Polyolefin film laminate for package having advantageous hermiticity

Abstract

The invention relates to a film laminate comprising: A. a first biaxially-oriented polypropylene (BOPP) film; B. a second biaxially-oriented polypropylene (BOPP) film; C. a polyethylene film comprising therein in this order: i. a first polyethylene layer; ii. a second polyethylene layer; and iii. a third polyethylene layer; wherein the films A, B and C are positioned in this order; wherein the first polyethylene layer (i) comprises a low-density polyethylene (LDPE) having a density of > 900 and < 930 kg / m3 and a linear low-density polyethylene (LLDPE) having a density of ≥ 912 and ≤ 940 kg / m3; wherein the second polyethylene layer (ii) comprises the LDPE and the LLDPE; wherein the third polyethylene layer (iii) comprises an ethylene-based copolymer having a density of ≥ 850 and ≤ 910 kg / m3, preferably the third polyethylene layer (iii) comprises ≥ 50.0 wt%, more preferably ≥ 70.0 wt%, of the ethylene-based polymer; wherein density is as determined in accordance with ASTM D792 (2013).

Description

24POLY0076-WO-ORD 1Polyolefin film laminate for package having advantageous hermiticity.

[0001] The present invention relates to a polyolefin film laminate for packaging, wherein the laminate has advantageous hermiticity properties.

[0002] Polymer compositions, such as polyolefin-comprising polymer compositions, are used very ubiquitously in a vast array of materials solutions, such as packaging solutions. Polymer compositions can be formed into a wide range of shapes to enable the creation of a purpose oriented packaging application.

[0003] A particularly advantageous family of polymers is polyolefins. Polyolefins are the world’s most abundantly available polymer material; they are readily thermoplastically processable, have a high degree of inertness, have a good mechanical property profile, and have very low permeability, to name only some highly appreciated properties of polyolefins that make them the number one polymer in the world.

[0004] Notably, polyolefins are very suitable to use for packaging of perishable products, or products that are susceptible to contamination. For example, a large volume of polyolefins finds its application in food packaging solutions. Choosing the right polyolefin formulation may allow for production of a package that keeps the food fresh, provides an appropriately robust package, and allows for a package offering that is appealing to customers, and typically in a rather cost-economic way.

[0005] The family of polyethylenes contains a wide array of members. The main categories are high-density polyethylenes (HDPE), linear low-density polyethylenes (LLDPE), low density polyethylenes (LDPE) and polyethylene elastomers / plastomers (POE / POP). Each of HDPE, LLDPE, and POP / POE are produced by catalysed polymerisation processes, typically using heterogenous catalysts such as Ziegler-type catalysts, Chromium-type catalysts, or homogeneous catalysts such as metallocene-type catalysts. Such catalytic polymerisation may be performed at relatively modest pressures and temperatures.

[0006] LDPE is produced via a different polymerisation process, being free-radical polymerisation. In such process, LDPE is produced from ethylene at high pressure, such as above 1500 MPa, at temperatures of for example 250-300°C. The free-radical polymerisation is24POLYOQ76-WO-ORD 2 typically initiated by peroxides or other chemical compounds the form radicals under the conditions of LDPE polymerisation. LDPE production may for example be performed in tubular reactors or in autoclave reactors.

[0007] Polyethylenes of the HDPE type may for example have a density of > 940 kg / m2, such as > 940 and < 970 kg / m2, preferably of > 945 and < 970 kg / m3, more preferably of > 950 and < 965 kg / m3. HDPE type polyethylenes may be homopolymers or copolymers, such as copolymers of ethylene and one or more comonomers, preferably one comonomer, selected from C4-C8 a-olefins, for example wherein the comonomer(s) is selected from 1 -butene, 1- hexene and 1-octene. For example, the HDPE may comprise < 10.0 wt% of moieties derived from the comonomer, preferably < 5.0 wt%, more preferably > 0.1 and < 4.0 wt%, with regard to the total weight of the HDPE.

[0008] Polyethylenes of the LLDPE type may for example have a density of > 910 and < 940 kg / m3, preferably > 915 and < 935 kg / m3, more preferably of > 915 and < 930 kg / m3. LLDPE type polyethylenes preferably are copolymers, preferably copolymers of ethylene and a further C4-C8 a-olefin, for example wherein the further C4-C8 a-olefin is selected from 1 -butene, 1- hexene and 1-octene. For example, the LLDPE may comprise > 5.0 wt% and < 40.0 wt% of moieties derived from the comonomer, preferably > 5.0 wt% and < 30.0 wt%, more preferably > 10.0 and < 30.0 wt%, with regard to the total weight of the LLDPE.

[0009] In packaging solutions, a parameter that in many cases is paramount to the suitability of the solution is the hermiticity of a package. In this context, hermiticity means the extent to which the contents of a package are shielded from the environment outside the package. Particularly, when the package is to contain perishable products, or products that are susceptible to contamination, this is a critical parameter.

[0010] A widely applied type of packaging are sealed bag-type packages. Such packages can be produced by providing a film or sheet material that is to be formed into the package, which may be continuously supplied to a hollow forming tube, such as be supplying a roll of the flexible film or laminate. The film may then be wrapped into a tube, for example by wrapping around a forming tube, pulled towards the end of the forming tube, while a seal is made to connect the two long sides of the film together to form a tubular shaped film object. As this seal is made in the direction parallel with the processing direction of the film through the packaging machine, this seal may be referred to as the machine-direction seal.24POLYOQ76-WO-ORD 3

[0011] The so-formed continuous tube can be formed into package compartments.

[0012] When using a thermoplastic polymer material for the film, a widely used technique for producing the seals is by thermal sealing. This involves subjecting an area of the film where the seal is to be formed to a heat source to bring the part of the film that is to seal to a temperature at which it is sufficiently softened or molten to adhere to a second surface, and contacting that softened area to a surface area to which it is to be sealed to. Commonly, the area to which the softened area is to be sealed to is of the same material, being another area of the same film, and typically this surface is also subjected to a heat source to bring it to a temperature at which it can adhere to the other surface. By so, a thermal seal is formed by contacting two heated and thereby adhesive surfaces with one another.

[0013] In forming a tubular shape from a continuous film or laminate, as presented above, the sealable surface of the film or laminate typically is positioned to be the inner surface of the tubular shape.

[0014] When the machine-direction seal is accordingly formed by contacting the inner surface of two sides of the film or laminate, a fin seal is formed that can be folded to form a fold-over seam.

[0015] The thus formed, continuous, tubular packaging material can be converted into individual compartments each comprising the desired contents by forming a first perpendicular thermal seal into the tubular shape, introducing the contents to be packed into the package, and forming a second perpendicular thermal seal into the tubular shape at a defined distance upwards from the first perpendicular seal. By so, the tubular shape is formed into a package compartment containing the desired contents to be packed, and the package compartment is completely sealed by ensuring that the machine-direction seal and the two perpendicular seals appropriately connect to each other. Such packaging technique is known in the art as the form- fill-seal technique.

[0016] A specific application of such packaging technique is the so-called vertical form-fill-seal process, also referred to as VFFS. The VFFS process allows for packaging of for example powdery, liquid, or paste-like goods, amongst which many sorts of foodstuff products. As explained, in VFFS the package is formed from a film or laminate by sealing into a tubular form, applying a perpendicular seal, filling the package with the goods to be contained, and thereafter24POLYOQ76-WO-ORD 4 closing the package compartment by forming a second perpendicular seal. In such operation, a critical parameter is achieving appropriate closure properties, also referred to as hermiticity, of the second perpendicular seal. Since the package content has been introduced into the package, the inner surface of the laminate may have contacted a fraction of the content material prior to the creation of the second seal. This may lead to problems in forming the seal, such as due to contamination of the inner laminate surface in the area where the seal is to be formed. Inappropriate hermiticity of the package may lead to deterioration of the contents or leaks. Clearly, it is desired to minimize the occurrence thereof.

[0017] Packaging techniques as described above are suitable for continuous production of packages. By so, the contents can be packed in very fast and economic operations. Such fast and continuous operations require that the seals can be continuously produced at very high speed, without compromising the package quality.

[0018] The present inventors have now provided therefor a film laminate comprising:A. a first biaxially-oriented polypropylene (BOPP) film;B. a second biaxially-oriented polypropylene (BOPP) film;C. a polyethylene film comprising therein in this order: i. a first polyethylene layer; ii. a second polyethylene layer; and iii. a third polyethylene layer; wherein the films A, B and C are positioned in this order; wherein the first polyethylene layer (i) comprises a low-density polyethylene (LDPE) having a density of > 900 and < 930 kg / m3and a linear low-density polyethylene (LLDPE) having a density of > 912 and < 940 kg / m3; wherein the second polyethylene layer (ii) comprises the LDPE and the LLDPE; wherein the third polyethylene layer (iii) comprises an ethylene-based copolymer having a density of > 850 and < 910 kg / m3, preferably the third polyethylene layer (iii) comprises > 50.0 wt%, more preferably > 70.0 wt%, even more preferably > 75.0 wt%, of the ethylenebased polymer; wherein density is as determined in accordance with ASTM D792 (2013).24POLYOQ76-WO-ORD 5

[0019] Such laminate allows for the production of a package, such as a VFFS package, at high hermiticity and high seal strength, wherein production of the package may occur over a broad sealing temperature window.

[0020] The low-density polyethylene may for example have a density of > 905 and < 928 kg / m3, preferably of > 910 and < 925 kg / m3, more preferably of > 915 and < 925 kg / m3.

[0021] The low-density polyethylene may for example have an MFR2 of > 0.2 and < 10.0 g / 10 min, preferably > 0.2 and < 5.0 g / 10 min, more preferably > 0.5 and < 5.0 g / 10 min, even more preferably > 0.5 and < 2.5 g / 10 min, wherein the MFR2 is the melt mass-flow rate determined at 190°C under a load of 2.16 kg in accordance with ASTM D1238-13.

[0022] The LLDPE may for example be a copolymer of ethylene and 1 -butene or 1 -hexene, preferably a copolymer of ethylene and 1-butene. For example, the LLDPE may comprise > 2.0 and < 25.0 wt% of moieties derived from 1-butene or 1-hexene, preferably > 5.0 and < 15.0 wt%. The LLDPE may for example have a density of > 912 and < 930 kg / m3, preferably > 912 and < 925 kg / m3, more preferably > 915 and < 920 kg / m3. The LLDPE may for example have an MFR2 of > 0.5 and < 10.0 g / 10 min, preferably > 0.5 and < 5.0 g / 10 min, more preferably > 1.0 and < 5.0 g.10 min, even more preferably of > 1.5 and < 3.0 g.10 min. The LLDPE may for example be a polymer produced using a Ziegler-Natta type catalyst or using a metallocene-type catalyst.

[0023] The ethylene-based copolymer may for example have a density of > 870 and < 910 kg / m3, more preferably > 890 and < 910 kg / m3, as determined in accordance with ASTM D792 (2013). The ethylene-based copolymer may for example have a melt mass-flow rate determined at 190°C under a load of 2.16 kg (MFR2) in accordance with ASTM D1238-13 of > 0.2 and < 10.0 g / 10 min, preferably of > 0.2 and < 5.0 g / 10 min, more preferably > 0.5 and < 5.0 g / 10 min, even more preferably > 0.5 and < 2.5 g / 10 min.

[0024] The ethylene-based copolymer may for example be a copolymer comprising polymer units derived from ethylene and polymer units derived from 1 -octene. For example, the ethylene-based copolymer may be an ethylene / 1 -octene copolymer comprising < 18.0 wt% of polymeric units derived from 1 -octene, with regard to the total weight of the ethylene-based copolymer, preferably > 10.0 and < 18.0 wt%, more preferably >15.0 and < 18.0 wt%.24POLY0076-WO-ORD 6

[0025] The ethylene-based copolymer may for example have a molecular weight distribution Mw / Mn of > 3.0, preferably of > 3.0 and < 4.0, more preferably of > 3.0 and < 3.5, wherein Mwis the weight average molecular weight and Mnis the number average molecular weight, as determined in accordance with ASTM D6474 (2012).

[0026] The ethylene-based copolymer may for example have a fraction eluted in a-TREF below 30°C of < 10.0 wt%, preferably > 5.0 and < 10.0 wt%, as determined in accordance with the method of the description..

[0027] The ethylene-based copolymer may for example have a chemical composition distribution broadness (CCDB) of < 25.0, preferably > 15.0 and < 25.0, as determined in accordance with the method of the description.

[0028] The ethylene-based copolymer may for example have a weight average molecular weight (Mw) of > 100 kg / mol, preferably > 102 and < 150 kg / mol.

[0029] The comonomer content and the comonomer type may be determined by13C NMR, such as on a Bruker Avance 500 spectrometer equipped with a cryogenically cooled probe head operating at 125°C, whereby the samples are dissolved at 130°C in C2D2CI4 containing DBPC as stabiliser.

[0030] In the context of the present invention, the CCDB is determined according to formula I: 100formula I wherein• Tn-2 is the moment calculated according to the formula II:formula II andTZ+2 is the moment calculated according to the formula III:24POLY0076-WO-ORD 7formula III 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.

[0031] According to the invention, analytical temperature rising elution fractionation, also referred to as a-TREF, may be carried out using a Polymer Char Crystaf-TREF 300 equipped with stainless steel columns having a length of 15 cm and an internal diameter of 7.8 mm, with a solution containing 4 mg / ml of sample prepared in 1,2-dichlorobenzene stabilised with 1 g / l Topanol CA (1 ,1 ,3-tri(3-tert-butyl-4-hydroxy-6-methylphenyl)butane) and 1 g / l Irgafos 168 (tri(2,4-di-tert-butylphenyl) phosphite) at a temperature of 150°C for 1 hour. The solution may be further stabilised for 45 minutes at 95°C under continuous stirring at 200 rpm before analyses. For analyses, the solution was crystallised from 95°C to 30°C using a cooling rate of 0.1°C / min. Elution may be performed with a heating rate of 1°C / min from 30°C to 140°C. The set-up may be cleaned at 150°C. The sample injection volume may be 300 pl, and the pump flow rate during elution 0.5 ml / min. The volume between the column and the detector may be 313 pl. The fraction that is eluted at a temperature of <30.0°C may in the context of the present invention be calculated by subtracting the sum of the fraction eluted >30.0°C from 100%, thus the total of the fraction eluted < 30.0°C, and the fraction eluted >30.0°C to add up to 100.0 wt%.

[0032] Particularly, a-TREF may be carried out using a Polymer Char Crystaf-TREF 300 using a solution containing 4 mg / ml of the polymer in 1,2-dichlorobenzene, wherein the solution is stabilised with 1 g / l 1,1,3-tri(3-tert-butyl-4-hydroxy-6-methylphenyl)butane and 1 g / l tri(2,4-di- tert-butylphenyl) phosphite) at a temperature of 150°C for 1 hour, and further stabilised for 45 minutes at 95°C under continuous stirring at 200 rpm, wherein the prior to analyses the solution is crystallised from 95°C to 30°C using a cooling rate of 0.1°C / min, and elution is performed at a heating rate of 1°C / min from 30°C to 140°C, and wherein the equipment has been cleaned at 150°C.24POLYOQ76-WO-ORD 8

[0033] The layer i. of the film C may for example comprise < 50 wt% of the LDPE and > 50 wt% of the LLDPE, with regard to the total weight of the layer i. For example, the layer i. may comprise > 10.0 and < 30.0 wt% of the LDPE. For example, the layer i. may comprise > 70.0 and < 90.0 wt% of the LLDPE. For example, the layer i. may consist of the LDPE and the LLDPE. For example, the layer i. may comprise > 10.0 and < 30.0 wt% of the LDPE and > 70.0 and < 90.0 wt% of the LLDPE. For example, the layer i. may consist of > 10.0 and < 30.0 wt% of the LDPE and > 70.0 and < 90.0 wt% of the LLDPE.

[0034] The layer ii. of the film C may for example comprise < 50 wt% of the LDPE and > 50 wt% of the LLDPE, with regard to the total weight of the layer ii. For example, the layer ii. may comprise > 10.0 and < 30.0 wt% of the LDPE. For example, the layer ii. may comprise > 70.0 and < 90.0 wt% of the LLDPE. For example, the layer ii. may consist of the LDPE and the LLDPE. For example, the layer ii. may comprise > 10.0 and < 30.0 wt% of the LDPE and > 70.0 and < 90.0 wt% of the LLDPE. For example, the layer ii. may consist of > 10.0 and < 30.0 wt% of the LDPE and > 70.0 and < 90.0 wt% of the LLDPE.

[0035] For example, the layer i. and the layer ii. may have the same composition.

[0036] The layer iii. of the film C may for example comprise > 60.0 and < 90.0 wt% of the ethylene-based copolymer, preferably > 60.0 and < 90.0 wt%, more preferably > 60.0 and < 80.0 wt%, or > 75.0 and < 90.0 wt%, with regard to the total weight of the layer iii. The layer iii. may for example comprise > 5.0 and < 20.0 wt% of the LLDPE, preferably > 10.0 and < 15.0 wt%. The layer iii. may for example comprise > 5.0 and < 20.0 wt% of the LDPE, preferably > 10.0 and < 15.0 wt%. For example, the layer iii. may comprise > 60.0 and < 80.0 wt% of the ethylene-based copolymer, > 10.0 and < 15.0 wt% of the LLDPE, and > 10.0 and < 15.0 wt% of the LDPE. For example, the layer iii. may comprise > 60.0 and < 75.0 wt% of the ethylenebased copolymer, > 10.0 and < 15.0 wt% of the LLDPE, and > 10.0 and < 15.0 wt% of the LDPE.

[0037] The layer iii. may comprise a slip agent, preferably an erucamide, and / or an antiblock agent, preferably a natural silicate.24POLYOQ76-WO-ORD 9

[0038] The film C may comprise > 10.0 and < 40.0 wt% of the layer iii., with regard to the total weight of the film C. Preferably, the film C comprises > 10.0 and < 30.0 wt% of the layer iii. The film C may comprise > 60.0 and < 90.0 of the combined weight of layers i. and ii. The film C may have a thickness of > 20 and < 100 pm. For example, the film C may have a thickness of > 20 pm and < 50 pm, preferably of > 20 pm and < 40 pm, or > 60 pm and < 100 pm. The film C may be a cast film of a blown film.

[0039] In the polyethylene film C, the layer (i) is a first outer layer of the polyethylene film, and the layer (iii) is a second outer layer of the polyethylene film.

[0040] It is preferred that the first BOPP film has a thickness of > 10 and < 50 pm, preferably of > 20 and < 50 pm.

[0041] In an embodiment, the second BOPP film is a barrier film having an oxygen transmission rate (OTR) of < 1.0 cm3 / m2day, as determined in accordance with ASTM D3985-05 at 23°C, 0% RH, and a water vapour transmission rate (WVTR) of < 1.0 g / m2day as determined in accordance with ASTM F1249-13 at 23°C, 0% RH.

[0042] The invention also relates to a process for production of a film laminate, wherein the process involves: providing the first BOPP film and the second BOPP film; laminating the first and the second BOPP film to form a first laminate, preferably wherein the laminating occurs solvent-free; providing the polyethylene film; subjecting the polyethylene film to a corona treatment on the surface of the first polyethylene layer, preferably such that a surface tension of > 0.038 N / m is obtained, as determined in accordance with ASTM D5946-09; and laminating the first laminate and the polyethylene film to form the film laminate, preferably wherein the laminating occurs solvent-free.

[0043] The invention also relates to an article comprising the film laminate, preferably wherein the article is a pouch. Furthermore, the invention relates to a process for production of an article, wherein the process involves subjecting the film to a vertical form-fill-seal process (VFFS).24POLY0076-WO-ORD 10

[0044] Also, the invention relates to the use of the film to improve the hermeticity as tested in accordance with ASTM D3078-94 of a form-fill-seal package.

[0045] The invention will now be illustrated by the following non-limiting examples.

[0046] In the examples of the present invention, the following materials were used:

[0047] Properties of the polyethylene-type materials used in the examples are presented in the table below:wherein:24POLY0076-WO-ORD 11• The MFR2 is the melt mass-flow rate, determined at 190°C under a load of 2.16 kg, in accordance with ASTM D1238 (2013);• The density is determined in accordance with ASTM D792 (2013);• The fraction a-TREF <30°C is the fraction eluted in an a-TREF analysis conducted as described above below 30°C;• The weight-average molecular weight (Mw) and the number-average molecular weight (Mn) were determined in accordance with ASTM D6474 (2012);• The comonomer content indicates the weight quantity of units present in the polymer that are derived from the comonomer, also referred to as the quantity of moieties derived from the comonomer, with regard to the total weight of the polymer, expressed in wt%;• The comonomer type indicates the type of comonomer used in the production of the polymer, where C8 is 1 -octene, C6 is 1 -hexene and C4 is 1 -butene;• The peak melting temperature (Tp m) is determined using differential scanning calorimetry according to ASTM D3418 (2008), expressed in °C;• The CCDB is the chemical composition distribution broadness calculated according to the method described herein above.

[0048] For demonstrating the present invention, a number of laminates were produced having the structure A / / B / / C, wherein A is a BOPP1 film; B is a BOPP2 film; and C is a coextruded 3- layer film produced by blow film extrusion according to the conditions set out below:Four different formulations for the film C were prepared according to the table below:24POLYOQ76-WO-ORD 12

[0049] Wherein the weight of layer indicates the weight of each layer C1 through C3 with regard to the total weight of the film C, and the weight indication in the formulation indicates the weight of each ingredient in a given layer with regard to the total weight of that layer.

[0050] In the coextruded film, the layer C1 was subjected to corona treatment to obtain a surface tension > 0.038 N / m, as determined in accordance with ASTM D5946-09. The layer C3 was the sealing layer.

[0051] The first laminate was formed by first laminating the BOPP1 film, as film A of the laminate, to the BOPP2 film, as film B of the laminate, using a SINSTAR solvent-free laminator at line speed of 200 m / min. Subsequently, the first laminate was laminated to each of the films C as in the table above wherein the side B of the first laminate was contacted with layer C1 of the film C, to form the second laminates 1-4 of structure A / B / C, wherein the side C forms the side that is to be sealed in forming the package.24POLYOQ76-WO-ORD 13

[0052] The laminates were converted into pouches for hermiticity testing. Such pouches were prepared using the laminates of each of the examples 1-4 above. The pouches were prepared using an EPlus model RAD-G6 VFFS machine, an industrial multiple lane stick pouch machine. The line speed was 360 packs / min. The vertical seal was sealed at 155°C to ensure that no leakage could occur along the vertical seal. By horizontal sealing at 155 or 160°C, pouches were made having a size of 45 mm width and 180 mm length. The seal in the horizontal direction was made at a pressure of 0.35 MPa, using a sealing time of 0.40, 0.45 or 0.55 s. The packages were filled with 20 mg of powder through the online filling system.

[0053] For each of the examples, packs that were produced according to the conditions as set out above were subjected to hermiticity testing. Hermeticity testing was performed according to ASTM D3078-94 on PARAM, MFY-01. The sample pouches were submerged in water in a sealed tank, at room temperature, and the pressure in the tank was reduced to 60 kPa. The pouch was monitored for 30 second to identify air bubbles escaping from the pouch.

[0054] In the table below, the hermetic ratio for each of the package samples that were prepared using the laminates 1-4 is presented.

[0055] In addition to the hermiticity, the seal strength and the hot tack strength were also tested.The seal strength was determined in accordance with ASTM F88, using method A, on24POLYOQ76-WO-ORD 14 specimens of 15 mm width. Fin-seals were prepared according to ASTM F2029 at different temperatures. Two samples of the same film were compressed together, with layer C of the first film sample contacting layer C of the second film sample. Seals were produced by applying a force of 3.0 bar for 0.5 sec. The press used for preparing the seal was heated to various temperatures to identify the strength of the seal when produced at different temperatures.

[0056] The seal strength was tested using a tensile testing machine with a testing speed of 200 mm / min, and a grip distance of 10 mm. The maximum load was recorded as the seal strength.

[0057] The values in the table above are the seal strengths of the horizontal seals produced at the sealing temperature as indicated in the table, expressed in N / 15mm. The data in the table above are also reflected in Figure 1.

[0058] Further, the hot tack strength of the laminates was determined. Determination thereof was conducted in accordance with ASTM F1921, method B on 15 mm width specimens, with layer C against layer C. The seal pressure was 0.3 N / mm2, and the dwell time 0.5 sec. The delay time was 300 ms and the clamp separation rate was 200 mm / s. The hot tack strength is expressed in N / 15 mm width.24POLYOQ76-WO-ORD 15

[0059] The data in the table above are also reflected in the Figure 2.

[0060] The results indicate that 100% hermiticity can be achieved for each of the laminates 1-4. The results further indicate that relatively thin films using LLDPE1 could be processed under a wider sealing window, whereas relatively thicker films using LLDPE2 could be processed under a wider sealing window.

Claims

24POLYOQ76-WO-ORD 16Claims1. Film laminate comprising:A. a first biaxially-oriented polypropylene (BOPP) film;B. a second biaxially-oriented polypropylene (BOPP) film;C. a polyethylene film comprising therein in this order: i. a first polyethylene layer; ii. a second polyethylene layer; and iii. a third polyethylene layer; wherein the films A, B and C are positioned in this order; wherein the first polyethylene layer (i) comprises a low-density polyethylene (LDPE) having a density of > 900 and < 930 kg / m3and a linear low-density polyethylene (LLDPE) having a density of > 912 and < 940 kg / m3; wherein the second polyethylene layer (ii) comprises the LDPE and the LLDPE; wherein the third polyethylene layer (iii) comprises an ethylene-based copolymer having a density of > 850 and < 910 kg / m3, preferably the third polyethylene layer (iii) comprises > 50.0 wt%, more preferably > 70.0 wt%, even more preferably > 75.0 wt%, of the ethylenebased polymer; wherein density is as determined in accordance with ASTM D792 (2013).

2. Film laminate according to claim 1 , wherein the polyethylene film has a thickness of > 20 pm and < 100 pm, such as > 20 pm and < 50 pm, preferably of > 20 pm and < 40 pm, or > 60 pm and < 100 pm, preferably wherein the polyethylene film is a cast film.

3. Film laminate according to any one of claims 1-2, wherein in the polyethylene film the layer (i) is a first outer layer of the polyethylene film, and wherein the layer (iii) is a second outer layer of the polyethylene film.

4. Film laminate according to ay one of claims 1-3, wherein the LDPE has a melt mass-flow rate determined at 190°C under a load of 2.16 kg (MFR2) in accordance with ASTM D1238-13 of > 0.2 and < 10.0 g / 10 min.24POLYOQ76-WO-ORD 175. Film laminate according to any one of claims 1-4, wherein the LLDPE has a melt massflow rate determined at 190°C under a load of 2.16 kg (MFR2) in accordance with ASTM D1238-13 of > 0.2 and < 10.0 g / 10 min, preferably of > 1.5 and < 3.0 g / 10 min.

6. Film laminate according to any one of claims 1-5, wherein the ethylene-based copolymer is an ethylene / 1 -octene copolymer comprising < 18.0 wt% of polymeric units derived from 1 -octene, with regard to the total weight of the ethylene-based copolymer, and wherein the ethylene-based copolymer has a molecular weight distribution Mw / Mnof > 3.0, wherein Mwis the weight average molecular weight and Mnis the number average molecular weight, as determined in accordance with ASTM D6474 (2012).

7. Film laminate according to any one of claim 1-6, wherein the ethylene-based copolymer has a fraction eluted in a-TREF below 30°C of < 10.0 wt%, preferably > 5.0 and < 10.0 wt%, as determined according to the method of the description.

8. Film laminate according to any one of claim 1-7, wherein the ethylene-based copolymer has a chemical composition distribution broadness (CCDB) of < 25.0, preferably > 15.0 and < 25.0, as determined in accordance with the method of the description.

9. Film laminate according to any one of claim 1-8, wherein the ethylene-based copolymer has a weight average molecular weight (Mw) of > 100 kg / mol, preferably > 102 and < 150 kg / mol.

10. Film laminate according to any one of claims 1-9, wherein first BOPP film has a thickness of > 10 and < 50 pm, preferably of > 20 and < 50 pm.11 . Film laminate according to any one of claims 1-10, wherein the second BOPP film is a barrier film having an oxygen transmission rate (OTR) of < 1.0 cm3 / m2day, as determined in accordance with ASTM D3985-05 at 23°C, 0% RH, and a water vapour transmission rate (WVTR) of < 1.0 g / m2day as determined in accordance with ASTM F1249-13 at 23°C, 0% RH.

12. Process for production of a film laminate according to any one of claim 1-11 , wherein the process involves: providing the first BOPP film and the second BOPP film;24POLYOQ76-WO-ORD 18 laminating the first and the second BOPP film to form a first laminate, preferably wherein the laminating occurs solvent-free; providing the polyethylene film; subjecting the polyethylene film to a corona treatment on the surface of the first polyethylene layer, preferably such that a surface tension of > 0.038 N / m is obtained, as determined in accordance with ASTM D5946-09; and laminating the first laminate and the polyethylene film to form the film laminate, preferably wherein the laminating occurs solvent-free.

13. Article comprising the film laminate according to any one of claim 1-11 , preferably wherein the article is a pouch.

14. Process for production of an article according to claim 13, wherein the process involves subjecting the film laminate according to any one of claims 1-11 to a vertical form-fill-seal process (VFFS).

15. Use of a film according to any one of claims 1-11 to improve the hermeticity as tested in accordance with ASTM D3078-94 of a form-fill-seal package.

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