Polyethylene composite film resistant to high-temperature steaming and boiling as well as preparation method and application of polyethylene composite film

Abstract

The invention relates to a polyethylene composite film resistant to high-temperature steaming and boiling as well as a preparation method and application of the polyethylene composite film, and relates to the technical field of film materials. The polyethylene composite film resistant to high-temperature cooking comprises the following components: 75-85 parts of metallocene high-density polyethylene, 8-12 parts of metallocene low-density polyethylene, 5-10 parts of styrene block thermoplastic elastomer, 4-7 parts of composite filler, 1-3 parts of a compatilizer, 0.2-0.5 part of an antioxidant and 0.3-0.6 part of a lubricant. On the basis of an existing polyethylene film material formula system, the specific composite filler and the styrene block thermoplastic elastomer are mainly introduced, all the components are in synergistic interaction, the high-temperature steaming resistance and the water vapor barrier property of the polyethylene film material are remarkably improved, and the use requirement of a polyethylene steaming film can be met; the method can be widely applied to preparation of various cooking-resistant packaging materials such as cooking packaging bags and the like, and has wide application.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane materials, in particular to a high-temperature cooking-resistant polyethylene composite film and a preparation method and application thereof. Background Art

[0002] Packaging materials play a crucial role in numerous fields, including food and pharmaceuticals. They must not only protect products from environmental influences but also meet performance requirements under specific processing and usage conditions. Retort-resistant packaging, in particular, has garnered significant attention in recent years, particularly in areas such as food sterilization and long-term storage, as well as in aseptic packaging for pharmaceutical products.

[0003] Polyethylene (PE), a common plastic material, has been widely used in the packaging field due to its advantages such as low cost, good processing performance, and strong chemical stability. However, traditional polyethylene film materials have significant deficiencies in high-temperature cooking resistance and water vapor barrier properties. During high-temperature cooking, the polyethylene molecular chains are prone to intensified thermal motion and chain segment relaxation, resulting in a significant decrease in the mechanical properties of the film material, such as reduced tensile strength and elongation at break. It may even cause film rupture and delamination, failing to meet the requirements for material integrity and stability during cooking and packaging. Furthermore, the polyethylene material itself has limited water vapor barrier capabilities. During storage, external water vapor can easily penetrate the film material and enter the packaging, affecting product quality and shelf life.

[0004] In order to improve the high-temperature cooking resistance and water vapor barrier properties of polyethylene film materials, researchers have conducted extensive research and exploration. Currently, common methods include adding inorganic fillers, blending modification, and using multi-layer co-extrusion technology. For example, adding inorganic fillers such as calcium carbonate and talc can improve the strength and rigidity of polyethylene films to a certain extent. However, these fillers have poor compatibility with the polyethylene matrix, which can easily lead to uneven dispersion of the fillers in the matrix, thereby affecting the overall performance of the film material and having limited effect in improving the high-temperature cooking resistance and water vapor barrier properties. Blending modification involves blending polyethylene with other polymers, such as ethylene-vinyl acetate copolymer (EVA) and ethylene-vinyl alcohol copolymer. Although this can improve certain properties of the film material to a certain extent, it is often difficult to simultaneously achieve both high-temperature cooking resistance and water vapor barrier properties. Multi-layer co-extrusion technology combines polymer layers with different properties to form a multi-layer structured film material, which can improve the overall performance of the film to a certain extent. However, this technology is complex, has high equipment costs, and relatively low production efficiency, which limits its large-scale application.

[0005] Therefore, it is of great practical significance to develop a polyethylene composite film material with excellent high-temperature cooking resistance and water vapor barrier properties, good processing performance and reasonable cost. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a high-temperature cooking-resistant polyethylene composite film and a preparation method and application thereof.

[0007] In a first aspect, the present invention provides a high-temperature cooking resistant polyethylene composite film, which comprises the following components in parts by weight:

[0008] 75-85 parts of metallocene high-density polyethylene, 8-12 parts of metallocene low-density polyethylene, 5-10 parts of styrene block thermoplastic elastomer, 4-7 parts of composite filler, 1-3 parts of compatibilizer, 0.2-0.5 parts of antioxidant and 0.3-0.6 parts of lubricant;

[0009] The composite filler is obtained by subjecting layered silicate and tetrapod-shaped zinc oxide whisker in a weight ratio of (5-10):(2-3) to silane coupling treatment.

[0010] Furthermore, the high temperature cooking resistant polyethylene composite film comprises the following components in parts by weight:

[0011] 81 parts of metallocene high-density polyethylene, 10 parts of metallocene low-density polyethylene, 8 parts of styrene block thermoplastic elastomer, 5.5 parts of composite filler, 2 parts of compatibilizer, 0.3 parts of antioxidant and 0.5 parts of lubricant.

[0012] Furthermore, the preparation method of the composite filler comprises the following steps:

[0013] The layered silicate and the tetrapod-shaped zinc oxide whiskers are mixed to obtain a dry mixture;

[0014] dissolving a silane coupling agent in an ethanol aqueous solution having a volume fraction of 80 to 90% to obtain a silane coupling agent solution;

[0015] The dry mix is ​​added to the silane coupling agent solution and stirred, and then allowed to stand, filtered and dried to obtain the composite filler.

[0016] Furthermore, the silane coupling agent is composed of γ-aminopropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane in a weight ratio of 2:1, the weight ratio of the dry mix to the silane coupling agent solution is 1:(3-5), and the weight percentage of the silane coupling agent in the silane coupling agent solution is 5-10%.

[0017] Furthermore, the weight ratio of the layered silicate to the tetrapod-shaped zinc oxide whiskers is 7:2.5.

[0018] Furthermore, the metallocene high-density polyethylene includes Total's product model M4707EP, the metallocene low-density polyethylene includes Exxon's product model E1018MA, the styrene block thermoplastic elastomer includes Japan's Kuraray's product model 4055, the compatibilizer includes maleic anhydride grafted polyethylene, and the layered silicate includes at least one of montmorillonite and mica flakes.

[0019] Furthermore, the antioxidant is composed of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:2, and the lubricant is composed of ethylene bisstearamide and pentaerythritol stearate in a weight ratio of (2-3):1.

[0020] In a second aspect, based on the same inventive concept, the present invention provides a method for preparing a high-temperature cooking-resistant polyethylene composite film according to any one of the first aspects, the method for preparing the high-temperature cooking-resistant polyethylene composite film comprising the following steps:

[0021] The components are added into a film blowing machine in proportion, melt co-extruded, blown into a film from a film head, and then subjected to cast molding, traction cooling, trimming, winding and cutting processes to obtain the high-temperature cooking resistant polyethylene composite film.

[0022] Furthermore, the working condition parameters of the film blowing machine include: screw speed of 300-450 rpm, barrel temperature of 190-195° C., die head temperature of 195-200° C., and blow-up ratio of 2-2.5.

[0023] In a third aspect, an embodiment of the present invention provides the use of the high-temperature cooking-resistant polyethylene composite film described in any one of the first aspects or the high-temperature cooking-resistant polyethylene composite film prepared by the preparation method of the high-temperature cooking-resistant polyethylene composite film described in any one of the second aspects in the preparation of cooking packaging bags.

[0024] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0025] The embodiments of the present invention provide a high-temperature retort-resistant polyethylene composite film, its preparation method, and application. Based on the existing polyethylene film material formulation system, the present invention primarily introduces specific composite fillers and styrene block thermoplastic elastomers, with the components synergistically enhancing each other, significantly improving the high-temperature retort resistance and water vapor barrier properties of the polyethylene film material. This meets the requirements for the use of polyethylene retort film and can be widely used in the preparation of various retort-resistant packaging materials, such as retort packaging bags, and has a wide range of uses. Specifically:

[0026] 1) Composite Filler: Silane-coupled composite fillers form a good interfacial bond with the polyethylene matrix. The uniform dispersion of layered silicate and tetrapod-shaped zinc oxide whiskers in appropriate proportions within the polyethylene matrix not only improves the mechanical properties of the composite film but also enhances its resistance to high-temperature cooking. During the high-temperature cooking process, the filler restricts the movement of the polyethylene molecular chains, improving the uniformity and stability of the overall material performance and preventing deformation and softening of the film. Furthermore, the barrier effect of the layered silicate synergizes with the inherent barrier properties of the polyethylene matrix, further enhancing the film's water vapor barrier properties.

[0027] 2) Styrene block thermoplastic elastomers: Styrene block thermoplastic elastomers such as Japan Kuraray's product model 4055 play a synergistic toughening and strengthening role with the polyethylene matrix and composite fillers, which can make up for the rigidity of the polyethylene matrix and composite fillers and further enhance the comprehensive performance of the polyethylene composite film. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0029] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0030] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the invention. The experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national standards. If there are no corresponding national standards, then the methods are carried out in accordance with general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0031] The main raw material information involved in the examples and comparative examples of the present invention is as follows:

[0032] The metallocene high-density polyethylene is a product of Total, model M4707EP.

[0033] The metallocene low-density polyethylene is selected from Exxon's product model E1018MA.

[0034] The styrene block thermoplastic elastomer is selected from the product model 4055 of Kuraray of Japan.

[0035] The compatibilizer is maleic anhydride grafted polyethylene.

[0036] The layered silicate is montmorillonite with a particle size of 325 mesh.

[0037] The diameter of the tetrapod-shaped ZnO whiskers is 0.5-5 μm.

[0038] The antioxidant consists of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:2.

[0039] The lubricant is composed of ethylene bisstearamide and pentaerythritol stearate in a weight ratio of 2.5:1.

[0040] The silane coupling agent is composed of gamma-aminopropyltriethoxysilane and gamma-glycidyloxypropyltrimethoxysilane in a weight ratio of 2:1.

[0041] Example 1

[0042] This example provides a high-temperature cooking resistant polyethylene composite film, which comprises the following components in parts by weight:

[0043] 81 parts of metallocene high-density polyethylene, 10 parts of metallocene low-density polyethylene, 8 parts of styrene block thermoplastic elastomer, 5.5 parts of composite filler, 2 parts of compatibilizer, 0.3 parts of antioxidant and 0.5 parts of lubricant;

[0044] The composite filler is obtained by silane coupling treatment of layered silicate and tetrapod-shaped zinc oxide whiskers in a weight ratio of 7:2.5. The preparation method of the composite filler comprises the following steps:

[0045] The layered silicate and the tetrapod-shaped zinc oxide whiskers are mixed to obtain a dry mixture;

[0046] Dissolving a silane coupling agent in an ethanol aqueous solution having a volume fraction of 85% to obtain a silane coupling agent solution having a weight fraction of 8.5%;

[0047] The dry blend was added to the silane coupling agent solution and stirred for 45 minutes at a stirring speed of 200 rpm. The weight ratio of the dry blend to the silane coupling agent solution was 1:4. The mixture was then allowed to stand for 2 hours, filtered, and dried to obtain the composite filler.

[0048] The preparation method of the high temperature resistant cooking polyethylene composite film comprises the following steps:

[0049] The components were added into the film blowing machine in proportion and then melt co-extruded and blown into film from the film head. The screw speed was 400 rpm, the barrel temperature was 193°C, the die temperature was 198°C, and the blow-up ratio was 2.1. The film was then cast at a main machine speed of 20 m / min, and traction cooling, trimming, winding and cutting were carried out at a traction speed of 22 m / min to obtain a high-temperature cooking-resistant polyethylene composite film with a thickness of 50 μm.

[0050] Example 2

[0051] This example provides a high-temperature cooking resistant polyethylene composite film, which comprises the following components in parts by weight:

[0052] 75 parts of metallocene high-density polyethylene, 8 parts of metallocene low-density polyethylene, 5 parts of styrene block thermoplastic elastomer, 4 parts of composite filler, 1 part of compatibilizer, 0.2 parts of antioxidant and 0.3 parts of lubricant;

[0053] The composite filler is obtained by subjecting layered silicate and tetrapod-shaped zinc oxide whiskers in a weight ratio of 5:2 to silane coupling treatment. The preparation method of the composite filler is the same as that of Example 1.

[0054] The preparation method of the high temperature resistant cooking polyethylene composite film comprises the following steps:

[0055] The components were added into a film blowing machine in proportion and then melt co-extruded and blown into a film from the film head. The screw speed was 300 rpm, the barrel temperature was 195°C, the die head temperature was 200°C, and the blow-up ratio was 2.0. The film was then cast at a main machine speed of 20 m / min, and then traction cooled, trimmed, wound, and cut at a traction speed of 22 m / min to obtain a high-temperature cooking-resistant polyethylene composite film with a thickness of 50 μm.

[0056] Example 3

[0057] This example provides a high-temperature cooking resistant polyethylene composite film, which comprises the following components in parts by weight:

[0058] 75 parts of metallocene high-density polyethylene, 8 parts of metallocene low-density polyethylene, 5 parts of styrene block thermoplastic elastomer, 4 parts of composite filler, 1 part of compatibilizer, 0.2 parts of antioxidant and 0.3 parts of lubricant;

[0059] The composite filler is obtained by subjecting layered silicate and tetrapod-shaped zinc oxide whiskers in a weight ratio of 10:3 to silane coupling treatment. The preparation method of the composite filler is the same as that of Example 1.

[0060] The preparation method of the high temperature resistant cooking polyethylene composite film comprises the following steps:

[0061] The components were added into the film blowing machine in proportion and then melt co-extruded and blown into film from the film head. The screw speed was 450 rpm, the barrel temperature was 195°C, the die head temperature was 200°C, and the blow-up ratio was 2.5. The film was then cast at a main machine speed of 20 m / min, and then traction cooling, trimming, winding and cutting were carried out at a traction speed of 22 m / min to obtain a high-temperature cooking-resistant polyethylene composite film with a thickness of 50 μm.

[0062] Comparative Example 1

[0063] This example provides a high-temperature cooking-resistant polyethylene composite film and a preparation method thereof. The only difference from Example 1 is that the amount of tetrapod-shaped zinc oxide whiskers is adjusted to 0 (i.e., the filler is only layered silicate obtained by silane coupling treatment, and no tetrapod-shaped zinc oxide whiskers are added); the remaining steps and parameters are the same.

[0064] Comparative Example 2

[0065] This example provides a high-temperature cooking-resistant polyethylene composite film and a preparation method thereof. The only difference from Example 1 is that the composite filler is obtained by silane coupling treatment of layered silicate and tetrapod-shaped zinc oxide whiskers in a weight ratio of 7:5 (that is, the proportion of tetrapod-shaped zinc oxide whiskers in the composite filler is too high); the remaining steps and parameters are the same.

[0066] Comparative Example 3

[0067] This example provides a high-temperature cooking-resistant polyethylene composite film and a preparation method thereof. The only difference from Example 1 is that the amount of styrene block thermoplastic elastomer is adjusted to 0 parts (i.e., no styrene block thermoplastic elastomer is added); the remaining steps and parameters are the same.

[0068] Test Example 1

[0069] In this example, according to existing test methods such as GB / T1040.2-2006 "Determination of tensile properties of plastics", the high-temperature cooking-resistant polyethylene composite films obtained in the above examples and comparative examples were tested for tensile strength mechanical properties before cooking and after cooking at 130°C. The test results are shown in Table 1 below.

[0070] Table 1 Mechanical properties test results before and after cooking of Examples 1 to 3 and Comparative Examples 1 to 3

[0071]

[0072] As can be seen from Table 1, compared with Comparative Examples 1 to 3, the mechanical properties of the high-temperature cooking-resistant polyethylene composite films provided by Examples 1 to 3 of the present invention are better, and the retention rate of the tensile strength after cooking at 130°C is better, indicating that they have good cooking resistance and can have better stability in high temperature and high humidity environments.

[0073] Test Example 2

[0074] On the basis of test example 1, this example further tests the water vapor transmission rate (g / (m2) of the high temperature cooking resistant polyethylene composite film provided in Examples 1 to 3 at a temperature of 23°C and a relative humidity of 85% according to the infrared detector method for determining the water vapor transmission rate of plastic film and sheeting in accordance with GB / T26253-2010. 2 ·24h)), the test results are shown in Table 2.

[0075] Table 2 Water vapor transmission rate test results of Examples 1 to 3

[0076] Test samples <![CDATA[Water vapor transmission rate (g / (m 2 ·24h))]]> Example 1 1.10 Example 2 1.27 Example 3 1.21

[0077] As shown in Table 2, the high-temperature retort-resistant polyethylene composite films provided by Examples 1 to 3 of the present invention have excellent water vapor barrier properties, can meet the use requirements of polyethylene retort films, and can be widely used in the preparation of various retort-resistant packaging materials such as retort packaging bags.

[0078] In summary, the embodiments of the present invention provide a high-temperature cooking-resistant polyethylene composite film, a preparation method and application thereof. Based on the existing polyethylene film material formula system, the present invention mainly introduces specific composite fillers and styrene block thermoplastic elastomers, and the components synergize with each other to significantly improve the high-temperature cooking resistance and water vapor barrier properties of the polyethylene film material, which can meet the use requirements of polyethylene cooking film and can be widely used in the preparation of various types of cooking-resistant packaging materials such as cooking packaging bags, and has a wide range of uses.

[0079] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in a range format is only for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention; therefore, the range description should be considered to have specifically disclosed all possible subranges and single numerical values ​​within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it is intended to include any cited numeral (fractional or integer) within the indicated range.

[0080] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A high temperature resistant cooking polyethylene composite film, characterized in that: The high temperature cooking resistant polyethylene composite film comprises the following components in parts by weight: 75-85 parts of metallocene high-density polyethylene, 8-12 parts of metallocene low-density polyethylene, 5-10 parts of styrene block thermoplastic elastomer, 4-7 parts of composite filler, 1-3 parts of compatibilizer, 0.2-0.5 parts of antioxidant and 0.3-0.6 parts of lubricant; The composite filler is obtained by subjecting layered silicate and tetrapod-shaped zinc oxide whisker in a weight ratio of (5-10):(2-3) to silane coupling treatment.

2. The high temperature cooking resistant polyethylene composite film according to claim 1, characterized in that: The high temperature cooking resistant polyethylene composite film comprises the following components in parts by weight: 81 parts of metallocene high-density polyethylene, 10 parts of metallocene low-density polyethylene, 8 parts of styrene block thermoplastic elastomer, 5.5 parts of composite filler, 2 parts of compatibilizer, 0.3 parts of antioxidant and 0.5 parts of lubricant.

3. The high temperature cooking resistant polyethylene composite film according to claim 1, characterized in that: The preparation method of the composite filler comprises the following steps: The layered silicate and the tetrapod-shaped zinc oxide whiskers are mixed to obtain a dry mixture; dissolving a silane coupling agent in an ethanol aqueous solution having a volume fraction of 80 to 90% to obtain a silane coupling agent solution; The dry mix is ​​added to the silane coupling agent solution and stirred, and then allowed to stand, filtered and dried to obtain the composite filler.

4. The high temperature cooking resistant polyethylene composite film according to claim 3, characterized in that: The silane coupling agent is composed of γ-aminopropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane in a weight ratio of 2:1, the weight ratio of the dry mix to the silane coupling agent solution is 1:(3-5), and the weight percentage of the silane coupling agent in the silane coupling agent solution is 5-10%.

5. The high temperature cooking resistant polyethylene composite film according to claim 3, characterized in that: The weight ratio of the layered silicate to the tetrapod-shaped zinc oxide whiskers is 7:2.

5.

6. The high temperature cooking resistant polyethylene composite film according to claim 1, characterized in that: The metallocene high-density polyethylene includes Total's product model M4707EP, the metallocene low-density polyethylene includes Exxon's product model E1018MA, the styrene block thermoplastic elastomer includes Japan's Kuraray's product model 4055, the compatibilizer includes maleic anhydride grafted polyethylene, and the layered silicate includes at least one of montmorillonite and mica flakes.

7. The high temperature cooking resistant polyethylene composite film according to claim 1, characterized in that: The antioxidant is composed of antioxidant 1010 and antioxidant 168 in a weight ratio of 1:2, and the lubricant is composed of ethylene bisstearamide and pentaerythritol stearate in a weight ratio of (2-3):

1.

8. A method for preparing a high temperature resistant cooking polyethylene composite film according to any one of claims 1 to 7, characterized in that: The preparation method of the high temperature resistant cooking polyethylene composite film comprises the following steps: The components are added into a film blowing machine in proportion, melt co-extruded, blown into a film from a film head, and then subjected to cast molding, traction cooling, trimming, winding and cutting processes to obtain the high-temperature cooking resistant polyethylene composite film.

9. The method for preparing a high temperature resistant cooking polyethylene composite film according to claim 8, characterized in that: The working condition parameters of the film blowing machine include: screw speed of 300-450 rpm, barrel temperature of 190-195° C., die head temperature of 195-200° C., and blow-up ratio of 2-2.

5.

10. Use of the high-temperature cooking-resistant polyethylene composite film according to any one of claims 1 to 7 or the high-temperature cooking-resistant polyethylene composite film prepared by the method for preparing the high-temperature cooking-resistant polyethylene composite film according to any one of claims 8 to 9 in preparing cooking packaging bags.

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