CH638923A5 - Cable screening strip which is capable of resisting corrosion, and use of the same for insulation of an electrical cable - Google Patents

Description

The invention relates to a corrosion-resistant shielding tape for cables and the use of the shielding tape according to claim 1 for the insulation of an electrical cable, which has at least one insulated conductor as a cable core, for protection against corrosion.

In the construction and design of electrical cables, in particular telephone cables, it was previously known to combine insulated conductors into a core and to encase them using various components. A telephone cable of this type is referred to as an “Alpeth” cable, which is used, for example, in the publication by F.W.

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Horn et al. paper "Bell System Cable Sheaths Problems and Designs" in A.I.E.E. publications 1951, volume 70. The shielding tape of the "Alpeth" cable consists of a layer of pure aluminum with a density of approximately 0.2 mm, which is normally corrugated in the transverse direction before being placed around the cable core. This corrugation gives the cable greater elasticity and better bending properties without the shielding tape folding or breaking.

The shield described in this specification is a thin layer of any metal, which can be bare or coated and is used for mechanical protection and for electrostatic and electromagnetic shielding of the conductors in the core of a power or telephone cable.

Telephone cables are often laid directly in the ground, whereby the outer sheath of such cables, which consists of a polymer resin, for example polyethylene, can be damaged during laying and by stones, rodents, lightning, cold and burial. As a result, the underlying shield can be exposed to water or saline solutions, which create a potential for corrosion.

If the outer sheath of such cables consists of a polymer resin, the sleeve does not stick well to the shield made of bare metal. The outer plastic sleeve tends to slide over the shield and form folds when the cables are pulled through channels. The shield also tends to buckle, ripple or twist during installation, so that fatigue breaks in the belt and, in exceptional cases, breaks in the belt can occur as a result of the mechanical bending processes.

To improve the corrosion resistance of a bare metal shield, a certain polyethylene adhesive can be used to cover one or both sides of a metal strip, as described in U.S. Patent Nos. 3,233,036 and 3,795,540 . Such shielding tapes are widely used in the manufacture of electrical power and telephone cables. The polyethylene adhesive for this layer contains reactive carboxyl groups which have an ability to develop a strong adhesive effect against metal strips, and these adhesives can also be arranged over polyethylene sleeves. The metal strip of such shielding tapes gives the cable electrostatic shielding and mechanical strength, and the coating with polymer resin, e.g. Ethylene acrylic acid (EAA), copolymer coating, bindability, sealability and corrosion protection for the metal components. A metal strip, for example made of aluminum, which is protected by a layer of sticky polyethylene, normally has a higher corrosion resistance.

If a polyethylene sheath is extruded onto the metal strip covered with a sticky layer of polyethylene, the heat from the semi-melted polyethylene sheath connects the coated metal strip to the sheath, so that a unit is formed which combines the strength of the metal strip with the ductility and fatigue strength of the polyethylene sheath . Such a cable is called a composite cable. If the heat supplied to form the polyethylene sheath is sufficiently large, the shielding tape becomes sufficiently hot to connect the overlapping parts of the shielding tape to one another at the seam and to form a thermally sealed shield around the core of the cable. The composite cable with a sealed seam or layer is better against the penetration of moisture into the

Cable core protected and has a higher mechanical strength. This is necessary to avoid repeated bending of the cable, i.e. Avoid fatigue breaks in the cable shield. Furthermore, the loads caused by the temperature changes during operation are reduced.

The plastic jacket protects the metal from corrosion to a certain extent by limiting the area over which corrosion can occur and preventing the metal from coming into contact with water and acid. The sheath should be firmly glued to the metal in order to resist any notable separation of the layers by the action of corrosive water and mechanical forces and to limit the corrosion to the exposed metal edges of the shielding tape.

A test of several commercially available cables with a shielding tape coated with polymer resin has shown that the coatings on such shielding tapes are damaged during cable production and that a large number of corrodible, bare spots occur on the surface of the metal strip, especially if a polyethylene jacket is used during is extruded over a plastic-coated shielding tape so that the heat from the molten polyethylene sleeve softens or melts the polymeric resin material coating to create a bond to the jacket and a sealed seam. While the coating softens or melts during this process, it is rubbed off by the soft, corrugated or indented core wrap through the seams of the tape or through the binding tape and / or by the weight of the core, so that a large number of corrodible, bare spots on the Surface of the metal strip is created. As a result, the corrosion ability of the damaged areas is accelerated due to an unfavorable ratio of the anodic and cathodic surfaces of the bare and coated metal. Corrosion also attacks between damaged areas and prematurely destroys the shielding tape, which can lead to the cable being switched off. Because telephone cables are generally designed to last for a long time, corrosion on the shielding tapes leads to premature cable breakdowns and, consequently, is a serious, technical and financial problem. The problem with coating damage has only recently been recognized because of the industry mainly dealing with other main problems. One of these problems was thermal insulation to protect the cable core from damage from heat. Another problem was associated with the introduction of filled telephone cables, in which the cable core is filled with a fat-like mixture to prevent water from entering.

The corrodible, bare spots can appear on both sides of the shielding tape, but the problem is particularly with the use of corrugated metal strips, and it has been found that the damage due to penetration and / or abrasion on the bare spots on the upper locations of the undulating surface of the shielding tape arranged against the core is concentrated. Corrosion of this type on the circumference of the corrugated metal strip quickly leads to the destruction of the effect of the shielding tape. In order to maintain the property of the known designs in which the corrosion attacks the edge of the shielding tape, it is now found that in addition to the resistance to the separation of the layers, the plastic coating must be resistant to abrasion and softening, so that corrosion on the edges s

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of the shielding band is limited, instead of the corrosion extending over the entire surface.

Although none of the existing designs deal directly with the elimination of such problems, the following patents, which are also listed in Table II, come closest to the problem with the technology of the plastic-coated shielding tapes.

U.S. Patent Nos. 3,586,756 and 3,950,605 (Examples 3 and 6 in Table II) describe shielding tapes made from a metal strip with an adhesive polymer layer disposed on at least one side of the metal strip. However, these known patents do not provide a deformation-resistant layer made of a polymer resin mixture which has a deformation temperature of at least 130 ° C. and is explained below in this description. The coating of the strips is deformed during the manufacture of the cable, so that various corrodible, bare spots are created on the surface of the metal strip.

In US Pat. No. 3,507,978 (Example 4 in Table II), a shielding tape with a metal foil is used, which layers of a copolymer, for example ethylene / acrylic acid, which are glued to the two sides of the metal foil, and an additional layer made of high density polyethylene, which is connected to one of the copolymer layers. However, US Pat. No. 3,507,978 does not contain any instructions as to how the damage can be remedied, and an examination of the commercially available cables which have such a shield furthermore shows that there is abrasion in the cable production and service work High density polyethylene layer occurs.

U.S. Patent No. 3,379,824 (Example 8 in Table II) describes a three layer shielding tape which has an aluminum foil connected between two layers of polypropylene or a layer of polypropylene and a layer of polyethylene telephthalate. Furthermore, although these plastic layers resist the penetration of corrosion agents and the abrasion, no corrosion protection is provided because both polypropylene and polyethylene terephthalate are extremely inert and only result in a poor mechanical connection with the metal strip. As a result, both polypropylene and polyethylene terephthalate layers dissolve under corrosive conditions and the mechanical forces that are directly applied to the corrosive metal products.

In U.S. Patent No. 3,325,589 (Example 9-1 in Table II) is a plastic-coated shielding tape with a metal strip and an adhesive that adheres directly to the metal strip and an additional layer of Mylar or polypropylene on one side of the metal strip. Such a shielding tape was subjected to simulated conditions during cable production and a laboratory corrosion test. The tape was found not to have sufficient corrosion protection against metal, i.e. that the rust attack was not limited to the free metal edges. The adhesive layer was deformed by the pressure exerted by the polypropylene or Mylar layer, so that bare aluminum spots appeared. Corrosion was observed in these bare spots after the cable was subjected to normal sodium hydroxide corrosion testing, as defined in this specification, against infiltration of the sodium hydroxide solution between the adhesive layer and the polypropylene (PP) or Mylar layers.

U.S. Patent No. 3,790,694 (Example 8 in

Table II) describes a polypropylene layer which is bonded to a metal strip. This patent does not prescribe a specific adhesive. Because ethylene acrylic acid (EAA) copolymer is the best known adhesive in the industry today, it has been found

that adhesive tapes according to this patent gave results similar to those in U.S. Patent No. 3,325,589. In the patent, a jacket, a shield and composite tapes are applied together during extrusion of the cable jacket. Since the thermoplastic coatings are applied to the shield and the composite tapes above their melting point in order to produce an adhesive connection, these are damaged a priori. The problem of damage to the shielding tape was also not addressed in the cited patent. The US Pat. Nos. 3,325,589 and 3,790,694 relate to a heat-resistant core winding (thermal barrier) or to a filled cable.

US Pat. No. 3,321,572 (Example 8 in Table II) describes metal shielding tapes in which the metal strip is provided with a coating of a polymer resin which is arranged on at least one side and is deformed at an elevated temperature resists. However, these shielding tapes did not meet the requirements regarding the adhesiveness. With these tapes, it was found that the corrosion was not limited to the exposed edge of the metal strip due to the infiltration of the corrosion-causing agents between the layer and the metal strips.

In U.S. Patent No. 3,484,539 the adhesiveness of a weldable layer, e.g. Made of polyvinyl chloride or a polymer that resists deformation at a cable manufacturing temperature, but is not properly connected to the metal strip and is therefore susceptible to corrosion if the cable jacket is damaged.

None of the cited patents show or suggest the use of a non-deformable layer in a shielding tape to prevent damage to the layer during the manufacture, installation, and maintenance of the cable. Furthermore, none of the polymeric layers described in the cited patents meet the requirements with regard to the flat connection, the adhesion and the deformation resistance in order to achieve a satisfactory corrosion resistance of the shielding tape by restricting the corrosion to the exposed metal edges.

Although the composite cables have an increased resistance to the penetration of moisture into the cable core and a greater mechanical strength, some problems have also arisen with regard to the termination and connection of the cables. In particular, it is difficult to separate the jacket from the shielding tape to make an electrical connection with the tape. While it is possible to terminate and connect composite cables without separating the jacket from the shielding tape, it has been found that the quality of the electrical connections is not as good as in those cases where the jacket is removed. Furthermore, the electrical properties of the connection to the shielding tape change less with time than the connections to the shielding tape and the connected sheath of the electrical cables.

The aim of the present invention is to provide a corrosion-resistant shielding tape for cables which does not have the disadvantages mentioned.

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This aim is achieved according to the invention with the characterizing features of patent claim 1.

It is advantageous if an adhesive, weldable layer of thermoplastic polymer resin is applied to the other side of the metal strip, the adhesive force of the adhesive bond between the metal strip and the adhesive, weldable layer after curing over seven days in deionized water at a temperature of 70 ° C is 1.0 kg / 2.54 cm and if a second deformation-resistant layer of polymer resin adheres to the other side of the metal strip, which has a deformation temperature of at least 130 ° C, the adhesive force of the adhesive bond between the metal strip and the first adhesive, weldable layer after curing for seven days a deionized water with a temperature of 70 ° C is 1.0 / 2.54 cm.

Exemplary embodiments of the subject matter of the invention are explained in more detail below with reference to the drawings, in which the same reference numerals represent the same, corresponding materials and parts in the various figures. Show it:

1 shows a cross section through part of an embodiment of a shielding tape according to the invention,

2-9 cross sections through further embodiments of shielding tapes,

10 shows a cross section through a known power cable with insulated conductors, a plastic-coated metal shield and an outer plastic sheath, and

Fig. 11 is an oblique view of an end of a telephone cable with a plurality of pairs of conductors in the core, a plastic-coated metal shield and an outer plastic jacket.

It is noted that the term "metal strip" as used herein means a relatively thin layer of any metal that has good electrical or mechanical properties.

The term "firmly bonded" mentioned in this description means that the path of the corrosion attack on the exposed metal edges of the shielding tape is by chemical and / or mechanical connection of the deformation-resistant layers to the metal strip, either directly or indirectly with an adhesive layer, or by connecting one adhesive, weldable layer is bounded directly with the metal strip to prevent significant splitting between the layers of the deformable and adhesive, weldable layers of metal strips and the exposure of the corrosive conditions and the resulting forces exerted by the metal corrosion products.

The term “adhesive layer” is to be understood as a layer made of a polymer resin that has good composite properties with regard to the metal strip and deformation-resistant layers as well as plastic layers of the electrical cable.

“Weldable layer” means a layer made of thermoplastic polymer resin with a welding temperature of 121 ° C. or lower and preferably 110 ° C. or lower, the layer itself sealing slightly or other polymer resins, for example those materials which form the outer plastic sheath of a cable.

“Adhesive, weldable layer” is understood to mean a layer made of a thermoplastic polymer resin, which has good bonding properties with metal as well as well with adhesive and weldable layers.

is weldable, which are directly connected to the metal strip.

“Deformation-resistant layer” is understood to mean a layer made of a polymer resin that resists penetration and / or abrasion at a deformation temperature of at least 130 ° C. and normal pressures during cable production, laying and / or service work.

1 shows a corrosion-resistant shielding tape 10 for a cable with a metal strip 12 and a deformation-resistant layer 14 made of a polymeric resin material, for example of 50% by weight polypropylene and 50% by weight ethylene / acrylic acid copolymer, which is solid is applied to one side of the metal strip 12. In order to improve the corrosion protection for the metal strip 12, the shielding tape 10 in cable constructions should be provided with an outer plastic jacket which is made of an adhesive mixture which is firmly connected to the metal strip 12 on the side opposite the layer 14.

FIG. 2 shows another shielding tape 20 for a cable, with a deformation-resistant layer 24, which corresponds to the layer 14 according to FIG. 1 and is firmly connected to the metal strip 12. A layer 25 is fixedly attached to the opposite side of the strip 12 and can be a deformation-resistant layer and the same as the layer 24, or it can be an adhesive, weldable layer, which consists of a copolymer of ethylene / acrylic acid.

3 shows a further shielding tape 30 for a cable. The metal strip 12 can be provided with a deformation-resistant layer 34, which corresponds to the layer 14 in FIG. 1 and is firmly connected to one side of the metal strip, a weldable layer 36 made of low-density polyethylene being connected to the layer 34. Furthermore, layer 36 may be made from a deformation-resistant layer of a material such as nylon that is not securely bondable to metal strip 12, with sufficient adhesion to provide corrosion protection. Layer 34 may also be an adhesive layer made of a material such as a copolymer of ethylene / acrylic acid. Like the shielding tape 10 according to FIG. 1, the shielding tape 30 should be usable in cable constructions which have an outer plastic jacket which is made from an adhesive mixture, so that corrosion protection for the metal strip 12 is ensured.

4 shows a further shielding band 40 for a cable. There are four possible structures of a shielding tape 40. Layer 45 can be a deformation-resistant layer like layer 14 in FIG. 1 for two of the possible structures, or an adhesive, weldable layer like layer 25 in FIG. 2 for the other two structures . Layer 44 may also be a deformation resistant layer like layer 14 in FIG. 1 when it is firmly and directly bonded to metal strip 12, or it may be an adhesive layer consisting of a copolymer of ethylene / acrylic acid, which in turn serves to firmly connect a deformation-resistant layer 46 to the layer 36 in FIG. 3, which is not firmly and directly connected to the metal strip 12. If layer 44 is a deformation-resistant layer which is firmly connected to metal strip 12, layer 46 can expediently be a weldable layer, such as layer 36 in FIG. 3.

5 shows a further shielding band 50 for a cable. Three possible structures of the band 50 can be provided. First, two non-deformable layers 56 and 57, like layer 36 in FIG.

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which is not firmly and directly connected to the metal strip 12, is firmly connected to the adhesive layers 54 and 55, such as the layer 34 in FIG. 3. Secondly, the two possible structures can have a deformation-resistant layer 55, such as layer 14 in FIG. 1, which is firmly connected to metal strip 12, and a weldable layer 57, such as layer 36 in FIG. 3, can have layer 55 be connected. On the opposite side of the metal strip 12, a deformation-resistant layer 54, such as the layer 14 in FIG. 1, can be firmly and directly connected to the strip 12, and a weldable layer 56, such as the layer 36 in FIG. 3, can be connected to the Layer 54 or, in a different embodiment, a deformation-resistant layer 56, such as layer 36 in FIG. 3, which is not directly connected to metal strip 12, can be firmly connected to an adhesive layer 54, such as layer 34 in FIG. 3, get connected.

FIG. 6 shows a further embodiment of the shielding tape 60 for a cable. A deformation-resistant layer 66, which is similar to layer 36 in FIG. 3, which is not fixed and is directly connected to the metal strip 12, can be firmly connected to the strip 12 via an adhesive layer 64, which corresponds to the layer 34 in FIG. 3 . A weldable layer 68 of a copolymer of ethylene / acrylic acid is connected to layer 66. As with the shielding tapes 10 and 30, the shielding tape 60 should be usable in cable constructions that have an outer jacket made of an adhesive mixture in order to ensure reliable production protection for the metal strip 12.

7 shows a further embodiment of the shielding tape 70 for a cable. The adhesive layer 74, the deformation-resistant layer 76 and a weldable layer 78 are the same as the corresponding layers 64, 66 and 68 in FIG. 6. Layer 75 may be a deformation-resistant layer, such as layer 14 in FIG. 1, or in a modified embodiment, be an adhesive / weldable layer, such as layer 25 in FIG. 2, and be firmly and directly connected to the metal strip 12.

Another shielding band 80 is shown in FIG. The adhesive layer 84, the deformation-resistant layer 86 and the weldable layer 88 are the same as the corresponding layers 64, 66 and 68 in FIG. 6. On the other side of the metal strip 12, a deformation-resistant layer 85, like the layer 14 in FIG 1 may be provided, which is fixedly and directly connected to the strip 12, and a weldable layer 87, such as the layer 36 in FIG. 3, may be connected to the layer 85, or in a modified embodiment, a deformation-resistant layer 3, which is not fixed and directly connected to the strip 12, fixed to the strip 12, with an adhesive layer 85, such as the layer 34 in FIG. 3.

9 shows a shielding tape 90 for a cable. The adhesive layers 94 and 95, the deformation-resistant layers 96 and 97 and the weldable layers 98 and 99 are the same as the corresponding layers 64, 66 and 68 in FIG. 6.

10 and 11, a power cable 100 is shown with three wires and a telephone cable 110 with a plurality of pairs of conductors. The power cable 100 has low resistance conductor cores, which are full or can consist of strands, for example of copper or aluminum, and each with, for example, a sprayed-on plastic coating 102, e.g. Polyvinyl chloride, polyethylene or rubber can be isolated. Filling compounds 103, e.g. made of natural fibers or foam, give a practically circular core, which is surrounded by a shielding tape 104, which may correspond to one of the shielding tapes shown in FIGS. 1-9. The shielding tape 104 is preferably tubular and has an overlapping seam in the longitudinal direction, which is hermetically sealed by welding, the plastic coating of the shielding tape being joined together with the overlap seam during the manufacture of the cable. An outer plastic sheath 105, which normally consists of sprayed-on polyethylene, contains stabilizing agent and carbon black and is expediently connected to the shielding tape 104 over a large area. The telephone cable 110 contains an inner core of a plurality of insulated conductor pairs 111, for example made of plastic-coated copper wire, which are enclosed by a plastic sheath 112, made of, for example, polypropylene or polyethylene terephthalate, which is firmly connected to a binding tape 113. The binding tape is enclosed in a shielding tape 114, which may have one of the embodiments shown in FIGS. 1-9. Like the shielding tape 104 of the power cable 100, the shielding tape 114 is preferably tubular with a hermetically sealed overlap seam. An outer plastic sheath 115, preferably made of polyethylene, is sprayed onto the shielding tape 114 and is preferably connected to it flatly.

The metal strip can have a thickness of 0.005 to 0.64 mm and preferably 0.05 to 0.38 mm. The metal strip is preferably made of aluminum, aluminum alloys, aluminum composite casting. Copper with a modified surface, bronze, lead, magnesium or tin can also be used. In addition, steel, tin-free steel, tin-coated steel, aluminized steel, stainless steel, stainless steel with a modified, copper-coated surface, matt sheet steel, galvanized steel, chrome or chrome-treated steel can be used. These metals can also be surface treated or have conversion coatings.

The deformation-resistant layer can have a thickness of 0.0025 to 0.38 and preferably 0.013 to 0.5 mm. The deformation-resistant layer is expediently made of a polymer resin which has a deformation temperature of at least about 130 ° C and e.g. made of polypropylene, carboxyl, modified polypropylene, polyamides, polyethylene terephthalates, fluoropolymers, 1-4 dimethylpentene polymers, ethylene / propylene copolymers, stereoregular polystyrene, flexible thermo-curing polymer resins, saran or irradiated, carboxyl-modified olefin polymers. The Saran is a registered trademark. These polymer resins can e.g. are mixed with polyethylene, ethylene / ethylene acrylate copolymers, ethylene / vinyl acetate copolymers, carboxyl-modified ethylene polymers, ethylene / acrylic acid copolymers, ionic olefin polymers or chlorinated polyethylenes, provided that the deformation temperature is at least about 130 ° C. Flexible thermosetting polymer resins, e.g. Polyurethanes can also be used as long as the deformation temperature of 130 ° C is reached.

The most preferred materials are blends of olefin polymers. Other preferred materials include polyamides and Saran R.

The adhesive layer can have a thickness of 0.0025 to 0.25 mm and preferably 0.008 to 0.64 mm. Such layers can be made from any thermoplastic polymer resin that firmly bonds the deformable layer to the metal strip. The most preferred materials are copolymers of ethylene and ethylenically unsaturated carboxylic acids

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form a firm adhesive connection with aluminum. The adhesive polymer which is most conveniently used is a normally solid, thermoplastic, ethylene-modified polymer which is modified by means of monomers with reactive car-boxyl acid groups, in particular a copolymer of a major part of ethylene and smaller portions, normally from 1 to 30, preferably from 2 to 20 wt .-% of an ethylenically unsaturated carboxylic acid. Specific examples of such ethylenically unsaturated carboxylic acids, which include mono- and polybasic acids, anhydride acids and partial esters from polybasic acids, are acrylic acid, methacrylic acids, crotonic acids, fumaric acids, maleic acids, itaconic acids, maleic anhydrides, Monomethylmaleate, Monoäthylma- is leate, Monomethylfumarate, Monoäthylfumarate, Tripro-pylene-Glycol-Monomethyl-Ether, Maleatsäure or Ethylene-Glycol-Monophenyl-Etheric maleate. The car bolic acid monomer is preferably composed of a, β-ethylenic, unsaturated mono- and polycarboxylic acids and 2 »anhydride acids with from 3 to 8 carbon atoms per molecule and partial ester of such polycarboxylic acids, in which the acid half has at least one carboxylic acid group and the alcohol half has from one to two carbon atoms. The copolymer may be primarily composed of 25 ethylene and one or more such ethylenically unsaturated acid comonomers or may also contain small amounts of other monomers that are not copolymerizable with ethylene. Thus, the copolymer can contain other copolymerizable monomers including ester 30 and acrylic acid. The comonomers can be used in the copolymers in any manner, e.g. can be combined as random copolymers, as block or sequential copolymers, or as graft copolymers. Such materials and methods for producing the same are already known.

The weldable layer expediently has a thickness of 0.0025 to 0.25 and preferably 0.0076 to 0.25 mm. The weldable layer can e.g. consist of polyethylene, ethylene / ethylene acrylate copolymers, ethylene / vinyl 40-acetate copolymers, carboxyl-modified ethylene polymers with low or high density or mixtures thereof.

The adhesive / weldable layer can have a thickness of 0.0025 to 0.25 and preferably 0.025 to 0.076 mm 45. The adhesive / weldable layer can e.g. consist of carboxyl-modified olefin polymers, ionic olefin polymers, mixtures of carboxyl-modified olefin polymers or mixtures of ionic olefin polymers. 50

The deformation resistance of a layer of a polymer resin is normally measured using a penetrometer. Existing penetrometers are, however, designed for coatings from one or more layers of synthetic resin material with a thickness of 1.52 to 3.17 mm, and the data they provide do not relate to coating thicknesses of cable shields or to temperatures and processes, which are used in the manufacture of cables. As a result, a special penetrometer test was developed to test the ability of 60 relatively thin coatings, i.e. Measure coatings with a thickness of 0.254 mm or thinner on plastic-coated metals in relation to their resistance to deformation at elevated temperatures. The special penetrometer consists of a metal block of 1.68 kg, on which a circular ring was formed. The ring has an outer diameter of 38.1 mm and a thickness of 0.64 mm. The cutting edge of the ring, which matches the

coated shielding tape is connected, is rounded to a radius of 0.79 mm, which exerts a pressure that corresponds to 24.6 g per mm2. The test method consists in placing the sample from the shielding tape on a base, for example on a metal plate, and then inserting it into the penetrometer so that the ring is brought into contact with the coating arranged thereon. An electrical circuit, which is open due to the coating, is connected over the penetrometer and the metal strip of the test piece. The entire unit is then placed in an oven with air circulation and preheated to 218 ° C so that the temperature of the tested shielding tape is raised at a rate of approximately 10 ° C per minute. When the ring penetrates the coating, the electrical circuit is closed and the temperature of the coating, e.g. measured by thermocouple.

This temperature is the deformation temperature for the tested coating. It has been determined that the conditions of this test correspond to the temperatures and pressures that occur during the manufacture of cables and / or during maintenance. It has also been found that the deformation resistant layer has a deformation temperature of at least 130 ° C, and preferably at least about 138 ° C or more, to withstand the temperatures and pressures normally associated with the manufacture of cables and / or maintenance the same occur.

The adhesive effect between the plastic layers and between a plastic layer and the metal strip of a shielding tape described, which meets the requirements for a tight bond, should be at least 0.39 kg / cm and preferably at least about 0.78 kg / cm of the bandwidth after the tested Tape was immersed in deionized water at a temperature of 70 ° C for 7 days. Liability is determined by preparing a plastic sheath 15.24 cm wide, 15.24 cm long and 1.524 mm thick, following the standards of the United States Department of Agriculture PE-200 of Rural Electrifica- tion administration (REA) can be used. A shielding tape of the same dimension, i.e. 15.24 x 15.24 cm. A strip of polyester film 0.0254 mm thick was placed between the shielding tape and the sheath to prevent a flat connection to one end of the sheath, so that a test piece for use in an elongation testing machine was formed. The shielding tape was connected flat to the cast piece, using a die casting press and a casting temperature of 190 ° C. The casting pressure was 0.2 kg / mm2. The heat cycle was composed as follows: 3 minutes to reach the temperature without pressure, 2 minutes under pressure and 5 minutes to cool down to room temperature. After the coating of the shielding tape and the sleeve material had been completed, 2.54 cm wide test pieces were cut for the tests on a test piece cutter. The specimens were tested on a strain test machine for connection strength as follows: the unconnected part of the shielding tape was bent backwards by 180 °, and then the test piece was inserted into the strain testing machine, with the shielding tape in the upper jaw and the molded part from the Sleeve material was arranged in the lower jaw. Thereon a rigid metal plate was placed behind the casting to maintain a peel angle of 180 °, and then the shielding tape became rigid

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separated from the sleeve material at a crosshead speed of 12.7 cm per minute. The force required to separate the shielding tape from the casting was measured as a measure of the adhesive strength. The separation can occur on the common surface between the metal strip and the plastic layer, or between two plastic layers or between the plastic layer and the jacket.

Various shielding tapes made from plastic-coated aluminum were prepared and tested for corrosion resistance. In particular, test pieces from the shielding tape with a size of 5.08 cm x 5.08 cm were first subjected to a simulated coat test, which is described in more detail below, and then immersed in a normal sodium hydroxide (1N NaOH) solution for 24 hours. Bare aluminum spots on the surface of the shielding tape, whose plastic coatings were damaged during the simulated coat test, have corroded. The number of corroded spots, which were easily ascertainable in the test piece from the shielding tape, were counted and noted as a corrosion damage index. A zero index indicates that there are no corrosion spots, while a number indicates the number of corrosion spots found on the test piece. In the case of a shielding tape with poorly bonded plastic coatings, this resulted in total distribution of the metal, with the layers often being separated.

The simulated sheath test was used to simulate the temperature and pressure conditions that normally occur within a cable during and after sheathing to study the effects on cable components. The test is particularly suitable for studying the effect of temperature and pressure conditions on the plastic layer or on plastic-coated shielding tapes. To perform this test, part of a cable approximately 5.0 cm in length was converted to a rectangular shape with flat surfaces. The test was carried out using the following procedure. A test piece made of a cast jacket of approximately 5.08 x 5.08 cm and weighing 13 g and having a thickness of 2.54 mm was heated to a temperature of 218 ° C. in an oven. The jacket was removed from the oven after 6 to 7 minutes and a corrugated shielding tape of 5.08 x 5.08 cm was placed in the jacket within 5 seconds. Thereafter, a wave-shaped packing material made of polyester film, a part of a cable core with a rectangular shape and a weight of 218 g and a weight of 2 kg were successively arranged on the upper part of the shielding tape. Finally, the entire unit was placed on a large 955 g block of aluminum to cool down while the temperature in the interface between the core wrap and the shield was measured by a thermocouple attached to it. The aluminum block serves as a cooling fin and thus serves as a cooling bath after the spray head.

The temperature-time ratio determined in this test corresponds to that which was determined with cables with a large number of line parts during the spraying of the sleeve. In this context, reference is made to the 14th International Wire and Cable Symposium in Atlantic City, New Jersey, 1965, on which occasion lectures by R.C. Mildner, P.C. Woodland, H.A. Walters and G.E. Clock in relation to a new form of a thermal lock for telephone cables have been held.

The thermal stability was determined on test pieces of the coating by means of a special final test.

Two pieces of film with a width of 50.8 mm were brought together into a welding device, for example Sentinel Brand, model 24AS, or a similar device. The temperature of the welding rod was increased in steps of 5 ° C from 88 ° C to a temperature which is sufficient to connect the foils to one another. The temperature at which the foils are connected to one another is noted as the lowest connection temperature. The pause time in seconds for the welding rod corresponds to 26.25 x the film thickness in mm. The air pressure on the welding rod is set at 28 g / mm2.

The effect of fillers on the cable core was tested by means of test pieces made of plastic-coated shielding tapes, in which coatings on both sides petrolatum filling mixtures (Witco 5B) and flux (Witco 4) were exposed at 115.5 ° C for 2 seconds. A percentage swell was calculated on the fill amount selected from the coating in the following manner after the surface thereof was cleaned of any fill mixes. The original weight of the coating was subtracted from the weight of the coating after exposure and this difference was divided by the original weight. This number was multiplied by 100 to get a percentage swelling. The results of this test are recorded in Table IX.

Coated metal test pieces of 50 x 150 mm were selected in a connector stability test. Then two Griplok connectors were attached to each longitudinal end of the test pieces. The original resistance in milliohms was measured across the connectors using a Kelvin bridge. The examples were then subjected to 50 temperature sequences from -40 ° C to + 60 ° C, each sequence lasting eight hours, after which the resistance was measured again. The results of these tests are shown in Table X.

In a test of the bond strength and flexural strength of the sleeve, a composite gas pipe was made on a cable wrap machine using corrugated laminate lengths. The laminates were oriented so that the multi-layer coated side touched the molded sleeve. Examples of the tube were then collected for detection to determine the sleeve's bond strength and flexural strength. The results of these tests are shown in Table XII.

The following additional test methods were used:

1. The physical properties of the coating were determined in accordance with the ASTM D-638 standard.

2. Elmensdorf wear was measured according to ASTM D-1922.

3. The melt index was measured according to ASTM D-1238 standards.

Representative examples of the present invention as well as deformation temperatures and corrosion index measurement results are shown in Table I. The examples were formed by spraying the plastic layers each about 0.025 mm thick, which were then laminated with a hot metal strip at a temperature of about 190 ° C.

Compound cables, which contained these test pieces, were tested on commercially available machines for the production of cables

10th

15

20th

25th

30th

35

40

45

50

55

60

65

638923

and manufactured under normal process conditions.

The Deformation Strength Penetrometer Test was used to determine the Deformation Temperature.

Examples 8-11 of Table I show the use of these three component mixtures as the core layer.

Example 12 shows the use of a mixture of four components as the core layer.

In Example 13, the lower limit for the deformation temperature of a mixture of polyethylene with polypropylene is recorded at about 130 ° C.

Example 14 defines the use of an adhesive sleeve to determine the usefulness of a metal coated only on one side according to FIGS. 1, 3 and 6. is

Example 15 shows an embodiment in which polypropylene is used as a coating. An EAA-PP mixture is used as the second adhesive layer in order to connect the deformation-resistant layer to a first adhesive layer EAA. A second EAA-PP mixed layer and a weldable layer of EAA can be successfully applied to the PP layer to provide a low temperature seal.

Examples 16-18 are comparable examples. However, the composition of the mixture in the deformation-resistant layer was only chosen where it was not sufficient to obtain a deformation temperature of 130 ° C.

Example 19 represents a special mixture in the deformation-resistant layer, which falls within the desired range 30 of the deformation temperature and the corrosion index.

Example 20 shows a functional example with copper. Since copper degrades an EAA coating in the presence of moisture, a copper stabilizer, OABH, i.e. oxalic acid to benzylidene hydrazide located at 35 EAA.

In Example 21, a functional example with ionomer (Surlyn 1652.11% MAA) is used as the metal adhesive layer. Surlyn is a registered trademark.

Example 22 shows a functional example with an EAA-40 polyethylene mixture as the metal adhesive layer.

Examples 23-25 show functional examples with cross-linked coatings, which are unusual in that they retain their connectivity, their ability to be terminated and their ability to protect against corrosion after irradiation.

Examples 26-27 show functional examples with saran as the heat deformation layer. These structures are not shown in the drawings. As in Example 15, a second adhesive can be made from such a

Mixture or a suitable polymer can be used to connect a heat deformation layer to metal. The basic structures would thus be: metal / adhesive layer / second adhesive layer / deformation-resistant layer, metal / adhesive layer / second adhesive layer / ss deformation-resistant layer / weldable layer (EVA),

or metal / adhesive layer / second adhesive layer (mixture) / deformation-resistant layer / second adhesive layer (mixture) / weldable layer.

A comparative analysis of Tables I and 11 shows the 60 damage which is exerted on a plastic-coated shielding tape of the existing type, measured by the number of corrosion spots, in a range of 25 cm2. Furthermore, the need for a deformation-resistant layer with a deformation temperature 65 of at least 130 ° C. and a solid composite is illustrated in order to prevent the occurrence of bare spots on the surface of the strip and the remaining corrosion potential.

Examples 9-11 in Table II show the damage to lower melting point coatings on metal that can occur due to a deformation-resistant layer. Without a close connection between a deformation-resistant layer and a metal composite layer, or with connections between the two, which are sensitive to water, corrosion can occur on the damage in the adhesive coating on the metal.

Example 12 shows the non-functionality of this design for corrosion protection.

Example 13 shows the need for a full bond of the coatings with metal.

Tables III and IV show the original bond strengths as well as those after aging for seven days in deionized water at 70 ° C. Two sets of numbers are given in Table III,

because the multi-layer coatings do not necessarily have to fail at the metal interface with an adjacent polymer layer during the bond strength tests. If a metallic composite exceeds that of the different polymer layers with one another, then a composite breakdown occurs at the weakest common surface. These example numbers refer to those in Tables I and II, in which the detailed shielding tape designs are shown. The lowest bond strength is 0.39 kg / cm, regardless of whether the bond strength relates to a metal / polymer layer composite or to a polymer layer / polymer layer composite. In the former case, the corrosion resistance and the mechanical performance below the minimum bond strength will be ineffective. In the second case, the ability to resist handling without stacking also does not want to be impaired below this minimum bond strength.

Table III shows that the reasonable selection of the types and ratios of the polymer mixtures results in a bond between the metal strip and the adhesive layers, which bond is stronger than the interlayer bond of the other layers of polymer resin, with a minimum bond strength of 0.39 kg / cm is present between the polymeric coating and the polymeric coating composite.

Tables V and VI show that the multi-layer coatings provide an improved,

last tensile strength as well as elongation and tear strength compared to existing coatings. The example numbers relate only to the improved coating structures according to Table I and not to the coated metal structures.

Tables VII and VIII show actual cable data in which the cables use different shielding tapes, which are shown in Tables I and II. The same sample numbers are used.

Table IX shows that the coatings described above have increased resistance to adverse effects from fill and flood mixes. This advantage also advantageously extends the life of the filled cables.

Table X shows that the connector stability over coated metal is improved with an improved coating because the increase in resistance across the output is smaller.

Table XI shows that the dielectric strength and permeation resistance are improved with the new coating. The electrical strength

638923

10th

The new coating can be used to advantage in filled cable versions to eliminate the normal electrical insulation wrapped around the core. The reduced permeation ratio can lead to an improvement in corrosion resistance.

The bond strength according to the figures in Table XII indicates the level of the interlayer bond of the multilayer test pieces. These composite values are approximately half as large as those of the conventional test pieces (example 5 according to Table II). The breakdown of the intermediate layer, however, provides a device for controlling the level of the bond between the polymer layers of the shielding tape and the sleeve, i.e. that the bond is strong enough to provide good mechanical properties, while at the same time the sleeve is at

Connect can be easily stripped. Furthermore, at least the adhesive layer of the multilayer coating on the metal strip remains undamaged so that permanent corrosion protection is created;

5

The bending values are astonishing because the samples with several layers with half bond strength have bending properties which correspond to those of the control test piece. These results tend to suggest that the bendability has a moderately high bond strength, but the ability to relieve stress may be more important. The film, which consists of several layers, serves as a device for relieving the tension due to the smaller interface adhesion.

Table I

Described embodiments

Example no. Layer construction

Deformation temperature ° C

Corrosion index

] (4)

EAA (1) / A1 (EAA (l) / 50% EAA (l) -50% PP / EAA (1)

144

0

2 <4>

EAA (1) / A1 / EAA (l) / 40% EAA (l) -60% PP / EAA (1)

164

0

3 *

EAA (1) / A1 / EAA (l) / 30% EAA (l) -70% PP / EAA (1)

164

0

4 (4)

EAA (1) / A1 / EAA (l) / 50% LDPE-50% PP / EAA (1)

164

0

5 <4>

EAA (1) / A1 / EAA (1) / 100% nylon / EAA (1)

> 199

0

6 <3)

50% EAA (2) -50% PP / Al / 50% EAA (2) -50% PP

166

0

7 (4)

EAA (1) / TPS / EAA (l) / 50% HDPE-50% PP / EAA (1)

163

0

8 <4>

EAA (1) / A1 / EAA (l) / 34% HDPE (l) -64% PP-2% LDPE / EAA (1)

163

0

9 (4)

EAA (1) / A1 / EAA (l) / 39% HDPE (l) -59% PP-2% LDPE / EAA (1)

160

0

10 (4)

EAA (1) / A1 / EAA (l) / 44% HDPE (l) -54% PP-2% LDPE / EAA (1)

154

0

11 (4)

EAA (1) / A1 / EAA (l) / 49% HDPE (l) -49% PP -2% LDPE / EAA (1)

151

0

12 <4>

EAA (1) / A1 / EAA (1) / 19% HDPE (1) -19% EAA (l) -2% LDPE / 60% PP / EAA 158

0

13 (3)

EAA (1) / A1 / EAA (l) / 70% HDPE- 30% PP

136

0

14 (4)

0.254 mm sleeve made of EAA (1) / A1 / EAA (l) / 35% HDPE (1) 65% PP / EAA (1)

163

0

15 (3)

EAA (1) / A1 / EAA (l) / 50% EAA (l) -50% PP / PP

164

0

16 *

EAA (1) / A1 / EAA (l) / 90% HDPE-10% PP / EAA (1)

124

94

17 *

EAA (1) / A1 / EAA (l) / 80% HDPE-20% PP / EAA (1)

128

86

18 *

EAA (1) / A1 / EAA (l) / 70% EAA (l) -30% PP / EAA (1)

111

35

19 (4)

EAA (1) / A1 / EAA (l) / 60% EAA (l) -40% PP / EAA (1)

131

7

20 <4)

EAA (3) / Cu / EAA (3) / Nylon / EAA (1)

> 199

0

21 (4)

ionomer / Al / ionomer / 50% PP-50% HDPE

154

0

22 (3)

70% EAA (l) -30% HDPE / Al / 70% EAA (l) -30% HDPE / 50% PP-50% HDPE

163

0

23®

EAA (1) / A1 / EAA (1) (irradiated with 10 megarads)

> 210

0

24®

EAA (1) / A1 / EAA (1) (irradiated with 10 megarads)

> 210

0

25 (2)

EAA (1) / A1 / EAA (1) / LDPE (irradiated with 5 megarads)

> 210

0

26 <4>

EAA (1) / A1 / EAA (l) / 50% EVA-50% EAA / Saran

160

0

27 (4)

EAA (1) / A1 / EAA (1) / EVA / Saran / EVA / EAA (1)

161

0

* Examples prepared for comparison

(l) - All mixture percentages by weight

® - Examples made by extrusion coating

(3) _ Made by coating blown films

(4) - Made by coating cast foils

Al - aluminum layer (0.203 mm thick) for electrical purposes

EAA (1) - ethylene / acrylic acid copolymer layer, 8% by weight acrylic acid

EAA (2) - ethylene / acrylic acid copolymer layer, 12% by weight acrylic acid

EAA (3) - ethylene / acrylic acid copolymer layer, 8% by weight acrylic acid with 0.1% copper stabilizer PP - polypropylene, melt flow 9.0, density 0.905 PP (1) - polypropylene, melt flow 7.0, density 0.908

HDPE - high density polyethylene, melt index 3.6-4.4, density 0.963-0.967 HDPE (1) - high density polyethylene, melt index 5.0, density 0.964 LDPE - low density polyethylene, melt index 1.95, density 0.919 nylon - nylon 6 layer

EVA - ethylene / vinyl acetate copolymer - 28% by weight vinyl acetate TPS - tin-plated steel layer, 0.152 mm thick Cu - copper layer, 0.127 mm thick

All layer interfaces are indicated by the inclined symbol /.

Table II

Known embodiments

Example No.

Layer construction

Deformation temperature ° C

Corrosion index

1 (5)

LDPE / Adh (1) / AI / Adh (1) / LDPE

US 3,809,603

106

77

2nd

Three-component copolymer / Al / three-component copolymer

US 3,849,591

108

60

3 (2)

LDPE / EAA (1) / Al / EAA (1)

US 3,856,756

106

92

4 (2)

HDPE / EAA (1) / A1 / EAA (1)

US 3,507,978

122

14

5 (2)

EAA (1) / Al / EAA (1)

US 3,233,036

102

99

US 3,795,540

6 (5>

EVA / Ionomer / Al / Ionomer / EVA

** Ishikawa Valley.

112

39

US 3,959,605

7 (4)

EAA (2) / Al / EAA (2)

US 3,868,433

102

*

8 (4)

PP / Al / PP

US 3,790,694

163

*

US 3,379,824

US 3,622,683

9 <4)

0.127mm PP / EAA (1) / Al / EAA (1)

US 3,325,589

163

41

10 (4)

0.025mm Mylar / EAA (1) / Al / EAA (1)

US 3,325,589

> 209

36

11 (4)

0.0762mm Mylar / EAA (1) / A1 / EEA (1)

US 3,325,589

> 209

38

12 (4)

LDPE / Al / LDPE

GB 886,417

106

*

13 (4)

Mylar / Al / EAA (1)

US 3,321,572

> 209;

*

* - Metal completely released during the test: insufficient corrosion resistance

** - H. Ishikawa, et al. "New process for the production of polyethylene-coated cables from laminated aluminum", 21st International Wire and Cable Symposium, Atlantic City, New Jersey, 1972, page 153 AI - aluminum layer for electrical purposes, 0.203 mm thick LDPE - low-density polyethylene layer

Adh (1) - Thermoplastic adhesive layer according to US Pat. No. 3,809,603 three-component copolymer - ethylene, vinyl acetate and methacrylate or glycidyl acrylate layer EAA (l) - ethylene / acrylic acid (disordered) copolymer layer

HDPE - high density polyethylene layer, melt index 6.0 - 9.0, density 0.962 - 0.966 EVA - ethylene / vinyl acetate copolymer layer

Ionomer - ethylene / methacrylic acid copolymer layer, in which the acid is partially neutralized by metal ions. •

EAA (2) - ethylene / acrylic acid graft copolymer layer Mylar - polyethylene terephthalate

- Made by extrusion coating.

(3) - Made by coating blown films.

(4) - Made by coating cast films.

'5' - unknown type of coating

638923 12

Table III

Described embodiments

Table I binding strength in kg / 25.4 mm

Example No. regarding metal originally after aging regarding plastic originally after aging

1

7.95

9.08

3.27

4.09

2nd

7.95

9.11

1.04

1.09

3 *

7.95

9.08

0.54

0.68

4th

7.90

8.99

2.60

2.59

5

7.95

9.09

4.63

2.95

6

2.77

2.93

2.81

2.92

7

15.44

12.94

4.27

5.09

8th

6.45

April 6

1.05

1.00

9

6.36

6.18

1.34

1.36

10th

6.36

6.68

2.36

2.13

11

6.45

6.59

3.13

3.09

12

6.45

6.63

1.34

1.32

13

7.95

8.90

8.40

8.42

14

7.55

8.35

1.07

1.05

15

7.95

8.77

2.31

2.30

16 *

8.95

9.12

8.18

9.54

17 *

8.95

9.17

7.45

6.13

18 *

8.90

9.13

8.72

7.13

19th

8.92

9.15

4.54

4.51

20th

11.20

10.50

4.26

4.28

21st

7.84

7.90

1.43

1.45

22

8.29

9.12

2.90

2.93

23

9.64

10.05

8.45

8.90

24th

6.68

7.53

6.95

6.93

25th

July 8

9.50

4.27

4.31

26

8.40

9.15

1.81

1.78

27th

8.42

9.23

3.86

3.91

* Comparative examples

Table IV Known embodiments

Table II binding strength in kg / 25.4 mm

Example No. regarding metal originally after aging

1

4.31

5.18

2nd

7.18

3.73

3rd

4.27

4.82

4th

6.72

8.30

5

8.00

8.86

6

4.59

6.63

7

2.68

3.72

8th

0

0

9

0.14

0

10th

0.40

0

11

0.50

0

12

0.17

0

Described embodiments

Table V

Table I Example No.

direction

Load in kg / mm2 result last

Extension in%

Elemensdorf wear (gms)

Min.

Final temperature ° C

MD CD MD CD

0.96 0.97 0.99 0.95

2.68 2.16 2.57 2.22

580 555 605 656

634 672 525 717

113 113

13 638923

Table V (continued)

Described embodiments

Table I Example No.

direction

Load in kg / mm2 result last

Extension in%

Elemensdorf wear (gms)

Min.

Final temperature ° C

4th

MD

1.32

2.58

685

307

113

CD

1.30

2.36

685

442

5

MD

1.70

4.65

600

166

110

CD

1.80

4.56

540

150

8th

MD

1.38

2.82

770

480

104

CD

1.32

2.58

795

576

9

MD

1.37

2.64

775

295

104

CD

1.36

2.58

755

499

10th

MD

1.41

2.65

695

262

107

CD

1.35

2.49

750

486

11

MD

1.32

2.60

760

352

110

CD

1.29

2.50

800

538

12

MD

1.38

2.84

715

416

110

CD

1.27

2.47

740

589

Table VI

Known embodiments

Table II Example No.

direction

Load kg / mm2 Result last

Extension in%

Elmensdorf wear (gms)

l

MD

1.13

1.90

300

170

CD

1.06

1.58

450

190

5

MD

0.74

1.79

450

244

CD

0.71

1.83

560

308

Load and extension: ASTM D-882 MD - machine direction CD - cross-machine direction Elmensdorf wear: ASTM D-1922

Table VII

Actual cable data in the described exemplary embodiments

Table I

Cable size

Shell melting temperature ° C

Running speed in m / min.

Corrosion index

Example No.

2nd

100 pr, 22 AWG air core

221

18.0

0

3rd

100 pr, 22 AWG air core

221

18.0

0

5

150pr, 24 AWG air core

218

15.2

0

5

75 pr, 24 AWG filled core

232

30.5

0

9

100 pr, 22 AWG air core

235

24.4

0

Table VIII

Actual cable data, in known exemplary embodiments

Tables

Cable size

Shell melting temperature ° C

Running speed in m / min.

Corrosion index

Example No.

3rd

25 pr, 22 AWG air core

199

30.5

49

4th

100 pr, 22 AWG air core

199

18.0

36

5

25 pr, 22 AWG air core

199

30.5

97

5

150 pr, 22 AWG air core

218

15.2

76

5

75 pr, 24 AWG filled core

232

30.5

22

5

100 pr, 22 AWG air core

221

18.0

78

638 923

14

Table IX

Filling material and flood resistance

Coated metal structure (A)

Percentage swell (B)

Filling material (C) Flooding agent (D)

EAA (l) / 50% EAA (l) -50% PP / EAA (1) / A1 / 5.2

EAA (1) 50% EAA (l) -50% PP / EAA (1)

EAA (l) / 40% EAA (l) -60% PP / EAA (1) / A1 / 5.2

EAA (l) / 40% EAA (l) -60% PP / EAA (1)

EAA (l) / 50% HDPE-50% PP / EAA (1) / A1 / 5.0

EAA (l) / 50% HDPE-50% PP / EAA

Example 5 (Table II) 10.5

10.2 11.1 10.1 13.8

(A) Description of the materials, see Table I

(B) Weight gain after contact with the fill and flood material for 2 seconds at 115.5 ° C

(C) Mixture of 92% petrolatum and 8% polyethylene

(D) Mixture of 75% petrolatum and 25% atactic polypropylene

Table X

Stability of the connectors

Table I

Resistance in milliohms (1)

Example No.

originally after heat treatment (2)

2nd

0.6663

1,187

10th

0.6912

1,702

18th

0.7353

1.7825

5 (3)

0.6750

2,727

1. Two connectors were attached to a 50x140mm sample of coated metal with resistance measured using a Kelvin bridge.

2. Resistance to 50 temperature sequences from -40 to + 60 ° C, each lasting eight hours.

3. Example No. 5 from Table II.

Table XI coating properties

1 Example 10, Table I

2 Example 5, Table II

Exemplary embodiments described 1

Known embodiments 2

Table XII

40 connection strength of the casing and the bending property of a gas pipe with connected sleeve (3)

Shield laminate

Dielectric strength, 1360 1100

Kilovolts / cm

permeability

N2, cc-mil / 24 hours / 100 334 525

inVAtm

O2, cc-mil / 24h / 100 1130 1580

inVAtm

H2O, g-mil-24 / hour / 100 0.74 1.28

inVAtm

45

Sleeve connection strength in kg / cm width

Bending property (1), cycles

R / D (2) from

50

Example 10 - Table I 1.96 Example 5 - Table II 3.46

16 13

30 22

40 38

(1) Number of bends required backwards around the specified mandrel to create a break in the shield. 1 cycle = 2 sheets

(2) R / D = radius of the mandrel / diameter of the tube

(3) The thickness of the sleeve was about 0.152 cm. The tubes were filled with lead bullets to provide internal support.

The deformation-resistant layer of polymer resin can occur normally during the manufacture and service of cables on penetration and / or abrasion on the exposed metal.

prevent streaks at temperatures and pressures which

B

1 sheet of drawings

Claims (21)

638923 2nd PATENT CLAIMS 1. Corrosion-resistant shielding tape for cables, characterized in that it is a metal strip, a first adhesive layer, which is composed of a copolymer of ethylene and from 2 to 20%, based on the weight of the copolymer, an ethylenically unsaturated carboxylic acid, and adheres directly to one side of the metal strip, and has a first deformation-resistant layer of polymer resin, this layer adhering to the first adhesive layer, which first deformation-resistant layer has a deformation temperature of at least 130 ° C., the adhesive force of the adhesive bond between the metal strip and the first adhesive layer and between the first adhesive layer and the first deformation-resistant layer after curing for seven days in deionized water at a temperature of 70 ° C., 1.0 kg / 2.54 cm. 2. Tape according to claim 1, characterized in that an adhesive, weldable layer made of thermoplastic polymer resin is applied to the other side of the metal strip, the adhesive force of the adhesive bond between the metal strip and the adhesive, weldable layer after curing over seven days in deionized water at a temperature of 70 ° C is 1.0 kg / 2.54 cm. 3. Tape according to claim 1, characterized in that a second deformation-resistant layer of polymer resin adheres to the other side of the metal strip, which has a deformation temperature of at least 130 ° C, the adhesive force of the adhesive bond between the metal strip and the first adhesive, weldable layer after curing for seven days in deionized water at a temperature of 70 ° C is 1.0 kg / 2.54 cm. 4. Tape according to claim 3, characterized in that a weldable layer made of thermoplastic polymer resin is applied to the side of the second deformation-resistant layer which faces away from the side to which the metal strip adheres. 5. Tape according to claim 3, characterized in that a second adhesive layer, which is composed of a copolymer of ethylene and 2-20 wt .-% of an ethylenically unsaturated carboxylic acid, is arranged between the second deformation-resistant layer and the metal strip and directly on Metal strip adheres, the adhesive force of the adhesive bond between the metal strip and the second adhesive layer and between the second adhesive layer and the second deformation-resistant layer after curing for seven days in deionized water at a temperature of 70 ° 1.0 kg / 2.54 cm. 6. Tape according to claim 1, characterized in that a weldable layer of thermoplastic polymer resin is applied to the side of the first deformation-resistant layer, which faces away from the side to which the first adhesive layer adheres. 7. Band according to claim 6, characterized in that a second deformation-resistant layer of polymer resin adheres to the other side of the metal strip, which has a deformation temperature of at least 130 ° C. 8. Tape according to claim 6, characterized in that an adhesive, weldable layer made of thermoplastic polymer resin is applied to the other side of the metal strip. 9. Tape according to claim 7, characterized in that a weldable layer made of thermoplastic polymer resin is applied to the side of the second deformation-resistant layer which faces away from the side to which the metal strip adheres. 10. Tape according to claim 5, characterized in that a weldable layer of thermoplastic polymer resin is applied to the side of the first deformation-resistant layer, which faces away from the side to which the first adhesive layer adheres. 11. Band according to claim 10, characterized in that a weldable layer of thermoplastic polymer resin is applied to the side of the second deformation-resistant layer, which faces away from the side to which the second adhesive layer adheres. 12. Tape according to one of claims 1-11, characterized in that the maximum extensibility in the transverse direction of several layers of the polymer resin including the deformation-resistant layer on one side of the metal strip determined according to the ASTM D-882 standard is 2 kg / mm2. 13. Tape according to claim 12, characterized in that the layers have an elongation at break of at least 500%. 14. Tape according to one of the preceding claims, characterized in that the percentage increase in weight of the tape is less than 6% after it has been mixed for 2 seconds with a mixture of 92% by weight petroleum jelly and 8% by weight polyethylene at a temperature of 115 , 5 ° C and the excess mixture has been removed. 15. Tape according to one of the preceding claims, characterized in that the electrical resistance of a tape with a length of 14.0 mm, a width of 5.0 mm and two connectors connected to the longitudinal ends is less than 2 milliohms after 50 times has been exposed to a temperature range of -40 ° C to + 60 ° C for eight hours. 16. Band according to one of the preceding claims, characterized in that the metal strip consists of aluminum, copper, bronze, tin-free steel, tinplate or copper-clad stainless steel. 17. Tape according to claim 1, characterized in that the first adhesive layer is deformable at a radiation temperature of at least 130 ° C. 18. Tape according to claim 1, characterized in that the first adhesive layer has a deformation temperature of> 210 ° C over an effective duration after ionizing high-power radiation. 19. Use of the shielding tape according to claim 1 for the insulation of an electrical cable, which has at least one insulated conductor as a cable core, for protection against corrosion. 20. Use according to claim 19, characterized in that the first adhesive layer contains irregular ethylene copolymer and gerylic acid. 21. Use according to claim 19, characterized in that the deformation-resistant layer consists of a mixture of 10 to 60 wt .-% polypropylene and 50-90 wt .-% polyethylene.