JPH07205276A - Method and apparatus for producing synthetic resin stick - Google Patents

Abstract

PURPOSE:To enhance productivity by efficiently and stably heating a rod at the time of stretching treatment in an apparatus for producing a small diameter stick by stretching treatment. CONSTITUTION:An extrusion molding machine 22 is constituted of an extruder 26, a first cooling tank 29 cooling the molten resin 27 extruded from the extruder 26 and a rod haul-off machine 30 taking over a rod 28 at predetermined speed. The rod haul-off machine 30 is constituted of a urethane drive roller 32 and a tension roller 33. A stretching treatment apparatus 23 is constituted of a heating furnace 34 having a far infrared heater as a heating source, a second cooling tank 36 cooling a stretched stick 35 and a stretching haul-off machine 37 taking over the stick 35 at the predetermined speed corresponding to stretching magnification. An annealing treatment apparatus 24 is constituted of an annealing furnace 40, a third cooling tank 41 cooling the annealed stick 35 and an annealing haul-off machine 42 taking over the stick 35 at the predetermined speed corresponding to a shrinkage factor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin stick manufacturing method and apparatus for manufacturing small diameter solid or hollow sticks made of synthetic resin.

[0002]

2. Description of the Related Art For example, in the case of a cotton swab shaft or a kitchen bowl, in recent years, a synthetic resin stick such as polypropylene has been used in place of the conventional paper or bamboo stick. There is. Such a synthetic resin stick is inferior in physical properties (flexural strength, flexural elasticity) in the bending direction to a simple extrusion molded product. Manufacturing sticks has been done.

As a technique for obtaining a synthetic resin stick by such a stretching treatment, for example, Japanese Patent Application Laid-Open No. 4-33262 is known.
There is one disclosed in Japanese Patent No. 4 publication. As shown in FIG. 3, the manufacturing apparatus disclosed in this publication comprises an extruder 1, a cooling tank 2 and a take-up machine 3, and extrudes a raw material made of a crystalline polypropylene resin having an MFR of 0.5 to 20. It comprises an extrusion molding part 5 for obtaining a large diameter rod 4 and a heating device 6, a cooling tank 7 and a take-off device 8. The rod 4 obtained by the extrusion molding device 5 is stretched by a factor of 6 or more to have a small diameter. The sticking section 10 for obtaining the stick 9 is continuously provided.

[0004]

However, in the above-described conventional apparatus, hot air is used as the heating source of the heating device 6 in the stretching treatment section 10, and a plurality of torch nozzles 11 to 4 are arranged around the rod 4. Since the configuration is such that the hot air is supplied toward, the heating state of the rod 4 becomes non-uniform, and there is a problem that the stretching point is not stable. If the stretching point is not stable in this way, the stick 9 having a uniform diameter cannot be obtained. Further, in heating with hot air, it is difficult to concentrate heat energy for heating the rod 4, and there is a drawback that the thermal efficiency is poor.

In this type of resin molded product, it is generally necessary to perform annealing for removing the internal strain generated at the time of molding.
The stick 9 sent out from the take-up machine 8 of the stretching processing section 10 is cut into a predetermined length by the cutting machine 12 in the next stage, and then a large number of cut products (sticks) are put together. Since it is housed in an annealing furnace for annealing, productivity is poor and
There was a drawback that the product dimensions varied due to shrinkage accompanying annealing.

In the manufacturing apparatus shown in FIG. 3, the take-up machine 3 and the take-up machine 8 sandwich the rod 4 and the stick 9 with the belt 13 and take them up.
In the case of using No. 3, since the rod 4 and the stick 9 have a small diameter and a small contact area, it is necessary to increase the clamping force. As a result, the partial wear is severe and the life is extremely short, and the replacement is frequently performed. There were also defects that had to be taken.

The present invention has been made in view of the above circumstances, and an object thereof is to produce a solid or hollow stick having a small diameter by a stretching treatment, and to efficiently and stably secure a rod during the stretching treatment. The present invention provides a method and an apparatus for manufacturing a synthetic resin stick, which can be heated at high temperature and is excellent in productivity.

[0008]

The method for producing a synthetic resin stick according to the present invention is a method for producing a solid or hollow synthetic resin stick having a small diameter, which comprises extruding a synthetic resin raw material to a predetermined diameter. An extrusion molding step of molding the rod, and a stretching treatment step of heating and softening the rod with a far infrared heater to perform a stretching treatment to obtain a stick having a predetermined diameter,
The invention is characterized in that the annealing treatment step for annealing the stick is continuously performed (the invention of claim 1).

The production of the synthetic resin stick of the present invention is an apparatus for producing a solid or hollow synthetic resin stick having a small diameter, and an extruder for melting and extruding a synthetic resin raw material from a die. A first cooling tank for cooling the molten resin extruded from the extruder while sizing, and the molten resin extruded from the extruder as the first cooling tank.
, A rod take-out machine for drawing the rod through a cooling tank at a predetermined speed to form a rod having a predetermined diameter and sending the rod to a subsequent stage, a heating furnace for heating and softening the rod by a far infrared heater, and a stretched rod. And a second cooling tank for cooling the rod, and the rod sent from the rod take-up machine is drawn through the heating furnace and the second cooling tank at a predetermined speed according to the draw ratio while passing through the heating furnace and the second cooling tank. A drawing take-off device for drawing the stick and sending the stick to the subsequent stage, an annealing furnace for heating the stick for annealing, a third cooling tank for cooling the annealed stick, and An annealing pull that takes the stick sent out from the drawing take-out machine through the annealing furnace and the third cooling tank at a predetermined speed according to the shrinkage rate. Where to and a machine continuously having features (the invention of claim 2).

In this case, it is more effective if the rod take-up machine and the drawing take-out machine are constructed so as to take up the rod and the stick by means of urethane rollers (the invention of claim 3).

[0011]

According to the method for producing a synthetic resin stick according to claim 1 of the present invention, in the extrusion molding step, the synthetic resin raw material is extruded to form a rod having a predetermined diameter, and then in the stretching treatment step, The rod is stretched into a stick with a predetermined diameter, and in the next annealing step,
The stick is annealed.

At this time, it is generally known that the synthetic resin material has a very high heat absorption rate of far infrared rays, and in the drawing treatment step, the infrared heater is used to heat and soften the rod. It is possible to heat efficiently and stably. Also, extrusion molding, stretching treatment,
Since the annealing process is performed continuously, it is possible to obtain excellent productivity and to make the shrinkage rate of the stick due to annealing constant and to obtain a product of uniform dimensions. Become.

According to the synthetic resin stick manufacturing apparatus of the second aspect of the present invention, the molten resin extruded from the extruder is taken by the rod take-out machine through the first cooling tank at a predetermined speed. Thus, a rod having a predetermined diameter is formed. Subsequently, the formed rod is drawn at a predetermined speed according to the draw ratio while passing through the heating furnace and the second cooling tank in order by the drawing machine for drawing, thereby obtaining a drawn stick having a given diameter. . further,
The drawn stick is passed through an annealing furnace and a third cooling tank by an annealing take-up machine and taken at a predetermined speed according to the shrinkage ratio, whereby annealing of the stick is performed and a stick having a predetermined diameter is obtained. To be

At this time, since the heating furnace for the stretching treatment is equipped with an infrared heater for heating and softening the rod, the rod can also be heated efficiently and stably. In addition, since extrusion molding, stretching treatment and annealing are carried out continuously, the productivity is excellent and the shrinkage rate of the stick accompanying annealing can be made constant, and it is possible to obtain a product of uniform size. .

In the synthetic resin stick manufacturing apparatus of the present invention, the rod take-up machine and the drawing take-out machine are
If the rod and the stick are configured to be pulled by the urethane roller (the invention of claim 3), the elasticity of the urethane roller will hold the rod and the stick with a strong force without damaging or deforming the rod or the stick. can do. In addition, urethane rollers are less likely to wear compared to when using a belt, and can withstand long-term use.Furthermore, the driving force is smaller than the belt type, and the motor size is smaller. Therefore, the area occupied by the take-off machine can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 schematically shows the overall structure of a synthetic resin stick manufacturing apparatus 21 according to this embodiment. In this embodiment, for example, an outer diameter of polypropylene resin as a main component is about 1 to 5 mm. It is designed to produce solid or hollow synthetic resin sticks.

This manufacturing apparatus 21 is roughly classified into an extrusion molding apparatus 22 for extruding a synthetic resin raw material to form a rod having a predetermined diameter, and a heating treatment for softening the rod by a far infrared heater to draw it to a predetermined diameter. Of the stick, and an annealing device 24 for annealing the stick are continuously provided.

Among them, the extrusion molding device 22 is a well-known extruder 26 that heats and melts a synthetic resin raw material and continuously extrudes it from a circular or ring-shaped die 25, and this extruder 26.
The first cooling tank 2 for cooling the molten resin 27 extruded from the cooling water with the cooling water to harden the molten resin 27 into the rod 28 having a predetermined diameter.
9 and the molten resin 27 (rod 28) extruded from the extruder 26 are taken through the first cooling tank 29 at a predetermined speed, and the rod 28 is stretched in the subsequent stage stretching device 2
3 and a rod take-off machine 30 for sending the rod to the No. 3 in order. Further, at the tip of the first cooling tank 29,
A sizer 31 for sizing the molten resin 27 is provided.

The rod retractor 30 is provided with two driving rollers 32, 32 driven by a motor (not shown) whose speed is adjustable, and a nipping force positioned above the driving rollers 32, 32, respectively. The tension rollers 33 and 33 that can be adjusted are provided, and the rod 28 is sandwiched between them and pulled. In addition, in this embodiment, each of the rollers 32 and 33 is elastic and has the rod 2
There is little slippage between 8 and it is made of urethane that can hold with strong force. The synthetic resin raw material is, for example, a thermoplastic crystalline resin containing polypropylene as a main component, a synthetic resin material obtained by mixing 1 to 20% of a thermoplastic amorphous resin such as a liquid crystal polymer, and an inorganic filler such as calcium carbonate. 2 to 15% is added to the composition.

Next, the stretching apparatus 23 comprises a heating furnace 34 for heating and softening the rod 28 to a stretchable state, and a stretched rod 28 cooled with cooling water to be hardened and hardened. And the rod 28 (stick 35) while passing through the heating furnace 34 and the second cooling tank 36 at a predetermined speed according to the draw ratio, and the stick. The drawing take-out device 37 for feeding 35 to the subsequent annealing device 24 is provided in this order.

As shown in FIG. 2, the heating furnace 34 has a tunnel-like shape having a circular cross section, and is provided with a plurality of arc-shaped far infrared ray heaters 38 on its inner wall. . The rod 28 is adapted to pass through the central portion of the heating furnace 34, and the far infrared heaters 3
The heat rays having a wavelength of 3.3 to 3.7 μm emitted from the No. 8 are configured to be concentrated toward the central portion in the heating furnace 34. In addition, the drawing take-up machine 37 is a stick 3
For example, five rollers 39, which are also made of urethane for sandwiching 5 and are picked up, are configured to rotate by a motor whose speed can be adjusted. In this case, the rollers 39 are vertically arranged in a so-called zigzag pattern. .

Finally, the annealing device 24 includes an annealing furnace 40 for heating the stick 35 to an annealing temperature for annealing and a first annealing furnace 40 for cooling the annealed stick 35 with cooling water to cure the stick 35. The cooling bath 41 of No. 3 and the annealing take-up device 42 that takes in the stick 35 sent from the drawing take-out device 37 through the annealing furnace 40 and the third cooling bath 41 at a predetermined speed according to the shrinkage ratio are sequentially provided. It is equipped with.

In this case, although not shown, the annealing furnace 4
No. 0 also has a circular tunnel shape, and is configured to perform heating using both far-infrared rays and near-infrared rays by a heater disposed on the inner wall portion thereof. Although not shown in detail, the annealing take-up machine 42 is also configured to take the stick 35 by rotating the roller 43 at a predetermined speed by a motor whose speed can be adjusted. Further, the annealing take-up machine 42 is incorporated with a cutter 44 for cutting the stick 35 into a predetermined length.

Next, the manufacturing apparatus 2 configured as described above.
A manufacturing procedure of the synthetic resin stick 35 according to No. 1 will be described. First, in the extrusion molding device 22, the extrusion molding process is executed as follows. That is, from the die 25 of the extruder 26 to the molten resin 27 having a circular or ring-shaped cross section.
Are continuously extruded, and the molten resin 27 is drawn by the rod take-off device 30 toward the right side in the figure at a predetermined speed. During this time, the molten resin 27 is cooled by passing through the cooling water in the first cooling tank 29 and cured while the shape of the molten resin 27 is adjusted by the sizer 31, and the long rod 2 having a predetermined diameter is obtained.
8 is continuously sent out from the rod retractor 30.

At this time, the rod 28 is attached to the drive roller 3
The roller 3 made of urethane is taken in a state of being sandwiched between the 2, 2 and the tension rollers 33, 33.
Due to the elasticity of Nos. 2 and 33, the rod 28 can be held with a strong force without being damaged or deformed, and the rod 28 can be pulled with less slippage. Further, the urethane roller is less worn than when a belt is used, and can withstand long-term use. Further, the driving force is smaller than that of the belt system, and the motor can be small in size, and the area occupied by the take-up machine 30 can be reduced.

The outer diameter of the rod 28 is a value obtained by multiplying the final outer diameter (1 to 5 mm) of the target stick 35 by the square root of the target stretching ratio (7 to 15 times). The diameter of the die 25, the extrusion amount of the extruder 26, the take-up speed of the rod take-up machine 30, and the like are determined based on the setting.

Subsequently, the stretching treatment device 23 carries out a stretching treatment process for the rod 28 fed from the rod retractor 30. That is, the rod 28 is continuously drawn by the drawing device 37 for stretching at a predetermined speed. At this time, the rod 28 is drawn by the device 3 for rod.
After being sent from 0 to the first half of the heating furnace 13,
It is fed slowly with almost the same diameter, gradually softens by being heated in the heating furnace 34, and finally is softened to a state where it can be stretched at the end portion (stretching point P) of the heating furnace 34. . Then, the softened rod 28 is stretched by being stretched at the stretching point P at a high speed,
The stick 35 having a small diameter is passed through the cooling water in the second cooling tank 36 to be cooled and cured, and the stick 35 having a predetermined diameter is fixed in shape.

In this case, it is known that the synthetic resin material forming the rod 28 has a heat absorption rate of about 100% for far infrared rays having a wavelength of 3.3 to 3.7 μm, and the heating furnace 34 is used. Far-infrared heater 38 as a heating source for
In addition to adopting the above, the heat ray is collected toward the central portion of the heating furnace 34 through which the rod 28 passes, so that the thermal efficiency becomes extremely high and stable heating can be performed.
The stretching point P can be stabilized.

Further, since the stretching take-up device 37 is also constructed to take up the stick 35 by the urethane roller 39, like the rod take-up device 30,
The stick 35 can be held with a strong force without being damaged or deformed.
Can be picked up with little slippage, and further,
It can withstand long-term use. still,
The take-up speed of the drawing take-up machine 37 is set to be slightly higher than the speed obtained by multiplying the take-up speed of the rod take-up machine 30 by a target draw ratio. this is,
This is because the contraction (for example, about 5%) in the length direction of the stick 35 due to the subsequent annealing process is taken into consideration.

Finally, the annealing process is continuously performed by the annealing device 24 on the stick 35 that has been stretched as described above. That is, the stick 35 sent out from the drawing take-up machine 37 is slightly faster than the drawing speed of the drawing take-out machine 37 (for example, about 5%).
It is continuously drawn by the annealing take-up machine 42 at a slow speed. At this time, the stick 35 contracts with the internal strain by being heated to a predetermined annealing temperature in the annealing furnace 40, and then the internal strain is passed by being passed through the cooling water of the third cooling tank 41. The shape is fixed in the removed state.

Also in this case, since the far infrared rays and the near infrared rays are used together as the heating source of the annealing furnace 40, the stick 35 can be efficiently and evenly heated, and stable annealing can be performed. It can be done. As a result, the stick 35 having a predetermined outer diameter dimension that has been stretched to the target stretch ratio can be obtained. The obtained stick 35 is cut into a predetermined length by a cutter 44 to obtain a product.

As described above, according to this embodiment, the rod 28
Since the far-infrared heater 38 is used as the heating source of the heating furnace 34 for performing the drawing process of 1., unlike the conventional one using hot air as the heating source of the heating device 6, the rod 28 made of synthetic resin is efficiently and efficiently used. Can be heated stably,
As a result, the stretching point P can be stabilized to form the uniform stick 35.

Further, since the extrusion molding process, the stretching process and the annealing process are continuously performed, a large number of conventional products which have been once cut are put together in an annealing furnace for annealing. Unlike the conventional method, excellent productivity can be obtained and a product can be obtained in a short time, and the shrinkage rate of the stick 35 accompanying annealing can be made constant, so that a uniform size can be obtained. It is possible to obtain the product.

In this embodiment, in particular, the rod take-up device 30 and the drawing take-up device 37 are replaced by the urethane roller 3
2, 33, 39 by rod 28 and stick 35
Therefore, unlike the conventional one using the belt 13, the urethane rollers 32, 33,
Due to the elasticity of 39, the rod 28 and the stick 35 can be held with a strong force without being damaged or deformed, and the rod or stick can be taken in with less slippage. Further, compared to the case where the belt 13 is used, it is less worn and can be used for a long period of time. Further, the driving force is smaller than that of the belt system, and the motor can be small, so that the take-up machine 3
The occupied area of 0 can be reduced. As a result, the cost can be reduced and the device can be downsized as compared with the conventional one using the belt 13.

The present invention is not limited to the above-mentioned embodiment, and various raw materials can be adopted as the synthetic resin raw material, and the rod pulling machine 30 and the stretching pulling machine 37 can be used. , Not necessarily urethane roller 3
The present invention can be carried out by appropriately changing it within a range not departing from the gist such that the intended purpose can be achieved without using 2, 33 and 39.

[0036]

As is apparent from the above description, the present invention has the following excellent effects.
That is, according to the method for producing a synthetic resin stick of the present invention (the invention of claim 1), there is provided a method for producing a solid or hollow stick having a small diameter by a stretching treatment, which comprises extrusion molding and stretching with a far infrared heater. Since the treatment and annealing steps are continuously performed, the rod can be efficiently and stably heated during the stretching treatment, and the productivity is excellent.

According to the synthetic resin stick manufacturing apparatus of the present invention (the invention of claim 2), there is provided an apparatus for manufacturing a small-diameter solid or hollow stick by a drawing process, wherein a rod is provided by a far infrared heater. Since a heating furnace for heating and softening the rod is provided, and an annealing furnace for performing annealing, a third cooling tank, and an annealing take-up machine are continuously provided, the rod can be efficiently and stably drawn during the drawing process. It can be heated and has excellent productivity.

In this case, if the rod take-up machine and the drawing take-out machine are constructed so that the rods and sticks are drawn by urethane rollers (the invention of claim 3), the rods and sticks may be damaged or deformed. Without doing
It can be held with a strong force, can withstand long-term use, and has a smaller motor.
The device can be downsized.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and is a vertical cross-sectional front view schematically showing the overall configuration of a manufacturing apparatus.

[Fig. 2] Vertical side view of the heating furnace

FIG. 3 is a view corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

In the drawings, 21 is a manufacturing apparatus, 22 is an extrusion molding apparatus, 23 is a stretching processing apparatus, 24 is an annealing processing apparatus, 25 is a die,
26 is an extruder, 27 is a molten resin, 28 is a rod, 29 is a first cooling tank, 30 is a rod take-up machine, 31 is a sizer, 32 is a drive roller, 33 is a tension roller, 34
Is a heating furnace, 35 is a stick, 36 is a second cooling tank, 3
Reference numeral 7 is a drawing taker, 38 is a far infrared heater, 39 is a roller, 40 is an annealing furnace, 41 is a third cooling tank, 42 is an annealing taker, 43 is a roller, and 44 is a cutter.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area B29L 23:00

Claims (3)

[Claims] 1. A method for manufacturing a small-diameter solid or hollow synthetic resin stick, comprising: an extrusion molding step of extruding a synthetic resin raw material to form a rod having a predetermined diameter; and a far infrared heater for the rod. A method for producing a synthetic resin stick, characterized in that a stretching treatment step of heating and softening by means of a stretching treatment to obtain a stick having a predetermined diameter, and an annealing treatment step of annealing the stick are continuously performed. . 2. An apparatus for producing a small-diameter solid or hollow synthetic resin stick, comprising: an extruder for heating and melting a synthetic resin raw material and extruding it from a die; and a molten resin extruded from this extruder. A first cooling tank for cooling while sizing, and a molten resin extruded from the extruder are taken at a predetermined speed through the first cooling tank to form a rod having a predetermined diameter, and the rod is moved to a subsequent stage. A rod take-out machine for sending out, a heating furnace for heating and softening the rod by a far infrared heater, a second cooling tank for cooling the stretched rod, and a rod sent out from the rod take-out machine. While passing through the heating furnace and the second cooling tank in order, the stick for drawing is drawn at a predetermined speed according to the draw ratio to draw a stick having a predetermined diameter, and the stick is sent to the subsequent stage. An annealing furnace for heating and annealing the stick, a third cooling bath for cooling the annealed stick, and a stick sent from the drawing take-out machine for the annealing furnace and An apparatus for manufacturing a synthetic resin stick, comprising: an annealing take-up machine, which continuously draws through a third cooling tank at a predetermined speed according to the shrinkage rate. 3. The synthetic resin stick manufacturing apparatus according to claim 2, wherein the rod take-up machine and the drawing take-out machine are configured to take up the rod and the stick by means of urethane rollers. .