National Institute of Clean-and-low-carbon Energy

Shenhua Group Corporation Limited

Xuelian Chen

Wenbin Liang

Yanhua Niu

Shih-yaw Lai

A crosslinked polyethylene composition comprising 100 parts by weight of polyethylene, 0.05-5 parts by weight of crosslinking agent, 0.03-3 parts by weight of crosslinking aid. Polyethylene is a copolymer, homopolymer and/or a mixture thereof. The crosslinking agent is an organic peroxide having a half-life period longer than 3 minutes at 190&#xb0; C. and/or a multi-membered heterocyclic alkane consisting of 3 to 6 carbon atoms and 3 to 6 oxygen atoms and/or a derivative thereof. The crosslinking aid is an organic substance containing allyl, maleimido, (meth)acrylate group and/or a polymer having a vinyl content higher than 50%. Preferably, the crosslinking aid is triallyl isocyanate (TAIC), triallyl cyanurate (TAC) or a mixture thereof. The crosslinked polyethylene composition has a crosslinking efficiency index &#x3e;1000 Nm/g and a &#x3b4; torque value &#x3e;15 Nm at 220&#xb0; C., and has a high safe processing temperature and long crosslinking delay, and therefore is particularly suitable for rotationally molded products.

Crosslinked polyethylene composition

Disclosed in the present invention is a crosslinked polyethylene composition having improved processability comprises: 100 parts by weight of polyethylene, 0.03-5 parts by weight of crosslinking agent, 0.03-5 parts by weight of crosslinking promoter, and 0.01-1.5 parts by weight of free radical inhibitor, wherein the polyethylene is a copolymer and/or homopolymer containing at least 90 wt. % of vinyl and at least one C-C&#x3b1;-alkenyl, and has a density in the range of 0.920-0.970 g/cm, a melt index in the range of 2.5-17.5 g/10 min; the crosslinking agent is a peroxide crosslinking agent; the crosslinking promoter is an organic substance containing maleimido, (meth)acrylate group, and/or allyl, and/or a polymer containing more than 50% of vinyl; the free radical inhibitor is an organic antioxidant, a quinhydrone and/or a substituted quinhydrone. The crosslinked polyethylene composition of the present invention has a crosslinking efficiency index of more than 1,100 Nm/g and a &#x3b4; torque value of more than 10 Nm at the temperature of 200&#xb0; C., a significantly higher safety process temperature and a significantly improved crosslinking retardation time compared to the conventional crosslinked polyethylene composition, which make it especially be suitable for the production of rotational molding articles.

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Beijing, China

Xuelian Chen