Abstract: A method of preventing polymer scale deposition in a polymerization vessel during polymerization of a monomer having an ethylenically double bond, wherein said polymerization is carried out in a polymerization vessel of which the inner wall has been previously first coated with(A) a coating solution comprising a condensate of an aromatic compound and at least one member selected from the group consisting of metal compounds and inorganic colloids, and the coating thus formed has been then coated with(B) a coating solution comprising at least one member selected from the group consisting of anionic polymeric compounds, amphoteric polymeric compounds and hydroxyl group-containing polymeric compounds; and a polymerization vessel having a coating thus formed. According this method, polymer scale deposition on the inner wall, etc. of the polymerization vessel can be effectively prevented.

Abstract: A primer comprising at least one selected from the group consisting of dyes and pigments, and, optionally, at least one selected from the group consisting of an organosilicon compound represented by Formula (I): ##STR1## wherein R.sup.1 represents a monovalent hydrocarbon group; R.sup.2 represents a substituted or unsubstituted monovalent hydrocarbon group; R.sup.3 represents X-- or X-R.sup.4 --, where X represents a monovalent hydrocarbon group containing an epoxy group, etc., and R.sup.4 represents a saturated divalent hydrocarbon group; and n is an integer of 0 to 2,and a partial hydrolyzate thereof. This primer can import a good adhesion to so-called hardly adherable materials such as polyolefin plastics.

Abstract: A method of preventing polymer scale deposition in a polymerization vessel during polymerization of a monomer having an ethylenically double bond, wherein said polymerization is carried out in a polymerization of which the inner wall has been previously coated with a coating solution comprising:(A) an aromatic amine-based condensate,(B) at least one member selected from the group consisting of alkali metal salts and ammonium salts of a sulfonation product prepared by sulfonation of an aromatic amine-based condensate, and(C) at least one member selected from the group consisting of metal compounds, inorganic colloids, dyes and pigments; a scale preventive agent comprising the components (A), (B) and (C); and a polymerization vessel having a coating comprising the scale preventive agent. According the method, polymer scale deposition on the inner wall, etc. of the polymerization vessel can be effectively prevented.

Abstract: A method of preventing polymer scale formation in a polymerization vessel during the polymerization of a monomer having an ethylenically double bond, wherein said polymerization is carried out in a polymerization vessel in which its inner wall surface has been previously coated with a coating solution containing (A) at least one member selected from the group consisting of particular anionic dyes, and alkali metal salts and ammonium salts of a sulfonated product obtained by sulfonation of a condensate of a particular aromatic amine compound with a particular aromatic nitro compound, and (B) a particular cationic dye and having a pH of more than 7, and then dried to form a coating. This method can effectively prevent scale formation in the polymerization of extensive monomers having an ethylenically double bond, so that 100 or more polymerization runs can be repeated without formation of polymer scale.

Abstract: A method of preventing polymer scale deposition in polymerization of a monomer having an ethylenically double bond, wherein said polymerization is carried out in a polymerization vessel in which its inner wall surface has been previously coated with a coating solution comprising:(A) a condensate of a phenolic hydroxy group-containing compound,(B) at least one member selected from the group consisting of metal compounds and inorganic colloids, and(C) at least one member selected from the group consisting of dyes and pigments. This method makes it possible to prevent polymer scale deposition regardless of polymerization conditions such as the kind of monomers, the type of polymerization vessel, etc.

Abstract: A method of preventing polymer scales from sticking in a polymerization vessel during the polymerization of a monomer having an ethylenically double bond, wherein said polymerization is carried out in a polymerization vessel of which the inner wall and other parts with which said monomer comes into contact during polymerization are previously first coated with (a) a coating solution comprising a cationic dye and the resulting coating is then coated with (b) a coating solution comprising at least one component selected from the group consisting of anionic polymeric compounds, amphoteric polymeric compounds and hydroxyl group-containing organic compounds. Polymer scale formation can be effectively prevented.

Abstract: A process for production of a vinyl polymer by suspension polymerization or emulsion polymerization of at least one kind of vinyl monomer in an aqueous medium is disclosed.In this process, the polymerization is carried out in a polymerizer, the inner wall surface and portions of the auxiliary equipment thereof which may come into contact with the monomer during polymerization having a surface roughness of not greater than 5 .mu.m and being previously coated with a scaling preventive comprising at least one selected from dyes, pigments and aromatic or heterocyclic compounds having at least 5 conjugated .pi. bonds. According to this process, scaling on the inner wall surface of a polymerizer, etc. during polymerization can be prevented effectively and surely.

Abstract: This process is a process for production of a vinyl chloride polymer by suspension polymerization or emulsion polymerization of vinyl chloride monomer or a mixture of vinyl chloride monomer with a vinyl monomer copolymerizable with said vinyl chloride monomer in an aqueous medium, characterized in that the polymerization is carried out in a polymerizer, the inner wall surface and portions of the auxiliary equipment thereof which may come into contact with the monomer during polymerization being previously coated with a scaling preventive comprising at least one selected from dyes, pigments and aromatic or heterocyclic compounds having at least 5 conjugated .pi. bonds, while controlling the chloride ion concentration in the reaction mixture to not higher than 100 ppm. According to said process, scaling onto the inner wall surface of a polymerizer, etc. during polymerization can be prevented effectively and surely.

Abstract: The invention provides an efficient method for preventing polymer scale deposition on the reactor walls in the suspension or emulsion polymerization of an ethylenically unsaturated monomer, e.g. vinyl chloride and styrene, by coating the reactor walls, prior to introduction of the polymerization mixture, with an aqueous coating solution containing (a) a silicic acid compound, e.g. colloidal silicic acid, and (b) a phosphorous compound, e.g. phytic acid and polyphosphoric acid, in a specified weight proportion followed by drying.

Abstract: The invention provides a novel method for preventing deposition of polymer scale on the walls of a polymerization reactor in the course of polymerization of various ethylenically unsaturated monomers such as the suspension polymerization of vinyl chloride in an aqueous medium. The method comprises coating the reactor walls with a coating solution containing (a) a polymeric compound having hydroxyl groups such as a polyvinyl alcohol and (b) a silicic acid compound such as water glass followed by drying of the coated surface and washing thereof with water.

Abstract: The invention provides a novel and efficient method for preventing deposition of polymer scale on the reactor walls more or less unavoidable in the course of polymerization of a vinylic monomer or, in particular, in the suspension polymerization of vinyl chloride. The method comprises, prior to polymerization, coating the reactor walls with an aqueous coating solution containing (a) an alkali metal or ammonium salt of a sulfonic acid-type or carboxylic acid-type dye or an organic sulfonic or carboxylic acid having at least one pair of conjugated double bonds in a molecule and (b) a polyvinyl alcohol in a specified proportion, the pH value of the solution being controlled not to exceed 7, followed by drying.

Abstract: The invention provides an efficient method for removing polymer scale deposited on the walls of the polymerization reactor after completion of a polymerization run of an ethylenically unsaturated monomer, e.g. vinyl chloride, in an aqueous medium. The polymer scale adhering to the walls is soaked with a scale-remover solution containing a soluble cellulose derivative, such as ethyl cellulose, hydroxypropyl methyl cellulose and the like, applied thereto and, after standing as wet for a while, washed down easily with water. Certain additives to the solution, e.g. acids, alkalis, paraffins and emulsifying agents, may further enhance the effectiveness of the remover solution.

Abstract: The invention provides a very simple but effective means for preventing surface oxidation of fine metal powders by coating the metal powder with an organic dye. This method of surface-oxidation prevention is particularly useful for the preparation of a so-called plastic magnet which is prepared by uniformly blending a dye-coated fine powder of a magnetic alloy such as a rare earth-cobalt based permanent magnet with a thermoplastic resin such as a nylon or polyphenylene sulfide resin followed by molding the resin-powder blend into a magnet form. In addition to the remarkably improved magnetic properties of the thus prepared plastic magnets as a result of high loading and absence of degradation by oxidation, the danger of spontaneous ignition of the magnet powder in molding can be eliminated almost completely. Surface treatment of the dye-coated magnet powder with a silicone fluid gives further improved results.

Abstract: The invention provides an improved method for preventing polymer scale deposition on the reactor walls, for example, in the suspension polymerization of vinyl chloride by coating the walls prior to introduction of the polymerization mixture with a specific coating composition of which the essential ingredient is a combination of (a) a condensation product of an aromatic amine compound, e.g. aniline or a derivative thereof, and an aromatic nitro compound, e.g. nitrobenzene or a derivative thereof, and (b) a sulfonation product of a condensation product of an aromatic amine compound and an aromatic nitro compound in the form of a salt with an alkali metal or ammonium as dissolved in a solvent.

Abstract: The invention provides a method for preventing deposition of polymer scale on the reactor walls in the polymerization of an ethylenically unsaturated monomer, in particular, by emulsion polymerization. The method comprises coating the reactor walls with a coating composition containing, as the essential components, (A) an organic compound having at least 5 conjugated .pi. bonds in a molecule, (B) a chelating agent and (C) a metal compound capable of producing metal ions having a coordination number of at least 2 which presumably forms a metallic chelate compound with the chelating agent contributing to the formation of a strongly adsorbed layer on the reactor walls. The coating composition may be further admixed with a silicic acid compound such as a colloidal silica.

Abstract: The invention provides a very efficient method with highly durable effect for preventing polymer scale deposition on the reactor walls and other surfaces coming into contact with the monomer during polymerization of an ethylenically unsaturated polymerizable monomer in an aqueous medium such as in the suspension polymerization of vinyl chloride. The method comprises coating the reactor walls, prior to polymerization, with a novel coating material which is a condensation product obtained by the condensation reaction of an aromatic amine compound such as aniline and an aromatic nitro compound such as nitrobenzene in the presence of a mineral acid and a specified condensation catalyst. It is sometimes preferable that the condensation product is basified or treated with an alkali or ammonium compound to be imparted with a modified solubility behavior.

Abstract: The invention provides a novel method for preventing polymer scale deposition on the reactor walls in the polymerization of vinyl chloride, vinylidene chloride, styrene and other ethylenically unsaturated monomers in an aqueous medium. The inventive method comprises coating the reactor walls, piror to polymerization, with an aqueous coating solution containing a water-soluble ionic polymer and a water-soluble ionic dye having counteractive polarity to the polarity of the water-soluble ionic polymer compound. In other words, a water-soluble anionic dye is used as combined with a water-soluble cationic polymer and a water-soluble cationic dye is used as combined with a water-soluble anionic polymer compound.

Abstract: A method for polymerizing vinyl chloride in an aqueous suspension wherein polymer scale is prevented from depositing on walls and other surfaces in contact with monomer in a polymerization reactor. According to the method, one or more compounds selected from iodine salts of alkali metals and alkaline earth metals are added to the polymerization mixture. The effect of this method can be enhanced synergistically by coating a polar organic compound or an organic dye over the surfaces in contact with the monomer.

Abstract: A novel and improved method for polymerizing a vinyl monomer in a polymerization reactor is provided. The inner walls of the polymerization reactor and other surfaces coming into contact with the monomer are coated with an aqueous liquid containing at least one alkali metal or ammonium salt of an anionic dye of the sulfonic carboxylic acid form and having a pH value adjusted not to exceed 7 by aid of a pH adjusting agent, and the thus coated surfaces are dried with heat before the polymerization is conducted. The method serves to greatly reduce the deposition of polymer scale on those surfaces and, consequently, improve the productivity as well as the quality of polymer product.

Abstract: Vinyl chloride monomer or a monomeric mixture composed mainly of vinyl chloride is polymerized in a polymerization vessel having its inner walls and the surfaces of an agitator and other equipment attached thereto coming into contact with the monomer or monomers coated with a metal complex of a polar organic compound and/or an organic dye. This method of polymerization serves to greatly reduce the deposition of polymer scale on those surfaces and produce high quality polymer.