A cap for use in forming a sealed container with a fluid-holding vessel. The cap includes a downwardly tapered inner wall having a plurality of radially extending striations for improving the penetrability of the cap and for facilitating the formation of air passageways.
1. A plastic cap for forming a sealed container when fitted onto an open end of a fluid-holding vessel, said cap comprising:
an opening defined by a top wall; and
a downwardly tapered inner wall positioned beneath the opening and structurally interrelated to the top wall, wherein the inner wall includes a plurality of radially extending striations formed therein, and wherein the striations define a plurality of generally wedge-shaped sections in the inner wall.
2. The cap of claim 1 further comprising means for fixedly associating the cap with the open end of the fluid-holding vessel.
3. The cap of claim 1 , wherein the inner wall depends from the top wall.
4. The cap of claim 1 further comprising a lower annular wall joining the top wall to the inner wall.
5. The cap of claim 1 further comprising an upper annular wall extending upwardly from the top wall.
6. The cap of claim 5 further comprising a wick contained within the cap.
7. The cap of claim 6 , wherein the wick is positioned substantially above the top wall.
8. The cap of claim 6 , wherein the wick comprises an absorbent material.
9. The cap of claim 8 , wherein the wick is a pile fabric.
10. The cap of claim 6 further comprising a seal affixed to a top surface of the upper annular wall.
11. The cap of claim 1 , wherein the inner wall is conically shaped and has an angle of from about 25° to about 65° relative to the longitudinal axis of the cap.
12. The cap of claim 1 , wherein the inner wall has a closed rounded bottom.
13. The cap of claim 1 , wherein the thickness ratio between non-striated and striated portions of the inner wall is in the range of about 10:1 to about 1.25:1.
14. The cap of claim 1 , wherein the average thickness of striated portions of the inner wall is between about 0.002 inches and about 0.008 inches, and wherein the average thickness of non-striated portions of the inner wall is between about 0.01 inches and about 0.02 inches.
15. The cap of claim 1 , wherein the striations are formed in an inner surface or both the inner and outer surfaces of the inner wall.
16. The cap of claim 15 , wherein the striations are formed in an inner surface of the inner wall.
17. The cap of claim 1 , wherein the inner wall has between 3 and 12 of the striations.
18. The cap of claim 1 , wherein each of the striations comprises a radially extending groove in the inner wall.
19. The cap of claim 1 further comprising one or more radially extending ribs formed on an inner surface of the inner wall, each rib being positioned between a pair of adjacent striations.
20. The cap of claim 1 , wherein an inner surface of the inner wall is at least partially coated with a lubricant.