OVENABLE THERMOFORMING FILM

Abstract

The invention relates to a thermoformable film able to withstand cooking conditions in conventional and microwave ovens. The film comprises a sealing layer comprising ethylene vinyl alcohol (EVOH) copolymer.

Claims

1. A plastic film comprising a sealing layer comprising EVOH.

2. The plastic film according to claim 1, comprising a second layer comprising polyamide.

3. The plastic film according to claim 1, wherein the film comprises a second layer comprising polyester.

4. The plastic film according to claim 1, wherein the ethylene content of the EVOH is between 22 and 50% per mol.

5. The plastic film according to claim 1, wherein the polyolefin content is less than 10% per weight.

6. The plastic film according to claim 1, wherein the EVOH is blended to an elastomer, preferably a styrenic elastomer and/or a flexible polyamide, preferably a polyamide 6/12 and/or an ionomer and/or an EVA and/or a saponified EVA.

7. A method for providing a packaging, the method comprising using a plastic film according to claim 1, as a top lid and/or bottom film for a packaging.

8. Packaging, comprising a plastic film according to claim 1 as a top lid and/or bottom film.

9. A thermoforming process where a plastic film according to claim 1 is used as a top lid and/or bottom film.

10. The plastic film according to claim 2, wherein the ethylene content of the EVOH is between 22 and 50% per mol.

11. The plastic film according to claim 3, wherein the ethylene content of the EVOH is between 22 and 50% per mol.

12. The plastic film according to claim 2, wherein the polyolefin content is less than 10% per weight.

13. The plastic film according to claim 3, wherein the polyolefin content is less than 10% per weight.

14. The plastic film according to claim 4, wherein the polyolefin content is less than 10% per weight.

15. The plastic film according to claim 2, wherein the EVOH is blended to an elastomer, preferably a styrenic elastomer and/or a flexible polyamide, preferably a polyamide 6/12 and/or an ionomer and/or an EVA and/or a saponified EVA.

16. The plastic film according to claim 3, wherein the EVOH is blended to an elastomer, preferably a styrenic elastomer and/or a flexible polyamide, preferably a polyamide 6/12 and/or an ionomer and/or an EVA and/or a saponified EVA.

17. The plastic film according to claim 4, wherein the EVOH is blended to an elastomer, preferably a styrenic elastomer and/or a flexible polyamide, preferably a polyamide 6/12 and/or an ionomer and/or an EVA and/or a saponified EVA.

18. The plastic film according to claim 5, wherein the EVOH is blended to an elastomer, preferably a styrenic elastomer and/or a flexible polyamide, preferably a polyamide 6/12 and/or an ionomer and/or an EVA and/or a saponified EVA.

19. Packaging, comprising a plastic film according to claim 2 as a top lid and/or bottom film.

20. Packaging, comprising a plastic film according to claim 3 as a top lid and/or bottom film.

Description

EXAMPLES

[0086] In a commercial blown film line, the following plastic films were produced.

Example 1

[0087] Outer layer, Ultramid B40LN, thickness 20 microns

[0088] Intermediate layer 1, EVAL E171B, thickness 5 microns

[0089] Intermediate layer 2, Ultramid C40L, 20 microns,

[0090] Intermediate layer 3, UBE 5034FDX40, 10 microns

[0091] Sealing layer, EVAL H171B, 20 microns

[0092] Ultramid B40LN is a polyamide 6 from BASF.

[0093] Ultramid C40L is a copolyamide 6/66 from BASF.

[0094] EVAL E171B is an 44% per mol ethylene EVOH from Kuraray.

[0095] EVAL H171 B is a 38% per mol ethylene EVOH from Kuraray.

[0096] 5034FDX40 is a 6/66 copolyamide from UBE.

[0097] Production of the film was stable with no processing issues.

Example 2

[0098] Outer layer, 90% by weight Ultramid B40LN+10% by weight Grivory G21, thickness 35 microns

[0099] Intermediate layer 1, EVAL E171B, thickness 5 microns

[0100] Intermediate layer 2, Ultramid C40L, 25 microns,

[0101] Intermediate layer 3, UBE 5034FDX40, 10 microns

[0102] Sealing layer, EVAL H171B, 30 microns

[0103] Grivory G21 is an amorphous 6116T copolyamide from EMS.

Example 3

[0104] The Film structure of example 3 was same as example 1 but in the sealing layer the material was changed to a blend of 90% by weight EVAL H171B+10% by weight AM7927

[0105] Where AM 7927 is a nylon modified ionomer from Dupont.

Example 4

[0106] Film structure of example 4 was same as example 1 but in the sealing layer the material was changed to a blend of 90% by weight EVAL H171B+10% by weight GRILON CF6S

[0107] Where Grilon CF6S is a 6/12 polyamide from EMS.

[0108] Examples 3 and 4 had an improved processing compared to example 1.

Evaluation of Examples

[0109] The above examples were tested at a commercial thermoforming machines.

[0110] Examples 1,3,4 are the top lid films while example 2 is the thermoformable bottom web. [0111] 1. Evaluation of thermoformability of film 2. [0112] Thermoformability of film 2 was compared under same conditions (same mold, same heating and forming time, same forming temperature) with the thermoformability of FLEXO-FRESH HB 110, a multilayer PA/PE film used for thermoforming. [0113] It was surprisingly found out that the film of the current invention was able to thermoform in a nice manner similar to the commercial film , having also certain advantages. For example, the puncture properties at the edges of the film (at the corners-areas where the thickness of the film is min after thermoforming) were better compared to the commercial film. [0114] 2. Evaluation of sealing [0115] At sealing temperature 180 C. and sealing time 2 seconds different packs were prepared as of below; [0116] Pack 1=top film as per example 1 and bottom as per example 2 [0117] Pack 2=top film as per example 3 and bottom as per example 2 [0118] Pack 3=top film as per example 4 and bottom as per example 2 [0119] Sealing strength was measured in Instron machine per 15 mm according to ASTM F88. [0120] Seal strength of pack 1 was average 9 N/15 mm while of pack 2 was 14 N/15 mm and of pack 3 was 15 N/15 mm. There were no leakages and unsealed areas. [0121] The level of sealing strength of 9 to 15 N is suitable for the application in the sense that the seal pops during the cook-in in the oven thus allowing the steam from inside the pack to escape without rupturing the pack. [0122] 3. Real oven cook-in test [0123] 250 grams of pork meat was packed in five different packs of each Pack 1, 2 and 3. [0124] Then the packs were placed one after the other in a conventional kitchen oven and the food was cooked by setting the oven temperature at 200 C. and removing the packs after 1 hour. [0125] By examining the film, it was noticed that there was no melting, thermal deterioration or degradation of the film.