Injection molded plastic object with an embedded electronic circuit printed on a paper base and method of its production
The invention relates to a method to embed a label essentially consisting of a paper substrate carrying electronic inks and/or a printed electronic circuit and/or device (thereby achieving a paper-based electronic circuit) directly into a moulded plastic piece (also designated as plastic object), the embedding of the paper-based electronic circuit and the production of the plastic piece being performed in a single operation. The invention thus also relates to a method to manufacture plastic objects embedding such label. The invention also concerns a plastic object encompassing a label essentially consisting of a paper substrate carrying electronic inks and/or a printed electronic circuit and/or device (thereby achieving a paper-based electronic circuit) embedded in the moulded plastic and in particular an object obtained by the method disclosed to prepare a moulded plastic piece.
1. A method to manufacture a plastic object embedding a paper-based circuit, comprising steps of:
A. providing or producing a paper-based electronic circuit, for use as an in-mould label, and a mould, the mould being suitable for providing the shape of the plastic object;
B. positioning the paper-based electronic circuit inside the mould;
C. providing liquid plastic in the mould; and
D. allowing the plastic to solidify and recovering the moulded plastic object embedding the paper-based electronic circuit;
wherein the paper-based electronic circuit carries an electronic circuit which is at least partly printed on a paper-based substrate.
2. The method according to claim 1 wherein step A comprises:
producing a paper-based electronic circuit comprising a printed electronic circuit and/or printing an electronic circuit on a paper-based substrate;
wherein the paper-based electronic circuit is optionally produced on a graphically printed paper-based substrate and/or is graphically printed.
3. The method according to claim 1 , wherein the plastic of which the object is made is a thermoplastic and wherein step C comprises injecting the heated thermoplastic and step D comprises allowing the thermoplastic to cool.
4. The method according to claim 3 , wherein the thermoplastic is selected from the group consisting of: polyester, polyamide, polyethylene, polypropylene, polycarbonate, polystyrene, polymethylmethacrylate optionally modified with comonomers, acrylonitrile butadiene styrene, polyvinylchloride, polyether sulfone, polyetherether ketone, polyetherimide and polyphenyleneoxide.
5. The method according to claim 1 , wherein the paper-based substrate is a coated paper, wherein the coating comprises a binder and pigments and is suitable for printing with electronic inks, wherein:
ii) the coating comprises a binder with a glass transition temperature lower than 20° C., wherein the coating comprises 5 to 50 parts by dry weight of the binder; and/or
iii) the paper-based substrate has an ISO brightness and/or D65 brightness in the range 70 to 90.
6. The method according to claim 5 , wherein the paper-based substrate has a Bekk smoothness equal to or higher than 900 s and/or has a gloss at 75° equal to or higher than 70%.
7. The method according to claim 5 , wherein the paper-based substrate is selected among Powercoat® HD and Powercoat® XD papers.
8. The method according to claim 1 , wherein the paper-based substrate and/or the paper-based electronic circuit is devoid of any plastic film.
9. The method according to claim 1 , wherein the printed electronic circuit comprises an ink or inks selected among
iv) organic inks; and
v) inorganic inks.
10. The method according to claim 1 , wherein step A comprises a step of sintering the electronic inks by heating the paper-based electronic circuit.
11. The method according to claim 1 , wherein the printed electronic circuit comprises an antenna.
12. The method according to claim 1 , wherein step A comprises obtaining a paper-based electronic circuit carrying non-printed electronic components in addition to the printed electronic circuit and/or wherein step A comprises appending non-printed electronic components to the paper-based electronic circuit.
13. The method according to claim 12 , wherein the non-printed electronic components comprise a chip.
14. The method according to claim 1 , wherein
(i) the paper-based electronic circuit is embedded at the surface of the plastic object and wherein the circuit is printed on the outer surface, on the inner surface or on both the inner surface and the outer surface of the paper-based label; or
(ii) the paper-based electronic circuit is fully or almost fully embedded inside the plastic object.
15. The method according to claim 1 , wherein step A further comprises a step of applying a plastic overcoat to at least one surface of the paper-based electronic circuit.
16. The method according to claim 15 , wherein said the overcoat comprises a laminated plastic film and/or a coated plastic layer, wherein the plastic is selected among the group consisting of PET, PMMA, PC, PA, PP and PLA.
17. A plastic object obtained by the method of claim 1 , comprising an embedded paper-based electronic circuit comprising a paper-based substrate carrying a printed electronic circuit.
18. The plastic object according to claim 17 , made of a thermoplastic selected from the group consisting of: polyester, polyamide, polyethylene, polypropylene, polycarbonate, polystyrene, polymethylmethacrylate optionally modified with comonomers, acrylonitrile butadiene styrene, polyvinylchloride, polyether sulfone, polyetherether ketone, polyetherimide and polyphenyleneoxide.
19. The plastic object according to claim 17 , wherein the paper-based substrate is a coated paper, wherein the coating comprises a binder and pigments and is suitable for printing with electronic inks, wherein:
ii) the coating comprises a binder with a glass transition temperature lower than 20° C., wherein the coating comprises 5 to 50 parts by dry weight of such binder; and/or
iii) the paper-based substrate has an ISO brightness and/or D65 brightness in the range 70 to 90.
20. The plastic object according to claim 17 , wherein:
(i) the paper-based electronic circuit is embedded at the surface of the plastic object, and wherein the printed electronic circuit is on the outer surface, the inner surface, or both the outer surface and the inner surface of the paper-based electronic circuit; or
(ii) the paper-based electronic circuit is fully or almost fully embedded inside the plastic object.
21. The plastic object according to claim 17 , wherein the outer surface of the paper-based electronic circuit is at least partly covered by a protective plastic overcoat.