TRANSFER FILM FOR TRANSFERRING COATING MATERIALS TO COMPONENTS

Abstract

The invention relates to a polymeric film for coating plastics mouldings with a coating material, the polymeric film comprising an adhesion-modified layer and also a layer of the coating material; where the polymeric film together with the adhesion-modified layer and the layer of the coating material is formable at room temperature; where the coating material wholly or partly covers the adhesion-modified layer; and where the adhesion-modified layer has a layer thickness of at least 0.1 μm; and where the adhesion-modified layer is in direct contact with the coating material. The invention further relates to uses of the polymeric film of the invention, to methods for its production and to methods for coating components using the polymeric film of the invention.

Claims

1. A polymeric film for coating plastics moldings with a coating material, where the polymeric film comprises an adhesion-modified layer and a layer of the coating material; where the polymeric film is formable at room temperature; where the coating material wholly or partly covers the adhesion-modified layer; where the adhesion-modified layer has a layer thickness of at least 1.0 μm, is in direct contact with the coating material, and (i) has a surface energy, on its surface side facing the coating material, of at least 27 mN/m; and (ii) is based on a mixture which comprises at least one polyolefin and at least (a) one adhesion promoter, (b) one thermoplastic elastomer or (c) one polyamide alloy.

2. The polymeric film of claim 1, where the coating material has been produced from a curable composition; and/or is in the cured state.

3. The polymeric film of claim 1, where the coating material is a varnish.

4. The polymeric film of claim 3, where the varnish is a thermosetting varnish; and/or is based on polyurethane, polyacrylate or epoxide.

5. The polymeric film of claim 1, where the coating material at 23° C. has an elongation at break of at least 100%; and/or forms one of the two outer sides of the polymeric film; and/or has a layer thickness of at least 5 μm.

6. The polymeric film of claim 1, where the surface side of the adhesion-modified layer that faces the coating material has not been surface-activated.

7. The polymeric film of claim 1, where the polymers or polymer mixtures in all layers have in each case a melting temperature of at least 110° C., determined by DSC according to DIN EN ISO 11357-3:2018-07.

8. The polymeric film of claim 1, where the adhesion-modified layer, on its surface side facing the coating material, has a surface energy of at most 45 mN/m.

9. The polymeric film of claim 1, where the adhesion-modified layer is based on a mixture which comprises at least one polyolefin and at least one adhesion promoter, where (i) the adhesion promoter is selected from acid anhydride-modified polyolefins, hydroxyl-modified polyolefins, acid-modified polyolefins, acetate-modified polyolefins and epoxy-modified polyolefins; and/or (ii) the weight fraction of the adhesion promoter is in the range from 10 wt % to 65 wt %, based on the total weight of the adhesion-modified layer; and/or (iii) the at least one polyolefin is selected from the group consisting of polyethylene homopolymer, polyethylene copolymer, polypropylene homopolymer and polypropylene copolymer.

10. The polymeric film of claim 1, where the adhesion-modified layer is based on a mixture which comprises at least one polyolefin and at least one thermoplastic elastomer, where (i) the thermoplastic elastomer is selected from thermoplastic copolyesters elastomers, thermoplastic polyamide elastomers and thermoplastic polyurethane elastomers; and/or (ii) the weight fraction of the thermoplastic elastomer is in the range from 1.0 wt % to 35 wt %, based on the total weight of the adhesion-modified layer; and/or (iii) the at least one polyolefin is selected from the group consisting of polyethylene homopolymer, polyethylene copolymer, polypropylene homopolymer and polypropylene copolymer.

11. The polymeric film of claim 10, where the adhesion-modified layer further comprises at least one compatibilizer, where (i) the compatibilizer is selected from ethylene-acrylate copolymers, MAH grafted ethylene-acrylate copolymers and ethylene-acrylate-glycidyl methacrylate terpolymers; and/or (ii) the weight fraction of the compatibilizer is in the range from 1.0 wt % to 20 wt %, based on the total weight of the adhesion-modified layer.

12. The polymeric film of claim 1, where the adhesion-modified layer is based on a mixture which comprises at least one polyolefin and at least one polyamide alloy, where (i) the polyamide alloy is a polyamide-based thermoplastic alloy; and/or (ii) the weight fraction of the polyamide alloy is in the range from 10 wt % to 60 wt %, based on the total weight of the adhesion-modified layer; and/or (iii) the at least one polyolefin is selected from the group consisting of polyethylene homopolymer, polyethylene copolymer, polypropylene homopolymer and polypropylene copolymer.

13. The polymeric film of claim 1, which as well as the adhesion-modified layer and the layer of the coating material comprises a further layer.

14. The polymeric film of claim 13, where the further layer is disposed on that surface side of the adhesion-modified layer that faces away from the coating material; and/or forms one of the two outer sides of the polymeric film; and/or is furnished with release properties on its surface side facing away from the adhesion-modified layer.

15. The polymeric film of claim 1, which has a total layer thickness of at least 30 μm.

16. The polymeric film of claim 1, which has at room temperature an elongation at break of at least 100%.

17. The polymeric film of claim 1, which is embossed on at least one side.

18. A method for producing a polymeric film for coating plastics moldings with a coating material of claim 1, comprising the steps of: (a-1) providing a film comprising an adhesion-modified layer which forms at least one of the two outer sides of the film; (a-2) wholly or partly coating the outer side with a coating material; and (a-3) drying and/or curing the coating material.

19. A method for coating plastics moldings with a coating material, comprising the steps of (a) providing a polymeric film of claim 1; (b) forming the polymeric film, optionally at room temperature; (c) contacting the coating material with a curable plastics composition; and (d) curing the plastics composition; where the bond adhesion of the coating material to the cured composition is greater than the bond adhesion of the coating material to the adhesion-modified layer of the polymeric film; optionally wherein the curable composition is a polyurethane foam.

20. (canceled)

21. An article comprising a plastics molding coated with the coating material of the polymeric film of claim 1.

22. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0148] The invention is elucidated schematically below with FIGS. 1 to 6.

[0149] FIG. 1 shows schematically a preferred embodiment of the polymeric film of the invention, with layer of coating material (1), adhesion-modified layer (2), core layer (3) and further layer (4) in the as yet unformed state.

[0150] FIG. 2 shows schematically how the polymeric film of the invention as per FIG. 1 is applied to a mold (5) for producing plastics moldings and is given an airtight seal at the edges. The mold (5) thus forms, together with the polymeric film, a cavity, with the further layer (4) facing the interior of the cavity.

[0151] FIG. 3 shows schematically the polymeric film as per FIG. 2 after having been formed in the mold (5), so that the formed polymeric film conforms to the inner surface of the mold (5). The further layer (4) of the polymeric film in this case touches the inner surface of the mold (5). The layer of coating material (1) is facing the interior of the shape produced by forming.

[0152] FIG. 4 shows the production of a plastics molding (6) from a curable plastics composition in the interior of the shape produced by the forming, by injection of a polyurethane foam, for example.

[0153] FIG. 5 shows the plastics molding (6), removed from the mold (5) (not depicted), after the plastics composition has cured. Because the adhesion of the further layer (4) to the inner surface of the mold (5) (not depicted) is low, the plastics molding (6) can be removed without residue together with the adhering layer of the coating material (1) and the other layers of the polymeric film. In this state the polymeric film protects the plastics molding (6) together with the coating material layer (1) adhering thereto.

[0154] FIG. 6 shows schematically how the polymeric film can be peeled from the plastics molding (6) without the layer of the coating material (1). Because the adhesion of the coating material (1) to the plastics molding (6) is stronger than the adhesion of the coating material (1) to the adhesion-modified layer (2) of the polymeric film, the split takes place between the layer of the coating material (1) and the adhesion-modified layer (2). The coating material (1) therefore remains on the plastics molding (6), and the outer surface of the coating material is exposed without residue. In this way the coating material (1) has been transferred from the polymeric film to the plastics molding (6).

LIST OF REFERENCE NUMERALS

[0155] (1)—layer of coating material
(2)—adhesion-modified layer
(3)—core layer
(4)—further layer
(5)—mold
(6)—plastics molding

[0156] The examples which follow elucidate the invention, but should not be interpreted limitingly.

[0157] Three different polymeric films were produced respectively from three layers, with a total film thickness (without coating material) of 60 μm. The composition of the adhesion-modified layer was varied in terms of the amount of adhesion promoter; all other parameters were kept constant.

[0158] The polymeric films thus produced were coated on the surface of the adhesion-modified layer (first outer side) with a commercially available 2-component polyurethane varnish as coating material. To produce the sample strips, the 2-component polyurethane varnish was applied by knife coating to a sheet in DIN A4 format of the polymeric film, in an amount such that the layer thickness of the varnish after drying in a forced air oven was 40 μm.

[0159] After the curing/drying of the polyurethane varnish (coating material), determinations were made of the release forces between the adhesion-modified layer and the coating material. The film construction and the release forces measured are collated in the table below:

TABLE-US-00006 1 2 3 Adhesion-modified layer (first outer side) Layer thickness: 17 μm 17 μm 17 μm rTPO (Adflex ® Q 100 F) 92.3% 65.3%   50% Adhesion promoter (Admer QB 520 E)   0%   27%   50% Additives (UV stabilizer, antiblocking  7.7%  7.7%  7.7% agent, processing aid) Core layer Layer thickness: 26 μm 26 μm 26 μm rTPO (Adflex ® Q 100 F)   80%   80%   80% HeCo PP (Inspire ® D137)   16%   16%   16% Additives (UV stabilizer, dye)   4%   4%   4% Further layer (second outer side) Layer thickness: 17 μm 17 μm 17 μm rTPO (Adflex ® Q 100 F) 65.3% 65.3% 65.3% HeCo PP (Inspire ® D137)   27%   27%   27% Additives (UV stabilizer, antiblocking  7.7%  7.7%  7.7% agent, processing aid) Release force [cN/cm] 2.0 ± 0.1 4.0 ± 0.3 5.3 ± 0.3

[0160] The release forces were determined in a method based on the Finat test method (without storage) on strips with a width of 40 mm of the sheet in DIN A4 format, by means of a model Z0.5 tensile testing machine from Zwick/Roell. Measurement took place on sets of three strips. The strips were adhered by the varnish side to a metal support plate furnished with a double-sided adhesive tape (CMC 10730). The metal support plate was introduced into the bottom clamping jaw of the test apparatus, and the film was parted from varnish at a lower edge adhered to a stiff film strip, which was introduced into the upper clamping jaw. The measurement took place at 300 mm/min.