Multi-layer finishing shrink film

Abstract

The present invention relates to a multilayer finished shrink film comprising at least two layers, for example at least three layers, where at least one layer (A) comprises at least (A1) a specific multimodal copolymer of ethylene and (A2) LDPE and at least one layer (B) comprises at least (B1) recycled LDPE and (B2) a specific copolymer of ethylene. The invention further relates to a method for producing the multilayer film and to the use of the multilayer film in the field of secondary packaging.

Description

Technical Field

[0001] The present invention relates to a multi-layered shrink film for finishing, said multi-layered shrink film for finishing comprising at least two layers, for example at least three layers, wherein at least one layer (A) comprises at least (A1) a specific multimodal copolymer of ethylene and (A2) LDPE, and at least one layer (B) comprises at least (B1) recycled LDPE and (B2) a specific copolymer of ethylene. The present invention further relates to a method for manufacturing said multi-layered film and to the use of said multi-layered film in the field of secondary packaging. Background Art

[0002] Nowadays, for ecological reasons and in order to reduce costs, attempts to use polymers obtained from waste materials to manufacture new products are attracting increasing attention and importance. Due to the growing environmental problems caused by plastics, the focus today is on the recycling of these plastics.

[0003] Secondary packaging (such as shrink films for finishing) does not require food approval, and a large amount of recycled material is generated by flexible applications. Due to the original material design, the best use of this material would be in flexible applications. Therefore, secondary packaging is a perfect fit for the use of recycled plastics. However, due to the lower performance of recycled materials, their use is restricted. However, multi-layered shrink films for finishing containing recycled plastics are also known in the prior art.

[0004] WO 91 / 17886A1 relates to the use of multi-layered heat-shrinkable films for advantageous high shrinkage rates but low shrinkage forces in combination with recycled waste of such films to provide multi-layered heat-shrinkable films that retain these advantageous properties. An exemplary film is a core of a blend of a certain linear low-density polyethylene and a certain highly branched low-density polyethylene sandwiched between two relatively thin outer layers of propylene / ethylene copolymers, wherein the core also contains recycled waste of the multi-layered film.

[0005] DE 20 2018 101 226 U1 relates to a packaging for bottles or cans having the following components: 1) an outer packaging for at least partially re-packaging the bottle or can, said outer packaging consisting of a heat-shrinkable plastic film, and 2) a handle fastened to the outer packaging by means of a handle attachment part, wherein all components of the packaging consist of at least one recyclable plastic, and wherein the handle attachment part consists of a printable plastic and has an imprint.

[0006] In most multi-layered shrink films for finishing, it is not possible to use more than 25% of recycled material without significantly deteriorating the mechanical properties. The increased non-uniformity of contaminants resulting from the original use, collection, and recycling of flexible materials increases the risk of forming holes in the furnace (such as a shrink furnace). Due to the non-uniformity, LDPE is the most sensitive material to hole formation.

[0007] Based on this, an object of the present invention is to provide a multi-layer finishing shrink film that allows a relatively large amount of recycled LDPE to be used with low or no pore formation. Another object of the present invention is that the multi-layer finishing shrink film exhibits very good mechanical properties without increasing the film thickness. In addition, an object of the present invention is that the multi-layer finishing shrink film has good optical properties, good shrinkage behavior, good puncture resistance, and good sealing properties. Summary of the Invention

[0008] The present invention relates to a multi-layer finishing shrink film comprising at least the following layers:

[0009] (A) A layer comprising the following components:

[0010] (A1) A multi-modal copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, the multi-modal polymer of ethylene having a density of 920 to 940 kg / m 3 , preferably 922 to 937 kg / m 3 , most preferably 925 to 935 kg / m 3 and a melt flow rate MFR2 of 0.5 to 2.0 g / 10 min, preferably 0.7 to 1.8 g / 10 min, most preferably 1.0 to 1.6 g / 10 min, and

[0011] (A2) LDPE; and

[0012] (B) A layer comprising the following components:

[0013] (B1) Recycled LDPE;

[0014] (B2) A copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, the copolymer of ethylene having a density of 930 to 970 kg / m 3 , preferably 932 to 965 kg / m 3 , most preferably 933 to 963 kg / m 3 and a melt flow rate MFR2 of 0.10 to 2.0 g / 10 min, preferably 0.11 to 1.5 g / 10 min, most preferably 0.12 to 1.0 g / 10 min.

[0015] The present invention further relates to a method for manufacturing a multi-layer finishing shrink film as described above or below, characterized in that the film is manufactured by a one-step blown film coextrusion process.

[0016] Furthermore, the present invention relates to the use of the multilayer orientation shrink film as described above or below for secondary packaging, preferably for bottles and cans, more preferably for bottles and cans in the fields of household products, food products, health care products and beverage products.

[0017] Definition:

[0018] In the context of the present invention, the term "multimodal" may refer to being multimodal with respect to the molecular weight distribution and thus also includes bimodal polymers. However, as explained in the detailed description of the components, the components may also be multimodal with respect to other properties, such as MFR and / or density.

[0019] Generally, a polymer composition comprising at least two polyethylene fractions is referred to as "multimodal", the at least two polyethylene fractions having been produced under different polymerization conditions, resulting in different (weight-average) molecular weights and molecular weight distributions of the fractions. The prefix "multi" relates to the number of different polymer fractions present in the polymer. Thus, for example, the term multimodal polymer includes the so-called "bimodal" polymers consisting of two fractions. The form of the molecular weight distribution curve of a multimodal polymer (e.g., LLDPE), i.e., the appearance of the graph of the polymer weight fraction as a function of its molecular weight, will show two or more maxima or at least be significantly broader compared to the curve of a single fraction.

[0020] Ideally, the molecular weight distribution curve of the multimodal polymer of the present invention will show two distinct maxima. For example, if the polymer is produced in a continuous multi-stage process, using reactors connected in series and different conditions in each reactor, the polymer fractions produced in the different reactors will each have their own molecular weight distribution and weight-average molecular weight. When recording the molecular weight distribution curve of such a polymer, superimposing the individual curves from these fractions into the molecular weight distribution curve of the total resulting polymer product will generally result in a curve having two or more significantly different maxima.

[0021] In any multimodal polymer, by definition, there are lower molecular weight components (LMW) and higher molecular weight components (HMW). The LMW components have a lower molecular weight than the higher molecular weight components. The difference is preferably at least 5000 g / mol.

[0022] In the context of the present invention, it is preferred that all olefins are α-olefins.

[0023] The meaning of low density polyethylene (LDPE) is well known and documented in the literature. Although the term LDPE is an abbreviation for low density polyethylene, the term is understood not to limit the density range, but rather to encompass HP polyethylene such as LDPE, which is produced by free radical polymerization in a high pressure process and has low, medium and higher densities. Compared with polyethylene produced in the presence of an olefin polymerization catalyst, the term LDPE only describes and differentiates the properties of HP polyethylene with typical characteristics, such as different branching structures. In addition, the low density polyethylene (LDPE) homopolymer may be unsaturated.

[0024] In the context of the present invention, a "shrink wrap film" is a film that is wrapped around an object to be packaged and shrunk to hold the units within the object together. The most common use of these films is to package multiple containers (articles), such as bottles or cans that may contain food, beverages, etc. The shrink wrap film is wrapped around a number of containers, perhaps a six-pack of beverages or a 24-pack of food cans, optionally held in a cardboard tray or mat, and shrunk around the containers. The wrapping process typically involves a shrink oven or a shrink tunnel in which the film and the object covered by the film are briefly heated to cause the shrink wrap to occur. The plastic film then collapses around the multiple containers and holds the units in place.

[0025] For the purposes of this specification and the following claims, the term "recycled LDPE" is used to indicate that the material is recovered from post-consumer waste and / or post-industrial waste. That is, post-consumer waste refers to an object that has completed at least its first use cycle (or life cycle), i.e., has completed its first purpose; while industrial waste refers to manufacturing waste that generally does not reach the consumer. In the context of the present invention, based on the total weight of the corresponding recycled LDPE, "recycled LDPE" may also contain up to 30 wt%, preferably up to 25 wt%, more preferably up to 20 wt% and even more preferably up to 10 wt% of other components (such as, for example, LLDPE, MDPE, HDPE) and / or additives, fillers and masterbatches.

[0026] Accordingly, the term "virgin" refers to newly produced materials and / or objects that are before their first use and have not been recycled. If the source of the polymer is not explicitly mentioned, the polymer is a "virgin" polymer.

[0027] The "density" of the materials in this specification and the claims refers to the density measured according to ISO 1183.

[0028] The "melt flow rate" (=MFR) of the polymers in this specification and the claims refers to the MFR measured according to ISO 1133.

[0029] The "melting temperature" of the polymers described in this specification and the claims can be measured using a TA Instrument Q200 differential scanning calorimeter (DSC) on a 5 to 7 mg sample. The DSC is run at a scan rate of 10 °C / min in a heating / cooling / heating cycle in the temperature range of 25 to +225 °C according to ISO 11357 / Part 3 / Method C2. The crystallization temperature (T c ) and crystallization enthalpy (H cryst ) are determined from the cooling step, while the melting temperature (T m ) and heat of fusion (H 熔化 ) are determined from the second heating step. The crystallinity is calculated from the heat of fusion, assuming an H 熔化 value of 209 J / g for fully crystalline polypropylene (see Brandrup, J., Immergut, E.H., editors, Polymer Handbook, Third Edition, Wiley, New York, 1989; Chapter 3).

[0030] When using the term "comprising" in this specification and the claims, it does not exclude other unspecified elements that are of primary or secondary functional importance. For the purposes of this invention, the term "consisting of" is considered a preferred embodiment of the term "comprising". If a group is defined hereinafter as comprising at least a certain number of embodiments, this should also be understood as disclosing a group consisting preferably only of these embodiments.

[0031] Whenever the terms "include" or "have" are used, these terms are meant to be equivalent to "comprising" as defined above.

[0032] When an indefinite or definite article is used in reference to a singular noun, e.g., "a", "an", or "the", this includes the plural form of that noun, unless otherwise specifically stated. Detailed Description

[0033] Layer (A)

[0034] Layer (A) comprises a multimodal copolymer (A1) of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms and LDPE (A2).

[0035] Preferably, based on the total weight of layer (A), the multimodal copolymer (A1) of ethylene is present in layer (A) in an amount of 15 to 90% by weight, preferably 18 to 85% by weight, and most preferably 20 to 82% by weight.

[0036] More preferably, based on the total weight of layer (A), LDPE (A2) is present in layer (A) in an amount of 10 to 85% by weight, preferably 15 to 82% by weight, and most preferably 18 to 80% by weight.

[0037] Layer (A) may contain additional polymer components different from the multimodal copolymer (A1) of ethylene and LDPE (A2). These additional polymer components are preferably polymers based on ethylene. If present, the additional polymer components are preferably present in an amount of at most 20% by weight, more preferably at most 10% by weight.

[0038] The composition forming layer (A) may further contain additives and / or admixtures.

[0039] The additives are preferably selected from the group consisting of slip agents, UV stabilizers, antioxidants, nucleating agents, and mixtures thereof. Preferably, based on the total weight of layer (A), the amount of these additives contained is in the range of 0 to 5000 ppm, preferably in the range of 10 to 5000 ppm, and more preferably in the range of 500 to 3000 ppm.

[0040] The admixtures are preferably selected from the group consisting of pigments, fillers, anti-caking agents, and mixtures thereof. Preferably, based on the total weight of layer (A), the amount of these additives contained is in the range of 0 to 5% by weight, preferably in the range of 0 to 3% by weight, more preferably in the range of 0 to 2% by weight, and most preferably in the range of 0 to 1% by weight.

[0041] In a preferred embodiment, the polymer components of layer (A) consist of a multimodal copolymer (A1) of ethylene and LDPE (A2).

[0042] In said embodiment, the weight ratio (A1:A2) of the multimodal copolymer (A1) of ethylene and LDPE (A2) is preferably in the range of 15:85 to 90:10, more preferably in the range of 18:82 to 85:15, and most preferably in the range of 20:80 to 82:18.

[0043] Furthermore, in said embodiment, the multimodal copolymer (A1) of ethylene, LDPE (A2), and optional additives and admixtures together total 100% by weight of the total weight of layer (A).

[0044] Multi-modal copolymer of ethylene (A1)

[0045] The multimodal copolymer (A1) of ethylene is a copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms.

[0046] The at least one comonomer is preferably selected from 1-butene, 1-hexene and / or 1-octene, more preferably from 1-butene and / or 1-hexene.

[0047] In a preferred embodiment, the multimodal copolymer (A1) of ethylene is a terpolymer of ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms.

[0048] The two comonomers are preferably selected from 1-butene, 1-hexene and 1-octene, more preferably from 1-butene and 1-hexene.

[0049] The term "terpolymer of ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms" means that the multimodal copolymer (A1) of ethylene contains only units derived from ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms, preferably selected from 1-butene, 1-hexene and 1-octene, more preferably from 1-butene and 1-hexene.

[0050] The multimodal copolymer (A1) of ethylene has a total comonomer content of 1.0 to 15.0% by weight, preferably 1.5 to 12.5% by weight, still more preferably 2.0 to 10.0% by weight, i.e., the content of comonomer units derived from 1-butene and / or 1-hexene.

[0051] In one embodiment, the multimodal copolymer (A1) of ethylene contains 1-butene comonomer units. In said embodiment, based on the total weight of the multimodal copolymer (A1) of ethylene, the multimodal copolymer (A1) preferably has a 1-butene content of 0.1 to 5.0% by weight, more preferably 0.2 to 3.5% by weight, still more preferably 0.3 to 2.0% by weight.

[0052] In one embodiment, the multimodal copolymer (A1) of ethylene contains 1-hexene comonomer units. In said embodiment, based on the total weight of the multimodal copolymer (A1) of ethylene, the multimodal copolymer (A1) preferably has a 1-hexene content of 2.0 to 15.0% by weight, more preferably 2.5 to 12.5% by weight, still more preferably 3.0 to 10.0% by weight.

[0053] The multimodal copolymer (A1) of ethylene can be multimodal with respect to the comonomer distribution.

[0054] This means that the multimodal copolymer (A1) of ethylene contains components with different comonomer contents.

[0055] When it is a copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene or 1-hexene), in one embodiment, the multimodal copolymer (A1) of ethylene may comprise a polyethylene homopolymer component and a copolymer component of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene or 1-hexene).

[0056] When it is a copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene or 1-hexene), in another embodiment, the multimodal copolymer (A1) of ethylene may comprise two copolymer components of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene or 1-hexene), and the two copolymer components have different comonomer contents.

[0057] When it is a terpolymer of ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene and 1-hexene), in one embodiment, the multimodal copolymer (A1) of ethylene may comprise a polyethylene homopolymer component, a copolymer component of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene), and a copolymer component of ethylene and another comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-hexene).

[0058] When it is a terpolymer of ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene and 1-hexene), in another embodiment, the multimodal copolymer (A1) of ethylene may comprise a polyethylene homopolymer component and a terpolymer component of ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene and 1-hexene).

[0059] When it is a terpolymer of ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene and 1-hexene), in yet another embodiment, the multimodal copolymer (A1) of ethylene may comprise a copolymer component of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene) and a copolymer component of ethylene and another comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-hexene).

[0060] In a preferred embodiment, the multimodal copolymer of ethylene (A1) is a terpolymer of ethylene and two comonomers selected from 1-butene and 1-hexene. Based on the total weight of the multimodal copolymer of ethylene (A1), the terpolymer has a 1-butene content of 0.1 to 5.0 wt%, preferably 0.2 to 3.5 wt%, still more preferably 0.3 to 2.0 wt% and a 1-hexene content of 2.0 to 14.9 wt%, more preferably 2.5 to 12.3 wt%, still more preferably 3.0 to 9.7 wt%.

[0061] The multimodal copolymer of ethylene (A1) has a density of 920 to 940 kg / m 3 , preferably 922 to 937 kg / m 3 , most preferably 925 to 935 kg / m 3 .

[0062] The multimodal copolymer of ethylene (A1) is preferably linear low density polyethylene (LLDPE).

[0063] The multimodal copolymer of ethylene (A1) has a melt flow rate MFR2 of 0.5 to 2.0 g / 10 min, preferably 0.7 to 1.8 g / 10 min, most preferably 1.0 to 1.6 g / 10 min.

[0064] The multimodal copolymer of ethylene (A1) preferably has a melting temperature Tm of 115 to 135 °C, more preferably 118 to 130 °C, most preferably 120 to 128 °C, determined by differential scanning calorimetry (DSC) according to ISO 11357 / Part 3 / Method C2 at a scanning rate of 10 °C / min in the temperature range of 25 to +225 °C in a heating / cooling / heating cycle.

[0065] Furthermore, the multimodal copolymer of ethylene (A1) preferably has a ratio of weight average molecular weight to number average molecular weight Mw / Mn of 2.0 to 6.0, preferably 2.5 to 5.5, more preferably 3.0 to 5.0, determined by gel permeation chromatography (GPC) according to ISO 16014-4:2003 and ASTM D 6474-12.

[0066] The multimodal copolymer of ethylene (A1) can preferably be obtained by polymerization in the presence of a single-site catalyst system. The single-site catalyst system preferably comprises a catalytically active metallocene compound or complex in combination with a cocatalyst. The metallocene compound or complex is also referred to herein as an organometallic compound (C).

[0067] The organometallic compound (C) contains a transition metal (M) of Groups 3 to 10 or the actinide or lanthanide series of the Periodic Table (IUPAC 2007).

[0068] According to the present invention, the term "organometallic compound (C)" includes any metallocene compound of a transition metal, which any metallocene compound bears at least one organic (coordinating) ligand and exhibits catalytic activity alone or in combination with a cocatalyst. Transition metal compounds are well known in the art and preferably encompass compounds of metals from Groups 3 to 10 of the Periodic Table (IUPAC 2007), such as Groups 3 to 7, or Groups 3 to 6, such as Groups 4 to 6, and the lanthanides or actinides.

[0069] In an embodiment, the organometallic compound (C) has the following formula (I):

[0070] (L) m R n MX q (I)

[0071] where

[0072] "M" is a transition metal (M) from Groups 3 to 10 of the Periodic Table (IUPAC 2007),

[0073] each "X" is independently a monoanionic ligand, such as an ortho-ligand,

[0074] each "L" is independently an organic ligand coordinated to the transition metal "M",

[0075] "R" is a bridging group connecting the organic ligands (L),

[0076] "m" is 1, 2 or 3, preferably 2,

[0077] "n" is 0, 1 or 2, preferably 1,

[0078] "q" is 1, 2 or 3, preferably 2, and

[0079] m + q equals the valence of the transition metal (M).

[0080] "M" is preferably selected from the group consisting of zirconium (Zr), hafnium (Hf) or titanium (Ti), more preferably selected from the group consisting of zirconium (Zr) and hafnium (Hf).

[0081] "X" is preferably a halogen, most preferably Cl.

[0082] Most preferably, the organometallic compound (C) is a metallocene complex which comprises a transition metal compound as defined above, said transition metal compound comprising a cyclopentadienyl, indenyl or fluorenyl ligand as substituent "L". Further, the ligand "L" may have substituents such as alkyl groups, aryl groups, aralkyl groups, alkaryl groups, silyl groups, siloxy groups, alkoxy groups or other heteroatom groups etc. Suitable metallocene catalysts are known in the art and are particularly disclosed in WO-A-95 / 12622, WO-A-96 / 32423, WO-A-97 / 28170, WO-A-98 / 32776, WO-A-99 / 61489, WO-A-03 / 010208, WO-A-03 / 051934, WO-A-03 / 051514, WO-A-2004 / 085499, EP-A-1752462 and EP-A-1739103.

[0083] The most preferred metallocene catalysts (which refer to the catalytically active metallocene complexes as defined above) are used together with a cocatalyst (also called activator). Suitable activators are alkyl metal compounds known in the art, especially alkyl aluminum compounds. Particularly suitable activators for use with metallocene catalysts are alkyl aluminum oxides such as methylaluminoxane (MAO), tetra-isobutylaluminoxane (TIBAO) or hexa-isobutylaluminoxane (HIBAO).

[0084] The multimodal copolymer of ethylene (A1) can be produced by any suitable polymerization method known in the art, said polymerization method comprising at least one polymerization stage, wherein the polymerization is generally carried out in solution, slurry, bulk or gas phase. Preferably, the multimodal copolymer of ethylene (A1) is produced in a multi-stage polymerization method comprising at least two polymerization zones.

[0085] The first ethylene polymer component is preferably produced in the first polymerization zone, and the second ethylene polymer component is preferably produced in the second polymerization zone. The first polymerization zone and the second polymerization zone can be connected in any order, i.e. the first polymerization zone can be before the second polymerization zone, or the second polymerization zone can be before the first polymerization zone, or alternatively, the polymerization zones can be connected in parallel. However, it is preferred to operate the polymerization zones in a cascade mode. The polymerization zones can be operated under slurry, solution or gas phase conditions or a combination thereof.

[0086] Suitable processes comprising cascade slurry and gas phase polymerization stages are particularly disclosed in WO-A-92 / 12182 and WO-A-96 / 18662.

[0087] It is generally preferred to remove the reactants from the previous polymerization stage from the polymer and then introduce them into the subsequent polymerization stage. This is preferably carried out when transferring the polymer from one polymerization stage to another.

[0088] The catalyst can be transferred into the polymerization zone by any means known in the art. For example, the catalyst can be suspended in a diluent and maintained as a homogeneous slurry to mix the catalyst with the viscous mixture of fats and oils and feed the resulting paste into the polymerization zone, or let the catalyst settle and introduce a portion of the resulting catalyst slurry into the polymerization zone.

[0089] The polymerization in the first polymerization zone is preferably carried out in a slurry. Then, the polymer particles formed in the polymerization are suspended in a fluid hydrocarbon together with the catalyst that has fragmented and dispersed within the particles. The slurry is agitated to transfer the reactants from the fluid to the particles.

[0090] The polymerization is generally carried out in an inert diluent, usually a hydrocarbon diluent such as methane, ethane, propane, n-butane, isobutane, pentane, hexane, heptane, octane, etc., or a mixture thereof. Preferably, the diluent is a low-boiling hydrocarbon having 1 to 4 carbon atoms or a mixture of such hydrocarbons, and the preferred diluent is propane.

[0091] The ethylene content in the fluid phase of the slurry can be 2 to about 50 mol%, preferably about 2 to about 20 mol% and especially about 3 to about 12 mol%.

[0092] The temperature in the slurry polymerization is generally 50 to 115 °C, preferably 60 to 110 °C and especially 70 to 100 °C. The pressure is 1 to 150 bar, preferably 10 to 100 bar.

[0093] The slurry polymerization can be carried out in any known reactor for slurry polymerization.

[0094] The reactor includes a continuous stirred tank reactor and a loop reactor. It is particularly preferred to carry out the polymerization in a loop reactor. In such a reactor, the slurry is circulated at high speed along a closed pipeline using a circulation pump. Loop reactors are generally known in the art, and examples are given, for example, in US-A-4582816, US-A-3405109, US-A-3324093, EP-A-479186 and US-A-5391654.

[0095] Sometimes it is advantageous to carry out the slurry polymerization above the critical temperature and pressure of the fluid mixture. Such an operation is described in US-A-5391654. In such an operation, the temperature is generally 80 to 110 °C, preferably 85 to 105 °C, and the pressure is 30 to 150 bar, preferably 50 to 100 bar.

[0096] The slurry can be withdrawn from the reactor continuously or intermittently. A preferred way of intermittent withdrawal is to use a settling leg, in which the slurry is allowed to concentrate and then a batch of the concentrated slurry is withdrawn from the reactor. Continuous withdrawal is advantageously combined with a suitable concentration method, such as those disclosed in EP-A-1310295 and EP-A-1591460.

[0097] As is known in the art, hydrogen can be fed into the reactor to control the molecular weight of the polymer. In addition, one or more comonomers selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene and / or 1-hexene) can be added to the reactor, for example to control the density of the polymer product. The actual amounts of such hydrogen and comonomer feeds depend on the catalyst used and the desired melt index (or molecular weight) and density (or comonomer content) of the resulting polymer.

[0098] The polymerization in the second polymerization zone is preferably carried out in the gas phase, preferably in a fluidized bed reactor, in a fast fluidized bed reactor or in a slurry bed reactor or in any combination of these reactors. The polymerization in the second polymerization zone is more preferably carried out in a fluidized bed gas phase reactor, in which ethylene and one or more comonomers selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene and / or 1-hexene) are polymerized together in an upwardly flowing gas stream in the presence of a polymerization catalyst and preferably in the presence of the reaction mixture from the first polymerization zone. The reactor generally includes a fluidized bed, which includes growing polymer particles containing active catalyst located above a fluidization grid.

[0099] The polymer bed is fluidized with the aid of a fluidizing gas, which includes an olefin monomer, an optional (one or more) comonomer, an optional chain growth control agent or chain transfer agent (such as hydrogen) and an optional inert gas. The fluidizing gas is introduced into an inlet chamber at the bottom of the reactor. One or more of the above components can be continuously added to the fluidizing gas to compensate for losses caused especially by the reaction or product withdrawal.

[0100] The fluidizing gas passes through the fluidized bed. The superficial velocity of the fluidizing gas must be higher than the minimum fluidization velocity of the particles contained in the fluidized bed, otherwise fluidization will not occur. On the other hand, the velocity of the gas should be lower than the incipient velocity of pneumatic conveying, otherwise the entire bed will be entrained by the fluidizing gas.

[0101] When the fluidizing gas contacts the bed containing the active catalyst, the reactive components in the gas (such as monomers and chain transfer agents) react in the presence of the catalyst to produce a polymer product. At the same time, the gas is heated by the heat of reaction.

[0102] Unreacted fluidizing gas is removed from the top of the reactor and cooled in a heat exchanger to remove the heat of reaction. The gas is cooled to a temperature below that of the bed to prevent the bed from heating up due to the reaction. The gas can be cooled to a temperature such that part of the gas condenses. When the droplets enter the reaction zone, they vaporize.

[0103] Then, the heat of vaporization helps to remove the heat of reaction. This mode of operation is known as the condensation mode, and variants thereof are disclosed in particular in WO-A-2007 / 025640, USA-4543399, EP-A-699213 and WO-A-94 / 25495. As disclosed in EP-A-696293, a condensing agent can also be added to the recycle gas stream. The condensing agent is a non-polymerizable component such as n-pentane, isopentane, n-butane or isobutane, which condenses at least partially in the cooler.

[0104] The gas is then compressed and recycled to the inlet chamber of the reactor. Before entering the reactor, fresh reactants are introduced into the fluidizing gas stream to compensate for the losses due to reaction and product withdrawal. Generally, it is known to analyze the composition of the fluidizing gas and introduce gas components to keep the composition constant. The actual composition is determined by the desired properties of the product and the catalyst used in the polymerization.

[0105] The catalyst can be introduced into the reactor continuously or intermittently in various ways. When the gas-phase reactor is part of a reactor cascade, the catalyst is usually dispersed in the polymer particles of the previous polymerization stage. The polymer particles can be introduced into the gas-phase reactor as disclosed in EP-A-1415999 and WO-A-00 / 26258. In particular, if the previous reactor is a slurry reactor, it is advantageous to feed the slurry directly into the fluidized bed of the gas-phase reactor as disclosed in EP-A-887379, EP-A-887380, EP-A-887381 and EP-A-991684.

[0106] The polymer product can be withdrawn from the gas-phase reactor continuously or intermittently. Combinations of these methods can also be used. Continuous withdrawal is disclosed in particular in WO-A-OO / 29452. Intermittent withdrawal is disclosed in particular in US-A-4621952, EP-A-188125, EP-A-250169 and EP-A-579426.

[0107] If desired, (one or more) antistatic agents such as water, ketones, aldehydes and alcohols can also be introduced into the gas-phase reactor. The reactor can also include a mechanical stirrer to further promote mixing within the fluidized bed.

[0108] Typically, a fluidized bed polymerization reactor operates at a temperature in the range of 50 to 100 °C, preferably in the range of 65 to 90 °C. The pressure is suitably 10 to 40 bar, preferably 15 to 30 bar.

[0109] Before the polymerization of the first ethylene polymer component and the second ethylene polymer component in the first polymerization zone and the second polymerization zone, a prepolymerization step can be carried out. The purpose of prepolymerization is to polymerize a small amount of polymer onto the catalyst at low temperature and / or low monomer concentration. By prepolymerization, the performance of the catalyst in the slurry can be improved and / or the properties of the final polymer can be changed.

[0110] The prepolymerization step can be carried out in slurry or in the gas phase. Preferably, prepolymerization is carried out in slurry, preferably in a loop reactor. Then, prepolymerization is preferably carried out in an inert diluent, preferably the diluent is a low-boiling hydrocarbon having 1 to 4 carbon atoms or a mixture of such hydrocarbons.

[0111] The temperature in the prepolymerization step is generally 0 to 90 °C, preferably 20 to 80 °C, more preferably 25 to 70 °C.

[0112] The pressure is not critical and is generally 1 to 150 bar, preferably 10 to 100 bar.

[0113] Preferably, all the catalyst components are introduced into the prepolymerization step.

[0114] Preferably, then the reaction product of the prepolymerization step is introduced into the first polymerization zone.

[0115] The multimodal copolymer (A1) of ethylene obtained by a multi-stage process can be extruded and pelletized, and then blended with LDPE (A2) in pellet form.

[0116] The multimodal copolymer (A1) of ethylene obtained by a multi-stage process can also be blended with LDPE (A2) in powder form.

[0117] The multimodal copolymer (A1) of ethylene is preferably the virgin polymer.

[0118] LDPE (A2)

[0119] Preferably, LDPE (A2) has a density of 915 to 935 kg / m 3 ³, preferably 917 to 932 kg / m 3 ³, and most preferably 920 to 930 kg / m 3 ³.

[0120] Further preferably, LDPE (A2) has a melt flow rate MFR2 of 0.1 to 2.0 g / 10 min, preferably 0.2 to 1.5 g / 10 min, and most preferably 0.3 to 1.2 g / 10 min.

[0121] LDPE (A2) preferably comprises virgin LDPE, recycled LDPE, or a mixture of virgin LDPE and recycled LDPE.

[0122] In the first embodiment, LDPE (A2) consists of virgin LDPE.

[0123] In the second embodiment, LDPE consists of recycled LDPE.

[0124] In the third embodiment, LDPE consists of a mixture of virgin LDPE and recycled LDPE.

[0125] In the said third embodiment, the weight ratio of virgin LDPE to recycled LDPE in the mixture is preferably in the range of 5:1 to 1:2, more preferably in the range of 4:1 to 1:1, and most preferably in the range of 3:1 to 2:1.

[0126] Virgin LDPE is preferably a homopolymer of ethylene.

[0127] Recycled LDPE preferably has the same properties, more preferably the same as the recycled LDPE (B1) described below.

[0128] Virgin LDPE that meets the requirements of LDPE (A2) described above or below is known and can be purchased from suppliers such as Borouge or Borealis.

[0129] Recycled LDPE that meets the requirements of LDPE (A2) described above or below is known and can be purchased from suppliers such as Suzhou Jinhui Technology or Plaspulp.

[0130] Layer (B)

[0131] Layer (B) comprises recycled LDPE (B1) and a copolymer (B2) of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms.

[0132] Preferably, based on the total weight of layer (B), recycled LDPE (B1) is present in layer (B) in an amount of 20 to 85 wt%, preferably 25 to 80 wt%, and most preferably 27 to 77 wt%.

[0133] More preferably, based on the total weight of layer (B), the copolymer (B2) of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms is present in layer (B) in an amount of 15 to 80% by weight, preferably 20 to 75% by weight, and most preferably 23 to 73% by weight.

[0134] Layer (B) may further comprise

[0135] (B3) a multimodal polymer of ethylene and at least two different comonomers selected from α-olefins having 4 to 10 carbon atoms, the multimodal polymer of ethylene having a density of 910 to 930 kg / m 3 , preferably 912 to 927 kg / m 3 , and most preferably 915 to 925 kg / m 3 and a melt flow rate MFR2 of 0.5 to 2.5 g / 10 min, preferably 1.0 to 2.0 g / 10 min, and most preferably 1.2 to 1.8 g / 10 min.

[0136] If present, based on the total weight of layer (B), the multimodal copolymer (B3) of ethylene and at least two different comonomers selected from α-olefins having 4 to 10 carbon atoms is preferably present in layer (B) in an amount of 10 to 30% by weight, preferably 15 to 28% by weight, and most preferably 20 to 26% by weight.

[0137] Layer (B) may contain additional polymer components different from the recycled LDPE (B1), the copolymer of ethylene (B2), and optionally the multimodal copolymer of ethylene (B3). These additional polymer components are preferably ethylene-based polymers. If present, the additional polymer components are preferably present in an amount of at most 20% by weight, more preferably at most 10% by weight.

[0138] The composition forming layer (B) may further comprise additives and / or admixtures.

[0139] The additives are preferably selected from the group consisting of slip agents, UV stabilizers, antioxidants, nucleating agents, and mixtures thereof. Preferably, based on the total weight of layer (B), the amount of these additives included is in the range of 0 to 5000 ppm, preferably in the range of 10 to 5000 ppm, and more preferably in the range of 500 to 3000 ppm.

[0140] The admixtures are preferably selected from the group consisting of pigments, fillers, anti-caking agents, and mixtures thereof. Preferably, based on the total weight of layer (B), the amount of these additives included is in the range of 0 to 5% by weight, preferably in the range of 0 to 3% by weight, more preferably in the range of 0 to 2% by weight, and most preferably in the range of 0 to 1% by weight.

[0141] In one embodiment, the polymer component of layer (B) consists of recycled LDPE (B1) and a copolymer of ethylene (B2).

[0142] In said embodiment, based on the total weight of layer (B), recycled LDPE (B1) is preferably present in layer (B) in an amount of 20 to 85% by weight, preferably 25 to 80% by weight, most preferably 27 to 77% by weight.

[0143] Further, in said embodiment, based on the total weight of layer (B), the copolymer of ethylene (B2) is preferably present in layer (B) in an amount of 15 to 80% by weight, preferably 20 to 75% by weight, most preferably 23 to 73% by weight.

[0144] The weight ratio (B1:B2) of recycled LDPE (B1) and the copolymer of ethylene (B2) is preferably in the range of 20:80 to 85:15, more preferably in the range of 25:75 to 80:20, most preferably in the range of 27:73 to 77:23.

[0145] Further, in said embodiment, recycled LDPE (B1), the copolymer of ethylene (B2) and optional additives and extenders together amount to 100% by weight of the total weight of layer (B).

[0146] In another embodiment, the polymer component of layer (B) consists of recycled LDPE (B1), a copolymer of ethylene (B2) and a multimodal copolymer of ethylene (B3).

[0147] In said embodiment, based on the total weight of layer (B), recycled LDPE (B1) is preferably present in layer (B) in an amount of 20 to 75% by weight, preferably 25 to 65% by weight, most preferably 27 to 57% by weight.

[0148] Further, in said embodiment, based on the total weight of layer (B), the copolymer of ethylene (B2) is preferably present in layer (B) in an amount of 15 to 50% by weight, preferably 20 to 35% by weight, most preferably 23 to 30% by weight.

[0149] Still further, in said embodiment, based on the total weight of layer (B), the multimodal copolymer of ethylene (B3) is preferably present in layer (B) in an amount of 10 to 30% by weight, preferably 15 to 28% by weight, most preferably 20 to 26% by weight.

[0150] The weight ratio (B1: B2 + B3) of the weight of the combination of the recycled LDPE (B1), the copolymer of ethylene (B2), and the multimodal copolymer of ethylene (B3) is preferably in the range of 20:80 to 75:25, more preferably in the range of 25:75 to 65:35, and most preferably in the range of 27:73 to 57:43.

[0151] Further, in the said embodiment, the recycled LDPE (B1), the copolymer of ethylene (B2), the multimodal copolymer of ethylene (B3), and optional additives and dopants together amount to 100% by weight of the total weight of layer (B).

[0152] Recycled LDPE (B1)

[0153] The recycled LDPE (B1) preferably originates from post-consumer waste or post-industrial waste, preferably from post-consumer waste.

[0154] The recycled LDPE (B1) may contain up to 20% by weight of components from the first use. The type and amount of these components will affect the physical properties of the recycled LDPE (B1). The properties given below refer to the main components.

[0155] The recycled LDPE (B1) preferably has a density of 915 to 935 kg / m 3 , more preferably 917 to 932 kg / m 3 , and most preferably 920 to 930 kg / m 3 of the density.

[0156] Further, the recycled LDPE (B1) preferably has a melt flow rate MFR2 of 0.1 to 2.0 g / 10 min, more preferably 0.3 to 1.7 g / 10 min, and most preferably 0.5 to 1.5 g / 10 min.

[0157] Still further, the recycled LDPE (B1) preferably has a tensile modulus of 200 to 450 MPa, preferably 225 to 425 MPa, and most preferably 250 to 400 MPa.

[0158] Further, the recycled LDPE (B1) preferably has a yield tensile stress of 6.0 to 15.0 MPa, more preferably 7.5 to 12.5 MPa, and most preferably 9.0 to 11.5 MPa.

[0159] Still further, the recycled LDPE (B1) preferably has a tensile strain at break of 350 to 1200%, more preferably 375 to 1100%, and most preferably 400 to 1000%.

[0160] In addition, the recycled LDPE (B1) preferably has a flexural modulus of from 200 to 500 MPa, more preferably from 225 to 475 MPa, and most preferably from 250 to 450 MPa.

[0161] Furthermore, the recycled LDPE (B1) preferably has a Charpy notched impact strength at 23 °C of from 40 to 120 kJ / m 2 , more preferably from 45 to 110 kJ / m 2 , and most preferably from 50 to 100 kJ / m 2 .

[0162] Even further, the recycled LDPE (B1) preferably has a Charpy notched impact strength at -20 °C of from 5.0 to 20.0 kJ / m 2 , more preferably from 6.0 to 18.0 kJ / m 2 , and most preferably from 7.0 to 16.0 kJ / m 2 .

[0163] In addition, the recycled LDPE (B1) preferably has a strain hardening factor of from 1.5 to 5.0, more preferably from 1.8 to 4.5, when measured at a strain rate of 3.0 s -1 at 180 °C and a Hencky strain of 2.5.

[0164] Recycled LDPE that meets the requirements of the recycled LDPE (B1) as described above or below is known and can be purchased from suppliers such as Suzhou Jinhui Technology or Plaspulp.

[0165] Copolymer of ethylene (B2)

[0166] The copolymer of ethylene (B2) is a copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms.

[0167] The comonomer is preferably selected from 1-butene, 1-hexene or 1-octene, and more preferably from 1-butene or 1-hexene.

[0168] The term "copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms" means that the copolymer of ethylene (B2) contains only units derived from ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, preferably selected from 1-butene, 1-hexene or 1-octene, and more preferably from 1-butene or 1-hexene.

[0169] The copolymer of ethylene (B2) has a total comonomer content of from 0.1 to 15.0% by weight, preferably from 0.15 to 12.5% by weight, and still more preferably from 0.2 to 10.0% by weight.

[0170] In one embodiment, the copolymer (B2) of ethylene is a copolymer of ethylene and 1-butene comonomer units, where the 1-butene comonomer units are the only comonomer units present in the copolymer (B2) of ethylene. In said embodiment, based on the total weight of the copolymer (B2) of ethylene, the copolymer (B2) of ethylene preferably has a 1-butene content of 0.1 to 10.0 wt%, more preferably 0.15 to 9.0 wt%, still more preferably 0.2 to 8.0 wt%.

[0171] In one embodiment, the copolymer (B2) of ethylene is a copolymer of ethylene and 1-hexene comonomer units, where the 1-hexene comonomer units are the only comonomer units present in the copolymer (B2) of ethylene. In said embodiment, based on the total weight of the copolymer (B2) of ethylene, the copolymer (B2) of ethylene preferably has a 1-hexene content of 0.1 to 15.0 wt%, more preferably 0.15 to 12.5 wt%, still more preferably 0.2 to 10.0 wt%.

[0172] The copolymer (B2) of ethylene can be unimodal with respect to comonomer distribution. This means that the comonomers selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene or 1-hexene) are uniformly distributed in the copolymer (B2) of ethylene.

[0173] The copolymer (B2) of ethylene can be multimodal with respect to comonomer distribution.

[0174] This means that the copolymer (B2) of ethylene contains components with different comonomer contents.

[0175] In one embodiment, the copolymer (B2) of ethylene can contain a polyethylene homopolymer component and a copolymer component of ethylene and one comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene or 1-hexene).

[0176] In another embodiment, the copolymer (B2) of ethylene can contain two copolymer components of ethylene and one comonomer selected from α-olefins having 4 to 10 carbon atoms (such as 1-butene or 1-hexene), and the two copolymer components have different comonomer contents.

[0177] The copolymer (B2) of ethylene has a melt flow rate MFR2 of 0.10 to 2.0 g / 10 min, preferably 0.11 to 1.5 g / 10 min, and most preferably 0.12 to 1.0 g / 10 min.

[0178] Furthermore, the copolymer (B2) of ethylene has 930 to 970 kg / m 3 and preferably 932 to 965 kg / m3 , most preferably 933 to 963 kg / m 3 density.

[0179] In one embodiment, the copolymer (B2) of ethylene is a medium-density copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, the medium-density copolymer having 930 to 945 kg / m 3 , preferably 932 to 942 kg / m 3 , most preferably 933 to 940 kg / m 3 density.

[0180] The medium-density copolymer preferably has a melt flow rate MFR2 of 0.10 to 0.50 g / 10 min, preferably 0.10 to 0.40 g / 10 min, and most preferably 0.12 to 0.30 g / 10 min.

[0181] In another embodiment, the copolymer (B2) of ethylene is a high-density copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, the high-density copolymer having 950 to 970 kg / m 3 , preferably 952 to 965 kg / m 3 , most preferably 955 to 963 kg / m 3 density.

[0182] The high-density copolymer preferably has a melt flow rate MFR2 of 0.30 to 2.0 g / 10 min, preferably 0.40 to 1.5 g / 10 min, and most preferably 0.50 to 1.0 g / 10 min.

[0183] In yet another embodiment, the copolymer (B2) of ethylene is a mixture of the medium-density copolymer of ethylene and the high-density copolymer of ethylene.

[0184] The copolymer (B2) of ethylene preferably has a melting temperature Tm of 120 to 140 °C, more preferably 122 to 138 °C, and most preferably 125 to 135 °C, determined by differential scanning calorimetry (DSC) analysis according to ISO 11357 / Part 3 / Method C2 at a scanning rate of 10 °C / min in the temperature range of 25 to +225 °C in a heating / cooling / heating cycle.

[0185] Copolymers of ethylene that meet the requirements of the copolymer (B2) of ethylene described above or below are known and can be purchased from suppliers such as Borouge or Borealis.

[0186] Multi-modal copolymer of ethylene (B3)

[0187] The optional multimodal copolymer of ethylene (B3) is a multimodal polymer of ethylene and at least two different comonomers selected from α-olefins having 4 to 10 carbon atoms.

[0188] The at least two comonomers are preferably selected from 1-butene, 1-hexene, and 1-octene, and more preferably from 1-butane and 1-hexene.

[0189] In a preferred embodiment, the multimodal copolymer of ethylene (B3) is a terpolymer of ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms.

[0190] The two comonomers are preferably selected from 1-butene, 1-hexene, and 1-octene, and more preferably from 1-butane and 1-hexene.

[0191] The term "terpolymer of ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms" means that the multimodal copolymer of ethylene (B3) contains only units derived from ethylene and two comonomers selected from α-olefins having 4 to 10 carbon atoms, preferably selected from 1-butene, 1-hexene, and 1-octene, and more preferably from 1-butene and 1-hexene.

[0192] The multimodal copolymer of ethylene (B3) preferably contains an ethylene-1-butene copolymer component (i) and an ethylene-1-hexene copolymer component, where 1-butene and 1-hexene are the only comonomers present in their respective components. More preferably, the copolymers (i) and (ii) have different MFR values and / or different densities. In addition, it is preferred that the copolymer (i) has a higher density than the copolymer (ii).

[0193] The multimodal copolymer of ethylene (B3) is preferably a terpolymer containing an ethylene-1-butene copolymer (i) and an ethylene-1-hexene copolymer (ii).

[0194] The multimodal copolymer of ethylene (B3) preferably has an MFR2 measured according to ISO 1133 at 190 °C under a load of 2.16 kg in the range of 0.5 to 2.5 g / 10 min, preferably in the range of 1.0 to 2.0 g / 10 min, and more preferably in the range of 1.2 to 1.8 g / 10 min.

[0195] Furthermore, the multimodal copolymer of ethylene (B3) preferably has an MFR in the range of 13 to 35, preferably in the range of 15 to 30, and more preferably in the range of 15 to 25 21 / MFR2 (MFR 21 is measured at 190 °C under a load of 21.6 kg).

[0196] Furthermore, the multimodal copolymer of ethylene (B3) preferably has an MWD (molecular weight distribution) in the range of 2 to 7, preferably in the range of 2 to 6, more preferably in the range of 2 to 5.

[0197] In addition, the multimodal copolymer of ethylene (B3) preferably has one or more of the following characteristics:

[0198] a) MFR2 of 0.5 to 2.5 g / 10 min (at 190 °C under a load of 2.16 kg according to ISO 1133);

[0199] b) MFR of 13 to 35 21 / MFR2 (MFR 21 at 190 °C under a load of 21.6 kg);

[0200] c) MWD of 5 or less, preferably between 2 and 5.

[0201] The multimodal copolymer of ethylene (B3) is preferably linear low density polyethylene (LLDPE). Even more preferably, the density of the multimodal copolymer of ethylene (B3) is in the range of 910 to 930 kg / m 3 and more preferably in the range of 915 to 925 kg / m 3 range.

[0202] The multimodal copolymer of ethylene (B3) preferably has an Mw in the range of 70,000 to 200,000 g / mol and preferably in the range of 80,000 to 150,000 g / mol.

[0203] Furthermore, based on the total amount (100% by weight) of the multimodal copolymer of ethylene (B3), the multimodal copolymer of ethylene (B3) preferably contains an ethylene copolymer component (i) in an amount in the range of 30 to 70% by weight, preferably in the range of 40 to 60% by weight, more preferably in the range of 35 to 50% by weight, more preferably in the range of 40 to 50% by weight, and an ethylene copolymer component (ii) in an amount in the range of 70 to 30% by weight, preferably in the range of 60 to 40% by weight, more preferably in the range of 50 to 65% by weight, more preferably in the range of 50 to 60% by weight.

[0204] The multimodal copolymer of ethylene (B3) preferably consists of ethylene copolymer (i) and ethylene copolymer (ii) as the only polymer components. Therefore, the split ratio between ethylene copolymer (i) and ethylene copolymer (ii) is (30 to 70):(70 to 30), preferably (40 to 60):(60 to 40), more preferably (35 to 50):(65 to 50), most preferably (40 to 50):(50 to 60), by weight.

[0205] The multimodal copolymer of ethylene (B3) preferably comprises a copolymer (i) of lower Mw and a copolymer (ii) of higher molecular weight.

[0206] The copolymer (i) preferably has an MFR2 of from 1 to 50 g / 10 min, preferably from 1 to 40 g / 10 min, more preferably from 1 to 30 g / 10 min, more preferably from 2 to 20 g / 10 min, most preferably from 2 to 15 g / 10 min, and even more preferably from 2 to 10 g / 10 min.

[0207] More preferably, the ethylene copolymer (i) has a higher MFR2 than the ethylene copolymer (ii). Even more preferably, the ratio of the MFR2 of the ethylene copolymer (i) to the MFR2 of the ethylene copolymer (ii) is from 2 to 50, preferably from 5 to 40, more preferably from 10 to 30, and most preferably from 10 to 25.

[0208] Furthermore, the ratio of the MFR2 of the ethylene copolymer (i) to the MFR2 of the final multimodal copolymer of ethylene (B3) is preferably in the range of from 1 to 15, more preferably in the range of from 1.5 to 12, more preferably in the range of from 2 to 10, and most preferably in the range of from 3 to 8.

[0209] If the MFR2 of the ethylene polymer copolymer (e.g., copolymer (ii)) cannot be measured because it cannot be separated from the mixture of at least the ethylene copolymers (i) and (ii), it can be calculated using the logarithmic mixing rule.

[0210] Of course, in addition to the multimodality with respect to the MFRs of the ethylene copolymers (i) and (ii), i.e., the difference therebetween, the multimodal copolymer of ethylene (B3) can also be multimodal, for example, with respect to one or both of two other properties:

[0211] Multimodality with respect to the type of comonomer or the (one or more) comonomer contents present in the ethylene copolymers (i) and (ii), or both the type and the (one or more) contents of the comonomers present in the ethylene copolymers (i) and (ii), i.e., the difference therebetween; and / or

[0212] The density of the ethylene copolymers (i) and (ii).

[0213] Preferably, the ethylene multi-modal copolymer (B3) is further multi-modal with respect to the comonomer type and / or the comonomer content (mol %), preferably, wherein the α-olefin comonomer having 4 to 10 carbon atoms in the ethylene copolymer (i) is different from the α-olefin comonomer having 4 to 10 carbon atoms in the ethylene copolymer (ii), preferably, wherein the α-olefin comonomer having 4 to 10 carbon atoms in the ethylene copolymer (i) is 1-butene, and the α-olefin comonomer having 4 to 10 carbon atoms in the ethylene copolymer (ii) is 1-hexene.

[0214] Preferably, the ratio of [the amount (mol %) of the α-olefin comonomer having 4 to 10 carbon atoms in the ethylene copolymer (i)] to [the amount (mol %) of at least two α-olefin comonomers having 4 to 10 carbon atoms in the final ethylene multi-modal polymer B3] is 0.10 to 0.6, preferably 0.15 to 0.5, more preferably the ethylene copolymer (i) has a lower comonomer amount (mol %) than the ethylene copolymer (ii).

[0215] The comonomer content of the copolymers (i) and (ii) can be measured, or, if and preferably in the so-called multi-stage process, first one component is produced and thereafter the other component is produced in the presence of the first component, then the comonomer content of the first-produced copolymer (e.g., copolymer (i)) can be measured, and the comonomer content of the other copolymer (e.g., copolymer (ii)) can be calculated according to the following formula:

[0216] Comonomer content (mol %) in copolymer (ii) = (Comonomer content (mol %) in the final product - (Weight fraction of copolymer (i) * Comonomer content (mol %) in copolymer (i))) / (Weight fraction of copolymer (ii))

[0217] The copolymers (i) and (ii) can be produced in the same or different reactors.

[0218] According to another preferred embodiment of the present invention, the amount (mol %) of the α-olefin comonomer having 4 to 10 carbon atoms present in the ethylene copolymer (i) is in the range of 0.03 to 5.0 mol %, preferably in the range of 0.05 to 4.0 mol %, more preferably in the range of 0.1 to 3.0 mol %, even more preferably in the range of 0.1% to 2.0 mol %, more preferably in the range of 0.15 to 1.5 mol % and even most preferably in the range of 0.15 to 1.0 mol %.

[0219] More preferably, the total amount of comonomers present in the multimodal copolymer (B3) of ethylene is in the range of 0.5 to 10 mol%, preferably in the range of 1.0 to 8 mol%, more preferably in the range of 1.0 to 5 mol% and even more preferably in the range of 1.5 to 5.0 mol%.

[0220] The multimodal copolymer (B3) of ethylene is further multimodal with respect to the density difference between the ethylene copolymer (i) and the ethylene copolymer (ii). Preferably, the density of the ethylene copolymer (i) is different from the density of the ethylene copolymer (ii), preferably the density of the ethylene copolymer (i) is higher than the density of the ethylene copolymer (ii). More preferably, the density of the ethylene copolymer (i) is in the range of 925 to 950 kg / m 3 and preferably in the range of 930 to 945 kg / m 3 range.

[0221] In a preferred embodiment, the multimodal copolymer (B3) of ethylene comprises at least the following components:

[0222] - an ethylene copolymer (i) and

[0223] - an ethylene copolymer (ii), wherein the MFR2 of the ethylene copolymer (i) is higher than the MFR2 of the ethylene copolymer (ii), preferably, wherein the ratio of the MFR2 of the ethylene polymer component (i) to the MFR2 of the ethylene polymer component (ii) is in the range of 2 to 50, preferably in the range of 5 to 40 and more preferably in the range of 10 to 30 and / or wherein the ratio of the MFR2 of the ethylene copolymer (i) to the MFR2 of the final multimodal copolymer (B3) of ethylene is in the range of 1 to 15, preferably in the range of 1.5 to 12, more preferably in the range of 2 to 10, most preferably in the range of 3 to 8.

[0224] Preferably, the density of the multimodal copolymer (B3) of ethylene is in the range of 910 to 930 kg / m 3 range and the MFR2 is in the range of 0.5 to 2.5 g / 10 min.

[0225] Preferably, the multimodal polymer of ethylene has a density of 910 to 930 kg / m 3 , preferably 912 to 927 kg / m 3 , most preferably 915 to 925 kg / m 3 and a melt flow rate MFR2 of 0.5 to 2.5 g / 10 min, more preferably 1.0 to 2.0 g / 10 min, most preferably 1.2 to 1.8 g / 10 min.

[0226] The multimodal copolymer (B3) of ethylene is preferably produced using a single-site catalyst, preferably using the same single-site catalyst to produce the ethylene copolymer.

[0227] Furthermore, preferably, the multimodal copolymer of ethylene (B3) is bimodal.

[0228] Such multimodal ethylene terpolymers are disclosed, for example, in WO 2016 / 083208. Regarding the definition of these ethylene terpolymers (such as the "morphology" of the polymer) and the production method, reference is made to WO2016 / 083208. Furthermore, all embodiments and preferred embodiments of such ethylene terpolymers with a density in the range of 910 to 930 kg / m 3 are also preferred embodiments of the multimodal ethylene terpolymers in the present disclosure, whether or not explicitly described herein.

[0229] The multimodal copolymer of ethylene (B3) is preferably the virgin polymer.

[0230] Copolymers of ethylene that meet the requirements of the copolymer of ethylene (B3) described above or below are known and can be purchased from suppliers such as Borouge or Borealis.

[0231] Orientation shrink film

[0232] The multilayer finishing shrink film of the present invention comprises at least the layers (A) and (B) described above or below.

[0233] Preferably, the multilayer finishing shrink film comprises at most seven layers, preferably at most five layers, and most preferably consists of 3 layers.

[0234] In one embodiment, the film further comprises additional layers, such as a sub-inner surface layer (I1) and / or a sub-outer surface layer (O1), wherein the sub-inner surface layer (I1) is present between the inner surface layer (A) and the core layer (B), and the sub-outer surface layer (O1) is present between the outer surface layer (A) and the core layer (B). Optionally, for a five-layer or seven-layer film, the film comprises more than one layer of any of the layers O1, B, I1, or A.

[0235] Therefore, the layer (B) is preferably the core layer, and the layer (A) is preferably the outer layer in adhesive contact with the core layer (B).

[0236] For a three-layer film, preferably, the layer (B) is the core layer sandwiched between two layers (A), and both of the two layers (A) are preferably in adhesive contact with the respective surfaces of the core layer (B).

[0237] In this context, "adhesive contact" means that there is no additional layer between the layer (B) and the layer (A).

[0238] Preferably, the two layers (A) are composed of the same components and, most preferably, are identical.

[0239] In this context, "identical" means that the outer layer (A) is not only composed of the same components (content and chemical composition), but also has the same layer thickness so that the multilayer film is symmetric.

[0240] The layer (A) of the multilayer orientation shrink film preferably has a thickness in the range of 2 to 25 μm, more preferably in the range of 3 to 23 μm, and most preferably in the range of 5 to 20 μm.

[0241] The layer (B) of the multilayer orientation shrink film preferably has a thickness in the range of 10 to 100 μm, more preferably in the range of 15 to 80 μm, and most preferably in the range of 20 to 60 μm.

[0242] The total film thickness of the multilayer orientation shrink film preferably is in the range of 15 to 100 μm, more preferably in the range of 20 to 90 μm, and most preferably in the range of 25 to 80 μm.

[0243] Based on the total thickness of the multilayer orientation shrink film, the thickness of one layer (B) in the multilayer orientation shrink film is in the range of 40% to 70%, preferably in the range of 44% to 66%, and most preferably in the range of 48% to 62%.

[0244] Based on the total thickness of the multilayer orientation shrink film, the thickness of one layer (A) in the multilayer orientation shrink film, preferably the thickness of each of the two layers (A) in the multilayer orientation shrink film, is in the range of 10 to 30%, preferably in the range of 15 to 28%, and most preferably in the range of 19 to 26%.

[0245] Based on the total weight of the multilayer orientation shrink film, the total amount of recycled LDPE in the multilayer orientation shrink film is 10 to 55% by weight, preferably 12 to 53% by weight, and most preferably 15 to 50% by weight.

[0246] The recycled LDPE is present in the layer (B) and may also be present in the layer (A) as described above and below.

[0247] The multilayer orientation shrink film preferably has one or more of the following properties, or has all of the following properties:

[0248] · A longitudinal shrinkage rate of 60 to 85%, preferably 65 to 82%, and most preferably 70 to 80%; and / or

[0249] · A transverse shrinkage rate of 5 to 25%, preferably 7 to 22%, and most preferably 9 to 20%; and / or

[0250] ·Haze of 5.0 to 19.0%, preferably 7.0 to 18.0%, most preferably 8.0 to 17.0%; and / or

[0251] ·Gloss at 60° of 70 to 130, preferably 73 to 120, most preferably 75 to 110; and / or

[0252] ·Longitudinal tensile modulus of 225 to 600 MPa, preferably 240 to 550 MPa, most preferably 250 to 500 MPa; and / or

[0253] ·Transverse tensile modulus of 250 to 650 MPa, preferably 265 to 600 MPa, most preferably 275 to 550 MPa; and / or

[0254] ·Longitudinal breaking tensile stress of 12.0 to 40.0 MPa, preferably 13.0 to 38.0 MPa, most preferably 14.0 to 36.0 MPa; and / or

[0255] ·Transverse breaking tensile stress of 15.0 to 40.0 MPa, preferably 18.0 to 36.0 MPa, most preferably 20.0 to 32.0 MPa; and / or

[0256] ·Puncture energy of 0.8 to 3.0 J, preferably 0.9 to 2.5 J, most preferably 1.0 to 2.0 J; and / or

[0257] ·Sealing start temperature of 100 to 125 °C, preferably 103 to 120 °C, most preferably 105 to 115 °C.

[0258] In a first preferred embodiment, the multilayer shrink wrap film consists of a core layer (B) sandwiched between two outer layers (A), wherein

[0259] Both of the two outer layers (A) consist of the following components

[0260] (A1) A multimodal copolymer of 40 to 60% by weight, preferably 45 to 55% by weight, of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, the multimodal polymer of ethylene having a density of 920 to 940 kg / m 3 , preferably 922 to 937 kg / m 3 , most preferably 925 to 935 kg / m 3 and a melt flow rate MFR2 of 0.5 to 2.0 g / 10 min, preferably 0.7 to 1.8 g / 10 min, most preferably 1.0 to 1.6 g / 10 min;

[0261] (A2) 40 to 60% by weight, preferably 45 to 55% by weight, of LDPE,

[0262] both are based on the total weight of the outer layer (A); and

[0263] optional additives and admixtures;

[0264] wherein the compositions of the two outer layers (A) are preferably the same; and

[0265] the core layer (B) consists of the following components

[0266] (B1) 20 to 40% by weight, preferably 25 to 35% by weight of recycled LDPE;

[0267] (B2) 60 to 80% by weight, preferably 65 to 75% by weight of a copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, the copolymer of ethylene having a density of 930 to 970 kg / m 3 , preferably 932 to 965 kg / m 3 , most preferably 933 to 963 kg / m 3 and a melt flow rate MFR2 of 0.10 to 2.0 g / 10 min, preferably 0.11 to 1.5 g / 10 min, most preferably 0.12 to 1.0 g / 10 min,

[0268] both are based on the total weight of the core layer (B); and

[0269] optional additives and admixtures.

[0270] In a second preferred embodiment, the multilayer orientation shrink film consists of a core layer (B) sandwiched between two outer layers (A), wherein

[0271] both outer layers (A) consist of the following components

[0272] (A1) 70 to 90% by weight, preferably 75 to 85% by weight of a multimodal copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, the multimodal polymer of ethylene having a density of 920 to 940 kg / m 3 , preferably 922 to 937 kg / m 3 , most preferably 925 to 935 kg / m 3 and a melt flow rate MFR2 of 0.5 to 2.0 g / 10 min, preferably 0.7 to 1.8 g / 10 min, most preferably 1.0 to 1.6 g / 10 min;

[0273] (A2) 10 to 30% by weight, preferably 15 to 25% by weight of LDPE,

[0274] both are based on the total weight of the outer layer (A); and

[0275] Optional additives and admixtures;

[0276] wherein the two outer layers (A) preferably have the same composition; and

[0277] The core layer (B) consists of the following components

[0278] (B1) 40 to 60% by weight, preferably 45 to 55% by weight of recycled LDPE;

[0279] (B2) 15 to 35% by weight, preferably 20 to 30% by weight of a copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, the copolymer of ethylene having a density of 930 to 970 kg / m 3 , preferably 932 to 965 kg / m 3 , most preferably 933 to 963 kg / m 3 and a melt flow rate MFR2 of 0.10 to 2.0 g / 10 min, preferably 0.11 to 1.5 g / 10 min, most preferably 0.12 to 1.0 g / 10 min;

[0280] (B3) 15 to 35% by weight, preferably 20 to 30% by weight of a multimodal polymer of ethylene with at least two different comonomers selected from α-olefins having 4 to 10 carbon atoms, the multimodal polymer of ethylene having a density of 910 to 930 kg / m 3 , preferably 912 to 927 kg / m 3 , most preferably 915 to 925 kg / m 3 and a melt flow rate MFR2 of 0.5 to 2.5 g / 10 min, preferably 1.0 to 2.0 g / 10 min, most preferably 1.2 to 1.8 g / 10 min;

[0281] All based on the total weight of the core layer (B); and

[0282] Optional additives and admixtures.

[0283] In a third preferred embodiment, the multilayer orientation shrink film consists of a core layer (B) sandwiched between two outer layers (A), wherein

[0284] both outer layers (A) consist of the following components

[0285] (A1) 30 to 60% by weight, preferably 35 to 55% by weight of a multimodal copolymer of ethylene with at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, the multimodal polymer of ethylene having a density of 920 to 940 kg / m 3 , preferably 922 to 937 kg / m 3, most preferably 925 to 935 kg / m 3 a density of and a melt flow rate MFR2 of 0.5 to 2.0 g / 10 min, preferably 0.7 to 1.8 g / 10 min, most preferably 1.0 to 1.6 g / 10 min;

[0286] (A2) 40 to 70% by weight, preferably 45 to 65% by weight of LDPE,

[0287] both based on the total weight of the outer layer (A);

[0288] optional additives and dopants;

[0289] wherein the composition of the two outer layers (A) is preferably the same; and

[0290] the core layer (B) consists of the following components

[0291] (B1) 65 to 85% by weight, preferably 70 to 80% by weight of recycled LDPE;

[0292] (B2) 15 to 35% by weight, preferably 20 to 30% by weight of a copolymer of ethylene and a comonomer selected from alpha-olefins having 4 to 10 carbon atoms, the copolymer of ethylene having 930 to 970 kg / m 3 , preferably 932 to 965 kg / m 3 , most preferably 933 to 963 kg / m 3 a density of and a melt flow rate MFR2 of 0.10 to 2.0 g / 10 min, preferably 0.11 to 1.5 g / 10 min, most preferably 0.12 to 1.0 g / 10 min,

[0293] both based on the total weight of the core layer (B); and

[0294] optional additives and dopants.

[0295] In a fourth preferred embodiment, the multilayer oriented shrink film consists of a core layer (B) sandwiched between two outer layers (A), wherein

[0296] both outer layers (A) consist of the following components

[0297] (A1) 15 to 30% by weight, preferably 18 to 25% by weight of a multimodal copolymer of ethylene and at least one comonomer selected from alpha-olefins having 4 to 10 carbon atoms, the multimodal polymer of ethylene having 920 to 940 kg / m 3 , preferably 922 to 937 kg / m 3 , most preferably 925 to 935 kg / m 3a density and a melt flow rate MFR2 of 0.5 to 2.0 g / 10 min, preferably 0.7 to 1.8 g / 10 min, and most preferably 1.0 to 1.6 g / 10 min;

[0298] (A2) 70 to 85% by weight, preferably 75 to 82% by weight of LDPE,

[0299] both based on the total weight of the outer layer (A);

[0300] wherein LDPE (A2) consists of a mixture of virgin LDPE and recycled LDPE in a weight ratio of 2.0:1.0 to 4.0:1.0, preferably 2.5:1.0 to 3.5:1.0; and

[0301] optional additives and admixtures;

[0302] wherein the compositions of the two outer layers (A) are preferably the same; and

[0303] The core layer (B) consists of the following components

[0304] (B1) 65 to 85% by weight, preferably 70 to 80% by weight of recycled LDPE;

[0305] (B2) 15 to 35% by weight, preferably 20 to 30% by weight of a copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, the copolymer of ethylene having 930 to 970 kg / m 3 , preferably 932 to 965 kg / m 3 , most preferably 933 to 963 kg / m 3 a density and a melt flow rate MFR2 of 0.10 to 2.0 g / 10 min, preferably 0.11 to 1.5 g / 10 min, and most preferably 0.12 to 1.0 g / 10 min,

[0306] both based on the total weight of the core layer (B); and

[0307] optional additives and admixtures.

[0308] Method for manufacturing a multi-layer orientation shrink film

[0309] The present invention further relates to a method for manufacturing a multilayer oriented shrink film according to the present invention. According to a preferred embodiment, the multilayer oriented shrink film is manufactured by a one-step blown film coextrusion process.

[0310] Use of a multi-layer orientation shrink film

[0311] The multi-layer oriented shrink film according to the present invention can be used for secondary packaging, preferably for bottles and cans, more preferably for bottles and cans in the fields of household products, food, health care products, beverage products, and bottled items (bottle, or referred to as wine or milk).

[0312] The present invention will now be described with reference to the following non-limiting examples.

[0313] Examples

[0314] 1. Measurement methods

[0315] Melt flow rate

[0316] The melt flow rate (MFR) is determined according to ISO 1133 and expressed in g / 10 min. MFR represents the fluidity of the polymer and thus represents the processability of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR2 of polyethylene is determined at a temperature of 190 °C and a load of 2.16 kg.

[0317] The MFR2 of the high molecular weight ethylene polymer component polymerized in the second polymerization reactor is calculated from the MFR2 of the low molecular weight ethylene polymer component polymerized in the first polymerization reactor and the MFR2 of the base resin as follows:

[0318] LogMFR 最终 = weight % 第一 × LogMFR 第一 + weight % 第二 × LogMFR 第二

[0319] where

[0320] - "Final" refers to "polyethylene resin"

[0321] - "First" refers to the polymer component produced in the first reactor

[0322] - "Second" refers to the polymer component produced in the second reactor.

[0323] Density

[0324] The density of the polymer is measured on compression molded specimens prepared according to EN ISO 1872-2 (February 2007) according to the ISO 1183-1:2004 Method A, in kg / m 3 given.

[0325] Comonomer content

[0326] 1313C-NMR spectra were recorded on a Bruker 400 MHz spectrometer at 130 °C from samples dissolved in 1,2,4-trichlorobenzene / benzene-d6 (90 / 10 w / w). The conversion between weight % and mole % can be carried out by calculation.

[0327] DSC analysis

[0328] The melting temperature Tm and the crystallization temperature Tc were measured by differential scanning calorimetry (DSC) on a TA Instrument Q2000 for 5 to 7 mg samples. The DSC was run at a scan rate of 10 °C / min in a heating / cooling / heating cycle in the temperature range of 25 to +225 °C according to ISO 11357 / Part 3 / Method C2. The crystallization temperature was determined from the cooling step, while the melting temperature (Tm) and the melting enthalpy (Hm) were determined from the second heating step.

[0329] GPC conventional method

[0330] Unless otherwise stated, the GPC conventional method was used to measure ethylene polymers, except for LDPE.

[0331] Molecular weight averages (M z , M w and M n ), molecular weight distribution (MWD) and its width described by the polydispersity index PDI = M w / M n (where M n is the number-average molecular weight and M w is the weight-average molecular weight) were generally determined by gel permeation chromatography (GPC) according to ISO 16014-4:2003 and ASTM D 6474-12 using the following formula:

[0332]

[0333] For a constant elution volume interval ΔV i , where A i and M i are the chromatographic peak slice area and the polyolefin molecular weight (MW) associated with the elution volume V i respectively, and N is equal to the number of data points obtained from the chromatogram between the integration limits.

[0334] Use a high-temperature GPC instrument equipped with an infrared (IR) detector (IR4 or IR5 from PolymerChar, Valencia, Spain) or a differential refractometer (RI from Agilent Technologies equipped with 3x Agilent-PLgel Olexis and 1x Agilent-PLgel Olexis Guard columns). Use 1,2,4-trichlorobenzene (TCB) stabilized with 250 mg / L 2,6-di-tert-butyl-4-methylphenol as the mobile phase. The chromatographic system is operated at a column temperature of 160 °C, a detector temperature of 160 °C, and a constant flow rate of 1 mL / min. Inject 200 μL of the sample solution for each analysis. Use Agilent Cirrus software version 3.3 or PolymerChar GPC-IR control software for data collection.

[0335] Use 19 narrow MWD polystyrene (PS) standards in the range of 0.5 kg / mol to 11,500 kg / mol to calibrate the column set. Dissolve the PS standards at room temperature for several hours. The conversion from polystyrene peak molecular weight to polyolefin molecular weight is achieved by using the Mark-Houwink equation and the following Mark-Houwink constants:

[0336] K PS = 19×10 -3 mL / g, α PS = 0.655

[0337] K PE = 39×10 -3 mL / g, α PE = 0.725

[0338] Use a third-order polynomial fit to fit the calibration data.

[0339] Prepare all samples in the concentration range of approximately 1 mg / ml and dissolve them in freshly distilled TCB stabilized with 250 ppm BHT (butylated hydroxytoluene) under N2 gas purge with continuous gentle shaking at 160 °C for 3 (three) hours for PE.

[0340] Tensile properties

[0341] The tensile properties of the molded specimens are determined on samples prepared from compression-molded plates with a sample thickness of 4 mm. The tensile modulus is determined according to ISO 527-2 / 1A at 1 mm / min and 23 °C. To determine the yield tensile stress, use a speed of 50 mm / min.

[0342] The longitudinal (MD) tensile modulus and the transverse (TD) tensile modulus of the film were measured according to ASTM D882 at a secant modulus of 1% at a test speed of 5 mm / min and a gauge length of 50 mm. The tensile stress at break of the film was measured according to ISO527-3 specimen type 2 at a gauge length of 50 mm and a test speed of 500 mm / min.

[0343] Izod impact strength, notched

[0344] The notched Izod impact strength was measured according to ISO 179 1eA at 23 °C and -20 °C using a molded bar test specimen of 80×10×4 mm 3 which was prepared by compression molding according to ISO 294-1 or ISO 17855-2 using a melt temperature of 200 °C.

[0345] Flexural modulus

[0346] The flexural modulus was determined by three-point bending on a molded specimen of 80×10×4 mm 3 which was prepared by compression molding according to ISO 294-1 or ISO 17855-2 using a melt temperature of 200 °C.

[0347] Strain hardening factor

[0348] The strain hardening factor (SHF) was determined at 180 °C.

[0349] The strain hardening factor is defined as

[0350]

[0351] where

[0352] is the uniaxial tensile viscosity; and

[0353] The Linear Viscoelastic Envelope (LVE) is three times the time-dependent shear viscosity η + (t) in the linear deformation range. The linear viscoelastic envelope in tension was determined based on IRIS Rheo Hub 2008 which requires the calculation of the discrete relaxation time spectrum from the storage modulus data (G'(ω)) and the loss modulus data (G"(ω)). The determination of the linear viscoelastic data G'(ω), G"(ω) was obtained by frequency sweep measurements performed at 180 °C on an Anton Paar MCR 301 coupled with 25 mm parallel plates.

[0354] The basic calculation principle for determining the discrete relaxation spectrum is described in Baumgartel M., Winter H. H., "Determination of the discrete relaxation and retardation time spectra from dynamic mechanical data", Rheol Acta 28: 511 - 519 (1989), the entire content of which is incorporated by reference.

[0355] IRIS Rheo Hub 2008 represents the relaxation time spectrum as the sum of N Maxwell modes

[0356]

[0357] where g i and λ i are material parameters, and G e is the equilibrium modulus.

[0358] The selection of the maximum number of modes N for determining the discrete relaxation spectrum is made by using the option "optimum" in IRIS Rheo Hub. The equilibrium modulus G e is set to zero.

[0359] To obtain a non - linear fit is performed on IRIS Rheo Hub 2008 using the Doi - Edwards model.

[0360] The uniaxial tensile viscosity is obtained from uniaxial tensile flow measurements performed on an Anton Paar MCR 501 coupled with a Sentmanat tensile fixture. The temperature of the uniaxial tensile flow measurement is set to 180 °C, a tensile rate dε / dt of -1 0.3 s -1 to 10 s

[0361] ∈=(I - I0) / I0,

[0362] where I0 is the original length and I is the actual sample fixed length, ranging from 0.3 to 3.0.

[0363] Special attention is paid to the preparation of the sample for tensile flow. The sample is prepared by compression molding at 180 °C followed by controlled cooling to room temperature (without using forced water or air cooling).

[0364] This program allows for obtaining samples with a good shape and no residual stress. Before performing uniaxial tensile measurements, the samples are placed at the test temperature for several minutes to ensure thermal stability (set temperature ±0.1 °C).

[0365] Film shrinkage rate

[0366] The shrinkage rate is determined in oil according to ISO 14616 and / or ISO 11501.

[0367] A 60 mm × 60 mm film sample is placed in oil (polydimethylsiloxane) at 160 °C for 15 seconds. After that, the sample is taken out and conditioned at room temperature for 1 hour. Finally, the shrinkage rate, i.e., the change in dimensions, is measured. The shrinkage rate value is calculated as follows:

[0368] Shrinkage rate = (Lo - Lm) * 100 / Lo

[0369] where Lo is the original length (i.e., 60 mm), and Lm is the length measured after thermal exposure. If the measured value increases (e.g., in the TD direction), the shrinkage rate is negative.

[0370] Optical properties

[0371] Haze is measured according to ASTM D 1003 on a three-layer finished shrink film prepared as described in the example section below.

[0372] Gloss is measured at an angle of 60° according to DIN 67530 / ISO 2813 on a three-layer finished shrink film prepared as described in the example section below. The gloss value is recorded and reported in the form of gloss units (GU).

[0373] Puncture resistance

[0374] The puncture resistance test is carried out on a 60-μm-thick three-layer blown film prepared as described in the example section below according to ASTM D5748. This test method determines the resistance of the film sample to penetration by a probe with a 19-mm-diameter pear-shaped TFE fluorocarbon coating of specific dimensions at a standard low rate and a single test speed (250 mm / min). It is carried out under standard conditions, and the test method applies a biaxial stress load. The film specimen is cut into 150 mm × 150 mm to fit the fixture and conditioned at 23 ± 2 °C and 50 ± 5% relative humidity.

[0375] The puncture energy (J) is the energy used until the probe penetrates the test specimen, both of which are measured using a high-precision 500-N load cell and a crosshead position sensor.

[0376] Sealing initiation temperature (SIT)

[0377] In principle, the heat-sealed portion is formed by bonding two layers of film (polymer) together in such a way that their surfaces are pressed together in close contact and at least partially melted. This test method also covers the evaluation part after the heat-sealing process. The force required to separate the test strip containing the sealed portion of the film is measured using a UTM (also used to identify the failure mode of the specimen). Following ASTM F 2029; ASTM F 88 standards, the preferred film thickness for the test specimen is 30 microns, and the sealed surface is selected. In the case of PE, after sealing, the samples should be conditioned at 23 ± 2 °C and 50 ± 5% relative humidity for at least 24 hours. For testing, at least five specimens should be used for each sealing temperature. The term "sealing initiation temperature" (SIT) is designated as the "heat-sealing initiation temperature at 5 N", and it refers to the temperature at which the sealed portion is formed, which will have a sealing strength of 5 N after cooling. The temperature at which the heat-sealed portion is formed immediately after the sealing operation (sealing time is 1.0 s and sealing pressure is 3 bar for films less than 65 microns thick, and sealing time is 1.5 s for films 65 microns and thicker), and the strength of the heat-sealed portion is measured within a specified time interval (at least 24 hours after the sealing cycle is completed, and after the sealed portion has cooled to ambient temperature and reached maximum strength).

[0378] 2. Materials Used

[0379] FB1350 bimodal ethylene / 1-butene copolymer (MDPE) with a melt flow rate MFR2 of 0.15 g / 10 min,

[0380] MFR5 of 0.60 g / 10 min and a density of 935 kg / m 3 , commercially available from Borouge;

[0381] FB5600 bimodal ethylene / 1-butene copolymer (HDPE) with a melt flow rate MFR2 of 0.7 g / 10 min and a density of 960 kg / m 3 , commercially available from Borouge;

[0382] FT5236 tubular LDPE with a melt flow rate MFR2 of 0.75 g / 10 min and a density of 923 kg / m 3 , commercially available from Borouge; contains a slip additive.

[0383] HP0322N tubular LDPE with a melt flow rate MFR2 of 0.33 g / 10 min and a density of 922 kg / m 3, commercially available from SABIC (Saudi Basic Industries Corporation);

[0384] FK1820 multimodal ethylene / 1-butene / 1-hexene terpolymer with a melt flow rate MFR2 of 1.5 g / 10 min and a density of 918 kg / m 3 , commercially available from Borouge;

[0385] FK2715 multimodal ethylene / 1-butene / 1-hexene terpolymer with a melt flow rate MFR2 of 1.3 g / 10 min and a density of 927 kg / m 3 , commercially available from Borouge;

[0386] 3505MC Enable 3505MC; metallocene-catalyzed ethylene / 1-hexene copolymer with a melt flow rate MFR2 of 0.5 g / 10 min and a density of 935 kg / m 3 , commercially available from ExxonMobil;

[0387] 1327MD Exceed 1327MD; metallocene-catalyzed ethylene / 1-hexene copolymer with a melt flow rate MFR2 of 1.3 g / 10 min and a density of 927 kg / m 3 , commercially available from ExxonMobil;

[0388] rLDPE1 PCR-LDPE(ML)-A; post-consumer waste LDPE (total content of LDPE + LLDPE > 80 wt%) with a melt flow rate MFR2 of 1.1 g / 10 min and a density of 925 kg / m 3 , commercially available from Suzhou Jinhui Technology;

[0389] rLDPE2 post-consumer waste LDPE with a melt flow rate MFR2 of 0.8 g / 10 min and a density of 923

[0390] kg / m 3 , commercially available from Plaspulp.

[0391] 3. Properties of the materials

[0392] rLDPE

[0393] The properties of rLDPE1 and rLDPE2 were measured on molded specimens and are listed in Table 1 below.

[0394] Table 1: Properties of rLDPE1 and rLDPE2

[0395] Properties rLDPE1 rLDPE2 Tensile modulus 309 MPa 319 MPa Yield tensile stress 10.6 MPa 10.7 MPa Elongation at break 808％ 475％ Flexural modulus 379 MPa 317 MPa Izod impact strength, notched, 23 °C <![CDATA[78.7kJ / m 2 > <![CDATA[60.6kJ / m 2 > Izod impact strength, notched, -20 °C <![CDATA[11.3kJ / m 2 > <![CDATA[8.8kJ / m 2 >

[0396] Strain hardening factor

[0397] The strain hardening factors (SHF) of FT5230 (original LDPE), rLDPE1, and rLDPE2 were measured at a strain rate of 3.0 s -1 at 180 °C and a Hencky strain of 2.5. The results are shown in Table 2 below.

[0398] Table 2: Strain hardening factor

[0399] Material SHF FT5236 (original LDPE) 2.90 rLDPE1 2.02 rLDPE2 3.14

[0400] 4. Collation shrink film

[0401] These films were produced on an industrial-scale three-layer extrusion blow molding film production line (Polyrema) using three extruders (the main zone temperature of the extruders was set at 180 to 220 °C, the die diameter was 180 mm, the blow-up ratio (BUR) was 1:3, the die gap was 1.8 mm, with internal bubble cooling). The blow molding films made of polyethylene blends are described herein for each film layer. Any polyethylene blend used in the film layers described above can be produced by any suitable conventional multi-layer film extrusion production line, preferably at a temperature of 150 to 230 °C, more preferably at a temperature of 160 to 225 °C. Conventional blow molding film production techniques for this purpose are, in principle, known and available to those skilled in the art. Generally, each film layer is co-extruded at a temperature in the range of 160 to 225 °C, the die temperature is in the range of 205 to 220 °C, and is cooled by blowing air at a temperature of 12 to 16 °C to provide a frost line height that is 1 to 2 times the die diameter. The blow molding films were produced on Polyrema (a Reifenhauser blow molding film production line with an internal bubble cooling system) at a production rate of 150 kg / h.

[0402] In the first method, ABC film layers of Comparative Examples CE-1 and CE-2 and Example IE-1 and IE-2 of the present invention with a total thickness of 60 to 70 μm were prepared, and the thickness distribution of the ABC film was 20% / 60% / 20%. In the first method, the total rLDPE content of the ABC film was in the range of 15 to 20% by weight. The thickness and composition of the sealing layer (C) were the same as those of the outer layer (A). The composition of the ABC film layers of the first method is shown in Table 3 below.

[0403] In the second method, comparative example CE-3 and ABC film layers of examples IE-3, IE-4 and IE-5 of the present invention with a total thickness of 60 to 70 μm were prepared, and the thickness distribution of the ABC film was 25% / 50% / 25%. In the second method, the total rLDPE content of the ABC film was in the range of 35 to 40% by weight. The thickness and composition of the sealing layer (C) were the same as those of the outer layer (A). The composition of the ABC film layer of the second method is shown in Table 4 below.

[0404] Table 3: Collation shrink film (ABC film layer) of the first method

[0405]

[0406] Table 4: Collation shrink film (ABC film layer) of the second method

[0407]

[0408] The longitudinal (MD) shrinkage rate and transverse (TD) shrinkage rate of the films of examples IE-1, IE-2, CE-1 and CE-2 were measured and are shown in Figure 1 as follows.

[0409] The films of IE-1 and IE-2 showed MD shrinkage rates of 73% and 74% of the film, which were slightly lower than the MD shrinkage rates of the films of CE-1 and CE-2, but were all within a comparable range (between 72% and 78%).

[0410] The films of IE-1 and IE-2 showed TD shrinkage rates of 10% and 11%, which were comparable to the TD shrinkage rates of CE-1 and CE-2.

[0411] The transverse (TD) shrinkage rates of the films of examples IE-3, IE-4, IE-5 and CE-3 were measured and are shown in Figure 2 as follows. All of these film examples of IE-3, IE-4, IE-5 and CE-3 showed MD shrinkage rates of the film of 75 to 77%, which were comparable to each other.

[0412] The films of IE-3, IE-4 and IE-5 showed TD shrinkage rates of the film of 13% to 16%, while the film of CE-3 showed a TD shrinkage rate of 9%.

[0413] The optical properties of examples IE-3, IE-4, IE-5 and CE-3 were measured and are shown in Figure 3 (haze) and Figure 4 (gloss at 60°) as follows.

[0414] The films of IE-3, IE-4, and IE-5 all showed a haze of 12.0% to 15.5%, while the film of CE-3 showed a haze of 19.7%.

[0415] The films of IE-3, IE-4, and IE-5 all showed a gloss at 60° of 79 to 98 GU, while the film of CE-3 showed a gloss at 60° of 86 GU.

[0416] The tensile properties of Examples IE-3, IE-4, IE-5, and CE-3 were measured and are shown in Figure 5 hereinbelow.

[0417] The films of IE-3, IE-4, and IE-5 showed a longitudinal (MD) tensile modulus of 257 to 295 MPa, while the film of CE-3 showed a longitudinal (MD) tensile modulus of 302 MPa.

[0418] The films of IE-3, IE-4, and IE-5 showed a transverse (TD) tensile modulus of 289 to 311 MPa, while the film of CE-3 showed a transverse (TD) tensile modulus of 355 MPa.

[0419] The films of IE-3, IE-4, and IE-5 showed a longitudinal (MD) breaking tensile stress of 14.5 to 18.2 MPa, while the film of CE-3 showed a longitudinal (MD) breaking tensile stress of 15.8 MPa.

[0420] The films of IE-3, IE-4, and IE-5 showed a transverse (TD) breaking tensile stress of 21.0 to 23.1 MPa, while the film of CE-3 showed a transverse (TD) breaking tensile strain of 26.3 MPa.

[0421] The puncture energy and SIT of Examples IE-3, IE-4, IE-5, and CE-3 were measured and are shown in Figure 6 hereinbelow.

[0422] The films of IE-3, IE-4, and IE-5 showed a puncture energy of 1.1 to 1.3 J, while the film of CE-3 showed a puncture energy of 1.2 J.

[0423] The films of IE-3, IE-4, and IE-5 showed a SIT of 108.0 to 111.1 °C, while the film of CE-3 showed a SIT of 110.6 °C.

[0424] The films according to the invention showed comparable TD shrinkage rates, comparable mechanical properties, comparable puncture energies, and comparable SITs that are generally acceptable on the market, while the films according to the invention showed improved haze and comparable gloss.

[0425] Thus, the film according to the invention shows a good balance of shrinkage rate, mechanical properties, puncture resistance, sealing properties and optical properties and, surprisingly, is not impaired by the presence of up to 40 wt% recycled LDPE.

Claims

1. A multi-layered finishing shrink film comprising at least the following layers: (A) A layer comprising the following components: (A1) A multimodal copolymer of ethylene and at least one comonomer selected from α-olefins having 4 to 10 carbon atoms, the multimodal polymer of ethylene having a density of 920 to 940 kg / m 3 , preferably 922 to 937 kg / m 3 , most preferably 925 to 935 kg / m 3 as determined according to ISO 1183 and a melt flow rate MFR2 of 0.5 to 2.0 g / 10 min, preferably 0.7 to 1.8 g / 10 min, most preferably 1.0 to 1.6 g / 10 min as determined according to ISO 1133 at a temperature of 190 °C and a load of 2.16 kg, and (A2) LDPE; and (B) A layer comprising the following components: (B1) Recycled LDPE; A copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, the copolymer of ethylene having a density of 930 to 970 kg / m 3 , preferably 932 to 965 kg / m 3 , most preferably 933 to 963 kg / m 3 determined according to ISO 1183 and a melt flow rate of 0.10 to 2.0 g / 10 min, preferably 0.11 to 1.5 g / 10 min, Most preferably, the melt flow rate MFR2 measured according to ISO 1133 at a temperature of 190 °C and a load of 2.16 kg is from 0.12 to 1.0 g / 10 min.

2. The multi-layered finishing shrink film according to claim 1, wherein the multi-layer film comprises 3 layers, preferably consists of 3 layers, preferably wherein layer (B) is the core layer and layer (A) is the outer layer adhesively contacting the core layer (B), more preferably wherein layer (B) is the core layer sandwiched between two layers (A), and both of the two layers (A) are preferably adhesively contacting each surface of the core layer (B).

3. The multi-layered finishing shrink film according to claim 1 or 2, wherein The multimodal copolymer of ethylene (A1) is present in layer (A) in an amount of 15 to 90% by weight, preferably 18 to 85% by weight, most preferably 20 to 82% by weight, and The LDPE (A2) is present in layer (A) in an amount of 10 to 85% by weight, preferably 15 to 82% by weight, most preferably 18 to 80% by weight, both based on the total weight of layer (A); and The recycled LDPE (B1) is present in layer (B) in an amount of 20 to 85% by weight, preferably 25 to 80% by weight, most preferably 27 to 77% by weight, and The copolymer of ethylene (B2) is present in layer (B) in an amount of 15 to 80% by weight, preferably 20 to 75% by weight, most preferably 23 to 73% by weight, both based on the total weight of layer (B).

4. The multi-layered finishing shrink film according to any one of claims 1 to 3, wherein the thickness of one layer (B) in the multi-layered finishing shrink film is in the range of 40 to 70%, preferably in the range of 44 to 66%, most preferably in the range of 48 to 62%, and the thickness of one layer (A) in the multi-layered finishing shrink film is in the range of 10 to 30%, preferably in the range of 15 to 28%, most preferably in the range of 19 to 26%, both based on the total thickness of the multi-layered finishing shrink film.

5. The multi-layered finishing shrink film according to any one of claims 1 to 4, wherein the LDPE (A2) comprises virgin LDPE, recycled LDPE or a mixture of virgin LDPE and recycled LDPE, and the weight ratio of virgin LDPE to recycled LDPE in the mixture is preferably in the range of 5:1 to 1:2, more preferably in the range of 4:1 to 1:1, most preferably in the range of 3:1 to 2:

1.

6. The multi-layered finishing shrink film according to any one of claims 1 to 5, wherein the total amount of recycled LDPE in the multi-layered finishing shrink film is 10 to 55% by weight, preferably 12 to 53% by weight, most preferably 15 to 50% by weight, based on the total weight of the multi-layered finishing shrink film.

7. The multilayer shrink film for collation according to any one of claims 1 to 6, wherein the recycled LDPE (B1) is derived from post-consumer waste or post-industrial waste, preferably from post-consumer waste.

8. The multilayer shrink film for collation according to any one of claims 1 to 7, wherein the recycled LDPE (B1) has one or more of the following properties, or has all of the following properties: · 915 to 935 kg / m 3 , preferably 917 to 932 kg / m 3 , most preferably 920 to 930 kg / m 3 density measured according to ISO 1183; · A melt flow rate MFR2 measured according to ISO 1133 at a temperature of 190 °C and a load of 2.16 kg of 0.1 to 2.0 g / 10 min, preferably 0.3 to 1.7 g / 10 min, most preferably 0.5 to 1.5 g / 10 min; · A tensile modulus measured according to ISO 527-2 / 1A of 200 to 450 MPa, preferably 225 to 425 MPa, most preferably 250 to 400 MPa; · A yield tensile stress measured according to ISO 527-2 / 1A of 6.0 to 15.0 MPa, preferably 7.5 to 12.5 MPa, most preferably 9.0 to 11.5 MPa; · A tensile strain at break measured according to ISO 527-2 / 1A of 350 to 1200%, preferably 375 to 1100%, most preferably 400 to 1000%; · A flexural modulus measured according to ISO 178 of 200 to 500 MPa, preferably 225 to 475 MPa, most preferably 250 to 450 MPa; · 40 to 120 kJ / m 2 , preferably 45 to 110 kJ / m 2 , most preferably 50 to 100 kJ / m 2 of the notched Izod impact strength at 23 °C determined according to ISO 179 1eA; · 5.0 to 20.0 kJ / m 2 , preferably 6.0 to 18.0 kJ / m 2 , most preferably 7.0 to 16.0 kJ / m 2 notched Izod impact strength at -20 °C determined according to ISO 1791eA; and / or · 1.5 to 5.0, preferably 1.8 to 4.5, strain hardening factor measured at a strain rate of 3.0 s-1 and a Hencky strain of 2.5 at 180 °C. -1 ​ 9. The multilayer shrink film for finishing according to any one of claims 1 to 8, wherein the copolymer (B2) of ethylene is a medium-density copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, and the medium-density copolymer has a density of 930 to 945 kg / m 3 , preferably 932 to 942 kg / m 3 , most preferably 933 to 940 kg / m 3 determined according to ISO 1183 and a melt flow rate MFR2 of 0.10 to 0.50 g / 10 min, preferably 0.10 to 0.40 g / 10 min, most preferably 0.12 to 0.30 g / 10 min determined according to ISO 1133 at a temperature of 190 °C and a load of 2.16 kg, and / or the copolymer (B2) of ethylene is a high-density copolymer of ethylene and a comonomer selected from α-olefins having 4 to 10 carbon atoms, and the high-density copolymer has a density of 950 to 970 kg / m 3 , preferably 952 to 965 kg / m 3 , most preferably 955 to 963 kg / m 3 determined according to ISO 1183 and a melt flow rate MFR2 of 0.30 to 2.0 g / 10 min, preferably 0.40 to 1.5 g / 10 min, most preferably 0.50 to 1.0 g / 10 min determined according to ISO 1133 at a temperature of 190 °C and a load of 2.16 kg, or the copolymer (B2) of ethylene is a mixture of the medium-density ethylene copolymer and the high-density ethylene copolymer, and / or wherein the copolymer (B2) of ethylene is a copolymer of ethylene and 1-butene comonomer units or a copolymer of ethylene and 1-hexene comonomer units, and the 1-butene comonomer units or the 1-hexene comonomer units are the only comonomer units present in the copolymer (B2) of ethylene.

10. The multilayer shrink film for collation according to any one of claims 1 to 9, wherein the multimodal copolymer of ethylene (A1) is a terpolymer of ethylene and two different comonomers selected from α-olefins having 4 to 10 carbon atoms, preferably the multimodal copolymer of ethylene (A1) is a terpolymer of ethylene, 1-butene comonomer units and 1-hexene comonomer units, wherein the 1-butene comonomer units and the 1-hexene comonomer units are the only comonomer units present in the copolymer (A1) of ethylene, and more preferably the multimodal copolymer of ethylene (A1) comprises a copolymer of ethylene and 1-butene comonomer units and a copolymer of ethylene and 1-hexene comonomer units.

11. The multi-layer oriented shrink film according to any one of claims 1 to 10, wherein the LDPE (A2) has a density of 915 to 935 kg / m 3 , preferably 917 to 932 kg / m 3 , most preferably 920 to 930 kg / m 3 as determined according to ISO 1183 and a melt flow rate MFR2 of 0.1 to 2.0 g / 10 min, preferably 0.2 to 1.5 g / 10 min, most preferably 0.3 to 1.2 g / 10 min as determined according to ISO 1133 at a temperature of 190 °C and a load of 2.16 kg.

12. Multilayer sorting and shrink film according to any one of claims 1 to 11, wherein layer (B) further comprises a multimodal polymer (B3) of ethylene and at least two different comonomers selected from α-olefins having 4 to 10 carbon atoms, the multimodal polymer of ethylene having a density of 910 to 930 kg / m 3 , preferably 912 to 927 kg / m 3 , most preferably 915 to 925 kg / m 3 determined according to ISO 1183 and a melt flow rate MFR2 of 0.5 to 2.5 g / 10 min, preferably 1.0 to 2.0 g / 10 min, most preferably 1.2 to 1.8 g / 10 min determined according to ISO 1133 at a temperature of 190 °C and a load of 2.16 kg.

13. The multilayer shrink film for collation according to any one of claims 1 to 12, which has one or more of the following properties, or has all of the following properties: · A longitudinal shrinkage rate of 60 to 85%, preferably 65 to 82%, most preferably 70 to 80% measured according to ISO 14616 and / or ISO 11501; · A transverse shrinkage rate of 5 to 25%, preferably 7 to 22%, most preferably 9 to 20% measured according to ISO 14616 and / or ISO 11501; · A haze of 5.0 to 19.0%, preferably 7.0 to 18.0%, most preferably 8.0 to 17.0% measured according to ASTM D 1003; ·Gloss at 60° measured according to DIN 67530 / ISO 2813 of 70 to 130, preferably 73 to 120, most preferably 75 to 110; ·Longitudinal tensile modulus measured according to ASTM D882 of 225 to 600 MPa, preferably 240 to 550 MPa, most preferably 250 to 500 MPa; ·Transverse tensile modulus measured according to ASTM D882 of 250 to 650 MPa, preferably 265 to 600 MPa, most preferably 275 to 550 MPa; ·Longitudinal fracture tensile stress measured according to ISO 527-3 of 12.0 to 40.0 MPa, preferably 13.0 to 38.0 MPa, most preferably 14.0 to 36.0 MPa; ·Transverse fracture tensile stress measured according to ISO 527-3 of 15.0 to 40.0 MPa, preferably 18.0 to 36.0 MPa, most preferably 20.0 to 32.0 MPa; ·Puncture energy measured according to ASTM D 5748 of 0.8 to 3.0 J, preferably 0.9 to 2.5 J, most preferably 1.0 to 2.0 J; and / or ·Sealing start temperature measured according to ASTM F 2029 and ASTM F88 of 100 to 125 °C, preferably 103 to 120 °C, most preferably 105 to 115 °C.

14. A method for manufacturing a multilayer oriented shrink film according to any one of claims 1 to 13, characterized in that, The film is manufactured by a one-step blown film coextrusion process. Use of the multilayer finishing shrink film according to any one of claims 1 to 14 for secondary packaging, preferably for bottles and cans, more preferably for bottles and cans in the fields of household products, food products, health care products and beverage products.

Images