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

Abstract

The present invention relates to a process for the production of three-dimensional patterns in plastic mouldings, in particular to an injection-moulding process for the production of mouldings having a three-dimensional pattern, to the polymeric mouldings produced by means of this process, and to the use thereof, in particular for decorative purposes.

Claims

1. An injection-moulding process for the production of a polymeric moulding which has a three-dimensional pattern on at least one of its surfaces, comprising fixing a thermoplastic sheet into an injection mould which has injection mould parts A and B, which can be separated from one another and each have an inner surface A and B and together form an interior cavity, where inner surface A has protuberances and/or depressions on a base area which form a three-dimensional pattern, wherein the fixing of the thermoplastic sheet occurs to the surface A with the injection mould opened, which thermoplastic sheet is pigmented with flake-form effect pigments in an amount of 0.5 to 5% by weight, based on the total weight of the thermoplastic sheet, closing the injection mould, introducing a transparent thermoplastic melt into the interior cavity between the thermoplastic sheet and surface B of injection mould part B, heating or cooling the injection mould, and subsequently demoulding or removing the polymeric moulding, wherein the flake-form effect pigments re-orient themselves along the three-dimensional pattern and thus replicate the three-dimensional pattern of surface A on the polymeric moulding, and wherein the process is carried out at least at a temperature which is at or above the glass transition temperature T.sub.G of the thermoplastic sheet.

2. A process according to claim 1, wherein the three-dimensional pattern is a macroscopic pattern in the form of a figure, an alphanumeric motif, a line and/or dot pattern, a logo, a code or a design.

3. A process according to claim 1, wherein the flake-form effect pigments are pearlescent pigments, interference pigments, metal-effect pigments, flake-form functional pigments, flake-form structured pigments, or a mixture thereof.

4. A 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.

5. A process according to claim 1, wherein the flake-form effect pigments contain 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.

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

7. A process according to claim 1, wherein in the polymeric moulding, the thermoplastic sheet is mass-coloured with flake-form effect pigments.

8. A process according to claim 1, wherein in the polymeric moulding, an adhesion-promoting layer is located between the transparent thermoplastic and the thermoplastic sheet.

9. A process according to claim 1, wherein in the polymeric moulding, the three-dimensional pattern on surface A is a motif negative and surface A having the three-dimensional pattern represents the back of the moulding.

10. A process according to claim 1, wherein the polymeric moulding has at least one additional layer on surface A.

11. A process according to claim 1, wherein the polymeric moulding is contained in a durable good as a decorative and/or functional element.

12. A process according to claim 1, wherein the durable good is selected from the group consisting of packaging, products from the electrical and electronics industry, domestic appliances, furniture, clothing, bags, shoes, sports articles and vehicles.

13. A process according to claim 1, further comprising providing an adhesion-promoting layer on top of the thermoplastic sheet prior to introducing the transparent thermoplastic melt.

14. A process according to claim 1, wherein the thermoplastic sheet is coated with flake-form effect pigments on its entire area.

15. A process according to claim 1, wherein the thermoplastic sheet is mass-coloured with flake-form effect pigments.

16. A process according to claim 1, wherein the amount of the pigmented with flake-form effect pigments is 0.5 to 1% by weight, based on the total weight of the thermoplastic sheet.

17. A process according to claim 1, wherein the amount of the pigmented with flake-form effect pigments is 1 to 5% by weight, based on the total weight of the thermoplastic sheet.

18. An injection-moulding process for the production of a polymeric moulding which has a three-dimensional pattern on at least one of its surfaces, comprising providing an injection mould which has injection mould parts A and B, which can be separated from one another and each have an inner surface A and B and together form an interior cavity, where inner surface A has protuberances and/or depressions on a base area which form a three-dimensional pattern, and where, with the injection mould opened, fixing a thermoplastic sheet which is pigmented with flake-form effect pigments in an amount of 0.5 to 5% by weight, based on the total weight of the thermoplastic sheet, to the surface A, wherein the thermoplastic sheet is mass-coloured with flake-form effect pigments, closing the injection mould, introducing a transparent thermoplastic melt into the interior cavity between the thermoplastic sheet and surface B of injection mould part B, heating or cooling the injection mould, and subsequently demoulding or removing the polymeric moulding, wherein the flake-form effect pigments re-orient themselves along the three-dimensional pattern and thus replicate the three-dimensional pattern of surface A on the polymeric moulding, and wherein the process is carried out at least at a temperature which is at or above the glass transition temperature T.sub.G of the thermoplastic sheet.

19. An injection-moulding process for the production of a polymeric moulding which has a three-dimensional pattern on at least one of its surfaces, which process is performed in an injection mould which has injection mould parts A and B, which can be separated from one another and each have an inner surface A and B and together form an interior cavity, where inner surface A has protuberances and/or depressions on a base area which form a three-dimensional pattern, said process comprising fixing a thermoplastic sheet, which is pigmented with flake-form effect pigments in an amount of 0.5to 5% by weight, based on the total weight of the thermoplastic sheet, to the surface A before introduction of a transparent thermoplastic melt into the interior cavity between the thermoplastic sheet and surface B of injection mould part B, wherein the flake-form effect pigments re-orient themselves along the three-dimensional pattern and thus replicate the three-dimensional pattern of surface A on the polymeric moulding, and wherein the process is carried out at least at a temperature which is at or above the glass transition temperature T.sub.G of the thermoplastic sheet.

Description

EXAMPLE 1

(1) An ABS sheet having a content of 0.5% by weight of COLORSTREAM Autumn Mystery (flake-form effect pigment based on SiO.sub.2 substrates, particle size 5-50 , product from Merck KGaA) and 0.05% by weight of PV True Blue A2R (product from Clariant International Ltd.) having a thickness of about 400 m is cut to a size of 100150 mm and spot-fixed via adhesive spots to the inner surface of the mould insert of an injection mould part (ejector side) which has a three-dimensional raised object as pattern.

(2) An injection-moulding machine of the Kraus-Maffei CX-130-380 type is used. 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 sheet and the surface of the injection mould not provided with the sheet (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).

(3) After the cooling operation and the opening of the injection mould, a plastic plate is obtained whose first surface has an intensely coloured, uniformly glossy surface of varying colour with a three-dimensional pattern located therein which corresponds to the negative motif of the three-dimensional pattern located in the injection mould and whose other surface is flat and is formed from a transparent, colourless plastic. Observed from the side of the transparent plastic surface, the three-dimensional pattern of the other surface appears as positive pattern with high gloss and with particular optical depth and imparts the impression of a three-dimensional object behind glass.

EXAMPLE 2

(4) Example 1 is repeated, with the modification that a polystyrene sheet is employed which is pigmented with 1% by weight of IRIODIN 305 Solar Gold (flake-form effect pigment based on mica, particle size 10-60 m, product from Merck KGaA). All other parameters remain unchanged. A plastic plate is obtained which has on one surface a surface layer which has a strongly golden gloss and is provided with a three-dimensional pattern. Observed from the opposite surface of the plastic plate, the negative image of the three-dimensional pattern appears with a strong gloss with deep-golden colour, uniform gloss and high depth effect.

(5) The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

(6) From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.