Insulation composition
The present invention relates to a precursor material for an insulation composition, comprising: a crosslinkable graft polymer comprising a polyolefin component and a polyene component; and an antioxidant. The present invention also relates to an insulation composition obtained from the precursor material.
1. A precursor material for an insulation composition, comprising:
a crosslinkable graft polymer comprising a polyolefin component that forms a backbone and a polyene component that forms one or more side chains grafted onto the backbone,
wherein the polyene component is derived from a polyene comprising farnesene; squalene; 1,2,4-trivinylcyclohexane; cyclooctatriene; trans,trans,cis-1,5,9-cyclododecatriene; triallyl isocyanurate (1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione); triallyl cyanurate (2,4,6-triallyloxy-1,3,5-triazine); or a mixture thereof; and
an antioxidant.
2. The precursor material according to claim 1 , wherein the polyolefin component is derived from a polyolefin comprising polyethylene and/or polypropylene.
3. The precursor material according to claim 1 , wherein the polyene component is derived from
1,2,4-trivinylcyclohexane.
4. The precursor material according to claim 1 , wherein the antioxidant:
a. comprises one or more components selected from the group consisting of: phenolic antioxidants, phosphite antioxidants, sulphur-containing antioxidants, aminic antioxidants, and mixtures thereof;
b. comprises a single antioxidant; or
c. comprises a blend of two or more antioxidants.
5. The precursor material according to claim 4 , wherein the single antioxidant has both phenolic functionality and sulphur functionality.
6. The precursor material according to claim 4 , wherein the single antioxidant is 4,4′-thiobis (2-t-butyl-5-methylphenol) or 4,6-bis(octylthiomethyl)-o-cresol.
7. The precursor material according to claim 4 , wherein the blend of two or more antioxidants comprises:
i. at least one fully hindered phenolic antioxidant; at least one partially hindered phenolic antioxidant; and at least one sulphur-containing antioxidant; or
ii. at least one low hindered phenolic antioxidant and/or at least one non-hindered phenolic antioxidant.
8. The precursor material according to claim 1 , further comprising a crosslinking agent.
9. The precursor material according to claim 8 , wherein the crosslinking agent is a peroxide.
10. The precursor material according to claim 9 , wherein the peroxide is selected from the group consisting of dicumylperoxide; 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; tert-butylcumylperoxide; di-tert-amylperoxide; 2,5-di(tert-butylperoxy)-2,5-dimethyl-3-hexyne; di(tert-butyl)peroxide; di(tert-butylperoxy-isopropyl)benzene; butyl-4,4-bis(tert-butylperoxy)valerate; 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; tert-butylperoxybenzoate; dibenzoyl peroxide; and combinations thereof.
11. The precursor material according to claim 1 , further comprising a scorch retarder.
12. The precursor material according to claim 11 , wherein the scorch retarder is 2,4-diphenyl-4-methyl-1-pentene.
13. The precursor material according to claim 1 , wherein the polyene component is derived from a triene.
14. The precursor material according to claim 1 , wherein the polyene component is derived from 1,2,4-trivinylcyclohexane and is present in an amount of from 0.1% to 2% by weight of the polyolefin component, wherein the antioxidant is present in an amount of 0.1% to 0.5% by weight of the polyolefin component, and wherein the precursor material further comprises a scorch retarder in an amount of 0.1% to 1% by weight of the polyolefin component.
15. An insulation composition comprising a crosslinked precursor material according to claim 1 .
16. A wire or cable comprising an electrically conductive material surrounded by the insulation composition according to claim 15 .
17. A process for forming an insulation composition, comprising:
combining a polyolefin, a polyene comprising farnesene; squalene; 1,2,4-trivinylcyclohexane; cyclooctatriene; trans,trans,cis-1,5,9-cyclododecatriene; triallyl isocyanurate (1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione); triallyl cyanurate (2,4,6-triallyloxy-1,3,5-triazine); or a mixture thereof, a crosslinking agent, and an antioxidant to form a reaction mixture; and
heating the reaction mixture to form an insulation composition according to claim 15 .
18. A process for forming a precursor material, comprising:
combining a polyolefin, a polyene comprising farnesene; squalene; 1,2,4-trivinylcyclohexane; cyclooctatriene; trans,trans,cis-1,5,9-cyclododecatriene; triallyl isocyanurate (1,3,5-triallyl-1,3,5-triazinane-2,4,6-trione); triallyl cyanurate (2,4,6-triallyloxy-1,3,5-triazine); or a mixture thereof, and an antioxidant to form a reaction mixture; and
heating the reaction mixture to form a precursor material according to claim 1 .
19. A precursor material for an insulation composition, comprising:
a crosslinkable graft polymer comprising a polyolefin component that forms a backbone and a polyene component that forms one or more side chains grafted onto the backbone, wherein the polyene component is derived from 1,2,4-trivinylcyclohexane;
an antioxidant; and
a scorch retarder.
20. The precursor material according to claim 19 , wherein the scorch retarder comprises 2,4-diphenyl-4-methyl-1-pentene.