GB2233580A - Wire insulation - Google Patents

Wire insulation Download PDF

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Publication number
GB2233580A
GB2233580A GB8927831A GB8927831A GB2233580A GB 2233580 A GB2233580 A GB 2233580A GB 8927831 A GB8927831 A GB 8927831A GB 8927831 A GB8927831 A GB 8927831A GB 2233580 A GB2233580 A GB 2233580A
Authority
GB
United Kingdom
Prior art keywords
wire according
siloxane
halogen
coating
poly
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.)
Granted
Application number
GB8927831A
Other versions
GB2233580B (en
GB8927831D0 (en
Inventor
Richard John Murphy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
VACTITE Ltd
Original Assignee
VACTITE Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from GB898915349A external-priority patent/GB8915349D0/en
Priority claimed from GB898917904A external-priority patent/GB8917904D0/en
Application filed by VACTITE Ltd filed Critical VACTITE Ltd
Publication of GB8927831D0 publication Critical patent/GB8927831D0/en
Priority to EP90306756A priority Critical patent/EP0407061A1/en
Priority to BR909003180A priority patent/BR9003180A/en
Priority to JP17547590A priority patent/JPH0355713A/en
Publication of GB2233580A publication Critical patent/GB2233580A/en
Application granted granted Critical
Publication of GB2233580B publication Critical patent/GB2233580B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/28—Protection against damage caused by moisture, corrosion, chemical attack or weather
    • H01B7/2813—Protection against damage caused by electrical, chemical or water tree deterioration

Abstract

A wire having an inner coating of a highly-insulative, halogen-free plastics material and a halogen-free, hard, flexible outer coating of a copolymer of, or a mixture of, a siloxane and a polyetherimide. An improvement is possible by adding a layer of poly-ether-etherketone as a further outer coating over the flexible coating.

Description

Wire Insulation This invention relates to plastics insulated wires.
It has been found extremely difficult, if not impossible, to produce a wire insulation which contains no halogens, passes high temperature flammability tests, has a high mechanical strength, is sufficiently flexible to be viable as a wire insulation, and does not catastrophically allow arc tracking.
It is well known that highly aromatic polymers are relatively non-flammable and have, in general, a high mechanical strength. However, these materials are stiff, and render the wire insulation rigid, so that the coated wire becomes non-flexible and effectively non-usable in practice. They are usually susceptible to arc tracking because they have a highly aromatic nature.
Accordingly, the invention provides a wire having an inner coating of a highly-insulative, halogen-free plastics material and a halogen-free, hard, flexible outer coating of a copolymer of, or a mixture of, a siloxane and a polyetherimide.
The inner coating may be of any modified polyolefinic material which is halogen-free and which does not promote arc-tracking. It may be cross-linked by radiation but this is not necessary if a high temperature deformation resistance is inherent in the polymer, or is provided by some other means. Suitable materials, singly or in combination, are: poly(ethylene vinyl acetate)-EVA or VAE; poly(ethylene); poly(butyleneteraphthalate)-PBT; a thermoplastic elastomer; and a cross-linked elastomer.
The outer coating is of low flammability and is preferably cross-linkable. The siloxane may be polydimethylsiloxane or another substituted siloxane, and a suitable copolymer of polydimethylsiloxane and polyetherimide is available from General Electric Plastics Company (of the U.S.A.) under the trademark "SILTEM". In addition, it is found that improved performance can be obtained by blending the "SILTEM" copolymer with such polymers as polyphenylene ether or nylon.
The insulation may be improved significantly by the addition of a layer of poly-ether-etherketone ("PEEK") over the two coatings mentioned above. The flammability is lowered, the resistance to cut-through and abrasion is raised, and the resistance to attack by fluid or gaseous chemicals is improved. It is found surprisingly that this additional layer of PEEK does not significantly reduce the flexibility or resistance to arc tracking afforded by the first two coatings.
EXAMPLE An electric wire was made by coating a conductor with an extruded inner layer of modified polyethylene and then an extruded outer layer of "SILTEM" copolymer. The coated wire was then subjected to electron beam irradiation for cross-linking to a dose of 8 Mrad. in one case, and to 10, 12 and 15 Mrad. in other cases.
All wires satisfied tests for vertical flammability, scrape abrasion, flexibility, arc tracking, cut-through resistance and resistance to oils and water.

Claims (8)

1. A wire having an inner coating of a highly-insulative, halogen-free plastics material and a halogen-free, hard, flexible outer coating comprising a copolymer of, or a mixture of, a siloxane and a polyetherimide.
2. A wire according to Claim 1, in which the inner coating is of any modified polyolefinic material which is halogen-free and which does not promote arc-tracking.
3. A wire according to Claim 2, in which the inner coating is of one or more materials selected from: poly(ethylene vinyl acetate)-EVA or VAE; poly(ethylene); poly(butyleneteraphthalate)-PBT; a thermoplastic elastomer; and a cross-linked elastomer.
4. A wire according to Claim 1, 2 or 3, in which the siloxane is polydimethylsiloxane or another substituted siloxane.
5. A wire according to any preceding claim, in which the outer coating is comprised of a mixture of a copolymer of siloxane and polyetherimide and another polymer.
6. A wire according to Claim 5, in which the said other polymer is polyphenylene oxide.
7. A wire according to Claim 5, in which the said other polymer is nylon.
8. A wire according to any preceding claim, further comprising an outer layer of PEEK over the flexible outer coating.
GB8927831A 1989-07-04 1989-12-08 Wire insulation Expired - Fee Related GB2233580B (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP90306756A EP0407061A1 (en) 1989-07-04 1990-06-20 Wire insulation
BR909003180A BR9003180A (en) 1989-07-04 1990-07-04 ISOLATED WIRE
JP17547590A JPH0355713A (en) 1989-07-04 1990-07-04 Wire insulator

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB898915349A GB8915349D0 (en) 1989-07-04 1989-07-04 Wire insulation
GB898917904A GB8917904D0 (en) 1989-08-04 1989-08-04 Wire insulation

Publications (3)

Publication Number Publication Date
GB8927831D0 GB8927831D0 (en) 1990-02-14
GB2233580A true GB2233580A (en) 1991-01-16
GB2233580B GB2233580B (en) 1993-01-06

Family

ID=26295574

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8927831A Expired - Fee Related GB2233580B (en) 1989-07-04 1989-12-08 Wire insulation

Country Status (1)

Country Link
GB (1) GB2233580B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29702560U1 (en) * 1997-02-14 1997-07-03 Draka Deutschland Gmbh & Co Kg Ignition cable for motor vehicles

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29702560U1 (en) * 1997-02-14 1997-07-03 Draka Deutschland Gmbh & Co Kg Ignition cable for motor vehicles

Also Published As

Publication number Publication date
GB2233580B (en) 1993-01-06
GB8927831D0 (en) 1990-02-14

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Legal Events

Date Code Title Description
730A Proceeding under section 30 patents act 1977
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19951208