摘要:
A polyolefin composition is provided which consists essentially of isotactic polypropylene and, optionally, repeating units of one or more comonomers, wherein the total comonomer repeating unit content of the polyolefin composition is from 0 to 20 mole percent, and further, wherein the weight average branching index g′ for the lower molecular weight region of the polyolefin composition is less than 0.93. Additionally, a process is provided for producing a polyolefin composition comprising: a) contacting, in solution, at a temperature from about 90° C. to about 120° C., propylene monomers with a catalyst composition comprising a first chiral, stereorigid transition metal catalyst compound capable of producing isotactic polypropylene; b) copolymerizing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor under suitable polypropylene polymerization conditions using a second chiral, stereorigid transition metal catalyst capable of producing isotactic polypropylene; and c) recovering a branched olefin polymer.
摘要:
The invention is a polyethylene composition having a polydispersity index of less than or equal to 3, an average branching index (g') as measured by GPC/Vis.gtoreq.0.9, and a melt strength (MS) (centiNewton, 190.degree. C.) that satisfies the relationship: ##EQU1## In a preferred embodiment these polyethylene compositions comprise A) branched polyethylene copolymers prepared by insertion polymerization of ethylene, ethylene-containing macromers, and optionally, additional copolymerizable monomers, and B) essentially linear ethylene copolymers. Improved melt strength without sacrificing the benefits of narrow polydispersity index are exhibited by the invention compositions.
摘要:
Systems and methods for monitoring a particle/fluid mixture are provided. The method can include flowing a mixture comprising charged particles and a fluid past a particle accumulation probe. The method can also include measuring electrical signals detected by the probe as some charged particles pass the probe without contacting the probe while other charged particles contact the probe. The measured electrical signals can be manipulated to provide an output. The method can also include determining from the output if the charged particles contacting the probe have, on average, a different charge than the charged particles that pass the probe without contacting the probe.
摘要:
A polyolefin product is provided which comprises a branched olefin copolymer having an syndiotactic polypropylene backbone, polyethylene branches and, optionally, one or more comonomers. The total comonomer content of the branched olefin copolymer is from 0 to 20 mole percent. Also, the mass ratio of the syndiotactic polypropylene to the polyethylene ranges from 99.9:0.1 to 50:50. Additionally, a process is provided for preparing a branched olefin copolymer which comprises: a) copolymerizing ethylene, optionally with one or more copolymerizable monomers, in a polymerization reaction under conditions sufficient to form copolymer having greater than 40% chain end-group unsaturation; b) copolymerizing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor under suitable polypropylene polymerization conditions using a chiral, stereorigid transition metal catalyst capable of producing syndiotactic polypropylene; and c) recovering a branched olefin copolymer.
摘要翻译:提供了一种聚烯烃产品,其包含具有间同立构聚丙烯主链,聚乙烯分支和任选的一种或多种共聚单体的支链烯烃共聚物。 支链烯烃共聚物的总共聚单体含量为0〜20摩尔%。 另外,间同立构聚丙烯与聚乙烯的质量比为99.9:0.1〜50:50。 另外,提供了一种制备支链烯烃共聚物的方法,其包括:a)在足以形成具有大于40%的链端基不饱和度的共聚物的条件下,在聚合反应中将乙烯任选地与一种或多种可共聚单体共聚; b )使用可产生间同立构聚丙烯的手性立体刚性过渡金属催化剂,在合适的聚丙烯聚合条件下,在聚合反应器中将a)的产物与丙烯和任选的一种或多种可共聚单体共聚; 和c)回收支链烯烃共聚物。
摘要:
Branched ethylene-propylene compositions which have improved melt strength and shear thinning are provided. The weight average branching index g′ for the higher molecular weight region of the ethylene-propylene composition is less than 0.95. Additionally, a novel process is provided for efficiently producing a branched ethylene-propylene composition comprising: a) contacting propylene monomers and ethylene monomers in a reactor with an inert hydrocarbon solvent or diluent and a catalyst composition comprising one or more single site catalyst compounds capable of producing an ethylene-propylene polymer at a temperature from about 50° C. to about 180° C., wherein the ratio in the reactor of the propylene and ethylene monomers to the inert hydrocarbon solvent or diluent is less than 2.0, and further, wherein the propylene and ethylene monomers and the inert hydrocarbon solvent or diluent comprise no more than 90 percent of the total contents of the reactor; and b) recovering a branched ethylene-propylene composition, wherein the weight average branching index g′ for the higher molecular weight region of the ethylene-propylene composition is less than 0.95.
摘要:
A thermoplastic elastomer is provided comprising a branched olefin polymer having crystalline sidechains and an amorphous backbone wherein at least 90 mole percent of the sidechains are isotactic or syndiotactic polypropylene and at least 80 mole percent of the backbone is atactic polypropylene. Additionally, a process is provided for producing a thermoplastic elastomer composition comprising: a) contacting, in solution, at a temperature from about 90° C. to about 120° C., propylene monomers with a catalyst composition comprising a chiral, stereorigid transition metal catalyst compound capable of producing isotactic or syndiotactic polypropylene; b) copolymerizing the product of a) with propylene and, optionally, one or more copolymerizable monomers, in a polymerization reactor using an achiral transition metal catalyst capable of producing atactic polypropylene; and c) recovering a branched olefin polymer.
摘要:
Stereospecific polypropylene macromers having a high percentage of vinyl terminal bonds and a method for preparing them are provided. The stereospecific polypropylene macromers have number average molecular weights (M.sub.n) of about 2,000 Daltons to about 50,000 Daltons, and the total number of vinyl groups per 1000 carbon atoms is greater than or equal to 7000.div.M.sub.n. The method for preparing the macromers involves:a) contacting, in solution, at a temperature from about 90.degree. C. to about 120.degree. C., two or more propylene monomers with a catalyst composition comprising a chiral, stereorigid transition metal catalyst compound; andb) recovering stereospecific polypropylene chains having number average molecular weights of about 2,000 Daltons to about 50,000 Daltons and significant vinyl unsaturation.
摘要:
Processes for the polymerization of olefins with extracted metal carboxylate salts are provided. The polymerization processes have increased productivity and/or increased resin bulk density.
摘要:
Described herein are methods for monitoring and restoring electrical properties of polymerization reactor wall films. The method may comprise using a reactor wall monitor to monitor and determine an electrical property, such as the bed voltage or breakdown voltage, of the wall film. The method may further comprise adding continuity additive to the reactor and/or adjusting the feed rate of continuity additive being added to the reactor in response to the measured electrical property.
摘要:
Described herein are methods for monitoring and restoring electrical properties of polymerization reactor wall films. The method may comprise using a reactor wall monitor to monitor and determine an electrical property, such as the bed voltage or breakdown voltage, of the wall film The method may further comprise adding continuity additive to the reactor and/or adjusting the feed rate of continuity additive being added to the reactor in response to the measured electrical property.