A method for producing an aqueous dispersion of purified polytetrafluoroethylene, the method including: removing or reducing a compound represented by Formula (1) or (2) below from an aqueous dispersion of polytetrafluoroethylene obtained using a hydrocarbon surfactant: Formula (1): (H(CF.sub.2).sub.mCOO).sub.pM.sup.1; or Formula (2): (H(CF.sub.2).sub.nSO.sub.3).sub.qM.sup.2.

Also disclosed is a composition containing polytetrafluoroethylene substantially free from a compound represented by Formula (3) below and a molded body including the composition: Formula (3): (H(CF.sub.2).sub.8SO.sub.3).sub.qM.sup.2.

The present invention relates to a solvent recovery apparatus and a solvent recovery method, and the solvent recovery apparatus and method according to the present application can reduce the used amount of steam in a synthetic rubber production process, and can reduce the used amount of energy by recovering the waste heat discarded through a condenser.

The present invention relates to a solvent recovery apparatus and a solvent recovery method, and the solvent recovery apparatus and method according to the present application can reduce the used amount of steam in a synthetic rubber production process, and can reduce the used amount of energy by recovering the waste heat discarded through a condenser.

Process for the preparation of styrenic polymers having an improved color stability by anionic polymerization wherein the obtained terminated polymer solution is fed to a dispersing device to which water is added, fed to a buffer vessel and then is impregnated in a static mixer by addition of further water, carbon dioxide and one or more stabilizers.

Process for the preparation of styrenic polymers having an improved color stability by anionic polymerization wherein the obtained terminated polymer solution is fed to a dispersing device to which water is added, fed to a buffer vessel and then is impregnated in a static mixer by addition of further water, carbon dioxide and one or more stabilizers.

Process for the preparation of styrenic polymers having an improved color stability by anionic polymerization wherein the obtained terminated polymer solution is fed to a dispersing device to which water is added, fed to a buffer vessel and then is impregnated in a static mixer by addition of further water, carbon dioxide and one or more stabilizers.

Methods according to the present invention decolorize a polymer by mixing a solution of the polymer with a photocatalyst and exposing the mixture to ultraviolet light; by way of non-limiting example, the polymer may be a star polymer and the photocatalyst may be titanium dioxide. Methods according to the present invention also utilize a metal scavenger, in some embodiments a solid-phase metal scavenger, to remove a metal catalyst from a polymer solution; by way of non-limiting example, the metal catalyst may be a tin catalyst. The decolorization methods and the catalyst removal methods of the present invention may be practiced separately, sequentially in any order, or simultaneously.

Methods according to the present invention decolorize a polymer by mixing a solution of the polymer with a photocatalyst and exposing the mixture to ultraviolet light; by way of non-limiting example, the polymer may be a star polymer and the photocatalyst may be titanium dioxide. Methods according to the present invention also utilize a metal scavenger, in some embodiments a solid-phase metal scavenger, to remove a metal catalyst from a polymer solution; by way of non-limiting example, the metal catalyst may be a tin catalyst. The decolorization methods and the catalyst removal methods of the present invention may be practiced separately, sequentially in any order, or simultaneously.

The present invention relates to a method for producing an ethylene-based copolymer, and more particularly, to a method for producing an ethylene-based copolymer capable of increasing process efficiency by preventing plugging and corrosion of a facility. The method for producing an ethylene-based copolymer includes a producing mode and a washing mode of which one is selectively performed. The producing mode includes: a) hyper-compressing primary compressed ethylene, and a mixture including a carboxylic acid-containing comonomer and a polar solvent to produce a compressed material; b) reacting the compressed material to produce a reaction product including an ethylene-based copolymer; and c) separating and recovering unreacted residues from the reaction product and introducing the unreacted residues into the mixture of step a). The washing mode includes: re-supplying the compressed material produced in step a) to step a) as a mixture, without performing step b).

The present invention relates to a method for producing an ethylene-based copolymer, and more particularly, to a method for producing an ethylene-based copolymer capable of increasing process efficiency by preventing plugging and corrosion of a facility. The method for producing an ethylene-based copolymer includes a producing mode and a washing mode of which one is selectively performed. The producing mode includes: a) hyper-compressing primary compressed ethylene, and a mixture including a carboxylic acid-containing comonomer and a polar solvent to produce a compressed material; b) reacting the compressed material to produce a reaction product including an ethylene-based copolymer; and c) separating and recovering unreacted residues from the reaction product and introducing the unreacted residues into the mixture of step a). The washing mode includes: re-supplying the compressed material produced in step a) to step a) as a mixture, without performing step b).