Flame-retardant treatment of lignocellulosic materials, resulting flame-retarded lignocellulosic materials and uses thereof

Patent metadata

Field	Value
Publication number	US-11964407-B2
Application number	US-202117917138-A
Country	US
Kind code	B2
Filing date	Apr 8, 2021
Priority date	Apr 9, 2020
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

A flame retardant treatment of a lignocellulosic material, which includes: optionally steam exploding the lignocellulosic material, impregnating the optionally steam-exploded lignocellulosic material, in or with an aqueous solution, from 0.5% to 10% of phytic acid and from 1% to 30% of urea, based on the total weight of the aqueous solution, optionally drying of the impregnated lignocellulosic material, until the impregnated lignocellulosic material has a moisture content from 5% to 20% by weight, cooking the impregnated and optionally dried lignocellulosic material, the resulting flame-retarded lignocellulosic material including a phosphorous content originating from the phytic acid from 0.1% to 10% by weight. Also, the resulting flame-retarded lignocellulosic material and the use thereof for manufacturing flame-retarded composite materials based on plant fibres, woven or nonwoven flame-retarded flexible materials based on plant fibres, and particularly textiles, flame-retarded materials based on wood fibres and/or on wood particles, and particularly flame-retarded wood panels.

First claim

The invention claimed is:

1. A process for preparing a biobased flame-retarded lignocellulosic material from biobased lignocellulosic material, comprising the following steps:
optionally steam exploding and/or bleaching the biobased lignocellulosic material,
impregnating the biobased lignocellulosic material, optionally steam-exploded and/or bleached, in or with an aqueous solution consisting of: from 0.5% to 7% phytic acid and from 1% to 22% urea, said percentages being expressed by mass relative to the total mass of the aqueous solution, with a balance of the aqueous solution being water,
optionally drying the impregnated biobased lignocellulosic material until it has a moisture content ranging from 5% to 20%, said percentages being expressed by mass relative to the total mass of the impregnated biobased lignocellulosic material,
cooking the impregnated and optionally dried biobased lignocellulosic material,

the biobased flame-retarded lignocellulosic material thus obtained comprising a content of phosphorus originating from phytic acid ranging from 0.1% to 10%, said percentages being expressed by mass relative to the total mass of the biobased flame-retarded lignocellulosic material,
wherein said biobased flame-retarded lignocellulosic material consists of said biobased lignocellulosic material impregnated in or with the aqueous solution, and said biobased lignocellulosic material has not undergone any chemical treatment other than optionally steam exploding and/or bleaching.

2. The process as claimed in claim 1 , wherein the biobased lignocellulosic material is in a form selected from the group consisting of plant fibers, wood fibers, wood particles, and mixtures thereof.

3. The process as claimed in claim 2 , wherein:
the plant fibers are bast fibers selected from the group consisting of hemp, flax, ramie and jute fibers, and
the wood fibers and/or the wood particles are from wood selected from the group consisting of spruce, ash, birch, poplar, beech and oak.

4. The process as claimed in claim 2 , wherein the biobased lignocellulosic material is in the form of bast fibers.

5. The process as claimed in claim 1 , wherein the biobased lignocellulosic material is steam exploded and is selected from the group consisting of steam-exploded plant fibers, steam-exploded wood fibers, steam-exploded wood particles, and combinations thereof.

6. The process as claimed in claim 5 , wherein the steam-exploded plant fibers, have a diameter of less than 100 μm and a length ranging from 1 cm to 10 cm.

7. The process as claimed in claim 5 , wherein the biobased lignocellulosic material is steam-exploded bast fibers.

8. The process as claimed in claim 1 , wherein the biobased lignocellulosic material is bleached.

9. The process as claimed in claim 1 , wherein the phytic acid used is obtained from a rapeseed oil cake.

10. The process as claimed in claim 1 , wherein the step of impregnating the biobased lignocellulosic material is performed at room temperature:
by soaking in the aqueous solution of phytic acid and urea, or
by spraying with the aqueous solution of phytic acid and urea.

11. The process as claimed in claim 10 , wherein the step of impregnating the biobased lignocellulosic material is performed at room temperature by soaking in the aqueous solution of phytic acid and urea, and the impregnated biobased lignocellulosic material is subjected to the step of drying before the step of cooking.

12. The process as claimed in claim 1 , wherein the step of drying of the impregnated biobased lignocellulosic material is performed at a temperature ranging from 20° C. to 60° C., for a time ranging from 5 minutes to 18 hours.

13. The process as claimed in claim 1 , wherein the step of cooking of the impregnated and optionally dried biobased lignocellulosic material is performed at a temperature ranging from 140° C. to 200° C., for a time ranging from 15 minutes to 5 hours.

14. The process as claimed in claim 1 , wherein, in the biobased flame-retarded lignocellulosic material, the phosphorus originating from the phytic acid is grafted by covalent bonding to the surface and to the core of said biobased flame-retarded lignocellulosic material.

15. The method as claimed in claim 1 , wherein the biobased flame-retarded lignocellulosic material obtained comprises a content of phosphorus originating from phytic acid ranging from 0.3% to 3%, said percentages being expressed by mass relative to the total mass of the flame-retarded biobased lignocellulosic material.

16. A method of manufacturing flame-retarded composite materials based on plant fibers, flexible flame-retarded woven or nonwoven materials based on plant fibers, or flame-retarded materials based on wood fibers and/or wood particles, comprising providing the biobased flame-retarded lignocellulosic material as obtained according to the process claim 1 , wherein the biobased lignocellulosic material from which the biobased flame-retarded lignocellulosic material is prepared is plant fibers or wood fibers and/or wood particles.

17. The method as claimed in claim 16 , wherein the flame-retarded composite materials are flame-retarded wood panels, and the biobased flame-retarded lignocellulosic material is obtained from steam-exploded wood fibers and/or steam-exploded wood particles, and the flame-retarded wood panels obtained are free of glue and resin.

18. The method as claimed in claim 16 , wherein the flame-retarded composite materials are flame-retarded textiles, the biobased flame-retarded lignocellulosic material is obtained from plant fibers.

Assignees

• Univ De Lorraine
• Inst Mines Telecom
• Univ Libanaise

Inventors

• Brosse Nicolas
• Kapel Romain
• Sonnier Rodolphe
• El Hage Roland
• Segovia César
• Antoun Karina
• Moussa Maria

Classifications

• B27K3/0207 Primary

  Pretreatment of wood before impregnation · CPC title

• B27K3/346

  Grafting onto wood fibres (B27K3/156 takes precedence; macromolecular compounds derived from lignocellulosic materials C08H) · CPC title

• B27K3/36

  Aliphatic compounds · CPC title

• B27K3/38

  Aromatic compounds {(B27K3/343 takes precedence)} · CPC title

• B27K3/50

  Mixtures of different organic impregnating agents · CPC title