Method and device for making a composite plate

1. A process for manufacturing composite sheets, comprising the steps of:

continuously depositing a web of continuous yarns on a moving substrate, the web comprising at least one first organic material and at least one reinforcing material;

depositing a powder of a second organic material on at least one surface of said web;

heating the web coated with the powder to a temperature sufficient to melt the powder into a smooth surface layer and melt said first organic material to form a matrix within which the reinforcing material is embedded;

compressing and cooling the web to form a composite strip formed of said matrix embedded with said reinforcing material and said smooth surface layer positioned on an external surface thereof; and

cutting the strip in the form of sheets or winding the strip on a rotating support.

2. The process as claimed in claim 1 , wherein the powder is selected from the group consisting of particles of a thermoplastic material and particles of a thermosetting material.

3. The process as claimed in claim 2 , wherein the thermoplastic material is selected from polyolefins, polyamides, polyesters and PVC.

4. The process as claimed in claim 2 , wherein the thermosetting material is selected from epoxies, polyesters, polyurethanes and phenolic compounds.

5. The process as claimed in claim 2 , wherein the web comprises between 20 and 90%, by weight of reinforcing material.

6. The process as claimed in claim 5 , wherein the reinforcing material is glass, carbon or aramid.

7. The process as claimed in claim 6 , wherein the web comprises at least 50% by weight of intermingled yarns of glass filaments and of filaments of a thermoplastic organic material capable of forming a matrix.

8. The process as claimed in claim 7 , wherein the web is exclusively in the form of wovens or of continuous non-interlaced yarns.

9. The process as claimed in claim 8 , wherein the powder is deposited on the web in an amount sufficient to produce a smooth surface layer with a thickness of between 0.3 and 1 mm.

10. The process as claimed in claim 1 , wherein said web includes hybrid yarns formed of thermoplastic organic filaments and glass filaments.

11. The process of claim 1 , wherein said composite strip has a width of approximately 1.5 meters.

12. A process for manufacturing composite sheets at least partly formed from intermingled yarns, comprising the steps of:

continuously depositing a web of yarns, in the form of a mat of continuous yarns, the web being formed at least partly from intermingled yarns formed of filaments of a thermoplastic organic material and glass filaments intimately mixed;

depositing on at least one side of said web a powder of an organic material having a film-forming capability in an amount sufficient to form a smooth surface under the action of heat;

heating the web coated with the powder to a temperature high enough to convert the web of yarns into a matrix within which the glass filaments are embedded and to melt the powder into a topcoat having a smooth surface; and

compressing and cooling the web to form a composite strip.

13. The process of claim 12 , wherein the powder of an organic material has an opacity sufficient to make the glass filaments in the matrix invisible.

14. The process of claim 12 , wherein the step of depositing a powder further comprises depositing a powder on both sides of said web.

15. The process of claim 12 , wherein the intermingled yarns comprise a woven material.

16. The process of claim 12 , wherein the topcoat has a thickness between 0.3-1 mm.

17. The process of claim 12 , wherein the filaments of a thermoplastic organic material and the powder of an organic material comprise the same material.

18. The process of claim 17 , wherein the filaments of a thermoplastic material and the powder of an organic material comprise polypropylene.

19. The process of claim 12 , wherein the web is compressed with a force of about 5 kN to 50 kN per meter of width.

20. The process of claim 12 , further comprising the step of preventing interpenetration of the topcoat and the matrix by introducing an intermediate layer there between.

21. A process for manufacturing composite sheets, comprising the steps of:

continuously depositing a web of continuous yarns on a moving substrate, said web comprising at least one first organic material and at least one reinforcing material;

depositing at least one intermediate structure on at least one surface of said web;

depositing a powder of a second organic material on said intermediate structure;

heating said web to a temperature sufficient to melt said powder into a smooth surface layer and melt said first organic material to form a matrix within which said reinforcing material is embedded;

compressing and cooling said web to form a composite strip; and

cutting the strip in the form of sheets or winding the strip on a rotating support.

22. The process as claimed in claim 21 , wherein said at least one intermediate structure is selected from yarns or yarn assemblies, films, veils, sheets, panels and foams.

23. The process as claimed in claim 21 , wherein said web includes hybrid yarns formed of thermoplastic organic filaments and glass filaments.