MULTI-LAYER FILM

Abstract

The present invention concerns a multi-layer film for cling film applications comprising at least three layers, with two outer layers, at least one core layer, preferably exactly one core layer, wherein at least one or both outer layer(s) comprise(s) between 73 wt. % and 99.5 wt. % or between 73 wt. % and <99.5 wt. % of LLDPE based on the total weight of the respective layer and between 0.5 wt. % and 7 wt. % of HDPE based on the total weight of the respective layer.

Claims

1. A multi-layer film for cling film applications comprising at least three layers, with two outer layers, at least one core layer, wherein at least one outer layer comprises between 73 wt. % and 99.5 wt. % of linear low density polyethylene based on the total weight of the respective layer and between 0.5 wt. % and 7 wt. % of high density polyethylene based on the total weight of the respective layer.

2. The multi-layer film according to claim 1, wherein the layer film comprise exactly three layers.

3. The multi-layer film according to claim 1, wherein the outer layers are identical and/or comprise the same linear low density polyethylene.

4. The multi-layer film according to claim 1, further comprising an amount of additive in at least one or in both outer layer(s) and or in the core layer of between >0 and <20 wt. % based on the total weight of the layer.

5. The multi-layer film according to claim 1, wherein the amount of linear low density polyethylene in at least one or in both of the outer layer(s) is between 73 and 99.5 wt. %.

6. The multi-layer film according to claim 1, wherein the amount of high density polyethylene in at least one or in both of the outer layer(s) is between 0.6 and 6.5 wt. % based on the total weight of the respective layer.

7. The multi-layer film according to claim 1, wherein the melt flow index of the linear low density polyethylene in at least one or in both of the outer layers ranges from 0.1 to 5 g/10 min.

8. The multi-layer film according to claim 1, wherein the linear low density polyethylene in at least one or in both of the outer layers and/or in the core layer is a copolymer of ethylene and 1-octene.

9. The multi-layer film according to claim 1, wherein the linear low density polyethylene in at least one or both of the outer layer(s) or in the core layer has a density between 0.850 g/cm.sup.3 and 0.945 g/cm.sup.3.

10. The multi-layer film according to claim 1, wherein a core layer of a multi-layer film comprises at least one polyolefin and/or blends of two or more of LLDPE, LDPE or HDPE.

11. The multi-layer film according to claim 1, wherein the melt flow index as determined using ISO1133:2011 (190 C./2.16 kg) of the HDPE ranges from 0.1 to 4 g/10 min.

12. The multi-layer film according to claim 1, wherein the core layer comprises between 10 and 30 wt. % based on the total weight of the respective layer of LDPE.

13. The multi-layer film according to claim 1, wherein the core layer comprises between >50 and 89.5 wt. % based on the total weight of the respective layer of LLDPE.

14. Article and/or packaging comprising the multi-layer film according to claim 1.

15. (canceled)

16. The multi-layer film according to claim 1, wherein the at least one or in both outer layer(s) and or in the core layer further comprises anti-fog agent in an amount of between 0.5 and <20 wt. % based on the total weight of the layer.

17. The multi-layer film according to claim 1, wherein the amount of linear low density polyethylene in at least one or in both of the outer layer(s) is between 73.5 and 98.9 wt. % based on the total weight of the respective layer; and wherein the amount of high density polyethylene in at least one or in both of the outer layer(s) is between 0.7 and 5 wt. % based on the total weight of the respective layer.

18. The multi-layer film according to claim 1, wherein the linear low density polyethylene in at least one or both of the outer layer(s) or in the core layer has a density between 0.905 to 0.920 g/cm.sup.3.

19. The multi-layer film according to claim 1, wherein a core layer of a multi-layer film comprises a blend of LLDPE and LDPE.

20. A multi-layer film for cling film applications comprising: at least three layers, with two outer layers, at least one core layer, wherein at least one outer layer comprises between 73 and 99 wt. % of linear low density polyethylene based on the total weight of the respective layer and between 0.8 and 3.5 wt. % of high density polyethylene based on the total weight of the respective layer; wherein at least one or in both outer layer(s) and or in the core layer comprises 0.5 and 15 wt. % anti-fog agent, based on the total weight of the layer; wherein a melt flow index of the linear low density polyethylene in at least one or in both of the outer layer(s) ranges from 0.1 to 5 g/10 min; wherein the linear low density polyethylene in at least one or in both of the outer layers and/or in the core layer is a copolymer of ethylene and 1-octene; wherein the linear low density polyethylene in at least one or both of the outer layer(s) or in the core layer has a density between 0.900 to 0.934 g/cm.sup.3; wherein a core layer comprises a blends of >50 and 89.5 wt. % LLDPE and between 10 and 30 wt. % LDPE, based on the total weight of the core layer; and wherein the melt flow index as determined using ISO1133:2011 (190 C./2.16 kg) of the HDPE ranges from 0.1 to 4 g/10 min.

Description

EXAMPLES

[0057] The film samples were processed on a Polyrema multi-layer blown film line. The line is equipped with three 50 mm extruder with 25 L/D barrier screws. The line was equipped with a 200 mm die and a die gap of 2.5 mm. The line was equipped with dual lip cooling ring and IBC. In order to keep the influence of further parameters as low as possible, the overall throughput of approximately 50 kg/h and blow up ratio (BUR) of 2.5 were kept constant. Barrel temperature profiles were ramped from 40 C. at the feed section to 220 C. at the die.

[0058] The overall film thickness was 14 m, the individual layer thickness 3/8/3 m.

[0059] Two three layer film samples (A and B) with the following compositions (see Table 1) were prepared.

TABLE-US-00001 TABLE 1 Thickness (m) First outer 3 A: 82.5 wt. %, A: 5 wt. % and layer 1 B: 85.5 wt. % and B: 2 wt. % and C: 87.5 wt. % C: 0 wt. % SABIC 8108 (LLDPE) SABIC HDPE F04660 Core layer 2 8 70 wt. % 20 wt. % SABIC 8118 (LLDPE) SABIC 2102TX00 Second outer 3 A: 82.5 wt. %, A: 5 wt. % and layer 3 B: 85.5 wt. % and B: 2 wt. % and C: 87.5 wt. % C: 0 wt. % SABIC 8108 (LLDPE) SABIC HDPE F04660

[0060] Composition C is reported as comparative example. The remaining to 100 wt. % for each layer in the compositions reported in Table 1 is made up by an anti-fog agent, namely Atmer 7340 by Croda, which is a glycerol ester in an amount of 20 wt. % in polyethylene.

[0061] For all samples (A, B and C), coefficients of friction between the inside and the outside layer were measured according to ASTM D1894-11 for five specimen. Results are reported in Table 2 below are averages of the five measurements.

TABLE-US-00002 TABLE 2 Sample A B C Coefficient of friction ASTM D1894-11 Inside - outside Static friction coefficient x 0.43 0.65 0.85 Static friction coefficient st. dev 0.06 0.11 0.07 Dynamic friction coefficient x 0.79 0.97 1.07 Dynamic friction coefficient st. dev 0.07 0.05 0.03 Number of specimens 5 5 5

[0062] One can see from the results above that both static and dynamic friction coefficients are reduced for samples A and B compared to comparative sample C. A further improvement can be seen for sample A over sample B. This may contribute to improve machinability.