Paper-plastic composite water-based hot melt adhesive for medical packaging and preparation method thereof

Abstract

This application relates to the field of water-based hot melt adhesives, specifically disclosing a paper-plastic composite water-based hot melt adhesive for medical packaging and its preparation method. The water-based hot melt adhesive comprises the following raw materials in parts by weight: 50-80 parts of water-based polyolefin dispersion, 10-40 parts of ethylene-acrylic acid copolymer emulsion, 2-10 parts of wax emulsion, 5-20 parts of filler, 0.5-2 parts of anti-settling agent, 0.1-1 parts of bactericide, and 0.1-1 parts of defoamer. The preparation method includes the following steps: mixing and stirring the water-based polyolefin dispersion, ethylene-acrylic acid copolymer emulsion, wax emulsion, filler, anti-settling agent, bactericide, and defoamer until homogeneous, and then filtering the mixture. The resulting water-based hot melt adhesive can achieve bonding and sealing between the plastic film and dialysis paper, and has good storage stability. When the PE or other plastic film and dialysis paper are torn apart, the paper will not tear, effectively preventing paper scraps and other impurities from contaminating medical supplies, thus solving the balance problem between bonding and sealing and preventing paper scraps during peeling.

Description

Technical Field

[0001] This application relates to the field of water-based hot melt adhesives, and more specifically, to a paper-plastic composite water-based hot melt adhesive for medical packaging and its preparation method. Background Technology

[0002] The paper-plastic composite sterilization packaging bags used for disposable medical supplies such as surgical gowns, cotton swabs, syringes, catheters, forceps, masks, gloves, and respirators are mainly made of materials including medical dialysis paper, coated / laminated paper, Tyvek, PE, PP, PET, and PVC. The paper base material is mainly medical dialysis paper, which is made from dehydrated wood pulp and is mainly composed of lignocellulose. Its heat-sealing properties are not good. Currently used heat-sealing adhesives are mostly made of thermoplastic polyurethane resin as the main raw material, supplemented with tackifiers, antioxidants, and other additives. They need to be heated and melted during use, and the pressing temperature must be above 150°C and the pressing time must be greater than 0.5 seconds. Moreover, the contents are easily adhered after the adhesive is applied. When the PE or other plastic film and dialysis paper are torn apart, the paper is easily torn, which greatly increases the possibility of paper scraps and other impurities contaminating the contents of the packaging and compromising the cleanliness of the medical supplies. Summary of the Invention

[0003] This application provides a water-based hot melt adhesive for paper-plastic composite packaging in medical packaging and its preparation method. The water-based hot melt adhesive has high thermal sensitivity when used for paper-plastic composite packaging bags for sterilization. It can achieve bonding and sealing between the plastic film and dialysis paper under low pressing temperature (100-110℃) and short pressing time (0.2-0.4s). The water-based hot melt adhesive has good storage stability and good anti-aging properties after application, preventing bacteria and other microorganisms from contaminating the contents. When the PE plastic film and dialysis paper are torn apart, the paper will not be torn, effectively avoiding contamination of the packaging contents by paper scraps and other impurities, and ensuring the cleanliness of medical supplies.

[0004] In the first aspect, the paper-plastic composite water-based hot melt adhesive for medical packaging provided in this application adopts the following technical solution: A paper-plastic composite water-based hot melt adhesive for medical packaging includes the following raw materials in parts by weight: 50-80 parts of water-based polyolefin dispersion, 10-40 parts of ethylene-acrylic acid copolymer emulsion, 2-10 parts of wax emulsion, 5-20 parts of filler, 0.5-2 parts of anti-settling agent, 0.1-1 parts of bactericide, and 0.1-1 parts of defoamer; The solid content of the aqueous polyolefin dispersion ranges from 20% to 40%, and its dry film melting point ranges from 80 to 95°C; the solid content of the ethylene-acrylic acid copolymer emulsion ranges from 25% to 50%, and its dry film melting point ranges from 75 to 110°C.

[0005] This application uses an aqueous polyolefin dispersion, which has polar groups and is similar to and compatible with PP / PE, both being polyolefins, exhibiting excellent adhesion. The molecular structure of the ethylene-acrylic acid copolymer emulsion has carboxyl groups randomly distributed on the ethylene main chain and branches, resulting in excellent adhesion and toughness. It easily combines with polar substances and has excellent adhesion to materials such as metal foil, paper, nylon, polyolefins, and glass. By compounding the aqueous polyolefin dispersion and the ethylene-acrylic acid copolymer emulsion, the balance between bonding and sealing and paper breakage during packaging bag peeling is solved, which helps to reduce paper breakage during peeling.

[0006] Furthermore, by compounding waterborne polyolefin aqueous dispersions and ethylene-acrylic acid copolymer emulsions, and strictly controlling the solid content and dry film melting point of each component, the waterborne hot melt adhesive not only exhibits fast heat-sealing response and high thermal sensitivity, allowing for smaller application amounts, lower heat-sealing temperatures, and shorter pressing times, but also melts upon heating at lower temperatures, demonstrating excellent heat-sealing performance. Moreover, the resulting waterborne hot melt adhesive possesses excellent mechanical stability, adaptable to roller coating, spraying, scraping, and brushing processes. It can be evenly distributed on the substrate surface using appropriate application tools, and can be pre-coated onto paper before drying and winding, significantly reducing application difficulty. Experimental studies have shown that bonding and sealing between the plastic film and dialysis paper can be achieved under pressing temperatures of 100-110℃ and pressing times of 0.2-0.4s, resulting in cost reduction, energy saving, and increased production efficiency, leading to excellent economic benefits.

[0007] The components, including waterborne polyolefin aqueous dispersion, ethylene-acrylic acid copolymer emulsion, wax emulsion, fillers, and anti-settling agents, work together to form an interpenetrating network, which gives the waterborne hot melt adhesive good storage stability and good anti-aging properties after application. This prevents the packaging bag from opening during storage and effectively prevents bacteria and other microorganisms from contaminating the contents, ensuring the cleanliness of medical supplies.

[0008] During the film-forming process of aqueous polyolefin dispersions and ethylene-acrylic acid copolymer emulsions, the wax emulsion migrates to the surface of the polymer film. Working in conjunction with anti-settling agents, it ensures uniform dispersion, forming a wax protective layer interspersed within the macromolecular polymer chains. This reduces the coefficient of friction and creates a release effect, preventing paper tearing and paper scraps during peeling, resulting in smoother peeling and effectively preventing contamination of the contents by paper scraps and other impurities. It also helps improve the tackiness of pre-coated paper, ensuring that the contents of the packaging bag do not adhere after adhesive application, and assists other raw materials in improving the heat resistance of the finished product.

[0009] Preferably, the wax emulsion is one or more of PE wax emulsion, paraffin emulsion, or aqueous wax dispersion.

[0010] Furthermore, as a preferred option for wax emulsions, PE wax emulsions are selected.

[0011] Experimental research has shown that using PE wax emulsion can further improve the flexibility of the adhesive film after water-based hot melt adhesive is applied, making the peeling of plastic film and dialysis paper smoother and effectively preventing paper scraps and other impurities from contaminating the contents.

[0012] Preferably, the filler comprises one or more of calcium carbonate, titanium dioxide, starch, kaolin, or talc.

[0013] Titanium dioxide has excellent hiding power and weather resistance, which can improve the whiteness and hiding power of the film. Starch has good adhesion and can improve the bonding strength of the colloid. Talc has excellent slipperiness and wear resistance, which can improve the wear resistance and flowability of the colloid. Calcium carbonate can act as a filler and thickener, which can improve the strength and hardness of the film and improve its heat resistance. Kaolin can effectively improve the flowability and coating performance of the colloid and improve its stability.

[0014] Preferably, the filler comprises calcium carbonate and kaolin in a mass ratio of 1:(2-4).

[0015] Experimental studies have shown that when calcium carbonate and kaolin are used as fillers within the above-mentioned dosage range, the calcium carbonate and kaolin in the resulting water-based hot melt adhesive can be distributed in the polymer film after film formation, reducing the density of the dry film and improving its air permeability.

[0016] Preferably, the anti-settling agent comprises one or more of fumed silica, bentonite, silicate, or montmorillonite.

[0017] Fumed silica possesses high dispersibility and excellent chemical stability, which can enhance the thixotropy of colloids. This means the colloid's fluidity increases under shear force and decreases when the shear force ceases, making it easy to flow during coating while maintaining a certain level of stability after coating. Bentonite has good adsorption and thickening properties, increasing the viscosity and thixotropy of colloids, and improving their tensile strength and crack resistance. Silicates can act as reinforcing agents, improving the strength and hardness of colloids. Montmorillonite, with its unique layered structure and good adsorption properties, can act as a thickener and stabilizer, improving the viscosity and stability of colloids.

[0018] Preferably, the anti-settling agent comprises fumed silica and montmorillonite in a mass ratio of 1:(2-4).

[0019] Experimental studies have shown that using fumed silica and montmorillonite as anti-settling agents within the above-mentioned dosage range results in water-based hot melt adhesives with better storage stability.

[0020] Preferably, the bactericide is one or more of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, and 1,2-benzisothiazolin-3-one.

[0021] Preferably, the defoamer is one or more of the following: acetylenic diol defoamer, mineral oil defoamer, organosilicon defoamer, and vegetable oil defoamer.

[0022] Optimize the selection of bactericides and defoamers to help improve the overall performance of water-based hot melt adhesives.

[0023] Secondly, this application provides a method for preparing a paper-plastic composite water-based hot melt adhesive for medical packaging, using the following technical solution: A method for preparing a paper-plastic composite waterborne hot melt adhesive for medical packaging includes the following steps: mixing and stirring a waterborne polyolefin dispersion, an ethylene-acrylic acid copolymer emulsion, a wax emulsion, a filler, an anti-settling agent, a bactericide, and an antifoaming agent until homogeneous, and then filtering and discharging the material.

[0024] Preferably, the stirring speed is increased and the dispersion is uniform after adding the ethylene-acrylic acid copolymer emulsion to the stirred aqueous polyolefin dispersion; While stirring, add the wax emulsion and stir until well combined; Add the filler and increase the stirring speed until the filler is completely and evenly dispersed; Add the anti-settling agent and mix well. Reduce the stirring speed and add the bactericide and defoamer and mix well. Filter the mixture through a 100-200 mesh screen.

[0025] Mixing the raw material components in stages helps to better disperse them in the system, resulting in a water-based hot melt adhesive with good flowability and better coating performance.

[0026] In summary, this application has the following beneficial effects: 1. This application uses an aqueous polyolefin dispersion, which has polar groups and is similar to and compatible with PP / PE, both being polyolefins, exhibiting excellent adhesion. The molecular structure of the ethylene-acrylic acid copolymer emulsion has carboxyl groups randomly distributed on the ethylene main chain and branches, resulting in excellent adhesion and toughness. It easily combines with polar substances and has excellent adhesion to materials such as metal foil, paper, nylon, polyolefins, and glass. By compounding the aqueous polyolefin dispersion and the ethylene-acrylic acid copolymer emulsion, the balance between bonding and sealing and paper breakage during peeling of packaging bags is solved, which helps to reduce paper breakage during peeling.

[0027] 2. After compounding waterborne polyolefin aqueous dispersion and ethylene-acrylic acid copolymer emulsion, and strictly controlling the solid content and dry film melting point of each component, the waterborne hot melt adhesive not only has a fast heat-sealing response and high thermal sensitivity, but also adapts to less adhesive application, lower heat-sealing temperature, and shorter pressing time. It melts at a lower temperature during use, exhibiting excellent heat-sealing performance. Furthermore, the resulting waterborne hot melt adhesive has good mechanical stability and is suitable for roller coating, spraying, scraping, and brushing processes. It can be evenly distributed on the substrate surface using appropriate application tools. It can be pre-coated onto paper, dried, and then rolled up, greatly reducing the difficulty of use. Experimental studies have shown that bonding and sealing between the plastic film and dialysis paper can be achieved under the conditions of a pressing temperature of 100-110℃ and a pressing time of 0.2-0.4s, resulting in advantages such as reduced costs, energy saving, and improved production efficiency, bringing excellent economic benefits.

[0028] 3. The components, such as waterborne polyolefin aqueous dispersion, ethylene-acrylic acid copolymer emulsion, wax emulsion, filler and anti-settling agent, work together to form an interpenetrating network, which gives the waterborne hot melt adhesive good storage stability and good anti-aging properties after application. This ensures that the packaging bag does not open during storage, effectively preventing bacteria and other microorganisms from contaminating the contents and ensuring the cleanliness of medical supplies.

[0029] 4. During the film-forming process of aqueous polyolefin dispersions and ethylene-acrylic acid copolymer emulsions, the wax emulsion migrates to the surface of the polymer film, adjusting the colloidal adhesion strength. In conjunction with anti-settling agents, it ensures uniform dispersion, forming a wax protective layer interspersed within the macromolecular polymer chains. This reduces the coefficient of friction, creating a release effect and preventing paper tearing and paper scraps from falling off during peeling, resulting in smoother peeling and effectively preventing contamination of the contents by paper scraps and other impurities. It also helps improve the tackiness of pre-coated paper, ensuring that the contents of the packaging bag do not adhere after adhesive application, and assists other raw materials in improving the heat resistance of the finished product. Attached Figure Description

[0030] Figure 1 This is a product image of Embodiment 9 of this application after being stored for 6 months.

[0031] Figure 2 This is a photograph of the actual product after a paper tearing and peeling test was performed on Example 9 of this application.

[0032] Figure 3 This is a photograph of the actual product after a paper tearing and peeling test was conducted on Comparative Example 2 of this application.

[0033] Figure 4 This is a photograph of the actual product after a paper tearing and peeling test was conducted on Comparative Example 3 of this application. Detailed Implementation

[0034] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0035] The PE wax emulsion is of the following type: CT 1849; the model number of the acetylenic diol defoamer is... WE3650; Paraffin emulsion model: LW-103; Water-based wax dispersion model: Twax-2101; Mineral oil defoamer model: Mo 2111; the silicone defoamer is model Defoamer 1903; the vegetable oil defoamer is model Defoamer 1810.

[0036] When heat-sealing paper and plastic composites, it was found that the paper base material of medical supplies is mainly medical dialysis paper, which cannot be heat-sealed with most plastic-based polymer materials. Experiments revealed that using solid hot melt adhesives has drawbacks such as large adhesive application volume, slow coating speed, high cost, poor air permeability, and easy adhesion of contents after application. Water-based adhesives, on the other hand, can be applied using anilox rollers, requiring less adhesive and achieving faster coating speeds, thus reducing costs and saving energy while improving production efficiency. However, current water-based adhesives have not been satisfactory in terms of the stability and reliability of heat-sealing strength; most water-based adhesive products have low heat-sealing strength, failing to meet industry standards. Furthermore, finished bags made with high-heat-sealing-strength water-based adhesives often shed paper scraps when torn, affecting the cleanliness of the medical supplies inside and seriously impacting the quality of sterilization packaging bags. This has always been a pain point and challenge for the industry. In addition to meeting the above bonding requirements, water-based hot melt adhesives must also take into account their stability during storage, ensuring that they do not separate or clump during long-term storage, thus guaranteeing their workability.

[0037] Therefore, based on this, there is an urgent need to develop a water-based hot melt adhesive with high thermal sensitivity. This adhesive can achieve the sealing and bonding of plastic film and medical dialysis paper with relatively low external heat sealing pressure and temperature, and has good storage stability. At the same time, when the PE plastic film and dialysis paper are torn apart, the paper will not be torn, thus solving the balance problem between bonding and sealing and tearing of paper when the packaging bag is peeled off. This will prevent paper scraps and other impurities from contaminating medical supplies and ensure the cleanliness of the contents in the packaging bag. Example

[0038] Example 1 A paper-plastic composite water-based hot melt adhesive for medical packaging comprises the following raw materials: 5 kg of water-based polyolefin dispersion, 4 kg of ethylene-acrylic acid copolymer emulsion, 0.2 kg of wax emulsion, 0.5 kg of filler, 0.05 kg of anti-settling agent, 0.01 kg of bactericide, and 0.01 kg of defoamer; the solid content of the water-based polyolefin dispersion is 40%, and its dry film melting point range is 80-85℃; the solid content of the ethylene-acrylic acid copolymer emulsion is 25%, and its dry film melting point range is 75-80℃. The wax emulsion is a paraffin emulsion, the filler is titanium dioxide and starch in a mass ratio of 1:1, the anti-settling agent is bentonite, the bactericide is 5-chloro-2-methyl-4-isothiazolin-3-one, and the defoamer is acetylenic diol defoamer.

[0039] A method for preparing paper-plastic composite water-based hot melt adhesive for medical packaging includes: Step 1: Add the aqueous polyolefin dispersion to the mixing tank, adjust the stirring speed to 200 rpm, and stir for 10 minutes; Step 2: While stirring, add the ethylene-acrylic acid copolymer emulsion, adjust the stirring speed to 250 rpm, and stir for 20 minutes; Step 3: While stirring, add the wax emulsion at a stirring speed of 250 rpm for 20 minutes; Step 4: While stirring, slowly add the filler into the mixing vessel. After all the filler has been added, increase the stirring speed to 350 rpm and stir continuously for 50 minutes until the filler is completely and evenly dispersed. Step 5: While stirring, add the anti-settling agent, maintaining a stirring speed of 350 rpm, and stir for 20 minutes; Step 6: While stirring, add the bactericide and defoamer, adjust the stirring speed to 300 rpm, and stir for 20 minutes; Step 7: After all the raw materials are completely mixed, filter the mixture through a 150-mesh filter.

[0040] Example 2 A paper-plastic composite water-based hot melt adhesive for medical packaging comprises the following raw materials: 8 kg of water-based polyolefin dispersion, 1 kg of ethylene-acrylic acid copolymer emulsion, 1 kg of wax emulsion, 2 kg of filler, 0.2 kg of anti-settling agent, 0.1 kg of bactericide, and 0.1 kg of defoamer; The solid content of the waterborne polyolefin dispersion is 20%, and its dry film melting point ranges from 90 to 95°C; the solid content of the ethylene-acrylic acid copolymer emulsion is 50%, and its dry film melting point ranges from 100 to 110°C. The wax emulsion is an aqueous wax dispersion, the filler is titanium dioxide, starch and kaolin in a mass ratio of 1:1:2, the anti-settling agent is fumed silica and montmorillonite in a 1:2 ratio, the bactericide is 2-methyl-4-isothiazolin-3-one, and the defoamer is a mineral oil defoamer.

[0041] Example 3 The difference from Example 2 is that a paper-plastic composite water-based hot melt adhesive for medical packaging includes the following raw materials: 6 kg of water-based polyolefin dispersion, 3 kg of ethylene-acrylic acid copolymer emulsion, 0.7 kg of wax emulsion, 1.2 kg of filler, 0.1 kg of anti-settling agent, 0.05 kg of bactericide, and 0.06 kg of defoamer; The solid content of the aqueous polyolefin dispersion is 30%, and its dry film melting point ranges from 85 to 90°C; the solid content of the ethylene-acrylic acid copolymer emulsion is 35%, and its dry film melting point ranges from 90 to 95°C; the rest are the same as in Example 2.

[0042] Example 4 The difference from Example 3 is that the wax emulsion is a PE wax emulsion, while the rest are the same as in Example 3.

[0043] Example 5 The difference from Example 4 is that the filler is calcium carbonate, starch and talc in a ratio of 1:4:0.7, while the rest is the same as in Example 4.

[0044] Example 6 The difference from Example 4 is that the filler is calcium carbonate and kaolin in a 1:3 ratio, while the rest are the same as in Example 4.

[0045] Example 7 The difference from Example 6 is that the anti-settling agent is fumed silica and bentonite in a ratio of 2:0.7, while the rest is the same as Example 6.

[0046] Example 8 The difference from Example 7 is that the anti-settling agent is fumed silica and montmorillonite in a 1:3.5 ratio, while the rest is the same as in Example 6.

[0047] Example 9 The difference from Example 8 is that the bactericide is 1,2-benzisothiazolin-3-one, and the defoamer is an organosilicone defoamer; all other aspects are the same as in Example 8.

[0048] Comparative Example Comparative Example 1 The difference from Example 9 is that the aqueous polyolefin dispersion is replaced with a polyurethane emulsion, while the rest are the same as in Example 9.

[0049] Comparative Example 2 The difference from Example 9 is that the ethylene-acrylic acid copolymer emulsion is replaced with a polyethylene-vinyl acetate emulsion, while the rest are the same as in Example 9.

[0050] Comparative Example 3 The difference from Example 9 is that no wax emulsion is added; otherwise, they are the same as in Example 9.

[0051] Performance testing The water-based hot melt adhesives prepared in Examples 1-9 and Comparative Examples 1-3 were pre-coated onto dialysis paper using a roller coating method to achieve a sealed bond with the plastic film. Each set of packaging bags contained 10 bags. The specific steps were as follows: 1. Apply water-based hot melt adhesive to the dialysis paper using a 15-mesh wire rod; 2. Dry in an oven at 55℃; 3. Remove the dialysis paper from the oven and allow it to cool to room temperature; 4. Perform hot-press lamination of plastic film and paper on a heat sealer with a set pressing pressure of 0.5MPa, pressing temperature of 105℃, and pressing time of 0.3s.

[0052] The peel strength was determined according to YY / T 0698.5-2009 "Packaging materials for terminally sterilized medical supplies - Part 5: Requirements and test methods for sealable combination bags and rolls composed of breathable materials and plastic films", and the average value of each group was recorded in Table 1.

[0053] Storage stability tests were conducted on the water-based hot melt adhesives prepared in Examples 1-9 and Comparative Examples 1-3: the adhesives were stored in a constant temperature room at 23°C and 50% humidity for 6 months, and the changes in product appearance and viscosity were observed to determine whether stratification or sedimentation occurred. The results are recorded in Table 1.

[0054] Medical product paper-plastic packaging bags coated with the water-based hot melt adhesives prepared in Examples 1-9 and Comparative Examples 1-3 were subjected to paper tearing tests, and the tearing conditions were recorded. The results are shown in Table 1.

[0055] Table 1 When the water-based hot melt adhesives prepared in Examples 1-9 were heat-sealed using a heat sealer, it was observed that the prepared water-based hot melt adhesives exhibited high thermal sensitivity when used for paper-plastic composite sterilization packaging bags. Under conditions of low pressing temperature (100-110℃) and short pressing time (0.2-0.4s), bonding and sealing between the plastic film and dialysis paper could be achieved. This, combined with Table 1 and... Figure 1 As can be seen, the prepared water-based hot melt adhesive has good storage stability and good anti-aging properties after application, preventing bacterial and other microbial contamination of the contents. Further, through Example 9 and... Figure 2 As can be seen, when the PE plastic film and dialysis paper are torn apart, the paper will not break, effectively preventing paper scraps and other impurities from contaminating the contents and ensuring the cleanliness of medical supplies.

[0056] As can be seen from Examples 9 and Comparative Examples 1-3, and in conjunction with Table 1, in Comparative Example 1, where the aqueous polyolefin dispersion was replaced with a polyurethane emulsion, the product could not be effectively activated under the set low pressing temperature and short pressing time conditions. The peel strength was too low, failing to achieve effective sealing of the medical packaging bag. Simultaneously, the storage stability of the aqueous hot melt adhesive was poor, exhibiting stratification and sedimentation. In Comparative Example 2, where the ethylene-acrylic acid copolymer emulsion was replaced with a polyethylene-vinyl acetate emulsion, the resulting aqueous hot melt adhesive had a moderate peel strength, but due to its strong penetration into paper, it still experienced jamming during the peeling process, resulting in a significant amount of paper scraps falling off (e.g., ...). Figure 3 As shown), the product's storage stability was also poor, with a significant increase in viscosity. Comparative Example 3 lacked wax emulsion, resulting in excessively high peel strength and jamming during peeling, causing some paper scraps to fall off (e.g.). Figure 4 (As shown). This is because the combination of aqueous polyolefin dispersion and ethylene-acrylic acid copolymer emulsion solves the balance problem between bonding and sealing and paper tearing during peeling, and helps reduce paper tearing during peeling. Furthermore, the addition of a wax emulsion to adjust the colloidal bonding strength allows the wax to migrate to the surface of the polymer film during the film-forming process of the aqueous polyolefin dispersion and ethylene-acrylic acid copolymer emulsion, forming a wax protective layer interspersed within the macromolecular polymer chains. This reduces the coefficient of friction and creates a certain release effect, thereby preventing paper tearing and paper scraps from falling off during peeling, resulting in smoother peeling and effectively preventing paper scraps and other impurities from contaminating the contents.

[0057] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A paper-plastic composite water-based hot melt adhesive for medical packaging, characterized in that, The raw materials include the following parts by weight: 50-80 parts of aqueous polyolefin dispersion, 10-40 parts of ethylene-acrylic acid copolymer emulsion, 2-10 parts of wax emulsion, 5-20 parts of filler, 0.5-2 parts of anti-settling agent, 0.1-1 parts of bactericide, and 0.1-1 parts of defoamer; the solid content of the aqueous polyolefin dispersion ranges from 20-40%, and its dry film melting point ranges from 80-95℃; the solid content of the ethylene-acrylic acid copolymer emulsion ranges from 25-50%, and its dry film melting point ranges from 75-110℃; the filler includes calcium carbonate and kaolin in a mass ratio of 1:(2-4); the anti-settling agent includes fumed silica and montmorillonite in a mass ratio of 1:(2-4); The water-based hot melt adhesive is used for laminating plastic film and dialysis paper in medical sterilization packaging bags.

2. The paper-plastic composite water-based hot melt adhesive for medical packaging according to claim 1, characterized in that: The bactericide is one or more of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, and 1,2-benzisothiazolin-3-one.

3. The paper-plastic composite water-based hot melt adhesive for medical packaging according to claim 1, characterized in that: The defoamer is one or more of the following: acetylenic diol defoamer, mineral oil defoamer, organosilicon defoamer, and vegetable oil defoamer.

4. The preparation method of the paper-plastic composite water-based hot melt adhesive for medical packaging according to any one of claims 1-3, characterized in that: Includes the following steps: The aqueous polyolefin dispersion, ethylene-acrylic acid copolymer emulsion, wax emulsion, filler, anti-settling agent, bactericide and defoamer are mixed and stirred evenly, and then filtered out.

5. The preparation method of the paper-plastic composite water-based hot melt adhesive for medical packaging according to claim 4, characterized in that: Stir the aqueous polyolefin dispersion, add the ethylene-acrylic acid copolymer emulsion, increase the stirring speed and disperse evenly; while stirring, add the wax emulsion and stir evenly; then add the filler and increase the stirring speed until the filler is completely and evenly dispersed; add the anti-settling agent and mix evenly, reduce the stirring speed and add the bactericide and defoamer and mix evenly, then filter the material through a 100-200 mesh filter.

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