Method for Producing Wood Fibre Pellets

• US 20090229771A1
• Filed: 06/23/2005
• Published: 09/17/2009
• Est. Priority Date: 06/23/2004
• Status: Active Grant

• Current Assignee: New Zealand Forest Research Institute Limited
• Original Assignee: New Zealand Forest Research Institute Limited
• Inventors: Witt, Michael Ralph Juergen, Fernyhough, Alan, Lee, Brendan James, Anderson, Charles Ross, Warnes, Jeremy Martin
• Granted Patent: US 9,511,508 B2
• Time in Patent Office: Days
• US Class Current: 162/28
• CPC Class Codes: B27N 1/00 Pretreatment of moulding material
• CPC Class Codes: B27N 1/02 Mixing the material with binding agent mixing in general B01F
• CPC Class Codes: B27N 3/002 characterised by the type of binder compositions of macromolecular compounds C08L
• CPC Class Codes: B27N 3/04 from fibres
• CPC Class Codes: B29B 7/905 with means for pretreatment of the charges or fibres
• CPC Class Codes: B29B 7/92 Wood chips or wood fibres
• CPC Class Codes: B29B 9/04 in the form of plates or sheets
• CPC Class Codes: B29B 9/14 fibre-reinforced
• CPC Class Codes: B29B 9/16 Auxiliary treatment of granules

Abstract

A process for producing pellets or granules comprising fibres of a lignocellulousic material, for use as a feedstock in plastics manufacture, conveying in a dry or wet air stream and applying to the fibres a liquid formulation comprising one or more polymers, monomers, or oligomers, forming the fibres into a solid product, and breaking down the solid product to produce said pellets or granules. Typically the conduit conveys the fibres in a plant for manufacture of fibre board.

Claims

1. :

A process for producing pellets or granules (as herein defined) comprising fibres of a lignocellulousic material or natural fibres, for use as a feedstock in plastics manufacture, which comprises;

conveying loose or divided fibres or fibre bundles, produced by mechanically or thermomechanically or chemo-thermomechanically or chemo-mechanically breaking down a lignocellulousic material, or natural fibres, in a dry or wet air stream and applying to the fibres while so conveying the fibres a liquid formulation comprising one or more polymers, monomers, or oligomers, forming the fibres into a solid product, and breaking down the solid product to produce said pellets or granules.

2. :

The process according to claim 1 including conveying the fibres along a conduit in a dry or wet stream and introducing the formulation of the polymer, mononmer or oligiomer into the interior of the conduit to apply the formulation to the fibres while the fibres are moving through the conduit.

3. :

The process according to claim 2 including introducing the formulation into the conduit by spraying the formulation into the interior of the conduit as the fibres move through the conduit, to coat or partially coat the fibres.

4. :

The process according to claim 3 wherein the conduit conveys the fibres from a refiner stage in a plant for manufacture of fibre board.

5. :

The process according to claim 4 wherein the conduit conveys the fibres to or from a drying stage or drier.

6. :

The process according to claim 1 including forming the fibres into a solid product by pressing the fibres to a solid product in planar form.

7. :

The process according to claim 6 including pressing the fibres between heated plattens.

8. :

The process according to claim 6 including pressing the fibres into a sheet of up to about 2 cm in thickness.

9. :

The process according to claim 6 including pressing the fibres into a sheet of up to about 1 cm in thickness.

10. :

The process according to claim 1 including breaking down said solid product to said pellets or granules by cutting or sawing the solid product.

11. :

The process according to claim 1, wherein the fibres have an average fibre length or fibre-bundle length of at least about 0.8 mm.

12. :

The process according to claim 1, wherein the fibres have an average fibre length of loose fibres or of fibre bundles of at least about 1 mm.

13. :

The process according to claim 11, wherein a major fraction of the fibres have an aspect ratio of at least 10;

1.

14. :

The process according to claim 11, wherein a major fraction of the fibres have an aspect ratio of at least 20;

1.

15. :

The process according to claim 11, wherein a major fraction of the fibres have an aspect ratio of at least 25;

1.

16. :

The process according to claim 1, including breaking down the solid product to produce pellets which are longer than the average fibre length of the fibres within the pellets.

17. :

The process according to claim 1 wherein the fibres are wood fibres.

18. :

The process according to claim 1 including breaking down the solid product down to produce pellets or granules by chopping and including applying to the fibres sufficient of the polymer, monomer or oligomer formulation to bind the fibres together to withstand pelletisation or granulisation by chopping.

19. :

The process according to claim 1, wherein the pellets or granules comprise between 0.3 to 25 parts of the polymer per 100 parts of fibre by dried weights.

20. :

The process according to claim 1 wherein the liquid formulation is an aqueous solution, dispersion or emulsion.

21. :

The process according to claim 1 wherein the formulation comprise(s) a thermoplastic polymer.

22. :

The process according to claim 21 wherein the thermoplastic polymer has a melting point below 230°

C.

23. :

The process according to claim 21 wherein the thermoplastic polymer has a melting point below 200°

C.

24. :

The process according to claim 23, wherein the polymer is a polyvinyl alcohol, polyvinyl acetate, polyester, starch based, or a polymer or copolymer with one or more of an acid, anhydride, epoxy, amine, isocyanate, silane, or silanol group.

25. :

The process according to claim 24 including subsequently applying one or more second polymers, monomers, or oligomers or paraffin or wax to the fibres

26. :

The process according to claim 6 wherein said pressing step comprises first and second pressing operations, said second pressing operation being carried out at a higher temperature than said first pressing operation.

30. :

The pellets or granules produced by claim 1.

31. :

The process for manufacture of plastics products or intermediates which includes introducing pellets or granules by the process of claim 1 as a feedstock into a plastics extrusion or moulding machine.

27. :

A process for producing pellets or granules (as herein defined) comprising fibres of a lignocellulousic material or natural fibres, for use as a feedstock in plastics manufacture, which comprises;

conveying loose or divided fibres or fibre bundles, produced by mechanically or thermomechanically or chemo-thermomechanically or chemo-mechanically breaking down a lignocellulousic material, or natural fibres, along a conduit in a dry or wet air stream, applying to the fibres a liquid formulation comprising one or more polymers, monomers, or oligomers, by spraying the formulation onto the fibres to coat or partially coat the fibres, forming the fibres into a solid product, and breaking down the solid product to produce said pellets or granules.

28. :

The process according to claim 27 wherein the conduit conveys the fibres from a refiner stage in a plant for manufacture of fibre board and including forming the fibres into a solid product by pressing the fibres to a solid product in planar form.

29. :

A process for producing pellets or granules (as herein defined) comprising wood fibres, for use as a feedstock in plastics manufacture, which comprises applying to wood fibres or fibre bundles, produced by mechanically or thermomechanically or chemo-thermomechanically or chemo-mechanically breaking down solid wood, a liquid formulation comprising one or more polymers, monomers, or oligomers to coat or partially coat the fibres, pressing the fibres into a solid product, and breaking down the solid product into wood fibre-containing pellets or granules.