High-strength composite polyethylene air bubble film as well as preparation method and application thereof

Abstract

The invention provides a high-strength composite polyethylene air bubble film as well as a preparation method and application thereof. The composite polyethylene air bubble film comprises a high-strength polyethylene woven cloth layer, a polyethylene casting air bubble film layer and a polyethylene heat-sealing film layer which are sequentially compounded, the high-strength polyethylene woven cloth layer is prepared from the following raw materials: first high-density polyethylene, first linear low-density polyethylene, an ethylene-octylene block copolymer, a first compatilizer and a first functional aid; the polyethylene casting air bubble film layer is prepared from the following raw materials: second high-density polyethylene, second linear low-density polyethylene, metallocene linear low-density polyethylene, a first ethylene-octylene random copolymer, an organic nucleating agent, a second compatilizer and a second functional aid; the polyethylene heat-sealing film layer is prepared from the following raw materials: branched linear low-density polyethylene, metallocene polyethylene and a second ethylene-octylene random copolymer; the polyethylene heat sealing film layer is of a double-layer structure. The composite polyethylene bubble film has high strength, can be recycled and is beneficial to environmental protection.

Description

Technical Field

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

[0002] The automotive parts industry is the foundation for the rapid development of the automotive industry. With the development of globalization of the world economy and market integration, major vehicle manufacturers in the world have reformed their supply systems and implemented global production and procurement strategies, which has separated the manufacturing of automotive parts from vehicle manufacturing and faced the market independently. As a result, the demand for automotive parts packaging materials has increased sharply. These automotive parts packaging materials are directly discarded, incinerated or landfilled after use, which has caused serious harm to the environment. The environmental protection, greenness and low carbonization of various automotive components are the driving force for the development of the entire industry.

[0003] The country advocates the whole-chain governance of plastic pollution, strengthens the classification, recycling and reuse of plastic waste, plans to vigorously develop the circular economy including plastic recycling, focuses on solving prominent contradictions and problems, realizes the efficient use and recycling of plastics, and promotes high-quality economic and social development. Therefore, combined with the further strengthening of the country's plastic pollution control policy and the continuous development of the automotive parts packaging industry, it is imperative to develop high-strength and recyclable automotive parts packaging materials.

[0004] Bubble film is a kind of transparent soft packaging material commonly used at present. Its principle is to use the film to contain air to form bubbles to prevent the product from impacting and ensure that it can protect the product when it is shaken. Traditional bubble bags use linear low-density polyethylene (density 0.910-0.925g / cm 3 ), which is formed by film cutting and other preparation processes; although it is easy to process, it has a low modulus and the outermost layer is often made of polypropylene woven cloth. Due to the presence of phase interfaces between components such as polyethylene and polypropylene, the interface compatibility is relatively poor, and the physical and processing properties of polyethylene and polypropylene do not match, it is impossible to use a unified recycling process to prepare recycled materials, which makes it more difficult to recycle them again. After use, they are often directly discarded, causing serious harm to the environment. For this reason, polyethylene can be used entirely to form packaging materials to solve the above problems. However, high-density polyethylene with a single structure (density of 0.941-0.965g / cm 3 ) cannot achieve multifunctional requirements, and the compatibility between different polyethylene materials is not very high, which will directly affect the mechanical properties and service life of the material. In addition, how to highlight the performance characteristics of different polyethylene materials through modification treatment and prepare a composite polyethylene bubble film with excellent comprehensive performance is also a research difficulty. Summary of the invention

[0005] In view of this, the present invention provides a high-strength composite polyethylene bubble film and a preparation method and application thereof. The bubble film provided by the present invention has the characteristics of high strength, etc., can be recycled, is beneficial to environmental protection, and is suitable for large-scale production and promotion.

[0006] The present invention provides a high-strength composite polyethylene bubble film, comprising a high-strength polyethylene woven cloth layer, a polyethylene cast bubble film layer and a polyethylene heat-sealing film layer which are composited in sequence;

[0007] The raw materials of the high-strength polyethylene woven fabric layer include a first high-density polyethylene, a first linear low-density polyethylene, an ethylene-octene block copolymer, a first compatibilizer and a first functional additive; the high-strength polyethylene woven fabric layer uses the first high-density polyethylene as the woven fabric layer matrix; the raw materials of the polyethylene cast bubble film layer include a second high-density polyethylene, a second linear low-density polyethylene, a metallocene linear low-density polyethylene, a first ethylene-octene random copolymer, an organic nucleating agent, a second compatibilizer and a second functional additive; the polyethylene cast bubble film uses the second high-density polyethylene as the bubble film layer matrix;

[0008] The raw materials of the polyethylene heat-sealing film layer include branched linear low-density polyethylene, metallocene polyethylene and a second ethylene-octene random copolymer; the polyethylene heat-sealing film layer has a double-layer structure, and the branched linear low-density polyethylene is the main body of the heat-sealing film layer.

[0009] In some embodiments of the present invention, in the raw material of the high-density polyethylene woven cloth layer, the mass ratio of the first high-density polyethylene, the first linear low-density polyethylene and the ethylene-octene block copolymer is 100:5-10:10-20; in the raw material of the polyethylene cast bubble film layer, the mass ratio of the second high-density polyethylene, the second linear low-density polyethylene, the metallocene linear low-density polyethylene and the first ethylene-octene random copolymer is 100:10-20:15-20:5-10; in the raw material of the polyethylene heat-sealing film layer, the mass ratio of the branched linear low-density polyethylene, the metallocene polyethylene and the second ethylene-octene random copolymer is 100:10-20:20-30.

[0010] In some embodiments of the present invention, the weight average molecular weight of the ethylene-octene block copolymer is 150,000-250,000; the second linear low-density polyethylene is a branched linear low-density polyethylene with a branching degree of 14-17‰; the weight average molecular weights of the first ethylene-octene random copolymer and the second ethylene-octene random copolymer are respectively 150,000-200,000.

[0011] In some embodiments of the present invention, the first compatibilizer and the second compatibilizer are glycidyl methacrylate graft copolymer and / or maleic anhydride graft copolymer respectively; the organic nucleating agent is one or more of a sorbitol nucleating agent, a phosphate nucleating agent and a rosin-based nucleating agent.

[0012] In some embodiments of the present invention, the first functional auxiliary agent is one or more of an antioxidant, a brightener, an antistatic agent and a flame retardant; the second functional auxiliary agent is one or more of an antioxidant, a brightener, an anti-blocking agent and a lubricant.

[0013] Compared with the prior art, the embodiment of the present invention uses high-density polyethylene as the matrix, uses polyethylene materials with different molecular structures and additives and additives for modification, and regulates the rheological behavior and crystallization behavior of different layer structure components through different processing methods, and finally forms a recyclable, high-strength composite polyethylene bubble film and bubble bag. The high-strength composite polyethylene bubble film prepared by the method of the embodiment of the present invention makes full use of the regulation of the crystallization behavior and performance of polyethylene by formula design and different processing techniques, and specifically designs a high-strength and high-toughness outer woven cloth layer and a high-toughness and high-heat-sealing strength inner heat-sealing film, which can significantly improve the mechanical properties and heat-sealing strength of the bubble film, and can be applied to the field of automotive parts packaging and transportation.

[0014] The present invention provides a method for preparing the composite polyethylene bubble film as described above, comprising the following steps:

[0015] A first high-density polyethylene, a first linear low-density polyethylene, an ethylene-octene block copolymer, a first compatibilizer and a first functional additive are mixed and granulated to obtain a special material for an outer layer woven fabric; the special material for the outer layer woven fabric is formed into a preliminary cast film with a lamellar structure by a melt stretching method, and then a crystalline cast film with a core-shell structure is obtained by heat treatment, which is cut into flat yarns, and then a high-strength high-oriented flat yarn is obtained by a heat stretching method, and the flat yarns are used as warp yarns and weft yarns to prepare a woven fabric;

[0016] The second high-density polyethylene, the second linear low-density polyethylene, the metallocene linear low-density polyethylene, the first ethylene-octene random copolymer, the organic nucleating agent, the second compatibilizer and the second functional additive are mixed and granulated to obtain a special material for the middle layer cast film; the special material for the middle layer cast film is melt-extruded, and the film is cast and vacuum-adsorbed by a bubble roller to obtain a bubble film substrate;

[0017] The branched linear low-density polyethylene, the metallocene polyethylene and the second ethylene-octene random copolymer are mixed and granulated to obtain a special material for the inner layer heat-sealing film; the special material for the inner layer heat-sealing film and another branched linear low-density polyethylene are subjected to double-layer co-extrusion casting to obtain a heat-sealing film;

[0018] The woven cloth and the heat-sealing film are respectively used to cover the two surfaces of the bubble film substrate, the woven cloth is pressed against one side of the bubble film substrate to form a plurality of bubble structures, and the other side of the bubble film substrate is pressed against the branched linear low-density polyethylene of the heat-sealing film to obtain a high-strength composite polyethylene bubble film.

[0019] In some embodiments of the present invention, in the melt stretching method of the special material for the outer layer woven cloth, the drawing ratio is 20-40; the temperature of the preliminary cast film heat treatment is 100-110°C; in the flat wire hot stretching method, the flat wire width is 2-4mm, the temperature is 90-120°C, the stretching multiple is 2-3 times, and it is shaped at a temperature of 100-120°C.

[0020] In some embodiments of the present invention, in the double-layer co-extrusion casting, the processing temperature is 190-210°C, and the melt draw ratio is 3-6; the blending temperature of the granulation to obtain the special material for the middle layer cast film is 180-190°C, the processing temperature of the melt extrusion is 190-210°C, and the bubble diameter of the bubble film substrate is 8-12mm.

[0021] The present invention provides a high-strength composite polyethylene bubble bag, which is formed by the composite polyethylene bubble film described above through a bag making process. In addition, the present invention provides the use of the composite polyethylene bubble film described above in the packaging and transportation of automobile parts.

[0022] According to the preparation method described in the present invention, a high-strength composite polyethylene bubble film is obtained, and physical and chemical modifications and process conditions are effectively utilized to regulate the crystallization behavior of different polyethylene components, and different film layers with different structures and properties are designed in a targeted manner to achieve multifunctional requirements, significantly improve the comprehensive mechanical properties of the composite bubble film, and can meet the "green environmental protection and recycling" standards of automotive parts packaging, meet market requirements, and have high product application value. Compared with the existing methods, the method described in the embodiment of the present invention uses polyethylene materials to replace traditional polypropylene materials, and the prepared bubble film can be recycled. The embodiment of the present invention utilizes different formula designs, supplemented by specific processing technology, to regulate the compatibility and crystallization behavior of different components, etc., to improve the mechanical properties and functionality of the non-melting composite layer, and to achieve the organic combination of polyethylene materials with different structures and properties. The preparation method of the high-strength composite bubble film described in the present invention is simple and efficient, can solve the problem that traditional bubble bags are difficult to recycle and reuse, and provides a feasible solution for the development of industries related to plastic recycling processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following is a brief introduction to the drawings required for use in the implementation method. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 Schematic diagram of the heat sealing process of high-strength composite polyethylene bubble film. DETAILED DESCRIPTION

[0025] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the technical scheme of the present invention is now described in detail below in conjunction with specific embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0026] The present invention provides a high-strength composite polyethylene bubble film, comprising a high-strength polyethylene woven cloth layer, a polyethylene cast bubble film layer and a polyethylene heat-sealing film layer which are composited in sequence;

[0027] The raw materials of the high-strength polyethylene woven cloth layer include a first high-density polyethylene, a first linear low-density polyethylene, an ethylene-octene block copolymer, a first compatibilizer and a first functional additive; the high-strength polyethylene woven cloth layer uses the first high-density polyethylene as the woven cloth layer matrix; the raw materials of the polyethylene cast bubble film layer include a second high-density polyethylene, a second linear low-density polyethylene, a metallocene linear low-density polyethylene, a first ethylene-octene random copolymer, an organic nucleating agent, a second compatibilizer and a second functional additive; the polyethylene cast bubble film uses the second high-density polyethylene as the bubble film layer matrix; the raw materials of the polyethylene heat-sealing film layer include a branched linear low-density polyethylene, a metallocene polyethylene and a second ethylene-octene random copolymer; the polyethylene heat-sealing film layer has a double-layer structure, and uses the branched linear low-density polyethylene as the heat-sealing film layer body.

[0028] The bubble film provided by the present invention has the characteristics of high strength, etc., can be recycled, is beneficial to environmental protection, and is suitable for large-scale production and promotion.

[0029] The high-strength composite polyethylene bubble film described in the embodiment of the present invention has a high-strength polyethylene woven cloth layer as an outer layer, a polyethylene cast bubble film layer as a middle layer, and a polyethylene heat-sealing film layer as an inner layer; the outer layer is generally a sheet layer away from or not in contact with the packaging contents, and the inner layer is opposite to the outer layer, and the middle layer is between the two.

[0030] In the embodiment of the present invention, the outer layer is a high-strength polyethylene woven cloth layer, which can be called an outer layer of high-strength polyethylene woven cloth, which is a cloth woven from polyethylene flat wires, has high strength, a crystallinity of 69-74%, and a density of 150-180 g / m2 . According to the standard, the woven cloth layer is tested for tensile load, and the magnitude of the tensile load is consistent with the magnitude of the tensile strength. A rough calculation of the tensile load divided by the width and thickness can roughly give the tensile strength. The high-strength polyethylene woven cloth layer uses the first high-density polyethylene as the woven cloth layer matrix, and its raw materials include the first high-density polyethylene, the first linear low-density polyethylene, the ethylene-octene block copolymer, the first compatibilizer and the first functional additive.

[0031] In some specific embodiments, the raw material composition of the high-strength polyethylene woven cloth layer includes: 100 parts by weight of high-density polyethylene (HDPE), 5-10 parts by weight of linear low-density polyethylene (LLDPE), 10-20 parts by weight of ethylene-octene block copolymer (OBC), 1-3 parts by weight of compatibilizer, and 0.01-7 parts by weight of functional additive. To facilitate the distinction of other sheet materials, the high-density polyethylene in the high-strength polyethylene woven cloth layer is recorded as the first high-density polyethylene, the linear low-density polyethylene is recorded as the first linear low-density polyethylene, the compatibilizer is recorded as the first compatibilizer, and so on.

[0032] Furthermore, the density of the high-density polyethylene is 0.941-0.965 g / cm 3 The melt index is preferably 3.0-5.0 g / 10 min (190°C, 2.16 kg, the melt index conditions are the same below), and the weight average molecular weight can be 200,000-300,000. The linear low-density polyethylene has a structural formula of -[CH2-CH2] n -Low-density polyethylene, the preparation of which includes polymerization with ethylene as the main raw material and a small amount of α-olefins such as 1-butene, 1-octene, etc. under the action of a catalyst. The density of the linear low-density polyethylene is 0.910-0.925 g / cm 3 The melt index is preferably 2.0-4.0 g / 10 min, and the weight average molecular weight can be 150,000-200,000. The macromolecular structure of the ethylene-octene block copolymer includes an ethylene block and an octene block, and its density can be 0.870-0.920 g / cm 3 The melt index is preferably 2.0-4.0 g / 10 min, the weight average molecular weight is preferably 150,000-250,000, and the mass content of octene is preferably 20-25%.

[0033] Preferably, the first compatibilizer of the present invention is a graft copolymer with glycidyl methacrylate (GMA) or maleic anhydride (MA), and the grafting rate of GMA and MA in the graft copolymer is further 1-1.5%. Specifically, the graft copolymer is one or more of high-density polyethylene grafted with glycidyl methacrylate (HDPE-g-GMA), linear low-density polyethylene grafted with glycidyl methacrylate (LLDPE-g-GMA), ethylene-octene block copolymer grafted with glycidyl methacrylate (OBC-g-GMA), high-density polyethylene grafted with maleic anhydride (HDPE-g-MA), linear low-density polyethylene grafted with maleic anhydride (LLDPE-g-MA), and ethylene-octene block copolymer grafted with maleic anhydride (OBC-g-MA); the polymer parameters may be consistent with the above.

[0034] The first functional auxiliary agent is preferably one or more of an antioxidant, a brightener, an antistatic agent and a flame retardant, further comprising 0.1-1 parts by weight of an antioxidant, 0.04-0.1 parts by weight of a brightener, 2-4 parts by weight of an antistatic agent and 0.1-2 parts by weight of a flame retardant.

[0035] Wherein, the antioxidant includes phosphites, phenols, and amines, which can delay or inhibit the oxidation of the polymer system, and is preferably one or more of antioxidant 168, antioxidant 1010, antioxidant 1076 and antioxidant 1098; the chemical name of antioxidant 168 is tris[2.4-di-tert-butylphenyl]phosphite, the chemical name of antioxidant 1010 is: tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol, antioxidant 1076 is also known as β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and antioxidant 1098 is also known as N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine. The antistatic agent is one or more of fatty amine ethoxy ether, polyol fatty acid ester, fatty acid alkanolamide, and phosphate fatty alcohol ester antistatic agents, wherein the fatty chain length (number of carbon atoms) can be 10 to 18; the flame retardant is one or more of chlorinated paraffin, antimony trioxide, aluminum hydroxide, and magnesium hydroxide.

[0036] The brightener mainly has a cyclic conjugated system structure, including diphenylethylene, benzimidazole, benzopyrazole, benzoxazole, preferably one or more of 1,4-di(benzoxazolyl-2-yl)naphthalene, 4,4-bis(5-methyl-2-benzoxazolyl)diphenylethylene, 2,5-di(5-tert-butyl-2-benzoxazolyl)thiophene, diphenylethylene bisbenzoxazole, 1,4-di(5-methyl-2-benzoxazolyl)naphthalene.

[0037] In a preferred embodiment of the present invention, the outer layer of high-strength polyethylene woven fabric is prepared by:

[0038] First, 100 parts by weight of high-density polyethylene, 5-10 parts by weight of linear low-density polyethylene, 10-20 parts by weight of ethylene-octene block copolymer (octene content is 20-25%), 1-3 parts by weight of compatibilizer (grafting rate is 1-1.5%), 0.1-1 parts by weight of antioxidant, 0.04-0.1 parts by weight of brightener, 2-4 parts by weight of antistatic agent, 0.1-2 parts by weight of flame retardant are placed in a mixer, and can be mixed at room temperature for 20-30 minutes. After that, the mixed materials are granulated in a twin-screw extruder, the blending temperature is preferably set to 185-195° C., the die temperature is set to 170-180° C. (the blending temperature is the processing temperature, which refers to the processing temperature of the middle section of the twin-screw extruder. Generally, the die temperature is lower for cooling and extrusion), and the screw extrusion speed is 100-200 rpm. After granulation, the pellets are placed in an oven, preferably dried at 60-80° C. to obtain an outer layer of high-strength polyethylene woven cloth special material, which can be referred to as woven cloth special material.

[0039] Secondly, the outer layer polyethylene woven cloth special material is put into the casting equipment, the processing temperature is preferably set to 200-220°C, the extruder die temperature can be 190-210°C, the casting roller temperature is 90-110°C (the processing temperature refers to the processing temperature of the twin screw in the casting machine, and the machine die temperature refers to the temperature of the extrusion port (the casting film is extruded from here), and then falls on the casting roller for traction to form a film), the draft ratio is preferably 20-40, further 25-38 (the traction ratio is the ratio of the traction speed of the extruded film to the extrusion speed from the film port. For the film, the larger the traction ratio, the larger the corresponding stretch multiple), the distance between the extruder die and the casting roller can be 200-300mm, and after cooling, it is cut and rolled up to obtain a preliminary cast film with a lamellar structure. Then, the preliminary cast film is preferably annealed at 100-110°C, the crystallinity is improved by recrystallization, and a highly crystalline core-shell structure is formed, and the film is cut into flat yarns after cooling again, and the width of the flat yarn is 2-4mm; then, it is preferably hot stretched at 90-120°C, the stretching ratio is 2-3 times, and it is shaped at 100-120°C to obtain warp and weft yarns with high strength and high orientation, and finally it is woven by a circular loom, and the final woven cloth is obtained by slitting and winding, and the density of the woven cloth is 150-180g / m 2 .

[0040] The preferred embodiment of the present invention first prepares a cast film by a melt stretching method with a high traction ratio, and induces crystallization by stress to obtain a highly oriented, twisted row-shaped lamellar structure; then, heat treatment is performed near the crystallization temperature to improve the crystallinity, and the newly grown crystals are formed by attaching to the lamellar crystals, thereby obtaining a core-shell structure with perfect crystallization; then, a hot stretching method is used to further improve the degree of directional arrangement of the crystals, and a high-strength, high-toughness, and high-oriented flat wire is obtained to prepare a woven cloth. Among them, the high-density polyethylene is toughened and modified by using linear low-density polyethylene and ethylene-octene block copolymers, and the linear low-density polyethylene and ethylene-octene block copolymers are used to hinder the crystallization rate of high-density polyethylene. With the stress-induced effect during the two stretching processes, the lattice structure can be changed, and the orientation degree along the stretching direction can be increased, and the longitudinal tensile strength of the flat wire can be further increased. The compatibility is improved by using a compatibilizer to form a eutectic structure. The improvement of compatibility is conducive to the uniform dispersion of antioxidants, etc., and is conducive to improving the service life of the woven cloth. The embodiment of the present invention uses the prepared high-strength woven cloth as the outer layer of the composite bubble film, thereby improving the strength of the composite bubble bag.

[0041] In addition, the middle layer of the polyethylene composite bubble film described in the embodiment of the present invention is a polyethylene cast bubble film layer, which is mainly a polyethylene raw material cast film with a plurality of bubble holes; the crystallinity of the middle bubble film layer can be 36-40%. The polyethylene cast bubble film uses the second high-density polyethylene as the bubble film layer matrix, and its raw materials include the second high-density polyethylene, the second linear low-density polyethylene, the metallocene linear low-density polyethylene, the first ethylene-octene random copolymer, the organic nucleating agent, the second compatibilizer and the second functional additive.

[0042] In some specific embodiments, the raw material composition of the middle layer polyethylene cast bubble film layer includes: 100 parts by weight of high-density polyethylene (HDPE), 10-20 parts by weight of highly branched linear low-density polyethylene (highly branched LLDPE), 10-20 parts by weight of metallocene linear low-density polyethylene, 5-10 parts by weight of a first ethylene-octene random copolymer, 0.1-0.5 parts by weight of an organic nucleating agent, 1-3 parts by weight of a second compatibilizer, and 0.01-3 parts by weight of a second functional additive.

[0043] Furthermore, the second high-density polyethylene parameters may be the same as or different from the first high-density polyethylene parameters; the density of the second high-density polyethylene may be 0.941-0.965 g / cm 3 , melt index is 3.0-5.0g / 10min, weight average molecular weight is 200,000-300,000. In the embodiment of the present invention, a highly branched linear low-density polyethylene is used as the second linear low-density polyethylene, and its density can be 0.910-0.925g / cm 3, the melt index is preferably 2.0-3.0g / 10min, the weight average molecular weight is preferably 200,000-250,000, and the degree of branching is 14-17‰. The degree of branching refers to the number and length of branch chains on the polymer main chain, that is, the complexity of the polymer molecular chain. For highly branched linear low-density polyethylene, its degree of branching is usually high, which means that its molecular chain contains more short branches.

[0044] In addition, the present invention also uses metallocene linear low-density polyethylene and ethylene-octene random copolymer. The metallocene linear low-density polyethylene may have a melt index of 2-5 g / min and a density of 0.910-0.927 g / cm 3 The weight average molecular weight is 150,000-200,000. The density of the ethylene-octene random copolymer can be 0.870-0.920 g / cm 3 The melt index is 2.0-5.0g / 10min, the weight average molecular weight is 150,000-200,000, and the mass content of octene is 20-25%.

[0045] The embodiment of the present invention uses high-density polyethylene as the middle layer bubble film matrix, and uses linear low-density polyethylene and metallocene polyethylene to improve its mechanical properties; uses a compatibilizer to improve compatibility to form a eutectic structure, which further improves the mechanical properties of the bubble film while also improving the dispersion of processing aids such as antioxidants in the polyethylene, improving antioxidant properties, etc. At the same time, the embodiment of the present invention uses an organic nucleating agent to change the crystallization behavior of polyethylene, improve nucleation efficiency, reduce the size of spherulites in the film, and effectively improve the mechanical properties of the bubble film.

[0046] The proportion of the compatibilizer can be 1-3 parts by weight, preferably 1.5-3 parts by weight. The compatibilizer is preferably a graft copolymer with glycidyl methacrylate (GMA) or maleic anhydride (MA), and the grafting rate of GMA and MA in the graft copolymer is 1-1.5%. Specifically, the graft copolymer is one or more of high-density polyethylene grafted with glycidyl methacrylate (HDPE-g-GMA), linear low-density polyethylene grafted with glycidyl methacrylate (LLDPE-g-GMA), high-density polyethylene grafted with maleic anhydride (HDPE-g-MA), and linear low-density polyethylene grafted with maleic anhydride (LLDPE-g-MA). In addition, the first compatibilizer and the second compatibilizer can be the same or different.

[0047] Moreover, the organic nucleating agent ratio can be 0.1-0.5 parts by weight, preferably 0.2-0.4 parts. The organic nucleating agent type is preferably one or more of sorbitol nucleating agents, phosphate nucleating agents and rosin-based nucleating agents. Among them, the sorbitol nucleating agent can be one or more of dibenzylidene sorbitol (DBS), p-dimethyldibenzylidene sorbitol (MDBS), p-methylmethylene sorbitol (MMBS), di(p-methylbenzylidene) allyl sorbitol (BMBAS), di(3,4-dimethyldibenzylidene) sorbitol (DMDBS), di(p-ethyl)benzylidene sorbitol (EDBS), di(p-chlorosubstituted benzyl) sorbitol (PCIDBS), di(trimethylbenzylidene) sorbitol (TMDBS), di(tetrahydronaphthalene methylene) sorbitol (DTNHS).

[0048] The phosphate nucleating agent may specifically be one or more of bis(2,4-di-tert-butylphenoxy) sodium phosphate, bis(2-tert-butyl, 4-methylphenoxy) sodium phosphate, 2,2'-methylene-bis(4,6-di-tert-butylphenoxy) sodium phosphate, and 2,2'-methylene-bis(4-methyl-6-tert-butylphenoxy) sodium phosphate. The rosin-based nucleating agent is preferably one or more of rosin acid amide, sodium dehydroabietic acid, magnesium dehydroabietic acid, potassium dehydroabietic acid, calcium rosinate, zinc rosinate, and sodium rosinate.

[0049] In some embodiments of the present invention, the second functional auxiliary agent is one or more of an antioxidant, a whitening agent, an anti-blocking agent and a lubricant, wherein the types of the antioxidant and the whitening agent are as described above, and may be the same or different. The antioxidant ratio may be 0.1-1 parts by weight, such as 0.1 parts, 0.5 parts, 0.6 parts, 1 parts, etc. The antioxidant is preferably one or more of antioxidant 168, antioxidant 1010, antioxidant 1076 and antioxidant 1098. The whitening agent may be 0.04-0.1 parts by weight; the whitening agent is preferably a benzoxazole, further one or more of 4,4-bis(5-methyl-2-benzoxazolyl)diphenylethylene, 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene, distyrylbisbenzoxazole, 1,4-bis(benzoxazolyl-2-yl)naphthalene, and 1,4-bis(5-methyl-2-benzoxazolyl)naphthalene.

[0050] In addition, the second functional agent also includes: 0.1-0.4 parts by weight of an opening agent; 0.01-0.2 parts by weight of a lubricant. The opening agent can improve the processing performance and fluidity of the resin, and can allow air to enter during film processing; it can be divided into organic opening agents and inorganic opening agents. The opening agent described in the present invention is preferably one or more of calcium sulfate, calcium hydrogen phosphate, barium sulfate, silicon dioxide and diatomaceous earth, and the particle size of these inorganic opening agents is generally 50-200nm. Among them, the silica opening agent is usually artificially synthesized amorphous silicon dioxide with high performance. The lubricant mainly utilizes the migration characteristics of the substance, and can migrate to the surface of the film in the later stage of the film processing process to form a covering layer, which can play a role in lubrication, etc.; the lubricant is preferably one or more of the migration-type primary amide lubricants such as para-behenamide, oleamide, stearamide, erucamide and isostearamide.

[0051] In a preferred embodiment of the present invention, the preparation of the middle bubble film includes:

[0052] First, 100 parts by weight of high-density polyethylene, 10-20 parts by weight of highly branched linear low-density polyethylene (branching degree is 14-17‰), 10-20 parts by weight of metallocene linear low-density polyethylene, 5-10 parts by weight of ethylene-octene random copolymer (octene mass content is 20-25%), then 0.1-0.5 parts by weight of organic nucleating agent, 1-3 parts by weight of compatibilizer (grafting rate is 1-1.5%), 0.1-1 parts by weight of antioxidant, 0.04-0.1 parts by weight of brightener, 0.1-0.4 parts by weight of anti-blocking agent, 0.01-0.2 parts by weight of lubricant are placed in a mixer, mixed at room temperature for 20-30 minutes, and the rotation speed can be set to 200-400 rpm. Afterwards, the mixed material is granulated in a twin-screw extruder, the blending temperature is preferably set to 180-190°C, the die temperature is set to 170-180°C, and the screw extrusion speed is 100-200 rpm. After granulation, it is placed in an oven and dried at 50-60°C to obtain a special material for the middle layer polyethylene cast film.

[0053] The obtained special material for the middle layer polyethylene cast film is put into the bubble film machine, the processing temperature is preferably 190-210°C, the rotation speed can be set to 300-500 rpm, and the extruded polyethylene raw material is cast and vacuum adsorbed by the bubble roller to form a bubble film substrate. Among them, the vacuum degree of the bubble roller is preferably 0.03-0.05MPa; the bubble diameter is 8-12mm, and the bubble height is 3-7mm. The bubble distribution refers to the size, shape and arrangement of the bubbles in the bubble film on the film. The density of the bubble film refers to the mass contained in the bubble film per unit volume; the size generally refers to the diameter and height of the bubble. The bubble distribution described in the present invention adopts a general uniform distribution, which mainly limits the size of the bubble, and is generally obtained by the corresponding vacuum roller design.

[0054] The embodiment of the present invention uses high-density polyethylene as the bubble film matrix, uses linear low-density polyethylene and metallocene polyethylene to improve its mechanical properties, and uses a compatibilizer to improve compatibility to form a eutectic structure. While further improving the mechanical properties of the bubble film, it also improves the dispersion of processing aids such as antioxidants in the polyethylene, improves antioxidant properties, etc. At the same time, the crystallization behavior of polyethylene is changed mainly through an organic nucleating agent, the nucleation efficiency is improved, the size of spherulites in the film is reduced, and the mechanical properties of the bubble film are improved.

[0055] The high-strength composite polyethylene bubble film of the embodiment of the present invention comprises an inner polyethylene heat-sealing film layer, which is composited on the other surface of the polyethylene bubble film layer, is a heat-sealing film layer with a double-layer structure, and uses branched linear low-density polyethylene as the main body of the heat-sealing film layer.

[0056] Specifically, the raw material of the inner polyethylene heat-sealing film layer first includes 100 parts by weight of highly branched linear low-density polyethylene (highly branched LLDPE). The density of the highly branched linear low-density polyethylene may be 0.910-0.925 g / cm 3 , melt index is 2.0-3.0g / 10min, weight average molecular weight is 200,000-250,000, and degree of branching is 14-17‰; the specific values ​​are the same or different from those described above.

[0057] The raw material of the polyethylene heat-sealing film layer in the embodiment of the present invention includes metallocene polyethylene (mPE), 10-20 parts by weight; the metallocene polyethylene is metallocene linear low-density polyethylene (mLLDPE) and / or metallocene ultra-low-density polyethylene (mVLDPE). The melt index of the metallocene linear low-density polyethylene is preferably 1-2 g / min, and the density can be 0.910-0.927 g / cm 3 The weight average molecular weight is preferably 150,000-200,000. The melt index of the metallocene ultra-low density polyethylene is preferably 1-2 g / min, and the density is 0.900-0.910 g / cm 3, the weight average molecular weight is 150,000-200,000.

[0058] The raw material of the polyethylene heat-sealing film layer includes ethylene-octene random copolymer, 20-30 parts by weight. The density of the ethylene-octene random copolymer is preferably 0.870-0.920 g / cm 3 , a melt index of 2.0-5.0 g / 10 min, a weight average molecular weight of 150,000-200,000, and a mass content of octene of 20-25%. In addition, the specific parameter values ​​of the first ethylene-octene random copolymer and the second ethylene-octene random copolymer can be the same or different, and can be within the performance parameter range.

[0059] The preparation of the inner polyethylene heat-sealing film according to the embodiment of the present invention further comprises:

[0060] First, 100 parts by weight of highly branched linear low-density polyethylene (melt index of 2.0-3.0 g / 10 min, weight average molecular weight of 200,000-250,000, and degree of branching of 14-17‰), 10-20 parts by weight of metallocene polyethylene (melt index of 1.0-2.0 g / 10 min, weight average molecular weight of 150,000-200,000), and 20-30 parts by weight of ethylene-octene random copolymer (melt index of 2.0-5.0 g / 10 min, weight average molecular weight of 150,000-200,000, wherein the mass content of octene is 20-25%) are placed in a mixer, mixed at room temperature for 20-30 min, the rotation speed is set to 200-400 rpm, and then the mixed materials are granulated in a twin-screw extruder, the blending temperature can be set to 170-180° C., the die head temperature is set to 160-170° C., and the screw extrusion speed is 100-200 rpm. After granulation, the product is dried in an oven at 50-60°C to obtain a special material for the inner layer polyethylene heat-sealing film.

[0061] The above-mentioned highly branched linear low-density polyethylene and the inner layer polyethylene heat-sealing film special material are respectively put into different hoppers of the co-extrusion casting equipment, the processing temperature is preferably set to 190-210°C, the casting die temperature is 185-200°C, the casting roller temperature is 80-90°C, and the cooling roller temperature is 25-35°C; the melt draw ratio is preferably 3-6, and then cutting and winding are carried out to obtain the inner layer polyethylene cast heat-sealing film.

[0062] The embodiment of the present invention uses linear low-density polyethylene with a high degree of branching as the main body of the inner heat-sealing film to prepare a cast film with a low draft ratio, increase the amorphous ratio at a lower heat-sealing temperature, and allow more molecules to participate in the formation of the heat-sealing layer, which can effectively reduce the heat-sealing temperature (the normal heat-sealing temperature of high-density polyethylene is above 110 degrees, and the present application is lower than this temperature, such as 95-100 degrees C), and improve the heat-sealing strength. For bubble films made entirely of polyethylene materials, lowering the heat-sealing temperature can reduce the impact of the outer film becoming thinner or melting at the heat-sealing location due to heat sealing, thereby improving the overall performance of the bubble film.

[0063] Furthermore, the embodiments of the present invention utilize metallocene polyethylene and ethylene-octene random copolymer to further reduce the heat-sealing temperature and significantly improve the heat-sealing strength, thereby preparing a double-layer polyethylene heat-sealing film layer with low heat-sealing temperature and high heat-sealing strength.

[0064] Accordingly, the present invention provides a method for preparing the composite polyethylene bubble film as described above, comprising:

[0065] The outer woven fabric layer, the middle polyethylene bubble film substrate layer, and the inner heat-sealing film layer are formed according to the above-mentioned operations, and there is no order limit for the formation of the three layer structures;

[0066] The woven cloth and the heat-sealing film are respectively used to cover the two surfaces of the polyethylene bubble film substrate, the woven cloth and one side of the polyethylene bubble film substrate are pressed together to form a plurality of bubble structures, and the other side of the polyethylene bubble film substrate branched linear low-density polyethylene is pressed together with the heat-sealing film to obtain a high-strength composite polyethylene bubble film.

[0067] In some specific embodiments of the present invention, after the bubble film substrate is stably formed, the prepared outer layer of high-strength polyethylene woven cloth and inner layer of polyethylene heat-sealing film are introduced into the machine through traction rollers to be compounded with the bubble film substrate. The outer layer of high-strength polyethylene woven cloth is compounded with the bubble film substrate at the bubble roller, that is, while forming the bubble film substrate, it is pressed together with the outer layer of high-strength polyethylene woven cloth, and the compounding temperature is 90-110°C, and the compounding pressure is 0.2-0.4MPa. Then, the side of the bubble film substrate where the bubble is formed is pressed together with the linear low-density polyethylene layer of the inner layer of polyethylene heat-sealing film, and the compounding temperature is 90-95°C. Finally, after trimming and winding, a high-strength composite polyethylene bubble film is obtained; the compounding process is as follows Figure 1 As shown, A is the outer woven fabric layer; B is the middle polyethylene bubble film; and C is the inner heat-sealed film.

[0068] The present invention also provides a high-strength composite polyethylene bubble bag, which is formed by the composite polyethylene bubble film described above through a bag making process. Specifically, the rolled composite polyethylene bubble film can be introduced into a bag making machine, and the high-strength composite polyethylene bubble bag can be obtained through the steps of cutting, bending, hot pressing and edge sealing; preferably, the hot pressing temperature is 95-100°C.

[0069] In the embodiment of the present invention, a tensile load test is performed on the high-strength and high-oriented woven fabric described therein: according to the relevant provisions of the standard "GB / T 8946-2013 General Technical Requirements for Plastic Woven Bags", a tensile load test is performed on the prepared high-strength and high-oriented woven fabric, the spline width is 50 mm, the test speed is 200 mm / min, 5 groups are tested in parallel, and the test results are averaged.

[0070] The embodiment of the present invention performs performance evaluation on the composite polyethylene bubble film, including crystallinity test, tensile test, heat sealing strength, etc. (tensile strength and elongation at break should be considered simultaneously when considering strength).

[0071] Crystallinity test: Take about 5 mg of sample from each layer of special material, use DSC differential scanning calorimeter to determine its crystallization and melting behavior, use "rise-fall" mode under nitrogen atmosphere, scan in the temperature range of 20-190℃ at a heating and cooling rate of 10℃ / min, and calculate the crystallinity of different prepared sheets according to the known calculation formula. Using differential scanning calorimetry to test and calculate crystallinity is the most common method. Crystallinity refers to the degree to which polyethylene molecules exist in a crystalline form in the solid state, that is, the proportion of crystalline regions in polyethylene. The non-crystalline region is a disordered non-crystalline region, while the crystalline region is an ordered crystalline region. The size of the crystallinity depends on the content of the crystalline region and is an important parameter to describe the physical structure characteristics of polyethylene.

[0072] Tensile test: According to the relevant provisions of the standard "QB1259-1991-Polyethylene Air Cushion Film", the prepared high-strength composite polyethylene bubble film was subjected to a tensile test to test the tensile strength and elongation at break. Five groups were tested in parallel and the test results were averaged.

[0073] Heat seal strength: The heat seal strength of the bubble bag was measured according to the standard "YBB00122003-2015 Heat seal strength determination method". The sample was heat sealed on a heat sealer, and then 10 samples with a width of 15 mm were cut in a direction perpendicular to the heat seal position. The unfolded length was ensured to be greater than 100 mm. The heat seal strength was then measured using a tensile testing machine at a test speed of 300 mm / min. The test results were averaged.

[0074] In summary, in the preparation method described in the embodiment of the present invention, the main body is all polyethylene material, and the prepared bubble film and bubble bag can be recycled. The embodiment of the present invention utilizes different formula designs, supplemented by specific processing technology, to regulate the compatibility and crystallization behavior of different components, etc., to improve the mechanical properties and functionality of the non-melting composite layer, to achieve the organic combination of polyethylene materials with different structures and properties, and to form a polyethylene composite bubble film with good comprehensive performance, which can be applied to the fields of automobile parts packaging and transportation. The preparation method of the composite bubble film described in the present invention is simple, has high production efficiency, and can also solve the problem that traditional bubble films are difficult to recycle and reuse.

[0075] In order to better illustrate the present invention, the following examples are further illustrated. In the examples, all raw reagents and materials are commercially available, and the experimental methods without specific experimental conditions are conventional methods and conditions well known in the art.

[0076] Example 1

[0077] Outer layer high strength polyethylene woven fabric preparation:

[0078] First, 100 parts by weight of high-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 200,000, 5 parts by weight of linear low-density polyethylene with a melt index of 2.0-4.0 g / 10 min and a weight-average molecular weight of 150,000, 10 parts by weight of ethylene-octene block copolymer with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000 (the mass content of octene is 20%), 1 part by weight of high-density polyethylene grafted with glycidyl methacrylate (grafting rate is 1%), 0.1 parts by weight of antioxidant 168, 0.04 parts by weight of 1,4-di(benzoxazolyl-2-yl)naphthalene, 2 parts by weight of fatty amine ethoxy ether (fat chain length is 10), and 0.1 parts by weight of chlorinated paraffin are placed in a blender and mixed at room temperature for 20 minutes. Afterwards, the mixed material was granulated in a twin-screw extruder, the blending temperature was set at 185°C, the die temperature was set at 170°C, and the screw extrusion speed was 100 rpm. After granulation, it was placed in an oven and dried at 60°C to obtain a special material for the outer layer of high-strength polyethylene woven cloth.

[0079] Put the special material for the outer layer of polyethylene woven cloth into the casting equipment, set the processing temperature to 200℃, the extruder die temperature to 190℃, the casting roller temperature to 90℃, the draft ratio to 20, the distance between the extruder die and the casting roller to 200mm, and cut and roll it after cooling to obtain a preliminary cast film with a lamellar structure. Then anneal the preliminary cast film at 100℃ for 1h, recrystallize it to improve the crystallinity, and form a highly crystalline core-shell structure. After cooling again, cut it into flat wires with a width of 2mm, and then heat stretch it at 90℃ with a stretching multiple of 2 times, and shape it at 100℃ to obtain the required warp and weft wires with high strength and high orientation. Finally, weave it through a circular loom, and obtain the final woven cloth by slitting and rolling. The density of the woven cloth is 150g / m 2 After testing, the tensile load of the woven fabric is 625N / 50mm.

[0080] Preparation of inner polyethylene heat-sealing film:

[0081] First, take 100 parts by weight of highly branched linear low-density polyethylene (melt index of 2.0 g / 10 min, weight average molecular weight of 200,000, and degree of branching of 14‰), 10 parts by weight of metallocene linear low-density polyethylene (melt index of 1.0 g / 10 min, weight average molecular weight of 150,000), and 20 parts by weight of ethylene-octene random copolymer (melt index of 2.0 g / 10 min, weight average molecular weight of 150,000, wherein the mass content of octene is 20%), place in a blender, mix at room temperature for 20 min, and set the speed to 200 rpm. Afterwards, granulate the mixed materials in a twin-screw extruder, set the blending temperature to 170°C, the die head temperature to 160°C, and the screw extrusion speed to 100 rpm. After granulation, use an oven to dry at 50°C to obtain a special material for inner polyethylene heat-sealing film.

[0082] The above-mentioned highly branched linear low-density polyethylene and the inner layer polyethylene heat-sealing film special material are respectively put into different hoppers of the co-extrusion casting equipment, the processing temperature is set to 190°C, the casting die temperature is 185°C, the casting roller temperature is 80°C, the cooling roller temperature is 25°C, the melt stretching ratio is 3, and then cutting and winding are carried out to obtain the inner layer polyethylene cast heat-sealing film.

[0083] Preparation of middle bubble film:

[0084] First, take 100 parts by weight of high-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 200,000, 10 parts by weight of highly branched linear low-density polyethylene (branching degree of 14‰) with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 200,000, 10 parts by weight of metallocene linear low-density polyethylene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000, 5 parts by weight of ethylene-octane with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000 octene random copolymer (octene content is 20%); then take 0.1 weight part of dibenzylidene sorbitol, 1 weight part of high-density polyethylene grafted methacrylate glycidyl ester (grafting rate is 1%), 0.1 weight part of antioxidant 168, 0.04 weight part of 4,4-bis (5-methyl-2-benzoxazolyl) diphenylethylene, 0.1 weight part of calcium sulfate, 0.01 weight part of behenic acid amide and place them in a mixer, mix at room temperature for 20 minutes, and set the speed to 200 rpm. After that, the mixed materials are granulated in a twin-screw extruder, the blending temperature is set to 180°C, the die temperature is set to 170°C, and the screw extrusion speed is 100 rpm. After granulation, use an oven to dry at 50°C to obtain a special material for middle-layer polyethylene cast film.

[0085] The obtained middle layer polyethylene cast film special material is put into the bubble film machine, the processing temperature is 190°C, the rotation speed is set to 300 rpm, and the extruded polyethylene raw material is cast and vacuum adsorbed by the bubble roller to form a bubble film substrate; the vacuum degree of the bubble roller is 0.04MPa, the bubble diameter is 8mm, and the bubble height is 3mm.

[0086] Preparation of bubble bags:

[0087] After the bubble film substrate is stably formed, the prepared outer layer of high-strength polyethylene woven cloth and the inner layer of polyethylene heat-sealing film are introduced into the machine through the traction roller and compounded with the bubble film substrate. The outer layer of high-strength polyethylene woven cloth is compounded with the bubble film substrate at the bubble roller, that is, while forming the bubble film, it is pressed together with the outer layer of high-strength polyethylene woven cloth, the compounding temperature is 90°C, and the compounding pressure is 0.2MPa. Then, the side of the bubble film where the bubble is formed is pressed together with the linear low-density polyethylene layer of the inner layer of polyethylene heat-sealing film, the compounding temperature is 90°C, and then after trimming and winding, a high-strength composite polyethylene bubble film is obtained. Finally, the rolled composite polyethylene bubble film is introduced into the bag making machine, and after cutting, bending, hot pressing and sealing steps, a high-strength composite polyethylene bubble bag is obtained, and the hot pressing temperature is 95°C.

[0088] After testing, the composite polyethylene bubble film described in this embodiment has a tensile strength of 39.2 MPa, an elongation at break of 337.5%, and a heat sealing strength of 18.2 N / 15 mm; the crystallinity of each layer is shown in Table 1.

[0089] Example 2

[0090] Outer layer high strength polyethylene woven fabric preparation:

[0091] First, take 100 parts by weight of high-density polyethylene with a melt index of 3.5 g / 10 min and a weight-average molecular weight of 220,000, 6 parts by weight of linear low-density polyethylene with a melt index of 2.5 g / 10 min and a weight-average molecular weight of 160,000, 12 parts by weight of ethylene-octene block copolymer with a melt index of 2.5 g / 10 min and a weight-average molecular weight of 180,000 (the mass content of octene is 21%), then take 1.5 parts by weight of linear low-density polyethylene grafted with glycidyl methacrylate (grafting rate is 1.1%), 0.3 parts by weight of antioxidant 1010, 0.06 parts by weight of 4,4-bis(5-methyl-2-benzoxazolyl)stilbene, 2.5 parts by weight of polyol fatty acid ester (total fatty chain length is 12) and 0.5 parts by weight of antimony trioxide, place them in a blender and mix them at room temperature for 22 minutes. Afterwards, the mixed material was granulated in a twin-screw extruder, the blending temperature was set at 188°C, the die temperature was set at 172°C, and the screw extrusion speed was 125 rpm. After granulation, it was dried in an oven at 65°C to obtain a special material for the outer layer of high-strength polyethylene woven cloth.

[0092] The special material for the outer layer of polyethylene woven cloth is put into the casting equipment, the processing temperature is set to 205℃, the extruder die temperature is 195℃, the casting roller temperature is 95℃, the draft ratio is 25, the distance between the extruder die and the casting roller is 250mm, and it is cut and rolled after cooling to obtain a preliminary cast film with a lamellar structure. Then the preliminary cast film is annealed at 102℃ for 1.2h, recrystallized to improve the crystallinity, and form a highly crystalline core-shell structure. After cooling again, it is cut into flat wires with a width of 2.5mm. It is hot stretched at 99℃ with a stretching ratio of 2.2 times, and shaped at 105℃ to obtain the required warp and weft wires with high strength and high orientation. Finally, it is woven by a circular loom, and the final woven cloth is obtained by slitting and rolling. The density of the woven cloth is 157g / m 2 After testing, the tensile load of the woven fabric is 687N / 50mm.

[0093] Preparation of inner polyethylene heat-sealing film:

[0094] First, take 100 parts by weight of highly branched linear low-density polyethylene (melt index of 2.2g / 10min, weight average molecular weight of 220,000, and degree of branching of 15‰), 12 parts by weight of metallocene linear low-density polyethylene (melt index of 1.2g / 10min, weight average molecular weight of 160,000), and 22 parts by weight of ethylene-octene random copolymer (melt index of 2.5g / 10min, weight average molecular weight of 160,000, wherein the mass content of octene is 21%), place in a blender, mix at room temperature for 22min, and set the speed to 250 rev / min. Afterwards, granulate the mixed materials in a twin-screw extruder, set the blending temperature to 172°C, the die temperature to 162°C, and the screw extrusion speed to 125 rev / min. After granulation, use an oven to dry at 52°C to obtain a special material for inner polyethylene heat-sealing film.

[0095] The above-mentioned highly branched linear low-density polyethylene and the inner layer polyethylene heat-sealing film special material are respectively put into different hoppers of the co-extrusion casting equipment, the processing temperature is set to 195°C, the casting die temperature is 188°C, the casting roller temperature is 82°C, the cooling roller temperature is 27°C, the melt draw ratio is 3.8, and then cutting and winding are carried out to obtain the inner layer polyethylene cast heat-sealing film.

[0096] Preparation of middle bubble film:

[0097] First, 100 parts by weight of high-density polyethylene with a melt index of 3.5 g / 10 min and a weight-average molecular weight of 220,000, 12 parts by weight of highly branched linear low-density polyethylene (branching degree of 15‰) with a melt index of 2.2 g / 10 min and a weight-average molecular weight of 210,000, 12 parts by weight of metallocene linear low-density polyethylene with a melt index of 2.9 g / 10 min and a weight-average molecular weight of 160,000, 6 parts by weight of ethylene-octene random copolymer ( The mass content of octene is 21%), and then 0.2 parts by weight of di(tetrahydronaphthalene methylene) sorbitol, 1.5 parts by weight of linear low-density polyethylene grafted methacrylate glycidyl ester (grafting rate is 1.1%), 0.3 parts by weight of antioxidant 1010, 0.06 parts by weight of 2,5-di(5-tert-butyl-2-benzoxazolyl)thiophene, 0.19 parts by weight of calcium hydrogen phosphate, 0.05 parts by weight of oleic acid amide, placed in a blender, mixed at room temperature for 22 minutes, and the speed was set to 250 rpm. After that, the mixed materials were granulated in a twin-screw extruder, the blending temperature was set to 182°C, the die temperature was set to 172°C, and the screw extrusion speed was 125 rpm. After granulation, it was dried in an oven at 52°C to obtain a special material for the middle layer polyethylene cast film.

[0098] The obtained middle layer polyethylene cast film special material is put into the bubble film machine, the processing temperature is 195°C, the rotation speed is set to 350 rpm, and the extruded polyethylene is cast and vacuum adsorbed by the bubble roller to form a middle layer bubble film; the vacuum degree of the bubble roller is 0.04MPa, the bubble diameter is 9mm, and the bubble height is 4mm.

[0099] Preparation of bubble bags:

[0100] After the bubble film is stably formed, the prepared outer layer of high-strength polyethylene woven cloth and the inner layer of polyethylene heat-sealing film are introduced into the machine through the traction roller to be compounded with the bubble film. The outer layer of high-strength polyethylene woven cloth is compounded with the bubble film at the bubble roller, that is, while forming the bubble film, it is pressed together with the outer layer of high-strength polyethylene woven cloth, the compounding temperature is 95°C, and the compounding pressure is 0.25MPa. Next, the side of the bubble film that forms the bubble is pressed together with the linear low-density polyethylene layer of the inner layer of polyethylene heat-sealing film, and the compounding temperature is 91°C; then after trimming and rolling, a high-strength composite polyethylene bubble film is obtained. Finally, the rolled composite polyethylene bubble film is introduced into the bag making machine, and after cutting, bending, hot pressing and sealing steps, a high-strength composite polyethylene bubble bag is obtained, and the hot pressing temperature is 96°C. After testing, the tensile strength of the polyethylene bubble film described in this embodiment is 42.4MPa, the elongation at break is 277.9%, and the heat sealing strength is 19.5N / 15mm; the crystallinity of each layer is shown in Table 1.

[0101] Example 3

[0102] Outer layer high strength polyethylene woven fabric preparation:

[0103] First, take 100 parts by weight of high-density polyethylene with a melt index of 4.0 g / 10 min and a weight-average molecular weight of 250,000, 7 parts by weight of linear low-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 175,000, 15 parts by weight of ethylene-octene block copolymer with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 200,000 (the mass content of octene is 22%), then take 1 part by weight of high-density polyethylene grafted with glycidyl methacrylate (grafting rate is 1.2%), 1 part by weight of linear low-density polyethylene grafted with glycidyl methacrylate (grafting rate is 1.2%), 0.5 parts by weight of antioxidant 176, 0.07 parts by weight of 2,5-di(5-tert-butyl-2-benzoxazolyl)thiophene, 3 parts by weight of fatty acid alkanolamide (fat chain length is 14), and 1 part by weight of aluminum hydroxide, place them in a blender, and mix them at room temperature for 25 minutes. The mixed material was then pelletized in a twin-screw extruder, with the blending temperature set at 190°C, the die temperature set at 175°C, and the screw extrusion speed set at 150 rpm. After pelletization, the material was dried in an oven at 70°C to obtain a special material for the outer layer of high-strength polyethylene woven fabric.

[0104] The special material for the outer layer of polyethylene woven cloth is put into the casting equipment, the processing temperature is set to 210℃, the extruder die temperature is 200℃, the casting roller temperature is 100℃, the draft ratio is 30, the distance between the extruder die and the casting roller is 250mm, and it is cut and rolled after cooling to obtain a preliminary cast film with a lamellar structure. Then the preliminary cast film is annealed at 105℃ for 1.5h, recrystallized to improve the crystallinity, and form a highly crystalline core-shell structure. After cooling again, it is cut into flat wires with a width of 3mm. It is hot stretched at 108℃ with a stretching multiple of 2.5 times, and shaped at 110℃ to obtain the required warp and weft wires with high strength and high orientation. Finally, it is woven by a circular loom, and the final woven cloth is obtained by slitting and rolling. The density of the woven cloth is 164g / m 2 After testing, the tensile load of the woven fabric is 750N / 50mm.

[0105] Preparation of inner polyethylene heat-sealing film:

[0106] First, take 100 parts by weight of highly branched linear low-density polyethylene (melt index is 2.5g / 10min, weight average molecular weight is 230,000, and branching degree is 15.5‰), 15 parts by weight of metallocene ultra-low density polyethylene (melt index is 1.5g / 10min, weight average molecular weight is 170,000) and 25 parts by weight of ethylene-octene random copolymer (melt index is 3.2g / 10min, weight average molecular weight is 180,000, and the mass content of octene is 23%), place in a blender, mix at room temperature for 25min, and set the speed to 300 rev / min. Then, granulate the mixed materials in a twin-screw extruder, set the blending temperature to 175°C, the die head temperature to 165°C, and the screw extrusion speed to 150 rev / min. After granulation, use an oven to dry at 55°C to obtain a special material for inner polyethylene heat-sealing film.

[0107] The above-mentioned highly branched linear low-density polyethylene and the inner layer polyethylene heat-sealing film special material are respectively put into different hoppers of the co-extrusion casting equipment, the processing temperature is set to 200°C, the casting die temperature is 191°C, the casting roller temperature is 85°C, the cooling roller temperature is 30°C, the melt draw ratio is 4.6, and then cutting and winding are carried out to obtain the inner layer polyethylene cast heat-sealing film.

[0108] Preparation of middle bubble film:

[0109] First, take 100 parts by weight of high-density polyethylene with a melt index of 4.0 g / 10 min and a weight-average molecular weight of 250,000, 15 parts by weight of highly branched linear low-density polyethylene with a melt index of 2.5 g / 10 min and a weight-average molecular weight of 230,000 (branching degree is 15.5‰), 15 parts by weight of metallocene linear low-density polyethylene with a melt index of 3.7 g / 10 min and a weight-average molecular weight of 180,000, 7 parts by weight of ethylene-octene random copolymer with a melt index of 3.6 g / 10 min and a weight-average molecular weight of 170,000 (the mass content of octene is 23%), and then take 0.15 parts by weight of di(trimethylbenzylidene)sorbitol, 0.15 parts by weight of 2,2'-methylene-bis( 4,6-di-tert-butylphenoxy) sodium phosphate, 1 part by weight of high-density polyethylene grafted maleic anhydride (grafting rate 1.3%), 1 part by weight of linear low-density polyethylene grafted maleic anhydride (grafting rate 1.3%), 0.5 parts by weight of antioxidant 1076, 0.04 parts by weight of 4,4-bis(5-methyl-2-benzoxazolyl)stilbene, 0.04 parts by weight of 1,4-bis(5-methyl-2-benzoxazolyl)naphthalene, 0.14 parts by weight of calcium sulfate, 0.14 parts by weight of barium sulfate, 0.05 parts by weight of oleic acid amide, 0.05 parts by weight of stearic acid amide, placed in a mixer, mixed at room temperature for 25 minutes, and the speed was set to 300 rpm. After that, the mixed materials were granulated in a twin-screw extruder, the blending temperature was set to 185°C, the die temperature was set to 175°C, and the screw extrusion speed was 150 rpm. After granulation, the product is dried in an oven at 55°C to obtain a special material for the middle layer polyethylene cast film.

[0110] The obtained middle layer polyethylene cast film special material is put into the bubble film machine, the processing temperature is 200°C, the rotation speed is set to 350 rpm, the extruded polyethylene is cast and vacuum adsorbed by the bubble roller to form a bubble film; the vacuum degree of the bubble roller is 0.04MPa, the bubble diameter is 10mm, and the bubble height is 5mm.

[0111] Preparation of bubble bags:

[0112] After the bubble film is stably formed, the prepared outer layer of high-strength polyethylene woven cloth and the inner layer of polyethylene heat-sealing film are introduced into the machine through the traction roller to be compounded with the bubble film. The outer layer of high-strength polyethylene woven cloth is compounded with the bubble film at the bubble roller, that is, while forming the bubble film, it is pressed together with the outer layer of high-strength polyethylene woven cloth, the compounding temperature is 100°C, and the compounding pressure is 0.3MPa. Next, the side of the bubble film that forms the bubble is pressed together with the linear low-density polyethylene layer of the inner layer of polyethylene heat-sealing film, and the compounding temperature is 93°C. After trimming and winding, a high-strength composite polyethylene bubble film is obtained. Finally, the rolled polyethylene bubble film is introduced into the bag making machine, and after cutting, bending, hot pressing and sealing steps, a high-strength composite polyethylene bubble bag is obtained, and the hot pressing temperature is 98°C. After testing, the tensile strength of the polyethylene bubble film described in this embodiment is 46.4MPa, the elongation at break is 225.1%, and the heat sealing strength is 21.7N / 15mm; the crystallinity of each layer is shown in Table 1.

[0113] Example 4

[0114] Outer layer high strength polyethylene woven fabric preparation:

[0115] First, 100 parts by weight of high-density polyethylene with a melt index of 4.5 g / 10 min and a weight-average molecular weight of 270,000, 8 parts by weight of linear low-density polyethylene with a melt index of 3.5 g / 10 min and a weight-average molecular weight of 190,000, 17 parts by weight of ethylene-octene block copolymer with a melt index of 3.5 g / 10 min and a weight-average molecular weight of 220,000 (the mass content of octene is 24%), and then 1.2 parts by weight of high-density polyethylene grafted with maleic anhydride (grafting rate is 1.4%), 1.3 parts by weight of linear low-density polyethylene grafted with maleic anhydride (grafting rate is 1 .4%), 0.4 weight parts of antioxidant 168, 0.4 weight parts of antioxidant 1010, 0.04 weight parts of 1,4-di(benzoxazolyl-2-yl)naphthalene, 0.04 weight parts of 4,4-bis(5-methyl-2-benzoxazolyl)stilbene, 1.7 weight parts of fatty amine ethoxy ether (fatty chain length is 12), 1.8 weight parts of phosphate fatty alcohol ester (fatty chain length is 16), 0.7 weight parts of chlorinated paraffin, 0.8 weight parts of chlorinated paraffin, 0.8 weight parts of magnesium hydroxide, placed in a mixer, mixed at room temperature for 27 minutes. After that, the mixed materials are granulated in a twin-screw extruder, the blending temperature is set to 192°C, the die temperature is set to 177°C, and the screw extrusion speed is 175 rpm. After granulation, it is dried in an oven at 75°C to obtain a special material for the outer layer of high-strength polyethylene woven cloth.

[0116] The special material for the outer layer of polyethylene woven cloth is put into the casting equipment, the processing temperature is set to 215℃, the extruder die temperature is 205℃, the casting roller temperature is 105℃, the draft ratio is 35, the distance between the extruder die and the casting roller is 275mm, and it is cut and rolled after cooling to obtain a preliminary cast film with a lamellar structure. Then the preliminary cast film is annealed at 108℃ for 1.7h, recrystallized to improve the crystallinity, and form a highly crystalline core-shell structure. After cooling again, it is cut into flat wires with a width of 3.5mm. It is hot stretched at 115℃ with a stretching multiple of 2.7 times, and shaped at 115℃ to obtain the required warp and weft wires with high strength and high orientation. Finally, it is woven by a circular loom, and the final woven cloth is obtained by slitting and rolling. The density of the woven cloth is 171g / m 2 After testing, the tensile load of the woven fabric is 852N / 50mm.

[0117] Preparation of inner polyethylene heat-sealing film:

[0118] First, take 100 parts by weight of highly branched linear low-density polyethylene (melt index of 2.7g / 10min, weight average molecular weight of 240,000, and degree of branching of 16‰), 9 parts by weight of metallocene linear low-density polyethylene (melt index of 1.8g / 10min, weight average molecular weight of 180,000), 9 parts by weight of metallocene ultra-low density polyethylene (melt index of 1.8g / 10min, weight average molecular weight of 180,000) and 28 parts by weight of ethylene-octene random copolymer (melt index of 4.0g / 10min, weight average molecular weight of 190,000, wherein the mass content of octene is 24%), place in a mixer, mix at room temperature for 27min, and set the speed to 350 rev / min. Then, granulate the mixed materials in a twin-screw extruder, set the blending temperature to 177°C, the die head temperature to 167°C, and the screw extrusion speed to 175 rev / min. After granulation, use an oven to dry at 57°C to obtain a special material for inner polyethylene heat-sealing film.

[0119] The above-mentioned highly branched linear low-density polyethylene and the inner layer polyethylene heat-sealing film special material are respectively put into different hoppers of the co-extrusion casting equipment, the processing temperature is set to 205°C, the casting die temperature is 196°C, the casting roller temperature is 87°C, the cooling roller temperature is 32°C, the melt draw ratio is 5.2, and then cutting and winding are carried out to obtain the inner layer polyethylene cast heat-sealing film.

[0120] Preparation of middle bubble film:

[0121] First, 100 parts by weight of a high-density polyethylene having a melt index of 4.5 g / 10 min and a weight-average molecular weight of 270,000, 9 parts by weight of a highly branched linear low-density polyethylene having a melt index of 2.7 g / 10 min and a weight-average molecular weight of 240,000 (branching degree of 16‰), 9 parts by weight of a highly branched linear low-density polyethylene having a melt index of 2.8 g / 10 min and a weight-average molecular weight of 200,000 (branching degree of 14‰), 9 parts by weight of a metallocene linear low-density polyethylene having a melt index of 4.2 g / 10 min and a weight-average molecular weight of 190,000, 9 parts by weight of a metallocene linear low-density polyethylene having a melt index of 4.5 g / 10 min and a weight-average molecular weight of 200,000, 9 parts by weight of an ethylene-octene random copolymer (octene having a melt index of 4.2 g / 10 min and a weight-average molecular weight of 180,000) were taken. The mass content is 24%), and then 0.2 weight parts of sodium dehydroabietate, 0.2 weight parts of calcium rosinate, 1.2 weight parts of linear low-density polyethylene grafted with glycidyl methacrylate (grafting rate is 1.3%), 1.3 weight parts of high-density polyethylene grafted with maleic anhydride (grafting rate is 1.4%), 0.4 weight parts of antioxidant 1076, 0.4 weight parts of antioxidant 1010, 0.04 weight parts of 4,4-bis(5-methyl-2-benzoxazolyl)stilbene, 0.04 weight parts of 2,5-di(5-tert-butyl-2-benzoxazolyl)thiophene, 0.42 weight parts of silica, 0.1 weight parts of behenic acid amide, and 0.1 weight parts of oleic acid amide are placed in a blender and mixed at room temperature for 27 minutes with the speed set to 350 rpm. The mixed material was then pelletized in a twin-screw extruder, with the blending temperature set at 187°C, the die temperature set at 177°C, and the screw extrusion speed set at 175 rpm. After pelletization, the material was dried in an oven at 57°C to obtain a special material for the middle layer polyethylene cast film.

[0122] The obtained middle layer polyethylene cast film special material is put into the bubble film machine, the processing temperature is 205°C, the rotation speed is set to 450 rpm, and the extruded polyethylene raw material is compounded into a bubble film by casting and vacuum adsorption of the bubble roller; the vacuum degree of the bubble roller is 0.04MPa, the bubble diameter is 11mm, and the bubble height is 6mm.

[0123] Preparation of bubble bags:

[0124] After the bubble film is stably formed, the prepared outer layer of high-strength polyethylene woven cloth and the inner layer of polyethylene heat-sealing film are introduced into the machine through the traction roller to be compounded with the bubble film. The outer layer of high-strength polyethylene woven cloth is compounded with the bubble film at the bubble roller, that is, while forming the bubble film, it is pressed together with the outer layer of high-strength polyethylene woven cloth, the compounding temperature is 105°C, and the compounding pressure is 0.35MPa. Next, the side of the bubble film that forms the bubble is pressed together with the linear low-density polyethylene layer of the inner layer of polyethylene heat-sealing film, and the compounding temperature is 94°C. After trimming and winding, a high-strength composite polyethylene bubble film is obtained. Finally, the rolled composite polyethylene bubble film is introduced into the bag making machine, and after cutting, bending, hot pressing and sealing steps, a high-strength composite polyethylene bubble bag is obtained, and the hot pressing temperature is 99°C. After testing, the tensile strength of the polyethylene bubble film described in this embodiment is 53.6MPa, the elongation at break is 187.5%, and the heat sealing strength is 23.8N / 15mm; the crystallinity of each layer is shown in Table 1.

[0125] Example 5

[0126] Outer layer high strength polyethylene woven fabric preparation:

[0127] First, 100 parts by weight of high-density polyethylene with a melt index of 5.0 g / 10 min and a weight-average molecular weight of 300,000, 5 parts by weight of linear low-density polyethylene with a melt index of 4.0 g / 10 min and a weight-average molecular weight of 200,000, 5 parts by weight of linear low-density polyethylene with a melt index of 3.5 g / 10 min and a weight-average molecular weight of 170,000, 10 parts by weight of ethylene-octene block copolymer with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 250,000 (the mass content of octene is 25%), 10 parts by weight of ethylene-octene block copolymer with a melt index of 4.0 g / 10 min and a weight-average molecular weight of 250,000 (the mass content of octene is 20%), and then 1 part by weight of high-density polyethylene grafted with glycidyl methacrylate (grafting rate is 1.2%), 1 part by weight of linear low-density polyethylene grafted with maleic anhydride (grafting rate of 1.5%), 1 part by weight of ethylene-octene block copolymer grafted with maleic anhydride (grafting rate of 1.5%), 0.3 part by weight of antioxidant 168, 0.3 part by weight of antioxidant 1010, 0.4 part by weight of antioxidant 1098, 0.05 part by weight of 2,5-di(5-tert-butyl-2-benzoxazolyl)thiophene, 0.05 part by weight of 1,4-di(benzoxazolyl-2-yl)naphthalene, 2 parts by weight of fatty amine ethoxy ether (fatty chain length of 18), 2 parts by weight of polyol fatty acid ester (total fatty chain length of 18), 0.7 part by weight of chlorinated paraffin, 0.7 part by weight of antimony trioxide, and 0.6 part by weight of aluminum hydroxide are placed in a blender and mixed at room temperature for 30 minutes. The mixed material was then pelletized in a twin-screw extruder, with the blending temperature set at 195°C, the die temperature set at 180°C, and the screw extrusion speed set at 200 rpm. After pelletization, the material was dried in an oven at 80°C to obtain a special material for the outer layer of high-strength polyethylene woven fabric.

[0128] The special material for the outer layer of polyethylene woven cloth is put into the casting equipment, the processing temperature is set to 220℃, the extruder die temperature is 210℃, the casting roller temperature is 110℃, the draft ratio is 40, the distance between the extruder die and the casting roller is 300mm, and it is cut and rolled after cooling to obtain a preliminary cast film with a lamellar structure. Then the preliminary cast film is annealed at 110℃ for 2h, recrystallized to improve the crystallinity, and form a highly crystalline core-shell structure. After cooling again, it is cut into flat wires with a width of 4mm. It is hot stretched at 120℃ with a stretching multiple of 3 times, and shaped at 120℃ to obtain the required warp and weft wires with high strength and high orientation. Finally, it is woven by a circular loom, and the final woven cloth is obtained by slitting and rolling. The density of the woven cloth is 180g / m 2 After testing, the tensile load of the woven fabric is 937N / 50mm.

[0129] Preparation of inner polyethylene heat-sealing film:

[0130] First, take 50 parts by weight of highly branched linear low-density polyethylene (melt index of 3.0 g / 10 min, weight average molecular weight of 250,000, and degree of branching of 17‰), 50 parts by weight of highly branched linear low-density polyethylene (melt index of 2.5 g / 10 min, weight average molecular weight of 200,000, and degree of branching of 17‰), 10 parts by weight of metallocene linear low-density polyethylene (melt index of 2.0 g / 10 min, weight average molecular weight of 200,000), 10 parts by weight of metallocene ultra-low-density polyethylene (melt index of 1.0 g / 10 min, weight average molecular weight of 200,000), and 10 parts by weight of metallocene ultra-low-density polyethylene (melt index of 1.0 g / 10 min, weight average molecular weight of 200,000). 15 parts by weight of ethylene-octene random copolymer (melt index is 2.0g / 10min, weight average molecular weight is 200,000, of which the mass content of octene is 25%), 15 parts by weight of ethylene-octene random copolymer (melt index is 4.0g / 10min, weight average molecular weight is 180,000, of which the mass content of octene is 22%), placed in a mixer, mixed at room temperature for 30min, the speed is set to 400 rpm. After that, the mixed materials are granulated in a twin-screw extruder, the blending temperature is set to 180℃, the die temperature is set to 170℃, and the screw extrusion speed is 200 rpm. After granulation, it is dried in an oven at 60℃ to obtain a special material for inner polyethylene heat-sealing film.

[0131] The above-mentioned highly branched linear low-density polyethylene and the inner layer polyethylene heat-sealing film special material are respectively put into different hoppers of the co-extrusion casting equipment, the processing temperature is set to 210°C, the casting die temperature is 200°C, the casting roller temperature is 90°C, the cooling roller temperature is 35°C, the melt stretching ratio is 6, and then cutting and winding are carried out to obtain the inner layer polyethylene cast heat-sealing film.

[0132] Preparation of middle bubble film:

[0133] First, take 50 parts by weight of a high-density polyethylene with a melt index of 5.0 g / 10 min and a weight-average molecular weight of 300,000, 50 parts by weight of a high-density polyethylene with a melt index of 4.0 g / 10 min and a weight-average molecular weight of 250,000, 10 parts by weight of a highly branched linear low-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 250,000 (branching degree of 17‰), 10 parts by weight of a highly branched linear low-density polyethylene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 200,000 ( The branching degree is 16‰), 10 parts by weight of a metallocene linear low-density polyethylene with a melt index of 5.0 g / 10min and a weight average molecular weight of 200,000, 10 parts by weight of a metallocene linear low-density polyethylene with a melt index of 4.0 g / 10min and a weight average molecular weight of 180,000, 5 parts by weight of an ethylene-octene random copolymer with a melt index of 5.0 g / 10min and a weight average molecular weight of 200,000 (the mass content of octene is 25%), 5 parts by weight of a melt index of 4.0 g / 10min and a weight average molecular weight of 1 80,000 ethylene-octene random copolymer (octene content is 24%), 0.2 weight parts of di(p-methylbenzylidene) allyl sorbitol, 0.2 weight parts of sodium bis(2-tert-butyl, 4-methylphenoxy) phosphate, 0.1 weight parts of rosin acid amide, 1 weight part of high-density polyethylene grafted glycidyl methacrylate (grafting rate is 1.5%), 1 weight part of high-density polyethylene grafted maleic anhydride (grafting rate is 1.4%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.2%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.6%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.7%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.9%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.8%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.9%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.7%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.8%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.9%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.8%), 1 weight part of linear low-density polyethylene grafted maleic anhydride (grafting rate is 1.8%), 1 weight part of linear low-density polyethylene grafted The branch rate is 1.4%), 0.5 weight parts of antioxidant 1076, 0.5 weight parts of antioxidant 1098, 0.05 weight parts of 1,4-di(benzoxazolyl-2-yl)naphthalene, 0.05 weight parts of 1,4-di(5-methyl-2-benzoxazolyl)naphthalene, 0.2 weight parts of calcium hydrogen phosphate, 0.2 weight parts of barium sulfate, 0.1 weight parts of oleic acid amide, 0.1 weight parts of stearic acid amide, placed in a blender, mixed at room temperature for 30 minutes, and the speed was set to 400 rpm. After that, the mixed materials were granulated in a twin-screw extruder, the blending temperature was set to 190°C, the die temperature was set to 180°C, and the screw extrusion speed was 200 rpm. After granulation, it was dried in an oven at 60°C to obtain a special material for the middle layer polyethylene cast film.

[0134] The obtained middle layer polyethylene cast film special material is put into the bubble film machine, the processing temperature is 210°C, the rotation speed is set to 500 rpm, and the extruded polyethylene raw material is cast and vacuum adsorbed by the bubble roller to form a bubble film; the vacuum degree of the bubble roller is 0.04MPa, the bubble diameter is 12mm, and the bubble height is 7mm.

[0135] Preparation of bubble bags:

[0136] After the bubble film is stably formed, the prepared outer layer of high-strength polyethylene woven cloth and the inner layer of polyethylene heat-sealing film are introduced into the machine through the traction roller to be compounded with the bubble film. The outer layer of high-strength polyethylene woven cloth is compounded with the bubble film at the bubble roller, that is, while forming the bubble film, it is pressed together with the outer layer of high-strength polyethylene woven cloth, the compounding temperature is 110°C, and the compounding pressure is 0.4MPa. Next, the side of the bubble film that forms the bubble is pressed together with the linear low-density polyethylene layer of the inner layer of polyethylene heat-sealing film, and the compounding temperature is 95°C. After trimming and winding, a high-strength composite polyethylene bubble film is obtained. Finally, the rolled composite polyethylene bubble film is introduced into the bag making machine, and after cutting, bending, hot pressing and sealing steps, a high-strength composite polyethylene bubble bag is obtained, and the hot pressing temperature is 100°C. After testing, the tensile strength of the polyethylene bubble film described in this embodiment is 59.2MPa, the elongation at break is 172.3%, and the heat sealing strength is 24.9N / 15mm; the crystallinity of each layer is shown in Table 1.

[0137] Comparative Example 1

[0138] Preparation of inner polyethylene heat-sealing film: First, take 100 parts by weight of highly branched linear low-density polyethylene (melt index of 2.0 g / 10 min, weight average molecular weight of 200,000, and degree of branching of 14‰), 10 parts by weight of metallocene linear low-density polyethylene (melt index of 1.0 g / 10 min, weight average molecular weight of 150,000), and 20 parts by weight of ethylene-octene random copolymer (melt index of 2.0 g / 10 min, weight average molecular weight of 150,000, wherein the mass content of octene is 20%), place in a mixer, mix at room temperature for 20 min, and set the speed to 200 rpm. Then, granulate the mixed materials in a twin-screw extruder, set the blending temperature to 170°C, the die temperature to 160°C, and the screw extrusion speed to 100 rpm. After granulation, use an oven to dry at 50°C to obtain a special material for inner polyethylene heat-sealing film.

[0139] The above-mentioned highly branched linear low-density polyethylene and the inner layer polyethylene heat-sealing film special material are respectively put into different hoppers of the co-extrusion casting equipment, the processing temperature is set to 190°C, the casting die temperature is 185°C, the casting roller temperature is 80°C, the cooling roller temperature is 25°C, the melt stretching ratio is 3, and then cutting and winding are carried out to obtain the inner layer polyethylene cast heat-sealing film.

[0140] Preparation of outer bubble film: First, take 100 parts by weight of high-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 200,000, 10 parts by weight of highly branched linear low-density polyethylene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 200,000, 10 parts by weight of metallocene linear low-density polyethylene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000, 5 parts by weight of ethylene- Octene random copolymer (octene content is 20%), then take 0.1 weight part of dibenzylidene sorbitol, 1 weight part of high-density polyethylene grafted methacrylate glycidyl ester (grafting rate is 1%), 0.1 weight part of antioxidant 168, 0.04 weight part of 4,4-bis (5-methyl-2-benzoxazolyl) diphenylethylene, 0.1 weight part of calcium sulfate, 0.01 weight part of behenic acid amide, place in a mixer, mix at room temperature for 20 minutes, and set the speed to 200 rpm. Then, the mixed material is granulated in a twin-screw extruder, the blending temperature is set to 180°C, the die temperature is set to 170°C, and the screw extrusion speed is 100 rpm. After granulation, it is dried in an oven at 50°C to obtain a special material for the outer polyethylene cast film.

[0141] The obtained outer layer polyethylene cast film special material is put into the bubble film machine, the processing temperature is 190°C, the rotation speed is set to 300 rpm, and the extruded polyethylene raw material is cast and vacuum adsorbed by the bubble roller to form a bubble film; the vacuum degree of the bubble roller is 0.04MPa, the bubble diameter is 8mm, and the bubble height is 3mm.

[0142] Preparation of bubble bags: After the bubble film is stably formed, the prepared inner polyethylene heat-sealing film is introduced into the machine through a traction roller to be compounded with the bubble film. The side of the bubble film that forms the bubble is pressed together with the inner polyethylene heat-sealing film, and the compounding temperature is 90°C. After trimming and rolling, the composite polyethylene bubble film is obtained. Finally, the rolled polyethylene bubble film is introduced into the bag making machine, and after cutting, bending, hot pressing and sealing, a composite polyethylene bubble bag is obtained, and the hot pressing temperature is 95°C. After testing, the tensile strength of the polyethylene bubble film is 31.9MPa, the elongation at break is 390.3%, and the heat sealing strength is 17.8N / 15mm, and its heat sealing strength has decreased.

[0143] Comparative Example 2

[0144] Preparation of outer layer high-strength polyethylene woven cloth: First, take 100 parts by weight of high-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 200,000, 2 parts by weight of linear low-density polyethylene with a melt index of 2.0-4.0 g / 10 min and a weight-average molecular weight of 150,000, 10 parts by weight of ethylene-octene block copolymer with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000 (the mass content of octene is 20%), then take 1 part by weight of high-density polyethylene grafted with glycidyl methacrylate (grafting rate is 1%), 0.1 part by weight of antioxidant 168, 0.04 part by weight of 1,4-di(benzoxazolyl-2-yl)naphthalene, 2 parts by weight of fatty amine ethoxy ether (fat chain length is 10), and 0.1 part by weight of chlorinated paraffin, place them in a blender, and mix them at room temperature for 20 minutes. The mixed material was then pelletized in a twin-screw extruder, with the blending temperature set at 185°C, the die temperature set at 170°C, and the screw extrusion speed set at 100 rpm. After pelletization, the material was dried in an oven at 60°C to obtain a special material for the outer layer of high-strength polyethylene woven fabric.

[0145] Put the special material for the outer layer of polyethylene woven cloth into the casting equipment, set the processing temperature to 200℃, the extruder die temperature to 190℃, the casting roller temperature to 90℃, the draft ratio to 20, the distance between the extruder die and the casting roller to 200mm, and cut and roll it after cooling to obtain a preliminary cast film with a lamellar structure. Then anneal the preliminary cast film at 100℃ for 1h, recrystallize it to improve the crystallinity, and form a highly crystalline core-shell structure. After cooling again, cut it into flat wires with a width of 2mm, heat stretch it at 90℃, the stretching multiple is 2 times, and it is shaped at 100℃ to obtain the required warp and weft wires with high strength and high orientation. Finally, it is woven by a circular loom, and the final woven cloth is obtained by slitting and rolling. The density of the woven cloth is 150g / m 2 After testing, the tensile load of the woven fabric is 625N / 50mm.

[0146] Preparation of inner bubble film: First, take 100 parts by weight of high-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 200,000, 10 parts by weight of highly branched linear low-density polyethylene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 200,000, 10 parts by weight of metallocene linear low-density polyethylene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000, 5 parts by weight of ethylene-octene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000 Random copolymer (octene content is 20%), then take 0.1 weight part of dibenzylidene sorbitol, 1 weight part of high-density polyethylene grafted methacrylate glycidyl ester (grafting rate is 1%), 0.1 weight part of antioxidant 168, 0.04 weight part of 4,4-bis (5-methyl-2-benzoxazolyl) diphenylethylene, 0.1 weight part of calcium sulfate, 0.01 weight part of behenic acid amide, place in a mixer, mix at room temperature for 20 minutes, and set the speed to 200 rpm. Then, the mixed material is granulated in a twin-screw extruder, the blending temperature is set to 180°C, the die temperature is set to 170°C, and the screw extrusion speed is 100 rpm. After granulation, use an oven to dry at 50°C to obtain a special material for the inner layer polyethylene cast film.

[0147] The obtained inner layer polyethylene cast film special material is put into the bubble film machine, the processing temperature is 190°C, the rotation speed is set to 300 rpm, and the extruded polyethylene is cast, vacuum adsorbed by the bubble roller, and compounded into a bubble film; the vacuum degree of the bubble roller is 0.04MPa, the bubble diameter is 8mm, and the bubble height is 3mm.

[0148] Preparation of bubble bags: After the bubble film is stably formed, the prepared outer layer of high-strength polyethylene woven cloth is introduced into the machine through the traction roller to be compounded with the bubble film. The outer layer of high-strength polyethylene woven cloth is compounded with the bubble film at the bubble roller, that is, while forming the bubble film, it is pressed together with the outer layer of high-strength polyethylene woven cloth. The compounding temperature is 90°C and the compounding pressure is 0.2MPa. After trimming and winding, a composite polyethylene bubble film is obtained. Finally, the rolled polyethylene bubble film is introduced into the bag making machine, and after cutting, bending, hot pressing and sealing steps, a composite polyethylene bubble bag is obtained, and the hot pressing temperature is 95°C. After testing, the tensile strength of the polyethylene bubble film is 40.2MPa, the elongation at break is 315.6%, the heat sealing strength is 5.6N / 15mm, and its toughness decreases significantly.

[0149] Comparative Example 3

[0150] Preparation of outer polyethylene film: First, take 100 parts by weight of high-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 200,000, 2 parts by weight of linear low-density polyethylene with a melt index of 2.0-4.0 g / 10 min and a weight-average molecular weight of 150,000, 10 parts by weight of ethylene-octene block copolymer with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000 (the mass content of octene is 20%), then take 1 part by weight of high-density polyethylene grafted with glycidyl methacrylate (grafting rate is 1%), 0.1 part by weight of antioxidant 168, 0.04 part by weight of 1,4-di(benzoxazolyl-2-yl)naphthalene, 2 parts by weight of fatty amine ethoxy ether (fat chain length is 10), and 0.1 part by weight of chlorinated paraffin, place them in a blender, and mix at room temperature for 20 minutes. The mixed material was then granulated in a twin-screw extruder, with the blending temperature set at 185°C, the die temperature set at 170°C, and the screw extrusion speed set at 100 rpm. After granulation, the material was dried in an oven at 60°C to obtain a special material for the outer layer.

[0151] The outer layer special material is put into the film blowing machine, the processing temperature is set to 200°C, the blowing ratio is 3.0, the air ring is cooled after molding, and the rotation traction is performed after cooling, the traction ratio is 4, and then it is cut and rolled to obtain the outer layer polyethylene film.

[0152] Preparation of inner polyethylene heat-sealing film: Take 100 parts by weight of highly branched linear low-density polyethylene (melt index of 2.0 g / 10 min, weight average molecular weight of 200,000, and degree of branching of 14‰), put it into the hopper of the co-extrusion casting equipment, set the processing temperature to 190°C, the casting die temperature to 185°C, the casting roller temperature to 80°C, the cooling roller temperature to 25°C, the melt stretching ratio to 3, and then cut and roll it to obtain the inner polyethylene cast heat-sealing film.

[0153] Preparation of middle bubble film: First, take 100 parts by weight of high-density polyethylene with a melt index of 3.0 g / 10 min and a weight-average molecular weight of 200,000, 10 parts by weight of highly branched linear low-density polyethylene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 200,000, 10 parts by weight of metallocene linear low-density polyethylene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000, 5 parts by weight of ethylene-octene with a melt index of 2.0 g / 10 min and a weight-average molecular weight of 150,000 Random copolymer (octene content is 20%), then take 0.1 weight part of dibenzylidene sorbitol, 1 weight part of high-density polyethylene grafted methacrylate glycidyl ester (grafting rate is 1%), 0.1 weight part of antioxidant 168, 0.04 weight part of 4,4-bis (5-methyl-2-benzoxazolyl) diphenylethylene, 0.1 weight part of calcium sulfate, 0.01 weight part of behenic acid amide, place in a mixer, mix at room temperature for 20 minutes, and set the speed to 200 rpm. Then, the mixed material is granulated in a twin-screw extruder, the blending temperature is set to 180°C, the die temperature is set to 170°C, and the screw extrusion speed is 100 rpm. After granulation, it is dried in an oven at 50°C to obtain a special material for middle-layer polyethylene cast film.

[0154] The obtained middle layer polyethylene cast film special material is put into the bubble film machine, the processing temperature is 190°C, the rotation speed is set to 300 rpm, and the extruded polyethylene is cast and vacuum adsorbed by the bubble roller to form a bubble film; the vacuum degree of the bubble roller is 0.04MPa, the bubble diameter is 8mm, and the bubble height is 3mm.

[0155] Preparation of bubble bags:

[0156] After the bubble film is stably formed, the prepared outer polyethylene film and inner polyethylene heat-sealing film are introduced into the machine through the traction roller to be compounded with the bubble film. The outer polyethylene film is compounded with the bubble film at the bubble roller, that is, while forming the bubble film, it is pressed together with the outer polyethylene film, the compounding temperature is 90°C, and the compounding pressure is 0.2MPa. Next, the side of the bubble film that forms the bubble is pressed together with the inner polyethylene heat-sealing film, and the compounding temperature is 90°C. After trimming and winding, a composite polyethylene bubble film is obtained. Finally, the rolled polyethylene bubble film is introduced into the bag making machine, and after cutting, bending, hot pressing and sealing steps, a composite polyethylene bubble bag is obtained, and the hot pressing temperature is 95°C. After testing, the tensile strength of the polyethylene bubble film is 33.5MPa, the elongation at break is 387.1%, and the heat sealing strength is 5.4N / 15mm.

[0157] Comparative Example 4

[0158] The preparation method of the outer polyethylene woven cloth, the inner polyethylene heat-sealing film, the middle bubble film and the bubble bag of this comparative example is the same as that of Example 1, except that the linear low-density polyethylene, the ethylene-octene block copolymer and the high-density polyethylene grafted glycidyl methacrylate are removed when preparing the outer polyethylene woven cloth. After testing, the tensile load of the outer woven cloth is 673N / 50mm, the tensile strength of the polyethylene bubble film is 41.3MPa, the elongation at break is 273.6% (the elongation at break is significantly reduced), and the heat sealing strength is 18.1N / 15mm.

[0159] Comparative Example 5

[0160] The preparation method of the outer polyethylene woven cloth, the inner polyethylene heat-sealing film, the middle bubble film and the bubble bag of this comparative example is the same as that of Example 1, except that: when preparing the inner polyethylene heat-sealing film, the highly branched linear low-density polyethylene is replaced with a linear low-density polyethylene with a branching degree of 6.0‰. After testing, the tensile load of the outer woven cloth is 625N / 50mm, the tensile strength of the polyethylene bubble film is 38.9MPa, the elongation at break is 329.5%, and the heat sealing strength is 17.0N / 15mm.

[0161] Comparative Example 6

[0162] The preparation method of the outer polyethylene woven cloth, the inner polyethylene heat-sealing film, the middle bubble film and the bubble bag of this comparative example is the same as that of Example 1, except that the organic nucleating agent is removed when preparing the middle bubble film layer. After testing, the tensile load of the outer woven cloth is 625N / 50mm, the tensile strength of the polyethylene bubble film is 38.2MPa, the elongation at break is 301.4%, and the heat sealing strength is 18.0N / 15mm. The crystallinity of each layer in each comparative example is also shown in Table 1.

[0163] Table 1 Crystallinity of each layer of polyethylene bubble film

[0164] serial number Outer woven fabric / % Middle layer bubble film / % Inner heat sealing film / % Example 1 72.1 36.6 27.2 Example 2 71.5 38.5 26.5 Example 3 70.3 38.7 26.1 Example 4 69.5 39.0 25.8 Example 5 70.4 39.4 25.4 Comparative Example 1 / 36.6 27.2 Comparative Example 2 72.1 36.6 / Comparative Example 3 41.4 36.6 28.4 Comparative Example 4 73.2 36.6 27.2 Comparative Example 5 72.1 36.6 27.6 Comparative Example 6 72.1 42.9 27.2

[0165] By comparison, it can be seen that the composite polyethylene bubble film of the present invention has high strength, can be recycled, and is environmentally friendly. The above examples are only used to illustrate the technical features and implementation process of the present invention, but not to limit the technical solution of the present invention. It should be pointed out that for ordinary technicians in this field, the present invention can still be modified or replaced by equivalents, and the modification or replacement that does not deviate from the principle of the present invention is covered by the protection of the present invention.

Claims

1. A high-strength composite polyethylene bubble film, characterized in that: It includes a high-strength polyethylene woven cloth layer, a polyethylene cast bubble film layer and a polyethylene heat-sealed film layer which are compounded in sequence; The raw materials of the high-strength polyethylene woven fabric layer include a first high-density polyethylene, a first linear low-density polyethylene, an ethylene-octene block copolymer, a first compatibilizer and a first functional additive; the high-strength polyethylene woven fabric layer uses the first high-density polyethylene as the woven fabric layer matrix; The raw materials of the polyethylene cast bubble film layer include a second high-density polyethylene, a second linear low-density polyethylene, a metallocene linear low-density polyethylene, a first ethylene-octene random copolymer, an organic nucleating agent, a second compatibilizer and a second functional additive; the polyethylene cast bubble film uses the second high-density polyethylene as the bubble film layer matrix; The raw materials of the polyethylene heat-sealing film layer include branched linear low-density polyethylene, metallocene polyethylene and a second ethylene-octene random copolymer; the polyethylene heat-sealing film layer has a double-layer structure, and the branched linear low-density polyethylene is the main body of the heat-sealing film layer.

2. The composite polyethylene bubble film according to claim 1, characterized in that In the raw materials of the high-density polyethylene woven fabric layer, the mass ratio of the first high-density polyethylene, the first linear low-density polyethylene and the ethylene-octene block copolymer is 100:5-10:10-20; In the raw materials of the polyethylene cast bubble film layer, the mass ratio of the second high-density polyethylene, the second linear low-density polyethylene, the metallocene linear low-density polyethylene and the first ethylene-octene random copolymer is: 100:10-20:15-20:5-10; In the raw materials of the polyethylene heat-sealing film layer, the mass ratio of the branched linear low-density polyethylene, the metallocene polyethylene and the second ethylene-octene random copolymer is 100:10-20:20-30.

3. The composite polyethylene bubble film according to claim 1, characterized in that The weight average molecular weight of the ethylene-octene block copolymer is 150,000-250,000; the second linear low-density polyethylene is a branched linear low-density polyethylene with a branching degree of 14-17‰; the weight average molecular weights of the first ethylene-octene random copolymer and the second ethylene-octene random copolymer are respectively 150,000-200,000.

4. The composite polyethylene bubble film according to claim 1, characterized in that The first compatibilizer and the second compatibilizer are glycidyl methacrylate graft copolymer and / or maleic anhydride graft copolymer respectively; the organic nucleating agent is one or more of a sorbitol nucleating agent, a phosphate nucleating agent and a rosin-based nucleating agent.

5. The composite polyethylene bubble film according to any one of claims 1 to 4, characterized in that: The first functional auxiliary agent is one or more of an antioxidant, a brightener, an antistatic agent and a flame retardant; the second functional auxiliary agent is one or more of an antioxidant, a brightener, an anti-blocking agent and a lubricant.

6. The method for preparing the composite polyethylene bubble film according to any one of claims 1 to 5, characterized in that: The following steps are involved: A first high-density polyethylene, a first linear low-density polyethylene, an ethylene-octene block copolymer, a first compatibilizer and a first functional additive are mixed and granulated to obtain a special material for an outer layer woven fabric; the special material for the outer layer woven fabric is formed into a preliminary cast film with a lamellar structure by a melt stretching method, and then a crystalline cast film with a core-shell structure is obtained by heat treatment, which is cut into flat yarns, and then a high-strength high-oriented flat yarn is obtained by a heat stretching method, and the flat yarns are used as warp yarns and weft yarns to prepare a woven fabric; The second high-density polyethylene, the second linear low-density polyethylene, the metallocene linear low-density polyethylene, the first ethylene-octene random copolymer, the organic nucleating agent, the second compatibilizer and the second functional additive are mixed and granulated to obtain a special material for the middle layer cast film; the special material for the middle layer cast film is melt-extruded, and the film is cast and vacuum-adsorbed by a bubble roller to obtain a bubble film substrate; The branched linear low-density polyethylene, the metallocene polyethylene and the second ethylene-octene random copolymer are mixed and granulated to obtain a special material for the inner layer heat-sealing film; the special material for the inner layer heat-sealing film and another branched linear low-density polyethylene are subjected to double-layer co-extrusion casting to obtain a heat-sealing film; The woven cloth and the heat-sealing film are respectively used to cover the two surfaces of the bubble film substrate, the woven cloth is pressed against one side of the bubble film substrate to form a plurality of bubble structures, and the other side of the bubble film substrate is pressed against the branched linear low-density polyethylene of the heat-sealing film to obtain a high-strength composite polyethylene bubble film.

7. The preparation method according to claim 6, characterized in that: In the melt stretching method of the outer layer woven cloth special material, the draft ratio is 20-40; the temperature of the preliminary cast film heat treatment is 100-110°C; in the flat wire hot stretching method, the flat wire width is 2-4mm, the temperature is 90-120°C, the stretching multiple is 2-3 times, and it is shaped at a temperature of 100-120°C.

8. The preparation method according to claim 6, characterized in that: In the double-layer co-extrusion casting, the processing temperature is 190-210°C and the melt draw ratio is 3-6; the blending temperature of the granulation to obtain the special material for the middle layer cast film is 180-190°C, the processing temperature of the melt extrusion is 190-210°C, and the bubble diameter of the bubble film substrate is 8-12mm.

9. A high-strength composite polyethylene bubble bag, characterized in that: The composite polyethylene bubble film according to any one of claims 1 to 5 is formed by a bag making process.

10. Use of the composite polyethylene bubble film according to any one of claims 1 to 5 in packaging and transportation of automobile parts.

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