NON-UNIFORMLY PERFORATED PLASTIC BAG

Abstract

Provided is a perforated plastic bag wherein the volume of said bag is 100 liters or more; wherein the average perforation diameter is 500 micrometers or less; wherein said plastic bag comprises a lower zone and a top zone, wherein the perforation density of said lower zone is greater than the perforation density of said top zone. Also provided is a method of using such a plastic bag.

Claims

1.-8. (canceled)

9. A package comprising a box and a non-uniformly perforated plastic bag located within the box, wherein the non-uniformly perforated plastic bag comprises a lower zone having a perforation density and a top zone having a perforation density, and wherein the perforation density of the lower zone is greater than the perforation density of the top zone.

10. The package of claim 9, wherein the package further comprises a kraft paper liner located between a portion of the non-uniformly perforated plastic bag and a bottom of the box.

11. The package of claim 10, wherein a portion of the kraft paper liner is located between the lower zone of the non-uniformly perforated plastic bag and the top zone of the non-uniformly perforated plastic bag.

12. The package of claim 10, wherein the box comprises a first side, a second side, and the bottom of the box extends between and interconnects the first side and the second side.

13. The package of claim 12, wherein the kraft paper liner has a first end and a second end and the kraft paper liner is arranged so that a portion of the first end is located between the second end and the bottom of the box.

14. The package of claim 13, wherein a portion of the top zone of the non-uniformly perforated plastic bag is located between the first end of the kraft paper liner and the side of the box.

15. The package of claim 10, wherein the kraft paper liner comprises perforations having a diameter of about 0.5 cm or higher.

16. The package of claim 9, wherein the box comprises holes having a diameter of about 20 mm or higher.

17. The package of claim 9, wherein the non-uniformly perforated plastic bag is closed by a gripping device.

18. The package of claim 17, wherein the gripping device is a rubber band or tape.

19. The package of claim 9, wherein a ratio of the perforation density of said lower zone to the perforation density of said top zone is 1.1:1 or higher.

20. The package of claim 9, wherein the package does not include kraft paper liner.

21. A non-uniformly perforated plastic bag comprising i) a top zone having a banana-specific perforation defined as a total area of perforations in the top zone divided by a mass of bananas enclosed by the top zone, and ii) a lower zone having a banana-specific perforation of about 0.025 mm.sup.2/kg or more, defined as a total area of perforations in the lower zone divided by a mass of bananas enclosed by the lower zone, wherein a ratio of the banana-specific perforation of the lower zone to the banana-specific perforation of the top zone is about 6:1 or less.

22. The non-uniformly perforated plastic bag of claim 21, wherein the banana-specific perforation the top zone is about 3 mm.sup.2/kg or less.

23. The non-uniformly perforated plastic bag of claim 21, wherein the banana-specific perforation of the top zone is about 0.05 mm.sup.2/kg to about 2 mm.sup.2/kg.

24. The non-uniformly perforated plastic bag of claim 21, wherein the ratio of the banana-specific perforation of the lower zone to the banana-specific perforation of the top zone is about 0.3:1 or higher.

25. The non-uniformly perforated plastic bag of claim 21, wherein the ratio of the banana-specific perforation of the lower zone to the banana-specific perforation of the top zone is about 0.4:1 to about 5:1.

26. The non-uniformly perforated plastic bag of claim 21, wherein the non-uniformly perforated plastic bag includes a first set of lines of perforation and a second set of lines of perforation that are generally shorter than the first set of lines of perforation.

27. A package comprising a box comprising holes, and a non-uniformly perforated plastic bag located within the box, wherein the package is configured with the means for maintaining atmospheric conditions inside the non-uniformly perforated plastic bag so that harvested bananas can be stored in the package for 7 to 20 days.

28. The package of claim 27, wherein the non-uniformly perforated plastic bag comprises a lower zone and a top zone, each of the lower zone and the top zone having a perforation density, and the perforation density of the lower zone is greater than the perforation density of the top zone.

Description

COMPARATIVE EXAMPLE C1 to C4

Single Chamber Bag In-Country Packaging

[0101] A mono layer film for Comparative Example C1 and Comparative Example C2 was produced by extruding a 94 cm (37 inch) diameter tube on a conventional upward blown film line. A mono layer film for Comparative Example C3 and Comparative Example C4 was produced by extruding a 99.7 cm (39.25 inch) diameter tube on a conventional upward blown film line. The composition of the film and the film properties are provided in Tables 1A and 1B. The tube film was sealed and scored for tear off on the film line to produce bags on a roll. The tube film was perforated using a beam compression laser perforation system as follows and as detailed in Table 2A.

[0102] In Comparative Examples C1 to C4, each bag had four lines of perforations similar to lines 9, 10, 13, and 14 in FIG. 2. Every line of perforation ran the length of the bag; there was no abbreviated line of perforations similar to lines 11 and 12 in FIG. 2. In Comparative Examples C1 and C2, the distances from the left side of the bag to each line of perforation was as follows: 3.8 cm, 45.7 cm, 83.8 cm, and 89.9 cm. In Comparative Examples C3 and C4, the distances from the left side of the bag to each line of perforation was as follows: 4.1 cm, 50.5 cm, 92.1 cm, and 96.4 cm.

[0103] The perforation area is in units of mm.sup.2; for the bottom 45.7 cm (18 inch) length of the bag and for the top 91.4 cm (36 inch) length of the bag is given in Table 2B.

[0104] The perforated bags were used to package bananas in Guatemala in the conventional manner as shown in FIG. 1 and shipped to the United States for ripening. The bananas were ripened as follows. The temperatures shown are pulp temperatures; if necessary, the thermostat was lowered so that pulp temperature remained at the desired temperature despite any respiration that may be taking place in the bananas.

[0105] day 0: 17.8? C. (64? F.), in normal air

[0106] day 1: 17.8? C. (64? F.), ethylene at 200 ppm for 24 hours

[0107] day 2: 17.8? C. (64? F.), room was vented for 30 min., then re-sealed.

[0108] day 3: 17.8? C. (58? F.)

[0109] day 4: 14.4? C. (58? F.)

[0110] day 5: 14.4? C. (58? F.)

[0111] While still in the bags, the bananas were then treated with 1-methylcyclopropene (1-MCP) on Day 5 as follows. The bags with the bananas inside were place in an enclosed volume, at 13.3? C. (56? F.), and sufficient 1-MCP was released into that volume to give a concentration of 1000 ppb. The volume remained enclosed and was held at 13.3? C. for 12 hours. The bananas were then removed from the ripening room and stored at 21.7? C. (71? F.). The gas atmosphere in the bottom and top portion of the bag was measured on Day 2, Day 3, and Day 4 post 1-MCP treatment with the results given in Table 3.

[0112] The desired oxygen concentration in the atmosphere of the bag was 5.5% to 11.5% by weight. The oxygen concentration in the bottom of the bag for Comparative Examples C1 to C4 was unacceptably low. Also, Comparative Examples C3 and C4 had anaerobic characteristics present in the banana taste.

TABLE-US-00001 TABLE 1A Film Composition Anti- Tube Width Thickness Example PE EVA Slip Block cm (inch) micrometer (mil) C1 69% 20% 6% 5% 91.4 (36) 26.9 (1.06) C2 79% 12% 4% 5% 91.4 (36) 26.4 (1.04) C3 79% 12% 4% 5% 99.1 (39) 27.9 (1.10) C4 71% 20% 4% 5% 99.1 (39) 26.9 (1.06)
Amounts shown are by weight based on the weight of the film.

TABLE-US-00002 TABLE 1B Film Properties Tensile Toughness MD Example PO2 PCO2 MPa (psi) C1 7,640 40,900 61.81 (8965) C2 9,100 45,400 56.95 (8260) C3 8,820 44,600 59.92 (8690) C4 7,890 41,400 58.12 (8430)

TABLE-US-00003 TABLE 2A Film Perforation Details Spacing of perforations, Diameter of perforations, Example mm micrometers C1 5.43 114.0 C2 5.44 117.8 C3 5.49 109.1 C4 5.48 101.5

TABLE-US-00004 TABLE 2B Further Film Perforation Details Bottom Top P- S- P- P- S- P- P- Example Area Area Density Area Area Density Ratio C1 6.88 0.836 8.2 13.75 1.67 8.2 1.00:1 C2 7.33 0.836 8.8 14.66 1.67 8.8 1.00:1 C3 6.23 0.906 6.9 12.46 1.81 6.9 1.00:1 C4 5.40 0.906 6.0 10.80 1.81 6.0 1.00:1

TABLE-US-00005 TABLE 3 Gas Atmosphere Data for Comparative Examples 1 to 4. Average Average Average Average Carbon Carbon Oxygen Oxygen Minimum Dioxide Dioxide Conc. Conc. Oxygen Conc. Conc. on Day on Day Conc. on Day on Day 2, 3, & 4; 2, 3, & 4; Bottom 2, 3, & 4; 2, 3, & 4; Example Bottom Top and Day Bottom Top C1 5.3% 9.2% 4.9% 15.3% 9.7% Day 4 C2 5.1% 8.8% 4.3% 15.0% 10.3% Day 4 C3 2.1% 8.0% 2.2% 22.9% 12.0% Day 3 C4 2.4% 7.6% 2.4% 22.6% 12.4% Day 3

INVENTION EXAMPLES 1 to 4

[0113] Dual Chamber Bag In Country Packaging

[0114] A mono layer film for Invention Examples 1 through Invention Example 4 was produced by extruding a 99.7 cm (39.25 inch) diameter tube on a conventional film line. The composition of the film and the film properties are provided in Table 4A and 4B. The tube film was sealed and scored for tear off on the film line to produce bags on a roll. The tube film was perforated using a beam compression laser perforation system in the pattern shown in FIG. 2 and as detailed in Table 5A and 5B. Distances were as follows:

TABLE-US-00006 from to distance (cm) left side 15 of bag L line 9 7.37 left side 15 of bag L line 10 12.45 right side 16 of bag L line 14 6.35 right side 16 of bag L line 13 11.68 right side 16 of bag L line 12 33.27 right side 16 of bag L line 11 66.55

[0115] The perforation area is in units of mm.sup.2; for the bottom 45.7 cm (18 inches) length of the bag and for the top 91.4 cm (36 inches) length of the bag is given in Table 5. The short lanes of perforations at the bottom of the bag were indexed using an eyespot on the bag and an eyespot reader on the perforation machine. The perforated bags were used to package bananas in Guatemala in the conventional manner as shown in FIG. 1 and shipped to the United States for ripening. The bananas were ripened using a conventional 5 day ripening cycle as above and then treated with 1000 ppb of 1-MCP as above on Day 5. The bananas were then removed from the ripening room and stored at 21.7? C. (71? F.). The gas atmosphere in the bottom and top portion of the bag was measured on Day 2, Day 3, and Day 4 post 1-MCP treatment with the results given in Table 6.

[0116] The oxygen concentration for the bottom 45.7 cm (18 inches) of the banana bag is above the desired target of 5.5% or higher while the oxygen concentration in the top 91.4 cm (36 inches) of the banana bag is within the target of 11.5% or lower.

TABLE-US-00007 TABLE 4A Film Composition for Invention Examples 1 to 4 Anti- Thick-ness; Example PE EVA Slip Block PPA micrometer (mil) 1 69% 20% 4% 5% 2% 27.4 (1.08) 2 69% 20% 4% 5% 2% 27.4 (1.08) 3 69% 20% 4% 5% 2% 27.4 (1.08) 4 69% 20% 4% 5% 2% 27.4 (1.08)

TABLE-US-00008 TABLE 4B Film Properties for Invention Examples 1 to 4 Tensile Toughness; MD Example PO2 PCO2 MPa (psi) 1 7,920 45,700 52.06 (7,550) 2 7,920 45,700 52.06 (7,550) 3 7,920 45,700 52.06 (7,550) 4 7,920 45,700 52.06 (7,550)

TABLE-US-00009 TABLE 5A Film Perforation Details for Invention Examples 1 to 4 Full Lane Short Lane Full Lane Perforation Short Lane Perforation Perforation Diameter; Perforation Diameter; Example Spacing; mm micrometer Spacing; mm micrometer 1 5.418 110.2 4.81 116.9 2 5.439 110.2 3.857 116.9 3 5.424 110.2 2.686 116.9 4 6.040 110.2 3.392 114.8

TABLE-US-00010 TABLE 5B Further Film Perforation Details for Invention Examples 1 to 4 Bottom Top P- S- P- P- S- P- P- Example Area Area Density Area Area Density Ratio 1 10.48 0.906 11.6 12.88 1.81 7.1 1.6:1 2 11.44 0.906 12.6 12.83 1.81 7.1 1.8:1 3 13.71 0.906 15.1 12.86 1.81 7.1 2.1:1 4 11.29 0.906 12.5 11.55 1.81 6.4 2.0:1

TABLE-US-00011 TABLE 6 Gas Atmosphere Data for Invention Examples 1 to 4. Av Oxygen Av Oxygen Av Carbon Av Carbon Conc. Day Conc. Day Dioxide Conc. Dioxide Conc. 2, 3, & 4; 2, 3, & 4; Day 2, 3, & 4; Day 2, 3, & 4; Example Bottom Top Bottom Top 1 5.8% 11.0% 14.7% 9.1% 2 6.4% 11.2% 14.5% 8.7% 3 5.7% 10.2% 15.0% 12.6% 4 6.3% 9.1% 14.6% 10.5%