1. A method for preparation of expanded polylactide bead foams comprising the following steps:
A) providing unfoamed polylactide pellets,
B) heating said unfoamed polylactide pellets to an annealing temperature and saturating with a blowing agent,
C) maintaining said polylactide pellets on the annealing temperature and saturating with said blowing agent,
D) depressurizing and cooling the saturated polylactide pellets of step C) to room temperature to form expanded polylactide bead foams.
2. The method according to claim 1, in which the annealing temperature is in the range of 60\xb0 C.-180\xb0 C.
3. The method according to claim 1, in which the annealing time during step C) is in the range of 10 min-300 min.
4. The method according to claim 1, in which the polylactide pellets in step A) are chosen from the group of linear polylactide, branched polylactide and polylactide copolymers with D-lactide contents, or combinations thereof.
5. method according to claim 4, in which step B) takes place in a suspension medium.
6. A method according to claim 4, in which the polylactide pellets in step A) are mixed with polyolefins andor polyesters.
7. An expanded polylactide bead foam having a double crystal melting peak, in which the distance between the two peaks is in the range of 5\xb0 C.-25\xb0 C.
8. (canceled)
9. The polylactide bead according to claim 7, in which the distance between the two peaks is in the range of 10\xb0 C.-20\xb0 C.
10. The polylactide bead according to claim 7, in which the polylactide beads are chosen from the group of linear polylactide, branched polylactide and PLA copolymers with D-lactide contents, or combinations thereof.
11. The polylactide bead according to claim 7, in which the polylactide beads include one or more additives chosen from the group of chain extender, nanoparticles, micro-sized solid particles, fibers, and lubricants.
12. The polylactide beads according to claim 7, in which the polylactide beads include polyolefins andor polyesters.
13. A method for the moulding of foam beads in which foamed beads are sintered in the presence of hot air andor steam, wherein as said foamed beads comprises the polylactide beads according to claim 7.
14. A foam moulding comprising sintered polylactide beads having a double crystal melting peak.
15. A packaging material, thermal insulation material, sound insulation material, construction material, or cushioning material comprising the foam moulding according to claim 14.
16. The method according to claim 2, in which the annealing temperature is about the melting peak of said polylactide pellets.
17. The method according to claim 4, in which step B) takes place in water.
18. The method according to claim 5, in which the polylactide pellets in step A) are mixed with polyolefins andor polyesters.
19. The method according to claim 1, in which said blowing agent is chosen from the group of organic compounds and volatile compounds.
20. The method according to claim 1, in which said blowing agent comprises CO2.
21. The polylactide bead according to claim 9, in which the polylactide beads are chosen from the group of linear polylactide, branched polylactide and PLA copolymers with D-lactide contents, or combinations thereof.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of preparing cyclic esters from 5 or 6 carbon compounds comprising, contacting a column bed containing a solid acid catalyst with at least one starting 5 or 6 carbon compound selected from the group consisting of a sugar alcohol, a monoanhydrosugar alcohol, and a dianhydrosugar alcohol in the presence of an organic acid in a single step reaction under a single set of reaction conditions for a time sufficient to form at least one of a cyclic monoester and cyclic diester derivative of at least one of the monoanhydrosugar alcohol and a dianhydrosugar alcohol.
2. The method of claim 1, wherein the bed is configured in a simulated moving bed apparatus.
3. The method of claim 1, wherein the organic acid is acetic acid.
4. The method of claim 1, wherein the starting 5 or 6 carbon compound is selected from group consisting of sorbitol, isosorbide and sorbitan.
5. The method of claim 1, wherein the starting 5 or 6 carbon compound is selected from the group consisting of arabinitol, ribitol, sorbitol, mannitol, isomannide, galactitol, iditol and xylitol.
6. The method of claim 1, wherein the solid acid catalyst is an ion exchange resin.
7. The method of claim 1, wherein the solid acid catalyst is a zeolite catalyst.
8. The method of claim 6, wherein the solid acid catalyst is selected from the group consisting of Amberlyst 35, Amberlyst 15, Amberlyst 36, Amberlyst 70, and Amberlyst 131; Purolite CT-145, Lewatit S2328, Lewatit K2431, Lewatit S2568, Lewatit K2629, SK104, PK228, RCP 160 and Relite RADF.
9. The method of claim 6, wherein the solid acid catalyst is Amberlyst 35.
10. The method of claim 1, wherein the 5 or 6 carbon starting compound is recycled back onto the column bed.
11. The method of claim 1, wherein the single step reaction under a single set of reaction conditions comprises an initial reaction temperature selected from the range of temperatures from 70\xb0 to 100\xb0 C., and wherein the reaction temperature remains constant at the initial reaction temperature.
12. The method of claim 1, wherein the single step reaction is conducted in the presence of water.
13. The method of claim 1, further comprising:
recycling at least one of a cyclic monoester and cyclic diester derivative of at least one of the monoanhydrosugar alcohol and a dianhydrosugar alcohol back onto the column bed to form at least one of a cyclic monoester and cyclic diester derivative of at least one of the monoanhydrosugar alcohol and a dianhydrosugar alcohol.