JP2800194B2 - Small diameter insulated wire - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a thin and small-diameter flame-retardant insulated wire.

[Prior Art] In recent years, miniaturization and space saving of electric and electronic devices have been remarkably advanced. In order to further reduce the size, it is important to reduce the diameter of the wires and cables used there.

In order to reduce the diameter of the electric wire, it is sufficient if the conductor can be made thinner and the insulator thickness can be made thinner. In addition, flame retardancy of electric wires is also important for electric and electronic devices. In addition, electrical insulation, dielectric constant,
It is necessary to satisfy electrical characteristics such as dielectric breakdown strength and mechanical characteristics such as wear resistance.

As an insulator material of an ordinary wire having a diameter of 1 mmφ or more, a material obtained by flame retarding polyethylene having a small dielectric constant and excellent electric characteristics is used. In addition, since wires for electric / electronic devices must be easily wired, flexible wires are desired. For example, a flame-retardant insulating composition obtained by adding a halogen-based flame retardant and antimony trioxide to polyethylene is generally used.

However, when a thin and thin electric wire having an outer diameter of 1 mmφ or less and an insulation thickness of 200 μm or less was manufactured, the following defects became apparent.

First, the probability of dielectric breakdown has increased significantly. Also, the wear resistance of the electric wire was significantly reduced. In addition, manufacturing problems became apparent. That is, in the process of extruding an electric wire, the appearance is significantly roughened at a relatively high speed, but at a speed that is not a problem when extruding an electric wire having an outer diameter of 1 mmφ and a thickness of 200 μm or more. In addition, it has been found that defects such as a remarkable decrease in the elongation of the insulator occur, and that the production speed is greatly restricted.

[Problem to be Solved by the Invention] As described above, the conventional technique uses an outer diameter of 1 mmφ or less,
In addition, flame-retardant thin wires having an insulation thickness of 200 μm or less have drawbacks such as withstand voltage characteristics, abrasion resistance, rough appearance during high-speed extrusion, and reduced elongation.

The present invention has been made in view of such a point, and an object of the present invention is to provide a flame-retardant thin electric wire having a small diameter.

[Means and Actions for Solving the Problems] The present invention has a yield point stress of 150 kg / cm ² or more and a melting point of 1 kg / cm ² or more.
Insulated with a composition containing 99 to 85 parts by weight of polyethylene at 15 ° C or higher and 1 to 15 parts by weight of an ethylene-α olefin copolymer, and containing a total of 10 to 30% by weight of a halogen-based flame retardant and an inorganic-based flame retardant auxiliary. The purpose is to form a body, whereby a flame-retardant thin-walled thin-walled electric wire excellent in practicality can be obtained.

[Example] The use of polyethylene having a yield point stress of 150 kg / cm ² or more and a melting point of 115 ° C. or more is extremely effective in improving wear resistance. Polyethylene whose yield point stress and melting point do not satisfy the above-mentioned values has poor abrasion resistance. This is probably because the abrasion of the thin material requires not only mechanical strength but also resistance to frictional heat. Of course, when either the condition of the yield point stress or the condition of the melting point does not satisfy the above value, the wear resistance is inferior.

Examples of the ethylene α-olefin copolymer include TAFMA of Mitsui Petrochemical Co., Ltd. The mixing ratio of the polyethylene and the ethylene α-olefin copolymer must be in the range of 99: 1 to 85:15 by weight.

The present inventor has found that the appearance during high-speed extrusion is improved by incorporating an ethylene α-olefin copolymer. No effect is observed when the content is less than 1%, and the wear resistance of the wire is impaired when the content is more than 15%, and the dielectric breakdown characteristics are slightly lowered. 3-10% was the more preferred amount.

Of course, improvement in the appearance of high-speed extrusion by selection of polyethylene or blending of polyethylene is important. However, the thickness is 200μm or less, the outer diameter is 1mmφ
In the following small-diameter electric wires, these means have limitations and high-speed extrusion of several hundred m / min is difficult. Further, there is a disadvantage that the elongation of the insulator of the high-speed extruded electric wire is significantly reduced.

The present inventor has found that the blending of polyethylene and the ethylene α-olefin copolymer in a specific ratio has a remarkable effect on them, and has enabled small-diameter high-speed extrusion.

Examples of the halogen-based flame retardants include brominated flame retardants such as hexabromobiphenyl ether, decabromobiphenyl ether, hexabromocyclododecane, bis (bromoethyl ether) tetrabromobisphenol A, hexabromobenzene, hexabromobiphenyl, and tetrabromobisphenol S. Hexabromobenzene, Pyrogard SP103
(Daiichi Kogyo Seiyaku Co., Ltd.), Pyroguard SP700 (Daiichi Kogyo Seiyaku Co., Ltd.), Fireguard 3000 (Teijin Kasei Co., Ltd.), Cytex BT93 (Cytex Co., Ltd.)
And chlorine-containing flame retardants such as Dechlorane Plus 315, Dechlorane Plus 25, Dechlorane Plus 2520, Dechlorane 603, and Dechlorane 604 (manufactured by Hucca Chemical Co., Ltd.), but are not limited thereto. However, chlorinated paraffin and chlorinated polyethylene are excluded.

Examples of the inorganic flame retardant aid include antimony trioxide, antimony pentoxide, silica, NaSbO ₃ , tin oxide, tin hydroxide, molybdenum oxide, ammonium molybdate, zirconium oxide, and zirconium hydroxide.

The halogen-based flame retardant and the inorganic flame retardant auxiliary are used in combination.
And it is necessary to mix with the above-mentioned polyethylene in the total of 10 to 30% by weight of both. If the content is 30% by weight or more, the withstand voltage characteristics are significantly reduced. Also, 10% by weight
Below, the flame retardancy will be impaired.

Hereinafter, Examples and Comparative Examples of the present invention will be specifically described. Examples 1 to 6 shown in Table 1 were obtained by twisting seven tin-plated copper wires having an outer diameter of 0.102 mm on a conductor using a 40 mm extruder.
And the flame-retardant polyethylene compound having the composition of Comparative Examples 1 to 7 was extrusion-coated at a speed of 300 m / min on a core wire heated to a temperature of 100 ° C. so as to have an insulation thickness of 0.12 mm to prepare an electric wire having an outer diameter of 0.54 mm. Then, each sample was used.

Then, appearance roughness at this time was visually observed. Table 1 shows the polyethylene and the flame retardant used. For polyethylene, the measurement results of yield point stress and melting point are also shown.

The yield point stress was measured according to the test method of JIS K-6760 polyethylene.

Melting point was measured by PerkinElmer's differential scanning calorimeter DSC.
Measurement was performed at a heating rate of 10 ° C./min with Form II, and the endothermic peak position was determined.

The abrasion resistance test was performed using the apparatus shown in FIG.
That is, a load 1 of 500 g presses a 4 mmφ rod-shaped pin electrode 2, which is reciprocated at a rate of 60 times / min over a 30 mm section on a conductor 4 coated with a horizontally placed insulator 3 as a sample. The determination is made based on the number of times until the pin electrode 2 and the conductor 4 are short-circuited. Reference numeral 5 denotes a lamp, and reference numeral 6 denotes a battery. The battery 6 has a positive electrode connected to the conductor 4 of the device under test and a negative electrode connected to the pin electrode 2 for testing.

The withstand voltage test was performed by the method shown in FIG. In this method, a water tank 8 is filled with water 9, each sample to be tested is immersed in the water, and a voltage of 3 kV is applied from an electrode 10 to measure a dielectric breakdown.

The flame retardancy test was performed by the method shown in FIG. That is,
A flame 14 is applied to the wire sample 12 having both ends supported horizontally using a burner 13, and after ignition, the flame 14 is removed.
Judgment is made based on whether the flame naturally extinguishes before the flame spreads to both ends of the 30 cm section.

The polyethylene used in Table 1 was manufactured by Examples 1, 5, 6 and Comparative Examples 1, 4, and 5 by Hiisex 5305 manufactured by Mitsui Petrochemical Co., Ltd.
E, Example 2 and Comparative Example 2 are Shorex 5003 manufactured by Showa Denko KK, Example 3 and Comparative Example 3 are Linirex AM-1720 manufactured by Nippon Petrochemical Co., Ltd., and Example 4 is also Linirex AF- At 3710, Comparative Example 6
AF-3310 and Comparative Example 7 are Ube B028 of Ube Industries, Ltd.

The ethylene α-olefin copolymer used in Example 1 was Tafuma A4090, and the others were Tafuma A-4085 (manufactured by Mitsui Petrochemical Co., Ltd.).

Dechlorane Plus 25 (manufactured by Hooker Chemical Co., Ltd.) was used as the halogenated flame retardant.

 Antimony trioxide was used as an inorganic flame retardant aid.

Table 2 summarizes the measurement results of the examples and comparative examples.

In Examples 1 to 6, the yield point stress was 150 kg / cm ² or more and the melting point was 1
A mixture of polyethylene having a temperature of 15 ° C. or higher, an ethylene α-olefin copolymer and a flame retardant. In any case, the appearance was not roughened even by high-speed extrusion at 300 m / min. The insulator elongation was also sufficient. In addition, good results were obtained in all of the wear resistance, dielectric breakdown resistance, and flame retardancy.

Comparative Examples 1 to 3 are cases where no ethylene α-olefin copolymer is added. In comparison with Examples 1 to 6, the appearance was rough and the insulator elongation was small.

Comparative Examples 4 and 5 showed good appearance. However, Comparative Example 4
Is low in abrasion resistance because the ethylene α-olefin copolymer is as large as 20%.

 Comparative Example 5 is inferior in withstand voltage characteristics because the flame retardant amount is 40%.

In Comparative Examples 6 and 7, the polyethylene used had a low melting point or a low yield point stress. Further, since the ethylene α-olefin copolymer was not added, the appearance was severe.

Comparative Examples 8 to 10 are similar to Examples 7 to 9 except that ethylene α-
In the case where no olefin copolymer was added, and when the elongation was 100% or less, the appearance of Comparative Example 10 was extremely rough.

This electric wire can be further cross-linked by an electric wire, a peroxide alkoxyla graft or the like. Crosslinking can further improve wear resistance and heat resistance.

[Effects of the Invention] As described above, according to the present invention, a thin-walled thin electric wire can be manufactured at a high speed, and a small-diameter insulated electric wire having excellent electrical and mechanical properties can be obtained.

[Brief description of the drawings]

 FIG. 1 is a side view of an abrasion resistance test apparatus, FIG. 2 is a side view of a withstand voltage test apparatus, and FIG. 3 is a side view of a flame retardancy test.

Continued on the front page (72) Inventor Toshiaki Ichige 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture Inside the Hidaka Plant, Hitachi, Ltd. (72) Inventor Hideo Takano 5-chome, Hidaka-cho, Hitachi City, Ibaraki Prefecture No. 1-1 Inside the Hidaka Works of Hitachi Cable Co., Ltd. (56) References JP-A-51-39744 (JP, A) JP-A-59-105040 (JP, A) JP-A-63-3043 (JP, A) JP-A-60-146407 (JP, A) Eitaro Oka and one other editor, "Plastic Materials Course 4 Polyethylene Resin" (18.8.30, 1969), Nikkan Kogyo Shimbunsha, p. 102-105 Tadahisa Ota and two other authors, "Plastic Materials Course 11 Polyethylene", 5th Edition (1405.30), Nikkan Kogyo Shimbun, p. 124-125 (58) Fields surveyed (Int. Cl. ⁶⁾ , DB name) H01B 7 / 02,7 / 34 H01B 3/44

Claims (1)

(57) [Claims] In a thin insulated wire having an outer diameter of 1 mm or less having an insulator of 200 μm or less in thickness on a conductor, polyethylene 99-85 having a yield point stress of 150 kg / cm ² or more and a melting point of 115 ° C. or more is used. Parts by weight and ethylene-α-olefin copolymer 1
A small-diameter insulated wire comprising: an insulator formed of a composition containing 10 to 30% by weight of a halogen-based flame retardant and an inorganic flame-retardant aid in total, containing up to 15 parts by weight.