Stabilized moisture-curable polymeric compositions
Silane-crosslinkable polymeric compositions comprising a polyolefin having hydrolyzable silane groups, an acidic silanol condensation catalyst, and a phenolic antioxidant. The phenolic antioxidant has a phenol-based moiety fused with a cyclic ether where the oxygen atom of the cyclic ether is located in the para position relative to the hydroxyl group of the phenol-based moiety. Such crosslinkable polymeric compositions can be employed in various articles of manufacture, such as in the wire and cable industry.
1. A silane-crosslinkable polymeric composition, comprising:
a polyolefin having hydrolyzable silane groups;
an acidic silanol condensation catalyst; and
a phenolic antioxidant having a phenol-based moiety fused with a cyclic ether,
wherein the oxygen atom of said cyclic ether is located in the para position relative to the hydroxyl group of said phenol-based moiety; and
further comprising an ester-functionalized thioether and octyl triethoxy silane, wherein the octyl triethoxy silane is present in from 0.10 to 2 weight percent, based on the entire weight of the silane-crosslinkable polymeric composition.
2. The silane-crosslinkable polymeric composition of claim 1 , wherein said phenolic antioxidant has the following structure:
wherein R 1 , R 2 , R 3 , R 4 , and R 5 are individually hydrogen or a hydrocarbyl moiety, optionally containing one or more heteroatoms.
3. The silane-crosslinkable polymeric composition of claim 2 , wherein each of R 1 , R 2 , R 3 , and R 4 are individually hydrogen or an aliphatic moiety having from 1 to 8 carbon atoms, wherein R 5 is an aliphatic moiety having from 10 to 20 carbon atoms.
4. The silane-crosslinkable polymeric composition of claim 2 , wherein each of R 1 , R 2 , R 3 , and R 4 is individually hydrogen or a C 1 to C 4 straight-chain alkyl group, wherein R 5 is a C 14 to C 18 saturated or unsaturated aliphatic chain having one or more branches.
5. The silane-crosslinkable polymeric composition of claim 1 , wherein said ester-functionalized thioether has the following structure:
wherein R 3 is an alkylene radical having from 1 to 10 carbon atoms, R 4 and R 5 are individually any aliphatic or aromatic radical, optionally containing one or more heteroatoms.
6. The silane-crosslinkable polymeric composition of claim 1 , wherein said ester-functionalized thioether has a structure selected from the following structures (I)-(III):
wherein R 6 is an alkyl radical having from 4 to 20 carbon atoms.
7. The silane-crosslinkable polymeric composition of claim 1 , wherein said ester-functionalized thioether is selected from the group consisting of distearyl thiodipropionate, dilauryl thiodipropionate, pentaerythritol tetrakis(β-laurylthiopropionate), thiobis-[2-tert-butyl-5-methyl-4,1-phenylene] bis [3-(dodecylthio)propionate], and combinations of two or more thereof.
8. The silane-crosslinkable polymeric composition of claim 1 , wherein said polyolefin having hydrolyzable silane groups is selected from the group consisting of (i) an interpolymer of ethylene and a hydrolyzable silane, (ii) an interpolymer of ethylene, one or more C 3 or higher α-olefins and/or unsaturated esters, and a hydrolyzable silane, (iii) a homopolymer of ethylene having a hydrolyzable silane grafted to its backbone, and (iv) an interpolymer of ethylene and one or more C 3 or higher α-olefins and/or unsaturated esters, such interpolymer having a hydrolyzable silane grafted to its backbone.
9. A coated conductor, comprising:
(a) conductor comprising one or more wire(s) or optical fiber(s); and
(b) a crosslinked polymeric composition prepared from the silane-crosslinkable polymeric composition of claim 1 ,
wherein said crosslinked polymeric composition surrounds at least a portion of said conductor.