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US 2016/0108222 A1Published application
Ethylene interpolymers having improved color
AssigneeNOVA Chemicals (International) S.A.
InventorsFazle Sibtain, Christopher John Brooke Dobbin, Kenneth Edward Taylor, Hamidreza Khakdaman, P Scott Chisholm
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Abstract
This disclosure relates to a continuous solution polymerization process where ethylene interpolymer products having an improved color index; for example, products having higher whiteness (Whiteness Index (WI)) and lower yellowness (Yellowness Index (YI)). Product color was improved by adjusting selected solution polymerization reaction conditions. The disclosed ethylene interpolymer products have improved color relative to comparative polyethylene compositions.
Claims40
A continuous solution polymerization process to provide an ethylene interpolymer product having improved color comprising:
- i) selecting a desired color index value;
- ii) preparing a single site catalyst formulation in a first catalyst solution having a first catalyst solution temperature (CST-1);
- iii) adjusting said CST-1;
- iv) injecting said first catalyst solution, ethylene, a process solvent, optionally one or more α-olefins and optionally hydrogen into a first reactor to produce a first exit stream containing a first ethylene interpolymer in said process solvent;
- v) preparing a first heterogeneous catalyst formulation in a second catalyst solution having a second catalyst solution temperature (CST-2);
- vi) adjusting said CST-2;
- vii) passing said first exit stream into a second reactor and injecting into said second reactor, said second catalyst solution, ethylene, said process solvent, optionally one or more α-olefins and optionally hydrogen to produce a second exit stream containing a second ethylene interpolymer and said first ethylene interpolymer in said process solvent;
- viii) optionally preparing a second heterogeneous catalyst formulation in a third catalyst solution having a third catalyst solution temperature (CST-3);
- ix) optionally adjusting said CST-3;
- x) passing said second exit stream into a third reactor and optionally injecting into said third reactor, said third catalyst solution, ethylene, said process solvent, one or more α-olefins and hydrogen to produce a third exit stream containing an optional third ethylene interpolymer, said second ethylene interpolymer and said first ethylene interpolymer in said process solvent;
- xi) phase separating said third exit stream to recover said ethylene interpolymer product comprising said first ethylene interpolymer, said second ethylene interpolymer and optionally said third ethylene interpolymer, and;
- xii) measuring an observed color index value of said ethylene interpolymer product and adjusting CST-1 and CST-2 and optionally CST-3 to attain said desired color index value.
9 more elements
An ethylene interpolymer product comprising:
- greater than 2.5 ppm of a first total catalytic metal and having a desired color index that is improved relative to a polyethylene composition having less than 2.5 ppm of a second total catalytic metal.
A continuous solution polymerization process to provide an ethylene interpolymer product having improved color comprising:
- i) selecting a desired color index value;
- ii) preparing a single site catalyst formulation in a first catalyst solution having a first catalyst solution temperature (CST-1);
- iii) adjusting said CST-1;
- iv) injecting said first catalyst solution, ethylene, a process solvent, optionally one or more α-olefins and optionally hydrogen into a first reactor to produce a first exit stream containing a first ethylene interpolymer in said process solvent;
- v) preparing a first heterogeneous catalyst formulation in a second catalyst solution having a second catalyst solution temperature (CST-2);
- vi) adjusting said CST-2;
- vii) injecting said second catalyst solution, ethylene, said process solvent, optionally one or more α-olefins and optionally hydrogen into a second reactor to produce a second exit stream containing a second ethylene interpolymer in said process solvent;
- viii) combining said first and said second exit streams to form a third exit stream;
- ix) optionally preparing a second heterogeneous catalyst formulation in a third catalyst solution having a third catalyst solution temperature (CST-3);
- x) optionally adjusting said CST-3;
- xi) passing said third exit stream into a third reactor and optionally injecting into said third reactor, said third catalyst solution, ethylene, said process solvent, one or more α-olefins, hydrogen to produce a fourth exit stream containing an optional third ethylene interpolymer, said second ethylene interpolymer and said first ethylene interpolymer in said process solvent;
- xii) phase separating said fourth exit stream to recover said ethylene interpolymer product comprising said first ethylene interpolymer, said second ethylene interpolymer and optionally said third ethylene interpolymer, and;
- xiii) measuring an observed color index value of said ethylene interpolymer product and adjusting said CST-1 and said CST-2 and optionally said CST-3 to attain said desired color index value.
10 more elements
Dependencies are inferred from the claim text.