Process for manufacturing a thermoformable plasticized composite containing cellulose fiber and a moldable polymer
The present invention concerns a process for manufacturing a thermoformable plasticized composite containing cellulose fiber and polylactide by blending the dry cellulose fiber and a compatibilizer in a compactor into pellets, and subsequently reacting the reactive compatibilizer and the mixture of cellulose fiber and polylactide by compounding. The invention also concerns a composite manufactured using said process, as well as further processed products.
1. A process for manufacturing a thermoformable plasticized composite from cellulose fiber and a moldable polymer comprising;
compacting dry cellulose fibers having a dry matter content ranging from 55 wt % to 99.9 wt % and one or more compatibilizers into a compressed biomaterial to form compatibilizer-containing cellulose pellets;
reacting the compatibilizer-containing cellulose pellets and a moldable polymer by compounding them into a thermoformable plasticized composite;
wherein the one or more compatibilizers comprises at least one of ≧C8 aliphatic linear or branched organic compounds containing epoxy, silicate, or hydroxyl functionalities or a silicone derivative containing epoxy, hydroxyl, or double bond functionalities, and
wherein the thermoformable plasticized composite has cross-linking by covalent bonds formed between the dry cellulose fibers and the polymer.
2. The process according to claim 1 , wherein the dry cellulose fibers are obtained from wood material from softwood trees or wood material from hardwood trees or from non-wood materials, or grasses, straw, leaves, bark, seeds, hulls, flowers, vegetables or fruits.
3. The process according to claim 1 , wherein the moldable polymer is selected from polylactide, polyethylene, polypropylene, polyhydroxyalkanoates, thermoplastic polyesters and polyamides.
4. The process according to claim 1 , wherein the dry cellulose fibers and the moldable polymer are pressed through openings of a dry compactor 1-20 times.
5. The process according to claim 1 , wherein the dry cellulose fibers and the moldable polymer are pressed through openings of a compactor more than one time, using sequential compactors.
6. The process according to claim 1 , wherein compacting and densifying of the material suitable for feeding to a compounder takes place by pressing the compatibilizer-containing cellulose pellets and the moldable polymer against a perforated pan plate of a compactor with help of rollers of a roller mill.
7. The process according to claim 1 , wherein the temperature of the biomaterial is increased to above room temperature during compacting, to a maximum temperature of 70° C.
8. The process according to claim 1 , which is operated at a dry-matter content of above 30%.
9. The process according to claim 1 , wherein the drying of the compatibilizer-containing cellulose pellets occurs in an oven at mild temperatures between 40-60° C.
10. The process according to claim 1 , wherein the compounding is carried out using melt-processing, or extrusion, or injection molding, whereby the composite is in the form of a film or molded structure.
11. A thermoformable plasticized composite containing cellulose fiber and polylactide, wherein it has been manufactured using a process comprising;
blending dry cellulose fibers having a dry matter content ranging from 55 wt % to 99.9 wt % and one or more compatibilizers to form compatibilizer-containing cellulose pellets;
drying the compatibilizer-containing cellulose pellets;
reacting the compatibilizer-containing cellulose pellets and polylactide by compounding-them into a thermoformable plasticized composite,
wherein the one or more compatibilizers is selected from the group consisting of ≧C8 aliphatic linear or branched organic compounds containing epoxy, silicate, or hydroxyl functionalities or a silicone derivative containing epoxy, hydroxyl, or double bond functionalities, and
wherein the thermoformable plasticized composite has cross-linking by covalent bonds formed between the dry cellulose fibers and the polymer.
12. The process according to claim 8 , wherein the dry-matter content is achieved without the use of any added solvent.
13. The process according to claim 1 , wherein the one or more compatibilizers comprise a tall oil fatty acid (TOFA) anhydride, TOFA ester epoxide, a Cardanol epoxide, or a combination thereof.
14. The process according to claim 1 , wherein the moldable polymer comprises polylactic acid.
15. The process according to claim 1 , further comprising processing cellulose containing raw materials prior to use by refiner mechanical pulping, pressurized refiner mechanical pulping, thermomechanical pulping, groundwood, pressurized groundwood, or chemithermomechanical pulping.
16. The process according to claim 1 , wherein the drying occurs at a temperature ranging from 40° C. to 60° C.
17. The process according to claim 1 , wherein the process is carried out at a temperature below 200° C.