Abstract: In the aqueous polymerization of vinyl chloride and vinylidene chloride polymers and copolymers, the polymer build up normally experienced in many areas of commercial polymerization reactors is reduced, or when such polymer build up does occur it is more readily removed, when these trouble areas in polymerization reactors are coated with a latex-modified portland cement composition, the polymer in said latex containing carboxyl groups and the polymer having a Tg .degree. C. of less than about 40.degree. C., preferably less than about 25.degree. C.

Abstract: Process for preventing build-up in the reactors used in the free radical polymerization of ethylenically unsaturated monomers, and more particularly of vinyl chloride, in which the reactor walls are subjected to heat treatment before the reactors are charged in preparation for the polymerization process.

Abstract: Polymerizations catalyzed by very finely divided lithium.The process is characterized in using lithium having an average particle diameter of less than 2.mu. and preferably of 0.1.mu. or less as a polymerization initiator.The process permits .alpha.-.omega. dilithic oligomers to be obtained.

Abstract: In the aqueous polymerization of vinyl chloride and vinylidene chloride polymers and copolymers in reactors having exposed metal surfaces, undesirable thin polymer build up is noted on the metal surface exposed to the polymerization media. Such polymer build up is substantially reduced if before the polymerization the reactor is first mechanically cleaned to remove visible polymer deposits and then cleaned of organic materials adsorbed on the metal surfaces; and thereafter between polymerization charges as required, by treatment with a hot-alkali detergent mixture to remove organic residues from the surface of said metal surfaces.

Abstract: This invention relates to a polymerization reaction vessel having a coating on the inner surfaces thereof resulting from applying thereto a coating composition containing, as a primary ingredient, a straight chain or branched polyaromatic amine dissolved in an aqueous alkali metal hydroxide solution. When polymerizing olefinic monomers, such as vinyl halides, vinylidene halides, and vinylidene monomers having at least one terminal CH.sub.2 =C< grouping, and mixtures thereof, in the presence of said coating, polymer build-up on the inner surfaces of the reaction vessel is substantially eliminated. Further, multiple charges or batches of polymer can be made in said internally coated reaction vessel without opening the same between charges thus preventing the escape of unreacted monomer to the atmosphere.

Abstract: A reaction vessel having on the internal surfaces thereof a coating containing, as a primary ingredient, a straight chain or branched polyaromatic amine made by the reaction of any one by itself, except the polyhydric phenols, or more than one, of the compounds selected from polyamino benzenes, polyhydric phenols, aminophenols, alkyl-substituted aminophenols, diphenylamines, and alkyl-substituted diphenylamines, which coating is applied to said surfaces from an organic solvent solution. Also included are the above compounds having a halogen substitution on the ring. Further, there is included the process for coating said internal surfaces whereby polymer build-up on said surfaces is substantially eliminated.

Abstract: Vinyl chloride monomer, or a mixture thereof with a copolymerizable monomer or monomers, is bulkpolymerized so that the deposition of polymer scale on the inner walls of the polymerization vessel and other surfaces in contact with the monomer or monomers can be greatly reduced by coating them with phosphoric esters, polyphosphoric esters or their alkali metal salts before the polymerization is commenced. Clean-up operations following each polymerization run are much simplified.

Abstract: The present invention relates to a process for reducing the build-up of polymer on the internal surfaces of a polymerization vessel. This is accomplished according to the invention by coating the internal surfaces of the polymerization vessel with a polymeric material and insolubilizing said material by cross-linking.

Abstract: A method of suspension polymerization, which is effective to prevent the adhesion of scale-form polymer to the inside wall of polymerization vessel, is provided by adding oxalic acid or its salt to the polymerization system consisting of vinyl chloride suspended in aqueous medium.

Abstract: Process for producing a water-soluble polymer comprising polymerizing an ethylenically unsaturated monomer yielding a water-soluble polymer in an aqueous medium in a polymerization vessel, characterized in that the polymerization system is maintained without stirring at least after the polymerization is initiated, the temperature of the polymerization system is permitted to rise on its own accord, and the non-uniformity of temperature distribution between the center and surroundings of the polymerization system due to the temperature rise is eliminated by heating the polymerization system from the outside.

Abstract: The present invention relates to a vessel and a process for polymerizing vinyl chloride in suspension. The vessel the inner surfaces of which consist of stainless steel or are plated with a noble metal comprises at least one cathode in contact with the reaction medium and insoluble therein and as anode the metallic inner surface of the vessel, the cathode and anode being connected over an external source of current. The polymerization is carried out with electrolytic generation of hydrogen and oxygen from the polymerization medium. The polymerization vessel and process according to the invention suppress completely or substantially the formation of wall deposits.

Abstract: The formation of polymer on the surfaces of the reactor equipment in the commercial production of polyvinyl chloride and copolymers thereof is avoided by employing equipment whose surfaces which contact the monomer are formed of substantially pure nickel.

Abstract: Vinyl chloride monomer, or a monomeric mixture comprising vinyl chloride as a main component and other monomers co-polymerizable therewith in an aqueous reaction medium, is polymerized in a polymerization vessel. All of the surfaces of the inside walls of the vessel and the agitator blades, the baffle plates and the like with which the vessel is equipped, are coated prior to the polymerization with at least one of a specific class of nitrogen-containing aromatic heterocyclic compounds. Not only is the deposition of polymer scale surprisingly reduced, but also the polymer thus obtained has good physical and chemical properties.

Abstract: There is disclosed a method for handling acrylamide aqueous solutions with safety wherein acrylamide aqueous solutions obtained through catalytic hydration reaction of acrylonitrile are handled using utensils made from phenol resin, polyethylene, polypropylene, polyvinylchloride resin or fluorine-containing resin or glass or using such utensils that are provided with linings formed by these materials.