Liquid composition for applications of SMC-moulded thermoplastic composites

1. A process for manufacturing a preimpregnated fibrous material, the process comprising impregnating a fibrous reinforcement with a liquid composition, the liquid composition including:

a) a (meth)acrylic polymer,

b) a (meth)acrylic monomer, and

c) a maturation agent selected from a metal oxide or a metal hydroxide, said (meth)acrylic polymer comprising a monomer which carries a carboxylic acid function, and

said liquid composition having a dynamic viscosity of between 10 mPa·s and 10 000 mPa·s at 25° C.

2. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , wherein the fibrous reinforcement is composed of short fibers having a length of between 3 mm and 100 mm.

3. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , wherein the fibrous reinforcement is composed of long fibers, said long fibers having an aspect ratio of at least 1000.

4. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , wherein the fibrous reinforcement is composed of a mixture of short fibers and long fibers.

5. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , wherein the impregnation takes place continuously.

6. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , comprising a calendering step.

7. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , comprising a maturation step.

8. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , comprising a step of maturing the liquid composition at a temperature of between 10° C. and 100° C. for a time of 120 hours or less.

9. The process for manufacturing a preimpregnated fibrous material as claimed in claim 7 , wherein the viscosity of the liquid composition increases during the maturation step to reach a plateau or pseudoplateau.

10. The process for manufacturing a preimpregnated fibrous material as claimed in claim 7 , wherein the viscosity of the liquid composition increases during the maturation step to reach a plateau or pseudoplateau, with a relative increase in viscosity of less than +0.5%/min.

11. A preimpregnated fibrous material comprising the liquid composition as claimed in claim 1 .

12. A process for manufacturing a composite material part from a preimpregnated fibrous material as claimed in claim 11 , comprising:

shaping the preimpregnated fibrous material, and

polymerizing the liquid composition impregnating said fibrous reinforcement.

13. The process for manufacturing a composite material part as claimed in claim 12 , wherein the shaping step is a molding step.

14. The process for manufacturing a composite material part as claimed in claim 13 , wherein the molding step is carried out under pressure and at a temperature of between 50° C. and 200° C.

15. The process for manufacturing a composite material part as claimed in claim 12 , comprising an additional postforming step.

16. The process for manufacturing a composite material part as claimed in claim 12 , comprising an additional welding or gluing or laminating step.

17. A composite material part obtained by the manufacturing process as claimed in claim 12 .

18. The composite material part as claimed in claim 17 , said part being a motor vehicle part, a boat part, a train part, a sports article, an airplane or helicopter part, a spaceship or rocket part, a photovoltaic module part, a material for construction or building, a wind turbine part, a furniture part, a construction or building part, a telephone or cellphone part, a computer or television part, or a printer or photocopier part.

19. The composite material part as claimed in claim 17 , wherein said part is a structural or semistructural part of a vehicle.

20. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , wherein the maturation agent is selected from the group consisting of MgO, Mg(OH) 2 , CaO, Ca(OH) 2 or ZnO.

21. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , wherein the liquid composition comprises:

a) from 10% by weight to 60% by weight of (meth)acrylic polymer,

b) from 40% by weight to 90% by weight of (meth)acrylic monomer, including at least 0.1% by weight of a (meth)acrylic monomer carrying a carboxylic acid function, and

c) from 0.5 phr to 10 phr of maturation agent.

22. The process for manufacturing a preimpregnated fibrous material as claimed in claim 1 , wherein the liquid composition comprises:

a) from 10% by weight to 60% by weight of a (meth)acrylic polymer, said (meth)acrylic polymer comprising at least 1% by weight of a monomer which carries a carboxylic acid function,

b) from 40% by weight to 90% by weight of (meth)acrylic monomer, and

c) from 0.5 phr to 10 phr by weight of maturation agent.