Abstract: Polyvinyl chloride reactor wall scale is reduced by conducting the polymerization in the presence of a phenothiazine dimer or higher oligomer made by reacting an aldehyde such as acetaldehyde or benzaldehyde with phenothiazine, or by reacting 2-acetylphenothiazine with formaldehyde.

Abstract: A microsuspension polymerization process for polymerizing vinyl chloride and optional comonomers to polyvinyl chloride and optional copolymers is disclosed which comprises conducting the polymerization in a tubular reaction zone without agitation in the presence of a compound having the formula ##STR1##

Abstract: A composition having the formula ##STR1## wherein n has an average value of one to about five, is disclosed for use in reducing or eliminating the formation of reactor scale during the polymerization of vinyl chloride and comonomers. The composition is prepared by reacting phenothiazine with formaldehyde in the presence of a liquid diluent that is a solvent for the phenothiazine, but a non-solvent for the dimer of phenothiazine and formaldehyde. The process of the invention is preferably conducted in the presence of a strong acid catalyst. The formaldehyde is preferably added slowly to the reaction mixture over the course of the reaction. The product can be filtered and dried.

Abstract: A composition having the formula ##STR1## wherein n has an average value of one to about five, is disclosed for use in reducing or eliminating the formation of reactor scale during the polymerization of vinyl chloride and comonomers. The composition is prepared by reacting phenothiazine with formaldehyde in the presence of a liquid diluent that is a solvent for the phenothiazine, but a non-solvent for the dimer of phenothiazine and formaldehyde. The process of the invention is preferably conducted in the presence of a strong acid catalyst. The formaldehyde is preferably added slowly to the reaction mixture over the course of the reaction. The product can be filtered and dried.

Abstract: A method for improving the clarity of plastisol resin films includes the steps of polymerizing vinyl chloride alone or in the presence of a copolymerizable monomer to yield a latex, and dissolving a nonionic emulsifier in the latex prior to spray drying. The resulting mixture is thereafter spray dried to yield a resin which in turn can be mixed with a plasticizer to form a paste and spread as a thin layer to be fused into a film with heat. Alternatively, the nonionic emulsifier can be added, after spray drying, during preparation of the paste by mixing the emulsifier and plasticizer followed by addition of the resin. The nonionic emulsifiers of the present invention have the formula R--O--(CH.sub.2 CH.sub.2 --O).sub.n H wherein R is selected from the group consisting of fatty acids, polyol fatty acid esters, fatty alcohols, fatty amines, fatty amides, polypropylene oxide and alkylated phenol, and n is an integer ranging from 1 to about 50.