THIN FILM FOR WASTE PACKING CASSETTES

Abstract

The present invention relates to a multilayer film for use in malodorous item packaging, a cassette comprising such a multilayer film and the use of the multilayer film for waste packing.

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 comprising ethylene alpha olefin copolymer.

2. The multilayer film according to claim 1, wherein at least one or both of the outer layers comprise more than 50% per weight ethylene alpha olefin copolymer.

3. The multilayer film according to claim 1, wherein the film further comprises a barrier layer, preferably wherein the barrier layer comprises EVOH or polyamide.

4. The multilayer film according to claim 1, wherein the film does not contain polypropylene.

5. The multilayer film according to claim 1, wherein a total amount of substantially non-resilient material in the film is 10% per weight or less, preferably 7% per weight or less, more preferably 5% per weight or less, even more preferably 3% per weight or less, based on the total weight of the multilayer film, most preferably wherein the multilayer-film does not contain any substantially non-resilient material.

6. The multilayer film according to claim 1, wherein a total amount of substantially non-resilient material in each outer layer is 10% per weight or less, preferably 7% per weight or less, 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 wherein each outer layer does not contain any substantially non-resilient material.

7. The multilayer film according to claim 1, wherein the film has a weight less than 18 g/m.sup.2, preferably less than 17 g/m.sup.2, more preferably less than 16 g/m.sup.2, even more preferably less than 15 g/m.sup.2, most preferably less than 14 g/m.sup.2, and in particular less than 13 g/m.sup.2.

8. The multilayer film according to claim 1, wherein 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.

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

10. The multilayer film according to claim 1, wherein the film further comprises at least one intermediate layer comprising polyamide, preferably wherein the polyamide is polyamide 6 or polyamide 6/66.

11. The multilayer film according to claim 1, wherein at least one or both of the outer layers comprise a slip agent, preferably, wherein the slip agent is an amide-based slip agent.

12. 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, preferably wherein the coefficient of friction is less than 0.30, more preferably wherein the coefficient of friction is less than 0.25, even more preferably wherein the coefficient of friction is less than 0.2.

13. 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

14. 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

15. 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.

16. The multilayer film according to claim 1, wherein 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.

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

18. A method for packing waste wherein the method comprises packing waste in a multilayer film according to claim 1.

19. The method according to claim 18, wherein the film is stored in a cassette.

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

Description

DETAILED DESCRIPTION OF THE INVENTION

[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:

[0072] OUTER LAYER/INTERMEDIATE LAYER 1/INTERMEDIATE LAYER 2/BARRIER LAYER/INTERMEDIATE LAYER 3/INTERMEDIATE LAYER 4/OUTER LAYER

[0073] Wherein each of INTERMEDIATE LAYER 1-4 can comprise the same or different materials.

[0074] In a preferred embodiment the multilayer film comprises, preferably consists of the following layers:

[0075] OUTER LAYER/INTERMEDIATE LAYER 1/BARRIER LAYER/INTERMEDIATE LAYER 3/OUTER LAYER

[0076] Wherein INTERMEDIATE LAYER 1 and 3 can comprise the same or different materials.

[0077] Detailed Description of Layers

[0078] Barrier layer

[0079] Preferably, the multilayer film comprises a barrier layer.

[0080] In one embodiment the barrier layer comprises EVOH as a barrier material.

[0081] 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.

[0082] In another embodiment the barrier layer comprises polyamide as a barrier material.

[0083] The oxygen barrier material preferably has a weight of less than 3 g/m.sup.2, more preferably less than 2 g/m.sup.2 and even more preferably less than 1.5 g/m.sup.2.

[0084] Outer Layers

[0085] The outer layer comprises ethylene alpha olefin copolymer. In a preferred version, the outer layer comprises one or more ethylene alpha olefin copolymers in more than 50% weight fraction based on the total weight of the outer layer. The outer layer can further comprise in addition to the ethylene alpha olefin copolymer a low-density polyethylene, styrene polymers and/or additives. Low density polyethylene (LDPE) is preferred.

[0086] In a preferred embodiment, the multilayer film comprises in at least one of the outer layers, in addition to the ethylene alpha olefin copolymer, 0.5-40%, preferably 5-30% per weight of low-density polyethylene (LDPE) based on the total weight of the corresponding outer layer.

[0087] In a further preferred embodiment, the multilayer film comprises in both outer layers, in addition to the ethylene alpha olefin copolymer, 0.5-40%, preferably 5-30% per weight of low-density polyethylene (LDPE) based on the total weight of the corresponding outer layer.

[0088] 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.

[0089] In a further preferred version, the two outer layers comprise a slip agent (lubricant). 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 siloxane materials.

[0090] 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.

[0091] Intermediate Layers

[0092] 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.

[0093] 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.

[0094] In another preferred version of the invention, an intermediate layer comprises a polyamide. For example, a preferred version of the invention is

[0095] Outer layer/Intermediate layer 1/Intermediate layer 2/EVOH/polyamide/Intermediate layer 3/Outer layer

[0096] or

[0097] Outer layer/Intermediate layer 1/Polyamide/EVOH/Polyamide/Intermediate layer 3/Outer layer

[0098] In another version of the invention, at least one intermediate layer comprises polyamide.

[0099] If a multilayer film of the present invention comprises polyamide in an intermediate layer, then preferably polyamide 6 or polyamide 6/66 is used.

[0100] General

[0101] 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.

[0102] The antimicrobial/antibacterial additive preferably comprises silver, silver ion and/or copper. More preferably it comprises silver ion.

[0103] 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.

[0104] In a preferable version of the invention the film does not comprise polypropylene.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] In order to increase the mechanical properties, the film may be cross-linked with one of the following methods.

[0109] E-beam radiation, gamma radiation, moisture crosslinking using silane grafting compounds, peroxide crosslinking.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] Mechanical Properties

[0117] 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. 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

[0118] A 5-layer film is produced in a commercial hot blown film line with the following recipe

[0119] Outer layer 1, 80% EAO1+15% LDPE+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 75% EAO2+20% LDPE+5% erucamide based slip masterbatch

[0124] See table 1

[0125] The thickness of the structure is 6/1.5/1.5/1.5/5 starting from the outer layerl and going to the outer layer 2.

TABLE-US-00001 TABLE 1 Density Type Description g/cm.sup.3 EA01 Ethylene octene 0.92 copolymer EA02 Ethylene hexane 0.918 copolymer produced with metallocene catalysts ADH1 LLDPE mod. 0.92 Adhesive tie EVOH 1 EVOH with 32% 1.19 ethylene EVOH 2 EVOH with 29% 1.2 ethylene 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

[0126] The weight of the film is 14.7 g/m2.

Example 2

[0127] A 5-layer film is produced in a hot blown film commercial line with the following recipe

[0128] Outer layer 1, 80% EAO1+15% LDPE+5% erucamide based SLIP masterbatch Intermediate layer 100% ADH 1

[0129] Barrier layer EVOH 2

[0130] Intermediate layer 100% ADH1

[0131] Outer layer 2 80% EAO1+15% LDPE+5% erucamide based SLIP masterbatch

[0132] 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.

[0133] The weight of the material is 12.1 g/m2.

TESTS

[0134] 1. Tensile strength and elongation test is done according to ASTM D 882.

[0135] 2. Odour test is done in the following way.

[0136] 3. Coefficient of friction

TENSILE STRENGTH and ELONGATION

[0137] Tensile strength and elongation is measured as per ASTM D882.

[0138] MD stands for machine direction, whereas TD stands for transverse direction.

TABLE-US-00002 TENSILE ELONGA- TENSILE ELONGA- STRENGTH TION STRENGTH TION EXAMPLE (MD) (MD) (TD) (TD) 1 29 340 26 440 2 26 290 22.5 405

ODOUR TESTING

[0139] 10 soiled diapers are put in a film of the present invention and also in a commercially sold film. The commercially sold film is believed to be monolayer.

[0140] The packs are put in PVDC comprising bags, so the odor cannot escape during the time of the evaluation.

[0141] The bags are opened 3 days after the soiling of the diapers and smell was evaluated by a 5-member panel.

[0142] The packs made from EXAMPLE 1 and 2 were found substantially less smelly than the commercially sold ones.

COEFFICIENT OF FRICTION (COF)

[0143] The coefficient of friction is measured as per ASTM D1894 (film-to-film-kinetic coefficient of friction).

[0144] The coefficient of friction was measured for the film according to EXAMPLE 2 compared to a film according to COMPARATIVE EXAMPLE.

[0145] The film according to COMPARATIVE EXAMPLE corresponds to the film of EXAMPLE 2, wherein outer layer 1 and the outer layer 2 comprised an SNR. Hence the film according to Comparative Example comprises an Outer layer 1 and an Outer layer 2 with the following composition:

[0146] 80% EAO1+15% SNR+5% erucamide based SLIP masterbatch

[0147] Where SNR=a calcium carbonate compound

[0148] By comparison of the coefficients of friction of both outer layers we can see that

TABLE-US-00003 COF COF OUTER LAYER 1 TO OUTER LAYER 2 TO OUTER LAYER 1 OUTER LAYER 2 EXAMPLE 2 0.20 0.19 COMPARATIVE 0.32 0.34 EXAMPLE