JP3345966B2 - Flame retardant resin composition and insulated wire therefrom - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to superior melt extrusion processability, it relates to an insulated wire or the like therefrom and flame retardant electrically insulating resin composition having excellent mechanical properties with low dielectric constant.

[0002]

2. Description of the Related Art Polyethylene resins such as high-density polyethylene and low-density polyethylene have excellent electrical insulation properties and a low dielectric constant of 2.1 to 2.2, so that they can be used in computers, video equipment, OA equipment, wireless equipment, and the like. It is widely used as an insulator for shielded electric wires and coaxial cables that transmit weak high-frequency signals. If the conductor is extruded and covered while being foamed on the conductor, the dielectric constant of the insulator can be reduced to about 1.3 to 1.6. A shielded wire can be obtained. On the other hand, shielded wires and coaxial cables used in the above electronic devices are also required to be flame-retardant, and polyethylene insulators and foamed polyethylene insulators are flammable. In many cases, the outer periphery is coated with a flame-retardant sheath such as a polyvinyl chloride resin composition to secure the flame retardancy of the entire cable.

As a standard for evaluating the flame retardancy of a shielded electric wire or a coaxial cable, for example, the UL standard (Underwriting) is used.
ters Laboratories Inc. ), A vertical burning test (VW-1), in which the sample was placed vertically and the burner flame was set to 20 ° as shown in FIG.
When ignition was repeated 5 times at an angle of 15 seconds, 6
This is an evaluation test for flame retardancy, in which the fire is extinguished within 0 seconds, the kraft paper attached to the upper part must not be burned, and the cotton wool laid below must not be ignited by burning falling objects. Furthermore, depending on the application, there is a case where it is required that the insulator alone (with the sheath and the outer conductor removed) passes the vertical combustion test (VW-1SC). It is necessary to use, as an insulator, a polyethylene resin or its foam which has been made flame-retardant by, for example, blending a system-based flame retardant or various fillers.

[0004] However, a resin composition obtained by flame-retarding polyethylene by the above-described method has a problem in that the tensile strength and the elongation at break are remarkably reduced or the brittleness temperature is increased. There are cases where such problems occur, and there is a problem that is not practical. On the other hand, ethylene has α- such as 1-butene, 1-hexene, 1-octene and 4-methyl-1-pentene.
Olefin is copolymerized and the density is about 0.905g / c
A method using a so-called ultra-low density polyethylene in which the degree of crystallinity is controlled so as to be not more than m ³ has also been proposed.

[0005] Ultra-low-density polyethylene has the same electrical insulation and dielectric constant as high-density polyethylene and low-density polyethylene, and has excellent receptivity to various compounding agents such as flame retardants and fillers. Even if the flame retardant is increased to such an extent that it passes the vertical combustion test by blending a large amount of flame retardants and fillers, the decrease in mechanical properties such as tensile strength and elongation at break is small and brittle. There is an advantage that there is no problem such as an increase in the formation temperature. However, the resin composition obtained by flame retarding ultra-low density polyethylene has a disadvantage that the melt extrusion processability is extremely poor.For example, when extrusion coating is performed on a conductor or extrusion coating is performed while foaming is performed, the extrusion linear speed is reduced. If it is raised, the appearance tends to be rough, and there is a problem that the product cannot be efficiently manufactured at a high linear velocity.

On the other hand, ethylene copolymers such as ethylene EVA resin and EEA resin obtained by copolymerizing vinyl acetate and ethyl acrylate also because of excellent receptivity to various fillers such as flame retardants and fillers The flame-retardant resin composition has the advantage that there is little decrease in mechanical properties, and there is little problem such as rough appearance even in melt extrusion coating at a high linear velocity. However, ethylene copolymers such as EVA resin and EEA resin are compared with ultra low density polyethylene.
Since there is a defect that the dielectric constant is high, for example, in order to obtain a dielectric constant equivalent to that of the flame-retardant ultra-low density polyethylene foam insulator, it is necessary to increase the expansion ratio, so that the outer diameter of the coating is It is not preferable because there are problems such as difficulty in control and an increase in foaming ratio, such as a decrease in tensile strength of the foamed insulator and a decrease in mechanical strength. For this reason, a flame-retardant resin composition having a low dielectric constant, excellent melt-extrusion processability, and having no problem of a decrease in mechanical strength such as tensile strength even when formed into a foamed insulator. Development was desired.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on such problems and found that the density was 0.905 g / cm ^3.
The following ethylene ultra low density polyethylene - propylene rubber blend, by blending a halogen-based flame retardant such as a flame retardant resin composition with improved flame retardance to the level of the vertical flame retardancy, melt Excellent in extrusion processability, even when melt-extrusion or foam-extrusion coating on conductors, can produce high-speed, high-efficiency, low-dielectric-constant, flame-retardant insulated wires without causing problems such as rough appearance. Further, it has been found that even when the resin composition is subjected to extrusion coating while being foamed, it is possible to produce a flame-retardant foamed insulated wire having a low dielectric constant without a problem of a decrease in mechanical strength. Invented the invention.

That is, the present invention provides:On the conductor (A) Density 0.905 g / cm^ThreebelowUltra low densityPollier
Tylene and (B) ethylene-propylene rubberIs a mixture with
Therefore, the mixing ratio of (A) / (B)95/5 to 50/50so
is thereThe resin mixture is (C)Halogen flame retardantFlame retardant
ReAnd the dielectric constant is 2.7 or lessFlame retardanceFor electrical insulationTree
Fat compositionIs coated, UL standard VW-1 combustion test
Flame retardant insulated wireI will provide a. Also,  
Flammability describedFor electrical insulationThe resin composition is coated,
An outer conductor layer is formed around the outer periphery of the coating layer.UL rule
Flame retardant insulation that passes the rated VW-1 combustion testShield electric
Provide a line. Also,  Flame retardant electricity on conductor
For insulationThe foam of the resin composition is covered,
An outer conductor layer is formed on the outer periphery of the coating layer,UL standard
Flame Retardancy Passing VW-1 Combustion TestFoam shieldInsulation
Provide wires. Also,  Single or multiple core insulation
The flame-retardant electricity described on the outer circumference of the wireFor insulationThe resin composition is
Coated,Passes UL standard VW-1 combustion test
Flame retardantProvide insulated cables.

Hereinafter, the present invention will be described in detail. Of the present invention
The ultra-low density polyethylene (A) is a copolymer of ethylene with an α-olefin such as 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene , having a density of 0.9.
05 g / cm ³ or less, preferably 0.902 to 0.87
It refers to an ethylene copolymer whose crystallinity is controlled to be 0 g / cm ³ . Ethylene-propylene rubber (B) is a so-called EPDM obtained by copolymerizing a random copolymer rubber of ethylene and propylene or a diene component such as dicyclopentadiene, ethylidene norbornene or 1,4-hexadiene as a third component with ethylene and propylene. Say.

The flame-retardant resin composition for electrical insulation of the present invention comprises :
Density 0.905 g / cm ³ or less very low density polyethylene <br/> emissions (A) and ethylene - propylene rubber (B) and a melt extrusion processability of viewpoint these resin compositions flame retardant, (A) / (B)
The mixing ratio should be set to a weight ratio range of 95 / 5-50 / 50.

[0011] Ultra-low-density polyethylene (A) and the ethylene - The mixture <br/> flame retardant for flame retardancy of propylene rubber (B), polybrominated diphenyl ethers, brominated bisphenol derivatives, brominated ethylenebis phthalimide, bis (brominated phenyl) ethane, bis (brominated phenyl) terephthalamide compounds, perchlorethylene penta tricyclodecane, bromine, such as chlorinated paraffins, and a halogen-based flame retardant of chlorine, such as . Further, metal hydroxide-based flame retardants such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; phosphorus-based flame retardants such as trioctyl phosphate; antimony trioxide, antimony pentoxide, molybdenum oxide, silica, Metal oxides such as clay, talc and zinc white; metal carbonates such as basic magnesium carbonate and calcium carbonate; metal borates such as zinc borate and barium metaborate can also be used.

The flame-retardant resin composition for electrical insulation of the present invention is mixed with an open roll mixer, a Banbury mixer,
It is possible to mix with a known mixing device such as a pressure kneader, a Henschel mixer, a twin-screw mixer and the like. In the resin composition, various compounding chemicals such as an antioxidant and a processing stabilizer, a lubricant, a coloring agent, a plasticizer, a polyfunctional monomer, and a vulcanizing agent can be compounded as necessary. If the resin composition is coated on the conductor by using the insulated wire, a flame-retardant insulated wire having a high linear velocity and a low dielectric constant can be obtained efficiently. In particular, polyfunctional monomers such as trimethylolpropane trimethacrylate and triallyl (iso) cyanurate can be used as crosslinking accelerators. In addition, a chemical foaming agent such as azodicarbonamide, p, p'-oxybis (benzenesulfonylhydrazide), or p-toluenesulfonylsemicarbazide is preliminarily blended with the resin composition and foamed and extruded to provide a lower dielectric constant. Since flame-retardant foamed insulated wires can be obtained, VW
Shielded wires and coaxial cables requiring -1SC can be manufactured.

After extrusion coating or foam extrusion coating, if the coating layer is cross-linked by irradiating ionizing radiation such as an accelerated electron beam or gamma ray, an insulator or a foamed insulator having excellent heat deformation resistance can be obtained. Can also. In place of the electron beam crosslinking, a crosslinking agent such as dicumyl peroxide may be previously blended in the base material and then subjected to so-called chemical crosslinking by heating. Also, LAN, such as in Figure 2 the resin composition
UTP cable (UTP: Unshielded)
If applied as a sheath material of Twist Pair, a UTP cable having a small transmission loss between twisted pairs can be manufactured. The shield layer constituting the shielded electric wire is not particularly limited as long as it can constitute a shield layer such as a horizontal conductor layer, a braided conductor layer, a metal foil provided with an adhesive layer, or a metal filler-containing adhesive resin layer.

[0014]

The present invention will be described in more detail with reference to the following examples, which do not limit the scope of the present invention. The resin compositions shown in Tables 1 and 2 were kneaded with an open roll mixer heated to 120 to 140 ° C. and pelletized. The resin compositions shown in Tables 1 and 2 contained 0.5 parts by weight of stearic acid, 50 parts by weight of decabromodiphenyl ether, 20 parts by weight of antimony trioxide, 10 parts by weight of basic magnesium carbonate, and 10 parts by weight of dry silica. Part, pentaerythrityltetrakis [3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate] 1
Parts by weight were blended in common. The pellets of the resin composition obtained by the above method were melt extruded (30 mmφ, L / D = 24,
Using a full flight screw with a compression ratio of 2.5), the thickness is 0.4 m on a tin-plated soft copper conductor with an outer diameter of 0.8 mmφ
m, and extrusion extrusion coating or foam extrusion coating was performed, and the extrusion linear velocity was set to two conditions of 50 m / min and 300 m / min, and the appearance of the extrusion coating layer was examined. After irradiating 100 kGy of the insulated wire manufactured by the above method with an electron beam having an acceleration voltage of 2 MV, the insulated wire manufactured at an extrusion wire speed of 300 m / min.
Insulator tensile strength, elongation at break, dielectric constant (measurement conditions: 1M
Hz) was measured at n = 3, and the flame retardancy of the insulated wire was examined at n = 3 by a vertical combustion test (VW-1 method).

(Examples 1, 2, 5) In Examples 1, 2, and 5, the ultra-low density polyethylene having a density of 0.905 or less and ethylene-propylene rubber were 95/5 to 5/5.
A mixture mixed in a weight ratio range of 60/40 was mixed with the above formulation.
By an insulating wire using the resin composition flame retardant,
The extruded appearance is good at both linear speeds of 50 m / min and 300 m / min, has a low dielectric constant of 2.7 or less, has passed the vertical combustion test, and has a tensile strength of 1.0 kg / mm ² or more and is mechanical. It turns out that it is also excellent in physical properties.

(Examples 3 and 4) In Examples 3 and 4, ultra-low density polyethylene having a density of 0.905 or less and ethylene-propylene rubber were 95/5 to 60.
In the formulation of the / 40 mixture was mixed in a weight ratio range of
Ri and flame retardant, a resin composition obtained by kneading azobis carbonamide foaming agent, in an extrusion line speed of 300 meters / min, while performing condition setting an extruder die temperature in the range of 180 to 200 ° C., was foamed extrusion foaming Insulated wire, good appearance, low dielectric constant of 1.5 to 1.6, passed vertical combustion test, tensile strength of 1.0 kg / mm ² or more, and excellent mechanical properties You can see that

Example 6 In Example 6, an ultra-low density polyethylene having a density of 0.905 or less and an ethylene-propylene rubber were mixed at a ratio of 50/50.
It is an insulated wire using a resin composition in which the mixture is made flame-retardant by the above-mentioned formulation. The appearance is slightly poor at an extrusion linear speed of 300 m / min, but is good at an extrusion linear speed of 50 m / min, and the dielectric constant is 2 .7, and passed the vertical combustion test, and had excellent mechanical properties and excellent flexibility.

[0018]

[Table 1] (* 1) ML _{1 + 4} (100 ° C): 55, ethylene ratio 6
5%, iodine value: 10 (* 2) ML _{1 + 4} (100 ° C.): 43, ethylene ratio 5
5%, iodine value: 12

(Comparative Examples 1 to 3) Comparative Examples 1 to 3 use a resin composition in which a very low-density polyethylene having a density of 0.905 or less is made flame-retardant by the above formulation . At the extrusion linear speed of 50 m / min, poor appearance has already occurred. (Comparative Example 4) In Comparative Example 4, a low-density polyethylene having a density of 0.918 was used .
It is a resin composition which has been made flame-retardant by the above prescription. The appearance is good at an extrusion linear speed of 50 m / min, but the elongation of the insulator is less than 100%, which is insufficient as an insulated wire. . (Comparative Example 5) In Comparative Example 5, a high-density polyethylene having a density of 0.935 was used .
The resin composition was made flame-retardant by the above-mentioned prescription , and caused poor appearance at an extrusion linear speed of 50 m / min.

[0020]

[Table 2]

Comparative Example 6 Comparative Example 6 is a mixture of ultra low density polyethylene having a density of 0.905 or less and ethylene-propylene rubber mixed at a ratio of 40/60.
It uses a resin composition obtained by making the mixture flame-retardant by the above-mentioned formulation , and has a problem of causing poor appearance at an extrusion linear speed of 50 m / min. (Comparative Example 7) Comparative Example 7 is a mixture of ultra low density polyethylene having a density of 0.905 or less and ethylene-propylene rubber mixed at a ratio of 30/70.
It uses a resin composition obtained by making the mixture flame-retardant by the above-mentioned formulation , and has a problem of causing poor appearance at an extrusion linear speed of 50 m / min.

[0022] (Comparative Examples 8 and 9) Comparative Examples 8 and 9 are very low density of density 0.905 or less polyethylene <br/> styrene and vinyl content acetate 15% ethylene - vinyl acetate copolymer 80 / This is a resin composition in which a mixture mixed at 20, 50/50 is made flame-retardant by the above-mentioned formulation , and there is a problem that poor appearance occurs at an extrusion linear speed of 50 m / min. (Comparative Example 10) Comparative Example 10 uses a resin composition in which the ethylene-vinyl acetate copolymer used in Comparative Examples 8 and 9 is made flame-retardant by the above-described formulation alone, and has an extrusion linear speed of 300 m / min. However, it has good appearance, excellent mechanical properties, and has passed the vertical combustion test and the low-temperature winding test, but has a dielectric constant of 3.6, which is considerably higher than those of Examples 1 to 6.

(Comparative Example 11) In Comparative Example 11, an ultra-low density polyethylene having a density of 0.905 or less and an ethylene-ethyl acrylate copolymer having an ethyl acrylate content of 25% were mixed at a ratio of 50/50. above the mixture
The resin composition was made flame-retardant by the above-mentioned prescription , and caused poor appearance at an extrusion linear speed of 50 m / min. (Comparative Example 12) Comparative Example 12, ethylene was used in Comparative Example 11 - are those using the resin composition flame-retardant by the formulation alone ethyl acrylate copolymer, extrusion linear speed 300 meters / min However, it has good appearance, excellent mechanical properties, has passed the vertical combustion test and the low-temperature winding test, and has excellent flexibility, but has a dielectric constant of 4.0, which is higher than that of Comparative Example 10. .

[0024]

[Table 3]

(* 1) ML _{1 + 4} (100 ° C.): 55, ethylene ratio 6
5%, iodine value: 10 (* 2) ML _{1 + 4} (100 ° C.): 43, ethylene ratio 5
5%, iodine value: 12 (* 3) Vinyl acetate content: 15%, melt flow rate: 2 (190 ° C., 2160 g) (* 4) Ethyl acrylate content: 25%, melt flow rate: 5 (190 ° C., 2160 g)

[0026] (Comparative Example 13) Comparative Example 13, ethylene was used in Comparative Example 10 - composition elemental vinyl acetate copolymer were kneaded azobis carbonamido blowing agent to that flame retardant by the formulation Using an extrusion linear speed of 300 m / min and an extrusion die temperature of 170 to
Foam extrusion coating was performed at a temperature in the range of 200 ° C. Under foam extrusion conditions in which the appearance is good and the outer diameter is stable, the dielectric constant is 2.4, which is considerably higher than Examples 3 to 4, and the tensile strength is less than 1.0 kg / mm ² , If extrusion conditions were set to further increase the expansion ratio in order to lower the dielectric constant, stable extrusion was difficult. (Comparative Example 14) In Comparative Example 14 , the ethylene- acrylic acid used in Comparative Example 12 was used.
Using a resin composition obtained by kneading an azobiscarbonamide foaming agent into a flame-retardant single substance of an ethyl luate copolymer according to the above-mentioned formulation , an extrusion linear speed of 300 m / min and an extruder die temperature of 170 to 200 ° C. Foam extrusion coating was performed under the conditions of Under foam extrusion conditions in which the appearance is good and the outer diameter is stable, the dielectric constant is 2.7, which is considerably higher than that of Examples 3 to 4, and the tensile strength is less than 1.0 kg / mm ² . If extrusion conditions were set to further increase the expansion ratio in order to lower the dielectric constant, stable extrusion was difficult.

[0027]

[Table 4]

As described above, the density of Examples 1 to 6 is 0.
Ultra low density polyethylene (A) of 905 (g / cm ³ ) or less
And the mixing ratio of ethylene-propylene rubber (B) is 95/5
The use of a resin composition obtained by flame-retarding a resin mixture obtained by mixing a resin mixture having a weight ratio of about 50/50 with a halogen-based flame retardant (C) provides a good extruded appearance at a high linear velocity, a low dielectric constant, and a flame retardancy. An insulated wire having excellent mechanical properties can be obtained. Further, if a foaming agent such as azobiscarbonamide is kneaded in advance with the resin composition and foamed and extruded, a foamed insulated wire having a low dielectric constant, excellent flame retardancy, and no problem of a decrease in tensile strength can be obtained. Can be

On the other hand, the density is 0.905 (g / cm
Halogen ³⁾ following ultra low density polyethylene (A) alone
With a resin composition flame-retarded by the flame retardant (C) , an insulated wire with good extruded appearance cannot be obtained. In addition, 0.905 (g
/ Cm ³ ) A resin composition obtained by flame retarding a mixture of an ultra low density polyethylene (A) of not more than (A) and an ethylene-vinyl acetate copolymer or an ethylene-ethyl acrylate copolymer with a halogen-based flame retardant (C) . Does not provide an insulated wire with good extrusion appearance.

The ethylene-vinyl acetate copolymer or the ethylene-ethyl acrylate copolymer may be used alone as a halogen-based copolymer.
With the resin composition flame-retarded by the flame retardant (C) , an insulated wire with good extruded appearance can be obtained.However, there is a problem that the dielectric constant becomes high. Under the conditions where foam extrusion can be performed, there is a problem that the dielectric constant increases and the tensile strength is less than 1.0 kg / mm ² , resulting in insufficient mechanical strength.

Example 7 A pellet of the resin composition of Example 1 was melt extruded (30 m).
mφ, L / D = 24, full flight screw, compression ratio 2.5), and the linear velocity so that the thickness becomes 0.3 mm on the seven-stranded conductor of the tin-plated soft copper conductor having an outer diameter of 0.127 mmφ. After extrusion-coating at 300 m / min to form an insulator, an electron beam at an acceleration voltage of 2 MV was irradiated at 100 kGy.
A horizontally wound shield layer is formed of a tin-plated soft copper conductor having a strand diameter of 0.12 mmφ on the outer periphery of the insulated wire, and a soft PVC composition (Sumiflex K600SN-
16. Sumitomo Bakelite Co., Ltd .;
Extrusion coating was performed at 0 mm to produce a shielded electric wire. The tensile strength of the insulator of this shielded wire is 1.5 kg / mm ² ,
The elongation is 538%, which is excellent in mechanical strength, and the capacitance is 160
At pF / m (1 MHz), passed the vertical combustion test (VW-1), peeled off the soft PVC coating layer and the horizontal shield layer,
The shielded wire was excellent in flame retardancy and passed the vertical combustion test (VW-1SC) using only the insulator.

(Comparative Example 15) The resin composition of Comparative Example 10 was used as the resin composition of the insulator, and the thickness became 0.3 mm on the seven-stranded conductor of the tin-plated soft copper conductor having an outer diameter of 0.127 mmφ. As linear speed 300
After extrusion coating at m / min to form an insulator, an accelerating voltage of 2
An electron beam of MV was irradiated at 100 kGy. On the outer periphery of this insulated wire, the same structure as that of the seventh embodiment and
A C composition coating layer was formed to produce a shielded electric wire. The tensile strength of the insulator of this shielded wire is 1.3 kg / mm
^2. Elongation is 623%, which is excellent in mechanical strength, passed the vertical combustion test (VW-1), peeled off the soft PVC coating layer and the horizontal shield layer, and performed the vertical combustion test (VW-1) using the insulator alone.
Although it was excellent in flame retardance that passed SC), the capacitance was 218 pF / m (1 MHz), and there was a defect that the capacitance was larger than that of the shielded wire of Example 7.

Example 8 A resin extruder (30 mm) of the resin composition of Example 3 was placed on a seven-stranded conductor of tin-plated soft copper conductor having an outer diameter of 0.127 mmφ.
φ, L / D = 24, full flight screw, compression ratio 2.5), die temperature 188 ° C., extrusion linear speed 3
When the foaming extrusion was performed so that the thickness was 0.3 mm and the capacitance was 90 pF / m at a setting of 00 m / min, it was possible to form a foamed insulating layer with good appearance. After irradiating this foamed insulated wire with an electron beam having an acceleration voltage of 2 MV at 100 kGy, a horizontal winding shield layer and a soft PVC composition coating layer were formed on the outer periphery in the same configuration as in Example 7 to manufacture a shielded wire. This shielded wire passed the vertical combustion test (VW-1), and the foamed insulator had a tensile strength of 1.0 kg / mm ² ,
It has excellent elongation of 278% and excellent mechanical strength.
The coating layer and the horizontal shield layer were peeled off, and the shielded wire was low in capacitance and excellent in flame retardance, and passed the vertical combustion test (VW-1SC) using the foamed insulator alone.

(Comparative Example 16) The resin composition of Comparative Example 13 was used as the resin composition of the foamed insulator, and the melt extruder (30 mmφ, L / D = 24, full flight screw, compression ratio 2.5) was used. Using, while setting the die temperature in the range of 170 ~ 200 ℃,
The thickness is 0.3 mm and the capacitance is 95 pF / m on a seven-strand conductor of tin-plated soft copper conductor with an outer diameter of 0.127 mmφ.
(1 MHz), the foamed extrusion was attempted to form a foamed insulating layer. As a result, the outer diameter of the foamed insulator was significantly fluctuated and the appearance was roughened, and stable production was not possible.

(Embodiment 9) Sumikasen E104 was placed on a soft copper wire having an outer diameter of 0.51 mmφ.
(Low-density polyethylene, Sumitomo Chemical Co., Ltd .; trade name)
A pellet of a material obtained by mixing 1 part by weight of azobiscarbonamide with respect to 100 parts by weight was melt extruded (30 mmφ,
L / D = 24, full flight screw, compression ratio 2.
Using 5), the die temperature is set to 190 ° C., and foam extrusion is performed so that the extrusion outer diameter becomes 0.87 mmφ.
A foam insulated wire having a capacitance of 203 pF / m was obtained. This foam insulated wire was twisted at a pitch of 15 mm to form a twisted pair. Four twisted pairs are assembled, and the pellet of Example 2 is melt-extruded (50 mmφ, L /
D = 24, full flight screw, compression ratio 2.5), and extruded at a linear velocity of 50 m / min so as to have an outer diameter of 6.0 mmφ and a wall thickness of 0.7 mm.
A TP cable was manufactured. When the transmission loss of the twisted pair of this UTP cable was measured at 100 MHz,
The transmission loss per 00 m length was 18 dB, and this cable passed the vertical combustion test (VW-1), was excellent in flame retardancy, and was found to exhibit sufficient characteristics as a UTP cable.

(Comparative Example 17) A flexible PVC composition (Sumiflex K600) was formed on the outer periphery of a set of four twisted pairs produced in Example 9.
SN-16, Sumitomo Bakelite Co., Ltd .; trade name) is extrusion-coated so as to have an outer diameter of 6.0 mmφ and a wall thickness of 0.7 mm to form a sheath layer, and UTP (Unshielded).
d Twist Pair) cable was manufactured. When the transmission loss of the twisted pair of this cable was measured at 100 MHz, the transmission loss per 100 m length was 24 dB.
Thus, it was found that the transmission loss was larger than that of the cable of Example 9 and there was a practical problem.

[0037]

As described above, according to the present invention,
A flame-retardant resin composition with excellent extrudability, low dielectric constant, and excellent mechanical properties can be obtained, so it is possible to obtain flame-retardant insulated wires for signal transmission, insulators for flame-retardant shielded wires, and sheaths for LAN UTP cables. It can be applied as a material and has a very large value in the electric and electronic fields.

[Brief description of the drawings]

FIG. 1 is a schematic partial perspective view of a UL standard vertical combustion test (VW-1) apparatus.

FIG. 2 shows a cross section of a UTP cable using the resin composition of the present invention as an insulator.

[Explanation of symbols]

 Reference Signs List 1 sheath 2 conductor 3 insulator 4 twisted pair 14 chamber 15 burner 16 kraft paper 17 absorbent cotton 18 sample

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-210151 (JP, A) JP-A-59-3815 (JP, A) JP-A-63-72734 (JP, A) JP-A-2- 53833 (JP, A) JP-A-4-125122 (JP, A) JP-A-63-196521 (JP, U) JP-A-63-37029 (JP, U) JP-A-1-64422 (JP, U) 63-163933 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 23/00-23/36 C08K 3/00-13/08 H01B 3/44

Claims (4)

(57) [Claims] 1. The method according to claim 1 , wherein the (A) density is 0.905 g / cm on the conductor.
³ following ultra-low density polyethylene and (B) an ethylene - a mixture of propylene rubber, (A) / (B) resin mixture (C) halogen mixing ratio is 95 / 5-50 / 50
Flame retardant with a dielectric flame retardant of 2.7 or less
U-coated with a flame-retardant resin composition for electrical insulation
A flame-retardant insulated wire that passes the LW VW-1 combustion test . Wherein is flame-retardant electrical insulating resin composition according to claim 1, wherein is coated, to pass the VW-1 flame test of UL Standard that has the outer conductor layer is formed on the outer periphery of the coating layer
Flame-resistant insulated shielded wire. 3. The flame-retardant electrical insulation of claim 1 on a conductor.
UL foam V coated with a foam of a resin composition for use, and an outer conductor layer formed on the outer periphery of the foam coating layer.
Flame-retardant foam shielded insulated wire that passes the W-1 combustion test . 4. A flame-retardant electric insulation resin composition according to claim 1 coated on the outer periphery of a single-core or multi-core insulated wire, which is difficult to pass the UL standard VW-1 combustion test.
Flammable insulated cable.