JPH02250209A - Insulated electric wire - Google Patents

Abstract

PURPOSE:To obtain excellent mechanical characteristics and electrical characteristics by forming an insulation layer of polyether etherketone(PEEK) whose specific gravity is 1.28 or larger. CONSTITUTION:The electric wire mentioned in the title has an insulation layer formed of PEEK having specific gravity of 1.28 or larger. The specific gravity herein refers to one measured at 23 deg.C, and the specific gravity and the crystallinity of PEEK univocally correspond to each other wherein specification of the specific gravity of PEEK specifies the crystallinity so that its mechanical characteristics and electrical characteristics can be specified. In order to constitute an insulation layer of PEEK having the specific gravity of 1.28 or larger, there are methods employed, whereby an insulation layer of predetermined thickness is formed on a preheated conductor by extrusion-coating method and crystallinity is improved by making the ratio of cooling the insulation layer slow, or the crystallinity is improved by introducing the insulation layer into a heating furnace kept at the crystallization temperature of PEEK. An insulated electric wire having excellent mechanical characteristics and electrical characteristics can be thus obtained.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to polyether ether ketone (hereinafter referred to as PE
It is abbreviated as EK. ) An insulated wire having an insulating layer consisting of:

[Conventional technology]

PEEK has a high melting point of 340°C or higher and
Since it has excellent thermal stability in the high temperature range of ~300°C, it is expected to be used as a highly heat-resistant insulating material. Also, as an electrical insulator, AC short-term breakdown stress is 1.
It has more than OOkV/am and is promising as a thin insulating material.

For this reason, it has already been proposed to extrude and coat PEEK as an insulating layer for heat-resistant insulated wires.

[Problem to be solved by the invention]

By the way, PEEK is a crystalline polymer, and its mechanical properties, electrical properties, etc. vary greatly depending on its degree of crystallinity.

For this reason, when using PEEK as an insulating layer for insulated wires, it is necessary to know in what range its crystallinity should be in order to satisfy the various properties required for the insulating layer. come.

However, such considerations have not been made in the past.

[Means to solve the problem]

The present inventors conducted a detailed study on the relationship between I) E E K's crystallinity, mechanical properties, and electrical properties, and found that by forming an insulating layer with PEEK having a specific gravity of 1.28 or more, It was discovered that ambiguous mechanical and electrical properties could be obtained.

That is, the insulated wire of the present invention has a specific gravity of 1.28 or more.
It has an insulating layer made of EEK. The specific gravity here refers to that measured at 23°C and is expressed as d,3.

1) There is a unique correspondence between the specific gravity (dl3) and crystallinity of E E K, and when the crystallinity is 0%, dz3""12
63, and when the crystallinity is 100%, d t3 = 14
01 (Polymer, Vol. 24, 1983)
It has been reported that. Therefore, the specific gravity of PEEK (
By specifying dl3), its crystallinity is specified, and in turn, its properties such as mechanical properties and electrical properties are specified.

Figure 1 shows the relationship between PEEK's specific gravity and tensile strength, Figure 2 shows the relationship between PEEK's specific gravity and cut-through strength, and Figure 3 shows the relationship between PEEK's specific gravity and cut-through strength.
The figure shows the relationship between the specific gravity of PEEK and the dielectric breakdown voltage. As is clear from these graphs, the changes in tensile strength, cut-through strength, and AC breakdown voltage all show an inflection point at dl3 of 1.28, and dl
3 is 1. ．． It can be seen that there is a significant improvement in values of 28 and above.

Therefore, by forming the insulating layer with PEEI having a dl3 of 1.28 or more, the insulated wire has excellent mechanical properties and electrical properties. Of course, dl
The upper limit of 3 is 1,401 based on the crystallinity.

To construct an insulating layer using PEEK with a dl3 of 1.28 or more, an insulating layer of a predetermined thickness is formed on a preheated conductor by an extrusion coating method, and the cooling rate of the insulating layer is slowed down to reduce the crystallinity. A method of increasing the degree of crystallinity or a method of increasing the degree of crystallinity by introducing it into a heating furnace maintained at the crystallization temperature of PEEK are adopted.

Moreover, in the insulating layer of the insulated wire of this invention, PEE
In addition to K, various additives such as fillers and colorants may be added. In this case, the specific gravity of the insulating layer changes as a result, but the contribution of the additive may be subtracted from the specific gravity of the additive and the addition m so that the specific gravity of PEEK alone becomes 1.28 or more.

Furthermore, the insulated wire of the present invention has a specific gravity of 1.2.
Any coating may be formed on the insulating layer made of PEEK having a particle size of 8 or more, and any resin coating may be formed between the conductor and the PEEK insulating layer.

[Example] An annealed copper wire with a diameter of 0.8 m + n was preheated to 250'C and sent to the cross of the extruder through a rad tie, and the extrusion temperature was 390°C.
Extrusion coating PEEK at 200°C to 22°C immediately
The PEEK was introduced into a slow cooling furnace (furnace length 5I2) at 0° C., and an insulated wire having an insulating layer made of PEEK with a thickness of 0.2 mm was obtained by slowly cooling the PEEK.

When the insulating layer of this insulated wire was partially peeled off and the specific gravity was determined by the sulfuric acid method, it was found to be -1,316 dl.

The AC breakdown voltage of this insulated wire was 25 kV, and the tensile strength was lt,5 to 97xx''.

For comparison, the dZa of the insulating layer was similarly determined for an insulated wire in which the PEEK was rapidly cooled by immediately introducing it into a cooling water tank at 20°C after the extruded wave layer, and found that dts = 1.2
It was 68. The AC breakdown voltage of this insulated wire is 18
kV, and the tensile strength was 8.9 to 9 ha''.

〔Effect of the invention〕

As explained above, the insulated wire of the present invention has a specific gravity of 1
, 28 or more, it has flattened mechanical and electrical properties.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the specific gravity of PEEK and tensile strength, Figure 2 is a graph showing the relationship between the specific gravity of PEEK and cut-through strength, and Figure 3 is the relationship between the specific gravity of PYεEK and AC dielectric breakdown stress. This is a graph showing.

Claims (1)

[Claims] An insulated wire characterized by having an insulating layer made of polyetheretherketone having a specific gravity of 1.28 or more.