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 at least 20% of biobased polyethylene and further comprises an odor barrier polymer.

2. The multilayer film according to claim 1, where the odor barrier polymer is EVOH.

3. The multilayer film according to claim 1, where the film comprises two outer polymer at least one of which comprising biobased polyethylene.

4. The multilayer film according to claim 1, wherein the film contains polypropylene.

5. The multilayer film according to claim 1, wherein the total amount of substantially non-resilient material in the film is 50% per weight or less.

6. The multilayer film according to claim 2, wherein the total amount of substantially non-resilient material in each outer layer is 50% per weight or less, .

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

8. The multilayer film according to claim 3, wherein the weight of each outer layer is less than 8 g/m.sup.2.

9. The multilayer film according to claim 1 wherein the biobased polyethylene is in blend with an ethylene alpha F.

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

11. The multilayer film according to claim 3, wherein at least one or both of the outer layers comprise a slip agent, preferably, the slip agent is an amide-based slip agent.

12. The multilayer film according to claim 3 wherein both outer layers have a kinetic film-to-film coefficient of friction of less than 0.35 measured according to ASTMD1894.

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

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

15. The multilayer film according to claim 3, 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.

16. The multilayer film according to claim 3,wherein at least one of the outer layers, preferably both outer layers, additionally comprises 0.5-40% per weight, low density polyethylene (LDPE) based on the total weight of the corresponding outer layer.

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

18. Use of the multilayer film according to claim 1 for waste packing.

19. Use of the multilayer film according to claim 18, wherein the film is stored in a cassette.

20. Use of the multilayer film according to claim 18, wherein the film is folded or the film is in the form of a bag.

Description

DETAILED DESCRIPTION

[0069] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0070] According to a first aspect the present invention is directed to a multilayer film with weight less than 20 g/m.sup.2 for use in malodorous item packaging, where the film comprises two outer layers comprising ethylene alpha olefin copolymers.

[0071] In a preferred embodiment the multilayer film comprises, preferably consists of the following layers: OUTER LAYER / INTERMEDIATE LAYER 1 / INTERMEDIATE LAYER 2 / BARRIER LAYER / INTERMEDIATE LAYER 3 / INTERMEDIATE LAYER 4 / OUTER LAYER wherein each of INTERMEDIATE LAYER 1-4 can comprise the same or different materials.

[0072] In a preferred embodiment the multilayer film comprises, preferably consists of the following layers: OUTER LAYER / INTERMEDIATE LAYER 1 / BARRIER LAYER / INTERMEDIATE LAYER 3 / OUTER LAYER wherein INTERMEDIATE LAYER 1 and 3 can comprise the same or different materials.

Detailed Description of Layers

Barrier Layer

[0073] Preferably, the multilayer film comprises an odor barrier layer.

[0074] In one embodiment the barrier layer comprises EVOH as an odor barrier material.

[0075] 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.

[0076] In another embodiment the barrier layer comprises polyamide as a barrier material.

[0077] The oxygen barrier material preferably has a weight of less than 5 g/m2, more preferably less than 4 g/m2 , even more preferably less than 2.5 g/m2.

Outer Layers

[0078] The outer layer comprises preferably at least 20% of biobased polyethylene. In a preferred version, both outer layer comprises at least 50% biobased polyethylene.

[0079] The biobased polyethylene is preferably low density polyethylene, ethylene alpha olefin copolymer, medium density polyethylene and/or high density polyethylene.

[0080] In a preferred embodiment the biobased polyethylene is used in blend with ethylene alpha olefin copolymer, preferably butene, hexene or octene copolymer.

[0081] 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.

[0082] In a further preferred embodiment at least one of the outer layers comprises high density polyethylene.

[0083] In a further preferred version, the weight of each outer layer is less than 8 g/m2, preferable less than 6 g/m2, more preferably less than 5 g/m2.

[0084] The total amount of substantially non-resilient material in each outer layer is preferably 50% per weight or less, more preferably 40% per weight or less, even more preferably 30% per weight or less.

[0085] 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).

[0086] 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.

[0087] 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.

Intermediate Layers

[0088] 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.

[0089] 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.

[0090] In another preferred version of the invention, an intermediate layer comprises a polyamide. For example, a preferred version of the invention is: [0091] Outer layer / Intermediate layer 1 / Intermediate layer 2 / EVOH / polyamide / Intermediate layer 3 / Outer layer or [0092] Outer layer / Intermediate layer 1 / Polyamide / EVOH / Polyamide / Intermediate layer 3 / Outer layer

[0093] In another version of the invention, at least one intermediate layer comprises polyamide.

[0094] If a multilayer film of the present invention comprises polyamide in an intermediate layer, then preferably polyamide 6 or polyamide 6/66 is used.

[0095] In another preferred version of the invention the adhesive tie layers are compounds of biobased polyethylene eg with maleic anhydride.

General

[0096] 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.

[0097] The antimicrobial/antibacterial additive preferably comprises silver, silver ion and/or copper. More preferably it comprises silver ion.

[0098] 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.

[0099] In a preferable version of the invention the film comprises polypropylene, more preferable biobased polypropylene.

[0100] The total amount of substantially non-resilient material in the multilayer film is preferably 30% per weight or less, more preferably 20% per weight or less.

[0101] The total amount of substantially non-resilient material in each outer layer is preferably 30% per weight or less, more preferably 20% per weight or less.

[0102] 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.

[0103] In order to increase the mechanical properties, the film may be crosslinked with one of the following methods. E-beam radiation, gamma radiation, moisture crosslinking using silane grafting compounds, peroxide crosslinking.

[0104] 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 US 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.

[0105] 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.

[0106] In a preferable embodiment the film is stored in a cassette prior to use, e.g. a cassette as described in US 4,934,529.

[0107] 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 US 4,934,529 is used.

[0108] 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.

[0109] In a preferable embodiment the film is stored in a cassette prior to use, e.g. a cassette as described in US 4,934,529.

EXAMPLES

[0110] A 5-layer film is produced in a commercial hot blown film line with the following recipe: [0111] Outer layer 1, 70% biobased polyethylene+ 25% EAO1+ 5% erucamide based slip masterbatch [0112] Intermediate layer 100% ADH 1 [0113] Barrier layer EVOH 1 [0114] Intermediate layer 100% ADH1 [0115] Outer layer 2 80% HDPE+ 15% EAO1+ 5% erucamide based slip masterbatchSee table 1

[0116] The thickness of the structure is 7.5/1.5/1.5/1.5/6 starting from the outer layer1 and going to the outer layer 2.

TABLE-US-00001 Type Description Density g/cm3 Biobased PE Ethylene hexene copolymer 0.918 EAO1 Ethylene hexene copolymer produced with metallocene catalysts 0.918 ADH1 LLDPE mod. Adhesive tie 0.92 EVOH 1 EVOH with 32% ethylene 1.19 EVOH2 EVOH with 29% ethylene 1.2 SLIP Erucamide slip masterbatch comprising 5% erucamide HDPE High density polyethylene 0.952

[0117] The weight of the film is 17.1 g/m2.

Example 2

[0118] A 5-layer film is produced in a hot blown film commercial line with the following recipe: [0119] Outer layer 1, 95% biobased PE+ 5% erucamide based SLIP masterbatch [0120] Intermediate layer 100% ADH 1 [0121] Barrier layer EVOH 1 [0122] Intermediate layer 100% ADH1 [0123] Outer layer 2 95% biobased PE+ 5% erucamide based SLIP masterbatch

[0124] 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.

[0125] The weight of the material is 15.102 g/m2.

Example 3

[0126] A 5-layer film is produced in a hot blown film commercial line with the following recipe: [0127] Outer layer 1, 95% biobased PE+ 5% erucamide based SLIP masterbatch [0128] Intermediate layer 100% ADH 1 [0129] Barrier layer EVOH 2 [0130] Intermediate layer 100% ADH1 [0131] Outer layer 2, 95% biobased PE+ 5% erucamide based SLIP masterbatch

[0132] The thickness of the structure is 3/1.5/1.5/1.5/3 starting from the outer layer 1 and going to the outer layer 2.

[0133] The weight of the material is 10.068 g/m2.

[0134] The difference between examples 1, 2 on one hand and example 3 on the other hand is that in examples 1, 2 a biobased polyethylene produced by wood residue was used while in example 3 a biobased polyethylene produced by cooked oil residue was used. Both biobased Pes were of the same density and chemical structure.

Comparative Example 1

[0135] A 5-layer film is produced in a hot blown film commercial line with the following recipe: exactly same as example 1 but the biobased PE is replaced by the same grade PE from fossil fuel building blocks.

Comparative Example 2

[0136] A 5-layer film is produced in a hot blown film commercial line with the following recipe : exactly same as example 3 but the biobased PE is replaced by the same grade PE from fossil fuel building blocks.

Tests

[0137] 1. Processing testing of the downgage behavior of the film [0138] 2. Compression testing

Test 1

[0139] It was surprisingly found that the examples comprising polyethylene of biobased content are easier to downgage to the very low film thicknesses as required by the application.

[0140] More specifically the number of bubble bursts (i.e. bubble is collapsing and the extrusion process is interrupted) was monitored per each case. Reference was 10 hours of steady production during which the blown film behavior was watched and the bubble bursts were recorded. [0141] Example 1, faced 1 bubble burst in 10 hours steady production [0142] Example 2, faced 0 bubble burst [0143] Example 3, faced 0 [0144] Comparative example 1 faced 4 bubble bursts [0145] Comparative example 2 faced 5 bubble bursts

Compression Testing

[0146] A paper core of diameter 76 mm and height 50 cm was used in order to test compression.

[0147] 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).

[0148] By completing the test it was obvious that the result of the testing is the same independently of the biobased or not biobased sourcing of the polyethylene.

[0149] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.