KR950006117B1 - Heat treatment method and apparatus for synthetic resin articles - Google Patents

Abstract

The method for increasing the productivity and quality in manufacturing the self temp. controlled polymer heating element, repeats the heating and cooling process in a short while. The heating element is only linearly moved at the heating state, and is rotated and bent at the cooling state. The apparatus comprises more than two of pulleys separated from each other; a tunnel-type heat-treating oven positioned between two pulleys; a cooling device positioned between the exit of the oven and the pulley; and a resistance monitoring device for measuring the cooled polymer heating element.

Description

Repeating, Continuous Heat Treatment Method, and Heat Treatment Apparatus for Autonomous Temperature Controlled Polymer Heating Element

1 is a schematic cross-sectional view of a repeating, continuous heat treatment apparatus of the present invention.

2 is a perspective view showing the structure of the tunnel-type heat treatment oven of the present invention.

3 is a front view and a side view showing the structure of the pulley of the present invention.

4 is a schematic diagram showing the structure of the resistance monitoring electrode of the present invention and the arrangement thereof.

5 is a graph showing a resistance reduction state according to the number of heat treatment repetitions using the repetitive and continuous heat treatment apparatus of the present invention.

* Explanation of symbols for main parts of the drawings

1: Tunnel type heat treatment oven 2: Support roller

3: heater 4: left pulley

5: right pulley 6: discharger

7: winder 8: cooling device

9: fan 10: resistance monitoring electrode

11: resistance meter 12: computer

13: heating element 14: inlet

15 outlet 16: oven lid

17: contact electrode

The present invention relates to a heat treatment process during the manufacturing process of the autonomous temperature controlled polymer heating element, and more particularly, to an iterative, continuous heat treatment method and improvement of the heat treatment apparatus which can greatly improve the uniformity of productivity and quality.

The heat treatment process plays a very important role in the manufacturing process of the autonomous temperature controlled polymer heating element. First, the conductive path of carbon black is formed in the heating element to reduce the resistance of the product. Through the heat treatment process, the product of the desired output can be manufactured by reducing the resistance of the product to a desired level. Second, it stabilizes the mechanical, electrical and thermal properties of the product so that it can produce a constant output even in long-term use.

Conventionally used in such a heat treatment process can be largely divided into a batch method and a continuous method.

As a batch heat treatment method, a product was put into a heated oven for a predetermined time, or as previously applied, a method of monitoring a decrease in resistance of a product during heat treatment and stopping the heat treatment when a desired level was reached was used. The method has the advantage of accurately adjusting the resistance value of the product, but has the disadvantage of low productivity.

On the other hand, the continuous heat treatment method enables continuous production and provides a uniform heat treatment condition in the length direction of the product, thereby obtaining a product with high productivity and uniform characteristics. Since it could not be infinitely long, a way to reduce the length of the tunnel had to be sought. One method of this is to reciprocate a product by using a pulley in an oven to obtain a relatively long heat treatment time even in a narrow space oven. Since the product is in close contact with the pulley rotates there was a disadvantage that the deformation occurs. As another method, as previously applied, the continuous heat treatment method using the rotational and sliding motions of the cylindrical drum is carried on the chain with a certain curvature so that the product does not deform and heat treatment is possible for a relatively long time. The structure of the complex and there was a problem that the equipment is worn out for a long time use.

Another disadvantage of the conventional continuous heat treatment method is that the heat treatment is performed after the insulation jacket is put on the heating element to have a higher melting temperature than the heat treatment temperature to prevent deformation of the product. There was a problem that can not know whether the heat treatment is proceeding to the desired level during the heat treatment operation.

In order to solve the problems of the conventional continuous heat treatment method, the present invention can be repeatedly repeated heating and cooling, and a repetitive, continuous heat treatment apparatus having a long time heat treatment effect and no deformation in the product and It is an object to provide the heat treatment method.

The heat treatment method of the present invention is configured to repeat the heating and cooling several times for a relatively short time, based on the fact that if the heating and cooling for a relatively short time is repeated several times, the heat treatment effect is similar to that of the one-time heat treatment for a long time. In addition, it is configured so that only linear motion is performed in a heated state of high temperature during heat treatment, and rotation and bending motion are performed only in a cooled state so that deformation does not occur in the product.

In addition, the heat treatment apparatus of the present invention and two or more pulleys having a rotation axis parallel to each other; A tunnel heat treatment oven located between the pulleys; A cooling device located between the outlet of the heat treatment oven and any one of the pulleys; It consists of a resistance monitoring device installed on all or a part of the line of the heating element to measure the resistance of the heating element passing through the cooling device, so that a narrow oven space can be efficiently used while using a relatively short length tunnel type heat treatment oven. The effect that this does not occur can be obtained.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic cross-sectional view showing a repeated, continuous heat treatment apparatus of the present invention, the configuration of which is largely tunnel-type heat treatment oven (1), cooling device (8), pulley (4) (5), resistance monitoring device (10) (11) (12). The tunnel heat treatment oven 1 is located on one side between two pulleys 4 and 5, and the cooling device 8 is located between the outlet 15 and the pulley 5 from the heat treatment oven 1, and the resistance The monitoring electrode 10 is installed at a position where the product is cooled. The heat generating element 13 to be heat-treated is released by the discharger (6) proceeds by the driving force of the two pulleys (4) (5) and the winder (7) and the heated tunnel-type heat treatment oven (1) and cooling device (8) ) Is repeated through the specified number of times. Therefore, when passing through the heated heat treatment oven (1), only linear motion is performed, and the cooling device (8) is sufficiently cooled before reaching the pulley (5) for reciprocating motion so that deformation occurs during rotation and bending motion in the pulley. I never do that.

The tunnel-type heat treatment oven 1 has an inlet 14 and an outlet 15 of the heating element as shown in FIG. 2 and a plurality of supporting rollers 2 for preventing sagging of the heater and the heating element uniformly arranged up and down. Has In addition, for the convenience of operation, such as during the initial setting was to install the lid 16 to open and close. The length of the oven may vary depending on the heating time of a single heat treatment, an appropriate ship speed, etc., and the longer the length, the more free the adjustment of the heat treatment heating time. The proper heating time of the one-time heat treatment is about 10 to 20 minutes in this case, if the oven length of 10m to 20m can have a line speed of about 1m / min. Since the length of the oven is long and heat loss occurs at the inlet 14 and the outlet 15, the oven is divided into several zones so that a heater and a temperature controller are separately installed to maintain the correct temperature in each portion. By connecting and installing the unit heat treatment oven manufactured in the form of FIG. 2 in series as shown in FIG. 1, the length of the heat treatment oven can be easily increased or decreased and the temperature of each zone can be precisely controlled.

In the heat treatment process of the autonomous temperature controlled polymer heating element, not only heating but also cooling process is very important, and it is necessary to have a constant cooling process. The cooling device 8 is provided with a cooling fan 9 in a sealed space of a certain form in order to have a constant cooling characteristics, so that the heating element 13 in the heated state passing through the cooling device is gradually cooled.

The pulley 3 has a simple structure as shown in FIG. 3, wherein the size of the grooves should be larger than the width of the heating element, the number of grooves depends on the number of heat treatment repetitions, and the spacing between the grooves is used for the resistance monitoring electrode. Space should be provided for each repetition of heat treatment.

The structure of the resistance monitoring electrode 10 is shown in FIG. 4, and two electrodes 17 are installed in the thickness direction of the product at the cooled position for each number of heat treatments and connected to the resistance meter 11. Each electrode 17 is in contact with the heating element 13 by a spring device, and must be fixed so as not to cause mechanical scratches or deformation on the heating element.

The computer 12 analyzes the resistance value measured by the resistance measuring device 11 for each heat treatment repetition number and shows the progress of the heat treatment process to the worker. The resistance value in the thickness direction measured here may vary depending on the contact area between the electrode and the heating element. The larger the contact area, the greater the accuracy. This value shows the property directly proportional to the resistance value and output of the finished product.

Therefore, the continuous heat treatment apparatus of the present invention can efficiently use a narrow oven space while using a relatively short length tunnel type heat treatment oven, and no deformation occurs, and the heating time of a single heat treatment is determined by the length and flux of the tunnel type oven. Therefore, the heating time can be adjusted by adjusting the flux and the number of heat treatment repetitions can be easily increased by increasing the number of grooves of the pulley.

In addition, since the number of times of repeated heat treatment increases, the resistance of the product tends to saturate to a constant value, thereby obtaining a more uniform product. Furthermore, in the heat treatment apparatus of the present invention, continuous resistance monitoring is possible. In the case of using the repetitive and continuous heat treatment apparatus of the present invention, an appropriate time for heating in one heat treatment is 10 minutes to 20 minutes. In such a short heat treatment, even if heat treatment is performed at a high temperature above the melting temperature, no large deformation occurs in the heating element. The heat treatment process has the advantage of being possible, in which case the resistance can be continuously monitored by physically contacting the electrode of the appropriate type with the cooled heating element.

The heat treatment operation sequence using the repeated and continuous heat treatment apparatus of the present invention is as follows. The first heating element bobbin, which has been compressed, is fixed to the discharger 6 and passed through two pulleys 4 and 5, a tunnel heat treatment oven 1, a cooling device 8, a resistance monitoring electrode 10, and the like. Connect with tiles. The heating element released from the feeder (6) is connected to the first groove of the left pulley (4), after one round trip, to the second groove, and after the last round trip to the last groove of the right pulley (5) and then to the winder (7). Coiled to the bobbin). When the heater 3 is activated and the heat treatment oven is heated to the desired setting temperature, the cooling device 8, two pulleys 4, 5, the winder 7, the resistance monitoring device 10, 11, 12 Turn on the light and start working. After the last reciprocation, check whether the monitoring resistance of the heat-treated product is within the desired standard value and adjust the oven temperature and speed so that the resistance value is within the desired standard value.

Embodiments proceeded with such a working method is as follows.

EXAMPLE

The length of the oven used was 15 m, the heat treatment temperature was 140 ° C., the line speed was 1 m / min, the number of heat treatment repetitions was 20 times, and the length of the cooling line was 5 m.

Therefore, the heating time of one heat treatment was 15 minutes, the cooling time in the cooling device was 5 minutes, and the total cooling time was more than 25 minutes. When the heat treatment was performed under such conditions, the decreasing tendency of the thickness direction resistance obtained by the resistance monitoring device was as shown in FIG. When the number of times of heat treatment was repeated more than 10 times, there was no significant decrease in additional resistance. When the heat treatment was repeated 20 times, a product having a very uniform resistance in the longitudinal direction of the product was obtained. Increasing the one-time heat treatment time increases the resistance reduction rate according to the number of repetitions and reduces the number of repetitive heat treatments required. When the heating time of the single heat treatment was adjusted between 10 minutes and 20 minutes, the structural change of the product hardly occurred.

Claims (7)

In the continuous heat treatment method of the autonomous temperature controlled polymer heating element, it is configured to repeat the heating and cooling several times for a relatively short time, the high temperature during the heat treatment of the autonomous temperature controlled polymer heating element is only linear movement in the heat treatment state, only in the cooled state A continuous continuous heat treatment method of an autonomous temperature controlled polymer heating element, characterized in that deformation is not generated in a product by rotating and bending. Two or more pulleys having a parallel axis of rotation separated from each other, a tunnel-type heat treatment oven located between the pulleys, a cooling device located between the outlet of the heat treatment oven and one of the pulleys, and a cooled autonomous temperature controlled polymer heating element. It consists of a resistance monitoring device installed at an arbitrary position on the line to measure the resistance. The heating and cooling process can be repeated several times, and the linear motion is only performed in the high temperature heating state, and the rotation and bending motion only in the cooled state. A repeating continuous heat treatment apparatus for an autonomous temperature controlled type polymer heating element. According to claim 2, wherein the tunnel-type heat treatment oven is a plurality of unit heat treatment oven is connected in series, the unit heat treatment oven has an inlet through which the heating element product can be introduced from the outside; An outlet through which the heat treated product can go out after heat treatment; A plurality of support rollers installed in the product path inside the oven to prevent the heated product from stretching during linear motion; Heaters regularly arranged above and below; Repeated continuous heat treatment apparatus of the autonomous temperature control type polymer heating element characterized in that it is provided with an open and close oven lid installed on the upper surface. 3. The pulley of claim 2, wherein the pulley is provided outside of the tunnel heat treatment oven and has a plurality of flat grooves around the product so that the product is continuously applied to a side groove to reciprocate the heat treatment oven and the cooling device several times. Repeating, continuous heat treatment apparatus of the autonomous temperature controlled polymer heating element, characterized in that configured to be. 3. The repeating and continuous heat treatment apparatus of an autonomous temperature controlled polymer heating element according to claim 2, wherein the cooling device has a sealed space and a cooling fan is installed. 3. The resistance monitoring apparatus according to claim 2, wherein the resistance monitoring device is installed at a cooled position of a repetitive and continuous heat treatment line, and has a pair of monitoring electrodes installed in a thickness direction of the product, and a resistance measuring device connected to the monitoring electrodes. And a computer that is connected to the resistance measurement facility and comprehensively analyzes the data, wherein the resistance monitoring device may be installed at every number of heat treatments or may be installed at only a part of the lines, and the monitoring electrode may be provided at a spring device having elasticity. Repeating, continuous heat treatment apparatus of the autonomous temperature controlled polymer heating element, characterized in that in contact with the surface of the product. 3. The repeated and continuous heat treatment apparatus of an autonomous temperature controlled polymer heating element according to claim 2, wherein the heating element is a heating element without an insulation jacket or a heating element with an insulation jacket.