Dow Global Technolgoies LLC

Cornelis J Hosman

Otto J Berbee

Werner Zschoch

Mehmet Demirors

Jian Jim Wang

Teresa Plumley Karjala

Sarat Munjal

Lonnie G Hazlitt

Cornelis F J Den Doelder

Stefan Hinrichs

Christopher R Eddy

Wallace W Yau

Jian Wang

Wallace Yau

Otto Berbee

A high pressure polymerization process to form an ethylene-based polymer comprises the steps of:

Polymerization process to make low density polyethylene

A high pressure polymerization process to form an ethylene-based polymer comprises the steps of: A. Injecting a first feed comprising a chain transfer agent system (CTA system) and ethylene into a first autoclave reactor zone operating at polymerization conditions to produce a first zone reaction product, the CTA system of the first reactor zone having a transfer activity Z1; and B. (1) Transferring at least part of the first zone reaction product to a second reactor zone selected from a second autoclave reactor zone or a tubular reactor zone and operating at polymerization conditions, and, optionally, (2) freshly injecting, a second feed into the second reactor zone to produce a second zone reaction product, with the proviso that at least one of the first reactor zone product and the freshly injected feed comprises a CTA system with a transfer activity of Z2; and with the proviso that the ratio of Z1:Z2 is greater than 1.

The invention provides a high pressure polymerization process to form an ethylene-based polymer, the process comprising at least the following steps: feeding ethylene to a first reaction zone and to one or more subsequent reaction zones, and wherein for each subsequent reaction zone that receives fresh ethylene, the ratio, Rn (n=reaction zone number, n&#x3e;1), of 'mass fraction of fresh ethylene fed to the first reaction zone (RZ1)' to 'mass fraction of fresh ethylene fed to the nth reaction zone (RZn)' is (Rn=RZ1/RZn) greater than 1, or is from 0 to 0.30, and wherein the &#x201c;total amount of ethylene fed to the polymerization process&#x201d; derives from at least one fresh ethylene stream and at least one recycled ethylene stream, and wherein the at least one recycled ethylene stream comprises at least one chain transfer agent and/or comprises at greater than, or equal to, 1 weight %, based on total amount of components in recycled ethylene stream, of one or more non-ethylene components and/or CTA(s); and wherein the inlet feed to each reaction zone comprises less than 5 weight ppm oxygen based on the total weight of mass flows fed to the reaction zone. The invention also provides a high pressure polymerization process to form an ethylene-based polymer, the process comprising at least the following steps: feeding ethylene to a first reaction zone and to one or more subsequent reaction zones, and wherein 100 weight percent of the total amount of fresh ethylene fed to the polymerization process is fed to the first reaction zone, and wherein the &#x201c;total amount of ethylene fed to the polymerization process&#x201d; derives from at least one fresh ethylene stream and at least one recycled ethylene stream, and wherein the at least one recycled ethylene stream comprises at least one chain transfer agent and/or comprises at greater than, or equal to, 1 weight %, based on total amount of components in recycled ethylene stream, of one or more non-ethylene components and/or CTA(s); and wherein the inlet stream to each reaction zone comprises less than, or equal to, 5 weight ppm oxygen, based on the total weight of mass flows fed to the reaction zone.

Polymerization processes with fresh ethylene distributions for preparation of low density ethylene-based polymers

Disclosed is an ethylene-based polymer with a density from about 0.90 to about 0.94 in grams per cubic centimeter, with a molecular weight distribution (M/M) from about 2 to about 30, a melt index (I) from about 0.1 to about 50 grams per 10 minutes, and further comprising sulfur from about 5 to about 4000 parts per million. The amount of sulfur is also determined based upon the total weight of the ethylene-based polymer. Also disclosed is process for making an ethylene-based polymer which includes the steps of splitting a process fluid for delivery into a tubular reactor; feeding an upstream process feed stream into a first reaction zone and at least one downstream process feed stream into at least one other reaction zone, where the process fluid has an average velocity of at least 10 meters per second; and initiating a free-radical polymerization reaction.

High pressure low density polyethylene resins with improved optical properties produced through use of highly active chain transfer agents

Growing community of inventors

Ijzendijke, Netherlands

Cornelis J Hosman