Biodegradable Microbeads from Mixed Cellulose Esters
AssigneeEastman Chemical Company
InventorsRobert David Pace, Deepika Saini, Sharmistha Mazumder, Garry Kenneth Weakley, Marcie Anne Natale, Timothy R Pitts, Glenn Lewis Shoaf, Matt Stephens, Hassan Alomgir Ali
Life of this patent
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Abstract
Biodegradable beads are provided that are formed from mixed cellulose esters, such as cellulose acetate butyrate or cellulose acetate propionate. The biodegradable beads and mixed cellulose esters are both freshwater biodegradable and may be used in various downstream applications where biodegradable components are desired and sought.
Claims20
A biodegradable bead comprising a mixed cellulose ester,
- wherein the biodegradable bead exhibits at least 40 percent biodegradability at 56 days according to the OECD 301F test method,
- wherein the mixed cellulose ester comprises—
- (a) an acetyl substituent and an average degree of substitution for acetyl substituents (“DSAc”) of less than 2.3,
- (b) an average degree of substitution for propionyl substituents (“DSPr”) or an average degree of substitution for butyryl substituents (“DSBu”) of at least 0.1, and
- (c) an average degree of substitution for hydroxyl substituents (“DSOH”) of at least 0.6.
A biodegradable bead comprising a mixed cellulose ester and an additional biodegradable cellulose ester,
- wherein the biodegradable bead exhibits at least 40 percent biodegradability at 56 days according to the OECD 301F test method,
- wherein the mixed cellulose ester comprises—
- (a) an acetyl substituent and an average degree of substitution for acetyl substituents (“DSAc”) of less than 2.3,
- (b) an average degree of substitution for propionyl substituents (“DSPr”) or an average degree of substitution for butyryl substituents (“DSBu”) of at least 0.1, and
- (c) an average degree of substitution for hydroxyl substituents (“DSOH”) of at least 0.6.
A process for forming biodegradable beads, the process comprising:
- (a) forming a dope comprising a mixed cellulose ester, wherein the mixed cellulose ester comprises—
- (i) an acetyl substituent and an average degree of substitution for acetyl substituents (“DSAc”) of less than 2.3,
- (ii) an average degree of substitution for propionyl substituents (“DSPr”) or an average degree of substitution for butyryl substituents (“DSBu”) of at least 0.1, and
- (iii) an average degree of substitution for hydroxyl substituents (“DSOH”) of at least 0.6;
- (b) contacting at least a portion of the dope with an aqueous mixture under agitation to thereby form a reaction mixture comprising a plurality of biodegradable beads;
- and
- (c) recovering at least a portion of the biodegradable beads from the reaction mixture, wherein the biodegradable beads exhibit at least 40 percent biodegradability at 56 days according to the OECD 301F test method.
Dependencies are inferred from the claim text.