Process for the production of expanded reticulated

专利名称：Process for the production of expanded

reticulated polyethylene

发明人：Saverio Quintavalle,Luciano Gargani申请号：US06/657961申请日：19841005公开号：US04559190A公开日：19851217

摘要：Process for the preparation of bodies of expanded cross-linked polyethylene,with closed cells, comprising the steps of:

< P>melting a polymer of ethylene selected among ethylene homopolymers,copolymers of ethylene with alpha-olefins, copolymers of ethylene with conjugateddiolefins and relevant mixtures;

homogenizing the polymer of ethylene in the molten state with a quantity of from 0.1to 2.5% by weight of a cross-linking agent and with a quantity of from 2 to 25% by weightof an expanding agent, the cross-linking agent and expanding agent having a

decomposition temperature higher than the melting point of the polymer of ethylene,the homogenizing step operating at temperatures of from 130° to 150° C., and for timesof from 5 to 10 minutes;

forming the homogeneous mixture in a solid parallelepiped shape by means ofextrusion and subsequent cooling, or by means of moulding wherein the extrusion ormoulding step is operated at temperatures within the range of from 130° to 150. degree.C. and for times of from 1 to 10 minutes;

placing the solid parallelepiped shaped body inside an air-tight closed container,pressurizing the container by means of an inert gas, and heating the solid parallelepipedshaped body, at a temperature higher than the decomposition temperature of the cross-linking agent and the expanding agent contained therein, wherein this step is operated at170. degree.- 200° C., under 40-70 bar for 20-45 minutes, in the absence, or substantialabsence of expansion, such that expansion is limited to less than about 5%;

depressurizing the container immediately following the foregoing pressurizing andheating step for a time of from 0.5 to 3 minutes, allowing the body to expand to an endvolume smaller than the volume of the container, and recovering the expandedreticulated item from the container.

申请人：AGIP PETROLI S.P.A.,INDUSTRIA ITALIANA PETROLI S.P.A.

代理机构：Morgan, Finnegan, Pine, Foley & Lee

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