Disclosed is a method for producing a polyolefin including: (1) a step (1) of polymerizing one or more olefins in solution polymerization or slurry polymerization in the presence of a polymerization catalyst to produce a polymer solution, (2) a step (2) of taking out the polymer solution obtained in the step (1), and adding a catalyst deactivator in the polymer solution to deactivate the polymerization catalyst, and (3) a step (3) of removing volatile components in vacuum from the polymer solution where the polymerization catalyst has been deactivated, and including, between the step (2) and the step (3), a step of adding an additive to the polymer solution when the water concentration in the polymer solution is 5 ppm by mass or less.

The present disclosure relates to a preparation method of a porous super absorbent polymer including the steps of preparing a monomer neutralized solution by adding an internal cross-linking agent, an initiator, an inorganic filler, and a nonionic surfactant to a neutralized solution obtained by neutralizing at least 80 mol % of a water soluble ethylene-based unsaturated monomer containing acidic groups; high-shear mixing the monomer neutralized solution; preparing a hydrogel polymer from the high-shear mixed monomer neutralized solution by thermal polymerization or photopolymerization; and preparing a base resin powder by drying, pulverizing, and classifying the hydrogel polymer.

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 provides an ethylene polymer having a viscosity average molecular weight of 10010.sup.4 or more and 1,00010.sup.4 or less, in which a ratio between an isothermal crystallization time at 125 C. and an isothermal crystallization time at 123 C. obtained under specific isothermal crystallization time measurement conditions is 3.5 or more and 10.0 or less, and a degree of crystallization obtained using a differential scanning calorimeter (DSC) is 40% or more and 75% or less.

The present invention provides an ethylene polymer having a viscosity average molecular weight of 10010.sup.4 or more and 1,00010.sup.4 or less, in which a ratio between an isothermal crystallization time at 125 C. and an isothermal crystallization time at 123 C. obtained under specific isothermal crystallization time measurement conditions is 3.5 or more and 10.0 or less, and a degree of crystallization obtained using a differential scanning calorimeter (DSC) is 40% or more and 75% or less.

The invention relates to a method for producing a hydrocarbon resin, in which method a monomer mixture which contains an aromatic component containing indene and/or C.sub.1-4 alkylindene and a cyclic diolefin component containing a cyclic diolefin compound is polymerized by heating to a polymerization temperature of at least 180? C. to obtain a product stream containing hydrocarbon resin, wherein oligomers which contain units originating from the cyclic diolefin compound and/or units originating from the aromatic component are separated from the product stream and returned to the monomer mixture, and wherein the hydrocarbon resin is heated in an annealing step to a temperature of 150? C. to 300? C. for a period of 15 minutes to 240 hours. The invention also relates to a hydrocarbon resin that is obtainable by the method, to a hydrogenated hydrocarbon resin, and to the use of the hydrocarbon resin and the hydrogenated hydrocarbon resin.

The invention relates to a method for producing a hydrocarbon resin, in which method a monomer mixture which contains an aromatic component containing indene and/or C.sub.1-4 alkylindene and a cyclic diolefin component containing a cyclic diolefin compound is polymerized by heating to a polymerization temperature of at least 180? C. to obtain a product stream containing hydrocarbon resin, wherein oligomers which contain units originating from the cyclic diolefin compound and/or units originating from the aromatic component are separated from the product stream and returned to the monomer mixture, and wherein the hydrocarbon resin is heated in an annealing step to a temperature of 150? C. to 300? C. for a period of 15 minutes to 240 hours. The invention also relates to a hydrocarbon resin that is obtainable by the method, to a hydrogenated hydrocarbon resin, and to the use of the hydrocarbon resin and the hydrogenated hydrocarbon resin.

A method for removing metallic foreign matter from a fluororesin and a method for producing a fluororesin with reduced metallic foreign matter, which methods include applying a magnetic field to a fluororesin with a magnet while dropping the fluororesin by gravity to thereby remove metal, wherein the methods provide a screen made of a magnetic material in a flow path of the fluororesin dropped by gravity, and when the fluororesin passes through the screen, the screen is not vibrated.

The present invention provides a method for depth removal of a volatile organic compound (VOC) in polymer resins and products thereof by means of a steam distillation method and apparatus thereof and significantly reducing the odor of the polymer resins and products thereof. The method provided in the present invention can further remove residual inorganic ash in the polymer resins. In the method, saturated steam at a certain temperature continuously keeps in contact with materials for a certain period of time, the VOC and an inorganic small molecule (ash) adsorbed on the surface of a polymer and wrapped inside the polymer are promoted to be enriched in a gas phase or a liquid phase and discharged, so as to reduce the VOC and ash in polymer materials, and the odor of the polymer resins or materials is decreased to a better level.