JPH087656A - Insulation material for low voltage wire and low voltage wire - Google Patents

Abstract

(57) [Summary] [Structure] Syndiotactic pentad fraction 0.7
The insulating material for low voltage electric wire containing the syndiotactic polypropylene which is the above and whose MFR is 0.1 to 20 g / 10 minutes. A low-voltage electric wire using the insulating material for a low-voltage electric wire. [Effect] The insulating material for a low voltage electric wire of the present invention has excellent electrical characteristics and flexibility. Further, even if the insulating material is rapidly cooled after being processed, it exhibits excellent electric characteristics, so that the processing speed can be increased and the production efficiency can be improved. Furthermore, the low-voltage electric wire using the insulating material has excellent electric characteristics and flexibility, and is also excellent in underwater breakdown resistance and cut-through property. Therefore, the insulating material for a low-voltage electric wire of the present invention is suitable as an insulating material for a low-voltage electric wire for various devices, particularly a low-voltage electric wire for an underwater motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating material for a low voltage electric wire and a low voltage electric wire using the same. For more information,
The present invention relates to an insulating material for low-voltage electric wires containing syndiotactic polypropylene and a low-voltage electric wire using the same.

[0002]

2. Description of the Related Art A blend of isotactic polypropylene / ethylene propylene rubber (hereinafter referred to as "i ---") is used as an insulating material in low-voltage electric wires (for example, electric wires for equipment, especially electric wires for underwater motors).
(Also referred to as "PP / EP rubber") has been conventionally used. However, the low-voltage electric wire using the insulating material composed of the i-PP / EP rubber has a problem that it is inferior in the underwater fracture resistance and the cut-through property. That is, a low-voltage electric wire using i-PP / EP rubber has a problem that dielectric breakdown is likely to occur when used for a long time in water.

An object of the present invention is to provide an insulating material for a low voltage electric wire which does not have the above problems and has excellent electric characteristics, and a low voltage electric wire using the same.

[0004]

Means for Solving the Problems In order to achieve the above object, the present inventors have examined the applicability of various materials to insulating materials for low voltage electric wires, and found that an insulating material composed of the following syndiotactic polypropylene was Conventional i-PP /
It has electrical characteristics superior to an insulating material made of EP rubber, and a low-voltage electric wire made of the insulating material has sufficient flexibility, and has excellent underwater breakdown resistance and cut-through properties. This has led to the completion of the present invention.

That is, the present invention has a syndiotactic pentad fraction of 0.7 or more and an MFR of 0.1 to 0.1.
The present invention relates to an insulating material for a low-voltage electric wire, which contains 20 g / 10 minutes of syndiotactic polypropylene. The present invention also relates to a low voltage electric wire, characterized in that the insulating material for a low voltage electric wire is used.

The syndiotactic polypropylene (hereinafter referred to as "s-P" used in the insulating material for low-voltage electric wires of the present invention
(Also referred to as “P”) is polypropylene having a syndiotactic structure, and polypropylene includes not only a homopolymer of propylene but also a copolymer of propylene and other olefins. The s-PP is preferably a homopolymer.

The syndiotactic pentad fraction of s-PP used in the present invention must be 0.7 or more. Here, the syndiotactic pentad fraction refers to 20.2 based on tetramethylsilane in a ¹³ C-NMR spectrum measured at 135 ° C. in a 1,2,4-trichlorobenzene solution at 67.8 MHz.
It refers to the ratio of the peak intensity attributed to all methyl groups of the propylene unit of the peak intensity observed in ppm (peak intensity of methyl group attributed to syndiotactic pentad chain).

The syndiotactic pentad fraction is 0.
S-PP of less than 7 has a low melting point and also lowers electrical breakdown strength and mechanical properties, and is not preferable as an insulating material for low voltage electric wires. The syndiotactic pentad fraction is preferably 0.8 to 0.95, and more preferably 0.86 to 0.95 from the viewpoint of electrical characteristics, mechanical characteristics, extrusion processability, and the like.

Also, the s-PP has its MFR [melt flow rate; ASTM-D-1238 (load 10 kg
f, temperature 230 ° C)] is 0.1 to 20 g / 10
Must be minutes. M over 20g / 10 minutes
The s-PP having FR has too much fluidity at high temperature, and conversely has s-PP having MFR of less than 0.1 g / 10 min.
-PP has too low a fluidity, and in any case, it has a problem in workability. The MFR is preferably 0.3 to 15 g / 10 minutes, more preferably 0.5 to 10 g / 10 minutes from the viewpoint of workability.

The weight average molecular weight of the s-PP is preferably 3,000 to 400,000, more preferably 10,000 to 200,000 from the viewpoint of extrudability.

There is no particular limitation on the method for producing the s-PP. That is, as the polymerization catalyst, an organometallic complex catalyst having a symmetrical or asymmetrical molecular structure, for example, a stereospecific polymerization catalyst such as a metallocene compound is used. Also, the polymerization conditions are not particularly limited, and the polymerization can be performed by a method such as a bulk polymerization method, a gas phase polymerization method, a solution polymerization method using an inert solvent, or the like.

The low voltage electric wire insulating material of the present invention may include, if necessary, an antioxidant or stabilizer such as a hindered phenol type, an amine type or a thioether type, and an amide type or a hydrazide type copper damage inhibitor. , Benzophenone-based, benzoin-based, etc. UV inhibitors, higher fatty acid-based or metal salt-based lubricants, processing aids, organic / inorganic pigments, organic / inorganic flame retardants, and fillers such as silica and clay. The additives usually used for plastics may be added.

The insulating material for low voltage electric wires of the present invention containing s-PP has excellent electrical characteristics (impulse breakdown characteristics, AC breakdown characteristics, AC breakdown characteristics in water, volume resistivity, dielectric constant, etc.). It has sufficient flexibility to be used for low voltage electric wires. It also has excellent underwater fracture resistance and cut-through properties.

The low voltage electric wire of the present invention comprises the above insulating material for a low voltage electric wire. The low-voltage electric wire referred to in the present invention refers to an electric wire for supplying electric power of less than 3.3 kV, for instrumentation, or for control. Specific examples include electric wires for various devices, electric wires for various circuits, electric wires for underwater motors, and wire harnesses.

In the low voltage electric wire of the present invention, the insulating material for a low voltage electric wire is mainly used as an insulating layer. The thickness (insulation thickness) of the insulating layer of the low-voltage electric wire is preferably 0.1 to 5.0 mm, more preferably 0.2 to 4.0 mm, from the viewpoint of electrical insulation performance.

As the conductor used for the low-voltage electric wire, known conductors such as pure copper and copper alloy conductors can be cited. In addition to these conductors, plated conductors,
Examples thereof include those plated with nickel, silver, and tin, and those plated with nickel are particularly preferable. Furthermore, a material obtained by baking enamel or the like on the conductor may also be used.

In the low voltage electric wire of the present invention, an insulating layer made of the above low voltage electric wire insulating material is formed on a conductor (for example, a copper single wire, a copper twisted wire, a tin-plated copper twisted wire, an enamel-baked copper single wire, etc.) by an extruder or the like. It can be produced by continuous extrusion coating or the like.

The electric wire using the insulating material containing s-PP has an impulse breakdown electric field strength of about 8 at room temperature as compared with the electric wire using the conventional insulating material containing i-PP / EP rubber.
0 to 130% higher, room temperature alternating current (AC) breakdown electric field strength is about 30 to 65% higher, and cut-through property is about 20 to 50%.
%, The underwater destruction resistance (underwater voltage life) is about 30 to 8
It improves by 0%.

In the case of producing a low voltage electric wire from the insulating material for a low voltage electric wire containing the above s-PP, even if the insulating material is melted and molded and then gradually cooled (-10 ° C / min), it is cooled in 0 ° C ice water. It shows excellent electrical characteristics even when rapidly cooled. That is, when the low-voltage electric wire insulating material of the present invention is used to manufacture a low-voltage electric wire having a thin insulation thickness, rapid cooling can be performed, and thus the processing speed (electric wire manufacturing speed) can be increased to improve the production efficiency. It is possible to obtain a low-voltage electric wire having excellent electric characteristics.

[0020]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Examples 1-8, Comparative Example 1 The syndiotactic pentad fraction and M shown in Table 1
Insulating materials A to I made of various s-PP (homopolymers) having FR are melted and molded at 180 ° C. for 15 minutes using a compression molding machine, and then slowly cooled (cooling at room temperature) or in 0 ° C. ice water. It was rapidly cooled to obtain a 0.3 mm thick sheet.

Comparative Example 2 Instead of s-PP, i-PP / EP rubber (weight ratio 70 /
A 0.3 mm thick sheet was obtained in the same manner as in the above example except that the insulating material J consisting of 30) was used.

In the insulating materials A to J, each property of the polymer was measured as follows. The syndiotactic pentad fraction was measured by ¹³ C-NMR measured at 67.8 MHz with a 1,2,4-trichlorobenzene solution at 135 ° C.
In the spectrum, the ratio of the peak intensity attributed to all the methyl groups of the propylene unit of the peak intensity (peak intensity of the methyl group attributed to the syndiotactic pentad chain) observed at 20.2 ppm based on tetramethylsilane. Was calculated. MFR is ASTM-D-123
8 (load 10 kgf, temperature 230 ° C.), and the melting point was measured using the peak / top temperature according to the DSC method. The molecular weight was measured by gel permeation chromatography.

Further, each sample obtained in the above Examples and Comparative Examples was subjected to an impulse breakdown test and an AC breakdown test with an improved McKeown electrode system. In the impulse breakdown test, the negative impulse standard wave of 1 × 40 μsec was used as the initial value with 70% of the expected breakdown voltage as the initial value.
The voltage was applied by the step-up boosting method of applying kV / 3 times.
In the AC breakdown test, 70% of the expected breakdown voltage was used as the initial value, and the voltage was applied by the step-up boosting method of applying 1 kV / 1 minute. In each of the impulse breakdown test and the AC breakdown test, data of 10 samples was collected for each condition, and after Weibull analysis, the breakdown value at a breakdown probability of 63.3% was taken as the breakdown voltage value of the sample. The results are shown in Table 1.

[0025]

[Table 1]

As can be seen from Table 1, the low voltage electric wire insulating material of the present invention exhibits good electric breakdown characteristics even when gradually cooled or rapidly cooled at 0 ° C.

Examples 9 to 16 and Comparative Examples 3 to 4 Using insulating materials A to J as insulating layers, a 30 mmφ extruder was used to deposit 0.05 mm thick polyester enamel on copper twisted wires with a conductor diameter of 2.2 mm. , 0.6mm thickness by continuous extrusion coating (extrusion temperature condition = C ₁ : 1
80 ° C, C ₂ : 185 ° C, C ₃ : 181 ° C, D: 180
℃), a low voltage electric wire for underwater motor winding was obtained.

The low-voltage electric wires obtained in the above-mentioned examples had a good appearance and had sufficient flexibility, like the conventional low-voltage electric wires of Comparative Example 4.

With respect to the low voltage electric wires obtained in the above Examples and Comparative Examples, the underwater fracture resistance and the cut-through property were measured as follows. As for the underwater breakdown resistance, the above low-voltage wire was immersed in water (AC6V, water temperature 60 ° C.), and the time (underwater charge life) until dielectric breakdown was measured. Also,
The cut-through property was measured at 80 ° C., a load of 450 g × 2, and a direct current voltage (DC) of 1 kV at 80 ° C. based on the test method specified in UL AWM3239, and the time until dielectric breakdown was measured. Table 2 shows the results.

[0030]

[Table 2]

As can be seen from Table 2, the low voltage electric wire of the present invention exhibits excellent underwater fracture resistance and cut-through properties.

[0032]

The insulating material for low voltage electric wire of the present invention has excellent electric characteristics and flexibility. Further, even if the insulating material is rapidly cooled after being processed, it exhibits excellent electric characteristics, so that the processing speed can be increased and the production efficiency can be improved. Furthermore, a low-voltage electric wire using the insulating material has excellent electrical characteristics,
It has flexibility, and also has excellent underwater fracture resistance and cut-through properties. Therefore, the insulating material for a low-voltage electric wire of the present invention is suitable as an insulating material for a low-voltage electric wire for various devices, particularly a low-voltage electric wire for an underwater motor.

Claims (2)

[Claims] 1. A syndiotactic pentad fraction of 0.7 or more and an MFR of 0.1 to 20 g / 10.
An insulating material for low-voltage electric wires, characterized in that it contains the syndiotactic polypropylene which is a component. 2. A low-voltage electric wire comprising the insulating material for a low-voltage electric wire according to claim 1.