LEE GUN-JOO (KR)
LEE JOON-HEE (KR)
SEO DONG-JIN (KR)
LEE GUN-JOO (KR)
LEE JOON-HEE (KR)
| US4522745A | 1985-06-11 | |||
| US6228922B1 | 2001-05-08 | |||
| US5674969A | 1997-10-07 |
| A heat-resistant composition for an insulating wire, comprising a poly(diphenylether benzobisimidazole) polymer. |
| The heat-resistant composition for an insulating wire according to claim 1, wherein the poly(diphenylether benzobisimidazole) polymer has a repeating unit as given by the following Chemistry Figure: where R 1 , R 2 , R m and R n are respectively, functional groups selected from the group consisting of hydrogen, an alkyl group with 1 to 4 carbons, vinyl group, acryl group, methacrylic group and hydroxyl group, each of said R 1 , R 2 , R m and R n being identical to or different from one another, said R m and R n being independently ortho - or meta - to the ether oxygen atom. |
| The heat-resistant composition for an insulating wire according to claim 2, wherein R 1 , R 2 , R m and R n are hydrogen atoms. |
| The heat-resistant composition for an insulating wire according to claim 1, wherein the poly(diphenylether benzobisimidazole) polymer has a weight-average molecular weight of 10,000 to 100,000. |
| A varnish for electrical wire coating, comprising a solid containing a poly(diphenylether benzobisimidazole) polymer and a solvent, wherein the solid has a concentration of 5 to 40 weight%. |
| The varnish for electrical wire coating according to claim 5, wherein the poly(diphenylether benzobisimidazole) polymer has a repeating unit as given by the following Chemistry Figure: where R 1 , R 2 , R m and R n are respectively, functional groups selected from the group consisting of hydrogen, an alkyl group with 1 to 4 carbons, vinyl group, acryl group, methacrylic group and hydroxyl group, each of said R 1 , R 2 , R m and R n being identical to or different from one another, said R m and R n being independently ortho - or meta - to the ether oxygen atom. |
| The varnish for electrical wire coating according to claim 6, wherein R 1 , R 2 , R m and R n are hydrogen atoms. |
| The varnish for electrical wire coating according to claim 5, wherein the poly(diphenylether benzobisimidazole) polymer has a weight-average molecular weight of 10,000 to 100,000. |
| The varnish for electrical wire coating according to claim 5, wherein the varnish further includes 0.5 to 10 parts by weight of at least one additive selected from the group consisting of a radical polymerization initiator, a copper antioxidant, a thickener, an antifoaming agent, a surface tension depressant and a surfactant, based on 100 parts by weight of the poly(diphenylether benzobisimidazole) polymer. |
| The varnish for electrical wire coating according to claim 5, wherein the solvent is selected from the group consisting of dimethylacetamide (DMA), dimethylformamide (DMF) and N -methylpyrrolidone (NMP). |
| A heat-resistant insulating electrical wire, comprising: a conductor; and an insulation layer surrounding the conductor, wherein the insulation layer is made of a poly(diphenylether benzobisimidazole) polymer. |
| The heat-resistant insulating electrical wire according to claim 11, wherein the poly(diphenylether benzobisimidazole) polymer has a repeating unit as given by the following Chemistry Figure: where R 1 , R 2 , R m and R n are respectively, functional groups selected from the group consisting of hydrogen, an alkyl group with 1 to 4 carbons, vinyl group, acryl group, methacrylic group and hydroxyl group, each of said R 1 , R 2 , R m and R n being identical to or different from one another, said R m and R n being independently ortho - or meta - to the ether oxygen atom. |
| The heat-resistant insulating electrical wire according to claim 12, wherein R 1 , R 2 , R m and R n are hydrogen atoms. |
| The heat-resistant insulating electrical wire according to claim 11, wherein the poly(diphenylether benzobisimidazole) polymer has a weight-average molecular weight of 10,000 to 100,000. |
| The heat-resistant insulating electrical wire according to claim 11, wherein the insulation layer further includes 0.5 to 10 parts by weight of at least one additive selected from the group consisting of a radical polymerization initiator, a copper antioxidant, a thickener, an antifoaming agent, a surface tension depressant and a surfactant, based on 100 parts by weight of the poly(diphenylether benzobisimidazole) polymer. |
The present invention relates to a resin composition for an insulation layer of a highly heat-resistant insulating electrical wire, a varnish for electrical wire coating using the composition, and a highly heat-resistant insulating electric wire using the composition. More particularly, the present invention relates to an insulating wire useable at a temperature over 250℃.
As electric or electronic devices become smaller and denser, wires used for parts of electric devices should meet more complicated requirements. Heat-resistant wires traditionally used for various electric products generating much heat should also enhance their heat-resistant properties to cope with the reinforced safety. As examples of these wires, there are magnetic coils for electric devices, highly heat-resistant coils for motors, particularly wires for hybrid electric vehicles (HEV), and wires for airplane equipment, naval equipments, communication equipment in an army and electric/electronic harness, and so on. Such wires should meet strict criteria in electric, mechanical and chemical performances. In detail, such wires should have a thin insulation coating for an ultralight design, and they should be usable even in severe conditions such as high temperature.
In order to support such high heat-resistance and chemical stability, an insulation layer mainly composed of fluoric resin has been used. Also, polyesterimide, polyimide and polyamideimide resins have been widely used.
However, a fluoric resin such as tetrafluoroethylene contains fluorine that is a halogen element. Such a fluoric resin could be allowed for narrower fields in the future since environmental restriction and safety requirements are reinforced. Meanwhile, polyesterimide, polyimide and polyamideimide were useable at about 180℃, 200℃ and 220℃, respectively, so these resins may not give heat-resistance to a desired level.
In this reason, there has been many studies on highly heat-resistant insulating cables stably useable at a temperature over 250℃, but a satisfactory result is not yet found.
The present invention is designed to solve the problems of the prior art, and therefore it is an object of the present invention to provide a resin composition and a varnish for an insulation coating of a highly heat-resistant insulating electrical wire useable at a temperature over 250℃ without including halogen and ensuring excellent abrasion resistance, and an insulating wire using the same.
In order to accomplish the above object, the present invention provides a heat-resistant composition for an insulating wire, which includes a poly(diphenylether benzobisimidazole) polymer. Also, the present invention provides a varnish for electrical wire coating, which uses the above heat-resistant composition. The varnish according to the present invention includes a solid containing a poly(diphenylether benzobisimidazole) polymer and a solvent, and the solid has a concentration of 5 to 40 weight%.
In the present invention, there is also provided a heat-resistant insulating electrical wire, which includes a conductor, and an insulation layer surrounding the conductor, wherein the insulation layer is made of a poly(diphenylether benzobisimidazole) polymer.
The poly(diphenylether benzobisimidazole) insulating wire according to the present invention has high heat-resistance over 250℃ and excellent abrasion resistance, so it is suitable as an insulation layer of wires needing high heat-resistance such as wires for motors and alternators.
An insulation layer of a highly heat-resistant insulating electrical wire according to the present invention includes poly(diphenylether benzobisimidazole) polymer (hereinafter, referred to as "PDPEBI"). The PDPEBI polymer of the present invention includes a benzobisimidazole ring and two para -phenylene units connected thereto in the repeating unit, in which an ether oxygen is interposed between the two para -phenylene units. The following chemistry figure 1 shows one example of the PDPEBI polymer according to the present invention.
ChemistryFigure 1
The PDPEBI of the present invention may be produced in various ways, and its production is not limited to a specific method. As an example, the following chemistry figure 2 may be used. In this method, a substituted or non-substituted tetraaminobenzene monomer is reacted with a substituted or non-substituted dicarboxyldiphenylether monomer. The PDPEBI polymer of the present invention may be obtained through a condensation polymerization between the two monomers.
ChemistryFigure 2
In the chemistry figure 2, R 1 , R 2 , R m and R n are respectively, functional groups selected from the group consisting of hydrogen, an alkyl group with 1 to 4 carbons, vinyl group, acryl group, methacrylic group and hydroxyl group, and each of the R 1 , R 2 , R m and R n is identical to or different from another. In the dicarboxyldiphenylamide molecule, the R m and R n may be independently ortho - or meta - to the ether oxygen atom.
The PDPEBI polymer of the present invention preferably has a weight-average molecular weight of 10,000 to 100,000. If the PDPEBI polymer has a molecular weight within the above range, the viscosity characteristic is desirably good. However, if the molecular weight of the PDPEBI polymer is less than 10,000, viscosity is too low to ensure a good coating workability since the coating agent flows down during the coating work. On the other hand, if the molecular weight exceeds 100,000, viscosity becomes excessive, so that too much coating agent sticks to the wire during the coating work.
In the synthetic example shown in the chemistry figure 2, the water generated needs to be eliminated by adding a dehydrating agent for the condensation polymerization. For this, the dehydrating agent is preferably selected from a dehydrating agent having phosphorus pentoxide (P 2 O 5 ) and substituted sulfonic methyl (CX 3 SO 3 H) (where X is oxygen or fluorine), a polyphosphoric acid (PPA) dehydrating agent, and a mixed dehydrating agent having both phosphoric acid and phosphorus pentoxide.
The PDPEBI resin of the present invention, obtained as mentioned above, is applied onto a conductor for a wire in a varnish form and then baked to configure an insulation layer of a highly heat-resistant insulating electrical wire. PDPEBI is dissolved in a suitable solvent for coating and baking, thereby forming a varnish. At this time, the solvent for varnish is preferably a basic solvent such as dimethylacetamide (DMA), dimethylformamide (DMF) and N -methylpyrrolidone (NMP). The PDPEBI solid in the varnish may have a concentration of 1 to 80 weight%, more preferably 5 to 40 weight%. If the PDPEBI solid in the varnish has a concentration less than 5 weight%, the amount of PDPEBI used for constituting the insulating resin layer is insufficient, which may result in a poor heat-resistance or abrasion resistance or a use of an excessive amount of solvent. Meanwhile, if the solid has a concentration exceeding 40 weight%, the varnish has an excessive viscosity, which disturbs easy coating or baking.
The PDPEBI varnish according to the present invention may further include additives suitably selected depending on usages, in addition to PDPEBI polymer and solvent. Such additives may be a radical polymerization initiator that is added when the degree of polymerization of the PDPEBI polymer is low, a copper antioxidant, a thickener, an antifoaming agent, a surface tension depressant, a surfactant and so on. Such additives preferably have a content of 0.5 to 10 parts by weight, based on 100 parts by weight of PDPEBI resin in the solid.
The PDPEBI insulating wire according to the present invention includes a conductor layer made of conductive material such as copper and a PDPEBI insulation layer surround the conductor layer. In addition to the conductor layer and the insulation layer, the wire may further include elements commonly used for insulation wires such as other coating layers, sheath layers and braided layers. In case wires are used in special fields such as aviation or army, suitably components may be additionally provided to the wire suitably for its usage.
Hereinafter, various preferred examples of the present invention will be described in detail for better understandings. However, the examples of the present invention may be modified in various ways, and they should not be interpreted as limiting the scope of the invention. The examples of the present invention are just for better understandings of the invention to persons having ordinary skill in the art.
In order to evaluate the performance of an insulating wire having the PDPEBI insulation layer according to the present invention, insulating resin compositions were prepared according to the following examples and comparative examples, and they were applied to copper wires to make test pieces for insulation wires having the PDPEBI insulation layer.
Example 1
In order to produce PDPEBI of this example, 50g of polyphosphoric acid was put into 10 mmol of tetraaminobenzene and then heated at 120℃ for 30 minutes. After that, 10 mmol of dicarboxyldiphenylether was added thereto and polymerized at 170℃ for 6 hours, thereby preparing PDPEBI shown in the chemistry figure 1. This PDPEBI was dissolved in an NMP solvent to have a concentration of 15 weight%, thereby affording a varnish for forming an insulation layer. The varnish was applied to a naked copper wire with a diameter of 1.000 mm and then baked in a common way, thereby manufacturing an insulating wire.
Example 2
70:30 parts by weight of N-methylpyrrolidone and xylene was used as a solvent in a reactor with a reflux apparatus to react 4,4'-diphenylmethane diisocyanate (MDI) and trimellitic anhydride (TMA) at a 1:1.04 mole ratio, thereby obtaining a polyamideimide varnish.
The prepared polyamideimide varnish was applied as a first insulation layer to have a thickness of 5 micrometers, and PDPEBI was applied on the first insulation layer as a second insulation layer. Other processes are identical to the above example 1.
Example 3
Example 3 is substantially identical to the example 1, except that the polyamideimide varnish prepared in the example 2 was applied as a first insulation layer to have a thickness of 15 micrometers, and PDPEBI was applied on the first insulation layer as a second insulation layer.
Comparative Example 1
The polyamideimide varnish prepared in the example 2 was applied as an insulation layer on a naked copper wire with a diameter of 1.4 mm and then baked in a common way to make an insulating wire.
Comparative Example 2
A polyesterimide (Dupont, THEIC E 3533) varnish was used as a first insulation layer on a naked copper wire with a diameter of 1.4 mm, and the polyamideimide varnish prepared in the example 2 was used as a second insulation layer. After that, they were baked in a common way to make an insulating wire.
Comparative Example 3
Polyester (Altana DEATHERM T 810) was used as an insulation layer on a naked copper wire with a diameter of 1.5 mm and then baked in a common way to make an insulating wire.
Properties of the insulating wires prepared according to the examples and the comparative examples such as insulation breakdown strength, softening-resistant temperature, thermal shock resistance and appearance were evaluated as follows.
Appearance : Appearances of the wires were observed by the naked eyes.
Pinhole : Pinhole was measured according to regulations of KS C 3006 Standards.
Film flexibility : Film flexibility was measured according to regulations of KS C 3006 Standards.
Insulation breakdown strength : Insulation breakdown strength of the wires was measured according to regulations of KS C 3005 Standards. The evaluation result is considered as good if insulation breakdown strength is 10 or above, but the result is considered as bad if insulation breakdown strength is less than 10.
High temperature insulation breakdown strength : Insulation breakdown strength test was conducted after 250℃ x 168h thermal treatment. The test result is considered as good if high temperature insulation breakdown strength is 8 or above, but the result is considered as bad if high temperature insulation breakdown strength is less than 8.
Softening-resistant temperature : Softening-resistant temperature was measured according to regulations of KS C 3006 Standards. The evaluation result is considered as good if softening-resistant temperature is 420℃ or above, but the result is considered as bad if softening-resistant temperature is lower than 420℃.
Thermal shock resistance : Thermal shock resistance of the wires was measured according to regulations of KS C 3006 Standards.
The evaluation results for properties of the insulating wires prepared according to the examples and the comparative examples are shown in the following table 1.
Table 1
The insulating wires having the PDPEBI insulation layer according to the examples of the present invention were equal to the wires of the comparative examples in aspect of appearance and thermal shock resistance. However, the wires according to the examples of the present invention were greatly improved rather than the wires of the comparative examples in aspect of heat resistance that may be defined by softening-resistant temperature and high temperature insulation breakdown strength.
The present invention has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.