DE2623325A1 - METHOD OF CONTINUOUS MANUFACTURING OF A COAXIAL HIGH FREQUENCY CABLE - Google Patents

Description

Cable and metal works Gutehoffnungshütte Aktiengesellschaft

llwerlce 2 Q- * 0 4 ft Q

1 1469

May 21, 1976

Process for the continuous production of a coaxial high-frequency cable

The invention relates to a method for the continuous production of a coaxial high-frequency cable, with an inner conductor and an outer conductor surrounding this at least partially concentrically, between which one from foamed plastic existing insulation is attached.

Such coaxial high-frequency cables are used with a closed outer conductor for low-loss transmission of high-frequency energy, for example in community antenna systems or in television reception and distribution systems or they are with perforated outer conductor as a radiating high-frequency cable used. In the following, these lines are referred to as HF cables for short. There are all sorts of things on the market Coaxial RF cables available, which are characterized in particular by the shape of the insulation between the two conductors, also called Spacer is called, differentiate. Such spacer For example, disks or coils made of plastic are placed on the inner conductor at intervals, which surround the inner conductor.

There are also spacers known that the Completely fill the space between the two conductors, solid or as foam. The respective shape of the spacer is dictated by the requirements in electrical and mechanical terms. It would be electrical on

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best if there is only air between the two conductors would be, which / is not possible for mechanical reasons. To achieve the best possible damping values Therefore, when the space between the two conductors is completely covered, a foamed plastic is used for this insulation which, however, has the disadvantage that it can only be used in is watertight to certain limits. Compared to the massive Such foamed insulation is also insulation lighter, but compared to insulation made of panes or from a helix, in turn, heavier. Besides, there is such a thing Foamed insulation then mostly not usable if the cables are exposed to high temperatures for a long time.

The invention is based on the object of a method for Manufacture of a high frequency cable i-ii t foamed insulation indicate that this is easier with improved electrical and mechanical properties and for high temperature loads suitable is.

This task is carried out with one of the following methods: Kind according to the invention solved in that the propellant and crosslinking agent containing plastic by means of a Extruder is applied to the heated inner conductor, and that the plastic in the extruder between the inlet and the outlet opening is heated so that the temperature immediately in front of the outlet opening above the Realctionsteinperaturen of blowing and crosslinking agents.

The use of this process results in an HF cable with foamed insulation that is unlike comparable cables is reduced in weight and has a high temperature resistance having. With the method according to the invention, an insulation can be produced whose density is in the Order of magnitude of 200 ^ g / m and the one floorboard

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'' ons tan te / wi ropes 1 »3 and 1, ~ - a; i ίΐίί: i st. L »rrcii the networking of the cffschäii.'iten. ! .sol i ovu ng we improve the same so that it guarantees the concentration between the inner and outer conductors of the IiF label even at high temperatures. Yes the; ea ' ^r tions te.nperar.ureii de? IVei b: ii ttels and des V e.'Yi ct / .ungs .ii t; .els are already exceeded ir.i extruder, exits de ι ιϊΐ. I extrude an expanding sleeve for the insulation, which is cross-linked and further cross-linked when expanding outside the extruder. It is essential for the method according to the invention that the Hea''ti.oastfocketatiii-eii for the Venietztni ttel and the propellant iniierhal'o Viitv.Hster / 'eic are submitted and exceeded. I "ii -.!) It '-» ibar after ne-n Ulierschreiteii der itea ¹ · -1 i onste: .iperntu.r des i / efji ^ t / utiiisiiiti els nut υ ι e i'on'igebun.a ; Tür fiie LsoliBtuisg er ioi; pii, d. Ii. (lie öch-nelr.e leave the Ext. »- udericop Γ. Uie Erwä füiuii.'x des Kunststoffe '' anii to 'nirz below the HeaVtionsteü-if'i 'atui dop Vpriierung: ii11els iii .extruders must be.

ij.s has turned out to be particularly twofold, this Erxvärrain ;; by ache run * ξ to generate. This Varm, for example, dnd'it'c; · is achieved that in the extruderV o] jf a rotating doi si is adjusted, the speed of which is adjustable. The speed influences the shear rate and thus the heating of the plastic. to be set ^ ami. The heating dei ^- plastic mixture innerlialb Wirzester time, however, can also be made by a known Höchstdruclqilastif i zi enlargement.

Lia's ancestors according to the invention will be described below with reference to the Drawings explained for example.

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i'ig. 1 shows a section .luic.i eic Mi cable as it; ^r > ii: de: 'i procedure nnch der ErI in dun ti! iprse.stel.lt who -:.! en ^ ai: ^, and in 1' i & -. 2 is a sch-üati.scli a .'iirs i ent mg /.ur guiding this procedure.

The Hi "-Ka at, kpJ dies ni I. de .: ν er 'nli'.» In naci · .Ter , Lt i ": i.iJ-n: ^ iier ^ nst '!'] '; x.ird, consists of «a ;! ir.iieul e ί t.ei 1, uer beis [ii. instructions a 1 -s kiii ;! eidrali! fm. « μ r .nh ft is, one iü.-er Ae '·. innp.ttlci ter I i pcetiden reschiit: -tr-n ί. ί - ο 1:. e ι <.; - .. ι: 5? , egg. m: - ¹ OIIZPu ti ·> SC h /,;.·.! lim Pille it Pf Ρ.Ιί BOO Ι'ΠΤΙ f · t θ! Ί AllßnU Piter T ui ": fi ei ne-Ί iibei dem Außenlei, t.et ·! i ei · enden Schu t"'nantel' s nus Kiirisi st.o; f. ijer exterior I ei ter 3 '-FIN · eiicnfails a-is copper "; estelieii hr; as if schiüssenes üoSir from _f be iet Iebi 1 <pi!.' -anri Jedocri also: it DurchbT'echiutrrei.! provided "pt ti, di r · .. VP ^ public in the axial i'iclitung verlan'pii μχ · '\ t vx.t AIIS i'ahliiTi;.'.?. · rlieuen of floclif" i "s equenzenergi to. bessf-rpu 'Ai eu har ¹ -e?. ti ^; es ilF-Kabel it is still possible to use the ArRenlei te: * °,; -i; vrelier ·.

When making the Ji; -Cable ce: .iäß i ii- ^r . 1 the procedure is such that the inner conductor 1 v of a Tro> withdrawn .e1 ~ and seinrichtung initially in a heating is heated to a temperature of about 13 (5 C. 6 This erwär '.re J in onleiter then passes into a Lxtrudpr ", into which is introduced through the opening 8 a pla f ^r fvi.sctmng that already contains a blowing agent and a crosslinking agent in which it furrlerl i rhen Zusanmensetzung. in this"'. extruder the Kmiststo r Γ-inischung from. Ziirn inlet to outlet temperature NIIT zunehaender heated and ^v urz- as much heated that the Rea ^ -ti on Steinn era doors of Treibisuttel s Venietzungsi and before its exit from the extruder de'n. ttels be ii exceeded, so that the Extruder leaves an expanding, partially cross-linked Schnelzo. In this way, the inner conductor 1 receives the desired insulation 2, which can then be cooled in a cooling section 9 to such an extent that it achieves the required stability.

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skin, lüiiτ.or rler cooling section is the outer conductor 3, animal as a band running from a reel 10, un the insulation 2 heru-length ^r or: nt and the finished RF cable may optionally after application of the outer:; iau t el s k are wound onto a Trormnel 11.

Essential for carrying out the method according to the invention, therefore, is the right processing and temperature treatment of the plastic mixture! For the isolation 2. The crosslinking agent should be added in such a jienge that is reached at the exit from the extruder, a cross-linking degree of at least 10%, of the iin the foamed state of the finished insulation reads at at least 35 % . The blowing agent used should be added in such an amount that the foam produced has a density between 50 and 300 l-g / mn. The reaction temperature of the crosslinking agent is to be chosen so that it is below the reaction control temperature of the blowing agent. As a result, the crosslinking of the plastic begins earlier than its foaming.

Furthermore, it is advantageous to smooth the outer surface of the final isolation and to condense, which is particularly desirable when the finished door cable will have a greater water-tightness required. This process can be accomplished, for example, by sending the expanding insulation through a heated Ilatrize or by designing and tempering the dog piece of the extruder in such a way that the insulation is foamed smooth and less strongly. Furthermore, it is possible to design the cooling device 9 in such a way that this smooth outer skin of the insulation is achieved by a certain cooling.

The plastic mixture, which in a special mixing device sufficient before introduction into the extruder

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is homogenized, it is first heated to a temperature of about 130 ° C. in the extruder. The screw of the extruder 7 then transports the plastic mixture in the direction of the mouthpiece of the extruder, in which a mandrel is rotatably mounted is. As this mandrel rotates, the plastic mixture is continuously heated, which then directly affects the reaction temperatures of the blowing and crosslinking agents used must be exceeded before exiting the extruder. The reaction temperature of the crosslinking agent is here around 150 ° C, while the reaction temperature of the blowing agent can be 180 ° C. The outlet temperature of the Plastic mixture should be in the area of the mouthpiece of the Extruder 7 at about 190 ° C.

Two examples of the composition of the plastic mixture are given below, as used for insulation 2 of coaxial cables can be used in the method according to the invention:

1. A plastic mixture of the following composition is used:

100 parts soft PE

0.8 parts peroxide

2.0 parts propellant.

For example, a material known under the trade name "Lupolen 18IO H" is used as soft PE, as peroxide A dicumyl peroxide can be used and as a propellant a material that has become known as ADCF is suitable. This mixture is in the extruder 7 on applied to the inner conductor 1, which was previously heated to a temperature of about 130 C.

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2. If harder insulation is required, then this is suitable also the following limaterial:

50 parts of Xieich-PE
50 parts Ilart-PE
0.3 parts peroxide
2.0 parts propellant.

Here, too, the inner conductor 1 is heated again to a temperature of about 130 ° C. before being introduced into the extruder 7.

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Claims (1)

Gutehoffnungshütte Aktiengesellschaft 1 1469 May 21, 1976 Patent claims lj Process for the continuous production of a coaxial high-frequency cable, with an inner conductor and an outer conductor which surrounds it at least partially concentrically, between which an insulation made of foamed plastic is attached, characterized in that the plastic containing propellant and crosslinking agent is made by means of an extruder (7 ) is applied to the heated inner conductor (1), and that the plastic in the extruder (7) between the inlet and outlet opening is heated so that the temperature immediately in front of the outlet opening is above the reaction temperatures of the blowing and crosslinking agent. 2. The method according to claim 1, characterized in that blowing and crosslinking agents are coordinated so that the reaction temperature of the blowing agent is higher than the reaction temperature of the crosslinking agent. 3. The method according to claim 1 or 2, characterized in that the plastic is cooled from the outside after exiting the extruder (7) and before the application of the outer conductor (3). k. Method according to one of claims 1 to 3 » characterized in that a plastic based on poly- 709850/0021 " ² " ethylene with the following composition is used: 100 parts soft PE 0.8 parts peroxide 2.0 parts propellant. 5. The method according to any one of claims 1 to 3> characterized in that a plastic based on polyethylene is used with the following composition: 50 parts soft PE 50 parts hard PE 0.8 parts peroxide 2.0 parts propellant. 709850/0021