DE2117247A1 - Insulated cable - Google Patents

Description

Dipl.-Ing. F.Weickmann, Dr. Ing, A.Weickmann, Dipl.-Ing. H.Weickmann Dipl.-Phys. Dr. K. Fincke patent attorneys

8 MUNICH 27, MÖMLSTRASSE 23, CALL NUMBER 483921/22 ^ 1 1 * 7? A 7

Case 79 Ref. 55.502
Hn / Cl

Sumitomo Electric Industries Ltd., 15, 5-chome, Kitahama, Higashi-ku, Osaka / Japan

Insulated cable

The invention relates to an insulated cable with an outer semiconducting layer; it relates in particular to the construction of an insulated cable, which consists mainly of a crosslinked polyethylene or a crosslinked polyethylene copolymer with an outer semiconducting layer. The composition is a mixture of 10 to 90 weight £ of an ethylene-vinyl acetate copolymer containing 15 to 55 parts by weight vinyl acetate content 5S and 90 to 10 wt -.% Of an ethylene / vinyl acetate / vinyl chloride terpolymer, which is used as a base material and which is treated with a crosslinking agent and a conductive agent, such as. B. soot, is mixed. So far, to cover the insulating layer of a cable insulated with a cross-linked Polyä% len with

BATH ORIGINAL. 109844 / 1-6 03

an extruded semiconducting layer, the base material being "a low-density polyethylene, an ethylene / vinyl acetate mixture polymer or a polymer composed mainly of these substances was used, the also talc, clay, calcium carbonate or similar inorganic fillers, also various antioxidants, Processing aids, if necessary, and the like, were added, usually a composition such as z. B. a mixture of an ethylene / vinyl acetate copolymer, Di-o-cumyl peroxide or similar crosslinking agents and electrically conductive carbon black or a mixture of one Ethylene / ethyl acrylate copolymer, di-a-cumyl peroxide or similar crosslinking agents and electrically conductive carbon black are used. When splicing and treating the end of one with crosslinked polyethylene insulated cable with an outer semiconducting layer must be the semiconducting layer in the Area of the end of the cable to be stripped from it to a certain length and in this case the semiconducting layer must be completely removed, and if it care must be taken not to damage the isolator. In addition, in the last few years a method of splicing and forming the termination of the cable using preformed accessories Developed for the production of the connection and terminal equipment of the cable insulated with cross-linked polyethylene the outer semiconducting layer, which has the advantage that it is possible to obtain a product of a more uniform quality manufacture and handle the cable in less time than a conventional method in which a Strip wrapped around and thermoforming performed has been, creating a trend towards generalization

8AD ORIGINAL

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. f

SM 17247

such a procedure arose. In this case there is a growing need for the semiconducting layer to be peeled off (stripped) in a shorter time and more easily can be so that the insulator is not damaged because the preformed accessories and the cable mated without causing any electrical faults.

If the described, commonly used compositions were extruded onto the insulator »in order to coat it with it, it was not only very difficult and required Not only was there a lot of time, but there was also a risk that the insulator would break when the applied compositions were peeled off damaged by the cable. For this reason, such compositions do not meet the requirements described above.

In contrast, recently there has been proposed a cable insulated with a crosslinked polyethylene having a semiconductive layer which can be stripped easily and effectively without leaving any part of the semiconducting layer on the insulator and without damaging the insulator. This proposal relates to a cable insulated with a cross-linked polyethylene with a semiconducting layer, with which the insulator is coated by extrusion coating and a cable is obtained which has the property that it easily strips the semiconducting layer from the cable by itself and that characterized in that the semiconducting layer with a composition of a mixture of 2,5-dimethyl-2 ¹ , 5'-dKtert.-butylperoxyJhexin ^ and an ethylene / vinyl acetate copolymer with a vinyl acetate content of 25 to 55 wt. Z, preferably in a ratio of 0.3

10986Λ / Ϊ603

up to 5.0 parts by weight of the former per 100 parts by weight of the last-mentioned copolymer extrusion-coated will. However, this proposal has the disadvantage that the strippability strength exceeds a certain value cannot be reduced.

The object of the present invention is to provide an excellent insulated cable, in particular an insulated cable with a easily strippable, semiconducting layer to get that made of a cross-linked polyethylene or a cross-linked polyethylene copolymer as the main ingredient.

In the following the invention in connection with the accompanying drawing, in which an embodiment of the invention is shown in more detail.

Strippable strength was investigated in order to eliminate the disadvantages of the type described above, which led to success in obtaining a crosslinked polyethylene cable having an improved semiconductor layer which can be easily stripped off. The invention is now characterized in that it is in the conductive layer is a composition of a mixture of 90 to 10 wt -.% Of a Äthyl.r / vinyl acetate copolymer containing 15 to 55 wt .- ^ vinyl acetate and 10 to 90 Ge \ i .-% of an ethylene / vinyl acetate / vinyl chloride terpolymer with a common crosslinking agent, such as. B. dicumyl peroxide or 2,5-dimethyl-2 ', 5'-di (tert-butylperoxy) -hexyne-3, preferably in a ratio of 0.3 to 50 parts by weight of the latter to 100 parts by weight of the first-mentioned copolymer or terpolymer.

109844M603

Because the composition is made into a semiconducting layer of course, it is only necessary to mix in an appropriate amount of carbon black to make the composition conductive make, as well as other agents such as antioxidants, processing aids, etc., as appropriate, as appropriate the conditions of use.

The test results obtained have shown that the amount of carbon black (25 to 70 parts by weight compared to 100 parts by weight of polymer) and on antioxidants based on amine or Ph en o 1 * - and on processing aids, such as. B. zinc stearate, do not affect the tendency of the composition to be easily stripped off.

The following is an embodiment of the invention in an insulated cable with an outer semiconducting layer underneath Described with reference to the accompanying drawing. The number 1 means a <n conductor, the number 2 an inner one semiconducting layer, the number 3 an insulating layer and the number 4 is an outer semiconducting layer.

Examples and reference examples are given below. The materials used in the examples and the experimental Procedures were as follows:

An ordinary inner semiconducting layer was applied to a conductor from a twisted cable with a cross section of

100 mm extruded so that the conductor was covered with it and the cable conductor coated in this way was then extrusion-coated with the insulating layer and the semiconducting layer Layer as indicated in the following Table I, further coated and the layer was in saturated water

BAD ORJGfNAL 109844 / ^ 603

Steam of 15 atmospheres is subjected to a killing reaction. By making a cut 10 mm wide, in the axial direction in the semiconducting On the layer covering the surface of the conductor, an adhesion test (adhesion test) was carried out. the The results obtained are shown in Table I below.

In the semiconducting layer in the table below, 50 parts by weight of acetylene black and 1 part by weight of antioxidant were used and 1 part by weight of zinc stearate with 100 parts by weight of the base polymer (including, of course, mixtures of different polymers) mixed and the crosslinking agent was in terms of type and amount as well as the thickness of the semiconducting layer varies. .

Isolated
layer Table I. Network
with
tel r (above the • Peel strength
capacity (kg / 10mm) No. "* Semiconducting layer
Insulator) 1 X +) - 2 thickness
(mm) Cover polyethy-
clasp
game 1 Basic po
lymeri
sat 1 % 0.5 more than 5 E.VA +) - something stayed up
the isolator
return Vinyl-
= 15 % / MI = 6 \ Specifi
sches Ge
weight =
042 g /
cnr DCP = 2, -52
Antioxidant = 0.33! +) '- 3 MI = 2

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No. Insulated layer Semiconducting layer (via peel-off

the isolator) _ activity

(kg / 10 mm)

Basic poly- Vemet- thickness merization (mm) middle

Reference and reference example 1 game 2

E. VA

Vinyl acetate = 2556

M I s 6

X + J -

1%

0.5

3.9

Reference at
game 3

Reference at
game H

E. VA

Vinyl acetate = 35 %

HI = 6

E * VA

Vinyl acetate = 505 "

M I a 6

3.5

example

E.VA

Vinyl acetate = 10Ji

M I = 6 +> 5

plus SUMI-GRAFT 105S

"more than 5,

Example 2 "Reference example 1 + SUMIGRAFT 10 %

3.0

Example 3 "Reference example 2 + SUMIGRAFT 10 %

2.8

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21172 ί 7

Insulated layer Semiconducting layer '(via peelable

Isolator). activity

like reference
game 1 Basic poly
merisat Ve rne t -
tongue
middle thickness
(mm) (kg / 10 mm) Example 4 ti Reference amount
game 3
+ SUMIGRAFT
10 % X +) - 2
1 % 0.5 1.3 Example 5 Il Reference
game 2
+ SUMIGRAFT
50 % X
1 % It 2.0 Example 6 Il Reference
game 2 + '
SUMIGRAFT
90 % Il ti 0.5 Reference at
game 5 ti SUMIGRAFT
100 % It It 0 Reference at
game 6 like reference
example 3 - It the semi
senior

Layer was cut in and not stripped off

Reference at
game 7 It It X
0.2 % It ti Reference at
game 8 It ti X
Q, 3 % It 3.5 Reference.
game 9 dd . π X
0.5 % dd •
Il Reference at
game 10 Il Il X
1.0 % ti 3.5

10984W.16Q3

No.

Insulated layer Semiconducting layer (via peel-off

the isolator) activity

(kg / 10 mm)

Basic poly- cross-linked thickness merization (mm) middle

_Rp7 , _{] (rq} . As for reference-O _n -Jp ₁ T λ

example ^{splel 2} 11

Reference at
game 1

like reference X
example 3 5.0

0.5

3.0

Reference
at
game 12 fl It X
6.0 % ti 0.3 at
game 7 Il as in-
■ game 3 X
"0.3 % It 2.7 at
game 8 Il It X
5.0 % Il 2.0 Reference
at
game 13 Il Il X
6.0 % It 0.,

like reference X 0.1

example 3 1.5 %

the semiconducting layer _β was incised and not stripped off

Reference
at
game 15 Il ti Il 0.2 3.3 Reference
at
game 16 Il Il Il 0.5 3.4 Reference
at
game 17 Il If Il 1.0 3.3

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- ίο -

No.

Insulated layer Semiconducting layer (via peel-off

dem_I s o_l ator) f e s t ig -

4th
like reference _ Basic poly Network thickness speed game 1 merisat tion (mm) (kg / 10mm) middle as in X 0.1 Reference at game 3 1.5 % the semi game 18 Ie it end layer was a cut and not stripped

Example 9 I! 11 Il 0.2 2.7 Example 10 it Il Il 0.5 2.6 Example 11 It Il Il 1.0 2.7

Reference at- Specific weight as reference X game 19 weight of the poly- example 3 2.0 % ethylene = 0.92 g /

0.7

MI = H
DCP = 2.5 %
Antioxidant = 0.5 55

Reference amounts to 30 parts by weight of talc 20 v / earth to 100 parts by weight added to the composition of Reference Example 19

X
2.0 %

0.7

3.0

Reference parts - 30 parts by weight of clay, game 21 become 100 pieces

Share the • composition of the

Reference example 19

admitted

3.1

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- li -

No. Insulated layer Semiconducting layer (via peel-off

the insulator)

"speed

Basic poly- network thickness (kg / 10mm) merization (mm)
middle

Reference example 22

EVA

Vinyl acetate = 15 %

MI = 3
DCP = 2 % aging resistance = 0.5 %

like reference X 1.0
example 3 1.5 %

Reference example 23

30 parts by weight of talc is added to 100 parts by weight of the composition of the reference example 22 added

3.9

example 12th like reference
game 19 as in
game 3 X
2.0 % 0.7 2, 7 · example 13th like reference
example, 20 Il It Il 2, 3 example 14th like reference
example 21 It Il ti 2, example 15th like reference
example 22 ti X
1.5 % 1.0 3, 6th

Example 16 as reference example 23

3.2

Reference example and reference game 24 example 1

like reference DCP 0.5
example 3 1.0 %

more than 5 * something remained on the insulator return

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No.

Insulated layer Semiconducting layer (via peel-off

strengthen the isolator

» Basic poly
merisat Network
tion
middle thickness
(mm) speed
(kg / 10mm) Reference as reference
example game 1
25th like reference -
example 3 DCP
5.0 % 0.5 more than 5,
something stayed
on the
insulator
return Reference "
example
26th EVA in Be
Zugsbei
game 3
was ge
changes to
+) -6
DPD - 6169 X
1.0 % dd

example
17th U as in
game 3 DCP
1.0 % π 2, a- example
18th Il If. DCP
5.0 % 2.0

Reference example 27

EVA in example 3 was changed to 1.0 % in DPD-6169

more than

+] - 1 EVA * ethylene / vinyl acetate copolymer

Vinyl acetate = the amount of vinyl acetate in the copolymer

+) - 2 X = 2,5-dimethyl-2 ^f , 5'-di- <tert-butylperoxy) -hexyne-3 + J-MI = 'melt flow index (g / 10 min.) (ASTM D 1238), +} - DCP = Dl-a-cumyl peroxide

1098U / t603

+) - 5 SUMIGRAFT = an ethylene / vinyl acetate / vinyl chloride ter-

polymer from Sumitomo Chemicals Manufacturing Company, Japan

+) - 6 DPD-6169, '= an ethylene / ethyl acrylate blend polymer

of the UCC, USA.

In the previous application it was possible to achieve an intentionally easily and completely strippable, semiconducting layer only if 2,5-dimethyl-2 *, 5'-di (tert-butyl-, peroxy) -hexyne-3 was used an ethylene / vinyl acetate copolymer with 25 to 55 wt -.% vinyl acetate content was mixed, the above examples show, however, that it is possible, even with the use of not only 2,5-dimethyl-2 ', 5'-di - (tert-butylperoxy) -hexyne-3, but also a common crosslinking agent, such as. B-. Di-a-cumyl peroxide, if only one ethylene / vinyl acetate / vinyl chloride terpolymer is mixed with an ethylene / vinyl acetate copolymer with a vinyl acetate content of 15-55 parts by weight, an intended, easily and completely strippable semiconducting layer is also achieved the strippability strength is essential. to belittle. If an ethylene / vinyl acetate copolymer has less than 15 % vinyl acetate content, the ethylene / vinyl acetate / vinyl chloride terpolymer is deprived of its effect and the layer produced from it is difficult to peel off and if the copolymer exceeds 55% , its adhesion is reduced too much, so that it is no longer suitable for use in a cable.

Accordingly, SUMIGRAFT is only effective and shows improved ease of strippability when the vinyl acetate content is 15 to 55 % . If the content of 2,5-dimethyl-2 ^f , 5'-dl- (tert-butylperoxy) -hexyne-3 is less than 0.3 part by weight per 100 parts by weight of the copolymer and terpolymer mixture

BAD ORIGINAL 109844 / 1-603

is, the semiconductive layer vielst a relatively low strength, and when the content is 5 wt -.% exceeds, their adhesion to the insulator to poor, so that it is no longer suitable for use in a cable. When it is within the range of 0.3 to 5 parts by weight, it shows a particularly good result. With respect to the thickness of the layer should be noted that this should be preferably more than 0.2 mm, since a layer to be a thickness of less than 0.2 mm, the inclination has torn during stripping W.

As described above, it is only possible to obtain an easily and completely strippable (peelable) semiconducting layer if the ethylene / vinyl acetate copolymer has a vinyl acetate content of 15 to 55 % and the ethylene / vinyl acetate / vinyl chloride terpolymer to the copolymer is added and the 2,5-dimethyl-2 ', 5 ¹ -di- (tert-butylperoxy) -hexyne-3 or the DCP (di-a-eumyl peroxide) preferably in a ratio of 0.3 to 5 , 0 parts by weight per 100 parts by weight of the copolymer and terpolymer mixture is present. Experiments have shown that when other types of crosslinking agents are used, no semiconducting layer of the desired quality is formed «

If the ethylene / vinyl acetate / vinyl chloride terpolymer less than 10 wt. the amount of copolymer and Terpolymer mix, it has no effect and if it is more than 90% by weight, it may not be as required Provide peel strength. On the other hand, it is clear that even if the ethylene / vinyl acetate / vinyl chloride terpolymer to another high molecular weight (polymer or) mixed polymer than an ethylene / vinyl acetate mixed poly-

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rnerisat is added and even if 2,5-dimethyl-2 ·, 5 ^! - di- (tert, -butylperoxy) -hexyne-3 or DCP is used as a crosslinking agent, no good result can be obtained. Only the use of the composition of the invention provides a semiconducting layer with excellent strippability.

It is of course clear that regardless of the size of the cable and the intended use, the invention can also be used in a cable whose insulated layer consists of a crosslinked polymer or a crosslinked Polyethylene copolymer is the main component.

109844 / 1-603

BATH ORIGINAL

Claims (1)

- 16 - Claims 1. Insulated cable with a semiconducting layer that was applied as a coating over an insulator by extrusion and consists of a crosslinked polyethylene and / or a polyethylene copolymer as the main component, which has an easily strippable * outer semiconducting layer, characterized 'that the outer semiconducting layer of the cable from a composition which has been to coat the insulator extruded onto these and a mixture of 90 to 10 wt -.% of a Äthyler / - ■ vinyl acetate / vinyl chloride terpolymer and 10 to 90 parts by JS of an ethylene / Vinyl acetate copolymer with 15 to 55 wt. 2. Insulated cable according to claim 1, characterized in that di-a-cumyl peroxide is used as the crosslinking agent of the semiconducting layer (DCP) is used. 3. Insulated cable according to claim 1, characterized in that 2,5-dimethyl-2 ^f , 5'-di- (tert-butylperoxy) hexyne-3 is used as the crosslinking agent of the semiconducting layer. * l. Insulated cable according to claims j / bls 3, thereby marked ' draws that the insulating layer consists of a cross-linked polyethylene. BAD ORIGINAt 109844 /> 603 5 · Insulated cable according to claims 1 to 3 »characterized in that the insulating layer consists of a cross-linked
Polyolefin, which is an ethylene / vinyl acetate copolymer, 6. Insulated cable according to claims 1 to 5, characterized in that an inorganic layer is added to the insulating layer
Filler such as talc, clay, etc. is added. 109844/1603 BATH ORIGINAL