Polyethylene toughened high-temperature cooking film with high barrier function, production process and application

Abstract

This invention discloses a high-barrier polyethylene toughened high-temperature retort film. The film, from top to bottom, comprises a composite layer, a first barrier layer, a reinforcing support layer, a second barrier layer, and a heat-sealing layer. The composite layer, the first barrier layer, and the second barrier layer are all made of PE blends. The reinforcing support layer is made of a blend of SEBS and PE, and the heat-sealing layer is made of a blend of PE and PP. The film prepared by this invention can withstand high-temperature retort at 121-125℃ for 40 minutes and low-temperature storage at -18℃. It also possesses high toughness, withstands 3-4m drops at room temperature, and exhibits high barrier properties, excellent solvent penetration resistance, and heat-sealing performance. It is self-sealing and can be well heat-sealed with both PP and PE.

Description

Technical Field

[0001] This invention belongs to the field of film technology, specifically relating to a high-barrier polyethylene toughened high-temperature retort film, its production process, and its application. Background Technology

[0002] Packaged food is widely used in people's daily lives, and the use of composite flexible films for packaging is increasing, gradually occupying an important position. High-temperature retort pouches are a type of composite film flexible packaging. This type of flexible packaging typically uses vacuum packaging, and may then undergo high-temperature sterilization before being stored at room temperature, depending on the needs. Existing retort pouches are composed of multiple substrates, commonly including PE, PA, PET, AL, and CPP. Common structures include two-layer, three-layer, and four-layer composite films. However, existing composite films suffer from poor resistance to high and low temperatures, easily softening and deforming during high-temperature cooking, becoming brittle and cracking during low-temperature freezing, having low heat-sealing strength, poor impact resistance, and resulting in poor sealing and barrier properties, making the packaging bags prone to breakage and leakage / spoilage of the contents. Summary of the Invention

[0003] To address the problems existing in the prior art, the purpose of this invention is to provide a toughened high-temperature retort film of polyethylene with high barrier function, as well as its production process and application, which is specifically achieved through the following technical solutions:

[0004] The first aspect of the present invention provides a toughened high-temperature retort film of polyethylene with high barrier function. The film comprises, from top to bottom, a composite layer, a first barrier layer, a reinforcing support layer, a second barrier layer, and a heat-sealing layer. The composite layer, the first barrier layer, and the second barrier layer are all made of PE blends. The reinforcing support layer is made of a blend of SEBS and PE. The heat-sealing layer is made of a blend of PE and PP.

[0005] Furthermore, the PE blend of the composite layer includes 30-50% HDPE and 50-70% MDPE.

[0006] Furthermore, the raw materials and proportions of the first and second barrier layers are the same, including 60-80% HDPE and 20-40% MDPE.

[0007] Furthermore, the blends that reinforce the support layer include 20-25% SEBS and 75-80% MDPE.

[0008] Furthermore, the heat-sealing blend comprises 60-80% PE and 20-40% PP.

[0009] Furthermore, the composite layer has a thickness of 10-15 micrometers, the first and second barrier layers have a thickness of 5-10 micrometers, the reinforcing support layer has a thickness of 20-30 micrometers, and the heat-sealing layer has a thickness of 15-25 micrometers.

[0010] A second aspect of the present invention provides a production process for a toughened high-temperature retort film of polyethylene with high barrier function, wherein the process involves co-extrusion blow molding of the raw materials of the composite layer, the first barrier layer, the reinforcing support layer, the second barrier layer, and the heat-sealing layer as described in any one of claims 1-6.

[0011] Furthermore, the production process uses five extruders to extrude the composite layer, the first barrier layer, the reinforcing support layer, the second barrier layer, and the heat-sealing layer, respectively. The screw diameters of the five extruders are 65mm, 55mm, 75mm, 65mm, and 55mm, respectively.

[0012] A third aspect of the present invention provides the application of a high-barrier polyethylene toughened high-temperature retort film in food or pharmaceutical packaging, wherein the food includes retortable food, liquid food, frozen food, or food requiring moisture protection, and the pharmaceutical is a liquid pesticide product.

[0013] Furthermore, the steamed or boiled foods include, but are not limited to, meat and poultry, and the liquid foods include, but are not limited to, soy milk, beverages, and nutrient solutions.

[0014] The film prepared by the formula of this invention can withstand high temperature cooking at 121-125℃ for 40 minutes and low temperature storage at -18℃. It also has high toughness, can withstand 3-4m room temperature drop, and has high barrier properties, excellent solvent penetration resistance and heat sealing performance. It is self-sealing and can be heat-sealed well with PP and PE. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments in order to better understand the technical solution.

[0016] This invention discloses a high-barrier polyethylene toughened high-temperature retort film, comprising, from top to bottom, a composite layer, a first barrier layer, a reinforcing support layer, a second barrier layer, and a heat-sealing layer. The composite layer, the first barrier layer, and the second barrier layer are all made of PE blends, the reinforcing support layer is made of a blend of SEBS and PE, and the heat-sealing layer is made of a blend of PE and PP.

[0017] The manufacturing process is as follows: the composite layer, first barrier layer, reinforcing support layer, second barrier layer, and heat-sealing layer are mixed separately, conveyed, extruded, blow-molded, automatically measured, cooled, traction, surface treated, bundled, slit, wound, packaged, and stored. Five extruders extrude the composite layer, first barrier layer, reinforcing support layer, second barrier layer, and heat-sealing layer respectively. The screw diameters of the five extruders are 65mm, 55mm, 75mm, 65mm, and 55mm respectively. The equipment temperature settings are: Zone 1: 175℃, Zone 2: 180℃, Zone 3: 190℃, Zone 4: 190℃, Zone 5: 190℃, Zone 6: 190℃, and the die temperature is 190℃. Example

[0018] A high-barrier polyethylene toughened high-temperature retort film comprises, from top to bottom, a 15-micron composite layer, a 5-micron first barrier layer, a 30-micron reinforcing support layer, a 10-micron second barrier layer, and a 25-micron heat-sealing layer. The composite layer comprises 50% HDPE and 50% MDPE; the first barrier layer comprises 80% HDPE and 20% MDPE; the reinforcing support layer comprises 20% SEBS and 80% MDPE; the second barrier layer comprises 70% HDPE and 30% MDPE; and the heat-sealing layer comprises 80% PE and 20% PP.

[0019] The barrier properties of the film prepared in this embodiment are compared with those of CPP and PE of the same thickness on the market. The results are shown in Table 1.

[0020] Table 1

[0021]

[0022] As shown in Table 1, the product prepared by the formulation of this invention significantly improves the oxygen barrier effect, extends the shelf life and aroma retention of food compared to polyethylene and polypropylene films of the same thickness. It can replace high-barrier multilayer co-extruded films such as NY and EVOU. Example

[0023] A high-barrier polyethylene toughened high-temperature retort film comprises, from top to bottom, a 15-micron composite layer, a 10-micron first barrier layer, a 30-micron reinforcing support layer, a 10-micron second barrier layer, and a 20-micron heat-sealing layer. The composite layer comprises 50% HDPE and 50% MDPE; the first barrier layer comprises 70% HDPE and 30% MDPE; the reinforcing support layer comprises a blend of 25% SEBS and 75% MDPE; the second barrier layer comprises 80% HDPE and 20% MDPE; and the heat-sealing layer comprises 60% PE and 40% PP.

[0024] This embodiment was subjected to a drop resistance test against existing PE12 / NY15 / RCPP80 high-temperature sterilized soy milk bags. The results of the drop resistance test are shown in Table 2.

[0025] Table 2

[0026]

[0027] Table 2 shows that the film produced using this invention significantly reduces the breakage rate of soymilk bag packaging, solving the long-standing problem of high storage and transportation losses. It also solves the problem of not being able to be refrigerated. This provides a practical solution for soymilk manufacturers to reduce costs and expand their sales areas.

Claims

1. A high-barrier polyethylene toughened high-temperature retort film, characterized in that, The film, from top to bottom, consists of a composite layer, a first barrier layer, a reinforcing support layer, a second barrier layer, and a heat-sealing layer. The composite layer, the first barrier layer, and the second barrier layer are all made of PE blends. The reinforcing support layer is made of a blend of SEBS and PE. The heat-sealing layer is made of a blend of PE and PP. The reinforcing support layer blend comprises 20-25% SEBS and 75-80% MDPE; the heat-sealing layer blend comprises 60-80% PE and 20-40% PP; the composite layer PE blend comprises 30-50% HDPE and 50-70% MDPE; the first and second barrier layers have the same raw materials and proportions, comprising 60-80% HDPE and 20-40% MDPE; the composite layer has a thickness of 10-15 micrometers, the first and second barrier layers have a thickness of 5-10 micrometers, the reinforcing support layer has a thickness of 20-30 micrometers, and the heat-sealing layer has a thickness of 15-25 micrometers.

2. A production process for a high-barrier polyethylene toughened high-temperature retort film as described in claim 1, characterized in that... The process involves co-extruding and blow molding of the composite layer, first barrier layer, reinforcing support layer, second barrier layer, and heat-sealing layer as described in claim 1.

3. The production process as described in claim 2, characterized in that... The production process uses five extruders to extrude the composite layer, the first barrier layer, the reinforcing support layer, the second barrier layer, and the heat-sealing layer, respectively. The screw diameters of the five extruders are 65mm, 55mm, 75mm, 65mm, and 55mm, respectively.

4. The application of the high-barrier polyethylene toughened high-temperature retort film of claim 1 in food or pharmaceutical packaging, wherein the food includes retort food, liquid food, frozen food or food requiring moisture protection, and the pharmaceutical is a liquid pesticide product.

5. The application as described in claim 4, wherein the steamed or boiled food includes meat and poultry, and the liquid food includes beverages.

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