United States Patent (19)
`Aitken et al.
`
`US005427643A
`Patent Number:
`11
`45) Date of Patent:
`
`5,427,643
`Jun. 27, 1995
`
`54 METHOD OF USING ANADHESIVETAPE
`FOR OVERCOATING SPLCES IN
`POLYMER COATED METAL TAPES AND
`METHOD OF USNG THE SAME
`
`75) Inventors: Hal G. S. Aitken, Pickering; Richard
`W. Demianyk, Winnipeg, both of
`Canada
`
`73) Assignee: Alcatel Canada Wire Inc., Ontario,
`Canada
`
`21 Appl. No.: 178,048
`
`Jan. 6, 1994
`22 Filed:
`(30)
`Foreign Application Priority Data
`Feb. 2, 1993 CA) Canada ................................. 2088619
`
`51) Int. Cl. .............................................. B29C 65/02
`52 U.S.C. .............................. 156/304.5; 156/304.6;
`156/157; 428/40; 428/355
`58) Field of Search ................. 428/40, 343, 344, 352,
`428/353, 354, 355, 356; 156/304.5, 304.6, 305,
`306.6, 307.7, 157; 228/171,203
`
`56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`4,319,938 3/1982 Vives .................................... 156/49
`4,358,494 11/1982 Akimoto et al.
`... 428/343 X
`4,545,843 10/1985 Bray ................
`... 428/354 X
`4,699,824 10/1987 Pufahl .........
`... 428/337 X
`4,759,816 7/1988 Kasper et al. .................. 428/352 X
`Primary Examiner-Daniel R. Zirker
`Attorney, Agent, or Firm-Ware, Fressola, Van der
`Sluys & Adolphson
`ABSTRACT
`(57
`An adhesive tape is provided for overcoating splices in
`polymer coated metal tapes, which comprises a plastic
`film that serves as recoating material, a layer of adhe
`sive applied to one face of this film and covered by a
`releasing tape which is peeled-off when required to
`expose the adhesive tape which is then applied onto the
`area of the splice to overcoat the same. The adhesive is
`crosslinkable by application of heat and is crosslinked
`during a subsequent cable jacketing operation, thereby
`forming a strong bond between the non-coated metal
`tape in the splice area and the recoating plastic film.
`
`11 Claims, 2 Drawing Sheets
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`/O
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`U.S. Patent
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`June 27, 1995
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`U.S. Patent
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`June 27, 1995
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`U.S. Patent
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`June 27, 1995
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`Sheet 2 of 2
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`U.S. Patent
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`June 27, 1995
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`Sheet 2 of 2
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`5,427,643
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`1.
`
`METHOD OF USING ANADHESIVE TAPE FOR
`OVERCOATING SPLCES IN POLYMER COATED
`METAL TAPES AND METHOD OF USING THE
`SAME
`
`5
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`5,427,643
`2
`(b) a layer of adhesive applied to one face of said
`plastic film which will adhere to a metal surface to
`be recoated, and which is crosslinkable by applica
`tion of heat; and
`(c) a releasing tape covering the adhesive layer with
`out forming a strong bond to the adhesive during
`storage and which can be readily pealed-off from
`the adhesive when required.
`The method for recoating splices in polymer coated
`metal tapes comprises removing the releasing tape from
`the adhesive tape; applying the so uncovered adhesive
`surface of the tape against the splice portion of the metal
`tape having no polymer coating thereon; and crosslink
`ing the adhesive by application of heat.
`The invention will be fully understood when refer
`ence is made to the following detailed description taken
`in conjunction with the accompanying drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a perspective view of the structure of the
`adhesive tape of the present invention used for over
`coating of splices;
`FIG. 2 is a perspective view of a spliced metal tape to
`be recoated and two pieces of adhesive tape about to be
`used to coat the spliced metal tape;
`FIG. 3 is a perspective view of the adhesive tape
`being installed on the spliced metal tape to be recoated;
`FIG. 4 is a perspective view of a cable core sur
`rounded by the recoated metal tape following the cor
`rugation step; and
`FIG. 5 is a cross-sectional view of a completed cable
`with an extruded plastic jacket surrounding the re
`coated metal tape.
`DETAILED DESCRIPTION OF THE
`INVENTION
`In FIG. 1 of the drawings, the adhesive tape 10 for
`overcoating splices in polymer coated metal tapes is
`illustrated. It comprises a recoating tape or film 12, a
`layer of adhesive 14 and a releasing tape or release sheet
`16 such as the silicone coated paper tape. The silicone
`coat of this tape 16 is applied against the adhesive 14 so
`as to protect the same, but without forming a very
`strong bond with the adhesive during storage.
`When used, the release tape 16 is first peeled off as
`shown in FIG. 2 and discarded and the uncovered sur
`faces of the adhesive 14 are applied against non-coated
`metal splice areas 18 on both sides of a polymer coated
`metal tape material 20. The recoating tape 10 adheres to
`the polymer coated metal tape material 20 with the
`recoating tape 10 thereby covering the areas 18 as
`shown in FIG. 3. The non-coated metal splice areas 18
`could include a weld 21. Then, as shown in FIG. 4, the
`polymer coated metal tape material 20 with the recoat
`ing tape 10 thereon continues to proceed through nor
`mal shielding operations where it is corrugated around
`a cable core 22 such as a plurality of insulated metal
`conductors 23. The normal shielding process culminates
`in a jacketing operation as shown in FIG. 5 where a
`jacket 24 is extruded around the polymer coated metal
`tape 20 and the recoating tape 10 to provide mechanical
`protection to the completed cable 26. During the jacket
`extrusion, melted thermoplastic material, such as poly
`ethylene, forms the jacket 24 and the heat from the
`melted material causes the adhesive 14 to crosslink
`thereby producing a satisfactory bond between the
`non-coated metal splice area 18 and the recoating tape
`
`BACKGROUND OF THE INVENTION
`This invention relates to the manner in which splices
`in polymer coated metal tapes are recoated. More par
`ticularly, it relates to an adhesive tape for overcoating
`the splices in polymer coated metal tapes and thereby
`recoating the same in the area where the polymer coat
`ing is lost when weld splices are made.
`The use of polymer coated metal tapes in electrical
`15
`cable constructions is well known. For example such
`metal tapes are commonly used as shields in communi
`cation cables and, as such, they are generally known as
`shielding tapes. Plastic coated aluminum tape is prefera
`bly used for this purpose, however plastic coated steel
`tapes or plastic coated copper tapes or combinations of
`various plastic coated metal tapes are also well known.
`A typical manufacturing line for the manufacture of
`tape shielded cable requires a payoff for the tape; a tape
`splicing station when the ends of the individual tapes
`25
`are spliced or joined together, usually by spot welding
`or other butt-jointing techniques; a device to accumu
`late tape, while splicing on a new length of tape is per
`formed; if necessary, a device for corrugating the tape
`which is then passed through a conventional device that
`guides the cable core while having the corrugated tape
`surround the core; and finally the combination is fed to
`an extruder for applying an outer jacket of thermoplas
`tic material, such as polyethylene. Since waterproofing
`is usually required, the core is normally filled with a
`35
`filling compound such as INSOJELL C-3589, which is
`a trade name of a filling compound produced and sup
`plied by Dussek Campbell Limited.
`When plastic coated metal tapes, such as Zetabon
`(trade name of Dow Chemical), are spliced, the original
`plastic coating is removed from the ends to be spliced,
`which ends are then spot welded to one another. Cus
`tomer and industry specifications require that the coat
`ing be restored in the spliced area. The current method
`of restoring the coating is to use an iron-like device to
`45
`melt the recoating tape onto the metal, thereby provid
`ing a heat sealing of the polymer coating to the splice by
`application of heat and pressure. An example of such
`method is disclosed, for example, in U.S. Pat. No.
`4,319,938. Such heat sealing is time consuming and
`50
`requires special heat sealing equipment, resulting in
`additional capital expenditure. It is also greatly depen
`dent on operator's expertise since the amount of heat,
`pressure and time of application are very much a factor
`in the satisfactory recoating and are directly controlled
`by the operator.
`SUMMARY OF THE INVENTION
`To obviate the above problems and to simplify the
`splice overcoating procedure, the present invention
`proposes the use of an adhesive tape that can be directly
`applied to the splice area and provide the repaired re
`coating thereof.
`The adhesive tape for overcoating splices in polymer
`coated metal tapes in accordance with the present in
`65
`vention comprises:
`(a) a plastic film that serves as recoating material for
`the splices;
`
`O
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`30
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`55
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`10
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`5,427,643
`3
`4
`10. The bond passes the delamination requirements of
`(a) providing a polymer coated metal tape with a
`the original coated metal tape.
`non-coated metal splice area;
`(b) providing an adhesive tape for overcoating the
`The recoating material or film 12 can be any thermo
`plastic polymer film that is compatible with the adhe
`non-coated metal splice area of the polymer coated
`sive 14, i.e. will not cause premature degradation of the 5
`metal tape, the adhesive tape comprising:
`(i) a plastic film that serves as recoating material for
`adhesive 14 and vice-versa, and will bond to the cable
`the non-coated metal splice area,
`jacket 24 applied subsequent to recoating of the splice.
`(ii) a layer of adhesive applied to one face of said
`The most commonly used material is an ethylene/acry
`plastic film which will adhere to the non-coated
`lic acid (EAA) copolymer film, such as sold under the
`metal splice area to be recoated, and which is
`designation DAF 628 by the Dow Chemical Company.
`crosslinkable by application of heat, and
`Other suitable thermoplastic polymers include, but not
`(iii) a release sheet covering the adhesive layer
`by way of limitation, ethylene vinyl acetate (EVA),
`without forming a strong bond to the adhesive
`polyethylene (PE) and polyvinylchloride (PVC).
`during storage and which can be readily peeled
`The thickness of the recoating film 12 is dependent on
`off from the adhesive when required;
`the application. Thicknesses between 0.0005" and
`(c) removing the release sheet from the adhesive tape
`0.025" (0.01 mm and 0.6 mm) are acceptable. The most
`to provide an uncovered adhesive surface;
`common thickness would be between about 0.001' and
`(d) applying the uncovered adhesive surface of the
`0.004' (0.025 mm and 0.1 mm).
`adhesive tape against the non-coated metal splice
`The adhesive 14 applied to the recoating tape 12 may
`area of the metal tape; and
`20
`be any adhesive that is compatible with the tape 12, has
`(e) crosslinking said adhesive by application of heat.
`the required viscosity when applied to such film 12, is
`2. A method according to claim 1, in which said
`resistant to cable filling and flooding compounds and, of
`cross-linking is effected as a result of a subsequent cable
`course, provides a positive bond to the metallic tape 20
`jacketing operation.
`in the area 18 of the splice. The adhesive 14 must also be 25
`3. A method according to claim 1, in which the poly
`crosslinkable by application of heat. An example of such
`mer coated metal tape is a plastic coated aluminum tape.
`adhesive is TIMMINCO S0984 which is a trade name of
`4. A method according to claim 1, in which the plas
`a self-crosslinking acrylic polymer adhesive supplied by
`tic film that serves as recoating material is a thermoplas
`tic polymer compatible with the adhesive and capable
`Timminco Ltd.
`The releasing tape 16 could comprise any suitable 30
`of being bonded to a cable jacket which is applied sub
`sequent to recoating of the non-coated metal splice area.
`tape that would not form a permanent bond with the
`5. A method according to claim 4, in which said
`adhesive 14 when stored for at least one year. Usually,
`plastic film is an ethylene/acrylic acid copolymer film.
`it would comprise a release paper commonly used for
`6. A method according to claim 4, in which said
`similar applications. For example, it could be formed of
`plastic film is a film selected from the group consisting
`35
`three layers namely, a bleached paper sandwiched be
`of ethylene vinyl acetate, polyethylene and polyvinyl
`tween two layers of polyethylene and one side of which
`chloride.
`is treated with silicone. The silicone treated side is
`7. A method according to claim 1, in which said
`placed against the adhesive surface on the splice recoat
`plastic film has a thickness of between about 0.0005 in
`ing tape so as not to form a strong bond between said
`and 0.025 in (0.01 mm and 0.6 mm).
`adhesive surface and the releasing tape. A good exam
`8. A method according claim 1, in which said plastic
`ple of such releasing paper tape is HP Smith 8024 sup
`film has a thickness of between about 0.001 in and 0.004
`plied by H. P. Smith Company.
`in (0.025 mm and 0.1 mm).
`It will be appreciated that the method of overcoating
`9. A method according to claim 1, in which said
`splices with such recoating adhesive tapes is very sin
`adhesive is resistant to cable filling and flooding con
`45
`ple and efficient and avoids all the previously men
`pounds with which the polymer coated metallic tapes
`tioned disadvantages found in the prior art. It is also
`are used and, when applied, provides a positive bond to
`much faster than the presently used heat sealing
`the metallic tape in the non-coated metal splice area.
`method.
`10. A method according to claim 9, in which said
`It should be understood that the preferred embodi
`adhesive is a self-crosslinking acrylic polymer adhesive.
`50
`ment described above is by no means limitative and that
`11. A method according to claim 1, in which the
`modifications obvious to those skilled in the art can be
`release sheet is formed of three layers comprising a
`made without departing from the spirit of the invention
`layer of bleached paper sandwiched between two layers
`and the scope of the following claims.
`of polyethylene, with one side thereof being treated
`What is claimed is:
`with silicone, said side treated with silicone being ap
`1. A method for recoating splices in polymer coated
`plied against the adhesive surface.
`metal tapes, which comprises the steps of:
`
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`UNITED STATES PATENT ANDTRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`PATENT NO. : 5,427,643
`DATED
`June 27, 1995
`INVENTOR(S) : Aitken et all
`
`It is certified that error appears in the above-indentified patent and that said Letters Patent is hereby
`corrected as shown below:
`On the title page, item (54), and column 1:
`The title should be:
`--Method of Using an Adhesive Tape for
`Overcoating Splices in Polymer Coated
`Metal Tapes--.
`
`Signed and Sealed this
`Twelfth Day of September, 1995
`(a teen
`
`BRUCELEBMAN
`Commissioner of Patents and Trademarks
`
`Attest:
`
`Attesting Officer
`
`
`
`