Polypropylene wrap end seals and process for making same

Claim 2

A process for sealing an end of a voided polypropylene film wrap comprising the steps of: (a) inserting said end of said polypropylene wrap between a 50 pitch knurl wheel and a 50 pitch idler wheel; (b) pressing at least one of said knurl and idler wheels against said polypropylene wrap and said other wheel so as to effect a mechanically crimped seal; and (c) heating said knurl wheel prior to and during said pressing step (b) to a temperature from 110° F. to 140° F. in order to increase the flexibility of said polypropylene wrap but not form a heat seal.

Claim 3

The process according to claim 1, wherein only said idler wheel is pressed during said pressing step (b).

Claim 4

The process according to claim 1, wherein each tooth of said knurl and idler wheels has a flat tip portion of 0.003 to 0.005 inches to effect a stronger end seal.

Claim 5

The process according to claim 1, wherein said knurl wheel should have a knurl width of approximately 0.08 to 0.10 inches.

Claim 6

The process according to claim 1, wherein said pressing step (b) exerts a total force/inch of knurl width of approximately 800 to 4050 lbs. on said end to effect a mechanically crimped seal.

Claim 7

A process for forming a voided polypropylene film wrap adapted to receive and have sealed therein an article, said process comprising the steps of: (a) sealing a sheet of voided polypropylene film along its longitudinal edges to form a tube; (b) cutting said tube into an individual wrap so that each wrap has an alternative row of notches at each end; (c) inserting a first end of said wrap between a 50 pitch knurl wheel and a 50 pitch idler wheel; (d) pressing at least one of said knurl and idler wheels against said first end of said wrap and said other wheel so as to effect a mechanically crimped seal; (e) and (f) repeating steps (c) and (d), respectively, for a second end of said wrap; and (g) heating said knurl wheel prior to and during said pressing steps to a temperature from 110° F. to 140° F. in order to increase the flexibility of the polypropylene wrap but not form a heat seal.

Claim 8

A process for forming a voided polypropylene film wrap adapted to receive and have sealed therein an article, said process comprising the steps of: (a) sealing a sheet of voided polypropylene film along its longitudinal edges to form a tube; (b) cutting said tube into an individual wrap so that each wrap has an alternative row of notches at each end; (c) inserting a first end of said wrap between a 50 pitch knurl wheel and a 50 pitch idler wheel; (d) pressing at least one of said knurl and idler wheels against said first end of said wrap and said other wheel so as to effect a mechanically crimped seal; (e) and (f) repeating steps (c) and (d), respectively, for a second end of said wrap; and (g) heating said knurl wheel prior to and during said pressing steps to a temperature from 110° F. to 140° F. in order to increase the flexibility of the polypropylene wrap but not form a heat seal.

Claim 9

The process according to claim 6, further including the steps of introducing each of said individual wraps into a transverse arcuate groove in a rotating turret sealing device and rotating said turret sealing device to a first sealing station where a first end of said wrap is aligned between a 50 pitch knurl wheel and a 50 pitch idler wheel.

Claim 10

The process according to claim 7, wherein said pressing step at said first sealing station comprises the steps of initially pressing said knurl and idler wheels against said first end of said wrap in order to effect a partial mechanical crimp seal along said first end, inserting said article into said wrap through a second end, and thereupon subsequently pressing said knurl and idler wheels against said first end of said wrap in order to complete the mechanical crimp seal along said first end.

Claim 11

The process according to claim 8, further including the step of rotating said turret to a second sealing station where said second end of said wrap is aligned between a 50 pitch knurl wheel and a 50 pitch idler wheel.

Claim 12

The process according to claim 6, wherein said article comprises a tampon.

Claim 13

The process according to claim 6, wherein said pressing step (d) exerts a total force/inch of knurl width of 800 to 2400 lbs. on said first end to effect a mechanical crimped seal.

Claim 14

The process according to claim 6, wherein said pressing step (g) exerts a total force/inch of knurl width of 1350 to 4050 lbs. on said second end to effect a mechanical crimped seal.

Claim 15

Apparatus for use in inserting and sealing an article within a voided polypropylene film wrap comprising: (a) means for forming a sheet of voided polypropylene film into a tube; (b) means for cutting said tube into individual wraps so that each wrap has an alternative row of notches at each end; (c) a rotating turret sealing device including a plurality of transverse acruate grooves adapted to receive each wrap; (d) means for introducing at least one of said individual wraps into at least one of said transverse acruate grooves; (d) means for rotating said turret sealing device such that said at least one of said transverse arcuate grooves is positioned relative to a first sealing station which includes a heated knurl wheel and an idler wheel for sealing at least one end of said at least one wrap; (e) means for sealing said at least one end; (f) means for inserting said article into a second end of said at least one wrap; (g) means for further rotating said turret sealing device such that said at least one transverse arcuate groove is positioned relative to a second sealing stating which includes a heated knurl wheel and an idler wheel for sealing said second end; and (h) means for sealing said second end.

Claim 16

Apparatus for use in inserting and sealing an article within a voided polypropylene film wrap comprising: (a) means for forming a sheet of voided polypropylene film into a tube; (b) means for cutting said tube into individual wraps so that each wrap has an alternative row of notches at each end; (c) a rotating turret sealing device including a plurality of transverse acruate grooves adapted to receive each wrap; (d) means for introducing at least one of said individual wraps into at least one of said transverse acruate grooves; (d) means for rotating said turret sealing device such that said at least one of said transverse arcuate grooves is positioned relative to a first sealing station which includes a heated knurl wheel and an idler wheel for sealing at least one end of said at least one wrap; (e) means for sealing said at least one end; (f) means for inserting said article into a second end of said at least one wrap; (g) means for further rotating said turret sealing device such that said at least one transverse arcuate groove is positioned relative to a second sealing stating which includes a heated knurl wheel and an idler wheel for sealing said second end; and (h) means for sealing said second end.

Claim 17

The apparatus of claim 13, wherein the pitch of the knurl and idler wheels in said first and second sealing stations is between about 45 and about 55.

Claim 18

The apparatus of claim 13, wherein the width of the knurl wheels in said first and second sealing stations is between about 0.080 inches and about 0.100 inches and wherein the tips of the teeth of the knurl and idler wheels in the first and second sealing stations include a flat surface of between about 0.003 and about 0.005 inches.

Claim 19

The apparatus of claim 15, wherein the knurl and idler wheels at the first sealing station are adapted to be pressed together with a force between about 800 and about 1600 lbs and wherein the knurl and idler wheels at the second sealing station are adapted to be pressed together with a force between about 1350 and about 2700 lbs.

Claim 20

The apparatus of claim 13, wherein said knurl wheels are heated to a temperature between about 110° F. and about 140° F.