KR100365810B1 - Drawing apparatus for manufacturing of thermoplastic polyester-based heat shrinkable tubes - Google Patents

Abstract

The present invention uses a polyethylene terephthalate (PET) material to stretch an unstretched tube to have a predetermined shrinkage in the process of manufacturing a thermoplastic polyester heat shrinkable tube used for insulation coating of an electrolytic capacitor or for packaging and coating batteries. The present invention relates to a drawing apparatus of a thermoplastic polyester heat-shrinkable tube, to which the present invention comprises preheating means (10) for preheating the unstretched tube (50) solidified by cooling in an unstretched state as predetermined hot water; A first feed roller 20 for compressing and feeding the preheated unstretched tube 50; Sizing means (30) for instantaneous contact with the heating medium while passing the unstretched tube (50) drawn out from the first feed roller (20) through a passage of a constant inner diameter and quenching by cooling water; A second feed roller which draws the tube 50 drawn in the width direction while being drawn out from the sizing means 30 and is drawn in the longitudinal direction by the speed of compressing and conveying the tube 50 while filling a predetermined amount of air therein. It is characteristic to make it as (40).

Description

Drawing apparatus for thermoplastic polyester-based heat shrinkable tubes

The present invention relates to an apparatus for stretching a thermoplastic polyester-based heat shrink tube that has a shrinkage rate that requires an unstretched tube in a process of manufacturing a heat shrink tube using a polyethylene terephthalate (PET) material.

In general, most of the tubes used for insulating coating of electrolytic capacitors or battery packaging have been made of polyvinyl chloride (hereinafter abbreviated as PVC) heat shrink tubes.

PVC is an amorphous polymer material having a glass transition temperature of about 80 ° C., and the melting point of the part having a crystalline structure (less than about 5%) is about 225 ° C.

However, before this temperature is reached, it is almost impossible to observe the melting point of PVC because pyrolysis starts to occur in PVC. Pure PVC releases chlorine gas when it starts to exceed 100 ℃ below the processing temperature.

On the other hand, PVC tubes are usually melted only when heated up to 230 ° C, while the gas generated during such processing is required to be promptly improved in terms of working environment, and during the extrusion process, the mold must be cleaned and restarted from time to time to perform defects. This large amount of production or reduced productivity may cause a significant increase in manufacturing costs, and in particular, the present situation has to be treated as industrial waste because recycling is impossible even in the event of a defect.

In addition, due to the limitations of PVC resin itself, it is very difficult to match the quality of high heat-resistant products, and when exposed to high energy such as ultraviolet light, it is activated and causes complex aging such as dehydrochloric acid, molecular cutting crosslinking, and oxidative decomposition In the case of a soft product, there is a problem in that the product is gradually cured by the migration of the plasticizer, and the hydrolysis phenomenon may proceed by reacting with the surrounding moisture.

In particular, due to the debate on the harmfulness of the human body, which originated in developed countries, various heavy metals have begun to be reported, causing gaseous carcinogenesis, and some toy products prohibit the use of DOP, which is mainly used in PVC. A step-down plan is under way.

Therefore, recently developed as an alternative material of such PVC is polyethylene terephthalate (PET), also called polyester, which is a polymer resin having an ester group (-O-CO-).

PET is fed to the extruded PET chip to the extruder by heating melt mixing (mixing) at 220 ~ 290 ° C to be extruded while quantitatively controlled by the extruder.

In addition, since PET has a glass transition temperature of around 75 ° C, the viscosity of PET melt has very low shear rate dependence, so it can be treated as Newtonian fluid. It must be raised so that it can be derived from the dice.

The semifinished product thus produced is drawn at a temperature above the glass transition temperature to obtain a PET shrink tube product.

However, PET can be manufactured by mixing processing or additives under special conditions with respect to the compositional relationship and chemical properties for forming as a tube, while maintaining the properties required during the actual manufacturing process, such as when manufacturing a PVC tube. It is very difficult to have an optimal shrinkage rate.

In particular, in order to make tubular tubes such as those used for insulating coating of electrolytic capacitors or for packaging and covering batteries, it is necessary to have the desired shrinkage while maintaining optimum viscosity during the manufacturing process. Although registered in Korean Patent No. 213512 (name: heat shrinkable tube) and Japanese Patent Application Laid-open No. Hei 5-104631, Japanese Patent Application Laid-open No. Hei 10-25351 and Japanese Patent Application Laid-open No. Only the conditions for the crystallinity, shrinkage rate, and component ratio of the product were suggested in the fabrication of the elongation tube. As described above, PET is required to satisfy the appropriate conditions because its physical properties are different from those of conventional PVC. Since the manufacturing method to have a heat shrinkage ratio of Practical production is almost impossible.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to use a heat shrink tube for insulation coating of an electrolytic capacitor or packaging and coating of a battery using PET resin which is harmless to the environment. The main purpose is to have a shrinkage rate.

1 is a structural diagram showing a drawing apparatus according to the present invention,

Figure 2 is an enlarged cross-sectional structural view of the sizing means of the present invention.

Explanation of symbols on the main parts of the drawings

10: preheating means 20: first feed roller

30: sizing means 31: pipe

32, 33, 34: chamber 35: induction hole

40: second feed roller 50: tube

In order to achieve the above object, the present invention includes a preheating means which is solidified by cooling in an unstretched state so that the unstretched tube is preheated while passing a predetermined hot water; A first feed roller which compresses and feeds the preheated unstretched tube; Sizing means for instantaneous contact with a high temperature heat medium while passing the unstretched tube drawn out from the first feed roller through a passage of a constant inner diameter and quenching the same; It is characterized in that it is provided as a second feed roller which is drawn out from the sizing means and is drawn in the longitudinal direction by the speed of compressing and conveying the tube while filling a predetermined amount of air inside the tube drawn in the width direction.

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

The use of low viscosity PET in the manufacture of heat-shrinkable tubes is unable to maintain the required tubular shape in the initial molten state.

Therefore, it is possible to stretch the resin in the molten state once it has been molded, so that it is solidified by quenching, and thus the unstretched tube is stretched.

As shown in FIG. 1, the preheating means 10 is configured to preheat the unstretched tube 50 in advance so that the unstretched tube 50 solidified by cooling can quickly obtain a change in physical properties due to high temperature.

As a configuration for this, the preheating means 10 is formed as a water tank 11 filled with a predetermined amount of water, wherein the temperature of the water in the water tank 11 is 60 ~ 98 ℃, the unstretched tube passing through the water tank 11 ( 50) is to move along the water surface so that the water level of the water filled in the tank 11 is preferably filled to a height slightly finer than the diameter of the unstretched tube (50).

The first feed roller 20 is configured to be conveyed at a constant speed while the unstretched tube 50 passing through the preheating means 10 no longer sags, so that a pair of rollers are provided facing each other up and down. Then, the unstretched tube 50 is conveyed while being compressed between the pair of rollers.

The sizing means 30 is configured as a tubular pipe 31. The pipe 31 has a shape such that the inner diameter is made constant so as to penetrate in the longitudinal direction as shown in FIG. The high temperature heat medium is introduced into the furnace, and the chamber 32 is formed at the other end thereof to allow the cooling water to flow into the outer circumferential surface thereof.

In particular, the outer circumferential surface of the pipe 31 is formed in the chamber 32, 33, 34 having a predetermined interval in three places in the longitudinal direction, and at this time, the high temperature heat medium is introduced into the chamber 32 of the tip side Into the chamber 33 of one side, the high temperature heat medium introduced into the front end side is discharged to the outside, and only the cooling water flows out into the chamber 34 formed at the end corresponding to the front end.

In addition, the chamber 32 on the tip end side communicates with the inner diameter part in a predetermined size, and an induction hole 35 for communicating with the heat medium discharge chamber 33 is formed at the end of the communication hole. In the chamber 34 formed at the end of the), the inlet and the outlet through which the coolant flows in and out are formed on surfaces corresponding to each other.

Therefore, the tube 50 passing through the inner diameter portion of the pipe 31 has a high temperature heat medium directly in contact with the outer circumferential surface at the front end portion of the pipe 31, but the cooling water does not directly contact the tube 50 at the other end portion. It is a configuration.

On the other hand, the second feed roller 40 is provided with a pair of rollers face up and down like the first feed roller 20 so that the tube drawn out from the pipe 31 through the sizing means 30 between the pair of rollers ( 50 is compressed and conveyed, and the tube 50 guided to the second feed roller 40 is supplied with a predetermined amount of air therein while the outer diameter of the tube 50 is expanded in the width direction. It is configured to be compressed and conveyed.

In particular, the tube 50 conveyed through the second conveying roller 40 is conveyed at a speed at which the tube 50 is wound on the winding roller.

Hereinafter, the operation of the present invention according to the above configuration will be described.

In general, the heat shrink tube 50 using the thermoplastic resin is produced by extrusion molding.

That is, PET heated to a high temperature is a molten state of low viscosity while being melted, and when it is quenched and solidified, the inside becomes hollow and has a tubular shape having a constant thickness.

The tube 50 in the unstretched state is preheated while passing through the preheating means 10 of the present invention and then conveyed at a constant speed while passing through the first feed roller 20, and the first feed roller 20. The unstretched tube 50 which is conveyed from is to be stretched while passing through the sizing means 30.

In other words, the unstretched tube 50 passing through the sizing means 30 is in contact with the hot steam at the tip of the pipe 31 while passing through the inner diameter of the pipe 31.

At this time, the tube 50 is spaced apart from the inner diameter surface of the pipe 31 while the outer diameter is slightly reduced by the high temperature heat medium flowing through the chamber 32 provided from the inner end to the outer end of the pipe 31. do.

The tube 50 which is rapidly heated while being in contact with the high temperature heat medium is heated to the temperature of the heat medium to a distance up to the induction hole 35 formed in communication with the chamber 33 side adjacent to the front end side chamber 32 of the pipe 31. The outer diameter is maintained in a compressed state by passing the induction hole 35 and the high temperature heat medium is led to the chamber 33 through the induction hole 35 and discharged to the outside, so that the tube 50 is induction hole 35. Only the position of the outer diameter is reduced, the outer diameter is in close contact with the inner diameter surface of the pipe 31 again.

When the tube 50 is guided to the rear end side of the pipe 31 in the state of contact between the surfaces as described above, the outer diameter of the tube 50 is changed to the inner diameter of the pipe 31 while being quenched by the coolant flowing into the chamber 34 at the rear end side. To be fixed.

After passing through the sizing means 30, the tube 50 is stretched in the width direction, and the tube 50 drawn out from the sizing means 30 is drawn out at a constant speed by the second feed roller 40. As a result, a predetermined amount is wound around the winding roller.

On the other hand, the inner diameter of the tube 50, which is transferred from the sizing means 30 to the second feed roller 40, is filled with 1.0-8.0 kg㎠ / ㎠ of air so that the outer diameter is forcibly expanded. 50 extends the tube 50 in the longitudinal direction while being transported by the winding speed in the winding roller.

Therefore, the present invention performs the stretching in the width direction by the sizing means 30, the stretching in the longitudinal direction by the winding speed of the take-up roller, and eventually the tube 50 wound on the take-up roller is required in the width direction and The shrinkage in the longitudinal direction is to produce a heat shrink tube 50 continuously.

The shrinkage in the width direction of the tube 50 drawn by such a sizing means 30 is about 40 to 60%, and the shrinkage in the longitudinal direction of the tube 50 drawn by the winding speed is 0 to 30%. Most preferred.

Although the heat shrink tube 50 is manufactured by using the PET resin having a low intrinsic viscosity by the above-described configuration and action, the heat shrinkage rate is the same as that of the heat shrink tube 50 manufactured using the PVC resin. When applied to an electrical device, the adhesion to the electrical device is increased so that the reliability of the product can be further improved.

For example, the thermoplastic polyester resin is dried in a dryer at a moisture content of 100 PPM or less, mixed with an appropriate amount of additives and pigments, and then put into a hopper, and extruded through a circular die while melting at an extruder at a cylinder temperature of 220 to 290 ° C. While the molten resin was quenched, an unstretched tube having a long axis of 16 mm and a short axis of 400 µm can be obtained.

When the unstretched tube is preheated to a temperature of 80 ° C and then stretched with a Ø19mm stretched tube using compressed air at a stretching temperature of 100 ° C, and immediately cooled to a cooling temperature of 18 ° C, the shrinkage in the width direction is 45% and the longitudinal shrinkage is 7%. You get a tube product that is%.

As such, changes in tube shrinkage, processing properties, and physical properties under various conditions of temperature conditions, that is, preheating temperature, stretching temperature, and cooling temperature according to the present invention, are as shown in Table 1.

At this time, the shrinkage rate was cut to 100mm in length and immersed in 98 ± 2 ℃ water for 30sec, then shrinkage rate (%) = ((product size before shrinking-product size after shrinking) / product size before shrinking It calculated by (x) * 100.

And after cutting each tube product produced through such a process, using a No. 8 needle in the center of the body of the coated product using a 500kgf / ㎠ force, and left in a 160 ℃ dry oven for 120 seconds to measure the heat resistance Table 1 You will get the same result.

In addition, when the heat-shrinkable tube products prepared as described above were cut and inserted into a Ø18 mm electrolytic capacitor and a battery, and then left in a dry oven at 280 ° C. for 8 seconds, the results obtained as shown in Table 1 can be obtained.

Table 1

As described above, the stretching apparatus of the heat-shrink tube 50 according to the present invention has a width in the width direction and a length direction in which the amount of heat required for stretching is high, and the temperature range is narrow and the PET resin has a characteristic of being rapidly drawn at a constant temperature. By having a shrinkage rate, there is a very useful effect that can be manufactured as a heat shrink tube 50 used for insulation coating of an electrolytic capacitor or packaging and coating of a battery.

Claims (5)

Preheating means (10) for preheating the unstretched tube (50), which is solidified by cooling in the unstretched state, while passing a predetermined hot water; A first feed roller 20 for compressing and feeding the preheated unstretched tube 50; Sizing means (30) for instantaneous contact with a high temperature heat medium while passing the unstretched tube (50) drawn out of the first feed roller (20) through a passage of a constant inner diameter and quenching by cooling water; A second feed roller which draws the tube 50 drawn in the width direction while being drawn out from the sizing means 30 and is drawn in the longitudinal direction by the speed of compressing and conveying the tube 50 while filling a predetermined amount of air therein. 40; A stretching apparatus of a thermoplastic polyester heat shrink tube provided as a. The stretching apparatus according to claim 1, wherein the preheating temperature in the preheating means (10) is 60 to 100 ° C. 2. The stretching apparatus of a thermoplastic polyester heat shrink tube according to claim 1, wherein the high temperature heat medium in said sizing means (30) is a temperature of about 95 to 110 캜. The apparatus of claim 1, wherein the cooling water flowing to the sizing means (30) is at a temperature of about 5 to 30 ° C. The method of claim 1, wherein the shrinkage in the width direction of the tube 50 drawn by the sizing means 30 and the second feed roller 40 is 30 to 60% and the longitudinal shrinkage is 0 to 30% thermoplastic polyester Drawing device for heat shrink tube.