Claims
- 1. A biodegradable thermoplastic material comprising a natural polymer, a plasticizer and an exfoliated clay having a layered structure, said clay having a cation exchange capacity of from 30 to 250 milliequivalents per 100 grams.
- 2. The material of claim 1, wherein the cation exchange capacity is from 50 to 200 milliequivalents.
- 3. The material of claim 1, wherein the clay is a smectite clay mineral.
- 4. The material of claim 1, wherein the clay is present in an amount of from 0.1 to 90 wt. %, based on the weight of the biodegradable thermoplastic material.
- 5. The material of claim 1, wherein the natural polymer is a carbohydrate or a protein.
- 6. The material of claim 5, wherein the natural polymer is chosen from the group consisting of starch, cellulose, chitosan, alginic acid, inulin, pectin, and combinations thereof.
- 7. The material of claim 1, wherein the plasticizer is selected from the group consisting of water, glycerol, ethylene glycol, an oligomer of ethylene glycol and combinations thereof.
- 8. The material of claim 1, wherein the plasticizer is present in an amount of 15 to 60 wt. %, based on the weight of the biodegradable thermoplastic material.
- 9. An article of manufacture comprising a biodegradable thermoplastic material according to claim 1.
- 10. A process for preparing a biodegradable thermoplastic material according to claim 1, comprising preparing a suspension of the clay in water and/or another plasticizer, and extruding the suspension together with the natural polymer and the plasticizer at a temperature of from 35 to 200° C.
- 11. A process according to claim 10, wherein the suspension of the clay is heated before extrusion to a temperature of up to 60° C. in order to exfoliate the clay.
- 12. A process according to claim 10, wherein the clay suspension is ion exchanged with at least part of the natural polymer.
- 13. A process according to claim 10, wherein the clay suspension is ion exchanged with a modifying agent, the modifying agent being a surfactant having from 6 to 16 carbon atoms, a functionality compatible with the natural polymer and an ammonium, phosphonium or sulfonium group.
- 14. A method of improving the stability of a biodegradable thermoplastic material containing a natural polymer and a plasticizer, comprising:a) preparing a suspension of clay having a cation exchange capacity of from 30 to 250 milliequivalents per 100 grams in water, said suspension optionally containing a plasticizer; b) combining said suspension with a natural polymer and a plasticizer; and c) extruding the resultant composition at a temperature of between 35 and 200° C.
- 15. The method of claim 14, wherein said claim is exfoliated.
Priority Claims (1)
Number |
Date |
Country |
Kind |
00200896 |
Mar 2000 |
EP |
|
Parent Case Info
This application is a 371 of PCT/NL01/00206 dated Mar. 13, 2001.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/NL01/00206 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO01/68762 |
9/20/2001 |
WO |
A |
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4737582 |
Goldman et al. |
Apr 1988 |
A |
4963192 |
Dessauer |
Oct 1990 |
A |
5858076 |
Thompson |
Jan 1999 |
A |
Foreign Referenced Citations (1)
Number |
Date |
Country |
0 691 381 |
Jan 1995 |
EP |