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US 7,683,137 B2Granted
Color reduction polyethylene modified by radical initiation
AssigneeFina Technology, Inc.
InventorsVincent Henri Barre, Tim J. Coffy, Cyril Chevillard
Life of this patent
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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.
Claims8
A method for producing polyethylene having reduced color comprising
- polymerizing ethylene monomer in the presence of at least one free radical initiator as a polymerization mixture;
- and
- incorporating into the polymerization mixture an amount effective to reduce a yellow index of a polyethylene product an additive selected from the group consisting of alcohols, glycols, and water steam, and a neutralizing species selected from the group consisting of alkali metal stearates, alkali earth metal stearates, zinc stearate, calcium oxide and zinc oxide and combinations thereof.
A method for producing polyethylene having reduced color comprising
- polymerizing ethylene monomer in the presence of at least one free radical initiator as a polymerization mixture;
- and
- incorporating into the polymerization mixture an additive selected from the group consisting of alcohols, glycols, and water steam, in a proportion between about 5 and about 1000 ppm, a stearate selected from the group consisting of alkali metal stearates, alkali earth metal stearates, zinc stearate, in a proportion between about 300 to about 2000 ppm, and zinc oxide or calcium oxide in a proportion between about 300 to about 4000 ppm;
- all based on the polymerization mixture;
- where the polyethylene product has reduced yellow index as compared with an identical polyethylene product absent the additive.
2 more elements
Dependencies are inferred from the claim text.