摘要:
A molded or extruded article, e.g., an electrical part or shielded cable, comprises at least one insulation layer and at least one semiconductive layer, the semiconductive layer thick and comprising in weight percent: A. 1 to 30 wt % of conductive filler; B. 10 to 90 wt % of a non-olefin elastomer; C. 10 to 90 wt % of an olefin elastomer; and D. Optionally, 0.5 to 2.5 wt % of peroxide. Carbon black and/or metal particulates or powder typically comprise the filler, silicone or urethane rubber the non-olefin elastomer, and EPR or EPDM the olefin elastomer.
摘要:
Scorch is inhibited during the free-radical crosslinking of a crosslinkable polymer, e.g., an EPDM, by incorporating into the polymer before melt processing and crosslinking a scorch inhibiting amount of a derivative, preferably an ether, ester or urethane derivative, of a TEMPO compound, e.g., 4-hydroxy-tetrahydrocarbylpiperidin-1-oxyl. The scorch inhibitors of this invention perform as well, if not better, than their 4-hydroxy-tetrahydrocarbylpiperidin-1-oxyl counterparts in similar polymer compositions and under similar conditions in terms of scorch inhibition and ultimate degree of crosslinking, but exhibit less volatility and less migration within the polymer composition.
摘要:
Scorch is inhibited during the free-radical crosslinking of a crosslinkable polymer, e.g., an EPDM, by incorporating into the polymer before melt processing and crosslinking a scorch inhibiting amount of a derivative, preferably an ether, ester or urethane derivative, of a TEMPO compound, e.g., 4-hydroxy-tetrahydrocarbylpiperidin-1-oxyl. The scorch inhibitors of this invention perform as well, if not better, than their 4-hydroxy-tetrahydrocarbylpiperidin-1-oxyl counterparts in similar polymer compositions and under similar conditions in terms of scorch inhibition and ultimate degree of crosslinking, but exhibit less volatility and less migration within the polymer composition.
摘要:
A process for manufacturing a multilayer article, the article comprising two crosslinked semiconductive layers separated by and bonded to an insulation layer, the semiconductive layers formed from a peroxide-crosslinkable olefin elastomer and the insulation layer comprising composition comprising a silane-grafted olefinic elastomer, the process comprises the steps of: (A) injecting the silane-grafted olefinic elastomer between the two crosslinked semiconductive layers so as to have direct contact with each semiconductive layer, and (B) crosslinking the silane-grafted olefinic elastomer in the absence of a peroxide catalyst.
摘要:
A process for manufacturing a multilayer article, the article comprising two crosslinked semiconductive layers separated by and bonded to an insulation layer, the semiconductive layers formed from a peroxide-crosslinkable olefin elastomer and the insulation layer comprising composition comprising a silane-grafted olefinic elastomer, the process comprises the steps of: (A) injecting the silane-grafted olefinic elastomer between the two crosslinked semiconductive layers so as to have direct contact with each semiconductive layer, and (B) crosslinking the silane-grafted olefinic elastomer in the absence of a peroxide catalyst.
摘要:
Crosslinked, melt-shaped articles are manufactured by a process that does not require the use of post-shaping external heat or moisture, the process comprising the steps of: A. Forming a crosslinkable mixture of a 1. Organopolysiloxane containing one or more functional end groups; and 2. Silane-grafted or silane-copolymerized polyolefin; and B. Melt-shaping and partially crosslinking the mixture; and C. Cooling and continuing crosslinking the melt-shaped article. Crosslinking is promoted by the addition of a catalyst to the mixture before or during melt-shaping or to the melt-shaped article.
摘要:
Scorch is inhibited during the free-radical crosslinking of a crosslinkable polymer, e.g., an EPDM, by incorporating into the polymer before melt processing and crosslinking a scorch inhibiting amount of a derivative, preferably an ether, ester or urethane derivative, of a TEMPO compound, e.g., 4-hydroxy-tetrahydrocarbylpiperidin-1-oxyl. The scorch inhibitors of this invention perform as well, if not better, than their 4-hydroxy-tetrahydrocarbylpiperidin-1-oxyl counterparts in similar polymer compositions and under similar conditions in terms of scorch inhibition and ultimate degree of crosslinking, but exhibit less volatility and less migration within the polymer composition.
摘要:
Crosslinked, melt-shaped articles are manufactured by a process that does not require the use of post-shaping external heat or moisture, the process comprising the steps of: A. Forming a crosslinkable mixture of a 1. Organopolysiloxane containing one or more functional end groups; and 2. Silane-grafted or silane-copolymerized polyolefin; and B. Melt-shaping and partially crosslinking the mixture; and C. Cooling and continuing crosslinking the melt-shaped article. Crosslinking is promoted by the addition of a catalyst to the mixture before or during melt-shaping or to the melt-shaped article.
摘要:
A molded or extruded article, e.g., an electrical part or shielded cable, comprises at least one insulation layer and at least one semiconductive layer, the semiconductive layer thick and comprising in weight percent: A. 1 to 30 wt % of conductive filler; B. 10 to 90 wt % of a non-olefin elastomer; C. 10 to 90 wt % of an olefin elastomer; and D. Optionally, 0.5 to 2.5 wt % of peroxide. Carbon black and/or metal particulates or powder typically comprise the filler, silicone or urethane rubber the non-olefin elastomer, and EPR or EPDM the olefin elastomer.
摘要:
Silicone-thermoplastic polymer reactive blends and copolymer products are prepared using economical post-reactor reactive mixing, e.g., extrusion. The procedure is based on the ring-opening polymerization of cyclic siloxanes within a thermoplastic polymer matrix. In a preferred mode, the thermoplastic polymer is a polyolefin, optionally containing silane groups that are available for reaction with the silicone polymer that is formed in situ. The resulting materials provide hybrid performance that can extend the range of applications beyond those which are served by thermoplastic polymers or silicones alone, or their physical blends.