Stabilized Cross-Linked Polyolefin Compositions

A composition comprising:

• (a) at least one polyolefin;
• (b) at least one organic peroxide;
• and
• (c) an antioxidant mixture comprising:
• (i) 100 to 5,000 ppm of at least one fast radical scavenger selected from the group consisting of α-tocopherol;
• β-tocopherol;
• γ-tocopherol;
• δ-tocopherol;
• 4,6-bis (octylthiomethyl) o-cresol and derivatives thereof;
• 4,4′-thiobis(2-methyl-6-t-butylphenol), 4,4′-thiobis(2-t-butyl-5-methylphenol);
• 2,2′-thiobis(6-t-butyl-4-methylphenol);
• 2,2′-thiobis 4-octyl phenol;
• 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione;
• 2,5-di-t-amylhydroquinone;
• a polymeric sterically hindered phenol with CAS number 36443-68-2;
• oxidized bis(hydrogenated tallow alkyl) amines;
• bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl)sebacate;
• 4,4′-bis(α,α-dimethylbenzyl) diphenylamine;
• N-phenyl-styrenated benzenamine;
• diphenylamine/acetone reaction product;
• p-(p-toluene-sulfonylamido)-diphenylamine;
• and mixtures thereof;
• and
• (ii) 100 to 8,000 ppm of at least one long term stabilizer selected from the group consisting of 2,2′-thiodiethylene bis[3(3,5-di-t-butyl-4-hydroxyphenyl) propionate];
• tetrakismethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane;
• octadecyl 3-(3′,5′-di-t-butyl-4′-hydroxy-phenyl)propionate;
• C9-C11 linear and branched alkyl esters of 3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionic acid;
• C13-C15 linear and branched alkyl esters of 3-(3′,5′-di-t-butyl-4′-hydroxyphenyl) propionic acid;
• 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate;
• 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene;
• N,N′-hexamethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide];
• 1,2-bis(3,5-di-t-butyl-4-hydroxyhydrocinnamoyl) hydrazine;
• distearyl 3,3′-thiopropionate;
• dilauryl 3,3′-thiopropionate;
• ditridecylthiodipropionate;
• mixed lauryl-+stearylthiopropionate;
• pentaerythritol tetrakis(β-laurylthiopropionate);
• polymerized 1,2-dihydro-2,2,4-trimethylquinoline;
• 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine;
• 4,4′-bis(α,α-dimethylbenzyl) diphenylamine;
• N-phenyl-styrenated benzenamine;
• diphenylamine/acetone reaction product;
• p-(p-toluene-sulfonylamido)-diphenylamine;
• and mixtures thereof.

An article of manufacture comprising insulating material comprising a composition comprising:

• (a) at least one polyolefin;
• (b) at least one organic peroxide;
• and
• (c) an antioxidant mixture of
• (i) at least one fast radical scavenger selected from the group consisting of low hindered phenols, low hindered thiophenols, low hindered thiobisphenols, aliphatic amines, aromatic amines, NOR HALS, hydroxylamines, and mixtures thereof;
• and
• (ii) at least one long term stabilizer selected from the group consisting of low hindered phenols, highly hindered phenols, thiosynergists, aliphatic amines, aromatic amines, HALS, hydroxylamines, and mixtures thereof.

An article of manufacture comprising insulating means comprising a composition comprising:

• (a) at least one polyolefin;
• (b) at least one organic peroxide;
• and
• (c) an antioxidant mixture of
• (i) 100 to 5,000 ppm of at least one fast radical scavenger selected from the group consisting of α-tocopherol;
• β-tocopherol;
• γ-tocopherol;
• δ-tocopherol;
• 4,6-bis (octylthiomethyl) o-cresol and derivatives thereof;
• 4,4′-thiobis(2-methyl-6-t-butylphenol), 4,4′-thiobis(2-t-butyl-5-methylphenol);
• 2,2′-thiobis(6-t-butyl-4-methylphenol);
• 2,2′-thiobis 4-octyl phenol;
• 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione;
• 2,5-di-t-amylhydroquinone;
• a polymeric sterically hindered phenol with CAS number 36443-68-2;
• oxidized bis(hydrogenated tallow alkyl) amines;
• bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl)sebacate;
• 4,4′-bis(α,α-dimethylbenzyl) diphenylamine;
• N-phenyl-styrenated benzenamine;
• diphenylamine/acetone reaction product;
• p-(p-toluene-sulfonylamido)-diphenylamine;
• and mixtures thereof;
• and
• (ii) 100 to 8,000 ppm of at least one long term stabilizer selected from the group consisting of 2,2′-thiodiethylene bis[3(3,5-di-t-butyl-4-hydroxyphenyl) propionate];
• tetrakismethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane;
• octadecyl 3-(3′,5′-di-t-butyl-4′-hydroxy-phenyl)propionate;
• C9-C11 linear and branched alkyl esters of 3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionic acid;
• C13-C15 linear and branched alkyl esters of 3-(3′,5′-di-t-butyl-4′-hydroxyphenyl) propionic acid;
• 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate;
• 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene;
• N,N′-hexamethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide];
• 1,2-bis(3,5-di-t-butyl-4-hydroxyhydrocinnamoyl) hydrazine;
• distearyl 3,3′-thiopropionate;
• dilauryl 3,3′-thiopropionate;
• ditridecylthiodipropionate;
• mixed lauryl-+stearylthiopropionate;
• pentaerythritol tetrakis(β-laurylthiopropionate);
• polymerized 1,2-dihydro-2,2,4-trimethylquinoline;
• 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine;
• 4,4′-bis(α,α-dimethylbenzyl) diphenylamine;
• N-phenyl-styrenated benzenamine;
• diphenylamine/acetone reaction product;
• p-(p-toluene-sulfonylamido)-diphenylamine;
• and mixtures thereof.

A method for stabilizing polyolefins for use as insulating media in medium and high voltage wire and cable comprising adding to said polyolefin:

• at least one organic peroxide;
• and
• an antioxidant mixture of
• at least one fast radical scavenger selected from the group consisting of low hindered phenols, low hindered thiophenols, low hindered thiobisphenols, aliphatic amines, aromatic amines, NOR HALS, hydroxylamines, and mixtures thereof;
• and
• at least one long term stabilizer selected from the group consisting of low hindered phenols, highly hindered phenols, thiosynergists, aliphatic amines, aromatic amines, HALS, hydroxylamines, and mixtures thereof.

A method for stabilizing polyolefins for use as insulating media in medium and high voltage wire and cable comprising adding to said polyolefin:

• at least one organic peroxide;
• and
• an antioxidant mixture of
• 100 to 5,000 ppm of at least one fast radical scavenger selected from the group consisting of α-tocopherol;
• β-tocopherol;
• γ-tocopherol;
• δ-tocopherol;
• 4,6-bis (octylthiomethyl) o-cresol and derivatives thereof;
• 4,4′-thiobis(2-methyl-6-t-butylphenol), 4,4′-thiobis(2-t-butyl-5-methylphenol);
• 2,2′-thiobis(6-t-butyl-4-methylphenol);
• 2,2′-thiobis 4-octyl phenol;
• 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione;
• 2,5-di-t-amylhydroquinone;
• a polymeric sterically hindered phenol with CAS number 36443-68-2;
• oxidized bis(hydrogenated tallow alkyl) amines;
• bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl)sebacate;
• 4,4′-bis(α,α-dimethylbenzyl) diphenylamine;
• N-phenyl-styrenated benzenamine;
• diphenylamine/acetone reaction product;
• p-(p-toluene-sulfonylamido)-diphenylamine;
• and mixtures thereof;
• and
• 100 to 8,000 ppm of at least one long term stabilizer selected from the group consisting of 2,2′-thiodiethylene bis[3(3,5-di-t-butyl-4-hydroxyphenyl) propionate];
• tetrakismethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane;
• octadecyl 3-(3′,5′-di-t-butyl-4′-hydroxy-phenyl)propionate;
• C9-C11 linear and branched alkyl esters of 3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionic acid;
• C13-C15 linear and branched alkyl esters of 3-(3′,5′-di-t-butyl-4′-hydroxyphenyl) propionic acid;
• 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate;
• 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene;
• N,N′-hexamethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide];
• 1,2-bis(3,5-di-t-butyl-4-hydroxyhydrocinnamoyl) hydrazine;
• distearyl 3,3′-thiopropionate;
• dilauryl 3,3′-thiopropionate;
• ditridecylthiodipropionate;
• mixed lauryl-+stearylthiopropionate;
• pentaerythritol tetrakis(β-laurylthiopropionate);
• polymerized 1,2-dihydro-2,2,4-trimethylquinoline;
• 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine;
• 4,4′-bis(α,α-dimethylbenzyl) diphenylamine;
• N-phenyl-styrenated benzenamine;
• diphenylamine/acetone reaction product;
• p-(p-toluene-sulfonylamido)-diphenylamine;
• and mixtures thereof.