CA2421440A1 - Flame retardant dual insulation design and cable construction for plenum applications - Google Patents
Flame retardant dual insulation design and cable construction for plenum applications Download PDFInfo
- Publication number
- CA2421440A1 CA2421440A1 CA 2421440 CA2421440A CA2421440A1 CA 2421440 A1 CA2421440 A1 CA 2421440A1 CA 2421440 CA2421440 CA 2421440 CA 2421440 A CA2421440 A CA 2421440A CA 2421440 A1 CA2421440 A1 CA 2421440A1
- Authority
- CA
- Canada
- Prior art keywords
- flame retardant
- particles
- insulation design
- layer
- dual insulation
- 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.)
- Abandoned
Links
Classifications
-
- 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
- H01B3/44—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 vinyl resins; acrylic resins
- H01B3/443—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 vinyl resins; acrylic resins from vinylhalogenides or other halogenoethylenic compounds
- H01B3/445—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 vinyl resins; acrylic resins from vinylhalogenides or other halogenoethylenic compounds from vinylfluorides or other fluoroethylenic compounds
-
- 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
- H01B3/44—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 vinyl resins; acrylic resins
- H01B3/441—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 vinyl resins; acrylic resins from alkenes
-
- 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
Abstract
A flame and smoke retardant dual insulation design for insulated conductors in a telecommunication cable is disclosed. The insulation comprises an elongate substantially cylindrical fluoro-polymer outer layer and an under layer interposed between the conductor and the outer layer. The under layer includes a metallocene type polyolefin having PTFE micro-particles, a halogen type flame retardant package and clay based nanocomposite type particles, or any combination thereof. This insulation design has the advantage of reducing the thickness of the fluoro-polymer layer.
Description
TITLE OF THE INVENTION
FLAME RETARDANT DUAL INSULATION DESIGN AND CABLE
CONSTRUCTION FOR PLENUM APPLICATIONS
FIELD OF THE INVENTION
The present invention relates to a flame retardant insulation design for electrical cabling. In particular, the present invention relates to a flame and smoke retardant insulation design for telecommunications cables having at least one insulated conductor and a covering jacket where the insulation design is comprised of a layer of fluoro-polymer covering an under layer having a polymer formulation that includes organically modified clay nanocomposite particles-BACKGROUND
In plenum applications, where electrical cabling is run in the spaces created by suspended ceilings or false floors which are also used for the movement of environmental air, building codes and fire regulations typically place very strict requirements in terms of a cable's resistance to open flame and emission of non-toxic fumes and smoke at high temperatures. Typically, in order to meet these requirements, the cabling is enclosed in suitable ducting or, alternatively, cables fabricated using special jackets and other. non-toxic and fire retardant materials are used.
The prior art shows an increasing use of nanocomposites comprising organically modified nanoclays and polyolefin copolymers in the fabrication of materials having flame retardant and smoke retardant properties. For example, in US Patent No. 6,414,070 organically modified nanoclays are used exclusively with polyolefin copolymers to significantly improve the flame retardant properties of the resulting polymeric nanocomposites. In a previous disclosure (US Pat. 5,773,502) it was shown that adding organically modified nanoclays and a polytetrafluoroethylene (PTFE) additive to a polyester material in conjunction with a bromine based organic flame retardant package (with antimony oxide) improved the overall performance of the compound in terms of flame retardation. Thus, the improved formulation has maintained the same flame retardant properties as the original formulation despite a reduction in the initial bromine flame retardant package from 31 % to 18%. One drawback, however, is that bromine based organic flame retardant packages typically generate high smoke levels.
In a more recent disclosure (US Patent No. 6,492,453) it was shown that the addition of organically modified nanoclays to polyolefin copolymers, in conjunction with a non-halogen package containing mainly magnesium hydroxide, resulted in both highly flame retardant and highly smoke retardant formulations. Such polymer formulations, as taught in US Patent No.
6,492,453, were used as insulating dielectrics in cable constructions that have met NFPA 262 and UL 910 test requirements. However, these types of materials contain between 60% and 40% of magnesium hydroxide and, consequently, are difficult to process and typically have very low tensile strength when compared with materials containing a bromine based organic flame retardant package. In a previous disclosure (US Patent No. 5,563,377), Arpin and the undersigned have shown that a cable construction with a Dual Insulation Design (DID) comprised of a top Fluorinated Ethylene Propylene (FEP) layer (for example TefIonT"") and a flame retardant polyolefin under-layer that may contain a bromine based organic flame retardant package, should also meet the NFPA 262 and UL 910 test requirements.
Recent NFPA 262 and UL 910 tests have shown that the substitution of the bromine based organic flame retardant package with a chlorine based organic flame retardant package results in dual insulation cable constructions with considerably improved properties in terms of flame retardant and smoke emissions. However, these constructions have not substantially reduced the amount of FEP required and therefore lead to a smoke and flame retardant jacket that is more expensive then standard plenum jackets.
SUMMARY OF THE INVENTION
The present invention addresses the above and other drawbacks by providing a flame and smoke retardant dual insulation design for conductors, in particular in a telecommunication cable. The dual insulation comprises an elongate substantially cylindrical fluoro-polymer outer layer and an under layer interposed between the conductor and the outer layer. The under layer includes a metallocene type polyolefin having PTFE micro-particles, a halogen type flame retardant package, and clay based nanocomposite particles, or any combination thereof.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
In the present disclosure, we claim that the addition of organically modified nanoclays and a PTFE additive to a polyolefin with a chlorine based organic flame retardant package improves the UL 910 test performance of DID cable constructions. These improvements can result in either a further reduction in the thickness of the FEP layer or in the substitution of the high cost low smoke PVC jacket for a lower cost low smoke PVC jacket, or both.
In an illustrative embodiment, 3% to 8% of organically modified nanoclays and 0.5% to 40% PTFE micro-particles are added to the original chlorine based organic flame retardant package in the form of a masterbatch comprising the above additives dispersed in a matrix of a metallocene type flexomer or elastomer polyolefin. Alternatively, the amount of the chlorine based organic flame retardant additives could be reduced by dilution with the metallocene or polyolefin while adding the same amounts of 3% to 8% of organically modified nanoclays and 0.5% to 40% PTFE micro-particles.
A reduction in the chlorine based organic flame retardant additives results in a corresponding reduction in the smoke emission during the UL 910 test. The addition of the 3% to 8% of organically modified nanoclays and 0.5% to 40%
PTFE micro-particles compensates for the reduction in the chlorine based organic flame retardant additives thereby providing the overall cable with equivalent flame retardant characteristics and improved performance in terms of smoke emissions.
We also claim that the performance of a bromine type flame retardant package is also improved upon the addition of PTFE micro-particles and/or organically modified nanoclays.
Recent UL 910 tests have also shown that a dual insulation construction comprising:
~ a 0.201 inch solid copper conductor;
~ a 2.5 mils under-layer metallocene type polyolefin elastomer containing about 40% PTFE micro-particles;
~ a 5 mils FEP top transparent layer; and ~ a standard Low Smoke PVC jacket (SC III 8511) does not meet current test requirements.
However, when the under-layer was substituted with a 20% foamed composition comprising 50% of the same metallocene type polyolefin elastomer with 40% PTFE micro-particles and 50% of a polyolefin containing a bromine type flame retardant package, the UL 910 test requirements were met.
FLAME RETARDANT DUAL INSULATION DESIGN AND CABLE
CONSTRUCTION FOR PLENUM APPLICATIONS
FIELD OF THE INVENTION
The present invention relates to a flame retardant insulation design for electrical cabling. In particular, the present invention relates to a flame and smoke retardant insulation design for telecommunications cables having at least one insulated conductor and a covering jacket where the insulation design is comprised of a layer of fluoro-polymer covering an under layer having a polymer formulation that includes organically modified clay nanocomposite particles-BACKGROUND
In plenum applications, where electrical cabling is run in the spaces created by suspended ceilings or false floors which are also used for the movement of environmental air, building codes and fire regulations typically place very strict requirements in terms of a cable's resistance to open flame and emission of non-toxic fumes and smoke at high temperatures. Typically, in order to meet these requirements, the cabling is enclosed in suitable ducting or, alternatively, cables fabricated using special jackets and other. non-toxic and fire retardant materials are used.
The prior art shows an increasing use of nanocomposites comprising organically modified nanoclays and polyolefin copolymers in the fabrication of materials having flame retardant and smoke retardant properties. For example, in US Patent No. 6,414,070 organically modified nanoclays are used exclusively with polyolefin copolymers to significantly improve the flame retardant properties of the resulting polymeric nanocomposites. In a previous disclosure (US Pat. 5,773,502) it was shown that adding organically modified nanoclays and a polytetrafluoroethylene (PTFE) additive to a polyester material in conjunction with a bromine based organic flame retardant package (with antimony oxide) improved the overall performance of the compound in terms of flame retardation. Thus, the improved formulation has maintained the same flame retardant properties as the original formulation despite a reduction in the initial bromine flame retardant package from 31 % to 18%. One drawback, however, is that bromine based organic flame retardant packages typically generate high smoke levels.
In a more recent disclosure (US Patent No. 6,492,453) it was shown that the addition of organically modified nanoclays to polyolefin copolymers, in conjunction with a non-halogen package containing mainly magnesium hydroxide, resulted in both highly flame retardant and highly smoke retardant formulations. Such polymer formulations, as taught in US Patent No.
6,492,453, were used as insulating dielectrics in cable constructions that have met NFPA 262 and UL 910 test requirements. However, these types of materials contain between 60% and 40% of magnesium hydroxide and, consequently, are difficult to process and typically have very low tensile strength when compared with materials containing a bromine based organic flame retardant package. In a previous disclosure (US Patent No. 5,563,377), Arpin and the undersigned have shown that a cable construction with a Dual Insulation Design (DID) comprised of a top Fluorinated Ethylene Propylene (FEP) layer (for example TefIonT"") and a flame retardant polyolefin under-layer that may contain a bromine based organic flame retardant package, should also meet the NFPA 262 and UL 910 test requirements.
Recent NFPA 262 and UL 910 tests have shown that the substitution of the bromine based organic flame retardant package with a chlorine based organic flame retardant package results in dual insulation cable constructions with considerably improved properties in terms of flame retardant and smoke emissions. However, these constructions have not substantially reduced the amount of FEP required and therefore lead to a smoke and flame retardant jacket that is more expensive then standard plenum jackets.
SUMMARY OF THE INVENTION
The present invention addresses the above and other drawbacks by providing a flame and smoke retardant dual insulation design for conductors, in particular in a telecommunication cable. The dual insulation comprises an elongate substantially cylindrical fluoro-polymer outer layer and an under layer interposed between the conductor and the outer layer. The under layer includes a metallocene type polyolefin having PTFE micro-particles, a halogen type flame retardant package, and clay based nanocomposite particles, or any combination thereof.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
In the present disclosure, we claim that the addition of organically modified nanoclays and a PTFE additive to a polyolefin with a chlorine based organic flame retardant package improves the UL 910 test performance of DID cable constructions. These improvements can result in either a further reduction in the thickness of the FEP layer or in the substitution of the high cost low smoke PVC jacket for a lower cost low smoke PVC jacket, or both.
In an illustrative embodiment, 3% to 8% of organically modified nanoclays and 0.5% to 40% PTFE micro-particles are added to the original chlorine based organic flame retardant package in the form of a masterbatch comprising the above additives dispersed in a matrix of a metallocene type flexomer or elastomer polyolefin. Alternatively, the amount of the chlorine based organic flame retardant additives could be reduced by dilution with the metallocene or polyolefin while adding the same amounts of 3% to 8% of organically modified nanoclays and 0.5% to 40% PTFE micro-particles.
A reduction in the chlorine based organic flame retardant additives results in a corresponding reduction in the smoke emission during the UL 910 test. The addition of the 3% to 8% of organically modified nanoclays and 0.5% to 40%
PTFE micro-particles compensates for the reduction in the chlorine based organic flame retardant additives thereby providing the overall cable with equivalent flame retardant characteristics and improved performance in terms of smoke emissions.
We also claim that the performance of a bromine type flame retardant package is also improved upon the addition of PTFE micro-particles and/or organically modified nanoclays.
Recent UL 910 tests have also shown that a dual insulation construction comprising:
~ a 0.201 inch solid copper conductor;
~ a 2.5 mils under-layer metallocene type polyolefin elastomer containing about 40% PTFE micro-particles;
~ a 5 mils FEP top transparent layer; and ~ a standard Low Smoke PVC jacket (SC III 8511) does not meet current test requirements.
However, when the under-layer was substituted with a 20% foamed composition comprising 50% of the same metallocene type polyolefin elastomer with 40% PTFE micro-particles and 50% of a polyolefin containing a bromine type flame retardant package, the UL 910 test requirements were met.
5 We, therefore, claim that the addition of organically modified nanoclays to the latter polymer formulation of the under-layer will bring about further reductions in the FEP layer and still result in a dual insulation cable construction that will meet the UL 910 test requirements with good margins.
Although the present invention has been described hereinabove by way of an illustrative embodiment thereof, this embodiment can be modified at will without departing from the spirit and nature of the subject invention.
Although the present invention has been described hereinabove by way of an illustrative embodiment thereof, this embodiment can be modified at will without departing from the spirit and nature of the subject invention.
Claims
1. A flame and smoke retardant dual insulation for an electrical cable having at least one insulated conductor, comprising.
an elongate substantially cylindrical outer layer; and an under layer interposed between the conductor and said jacket;
wherein said under layer includes:
a metallocene type polyolefin having PTFE micro-particles;
a halogen type flame retardant package; and clay based nanocomposite type particles;
or any combination thereof.
an elongate substantially cylindrical outer layer; and an under layer interposed between the conductor and said jacket;
wherein said under layer includes:
a metallocene type polyolefin having PTFE micro-particles;
a halogen type flame retardant package; and clay based nanocomposite type particles;
or any combination thereof.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2421440 CA2421440A1 (en) | 2003-03-10 | 2003-03-10 | Flame retardant dual insulation design and cable construction for plenum applications |
| CA2460451A CA2460451C (en) | 2003-03-10 | 2004-03-10 | Communications cable |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2421440 CA2421440A1 (en) | 2003-03-10 | 2003-03-10 | Flame retardant dual insulation design and cable construction for plenum applications |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2421440A1 true CA2421440A1 (en) | 2004-09-10 |
Family
ID=32932239
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2421440 Abandoned CA2421440A1 (en) | 2003-03-10 | 2003-03-10 | Flame retardant dual insulation design and cable construction for plenum applications |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2421440A1 (en) |
-
2003
- 2003-03-10 CA CA 2421440 patent/CA2421440A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |