The present invention provides polymer particles capable of being dissolved in a dissolving medium without generating an unmixed lump and capable of uniformly improving the viscosity of a composition, and a thickener using the polymer particles. The polymer particles of the present invention have a number average particle diameter of 1 to 50 .Math.m and a coefficient of variation in a number-based particle size distribution of 30% or more, wherein where the weight average molecular weight of the whole polymer particles is defined as A, the weight average molecular weight of small particles having a cumulative number percentage of 5% or less counted from the smaller diameter side in the number-based particle size distribution of the polymer particles is defined as B, and the weight average molecular weight of large particles having a particle diameter of 5 times or more the number average particle diameter of the polymer particles is defined as C, polymer particles satisfy the following formulas (1) and (2).

[00001]$0.90\le \left(\text{B}/\text{A}\right)<1.0$

[00002]$\left(\text{C}/\text{B}\right)<1.25$

A method for producing a hollow fine particulate containing a fluorine-containing resin and having a large average particle size. The method includes dispersing a solution containing a fluorine-containing monomer, a phase separation promoter, and a non-polymerizable solvent into water to provide a dispersion, and polymerizing the fluorine-containing monomer to provide a hollow fine particulate containing a fluorine-containing resin.

The present disclosure relates to a method for preparing a copolymer, a copolymer prepared therefrom, and a thermoplastic resin composition including the copolymer. The method includes introducing and polymerizing an aromatic vinyl-based monomer, a vinyl cyan-based monomer, and an imide-based monomer, wherein the imide-based monomer is introduced at once in an amount of 1 wt % to 24 wt % before the start of polymerization, and is continuously introduced in an amount of 76 wt % to 99 wt % from the start of the polymerization.

A method for producing a vinyl polymer including a polymerization step of using a composition including a microcapsule and polymerizing a vinyl monomer by radical reaction to produce a vinyl polymer, in which the microcapsule has a core/shell structure, and the shell includes a water-soluble polymer and the core includes an organic peroxide. The water-soluble polymer is preferably at least one water-soluble polymer selected from the group consisting of polyvinyl alcohol, cellulose derivatives, gelatin, poly(meth)acrylic acid derivatives, polyvinylpyrrolidone, and polyethylene oxide.

Provided is a suspension comprising liquid droplets dispersed in an aqueous medium, wherein said droplets comprise (a) one or more water-insoluble compounds, and (b) a vinyl polyelectrolyte (PED) having a polarity, and wherein said aqueous medium comprises a polyelectrolyte (PEW) having a polarity that is opposite to the polarity of said polyelectrolyte (PED). Also provided are a method of making such a suspension and a method using such a suspension in a process of suspension polymerization.

Composition comprising at least one vinyl halide polymer and 0.1 to 5% by weight, relative to the weight of the vinyl halide polymer, of at least one polymer of at least one acrylic ester obtained by polymerization in solution in a liquid medium comprising at least one chain transfer agent chosen among the C.sub.3-C.sub.20 hydrocarbons containing at least one secondary alcohol function. Process for its manufacture, article obtained starting from this composition and use of this composition for manufacturing sheets and films via calendaring or for manufacturing profiles by extrusion. Process for the manufacture of a polymer of at least one acrylic ester which can be used in the composition.

Composition comprising at least one vinyl halide polymer and 0.1 to 5% by weight, relative to the weight of the vinyl halide polymer, of at least one polymer of at least one acrylic ester obtained by polymerization in solution in a liquid medium comprising at least one chain transfer agent chosen among the C.sub.3-C.sub.20 hydrocarbons containing at least one secondary alcohol function. Process for its manufacture, article obtained starting from this composition and use of this composition for manufacturing sheets and films via calendaring or for manufacturing profiles by extrusion. Process for the manufacture of a polymer of at least one acrylic ester which can be used in the composition.

The present invention relates to a process for producing a multimodal polyethylene composition in the reactor system according to the invention, comprising; (a) polymerizing ethylene in an inert hydrocarbon medium in the first reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen in an amount of 0.1-95% by mol with respect to the total gas present in the vapor phase in the first reactor to obtain a low molecular weight polyethylene or a medium molecular weight polyethylene; (b) removing in the hydrogen removal unit 98.0 to 99.8% by weight of the hydrogen comprised in a slurry mixture obtained from the first reactor at a pressure in the range of 103-145 kPa (abs) and transferring the obtained residual mixture to the second reactor; (c) polymerizing ethylene and optionally C.sub.4 to C.sub.12 α-olefin comonomer in the second reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and in the presence of hydrogen in an amount obtained in step (b) to obtain a first high molecular weight polyethylene or a first ultra high molecular weight polyethylene in the form of a homopolymer or a copolymer and transferring a resultant mixture to the third reactor; and (d) polymerizing ethylene, and optionally α-olefin comonomer in the third reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen, wherein the amount of hydrogen in the third reactor is in a range of 1-70% by mol, preferably 1-60% by mol with respect to the total gas present in the vapor phase in the third reactor or optionally substantial absence of hydrogen to obtain a second high molecular weight polyethylene or a second ultra high molecular weight polyethylene homopolymer or copolymer; and a multimodal polyethylene composition obtainable this way.

The present invention relates to a process for producing a multimodal polyethylene composition in the reactor system according to the invention, comprising; (a) polymerizing ethylene in an inert hydrocarbon medium in the first reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen in an amount of 0.1-95% by mol with respect to the total gas present in the vapor phase in the first reactor to obtain a low molecular weight polyethylene or a medium molecular weight polyethylene; (b) removing in the hydrogen removal unit 98.0 to 99.8% by weight of the hydrogen comprised in a slurry mixture obtained from the first reactor at a pressure in the range of 103-145 kPa (abs) and transferring the obtained residual mixture to the second reactor; (c) polymerizing ethylene and optionally C.sub.4 to C.sub.12 α-olefin comonomer in the second reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and in the presence of hydrogen in an amount obtained in step (b) to obtain a first high molecular weight polyethylene or a first ultra high molecular weight polyethylene in the form of a homopolymer or a copolymer and transferring a resultant mixture to the third reactor; and (d) polymerizing ethylene, and optionally α-olefin comonomer in the third reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen, wherein the amount of hydrogen in the third reactor is in a range of 1-70% by mol, preferably 1-60% by mol with respect to the total gas present in the vapor phase in the third reactor or optionally substantial absence of hydrogen to obtain a second high molecular weight polyethylene or a second ultra high molecular weight polyethylene homopolymer or copolymer; and a multimodal polyethylene composition obtainable this way.

The present invention relates to a process for producing a multimodal polyethylene composition in the reactor system according to the invention, comprising; (a) polymerizing ethylene in an inert hydrocarbon medium in the first reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen in an amount of 0.1-95% by mol with respect to the total gas present in the vapor phase in the first reactor to obtain a low molecular weight polyethylene or a medium molecular weight polyethylene; (b) removing in the hydrogen removal unit 98.0 to 99.8% by weight of the hydrogen comprised in a slurry mixture obtained from the first reactor at a pressure in the range of 103-145 kPa (abs) and transferring the obtained residual mixture to the second reactor; (c) polymerizing ethylene and optionally C.sub.4 to C.sub.12 α-olefin comonomer in the second reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and in the presence of hydrogen in an amount obtained in step (b) to obtain a first high molecular weight polyethylene or a first ultra high molecular weight polyethylene in the form of a homopolymer or a copolymer and transferring a resultant mixture to the third reactor; and (d) polymerizing ethylene, and optionally α-olefin comonomer in the third reactor in the presence of a catalyst system, selected from Ziegler-Natta catalyst or metallocene, and hydrogen, wherein the amount of hydrogen in the third reactor is in a range of 1-70% by mol, preferably 1-60% by mol with respect to the total gas present in the vapor phase in the third reactor or optionally substantial absence of hydrogen to obtain a second high molecular weight polyethylene or a second ultra high molecular weight polyethylene homopolymer or copolymer; and a multimodal polyethylene composition obtainable this way.