Process for the addition of additives to thermoplastics

Claim 1

In a process for adding to a molten thermoplastic resin or to a solution of a thermoplastic resin solid additives including heat stabilizers, antioxidants, UV-stabilizers, lubricants, antistatic agents, antiblocking agents and corrosion-inhibitors and containing only minor amounts, if any, of finely divided non-melting compounds which additives comprise at least one metal salt of an aliphatic carboxylic acid of at least 10 carbon atoms, said metal being a metal of Group I, II or III of the Periodic Table, said metal salt having a melting point of up to 250°C, the improvement comprising mixing said metal salt of an aliphatic carboxylic acid of at least 10 carbon atoms containing additive composition with at least 10% by weight, based on the weight of said salt, and up to 200% based on said salt, of an amide of a carboxylic acid having at least 10 carbon atoms and a mineral oil which is substantially non-volatile under the process conditions, to form a mixture and heating the mixture to a molten state, at a temperature less than the melting point of said additive and subsequently adding said melt to a themoplastic which is molten or in solution wherein the amount of each additive is up to 1% by weight based on the weight of the thermoplastic resin, wherein the amount of said mineral oil is at least 10% by weight of the total amount of said additives and is up to three times the weight of said additives.