One-step formation of an integrated composite structure comprising cured mortar layers and a polyurethane layer by 3D printing
The present invention relates to a process of fabricating a multi-layer composite structure by 3D printing, said composite structure comprises at least one cured mortar layer formed by curing of a mortar composition, and at least one polyurethane layer formed by polymerization of a first polyurethane forming composition, wherein said mortar composition and said first polyurethane forming composition are dispensed individually and simultaneously via adjacent printing nozzles. The mortar composition is optionally modified by a second polyurethane forming composition.
1. A process of fabricating a multi-layer composite structure by 3D printing, the composite structure comprising at least one cured mortar layer formed by curing of a mortar composition, and at least one polyurethane layer formed by polymerization of a first polyurethane forming composition, wherein
the mortar composition and the first polyurethane forming composition are dispensed individually and simultaneously via adjacent printing nozzles,
the mortar composition is modified before or after being dispensed by a second polyurethane forming composition to be a modified mortar composition,
content of the second polyurethane forming composition is 0.1% to 50% by weight based on total weight of the modified mortar composition,
pot life t3 of the modified mortar composition is 0.05 to 2 hours,
an initial setting time t2 of the mortar composition when unmodified is greater than a gel time of the second polyurethane forming composition, and
the gel time of the second polyurethane forming composition is greater than the pot life t3.
2. The process according to claim 1 , wherein each of the at least one polyurethane layer is sandwiched between two of the at least one cured mortar layer.
3. The process according to claim 1 , wherein slump of the modified mortar composition is 10 to 100 mm.
4. The process according to claim 3 , wherein the slump of the modified mortar composition is 30 to 90 mm.
5. The process according to claim 3 , wherein the slump of the modified mortar composition is 50 to 70 mm.
6. The process according to claim 1 , wherein gel time t1 of the first polyurethane forming composition is 0.5 to 10 minutes.
7. The process according to claim 6 , wherein the gel time t1 of the first polyurethane forming composition is 1 to 5 minutes.
8. The process according to claim 1 , wherein the initial setting time t2 is 0.5 to 4 hours.
9. The process according to claim 8 , wherein the initial setting time t2 is 1 to 2 hours.
10. The process according to claim 1 , wherein
gel time t1 of the first polyurethane forming composition is 0.5 to 10 minutes,
the initial setting time t2 is 0.5 to 4 hours, and
t2-t1<2 hours.
11. The process according to claim 10 , wherein t2-t1<1.5 hours.
12. The process according to claim 10 , wherein t2-t1<1 hours.
13. The process according to claim 1 , wherein
gel time t1 of the first polyurethane forming composition is 0.5 to 10 minutes, and
t3-t1<0.5 hours.
14. The process according to claim 13 , t3-t1<0.4 hours.
15. The process according to claim 13 , wherein t3-t1<0.25 hours.
16. The process according to claim 1 , wherein the mortar composition is modified by the second polyurethane forming composition by mixing with the second polyurethane forming composition before being introduced into the printing nozzles.
17. The process according to claim 1 , wherein the first polyurethane forming composition comprises:
(1) Component A comprising polyol; and
(2) Component B comprising isocyanate,
wherein Component A and Component B are mixed after being introduced into the printing nozzles.
18. The process according to claim 1 , wherein the pot life t3 of the modified mortar composition is 0.1 to 1 hours.
19. The process according to claim 1 , wherein the pot life t3 of the modified mortar composition is 0.2 to 0.5 hours.
20. The process according to claim 1 , wherein the content of the second polyurethane forming composition is 5% to 30% by weight based on the total weight of the modified mortar composition.
21. The process according to claim 1 , wherein the content of the second polyurethane forming composition is 10% to 20% by weight based on the total weight of the modified mortar composition.
22. The process according to claim 1 , wherein the second polyurethane composition comprises a polyester polyol and/or polyether polyol with two or more hydroxyl groups, and an isocyanate selected from aliphatic, alicyclic and aromatic isocyanates or prepolymer thereof with two or more isocyanate groups.