Non-halogenated insulation with high oxygen index
AssigneeChamplain Cable Corporation
InventorHoward F. McRae
Life of this patent
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Abstract
The invention features in synergistic combination a new chemistry for fabricating wire and cable insulation and heat-shrinkable tubing and an irradiation process for providing the insulation with both increased tensile strength and increased elongation. The chemistry utilizes a polycondensation-type process wherein a hydrophobic olefinic terpolymer base material having 3% or less carboxyl groups and a hydrophilic flame retardant filler material containing hydroxyl groups is linked to a silicone material containing silanol groups. The insulation is further characterized by an oxygen index in excess of 50.0, resulting from high loadings of the fire retardant filler material, generally in excess of 200 parts by weight of the total material weight.
Claims36
A fire retardant, non-halogenated wire and cable insulation, featuring increased tensile strength and elongation resulting from irradiation of a composition including:
- a) an ethylene vinyl acetate base resin comprising approximately 100 parts by weight of the total composition, and containing carboxyl groups below approximately 3% by weight of said base resin;
- b) a silicone material containing silanol groups and comprising approximately between 15 to 30 parts by weight of the total composition;
- and
- c) a flame retardant hydrated filler material containing hydroxyl groups and comprising greater than 200 parts by weight of the total composition, said silanol groups linking both with the carboxylic groups of the ethylene vinyl acetate base resin, and the hydroxyl groups of the flame retardant hydrated filler material, said silanol groups having sufficient linkage with said carboxyl groups and said hydroxyl groups to provide said composition with a high, flame retardant, oxygen index, but having insufficient linkage capability to allow for extrusion of said composition into wire and cable insulation.
A fire retardant, non-halogenated wire and cable insulation, comprising an irradiated composition whose tensile strength and elongation have both increased as a result of said irradiation, said composition including:
- a) an olefinic terpolymer base material comprising approximately 100 parts by weight of the total composition, and containing carboxyl groups below approximately 3% by weight of said base material;
- b) a silicone material containing silanol groups and comprising approximately between 15 to 30 parts by weight of the total composition;
- and
- c) a flame retardant hydrated filler material containing hydroxyl groups and comprising greater than 200 parts by weight of the total composition, said silanol groups linking both with the carboxylic groups of the olefinic terpolymer base material, and the hydroxyl groups of the flame retardant hydrated filler material via a polycondensation process, said silanol groups having sufficient linkage with said carboxyl groups and said hydroxyl groups to provide said composition with a high, flame retardant, oxygen index, but having insufficient linkage capability to allow for extrusion of said composition into wire and cable insulation.
A fire retardant, non-halogenated wire and cable insulation formed by a polycondensation process comprising, an irradiated composition whose tensile strength and elongation have both increased as a result of said irradiation, said composition including:
- a) a hydrophobic olefinic terpolymer base material containing carboxyl groups below approximately 3% by weight of said base material;
- b) a hydrophilic flame retardant hydrated filler material containing hydroxyl groups and comprising greater than 200 parts by weight of the total composition;
- and
- c) a silicone material containing silanol groups, said silanol groups linking both with the carboxylic groups of the hydrophobic olefinic tarpolymer base material, and the hydroxyl groups of the hydrophilic flame retardant hydrated filler material via said polycondensation process, said silanol groups having sufficient linkage with said carboxyl groups and said hydroxyl groups to provide said composition with a high, flame retardant, oxygen index, but having insufficient linkage capability to allow for extrusion of said composition into wire and cable insulation.
A method of fabricating insulation, comprising the steps of:
- a) linking carboxyl groups contained in a hydrophobic olefinic terpolymer base material with silanol groups contained in a silicone material;
- b) linking silanol groups of said silicone material additionally with hydroxyl groups contained in a hydrophilic fire retardant material, whereby said silicone material is linked to both said hydrophobic and hydrophilic materials;
- and
- c) irradiating the linked hydrophobic and hydrophilic materials to increase both tensile strength and elongation.
[35. A non-halogenated flame retardant insulation having an oxygen index in the approximate range of between 40 and 72.]
[36. The non-halogenated flame retardant insulation of claim 35, wherein said oxygen index is greater than approximately 50.]
Dependencies are inferred from the claim text.