Abstract: This invention relates to high density polyethylene blown films having good barrier properties and improved processing characteristics. The method incorporates the use of peroxide which results in improved bubble stability without sacrifice in barrier properties. The polyethylenes have a density greater than about 0.950 g/cc, are relatively narrow in molecular weight distribution MWD (in the range of from about 2.0 to about 6.5), and are of medium molecular weight. In an embodiment, the films also have a rheological breadth parameter, a, that has been reduced by at least about 5%, but not more than 45%, by addition of a peroxide to the polyethylene. The addition of peroxide improves processability without sacrificing strength and barrier properties such as oxygen transmission rate.

Abstract: Disclosed is a bimodal Ziegler-Natta catalyzed polyethylene, having a density of from 0.930 g/cc to 0.960 g/cc, and a molecular weight distribution of from 10 to 25, wherein an article formed therefrom has a PENT of at least 1500. Also disclosed is a method of preparing a tubular article including obtaining a bimodal polyethylene having a density of from 0.930 g/cc to 0.960 g/cc and a molecular weight distribution of from 10 to 25, and processing the polyethylene under conditions where a specific energy input (SEI) is less than 300 kW.h/ton, and wherein the article has a PENT of at least 1500. Further disclosed is a method for controlling the degradation of polyethylene including polymerizing ethylene monomer, recovering polyethylene, extruding the polyethylene, and controlling the degradation of polyethylene by measuring the SEI to the extruder and adjusting throughput and/or gear suction pressure keep SEI less than 300 kW.h/ton, and forming an article.

Abstract: Polyethylene modified by using radical initiators such as oxygen and peroxides sometimes has a yellow color which may be reduced or eliminated by incorporating additives such as polyethylene glycol, and/or neutralizing species such as alkali metal stearates, particularly calcium stearate, and zinc oxide.

Abstract: The rheology of polyethylene resin may be controlled by measuring the specific energy input (SEI) to the extruder and then adjusting a process parameter in response to a change in the SEI and/or by introducing both a free radical initiator and an alkali earth metal stearate into the polymerization. Indeed, the process parameter changed in response to the SEI measurement may be adjusting the proportion of free radical initiator, adjusting the proportion of alkali earth metal stearate, or both. The free radical initiator may be a peroxide, and the alkali earth metal stearate may be calcium stearate.

Abstract: Improving polyethylene film properties may be accomplished by measuring the specific energy input (SEI) to the extruder and then adjusting a process parameter in response to a change in the SEI and/or by introducing both a free radical initiator and an alkali earth metal stearate into the polymerization. Alternatively or in addition thereto, selecting the optimum free radical initiator for a particular polyethylene resin polymerized in the presence of a selected catalyst between two resin properties may be accomplished by examining the ratio of: % ? ? ? variation ? ? ? in ? ? ? a ? ? ? first ? ? ? property % ? ? ? variation ? ? ? in ? ? ? a ? ? ? second ? ? ? property of polyethylene resins individually made with each free radical initiator under consideration. The free radical initiator may be oxygen, peroxides, peroxyketals, peroxyesters, and/or dialkyl peroxides.

Abstract: Commonly used triethyl aluminum and tri-isobutyl aluminum cocatalysts can be replaced in olefin polymerizations with a cocatalyst conforming to the formula AlRz(Xz)nLzm wherein Rz is a linear or branched organic moiety having at least 5 carbons and Xz is a linear or branched organic moiety having at least 5 carbons or heteroatom substituted organic moiety or a heterocyclic moiety having at least 4 atoms and can be anionic (n=2) or dianionic (n=1). Xz can also be hydrogen. The aluminum complex may also be in the form of an adduct complex where Lz is a Lewis base and m=1-3. The general formula is subject to the proviso that when n=2, each Xz may be the same or different and that both Xz moieties may not be hydrogen. Use of the invention enables production of a polyolefin film, such as polyethylene film, exhibiting improved bubble stability and other desirable properties.

Abstract: Commonly used triethyl aluminum and tri-isobutyl aluminum cocatalysts may be replaced in olefin polymerizations with a cocatalyst conforming to the formula AlRz(Xz)nLzm wherein Rz is a linear or branched organic moiety having at least 5 carbons and Xz is a linear or branched organic moiety having at least 5 carbons or heteroatom substituted organic moiety or a heterocyclic moiety having at least 4 atoms and may be anionic (n=2) or dianionic (n=1). Xz may also be hydrogen. The general formula is subject to the proviso that when n=2, each Xz may be the same or different and that both Xz moieties may not be hydrogen. The aluminum complex may also be in the form of an adduct complex where Lz is a Lewis base and m=1-3. Use of the invention enables production of a polyolefin pipe, such as polyethylene pipe, exhibiting improved processing, crack resistance and other desirable properties.

Abstract: It has been discovered that certain compounds serve as particle size regulators when employed together with peroxide initiators for the polymerization of vinylaromatic monomers in the presence of diene polymers. Suitable compounds that can control particle size include, but are not necessarily limited to, cobalt naphthenate, zinc naphthenate, iron octoate, calcium octoate, zinc octoate, zinc neodecanoate, potassium octoate, copper naphthenate, calcium versalate, and the like. Use of these metal carboxylates when vinylaromatic monomers are polymerized in the presence of polybutadienes and peroxide initiators results in reduced polybutadiene particles. Grafting and morphology characteristics may also be improved.

Abstract: Disclosed are novel non-linear vinyl polymers comprised of a multifunctional peroxide, and a cross-linking agent and/or a chain transfer agent, and methods of making such polymers having: at least 0.03 branches/1000 backbone carbons; linear portions with a molecular weight (Mw) of 350,000 or less; 0.2 to 3.0 branches/molecule; or, a Mz/Mw of from 1.7 to 5.7. Methods of quantifying branching are disclosed using a linear reference having 0.0 to 0.06 branches/1000 backbone carbons along with SEC techniques and measurements of molecular weight, molecular size, and concentration. Also discovered is a vinyl polymer resin comprised of from 0.1 to 50 weight percent of non-linear polymers having at least 0.06 branches/1000 backbone carbons, where branching is measured using a heat polymerized polystyrene having from 0.0 to 0.06 branches/1000 backbone carbons as a linear reference.

Abstract: It has been discovered that improved polystyrene products may be obtained by polymerizing styrene in the presence of at least one multifunctional initiator, at least one chain transfer agent, and at least one cross-linking agent. The presence of the multifunctional initiator tends to cause more branched structures in the polystyrene. A mathematical model that helps optimize the levels of these additives for given molecular weights, melt flow indices (MFIs) and zero shear viscosities (?0) has also been discovered.

Abstract: It has been discovered that the melt instability of styrenic polymers, particularly high impact polystyrene (HIPS) can be reduced or eliminated by the blending therewith of a relatively high melt flow index (MFI) material, such as polystyrene homopolymer. Draw resonance of the melt blend can also be reduced by this method, thereby improving melt processing of these materials. A method to measure melt instability of drawn materials is also discussed.

Abstract: It has been discovered that certain compounds serve as particle size regulators when employed together with peroxide initiators for the polymerization of vinylaromatic monomers in the presence of diene polymers. Suitable compounds that can control particle size include, but are not necessarily limited to, cobalt naphthenate, zinc naphthenate, iron octoate, calcium octoate, zinc octoate, zinc neodecanoate, potassium octoate, copper naphthenate, calcium versalate, and the like. Use of these metal carboxylates when vinylaromatic monomers are polymerized in the presence of polybutadienes and peroxide initiators results in reduced polybutadiene particles. Grafting and morphology characteristics may also be improved.

Abstract: It has been discovered that improved polystyrene products may be obtained by polymerizing styrene in the presence of at least one multifunctional initiator, at least one chain transfer agent, and at least one cross-linking agent. The presence of the multifunctional initiator tends to cause more branched structures in the polystyrene. A mathematical model that helps optimize the levels of these additives for given molecular weights, melt flow indices (MFIs) and zero shear viscosities (&eegr;0) has also been discovered.

Abstract: It has been discovered that certain compounds serve as polymerization accelerators when employed together with peroxide initiators for the polymerization of vinylaromatic monomers. Suitable accelerators that increase the rate of decomposition of the peroxide initiator include, but are not necessarily limited to, hydroperoxides and/or metallic salts. Representative examples of suitable hydroperoxide accelerators include t-butyl hydroperoxide (TBH), cumyl hydroperoxide, and p-isopropyl cumyl hydroperoxide, whereas suitable metallic salt accelerators include cobalt naphthenate and cobalt acetoacetonate. Use of these accelerators when vinylaromatic monomers are polymerized in the presence of polybutadienes and peroxide initiators results in an increase in grafting as compared with similar copolymers made without the accelerator.

Abstract: A fiber product drawn from an isotactic propylene copolymer of a C2, C4, C5, C6, C7 or C8 &agr;-olefin monomer produced in the presence of a metallocene catalyst characterized by a bridged chiral and stereorigid cyclopentadienyl or substituted cyclopentadienyl ligand structure of a transitional metal selected from group 4b, 5b, or 6b metals of the Periodic Table of Elements, the copolymer having a MFR less than 35, suitably about 30 or less. The copolymer is heated to a molten state and extruded to form a fiber preform. The preform is subjected to spinning at a spinning speed of at least 300 meters per minutes and subsequent drawing at a speed of up to about 1500 meters per minute to provide a draw ratio of at least 1.5 up to 5:1 to produce a continuous fiber having high tenacity of about 3.5 grams per denier and greater and good hand.

Abstract: The present invention provides a method for preparing an asphalt and thermoplastic elastomer composition. The process comprises preparing a crosslinking elastomer concentrate that is added to a heated asphalt cut in a stirred tank and then aged to improve SHRP high temperature grading. The crosslinking elastomer concentrate is prepared by adding thermoplastic elastomer and crosslinking agents to a suitable carrier oil, preferably an aromatic oil such as Hydrolene H series. This concentrate is maintained at a temperature that promotes association between the crosslinking agents and the elastomer for a time sufficient for association to substantially complete. In one embodiment, the associating time is in excess of 2 hours up to 24 hours. The asphalt is heated to a temperature sufficient to allow the stirring of the asphalt in the tank. The crosslinking thermoplastic elastomer concentrate is added to the asphalt while continuing to stir the asphalt.