Methods for manufacturing fiber-based beverage lids
Methods and apparatus for vacuum forming a beverage lid using a fiber-based slurry. The slurry comprises a moisture barrier component in the range of 0.5%-10% by weight, a rigidity component in the range of 1%-4% by weight, and a polycationic component in the range of about 1%-4%.
1. A method of manufacturing a lid for a beverage container, comprising:
providing a first slurry mixture including: i) a fiber base of softwood (SW)/bagasse at a ratio in the range of about 7:3 to about 9:1; and ii) a rigidity component in the range of about 1%-4% by weight;
adding, to the first slurry mixture, a moisture barrier component in the range of about 0.5%-10% by weight to yield a second slurry mixture, where the moisture barrier component is different than the rigidity component;
immersing a mold assembly including a wire mesh comprising a mirror image of the lid into the second slurry mixture, wherein the wire mesh comprises a lock ring feature having a non-positive draft region;
drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the wire mesh surface; and
removing the finished lid from the mold assembly utilizing a retractable piston.
2. The method of claim 1 , wherein the moisture barrier component is in the range of about 1%-4%.
3. The method of claim 1 , wherein the moisture barrier component comprises alkyl ketene dimer (AKD).
4. The method of claim 3 , wherein the alkyl ketene dimer comprises long chain diketenes.
5. The method of claim 1 , wherein the rigidity component comprises polyamide-epichlorohydrin (PAE) resin.
6. The method of claim 1 , wherein the rigidity component comprises liquid starch.
7. The method of claim 1 , wherein the rigidity component comprises a dry inorganic salt.
8. The method of claim 1 , wherein:
the moisture barrier comprises AKD in the range of about 4%;
the slurry comprises bagasse; and
the slurry further comprises a polycationic material in the range of about 1%-4% by weight.
9. A method of vacuum forming a beverage container lid, comprising:
providing a fiber based mixture comprising at least one of softwood (SW) and bagasse;
immersing a mold assembly including a wire mesh comprising a mirror image of the lid into the mixture, wherein the wire mesh comprises a lock ring feature having a non-positive draft region;
drawing a vacuum across the wire mesh to cause fiber particles to accumulate at the wire mesh surface to thereby form a fiber based lid having a lock ring region corresponding to the lock ring feature; and
removing the finished lid from the mold assembly by forcing the lock ring region of the lid around the lock ring feature of the mold assembly;
wherein removing comprises urging a piston against an inside surface of the lid.
10. The method of claim 9 , wherein the non-positive draft region comprises zero draft.
11. The method of claim 9 , wherein the non-positive draft region comprises a negative draft.
12. The method of claim 9 , wherein the mixture further comprises a moisture barrier component.
13. The method of claim 9 , wherein the mixture further comprises a rigidity component which is different than the moisture barrier component.
14. The method of claim 9 , wherein the mixture comprises a SW/bagasse ratio in the range of about 7:3 to about 9:1.
15. The method of claim 9 , wherein the mixture comprises a rigidity component in the range of about 1%-4% by weight.
16. The method of claim 9 , wherein the mixture further comprises a moisture barrier component which is different than the rigidity component.
17. The method of claim 9 , wherein the moisture barrier component comprises alkyl ketene dimer (AKD).
18. The method of claim 9 , wherein the rigidity component comprises liquid starch.
19. A method of vacuum forming a concave lid having a lock ring region which exhibits a non-positive draft, the method comprising:
providing an aqueous mixture comprising at least one of softwood (SW) and bagasse;
immersing a wire mesh mold into the mixture, wherein the mold comprises a lock ring feature corresponding to the lock ring region;
drawing a vacuum across the mold such that fiber particles accumulate at the mold surface to thereby form a finished lid; and
removing the finished lid from the mold by urging the lock ring region of the lid away from the lock ring feature of the mold;
wherein removing comprises urging a piston against an inside surface of the lid.