JP3414788B2 - Fluororesin insulated wire - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororesin insulated wire, and more particularly, to a method of melt-molding on an electric conductor to improve electric characteristics. The present invention relates to a fluororesin insulated wire obtained by applying and firing a dispersion obtained by dispersing a mixture of a possible fluororesin and polytetrafluoroethylene resin in a solvent. 2. Description of the Related Art In order to improve the transmission amount / size ratio by miniaturizing and increasing the density of electric wires, and mainly to obtain electric wires having excellent transmission characteristics at high frequencies, a fluororesin is used for an ultrafine electric conductor. Recently, the demand for a coaxial wire having a very thin coating on the wire has been increasing. As a method for forming an insulating coating of a resin on an electric wire, there is a method in which a resin is melted and extruded. But,
This method has the following problems. That is, as an extrudable resin,
Although resins having extremely low melt viscosities are commercially available, generally, when the melt viscosities are lowered, the stress crack resistance is lowered, so that the melt viscosities cannot be reduced to a certain level or less to maintain practical characteristics. Therefore, there is a problem that only coating up to about 20 μm can be performed due to the characteristics of the resin. As a resin, a polytetrafluoroethylene resin (PTF) having the best electric characteristics among fluororesins is used.
It is best to use E), but this polytetrafluoroethylene resin has an extremely high melt viscosity, so that ordinary melt molding is impossible. [0006] Due to the above-mentioned problems, each of PTFE, FEP (ethylene tetrafluoride-6-propylene fluorinated copolymer) and PFA (ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer) is used instead of the melt extrusion coating. A method has been attempted in which a thin film is coated by applying a dispersion prepared by dispersing the compound in water or an organic solvent, followed by firing. However, since the PTFE dispersion melts and flows and does not integrate even after firing,
Binder resin is required. As this binder resin,
Usually, a high melting point engineering plastic such as polyamideimide is used. [0008] In the case where the PTFE dispersion is applied to an electric conductor and baked, a binder resin is required as described above. However, there is a problem that it is not desirable. [0009] The above-mentioned conventional problems
In view of the above, the present invention is to disperse fluororesin fine powder in a solvent
Fluororesin dispersion applied to electrical conductor
Can be melted and molded into a fluorinated resin insulated wire
Ethylene-6-fluoride propylene
Rene copolymer (FEP) or ethylene tetrafluoride perf
Alkyl vinyl ether copolymer (PFA)
Polytetrafluoroethylene resin (PTFE)
/ FEP or PTFE / PFA mixing ratio (weight ratio)
What was mixed so as to be 2 to 14 was dispersed in the solvent.
Coating and firing on the electrical conductor
Insulation coating, dielectric loss tangent at 100kHz, 100 ℃
(Tan δ) is 9 × 10 ^{−5 to} 3 × 10 ⁻⁵ and elongation is 290.
% To 260%.
Things . As described above, in the present invention, a solvent obtained by mixing a melt-moldable fluororesin (FEP or PFA) with a polytetrafluoroethylene resin (PTFE) at a ratio of 2 to 14 is used. FEP, PF
By using A as a binder, PTFE can be covered and fixed to the electric conductor. The above P as a melt-moldable fluororesin
FA and FEP have slightly lower electrical properties than PTFE, but have a higher P than other resins when compared with other resins.
Since the electric characteristics are close to those of TFE, the electric conductor can be coated in such a manner that the electric characteristics of PTFE itself are not impaired as much as possible. The dispersion applied to the electric conductor is as follows:
A mixture of PTFE, FEP or PFA is dispersed in a liquid, and the medium may be water or an organic solvent. Further, the particle size and concentration of the powder are not particularly limited. EXAMPLE A dispersion in which only PFA and FEP powders are dispersed in a solvent, and PFA or FEP and PT
By mixing the FE prepared dispersion dispersed in a solvent, Ag of these dispersions 0.5 mm ^phi
It was applied on a plated copper wire and fired to produce a fluororesin-coated electric wire. The coating conditions of the dispersion are as shown in Table 1. [Table 1] All of the dispersions used in Table 1 are dispersed in an aqueous solvent and contain a surfactant for dispersion. Table 2 shows examples in which various dispersions shown in Table 1 were applied to an electric conductor and baked. [Table 2] As is evident from Table 2, Example 1 had PTFE and FEP.
And the mixing ratio (PTFE / FEP) is 2/1, and 10
The value of the dielectric loss tangent (tan δ) at 0 KHz, 100 ° C. is 9 ×
It was 10 ^-5 . The elongation at break in the tensile test was 29.
It was 0%. In Example 5, the mixing ratio between PTFE and PFE was 2/1, the value of the dielectric loss tangent was 7 × 10 ⁻⁵ , and the elongation was 290%. Examples 2, 3, and 4 are examples in which the mixing ratio of PTFE and FEP is changed to 6/1, 10/1, and 14/1, and Examples 6, 7, and 8 are PTFE and FEP. This is the case where the mixing ratio with PFA was changed to 6/1, 10/1, and 14/1. As is clear from Table 2, according to the present embodiment, tan δ can be reduced without sacrificing mechanical properties (elongation at break in a tensile test), and electrical properties can be impaired. Not something. As will be understood from the above description of the embodiments, according to the present invention, the electric power can be obtained without sacrificing the mechanical characteristics and without impairing the electric characteristics of PTFE. It is possible to obtain a fluororesin insulated wire obtained by coating a conductor with PTFE very thinly.

Claims (1)

(57) [Claims] [Claim 1] A fluororesin fine powder is dispersed in a solvent.
Fluororesin dispersion applied to electrical conductors and fired
Fluorine resin insulated wire made of
Ethylene tetrafluoride-6-propylene fluoride as fluorine resin
Copolymer (FEP) or perfluorotetrafluoroethylene
Against alkyl vinyl ether copolymer (PFA)
Polytetrafluoroethylene resin (PTFE) is converted to PTFE / F
EP or PTFE / PFA mixing ratio (weight ratio) is 2
Disperse the mixture in the solvent so that the mixture becomes 14.
Coating and firing on electrical conductors for insulation
A coating is applied and the dielectric loss tangent (t
an δ) is 9 × 10 ^{−5 to} 3 × 10 ⁻⁵ and elongation is 290% or more.
The insulating coating is provided extremely thin so as to be 260%.
A fluororesin insulated wire characterized by the following .