General-purpose liquid packaging film and method for producing the same

Abstract

This application provides a general-purpose liquid packaging film, comprising a three-layer co-extruded layer formed by three-layer co-extrusion blown film. The three-layer co-extruded layer includes an inner layer, a middle layer, and an outer layer. The inner layer comprises LLDPE-FG5224, MVLDPE-SP0540, LDPE-2426K, LLDPE-FG5190, and PPA-A1058. The middle layer comprises MLLDPE-1327CA, LLDPE-2056AC, LDPE-2426K, and PPA-A1058. The outer layer comprises LDPE-2426N, LLDPE-7042, MLLDPE-1327CA, and PPA-A1058. This application also provides a method for preparing the general-purpose liquid packaging film. The film produced by the formulation and process provided in this application exhibits physical properties such as tensile strength, elongation at break, and coefficient of friction that are adaptable to the requirements of packaging liquids with different contents, thereby reducing the frequency of formulation changes during production and consequently reducing production costs.

Description

Technical Field

[0001] This invention relates to the technical field of composite flexible packaging films, and specifically to a general-purpose liquid packaging film and its preparation method. Background Technology

[0002] In composite flexible packaging, the contents of the liquid packaging bag vary, and consequently, the requirements for the heat-sealing film also differ. Currently, the common practice is to adjust the film formula according to the different contents. However, in actual production, the formula needs to be constantly changed, which generates a lot of manpower, energy consumption, and efficiency waste, resulting in increased production costs. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a universal liquid packaging film that can perform universal functions for packaging liquids with different contents, thereby reducing the production cost of the film.

[0004] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0005] A general-purpose liquid packaging film includes a three-layer co-extruded layer formed by three-layer co-extrusion blown film, wherein the three-layer co-extruded layer includes an inner layer, a middle layer and an outer layer, and the components of the inner layer include LLDPE-FG5224, MVLDPE-SP0540, LDPE-2426K, LLDPE-FG5190 and PPA-A1058;

[0006] The components of the middle layer include MLLDPE-1327CA, LLDPE-2056AC, LDPE-2426K and PPA-A1058;

[0007] The outer layer comprises LDPE-2426N, LLDPE-7042, MLLDPE-1327CA, and PPA-A1058.

[0008] In some possible implementations, the inner layer comprises, by weight percentage, 30% LLDPE-FG5224, 24.5% MVLDPE-SP0540, 15% LDPE-2426K, 30% LLDPE-FG5190 and 0.5% PPA-A1058.

[0009] By weight percentage, the middle layer comprises 39.5% MLLDPE-1327CA, 40% LLDPE-2056AC, 20% LDPE-2426K and 0.5% PPA-A1058.

[0010] The outer layer comprises, by weight percentage, 19.5% LDPE-2426N, 50% LLDPE-7042, 30% MLLDPE-1327CA and 0.5% PPA-A1058.

[0011] In some possible implementations, the thickness of the inner layer is 30% of the total thickness of the film, the thickness of the middle layer is 40% of the total thickness of the film, and the thickness of the outer layer is 30% of the total thickness of the film.

[0012] This application also provides a method for preparing a universal liquid packaging film, the method comprising the following steps:

[0013] The components of the inner layer are mixed evenly and added to the inner hopper of the three-layer co-extrusion blown film machine;

[0014] The components of the middle layer are mixed evenly and added to the middle layer hopper of the three-layer co-extrusion blown film machine;

[0015] The components of the outer layer are mixed evenly and added to the outer hopper of the three-layer co-extrusion blown film machine;

[0016] The three-layer co-extrusion blown film machine melts and extrudes the components in each hopper through the extrusion screws to the die head to be blown into the film.

[0017] In some possible implementations, the inner screw barrel temperature is 170-180°C, the middle screw barrel temperature is 175-185°C, the outer screw barrel temperature is 165-170°C, the die head runner temperature is 175-180°C, and the die opening temperature is 175°C.

[0018] In some possible implementations, the air-cooling temperature is 15-18°C.

[0019] In some possible implementations, the inflation ratio is 1:1.3 to 1:1.8.

[0020] In some possible implementations, the operating frequency of the cooling fan is greater than or equal to 45Hz.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] In this application, by selecting a film blown from a specific type and model of polyethylene blend, the film's physical properties, such as tensile strength, elongation at break, and coefficient of friction, can be adapted to the requirements of different liquid contents packaging, thereby reducing the frequency of formula switching in the production process. This reduces additional personnel and energy waste, and the film provided by this application also helps to reduce production costs.

[0023] The present invention will be further described in detail below with reference to specific embodiments. Detailed Implementation

[0024] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0026] The following describes some embodiments of the present invention in detail. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] A general-purpose liquid packaging film includes a three-layer co-extruded layer formed by three-layer co-extrusion blown film. The three-layer co-extruded layer comprises an inner layer, a middle layer, and an outer layer. The components of the inner layer include LLDPE-FG5224, MVLDPE-SP0540, LDPE-2426K, LLDPE-FG5190, and PPA-A1058. LLDPE-FG5224 is an abbreviation for linear low-density polyethylene (LLDPE) with the model number FG5224. MVLDPE-SP0540 is an abbreviation for metallocene ultra-low-density polyethylene (ULDPE) with the model number SP0540. LDPE-2426K is an abbreviation for low-density polyethylene (LDPE) with the model number 2426K. LLDPE-FG5190 is an abbreviation for linear low-density polyethylene (LLDPE) with the model number FG5190. PPA is an abbreviation for fluoropolymer processing aid, and A1058 is the model number of PPA. The brand of LLDPE-FG5224 is Borealis, with a melt index of 0.9 g / 10 min and a density of 0.922 g / cm³. 3 The melting point is 113℃. MVLDPE-SP0540 is from the Japanese brand Primavis, and its corresponding melt index is 3.8 g / 10 min, and its density is 0.903 g / cm³. 3 Its melting point is 98℃. LDPE-2426K is from CNOOC Shell, and correspondingly has a melt index of 4 g / 10 min and a density of 0.925 g / cm³. 3 The melting point is 110-112℃. LLDPE-FG5190 is branded by Borealis, and its corresponding melt index is 1.2 g / 10 min, and its density is 0.919 g / cm³. 3It has a melting point of 110℃. The brand of PPA-A1058 is Beijing Yalun.

[0028] The middle layer components include MLLDPE-1327CA, LLDPE-2056AC, LDPE-2426K, and PPA-A1058. MLLDPE-1327CA is an abbreviation for metallurgical linear low-density polyethylene (LLDPE) of type 1327CA. LLDPE-2056AC is an abbreviation for linear low-density polyethylene of type 2056AC. LDPE-2426K is an abbreviation for low-density polyethylene of type 2426K. MLLDPE-1327CA is branded by ExxonMobil, with a melt index of 1.3 g / 10 min and a melting point of 140°C. LLDPE-2056AC is branded by ExxonMobil, with a melt index of 1.0 g / 10 min and a density of 0.92 g / cm³. 3 Its melting point is 121℃. LDPE-2426K is from CNOOC Shell, and correspondingly has a melt index of 4 g / 10 min and a density of 0.925 g / cm³. 3 Its melting point is 110-112℃.

[0029] The outer layer components include LDPE-2426N, LLDPE-7042, MLLDPE-1327CA, and PPA-A1058. LDPE-2426N is an abbreviation for low-density polyethylene (LDPE) of type 2426N. LLDPE-7042 is an abbreviation for linear low-density polyethylene (LLDPE) of type 7042. MLLDPE-1327CA is an abbreviation for pirimicarb-metallic LLDPE of type 1327CA. LDPE-2426N is sourced from CNOOC Shell, with a melt index of 4 g / 10 min and a melting point of 110-112°C. LLDPE-7042 is manufactured by Maoming Petrochemical, with a melt index of 2 g / 10 min and a melting point of 110°C. MLLDPE-1327CA is from ExxonMobil, with a melt index of 1.3 g / 10 min and a melting point of 140°C. PPA-A1058 is branded by Beijing Yalen.

[0030] The inner layer comprises, by weight percentage, 30% LLDPE-FG5224, 24.5% MVLDPE-SP0540, 15% LDPE-2426K, 30% LLDPE-FG5190 and 0.5% PPA-A1058.

[0031] The middle layer comprises, by weight percentage, 39.5% MLLDPE-1327CA, 40% LLDPE-2056AC, 20% LDPE-2426K and 0.5% PPA-A1058.

[0032] The outer layer comprises, by weight percentage, 19.5% LDPE-2426N, 50% LLDPE-7042, 30% MLLDPE-1327CA and 0.5% PPA-A1058.

[0033] The thickness of the inner layer is 30% of the total thickness of the film, the thickness of the middle layer is 40% of the total thickness of the film, and the thickness of the outer layer is 30% of the total thickness of the film.

[0034] Another embodiment of this application provides a method for preparing a universal liquid packaging film. It is understood that the raw materials used in this method are derived from the components of each layer of the universal liquid packaging film in corresponding proportions, and therefore will not be described in detail here. The preparation method includes the following steps:

[0035] The components of the inner layer are mixed evenly and added to the inner layer hopper of the three-layer co-extrusion blown film machine. The temperature of the inner layer screw barrel is set to 170-180℃.

[0036] Mix the components of the middle layer evenly and add them to the middle layer hopper of the three-layer co-extrusion blown film machine. Set the temperature of the middle layer screw barrel to 175-185℃.

[0037] The components of the outer layer are mixed evenly and added to the outer layer hopper of the three-layer co-extrusion blown film machine. The temperature of the outer layer screw barrel is set to 165-170℃.

[0038] The three-layer co-extrusion blown film mill uses extrusion screws to melt and extrude the components in each hopper to the die head for blown film formation. Specifically, the screw corresponding to the inner hopper extrudes the material from the inner hopper, the screw corresponding to the middle hopper extrudes the material from the middle hopper, and the screw corresponding to the outer hopper extrudes the material from the outer hopper. The die head runner temperature is 175-180℃, and the die opening temperature is 175℃. These temperature settings stabilize the film bubble of the formulation while ensuring appropriate cooling efficiency, thus guaranteeing film forming quality. The air cooling temperature is 15-18℃, which reduces energy consumption while providing good cooling for the formulation. The blow-up ratio is 1:1.3-1:1.8, which is beneficial for improving film quality. The cooling fan operates at a frequency greater than or equal to 45Hz. Existing equipment can be used for the three-layer co-extrusion blown film mill, therefore its specific structure will not be described in detail.

[0039] The film provided in this application has a transverse tensile strength ≥38 Newtons, a longitudinal tensile strength ≥39 Newtons, a dynamic friction coefficient of 0.11-0.13, a transverse elongation at break ≥1150%, and a longitudinal elongation at break ≥1000% when the thickness is 10C (0.1 mm).

[0040] In this application, by selecting a film blown from a specific type and model of polyethylene blend, the film's physical properties, such as tensile strength, elongation at break, and coefficient of friction, can be adapted to the requirements of different liquid contents packaging, thereby reducing the frequency of formula switching in the production process. This reduces additional personnel and energy waste, and the film provided by this application also helps to reduce production costs.

[0041] In addition, the selection of interlayer raw materials is crucial. Different types of raw materials require different temperatures in each temperature zone. High temperatures can cause the film bubble to become unstable and make cooling more difficult, while low temperatures can result in insufficient temperature. Calculating the temperature based on the melt index is not practical and requires testing and repeated testing.

[0042] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A general-purpose liquid packaging film, comprising a three-layer co-extruded layer formed by three-layer co-extrusion blown film, wherein the three-layer co-extruded layer includes an inner layer, a middle layer, and an outer layer, characterized in that, The inner layer comprises LLDPE-FG5224, MVLDPE-SP0540, LDPE-2426K, LLDPE-FG5190, and PPA-A1058. By mass percentage, the inner layer comprises 30% LLDPE-FG5224, 24.5% MVLDPE-SP0540, 15% LDPE-2426K, 30% LLDPE-FG5190, and 0.5% PPA-A1058. The middle layer comprises MLLDPE-1327CA, LLDPE-2056AC, LDPE-2426K and PPA-A1058, and by mass percentage, the middle layer comprises 39.5% MLLDPE-1327CA, 40% LLDPE-2056AC, 20% LDPE-2426K and 0.5% PPA-A1058. The outer layer comprises LDPE-2426N, LLDPE-7042, MLLDPE-1327CA, and PPA-A1058, and by mass percentage, the outer layer comprises 19.5% LDPE-2426N, 50% LLDPE-7042, 30% MLLDPE-1327CA, and 0.5% PPA-A1058.

2. The universal liquid packaging film as described in claim 1, characterized in that, The thickness of the inner layer is 30% of the total thickness of the film, the thickness of the middle layer is 40% of the total thickness of the film, and the thickness of the outer layer is 30% of the total thickness of the film.

3. A method for preparing a general-purpose liquid packaging film, characterized in that, The method for preparing the universal liquid packaging film as described in any one of claims 1 to 2 comprises the following steps: The components of the inner layer are mixed evenly and added to the inner hopper of the three-layer co-extrusion blown film machine; The components of the middle layer are mixed evenly and added to the middle layer hopper of the three-layer co-extrusion blown film machine; The components of the outer layer are mixed evenly and added to the outer hopper of the three-layer co-extrusion blown film machine; The three-layer co-extrusion blown film machine melts and extrudes the components in each hopper through the extrusion screws to the die head to be blown into the film.

4. The preparation method according to claim 3, characterized in that, The inner screw barrel temperature is 170-180℃, the middle screw barrel temperature is 175-185℃, the outer screw barrel temperature is 165-170℃, the die head flow channel temperature is 175-180℃, and the die opening temperature is 175℃.

5. The preparation method according to claim 4, characterized in that, The air-cooled temperature is 15-18℃.

6. The preparation method according to claim 5, characterized in that, The inflation ratio is 1:1.3 to 1:1.

8.

7. The preparation method according to claim 6, characterized in that, The operating frequency of the cooling fan is greater than or equal to 45Hz.