Moulded article reinforced with a reinforcing element, method for production thereof and use thereof
The invention relates to a method for the production of a moulded article, reinforced with at least one reinforcing element, by means of injection moulding. The reinforcing element is hereby connected integrally to the injection mould wall so that, with subsequent injection moulding of the polymer matrix, the reinforcing element is fixed in the mould. The invention relates likewise to a reinforced moulded article which is producible according to this method. The moulded articles according to the invention are used in the production of automobile parts, industrial and consumer goods and also sports appliances.
1. A method for producing a moulded article reinforced with at least one fibre ribbon, comprising:
a) impregnating an endless, flat roving with a melt of a first thermoplastic polymer to form an impregnated fibre ribbon having two opposing sides,
b) applying in regions of at least one adhesive on only one of the two opposing sides the impregnated fibre ribbon with subsequent melting of the at least one adhesive,
c) cooling and hardening of the impregnated fibre ribbon applied with the at least one adhesive,
d) heating an injection mould to a temperature which is not lower than 20 K below the melting point of the adhesive,
e) introducing the impregnated fibre ribbon from c) into the injection mould such that at least one part of the regions of the impregnated fibre ribbon coated on one side with the at least one adhesive is brought in contact with at least one temperature-controlled injection mould wall and the adhesive coated side adheres to the wall of the injection mould such that the impregnated fibre ribbon is fixed to the wall of the injection mould by the adhesive,
f) injection moulding a second thermoplastic polymer into the mould such that the second thermoplastic polymer adheres to the side of the impregnated fibre ribbon that has not been applied at least one adhesive, to obtain a reinforced moulded article, and
g) removing the reinforced moulded article from the injection mould.
2. The method according to claim 1 ,
wherein the first thermoplastic polymer is selected from the group consisting of polyamides, polyolefins, polyacrylates, polycarbonates, polysulphones, polyimides, polyesters, polyethers, polystyrenes, and mixtures thereof.
3. The method according to claim 1 ,
wherein the second thermoplastic polymer is selected from the group consisting of polyamides, polyolefins, polyacrylates, polycarbonates, polysulphones, polyimides, polyesters, polyethers, polystyrenes, and mixtures thereof.
4. The method according to claim 2 ,
wherein, in step a) and/or f), the first thermoplastic polymer and/or the second thermoplastic polymer is utilized in combination with one or more additives selected from the group consisting of inorganic stabilisers, organic stabilisers, lubricants, defoamers, chain-lengthening additives, condensation catalysts, optical brighteners, plasticisers, bonding agents, halogen-containing flame-retardants, halogen-free flame-retardants, impact modifiers, particulate fillers, dyes, pigments, and mixtures thereof.
5. The method according to claim 1 ,
wherein the at least one adhesive in step b) is applied by scattering as powder, applied as suspension, or applied by rolling on as foil or thread.
6. The method according to claim 1 ,
wherein the adhesive develops an adhesive effect only when heated to not lower than 20 K below the melting point of the adhesive.
7. The method according to claim 1 ,
wherein the at least one adhesive covers the surface of the fibre ribbon, partially or completely, at discrete points or in geometric patterns, or in areas in statistical distribution.
8. The method according to claim 1 ,
wherein the at least one adhesive is selected from the group of copolyamides and copolyesters.
9. The method according to claim 8 ,
wherein the copolyamide has a melting point, according to ISO 11357, in the range of 70° C. to 160° C., and/or a melting viscosity at 160° C. and a loading of 2.16 kg, according to ISO 1133, of 50 to 3,000 Pa*s, and/or in that the copolyester has a melting point, according to ISO 11357, in the range of 80° C. to 180° C., and/or a melting viscosity, according to ISO 1133, at 160° C. and a loading of 2.16 kg, of 50 to 1.500 Pa*s.
10. The method according to claim 1 ,
wherein the covering, layer thickness, morphology, and the adhesion capacity of the at least one adhesive is adjusted by the applied quantity of adhesive.
11. The method according to claim 1 ,
wherein reshaping of the fibre ribbon is effected before or after step b).
12. The method according to claim 1 ,
wherein, in step e), the injection mould is heated to a temperature which is not lower than 20 K below the melting temperature of the adhesive.
13. The method according to claim 1 ,
wherein, in step e), the at least one fibre ribbon is brought in contact with the at least one temperature-controlled injection mould wall by applying a pressure of 5 to 30 N/cm 2 .
14. The method according to claim 1 ,
wherein the roving consists of endless fibres, carbon-, natural-, glass-, mineral- or aramide fibres, with a flat or round cross-section of the individual filament.
15. The method according to claim 1 ,
wherein, between the impregnation step a) and application of the adhesive in step b), at least 2 fibre ribbons are joined to form a laminate in a further station and application of the adhesive is effected, in step b), on at least one side of the laminate.