Aqueous impregnation bath for reinforcement fibres and uses thereof
The invention relates to an aqueous impregnation bath for reinforcement fibers for manufacturing prepregs having a thermoplastic matrix, resulting in highly satisfactory consolidation, in terms of residual porosity, of the composite material parts manufactured using the prepregs. The impregnation bath includes a least one thermoplastic polymer, a surfactant and water, and is characterized in that the surfactant is an ethoxylated stearyl alcohol of formula: HO—(CH 2 —CH 2 —O) n —CH 2 —(CH 2 ) 16 —CH 3 wherein n is 100. The invention also relates to a method for impregnating reinforcement fibers using the impregnation bath, to a method for manufacturing a prepreg having a thermoplastic matrix using the impregnation method, and to a method for manufacturing a part made of a composite material having a thermoplastic matrix using the method for manufacturing a prepreg. The invention is useful in any field for manufacturing parts made of composite materials and, specifically, in the aeronautical, space, rail, shipping and automotive industries.
1. An impregnation bath for reinforcement fibres for a manufacture of a prepreg having a thermoplastic matrix, comprising at least one thermoplastic polymer, a surfactant and water, wherein the surfactant is an ethoxylated stearyl alcohol of formula: HO—(CH 2 —CH 2 —O) n —CH 2 —(CH 2 ) 16 —CH 3 wherein n is 100.
2. The impregnation bath of claim 1 , which comprises from 0.25% to 5% by weight of the surfactant with respect to the thermoplastic polymer.
3. The impregnation bath of claim 1 , which comprises from 10% to 50% by weight of the thermoplastic polymer with respect to water.
4. The impregnation bath of claim 1 , wherein the thermoplastic polymer is a polyaryletherketone, a polyethyleneimine, a polyolefin, a polyamide, a polyimide, a thermoplastic polyurethane, a polyphenylene sulphide, a polyethylene terephthalate, a polybutylene terephthalate, a polysulphone, a polycarbonate, a polyvinyl chloride or a polyvinyl alcohol.
5. The impregnation bath of claim 4 , wherein the thermoplastic polymer is a polyetheretherketone.
6. The impregnation bath of claim 1 , wherein the thermoplastic polymer is in a micronized form.
7. A method for impregnating reinforcement fibres for a manufacture of a prepreg having a thermoplastic matrix, comprising an immersion of the reinforcement fibres in an impregnation bath comprising at least one thermoplastic polymer, a surfactant and water, wherein the surfactant is an ethoxylated stearyl alcohol of formula: HO—(CH 2 —CH 2 —O) n —CH 2 —(CH 2 ) 16 —CH 3 wherein n is 100.
8. The method of claim 7 , wherein the reinforcement fibres are glass fibres, carbon fibres, graphite fibres, silica fibres, metal fibres, ceramic fibres, synthetic organic fibres or natural organic fibres.
9. The method of claim 7 , wherein the reinforcement fibres are carbon fibres and the impregnation bath comprises from 35% to 75% by weight of immersed reinforcement fibres with respect to the total weight of the reinforcement fibres and the thermoplastic polymer.
10. The method of claim 7 , wherein the reinforcement fibres are glass or silica fibres and the impregnation bath comprises from 45% to 82% by weight of immersed reinforcement fibres with respect to the total weight of the reinforcement fibres and the thermoplastic polymer.
11. A method for manufacturing a prepreg having a thermoplastic matrix, comprising a step of impregnating reinforcement fibres, the impregnating step comprising an immersion of the reinforcement fibres in an impregnation bath comprising at least one thermoplastic polymer, a surfactant and water, wherein the surfactant is an ethoxylated stearyl alcohol of formula: HO—(CH 2 —CH 2 —O) n —CH 2 —(CH 2 ) 16 —CH 3 wherein n is 100.
12. A method for manufacturing a part made of a composite material having a thermoplastic matrix, comprising a step of impregnating reinforcement fibres, the impregnating step comprising an immersion of the reinforcement fibres in an impregnation bath comprising at least one thermoplastic polymer, a surfactant and water, wherein the surfactant is an ethoxylated stearyl alcohol of formula: HO—(CH 2 —CH 2 —O) n —CH 2 —(CH 2 ) 16 —CH 3 wherein n is 100.
13. The method of claim 11 , further comprising:
a step of drying the impregnated reinforcement fibres,
a step of heating the dried reinforcement fibres to a temperature above the melting temperature of the thermoplastic polymer, and
a step of calendering the heated reinforcement fibres.