FR2801530A1 - Decorative sheet material, used for e.g. for motor vehicle trim has decorative layer, comprises decorative layer, polymer connecting layer and transparent polymer protective layer - Google Patents

Abstract

Decorative sheet material (1) comprises (a) at least one decorative layer (2); (b) a polymer-based connecting layer (3) for attaching the material to a supporting surface; and (c) a thermoplastic protective layer (5) containing optional metal fibres over the decorative layer. The connecting layer (3) is polyolefin-based, grafted with a compatibility grouping. An Independent claim is also included for the production of the decorative sheet comprising coextruxion and rolling.

Description

The present invention relates to a method of manufacturing parts having an external decoration. Such a process, for example, usable in the field of the automobile industry for producing bumpers, wheel trims, body belts, grille trims, mirror caps, etc.

In general, consumers expect parts that make up an article to be reliable and have an aesthetic and durable appearance.

Metal parts are thus widely distributed in the industry because of their solidity and their metallic appearance which is noble and resistant.

However, plastic parts are essential at the expense of metal parts because of the low cost of plastic, its possibilities of implementation suitable for large series, its light tee ...

The final appearance of these plastic parts is generally obtained by a painting operation. However, this technique requires a prior cleaning of the parts and a subsequent treatment of them to improve the resistance of the paint layer. In addition, difficulties in adhesion of paint to certain plastics such as polypropylene are frequently encountered. This increases the cost price of these parts.

It is also known processes for coloring the plastic material in the mass. The aspect obtained is therefore not very rewarding and resists badly to external aggressions or to the cost of using expensive materials. Furthermore, it is not possible to obtain colored parts with glitter by ection because the flux lines and the weld lines are unfavorable to the general appearance of these parts.

Another technique consists in decorating the pieces by screen printing or heliography but these techniques are limited to pieces of small dimensions and decorations obtained are very fragile.

There is therefore an unresolved need conveniently to date for parts having a durable and resistant external decoration.

For this purpose, provision is made, according to the invention, for a method of manufacturing parts having a decorative surface comprising the steps of - preparing by extrusion a film comprising at least one polyamide layer associated with a layer of thermoplastic material having properties bonding with a specific thermoplastic material injection, - placing the film in a mold, layer having bonding properties extending inside the mold relative to the polyamide layer - and injecting the determined thermoplastic material into the mold which forms the body of the piece. Thus, the decorative surface of the piece is that of the visible surface of the polyamide layer which has good resistance to external aggressions and in particular to scratches. In addition, it is easily possible to obtain effects by treating the polyamide layer in a corresponding manner (screen printing, rotogravure printing, etc.), preferably on its face in contact with the layer having binding properties.

Other characteristics and advantages vention will appear more clearly in the light of the following description of a particular nonlimiting embodiment of the invention.

Reference will be made to the accompanying drawings, among which - FIG. 1 is a sectional view in the thickness of a film for implementing the method according to the invention, - FIG. 2 is a view similar to FIG. 1 a film integral with a plate intended for example for thermoforming, With reference to the figures, the method of manufacturing parts according to the invention consists in producing a part having a decorative surface from a film 1 comprising a polyamide layer 2 and a bonding layer 3.

The layer 3 here has bonding properties with the thermoplastic material forms the part. This bonding material will for example be a polyamide / polyolefin blend if the part structure is a polyolefin.

The film 1 is produced by coextrusion of the two layers 2 and 3.

This film can be placed in an injection mold of the part, against a wall thereof. The injected material then comes into contact with the layer 3 to which it binds. The piece is thus covered with a skin having the desired decorative surface.

Alternatively as shown in Figure 2, the film of Figure 1 can be attached to the face 4a of a plate 4 to form a blank part then intended to be thermoformed. The association of the film with the plate can be carried out by injecting the plate into a mold, one face of which would be provided with the film.

Note that the polyamide layer 1 can be provided on its face with .-, 'contact with the binding material of a decorative pattern produced by any printing means.

 The polyamide being produced in a transparent manner lets see this pattern which is protected from external aggressions.

Claims (2)

1. Method of manufacturing parts having decorative surface, characterized in that it comprises the steps - of preparing by extrusion a film (1) comprising at least one layer (2) of polyamide associated with a layer (3) of thermoplastic material , having bonding properties with a determined thermoplastic injection material, placing the film (1) in a mold, layer having bonding properties extending from an inner side to the mold relative to the polyamide layer, - and injecting into the mold the determined thermoplastic material which forms the part body (4). 2. Method according to claim 1, characterized in that the body of the part being a plate, it comprises an additional step of thermoforming.