Method for recovering organic fibers from a composite material

Patent metadata

Field	Value
Publication number	US-2016145409-A1
Application number	US-201414899420-A
Country	US
Kind code	A1
Filing date	Jun 19, 2014
Priority date	Jun 20, 2013
Publication date	May 26, 2016
Grant date	—

Abstract

The invention relates to a method for recovering organic fibers from a composite material comprising a polymer matrix and organic fibers, wherein the method comprises the following steps: providing a solution comprising a mixture of water and alcohol; placing the composite material inside a reactor; contacting the mixture and the composite material in order to perform a solvolysis reaction of the composite material; and recovering the organic fibers; wherein the pressure and the temperature in the reactor are adjusted such as to fall within the homogeneous sub-critical range of the phase diagram, within the super-critical range or near the critical point; and wherein the temperature is lower than the melting temperature of the organic fibers.

First claim

1 . A method for recovering organic fibers from a composite material comprising a polymer matrix and organic fibers, the method comprising the following steps:
providing a solution comprising a mixture of water and alcohol; disposing the composite material inside a reactor; placing the mixture in contact with the composite material in order to carry out a solvolysis reaction of the polymer matrix of the composite material; recovering the organic fibers; wherein the pressure and temperature in the reactor are adjusted so as to fall within the homogeneous subcritical region of the phase diagram, within the supercritical region, or near the critical point; and wherein the temperature is below the degradation temperature of the organic fibers.

2 . The method according to claim 1 , wherein the temperature and/or pressure is supercritical.

3 . The method according to claim 1 , wherein the organic fibers are aramid fibers and the temperature is set to at most 300° C.

4 . The method according to claim 3 , wherein the aramid fibers are selected from: meta-aramid fibers, para-aramid fibers, para-aramid and meta-aramid copolymer fibers, or a mixture thereof.

5 . The method according to claim 1 , wherein the organic fibers are plant fibers.

6 . The method according to claim 5 , wherein the plant fibers are selected from the group consisting of: flax fibers, banana fibers, hemp fibers, nettle fibers, coconut fibers, cotton fibers, henequen fibers, sisal fibers, jute fibers, ramie fibers, fibers from wheat straw or any other grain, wood fibers, or a mixture thereof.

7 . The method according to claim 1 , wherein the polymer matrix is thermoset polymer or thermoplastic polymer.

8 . The method according to claim 1 , wherein the mixture of water and alcohol has a water/alcohol volume ratio of between 30:70 and 70:30.

9 . The method according to claim 1 , wherein the mixture and the composite material are placed in contact for 15 to 105 minutes.

10 . The method according to claim 1 , wherein the mixture and the composite material are placed in contact by circulating a stream of the mixture through the reactor inside which the composite material is disposed.

11 . The method according to claim 1 , further comprising the step consisting in reducing the composite material to granules before being placed in contact with the mixture.

12 . The method according to claim 1 , further comprising the recovery of effluent produced by the solvolysis and discharged outside the reactor; and
optionally the burning of the effluent to heat the reactor.

Assignees

• Centre Nat Rech Scient
• Univ Bordeaux 1
• Airbus Ind Gie

Inventors

• Aymonier Cyril
• Loppinet Serani Anne
• Debeauvais Antoine

Classifications

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title

• C08J2377/00

  Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers · CPC title

• C08J2301/02

  Cellulose; Modified cellulose · CPC title

• C08J11/24 Primary

  containing hydroxyl groups · CPC title

• B29B2017/0293

  Dissolving the materials in gases or liquids · CPC title