Environment-friendly stainless steel sheet lining paper and preparation method thereof

Abstract

The invention is suitable for the technical field of packaging materials, and provides green and environment-friendly stainless steel sheet lining paper and a preparation method thereof.The lining paper is of a three-layer composite structure: a surface anti-rust layer contains citric acid and plant fibers and is loaded with bio-based phytic acid and chemical crosslinking type starch-based glycan, and lasting rust prevention is achieved; the middle buffer layer comprises PLA microfibers, cork paper pulp and modified chitosan, and provides high softness and rebound resilience; the bottom supporting layer comprises plant fibers and modified nano silicon dioxide and provides high-strength support. Through the chemical crosslinking type starch-based glycan, chitosan quaternization-grafting, nano silicon dioxide polydopamine-silanization and three-layer composite structure design, on the premise that a volatile corrosion inhibitor is completely abandoned, excellent anti-rust property, high flexibility, high strength and buffering performance are achieved at the same time, hair falling and powder falling are avoided, and the service life of the coating is prolonged. The traditional lining paper is comprehensively surpassed.

Description

Technical Field

[0001] This invention belongs to the field of packaging materials technology, and in particular relates to a green and environmentally friendly stainless steel sheet liner and its preparation method. Background Technology

[0002] Stainless steel sheets are widely used due to their excellent surface finish and corrosion resistance. During stacking, transportation, and storage, liner paper is used for isolation to prevent scratches between sheets, fingerprint contamination, and environmental corrosion.

[0003] Traditional stainless steel lining paper mostly uses formulations containing volatile corrosion inhibitors (VCIs, such as nitrites and amine compounds). These chemicals may volatilize during production and use, posing potential hazards to operator health and the natural environment. Paper itself is prone to shedding and dusting due to its weak fiber bonding. Fine fibers and particles can contaminate the delicate stainless steel surface, affecting subsequent processing or use.

[0004] Meanwhile, the lining paper needs to have high softness, high strength and certain cushioning properties to effectively protect the stainless steel plate. Summary of the Invention

[0005] This invention provides a green and environmentally friendly stainless steel sheet liner paper and its preparation method, aiming to solve the above-mentioned problems.

[0006] The present invention is achieved as follows: a green and environmentally friendly stainless steel sheet backing paper, which has a three-layer composite structure, including a surface anti-rust layer, an intermediate buffer layer and a bottom support layer. The surface anti-rust layer comprises plant fibers cross-linked with citric acid and loaded with phytic acid, as well as chemically cross-linked starch-based polysaccharides. The citric acid cross-linking not only physically strengthens the fiber network and reduces shedding, but also forms hydrogen bonds between its carboxyl groups and the phosphate groups of phytic acid, stabilizing phytic acid and controlling its release, thus extending the anti-rust time and avoiding the volatilization problem of traditional VCI, achieving environmentally friendly anti-rust. The chemically cross-linked starch-based polysaccharide molecular chain contains both carboxyl and amide groups, which can covalently cross-link with the citric acid and cellulose of the surface anti-rust layer, enhancing the density of the anti-rust layer and anchoring phytic acid, thereby strengthening the bonding force between fibers and making the anti-rust effect more durable.

[0007] The intermediate buffer layer comprises polylactic acid (PLA) microfibers, cork pulp, and modified chitosan. The PLA microfibers are biodegradable and highly flexible; when mixed with cork pulp, they form a highly porosity buffer layer, providing excellent cushioning performance and resilience, effectively absorbing impact forces. Modified chitosan improves the compatibility of PLA with the pulp and enhances the interlayer bonding.

[0008] The bottom support layer comprises plant fibers and modified nano-silica dispersed therein; the plant fibers provide mechanical support to prevent the liner paper from tearing during use, and the introduction of modified nano-silica significantly enhances the inter-fiber bonding force and the overall mechanical strength of the paper.

[0009] Preferably, the surface anti-rust layer comprises, by weight: 100 parts plant fiber, 3-8 parts phytic acid, 5-10 parts citric acid, and 0.5-2 parts chemically cross-linked starch-based polysaccharide; the intermediate buffer layer comprises, by weight: 50-70 parts PLA microfiber, 30-50 parts cork pulp, and 1-3 parts modified chitosan; and the bottom support layer comprises, by weight: 100 parts plant fiber and 1-3 parts modified nano-silica.

[0010] Preferably, the surface anti-rust layer comprises, by weight: 100 parts plant fiber, 4-7 parts phytic acid, 6-9 parts citric acid, and 1-1.5 parts chemically cross-linked starch-based polysaccharide; the intermediate buffer layer comprises, by weight: 55-65 parts PLA microfiber, 35-45 parts cork pulp, and 1.5-2.5 parts modified chitosan; and the bottom support layer comprises, by weight: 100 parts plant fiber and 1.5-2.5 parts modified nano-silica.

[0011] Preferably, the surface anti-rust layer comprises, by weight: 100 parts plant fiber, 5.5 parts phytic acid, 7.5 parts citric acid, and 1.25 parts chemically cross-linked starch-based polysaccharide; the intermediate buffer layer comprises, by weight: 60 parts PLA microfiber, 40 parts cork pulp, and 2 parts modified chitosan; and the bottom support layer comprises, by weight: 100 parts plant fiber and 2 parts modified nano-silica.

[0012] Preferably, the chemically cross-linked starch-based polysaccharide is a carboxymethyl starch-polyacrylamide graft copolymer (CMS-g-PAM), and its preparation method is as follows: Starch was dispersed in an alcohol-water mixed solvent (the volume ratio of alcohol to water was 1-3:1, and the alcohol was isopropanol or ethanol), and etherified with chloroacetic acid under alkaline conditions to prepare carboxymethyl starch (CMS). The degree of substitution (determined by acid-base titration) was controlled to be 0.2-0.4. Carboxymethyl starch and acrylamide monomer were dissolved in water at a mass ratio of 1:(0.5-1); Under the action of a redox initiation system, a graft copolymerization reaction was carried out at 50-70℃, the pH value of the reaction system was controlled at 7-9, and the reaction time was 2-4 hours to obtain a carboxymethyl starch-polyacrylamide graft copolymer (CMS-g-PAM).

[0013] The CMS-g-PAM molecular chain contains both carboxyl and amide groups, which can covalently cross-link with the citric acid and cellulose in the surface anti-rust layer to form a three-dimensional covalent cross-linked network that runs through the entire anti-rust layer. This enhances the bonding force between fibers and the density of the anti-rust layer. The three-dimensional network can anchor phytic acid molecules in the fiber network through hydrogen bonding and coordination, making the anti-rust effect more durable. Its carboxyl groups can also generate strong electrostatic interactions and hydrogen bonds with the modified chitosan in the intermediate buffer layer and the modified nano-silica in the bottom support layer, thus acting as "molecular bridges" to significantly improve the interlayer bonding force.

[0014] Preferably, the alkaline conditions are provided by sodium hydroxide, and the molar ratio of sodium hydroxide to starch is (2.0-3.0):1; the molar ratio of chloroacetic acid to starch is (0.8-1.2):1; the etherification reaction temperature is 55-65℃, and the reaction time is 3-5 hours.

[0015] Preferably, the redox initiation system is a potassium persulfate-sodium bisulfite system, wherein the amount of potassium persulfate added is 1.0%-2.5% of the dry starch mass, and the molar ratio of sodium bisulfite to potassium persulfate is (0.8-1.2):1.

[0016] Preferably, the modified chitosan is a product obtained through quaternization-grafting composite modification, and its preparation method is as follows: Chitosan was quaternized by reacting it with 2,3-epoxypropyltrimethylammonium chloride at a mass ratio of 1:(0.8-1.2) at 55-65℃ for 3.5-4.5 hours. Subsequently, a graft copolymerization reaction was carried out with polyethylene glycol (PEG) methyl ether methacrylate at 30%-50% of the chitosan mass. The graft copolymerization reaction required the addition of potassium persulfate as an initiator, with the addition amount being 0.5%-1% of the initial dry weight of chitosan. The modified chitosan was obtained by reacting at 65-75℃ for 2.5-3.5 hours.

[0017] The PEG side chain significantly improves the compatibility between chitosan and PLA microfibers, and the grafted chains entwine PLA molecules to form physical cross-linking points; the quaternary ammonium groups provide positive charges and electrostatic interactions with the fibers, while the PEG segments provide flexibility and lubrication, allowing the buffer layer to distribute stress more evenly under pressure; the quaternary ammonium structure disrupts the microbial cell membrane, preventing the liner paper from becoming moldy in humid environments; and the interfacial bonding strength between modified chitosan and PLA microfibers is enhanced.

[0018] Preferably, the modified nano-silica is a product obtained by polydopamine coating-silane coupling modification, and its preparation method is as follows: Nano-silica was dispersed in a dopamine-Tris buffer solution with a pH of 8.3-8.7, and the mass ratio of nano-silica to dopamine was 1:(0.25-0.35). Polydopamine coating was achieved by shaking polymerization at room temperature for 11-13 hours. The coated product was then dispersed in an ethanol medium and reacted with mercaptopropyltriethoxysilane at 20%-30% of the mass of nano-silica at 55-65°C for 1.5-2.5 hours to silanize the modified nano-silica (particle size 10-50 nm).

[0019] Polydopamine provides a large number of catechol groups, which form strong hydrogen bonds and π-π stacking with cellulose fibers; mercaptosilane further crosslinks with the fibers, and the modified nano-silica is more evenly dispersed in the fiber network, effectively transferring and dispersing stress and improving tensile strength; mercapto can capture free radicals, delay material aging, and extend the service life of the liner paper.

[0020] The quaternary ammonium positive charge of modified chitosan attracts the polydopamine negative charge layer of modified nano-silica, forming an electrostatic-hydrogen bond complex network at the buffer-support layer interface, thus improving the interlayer bonding strength. The thiol groups of modified nano-silica and the residual amino groups of modified chitosan can form dynamic covalent bonds, reconstructing energy under stress and improving the toughness of the lining paper. The antibacterial properties of quaternary ammonium chitosan combined with the antioxidant properties of thiol-based silica provide comprehensive protection against both biological and non-biological degradation of the lining paper.

[0021] Preferably, the plant fiber of the surface anti-rust layer is bamboo pulp fiber or wood pulp fiber, with a fiber length of 1-3 mm; the PLA microfiber of the intermediate buffer layer has a diameter of 1-10 μm and a length of 3-10 mm; and the plant fiber of the bottom support layer is bamboo pulp fiber or hemp pulp fiber, with a fiber length of 2-4 mm.

[0022] The present invention also provides a method for preparing the above-mentioned green and environmentally friendly stainless steel sheet liner paper, comprising the following steps: 1. Preparation of each layer of slurry: Surface anti-rust slurry: Disperse plant fiber slurry in water (to form a slurry with a concentration of 3%-5%), add phytic acid (concentration of 10%-20%) and stir (30-50 min) for adsorption, then add citric acid (5%-10% of fiber mass) and catalyst (such as sodium hypophosphite, accounting for 1% of citric acid mass), adjust the pH to 3-4, and react at 80-90℃ for 1-2 hours to complete cross-linking, and finally add chemically cross-linked starch-based polysaccharide and stir (30-40 min) until uniform.

[0023] Intermediate buffer layer slurry: PLA microfibers and cork pulp are mixed and dispersed in water (to form a slurry with a concentration of 2%-4%), and modified chitosan solution (concentration of 1%-2%) is added and stirred (50-60 min) until uniform.

[0024] Bottom support layer slurry: Disperse plant fiber slurry in water (to form a slurry with a concentration of 4%-6%), add modified nano silica suspension (concentration of 5%-10%), and stir (50-60 min) until uniform.

[0025] 2. Multi-layer papermaking: Using a multi-layer inclined wire paper machine or a rotary wire paper machine, the bottom support layer pulp, the middle buffer layer pulp and the surface anti-rust layer pulp are sequentially fed onto the wire for dewatering and forming to obtain a wet paper sheet.

[0026] 3. Pressing and dewatering: Mechanically press the wet paper sheet at a pressure of 0.5-1.0 MPa for 1-2 minutes.

[0027] 4. Drying and Hot Pressing: Drying is carried out using a drying cylinder or hot air at a temperature of 80-110℃. Then, hot pressing is performed at a temperature of 120-150℃, a pressure of 1-2 MPa, and a time of 1-2 minutes to partially melt and bond the PLA microfibers in the intermediate buffer layer, enhancing the interlayer bonding.

[0028] 5. Surface calendering and winding: The surface is treated by a soft calender with a calendering pressure of 0.1-0.5MPa and a temperature of 60-80℃. Finally, the finished liner paper is wound up.

[0029] Compared with the prior art, the embodiments of this application have the following main advantages: It uses bio-based phytic acid and biodegradable PLA, chitosan and other materials, which are harmless to the environment and users.

[0030] By cross-linking the fibers with citric acid and loading them with phytic acid, a strong protective surface with sustained-release rust prevention function is formed. Chemically cross-linked starch-based polysaccharides further enhance the density of the rust-preventive layer and anchor the phytic acid, thereby strengthening the bonding force between fibers and making the rust prevention effect more durable.

[0031] The porous structure of the intermediate buffer layer and the flexibility of PLA microfibers give the liner paper extremely low bending stiffness. The unique buffer layer design, combined with the toughening effect of modified chitosan, gives the liner paper a high compression resilience.

[0032] The bottom support layer provides high tensile strength and tear resistance through the reinforcing effect of modified nano-silica and the selection of long fibers.

[0033] The fibers are tightly bound together through chemical cross-linking, nanoparticle filling, and intermolecular forces, resulting in extremely low shedding and powdering rates, effectively protecting the cleanliness of the stainless steel surface. Attached Figure Description

[0034] Figure 1 This is a flowchart of a method for preparing a green and environmentally friendly stainless steel sheet liner provided by the present invention.

[0035] Figure 2 This is a flowchart of the preparation method of chemically cross-linked starch-based polysaccharides provided by the present invention.

[0036] Figure 3 This is a flowchart of the preparation method of modified chitosan provided by the present invention.

[0037] Figure 4 This is a flowchart of the preparation method of modified nano-silica provided by the present invention. Detailed Implementation

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0039] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0040] Example 1: Basic Example This invention provides a green and environmentally friendly stainless steel sheet liner, such as... Figures 1-4 As shown, its preparation method includes the following steps: Preparation of chemically cross-linked starch-based polysaccharides (CMS-g-PAM): In a 500mL three-necked flask, add 100g corn starch (dry basis) and 150mL isopropanol. While stirring, add dropwise a solution of 30g NaOH dissolved in 50mL water, and alkalize at 35℃ for 1 hour.

[0041] 20 g of chloroacetic acid (dissolved in 30 mL of water) was slowly added, and the mixture was heated to 60 °C and reacted for 4 hours. After the reaction was completed, the mixture was neutralized, washed, and dried to obtain carboxymethyl starch (CMS), with a degree of substitution of 0.28.

[0042] Take 20g of the above CMS, add 150mL of water, and dissolve at 60℃. Under nitrogen protection, add 16g of acrylamide (AM).

[0043] Add 0.3 g potassium persulfate and 0.21 g sodium bisulfite (dissolved in 5 mL of water respectively), and react at 60 °C for 3 hours. The product is precipitated, washed, purified, and dried to obtain CMS-g-PAM.

[0044] Preparation of modified chitosan: Dissolve 10 kg of chitosan in 500 L of 1% (w / w) acetic acid solution to prepare a 2% chitosan solution. Add 9 kg of 2,3-epoxypropyltrimethylammonium chloride and react at 60 °C for 4 hours. Adjust the pH to 7.0-7.5 with 1 M NaOH solution.

[0045] Add 4 kg of PEG methyl ether methacrylate (grafting rate 40%) and 0.1 kg of potassium persulfate, and react at 70°C for 3 hours to obtain a modified chitosan solution.

[0046] Preparation of modified nano-silica: Take 10 kg of nano-silica (particle size 30 nm) and disperse it in Tris-HCl buffer at pH 8.5. Add 2.8 kg of dopamine and shake at room temperature for 12 hours.

[0047] The sample was collected by centrifugation, redispersed in ethanol, and 2.5 kg of mercaptopropyltriethoxysilane was added. The mixture was refluxed at 60 °C for 2 hours. After filtration and drying, modified nano-silica powder was obtained.

[0048] Preparation of backing paper: Surface anti-rust layer: Take 100 kg of bamboo pulp fiber (2 mm in length), disperse it in 2000 L of water to prepare a slurry of approximately 5%, add 5 kg of phytic acid, and stir for 40 minutes. Add 7 kg of citric acid and 0.07 kg of sodium hypophosphite, adjust the pH to 3.5, and react at 85℃ for 1.5 hours. Add 1.25 kg of the CMS-g-PAM prepared above, and stir for 30 minutes.

[0049] Intermediate buffer layer: Take 60 kg of PLA microfibers (5 μm in diameter and 5 mm in length) and 40 kg of cork pulp, disperse them in 1500 L of water, and prepare a pulp of about 4%. Add the above modified chitosan solution (2 kg based on dry chitosan) and stir for 1 hour.

[0050] Bottom support layer: Take 100kg of bamboo pulp fiber (3mm in length), disperse it in 1500L of water, and prepare a slurry of about 6%. Add 2kg of the above-mentioned modified nano silica (pre-dispersed) and stir for 1.5 hours.

[0051] Papermaking and post-processing: Three layers of pulp are sequentially formed using a three-layer paper machine. The wet paper sheet is pressed at 0.8 MPa for 1.5 minutes and dried at 100℃ to a moisture content of 8%. It is then hot-pressed at 135℃ and 1.5 MPa for 1.5 minutes, and finally soft-calendered at 70℃ and 0.3 MPa before being wound. The resulting liner paper has a basis weight of 85 g / m². 2 .

[0052] Example 2: High-buffering liner paper The difference from Example 1 is that the amount of PLA microfibers used in the intermediate buffer layer is 70 kg, and the amount of cork pulp is 30 kg. The amount of modified chitosan graft monomer (PEG methyl ether methacrylate) used is 50% of the chitosan mass. The remaining raw materials and preparation process are the same as in Example 1.

[0053] Example 3: High-strength backing paper The difference from Example 1 is that the amount of modified nano-silica used in the bottom support layer is 3 kg. The fiber used is 100% hemp pulp fiber (3-4 mm in length). The remaining raw materials and preparation process are the same as in Example 1.

[0054] Example 4: Long-lasting rust-proof backing paper The difference from Example 1 is that the amount of phytic acid used in the surface anti-rust layer is 8 kg, the amount of citric acid is 10 kg, and the crosslinking reaction time is extended to 2 hours. The remaining raw materials and preparation process are the same as in Example 1.

[0055] Example 5: Comprehensive Optimized Liner Paper Combining the advantages of embodiments 2, 3, and 4: Surface anti-rust layer: 8 kg phytic acid, 10 kg citric acid, crosslinking for 2 hours, 1.25 kg CMS-g-PAM.

[0056] Intermediate buffer layer: PLA microfiber 65kg, cork pulp 35kg, modified chitosan (grafting rate 50%) 2.5kg added.

[0057] Bottom support layer: hemp pulp fiber, modified nano-silica 3kg.

[0058] The preparation process is the same as in Example 1.

[0059] Example 6: Example verifying the key role of CMS-g-PAM The difference from Example 1 is that in the preparation of chemically cross-linked starch-based polysaccharide (CMS-g-PAM), the amount of acrylamide monomer was adjusted to a 1:1 mass ratio with CMS to obtain a higher grafting rate and more amide groups. The rest is the same as in Example 1.

[0060] Example 7: Example verifying the key role of modified chitosan The difference from Example 1 is that in the preparation of modified chitosan, the ratio of the quaternizing agent (2,3-epoxypropyltrimethylammonium chloride) to chitosan mass is 1.2:1, in order to introduce more quaternary ammonium positive charge. The rest is the same as in Example 1.

[0061] Comparative Example 1 (Unmodified Component) The difference from Example 1 is that: Intermediate buffer layer: Use an equal amount of ordinary chitosan (unquaternized-grafted) instead of modified chitosan.

[0062] Bottom support layer: Use an equal amount of unmodified nano-silica instead of modified nano-silica.

[0063] Surface anti-rust layer: Use an equal amount of ordinary cationic starch instead of CMS-g-PAM.

[0064] The remaining raw materials and preparation processes are exactly the same.

[0065] Comparative Example 2 (Traditional VCI backing paper) Commercially available rust-preventive paper containing nitrite (VCI) with a basis weight of 80 g / m² is used. 2 This is the closest existing technology representative.

[0066] Comparative Example 3 (without nano-reinforced backing paper) The difference from Example 1 is that no nano-silica is added to the bottom support layer. Everything else is exactly the same.

[0067] Comparative Example 4 (Single-layer structural liner paper) Using only the surface rust-preventive layer formulation and process of Example 1, a single-layer backing paper was prepared, with the basis weight adjusted to 85 g / m². 2 .

[0068] Comparative Example 5 (CMS-g-PAM only) The difference from Example 1 is that: Intermediate buffer layer: using ordinary chitosan; bottom support layer: using unmodified nano-silica.

[0069] The remaining raw materials and preparation processes are exactly the same.

[0070] Comparative Example 6 (modified chitosan only): The difference from Example 1 is that: The surface anti-rust layer uses ordinary cationic starch; the bottom support layer uses unmodified nano-silica.

[0071] The remaining raw materials and preparation processes are exactly the same.

[0072] Comparative Example 7 (modified nano-silica only): The difference from Example 1 is that: The surface anti-rust layer uses ordinary cationic starch; the intermediate buffer layer uses ordinary chitosan.

[0073] The remaining raw materials and preparation processes are exactly the same.

[0074] Performance testing Test method description: Tensile strength, wet tensile strength: GB / T 12914.

[0075] Bending stiffness: GB / T 22363, the lower the value, the more flexible.

[0076] Compression resilience: GB / T 8168.

[0077] Shedding and powder loss: ISO 15755.

[0078] Interlayer bond strength: TAPPI T541.

[0079] Rust prevention period: Observe the time it takes for the wrapped 304 stainless steel plate to show rust in a constant temperature and humidity chamber at 40℃ and RH90%.

[0080] Antibacterial properties: The inhibition zone was observed using the agar plate diffusion method according to GB / T 20944.1.

[0081] The test results are shown in Table 1 below: Table 1 Performance test data of the examples and comparative examples The results above show that the stainless steel sheet liner of the present invention simultaneously achieves high strength, high flexibility / buffering, durable rust prevention, high cleanliness, and environmental friendliness, and has broad market prospects.

[0082] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0083] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A green and environmentally friendly stainless steel sheet liner paper, characterized by, It is a three-layer composite structure, including a surface rust-proof layer, an intermediate buffer layer and a bottom support layer; The surface rust-proof layer comprises plant fibers cross-linked by citric acid and loaded with phytic acid and chemically cross-linked starch-based polysaccharides; The intermediate buffer layer comprises polylactic acid microfibers, softwood pulp and modified chitosan; The bottom support layer comprises plant fibers and modified nanosilica dispersed therein.

2. The green and environment-friendly stainless steel sheet liner paper according to claim 1, characterized in that, The surface rust-proof layer comprises, by weight: plant fibers 100 parts, phytic acid 3-8 parts, citric acid 5-10 parts, chemically cross-linked starch-based polysaccharides 0.5-2 parts; the intermediate buffer layer comprises, by weight: PLA microfibers 50-70 parts, softwood pulp 30-50 parts, modified chitosan 1-3 parts; the bottom support layer comprises, by weight: plant fibers 100 parts, modified nanosilica 1-3 parts.

3. The green and environment-friendly stainless steel sheet liner paper according to claim 1, characterized in that, The surface rust-proof layer comprises, by weight: plant fibers 100 parts, phytic acid 4-7 parts, citric acid 6-9 parts, chemically cross-linked starch-based polysaccharides 1-1.5 parts; the intermediate buffer layer comprises, by weight: PLA microfibers 55-65 parts, softwood pulp 35-45 parts, modified chitosan 1.5-2.5 parts; the bottom support layer comprises, by weight: plant fibers 100 parts, modified nanosilica 1.5-2.5 parts.

4. The green and environment-friendly stainless steel sheet liner paper according to claim 1, characterized in that, The surface rust-proof layer comprises, by weight: plant fibers 100 parts, phytic acid 5.5 parts, citric acid 7.5 parts, chemically cross-linked starch-based polysaccharides 1.25 parts; the intermediate buffer layer comprises, by weight: PLA microfibers 60 parts, softwood pulp 40 parts, modified chitosan 2 parts; the bottom support layer comprises, by weight: plant fibers 100 parts, modified nanosilica 2 parts.

5. The green and environment-friendly stainless steel sheet liner paper according to claim 1, characterized in that, The chemically cross-linked starch-based polysaccharides are carboxymethyl starch-polyacrylamide graft copolymers, and the preparation method is as follows: The starch is dispersed in an alcohol-water mixed solvent, and etherification reaction is carried out with chloroacetic acid under alkaline conditions to prepare carboxymethyl starch, and the degree of substitution is controlled to be 0.2-0.4; Carboxymethyl starch and acrylamide monomers are dissolved in water at a mass ratio of 1:(0.5-1); Graft copolymerization reaction is carried out at 50-70℃ under the action of an oxidation-reduction initiation system, the pH value of the reaction system is 7-9, and the reaction time is 2-4 hours to obtain carboxymethyl starch-polyacrylamide graft copolymers.

6. The green and environment-friendly stainless steel sheet liner paper according to claim 5, characterized in that, The alkaline conditions are provided by sodium hydroxide, and the molar ratio of sodium hydroxide to starch is (2.0-3.0):1; the molar ratio of chloroacetic acid to starch is (0.8-1.2):1; the etherification reaction temperature is 55-65℃, and the reaction time is 3-5 hours.

7. The green and environment-friendly stainless steel sheet liner paper according to claim 5, characterized in that, The oxidation-reduction initiation system is a potassium persulfate-sodium bisulfite system, wherein the addition amount of potassium persulfate is 1.0%-2.5% of the dry basis mass of the starch, and the molar ratio of sodium bisulfite to potassium persulfate is (0.8-1.2):

1.

8. The green eco-friendly stainless steel sheet liner paper according to claim 1, wherein the paper is coated with a coating layer containing a binder and a pigment. The modified chitosan is a product prepared by quaternization-grafting composite modification, and the preparation method is as follows: Quaternization of chitosan with 2,3-epoxypropyl trimethyl ammonium chloride at a mass ratio of 1:(0.8-1.2) at 55-65℃ for 3.5-4.5 hours; Subsequently, mixing with polyethylene glycol methyl ether methacrylate at 30%-50% of the mass of chitosan, and adding 0.5%-1% of the initial dry chitosan mass of potassium persulfate as an initiator; Reacting at 65-75℃ for 2.5-3.5 hours to obtain the modified chitosan.

9. The green eco-friendly stainless steel sheet liner paper according to claim 1, wherein the paper is coated with a coating layer containing a binder and a pigment. The modified nanosilica is a product prepared by polydopamine coating-silane coupling modification, and the preparation method is as follows: Dispersing nanosilica in a dopamine-Tris buffer solution with pH=8.3-8.7, and the mass ratio of nanosilica to dopamine is 1:(0.25-0.35); Polymerizing at room temperature for 11-13 hours for polydopamine coating; Subsequently, dispersing the coating product in an ethanol medium, and silanizing with mercaptopropyl triethoxysilane at 20%-30% of the mass of nanosilica at 55-65℃ for 1.5-2.5 hours to obtain the modified nanosilica.

10. A method for preparing the green eco-friendly stainless steel sheet liner paper according to any one of claims 1 to 9, characterized by, Comprising the following steps: (1) preparing a surface rust-proof layer slurry, an intermediate buffer layer slurry, and a bottom support layer slurry; (2) using a multi-layer paper machine to sequentially web the three layers of slurry, to make, and to dewater, a wet paper sheet; (3) dewatering the wet paper sheet by pressing; (4) drying and hot-pressing the dewatered paper sheet for setting, with a hot-pressing temperature of 120-150℃ and a pressure of 1-2MPa; (5) surface calendering the set paper sheet, and winding the product.

Images