Method of producing a fibrous material pre-impregnated with thermoplastic polymer in a fluid bed

Patent metadata

Field	Value
Publication number	US-10974418-B2
Application number	US-201515118188-A
Country	US
Kind code	B2
Filing date	Feb 11, 2015
Priority date	Feb 13, 2014
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

A method of producing a pre-impregnated fibrous material including a fibrous material of continuous fibres and a thermoplastic polymer matrix, wherein the pre-impregnated fibrous material is produced in a single unidirectional strip or in a plurality of parallel unidirectional strips, the method including the following steps: (i) impregnating the fibrous material in the form of a strand or a plurality of parallel strands with the thermoplastic polymer in the form of a powder in a fluid bed; and (ii) shaping the strand or parallel strands of the fibrous material impregnated as in step (i) by calendering by at least one heating calender in the form of a single unidirectional strip or of a plurality of parallel unidirectional strips, the heating calender, in the latter case, including a plurality of calendering grooves, and the pressure and/or a spacing between the rollers of the calender being regulated by an auxiliary system.

First claim

The invention claimed is:

1. A method of producing a pre-impregnated fibrous material comprising a fibrous material of continuous fibres and a thermoplastic polymer matrix, wherein said pre-impregnated fibrous material is produced in a plurality of parallel unidirectional ribbons, wherein the method comprises the following steps:
i) impregnating said fibrous material, in the form of several parallel rovings, said rovings not being in contact with each other, with said thermoplastic polymer or a mixture of thermoplastic polymers, in the form of a fluidised bed powder, the powder having powder particles with a mean diameter of less than 125 μm, and
ii) forming said parallel rovings of said fibrous material impregnated at step i), via calendering by means of at least one heating calender, into the form of a plurality of parallel unidirectional ribbons, said heating calender comprises a plurality of calendering grooves conforming to the number of said ribbons, the pressure and/or spacing between the rollers of said calender being regulated by a servo system.

2. The method according to claim 1 , wherein the method further comprises a step iii) of spooling said ribbons on a plurality of spools, the number of spools being identical to the number of ribbons, one spool being allocated to each ribbon.

3. The method according to claim 1 , wherein said impregnating said fibrous material in step i) is completed by a coating step of said single roving or said plurality of parallel rovings after impregnation with the powder at step i), with a molten thermoplastic polymer, wherein the polymer is the same or different from said polymer in fluidised bed powder form, said coating step being performed before said calendering in step ii).

4. The method according to claim 1 , wherein said polymer in fluidised bed powder form is a thermoplastic polymer or mixture of thermoplastic polymers.

5. The method according to claim 4 , wherein said thermoplastic polymer or mixture of thermoplastic polymers further comprises carbon fillers.

6. The method according to claim 4 , wherein the thermoplastic polymer or mixture of thermoplastic polymers comprises liquid crystal polymers or cyclic polybutylene terephthalate, or mixtures containing the liquid crystal polymers or cyclic polybutylene terephthalate, as additive.

7. The method according to claim 1 , wherein said thermoplastic polymer, or mixture of thermoplastic polymers, is selected from among amorphous polymers having a glass transition temperature Tg≥80° C. and/or from among semi-crystalline polymers having a melting temperature Tf≥150° C.

8. The method according to claim 7 , wherein the thermoplastic polymer or mixture of thermoplastic polymers is selected from among: polyaryl ether ketones; polyaryl ether ketone ketones; aromatic polyether-imides; polyaryl sulfones; polyarylsulfides; polyamides; polyacrylates; or fluorinated polymers; or mixtures thereof.

9. The method according to claim 1 , wherein said fibrous material comprises continuous fibres selected from among carbon, glass, silicon carbide, basalt, silica fibres, natural fibres, or thermoplastic fibres having a glass transition temperature Tg higher than the Tg of said polymer or a mixture of polymers when the latter are amorphous, or having a melting temperature Tf higher than the Tf of said polymer or said mixture of polymers when the latter are semi-crystalline, or a mixture of two or more of said fibres.

10. The method according to claim 1 , wherein the volume percentage of said polymer or mixture of polymers relative to said fibrous material varies from 40 to 250%.

11. The method according to claim 1 , wherein the volume percentage of said polymer or a mixture of polymers relative to said fibrous material varies from 0.2 to 15%.

12. The method according to claim 1 , wherein the calendering in step ii) is performed using a plurality of heating calenders.

13. The method according to claim 1 , wherein said heating calender(s) in step ii) comprise an integrated heating system via induction or microwave, combined with the presence of carbon fillers in said thermoplastic polymer or mixture of thermoplastic polymers.

14. The method according claim 1 , wherein said heating calender(s) in step ii) are coupled to an additional rapid heating device positioned before and/or after said calender(s).

15. A unidirectional ribbon of pre-impregnated fibrous material, wherein the ribbon is obtained using the method according to claim 1 .

16. The ribbon according to claim 15 , wherein the ribbon has a width (I) and thickness adapted for depositing by a robot for the manufacture of three-dimensional parts, without the need for slitting.

17. The use of the method according to claim 1 , for the production of calibrated ribbons adapted to the manufacture of three-dimensional composite parts via automated deposit of said ribbons by a robot.

18. The use of the ribbon of pre-impregnated fibrous material defined in claim 15 for the manufacture of three-dimensional composite parts.

19. The use according to claim 18 , wherein said manufacture of said composite parts concerns the transport sectors; renewable energies; energy storage systems; thermal protection panels; sports and leisure equipment, health and medicine; ballistics with parts for weapons or missiles; safety and electronics.

20. A three-dimensional composite part, wherein the part results from the use of at least one unidirectional ribbon of pre-impregnated fibrous material according to claim 15 .

21. A unit for implementing the method according to claim 1 , wherein the unit comprises:
a) a device for continuous impregnation of a roving or plurality of parallel rovings of fibrous material, comprising a tank of a fluidised bed of powder polymer; and
b) a device for continuous calendering of said roving or said parallel rovings, with forming into a single ribbon or into several parallel unidirectional ribbons, comprising:
b1) at least one heating calender, said calender having a calendering groove or several calendering grooves, and
b2) a system for regulating pressure and/or spacing between calender rollers.

22. The unit according to claim 21 , wherein the unit further comprises a device for spooling the ribbons of pre-impregnated fibrous materials, wherein said device for spooling comprises a number of spools identical to the number of ribbons, one spool being allocated to each ribbon.

23. The unit according to claim 21 , wherein said device for continuous impregnation, following after said fluidised bed tank, further comprises a device for coating said roving(s) of fibrous material impregnated at step i), with a molten polymer.

24. The unit according to claim 21 , wherein said heating calender(s) comprise an integrated heating system via induction.

25. The unit according to claim 21 , wherein said heating calender(s) are coupled to an additional rapid heating device, positioned before and/or after said calender(s), said rapid heating device being selected from among a microwave or induction device.

Assignees

• Arkema France

Inventors

• Gaillard Patrice
• Hochstetter Gilles
• Savart Thibaut

Classifications

• B29B15/122

  with a matrix in liquid form, e.g. as melt, solution or latex · CPC title

• B29C70/506

  and impregnating by melting a solid material, e.g. sheet, powder, fibres (B29C70/508 takes precedence) · CPC title

• B29C70/54

  Component parts, details or accessories; Auxiliary operations {, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing} · CPC title

• B29B15/105 Primary

  of reinforcement of definite length with a matrix in solid form, e.g. powder, fibre or sheet form (calendering B29C70/506) · CPC title

• B29C70/382

  Automated fiber placement [AFP] · CPC title