CONTAINER LINER FOR HOLDING LIQUIDS

Abstract

The present invention relates to a container liner for holding liquid goods, wherein the liner comprises a film comprising one or more layers, wherein at least one of said layers is a layer L1 comprising (a) ≥20.0 wt %, preferably ≥20.0 and ≤80.0 wt %, with regard to the total weight of that layer L1, of a polyethylene P1 having: •a density of >900 and <915 kg/m.sup.3, preferably of >905 and <913 kg/m.sup.3 as determined in accordance with ASTM D1505 (2010); •a melt mass flow rate of ≥0.1 and ≤5.0 g/10 min, preferably of ≥0.5 and ≤2.0 g/10 min, as determined in accordance with ISO 1133-1 (2011) at 190° C. using a load of 2.16 kg; and (b) ≥20.0 wt %, preferably ≥20.0 and ≤80.0 wt %, with regard to the total weight of that layer L1, of a polyethylene plastomer P2 having: •a density of >880 and <905 kg/m.sup.3, preferably of >890 and <904 kg/m.sup.3 as determined in accordance with ASTM D1505 (2010); •a melt mass flow rate of ≥0.1 and ≤5.0 g/10 min, preferably of ≥0.5 and ≤2.0 g/10 min, as determined in accordance with ISO 1133-1 (2011) at 190° C. using a load of 2.16 kg. Such container liner demonstrates a desirably high flex resistance, combined with a high dart impact resistance, and a high tensile strength.

Claims

1. Container liner for holding liquid goods, wherein the liner comprises a film comprising one or more layers, wherein at least one of said layers is a layer L1 comprising (a) ≥20.0 wt % with regard to the total weight of that layer L1, of a polyethylene P1 having: a density of >900 and <915 kg/m.sup.3, as determined in accordance with ASTM D1505 (2010); a melt mass flow rate of ≥0.1 and ≤5.0 g/10 min, as determined in accordance with ISO 1133-1 (2011) at 190° C. using a load of 2.16 kg; and (b) ≥20.0 wt %, with regard to the total weight of that layer L1, of a polyethylene plastomer P2 having: a density of >880 and <905 kg/m.sup.3, as determined in accordance with ASTM D1505 (2010); a melt mass flow rate of ≥0.1 and ≤5.0 g/10 min, as determined in accordance with ISO 1133-1 (2011) at 190° C. using a load of 2.16 kg.

2. Container liner according to claim 1, wherein the polyethylene plastomer P2 has a fraction of material that is eluted in analytical temperature rising elution fractionation (a-TREF) at a temperature ≤30.0° C. of ≥5.0 wt %, with regard to the total weight of the polyethylene plastomer P2; a shear storage modulus G′ determined at a shear loss modulus G″=5000 Pa of >1000 Pa, G′ and G″ being determined in accordance with ISO 6721-10 (2015) at 190° C.; and/or a chemical composition distribution broadness (CCDB) of ≥15.0, wherein the CCDB is determined according to formula I: $\begin{array}{cc}\mathrm{CCDB}=\frac{T_{z+2}-T_{n-2}}{T_{n-2}}*100& \mathrm{formula}I\end{array}$ wherein T.sub.n−2 is the moment calculated according to the formula II: $\begin{array}{cc}{T}_{n-2}=\frac{.Math.\frac{w\left(i\right)}{{T\left(i\right)}^2}}{.Math.\frac{w\left(i\right)}{{T\left(i\right)}^3}}& \mathrm{formula}\mathrm{II}\end{array}$ and T.sub.z+2 is the moment calculated according to the formula III: $\begin{array}{cc}{T}_{z+2}=\frac{.Math.w\left(i\right).Math.{T\left(i\right)}^4}{.Math.w\left(i\right).Math.{T\left(i\right)}^3}& \mathrm{formula}\mathrm{III}\end{array}$ wherein w(i) is the sampled weight fraction in wt % with regard to the total sample weight in a-TREF analysis of a sample (i) taken at temperature T(i), where T(i)>30° C., the area under the a-TREF curve being normalised to surface area=1 for T(i)>30° C.; and T(i) is the temperature at which sample (i) is taken in a-TREF analysis, in ° C.

3. Container liner according to claim 1, wherein the film comprises at least three layers A/B/C or consists of three layers A/B/C, wherein the layer A is in direct contact with the layer B, and the layer B is in direct contact with the layer C.

4. Container liner according to claim 1, wherein at least the layer B is a layer L1.

5. Container liner according to claim 1, wherein the layer L1 comprises ≥2.5 and ≤15.0 wt % of a low-density polyethylene.

6. Container liner according to claim 1, wherein the film comprises ≥2.5 wt %, of a high-density polyethylene having a density of >945 and <965 kg/m.sup.3, as determined in accordance with ASTM D1505 (2010).

7. Container liner according to claim 1, wherein the film has a thickness of ≥100 μm.

8. Container liner according to claim 1 wherein the film has a density of <912 kg/m.sup.3, as determined in accordance with ASTM D1505 (2010).

9. Container liner according to claim 1, wherein the liner has such dimensions allowing to contain a liquid volume of between 1.0 and 30.0 m.sup.3.

10. Container liner according to claim 1, wherein the liner further comprises at least one closable opening for filling and/or evacuating the liner.

11. Transportation unit comprising a container liner according to claim 1.

12. Transportation unit according to claim 11, wherein the container liner comprises a volume of liquid goods.

13. Transportation unit according to claim 12 wherein the liquid goods are selected from beverages, syrups, oils, fats, vinegars, and detergents.

14. Transportation unit according to claim 11, wherein the transportation unit is a box.

15. (canceled)

16. Container liner of claim 1, wherein at least one of said layers is a layer L1 comprising (a) ≥20.0 and ≤80.0 wt %, with regard to the total weight of that layer L1, of a polyethylene P1 having: a density of >905 and <913 kg/m.sup.3, as determined in accordance with ASTM D1505 (2010); a melt mass flow rate of ≥0.5 and ≤2.0 g/10 min, as determined in accordance with ISO 1133-1 (2011) at 190° C. using a load of 2.16 kg; and (b) ≥20.0 and ≤80.0 wt %, with regard to the total weight of that layer L1, of a polyethylene plastomer P2 having: a density of >890 and <904 kg/m.sup.3, as determined in accordance with ASTM D1505 (2010); a melt mass flow rate of ≥0.5 and ≤2.0 g/10 min, as determined in accordance with ISO 1133-1 (2011) at 190° C. using a load of 2.16 kg.

17. Container liner according to claim 4, wherein the low-density polyethylene has a density of >900 and <935 kg/m.sup.3, and a melt mass flow rate of ≥0.5 and ≤2.0 g/10 min, as determined in accordance with ISO 1133-1 (2011) at 190° C. using a load of 2.16 kg.

Description

[0098] The invention will now be illustrated by the following non-limiting examples.

[0099] A number of multilayer films for use in container liners were produced using the materials as listed in the table below.

Materials

[0100]

TABLE-US-00001 LLDPE1 Dow Elite 5401G, a linear low-density ethylene/1-octene polyethylene copolymer having and MFR2 of 1.0 g/10 min and a density of 918 kg/m.sup.3 LLDPE2 SABIC Supeer 8112L, a linear low-density ethylene/1-octene polyethylene copolymer produced via solution polymerisation using a metallocene catalyst, having an MFR2 of 1.0 g/10 min, and a density of 912 kg/m.sup.3 LLDPE3 Dow Elite AT6101 LLDPE4 Dow Elite 5400G, a linear low-density ethylene/1-octene polyethylene copolymer having and MFR2 of 1.0 g/10 min and a density of 916 kg/m.sup.3 LLDPE5 SABIC Supeer 8112, a linear low-density ethylene/1-octene polyethylene copolymer produced via solution polymerisation using a metallocene catalyst, having an MFR2 of 1.0 g/10 min, and a density of 912 kg/m.sup.3 LDPE SABIC LDPE 2100N0, a low-density polyethylene having an MFR2 of 0.33 g/10 min and a density of 921 kg/m.sup.3 POP1 Dow Affinity PL 1880G, an ethylene/1-octene plastomer produced using a metallocene catalyst, having an MFR2 of 1.0 g/10 min, and a density of 902 kg/m.sup.3 POP2 SABIC Cohere 8185, a polyethylene plastomer produced via solution polymerisation using a metallocene catalyst, having an MFR2 of 1.0 g/10 min, and a density of 885 kg/m.sup.3 POP3 SABIC Cohere S100, a polyethylene plastomer produced via solution polymerisation using a metallocene catalyst, having an MFR2 of 1.0 g/10 min, and a density of 900 kg/m.sup.3 HDPE SABIC HDPE FI1157, a high-density polyethylene having a density of 957 kg/m.sup.3, an MFR2 of 11 g/10 min, and an MFR5 of 0.35 g/10 min.
Further selected properties of the above materials are listed in the table below.

TABLE-US-00002 LLDPE5 POP1 POP3 a-TREF <30 0.9 3.9 10.8 a-TREF 30-94 99.1 96.0 89.2 a-TREF >94 0 0.1 0 CCDB 8.6 19.1 20.8 G′ at G″ = 1883 1372 5000 Pa (Pa) [0101] a-TREF<30 indicates the fraction of the polymer that is eluted in a-TREF according to the method presented above in the temperature range ≤30.0° C., expressed in wt %, and represents the amorphous fraction of the polymer, calculated by subtracting the a-TREF 30-94 and the a-TREF>94 fraction from 100.0 wt %; [0102] a-TREF 30-94 indicates the fraction of the polymer that is eluted in a-TREF in the temperature range of >30.0 and ≤94.0° C., expressed in wt %, and represents the branched fraction of the polymer; [0103] a-TREF>94 indicates the fraction of the polymer that is eluted in a-TREF in the temperature range of >94.0 and <140° C., expressed in wt %, and represents the linear fraction of the polymer; and [0104] the CCDB is the chemical composition distribution broadness calculated according to the method described herein above.

[0105] Using the above materials, a number of three-layer films were produced via multi-layer blown film extrusion, wherein a first outer layer was provided for by a first extruder, a core layer was provided for by a second extruder, and a second outer layer was provided for by a third extruder. Each of the extruders supplied material to a circular die having a diameter of 60 mm and a die gap of 2.0 mm. Each extruder was a single-screw extruder having a screw diameter of 25 mm. The blow-up ratio was 2.5. The total output of the combined extruders was 8 kg/h, wherein the first extruder provided 30% thereof to form the first outer layer, the second extruder provided 40% to form the core layer, and the third extruder provided 30% to form the second outer layer.

[0106] The extruders were equipped with four barrel zones, and a die in which the layers were combined to form the multi-layer film. The temperature in the extruder zones was in each of the extruders as follows:

TABLE-US-00003 Zone 1 (feed zone) 170° C. Zone 2 185° C. Zone 3 190° C. Zone 4 190° C. Die 190° C.

[0107] According to the process as set out here above, films were produced having a thickness of 125 μm, according to the material formulations for each of the layers, and thus the feed compositions for each of the corresponding extruders, as presented here below.

TABLE-US-00004 Example First outer layer Core layer Second outer layer 1 90% LLDPE1 60% POP1 90% LLDPE1 10% LDPE 30% LLDPE4 10% LDPE 10% LDPE 2 90% LLDPE1 90% LLDPE3 90% LLDPE1 10% LDPE 10% LDPE 10% LDPE 3 90% LLDPE2 30% POP2 90% LLDPE2 10% LDPE 60% LLDPE5 10% LDPE 10% LDPE 4 90% LLDPE2 60% POP3 90% LLDPE2 10% LDPE 30% LLDPE5 10% LDPE 10% LDPE 5 90% LLDPE2 30% POP2 90% LLDPE2 10% LDPE 60% LLDPE5 10% LDPE 10% HDPE

[0108] In the above table, all percentages are to be understood as weight percentage of the particular material as part of the total weight of the material of that particular layer of each film.

[0109] The films as produced via the above procedure were subjected to testing of properties as presented in the table below.

TABLE-US-00005 Example 1 2 3 4 5 Film density 914 914 911 911 911 Dart impact 2312 2480 2252 2552 2420 Tensile strength 42 48 53 56 50 MD Tensile strength TD 47 47 53 54 45 Modulus MD 139 153 128 136 128 Modulus TD 170 141 131 130 124 Puncture force 71.3 71.0 88.0 89.6 93.2 Puncture break 2.8 2.7 4.9 4.7 5.2 Pinhole count 4 5.5 3 2 0.5

[0110] Wherein: [0111] the film density is determined in accordance with ASTM D1505 (2010) and expressed in kg/m.sup.3; [0112] the Dart impact strength is determined as the impact failure weight in accordance with ASTM D1709 (2016), method A, and expressed in g; [0113] the tensile properties tensile strength and modulus (1% secant modulus) were determined in accordance with ASTM D882 (2012), in the machine direction (MD) and transverse direction (TD) of the film sample; [0114] puncture force is the maximum force as determined in accordance with ASTM D5748-95 (2012), expressed in N; [0115] puncture break is the puncture energy to break as determined in accordance with ASTM D5748-95 (2012), expressed in J; and [0116] pinhole count is the number of pinholes occurring on a sample per 300 cm.sup.2 after 10800 cycles when tested in accordance with ASTM F392-93 (2004).

[0117] From the above results, it can be observed that the film samples of the container liners as per the present invention, represented by examples 3-5, demonstrate a reduction in pinhole count, increased maximum puncture force, and increased puncture energy to break. This renders such container liners particularly suitable for holding liquid goods, as the chances of leakage of liquids occurring are significantly reduced.