Multilayer composite packaging material, preparation method and application thereof

Abstract

The present invention relates to the technical field of composite materials, and specifically to a multilayer composite packaging material, a preparation method and its application. The multilayer composite packaging material comprises a surface composite material, a connecting layer and an intermediate layer; the surface composite material and the intermediate layer are connected by a connecting layer; the connecting layer is formed by mixing the following raw materials: 40-60 parts by weight of polymer, 2-5 parts by weight of cooling masterbatch, 2-5 parts by weight of electret masterbatch, 25-40 parts by weight of maleic anhydride graft, and 5-10 parts by weight of connector. The multilayer composite packaging material of the present invention can effectively improve the tensile strength and tear resistance of the multilayer composite die-cutting bag, and can also improve the peel strength. It is applied to handbags with higher impact resistance, can withstand greater external forces, reduce the damage of the bag caused by mechanical pressure during transportation and use, and improve the service life.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a multi-layer composite packaging material, a preparation method and application thereof. Background Art

[0002] The use of handbags brings convenience to people's lives. With the improvement of people's living standards, the pursuit of fashionable quality of life is becoming more and more prominent. Fashionable and functional handbags are becoming more and more popular among young people. At present, most paper-based handbags need to increase the base paper quantity to ensure high load-bearing strength, which makes the handbags hard, difficult to fold, and not convenient to carry out.

[0003] Non-woven fabrics, also known as non-woven fabrics, are made of directional or random fibers. They are moisture-proof, breathable, flexible, lightweight, non-combustible, easy to decompose, non-toxic and non-irritating, colorful, and inexpensive.

[0004] It uses polypropylene (PP material) pellets as raw materials and is produced through a continuous one-step process of high-temperature melting, spinning, laying, and hot pressing and curling. It is mainly used for packaging bags in daily life. The non-woven multi-layer composite material has a long storage time, reduces packaging costs, and reduces manpower, material and medical costs.

[0005] When using non-woven fabrics to make handbags, the traditional preparation process is to stack other materials (such as plastic film, fabric, etc.) on the non-woven fabric. If the film is not reinforced, there will only be inter-fiber forces between the layers of materials that make up the film. The layers of materials are easily separated and peeled off under external forces, which will damage the film and cannot effectively improve the problem of poor mechanical properties of the film. At present, there are the following problems when non-woven fabrics are compounded with other materials (such as plastic film, sheet, paper, etc.). The surface properties, melting points, thicknesses, etc. of different materials vary greatly, resulting in uneven distribution of adhesives or molten materials between layers during the compounding process, forming areas with inconsistent bonding strength. As a result, when the handbag is used, when the force is uneven or the environment changes such as water or heat, the parts with weak bonding are prone to delamination, affecting the overall structural stability and durability of the handbag.

[0006] In the actual application process, the film composed of non-woven fabric and film will be reinforced to solve the above problems, and there are many reinforcement methods. One is to add sticky substances: sticky substances can generally be added to the film in two ways: one is to add adhesives between the non-woven fabric layer and the film layer to play a bonding role and strengthen the combination between the non-woven fabric and the film; the other is to add sticky substances during the preparation process to increase the viscosity between the layers of the composite material, thereby improving the bonding performance between the non-woven fabric and the film. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides a multi-layer composite packaging material, a preparation method and application thereof.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A multilayer composite packaging material comprises a surface composite material, a connecting layer and an intermediate layer; the surface composite material and the intermediate layer are connected via the connecting layer; the thickness of the connecting layer is 8-15 μm; the connecting layer is formed by mixing the following raw materials: 40-60 parts by weight of a polymer, 2-5 parts by weight of a cooling masterbatch, 2-5 parts by weight of an electret masterbatch, 25-40 parts by weight of a maleic anhydride graft, and 5-10 parts by weight of a connector.

[0010] The invention also comprises an inner layer film, wherein the inner layer film is connected by a connecting layer and an intermediate layer.

[0011] Because multilayer composite packaging materials use different materials, each material has different chemical and physical properties, resulting in poor compatibility between them. Different materials also have different heat shrinkage rates, resulting in uneven sealing. At the same time, when there is no connecting layer, different materials may slide between layers, affecting product quality. Therefore, in order to strengthen the connection performance between the layers during the preparation process, a connecting layer with good viscosity is required to effectively connect the layers. An effective connecting layer can ensure a firm bond between the layers to prevent delamination or peeling during processing, transportation or use. Through the connecting layer, the mechanical strength and tear resistance of the composite material can be improved, which is particularly important for applications such as handbags that need to withstand certain mechanical stress. The connecting layer can reduce interlayer sliding and ensure the accuracy of the processing process. The connecting layer can improve the durability of the composite material, so that it can maintain stable performance during long-term use, thereby improving the overall structural stability of the packaging material and reducing the frequency of maintenance and replacement.

[0012] The surface composite material comprises a surface film, a connecting layer and a non-woven fabric, wherein the surface film and the non-woven fabric are connected via the connecting layer, and the surface film is at least one of a biaxially oriented polypropylene film and a polypropylene aluminum-plated film; and the thickness of the connecting layer is 8-15 μm.

[0013] The material of the middle layer is any one of non-woven fabric, paper and plastic sheet.

[0014] The inner layer film is any one of a biaxially oriented polypropylene film and a polypropylene aluminized film.

[0015] The polymer is at least one of polypropylene and polyethylene.

[0016] The preparation method of the linking agent is as follows:

[0017] S1: Hexamethylcyclotrisiloxane, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and tetraethoxydivinyldisiloxane are mixed, trifluoromethanesulfonic acid is added, the mixture is mixed evenly, and heated for reaction to obtain vinyl polysiloxane;

[0018] S2: Methyl methacrylate, isooctyl acrylate, trifluoroethyl methacrylate, acrylic acid, vinyl polysiloxane, 1,2-epoxy-5-hexene and N,N-dimethylformamide are uniformly stirred and ultrasonically dispersed to obtain a microemulsion;

[0019] S3: heating the microemulsion, adding sodium persulfate and stirring to obtain a seed emulsion; then adding the microemulsion and sodium persulfate, heating and stirring to obtain a linker.

[0020] The specific reaction mechanism is as follows: S1 uses hexamethylcyclotrisiloxane, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and tetraethoxydivinyldisiloxane as the main raw materials of the reaction, and trifluoromethanesulfonic acid as the catalyst. Under heating conditions, the siloxane groups contained in hexamethylcyclotrisiloxane, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and tetraethoxydivinyldisiloxane can undergo condensation reaction; S2 uses methyl methacrylate, isooctyl acrylate, trifluoroethyl methacrylate, acrylic acid, vinyl polysiloxane, 1,2-epoxy 5-Hexene is a reaction monomer, N,N-dimethylformamide is a reaction solvent, and ultrasonic dispersion is performed. Ultrasonic dispersion is helpful for uniform dispersion and emulsification of the monomer, and provides a uniform reaction environment for the polymerization reaction to form a microemulsion; S3 heats the microemulsion prepared in S2 to 70-90° C., adds initiator sodium persulfate, and stirs to form a seed emulsion, which helps to control the start and rate of the polymerization reaction; under heating and stirring conditions, the microemulsion and sodium persulfate in S2 are added, the polymerization reaction is heated, and reduced pressure distillation is performed to remove unreacted monomers and initiators to obtain a pure linker.

[0021] Preferably, the preparation method of the linker is as follows:

[0022] S1: 20-30 parts by weight of hexamethylcyclotrisiloxane, 2-5 parts by weight of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and 0.5-1 parts by weight of tetraethoxydivinyldisiloxane are mixed, 0.02-0.2 parts by weight of trifluoromethanesulfonic acid are added, the mixture is mixed evenly, and the mixture is reacted at 60-80° C. and 300-500 rpm for 4-7 hours to obtain vinyl polysiloxane;

[0023] S2: 15-30 parts by weight of methyl methacrylate, 15-30 parts by weight of isooctyl acrylate, 2-6 parts by weight of trifluoroethyl methacrylate, 0.5-2 parts by weight of acrylic acid, 2-6 parts by weight of vinyl polysiloxane, 2-6 parts by weight of 1,2-epoxy-5-hexene and 150-260 parts by weight of N,N-dimethylformamide are uniformly stirred, and ultrasonically dispersed at -4-4°C, ultrasonic power 80-160W, and ultrasonic frequency 30-70kHz for 20-50min to obtain a microemulsion;

[0024] S3: 3-7 parts by weight of the above microemulsion is heated to 70-90° C., 0.1-0.4 parts by weight of sodium persulfate is added, and the mixture is stirred at 400-800 rpm for 30-90 min to obtain a seed emulsion; then 8-14 parts by weight of the above microemulsion and 0.1-0.5 parts by weight of sodium persulfate are added, the mixture is reacted at 70-90° C. and 400-800 rpm for 2-6 h, and the mixture is distilled under reduced pressure to obtain a linker.

[0025] The connector prepared by the present invention can bring the following advantages when used in multi-layer composite packaging materials: (1) The polymer chain formed by the polymerization reaction can penetrate different material layers and introduce organic siloxane molecules containing multiple vinyl groups. The organic siloxane is added during the polymerization of acrylate emulsion, and multiple unsaturated double bonds react with the unsaturated double bonds of the acrylate monomer to form a cross-linked network structure and physical entanglement. This entanglement can significantly improve the bonding force between layers. At the same time, the chemical groups in the connector can form intermolecular forces with each layer of material in the multi-layer composite packaging material. These forces enhance the bonding force between layers, thereby improving the overall mechanical strength of the packaging material; (2) The vinyl polysiloxane structure in the connector can form good adhesion with the surface of the biaxially oriented polypropylene film and the polypropylene aluminum-coated film. This adhesion helps Form a stable interface between the layers, reduce interlayer sliding, and improve tensile strength and tear resistance; (3) The connector can improve the compatibility between different material layers, so that each layer can work together when subjected to external force, rather than bearing the external force alone. It can make the stress distribution more uniform when the multi-layer composite packaging material is subjected to external force, avoiding stress concentration, which helps to improve the impact resistance of the packaging material, thereby improving the durability of the packaging material; Enhance interlayer bonding: in the process of preparing the connector; (4) The siloxane group in the connector can provide additional chemical corrosion resistance, protecting the packaging material from corrosion by chemical substances. At the same time, the addition of the connector can improve the toughness of the multi-layer composite packaging material, so that when it is impacted, the energy can be more effectively absorbed and dispersed, reducing the risk of damage and improving the durability of the packaging material.

[0026] Therefore, the addition of the connector can significantly improve the mechanical strength, durability, tensile strength and tear resistance of the multilayer composite packaging material, thereby improving its impact resistance and reducing the risk of breakage during transportation and use.

[0027] The preparation method of the multi-layer composite packaging material comprises the following steps: weighing the raw materials of the connecting layer according to the weight parts, and then putting the polymer, the cooling masterbatch, the electret masterbatch, the maleic anhydride graft, and the connecting agent into a laminating machine for melting, wherein the temperature of the laminating machine is 180-320°C, and the extrusion strength is 0.2-1MPa, to obtain a molten liquid; putting the molten liquid into the laminating machine for extrusion, wherein the extrusion temperature of the film head is 280-320°C; co-extruding and forming a cast film through the laminating machine, and then sandwiching the cast film between the surface composite material and the middle layer, and between the middle layer and the inner layer film, aligning the edges and corners, hot pressing and bonding, and naturally cooling to obtain the multi-layer composite packaging material.

[0028] Application of the multi-layer composite packaging material in handbags.

[0029] Beneficial effects of the present invention: 1. The present invention provides a multi-layer composite packaging material, a preparation method and its application. The process of the multi-layer composite packaging material of the present invention realizes the composite of five layers of materials, overcoming the shortcomings of single-layer or double-layer coated composite non-woven bag materials on the market that are not durable and easy to break.

[0030] 2. The multi-layer composite packaging material of the present invention is conducive to the texture processing of handbags, can enhance the texture of various leather, cloth and other materials, can be used to make high-end gift bags, and change the problem of single texture of non-woven handbags. The preparation process of the present invention combines the advantages of flatness and stiffness of paper and soft touch and heavy texture of non-woven fabrics.

[0031] 3. The multi-layer composite packaging material of the present invention can effectively improve the mechanical strength and durability of the multi-layer composite die-cutting bag, and enhance its tensile strength and tear resistance. This makes the multi-layer composite die-cutting bag have higher impact resistance, can withstand greater external forces, and reduce the damage caused by mechanical pressure during transportation and use of the bag.

[0032] 4. The multi-layer composite packaging material prepared by the present invention has stronger fastness, is not easy to crack after long-term use, has stronger load-bearing capacity, and improves the service life of the handbag. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 This is a schematic diagram of the structure of the multilayer composite packaging material prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0035] The above content of the present invention is further described in detail below in conjunction with specific implementation modes, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments.

[0036] Introduction of some raw materials in this application:

[0037] Biaxially oriented polypropylene film was purchased from Shanghai Zhaoken New Materials Co., Ltd. with the brand name P405F.

[0038] Polypropylene was purchased from Ningxia Coal Industry Co., Ltd. of China Energy Group, with a grade of 1100N.

[0039] The cooling masterbatch was purchased from Huizhou Yupu Chemical Co., Ltd., model number YP027.

[0040] The electret masterbatch was purchased from Zhejiang Wangyang Polymer Materials Co., Ltd., item number WY1500.

[0041] The maleic anhydride grafted product was purchased from Dongguan Sujia Polymer Raw Materials Co., Ltd., item number N493.

[0042] The non-woven fabric is produced by Sichuan Kaipu Environmental Protection Packaging Products Co., Ltd.

[0043] Example 1

[0044] A multilayer composite packaging material comprises a surface composite material, a connecting layer, an intermediate layer and an inner film; wherein the surface composite material and the intermediate layer are connected via the connecting layer; the intermediate layer and the inner film are connected via the connecting layer; and the thickness of the connecting layer is 10 μm.

[0045] The surface composite material comprises a surface film, a connecting layer and a non-woven fabric, wherein the surface film and the non-woven fabric are connected via the connecting layer, and the surface film is a biaxially stretched polypropylene film.

[0046] The material of the middle layer is non-woven fabric.

[0047] The inner layer film is a biaxially oriented polypropylene film.

[0048] The connecting layer is formed by mixing the following raw materials: 52 parts by weight of polypropylene, 3 parts by weight of cooling masterbatch, 3 parts by weight of electret masterbatch, 35 parts by weight of maleic anhydride grafted material, and 7 parts by weight of connecting agent.

[0049] The preparation method of the linking agent is as follows:

[0050] S1: 25 parts by weight of hexamethylcyclotrisiloxane, 3.5 parts by weight of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and 0.8 parts by weight of tetraethoxydivinyldisiloxane were mixed, 0.1 parts by weight of trifluoromethanesulfonic acid was added, and the mixture was uniformly mixed, and the mixture was reacted at 70° C. and 400 rpm for 5 hours to obtain vinyl polysiloxane;

[0051] S2: 20 parts by weight of methyl methacrylate, 20 parts by weight of isooctyl acrylate, 4 parts by weight of trifluoroethyl methacrylate, 1 part by weight of acrylic acid, 4 parts by weight of vinyl polysiloxane, 4 parts by weight of 1,2-epoxy-5-hexene and 200 parts by weight of N,N-dimethylformamide were uniformly stirred, and ultrasonically dispersed at 0° C., ultrasonic power 100 W, and ultrasonic frequency 40 kHz for 30 min to obtain a microemulsion;

[0052] S3: Take 5 parts by weight of the above microemulsion and heat it to 80°C, add 0.2 parts by weight of sodium persulfate, and stir at 600 rpm for 50 minutes to obtain a seed emulsion; then add 10 parts by weight of the above microemulsion and 0.3 parts by weight of sodium persulfate, react at 80°C and 600 rpm for 4 hours, and distill under reduced pressure to obtain a linker.

[0053] The preparation method of the multi-layer composite packaging material comprises the following steps: weighing the raw materials of the connecting layer according to the weight parts, and then respectively putting the polymer, the cooling masterbatch, the electret masterbatch, the maleic anhydride grafted material and the connecting agent into a laminating machine for melting, wherein the temperature of the laminating machine is 220°C and the extrusion strength is 0.5MPa, to obtain a molten liquid; putting the molten liquid into the laminating machine for extrusion, wherein the extrusion temperature of the film head is 300°C; co-extruding and forming a cast film through the laminating machine, and then sandwiching the cast film between the surface composite material and the middle layer, and between the middle layer and the inner layer film, aligning the edges and corners, hot pressing and bonding, and naturally cooling to obtain the multi-layer composite packaging material.

[0054] Its structural diagram is as follows Figure 1 , Figure 1 The structure shows that the multilayer composite packaging material includes a surface composite material, a connecting layer, an intermediate layer and an inner film which are stacked in sequence; wherein the surface composite material and the intermediate layer are connected by a connecting layer; the intermediate layer and the inner film are connected by a connecting layer; the surface composite material includes a surface film, a connecting layer and a non-woven fabric, the surface film and the non-woven fabric are connected by a connecting layer, the surface film is a biaxially oriented polypropylene film; the material of the intermediate layer is non-woven fabric; the inner film is a biaxially oriented polypropylene film.

[0055] Example 2

[0056] A multi-layer composite packaging material comprises a surface composite material, a connecting layer, an intermediate layer and an inner film; wherein the surface composite material and the intermediate layer are connected via the connecting layer; the intermediate layer and the inner film are connected via the connecting layer; and the thickness of the connecting layer is 8 μm.

[0057] The surface composite material comprises a surface film, a connecting layer and a non-woven fabric, wherein the surface film and the non-woven fabric are connected via the connecting layer, and the surface film is a biaxially stretched polypropylene film.

[0058] The material of the middle layer is non-woven fabric.

[0059] The inner layer film is a biaxially oriented polypropylene film.

[0060] The connecting layer is formed by mixing the following raw materials: 40 parts by weight of polypropylene, 2 parts by weight of cooling masterbatch, 2 parts by weight of electret masterbatch, 25 parts by weight of maleic anhydride grafted material, and 5 parts by weight of connecting agent.

[0061] The preparation method of the linking agent is as follows:

[0062] S1: 20 parts by weight of hexamethylcyclotrisiloxane, 2 parts by weight of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and 0.5 parts by weight of tetraethoxydivinyldisiloxane were mixed, 0.02 parts by weight of trifluoromethanesulfonic acid were added, and the mixture was uniformly mixed, and the mixture was reacted at 60° C. and 300 rpm for 4 hours to obtain vinyl polysiloxane;

[0063] S2: 15 parts by weight of methyl methacrylate, 15 parts by weight of isooctyl acrylate, 2 parts by weight of trifluoroethyl methacrylate, 0.5 parts by weight of acrylic acid, 2 parts by weight of vinyl polysiloxane, 2 parts by weight of 1,2-epoxy-5-hexene and 150 parts by weight of N,N-dimethylformamide were uniformly stirred, and ultrasonically dispersed at -4°C, an ultrasonic power of 80 W and an ultrasonic frequency of 30 kHz for 20 min to obtain a microemulsion;

[0064] S3: Take 3 parts by weight of the above microemulsion and heat it to 70°C, add 0.1 parts by weight of sodium persulfate, and stir at 400 rpm for 30 minutes to obtain a seed emulsion; then add 8 parts by weight of the above microemulsion and 0.1 parts by weight of sodium persulfate, react at 70°C and 400 rpm for 2 hours, and distill under reduced pressure to obtain a linker.

[0065] The preparation method of the multi-layer composite packaging material comprises the following steps: weighing the raw materials of the connecting layer according to the weight parts, and then putting the polymer, the cooling masterbatch, the electret masterbatch, the maleic anhydride grafted material and the connecting agent into a laminating machine for melting, wherein the temperature of the laminating machine is 180°C and the extrusion strength is 0.2MPa, to obtain a molten liquid, and putting the molten liquid into the laminating machine for extrusion, wherein the extrusion temperature of the film head is 280°C; co-extruding and forming a cast film through the laminating machine, and then sandwiching the cast film between the surface composite material and the middle layer, and between the middle layer and the inner film, aligning the edges and corners, hot pressing and bonding, and naturally cooling to obtain the multi-layer composite packaging material.

[0066] Example 3

[0067] A multilayer composite packaging material comprises a surface composite material, a connecting layer, an intermediate layer and an inner film; wherein the surface composite material and the intermediate layer are connected via the connecting layer; the intermediate layer and the inner film are connected via the connecting layer; and the thickness of the connecting layer is 15 μm.

[0068] The surface composite material comprises a surface film, a connecting layer and a non-woven fabric, wherein the surface film and the non-woven fabric are connected via the connecting layer, and the surface film is a biaxially stretched polypropylene film.

[0069] The material of the middle layer is non-woven fabric.

[0070] The inner layer film is a biaxially oriented polypropylene film.

[0071] The connecting layer is formed by mixing the following raw materials: 60 parts by weight of polypropylene, 5 parts by weight of cooling masterbatch, 5 parts by weight of electret masterbatch, 40 parts by weight of maleic anhydride grafted material, and 10 parts by weight of connecting agent.

[0072] The preparation method of the linking agent is as follows:

[0073] S1: 30 parts by weight of hexamethylcyclotrisiloxane, 5 parts by weight of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and 1 part by weight of tetraethoxydivinyldisiloxane were mixed, 0.2 parts by weight of trifluoromethanesulfonic acid were added, and the mixture was uniformly mixed, and the mixture was reacted at 80° C. and 500 rpm for 7 hours to obtain vinyl polysiloxane;

[0074] S2: 30 parts by weight of methyl methacrylate, 30 parts by weight of isooctyl acrylate, 6 parts by weight of trifluoroethyl methacrylate, 2 parts by weight of acrylic acid, 6 parts by weight of vinyl polysiloxane, 6 parts by weight of 1,2-epoxy-5-hexene and 260 parts by weight of N,N-dimethylformamide were uniformly stirred, and ultrasonically dispersed at 4° C., ultrasonic power 160 W, and ultrasonic frequency 70 kHz for 50 min to obtain a microemulsion;

[0075] S3: Take 7 parts by weight of the above microemulsion and heat it to 90°C, add 0.4 parts by weight of sodium persulfate, and stir at 800 rpm for 90 minutes to obtain a seed emulsion; then add 14 parts by weight of the above microemulsion and 0.5 parts by weight of sodium persulfate, react at 90°C and 800 rpm for 6 hours, and distill under reduced pressure to obtain a linker.

[0076] The preparation method of the multi-layer composite packaging material comprises the following steps: weighing the raw materials of the connecting layer according to the weight parts, and then respectively putting the polymer, the cooling masterbatch, the electret masterbatch, the maleic anhydride grafted material and the connecting agent into a laminating machine for melting, wherein the temperature of the laminating machine is 320°C and the extrusion strength is 1MPa, to obtain a molten liquid; putting the molten liquid into the laminating machine for extrusion, wherein the extrusion temperature of the film head is 320°C; co-extruding and forming a cast film through the laminating machine, and then sandwiching the cast film between the surface composite material and the middle layer, and between the middle layer and the inner film, aligning the edges and corners, hot pressing and bonding, and naturally cooling to obtain the multi-layer composite packaging material.

[0077] Comparative Example 1

[0078] A multilayer composite packaging material comprises a surface composite material, a connecting layer, an intermediate layer and an inner film; wherein the surface composite material and the intermediate layer are connected via the connecting layer; the intermediate layer and the inner film are connected via the connecting layer; and the thickness of the connecting layer is 10 μm.

[0079] The surface composite material comprises a surface film, a connecting layer and a non-woven fabric, wherein the surface film and the non-woven fabric are connected via the connecting layer, and the surface film is a biaxially stretched polypropylene film.

[0080] The material of the middle layer is non-woven fabric.

[0081] The inner layer film is a biaxially oriented polypropylene film.

[0082] The connecting layer is formed by mixing the following raw materials: 52 parts by weight of polypropylene, 3 parts by weight of cooling masterbatch, 3 parts by weight of electret masterbatch, and 35 parts by weight of maleic anhydride grafted material.

[0083] The preparation method of the multi-layer composite packaging material comprises the following steps: weighing the raw materials of the connecting layer according to the weight parts, and then respectively putting the polymer, the cooling masterbatch, the electret masterbatch, the maleic anhydride grafted material and the connecting agent into a laminating machine for melting, wherein the temperature of the laminating machine is 220°C and the extrusion strength is 0.5MPa, to obtain a molten liquid; putting the molten liquid into the laminating machine for extrusion, wherein the extrusion temperature of the film head is 300°C; co-extruding and forming a cast film through the laminating machine, and then sandwiching the cast film between the surface composite material and the middle layer, and between the middle layer and the inner layer film, aligning the edges and corners, hot pressing and bonding, and naturally cooling to obtain the multi-layer composite packaging material.

[0084] Comparative Example 2

[0085] A multilayer composite packaging material comprises a surface composite material, a connecting layer, an intermediate layer and an inner film; wherein the surface composite material and the intermediate layer are connected via the connecting layer; the intermediate layer and the inner film are connected via the connecting layer; and the thickness of the connecting layer is 10 μm.

[0086] The surface composite material comprises a surface film, a connecting layer and a non-woven fabric, wherein the surface film and the non-woven fabric are connected via the connecting layer, and the surface film is a biaxially stretched polypropylene film.

[0087] The material of the middle layer is non-woven fabric.

[0088] The inner layer film is a biaxially oriented polypropylene film.

[0089] The connecting layer is formed by mixing the following raw materials: 52 parts by weight of polypropylene, 3 parts by weight of cooling masterbatch, 3 parts by weight of electret masterbatch, 35 parts by weight of maleic anhydride grafted material, and 7 parts by weight of connecting agent.

[0090] The preparation method of the linker is as follows: 25 parts by weight of hexamethylcyclotrisiloxane, 3.5 parts by weight of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and 0.8 parts by weight of tetraethoxydivinyldisiloxane are mixed, 0.1 parts by weight of trifluoromethanesulfonic acid are added, the mixture is mixed evenly, and the mixture is reacted at 70° C. and 400 rpm for 5 hours to obtain a linker.

[0091] The preparation method of the multi-layer composite packaging material comprises the following steps: weighing the raw materials of the connecting layer according to the weight parts, and then respectively putting the polymer, the cooling masterbatch, the electret masterbatch, the maleic anhydride grafted material and the connecting agent into a laminating machine for melting, wherein the temperature of the laminating machine is 220°C and the extrusion strength is 0.5MPa, to obtain a molten liquid; putting the molten liquid into the laminating machine for extrusion, wherein the extrusion temperature of the film head is 300°C; co-extruding and forming a cast film through the laminating machine, and then sandwiching the cast film between the surface composite material and the middle layer, and between the middle layer and the inner layer film, aligning the edges and corners, hot pressing and bonding, and naturally cooling to obtain the multi-layer composite packaging material.

[0092] Comparative Example 3

[0093] A multilayer composite packaging material comprises a surface composite material, a connecting layer, an intermediate layer and an inner film; wherein the surface composite material and the intermediate layer are connected via the connecting layer; the intermediate layer and the inner film are connected via the connecting layer; and the thickness of the connecting layer is 10 μm.

[0094] The surface composite material comprises a surface film, a connecting layer and a non-woven fabric, wherein the surface film and the non-woven fabric are connected via the connecting layer, and the surface film is a biaxially stretched polypropylene film.

[0095] The material of the middle layer is non-woven fabric.

[0096] The inner layer film is a biaxially oriented polypropylene film.

[0097] The connecting layer is formed by mixing the following raw materials: 52 parts by weight of polypropylene, 3 parts by weight of cooling masterbatch, 3 parts by weight of electret masterbatch, 35 parts by weight of maleic anhydride grafted material, and 7 parts by weight of connecting agent.

[0098] The preparation method of the linking agent is as follows:

[0099] S1: 20 parts by weight of methyl methacrylate, 20 parts by weight of isooctyl acrylate, 4 parts by weight of trifluoroethyl methacrylate, 1 part by weight of acrylic acid, 4 parts by weight of tetraethoxydivinyldisiloxane, 4 parts by weight of 1,2-epoxy-5-hexene and 200 parts by weight of N,N-dimethylformamide were stirred uniformly, and ultrasonically dispersed at 0° C., ultrasonic power of 100 W and ultrasonic frequency of 40 kHz for 30 min to obtain a microemulsion;

[0100] S2: Take 5 parts by weight of the above microemulsion and heat it to 80°C, add 0.2 parts by weight of sodium persulfate, and stir at 600 rpm for 50 minutes to obtain a seed emulsion; then add 10 parts by weight of the above microemulsion and 0.3 parts by weight of sodium persulfate, react at 80°C and 600 rpm for 4 hours, and distill under reduced pressure to obtain a linker.

[0101] The preparation method of the multi-layer composite packaging material comprises the following steps: weighing the raw materials of the connecting layer according to the weight parts, and then respectively putting the polymer, the cooling masterbatch, the electret masterbatch, the maleic anhydride grafted material and the connecting agent into a laminating machine for melting, wherein the temperature of the laminating machine is 220°C and the extrusion strength is 0.5MPa, to obtain a molten liquid; putting the molten liquid into the laminating machine for extrusion, wherein the extrusion temperature of the film head is 300°C; co-extruding and forming a cast film through the laminating machine, and then sandwiching the cast film between the surface composite material and the middle layer, and between the middle layer and the inner layer film, aligning the edges and corners, hot pressing and bonding, and naturally cooling to obtain the multi-layer composite packaging material.

[0102] Test Example 1

[0103] Tensile strength test: The tensile properties of the multilayer composite packaging materials prepared in each embodiment and comparative example were tested in accordance with the national standard GB / T1040.2-2022 "Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics". Five groups were tested in parallel, and the average value was taken. The results are shown in Table 1.

[0104] Right-angle tear strength: tested according to QB / T1130-1991 "Test method for right-angle tear properties of plastics", each group was tested 5 times, and the average value was taken. The results are shown in Table 1.

[0105] Table 1 Mechanical properties test results of multilayer composite packaging materials

[0106]

[0107] Test Example 2

[0108] Peel strength test: With reference to the national standard GB / T10004-2008 "Dry-process lamination and extrusion lamination of plastic films and bags for packaging", the peel strength test was carried out on the multilayer composite packaging materials prepared in the above Example 1 and Comparative Examples 1-3. Each group was tested 4 times and the average value was taken. The results are shown in Table 2.

[0109] Table 2 Peel strength test results of multilayer composite packaging materials

[0110]

[0111] From the above results, it can be seen that the multilayer composite packaging material prepared by the present invention has good mechanical strength and durability, and enhances its tensile strength and tear resistance. This makes the multilayer composite die-cut bag have higher impact resistance, can withstand greater external forces, and reduce the damage of the bag caused by mechanical pressure during transportation and use. The specific reason is that the connector prepared by the present invention can be used in multilayer composite packaging materials to bring the following advantages: (1) The polymer chain formed by the polymerization reaction can penetrate different material layers, introduce organic siloxane molecules containing multiple vinyl groups, and add organic siloxanes during the polymerization of acrylic ester emulsions. Multiple unsaturated double bonds react with the unsaturated double bonds of acrylic ester monomers to form a cross-linked network structure and form physical entanglement. This entanglement can significantly improve the bonding force between layers. At the same time, the chemical groups in the connector can form intermolecular forces with each layer of material in the multilayer composite packaging material. These forces enhance the bonding force between layers, thereby improving the overall mechanical strength of the packaging material; (2) The vinyl polysiloxane structure in the connector can form good adhesion with the surface of the biaxially oriented polypropylene film and the polypropylene aluminum-coated film. This adhesion (3) The connector can improve the compatibility between different material layers, so that each layer can work together when subjected to external force, rather than bearing the external force alone. It can make the stress distribution more uniform when the multi-layer composite packaging material is subjected to external force, avoiding stress concentration, which helps to improve the impact resistance of the packaging material, thereby improving the durability of the packaging material; Enhance interlayer bonding: in the process of preparing the connector; (4) The siloxane group in the connector can provide additional chemical corrosion resistance, protecting the packaging material from corrosion by chemical substances. At the same time, the addition of the connector can improve the toughness of the multi-layer composite packaging material, so that when it is impacted, the energy can be more effectively absorbed and dispersed, reducing the risk of damage and improving the durability of the packaging material.

[0112] Therefore, the addition of the connector can significantly improve the mechanical strength, durability, tensile strength and tear resistance of the multilayer composite packaging material, thereby improving its impact resistance and reducing the risk of breakage during transportation and use.

Claims

1. A multi-layer composite packaging material, comprising a surface composite material, a connecting layer, and an intermediate layer; characterized in that: The surface composite material and the middle layer are connected by a connecting layer; the connecting layer is made of a mixture of the following raw materials: 40-60 parts by weight of polymer, 2-5 parts by weight of cooling masterbatch, 2-5 parts by weight of electret masterbatch, 25-40 parts by weight of maleic anhydride grafted material, and 5-10 parts by weight of connecting agent; The preparation method of the linking agent is as follows: S1: 20-30 parts by weight of hexamethylcyclotrisiloxane, 2-5 parts by weight of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and 0.5-1 parts by weight of tetraethoxydivinyldisiloxane are mixed, 0.02-0.2 parts by weight of trifluoromethanesulfonic acid are added, the mixture is mixed evenly, and the mixture is reacted at 60-80° C. and 300-500 rpm for 4-7 hours to obtain vinyl polysiloxane; S2: 15-30 parts by weight of methyl methacrylate, 15-30 parts by weight of isooctyl acrylate, 2-6 parts by weight of trifluoroethyl methacrylate, 0.5-2 parts by weight of acrylic acid, 2-6 parts by weight of vinyl polysiloxane, 2-6 parts by weight of 1,2-epoxy-5-hexene and 150-260 parts by weight of N,N-dimethylformamide are uniformly stirred, and ultrasonically dispersed at -4-4°C, ultrasonic power 80-160W, and ultrasonic frequency 30-70kHz for 20-50min to obtain a microemulsion; S3: 3-7 parts by weight of the above microemulsion is heated to 70-90° C., 0.1-0.4 parts by weight of sodium persulfate is added, and the mixture is stirred at 400-800 rpm for 30-90 min to obtain a seed emulsion; then 8-14 parts by weight of the above microemulsion and 0.1-0.5 parts by weight of sodium persulfate are added, the mixture is reacted at 70-90° C. and 400-800 rpm for 2-6 h, and the mixture is distilled under reduced pressure to obtain a linker.

2. The multilayer composite packaging material according to claim 1, characterized in that: The invention also comprises an inner layer film, wherein the inner layer film is connected by a connecting layer and an intermediate layer.

3. The multilayer composite packaging material according to claim 1, characterized in that: The surface composite material comprises a surface film, a connecting layer and a non-woven fabric, wherein the surface film and the non-woven fabric are connected via the connecting layer, and the surface film is at least one of a biaxially oriented polypropylene film and a polypropylene aluminum-plated film.

4. The multilayer composite packaging material according to claim 1, characterized in that: The material of the middle layer is any one of non-woven fabric, paper and plastic sheet.

5. The multilayer composite packaging material according to claim 2, characterized in that: The inner layer film is any one of a biaxially oriented polypropylene film and a polypropylene aluminized film.

6. The multilayer composite packaging material according to claim 1, characterized in that: The polymer is at least one of polypropylene and polyethylene.

7. Use of the multilayer composite packaging material according to any one of claims 1 to 6 in a handbag.

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