DETAILED DESCRIPTION OF THE INVENTION As indicated above, the present invention relates to a novel crosslinkable polyethylene-based composition having superior long term physical properties.
Polymers useful for this invention are thermoplastic polymers of ethylene.
Polyethylene homopolymers, ethylene copolymers, and a mixture of both are suitable for the crosslinkable compositions of this invention.
The olefin polymer used in this invention, may be an ethylene homopolymer or ethylene copolymer comprised of a major part of ethylene monomer.
Typically at least about 75% by weight of ethylene monomer will be used.
Useful monomers for a minor part of the polyethylene-based resin include a C3-C8 alpha-olefin, typically an acyclic straight or branched chain olefin such as octene, hexene or butene.
Polyethylene homopolymer and ethylene copolymer compositions for rotomolding applications, are well known and described in U.
S.
Pat.
Nos.
3,876,613 and 3,974,114, and European Patent Application 87210.
Preferred properties of the polyethylene base resin include a melt index of from about 10 to 50, preferably 10 to 30, gm/10 minutes as determined by ASTM D1238, condition "E".
A suitable density is in the range of about 0.
92 to 0.
97, preferably 0.
93 to 0.
96, gm/cc as determined by the ASTM 1505 testing procedure.
Suitable crosslinking compounds are described in U.
S.
Pat.
No.
3,214,422, issued to Mageli et al.
These compounds are acetylenic diperoxy compounds and include well known hexynes and octynes.
Useful organic peroxide initiators include the following: 2,7-dimethyl-2,7-di(t-butylperoxy)octadiyne-3,5 2,7-dimethyl-2,7-di(peroxyethylcarbonate)octadiyne-3,5 3,6-dimethyl-3,6-di(peroxyethylcarbonate)octyne-4 3,6-dimethyl-3,6-di(t-butylperoxy)octyne-4 2,5-dimethyl-2,5-di(peroxybenzoate)hexane-3 2,5-dimethyl-2,5-di(peroxy-n-propyl carbonate)hexane-3 2,5-dimethyl-2,5-di(peroxyisobutylcarbonate)hexane-3 2,5-dimethyl-2,5-di(peroxyethylcarbonate)hexane-3 2,5-dimethyl-2,5-di(alpha-cumylperoxy)hexane-3 2,5-dimethyl-2,5-di(peroxy beta-chloroethylcarbonate)hexane-3, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane-3
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Adhesives and Rubbers 
