[DESCRIPTION] [invention Title]

METHOD FOR PRODUCING INSULATOR FOR CONDENSER AND INSULATOR FOR CONDENSER PRODUCED THEREBY

[Technical Field]

The present invention relates to a method for producing an insulator that can be used as a dielectric and as an insulator for a condenser. More specifically, the present invention relates to a method for producing an insulator for a condenser having excellent electric properties as an insulating wax that is used for insulating a dielectric installed between the electrodes of a condenser and for sealing the condenser, and to a wax produced by the method.

[Background Art]

Condenser is a part used essentially for constituting various circuits of general electrical products, thus electrical reliability, heat stability, and the like are required largely.

In order to satisfy the needs for such electric properties polymer thin films, such as a paper,

polypropylene, or Teflon, various oils, such as a silicon oil, or a vacuum pump oil, and ceramics, such as mica, alumina, tantalum oxide, titanium oxide, barium titanate, or strontium titanate are used generally as an insulating material. In the case of using polymer thin films, an excellent condenser can be obtained due to small loss and deformation, however there is the disadvantage in that the shape becomes large. In the case of using ceramics, there is the advantage of small loss and deformation, however a condenser having high-capacity cannot be produced relative to the dielectric constant. Moreover, a ceramic condenser using a dielectric material is noticeably degraded due to insulation resistance (IR) by the applied electric field, thus there is the disadvantages of a short life and low reliability.

In the case of producing a condenser using a liquid- phase dielectric material, when a polar compound having conductivity or unsaturated compound is doped in the liquid, these substances become a core for degrading the oil thereby accelerating the oil degradation even more, thus there is the disadvantage of reducing the life of the condenser.

For example, Japanese Patent Laid-open Publication No. Showa 59-22715 discloses a technology for depositing zinc or aluminum on a polypropylene film, and forming an insulating layer such as a silicon oil thereon, because there is a

problem of decreasing a condenser capacity due to partial oxidation on the surface of metal electrodes made of, for example aluminum, zinc or the like. Korean Patent Publication No. 90-005206 suggests a method for forming a zinc deposition layer on one side of a solid made of a film or a thin sheet for a condenser, and vacuum depositing a substance selected from a dimethyl silicon oil, a silicon oil for vacuum pump, a fatty acid, a fatty acid salt, and a paraffin wax in a thickness of 7 to 500 A. Furthermore, Korean Utility Model Publication No. 95-0008078 discloses a composite-style condenser including an aluminum case, in which the aluminum case consisting of a core, a primary coil wound on the core as a driving condenser element, an insulating film between layers wound on the primary coil for insulation, a secondary coil wound on the insulating film as a start-up condenser element, and an insulating wax filled between the secondary coil and the aluminum case.

These condensers consistently require good temperature properties. Especially, uniform temperature properties under strict conditions are demanded depending on their use.

[Disclosure] [Technical Problem]

Therefore, the present invention has been made in

view of the above problems, and it is an object of the present invention to provide an insulator for a condenser in which an oil or wax used for a dielectric that meets the trend of miniaturization and high-capacity of a condenser is deformed and purified to fit its characteristics such that the insulator has good pour point, dielectric breakdown voltage, dielectric dissipation factor, total acid number, and the like that satisfy as a dielectric for a condenser, and also may prevent metal electrodes from oxidizing.

[Technical Solution]

In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a method for producing an insulator for a condenser comprising: preparing a paraffinic oil (A) by reforming a distillation-fractionated oil (C2o~C ₆ o) , obtained from distilling and fractioning a crude oil through constant temperature distillation, vacuum distillation or the like, via a hydrocracking process, separating and purifying the reformed oil using a thin-film separation apparatus under the pressure of 0.1 torr, at 200 ⁰ C to reform an iso-paraffin to a normal paraffin and separate thereof, and then purifying the separated normal paraffin

by adding an activated clay; preparing a micro crystal wax

(B) by removing an oil to less than 1% by weight from a solid wax separated and purified from the vacuum distillation residual oil or heavy flux oil via a methyl isobutyl ketone (MIBK) deoiling and purification process, and purifying the resulting substance with an activated clay; and mixing 70 to 80 parts by weight of the prepared paraffinic oil (A) and 30 to 20 parts by weight of the prepared micro crystal wax (B) , and treating the mixture with an activated clay.

In the mixing ratio of the paraffinic oil (A) and the micro crystal wax (B) , when the paraffinic oil (A) exceeds 80 parts by weight, there is an advantage in that the dielectric breakdown voltage may increase, but the pour point is dropped to 40 ⁰ C or lower, thus a problem occurs as a dielectric due to destruction in the oil insulation by degradation in use of the condenser. When the paraffinic oil (A) is used in the amount less than 70 parts by weight, the relative amount of the micro crystal wax (B) increases, thus problems occurs where the insulator becomes overly cured such that cracking is generated in the condenser and the metal electrodes are exposed thereby accelerating the oxidation, and an electrical short circuit may be generated. As described above, the present invention includes

preparing a paraffinic oil, preparing a micro crystal wax, mixing of the paraffinic oil and the micro crystal wax, and treating the mixture in the presence of an activated cay. The object of the present invention can be achieved by giving an effect on the life and the electrical stability of a condenser according to the mixing ratio of the purified paraffinic oil and micro crystal wax in the present invention, as well as by treating the mixed paraffinic oil and micro crystal wax with an activated clay.

The reaction temperature in the activated clay treatment after the mixing is 90 to 110 ⁰ C. When the treating temperature is less than 9O ⁰ C, a complete mixing is difficult due to the melting point of the micro crystal wax (B) , thus a heterogeneous insulator may be produced. When the treating temperature exceeds HO ⁰ C, the paraffinic oil evaporates thereby causing the cracks due to a higher content of the micro crystal wax. Moreover, the color change and lowering of electric properties in the mixture product by degradation may be generated. Therefore, it is preferable to treat the mixture of the paraffinic oil and micro crystal wax in the above range of temperature.

The amount of activated clay used for treating the mixture of paraffinic oil and micro crystal wax is preferably about 2 to 3 parts by weight based on 100 parts

by weight of the insulator mixture. When the activated clay is added less than 2 parts by weight, the pour point after the production lowers extremely, thus the insulator melts due to the heat generated during the use of the condenser. As a result, the insulator may flow out, or the dielectric layer becomes overly thinned thereby generating problems of lowering dielectric performances. When the activated clay is added more than 3 parts by weight based on 100 parts by weight of the insulator, the activated clay does not have an effect on improving the insulator performance after the treatment. Instead, the purification speed is reduced, and the cost is increased.

Furthermore, it is more preferable that the activated clay treatment is carried out twice by dividing the total amount of the activated clay in the range of 3 parts by weight .

[Best Mode]

The present invention will be better understood from the following examples. These examples are not to be construed as limiting the scope of the invention. Example 1

A paraffinic oil (A) was prepared by reforming a distillation-fractionated oil (C20-C6 ₀ ) _r obtained from

distilling and fractioning a crude oil through constant temperature distillation, vacuum distillation or the like, via a hydrocracking process, separating and purifying the reformed oil using a thin-film separation apparatus under the pressure of 0.1 torr, at 200 ⁰ C to reform an iso- paraffin to a normal paraffin and separate thereof, and then purifying the separated normal paraffin by adding an activated clay. Moreover, a micro crystal wax (B) was prepared by removing an oil to less than 1% by weight from a solid wax separated and purified from the vacuum distillation residual oil or heavy flux oil via a methyl isobutyl ketone (MIBK) deoiling and purification process, and purifying the resulting substance with an activated clay. Thus prepared paraffinic oil (A) and micro crystal wax (B) were mixed in a formulation as listed in the following Table 1. Then, 3 parts by weight of an activated clay based on the total weight of the mixture was added and stirred at the speed of 300 rpm for 30 minutes while maintaining the reaction temperature at 100 °C. Subsequently, the activated clay was removed by filtration in vacuo. The pour point

(based on KS M 2016) , dielectric breakdown voltage (based on

KS C IEC 60156) , dielectric dissipation factor (based on KS

C 2101), total acid number (based on KS M ISO 6618), and moisture (based on KS C 2101) of the produced mixture were measured, and the results are also listed in Table 1.

When the results in Table 1 obtained by carrying out Example 1 were analyzed, in the case where 60 parts by weight of the paraffinic oil (A) and 40 parts by weight of the micro crystal wax (B) were used, excellent results exhibited in the dielectric dissipation factor and total acid number. However, it was confirmed that cracks generated at normal temperature, and application to a condenser was difficult due to decrease of the dielectric breakdown voltage to 60 KV or lower. In the case where 90 parts by weight of the

paraffinic oil (A) and 10 parts by weight of the micro crystal wax (B) were used, excellent results exhibited in the dielectric dissipation factor, total acid number, and dielectric breakdown voltage as with the other results. However, the pour point of the produced insulator is 4O ⁰ C or lower. Thus, when applying the insulator to a condenser, degradation in the condenser by the heat may easily be generated due to the low melting point according to its use. Further, since insulation of an oil is degraded early, reason for generating problems as a role in dielectric may be provided.

Therefore, it was confirmed that 70 to 80 parts by weight of the paraffinic oil (A) and 30 to 20 parts by weight of the micro crystal wax (B) are preferred for the mixing ratio of the paraffinic oil (A) and the micro crystal wax (B) according to the results of Table 1. Example 2

70 parts by weight of the paraffinic oil (A) and 30 parts by weight of the micro crystal wax (B) that show the best results in Table 1 were charged in a reactor and stirred at the speed of 300 rpm while heating to 9O ⁰ C. After completion of mixing, 1 part by weight of the activated clay was added and further stirred for 30 minutes. Then, the activated clay was removed by filtration in vacuo. The pour point (based on KS M 2016) , dielectric breakdown voltage

(based on KS C IEC 60156) , dielectric dissipation factor (based on KS C 2101) , and total acid number (based on KS M ISO 6618) of the produced mixture were measured, and the results are listed in Table 2. Example 3

The experiment was carried out in the same manner as in Example 2, except that 2 parts by weight of the activated clay was added, and the reaction temperature was set at 110 ⁰ C. The pour point (based on KS M 2016), dielectric breakdown voltage (based on KS C IEC 60156) , dielectric dissipation factor (based on KS C 2101) , and total acid number (based on KS M ISO 6618) of the produced mixture were measured, and the results are also listed in Table 2. Example 4 The experiment was carried out in the same manner as in Example 2, except that 3 parts by weight of the activated clay was added, and the reaction temperature was set at 100°C. The pour point (based on KS M 2016), dielectric breakdown voltage (based on KS C IEC 60156) , dielectric dissipation factor (based on KS C 2101) , and total acid number (based on KS M ISO 6618) of the produced mixture were measured, and the results are also listed in Table 2. Example 5 The experiment was carried out in the same manner as in Example 2, except that 2 parts by weight of the activated

clay was added, stirred for 30 minutes, and the activated clay was removed by filtration in vacuo. Then, 1 part by weight of the activated clay was added again, further stirred for 30 minutes, and the activated clay was removed by filtration in vacuo. The pour point (based on KS M 2016), dielectric breakdown voltage (based on KS C IEC 60156) , dielectric dissipation factor (based on KS C 2101) , and total acid number (based on KS M ISO 6618) of the produced mixture were measured, and the results are listed in Table 2.

Comparative Example 1

A paraffinic oil (A) was prepared by reforming a distillation-fractionated oil (C20-C ₆₀ ) _t obtained from distilling and fractioning a crude oil through constant temperature distillation, vacuum distillation or the like, via a hydrocracking process, separating and purifying the reformed oil using a thin-film separation apparatus under the pressure of 0.1 torr, at 200 ⁰ C to reform an iso- paraffin to a normal paraffin and separate thereof, and then purifying the separated normal paraffin by adding an activated clay. 70 parts by weight of the prepared paraffinic oil (A) was charged to a reactor, and 1 part by weight of activated clay was added thereto. The mixture was stirred at the speed of 300 rpm for 30 minutes while maintaining the reaction temperature at 100 ⁰ C. Then, the

activated clay was removed by filtration in vacuo to prepare 70 parts by weight of the purified paraffinic oil (A) . Separately, a micro crystal wax (B) was prepared by removing the oil to less than 1% by weight from the solid wax separated and purified from the vacuum distillation residual oil or heavy flux oil by a methyl isobutyl ketone (MIBK) deoiling and purification process, and purifying the resulting substance with activated clay. 30 parts by weight of the prepared micro crystal wax (B) was charged to a reactor, and 1 part by weight of activated clay was added thereto. The mixture was stirred at the speed of 300 rpm for 30 minutes while maintaining the reaction temperature at 100 ⁰ C. Then, the activated clay was removed by filtration in vacuo. Thus obtained micro crystal wax (B) was mixed with the paraffinic oil (A) . The pour point (based on KS M 2016) , dielectric breakdown voltage (based on KS C IEC 60156) , dielectric dissipation factor (based on KS C 2101) , and total acid number (based on KS M ISO 6618) of the produced mixture were measured, and the results are listed in Table 2.

Comparative Example 2

The experiment was carried out in the same manner as in Comparative Example 1, except that 2 parts by weight of activated clay was added, respectively. The pour point (based on KS M 2016) , dielectric breakdown voltage (based on

KS C IEC 60156) , dielectric dissipation factor (based on KS C 2101), and total acid number (based on KS M ISO 6618) of the produced mixture were measured, and the results are also listed in Table 2.

Comparative Example 3

The experiment was carried out in the same manner as in Comparative Example 1, except that 3 parts by weight of activated clay was added, respectively. The pour point (based on KS M 2016) , dielectric breakdown voltage (based on KS C IEC 60156) , dielectric dissipation factor (based on KS C 2101), and total acid number (based on KS M ISO 6618) of the produced mixture were measured, and the results are also listed in Table 2.

Table 2

As shown in Table 2, when Examples 2 to 5, which treated a mixture state of the paraffinic oil (A) and the micro crystal wax (B) with an activated clay, and Comparative Examples 1 to 3, which treated the paraffinic oil (A) and the

micro crystal wax (B) with activated clay separately, were compared, it was confirmed that the pour point in the result of Examples 2 to 5 exhibited higher temperature than Comparative Examples 1 to 3 that used the same amount of the activated clay.

Moreover, in the case of Example 2 the mixture was prepared in the same manner as in Examples 3 to 5, except that there was a difference in the amount of activated clay where 1 part by weight based on 100 parts by weight of the insulator was added. As a result, the pour point was 40°C or lower which is very low as in the results of Comparative Examples. Thus, the durability in the condenser is decreased due to easy degradation when applied to a condenser. Therefore, it was confirmed that the durability of the condenser can be increased when an insulator produced by the methods of Examples 3 to 5, in which 2 parts by weight or more of the activated clay is added based on 100 parts by weight of the insulator, is applied to a condenser.

[industrial Applicability]

As seen from the above, the insulator for a condenser according to the present invention has excellent dielectric breakdown voltage and dielectric dissipation factor while maintaining high pour point, and has low oxidation in the

metal film. Therefore, it is confirmed that the present invention is useful for improving durability of a condenser.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.