摘要:
Ethylene and allyl- or vinylsilanes are efficiently copolymerized by certain late transition metal complexes containing selected bidentate or tridentate ligands. The resulting novel polymers may be crosslinked by moisture when vinylsilane contains groups bound to silicon which are hydrolyzable. The polymers are useful for wire coating, crosslinked foams, pipes, and other uses.
摘要:
The present invention relates generally to polyolefin production and to reducing volatile organic content (VOC) associated with the polyolefin. Techniques include the construction and implementation of a purge column model to calculate or estimate the VOC content in the polyolefin exiting the purge column. The techniques facilitate the design and operation of the polyolefin manufacturing process.
摘要:
There is provided a process for producing a prepolymerization catalyst for polymerization of an olefin, said process comprising the steps of feeding, to a polymerization reactor, an olefin and a solid catalyst component in which a catalyst component for polymerization of the olefin is carried on a fine particle support, and prepolymerizing the olefin in the presence of the solid catalyst component in the polymerization reactor, to thereby obtain the prepolymerization catalyst in which the olefin is prepolymerized on the solid catalyst component, characterized in that said solid catalyst component is pressure-fed to the polymerization reactor from a catalyst feeder connected to the polymerization reactor, and in that the inner pressure of the catalyst feeder at the start of the pressure-feeding is set at (Pr+0.0001) to (Pr+1) (MPa in unit) (in which Pr represents the inner pressure of the polymerization reactor (MPa in unit) at the start of the pressure-feeding).
摘要:
Provided are apparatus and methods relating to the finishing line of a continuous solution polymerization plant. In one aspect, an apparatus includes a pelletizer having cooling liquid, e.g., water or aqueous solution, into which is added a pelletization aid. In another aspect, the apparatus comprises means to remove residual polymer particles from the pelletizer cooling liquid. In a further aspect, the apparatus comprises conduits of at least 50 m in length for carrying propellant cooling liquid from the pelletizer to a drying apparatus. The residence time of the pellets in the cooling liquid may be 10 seconds or more. In a further aspect, a drying apparatus is provided for the pellets which comprises first and second drying zones. In a further aspect, a pneumatic conveyor is provided for carrying pellets to a packaging apparatus. In a further aspect, a packaging apparatus is provided comprising a blender silo.
摘要:
The invention relates to thermally expandable thermoplastic microspheres comprising a polymer shell made from ethylenically unsaturated monomers encapsulating a propellant, said ethylenically unsaturated monomers comprising from 40 to 70 wt % of acrylonitrile, from 5 to 40 wt % of methacrylonitrile, from 10 to 50 wt % of monomers selected from the group consisting of esters of acrylic acid, esters of methacrylic acid and mixtures thereof, and said propellant comprising at least one of methane, ethane, propane, isobutane, n-butane and neo-pentane. The invention further relates to the production and use of the microspheres.
摘要:
A method for transitioning from a first to a second catalyst system for the olefin polymerization reaction in one reactor, wherein the first catalyst system is incompatible with the second catalyst system, is described. The method comprises the steps of a) discontinuing a first olefin polymerization reaction performed in the presence of the first catalyst system; and b) performing a second olefin polymerization reaction in the presence of the second catalyst system comprising catalyst components (A) and (B) producing, respectively, a first and a second polyolefin fraction, wherein the Mw of the first polyolefin fraction is less than the Mw of the second polyolefin fraction and the initial activity of catalyst component (A) exceeds the initial activity of catalyst component (B). Thanks to this method, there is no need to empty the reactor after the first olefin polymerization reaction, and the transitioning time needed to attain the desired quality of the polyolefin obtained in the second olefin polymerization reaction is sufficiently short to permit a quick and reliable change of production.
摘要:
This invention relates to blends of linear low density polyethylene copolymers with other linear low density polyethylenes or very low density, low density, medium density, high density, and differentiated polyethylenes. The invention also includes articles produced from the linear low density polyethylene and polyethylene blends described.
摘要:
A method according to one embodiment includes operating a reactor or providing a reactor after operation, wherein the reactor includes a bottom section, a bed section above the bottom section, a distributor plate between the bottom section and the bed section, an expanded section above the bed section, and an upper section above the bed section, wherein the bed section has a height H measured from the distributor plate to the expanded section; measuring a concentration of particulates in the upper section of the reactor to obtain a first determined level of particulates in the upper section; and discharging at least some of the particulates from the reactor at an upper discharge point located above 0.55H as measured vertically from the distributor plate based on the first determined level. Additional systems and methods are also provided.
摘要:
Embodiments of the present invention relate to operating a gas-phase reactor at or near maximum production rates and to measuring and controlling polymer stickiness in a gas phase reactor polymerization. In particular, embodiments relate to monitoring acoustic emissions in a reactor during gas phase polymerization to determine the onset of reactor stickiness and possibly discontinuity events such as chunking and sheeting resulting from that stickiness. Embodiments also relate to monitoring acoustic emissions to determine the need for effective control of parameters that minimize reactor stickiness and thereby preventing discontinuity events. The emissions are processed by arithmetic averaging.
摘要:
Artificial turf stock materials useful for artificial turf stock backfixing, including: a hotmelt made of: a) from 5% to 100% by weight of at least one amorphous poly-α-olefin, b) from 0% to 100% by weight of at least one modified amorphous poly-α-olefin, c) from 0% to 40% by weight of at least one resin, d) from 5% to 15% by weight of at least one modified crystalline polypropylene, e) from 0% to 20% by weight of at least one crystalline polyolefin, f) from 0% to 80% by weight of fillers or pigments, g) from 0% to 20% by weight of at least one flame retardant, and h) from 0% to 20% by weight of at least one wax, where ribbon yarn of polyethylene, polypropene, polyester, polymide, or an interpolymer is bound together with the hotmelt in an artificial turf stock material.