Flex-crack resistant and thermally resistant aseptic bulk bags for flexible packaging

Patent metadata

Field	Value
Publication number	US-11254109-B2
Application number	US-202117182913-A
Country	US
Kind code	B2
Filing date	Feb 23, 2021
Priority date	Nov 14, 2017
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

This invention relates to inner-plies for bulk-bags that surprisingly offer not only high thermal resistance, but also high flex-crack resistance. This invention also relates to such bulk-bags made for packaging of flowable materials, aseptic or otherwise, and the process for improving their flex-crack and thermal resistance. Preferably, the packaging is aseptic. More specifically, the inner-ply of the invention comprises a resin blend comprising the Exceed® XP resin; an LDPE resin or an ethylene—α-olefin copolymer (EAO copolymer); or a blend of said LDPE resin and said EAO copolymer, with flex-crack resistance improved in both machine direction and transverse direction, in conjunction with an improved thermal resistance. Thus, in addition to possessing good flex-crack resistance, the bulk-bags can withstand steam sterilization and/or aseptic packaging conditions.

First claim

What is claimed is:

1. A flex-crack resistant, and thermally resistant bag for aseptic packaging of flowable materials, wherein said bag comprises at least one ply, wherein said at least one ply comprises a film made from a resin blend comprising:
(a) at least 60% of a resin comprising an ethylene-hexene-1 copolymer and an ethylene-α-olefin copolymer blend having a density range from 0.914 to 0.918 g/cm 3 and a melt index range of 0.20 to 1.0 dg/min; and
(b) one of the following three components:
(i) from 0-40% of LDPE;
(ii) from 0-40% of EAO copolymer; and
(iii) from 0-40% of a blend of LDPE and said EAO copolymer;

wherein said resin blend comprises an overall density of at least 0.915 g/cm 3 ; and
wherein said bag has flex-crack resistance such that said film develops less than 10 pinholes per 300 cm 2 in 8,100 cycles in both machine direction and transverse direction in a Gelbo Flex Test as measured according to ASTM F392, wherein the HDPE peak-melting endotherm as percentage of the total melting endotherm, in a DSC measurement, of the resin blend is in the range of from about 40 to about 60.

2. The bag according to claim 1 , comprising at least two plies, wherein one of the at least two plies comprises an outer, or skin layer, comprising a film made from a resin blend comprising:
(a) at least 60% of a resin comprising an ethylene-hexene-1 copolymer and an ethylene-α-olefin copolymer blend having a density range from 0.914 to 0.918 g/cm 3 and a melt index range of 0.20 to 1.0 dg/min; and
(b) one of the following three components:
(i) from 0-40% of LDPE;
(ii) from 0-40% of EAO copolymer; and
(iii) from 0-40% of a blend of LDPE and said EAO copolymer;

wherein said resin blend comprises an overall density of at least 0.915 g/cm 3 ; and
wherein said bag has flex-crack resistance such that said film develops less than 10 pinholes per 300 cm 2 in 8,100 cycles in both machine direction and transverse direction in a Gelbo Flex Test as measured according to ASTM F392, wherein the HDPE peak-melting endotherm as percentage of the total melting endotherm, in a DSC measurement, of the resin blend is in the range of from about 40 to about 60.

3. The bag according to claim 1 , wherein the EAO copolymer content is up to 40%.

4. The bag according to claim 1 , wherein the size of said bag ranges from 2 gallons to 20 gallons.

5. The bag according to claim 1 , wherein said at least one ply has a thickness in the range of 20 μm to 140 μm thickness.

6. The bag according to claim 1 , comprising flowable material.

7. The bag according to claim 1 , wherein said bag is a steam-sterilization bag for aseptic processes, an ESL, hot-fill, or pasteurization bag.

8. The bag according to claim 1 , wherein the HDPE peak-melting endotherm as percentage of the total melting endotherm, in a DSC measurement, of the resin blend is in the range of from about 50 to about 60.

9. The bag according to claim 1 , wherein said film develops less than 5 pinholes per 300 cm 2 in 8,100 cycles in both machine direction and transverse direction in a Gelbo Flex Test as measured according to ASTM F392.

10. The bag according to claim 9 , wherein the LDPE content is in the range of from about 5% to about 20%.

11. The bag according to claim 10 , wherein the LDPE content is in the range of from about 10% to about 15%.

12. The bag according to claim 10 , wherein said EAO copolymer is a butene-LLDPE resin, in a density range of from about 0.818-0.922 g/cm 3 .

13. The bag according to claim 1 , wherein the bag further comprises a structure having from 3-7 layers, and wherein at least one of the layers comprises a barrier layer.

14. The bag according to claim 13 , wherein the barrier layer comprises PET or met-PET.

15. A process for making a bag, comprising:
(I) providing at least one ply, wherein said at least one ply comprises a film made from a resin blend comprising:
(a) at least 60% of a resin comprising an ethylene-hexene-1 copolymer and an ethylene-α-olefin copolymer blend having a density range from 0.914 to 0.918 g/cm 3 and a melt index range of 0.20 to 1.0 dg/min; and
(b) one of the following three components:
(i) from 0-40% of LDPE;
(ii) from 0-40% of EAO copolymer; and
(iii) from 0-40% of a blend of LDPE and said EAO copolymer;

wherein said resin blend comprises an overall density of at least 0.915 g/cm 3 ; and
wherein said bag has flex-crack resistance such that said film develops less than 10 pinholes per 300 cm 2 in 8,100 cycles in both machine direction and transverse direction in a Gelbo Flex Test as measured according to ASTM F392, wherein the HDPE peak-melting endotherm as percentage of the total melting endotherm, in a DSC measurement, of the resin blend is in the range of from about 40 to about 60.

16. The process according to claim 15 , comprising:
(I) providing at least two plies, wherein one of the at least two plies comprises an outer, or skin layer, comprising a film made from a resin blend comprising:
(a) at least 60% of a resin comprising an ethylene-hexene-1 copolymer and an ethylene-α-olefin copolymer blend having a density range from 0.914 to 0.918 g/cm 3 and a melt index range of 0.20 to 1.0 dg/min; and
(b) one of the following three components:
(i) from 0-40% of LDPE;
(ii) from 0-40% of EAO copolymer; and
(iii) from 0-40% of a blend of LDPE and said EAO copolymer;

wherein said resin blend comprises an overall density of at least 0.915 g/cm 3 ; and
wherein said bag has flex-crack resistance such that said film develops less than 10 pinholes per 300 cm 2 in 8,100 cycles in both machine direction and transverse direction in a Gelbo Flex Test as measured according to ASTM F392, wherein the HDPE peak-melting endotherm as percentage of the total melting endotherm, in a DSC measurement, of the resin blend is in the range of from about 40 to about 60.

17. The process according to claim 15 , wherein the EAO copolymer content is up to 40%.

18. The process according to claim 15 , wherein the size of said bag ranges from from 2 gallons to 20 gallons.

19. The process according to claim 15 , wherein said at least one ply has a thickness in the range of 20 μm to 140 μm thickness.

20. The process according to claim 15 , comprising flowable material.

21. The process according to claim 15 , wherein said bag is a steam-sterilization bag for aseptic processes, an ESL, a hot-fill, or a pasteurization bag.

22. The process according to claim 15 , wherein the HDPE peak-melting endotherm as percentage of the total melting endotherm, in a DSC measurement, of the resin blend is in the range of from about 50 to about 60.

23. The process according to claim 15 , wherein said film develops less than 5 pinholes per 300 cm 2 in 8,100 cycles in both machine direction and transverse direction in a Gelbo Flex Test as measured according to ASTM F392.

24. The process according to claim 23 , wherein the LDPE content is in the range of from about 5% to about 20%.

25. The process according to claim 24 , wherein the LDPE content is in the range of from about 10% to about 15%.

26. The process according to claim 24 , wherein said EAO copolymer is a butene-LLDPE resin, in a density range of from about 0.818-0.922 g/cm 3 .

27. The process according to claim 15 , wherein the bag further comprises a structure having from 3-7 layers, and wherein at least one of the layers comprises a barrier lay

Assignees

• Liqui Box Corp

Inventors

• Farkas Nicholas

Classifications

• B32B2307/75

  Printability · CPC title

• B32B2250/242

  All polymers belonging to those covered by group B32B27/32 · CPC title

• B32B27/36

  comprising polyesters · CPC title

• B32B27/08 Primary

  of synthetic resin · CPC title

• B65D88/1606

  double-walled or with linings (B65D88/1612 takes precedence; linings for container walls in general B65D90/04) · CPC title