A method may include polymerizing ethylene in a tubular reactor, where the polymerization is substantially free of a chain transfer agent. A method may include polymerizing ethylene in a tubular reactor, the ethylene having a specific delivery pressure and the polymerization having one or more specific peak temperatures. The molecular weight of the resulting polyethylene may be controlled by the selection of the delivery pressure and the one or more peak temperatures.

A method may include polymerizing ethylene in a tubular reactor, where the polymerization is substantially free of a chain transfer agent. A method may include polymerizing ethylene in a tubular reactor, the ethylene having a specific delivery pressure and the polymerization having one or more specific peak temperatures. The molecular weight of the resulting polyethylene may be controlled by the selection of the delivery pressure and the one or more peak temperatures.

The present invention relates to a polyvinyl alcohol-based resin, wherein when the polyvinyl alcohol-based resin is made into a 0.1 wt % aqueous solution, an absorbance (X) at a wavelength of 320 nm in an ultraviolet absorption spectrum thereof is 0.3 or more, and a ratio (Y/X) of an absorbance (Y) at a wavelength of 380 nm to the absorbance (X) at a wavelength of 320 nm is 0.09 or more.

The present invention relates to a process for producing ultrahigh molecular weight polymer in powder form which is highly efficient drag reducing polymer. The process consists of polymerizing using titanium halide-based catalyst, co-catalyst, optionally a solvent, and monomer to a polymerization reactor, having stirring device and inlet charging and discharge outlet. The resulting ultrahigh molecular weight drag reducing polymers is free flowing, having intrinsic viscosity >10 dL/g. The process reduces polymerization time, temperature, and achieves high conversion, i.e., >90%.

The present invention relates to a process for producing ultrahigh molecular weight polymer in powder form which is highly efficient drag reducing polymer. The process consists of polymerizing using titanium halide-based catalyst, co-catalyst, optionally a solvent, and monomer to a polymerization reactor, having stirring device and inlet charging and discharge outlet. The resulting ultrahigh molecular weight drag reducing polymers is free flowing, having intrinsic viscosity >10 dL/g. The process reduces polymerization time, temperature, and achieves high conversion, i.e., >90%.

The invention relates to a process for the preparation of low density polyethylene (LDPE) wherein the polymerisation takes place in a tubular reactor at peak temperatures ranging from 180° C. to 350° C. and at pressures ranging from 150 to 350 MPa and wherein the total effective length of the polymerisation reactor divided by the number of reaction zones is in the range from 230 to 350 m.

The invention relates to a process for the preparation of low density polyethylene (LDPE) wherein the polymerisation takes place in a tubular reactor at peak temperatures ranging from 180° C. to 350° C. and at pressures ranging from 150 to 350 MPa and wherein the total effective length of the polymerisation reactor divided by the number of reaction zones is in the range from 230 to 350 m.

The present invention relates to an ethylene copolymer obtained by radical polymerisation through a high-pressure process comprising (i) ≥78.0 and ≤99.99 mole % of recurring units derived from ethylene; (it) ≥0.01 and ≤22.0 mole % of recurring units derived from comonomer A according to Formula (I), wherein R1 is composed of a saturated aliphatic moiety comprising 5-40 carbon atoms or R1 is composed of a saturated aliphatic moiety and consists of hydrogen atoms and 5-40 carbon atoms; R2 is selected from —H or —CH.sub.3; R3 is selected from —O—, —(CO)—(NH)— or —(CO)—O—; n=0 or 1 The ethylene copolymers have a reduced peak melting temperature and reduced enthalpy of fusion, indicating that these ethylene copolymers have a reduced degree of crystallinity and improved clarity, combined with a desired melt mass-flow rate. ##STR00001##

The present invention relates to an ethylene copolymer obtained by radical polymerisation through a high-pressure process comprising (i) ≥78.0 and ≤99.99 mole % of recurring units derived from ethylene; (it) ≥0.01 and ≤22.0 mole % of recurring units derived from comonomer A according to Formula (I), wherein R1 is composed of a saturated aliphatic moiety comprising 5-40 carbon atoms or R1 is composed of a saturated aliphatic moiety and consists of hydrogen atoms and 5-40 carbon atoms; R2 is selected from —H or —CH.sub.3; R3 is selected from —O—, —(CO)—(NH)— or —(CO)—O—; n=0 or 1 The ethylene copolymers have a reduced peak melting temperature and reduced enthalpy of fusion, indicating that these ethylene copolymers have a reduced degree of crystallinity and improved clarity, combined with a desired melt mass-flow rate. ##STR00001##

The present invention relates to a propylene-butene copolymer resin composition used for non-woven fabric, a method of preparing the same, and spunbond non-woven fabric manufactured using the composition, and particularly, by optimizing a content of 1-buttene in a metallocene polypropylene resin composition to 0.5 to 5.0 wt %, while simultaneously optimizing both of a melt index and a residual stress ratio of the resin composition, has a merit of having a reduced modulus together with a high conversion rate to manufacture non-woven fabric which is softer than existing products while maintaining high strength.