Process of forming a compression-molded closure liner
View Patent ↗A container closer includes a cap and a seal liner coupled to the cap. The cap is configured to mount on a filler neck of a container to mate the seal liner with a brim of the filler neck.
1. A process of forming a closure adapted to be coupled to a filler neck of a container to close a mouth opening into a passageway formed in the filler neck and to establish a sealed connection between the closure and the filler neck, the process comprising the steps of
providing a cap formed to include an interior region,
depositing a gob of plastics material onto an interior deck of the cap to locate the gob of plastics material in the interior region of the cap, and
moving a liner-forming die having a one-piece mold face into the interior region of the cap to cause the one-piece mold face to engage and compress the gob of plastics material to cause plastics material in the gob to flow in a mold chamber defined between the liner-forming die and the interior deck of the cap to form a compression-molded seal liner on the interior deck of the cap in the interior region of the cap, wherein
the compression-molded seal liner includes a membrane and an annular sealing rim surrounding the membrane and mating with a perimeter portion of the membrane and
the one-piece mold face is formed to include a membrane-forming surface, an annular sealing rim-forming trench surrounding the membrane-forming surface, and channel means arranged to interrupt the membrane-forming surface for receiving a portion of the plastics material in the gob and conducting the portion in radially outward directions toward the annular sealing rim-forming trench of the one-piece mold face and a perimeter edge of the interior deck during movement of the one-piece mold face toward the interior deck to cause the membrane-forming surface to be covered completely with plastics material and to cause plastics material to flow into the annular sealing rim-forming trench to form the annular sealing rim therein.
2. The process of claim 1 , wherein the compression-molded seal liner further includes a cross-shaped raised ridge coupled to the membrane and surrounded by the annular sealing rim.
3. The process of claim 2 , wherein the cross-shaped raised ridge is formed from plastics material extant in the channel means during movement of the mold face of the liner-forming die toward the interior deck of the cap.
4. The process of claim 1 , wherein the channel means includes a first ridge-leg channel communicating at an outlet end thereof with the annular seal rim-forming trench and providing a first fill path for plastics material extending toward the annular seal rim-forming trench.
5. The process of claim 4 , wherein the channel means further includes a second ridge-leg channel communicating at an end thereof with the annular seal rim-forming trench and providing a second fill path for plastics material extending toward the annular seal rim-forming trench.
6. The process of claim 5 , wherein the membrane-forming surface is round and has a circular perimeter edge bordering the annular seal rim-forming trench and a diameter extending between two points on the circular perimeter edge and the first and second ridge-leg channels are aligned with one another to extend in opposite directions along the diameter of the circular perimeter edge of the membrane-forming surface.
7. The process of claim 6 , wherein each of the first and second ridge-leg channels includes an inlet end arranged to lie in spaced-apart relation to the annular seal rim-forming trench, the channel means further includes a leg-connector basin arranged to lie between and in fluid communication with the inlet end of each of the first and second ridge-leg channels, and the gob of plastics material at least in part is moved into the leg-connector basin during the moving step.
8. The process of claim 5 , wherein the channel means further includes a third ridge-leg channel communicating at an outlet end thereof with the annular seal rim-forming trench and providing a third fill path for plastics material extending toward the annular seal rim-forming trench and each of the first, second, and third ridge-leg channels is arranged to extend from the annular seal rim-forming trench in a radially inwardly extending direction toward a center point located in the center of the membrane-forming surface.
9. The process of claim 8 , wherein the channel means further includes a leg-connector basin arranged to lie at the center point in fluid communication with an inlet end of each of the first, second, and third ridge-leg channels and the gob of plastics material is moved at least in part into the leg-connector basin during the moving step.
10. The process of claim 5 , wherein the channel means further includes a third ridge-leg channel communicating at an outlet end thereof with the annular seal rim-forming trench and providing a third fill path for plastics material extending toward the annular seal rim-forming trench and a fourth ridge-leg channel communicating at an outlet end thereof with the annular seal rim-forming trench and providing a fourth fill path for plastics material extending toward the annular seal rim-forming trench and wherein the membrane-forming surface includes a first raised pad bounded by the first and second ridge-leg channels and a first curved portion of the annular seal rim-forming trench, a second raised pad bounded by the second and third ridge-leg channels and a second curved portion of the annular seal rim-forming trench, a third raised pad bounded by the third and fourth ridge-leg channels and a third curved portion of the annular seal rim-forming trench, and a fourth raised pad bounded by the fourth and first ridge-leg channels and a fourth curved portion of the annular seal rim-forming trench.
11. The process of claim 10 , wherein each of the first, second, third, and fourth raised pads has a teardrop-shaped perimeter edge.
12. The process of claim 10 , wherein each of the first, second, third, and fourth raised pads includes a flat surface arranged to engage plastics material in the gob located outside of the first, second, third, and fourth ridge-leg channels during movement of the mold face of the liner-forming die toward the interior deck of the cap and the flat surfaces are arranged to lie in substantially coplanar relation to one another.
13. The process of claim 12 , wherein each of the flat surfaces has a teardrop-shaped perimeter edge.
14. The process of claim 1 , wherein the channel means includes a ridge-leg channel including an inner section located between the annular seal-rim forming trench and a center point located in the center of the membrane-forming surface and an outer section arranged to lie between and in fluid communication with the inner section and the annular seal rim-forming trench and the outer section is bell-shaped and has a width that widens progressively in a direction extending from the inner section toward the annular seal rim-forming trench.
15. The process of claim 14 , wherein the membrane-forming surface includes a first raised pad and a second raised pad arranged to lie in spaced-apart relation to the first raised pad to locate the inner and outer sections of the ridge-leg channel therebetween.
16. The process of claim 15 , wherein the first raised pad includes a curved convex exterior perimeter edge bordering one side of the bell-shaped outer section of the ridge-leg channel and having a radius of curvature of about 0.3 inches, the second raised pad includes a curved convex exterior perimeter edge bordering an opposite side of the bell-shaped outer section of the ridge-leg channel and having a radius of curvature of about 0.3 inches, and the curved convex exterior perimeter edges of the first and second raised pads cooperate to form flow-expansion means for expanding flow of plastics material flowing from the inner section into the annular seal rim-forming trench through the belt-shaped outer section to transfer plastics material in the gob into the annular seal rim-forming trench during the moving step.
17. The process of claim 15 , wherein the inner section of the ridge-leg channel is defined between an exterior perimeter edge of the first raised pad and a confronting exterior perimeter edge of the second raised pad arranged to lie in substantially spaced-apart parallel relation to the exterior perimeter edge of the first raised pad to provide the inner section of the ridge-leg channel with a substantially uniform width.
18. The process of claim 17 , wherein the first raised pad includes a curved convex exterior perimeter edge bordering one side of the bell-shaped outer section of the ridge-leg channel and having a radius of curvature of about 0.3 inches, the second raised pad includes a curved convex exterior perimeter edge bordering an opposite side of the bell-shaped outer section of the ridge-leg channel and having a radius of curvature of about 0.3 inches, and the curved convex exterior perimeter edges of the first and second raised pads cooperate to form flow-expansion means for expanding flow of plastics material flowing from the inner section into the annular seal rim-forming trench through the belt-shaped outer section to transfer plastics material in the gob into the annular seal rim-forming trench during the moving step.
19. The process of claim 14 , wherein the channel means further includes a basin arranged to lie at the center point, the inner section is arranged to lie in fluid communication with the basin, the gob of plastics material is moved at least in part into the basin during the moving step, and plastics material in the gob moves through the inner and outer sections of the ridge-leg channel along a fill path into the annular seal rim-forming trench during the moving step.
20. The process of claim 1 , wherein the mold chamber has a constant volume during engagement of the interior deck of the cap by the one-piece mold face.
21. The process of claim 1 , wherein the one-piece mold face is also formed to include a basin and a ridge-leg channel, the ridge-leg channel includes an inner section located between the annular seal rim-forming trench and the basin and an outer section arranged to lie between and in fluid communication with the inner section and the annular seal rim-forming trench, the gob of plastics material is deposited at least in part into the basin during the depositing step, and the plastics material in the gob moves through the inner and outer section of the ridge-leg channel away from the basin in a radially outward direction toward and into the annular seal rim-forming trench during the moving step.
22. The process of claim 21 , wherein the one-piece mold face is formed to include four ridge-leg channels and each pair of adjacent ridge-leg channels cooperates to form an included angle of about 90° therebetween to cause the compression-molded seal liner to have four ridge legs and to cause each pair of adjacent ridge legs to cooperate to form an included angle of about 90° therebetween.
23. The process of claim 21 , wherein the one-piece mold face is formed to include two ridge-leg channels and each pair of adjacent ridge-leg channels cooperates to form an included angle of about 180° therebetween to cause the compression-molded seal liner to have two ridge legs that cooperate to form an included angle of about 180° therebetween.