DE1640287A1 - Wire with thin-walled insulation and the process for its manufacture - Google Patents

Description

G. Lofhar Mkhadis

Patent attorney

6 Frankfurf / Main 1

Po.tfad.30t1

Horst student Dr. Hard Patent attorney p "t? Zl ^

ο Frankfurt / Ma InI ₆ F ^. 20 P.O. Box 3011

Frankfu Po H A

8O7-41D-96 / UD-252 General Electric Company, 1 River Road, Schenectady, N.T., USA

Wire with thin-walled insulation and procedure see below its manufacture

The invention relates to a wire with fire-retardant, thin-walled insulation and a method for producing this wire.

The terms "thin wall" or "thin-walled wire" used in the description and the appended claims retired on the insulation of the wire with a dioke

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from about 0.127 to 0.508 now (5 to 20 mile). Farther the terms "wire" and "cable" are used as synonymous terms in the description and the appended claims.

For several years, there has been a need, particularly in the electronics industry, for thin-walled, inexpensive wires or cables with good electrical and physical properties. Because of its versatility in the industry, this wire is sometimes counted among the thin-walled switching wires and is suitable for rated voltages up to 1000 V This wire finds extensive use in many applications such as in data processing systems, Messgeräteauarüstung, navigation devices, Lenksyatemen, nuclear radar _a Electronic assemblies, portable shortwave receivers, electronic devices and devices used in electromedicine, but also in equipment for spacecraft and missiles. Because of the wide range of applications, the wire must have versatile properties and it should continue to be economical to manufacture. These properties include high dielectric strength, low relative dielectric constant, high thermal strength, resistance to damage from soldering,

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good resistance to radiation and corrosive chemicals and solvents »no degassing at extremely low pressures, e.g. at 10 Torr, high adhesive strength compared to conventional wrapping materials and fire retardancy, which according to a horizontal flame test according to United States Federal Specification J-C-98, Method 52-11 is measured. There are currently 2 commercially available thin-walled jumper wires that contain most of these desired ones Have properties; It is the polytetrafluoroethylon (Teflon) wire and the irradiated polyethylene wire. However, both products are expensive and cannot be compared with the wire of this invention encapsulate lightly.

In a broad sense, the thin-walled one according to the invention contains Wire a metallic conductor surrounded by an insulating layer made of chemically linked polyethylene. The insulating layer has a nominal wall thickness of about 0.127 to 0.508 mm (5 to 20 mils), and especially one Thickness from 0.25 * to 0.381 mm (10 to 15 mils). The surface of the insulation layer is etched on its periphery, namely sufficient to improve their adhesive properties, and a fire-retardant coating is made on the insulating layer a thermosetting, halogenated polyolefin if possible

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uniformly applied "The fire-retardant © coating is fully connected with the insulating layer and has © ine thickness of etws O _$ Oia7 to 0.0508 mm (0, S bit 2 mils) and ■ voraufpwGisis v n about 0.025 ¹ I to O ₈ O] IBl ram (1 to 1, the sÄelä GPg © BSO "l © thin walled wire ISIT geringasi G® UKD small Dupchmöseer has alie" desired properties on _s öf.e FÜS ⁵ © lektiORip.che applications and applications lsi äö.i ¹ Ra ^ mfsüirt; arford &i'lich are ^ is also sworn and bc-aifeat a * high degree of clinging resistance to Hü2, ln; öi.ep.i © l; le5i, This means that an oios ^ lner D '^ shfc can be used in wide areas <

To "the invention ßcmauer eu bes <shro £ ben _s is now made to di © attached Seichnungen that © ine preferred 'Ausführungsforra the invention Presenting & tic In the drawings

Figure 1 is a perspective view of a cable of typi shear construction, with certain parts in the drawing are omitted to better illustrate the purpose of construction deliver and show features according to the invention see below, and

Figure 2 shows schematize !? the manufacturing process of the Wire according to this invention.

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FIG. 1 shows a thin-walled wire according to the invention, which is a cable, generally identified by reference numeral 10, for example for radar or airborne body wiring, which is suitable for a nominal voltage of up to approximately 1000 V. The wire contains a metallic conductor 11, which is drawn in the form of a subdivided conductor, although the conductor can veretändlisher be solid. In general, for example, the conductors for thin-walled wires © are cables in a size from number 2k to Numraex ⁵ 3.4 AWO with, a Durehmesssx »from Ο ₉ 35 to 1.7593 mm (0.025 to Ο ₉ Ο 9 inigh) o The conductors look similar stranded wires, consisting of copper, tinned copper, silver-plated copper or aluminum and their alloys. Usually, a peel-off hole 12 is inserted between the metallic conductor 11 and the insulating layer 13, which enables the insulating layer to be easily stripped off the conductor. The release layer 12 can contain paper or plastic that is wrapped around the metallic conductor or it can be an organopolysiloxane, e.g. a dimethyl silicone fluid that has _{been applied to the metallic conductor, for example by spraying. The insulating layer 13 8 expediently has a nominal wall thickness} from 0.254 to 0.381 mm (10 to 15 mils) has “ wivd manufactured to be

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for example via the metallic conductor and the release bar (trap used) is pressed on. Di © Iaoliarsehicht contains chemically crosslinked polyethylene, which is a is known material and in the unhardened state without further notice is available

The surface of the insulating layer 13 is on its periphery etched, for example by flame etching or corona etching, to improve the adhesive properties. With this The surface of the insulating layer becomes fire retardant cover 14 made of a halogenated polyolefin bonded,

'If de? is thin-walled isolated "wire to familiarize cable reel rolled beataht at closely spaced wires di & tendency to stick together on the cable roll or" caking "and thereby damage the casing during the rolling of the wires * In order to avoid this difficulty, on the surface of the insulated Br- ahfcss a sofa layer 15 is applied, which prevents this unwanted sticking. A typical covering, which prevents the aa unwanted sticking together, contains an aqueous solution of a methyl cellulose protein mixture, which can be applied to the insulated wire by running the wire through a bath of the mixture the coating is dried at an elevated temperature of about 107 ° C (225 ° P).

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J-Äi ⁵ ! © Drtht ^ ird dftras "" f? 2 © i ⁵ öb "x"? Ife © fe © g ^ Htsti Before "ugeisc- a fli" iai® ns is made "at a © r Qasflamme hits directly on the S @ t insulated tar * surface. The Xtaung can "was by anean" means, such as

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Koronaätsung example, be carried out, but the invention is besohrieben below with reference to FlammehätEung. In this operation, the insulated wire 23 is passed over a gas burner 25 in order to expose the surface of the insulation of the flame 26, whereby the wire is heated and the surface is applied on its circumference. The duration of the flame treatment required to achieve an improved adhesion characteristic of the surface depends on various factors. This includes, for example, the temperature of the flame, the physical strength of the hardened insulation layer, the speed at which the metallic conductor is guided past, and the diameter of the metallic conductor. Therefore, under certain circumstances it may be desirable to extend the flame treatment EU or to place 2 or more gas burners at a distance around the insulated wire. However, the wire with the conductor and the insulating layer is relatively thin, and therefore the treatment with the flame should be adapted in such a way that the electrical and physical properties of the wire are not all too significantly changed, or that the wire is preformed or otherwise damaged will.

In a device 27 sur application of the upper suction a hitE-curable halogenated polyethylene solution as a fire

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Hensaende mass is given, and the gätste Di * aht 23 is passed through at least one such device to apply the sheathing to the wire. In the next preferred embodiment, the twisted wire is passed through the device 27, while it is no longer exposed to the flames, which means that it is more intimately covered, the thermal radiation from the insulation can facilitate evaporation of the solvent, and so on accelerate curing uMB halogenated «! * Polyäthylen® or © r better. D®r is © li®rt®. Wire? © iE © K TroQkenofsß 28 qualified ₈ a © r

cinsr Tsasperatur swisehsa © tw »'120 unü l§0®6 (250 tnifl 3 bat-2» iabe-ß will, wsl the L8g * a2gsisifcfcel in evaporate, and to continue with the hardening? iend @ K coating ttahullung should be Dick® vep. about 0.9127 part O, O5O8 sas (0 _a 5 to 2 mils) b® ~

and therefore kmm m wHüeohen «wa3? t no, to wrapped v @ n the furnace 28 dtis> @h the Aufbringvorriehtusig 27 suf6hr9n> Ef 1st & ® @ hm ^ glieh _s in €« m ^ / aFfmfei ¹ ® ^ a © de ? mehrer® eueätslieh® tofferißg ¥ © rri © ht “fig @ ii for di® Vsl covering SU imnftm & ifiu Dl © Getr ^ oknete is”, £ hardened feueif- hawmmüm covering is pirnktimti completely connected with the insulating layer. An oversug is then applied through its device 29, the "usaiamenkl" ben of the wires.

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prevents, and the fsrtlggeatellfce wired product with the · fire-retardant Wrapping is sohlieisliafc on a roll 30 wound up.

Föl ^ äthyiaiiisöliarniaterial is usually added a small amount of organic filler in order to increase the coloring ability. Suitable fillers can contain 8.B ₈ Aluminiurasillkat odax ⁵ titanium dioxide, and Morden te of the Gi ¹ Osgenordnung of 2 to 5 Gawichteprosenten & er «ar Löola & lonaaiasae sugesatzt. ,, Die Polyäth ^ l

can Weltsrfsin tirni gsringa crowd sina »anti onthaltoüi, as beiapielswuiss

Dihydrtrimethylehiiiolln (disclosed and in UdF üS-Pafeentsohrift Ka. T> 396 189) to i! I® A eig @ a38haft © ji dsr 2iiöEssnenBefc3ur ₅ 3 eu "/ erbessärn. In general, the anti-aging agent can be at about 0.25 to 2 Qewichtsprosente der Polyäthyleiiisulationeia & sad fcsiir-a ^ ri ,, .... If desired ;, k & r & si üi
dull «? a 'pigment © ijtiii

Parb® od®r begfciimS® Manufacturers' aids βϋ announce _β Di® »© expressions e <tr & and can be determined by Faohleut®.

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During the production of the insulation compound, the polymer and other fillers, such as an antioxidant, are mixed or intimately mixed in a Banburyra mixer. Then a suitable hardening agent, expediently a tertiary peroxide, is added to the mass in order to achieve crosslinking of the polymer during hardening to keep a processing sufficiently plastic, but which is below the reaction temperature or decomposition temperature of the hardening agent, so that practically little or no decomposition of the hardening agent occurs during a normal operation. The resulting mixture is then processed, for example by spraying it onto the conductor, which may include a release layer, in a continuous process. The product produced is then cured, such as by conventional steam vulcanization at about 16.5 atm (250 psig) and 205 to 210 ° C (400-110 ⁰ F).

Desirably is that used in the method Hardening agent a ferric oxide, preferably a tertiary one Peroxide, and by at least one structural unit

' t

C-C-O-O-C-C t! C C

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ORIGINAL

marked ₉ replaces the cioh at a temperature above 130 ° C «;. The use of these peroxide curing agents, which bring about crosslinking in the polymeric compound, is adequately described in US Patents 3,079,370 and 2,888,424. Another useful curing agent contains the tertiary diperoxides, such as, for example, the aaetylenic diperoxide compounds disclosed in US Pat. No. 3,214,442g. The disclosures contained in these patents are incorporated into this application by reference.

The quantity ratio of the peroxide curing agent used depends largely on the mechanical properties sought in the cured product, for example on the Varmeer tear resistance. A range of about 0 _t 5 to 10 parts by weight of β parts peroxide per 100 parts of the total polyaer content meets most requirements. üb Liehe J * weiee about 3 contains the mass to H Oewichtstell "peroxide" Xn of a typical manufacturing process, in which a tertiary Peroxydi is used as Härtungscittel, the mixture is at a temperature between about 100 and IJSO ⁰ C and preferably "wipe 100 and 120 ⁰ G carried out. If the mixture is carried out at a temperature well above the specified maximum, the peroxide decomposes and thereby becomes a

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causes premature curing of at least part of the polymeric compound. As a result, the mass will be difficult to process and the end product will be inconsistent and have a rough surface.

The fire retardant compounds useful in this invention include thermosetting halogenated polyolefins, for example chlorinated polyethylene, chlorosulfonated Polyethylene and fluorinated propylene copolymers. Ale especially Heat-curable chlorosulfonated polyethylene became useful which is commercially available and sold by a manufacturer under the trade name "Hypalon". In this Hypalon series, chlorine is in the range of about 29 to Ίο weight percent and sulfur is in the range of about 1 to 1.5 percent by weight present. The halogenated polyolefin contains a small amount of a suitable one Hardening agent, such as a metal oxide (e.g. magnesium oxide), such that at the temperature and time used in the process of making the wire, the halogenated polyolefin is cured or crosslinked in place will. If desired, the fire retardant topcoat may contain a coloring pigment or dye for color identification. A suitable pigment may include titanium dioxide, and may be in an amount of about 30 to 45 percent by weight, based on total pigment and solids

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Binder, be present. Furthermore, the coating mass A small amount of a non-flammable additive can be added in order to increase the fire-nosing effect. this can for example duroh antimony oxide in the amount of about 5 to 10 percent by weight of the total fixed portion «can be achieved.

The fire retardant coating is generally applied in a solution or in a suspension. Therefore becomes a suitable solvent used »that essentially consists of the coating mass evaporates, naohdea the coating is applied has been. Suitable solvents as they are soluble in Ohloreulfonated polyethylene can contain benzene, toluene, xylene, and similar aromatic hydrocarbons. Suitable solvents can also be used just as well Chlorinated aliphatic hydrocarbons such as tetrachlorethylene, methylene chloride, Xthylidenohlorid and the like contain and just as well combinations thereof. The amount of solvent used can vary within a wide range and depends on factors such as the thickness of the coating desired, the particular fire retardant compound used, and the type of solvent. In general, the But amount to about 10 to 50 percent weight of the total pesticide. The fire retardant coating can be single or

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should be applied several times, and in general, after evaporation of the solvent, it should have a thief of about 0.012? to 0 * 0508 mm (0.5 to 2 mils) and preferably 0.025 ¹ J to 0.0381 mm (1 to 1.5 mils). If the coating is below thick, occur for this adverse effect hlnniehtlich the Alfceruag, which © in-Zerbrse-hen the Isolationsseiiiehten is effected in esrtr-ess low pressures eina degassing can warden causes _s or the solvent can not · evaporate completely "which © occurs in sticking or "caking". In general it is desirable to use “Sne minimal © fJbePc
ua -iar exam ? ilr- the FaysrhesiSHmg: £ t

ta

The invention is explained in "eiterfeiE nnkmä ^ r ^ f LSSO (the Γ 2 <o sent information li ^ üie-feee they-fe emsff prosente):

It was polymerized a loolationsmisehung from about 95 _a O9% polyethylene, 1.785%, i ₀ 2 »Dl! Iy (aro-2 _e 2 _B 4-trimeth3fl" shinolin (an antioxidant) and 3.125% Si ^ fc-öurnyl-papoxyd (Hardening agent). The compound is pressed onto a divided conductor made of insulated copper 'lsi? Htamaer 20 AWQ (American Wire Gauge) to a wall thickness of ^ eR Q ₀ Z5 ^ mm (10 »ils!) And placed in a steam chamber a Dr «®k of about

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Hardened 16.5 atmospheres (250 psig). The isolated one. Wire was then flame etched »using a natural gas flame from a burner acted directly on the surface of the insulation layer » The etched wire was then passed through an applicator containing 25 percent by weight of the blended thermosetting, chlorosulfonated polyethylene contained in a Mixture of toluene and methylene chloride was dissolved to form a final coating on the insulating layer with a nominal wall thickness of about 0.025 ^ to 0.038 l mm (1 to 1.5 mils) form. The coated wire was then passed through a drying oven heated to a temperature of about 120 ° C (250 ° P) was held.

The cured insulation mass of this wire has a specific weight of 0.93 g / onr, a tensile strength of 158 kg / cm ² (2200 psi) and an elongation of 300 %. The finished wire had a relative dielectric constant of 2.7 at one megahertz and an insulation resistance greater than 98.7 * ¹⁰ M & x 1 km (30,000 megohms χ 1000 feet).

Numerous tests that are common for evaluating a wire of this type have been made, and the wire was compared with common, known, thin-walled wires.

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The wire, according to the description above of the invention is hereinafter referred to as sample 1 and it has been commercially available with 2 known available, thin-walled jumper wires, which are referred to in the following as samples 2 and 3. Sample 2 contained a copper conductor number 20 AWQ with an irradiated polyethylene insulation with a thickness of about 0.254 mm (10 mils). Sample 3 contained a copper conductor the number 20 AWQ with a polytetrafluoroethylene (Teflon) insulation with one? Thickness of about Ο.2§4 nira (10 mils).

The wire samples were tested with regard to the bond strength against conventional sheath connections or potting compounds. These compounds are known in the art and include, for example, epoxy compounds, polyurethane compounds, and silicone compounds. In general, however, the waxes and Aufschraelgverbindungsarten are not ₀ because the Tesnperafeurgranz® is for thin wire © brau9fobar rolativ low. The mixtures are poured or pressed and should show minimal shrinkage after hardening. Furthermore, the casing materials should be suitable for filtering out sudden fluctuations in temperature and protection against other ambient conditions in addition to temperature »wl © for example against moisture,

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Development of sponge or fungus, chemical contamination and irradiation, and they should also face mechani It must be resistant to shock loads * Dia tests were carried out by placing the wire samples 2.5 * 1 cm (1 inch) deep into casing fittings or potting compounds were, ufid afterwards the cover exercises could be canceled with an Instrom testing machine was the necessary force in Kilopond measured to the connection «wipe the ur & ht and of the hardened potting compound * The results are shown in Table 1 below.

Table 1
Verbundfeatigkeit the Hfl1! Connections

Shell connection Epoxy connection No. 26S1 Styeast with No. 9 CatalyaB »rfherge» telit by Emerson & Cumings)

Sample 1 sample 3

12.4

5.80S 2.3133

Polyurethane compound 8.43 5.4431 Ο _β 68θίί

No. CPC-Ιβ Styeast (manufactured

by Emerson 4 Cumings) (1β, 3 p) (12, O5 p) (1.5 p)

RW 616 silicone with QE

SSÜ12G Primer (manufactured by Qensral Electric)

2.903 2.5 * 01 1.0433 Cö , * l p>Ci>, ö p) C2.3 P)

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The results shown in Table ί make it clear that a thin-walled teshfc siaoh of this invention over powderers commercially available thin-walled wires are very superior in terms of adhesive strength »

The invented wire was subjected to a test under the so-called "oriEonfcalen flaramon test" of the United Sfcatee Federal Specification YC-98 _S method 25. After this test, paper test sheets were placed 8.5 cm (3.5 inches) on each side of each side of the plane attack puncture

Wire ηε ^ -ι lifsftp invention «i'wios eich ala a €? Ib st erasing and üörvÄ ",! £ no fire on the fruit leaves and that was enough the test. An absolutely essential oil-like draiit, however without any excess from the hit-hardenable ehlopsulionate Polyethylene, did not meet the test requirements «On it? see the superiority of the coated wire.

The shrinkage of the insulation was measured after 6 hours in an air circulation oven at 225 ° C _ 3 ° C according to MIL-W-810 44, Paragraph 4.7.5.7. measured, sample 1 showed none at all Shrinkage, whereas Sample 2 shrank 0.397 ram (1 / β'4 inch) ,

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It was performed Lötprüfung, the insulating property hull was gomessen uss, after the wire in a molten solder 60 ¹ IO was eigetaucht 5 seconds daa gemäsß MIL-W-16878 D Paragraph 4.4.2.6. was maintained at a temperature of about 32O ⁰ C. For Sample 1, the results showed a shrinkage of zero percent and for Sample 2 a shrinkage of 0.397 mm (1/64 inohm).

* The resistance at a solder was tested daduroh that a soldering iron with a 80 watt element at 35O ° C (650 ⁰ F) with a pressure of 160 g pressed onto the wires of the sample. 1 The measurement of the resistance to solder damage related to the time during which the soldering iron acted on the metallic conductor. For sample 1, the time was greater than 10 minutes. In comparison, this time comes very close to the wires of samples 2 and 3, which are proven to be extremely good wires

Consistency to be considered.

A smoke test was carried out in still air. An electric current was sent through the wire, and the temperature at the time the smoke became visible was calculated according to that in MIL-W-81044, paragraph 4.7.5. 10. Established procedures.

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The results of this test are given in the following table contain:

Rau chtemperatur

Sample 1 290 ° C

Sample 2 26O ⁰ C

Furthermore, a refrigeration fluid inspection was carried out. At a temperature »of - 65 ⁰ C £ 2 ° C miräa a sample a 19 mn RM (3M inch) thick mandrel wound, at one end of the sample a weight of Ο ί, 53β kg (pound ί) attached? was. After ί hours Prob® gsssäss £ ®n \ ^r © rsehrift @ n was ₆ Paragraph MT ₀ 5.10c electrically tested in accordance with MIL-W-SIO ^ optically uad to tears. Sample i showed no surface cracks uno beoeas a resistance of 13 * 8 kV, nsehd @ ia they »I found in W & ssey for 5 hours. Prob® 2 also shows "no ob@rflächenri.S£e" beeaee but © ine permanent break voltage from T ₉ ^ kV "after being in water for 5 hours.

Mife eteer Prtlfß'a?: F?, Hia © © iitepreshend MIL-W-5 ¹ · 33 ^ aI ⁹ Oe an abrasion resistance test was carried out. Eb was in 400 sanding tape with a weight of 0.22 68 kg (1/2 Ib) with a tension of ₉ 453 kg C 1 pound) ("A" bracket). Destruction was determined in accordance with MIL-W-SLO ^ Ii, Paragraph 4,, ·, 7.5 «9Ί». Egg oils were average

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Tape lengths measured in centimeters until destruction occurred. Diö Ergübnissa resulted in sample i 13 ^ »ö2 cm (53 inehec) and for sample 2 76.20 cm (30 inches).

A cufc through test was carried out by applying a "/ -like blook with a radius of 2.5 * 5 x 10""'mm (0.0001 inch) at. ™ at a constant speed of -5 * 08 mm / minute (0.2 inch / min) is lowered onto the sample _s and it was the force in kiloponds determined bowirkts the sine destruction. the results were gamessan at a temperature of 23 ° C. sample 1 was at 2.903 kp (5, k pounds) and sample 2 destroyed at 3.0391 kp (6.7 pounds).

For a winding test, samples that were all 3Q, HB cm (12 inches) long "around a vain" mandrel h _t 35 ^ i (ά / η inah) were wrapped, and with regard to their?! ^, "Isruiig gssiiäB MIL" W -810 l \ k, Paragraph 4.7 · 5 · 11 »checked» Di · Results sy = · entered for Pi'öbe 1 a DarohbrushsapatiniÄng of Π * $ kV and for Prob® 2 a throughbruehsapanming of 11.3 k7 _e

The samples of the wire tea according to dissar invention were then an irradiation in the form of hosh-energetic flowers from an 800 kV electron source with a radiation dose

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exposed at 10 to 12 megarads per minute. After this irradiation the samples were once by a 12.7 nm (1/32 inch) The mandrel was wound and a tension of 2.2 kV logged on. Then the voltage bi3 became the breakdown voltage increased. As described above, samples 1 and d 2 gave good results in this test during sample 3 turned out to be very bad »

The wire of the invention is also resistant to many solvents and reactive chemicals. Vegetables of the liquid immersion test, MIL-W-810M, Paragraph k. 7.5 · 15 * »the sample: i of the wire was immersed in appropriate organic liquids for 20 hours. After they were taken out again, they were tested for a decrease in dielectric strength and abrasion resistance. Pzobe 1 showed no significant change in dielectric properties or abrasion resistance after the sample was dipped in isopropyl alcohol (MIL-F-55 66), hydraulic fluid (MIL-H-56 06), JP-4 aviation fuel ('4IL -J-5t 21), ethyl alcohol (MIL-A-60 91), lubricating oil (MIL-L-7i3 08) and Skydrol 500 A.

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It's special he \ applications in space and missiles v / ünaehettBvcrrt, the wire daoo at extremely low pressures shows no degassing. The degassing test was carried out in a vacuum system which was evacuated to a pressure of about JO mm Hg. The evacuation rate of the empty chamber is shown in Table 2. If no degassing occurs, the pressure decrease during any temporal evacuation period should be equal to the corresponding values for the empty chamber and be of about the same magnitude "" order. Thus degassing is characterized by a slower pressure decrease. Ee can be seen from the table below that sample 1 showed a pressure decrease which was essentially the same as the values shown for empty bodies, so the sample can be considered non-gassing.

Table 2

Time (minutes)

2 3

15 25 60

Entgaeungsprüfung chamber 10-5 Chamber with sample 1 6th Hg) ίο "' empty Hp) 10-5 (mn ι Η X ίο "* (mm χ 10-5 2 X 10-5 9 χ ΙΟ "« 3. ,1 X ίο- « 6th X ΙΟ "« ,1 X ΙΟ "« 3.2 X ΙΟ "« 7th .5 X ίο- « 8.2 X 5 « X 4.5 X 2, 2.2

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Furthermore, a Sr / nnallfclfce-rangsprtlfuna; at a temperature of 225 ° f! "Purely this test was carried out on each end of a 50.8 cm (20 inches) long sample of the finished wire 2.5 ¹ cm (one inch) of insulation removed." a 38.1 mm (1.5 inch) diameter knife. The ends of the sample were tied together and loaded with a 0.536 kg (1 pound) weight. The sample was then placed in an air circulation oven at a temperature of 225 ° C + 4 ° C for 4 hours. The flow rate of the air sliding along the sample was between 50 and 150 cm per second (100 and 300 feet per minute). The sample was then cooled to room temperature, unwound from the mandrel, and elongated by attaching one end of the sample to the mandrel and a 0.1 pound weight on the other end. Then the mandrel was rotated slowly had been wound up to the entire length of the sample around the mandrel and was under the particular train, the turns themselves aneinander-

■ touched lying down. The mandrel was then rotated in the opposite direction until the entire length of the wire, which was in an external position during the first winding, now came to rest near the mandrel. The sample was then unwound and immersed in a 5% solution of sodium chloride in water at a temperature of 23 ° C to 3 ° C with the ends protruding 38.1 mm (1.5 inches) above the surface of the liquid. After immersing the sample for 5 hours

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BATH

was, it was then tested for its breakdown voltage and should have a voltage with an effective value of Withstand 25OO V. When carrying out the experiment, the The initial voltage should be greater than 500 V, and should be 500 V can be increased per second. The wire of sample 1 produced according to the invention had a breakdown voltage of 12.3 kV. This can withstand a temperature load of 125 ° C are equated »

009834/1508

Claims (1)

Claims 1. Ieoliertcr Brtshi ,, characterized by a) a metallic conductor b) a den set & llisehep head uisg6toc * nde Isel & fcion chemically combined polyethylene, where the insulation is ine Wall thickness in front of * 0 * 127 rock 0.508 ram (5 to 20 mils) and one to the extent that it has shapes, and o) a hardenable, suspended polyolefin cover that surrounds the insulation and has a thickness of 0.0127 to 0.0508 mm (0.5 to 2 »ils). 2. Insulated wire according to Anapitsoh 1, d & duroh g «- kennreiöhnet, <3 & i «dl« valid surface & oh « flame etched let. 3. Isolated Eroht n «oh Mspruoh 1 oä% r 2 _t ά & ά η τ α h labeled, the *" Sa "hiteehA ^ tbar" halogenated polyolefin a chlorosulfonated polyethylene l / t. Insulated wire according to one or more of the angles 1 to 3, characterized · that the wall thickness of the insulation 0.254 to 0.381 nm (10 to 15 alls). 009834/1508 BATH 5. The insulated wire of claim 1, characterized in that the thickness of the polyolefin ^{coating is 0.025 1} J to 0.0381 mm (1 to 1.5 mils). 6. A method for producing an insulated wire according to claim 1, characterized in that " that a) via a metallic conductor a polyethylene and a hardening agent containing thin-walled insulation layer with a nominal wall thickness of 0.127 to 0.508 (5 to 20 mils) is sprayed on, b) the insulation layer is hardened, c) the surface of the hardened insulation layer on the perimeter is etched, and d) the surface of the hardened insulation layer is coated with a thermosetting halogenated polyolefin, the coating having a thickness of about 0.0127 to 0.0508 mm (0.5 to 2 mile). 009834/1508