A method for producing gradient copolymers can include polymerizing a reaction mixture comprising a monomer and a comonomer in the presence of a metallocene catalyst in a loop reactor, wherein in the loop reactor a gradient monomer weight percent in the reaction mixture is about 3 wt % to about 50 wt %, thereby forming a gradient copolymer.

The present disclosure provides novel unbridged group 4 indacenyl-containing metallocene compounds. The catalyst system may be used for olefin polymerization processes.

The present disclosure provides novel unbridged group 4 indacenyl-containing metallocene compounds. The catalyst system may be used for olefin polymerization processes.

The present disclosure provides a catalyst system having a Group 15 catalyst compound and borate or aluminate activators comprising cations having alkyl groups and methods for polymerizing olefins using such catalyst systems. In still another embodiment, the present disclosure provides a polymerization process comprising a) contacting one or more olefin monomers with a catalyst system comprising: i) an activator as described herein, ii) a catalyst compound as described herein, and iii) optional support.

The present disclosure provides a catalyst system having a Group 15 catalyst compound and borate or aluminate activators comprising cations having alkyl groups and methods for polymerizing olefins using such catalyst systems. In still another embodiment, the present disclosure provides a polymerization process comprising a) contacting one or more olefin monomers with a catalyst system comprising: i) an activator as described herein, ii) a catalyst compound as described herein, and iii) optional support.

To provide hollow particles excellent in performance stability in a high-humidity environment and low in relative permittivity. Hollow particles which comprise a shell containing a resin and a hollow portion surrounded by the shell, wherein the shell contains, as the resin, a polymer in which from 70 parts by mass to 100 parts by mass of a crosslinkable monomer unit is contained in 100 parts by mass of all monomer units; wherein a void ratio is 60% or more; wherein a content of a surfactant present on a surface of the hollow particles is 200 ppm or less; and wherein a relative permittivity at a frequency of 1 MHz is 1.6 or less.

To provide hollow particles excellent in performance stability in a high-humidity environment and low in relative permittivity. Hollow particles which comprise a shell containing a resin and a hollow portion surrounded by the shell, wherein the shell contains, as the resin, a polymer in which from 70 parts by mass to 100 parts by mass of a crosslinkable monomer unit is contained in 100 parts by mass of all monomer units; wherein a void ratio is 60% or more; wherein a content of a surfactant present on a surface of the hollow particles is 200 ppm or less; and wherein a relative permittivity at a frequency of 1 MHz is 1.6 or less.

The present invention relates to a high-density ethylene-based polymer comprising: an ethylene homopolymer; or a copolymer of ethylene and at least one comonomer selected from the group consisting of -olefins, cyclic olefins and linear, branched and cyclic dienes. According to the present invention, the high-density ethylene-based polymer has a wide molecular weight distribution and excellent comonomer distribution characteristics, has excellent melt flowability due to a long chain branched structure, and has excellent mechanical characteristics since the comonomer distribution is concentrated in a high-molecular-weight body. The high-density ethylene polymer of the present invention has excellent molding processability during processing such as extrusion, compression, injection and rotational molding by having excellent mechanical characteristics and melt flowability.

The present invention relates to a high-density ethylene-based polymer comprising: an ethylene homopolymer; or a copolymer of ethylene and at least one comonomer selected from the group consisting of -olefins, cyclic olefins and linear, branched and cyclic dienes. According to the present invention, the high-density ethylene-based polymer has a wide molecular weight distribution and excellent comonomer distribution characteristics, has excellent melt flowability due to a long chain branched structure, and has excellent mechanical characteristics since the comonomer distribution is concentrated in a high-molecular-weight body. The high-density ethylene polymer of the present invention has excellent molding processability during processing such as extrusion, compression, injection and rotational molding by having excellent mechanical characteristics and melt flowability.

Embodiments of this disclosure include processes of polymerizing olefins, the process comprising contacting ethylene and a (C.sub.3-C.sub.40)alpha-olefin comonomer in the presence of a catalyst system, the catalyst system comprising a Group IV metal-ligand complex and a metallic activator ionic complex, the metallic activator ionic complex comprising an anion and a countercation, the anion having a structure according to formula (I):