Method for manufacturing a multi-layered moulded synthetic part and thus obtained part
The invention relates to a method for manufacturing a multi-layered moulded synthetic part comprising a preformed elastomeric moulded skin ( 5 ), a moulded carrier ( 8 ) of a thermoplastic material and optionally an intermediate foam layer ( 6 ). In this method, the elastomeric skin ( 5 ) is moulded in a first step and the thermoplastic material for the carrier ( 8 ) is subsequently moulded in molten state to the back of said moulded skin ( 5 ). According to the invention, the moulded skin is made of a thermosetting synthetic material. Compared to a thermoplastic skin, such a thermosetting skin is less subjected to visible defects, in particular in case it has been provided with a superficial texture such as a leather grain, when the thermoplastic carrier is moulded thereto. Moulding of the thermoplastic carrier can be done by an injection moulding, an injection pressure moulding or a low pressure moulding technique.
1. A method for manufacturing a multi-layered moulded synthetic part comprising at least a preformed elastomeric moulded skin and a moulded carrier of a thermoplastic material, which method comprises the steps of:
a) moulding said preformed elastomeric moulded skin,
b) melting the thermoplastic material for the carrier, and
c) applying the molten thermoplastic material in a mould containing the preformed elastomeric moulded skin and moulding said thermoplastic material in said mould, in molten state, to the back of said moulded skin, the carrier being moulded to the back of the skin according to an injection moulding process wherein the molten thermoplastic material is injected in molten state in said mould after said mould has been closed so that the injected molten thermoplastic material exerts a pressure higher than 350 kg/cm 2 on the moulded skin,
characterized in that said moulded skin is made of a thermosetting polyurethane material.
2. A method according to claim 1 , characterized in that said preformed skin is made by a spray, a RIM or a slush moulding process starting from a reaction mixture which is allowed to cure to produce the preformed skin.
3. A method according to claim 1 , characterized in that, before moulding the thermoplastic material for the carrier to the back of the skin, a foam backing layer is applied against the back of the skin.
4. A method according to claim 3 , characterized in that said foam backing layer is sprayed against the skin or is applied thereto in a mould according to a RIM process.
5. A method according to claim 1 , characterized in that said skin is mouleded against a mould surface which is either situated in the mould wherein the thermoplastic carrier is moulded or which is transferred thereto after having moulded the skin on this mould surface.
6. A method according to claim 1 , characterized in that said skin is moulded against a first mould surface and is transferred from this first mould surface to a mould surface of the mould wherein the thermoplastic carrier is moulded.
7. method according to claim 6 , characterized in that the mould surface of the mould to which the moulded skin is transferred shows a superficial texture which is, as a result of the pressure and heat applied to the skin during the moulding process of the thermoplastic carrier, transmitted thereto in order to produce a grained skin.
8. A method according to claim 1 , characterized in that said first mould surface shows a superficial texture in order to produce a grained skin.
9. A method according to claim 8 , characterized in that the mould surface of the mould to which the moulded skin is transferred is free of any superficial texture.
10. A method according to claim 1 , characterized in that the thermoplastic material from which the carrier is made is selected from the group consisting of polypropylene (PP), polycarbonate (PC), acrylnitril-butadiene-styrol (ABS), ABS blends, acrylester-styrol-acrylnitril (ASA), polystyrol (PS) and thermoplastic polyurethane (TPU).
11. A method according to claim 10 , characterized in that the thermoplastic material from which the carrier is made is selected from the group consisting of polycarbonate (PC), acrylnitril-butadiene-styrol (ABS), ABS blends, acrylester-styrol-acrylnitril (ASA), polystyrol (PS) and thermoplastic polyurethane (TPU).
12. A method according to claim 11 , characterized in that the thermoplastic material from which the carrier is made is selected from the group consisting of PC, ABS and ABS blends.