Rubber composite, processing method, sealing element applying composite, and manufacturing method

A rubber composition, comprising a rubber matrix and certain essential components, wherein, said rubber matrix comprises, in parts by weight,

• a branched polyethylene with a content represented as A, 0<A≤100 parts, and
• an EPM and an EPDM, with a total content represented as B, 0≤B<100 parts;
• wherein, with respect to 100 parts by weight of the total amount of said rubber matrix, said certain essential components comprise 2˜20 parts of a cross-linking system, 60˜300 parts of a reinforcing filler, 20˜170 parts of a plasticizer and 3-25 parts of a metal oxide;
• wherein, said branched polyethylene comprises an ethylene homopolymer having a branching degree which is not less than 50 branches/1000 carbons, a weight-average molecular weight which is not less than 50,000, and a mooney viscosity ML (1+4) 125° C. which is not less than 2;
• said cross-linking system comprises a cross-linking agent and an assistant cross-linking agent.