Bags for bulk goods
By adopting a multi-layer film structure and specific polymer composition method, the problems of instability of membrane bubbles and insufficient mechanical characteristics in high-speed production of plastic bags are solved, and the effects of high membrane bubble stability and high impact strength are achieved.
Patent Information
- Application Number
- CN202080070839.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2019-10-09
- Filing Date
- 2020-09-21
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2040-09-21
AI Technical Summary
The film bubbles of existing plastic bags are unstable during high-speed production, resulting in interruption of film production and difficulty in withstanding external impact during stacking and transportation, resulting in insufficient mechanical characteristics.
A multi-layer film structure is adopted, including a specific composition of the first outer layer, a core layer and a second outer layer, polymer (A) and polymer (B), ensuring the stability of the membrane bubble and the high impact strength of the dart.
It realizes stable production of films at high speeds, and improves the mechanical strength of the bags, which can effectively withstand external force impacts during transportation and stacking.
Smart Images
Figure BDA0003586120730000101 
Figure BDA0003586120730000111
Abstract
Description
Technical Field
[0001] The present invention relates to bags for containing bulk goods. In particular, the present invention relates to bags produced from polyethylene film. Background Art
[0002] In the field of bulk goods packaging, especially the packaging of powder or granular bulk goods, a typical type of packaging is several kilograms of bulk goods, such as 5-50 kg of goods. Such packaging usually uses plastic bags. For example, each of such plastic bags can hold 10, 20, 25 or 50 kg of bulk goods. Such bags are also called heavy-duty bags.
[0003] In logistics operations involving the use of such bags, a large number of such bags are stacked on a pallet. Such a pallet can accommodate, for example, 20-100 bags. Such bags are usually placed on a flat pallet so that they lean against the side walls. Many bags, such as 4 or 5 bags, are placed on the pallet to form a layer, on which a larger number of bags are placed to form another layer, and this operation is repeated, so that a fully loaded pallet can be loaded with a considerable number of layers, such as 5-25 layers, each layer having a plurality of bags lying flat on their side walls.
[0004] These bags are stacked on a pallet and represent a considerable amount of weight. In order for the bags to maintain their position on the pallet, the plastic material from which the bags are made needs to meet certain specifications.
[0005] According to the present invention, bags for bulk cargo can be produced by blown film extrusion. In the continuous process of blown film extrusion, the polymer material is converted into a molten stream by a melt extruder, the stream is extruded through a typical annular die, and a tubular film is formed by an air flow (such as an air flow), which forms a solidified plastic film after air cooling. The annular die can be provided with resin by multiple melt extruders, so that a multilayer film, such as a 3-layer film or a 5-layer film, can be formed. Subsequently, the film is rolled up. The tubular film formed between the film mold and the winding section is called a film bubble. The size of the air flow usually allows the material that leaves the annular die in a liquid state at this stage to expand before solidification. The ratio between the radius of the annular die and the radius of the tubular film formed in this way is called the blow-up ratio.
[0006] In order to provide optimal process efficiency, the production of blown film is usually carried out at the highest possible speed allowed by the equipment and the material to be converted. One of the limiting factors is the stability of the tubular film formed at the bubble stage. High processing speeds may cause instabilities such as vibrations, which may cause the bubble to collapse and thus interrupt the continuous production of film.
[0007] It will be appreciated that good bubble stability is an essential factor in order to achieve maximum economy of process and materials. Bubble stability can be influenced by the choice of polymer material used to form the film. Thus, in accordance with the present invention, when producing bags for bulk goods, materials are required that help provide good bubble stability during the film preparation process.
[0008] In addition, the bag itself needs to have mechanical properties suitable for its purpose, i.e., to allow bulk goods to be stored for a certain period of time under typical conditions. For example, such a bulk bag may contain a certain amount of bulk products, such as polymer pellets, inorganic powder materials, powdered foods such as flour, and similar powdered or granular products. Typically, a plurality of such bags are stacked together on a pallet and may be subject to certain external forces, such as blunt or sharp impacts, during storage and transportation. Therefore, the film made of the bag needs to be able to withstand certain impact forces, which is verified by the dart impact strength measured according to ASTM D1709 method A. Summary of the invention
[0009] Therefore, it is necessary to provide a bag having the desired high dart impact strength which can be produced by blown film extrusion at high speed and high bubble stability. According to the present invention, there is now provided a bag for storing bulk goods, wherein the bag comprises a multilayer film, the multilayer film comprising:
[0010] (a) a first outer layer;
[0011] (c) a core layer; and
[0012] (e) a second outer layer;
[0013] wherein layers (a), (c) and (e) are placed relative to each other in this order;
[0014] The multilayer film comprises:
[0015] ≥50.0 wt%, preferably ≥50.0 and ≤80.0 wt%, of polymer (A), relative to the total weight of the multilayer film, said polymer (A) comprising a portion derived from ethylene and a portion derived from 1-hexene, wherein said polymer (A) has:
[0016] (i) Measured according to ASTM D792 (2008): ≥910 and ≤930 kg / m 3 density;
[0017] (ii) a melt mass flow rate of ≥0.5 and ≤5.0 g / 10 min at a temperature of 190° C. and a load of 2.16 kg as measured according to ASTM D1238 (2013);
[0018] (iii) ≤ 6.0 wt % relative to the total weight of the polymer in a fraction eluting in analytical temperature rising elution fractionation (a-TREF) at a temperature of ≤ 30.0°C; and
[0019] (iv) ≥ 20.0 wt% of the fraction eluting in a-TREF at a temperature > 94.0°C, relative to the total weight of the polymer; and
[0020] ≥20.0 and ≤50.0 wt%, preferably ≥20.0 and ≤40.0 wt%, of polymer (B), relative to the total weight of the multilayer film, the polymer (B) comprising a portion derived from ethylene and a portion derived from 1-butene, 1-hexene or 1-octene, preferably containing ≥0.5 and ≤5.0 wt% of a portion derived from 1-butene, 1-hexene or 1-octene, wherein the polymer (B) has:
[0021] (v) ≥945 and ≤965 kg / m2 measured according to ASTM D792 (2008) 3 density;
[0022] (vi) a melt mass flow rate of ≥0.01 and ≤1.00, preferably ≥0.01 and ≤0.50, preferably ≥0.01 and ≤0.10 g / 10 min, measured according to ASTM D1238 (2013) at a temperature of 190° C. and a load of 2.16 kg; and
[0023] (vii) a melt mass flow rate of ≥5.0 and ≤50.0, preferably ≥5.0 and ≤25.0 g / 10 min, measured according to ASTM D1238 (2013) at a temperature of 190° C. and a load of 21.6 kg.
[0024] Such bags can be produced by blown film extrusion at high speeds and high bubble stability, and have the desired high dart impact strength.
[0025] For example, the polymer (A) may have:
[0026] · fraction (iii) eluting in a-TREF at a temperature ≤ 30.0°C is ≥ 1.0 and ≤ 6.0 wt% relative to the total weight of the polymer; and / or
[0027] The fraction (iv) eluting in a-TREF at a temperature > 94.0°C is ≥ 20.0 and ≤ 40.0 wt% relative to the total weight of the polymer; and / or
[0028] • Fractions eluting in a-TREF at temperatures > 30.0°C and ≤ 94.0°C are ≥ 54.0 and ≤ 79.0 wt%.
[0029] According to the present invention, analytical temperature rising elution fractionation (also referred to as a-TREF) can be performed using a Polymer CharCrystaf-TREF 300 using a solution containing 4 mg / ml of sample prepared in 1,2-dichlorobenzene, which is stabilized at a temperature of 150°C for 1 hour with 1 g / l Topanol CA (1,1,3-tris(3-tert-butyl-4-hydroxy-6-methylphenyl)butane) and 1 g / l Irgafos 168 (tris(2,4-di-tert-butylphenyl)phosphite). Prior to analysis, the solution can be stabilized at 95°C for an additional 45 minutes with continuous stirring at 200 rpm. For analysis, the solution is crystallized by cooling from 95°C to 30°C with a cooling rate of 0.1°C / min. Elution is performed from 30°C to 140°C with a heating rate of 1°C / min. The equipment is cleaned at 150°C.
[0030] Specifically, a-TREF can be implemented using Polymer Char Crystaf-TREF 300 using a solution containing 4 mg / ml polymer in 1,2-dichlorobenzene, wherein the solution is stabilized with 1 g / l 1,1,3-tris(3-tert-butyl-4-hydroxy-6-methylphenyl)butane and 1 g / l tris(2,4-di-tert-butylphenyl)phosphite at a temperature of 150°C for 1 hour, and optionally stabilized at 95°C for another 45 minutes under continuous stirring at 200 rpm, wherein before analysis, the solution is crystallized by cooling from 95°C to 30°C using a cooling rate of 0.1°C / min, and elution is performed from 30°C to 140°C using a heating rate of 1°C / min, and wherein the equipment is cleaned at 150°C.
[0031] For example, the density of the polymer (A) may be ≥910 and ≤925 kg / m 3 , preferably ≥915 and ≤925kg / m 3 , more preferably ≥915 and ≤920kg / m 3 .
[0032] For example, measured according to ASTM D1238 (2013) at a temperature of 190° C. and a load of 2.16 kg, the melt mass flow rate of the polymer (A) may be ≥0.5 and ≤4.0 g / 10 min, preferably ≥0.5 and ≤3.0 g / 10 min, and more preferably ≥0.5 and ≤2.0 g / 10 min.
[0033] For example, the polymer (A) may contain ≤5.0 wt%, preferably ≤4.0, more preferably ≤3.0, of a fraction eluted in analytical temperature rising elution fractionation (a-TREF) at ≤30.0° C., relative to the total weight of the polymer (A). This fraction content means that a relatively small amount of amorphous substances is present in the polymer (A).
[0034] For example, polymer (A) may comprise ≥20.0 wt%, preferably ≥20.0 and ≤40.0 wt%, more preferably ≥22.5 and ≤30.0 wt%, even more preferably ≥25.0 and ≤30.0 wt% of a fraction eluting in a-TREF at >94.0° C., relative to the total weight of polymer (A). This fraction content means that a relatively large amount of linear polymer chains are present in polymer (A).
[0035] For example, polymer (A) may comprise ≥ 2.5 and ≤ 20.0 wt%, preferably ≥ 5.0 and ≤ 15.0 wt%, more preferably ≥ 5.0 and ≤ 10.0 wt% of moieties derived from 1-hexene, relative to the total weight of polymer (A).
[0036] The amount of the fraction derived from 1-hexene in polymer (A) and the amount of the fraction derived from 1-butene, 1-hexene or 1-octene in polymer (B) can be measured, for example, on a Bruker Avance 500 spectrophotometer equipped with a cryogenically cooled probe operated at 125° C. 13 C NMR was measured, where the sample was dissolved in C2D2Cl4 containing DBPC as a stabilizer at 130°C.
[0037] The weight average molecular weight M of the polymer (A) w For example, it may be ≥50 and ≤500 kg / mol, preferably ≥75 and ≤300, more preferably ≥100 and ≤250. The number average molecular weight M of polymer (A) n For example, it may be ≥10 and ≤100 kg / mol, preferably ≥20 and ≤75, more preferably ≥25 and ≤50. The molecular weight distribution MWD of polymer (A) is given by w / M n The ratio may be ≥1.0 and ≤10.0, preferably ≥2.0 and ≤7.5, more preferably ≥3.0 and ≤5.0.
[0038] In the context of the present invention, M n 、M w and M z All are expressed in kg / mol and measured according to ASTM D6474 (2012).
[0039] The density of polymer (B) can be, for example, ≥945 and ≤965 kg / m, as measured according to ASTM D792 (2008). 3 , preferably ≥945 and ≤960kg / m 3 , more preferably ≥950 and ≤960kg / m 3 , or ≥955 and ≤965kg / m 3The melt mass flow rate of polymer (B) can be, for example, ≥5.0 and ≤25.0 g / 10 min, preferably ≥5.0 and ≤20.0 g / 10 min, more preferably ≥7.5 and ≤15.0 g / 10 min, measured according to ASTM D1238 (2013) at a temperature of 190° C. and a load of 21.6 kg.
[0040] It is preferred that the multilayer film used in the bag of the present invention comprises ≤3.0 wt% low density polyethylene (LDPE), preferably ≤2.0 wt% or ≤1.0 wt%, relative to the total weight of the multilayer film, wherein the multilayer film preferably does not contain LDPE. Using LDPE in such a small amount, or even without LDPE, is understood to help improve the dart impact strength of the bag.
[0041] In those embodiments of the present invention wherein the bag comprises a multilayer film, wherein the multilayer film comprises or consists of layers (a), (c) and (e), preferably each layer (a) and layer (e) comprises ≥75.0 wt%, preferably ≥80.0 and ≤95.0 wt% of polymer (A), and ≥4.0, or ≥5.0, preferably ≥5.0 and ≤20.0 wt% of polymer (B), wherein the wt% of each polymer (A) and (B) is expressed relative to the total weight of each layer (a) or (e), respectively, and wherein the composition of layer (a) and layer (e) is preferably the same.
[0042] In those embodiments of the bag of the present invention comprising a multilayer film, wherein the multilayer film comprises or consists of layers (a), (c) and (e), it is preferred that layer (c) comprises ≥30.0 and ≤70.0 wt%, preferably ≥40.0 and ≤60.0 wt% of polymer (A), and ≥30.0 and ≤70.0 wt%, preferably ≥40.0 and ≤60.0 wt% of polymer (B), relative to the total weight of layer (c).
[0043] In certain embodiments of the present invention, the multilayer film consists of layers (a), (c) and (e).
[0044] In those embodiments of the invention wherein the bag comprises a multilayer film, wherein the multilayer film comprises or consists of layers (a), (c) and (e), preferably:
[0045] The weight of layer (a) is ≥ 10.0 and ≤ 40.0 wt%, preferably ≥ 20.0 and ≤ 30.0 wt%; and / or
[0046] The weight of layer (c) is ≥ 20.0 and ≤ 80.0 wt%, preferably ≥ 40.0 and ≤ 60.0 wt%; and / or
[0047] The weight of layer (e) is ≥10.0 and ≤40.0 wt%, preferably ≥20.0 and ≤30.0 wt%;
[0048] The weight of each layer (a), (c) and (e) is expressed relative to the total weight of the multilayer film.
[0049] In those embodiments of the invention wherein the bag comprises a multilayer film, wherein the multilayer film comprises or consists of layers (a), (c) and (e), preferably:
[0050] The thickness of layer (a) is ≥10.0 and ≤40.0 μm, preferably ≥20.0 and ≤30.0 μm; and / or
[0051] The thickness of layer (c) is ≥20.0 and ≤80.0 μm, preferably ≥40.0 and ≤60.0 μm; and / or
[0052] The thickness of layer (e) is ≥10.0 and ≤40.0 μm, preferably ≥20.0 and ≤30.0 μm.
[0053] Alternatively, the present invention also relates to some embodiments wherein the multilayer film comprises, in addition to layers (a), (c) and (e):
[0054] (b) a first intermediate layer; and
[0055] (d) a second intermediate layer;
[0056] wherein layer (b) is located between layer (a) and layer (c), and layer (d) is located between layer (c) and layer (e).
[0057] In those embodiments of the bag of the present invention comprising a multilayer film, wherein the multilayer film comprises or consists of layers (a), (b), (c), (d) and (e), preferably each layer (b) and layer (d) contains ≥75.0 wt%, preferably ≥85.0 and ≤95.0 wt% of polymer (A), or consists of polymer (A), wherein the wt% of polymer (A) is expressed relative to the total weight of each layer (b) or (d), respectively, wherein the composition of layer (b) and layer (d) is preferably the same.
[0058] In those embodiments of the present invention wherein the bag comprises a multilayer film, wherein the multilayer film comprises or consists of layers (a), (b), (c), (d) and (e), preferably each layer (a) and layer (e) comprises ≥75.0 wt%, preferably ≥80.0 and ≤95.0 wt% of polymer (A), and ≥4.0, or ≥5.0, preferably ≥5.0 and ≤20.0 wt% of polymer (B), wherein the wt% of each polymer (A) and (B) is expressed relative to the total weight of each layer (a) or (e), respectively, and wherein the composition of layer (a) and layer (e) is preferably the same.
[0059] In those embodiments of the bag of the present invention comprising a multilayer film, wherein the multilayer film comprises or consists of layers (a), (b), (c), (d) and (e), it is preferred that layer (c) contains ≥75.0 wt%, preferably ≥85.0 and ≤99.0 wt% of polymer (A), or consists of polymer (A), wherein the wt% of polymer (A) is expressed relative to the total weight of layer (c).
[0060] In certain embodiments of the present invention, the bag comprises a multilayer film consisting of layers (a), (b), (c), (d) and (e).
[0061] In those embodiments of the invention wherein the bag comprises a multilayer film, wherein the multilayer film comprises or consists of layers (a), (b), (c), (d) and (e), preferably:
[0062] The weight of layer (a) is ≥ 10.0 and ≤ 20.0 wt%, preferably ≥ 12.5 and ≤ 17.5 wt%; and / or
[0063] The weight of layer (b) is ≥ 10.0 and ≤ 20.0 wt%, preferably ≥ 12.5 and ≤ 17.5 wt%; and / or
[0064] The weight of layer (c) is ≥ 20.0 and ≤ 60.0 wt%, preferably ≥ 30.0 and ≤ 50.0 wt%; and / or
[0065] The weight of layer (d) is ≥ 10.0 and ≤ 20.0 wt%, preferably ≥ 12.5 and ≤ 17.5 wt%; and / or
[0066] The weight of layer (e) is ≥10.0 and ≤20.0 wt%, preferably ≥12.5 and ≤17.5 wt%;
[0067] The wt % of each layer (a), (b), (c), (d) and (e) is expressed relative to the total weight of the multilayer film.
[0068] In those embodiments of the invention wherein the bag comprises a multilayer film, wherein the multilayer film comprises or consists of layers (a), (b), (c), (d) and (e), preferably:
[0069] The thickness of layer (a) is ≥10.0 and ≤20.0 μm, preferably ≥12.5 and ≤17.5 μm; and / or
[0070] The thickness of layer (b) is ≥10.0 and ≤20.0 μm, preferably ≥12.5 and ≤17.5 μm; and / or
[0071] The thickness of layer (c) is ≥20.0 and ≤60.0 μm, preferably ≥30.0 and ≤50.0 μm; and / or
[0072] The thickness of layer (d) is ≥10.0 and ≤20.0 μm, preferably ≥12.5 and ≤17.5 μm; and / or
[0073] The thickness of layer (e) is ≥10.0 and ≤20.0 μm, preferably ≥12.5 and ≤17.5 μm.
[0074] The thickness of the multilayer film can be, for example, ≥70 and ≤150 μm, preferably ≥80 and ≤120 μm.
[0075] The present invention is now described by way of the following non-limiting examples.
[0076] The following materials are used in the examples:
[0077] Polymer (A) SABIC Supeer 7118NE Polymer (B) SABIC HDPE F00952J LDPE SABIC LDPE 2100N0 TiO2 Masterbatch of 70wt% titanium dioxide in 30wt% LDPE carrier resin
[0078] Nature of the material:
[0079] Polymer (A): SABIC Supeer 7118NE
[0080] polymer SABIC Supeer 7118NE MFR2 0.95 density 919 Ethylene unit content 91.1 Comonomer unit content 8.9 Comonomer type C6 Comonomer branch content 13.5 <![CDATA[M n ]]> 37 <![CDATA[M w ]]> 130 <![CDATA[M z ]]> 350 <![CDATA[M w / M n ]]> 3.6 <![CDATA[M z / M w ]]> 2.7 <![CDATA[M z / M n ]]> 9.5 a-TREF<30 4.3 a-TREF 30-94 65.9 a-TREF>94 29.8 Unsaturated 270 Storage modulus at 10.0 kPa loss modulus 1500 Storage modulus at 1.0 kPa loss modulus 35
[0081] in:
[0082] MFR2 is the melt mass flow rate expressed in g / 10 min measured according to ASTM D1238 (2013) at a temperature of 190°C and a load of 2.16 kg;
[0083] Density is measured according to ASTM D792 (2008) in kg / m 3 express;
[0084] The ethylene unit content refers to the weight of units derived from ethylene present in the polymer, also referred to as the amount of moieties derived from ethylene, expressed in wt% relative to the total weight of the polymer;
[0085] The comonomer content refers to the weight of the units derived from the comonomer present in the polymer, also referred to as the amount of moieties derived from the comonomer, expressed in wt% relative to the total weight of the polymer;
[0086] · Comonomer type refers to the type of comonomer used in the production of the polymer, where C6 is 1-hexene and C8 is 1-octene;
[0087] The comonomer branch content refers to the number of branches per 100 carbon atoms in the polymer, which is expressed by 13 C-NMR to determine;
[0088] ·M n is the number average molecular weight, Mw is the weight average molecular weight, and M z is the z-average molecular weight, where M n 、M w and M z All are expressed in kg / mol and measured according to ASTM D6474 (2012);
[0089] a-TREF<30 refers to the polymer fraction eluted in a-TREF as described above at a temperature of ≤30.0°C, expressed in wt%, and refers to the amorphous fraction of the polymer, calculated by subtracting a-TREF 30-94 and a-TREF>94 from 100.0 wt%;
[0090] a-TREF 30-94 refers to the polymer fraction eluting in a-TREF at temperatures >30.0 and ≤94.0°C, expressed in wt %, and refers to the branched fraction of the polymer;
[0091] a-TREF>94 refers to the polymer fraction eluting in a-TREF at temperatures >94.0 and <140°C, expressed in wt%, and refers to the linear fraction of the polymer;
[0092] Unsaturation refers to the sum of vinyl unsaturation, vinylidene unsaturation, vinylidene unsaturation, trialkyl unsaturation, and is expressed as the number of unsaturations per 1,000,000 chain carbon atoms and is measured on a Bruker Avance 500 spectrophotometer equipped with a cryogenically cooled probe operated at 125°C. 13 C NMR was measured, where the sample was dissolved in C2D2Cl4 containing DBPC as a stabilizer at 130°C.
[0093] Storage modulus and loss modulus were measured using dynamic mechanical spectroscopy (DMS) according to ISO 6721-10 at a temperature of 190°C in a nitrogen environment with a frequency sweep using a parallel plate apparatus, using a frequency range of 0.1-100 rad / s at an oscillation strain of 5%, and are expressed in Pa.
[0094] Polymer (B): SABIC HDPE F00952J: Density: 952kg / m 2 ; MFR2: 0.05 g / 10 min; MFR21 (melt mass flow rate measured at 21.6 kg, 190°): 9.5 g / 10 min.
[0095] Using the above materials, a plurality of 3-layer films and 5-layer films were produced by blown film extrusion at an amount of 500 kg / h, a speed of 73 m / min and a blow-up ratio of 1.9, each having a thickness of 110 μm.
[0096] In the 3-layer film of the example, layer (a) is the first outer layer, layer (c) is the inner layer or core layer, and layer (e) is the second outer layer, wherein the layer sequence is (a)-(c)-(e). In the 5-layer film of the example, layer (a) is the first outer layer, layer (b) is the first intermediate layer, layer (c) is the inner layer or core layer, layer (d) is the second intermediate layer, and layer (e) is the second outer layer, wherein the layer sequence is (a)-(b)-(c)-(d)-(e).
[0097] The composition of the membranes is described in the table below:
[0098]
[0099]
[0100] For each of polymer (A), polymer (B), LDPE, AB and TiO2, the values in the table refer to the wt% of each component relative to the total weight of the layer. The examples represented by epitaxy (c) are comparative examples. All films can be produced with good bubble stability. For the above films, the dart impact strength was tested and the results are given in the following table.
[0101] membrane Dart impact strength (g / μm) 1 5.1 2 4.5 3(c) 3.8 4 4.1 5(c) 2.8 6 4.7 7(c) 3.0 8 5.2 9 4.4 10(c) 2.4 11(c) 4.8
[0102] The above table shows that the bags of the present invention have the desired high dart impact strength while being able to be produced by blown film extrusion at high speeds and high bubble stability.
Claims
1. A bag for storing bulk goods, wherein the bag comprises a multilayer film, the multilayer film comprising: (a) a first outer layer; (c) core layer; and (e) a second outer layer; wherein layers (a), (c) and (e) are placed relative to each other in this order; The multilayer film comprises: • ≥50.0 and ≤80.0 wt% of polymer (A), relative to the total weight of the multilayer film, the polymer (A) comprising a moiety derived from ethylene and a moiety derived from 1-hexene, wherein the polymer (A) has: (i) Measured according to ASTM D792 (2008): ≥910 and ≤930 kg / m 3 density; (ii) a melt mass flow rate of ≥0.5 and ≤5.0 g / 10 min at a temperature of 190° C. and a load of 2.16 kg as measured according to ASTM D1238 (2013); (iii) ≤ 6.0 wt% relative to the total weight of the polymer in a fraction eluting in analytical temperature rising elution fractionation (a-TREF) at a temperature of ≤ 30.0°C; and (iv) ≥ 20.0 wt% of the fraction eluting in a-TREF at a temperature > 94.0°C, relative to the total weight of the polymer; and • ≥ 20.0 and ≤ 50.0 wt% of a polymer (B), relative to the total weight of the multilayer film, the polymer (B) comprising a moiety derived from ethylene and ≥ 0.5 and ≤ 5.0 wt% of a moiety derived from 1-butene, 1-hexene or 1-octene, wherein the polymer (B) has: (v) ≥945 and ≤965 kg / m2 measured according to ASTM D792 (2008) 3 density; (vi) a melt mass flow rate of ≥0.01 and ≤1.00 g / 10 min measured at a temperature of 190° C. and a load of 2.16 kg as measured according to ASTM D1238 (2013); and (vii) a melt mass flow rate of ≥5.0 and ≤50.0 g / 10 min at a temperature of 190° C. and a load of 21.6 kg as measured according to ASTM D1238 (2013); The multilayer film contains no LDPE.
2. The bag of claim 1, wherein the multilayer film consists of layers (a), (c) and (e).
3. The bag according to claim 1, wherein layer (a) and layer (e) each contain ≥75.0 wt% and ≤95.0 wt% of polymer (A), and ≥5.0 and ≤20.0 wt% of polymer (B), wherein the wt% of polymer (A) and (B) are each expressed relative to the total weight of each layer (a) or (e), respectively.
4. The bag according to claim 3, wherein the composition of layer (a) and layer (e) is the same.
5. The bag according to any one of claims 1 to 4, wherein layer (c) comprises ≥ 30.0 and ≤ 70.0 wt% of polymer (A), and ≥ 30.0 and ≤ 70.0 wt% of polymer (B), relative to the total weight of layer (c).
6. The bag according to any one of claims 1 to 4, wherein • the weight of layer (a) is ≥ 10.0 and ≤ 40.0 wt%; and / or • the weight of layer (c) is ≥ 20.0 and ≤ 80.0 wt%; and / or • The weight of layer (e) is ≥ 10.0 and ≤ 40.0 wt%; The weights of layers (a), (c) and (e) are each expressed relative to the total weight of the multilayer film.
7. The bag according to any one of claims 1 to 4, wherein • the thickness of layer (a) is ≥ 10.0 and ≤ 40.0 µm; and / or • the thickness of layer (c) is ≥ 20.0 and ≤ 80.0 µm; and / or •The thickness of layer (e) is ≥10.0 and ≤40.0µm.
8. The bag of claim 1, wherein the multilayer film further comprises: (b) a first intermediate layer; and (d) a second intermediate layer; wherein layer (b) is located between layer (a) and layer (c), and layer (d) is located between layer (c) and layer (e).
9. The bag according to claim 8, wherein layer (b) and layer (d) each contain ≥75.0 wt% and ≤95.0 wt% of polymer (A), or consist of polymer (A), wherein the wt% of each polymer (A) is expressed relative to the total weight of each layer (b) or (d), respectively.
10. The bag according to claim 9, wherein the composition of layer (b) and layer (d) is the same.
11. The bag according to any one of claims 8 to 10, wherein layer (a) and layer (e) each comprise ≥75.0 wt% and ≤95.0 wt% of polymer (A), and ≥5.0 and ≤20.0 wt% of polymer (B), wherein the wt% of each polymer (A) and (B) is expressed relative to the total weight of each layer (a) or (e), respectively.
12. The bag of claim 11, wherein the composition of layer (a) and layer (e) is the same.
13. The bag according to any one of claims 8 to 10, wherein layer (c) comprises ≥ 75.0 wt% and ≤ 99.0 wt% of polymer (A), or consists of polymer (A), wherein the wt% of each polymer (A) is expressed relative to the total weight of layer (c).
14. The bag according to any one of claims 8 to 10, wherein the multilayer film consists of layers (a), (b), (c), (d) and (e).
15. The bag according to any one of claims 8 to 10, wherein • the weight of layer (a) is ≥ 10.0 and ≤ 20.0 wt%; and / or • the weight of layer (b) is ≥ 10.0 and ≤ 20.0 wt%; and / or • the weight of layer (c) is ≥ 20.0 and ≤ 60.0 wt%; and / or • the weight of layer (d) is ≥ 10.0 and ≤ 20.0 wt%; and / or • The weight of layer (e) is ≥ 10.0 and ≤ 20.0 wt%; The weights of the layers (a), (b), (c), (d) and (e) are each expressed relative to the total weight of the multilayer film.
16. The bag according to any one of claims 8 to 10, wherein • the thickness of layer (a) is ≥ 10.0 and ≤ 20.0 µm; and / or • the thickness of layer (b) is ≥ 10.0 and ≤ 20.0 µm; and / or • the thickness of layer (c) is ≥ 20.0 and ≤ 60.0 µm; and / or • the thickness of layer (d) is ≥ 10.0 and ≤ 20.0 µm; and / or •The thickness of layer (e) is ≥10.0 and ≤20.0µm.
17. The bag according to any one of claims 1 to 4, wherein the thickness of the multilayer film is ≥ 70 and ≤ 150 µm.
18. The bag according to any one of claims 8 to 10, wherein the thickness of the multilayer film is ≥ 70 and ≤ 150 µm.
Citation Information
Patent Citations
Multilayer Polyolefin Blown Film
US20120100356A1