Thin film for waste packing cassettes

Abstract

The present invention refers to a polymeric film comprising odor barrier material and being able to pack malodorous waste.

Claims

1. A multilayer film with weight less than 20 g/m.sup.2 for use in malodorous item packaging, wherein the film comprises two outer layers, wherein at least one of the outer layers comprise at least 50% per weight high density polyethylene (HDPE) based on the total weight of the corresponding layer, wherein the HDPE is in a blend with an ethylene alpha olefin copolymer, wherein the film comprises at least one barrier layer comprising EVOH, and wherein the film does not contain polypropylene.

2. The multilayer film according to claim 1, wherein both outer layers comprise at least 50% per weight high density polyethylene (HDPE).

3. The multilayer film according to claim 1, wherein the ethylene alpha olefin copolymer, is a hexene or octene copolymer.

4. The multilayer film according to claim 1, wherein the film comprises or consists of the following layers: OUTER LAYER / INTERMEDIATE LAYER 1 /BARRIER LAYER / INTERMEDIATE LAYER 3 /OUTER LAYER.

5. The multilayer film according to claim 1, wherein the film comprises or consists of the following layers: OUTER LAYER / INTERMEDIATE LAYER 1 /INTERMEDIATE LAYER 2 /BARRIER LAYER / INTERMEDIATE LAYER 3 /INTERMEDIATE LAYER 4 /OUTER LAYER.

6. The multilayer film according to claim 1, wherein the film presents an antibacterial activity characterized by a decline of at least 20% of the population of Staphylococcus aureus held in contact with at least one of the outer layers of the film for 24 hours compared to the initial population, measured according to ISO 2196/2011 for measurement of the antibacterial activity on plastics and other non-porous surfaces.

7. The multilayer film according to claim 1, wherein a total amount of a substantially non-resilient material in the film is 30% per weight or less.

8. The multilayer film according to claim 7, wherein the total amount of substantially non-resilient material in the film is 25% per weight or less.

9. The multilayer film according to claim 7, wherein the total amount of substantially non-resilient material in the film is 20% per weight or less.

10. The multilayer film according to claim 1, wherein a total amount of a substantially non-resilient material in each outer layer is 50% per weight or less.

11. The multilayer film according to claim 10, wherein the total amount of substantially non-resilient material in each outer layer is 40% per weight or less.

12. The multilayer film according to claim 10, wherein the total amount of substantially non-resilient material in each outer layer is 30% per weight or less.

13. The multilayer film according to claim 1, wherein the film has a weight less than 18 g/m.sup.2.

14. The multilayer film according to claim 13, wherein the film has a weight less than 17 g/m.sup.2.

15. The multilayer film according to claim 13, wherein the film has a weight less than 16 g/m.sup.2.

16. The multilayer film according to claim 13, wherein the film has a weight less than 15 g/m.sup.2.

17. The multilayer film according to claim 13, wherein the film has a weight less than 14 g/m.sup.2.

18. The multilayer film according to claim 13, wherein the film has a weight less than 13 g/m.sup.2.

19. The multilayer film according to claim 1, wherein the weight of each outer layer is less than 8 g/m.sup.2.

20. The multilayer film according to claim 19, wherein the weight of each outer layer is less than 6 g/m.sup.2.

21. The multilayer film according to claim 19, wherein the weight of each outer layer is less than 5 g/m.sup.2.

22. The multilayer film according to claim 1, wherein the film further comprises at least one intermediate layer comprising polyamid.

23. The multilayer film according to claim 22, wherein the polyamide is polyamide 6 or polyamide 6/66.

24. The multilayer film according to claim 1, wherein at least one or both of the outer layers comprise a slip agent.

25. The multilayer film according to claim 24, wherein the slip agent is an amide-based slip agent.

26. The multilayer film according to claim 1, wherein both outer layers have a kinetic film-to-film coefficient of friction of less than 0.35 measured according to ASTMD1894.

27. The multilayer film according to claim 26, wherein the coefficient of friction is less than 0.30.

28. The multilayer film according to claim 26, wherein the coefficient of friction is less than 0.25.

29. The multilayer film according to claim 26, wherein the coefficient of friction is less than 0.2.

30. The multilayer film according to claim 1, wherein at least one of the outer layer additionally comprises 0.5-40% per weight low density polyethylene (LDPE) based on the total weight of the corresponding outer layer.

31. The multilayer film according to claim 30, wherein both outer layers additionally comprise 0.5-40% per weight low density polyethylene (LDPE) based on the total weight of the corresponding outer layer.

32. The multilayer film according to claim 30, wherein at least one of the outer layers comprises 5-30% per weight low density polyethylene (LDPE) based on the total weight of the corresponding outer layer.

33. The multilayer film according to claim 30, wherein both outer layers comprise 5-30% per weight low density polyethylene (LDPE) based on the total weight of the corresponding outer layer.

34. A cassette comprising a film according to claim 1, for use in waste packaging applications.

35. A method of packing waste, comprising packing waste in the multilayer film according to claim 1.

36. The method according to claim 35, wherein the film is stored in a cassette.

37. The method according to claim 35, wherein the film is folded or the film is in the form of a bag.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) According to a first aspect the present invention is directed to a multilayer film with weight less than 20g/m.sup.2 for use in malodorous item packaging, where the film comprises two outer layers comprising ethylene alpha olefin copolymers.

(2) In a preferred embodiment the multilayer film comprises, preferably consists of the following layers:

(3) OUTER LAYER/INTERMEDIATE LAYER 1/INTERMEDIATE LAYER 2/BARRIER LAYER/INTERMEDIATE LAYER 3/INTERMEDIATE LAYER 4/OUTER LAYER

(4) Wherein each of INTERMEDIATE LAYER 1-4 can comprise the same or different materials.

(5) In a preferred embodiment the multilayer film comprises, preferably consists of the following layers:

(6) OUTER LAYER/INTERMEDIATE LAYER 1/BARRIER LAYER/INTERMIDIATE LAYER 3/OUTER LAYER

(7) Wherein INTERMEDIATE LAYER 1 and 3 can comprise the same or different materials.

(8) Detailed description of layers

(9) Barrier layer

(10) Preferably, the multilayer film comprises a barrier layer.

(11) In one embodiment the barrier layer comprises EVOH as a barrier material.

(12) The EVOH used preferably has an ethylene content less than 48%, more preferably less than 44%, more preferably less than 38%, more preferably from 27 to 32% ethylene.

(13) In another embodiment the barrier layer comprises polyamide as a barrier material.

(14) The oxygen barrier material preferably has a weight of less than 5 g/m.sup.2, more preferably less than 4 g/m.sup.2, even more preferably less than 2.5 g/m.sup.2.

(15) Outer Layers

(16) The outer layer comprises preferably at least 50% per weight high density polyethylene (HDPE). In a preferred version, both outer layer comprises at least 50% per weight high density polyethylene (HDPE).

(17) In a preferred embodiment the HDPE is used in blend with ethylene alpha olefin copolymer, preferably hexene or octene copolymer.

(18) In a further preferred embodiment at least one of the outer layers, preferably both outer layers, additionally comprises 0.5-40%, preferably 5-30% per weight low density polyethylene (LDPE) based on the total weight of the corresponding outer layer.

(19) In a further preferred version, the weight of each outer layer is less than 8 g/m.sup.2, preferable less than 6 g/m.sup.2, more preferably less than 5 g/m.sup.2.

(20) In a preferred version, at least one or both of the outer layer comprise a slip agent, preferably, the slip agent is an amide-based slip agent (lubricant).

(21) Slip agents are preferable of the amide family, such as erucamide, oleamide, oleyl-palmitamide, stearamide, behenamide and the like. Alternatively, the slip may also comprise silicon or siloxane materials.

(22) In a further preferred version of the invention the kinetic coefficient of friction of each of the two outer layers measured upon itself (as per ASTMD1894) is less than 0.35, more preferably less than 0.3, even more preferably less than 0.25, most preferably less than 0.2.

(23) Intermediate Layers

(24) In a preferred embodiment, the multilayer film comprises at least one intermediate layer. The multilayer film can comprise several intermediates layers. Preferably the intermedial layer(s) is (are) located between the barrier layer and one of the outer layers. There can be more than one intermediate layer be located between the barrier layer and one of the outer layers.

(25) In the intermediate layers, typical adhesive resins like maleic anhydrite modified polyolefins may be used. Typical examples are BYNEL from Dupont and OREVAC from Arkema.

(26) In another preferred version of the invention, an intermediate layer comprises a polyamide. For example, a preferred version of the invention is Outer layer/Intermediate layer 1/Intermediate layer 2/EVOH/polyamide/Intermediate layer 3/Outer layer or

(27) Outer layer/Intermediate layer 1/Polyamide/EVOH/Polyamide/Intermediate layer 3/Outer layer

(28) In another version of the invention, at least one intermediate layer comprises polyamide.

(29) If a multilayer film of the present invention comprises polyamide in an intermediate layer, then preferably polyamide 6 or polyamide 6/66 is used.

(30) General

(31) Additives well known in the art may be used in one or more layers of the present invention. Slip additives, antifog additives, polymer processing aids may be used if pertinent. Antimicrobial and/or antibacterial additives may also be used in one or more of the layers to inhibit the microbe formation. Preferably the antimicrobial or antibacterial additive is added to at least one, or both outer layers. Preferably the antimicrobial or antibacterial additive is added to the outer layer in direct contact to the product to be packed.

(32) The antimicrobial/antibacterial additive preferably comprises silver, silver ion and/or copper. More preferably it comprises silver ion. The additive may be used in an amount of from 0.2 to 20% per weight of the corresponding layer wherein the additive is added.

(33) In a preferable version of the invention the film does not comprise polypropylene.

(34) The total amount of substantially non-resilient material in the multiplayer film is preferably 10% per weight or less, more preferably 7% per weight or less, even more preferably 5% per weight or less, in particular 3% per weight or less, based on the total weight of the multilayer film. Most preferably the multilayer-film does not contain any substantially non-resilient material.

(35) The total amount of substantially non-resilient material in each outer layer is preferably 10% per weight or less, more preferably 7% per weight or less, even more preferably 5% per weight or less, in particular 3% per weight or less, based on the total weight of the corresponding outer layer. Most preferably each outer layer does not contain any substantially non-resilient material.

(36) In a preferable version of the invention the film presents an antibacterial activity as follows; a decline of at least 20% of the population of Staphylococcus aureus held in contact with at least one of the outer layers of the film for 24 hours compared to the initial population. The measurements are made as per ISO 2196/2011 measurement of the antibacterial activity on plastics and other non-porous surfaces.

(37) In order to increase the mechanical properties, the film may be cross-linked with one of the following methods. E-beam radiation, gamma radiation, moisture crosslinking using silane grafting compounds, peroxide crosslinking.

(38) The film may be in tubular form or sealed at the edges or single sheet configuration. It may also be folded once or many times (as per U.S. Pat. No. 5,037,370 for example). It can also be used in the form of a series of bags, gusseted or non-gusseted, folded or not folded. Centerfold configuration is also possible.

(39) The preferred production method for the film is the hot blown film method, which is well known in the art. Other methods like extrusion through flat cast die is also possible.

(40) In a preferable embodiment the film is stored in a cassette prior to use, e.g. a cassette as described in U.S. Pat. No. 4,934,529.

(41) According to a second aspect the present invention is directed to a cassette comprising a film according to the present invention for use in waste packaging applications. In a preferable embodiment a cassette as described e.g. in U.S. Pat. No. 4,934,529 is used.

(42) According to a third aspect the present invention is directed to the use of a multilayer film according to the present invention for waste packing, wherein the film is preferably stored in a cassette.

(43) In a preferable embodiment the film is stored in a cassette prior to use, e.g. a cassette as described in U.S. Pat. No. 4,934,529.

(44) Mechanical Properties

(45) The film of the present application despite its low thickness is very good in mechanical properties such as tensile strength and elongation as per ASTM D882.

(46) In a preferred version of the invention the film has a tensile strength at break of at least 20 N/MM2 in at least one of machine and transverse direction and an elongation of at least 300% in at least one of machine and transverse directions.

EXAMPLES

(47) A 5-layer film is produced in a commercial hot blown film line with the following recipe

(48) Outer layer 1, 80% HDPE+ 15% EAO1+ 5% erucamide based slip masterbatch

(49) Intermediate layer 100% ADH 1

(50) Barrier layer EVOH 1

(51) Intermediate layer 100% ADH1

(52) Outer layer 2 80% HDPE+ 15% EAO+ 5% erucamide based slip masterbatch

(53) See table 1

(54) The thickness of the structure is 7.5/1.5/1.5/1.5/6 starting from the outer layer 1 and going to the outer layer 2.

(55) TABLE-US-00001 TABLE 1 Density Type Description g/cm.sup.3 HDPE HDPE homopolymer 0.952 EAO1 Ethylene hexene copolymer produced with 0.918 metallocene catalysts ADH1 LLDPE mod. Adhesive tie 0.92 EVOH 1 EVOH with 32% ethylene 1.19 EVOH2 EVOH with 29% ethylene 1.2 SNR 1 Calcium carbonate polyethylene compound 1.7 LDPE Low density polyethylene of density 0.924 and MFI 0.7 at 190 c., 2.16 KG SLIP Erucamide slip masterbatch comprising 5% erucamide PA1 Polyamide 6/66 1.13

(56) The weight of the film is 17.3 g/m2.

Example 2

(57) A 5-layer film is produced in a hot blown film commercial line with the following recipe

(58) Outer layer 1, 95% HDPE+5% erucamide based SLIP masterbatch

(59) Intermediate layer 100% ADH 1

(60) Barrier layer EVOH 1

(61) Intermediate layer 100% ADH1

(62) Outer layer 2 95% HDPE+ 5% erucamide based SLIP masterbatch

(63) The thickness of the structure is 6.5/1.5/1.5/1.5/5 starting from the outer layer 1 and going to the outer layer 2.

(64) The weight of the material is 15.4 g/m2.

Example 3

(65) A 5-layer film is produced in a hot blown film commercial line with the following recipe

(66) Outer layer 1, 95% HDPE+ 5% erucamide based SLIP masterbatch

(67) Intermediate layer 100% ADH 1

(68) Barrier layer PA1

(69) Intermediate layer 100% ADH1

(70) Outer layer 2 95% HDPE+5% erucamide based SLIP masterbatch

(71) The thickness of the structure is 3/1.5/1.5/1.5/2 starting from the outer layer 1 and going to the outer layer 2.

(72) The weight of the material is 10.9 g/m2.

Comparative Example

(73) A 5-layer film is produced in a hot blown film commercial line with the following recipe

(74) Outer layer 1, 65% EAO1+ 30% SNR 1+ 5% erucamide based SLIP masterbatch

(75) Intermediate layer 100% ADH 1

(76) Barrier layer EVOH 2

(77) Intermediate layer 100% ADH1

(78) Outer layer 2 65% EAO1+ 30% SNR1+ 5% erucamide based SLIP masterbatch

(79) The thickness of the structure is 5/1.5/1.5/1.5/3 starting from the outer layer 1 and going to the outer layer 2.

(80) The weight of the material is 12.1 g/m2.

(81) Tests

(82) 1. Tensile strength and elongation test is done according to ASTM D 882.

(83) 2. Compression testing

(84) Test 1.

(85) Tensile strength and elongation are measured as per ASTM D882. MD stands for machine direction, whereas TD stands for transverse direction.

(86) TABLE-US-00002 TENSILE ELONGA- TENSILE ELONGA- EXAM- STRENGTH TION STRENGTH TION PLE (MD) (MD) (TD) (TD) 1 34 270 30 385 2 37 245 30 365 3 39 260 28 355
Compression Testing

(87) A paper core of diameter 76 mm and height 50 cm was used in order to test compression.

(88) Around the diameter of paper core, a tubular film was placed and squeezed. The film length was measured so that the film did not overpass the upper end of the core. This test represents how easy is to put the tubular film in the cassette (so the number of film meters that can be squeezed inside).

(89) For the comparative film comprising high amounts of SNR 7.2 meter could be used while for the films according to the invention 7.5 (film 1), 7.8 (film 2) and 8.2 (film 3) could be used.

(90) Therefore, the ability of the innovative film to compress is better than the one of the film of prior art.

(91) Coefficient of Friction

(92) Coefficient of friction (COF) was measured as per ASTM D1894 (kinetic, film to film).

(93) The comparative film has a COF of more than 0.3 at both outer layers, while the films of the invention had values of less than 0.25.