Linear, very low density polyethylene polymerization process and products thereof
AssigneePhillips Petroleum Company
InventorsMax P. McDaniel, Elizabeth A. Benham
Life of this patent
Estimating the term…
Abstract
A copolymer of ethylene and a higher alpha-olefin, preferably 1-butane and/or 1-hexane, can be produced using an activated and subsequently carbon monoxide reduced chromium containing catalyst system and an alkylaluminum or alkylboron cocatalyst. The polymerization process must be carefully controlled to produce a copolymer resin that can be made into a tough product, with an increased melt index and a broad molecular weight distribution.
Claims16
A copolymer composition of ethylene and at least one higher alpha-olefin selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene and mixtures thereof comprising:
- a) from about 12 to about 40 weight percent higher alpha-olefin, based on the total weight of the copolymer, in said copolymer;
- and
- b) from about 100 to about 180 short chain branches per 10,000 backbone carbons of said copolymer;
- and
- wherein said copolymer has a density within a range of about 0.89 to about 0.915 g/cc, a melt index (MI) within a range of about 0.05 to about 0.35 g/10 minutes, a high load melt index (HLMI) within a range of about 5 to about 50 g/10 minutes, a HLMI/MI ratio within a range of about 100 to about 300, and a Mw/Mn ratio within a range of about 12 to about 35.
A copolymer composition produced according to a slurry polymerization process comprising contacting in a reaction zone under polymerization conditions, at a reaction zone temperature in a range of about 60.degree. to about 77.degree. C.:
- a) a diluent of isobutane;
- b) ethylene monomer;
- c) a comonomer of 1-hexene, present in an amount within the range of about 30 to about 60 weight percent, based on the amount of ethylene;
- d) triethyl borane, present in an amount within the range of about 2 to about 20 ppm, based on the mass of the diluent;
- and
- e) a catalyst system comprising chromium supported on a silica-titania support, wherein said support comprises from about 2 to about 20 weight percent titanium, based on the weight of the support, and wherein said catalyst system has been activated in an oxygen-containing ambient at a temperature within the range of about 300.degree. to about 1000.degree. C. and subsequently reduced in the presence of carbon monoxide at a temperature within the range of about 300.degree. to about 500.degree. C.;
- and recovering a polymer.
A copolymer composition wherein said polymer has:
- a) a density in the range of from about 0.89 to about 0.915 g/cc;
- b) a melt index within a range of about 0.05 to about 0.35 g/10 minutes;
- c) a high load melt index (HLMI) within a range of about 5 to about 50 g/10 minutes;
- d) a HLMI/MI ratio within a range of about 100 to about 300;
- and
- e) a Mw/Mn ratio within a range of about 12 to about 35.
- wherein said composition is produced according to a slurry polymerization process comprising contacting in a reaction zone under polymerization conditions, at a reaction zone temperature in the range of from about 60.degree. to about 77.degree. C.:
- f) a diluent selected from the group consisting of paraffins, cycloparaffins, aromatic hydrocarbons, and mixtures thereof;
- g) ethylene monomer;
- h) at least one comonomer selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, and mixtures thereof, present in an amount in the range of from about 30 to about 60 weight percent, based on the amount of ethylene;
- and
- i) a trialkyl boron compound, present in an amount in the range of from about 2 to about 20 ppm, based on the mass of the diluent;
- and
- j) a catalyst system comprising chromium supported on a silica-titania support, wherein said support comprises from about 2 to about 20 weight percent titanium, based on the weight of the support, and wherein said catalyst system has been activated in an oxygen-containing ambient and subsequently reduced in the presence of carbon monoxide in an inert ambient.
Dependencies are inferred from the claim text.