JPH02210713A - Insulated electric wire and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a polyimide covered insulated electric wire capable of molten extrusion molding and having improved heat resistance by using polyimide having a particular repetitive structure unit. CONSTITUTION:Polyimide having a repetitive structure unit expressed by the formula I is used as an insulator of an insulated electric wire. In the formula I, R denotes a tetravalent group selected from the group consisting of an aliphatic group, a cyclic aliphatic group, a monocyclic aromatic group, a non-condensed polycyclic aromatic group formed from aromatic groups connected with each other directly or by bringing member, and X denotes a single bond, a sulfur atom, a bivalent group which is a sulfonic group, a carbonyl group, an isopropylidene group, or a hexafluoroisopropylidene group. Thus, an electric wire with improved extrusion moldability, external appearance, and underwater withstand voltage, and further improved heat resistance and electrically insulating property can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an insulated wire using a specific polyimide as an insulator and a method for manufacturing the insulated wire.

[Conventional technology]

In recent years, the electrical and electronic industries have made remarkable progress, and in particular, the trend towards smaller and lighter equipment requires higher heat resistance for parts and insulating materials.

As such a material, aromatic polyimide has not only the highest heat resistance among organic polymers but also excellent mechanical properties. Polyimide (D
Manufactured by upont, trade name KAPTON, V[! 5PEL
), screw (4-7 mm/7 inch/L/): L-
Polyimide (manufactured by Ube Industries, Ltd., trade mark: Upilex), etc., which is composed of dianhydride and 3.3', 4.4°-biphenyltetracarboxylic dianhydride, etc. Since these polyimides are difficult to heat and melt, it is difficult to obtain insulated wires by melt extrusion.

[Problem to be solved by the invention]

An object of the present invention is to provide an insulated wire coated with a specific polyimide by melt extrusion molding and having excellent heat resistance.

[Means to solve the problem]

The present inventors have made extensive studies to achieve the above object. As a result, it was discovered that a polyimide-coated insulated wire that can be melt-extruded and has excellent heat resistance can be obtained by using polyimide consisting of a specific repeating structural unit, leading to the present invention.

That is, the present invention provides an insulated wire consisting of a conductor and an insulator covering the conductor, wherein the insulator has the general formula (1), (wherein R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic basis,
Indicates a tetravalent group selected from the group consisting of a monocyclic aromatic group, a fused polycyclic aromatic group, and a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. , X is a single bond, a sulfur atom, a sulfone group, a carbonyl group, an isopropylidene group, or a hexafluoroisopropylidene group.
An insulated wire characterized by being made of polyimide having a repeating structural unit represented by (indicating a valence group) and a method for manufacturing the same.

In the general formula (1), R4 is preferably a tetravalent group.

Hereinafter, the configuration of the present invention will be explained in detail.

The polyimide in the present invention can be obtained by a dehydration condensation reaction between a specific aromatic tetracarboxylic dianhydride and an aromatic diamine.

Aromatic tetracarboxylic dianhydrides used to obtain this polyimide include pyromellitic dianhydride, ethanetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, 1.
2,3.4-benzenetetracarboxylic dianhydride, 2,
3.6.7-Naphthalenetetracarboxylic dianhydride, 1
, 4,5.8-naphthalenetetracarboxylic dianhydride,
1.2.5.6-naphthalenetetracarboxylic dianhydride, 3,4,9.10-perylenetetracarboxylic dianhydride, 2.3,6.7-anthracenetetracarboxylic dianhydride, 1, 2.7.8-phenanthrenetetracarboxylic dianhydride, etc., 3.3', 4.4-biphenyltetracarboxylic dianhydride, 2.2', 3.3°-biphenyltetracarboxylic dianhydride, 3,3°, 4.4″-benzophenonetetracarboxylic dianhydride, 2,2°, 3.
3'-benzophenonetetracarboxylic dianhydride, 2.
2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, Bis(2,3-dicarboxyphenyl)ether dianhydride, bis(3I4-dicarboxyphenyl)sulfonic anhydride, bis(2,3-dicarboxyphenyl)sulfonic anhydride, 2,2-bis(
3,4-dicarboxyphenyl)1,1.1,3.3.
3-hexafluorobrovanni anhydride, 2.2-bis(3
,4-dicarboxyphenyl H,1,1,3,3,3-
Hexachloropropanihydride, 1,1-bis(2,3
-dicarboxyphenyl)ethane dianhydride, bis(2,
3-dicarboxyphenyl)methanihydride, bis(3
゜4-Dicarboxyphenyl) methane dianhydride, 4.4
'(p-phenylenedioxy)cyphthalic dianhydride, 4
．． Examples include compounds such as 4°-axial-phenylenedioxy)cyphthalic dianhydride. Preferably, for example, pyromellitic dianhydride, 3.3°, 4.4′-biphenyltetracarboxylic dianhydride, 3.3″, 4.4°-benzophenonetetracarboxylic dianhydride, 3. 3', 4
．． They are 4'-diphenyl ether tetracarboxylic dianhydride and p-phenylenedioxydi(4-phthalic acid) dianhydride.

These compounds may be used alone or in combination of two or more.

Further, aromatic diamines used to obtain polyimide include bis[4-(3-aminophenoxy)phenyl sulfide, bis[4-(3-aminophenoxy)phenyl sulfone, bis[4-(3-aminophenoxy) ) Phenyl 1-ketone, 4,4'-bis(3-aminophenoxy)biphenyl, 2,2-bis[4-(3-aminophenoxy)phenyl-propane or 2,2-bis[4-
(3-aminophenoxy)phenyl]-1,1,1,3
, 3,3-hexafluoropropane, and compounds selected from these can be used alone or in combination of two or more.

The aromatic diamine in the present invention can be used by replacing a part of the above diamine with another aromatic diamine.

Other aromatic diamines used instead are desirably less than 20 mol% of the total diamines.

Other aromatic diamines include, for example, p-phenylenediamine, -phenylenediamine, doaminobenzylamine, p-aminobenzylamine, 4.4'-diaminobiphenyl, 3.3'-diaminobiphenyl, 4.4'
-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4.4'-diaminodiphenylmethane, 3.3'-diaminodiphenylmethane, 1.1
-bis(4-aminophenyl)ethane, 1,1-bis(
3-aminophenyl)ethane, 2.2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2.2-bis(4-aminophenyl)
-1,1,1,3,3,3-hexafluoropropane,
2.2-bis-(3-aminophenyl)-1,1,1,
3,3,3-hexafluoropropane, 3.3'-diaminodiphenylsulfide, 4.4'-diaminodiphenylsulfide, 3.3'-diaminodiphenylsulfone, 3.3'-diaminobenzophenone, 4'4' -diaminobenzophenone, and the like.

The polyimide according to the present invention can be prepared by combining these aromatic tetracarboxylic dianhydrides and aromatic diamines by a conventional known method, for example, after suspending or dissolving the monomers or monomers in an organic solvent. Polyimide can be obtained by heating or chemically dehydrating, separating and purifying the product.

The obtained polyimide is used in powder form or in advance formed into granules.

As the conductor used to manufacture the coated wire of the present invention, a single metal element or an alloy having a resistivity of 20×10-”ΩI or less is used.

Examples of single metal elements include zinc, aluminum,
Gold, silver, copper, iron, nickel, niobium, etc. are used, and aluminum and copper are particularly preferably used. Also, as an alloy,
For example, silver, chromium, zirconium, tin, lead, tellurium,
Copper alloy containing 2% or less of one or more metal elements such as cadmium, beryllium, etc., or one or more metal elements such as magnesium, silicon, iron, zirconium, etc. An aluminum alloy containing 2% by weight or less, or a niobium alloy containing a metal element such as titanium, zirconium, tantalum, tin, or germanium is used.

Furthermore, the conductor used in the present invention is characterized by the oxidation and
In order to prevent an increase in specific resistance due to deterioration, heat generation of the conductor, voltage drop, etc., the surface thereof may be coated. Materials used for coating include tin, zinc, nickel, silver, aluminum, solder, copper, etc., with nickel, silver, etc. being particularly preferred.

The thickness of the conductor is such that its cross-sectional area is o, oot~2000s+
preferably in the range of 0.001 in.
If the cross-sectional area is less than 200 hm, it is undesirable because it will easily break during manufacturing or handling, and if the cross-sectional area exceeds 200 hm, the rigidity of the conductor will be extremely high and it will be difficult to handle.

The insulated wire of the present invention is produced by heating and melting the polyimide used in the present invention using a well-known melt extrusion molding device, coating the conductor using a conductor coating die typified by a cross-layered die, and cooling. Obtainable.

The polyimide used in the present invention is preferably dried before being used in melt extrusion, and it is particularly preferable to reduce the water content in the polyimide to 200 ppm or less.Normally, polyimide is stored in powder or pellet form. However, under normal storage conditions, the moisture content is about 0.5 to about 1χ. Even with such a moisture content, there is no problem when manufacturing a molded product by ordinary injection molding, etc. However, when manufacturing the insulated wire of the present invention by melt extrusion, the coating Moisture has a slight effect on the characteristics, that is, when the moisture content is 0.5 to 1χ, the appearance and electrical insulation properties (underwater dielectric strength) of the manufactured insulated wire become particularly problematic. By controlling the ratio to 200 pp- or less, it is possible to stably obtain an insulated wire with excellent characteristics.

Any method can be used to reduce the moisture content of polyimide to 200 pp or less, but for boat fishing, it must be kept at a temperature of 100°C or higher at which the polyimide does not melt, usually 250°C or lower for 3 to 24 hours. do. Furthermore, it is effective to replace the atmosphere with air, nitrogen, etc., and furthermore, the treatment may be performed under reduced pressure.

The melt extrusion temperature in the present invention varies depending on the polymer structure, but is usually in the range of 300 to 450°C, preferably in the range of 350 to 430°C. If the temperature is lower than 300°C, the resin will not melt and extrusion will become impossible.

In addition, if the temperature exceeds 450℃, the decomposition of the resin will progress, causing bubbles and
It is not preferable because the decomposed residue etc. impair its function as an insulator.

In the present invention, the coating thickness of the insulator is 0.01 to 5 m.
If the coating thickness of the insulator is less than 0.01 mm, the variation in coating thickness will be significant, causing electrical defects such as pinholes, so it is not preferable. There are difficulties in handling such as bending the electric wire.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Incidentally, the method for measuring the characteristic values of polyimide described in the Examples is as shown below.

(1) Glass transition temperature, melting point Glass transition temperature (Tg) and melting point (T-) were measured by DSC method. Tm was defined as the peak temperature of the melting curve.

(2) Measured using a melt viscosity enhancement type flow tester, 200 sec-
The apparent value of ' was calculated as the shear rate, and the apparent value at 400°C was calculated as the viscosity (unit: poise).

(3) Underwater withstand voltage 60H2 in water at 20°C according to JIS C3005
The test was conducted using an AC power source with a voltage increase rate of 100 OV/sin.

Polyimide 1 A reaction vessel equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube was charged with 368.4 g (1 mol) of 4,4'-bis(3-aminophenoxy)biphenyl and 2344 g of N,N-dimethylacetamide. 218.1 g (1 mol) of pyromellitic dianhydride was added under a nitrogen atmosphere.
was added in portions while being careful not to increase the solution temperature, and the mixture was stirred at room temperature for about 20 hours. The logarithmic viscosity of the polyamic acid thus obtained was 3.21 a/g. 30.3 g (0.3 mol) of triethylamine and 30.6 g (0.3 mol) of triethylamine were added to the polyamic acid solution thus obtained. ) of acetic anhydride was added over a period of about 30 minutes, and then stirred for about 30 minutes.To this solution was charged 2000 g of methanol, and
The polyimide powder was filtered off at 0°C. The obtained polyimide powder was washed with methanol and acetone, and then dried at 300° C. for 8 hours in a nitrogen atmosphere to obtain 517 g (yield: 94%) of polyimide powder. The obtained polyimide was a crystalline resin with a glass transition temperature of 271°C and a melting point of 389°C, and a melt viscosity of 5500 voids.

Polyimide 2 In a reaction vessel similar to the synthesis of polyimide 1, 4,4°-bis[4-(3-aminophenoxy)phenyl 1-1°1
．． 1,3,3.3-hexafluoropropane and pyromellitic dianhydride were reacted in a manner similar to the synthesis of polyimide 1 to obtain polyimide powder.

The obtained polyimide has a glass transition temperature of 247°C1
It is a crystalline resin with a melting point of 385°C and a melt viscosity of 4800
It was Boyz.

Polyimides 3 to 15 Polyimide powders were obtained using combinations of various aromatic tetracarboxylic dianhydrides and aromatic diamines shown in Table 1 in a manner similar to the synthesis of polyimide 1. Table 1 shows the glass transition temperature, melting point, and melt viscosity of the obtained polyimide powder.

Example 1 Polyimide 1 powder was dried at 150° C. for 24 hours, and the moisture content at this time was 180 pps+. This is processed using a screw compactor and a φ15 extruder (L/D
=22), heated and melted at an extrusion temperature of 420°C,
A 20 AWG silver-plated copper wire heated to 00° C. was supplied to the RAD die, and the copper wire withdrawal speed was adjusted so that the thickness of the insulating layer was approximately 0.2+w−. The take-up speed at this time was 1 m/gain. It came out from the covered wire. Afterwards, it was left to cool naturally. The extrusion conditions and the physical properties of the obtained insulated wire were as shown in Table 2, and the wire had excellent heat resistance.

Example 2 Polyimide 2 powder was dried at 150'C for 24 hours.
The moisture content at this time was 200 pp-, which was processed using a screw compactor and a φ15 m* extruder (L/E
l・22), heated and melted at a temperature of 400°C,
The pellets were extruded through a nozzle with an inner diameter of 2 mm (extrusion amount: 18.6 g/in), allowed to cool naturally, and cut to obtain pellets with a length of about 3 m. This pellet was extrusion molded in the same manner as in Example 1 to obtain an insulated wire. The wire had no problems in appearance and had excellent heat resistance.

Examples 3 to 15 Powders of polyimides 3 to 15 were melt-extruded in the same manner as in Example 1 to obtain insulated wires. The extrusion conditions and physical properties of the electric wire were as shown in Table 2, and the electric wire had no problems in appearance and had excellent heat resistance.

Comparative Example 1 The polyimide 1 powder used in Example 1 was melt-extruded in the same manner as in Example 1. However, the extrusion temperature was 460'C. Foaming and decomposed scum were generated due to decomposition of the resin, resulting in poor appearance.

Comparative Example 2 Polyimide l powder was dried at 90°C for 5 hours,
The water content at this time was 300 ppm. Using this, melt extrusion was performed in the same manner as in Example 1. Zero foaming was observed, and the appearance was extremely poor.

Comparative Example 3 Melt extrusion was performed in the same manner as in Example 2 using the polyimide 2 powder used in Example 2. However, the extrusion temperature is 470
Performed at °C. Foaming and decomposed scum were generated due to decomposition of the resin, and the appearance was extremely poor.

Comparative Example 4 Extrusion was carried out in the same manner as in Example 1 using the polyimide 7 powder used in Example 7 and at an extrusion temperature of 290°C, but extrusion was not possible.

〔Effect of the invention〕

In the present invention, by using a specific polyimide whose molding temperature is controlled to 300°C or more and 450°C or less and a moisture content of 200ppm or less, it has excellent extrusion moldability and the appearance of the wire coating layer, and also has excellent underwater withstand voltage. As described above, the insulated wire of the present invention has an insulator made of a novel polyimide that can be melt-extruded and has excellent heat resistance, and is an electric wire that has excellent heat resistance and electrical insulation.

Patent applicant (312) Mitsui Toatsu Chemical Co., Ltd. agent (7524) Shotabe Mogami

Claims (1)

[Claims] 1) An insulated wire consisting of a conductor and an insulator covering the conductor, where the insulator has a general formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R is the number of carbon atoms 2 or more aliphatic groups, cycloaliphatic groups,
Indicates a tetravalent group selected from the group consisting of a monocyclic aromatic group, a fused polycyclic aromatic group, and a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. , X is a single bond, a sulfur atom, a sulfone group, a carbonyl group, an isopropylidene group, or a hexafluoroisopropylidene group.
An insulated wire characterized by being made of polyimide having a repeating structural unit represented by (representing a valence group). 2) The polyimide having a repeating structural unit represented by the general formula [I] according to claim 1, in the general formula [I], R
There are ▲mathematical formulas, chemical formulas, tables, etc.▼,▲mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ Mathematical formulas,
The insulated wire according to claim 1, which has a chemical formula, table, etc. is a tetravalent group of ▼. 3) An insulated wire, characterized in that the polyimide according to claim 1 or 2 is molded by a melt extrusion method. 4) The insulation according to claim 3, characterized in that the polyimide according to claim 1 or 2 is heated and melted in an extruder at a temperature range of 300° C. to 450° C. to cover the conductor, and then cooled and solidified to form the insulation. Method of manufacturing electric wire. 5) The method for producing an insulated wire according to claim 4, wherein the polyimide according to claim 1 or 2 has a moisture content of 200 ppm or less immediately before being supplied to the extruder. 6) The insulated wire according to claim 1 or 2, wherein the insulating coating has a thickness of 0.01 to 5 mm.