Production of high performance thermoplastic composites

Patent metadata

Field	Value
Publication number	US-10449694-B2
Application number	US-201415028441-A
Country	US
Kind code	B2
Filing date	Oct 9, 2014
Priority date	Oct 9, 2013
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

The present invention concerns a process for producing a thermoformable porous web using a mixture of cellulosic fibers and one or more thermoplastic materials, particularly by foam forming said mixture into a composite foam, and applying the foam into one or more layers on a support to obtain a porous pre-form web. The thus produced porous composite web can be further processed by compression molding to give a rigid high-strength composite structure, which is suitable for use in producing, e.g. panels or plates, packages or hygiene products, insulators or filters, or printed intelligence, electronics or microcellulose products.

First claim

The invention claimed is:

1. A process for producing a thermoformable porous web using cellulosic fibres and one or more thermoplastic materials by foam forming a mixture of the cellulosic fibres and the thermoplastic material(s) into a composite foam, and applying the foam on a wire to obtain a porous pre-form web, wherein the cellulosic fibres are selected from fibres of pure cellulose or from fibres of cellulose derivatives, and wherein the one or more thermoplastic materials comprise lignin.

2. The process according to claim 1 , further comprising obtaining the cellulosic fibres from wood pulp obtained from chemical, mechanical, thermomechanical or chemithermomechanical pulping, or from recycled pulp or from agricultural fibres, or from thermo-mechanical pulp (TMP) or hot-water-extracted pulp (HWE), optionally being bleached.

3. The process according to claim 1 , wherein the thermoplastic material(s) further comprise a member from group consisting of polylactic acid (PLA), polyglycolic acid (PGA), polyolefins, polyamides, polyvinyl chloride (PVC), polyesters, polyvinyl alcohol (PVA), polycarbonate (PC), thermoplastic polyurethane (TPU), polyphenylene sulphide (PPS), polyetherimide (PEI), polystyrenes, thermoplastic or native starch, and derivatives of the above.

4. The process according to claim 1 , wherein the content of cellulosic fibres in the composite foam is 20-90 w-%.

5. The process according to claim 1 , wherein the content of thermoplastic material(s) in the composite foam is 10-80 w-%.

6. The process according to claim 1 , further comprising carrying out the foam forming by adding water into the mixture of fibre and thermoplastic(s) by adding a foaming agent, and by stirring efficiently to give the composite foam.

7. The process according to claim 1 , further comprising adding one or more compatibilizers into the thermoplastic component(s) before mixing with the cellulosic fibres, or into the mixture of the fibres and the thermoplastic material(s), or into the composite foam.

8. The process according to claim 1 , further comprising adding one or more cross-linking agents into the thermoplastic component(s) before mixing with the cellulosic fibres, by adding the one or more cross-linking agents into the mixture during the foam forming, by spraying the one or more cross-linking agents onto the pre-form web, or by impregnating the one or more cross-linking agents into the web.

9. The process according to claim 1 further comprising producing thermoplastic-cellulosic fibre prepregs from the thermoformable porous web by one of the following steps:
a. draining the web on a wire, compacting the web into pellets and drying the pellets, or
b. draining the web on a wire, pressing the web to a desired solid consistency, drying the web, cutting the web to mats and dicing the mats to smaller particles, or
c. draining the web on a wire, pressing the web to a desired solid consistency, drying the web and winding the web into a roll.

10. The process according to claim 9 , comprising carrying out step a), wherein the web is first drained to a solid consistency of 30-70 weight-% on a wire and then compacted into pellets having an average size of 0.2 mm-40 mm (width) and 0.2 mm-40 mm (length), followed by drying the pellets.

11. The process according to claim 9 , wherein a compacting, cutting or winding device is placed at the end of a foam laid forming line, thus enabling a continuous production process.

Assignees

• Teknologian Tutkimuskeskus Vtt Oy

Inventors

• Ojala Antti
• Nättinen Kalle
• Wikström Lisa
• Minkkinen Hannu
• Jetsu Petri
• Lehmonen Jani
• Kinnunen Karita
• Hjelt Tuomo

Classifications

• C08J2201/026

  Crosslinking before of after foaming · CPC title

• B29K2201/08

  Cellulose derivatives · CPC title

• B29K2201/12

  Cellulose acetate · CPC title

• B29K2105/0005

  containing compounding ingredients (releasing, lubricating or separating agents B29C33/56, fibers B29K2105/08, B29K2105/12; fillers B29K2105/16, recycled material B29K2105/26) · CPC title

• B29K2105/04

  cellular or porous · CPC title