Method for preparing a transparent polymer material including mineral nanoparticles with a shape factor strictly higher than 1.0
View Patent ↗The present invention provides a method of preparing a transparent polymer material, the method comprising steps i) and ii) in any order, the steps consisting in: i) mixing: mineral nanoparticles having a form factor strictly greater than 1.0; and a polymer matrix comprising a quantity of at least 80% by weight of a polycarbonate (PC) first thermoplastic polymer and of a second transparent thermoplastic polymer other than the first thermoplastic polymer, in order to obtain a mixture; and ii) heating the polymer matrix to the molten state, on its own or in the mixture; to obtain the transparent, polymer material, the mixture of step i) comprising a quantity of mineral nanoparticles having a form factor strictly greater than 1.0 that is strictly less than 5% by weight.
1. A method of preparing a transparent polymer material, said method comprising the steps of, in any order:
i) mixing:
mineral nanoparticles having a form factor strictly greater than 1.0; and
a polymer matrix comprising a quantity of at least 80% by weight of a polycarbonate (PC) first thermoplastic polymer and of a second transparent thermoplastic polymer other than the first thermoplastic polymer;
in order to obtain a mixture; and
ii) heating the polymer matrix to the molten state, on its own or in the mixture;
in order to obtain the transparent polymer material, the mixture of step i) comprising a quantity of mineral nanoparticles having a form factor strictly greater than 1.0 that is strictly less than 5% by weight, and step i) not involving mineral nanoparticles in the form of a premixture obtained with a thermoplastic polymer in the molten state selected from the group consisting of polycarbonate (PC), polystyrene (PS), and polymethyl methacrylate (PMMA).
2. A method according to claim 1 , wherein the polymer matrix includes at least 90% by weight of the polycarbonate first thermoplastic polymer.
3. A method according to claim 1 , wherein the form factor is greater than or equal to 2.
4. A method according to claim 1 , wherein the second polymer is selected from the consisting of homopolymers of styrene, of acrylate, and of acrylamide, and a mixture thereof.
5. A method according to claim 1 , wherein the second polymer is selected from the group consisting of copolymers of styrene, of acrylate, of acrylamide, and of polycarbonate monomer, and a mixture thereof.
6. A method according to claim 1 , wherein the mineral nanoparticles having a form factor strictly greater than 1.0 are selected from the group consisting of nanoparticles of carbonates of alkaline earth metals, of phyllosilicates, and of metallic oxides.
7. A method according to claim 1 , wherein the mineral nanoparticles having a form factor strictly greater than 1.0 are selected from the group consisting of nanoparticles of calcium carbonate, of montmorillonite, of alumina, and of boehmite.
8. A method according to claim 1 , wherein the mixture of step i) includes a quantity of at most 2% by weight of mineral nanoparticles having a form factor strictly greater than 1.0.
9. A method according to claim 1 , wherein the mixture of step i) further comprises mineral nanoparticles having a form factor equal to 1.
10. A method according to claim 9 , wherein the mineral nanoparticles having a form factor equal to 1 are selected from the group consisting of nanoparticles of carbonates of alkaline-earth metals, of sulfates of alkaline-earth metals, of metallic oxides, of metalloid oxides, and of siloxanes.
11. A method according to claim 9 , wherein the mixture of step i) comprises a quantity of at most 10% by weight mineral nanoparticles.
12. A method according to claim 1 , wherein the size of the mineral nanoparticles is at most 300 nm.
13. A method according to claim 1 , the mixture of step i) further includes at least one antioxidant.
14. A method according to claim 13 , wherein the mixture of step i) includes a quantity of at most 5% by weight antioxidant.
15. A method according to claim 13 , wherein the antioxidant comprises a phosphite.
16. A method according to claim 2 , wherein the polymer matrix includes at least 95% by weight of the polycarbonate first thermoplastic polymer.
17. A method according to claim 3 , wherein the form factor is greater than or equal to 5.
18. A method according to claim 17 wherein the form factor is greater than or equal to 10.
19. A method according to claim 18 , wherein the form factor is greater than or equal to 50.
20. A method according to claim 19 , wherein the form factor is greater than or equal to 100.
21. A method according to claim 20 , wherein the form factor is greater than or equal to 200.
22. A method according to claim 8 , wherein the mixture of step i) includes a quantity of at most 1% by weight of mineral nanoparticles having a form factor strictly greater than 1.0.
23. A method according to claim 22 , wherein the mixture of step i) includes a quantity of at most 0.5% by weight of mineral nanoparticles having a form factor strictly greater than 1.0.
24. A method according to claim 12 , wherein the size of the mineral nanoparticles is at most 100 nm.
25. A method according to claim 24 , wherein the size of the mineral nanoparticles is at least 10 nm, and at most 70 nm.
26. A method according to claim 14 , wherein the mixture of step i) includes a quantity of at most 2% by weight antioxidant.