KR100730836B1 - Polyimide resin for using insulator of insulated wire and insulated wire - Google Patents

Abstract

Provided are a polyimide-based resin for the insulator of an insulating electric wire, and an insulating electric wire containing the polyimide-based resin which is very excellent in thermal stability, insulation, chemical resistance and flame retardancy. The polyimide-based resin is any one selected from the group consisting of a polyetherimide resin represented by the formula(1), a copolymer resin of siloxane and polyetherimide represented by the formula(2), and a sulfonate polyetherimide resin represented by the formula(3). The insulating electric wire comprises a conductor; and an insulator which surrounds the conductor and is prepared by molding the polyimide-based resin by extrusion molding.

Description

Polyimide resin for using insulator of insulated wire and insulated wire}

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to.

1 is a cross-sectional view of an embodiment of an insulated wire according to the present invention.

2 is a cross-sectional view of another embodiment of an insulated wire according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10. Insulated wire 11. Conductor 12. Insulator

20. Insulated wire 21. Conductor 22. First insulating layer

23. Second Insulation Layer 24. Insulator

The present invention relates to an insulator polyimide-based resin and an insulated wire manufactured using the same, and more particularly, good flowability and precise molding, and excellent insulator, flame retardancy, etc. It relates to a resin and an insulated wire produced using the same.

In general, polyethylene resins having relatively high electrical insulation as an insulator material for equipment wires or control and signal wires for special applications have been used with very thin extrusion coating. However, when a thin insulator is required, the insulator containing polyethylene resin is difficult to be extruded to a uniform thickness and has a disadvantage in that it is not adhered to other insulator materials of the lower layer. In addition, since the polyethylene resin is basically a low melting temperature and poor heat resistance at high temperatures, in order to be applied to an electric wire having a temperature grade of 150 ° C or higher, the polyethylene resin must be crosslinked through a method such as chemical crosslinking or irradiation crosslinking to improve heat resistance.

Accordingly, XLPE (cross-linking polyethylene) obtained by crosslinking the polyethylene resin has a heat resistance that satisfies both the conductor temperature of 250 deg. C generated by a short circuit current and the conductor temperature of 90 deg. After long-term exposure to temperatures up to 300 ° C, XLPE undergoes thermal deformation or carbonization. The XLPE is manufactured to improve the poor heat resistance of the polyethylene resin, but there is a limit to retain high heat resistance properties, and thus requires an insulation material to which a special antioxidant is applied. In addition, XLPE, which requires an additional process such as a crosslinking process, has a disadvantage in that productivity is lowered and manufacturing costs are additionally consumed. In addition, in order to impart flame retardancy to XLPE, XLPE has a disadvantage in that it must contain a flame retardant which is a hazardous substance, and an oxygen index of XLPE is usually 18% or less, and thus has a low flash point and inferior flame retardancy.

In general, resins having high crystallinity show a large difference in dimensional stability after extrusion processing depending on cooling conditions. For example, high-density polyethylene resins exhibit a phenomenon in which the stress during extrusion is severed and severely contracted at a high temperature during the cooling step. Therefore, insulated wires requiring high dimensional stability and very low shrinkage rate have limitations in using resins having high crystallinity.

In addition, when a polyimide tape is used in an electric wire, an insulator may contain the ethylene copolymer containing a polar group in order to improve the adhesive force with a polyimide insulating tape. However, resins such as ethylene copolymers having a low melting temperature and an amorphous ethylene copolymer are severely deformed when external force or load is applied at a high temperature even when crosslinked, resulting in a sharp drop in insulation performance and failure to satisfy required electrical properties. In addition, although a specific chemical agent is used to change the surface properties of the polyimide tape to induce adhesion with polyethylene, methods such as surface modification of the tape show a limitation in that the process is complicated and thus it is difficult to secure productivity and quality.

Therefore, efforts have been made to solve the above-mentioned problems in the related field, and are devised under this technical background.

The technical problem to be achieved by the present invention is that the above-mentioned problems, in particular, low heat resistance, flame retardancy and dimensional stability of polyethylene resin, high shrinkage, weak adhesion to polyimide tape, and additional manufacturing costs for manufacturing XLPE In order to solve the problem, there is an object of the present invention to provide an insulator polyimide-based resin for insulators and insulated wires manufactured using the same.

In order to achieve the above technical problem, the polyimide resin for insulator of the insulated wire provided by the present invention is a polyetherimide resin represented by the following formula (1), a copolymerized resin of siloxane and polyetherimide represented by the following formula (2), and It is a polyimide resin, which is any one selected from the group consisting of sulfonate polyetherimide resins represented by the formula (3).

In addition, the present invention is a conductor; And an insulator surrounding the conductor, wherein the insulator is a polyetherimide resin represented by Formula 1, a copolymerized resin of siloxane and polyetherimide represented by Formula 2, and represented by Formula 3 The present invention provides an insulated wire comprising a polyimide-based resin, which is any one selected from the group consisting of sulfonate polyetherimide resins, and a melt extrusion method.

Hereinafter, the present invention will be described in detail.

The present inventors conducted a study to satisfy the characteristics required for the outermost layer insulation of the control and signal wire having a heat resistance rating of 150 ℃ as an insulating material, the following polyimide (polyimide) resin was used as the insulating material.

The polyimide resin of the present invention can be melt-extruded alone, has characteristics of Newtonian fluid at low shear rate, exhibits high viscosity, and shows excellent thermal stability, so that a thin product can be sufficiently precise. Can be molded. In addition, polyimide-based resins can be extruded at various screw speeds, temperatures and pressures, and can be extruded in large quantities due to their inherent stability and variety of usability. The requirements of the properties can be easily met. In addition, the polyimide resin exhibits excellent properties such as heat resistance, flame retardancy, chemical resistance, electrical insulation, and the like, and the polyimide resin used in the present invention has the following characteristics.

Resin represented by the formula (1) is a polyetherimide (polyether-imide) using BABPA (bisphenol A) and MPDA (Meta Phenylene Diamine) as a monomer. Resin represented by the formula (2) is a copolymer of siloxane and polyetherimide. Resin represented by the formula (3) is a polyetherimide terpolymer resin such as sulfonated polyether-imide.

The polyetherimide-based resins represented by Chemical Formulas 1 to 3, respectively, are amorphous and have a stable physical property in the temperature range because the heat deformation temperature exceeds 200 ° C., and have long-term heat resistance and maintain strength and elastic modulus even at high temperatures. . In addition, the polyetherimide-based resin has a good fluidity, can be molded precisely even with a thin product, and has excellent dimensional stability. In addition, the polyetherimide resin exhibits very high flame retardancy even if it does not contain an additive and is recognized as UL-94V-0, and has a high flash point. In addition, the polyetherimide resin has the highest chemical resistance among amorphous resins, and has properties such as low combustion propagation rate, high oxygen index, excellent flame retardancy, and low smoke property through a radial panel test. It is a halogen-free material, and has excellent flexibility, flame retardancy, and chemical resistance. In addition, since the polyetherimide resin exhibits low smoke resistance, low corrosion resistance, and radiation resistance, the polyetherimide resin may be used in various ways as an insulation and sheath material for electric wires.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a cross-sectional view of an embodiment of an insulated wire according to the present invention.

As can be seen in Figure 1, typically the insulated wire 10 is composed of a conductor 11 and the insulator 12 surrounding it, wherein the insulator 12 is a polyetherimide resin represented by the formula (1), the formula It includes polyimide-based resin which is any one selected from copolymerized resin of siloxane represented by 2 and polyetherimide, sulfonate polyetherimide resin represented by the formula (3) and the like.

2 is a cross-sectional view of another embodiment of an insulated wire according to the present invention.

As shown in FIG. 2, the insulated wire 20 includes a conductor 21, a first insulating layer 22 surrounding the conductor 21, a second insulating layer 23 surrounding the first insulating layer 23, and an insulator 24 surrounding the conductor 21. It consists of). In this case, the first insulating layer 22 and the second insulating layer 23 may be mica tape, polyimide tape, silicone coated mica tape, polyester tape, teflon tape, silicone tape, asbestos tape, Butyl tape or the like can be used.

Although not specifically illustrated in the drawings, an interlayer insulating layer including polyimide tape coated on one or both surfaces of the fluorocarbon resin may be further included between the second insulating layer 23 and the insulator 24. .

On the other hand, the present invention will be described in more detail by explaining more specific examples and comparative examples. However, the present invention is not limited to the following examples and comparative examples, various forms of embodiments may be implemented within the appended claims. However, the following examples are intended to facilitate the implementation of the invention to those skilled in the art while at the same time making the disclosure of the present invention complete.

<Examples 1-3, Comparative Examples 1 and 2>

First, each of the three conductors is wrapped with mica tape, then wrapped with polyimide tape thereon, and then each of the resins of Chemical Formulas 1 to 3 is extruded, and the polyimide tape is wrapped with each of them to have a structure as shown in FIG. Insulated wire was prepared. In addition, according to the resins of Chemical Formulas 1 to 3, insulation wires prepared differently were divided into Examples 1 to 3.

Instead of the resin, the insulated wire formed by preparing an ethylene ethyl acrylate copolymer resin as an insulator was classified as Comparative Example 1, and the insulated wire formed by preparing a insulator using a high density polyethylene resin and then irradiating and crosslinking was divided into Comparative Example 2. It was. The thickness of the prepared Example and Comparative Example insulator was 0.01 inch (inch).

According to MIL-W 81381, the following blocking, moisture resistance, thermal shock resistance, shrinkage rate, flame retardancy, extrusion coating property and adhesive evaluation were performed, and are divided into Examples (1 to 3) and Comparative Examples (1 and 2). The characteristics of each insulated wire were evaluated. The evaluation results are shown in Table 1 below.

Blocking Evaluation

Each wire set in the above Examples and Comparative Examples was wound in three layers on a metal spool and left in a 200 ° C. oven for 24 hours. This evaluates the presence or absence of adhesion between insulators, and evaluates that the insulators do not stick together.

Moisture Resistance Evaluation

The insulation resistance was measured after leaving each wire set in the above Examples and Comparative Examples for 16 hours in a 70 ° C. oven having a relative humidity of 95 or more, and a value of 5 MΩ or more per 1000 feet was evaluated as excellent.

<Thermal Shock Resistance Evaluation>

The insulation at both ends of the 5 foot long wires set in the Examples and Comparative Examples was stripped off by about 1 inch. The wires were left in an air circulation oven at 150 ° C. for 30 minutes and then placed at −55 ° C. for 30 minutes. After repeating this process three times, the degree of shrinkage of the insulator was measured, and a value of 0.031 inches or less was evaluated as being excellent.

Shrinkage Rate Evaluation

After peeling off the insulators at both ends of each of the 12-inch-long wires set in the Examples and Comparative Examples, they were placed in an oven at 180 ° C. for 6 hours, and then the degree of shrinkage of the insulators was measured. .

<Flame retardancy evaluation>

A 60 degree tilt test was performed.

<Extrusion coating property evaluation>

It is an experiment to check whether the thin coating is possible during extrusion and the surface is extruded smoothly.

<Adhesive evaluation>

As an experiment to judge the degree of adhesiveness with insulating tape, it is evaluated that the tape should not be released when cutting the finished wire, and the insulation should not be separated when the surface is scratched.

division Example Comparative example One 2 3 One 2 Blocking Nonstick Nonstick Nonstick Attach Nonstick Moisture Resistant (MΩ) 18 15 16 6 10 Thermal Shock Resistance (Inch) 0.023 0.022 0.018 0.39 0.27 Shrinkage (Inch) 0.032 0.039 0.045 0.24 0.32 Flame retardant pass pass pass pass pass Extrusion coating Great Great Great dissatisfaction dissatisfaction Adhesive Great Great Great Good dissatisfaction

Referring to Table 1, since the wires according to Examples 1 to 3 do not adhere to each other between the insulators at a high temperature, the blocking characteristics are very excellent, but the wires according to Comparative Example 1 adhere to each other at high temperatures to satisfy the blocking characteristics. None was present, and the insulation burned black during the evaluation process. In addition, in the numerical values of thermal shock resistance and shrinkage rate, the wire according to the embodiment is much smaller than the wire according to the comparative example, and it can be seen that the resistance and the shrinkage rate are very excellent. In addition, the wire according to the embodiment is far superior to the extrusion coating property and adhesion than the wire according to the comparative example.

As described above, the insulated wire having an insulator made of the polyimide resin according to the present invention has excellent thermal stability, excellent heat resistance and numerical stability, excellent adhesiveness with insulating tape, and low shrinkage. It can be used for various purposes such as wire for signal and signal wire.

Claims (6)

Polyetherimide resin represented by the following formula (1) used as an insulator of the insulated wire, selected from the group consisting of a copolymer resin of siloxane and polyetherimide represented by the formula (2) and sulfonate polyetherimide resin represented by the formula (3) The polyimide resin which is either. <Formula 1>

<Formula 2>

<Formula 3>

Conductor; And an insulator surrounding the conductor; The insulator is insulated wire manufactured by molding the polyimide resin according to claim 1 by melt extrusion method. The method of claim 2, Interposed between the conductor and the insulator, A first insulating layer surrounding the conductor; And And a second insulating layer surrounding the first insulating layer and surrounded by the insulator. The method of claim 3, And an interlayer insulating layer comprising polyimide tape coated on one or both surfaces of the fluororesin between the second insulating layer and the insulator. The method according to claim 3 or 4, The first insulating layer is insulated wire, characterized in that made of any one selected from mica tape, polyimide tape, silicon coated mica tape, polyester tape, Teflon tape, silicone tape, asbestos tape and butyl tape. . The method according to claim 3 or 4, The second insulating layer, the insulated wire, characterized in that made of any one of the tape material selected from polyimide tape, mica tape, silicon coated mica tape, polyester tape, Teflon tape, silicone tape, asbestos tape and butyl tape .

Images