Preparation process of a paper-based protective inflatable bubble bag composite film and its product

Abstract

This application relates to the technical field of inflatable bubble bag composite film processing. More specifically, it relates to a preparation process and product of a paper-based protective inflatable bubble bag composite film, including the following preparation steps: S1. Coat a waterproof and airtight glue on the surface of the substrate, dry it to form a waterproof and airtight layer, and obtain a waterproof and airtight composite film. The waterproof and airtight glue is prepared by mixing polyvinyl alcohol, polyurethane-modified silicone, water-soluble chitosan, water-soluble acrylic resin, isooctyl acrylate, crosslinking agent, ethanol, and water; S2. Press the kraft paper and the waterproof and airtight composite film together at a pressing temperature of 140-150 °C and a pressing pressure of 12-16 MPa, so that the kraft paper and the waterproof and airtight layer adhere to each other to obtain a kraft paper composite film; S3. Tear off the substrate layer; S4. Coat a heat-sealing glue on the surface of the waterproof and airtight layer and dry it to obtain a paper-based protective inflatable bubble bag composite film. The paper-based protective inflatable bubble bag composite film prepared by the above process has good waterproof and airtight performance.

Description

Technical Field

[0001] The present application relates to the technical field of processing of inflatable bubble bag composite films, and more specifically, to a preparation process and product of a paper-based protective inflatable bubble bag composite film. Background Art

[0002] Express buffer bubble bags are a new type of packaging material, mainly using the gas inside the bubble bags to play a buffering and protective role, usually prepared from plastics. With the development of the express delivery business, the quantity of express buffer bubble bags required has also increased significantly, resulting in more waste plastics and more serious plastic pollution. In order to improve the problem of plastic pollution of express buffer bubble bags, paper-based buffer bubble bags are used to replace some plastic buffer bags.

[0003] Currently, the existing paper-based buffer bubble bags are prepared by the following method: A waterproof and airtight layer is formed by coating a functional glue on the surface of kraft paper to obtain a kraft paper composite film, and then the kraft paper composite film is made into a paper-based buffer bubble bag. In the actual use process, it will be found that the gas in the paper-based buffer bubble bag will slowly release over time, resulting in a reduction in the buffering performance of the paper-based buffer bubble bag.

[0004] The main reason is that: the kraft paper is breathable and its surface is not smooth, resulting in uneven glue coating, so that the glue layer and the kraft paper layer cannot be completely adhered, and the gas in the paper-based buffer bubble bag will gradually be released into the external environment over time. Although this process is slow, it will cause the gas pressure inside the bubble bag to decrease, thereby affecting its buffering performance. When the gas is released to a certain extent, the buffering effect of the paper-based buffer bubble bag will be greatly reduced and it can no longer provide sufficient protection for the items in the package. Summary of the Invention

[0005] In order to improve the adhesion stability between the kraft paper layer and the waterproof and airtight layer and improve the airtight effect of the kraft composite film, the present application provides a preparation process and product of a paper-based protective inflatable bubble bag composite film.

[0006] In the first aspect, the present application provides a preparation process of a paper-based protective inflatable bubble bag composite film, adopting the following technical scheme:

[0007] A preparation process of a paper-based protective inflatable bubble bag composite film includes the following preparation steps:

[0008] S1. Coat a waterproof and airtight glue on the surface of the substrate, dry it to form a waterproof and airtight layer, and obtain a waterproof and airtight composite film. The waterproof and airtight glue is prepared by mixing polyvinyl alcohol, polyurethane-modified silicone, water-soluble chitosan, water-soluble acrylic resin, isooctyl acrylate, cross-linking agent, ethanol, and water;

[0009] S2. Press the kraft paper and the waterproof and airtight composite film together at a pressing temperature of 140 - 150 °C and a pressing pressure of 12 - 16 MPa, so that the kraft paper and the waterproof and airtight layer adhere to each other to obtain the kraft paper composite film;

[0010] S3. Tear off the substrate layer;

[0011] S4. Coat the surface of the waterproof and airtight layer with heat-sealing glue and dry it to obtain the paper protective inflatable bubble bag composite film.

[0012] By adopting the above technical solution, the prepared paper protective inflatable bubble bag composite film has good waterproof and airtight performance. By first coating a waterproof and airtight glue composed of a variety of components on the substrate and drying it to form a waterproof and airtight layer, the uniformity and density of the waterproof and airtight layer are ensured. Then, pressing it with kraft paper solves the problem of poor adhesion and easy air leakage caused by uneven glue coating. Compared with the original solution of directly coating functional glue on kraft paper, it is more compact and uniform, and can effectively reduce the release of gas through the breathability of kraft paper. Pressing the kraft paper and the waterproof and airtight composite film under high temperature and high pressure conditions makes the adhesion between the two more firm, reduces the possibility of gas leakage, and also enhances the overall structural strength of the bubble bag.

[0013] The waterproof and airtight glue not only has excellent waterproof performance, but also can effectively isolate gas penetration, greatly slowing down the release rate of gas inside the bubble bag, thus maintaining the long-term buffering effect of the bubble bag. In this application, the waterproof and airtight glue prepared from composite materials such as polyvinyl alcohol, polyurethane-modified silicone, water-soluble chitosan, water-soluble acrylic resin, and isooctyl acrylate forms a dense waterproof and airtight layer on the surface of the substrate. Among them, under the combined action of polyurethane-modified silicone, acrylic resin and isooctyl acrylate, the composite film is given excellent waterproof performance and can effectively block the penetration of moisture; due to the sealing property of polyurethane-modified silicone and the role of the cross-linking agent, the composite film has excellent airtight performance and can prevent gas leakage; polyvinyl alcohol and water-soluble chitosan enhance the adhesion of the glue to the substrate and at the same time form a uniform and dense film layer. The cross-linking agent is used to promote the cross-linking reaction between resin molecules and enhance the stability and adhesion of the glue.

[0014] By precisely controlling the pressing temperature and pressure, a better adhesion effect is achieved between the kraft paper and the waterproof and airtight layer, which not only reduces the possibility of gas released through the tiny gaps between the kraft paper and the glue layer, but also enhances the overall structural strength of the composite film, improving the durability and reliability of the bubble bag.

[0015] The heat-sealing glue has good adhesion and heat-sealing performance, and can achieve the sealing of the bubble bag by heating during the subsequent bag-making process. After coating the heat-sealing glue on the surface of the waterproof and airtight layer and drying it, a paper protective inflatable bubble bag composite film with excellent sealing performance is obtained.

[0016] Preferably, the weight percentages of the raw materials used to prepare the waterproof and airtight glue are as follows:

[0017] Polyvinyl alcohol 10 - 20%

[0018] Polyurethane - modified silicone 5 - 8%

[0019] Water - soluble chitosan 3 - 4%

[0020] Water - soluble acrylic resin 10 - 15%

[0021] 2 - ethylhexyl acrylate 10 - 15%

[0022] Cross - linker 0.5 - 1%

[0023] Ethanol 15 - 25%

[0024] The balance is water.

[0025] By adopting the above - mentioned technical solution, the weight of the raw materials used to prepare the waterproof and airtight glue is optimized, so that the viscosity of the waterproof and airtight glue is moderate, it is easy to coat, has good film - forming property, and at the same time ensures that the formed film layer has excellent waterproof and airtight performance, adhesion, weather resistance and water resistance, which is beneficial to the lamination with kraft paper and ensures that gas does not leak.

[0026] Preferably, the waterproof and airtight glue is prepared by the following method:

[0027] Mix water and ethanol, then add water - soluble chitosan, water - soluble acrylic resin and polyvinyl alcohol, stir until completely dissolved, and then add polyurethane - modified silicone, 2 - ethylhexyl acrylate and cross - linker and stir evenly to obtain the waterproof and airtight glue.

[0028] By adopting the above - mentioned technical solution, it helps to form a uniform mixing system

[0029] Preferably, the wet coating amount of the waterproof and airtight glue is 30 - 40 g / m 2 .

[0030] At this wet coating amount, the waterproof and airtight glue can form a relatively uniform and continuous thin film, effectively blocking the penetration of moisture and gas, and improving the waterproof and gas - permeability of the composite film of the paper - based protective inflated bubble bag. Too little coating amount may lead to an incomplete film layer, affecting the waterproof and airtight effect; while too much coating amount may cause waste and even affect the drying speed and performance of the film layer.

[0031] Preferably, in step S1, the drying temperature is 120 - 130 °C and the speed is 60 - 70 m / min.

[0032] By adopting the above technical solutions, the evaporation of ethanol and water can be accelerated, the formation of the film can be promoted, and the rapid drying of the glue and surface hardening caused by too high temperature, which may lead to defects such as cracks and blisters on the surface of the film layer, can be avoided. At the same time, the low production efficiency caused by too slow drying speed at too low temperature can also be prevented. A speed of 60 - 70 m / min is relatively moderate, which can ensure that the film layer is uniformly and fully cured during the drying process. Too fast drying speed will cause the surface of the film layer to harden rapidly while the internal solvent has not been completely evaporated, resulting in problems such as internal stress or cracking, ultimately affecting the waterproof and airtight effect.

[0033] Preferably, the heat-sealing glue is prepared from the following raw materials by weight percentage:

[0034] Polyvinyl alcohol 15 - 20%

[0035] Polyurethane-modified silicone 5 - 8%

[0036] Ethylene-vinyl acetate copolymer emulsion 5 - 9%

[0037] Curing agent 0.5 - 1%

[0038] Ethanol 10 - 20%

[0039] The balance is water.

[0040] By adopting the above technical solutions, the prepared heat-sealing glue has excellent film-forming property, adhesiveness, water resistance and weather resistance. It can be rapidly cured during the heat-sealing process to form a stable and reliable sealing layer, effectively preventing the internal leakage of the bubble bag. Polyvinyl alcohol can ensure that the glue forms a continuous and uniform film layer after drying, while maintaining sufficient flexibility and elasticity to adapt to the deformation of the bubble bag during transportation and use. Polyurethane-modified silicone can effectively improve the stability of the glue in harsh environments such as high temperature and high humidity, preventing the glue from aging, cracking or losing adhesiveness. At the same time, polyurethane-modified silicone also has certain lubricity, which helps to improve the fluidity of the glue during the coating process and reduce the generation of defects such as bubbles and pinholes. At the same time, due to the presence of polyvinyl alcohol and polyurethane-modified silicone in the heat-sealing glue, it is beneficial to the stable connection between the heat-sealing layer and the waterproof and airtight layer, preventing the two from separating during use. Adding an appropriate amount of EVA emulsion to the heat-sealing glue can make the glue form a softer and more elastic film layer after curing, which is more suitable for the morphological changes of the bubble bag and prevents the bubble bag from leaking due to deformation. The curing agent promotes the cross-linking reaction of the polymer components in the glue under heating conditions to form a stable three-dimensional network structure.

[0041] Preferably, the wet coating amount of the heat-sealing glue is 5 - 10 g / m 2 .

[0042] By adopting the above technical solutions, the heat-sealing glue can be evenly coated on the surface of the waterproof and airtight layer, forming good adhesion with the waterproof and airtight layer to ensure the sealing performance of the bubble bag. At the same time, within the range of the coating wet weight, the viscosity of the heat-sealing glue is moderate, which is easy to be evenly coated by a coating machine or other coating equipment, reducing waste and defects during the coating process.

[0043] Preferably, before step S4, polyurethane glue is coated on the surface of the waterproof and airtight layer and dried to obtain a polyurethane composite film.

[0044] By adopting the above technical solutions, the folding resistance and toughness of the paper-based protective inflatable bubble bag composite film are increased. Polyurethane glue has excellent strength and toughness. After being coated on the surface of the waterproof and airtight layer, it can endow the composite film with better flexibility and strength, so that when the bubble bag is repeatedly folded or bent, it is not easy to be damaged or cracked, can adapt to various shapes and sizes of packaged items, and at the same time, when being squeezed or impacted, it can better absorb and disperse stress to protect the internal items from damage. At the same time, the polyurethane glue is tightly combined with the waterproof and airtight layer to form a strong protective layer. This protective layer can effectively resist the tearing of external mechanical forces, prevent the bubble bag from being torn due to external forces during transportation and use, and can be used for large and fragile express deliveries.

[0045] Preferably, the coating wet weight of the polyurethane glue is 10 - 15 g / m 2 。

[0046] By adopting the above technical solutions, the coating amount of the polyurethane glue is optimized, so that the polyurethane glue can form a continuous coating on the surface of the waterproof and airtight glue, ensuring the toughness and folding resistance of the paper-based protective inflatable bubble bag composite film. Excessive coating amount may lead to glue waste and prolonged drying time, while too little coating amount may not ensure good adhesion and sealing performance.

[0047] In the second aspect, the present application provides a paper-based protective inflatable bubble bag composite film, adopting the following technical solutions:

[0048] A paper-based protective inflatable bubble bag composite film, which is prepared by the preparation process of the paper-based protective inflatable bubble bag composite film described in the first aspect.

[0049] By adopting the above technical solutions, the prepared paper-based protective inflatable bubble bag composite film has good waterproof and airtight performance, and at the same time, can also have good toughness, making it not easy to be damaged during use.

[0050] In summary, the present application has the following beneficial effects:

[0051] 1. Excellent waterproof and gas-barrier performance: Through the use of waterproof and gas-barrier glue and the hot pressing process under high temperature and pressure, the composite film can effectively block the penetration of moisture and gas, ensuring the stability of the gas pressure inside the bubble bag.

[0052] 2. Good adhesion strength: The tight adhesion between the kraft paper and the waterproof and gas-barrier layer ensures the overall strength and durability of the composite film.

[0053] 3. Excellent sealing performance: The use of heat-sealing glue enables the bubble bag to maintain a good sealed state after inflation, preventing gas leakage and the intrusion of external pollutants.

[0054] 4. Durable buffering effect: Due to the enhanced waterproof and gas-barrier performance and the stable gas pressure, the bubble bag made of the composite film can maintain excellent buffering effect for a long time, providing sufficient protection for the items inside the package. Specific implementation method

[0055] The water-soluble acrylic resin was purchased from Guangdong Dingxin Polymer Technology Co., Ltd., with the brand of Mitsubishi of Japan and the model of BR116.

[0056] The polyurethane-modified silicone was purchased from Shanghai Shuaike Chemical Co., Ltd., with the model of SK7808.

[0057] The polyvinyl alcohol was purchased from Dongguan Yingxiang Plastic Raw Materials Co., Ltd., with the brand of Kuraray of Japan and the model of AX-600.

[0058] The ethylene-vinyl acetate copolymer emulsion was purchased from Shandong New Kinetic Energy Chemical Co., Ltd., with the model of 707.

[0059] Preparation example

[0060] Preparation example 1

[0061] A waterproof and gas-barrier glue was prepared by the following method:

[0062] Mix 220 g of water and 250 g of ethanol, then add 40 g of water-soluble chitosan, 150 g of water-soluble acrylic resin and 100 g of polyvinyl alcohol, stir until completely dissolved, and then add 80 g of polyurethane-modified silicone, 150 g of isooctyl acrylate and 10 g of cross-linking agent (toluene diisocyanate) and stir evenly to obtain the waterproof and gas-barrier glue.

[0063] The differences between Preparation examples 2-3 and Preparation example 1 are that the types, dosages of some raw materials and experimental parameters for preparing the waterproof and gas-barrier glue are different. The specific differences are shown in Table 1:

[0064] Table 1 Types, dosages of raw materials and experimental parameters for preparing the waterproof and gas-barrier glue in Preparation examples 1-3

[0065]

[0066]

[0067] Preparation Example 4

[0068] A heat-sealing glue is prepared by the following method:

[0069] 100 g of polyvinyl alcohol, 80 g of polyurethane-modified silicone, 90 g of ethylene-vinyl acetate copolymer emulsion, 10 g of curing agent (tetraethyl orthosilicate), 200 g of ethanol and 520 g of water are stirred evenly.

[0070] The differences between Preparation Examples 5-6 and Preparation Example 5 are that the types, dosages of some raw materials for preparing the heat-sealing glue and the experimental parameters are different. The specific differences are shown in Table 2:

[0071] Table 2 Types, dosages of raw materials for preparing the heat-sealing glue in Preparation Examples 4-6 and experimental parameters

[0072]

[0073] Preparation of Comparative Examples

[0074] Preparation of Comparative Example 1

[0075] A waterproof and airtight glue. The difference between this preparation of the comparative example and Preparation Example 1 is that polyvinyl pyrrolidone is used instead of polyvinyl alcohol.

[0076] Polyvinyl pyrrolidone is purchased from Jinan Pengduo Trading Co., Ltd., and the model is 30.

[0077] Preparation of Comparative Example 2

[0078] A waterproof and airtight glue. The difference between this preparation of the comparative example and Preparation Example 1 is that epoxy resin is used instead of polyurethane-modified silicone.

[0079] Epoxy resin is purchased from Wuhan Mengqi Technology Co., Ltd., and the model is TL-017481.

[0080] Preparation of Comparative Example 3

[0081] A waterproof and airtight glue. The difference between this preparation of the comparative example and Preparation Example 1 is that carboxymethyl cellulose is used instead of water-soluble chitosan.

[0082] Preparation of Comparative Example 4

[0083] A waterproof and airtight glue. The difference between this preparation of the comparative example and Preparation Example 1 is that water-soluble epoxy resin is used instead of water-soluble acrylic resin.

[0084] Water-soluble epoxy resin is purchased from Jining Fangyu Chemical Co., Ltd., and the brand is J-990.

[0085] Example

[0086] Example 1

[0087] A paper protective inflatable bubble bag composite film is prepared by the following method:

[0088] S1. Coat the waterproof and airtight glue from Preparation Example 1 on the surface of the substrate. The wet coating amount of the waterproof and airtight glue is 30 g / m2, and then dry it. The drying temperature is 120 °C and the speed is 60 m / min to form a waterproof and airtight layer, obtaining a waterproof and airtight composite film;

[0089] S2. Press the kraft paper and the waterproof and airtight composite film together. The pressing temperature is 140 °C and the pressing pressure is 12 MPa, so that the kraft paper and the waterproof and airtight layer adhere to each other, obtaining a kraft paper composite film;

[0090] S3. Tear off the substrate layer;

[0091] S4. Coat the heat-sealing glue from Preparation Example 4 on the surface of the waterproof and airtight layer. The wet coating amount of the heat-sealing glue is 5 g / m2, and then dry it at a drying temperature of 120 °C and a speed of 20 m / min to obtain the paper protective inflatable bubble bag composite film.

[0092] Examples 2-3 are different from Example 1 in that the experimental parameters for preparing the paper protective inflatable bubble bag composite film are different. The specific differences are shown in Table 3:

[0093] Table 3 Experimental parameters for preparing the paper protective inflatable bubble bag composite film in Examples 1-3

[0094]

[0095] Example 4

[0096] A paper protective inflatable bubble bag composite film. The difference between this example and Example 1 is that the waterproof and airtight glue comes from Preparation Example 2 and the heat-sealing glue comes from Preparation Example 5.

[0097] Example 5

[0098] A paper protective inflatable bubble bag composite film. The difference between this example and Example 1 is that the waterproof and airtight glue comes from Preparation Example 3 and the heat-sealing glue comes from Preparation Example 6.

[0099] Example 6

[0100] A paper protective inflatable bubble bag composite film. The difference between this example and Example 1 is that the heat-sealing glue is commercially available.

[0101] The heat-sealing glue was purchased from Dongguan Yongshengfa Plastic Co., Ltd., and the brand is Dow EAA3003.

[0102] Example 7

[0103] A paper protective inflatable bubble bag composite film. The difference between this example and Example 1 is that before step S4, polyurethane glue is coated on the surface of the waterproof and airtight layer and dried to obtain a polyurethane composite film. The wet coating amount of the polyurethane glue is 10 g / m 2 .

[0104] The polyurethane glue was purchased from Shanghai Bolinuo New Material Technology Co., Ltd., and the model is 5715B.

[0105] Example 8

[0106] A paper protective inflatable bubble bag composite film. The difference between this example and Example 1 is that before step S4, polyurethane glue is coated on the surface of the waterproof and airtight layer and dried to obtain a polyurethane composite film. The wet coating amount of the polyurethane glue is 15 g / m 2 .

[0107] The polyurethane glue was purchased from Shanghai Bolinuo New Material Technology Co., Ltd., and the model is 5715B.

[0108] Comparative Example

[0109] Comparative Example 1

[0110] A paper protective inflatable bubble bag composite film. The difference between this comparative example and Example 1 is that steps S1-3 are omitted and the waterproof and airtight glue prepared in Preparation Example 1 is directly coated on the kraft paper.

[0111] Comparative Example 2

[0112] A paper protective inflatable bubble bag composite film. The difference between this comparative example and Example 1 is that in step S2, the lamination temperature is 130 °C and the lamination pressure is 12 MPa.

[0113] Comparative Example 3

[0114] A paper protective inflatable bubble bag composite film. The difference between this comparative example and Example 1 is that in step S2, the lamination temperature is 140 °C and the lamination pressure is 10 MPa.

[0115] Comparative Example 4

[0116] A paper protective inflatable bubble bag composite film. The difference between this example and Example 1 is that the waterproof and airtight glue comes from Comparative Preparation Example 1.

[0117] Comparative Example 5

[0118] A paper-based protective inflatable bubble bag composite film. The difference between this embodiment and Embodiment 1 is that the waterproof and air-barrier glue comes from Comparative Preparation Example 2.

[0119] Comparative Example 6

[0120] A paper-based protective inflatable bubble bag composite film. The difference between this embodiment and Embodiment 1 is that the waterproof and air-barrier glue comes from Comparative Preparation Example 3.

[0121] Comparative Example 7

[0122] A paper-based protective inflatable bubble bag composite film. The difference between this embodiment and Embodiment 1 is that the waterproof and air-barrier glue comes from Comparative Preparation Example 4.

[0123] Testing Method / Experimental Method

[0124] GTR Air Permeability Test: Test according to GB / T 1038.

[0125] Water Vapor Barrier Performance Test: Detect the water vapor transmission rate according to GB / T 1037-1988 "Test Method for Water Vapor Transmission of Plastic Films and Sheets - Cup Method".

[0126] Waterproof Performance: Immerse the paper-based protective inflatable bubble bag composite films prepared in Examples 1-8 and Comparative Examples 1-7 in water at 50 °C for 24 h, take them out, dry the water, and observe whether the kraft paper and the waterproof and air-barrier layer are separated.

[0127] Sealing Strength: Test according to the national standard GB / T 38082-2019.

[0128] Separation Test between the Waterproof and Air-Barrier Layer and the Heat-Sealing Layer: Heat-seal the paper-based protective inflatable bubble bag composite films prepared in Examples 1-8 and Comparative Examples 1-7 at 200 °C. After heat-sealing, the heat-sealing layer will deform, and in some cases, it will cause the separation of the heat-sealing layer and the waterproof and air-barrier layer. Use a magnifying glass with a magnification of 10 times to observe whether there is separation between the waterproof and air-barrier layer and the heat-sealing layer.

[0129] Tensile Strength: Detect according to GB / T 1040.3-2006 "Determination of Tensile Properties of Plastics". The better the tensile strength, the stronger and more durable the paper-based protective inflatable bubble bag composite film. The experimental data are shown in Table 4:

[0130] Table 4 Experimental Data of Examples 1-8 and Comparative Examples 1-7

[0131]

[0132]

[0133] It can be seen from Examples 1-8 and Comparative Examples 1-7 in combination with Table 4 that the paper-based protective inflatable bubble bag composite film prepared by the formula and process in this application has good waterproof and airtight properties.

[0134] Comparing Example 1 with Comparative Example 1, the air permeability and water vapor permeability in Comparative Example 1 are much greater than those in Example 1, and in the waterproof test, the kraft paper and the waterproof and airtight layer are separated, indicating that in this application, by first coating the waterproof and airtight glue on the substrate to form a waterproof and airtight layer and then laminating it with kraft paper, the waterproof and airtight properties of the paper-based protective inflatable bubble bag composite film can be greatly improved, and at the same time, it is ensured that the kraft paper and the waterproof and vapor-proof layer are not easily separated.

[0135] Comparing Example 1 with Comparative Examples 2-3, the air permeability and water vapor permeability in Comparative Examples 2-3 are much greater than those in Example 1, and in the waterproof test, the kraft paper and the waterproof and airtight layer in Comparative Example 2 are separated, indicating that by optimizing the lamination temperature and parameters, the waterproof and airtight properties of the paper-based protective inflatable bubble bag composite film can be improved, and at the same time, it is ensured that the kraft paper and the waterproof and vapor-proof layer are not easily separated.

[0136] Comparing Example 1 with Comparative Examples 4-7, the air permeability and water vapor permeability in Comparative Examples 4-7 are much greater than those in Example 1; in the waterproof test, the kraft paper and the waterproof and airtight layer in Comparative Examples 4 and 7 are separated; in the separation test of the waterproof and airtight layer and the heat-sealing layer, separation occurs in Comparative Examples 4-5, indicating that in this application, by preparing a waterproof and airtight glue with polyvinyl alcohol, polyurethane-modified silicone, water-soluble chitosan, water-soluble acrylic resin, isooctyl acrylate, cross-linking agent, ethanol and water, the waterproof and airtight properties of the paper-based protective inflatable bubble bag composite film can be effectively improved, and at the same time, the connection stability between the waterproof and airtight layer and the kraft paper and the connection stability between the waterproof and airtight layer and the heat-sealing layer can also be improved.

[0137] Comparing Example 1 with Example 6, separation occurs in Example 6 in the separation test of the waterproof and airtight layer and the heat-sealing layer, indicating that the prepared heat-sealing glue in this application has good connection stability with the waterproof and airtight layer.

[0138] Comparing Example 1 with Examples 7-8, the tensile strength of Examples 7-8 is increased by 5.6 MPa, indicating that by adding a polyurethane layer in this application, the tensile strength of the paper-based protective inflatable bubble bag composite film can be improved.

[0139] This specific embodiment is only an explanation of this application, and it is not a limitation of this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A process for preparing a composite film of a paper protective inflatable bubble bag, characterized in that: The method comprises the following preparation steps: S1, coating a waterproof and air-proof glue on the surface of the substrate, drying, forming a waterproof and air-proof layer, and obtaining a waterproof and air-proof composite film, wherein the waterproof and air-proof glue is prepared by mixing polyvinyl alcohol, polyurethane-modified silicone, water-soluble chitosan, water-soluble acrylic resin, isooctyl acrylate, a cross-linking agent, ethanol, and water; S2, pressing the kraft paper and the waterproof and air-tight composite film at a pressing temperature of 140-150° C. and a pressing pressure of 12-16 MPa, so that the kraft paper and the waterproof and air-tight layer adhere to each other to obtain a kraft paper composite film; S3, tear off the substrate layer; S4, applying heat-sealing glue on the surface of the waterproof and air-barrier layer, and drying to obtain a paper protective inflatable bubble bag composite film; The weight percentages of the raw materials used to prepare the waterproof and airtight glue are as follows: Polyvinyl alcohol 10-20% Polyurethane modified silicone 5-8% Water-soluble chitosan 3-4% Water-soluble acrylic resin 10-15% 2-Ethylhexyl acrylate 10-15% Crosslinking agent 0.5-1% Ethanol 15-25% The rest is water; The waterproof and air-isolating glue is prepared by the following method: Mix water and ethanol, add water-soluble chitosan, water-soluble acrylic resin and polyvinyl alcohol, stir until all are dissolved, add polyurethane-modified silicone, isooctyl acrylate and a cross-linking agent and stir evenly to obtain a waterproof and airtight glue; The coating weight of the waterproof and air-proof glue is 30-40g / m 2 .

2. The process for preparing a composite film of a paper protective inflatable bubble bag according to claim 1, characterized in that: The drying temperature in step S1 is 120-130° C. and the speed is 60-70 m / min.

3. The process for preparing a composite film of a paper protective inflatable bubble bag according to claim 1, characterized in that: The heat-sealing glue is prepared from the following raw materials in percentage by weight: Polyvinyl alcohol 15-20% Polyurethane modified silicone 5-8% Ethylene-vinyl acetate copolymer emulsion 5-9% Curing agent 0.5-1% Ethanol 10-20% The balance is water.

4. The process for preparing a composite film of a paper protective inflatable bubble bag according to claim 3, characterized in that: The coating weight of the heat seal glue is 5-10g / m 2 .

5. The process for preparing a composite film of a paper protective inflatable bubble bag according to claim 1, characterized in that: Before step S4, polyurethane glue is coated on the surface of the waterproof and air-barrier layer and dried to obtain a polyurethane composite film.

6. The process for preparing a composite film of a paper protective inflatable bubble bag according to claim 5, characterized in that: The coating wet weight of the polyurethane glue is 10-15g / m 2 .

7. A paper protective inflatable bubble bag composite film, characterized in that: The paper protective inflatable bubble bag composite film is prepared by the paper protective inflatable bubble bag composite film preparation process described in any one of claims 1-6.

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