The present disclosure relates to a purification method of a polymerization solvent used in and recovered from the preparation of a polyolefin resin, which can effectively remove impurities, in particular polyolefin wax, from the polymerization solvent to obtain a purified polymerization solvent with high purity, and can improve energy efficiency.

The present disclosure relates to a purification method of a polymerization solvent used in and recovered from the preparation of a polyolefin resin, which can effectively remove impurities, in particular polyolefin wax, from the polymerization solvent to obtain a purified polymerization solvent with high purity, and can improve energy efficiency.

The present invention relates to a process for producing a polymer composition comprising the steps of: (A) polymerising, in a first polymerisation reactor in a first solvent,a first olefin monomer having two or more carbon atoms, in the presence of a first polymerisation catalyst for producing a first solution comprising a first polymer of the first olefin monomer and the first solvent; (B) withdrawing a first stream of the first solution from the first polymerisation reactor; (C) passing the first stream of the first solution into a first separator wherein a first liquid phase comprising the polymer and a first vapour phase coexist; (D) withdrawing a first vapour stream and a first concentrated solution stream comprising the polymer from the first separator; (E) passing at least a part of the first vapour stream to a first fractionator; (F) withdrawing a first overhead stream and a first bottom stream from the first fractionator; (G) recovering at least a part of the first overhead stream as a first recycle stream and passing it to the first polymerisation reactor; (H) passing the first concentrated solution stream from the first separator (4) to a second separator (8) wherein a second liquid phase comprising the polymer and a second vapour phase coexist; (I) withdrawing a second vapour stream and a second concentrated solution stream comprising the polymer from the second separator; (J) passing at least a part of the second pour stream to a second fractionator; (K) withdrawing a second overhead stream and a second bottom stream from the second fractionator; (L) recovering at least a part of the second overhead stream as a second recycle stream and passing it to the first polymerisation reactor; (M) passing the second concentrated solution stream from the second separator to a third separator wherein a third liquid phase comprising the polymer and a third vapour phase coexist; characterised in that the mass flow rate of the first recycle stream is at least 80% of the mass flow rate of the first vapour stream and the mass flow rate of the second recycle stream is at least 70% of the mass flow rate of the second vapour stream.

The present invention relates to a process for producing a polymer composition comprising the steps of: (A) polymerising, in a first polymerisation reactor in a first solvent,a first olefin monomer having two or more carbon atoms, in the presence of a first polymerisation catalyst for producing a first solution comprising a first polymer of the first olefin monomer and the first solvent; (B) withdrawing a first stream of the first solution from the first polymerisation reactor; (C) passing the first stream of the first solution into a first separator wherein a first liquid phase comprising the polymer and a first vapour phase coexist; (D) withdrawing a first vapour stream and a first concentrated solution stream comprising the polymer from the first separator; (E) passing at least a part of the first vapour stream to a first fractionator; (F) withdrawing a first overhead stream and a first bottom stream from the first fractionator; (G) recovering at least a part of the first overhead stream as a first recycle stream and passing it to the first polymerisation reactor; (H) passing the first concentrated solution stream from the first separator (4) to a second separator (8) wherein a second liquid phase comprising the polymer and a second vapour phase coexist; (I) withdrawing a second vapour stream and a second concentrated solution stream comprising the polymer from the second separator; (J) passing at least a part of the second pour stream to a second fractionator; (K) withdrawing a second overhead stream and a second bottom stream from the second fractionator; (L) recovering at least a part of the second overhead stream as a second recycle stream and passing it to the first polymerisation reactor; (M) passing the second concentrated solution stream from the second separator to a third separator wherein a third liquid phase comprising the polymer and a third vapour phase coexist; characterised in that the mass flow rate of the first recycle stream is at least 80% of the mass flow rate of the first vapour stream and the mass flow rate of the second recycle stream is at least 70% of the mass flow rate of the second vapour stream.

In a water-absorbent resin production apparatus for producing a water-absorbent resin by polymerizing a water-soluble ethylenically unsaturated monomer, a water-absorbent resin powder obtained by drying a water-absorbent resin composition with a dryer passes through a first powder flow path pipe, is discharged therefrom toward a classifier while a flow rate is regulated so as to a predetermined value by a powder flow rate regulating discharge member composed of a hopper and a rotary valve, and is classified by the classifier. In the water-absorbent resin production apparatus, a collector for collecting a powder aggregate composed of aggregated particles of the water-absorbent resin powder is disposed in the first powder flow path pipe. Accordingly, a water-absorbent resin in the form of a particulate powder from which the powder aggregate is removed can be produced at a high production efficiency.

In a water-absorbent resin production apparatus for producing a water-absorbent resin by polymerizing a water-soluble ethylenically unsaturated monomer, a water-absorbent resin powder obtained by drying a water-absorbent resin composition with a dryer passes through a first powder flow path pipe, is discharged therefrom toward a classifier while a flow rate is regulated so as to a predetermined value by a powder flow rate regulating discharge member composed of a hopper and a rotary valve, and is classified by the classifier. In the water-absorbent resin production apparatus, a collector for collecting a powder aggregate composed of aggregated particles of the water-absorbent resin powder is disposed in the first powder flow path pipe. Accordingly, a water-absorbent resin in the form of a particulate powder from which the powder aggregate is removed can be produced at a high production efficiency.

Polymer particles excellent in uniform dispersibility and the use thereof are provided. The polymer particles contain a surfactant, and have a coefficient of variation in the volume-based particle diameter distribution in the range from not less than 13.0% to not more than 25.0%. When 15.0 g of water is added to 5.0 g of the polymer particles so as to disperse the polymer particles in the water by performing a dispersion treatment for 60 minutes using an ultrasonic cleaner, and furthermore when an obtained dispersion liquid is put into a centrifuge tube with an inside diameter of 24 mm so as to be centrifuged, by a centrifugal separator, under conditions that K factor is 6943 and a rotating time is 30 minutes to recover a supernatant, a concentration of non-volatile components in the obtained supernatant is less than 3.5 wt. %.

Polymer particles excellent in uniform dispersibility and the use thereof are provided. The polymer particles contain a surfactant, and have a coefficient of variation in the volume-based particle diameter distribution in the range from not less than 13.0% to not more than 25.0%. When 15.0 g of water is added to 5.0 g of the polymer particles so as to disperse the polymer particles in the water by performing a dispersion treatment for 60 minutes using an ultrasonic cleaner, and furthermore when an obtained dispersion liquid is put into a centrifuge tube with an inside diameter of 24 mm so as to be centrifuged, by a centrifugal separator, under conditions that K factor is 6943 and a rotating time is 30 minutes to recover a supernatant, a concentration of non-volatile components in the obtained supernatant is less than 3.5 wt. %.

The present disclosure concerns a bulk polymerization process for the preparation of high heat performance copolymer resins with a reduced amount of oligomer byproduct. The method can comprise isolating oligomer byproduct and introducing the oligomer byproduct into the reactant mixture for the bulk polymerization process.

In a water-absorbent resin production apparatus for producing a water-absorbent resin by polymerizing a water-soluble ethlenically unsaturated monomer, a water-absorbent resin powder obtained by drying a water-absorbent resin composition with a dryer passes through a first powder flow path pipe, is discharged therefrom toward a classifier while a flow rate is regulated so as to a predetermined value by a powder flow rate regulating discharge member composed of a hopper and a rotary valve, and is classified by the classifier. In the water-absorbent resin production apparatus, a collector for collecting a powder aggregate composed of aggregated particles of the water-absorbent resin powder is disposed in the first powder flow path pipe. Accordingly, a water-absorbent resin in the form of a particulate powder from which the powder aggregate is removed can be produced at a high production efficiency.