Abstract Elastomeric compositions that are halogen-free, flame retardant and resistant to fluids and suitable for sheathing cables to NES 518 comprise (in parts by weight): 40 - 65 parts of an EVA with a vinyl acetate content of at least 70%; 35 - 60 parts of a fully hydrogenated butadiene/acrylonitrile copolymer, making a total polymer content of 100 parts; 4 -10 parts of a plasticiser; 130 - 160 parts of a high-purity grade of alumina trihydrate filler with a BET surface area greater than 6 m²/g; 1 - 3 parts of a coupling agent for the filler; and a chemical curing agent in an amount sufficient to cross-link the polymer constituent but not sufficient to reduce the tear strength of the cured composition below a limit of 5N/mm.
Halogen-free elastomeric composition comprising (in parts by weight): 40 to 65 parts of an EVA with a vinyl acetate content of more than 60%; 35 - 60 parts of a fully hydrogenated butadiene/acrylonitrile copolymer, making a total polymer content of 100 parts; 4 -10 parts of a plasticiser; 130 - 160 parts of a high-purity grade of alumina trihydrate filler with a BET surface area greater than 6 m²/g; 1 - 3 parts of a coupling agent for the filler; and a chemical curing agent in an amount sufficient to cross-link the polymer constituent but not sufficient to reduce the tear strength of the cured composition below a limit of 5N/mm/.
Claim 2
Dependent Claim
111 words
Halogen-free elastomeric composition comprising (in parts by weight): 40 to 65 parts of an EVA with a vinyl acetate content of more than 60%; 35 - 60 parts of a fully hydrogenated butadiene/acrylonitrile copolymer, making a total polymer content of 100 parts; 4 -10 parts of a plasticiser; 130 - 160 parts of a high-purity grade of alumina trihydrate filler with a BET surface area greater than 6 m²/g; 1 - 3 parts of a coupling agent for the filler; and a chemical curing agent in an amount sufficient to cross-link the polymer constituent but not sufficient to reduce the tear strength of the cured composition below a limit of 5N/mm/.
Claim 3
Dependent Claim
27 words
A composition as claimed in Claim 1 in which the filler gives, when tested according to the Appendix herein, a specific conductance of less that 100 µS.
Claim 4
Dependent Claim
23 words
A composition as claimed in Claim 1 or Claim 2 in which the filler has a BET surface area of at least 12m²/g.
Claim 5
Dependent Claim
24 words
A composition as claimed in any one of Claims 1 - 3 comprising two grades of alumina trihydrate of substantially different particle size/surface area.
Claim 6
Dependent Claim
23 words
A composition as claimed in any one of the preceding Claims in which the EVA has a vinyl acetate content of about 70%.
Claim 7
Dependent Claim
22 words
A composition as claimed in any one of the preceding claims in which the amount of EVA present is about 60 parts.
Claim 8
Dependent Claim
19 words
A composition as claimed in any one of the preceding claims in which the coupling agent is a silane.
Claim 9
Dependent Claim
22 words
A composition as claimed in any one of Claims 1 - 7 in which the coupling agent is vinyl tris (methoxyethoxy) silane.
Claim 10
Dependent Claim
28 words
A composition as claimed in any one of the preceding claims in which the curing agent comprises bis ( tert butylperoxy iso propyl) benzene in combination with triallylcyanurate.
Claim 11
Dependent Claim
15 words
An electric cable sheathed with the composition claimed in any one of the preceding Claims.