Abstract: A process for preparing vinyl acetate-ethylene copolymers in the form of an aqueous dispersion. The process includes providing an aqueous dispersion of vinyl acetate-ethylene copolymers and subjecting the aqueous dispersion of vinyl acetate-ethylene copolymers to radically initiated emulsion polymerization in a continuously operated tubular-reactor. Where one or more dividing plates bearing liquid-permeable openings that are mounted within the tubular-reactor transverse to the flow direction of the reactor contents.

Abstract: A polymerization reactor for producing aqueous polymer dispersions by radically initiated emulsion polymerization of one or more ethylenically unsaturated monomers in the presence of one or more protective colloids and/or emulsifiers, is cleaned by initially charging an aqueous mixture comprising one or more ethylenically unsaturated monomers, one or more protective colloids and/or emulsifiers, but no oxidation initiator, the proportion of ethylenically unsaturated monomers being 20 to 70% by weight of the aqueous mixture, heating the aqueous mixture to a temperature of 50° C. to 100° C. for 5 minutes to 3 hours, adding one or more initiators and optionally further starting materials, initiating polymerization, removing the aqueous polymer dispersion thus obtained from the polymerization reactor and post-treating the dispersion to remove wall deposits detached during the process.

Abstract: A process for preparing vinyl acetate-ethylene copolymers in the form of an aqueous dispersion. The process includes providing an aqueous dispersion of vinyl acetate-ethylene copolymers and subjecting the aqueous dispersion of vinyl acetate-ethylene copolymers to radically initiated emulsion polymerization in a continuously operated tubular-reactor. Where one or more dividing plates bearing liquid-permeable openings that are mounted within the tubular-reactor transverse to the flow direction of the reactor contents.

Abstract: Aqueous polymer dispersions are produced by radically initiated emulsion polymerization of ethylenically unsaturated monomers in the presence of protective colloids and/or emulsifiers in a continuously operated tubular reactor, characterized in that the direction of flow of the reactor contents is reversed along the longitudinal axis of the reactor over the course of polymerization.

Abstract: Building construction materials containing inorganic hydraulically settable binder(s) and at least one protective colloid-stabilized polyvinyl acetate copolymer having specific ranges of vinyl acetate, vinyl chloride, and ethylene show improved adhesion under widely varying conditions when used in hydraulically setting construction materials, especially after thermal storage conditions.

Abstract: A polymerization reactor for producing aqueous polymer dispersions by radically initiated emulsion polymerization of one or more ethylenically unsaturated monomers in the presence of one or more protective colloids and/or emulsifiers, is cleaned by initially charging an aqueous mixture comprising one or more ethylenically unsaturated monomers, one or more protective colloids and/or emulsifiers, but no oxidation initiator, the proportion of ethylenically unsaturated monomers being 20 to 70% by weight of the aqueous mixture, heating the aqueous mixture to a temperature of 50° C. to 100° C. for 5 minutes to 3 hours, adding one or more initiators and optionally further starting materials, initiating polymerization, removing the aqueous polymer dispersion thus obtained from the polymerization reactor and post-treating the dispersion to remove wall deposits detached during the process.

Abstract: Aqueous polymer dispersions are produced by radically initiated emulsion polymerization of ethylenically unsaturated monomers in the presence of protective colloids and/or emulsifiers in a continuously operated tubular reactor, characterized in that the direction of flow of the reactor contents is reversed along the longitudinal axis of the reactor over the course of polymerization.

Abstract: Polyvinyl acetate copolymers having specific ranges of vinyl acetate, vinyl chloride, and ethylene show improved adhesion under widely varying conditions when used in hydraulically setting construction materials.

Abstract: Polyvinyl acetate copolymers having specific ranges of vinyl acetate, vinyl chloride, and ethylene show improved adhesion under widely varying conditions when used in hydraulically setting construction materials.

Abstract: A method for producing aqueous polymer dispersions by means of radically initiated emulsion polymerisation, in an aqueous medium, of vinyl ester and ethylene, in series-connected polymerisation reactors, wherein in a first discontinuous polymerisation phase at least some of the reactants are introduced into the first polymerisation reactor and the remainder is added in a metered fashion. The reactor is filled up to more than 90% by volume, and at least 90 wt % of the monomers are reacted; in a second continuous polymerisation phase, the reactants are continuously supplied to the first polymerisation reactor and product is continuously withdrawn, and the product is continuously transferred into a second polymerisation reactor, and in the second polymerisation reactor the polymerisation is continued until at least 98 wt % of the monomers used have reacted.

Abstract: A method for producing aqueous polymer dispersions by means of radically initiated emulsion polymerisation, in an aqueous medium, of vinyl ester and ethylene, in series-connected polymerisation reactors, wherein in a first discontinuous polymerisation phase at least some of the reactants are introduced into the first polymerisation reactor and the remainder is added in a metered fashion. The reactor is filled up to more than 90% by volume, and at least 90 wt % of the monomers are reacted; in a second continuous polymerisation phase, the reactants are continuously supplied to the first polymerisation reactor and product is continuously withdrawn, and the product is continuously transferred into a second polymerisation reactor, and in the second polymerisation reactor the polymerisation is continued until at least 98 wt % of the monomers used have reacted.

Abstract: The invention provides a process for preparing polymers based on vinyl ester, ethylene and optionally further comonomers in the form of aqueous polymer dispersions thereof or of water-redispersible polymer powders by means of free-radically initiated continuous emulsion polymerization and optionally drying of the resulting polymer dispersions, characterized in that the emulsion polymerization is carried out in a cascade comprising at least one upstream heat exchanger and at least two downstream pressurized stirred tank reactors connected in series, such that the conversion on leaving the heat exchanger is at least 10% of the overall polymerization conversion.

Abstract: The invention provides a process for preparing polymers based on vinyl ester, ethylene and optionally further comonomers in the form of aqueous polymer dispersions thereof or of water-redispersible polymer powders by means of free-radically initiated continuous emulsion polymerization and optionally drying of the resulting polymer dispersions, characterized in that the emulsion polymerization is carried out in a cascade comprising at least one upstream heat exchanger and at least two downstream pressurized stirred tank reactors connected in series, such that the conversion on leaving the heat exchanger is at least 10% of the overall polymerization conversion.

Abstract: A process for preparing copolymers via free-radical-initiated polymerization of one or more vinyl esters, ethylene, and also, where appropriate, other ethylenically unsaturated monomers copolymerizable therewith, at a pressure of from 5 to 100 bar abs., in an aqueous medium, by emulsion or suspension polymerization, which comprises, after termination of the polymerization, reclaiming residual unreacted ethylene by depressurizing the polymerization reaction mixture to a pressure of from 0.1 to 5 bar absolute, comprising a gas phase containing residual ethylene gas to a pressure of from 2 to 20 bar absolute, absorbing the gas phase into vinyl ester(s), and reusing the resulting solution of ethylene in vinyl esters(s) in a further polymerization.

Abstract: A process for preparing aqueous dispersions or water-redispersible polymer powders of polyvinyl-alcohol-stabilized polymers based on vinyl ester(s), and ethylene, by continuous emulsion polymerization with no seed latex, and optionally drying the dispersion, by a) polymerizing in at least two pressurized reactors in series at a temperature of 40 to 100° C. and a pressure of 5 to 100 bar to a residual monomer content of less than 3% by weight, and continuing polymerizing in an unpressurized reactor at 20 to 60° C. and less than 1.

Abstract: A process for preparing copolymers via free-radical-initiated polymerization of one or more vinyl esters, ethylene, and also, where appropriate, other ethylenically unsaturated monomers copolymerizable therewith, at a pressure of from 5 to 100 bar abs., in an aqueous medium, by emulsion or suspension polymerization, which comprises, after termination of the polymerization, reclaiming residual unreacted ethylene by depressurizing the polymerization reaction mixture to a pressure of from 0.1 to 5 bar absolute, comprising a gas phase containing residual ethylene gas to a pressure of from 2 to 20 bar absolute, absorbing the gas phase into vinyl ester(s), and reusing the resulting solution of ethylene in vinyl esters(s) in a further polymerization.

Abstract: A process for preparing aqueous dispersions or water-redispersible polymer powders of polyvinyl-alcohol-stabilized polymers based on vinyl ester(s), and ethylene, by continuous emulsion polymerization with no seed latex, and optionally drying the dispersion, by

Abstract: The invention relates to a method of producing protective colloid free, aqueous dispersions of vinyl ester co-polymers by radical emulsion polymerization of 40 to 99.5 weight percent vinyl acetate, 0 to 40 weight percent of one or several alkenes, 0 to 40 weight percent of one or several monomers from the group consisting of vinyl esters of C6 to C12 alkyl carboxylic acids, and of (meth)acrylic-acid esters of alcohols with 1 to 12 C atoms and optionally, additional copolymerizable mono- or poly-ethylenically unsaturated monomers. Said method is characterized in that 0.1 to 5 weight percent of one or several emulsifiers are polymerized with a persulfate initiator in the presence of 0.5 to 20 weight percent mono- or poly-ethylenically unsaturated carboxylic acid amides or derivatives thereof. The invention also relates to a method for producing protective colloid-free dispersion powders by spray drying or freeze drying said dispersions.

Abstract: The invention provides thickeners based on carboxyl- and carboxamido-containing addition polymers obtainable by free-radical emulsion or suspension polymerization of: a) from 30 to 70% by weight of carboxyl-containing, ethylenically unsaturated monomers, b) from 10 to 70% by weight of carboxamido-containing, ethylenically unsaturated monomers, and c) from 0.1 to 30% by weight of further ethylenically unsaturated monomers in the presence of at least 5% by weight of one or more water-soluble protective colloids from the group consisting of polyvinyl alcohols, polyvinyl pyrrolidones and (meth)acrylate-(meth)acrylic acid copolymers, the percentages by weight being based in each case on the overall weight of the comonomers.

Abstract: Aqueous dispersions of organopolysiloxanes comprising (A) an organopolysiloxane containing groups which are capable of condensation, (B) a condensation catalyst, (C) an organopolysiloxane resin which is at least partly soluble in organopolysiloxane (A) when present in amounts of up to 50% by weight based on the weight of (A), (D) a compound containing basic nitrogen and (E) polyvinyl alcohol. The aqueous dispersions are prepared by dissolving the organopolysiloxane resin (C) in the organopolysiloxane (A) and then emulsifying the solution with polyvinyl alcohol (E) and water. The stable aqueous dispersions of the present invention cure to form transparent films.