow path,
The mixture was tubularly shaped so as to pass through the first cylindrical flow path at a temperature equal to or higher than the transition point of the liquid crystal resin, and to undergo torsional shear during the passage, and the liquid crystal resin was oriented in the circumferential direction. A tubular molded body is formed, and then this tubular molded body is introduced into the cylindrical second flow path which is continuous with the cylindrical first flow path and whose inner peripheral surface and outer peripheral surface are defined by the fixed wall portion, The fiber-reinforced tubular body in which the liquid crystal resin is oriented in the circumferential direction is formed by passing the second flow path at a temperature not higher than the transition point of the liquid crystal resin and not lower than the melting point or melting temperature of the thermoplastic resin. A method for manufacturing a tubular body.