Process for the production of virtual three-dimensional patterns in mouldings

Abstract

The present invention relates to a process for the production of virtual three-dimensional patterns in mouldings, in particular to an injection-moulding process for the production of mouldings having a virtual three-dimensional pattern which is formed by flake-form effect pigments, to the mouldings produced by means of this process, and to the use thereof, in particular for decorative purposes.

Claims

1. Injection-moulding process for the production of virtual three-dimensional patterns in mouldings, comprising: providing an injection mould which has injection mould parts A and B which can be separated from one another and which in each case have an inside surface A and B and together form an internal cavity, and where, with the injection mould opened, a preform which has a two- or three-dimensional shape and an outside surface which is fixed to the inside surface A of injection mould part A in such a way as to occupy part of the cavity where the outside surface of the preform not fixed to the inside surface A of injection mould part A faces the part of the cavity not occupied by the preform when the mould is opened, where this outside surface facing the cavity has, at least on a part-area thereof, bumps and/or pits which together form a three-dimensional pattern, introducing a thermoplastic film which has been mass-coloured with flake-form effect pigments into the internal cavity, closing the injection mould, introducing a transparent thermoplastic melt into the internal cavity between the thermoplastic film and the surface B of injection mould part B, where the thermoplastic film is three-dimensionally deformed and forms a strongly adherent and positive connection to at least that part-area of the outside surface of the preform that contains the three-dimensional pattern and at the same time to the thermoplastic melt, where the flake-form effect pigments reorient with their longitudinal axes at the bumps and/or pits and replicate and optically intensify the three-dimensional pattern located on the outside surface of the preform on or in the thermoplastic film, heating or cooling the injection mould and, subsequently, demoulding or removing the resultant moulding, which has an outside surface of a transparent thermoplastic and exhibits on at least part of this outside surface a virtual three-dimensional pattern formed by the flake-form effect pigments.

2. Process according to claim 1, wherein the thermoplastic melt, when injected, has at least a temperature which is at or above the glass transition temperature T.sub.G of the thermoplastic film.

3. Process according to claim 1, wherein the three-dimensional pattern is a macroscopic pattern in the form of a pictorial object, an alphanumeric motif, a line and/or dot pattern, a logo or a code.

4. Process according to claim 1, wherein the flake-form effect pigments are selected from the group consisting of pearlescent pigments, interference pigments, metal-effect pigments, flake-form functional pigments, flake-form structured pigments, or a mixture thereof.

5. Process according to claim 1, wherein the flake-form effect pigments have a particle size in the range from 5 to 250 m and an aspect ratio of at least 2.

6. Process according to claim 1, wherein the flake-form effect pigments consist of a flake-form substrate and one or more layers on the substrate, where the substrate and the layer located directly on the substrate and/or at least two layers which are in each case adjacent differ from one another in their refractive indices n at least by n=0.1.

7. Process according to claim 1, wherein the flake-form effect pigments are present in the pigmented thermoplastic film in an amount of 0.1 to 20% by weight, based on the total weight of the pigmented film.

8. Process according to claim 1, wherein the pigmented thermoplastic film, in addition to the flake-form effect pigments, also comprises further organic or inorganic coloured pigments, dyes and/or fillers.

Description

EXAMPLE 1

(1) In a prior process step, a plastic plate is injection-moulded from ABS (Terluran GP-22, product from BASF SE) having a carbon-black content of 0.2% by weight, based on the weight of the plastic, in a size of 100150 mm and a thickness of 10 mm. One of the principal surfaces of the plastic plate is provided with a logo in a size of about 3045 mm by laser ablation with the aid of a laser device (Trumpf, Vectormark compact). The logo has various pits, each with a depth of about 100-150 m.

(2) A film produced by means of an injection-moulding process (SAN Luran 358N, product from BASF SE) having a content of 1.5% by weight of Colorstream T10-09 Pacific Twinkle (flake-form effect pigment based on SiO.sub.2 substrates, particle size 20-200 m, product from Merck KGaA) and 0.2% by weight of PV Fast Blue B2G01 (product from Clariant International Ltd.) having a thickness of about 800 m is produced in a size of 100150 mm.

(3) An injection-moulding machine of the Kraus-Maffei CX-130-380 type is used. The prefabricated plastic plate is laid in a mould insert measuring 100150 mm in the inside surface of the injection mould in such a way that the surface of the plastic plate that carries the logo faces the cavity of the injection mould. The film mass-coloured with effect pigments, which has likewise been produced in advance, is subsequently fixed in the internal cavity of the injection mould, and the mould is closed.

(4) After closing of the mould, a transparent plastic melt (SAN Luran 358 N, product from BASF SE) is injected into the cavity remaining in the injection mould between the pigmented thermoplastic film and the surface of the injection mould that is not provided with the preform (nozzle side). The injection operation is carried out at a temperature in the range from 220 to 260 C. and a pressure in the range from 450 to 900 bar (4.510.sup.7 N/m.sup.2 to 910.sup.7 N/m.sup.2).

(5) After the cooling operation and the opening of the injection mould, a plastic plate is obtained whose first outside surface exhibits an area with uniformly strong blue gloss which changes colour between blue and green and gives the impression of lying behind glass, having a glossy, virtual three-dimensional pattern located therein in the form of a logo which is formed by the flake-form effect pigments in the film and which corresponds to the motif of the logo on the surface of the prefabricated plastic plate containing carbon black. The other principal surface of the plastic plate obtained is flat, opaque and has a black colour.

EXAMPLE 2

(6) A PP preform in the outer shape of a closure cap having an outside diameter of 47 mm, a height of 11.5 mm and a wall thickness of 0.6 mm (Metocene HM 648T, product from LyondellBasell, NL) having a carbon black content of 0.2%, based on the weight of the plastic, is injection-moulded in a prior process step. The closure cap has a three-dimensional zigzag structure with a diameter of about 30 mm on its outside surface (lid).

(7) A pigmented film having a thickness of 400 m (Metocene HM 648T, product from LyondellBasell, NL) which has a content of 2% by weight of a flake-form effect pigment (Iriodin 4504, particle size 5-50 m, product from Merck KGaA) is produced by means of an extrusion process. The film is cut to give a circle having a diameter of 44 mm.

(8) An injection-moulding machine of the Arburg Allrounder 320 M type is used. The preform is laid in a mould insert (outside diameter 48.2 mm) in the inside surface of the injection mould in such a way that the surface of the preform carrying the contour faces the cavity of the injection mould. The film mass-coloured with effect pigments, which has likewise been produced in advance, is subsequently fixed in the internal cavity of the mould, and the mould is closed.

(9) After closing of the mould, a transparent plastic melt (PP, Borealis PP RJ901MO) is injected into the injection mould cavity remaining between the pigmented thermoplastic film and the surface of the injection mould that has not been provided with the preform (nozzle side). The injection operation is carried out at a temperature in the range from 180 to 260 C. and a pressure in the range from 300 to 900 bar.

(10) After the cooling operation and the opening of the injection mould, a closure cap is obtained whose outside surface exhibits, in the region of the lid, an area with uniform gloss which changes in colour and gives the impression of lying behind glass, having a glossy, virtual three-dimensional pattern located therein in the form of a zigzag structure which is formed by the flake-form effect pigments in the film and which corresponds in shape to the motif of the pattern on the surface of the prefabricated preform, but which gives a significantly more three-dimensional impression in optical depth and thus the spatial impression imparted than the actual three-dimensional pattern on the surface of the preform. The inside surface of the closure cap obtained is flat, opaque and has a black colour.