CA1093652A - Electrical conductor with an outer layer of crosslinked insulation - Google Patents
Electrical conductor with an outer layer of crosslinked insulationInfo
- Publication number
- CA1093652A CA1093652A CA307,158A CA307158A CA1093652A CA 1093652 A CA1093652 A CA 1093652A CA 307158 A CA307158 A CA 307158A CA 1093652 A CA1093652 A CA 1093652A
- Authority
- CA
- Canada
- Prior art keywords
- conductor
- outer layer
- pvc
- less
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
- H01B7/29—Protection against damage caused by extremes of temperature or by flame
- H01B7/295—Protection against damage caused by extremes of temperature or by flame using material resistant to flame
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
- H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
- H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/02—Disposition of insulation
- H01B7/0275—Disposition of insulation comprising one or more extruded layers of insulation
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Insulated Conductors (AREA)
- Organic Insulating Materials (AREA)
Abstract
Abstract of the Disclosure An electrical conductor has a conductive core, an intervening layer of insulating material and an outer layer of irradiation cross-linked insulation which is efficient, has acceptable elongation and flexibility, is economic to make and easily strippable. The outer layer is compound composed of PVC, difunctional and trifunctional monomers and a plasticizer, the PVC content being over 50% and less than 79% by weight of the total composition, the mixture of monomers being less than about 30%, by weight.
Description
3~iZ
This invention relates to an electrical conductor having an irradiation crosslinked outer layer of insulating material, with an intervening layer of insulation between the conductor and outer layer.
It has been proposed to use an irradiation crosslinkable medium which is between 10 and 50 phr (parts per hundred) of the total composition. Such medium itself must contain at least 50% difunctional monomer. A further inclusion in the crosslinkable medium has been proposed of at least one cyclic ether to stabilize against development of colour centres, this further inclusion of about 20% of the total medium. Such formulations are disclosed in United States Patent No. 3,623,940 issued November 30, 1971 and Canadian Patent No. 971,694 issued July 22, 1975.
Compounds using existing formulating procedures do not adequately deal with the problem of maintaining acceptable wire elongation and flexibility together with high abrasion and low blocking characteristics.
The present invention provides a conductor having an outer layer of irradiation crosslinkable formulation, over an intervening insulating layer, the outer layer including over 50%
by weight of PVC but less than 79%, less than 30% of a mixture of a difunctional and a trifunctional acrylic monomer and a plasticizer.
Other additives, such as stabilizer, antioxidant and filler can also be included. The invention provides a conductor having an outer insulation layer which is efficient, with acceptable elongation and flexibility, is economic to make and is easily strippable.
The invention will be readily understood by the following description of certain embodiments, by way of example, in conjunction with the accompanying drawing which is a transverse cross-section through an insulated conductor in accordance with 1~93~;5iZ
the present invention.
The invention is generally utilized to provide a conductor having an outer layer of crosslinked insulation, over an intervening layer of any other insulation over which the outer layer can be formed acceptably, such as PVC, and polyolefin and other insulating materials. In the drawing, the conductor core is indicated at 10, the intervening layer of insulation at 11 and the outer layer of crosslinked insulation at 12. The material of the core 10 is not critical, for example copper or aluminum, or alloys of either of these materials. The conductor may be inned.
The intervening layer 11 may be formed as a single layer or as a plurality of layers and may conceivably be of layers of differing materials but forming a general layer of insulation between the -~
; core 10 and the outer layer 12.
The outer layer 12 is a compound comprising PVC, a crosslinking medium which is a blend of difunctional and trifunctional acrylic monomers of about equal proportions, and a plasticizer. Lead salts, for example tetrabasic lead fumarate, can be included as a stabilizer and finely divided calcium carbonate can be included as a filler. A fire retardant material, such as antimony trioxide, can also be included. The outer layer compound is manufactured by conventional processes, for example dry blending, pellet manufacture, extrusion and then irradiation - up to 10 MRad dose level.
Two typical compounds for the outer layer 12 are as follows:-#1 #2 (phr) % (phr) %
PVC 100 60.86 100 52.0 TEGDM 10 6.09 10 5.2 TMPTM 10 6.09 10 5.2 l(~f~3ti~ 2 #1 #2 (phr) % (phr) %
TOTM 20 12.17 20 10.4 DOP 17 10.34 17 8.84 Stabilizer 7 4.26 7 3.64 Calcium Carbonate ~ 25 13.0 h~ Antioxidant .3 ~U~~ .3 .16 Antimony Trioxide - - 3 1.56 where TEGDM = Tetraethylene Glycol Dimethacrylate - a difunctional monomer.
TMPTM = Trimethylolpropane Trimethacrylate - a trifunctional monomer TOTM = Trioctyl Trimaletate - a plasticizer DOP = Dioctyl Phtalate - a plasticizer.
The actual ranges of the various constituents of the compound can vary, but the PVC content is over 50%, by weight, of the total composition but less than 79% and in many cases is less than 65%.
The intermediate layer 11 is applied by conventional means and the material, or materials, of the layer 11 are manufactured by conventional processes.
The invention provides a conductor having a normal core, a conventional insulating layer over the core and a cross-linked outer layer. The crosslinked outer layer is tough and flexible, but with the combination of the underlying intervening layer is easily strippable. A conductor in accordance with the present invention is particularly useful for switchboard wiring in a telecommunications system.
This invention relates to an electrical conductor having an irradiation crosslinked outer layer of insulating material, with an intervening layer of insulation between the conductor and outer layer.
It has been proposed to use an irradiation crosslinkable medium which is between 10 and 50 phr (parts per hundred) of the total composition. Such medium itself must contain at least 50% difunctional monomer. A further inclusion in the crosslinkable medium has been proposed of at least one cyclic ether to stabilize against development of colour centres, this further inclusion of about 20% of the total medium. Such formulations are disclosed in United States Patent No. 3,623,940 issued November 30, 1971 and Canadian Patent No. 971,694 issued July 22, 1975.
Compounds using existing formulating procedures do not adequately deal with the problem of maintaining acceptable wire elongation and flexibility together with high abrasion and low blocking characteristics.
The present invention provides a conductor having an outer layer of irradiation crosslinkable formulation, over an intervening insulating layer, the outer layer including over 50%
by weight of PVC but less than 79%, less than 30% of a mixture of a difunctional and a trifunctional acrylic monomer and a plasticizer.
Other additives, such as stabilizer, antioxidant and filler can also be included. The invention provides a conductor having an outer insulation layer which is efficient, with acceptable elongation and flexibility, is economic to make and is easily strippable.
The invention will be readily understood by the following description of certain embodiments, by way of example, in conjunction with the accompanying drawing which is a transverse cross-section through an insulated conductor in accordance with 1~93~;5iZ
the present invention.
The invention is generally utilized to provide a conductor having an outer layer of crosslinked insulation, over an intervening layer of any other insulation over which the outer layer can be formed acceptably, such as PVC, and polyolefin and other insulating materials. In the drawing, the conductor core is indicated at 10, the intervening layer of insulation at 11 and the outer layer of crosslinked insulation at 12. The material of the core 10 is not critical, for example copper or aluminum, or alloys of either of these materials. The conductor may be inned.
The intervening layer 11 may be formed as a single layer or as a plurality of layers and may conceivably be of layers of differing materials but forming a general layer of insulation between the -~
; core 10 and the outer layer 12.
The outer layer 12 is a compound comprising PVC, a crosslinking medium which is a blend of difunctional and trifunctional acrylic monomers of about equal proportions, and a plasticizer. Lead salts, for example tetrabasic lead fumarate, can be included as a stabilizer and finely divided calcium carbonate can be included as a filler. A fire retardant material, such as antimony trioxide, can also be included. The outer layer compound is manufactured by conventional processes, for example dry blending, pellet manufacture, extrusion and then irradiation - up to 10 MRad dose level.
Two typical compounds for the outer layer 12 are as follows:-#1 #2 (phr) % (phr) %
PVC 100 60.86 100 52.0 TEGDM 10 6.09 10 5.2 TMPTM 10 6.09 10 5.2 l(~f~3ti~ 2 #1 #2 (phr) % (phr) %
TOTM 20 12.17 20 10.4 DOP 17 10.34 17 8.84 Stabilizer 7 4.26 7 3.64 Calcium Carbonate ~ 25 13.0 h~ Antioxidant .3 ~U~~ .3 .16 Antimony Trioxide - - 3 1.56 where TEGDM = Tetraethylene Glycol Dimethacrylate - a difunctional monomer.
TMPTM = Trimethylolpropane Trimethacrylate - a trifunctional monomer TOTM = Trioctyl Trimaletate - a plasticizer DOP = Dioctyl Phtalate - a plasticizer.
The actual ranges of the various constituents of the compound can vary, but the PVC content is over 50%, by weight, of the total composition but less than 79% and in many cases is less than 65%.
The intermediate layer 11 is applied by conventional means and the material, or materials, of the layer 11 are manufactured by conventional processes.
The invention provides a conductor having a normal core, a conventional insulating layer over the core and a cross-linked outer layer. The crosslinked outer layer is tough and flexible, but with the combination of the underlying intervening layer is easily strippable. A conductor in accordance with the present invention is particularly useful for switchboard wiring in a telecommunications system.
Claims (9)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:-
1. An electrical conductor comprising an electrically conducting core, an intervening layer of insulating material and an outer layer of irradiation crosslinked insulation, the outer layer being a compound composed of PVC, a mixture of difunctional and trifunctional acrylic monomers and a plastizer, the PVC content being over 50% and less than 79% by weight, of the total composition and the mixture of monomers being less than about 30% by weight.
2. A conductor as claimed in claim 1, the difunctional and trifunctional monomers of about equal proportions.
3. A conductor as claimed in claim 1, said PVC content being over 50% and less than about 65%.
4. A conductor as claimed in claim 1, said intervening layer being of PVC.
5. A conductor as claimed in claim 1, said intervening layer being a polyolefin.
6. A conductor as claimed in claim 1, said intervening layer composed of a plurality of layers of insulating material.
7. A conductor as claimed in claim 1, said compound including a stabilizer.
8. A conductor as claimed in claim 1, said compound including a fire retardant material.
9. A conductor as claimed in claim 1, said compound including a filler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA307,158A CA1093652A (en) | 1978-07-11 | 1978-07-11 | Electrical conductor with an outer layer of crosslinked insulation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA307,158A CA1093652A (en) | 1978-07-11 | 1978-07-11 | Electrical conductor with an outer layer of crosslinked insulation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1093652A true CA1093652A (en) | 1981-01-13 |
Family
ID=4111877
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA307,158A Expired CA1093652A (en) | 1978-07-11 | 1978-07-11 | Electrical conductor with an outer layer of crosslinked insulation |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1093652A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0120382A1 (en) * | 1983-03-25 | 1984-10-03 | SOCIETA' CAVI PIRELLI S.p.A. | Low-voltage cable |
-
1978
- 1978-07-11 CA CA307,158A patent/CA1093652A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0120382A1 (en) * | 1983-03-25 | 1984-10-03 | SOCIETA' CAVI PIRELLI S.p.A. | Low-voltage cable |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |