METHOD FOR THE MANUFACTURE OF POST-DEFORMABLE HIGH- PRESSURE COMPOSITE AND PRODUCT OBTAINED THEREFROM

Abstract

The present invention falls within the scope of thermo-laminated and compact high-pressure composites, namely it relates to a method for the manufacture of a post-deformable high-pressure composite, which can be used in the automotive, aircraft, railway and naval industries, as well as in the architecture and design sector, both in indoor and outdoor environments, comprising the steps of formation of a composite (1) by the arrangement of at least two layers of material, including a layer of Kraft paper sheets (3) coated with thermoplastic resin and a layer of decorative coating; the composite formed in a flat shape, when subjected to a certain temperature and pressure in a mould (4), changes in its geometry according to the shape of that mould (4). It is also an object of this invention the product obtained with the aforementioned manufacturing method.

Claims

1. A method for the manufacture of a post-deformable high-pressure composite, characterized in that it comprises the following steps: a) formation of a composite (1) by the arrangement of at least two layers of material, among which: i. a plurality of Kraft paper sheets (3) coated with at least one type of thermoplastic resin, forming a laminate with two opposite flat surfaces; and ii. a decorative coating (2) arranged on at least one of the flat surfaces of the laminate, the said decorative coating (2) being impregnated with at least one thermosetting resin or at least one thermoplastic resin; b) hot compression moulding of the composite (1) formed in step a) by means of compression moulding at a temperature between 120° C. and 200° C. and at a pressure between 50 and 120 bar for 5 to 25 minutes; c) the composite (1) formed in step b) remains in the compression moulding means until the latter cool to a temperature ranging from 17 to 22° C. and at a pressure between 50 and 120 bar.

2. Manufacturing method according to claim 1, where in the composite (1) formed in step a) is subjected to a pre-moulding by placing the laminate on the compression moulding means at a pressure between 10 and 40 bar until a temperature between 120° C. and 200° C. is reached.

3. Manufacturing method according to claim 2, where in the moulding means are a plate press.

4. Manufacturing method according to claim 1, where in after step (i), synthetic fibres are additionally laid on at least one side of the laminate in a proportion between 5 and 20% of the total weight of the laminate.

5. Manufacturing method according to the claim 4, where in the synthetic fibres are glass, basalt and/or carbon fibres with a surface unit of about 150 g/m.sup.2.

6. Manufacturing method according to claim 1, where in the Kraft paper sheets undergo a surface treatment with cold plasma produced by dielectric-barrier discharge at atmospheric pressure.

7. Manufacturing method according to claim 1, where in the Kraft paper sheets undergo a pre-treatment with alkaline solutions with a concentration between 1 and 3% of sodium hydroxide.

8. Manufacturing method according to claim 1, where in the Kraft paper sheets have a grammage between 150 and 250 g/m.sup.2, a porosity of less than 14 seconds in Gurley porosity and a maximum tensile strain of more than 15 N/(g.Math.m).

9. Manufacturing method according to claim 1, where in the thermoplastic resin has a fluidity index between 5 and 8, preferably 6, a processing temperature ranging from 120° C. to 200° C. and a density between 0.7 and 1.3 g/m.sup.3.

10. Manufacturing method according to claim 9, where in the Kraft paper sheets are coated with thermoplastic resin in a proportion of 25-35% resin to 65-75% Kraft paper.

11. Manufacturing method according to claim 10, where in the thermoplastic resin is selected among polypropylene, polyamide and polyethylene resins.

12. Manufacturing method according to claim 1, where in the thermoplastic resin is in the form of a film, the coating of the Kraft paper sheets (3) being made by intercalating Kraft paper sheets (3) with thermoplastic films.

13. Manufacturing method according to claim 1, where in after step c), once the composite has cooled and stabilized, it can be thermoformed to create the shape through a mould (4) at a temperature between 100 and 130° C. and at a pressure between 2 and 40 bar.

14. Manufacturing method according to any of the claim 1, where in the decorative coating is a decorative paper.

15. Manufacturing method according to any of the claim 1, where in the decorative coating is a woven-type coating.

16. A product obtained by means of the manufacturing method disclosed in claim 1, where in it has a resistance to impact higher than 5000000000 Pa, a bending strength higher than 5000 J/m.sup.2 and a density lower than 1.45 g/m.sup.3.

Description

DESCRIPTION OF THE FIGURES

[0035] FIG. 1—schematic general representation of the process in the thermoforming step of the post-deformable composite (1) through a mould (4), the composite (1) comprising a decorative coating (2), a plurality of Kraft paper sheets (3) coated with thermoplastic resin.

DETAILED DESCRIPTION OF THE INVENTION

[0036] The general configurations of this invention are described in the Summary of the Invention. Those configurations are detailed below, according to other advantageous and/or alternative embodiments of the present invention.

[0037] Synthetic fibres can be selected from glass, basalt and/or carbon fibres, with a surface unit of about 150 g/m.sup.2.

[0038] Kraft paper sheets (3) have a porosity of less than 14 seconds in Gurley porosity and a maximum tensile strain of more than 15 N/(g.Math.m). The porosity of the selected Kraft paper (3) is high comparatively to other Kraft papers (3) in order to allow the thermoplastic resin to penetrate in the paper pores and integrate therein. On the other hand, it is also a paper with high mechanical resistance so as to bear the resin load without tearing and, thus, guaranteeing that the composite (1) is given an overall mechanical resistance.

[0039] Thermoplastic resins can be selected among polypropylene, polyamide and polyethylene-type resins. Depending on the application of the final product, the preferred resins are polyethylene and polyamide. The polyethylene resin gives a higher resistance to impact and a lower density to the composite (1), i.e. lighter composite(s) (1). On the other hand, polyamide resin provides greater bending strength and therefore a more robust composite (1).

[0040] In addition to these selection factors, the way in which the thermoplastic resin is supplied is also essential for the implementation of the invention as it influences the efficiency of impregnation. Thermoplastic resin is supplied in powder, film, paste or non-woven form. Thus, the way in which the Kraft sheets (3) are coated will depend on how the thermoplastic resin is supplied.

[0041] In a preferred embodiment of this invention, the thermoplastic resin is in the form of a film, the coating of the Kraft paper sheets (3) being made by intercalating Kraft paper sheets (3) with thermoplastic films. The manufacture of the composite (1) is made easier and faster with the resin supplied in film or non-woven forms, since the compression moulding process itself promotes the integration of the resin into the paper by causing it to penetrate the paper pores due to the pressure of the compression means and under the action of heat.

[0042] The thickness of the post-deformable composite (1) obtained may vary between 0.8 and 30 mm, depending on the grammage of the Kraft paper (3) and the number of Kraft paper (3) sheets used. It should be noted that post-deformable composites (1) with a thickness between 0.8 and mm are known as thin laminated composites, while composites (1) whose thickness is between 2 mm and 30 mm are referred to as compact composites.

[0043] The final product obtained from the process described above, i.e. the post-deformable high-pressure composite (1) has a resistance to impact higher than 5000000000 Pa, a bending strength higher than 5000 J/m2 and a density lower than 1.45 g/m.sup.3.

[0044] Surface resistance (scratch, abrasion, water vapour, impact and chemicals) must comply with the standards which are applicable to the conventional high-pressure laminates and compacts.

[0045] Dimensional stability, stability in wet environments or outdoor environments, must comply with the standards applicable to the conventional high-pressure laminates and compacts.