Method for inhibiting corrosion-causing tendency and coloration of halogen-containing olefin resins with hydrotalcite

In a method for inhibiting the corrosion-causing tendency and coloration of an olefin polymer or copolymer selected from the group consisting of polyethylene, polypropylene, poly(1-butene), poly(4-methyl-1-pentene), an ethylene-propylene copolymer and a copolymer of at least one alpha-olefin with a diene, said olefin polymer or copolymer containing a halogen component, by incorporating about 0.01 to about 5 parts by weight of a hydrotalcite in the halogen component-containing olefin polymer or copolymer, the improvement which comprises mixing the olefin polymer or copolymer, containing a halogen component attributed to a polymerization catalyst and/or to post-halogenation, with a hydrotalcite of the formula

• Mg.sub.1-x Al.sub.x (OH).sub.2 A.sub.x/n.sup.n-.mH.sub.2 O
• wherein 0<x.ltoreq.0.5, m is a positive number, and A.sup.n- represents an anion having a valence of n, or with a product resulting from the surface-coating of said hydrotalcite with an anionic surface-active agent selected from the group consisting of an alkali metal salt of a fatty acid of the formula RCOOM in which R is an alkyl group having 3 to 40 carbon atoms and M represents an alkali metal atom, an alkali metal salt of an alkylsulfate of the formula ROSO.sub.3 M in which R and M are as defined above, an alkali metal salt of an alkylsulfonate of the formula RSO.sub.3 M in which R and M are as defined above, an alkali metal salt of an alkylarylsulfonate of the formula R-aryl-SO.sub.3 M in which R and M are as defined above and aryl represents phenyl, naphthyl or tolyl, and an alkali metal salt of a sulfosuccinic ester of the formula ##STR2## in which R and M are as defined above, said hydrotalcite having (i) a BET specific surface area of not more than 30 m.sup.2 /g, and
• (ii) an average secondary particle size of not more than 3 microns.